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182402.00 / 187116.00 ● Final Report ● March 2020
Environmental Risk Assessments
& Preliminary Design of Seven Future
Wastewater Treatment
Systems in CBRM
New Waterford Wastewater Interception & Treatment System
Pre-Design Summary Report
Prepared by:
Prepared for:
New Waterford WW Interception &
Treatment System Pre-Design
Summary Report-Final
March 27, 2020 Darrin McLean James Sheppard Darrin McLean
New Waterford WW Interception &
Treatment System Pre-Design
Summary Report-Draft
March 2, 2020 Darrin McLean James Sheppard Darrin McLean
Issue or Revision Date Issued By: Reviewed By: Prepared By:
This document was prepared for the party indicated
herein. The material and information in the
document reflects HE’s opinion and best judgment
based on the information available at the time of
preparation. Any use of this document or reliance
on its content by third parties is the responsibility of
the third party. HE accepts no responsibility for any
damages suffered as a result of third party use of
this document.
182402.00 NEW WATERFORD SUMMARY REPORT 2020-05-05.DOCX/md ED: 18/11/2020 11:30:00/PD: 18/11/2020 11:31:00
164 Charlotte St.
PO Box 567
Sydney, NS
B1P 6H4
March 27, 2020
Matt Viva, P.Eng.
Manager Wastewater Operations
Cape Breton Regional Municipality (CBRM)
320 Esplanade,
Sydney, NS B1P 7B9
Dear Mr. Viva:
RE: New Waterford Wastewater Interception & Treatment System – Pre-Design
Summary Report
Enclosed, please find, for your files, a copy of the final draft of the Pre-Design Summary Report
for the New Waterford Wastewater Interception & Treatment System.
This report presents a description of proposed wastewater interception and treatment
infrastructure upgrades for the New Waterford Wastewater system, as well as an estimate of
the capital, operating costs, and replacement costs for the proposed infrastructure. In
addition, estimated costs of upgrades and assessments related to the existing wastewater
collection system are provided. Also, a desktop geotechnical review of the wastewater
treatment facility site is provided, along with an archaeological resources impact assessment
review for all sites of proposed wastewater infrastructure. Finally, an Implementation
Timeline is provided, which outlines a tentative schedule for implementation of the various
proposed wastewater system upgrades.
If you have any questions or require clarification on the content presented in the attached
report, please do not hesitate to contact us.
Yours very truly,
Harbour Engineering Joint Venture
Prepared by: Reviewed by:
Darrin McLean, MBA, FEC, P.Eng. James Sheppard, P.Eng.
Senior Municipal Engineer Civil Infrastructure Engineer
Direct: 902-539-1330 (Ext. 3138) Direct: 902-562-9880
E-Mail: dmclean@cbcl.ca E-Mail: jsheppard@dillon.ca
Project No: 182402.00 (CBCL)
187116.00 (Dillon)
HEJV New Waterford Wastewater System Pre-Design Summary Report i
Contents
CHAPTER 1 Introduction & Background ........................................................................................ 1
1.1 Introduction ........................................................................................................................ 1
1.2 Background ......................................................................................................................... 1
1.3 Description of Existing Wastewater Collection System ...................................................... 1
1.4 Service Area Population ...................................................................................................... 2
CHAPTER 2 Wastewater Interceptor System ................................................................................. 3
2.1 Description of Proposed Wastewater Interceptor Infrastructure ...................................... 3
2.2 Interception Infrastructure Land/Easement Acquisition Requirements ............................ 3
2.2.1 Lift Station Sites ...................................................................................................... 3
2.2.2 Linear Infrastructure ............................................................................................... 4
CHAPTER 3 Existing Wastewater Collection System Upgrades / Assessments ................................ 5
3.1 Sewage Pump Station Upgrades ......................................................................................... 5
3.2 Asset Condition Assessment Program ................................................................................ 5
3.3 Sewer Separation Measures ............................................................................................... 5
CHAPTER 4 Wastewater Treatment System .................................................................................. 6
4.1 Recommended Wastewater Treatment Facility ................................................................. 6
4.2 Wastewater Treatment Facility Land Acquisition Requirements ....................................... 7
4.3 Wastewater Treatment Facility Site Desktop Geotechnical Review .................................. 7
CHAPTER 5 Wastewater System Archaeological Resources Impact Assessment ............................. 8
5.1 Archaeological Resources Impact Assessment ................................................................... 8
CHAPTER 6 Wastewater Infrastructure Costs .............................................................................. 10
6.1 Wastewater Interception & Treatment Capital Costs ...................................................... 10
6.2 Wastewater Interception & Treatment Annual Operating Costs ..................................... 11
6.3 Annual Capital Replacement Fund Contribution Costs..................................................... 11
6.4 Existing Wastewater Collection System Upgrades / Assessment Costs ........................... 13
CHAPTER 7 Project Implementation Timeline ............................................................................. 14
7.1 Implementation Schedule ................................................................................................. 14
Appendices
A New Waterford Collection System Pre-Design Brief
B New Waterford Wastewater Treatment System Pre-Design Brief
C New Waterford Environmental Risk Assessment Report
D New Waterford Wastewater Treatment Facility Site Desktop Geotechnical Review
E New Waterford Wastewater System Archaeological Resources Impact Assessment
HEJV New Waterford Wastewater System Pre-Design Summary Report 1
CHAPTER 1 INTRODUCTION & BACKGROUND
1.1 Introduction
Harbour Engineering Joint Venture (HEJV) was retained by the Cape Breton Regional Municipality
(CBRM) to provide engineering services associated with the preliminary design of wastewater
interception and treatment infrastructure for the community of New Waterford, Nova Scotia as part
of the greater Environmental Risk Assessment and Preliminary Design of 7 Future Wastewater
Treatment Systems in CBRM project. This report presents a description of the proposed infrastructure
upgrades for the New Waterford Wastewater system, as well as an estimate of the capital, operating
and replacement costs for the proposed infrastructure. In addition, estimated costs of upgrades and
assessments related to the existing wastewater collection system are provided. Also, a desktop
geotechnical review of the wastewater treatment facility site is provided, along with an archaeological
resources impact assessment review for all sites associated with proposed wastewater infrastructure.
Finally, an Implementation Timeline is provided, which outlines a tentative schedule for
implementation of the various proposed wastewater system upgrades.
1.2 Background
The wastewater collection system in the community of New Waterford, as in many communities
throughout CBRM, currently discharges untreated wastewater to the Atlantic Ocean. The evolution of
the existing wastewater collection and disposal systems in CBRM included the creation of regions of a
community which were serviced by a common wastewater collection system tied to a local marine
outfall. Such design approaches have traditionally been the most cost-effective manner of providing
centralized wastewater collection, and the marine environment has long been the preferred receiving
water given the available dilution. Due to a changing regulatory environment, CBRM is working toward
intercepting and treating the wastewater in these communities prior to discharge.
The New Waterford system has been classified as low risk under the federal Wastewater System Effluent
Regulations (WSER) under the Fisheries Act, requiring implementation of treatment systems by the year
2040.
1.3 Description of Existing Wastewater Collection System
The New Waterford wastewater collection system includes the former Town of New Waterford, the
community of Scotchtown, and a small portion of River Ryan. This area drains to two wastewater
outfalls, both of which discharge at the Barachois. The system consists of approximately 70km of
HEJV New Waterford Wastewater System Pre-Design Summary Report 2
gravity sewer and 2.6km of force mains. There are also a number of lift stations within the system
located as follows:
Nicklewood Drive.
Columbus Street.
Oceanview Boulevard.
Hinchey Avenue.
New Waterford Highway (E-One systems).
E-One systems are individual home sewage pumping systems that discharge to a common pressure
sewer. In some instances, the flow is first discharged to a septic tank and the effluent from the septic
tank is pumped. In other instances, flow is pumped directly from the home.
The existing New Waterford collection system conveys sewage to two outfalls, both of which are
located at the Barachois.
1.4 Service Area Population
For New Waterford, the service area population was estimated to be 7,420 people in 3,735 residential
units. The population of the CBRM has been declining and this trend is expected to continue. Recent
population projection studies predict a 17.8% decrease in population in Cape Breton County between
2016 and 2036. For this reason, no allocation has been made for any future population growth.
For the purpose of preliminary design, wastewater infrastructure has been sized based on the current
population and measured flow data. While this may seem overly conservative, due to significant
amounts of inflow and infiltration (I&I) observed in sewer systems in the CBRM, a given population
decrease will not necessarily result in a proportional decrease in wastewater flow. Therefore, basing
the design on current conditions is considered the most reasonable approach.
HEJV New Waterford Wastewater System Pre‐Design Summary Report 3
CHAPTER 2 WASTEWATER INTERCEPTOR SYSTEM
2.1 Description of Proposed Wastewater Interceptor Infrastructure
The proposed wastewater interceptor system for the New Waterford Wastewater System includes
the following major elements:
A new sewage pumping station, LS‐NW#1 is to be constructed near the end of Beach Street.
A 750 mm diameter interceptor gravity sewer will collect flow from the existing sewer mains
that currently convey flow to the NW#1 outfall. The interceptor sewer will connect to the
existing sewer in three places to allow for a proper collection configuration to the proposed
LS‐NW#1 pump station.
The lift station will convey the intercepted sewage to the proposed WWTP site via a 400mm
diameter forcemain, 310m in length.
A combination air/vacuum release valve will be required at the high point, 56m from the lift
station along the forcemain alignment.
A new sewage pumping station, LS‐NW#2, is to be constructed near the proposed WWTP site
at the end of Mahon Street. This station is required to convey flow to the proposed WWTP
from the portion of the existing collection system that flows through the NW#2 outfall. A
30m length of 600mm diameter gravity sewer will re‐direct flow from the existing sewer
connected to the NW#2 outfall to the proposed pump station. A 10m length of forcemain,
150mm in diameter, will be required and will be connected to the forcemain described above
for LSNW‐ 1 to act as a common header to the proposed WWTP site.
A Combined Sewer Overflow (CSO) Station is to be constructed at each of the two new sewage
pumping station locations. These CSO Stations would direct wastewater to an overflow when
the flow rate in the interceptor sewer exceeds the design interception rate. No screens on
raw wastewater overflows at these CSO Stations would be constructed.
A detailed description of the proposed wastewater interceptor system, including preliminary layout
drawings is provided in Appendix A.
2.2 Interception Infrastructure Land/Easement Acquisition Requirements
2.2.1 Lift Station Sites
Construction of sewage pumping stations will require property acquisitions as shown in the table
below.
HEJV New Waterford Wastewater System Pre‐Design Summary Report 4
Table 1 ‐ Lift Station Sites Land Acquisition Requirements
PID# Property
Owner Assessed Value Description Size Required Purchase Entire
Lot (Y/N)
15482730 PWGSC $1,900 PS Site N/A Y
15006943 PWGSC $48,700 Access Road
10mx20m
(irregular
shape)
N
2.2.2 Linear Infrastructure
Installation of linear infrastructure such as pressure and gravity sewer piping and manholes will
require property acquisitions or easements as shown in the table below.
Table 2 ‐ Linear Infrastructure Land Acquisition Requirements
PID# Property
Owner Assessed Value Description Size Required Purchase Entire
Lot (Y/N)
15483092 Collieries
Parish $87,100 Forcemain
10m (Construction)
6m (Final)
X 75m length
N
15483100 PWGSC $8,600 Forcemain &
Gravity
N/A
Y
HEJV New Waterford Wastewater System Pre‐Design Summary Report 5
CHAPTER 3 EXISTING WASTEWATER COLLECTION SYSTEM
UPGRADES / ASSESSMENTS
3.1 Sewage Pump Station Upgrades
HEJV has reviewed the existing New Waterford Collection System for potential upgrades to the
existing sewage pumping stations. There are currently four pump stations in the community of New
Waterford. The age of the existing stations is on average 24‐years old. The New Waterford WWTP
has been classified as a low priority system and has an implementation deadline of 2040. Considering
that 2040 is 21‐years in the future, plans should be made to upgrade each of these stations as part of
the interception work to be completed in the community. Due to their age, the necessity to upgrade
these stations may occur prior to the implementation of the interceptor sewer project. Therefore,
the condition of each station should be verified at the time of detailed design to determine if an
upgrade of the existing station is required.
3.2 Asset Condition Assessment Program
To get a better sense of the condition of the existing New Waterford sewage collection system, HEJV
recommends completing a sewage collection system asset condition assessment program in the
community. The program would carry out an investigation involving two components:
1. Visual inspection and assessment of all manholes in the collection system;
2. Video inspection of 20% of all sewers in the system
The program should be completed with the issuance of a Collection System Asset Condition
Assessment Report that would summarize the condition of the various assets inspected and include
opinions of probable costs for required upgrades.
3.3 Sewer Separation Measures
CBRM should consider completing further sewer separation investigation efforts in New Waterford.
The program would review catch basins that are currently connected or possibly connected to existing
sanitary sewers. The program should also include the costing of the installation of new storm sewers
to disconnect catch basins from the existing sanitary sewer.
HEJV New Waterford Wastewater System Pre‐Design Summary Report 6
CHAPTER 4 WASTEWATER TREATMENT SYSTEM
4.1 Recommended Wastewater Treatment Facility
The recommended wastewater treatment facility for New Waterford is the Sequencing Batch Reactor
(SBR) process, which is an aerobic suspended‐growth biological treatment process. The SBR process
is a batch process whereby secondary treatment, including nitrification, is achieved in one reactor. It
involves a “fill and draw” type reactor where aeration and clarification occur in the same reactor.
Settling is initiated after the aeration cycle and supernatant is withdrawn through a decanter
mechanism. The WWTP would provide the following general features:
1. Preliminary treatment involving raw wastewater screening and grit removal;
2. Secondary treatment involving two continuous‐flow SBR tanks;
3. Disinfection of the treated wastewater with the use of ultraviolet (UV) disinfection unit;
4. Sludge management by means of aerated sludge holding tanks, sludge dewatering centrifuge
and associated bin room;
5. Odour control equipment;
6. Staff work spaces, including office space, laboratory space, control room, locker room, lunch
room, and washrooms;
7. Site access and parking, along with site fencing; and,
8. Extension of outfall NW2, including replacement of the existing outfall.
The proposed site of the New Waterford WWTP is located at the end of Mahon Street. The design
loads for the proposed WWTP are as shown in the table below.
Table 3 ‐ WWTP Design Loading Summary
Parameter Average Day Peak Day
Design Population 7,420
Flow (m3/day) 8,000 21,000
CBOD Load (kg/day) 890 1,780
TSS Load (kg/day) 670 1,340
TKN Load (kg/day) 100 200
A detailed description of the proposed wastewater treatment system, including preliminary layout
drawings is provided in Appendix B.
HEJV New Waterford Wastewater System Pre‐Design Summary Report 7
The associated Environmental Risk Assessment Report, which outlines effluent criteria for the
proposed wastewater treatment facility for New Waterford is provided in Appendix C.
4.2 Wastewater Treatment Facility Land Acquisition Requirements
Construction of the proposed wastewater treatment facility will require property acquisitions as
shown in the table below.
Table 4 ‐ WWTP Land Acquisition Requirements
PID# Property
Owner Assessed Value Description Size Required Purchase Entire
Lot (Y/N)
15483100 PWGSC $8,600 WWTP Site N/A Y
15006935 David Wilson $12,000 WWTP Site N/A Y
15484108 John Wilson
Sandra Wilson $85,300 WWTP Site N/A Y
15484090
David Allan
Wilson
Lori Anne
Wilson
$279,400 WWTP Site N/A Y
4.3 Wastewater Treatment Facility Site Desktop Geotechnical Review
A review of the subsurface soil conditions at the proposed site for the New Waterford Wastewater
Treatment Facility was carried out. In general, the review involved a field visit to the site to observe
the general conditions and a desktop review of available documents with the intent of commenting
on the following issues:
site topography;
geology (surficial ground cover, probable overburden soil and bedrock type);
geotechnical problems and parameters;
previous land use (review of aerial photographs);
underground/surface mining activities; and
proposed supplemental ground investigation methods (test pits and/or boreholes)
The following geotechnical issues were noted at the site:
1. There is evidence of the erodibility of subsurface soils and bedrock exposure along the Atlantic
coastline and a Coastal Protection Plan will be required for the site.
2. The area west and southwest of the proposed construction site was undermined due to
historical coal mining activities and there is a potential for undocumented bootleg pits/mines
in the area.
3. There is the potential for a layer of limestone to be present underlying the surficial ground
and alternating layers of bedrock below the site. Limestone is water soluble and has the
potential to develop karsts voids (sinkholes).
The review recommends an intrusive borehole program on the site to further define the subsurface
conditions.
A copy of the New Waterford WWTP site geotechnical review report is provided in Appendix D.
HEJV New Waterford Wastewater System Pre‐Design Summary Report 8
CHAPTER 5 WASTEWATER SYSTEM ARCHAEOLOGICAL
RESOURCES IMPACT ASSESSMENT
5.1 Archaeological Resources Impact Assessment
In October 2018, Davis MacIntyre & Associates Limited conducted a phase I archaeological resource
impact assessment at sites of proposed new wastewater infrastructure for the New Waterford
Wastewater System. The assessment included a historic background study and reconnaissance in
order to determine the potential for archaeological resources in the impact area and to provide
recommendations for further mitigation, if necessary.
The historic background study indicates that the study area was occupied at least as early as the late
19th century and residential buildings as well as mine features occupied the nearby vicinity. First
Nations peoples were known to have been present at nearby Lingan, as were European settlers in the
18th century. However, the field reconnaissance indicated that the majority of the study area has
been significantly altered over time, in part due to mining activities and their subsequent
abandonment, but also in relation to development of the government harbour at the Barachois. The
nearby cemetery is located well outside the study area and is a well‐established modern cemetery
whose bounds are believed to be well‐defined. Therefore, the study area has been determined to be
of low potential for intact archaeological resources and no further active archaeological mitigation is
recommended for the project.
However, in the unlikely event that any archaeological resources are encountered at any time during
ground disturbance, it is required that all activity cease and the Coordinator of Special Places (902‐
424‐6475) be contacted immediately regarding a suitable method of mitigation. Furthermore, in the
event that development plans change so that areas not evaluated as part of this assessment will be
impacted, it is recommended that those areas be assessed by a qualified archaeologist.
Finally, it is recommended that, if available, a qualified palaeontologist or geologist be contracted to
examine any bedrock exposed during the project excavation, and to determine the need for any
further paleontological monitoring.
HEJV New Waterford Wastewater System Pre‐Design Summary Report 9
A copy of the detailed New Waterford Wastewater System Archaeological Resources Impact
Assessment Report is provided in Appendix E. It should be noted that this report was registered with
the Nova Scotia Department of Communities, Culture and Heritage in April 2019.
HEJV New Waterford Wastewater System Pre‐Design Summary Report 10
CHAPTER 6 WASTEWATER INFRASTRUCTURE COSTS
6.1 Wastewater Interception & Treatment Capital Costs
An opinion of probable capital cost for the recommended wastewater interception and treatment
system for New Waterford is presented in the table below.
Table 5 ‐ New Waterford Wastewater Interception & Treatment System Capital Costs
Project Component Capital Cost (Excluding Taxes)
Wastewater Interception System $2,114,000
Wastewater Interception System Land Acquisition $11,000
Subtotal 1:$2,125,000
Construction Contingency (25%):$529,000
Engineering (10%):$211,000
Total Wastewater Interception: $2,865,000
Wastewater Treatment Facility $18,044,000
Wastewater Treatment Facility Land Acquisition $300,000
Subtotal 2:$18,344,000
Construction Contingency (25%):$4,511,000
Engineering (12%):$2,165,000
Total Wastewater Treatment: $25,020,000
Total Interception & Treatment System: $27,885,000
HEJV New Waterford Wastewater System Pre‐Design Summary Report 11
6.2 Wastewater Interception & Treatment Annual Operating Costs
An opinion of probable annual operating costs for the recommended wastewater interception and
treatment system for New Waterford is presented in the table below.
Table 6 ‐ New Waterford Wastewater Interception & Treatment System Operating Costs
Project Component Annual Operating Cost
(Excluding Taxes)
Wastewater Interception System
General Linear Maintenance Cost $500
General Lift Station Maintenance Cost $7,000
Employee O&M Cost $7,000
Electrical Operational Cost $27,000
Backup Generator O&M Cost $6,300
Total Wastewater Interception Annual Operating Costs: $47,800
Wastewater Treatment Facility
Staffing $400,000
Power $111,000
Chemicals $20,000
Sludge Disposal $130,000
Maintenance Allowance $21,000
Total Wastewater Treatment Annual Operating Costs: $682,000
Total Interception & Treatment System Annual Operating Costs: $729,800
6.3 Annual Capital Replacement Fund Contribution Costs
The CBRM wishes to create a Capital Replacement Fund to which annual contributions would be made
to prepare for replacement of the wastewater assets at the end of their useful life. The calculation of
annual contributions to this fund involves consideration of such factors as the type of asset, the asset
value, the expected useful life of the asset, and the corresponding annual depreciation rate for the
asset. In consideration of these factors, the table below provides an estimate of the annual
contributions to a capital replacement fund for the proposed new wastewater interception and
treatment system infrastructure. This calculation also adds the same contingency factors used in the
calculation of the Opinion of Probable Capital Cost, to provide an allowance for changes during the
design and construction period. The actual Annual Capital Replacement Fund Contributions will be
HEJV New Waterford Wastewater System Pre‐Design Summary Report 12
calculated based on the final constructed asset value, the type of asset, the expected useful life of the
asset, and the corresponding annual depreciation rate for the asset type. Please note that costs
shown below do not account for annual inflation and do not include applicable taxes.
Table 7 ‐ New Waterford Wastewater Interception & Treatment System Capital Replacement Fund
Costs
Description of Asset Asset Value
Asset Useful
Life
Expectancy
(Years)
Annual
Depreciation
Rate (%)
Annual Capital
Replacement
Fund
Contribution
Wastewater Interception System
Linear Assets (Piping, Manholes and
Other) $524,030 75 1.3% $6,812
Pump Station Structures (Concrete
Chambers, etc.) $874,280 50 2.0% $17,486
Pump Station Equipment (Mechanical
/ Electrical) $715,320 20 5.0% $35,766
Subtotal $2,113,630 ‐ ‐ $60,064
Construction Contingency (Subtotal x 25%): $15,016
Engineering (Subtotal x 10%): $6,006
Wastewater Interception System Annual Capital Replacement Fund Contribution
Costs: $81,086
Wastewater Treatment System
Treatment Linear Assets (Outfall and
Yard Piping, Manholes and Other) $2,000,000 75 1.3% $27,000
Treatment Structures (Concrete
Chambers, etc.) $7,500,000 50 2.0% $150,000
Treatment Equipment (Mechanical /
Electrical, etc.) $8,600,000 20 5.0% $430,000
Subtotal $18,100,000 ‐ ‐ $607,000
Construction Contingency (Subtotal x 25%): $152,000
Engineering (Subtotal x 12%): $73,000
Wastewater Treatment System Annual Capital Replacement Fund Contribution
Costs: $832,000
Total Wastewater Interception & Treatment Annual Capital Replacement Fund
Contribution Costs: $913,086
HEJV New Waterford Wastewater System Pre‐Design Summary Report 13
6.4 Existing Wastewater Collection System Upgrades / Assessment Costs
The estimated costs of upgrades and assessments related to the existing wastewater collection
system as described in Chapter 3 are shown in the table below.
Table 8 ‐ Existing Wastewater Collection System Upgrades / Assessment Costs
Item Cost
Sewage Pump Station Upgrades
Pump Station Infrastructure (controls, pumps, etc.) $841,000
Backup Power Generation $211,000
Engineering (12%) $126,000
Contingency (25%) $263,000
Total $1,441,000
Collection System Asset Condition Assessment Program
Condition Assessment of Manholes based on 825 MH’s $155,000
Condition Assessment of Sewer Mains based on 14 km’s of infrastructure $125,000
Total $280,000
Sewer Separation Measures
Separation based on 70km’s of sewer @ $45,000/km $3,150,000
Engineering (10%) $315,000
Contingency (25%) $788,000
Total $4,253,000
Total Estimated Existing Collection System Upgrade and Assessment Costs $5,974,000
HEJV New Waterford Wastewater System Pre‐Design Summary Report 14
CHAPTER 7 PROJECT IMPLEMENTATION TIMELINE
7.1 Implementation Schedule
Figure 1 provides a tentative schedule for implementation of wastewater system upgrades for New
Waterford, including proposed wastewater interception and treatment infrastructure as well as
upgrades to and assessment of the existing collection system.
For the Low Risk systems such as New Waterford, it is expected that implementation of proposed
upgrades will proceed on a staggered basis over the next 20 years as dictated by funding availability.
As each of these systems have the same target deadline, the prioritization will likely depend on not
only the availability of funding but also external factors. As the prioritization of the low risk systems
is not currently known, the project implementation schedule has been tentatively outlined on a
generalized basis (Year 1, Year 2, etc.) rather than with specified deadlines.
The schedule has been structured such that, in Year 1, asset condition assessments and investigations
to locate sources of extraneous water entering the system would be carried out. The two subsequent
years are allotted for design/construction of recommended upgrades, however, it is conceivable that
this could be completed in one year, depending on the scope of work required. It is proposed that,
during the following year, a follow‐up wastewater flow metering program would be carried out to
confirm design flows for new infrastructure and gauge the effect of upgrades to the existing collection
system. The subsequent four years after the follow‐up flow metering program have been allotted to
carry out design/construction of the new interception and treatment system. However, it is
conceivable that this work could be completed within three (3) years. This results in a tentative
implementation schedule that covers an eight (8) year timeline, which as noted above could be
compressed to six (6) years to align with typical funding programs for major infrastructure.
It should be noted that, although the process of pursuing the acquisition of properties and easements
required to construct the proposed wastewater upgrades as outlined in previous sections is not shown
on the Project Implementation Schedule, it is recommended that the CBRM pursue these acquisitions
prior to the commencement of detailed design.
No. Project Component Period: Jan ‐ Mar Apr ‐ Jun Jul ‐ Sept Oct ‐ Dec Jan ‐ Mar Apr ‐ Jun Jul ‐ Sept Oct ‐ Dec Jan ‐ Mar Apr ‐ Jun Jul ‐ Sept Oct ‐ Dec Jan ‐ Mar Apr ‐ Jun Jul ‐ Sept Oct ‐ Dec
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:$20,000
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Figure 1 ‐ Project Implementation Schedule New Waterford Wastewater System
1234
1
Year:
$155,000
Carry out video inspection and assessment of selected sanitary sewers in the existing collection system2
$125,000
11 Carry out tendering, construction, commissioning and initial systems operations for proposed
wastewater treatment infrastructure
Carry out detailed design for proposed wastewater treatment infrastructure
Carry out asset condition assessment of all manholes in the existing collection system
Carry out Sewer Separation Investigation Study to locate sources of extraneous water entering the
collection system
Carry out asset condition assessment of all sewage pumping stations in the existing collection system
Carry out detailed design for recommended upgrades to the existing collection system based on
previous assessments
Carry out tendering, construction and commissioning for recommended upgrades to the existing
collection system
Carry out flow metering and wastewater testing in the existing collection system to confirm
wastewater flows and organic loading
3
4
5
6
7
$30,000
10
9 Carry out tendering, construction, commissioning and initial systems operations for proposed
wastewater interception infrastructure
Carry out detailed design for proposed wastewater interception infrastructure8
$50,000
$88,200 $88,200
$2,758,800 $2,758,800
No. Project Component Period: Jan ‐ Mar Apr ‐ Jun Jul ‐ Sept Oct ‐ Dec Jan ‐ Mar Apr ‐ Jun Jul ‐ Sept Oct ‐ Dec Jan ‐ Mar Apr ‐ Jun Jul ‐ Sept Oct ‐ Dec Jan ‐ Mar Apr ‐ Jun Jul ‐ Sept Oct ‐ Dec
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Schedule:
Cash Flow:
Carry out asset condition assessment of all manholes in the existing collection system
Carry out video inspection and assessment of selected sanitary sewers in the existing collection system
Carry out Sewer Separation Investigation Study to locate sources of extraneous water entering the
collection system
Carry out asset condition assessment of all sewage pumping stations in the existing collection system
New Waterford Wastewater System
5678
Figure 1 ‐ Project Implementation Schedule
Year:
$24,154,000
Carry out tendering, construction, commissioning and initial systems operations for proposed
wastewater treatment infrastructure11
10
1
2
3
4
5
6
7
Carry out detailed design for recommended upgrades to the existing collection system based on
previous assessments
Carry out tendering, construction and commissioning for recommended upgrades to the existing
collection system
Carry out flow metering and wastewater testing in the existing collection system to confirm
wastewater flows and organic loading
Carry out detailed design for proposed wastewater interception infrastructure
Carry out tendering, construction, commissioning and initial systems operations for proposed
wastewater interception infrastructure
8
9
$84,400
$2,780,600
$866,000
Carry out detailed design for proposed wastewater treatment infrastructure
HEJV New Waterford Wastewater System Pre‐Design Summary Report Appendices
APPENDIX A
New Waterford Collection System Pre‐
Design Brief
187116 ●Final Brief ●April 2020
Environmental Risk Assessments & Preliminary
Design of Seven Future Wastewater Treatment
Systems in CBRM
New Waterford Collection System Pre-Design Brief
Prepared by: HEJVPrepared for: CBRM
March 2020
March 27, 2020
275 Charlotte Street
Sydney, Nova Scotia
Canada
B1P 1C6
Tel: 902-562-9880
Fax: 902-562-9890
_________________
NEW WATERFORD COLLECTION SYSTEM PRE DESIGN BRIEF 09OCT20119/ek
ED: 20/04/2020 11:58:00/PD: 20/04/2020 11:58:00
April 20, 2020
Matthew D. Viva, P.Eng.
Manager of Wastewater Operations
Cape Breton Regional Municipality
320 Esplanade, Sydney, NS B1P 7B9
Dear Mr. Viva:
RE: Environmental Risk Assessments & Preliminary Design of Seven Future
Wastewater Treatment Systems in CBRM – New Waterford Collection
System Pre-Design Brief
Harbour Engineering Joint Venture (HEJV) is pleased to submit the following
Collection System Pre-Design Brief for your review and comment. This Brief
summarizes the interceptors, local sewers and pumping station that will form
the proposed wastewater collection for the community of New Waterford. The
collection system will convey sewage to a future Wastewater Treatment Facility
that will be located north east of Mahon Street. The Brief also outlines the
design requirements and standards for the required collection system
infrastructure components.
Yours very truly,
Harbour Engineering Joint Venture
Prepared by: Reviewed by:
James Sheppard, P.Eng. Darrin McLean, MBA, FEC, P.Eng.
Civil Infrastructure Engineer Senior Civil Engineer
Direct: 902-562-9880 Direct: 902-539-1330
E-Mail:jsheppard@dillon.ca E-Mail:dmclean@cbcl.ca
Project No: 187116 (Dillon) and 182402.00 (CBCL)
March 27, 2020
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief i
Contents
CHAPTER 1 Introduction & Background ........................................................................................... 1
1.1 Introduction ................................................................................................................... 1
1.2 System Background ........................................................................................................ 1
CHAPTER 2 Design Parameters & Standards .................................................................................... 3
2.1 General Overview ........................................................................................................... 3
2.2 Design Standards ............................................................................................................ 3
CHAPTER 3 Wastewater Interceptor Pre- Design ............................................................................. 5
3.1 General Overview ........................................................................................................... 5
3.2 Design Flows .................................................................................................................. 5
3.2.1 Theoretical Flow ................................................................................................. 5
3.2.2 Observed Flow .................................................................................................... 6
3.2.3 Flow Conclusions & Recommendations ............................................................... 8
3.2.4 Wet Weather Conditions Assessment ................................................................. 9
3.3 Interceptor System ....................................................................................................... 10
3.4 Combined Sewer Overflows.......................................................................................... 12
3.5 Pumping Stations ......................................................................................................... 13
3.5.1 Pumping Design Capacity .................................................................................. 13
3.5.2 Safety Features ................................................................................................. 14
3.5.3 Wetwell ............................................................................................................ 14
3.5.4 Station Piping.................................................................................................... 15
3.5.5 Equipment Access ............................................................................................. 15
3.5.6 Emergency Power ............................................................................................. 15
3.5.7 Controls ............................................................................................................ 15
3.5.8 Security ............................................................................................................ 16
CHAPTER 4 Existing Collection System Upgrades ........................................................................... 17
4.1 Sewage Pump Station Upgrades ................................................................................... 17
4.2 Asset Condition Assessment Program ........................................................................... 17
4.3 Sewer Separation Measures ......................................................................................... 17
CHAPTER 5 Pipe Material Selection and Design ............................................................................. 18
5.1 Pipe Material ................................................................................................................ 18
CHAPTER 6 Land and Easement Requirements .............................................................................. 20
6.1 Lift Station Sites............................................................................................................ 20
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief ii
6.2 WWTP Site ................................................................................................................... 20
6.3 Linear Infrastructure ..................................................................................................... 21
CHAPTER 7 Site Specific Constraints ............................................................................................... 22
7.1 Construction Constraints .............................................................................................. 22
7.2 Environmental Constraints ........................................................................................... 22
7.3 Access Requirements.................................................................................................... 22
7.4 Power Supply Requirements ......................................................................................... 23
CHAPTER 8 Opinion of Probable Costs ........................................................................................... 24
8.1 Opinion of Probable Costs ............................................................................................ 24
8.2 Opinion of Operating Costs ........................................................................................... 24
8.3 Opinion of Existing Collection System Upgrades and Assessment Costs ........................ 25
8.4 Opinion of Annual Capital Replacement Fund Contributions ......................................... 26
CHAPTER 9 References ................................................................................................................... 27
Tables
Table 2-1 Sewer Design Criteria ............................................................................................... 3
Table 2-2 Pumping Station Design Criteria ............................................................................... 4
Table 3-1 Theoretical Flow Summary ....................................................................................... 6
Table 3-2 Flow Monitoring Location Summary ......................................................................... 7
Table 3-3 Average Dry Weather and Design Flows Results ....................................................... 7
Table 3-4 NW#1 outfall interpolation ....................................................................................... 8
Table 3-5 Adjusted Design Flows .............................................................................................. 8
Table 3-6 Observed Flows during Rainfall Events...................................................................... 9
Table 3-7 Pump Station Summary .......................................................................................... 14
Table 3-8 Wetwell Sizing Summary ........................................................................................ 14
Table 5-1 Comparison of Pipe Materials ................................................................................. 18
Table 6-1 Lift Station Land Acquisition Details ........................................................................ 20
Table 6-2 WWTP Land Acquisition Details .............................................................................. 21
Table 6-3 Linear Infrastructure Land Acquisition Details ......................................................... 21
Table 8-1 Annual Operations and Maintenance Cost .............................................................. 24
Table 8-2 Estimated Existing Collection System Upgrade and Assessment Costs..................... 26
Table 8-3 Estimated Annual Capital Replacement Fund Contributions.................................... 26
Appendices
Appendix A –Drawings
Appendix B – Flow Master Reports
Appendix C – Opinion of Probable Construction Costs
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 1
CHAPTER 1 INTRODUCTION &BACKGROUND
1.1 Introduction
Harbour Engineering Joint Venture (HEJV) has been engaged by the Cape Breton Regional
Municipality (CBRM) to carry out Environmental Risk Assessments (ERAs) and Preliminary Design of
seven future wastewater treatment Systems in the CBRM. The future wastewater collection and
treatment systems will serve the communities of Glace Bay, Port Morien, North Sydney & Sydney
Mines, New Waterford, New Victoria, Louisbourg and Donkin, which currently have no wastewater
treatment facilities.
The preliminary design of the wastewater interceptor systems are being completed as an addition to
the existing wastewater systems in each community. In general, the proposed interceptor sewers
will convey wastewater from the existing outfalls to the proposed Wastewater Treatment Plant
(WWTP) in each location. The complexity of each system is directly related to the number of
outfalls, geographic size and topography of each community. In general, the scope of work on the
interceptor system generally includes the following:
®Determination of design wastewater flows;
®Making recommendations on the best sites for proposed wastewater treatment facilities;
®Development of the most appropriate and cost-effective configurations for wastewater
interception; and,
®Estimation of capital and operations costs for recommended wastewater components.
This document relates to the interceptors, local sewers and pumping stations that will form the
wastewater interceptor system for the proposed WWTP in the community of New Waterford. This
brief outlines the design requirements and standards for the required infrastructure components.
Information regarding the preliminary design of the proposed wastewater treatment facility for New
Waterford will be provided in a separate Design Brief.
1.2 System Background
There are two wastewater sewersheds in the community of New Waterford. The sewersheds
employ a combination of gravity sewers and pumped systems to convey sewage. Pipe sizes in the
gravity network range from 200 to 750mm in diameter. There are several pumping stations in the
existing collection system including Nicklewood Drive, Columbus Street, Oceanview Boulevard and
Hinchey Avenue.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 2
Details for each of the pump stations are as follows:
®Nicklewood Drive – located at the southern end of Nicklewood Drive
o Installed in 1996;
o Duplex submersible station with 30hp pumps;
o Does not have emergency backup power;
o Does not have an emergency overflow; and,
o Station pumps flow to a high point on Ryan Street;
®Oceanview Boulevard – located at the northern end of Oceanview Boulevard
o Installed in 1996;
o Duplex submersible station;
o Does not have emergency backup power;
o Does have an emergency overflow complete with a septic tank; and,
o Station pumps flow to a high point on Hinchey Avenue.
®Columbus Street – located at the southern end of Columbus Street
o Installed in 1996;
o Duplex submersible station;
o Does not have emergency backup power;
o Does have an emergency overflow; and,
o Station pumps flow to a high point on Ryan Street.
®Hinchey Avenue – located west of Ocenview Boulevard.
o Duplex submersible station;
o Does not have emergency backup power;
o Does have an emergency overflow; and,
o Station pumps flow to a high point on Hinchey Avenue (approximately 450m to the
west).
The existing New Waterford collection system conveys sewage to two outfalls, both of which are
located at the Barachois. Not much information is known about the NW#1 outfall. The gravity
network upstream of the outfall is 750mm in diameter. The outfall is submerged and is adjacent to
the community wharf/breakwater. The NW#2 outfall is located east of the northern end of Mahon
Street. The outfall is 450mm in diameter. The outfall is constructed on the shoreline and is concrete
encased.
A drawing of the existing New Waterford sewer system is located in Appendix A for reference.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 3
CHAPTER 2 DESIGN PARAMETERS &STANDARDS
2.1 General Overview
The development of a wastewater interceptor system for each of the communities is highly
dependent upon the selection of appropriate design parameters. HEJV has reviewed applicable
design standards and has developed the preliminary design of the interceptor sewer to meet and
exceed these industry standards.
2.2 Design Standards
The design of the interceptor system has been based on the following reference documents and
standards:
®Atlantic Canada Wastewater Guidelines Manual for Collection, Treatment, and Disposal
(ACWGM) (Environment Canada, 2006); and
®Water Environment Federation: Manual of Practice FD-4, Design of Wastewater and
Stormwater Pumping Stations.
The key design criteria that have been established for this project are presented in Table 2-1 and
Table 2-2.
Table 2-1 Sewer Design Criteria
Description Unit Design Criteria Source Comments
Hydraulic Capacity l/s Location dependent HEJV Flow has been set to
minimize overflow events.
See discussion in Chapter 3.
Material for forcemains PVC, HDPE or ductile iron
pipe with the specified
corrosion protection
CBRM See discussion in Chapter 5
Minimum forcemain velocity m/s 0.6 ACWGM For self-cleansing purposes
Forcemain minimum depth of
cover
m 1.8 ACWGM Subject to Interferences
Material of gravity pipe PVC or Reinforced
concrete
CBRM See discussion in Chapter 5
Hydraulic design gravity Manning’s Formula ACWGM n = 0.013
Hydraulic design forcemain Hazen Williams Formula ACWGM C = 120
Maximum spacing between
manholes
m 120 for pipes up to and
including 600 mm and 150
for pipes over 600 mm
ACWGM
Gravity pipe minimum design
flow velocity
m/s 0.6 ACWGM
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 4
Description Unit Design Criteria Source Comments
Gravity pipe maximum flow
velocity
m/s 4.5 ACWGM
Pipe crossings separation mm 450 minimum Minimum separation must
also meet Nova Scotia
Environment (NSE)
requirements.
Horizontal pipe separation
forcemain to watermain
m 3.0 NSE
Horizontal pipe separation
gravity pipe to water main
m 3.0 ACWGM Can be laid closer if the
installation meets the
criteria in Section 2.8.3.1
Gravity pipe minimum depth
of cover
m 1.5 HEJV Subject to Interferences
Gravity pipe maximum depth
of cover
m 4.5 HEJV Subject to Interferences.
Increased depth may be
considered where
warranted
Table 2-2 provides a summary of the key design criteria for the Pumping Stations.
Table 2-2 Pumping Station Design Criteria
Description Unit Design Criteria Source Comments
Pump cycle time 1 hour 5 < cycle <10 WEF/
ACWGM
Number of pumps Minimum of two. Must be
able to pump design flow
with the largest pump out
of service.
ACWGM Three minimum for stations
with flows greater than 52
l/s.
Inlet sewer One maximum ACWGM Only a single sewer entry is
permitted to the wetwell.
Header pipe diameter mm 100 minimum ACWGM
Solids handling mm 75 (minimum)ACWGM Smaller diameter
permissible for macerator
type pumps.
Emergency power
generation
To be provided for firm
capacity of the facility.
ACWGM Can employ overflow
options per 3.3.1. Option to
run one pump if conditions
of 3.3.5.1 are met.
Pump station wetwell
ventilation
Air
changes/
hour
30 (Wetwell)
12 (Valve Chamber)
ACWGM Based on intermittent
activation when operating
in the wet well.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 5
CHAPTER 3 WASTEWATER INTERCEPTOR PRE-DESIGN
3.1 General Overview
A drawing of the existing New Waterford collection system has been included in Appendix A. The
drawing was created using background data collected from various sources to depict the layout of
the existing sanitary sewer network.
The proposed wastewater interceptor system for New Waterford will include two sewage pump
stations. The first, LS-NW#1 will be located east of the northern end of Beach Street, adjacent to the
community wharf. A new gravity interceptor will connect with existing infrastructure and redirect
flow from the existing NW#1 outfall to a CSO chamber. Flow from the CSO chamber, under normal
conditions (as defined in this chapter) will be directed to a proposed sewage pump station. Flow
above normal conditions, will overflow though the CSO chamber, back to the existing NW1 outfall.
The pump station will convey wastewater via. A 400 mm diameter forcemain under Irish Brook to
the proposed WWTP, approximately 310 metres away. The second pump station, LS-NW#2, will
convey flow from the NW#2 outfall to the proposed WWTP. A gravity connection to the existing
sewer will be completed and direct flow from the NW#2 outfall to a proposed CSO chamber. The
CSO chamber will direct flow to the pump station under normal conditions (as defined in this
chapter) and to the NW#2 outfall during periods of excessive flows.
For this Pre-Design Brief, HEJV has compiled a preliminary plan and profile drawing of the proposed
linear infrastructure. The locations of the pump stations, existing outfalls and the proposed WWTP
location have also been illustrated on the drawings and are included in Appendix A.
3.2 Design Flows
HEJV completed a review of the theoretical and observed sanitary flows for the New Waterford
sewersheds. The purpose of the assessment was to estimate average and design flows for the
environmental risk assessment (ERA) and the preliminary design of the future WWTP and
interception system.
3.2.1 Theoretical Flow
Theoretical flow was calculated based on design factors contained in the ACWGM. The population
for the New Waterford sewer sheds was based on the 2016 Census data from CBRM’s GIS database
using the following procedure: Each residential unit within the sewer shed area boundary from
CBRM’s structure database was multiplied by the average household size for the census
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 6
dissemination area that it falls within. For New Waterford, the service area population was
estimated to be 7,420 people in 3,735 residential units. Population estimates are shown in Table 3-1
and Table 3-4. Peak design flow was calculated using the following equation (1):
ܳ(݀)=ܲݍܯ
86.4 +ܫܣ (1)
Where:
Q(d) = Peak domesƟc sewage flow (l/s)
P = PopulaƟon (in thousands)
q = Average daily per capita domesƟc flow (l/day per capita)
M = Peaking factor (Harman Method)
I = unit of extraneous flow (l/s)
A = Subcatchment area (hectares)
ACWGM recommends an average daily domestic sanitary flow of 340 l/day per person for private
residential dwellings. The unit of extraneous flow was assumed to be approximately 0.21 l/s/ha
based on typical ranges outlined in ACWGM. The peaking factor used in Equation 1 was determined
using the Harman Formula (2) shown below:
Harman Formula
ܯ =1+14
4+ܲ.ହ (2)
The estimated average dry weather flow (ADWF), 3.5xADWF and peak design flows based on the
ACWGM methods discussed above are presented in Table 3-1. Please note that the value of
3.5xADWF was recommended by UMA Engineering Limited as the minimum sewage flow rate that
should be treated for New Waterford in the report “Industrial Cape Breton Wastewater
Characterization Program – Phase II” prepared in 1994. As such, HEJV recommends this value be
carried forward as the minimum amount of sewage that should be treated for New Waterford.
Table 3-1 Theoretical Flow Summary
Station Estimated Area
(ha)
Estimated
Population1 ADWF2 (l/s)3.5x ADWF
(l/s)
Peak Design Flow3
(l/s)
NW#1 208 2910 11.45 40.08 83.22
NW#2 79 1046 4.11 14.39 32.18
1 2016 Cape Breton Census from StaƟsƟcs Canada
2Based on average daily sewer flows of 340 L/day/person (ACWGM 2006)
3EsƟmated using ACWGM equaƟon for peak domesƟc sewage flows (including extraneous flows and peaking factor)
3.2.2 Observed Flow
A summary of the flow meter deployment locations and monitoring durations are provided in Table
3- 2. Initially, HEJV installed one meter at the NW#2 outfall to be used to determine design flows for
the New Waterford Interceptor System and future WWTP. The flows that were obtained in the
February 28th to April 17th meter deployment were reviewed against values that had been previously
been captured by UMA Engineering in the 1990’s. The flows obtained from the initial flow metering
program were much larger than those collected in the past (near 3x’s larger). HEJV at that time
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 7
recommended to CBRM that a flow monitoring program should be conducted at both outfall sites to
confirm the data from the initial deployment as the larger NW#1 flows would be derived from the
larger than anticipated flows for the NW#2 outfall meter location.
Table 3-2 Flow Monitoring Location Summary
Station Northing Easting Monitoring Start-End Dates Days of Data
NW#1-Mahon
St.5125090.661 4609004.525 August 1-17, 2018 17
NW#2 –Mahon
St.5125090.661 4609004.525 February 28-April 17, 2018
August 1-22, 2018 71
Analysis for observed dry weather flows were completed using the United States Environmental
Protection Agency’s (EPA) Sanitary Sewer Overflow Analysis and Planning (SSOAP) toolbox. The
SSOAP toolbox is a suite of computer software tools used for capacity analysis and condition
assessments of sanitary sewer systems.
Flow and precipitation data were input into the SSOAP program, along with sewershed data for each
of the metered areas. To determine average dry weather flow (ADWF), days that were influenced by
rainfall were deleted. This was done in the SSOAP model by removing data from days that had any
rain within the last 24 hours, more than 5 mm in the previous 48 hours, and more than 5 mm per
day additional in the subsequent days (e.g. 10 mm in the last 3 days).
The calculated ADWF estimates based on monitored flow data evaluated using the SSOAP program
are presented in Table 3-3.
Table 3-3 Average Dry Weather and Design Flows Results
Monitoring Station ADWF From SSOAP
Model (l/s)
3.5x ADWF
(l/s)
Average Daily
Observed Flow (l/s)
Peak Daily
Average Flow
(l/s)
NW#1
(Monitored Portion)39.40 137.90 41.40 59.21
NW#2 8.90 35.60 13.44 73.31
Values for the remaining portion of the NW#1 sewershed were derived from the observed flow data
from the NW#1 outfall.Table 3-4 presents a summary of the collected and interpolated flows for
the NW#1 sewershed.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 8
Table 3-4 NW#1 outfall interpolation
Site Contributing Population Contributing Area (ha)3.5xADWF
From SSOAP Model(l/s)
NW#1
(Monitored Portion)2910 208 137.90
NW#1 (Not Monitored)3464 217 164.15
NW#1 Total 6374 425 302.05
3.2.3 Flow Conclusions & Recommendations
HEJV reviewed the data collected for NW#1 and NW#2. When the values obtained for ADWF were
converted to a per person value, it was noted that the values obtained in NW#1 were quite high,
and over 1000 l/p/d (liters/per person/day). The value returned for NW#1 was approximately 1200
l/p/d, and the value returned for NW#2 was 875 l/p/d. Please note that the calculation for NW#2
also contains the data that was collected during the initial flow metering program. In contrast, the
dry weather flows obtained during the second flow meter deployment, returned a value of 330
l/p/d. HEJV reviewed the existing collection system for a possible rationale as to why the flows were
so much higher for the NW#1 outfall. The average overnight flow minimums were examined for
both NW#1 and NW#2 sewershed data. The overnight minimum flow in NW#2 was 158 l/p/d and
520 l/p/d for NW#1. Wastewater production at 3am is typically very low, but not zero. If the
minimum flows in NW#2 are assumed to be reasonable for overnight flow, then NW#1 flows should
be able to approach this level during dry weather, in the absence of an industrial process that
discharges significant volumes at nights; therefore, the difference in overnight flow rates between
the two sewersheds is likely to be unnecessary extraneous flow. This may result from heavy
groundwater infiltration or from a stream entering the sewer in NW#1. Flow equivalent to (520-158
= 362 l/p/d) for the NW#1 sewershed was therefore removed from the design flows. Please see
Table 3-5 below for updated design flows that were utilized in the preliminary design of the
interceptor system.
Table 3-5 Adjusted Design Flows
Site
ADWF
(From SSOAP & Interpolation)
(l/s)
ADWF (reduction)
(l/s)
ADWF (Adjusted)
(l/s)
3.5xADWF
(Adjusted)
(l/s)
NW#1 86.30 26.70 59.60 208.60
NW#2 8.90 -8.90 31.15
Based on the analysis presented in the above sections, HEJV’s recommended design flow for LS-
NW#1 is 208.60 l/s based on the adjusted 3.5xADWF value. For LS-NW#2, HEJV recommends a
design flow of 31.15 l/s based on the 3.5XADWF value that was determined from the raw data
collected from both flow monitoring programs.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 9
As the New Waterford WWTP has been characterized as a low risk system, the implementation date
for the proposed work may not occur till 2040 (21 years into the future). HEJV recommends re-
visiting the above noted adjusted design flows during the detailed design of the project. Due to the
time span, there is opportunity for CBRM to complete upgrades to the existing system to reduce the
impact of I&I into the system. Concurrently, if no upgrades are made to the system, then the flow
conditions may increase, as the existing system may be further plagued by I&I issues. A future flow
monitoring program during detailed design would be recommended to confirm the final flows used
for the design of the New Waterford Interceptor Sewer and WWTP. The time span would also allow
for revisions to the design standards referenced in Chapter 2.2,which could impact the design flows
presented in Table 3-5.
3.2.4 Wet Weather Conditions Assessment
To evaluate performance of the proposed lift station during wet weather conditions, metered flows
during rainfall events have also been considered. A minimum rainfall depth of 10 mm is assumed to
be the minimum rainfall required to result in meaningful wet weather flows in the sewer. The
measured flow was compared to the recommended design flow to indicate if overflow is expected.
The results of the wet weather flow analysis can be seen in Table 3-6.
Table 3-6 Observed Flows during Rainfall Events
Monitoring Station
Minor Rainfall Event
(10-25 mm Daily Rainfall)
Major Rainfall Event
(>25 mm Daily Rainfall)
# of
Events
Daily
Average
Flow (l/s)
Expected Overflow1
(Y/N)# of Events Daily Average
Flow (l/s)
Expected
Overflow1
(Y/N)
NW#1 2 50 No Data Available
NW#2 7 24 N 1 43 Y
1 Overflow expected when observed flow exceeds design flow
It is important to note that only one rainfall event having daily rainfall amounts in excess of 25 mm
was measured during the monitoring period.
To consider the effects of moderate rainfall, daily rainfall for the Sydney CS climate station
(Environment Canada Station #8207502) was reviewed for the past 10 years of complete data (2008
– 2017). Review of these data suggests that moderate rainfall events (i.e. daily rainfall greater than
25 mm) are expected to occur frequently within a given year. Based on this review, it is expected
that these moderate rainfalls would occur on average between 10 and 15 times each year and
therefore overflow may be expected during these events.
Rapid snow melt may lead to additional overflow events, the occurrence of which would largely be
confined to the spring freshet season. According to the U.S. Environmental Protection Agency, peak
rainfall events establish peak sewer flows rather than snow melt (EPA 2007). This is reasonable
since snow is temporarily stored within the watershed as snow pack and gradually melts over time
(i.e. rather than sudden peak flows generated by intense rainfall).
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 10
Mean daily temperatures were reviewed during wet periods to consider the impacts of snow
accumulation and melt during the winter observation period. Mean temperatures were found to
be above 0oC for the precipitation events considered in this study. A few of the events occurred
with temperatures close to 0oC and are likely to have fallen as a rain-snow mix. Given these
relatively mild temperatures, it is expected that the SSOAP analysis generally accounted for snow-
melt wet weather inputs in estimating dry weather flows.
3.3 Interceptor System
The proposed interceptor system for the New Waterford WWTP is presented on the plan and profile
drawing attached in Appendix A. The proposed interceptor system is made up of segments of
pressure and gravity sewers and two new lift stations.
The first step in laying out the interceptor sewer route was to determine the optimal location of the
future WWTP that will serve the town of New Waterford. Historically, the Barachois has been
reviewed as the optimal location for a plant development. All of the sanitary sewer flow from the
community of New Waterford is conveyed to two sewer outfalls, both located at the Barachois site.
HEJV commenced with a review for a remote location in the Barachois area. In this case, a remote
location would be defined as being at least 150 m from isolated human habitation as required by
ACWGM. After reviewing the area it was concluded that there were no feasible sites to be
developed at the Barachois that met the 150m separation distance.
As part of our pre-design efforts, HEJV met with NSE to discuss locations for future treatment plants
that do not meet the ACWGM guidelines for setback distances, but ultimately make the most sense
for a community from an economic stand point. NSE’s feedback to HEJV was that if the location of
the WWTP did not meet the ACWGM guidelines but ultimately made the most sense for a
community, the detailed design of the plant would need to include odour controls, to minimize the
impact to neighbouring properties.
HEJV reviewed two sites in the area of the Barachois for suitability to construct the New Waterford
WWTP. Site #1 is on the west side of the Barrachois at the end of Mahon Street on PID’s 15006935,
15484108, and 15483100. Site #2 is on the east side of the Barrachois just west of the existing
cemetery at the end of Hudson Street on PID 15483100. The location of the two sites is shown on
Sheet 1 in Appendix A. The following provides a detailed review of the characteristics of each site as
it relates to the suitability for the location of the proposed WWTP. For purposes of this review a
fenced area approximately 90 m x 90 m is considered to be large enough to encompass the WWTP
buildings and to provide maneuvering space around the buildings for passage of large trucks that
would be required on site on a regular basis.
Site #1
The treatment plant buildings for Site #1 would be within 150 m of about 8 households on Mahon
Street. One household on PID 15484108 at the end of Mahon Street would have to be purchased
and removed to provide space for the new WWTP compound.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 11
Site #1 is moderately sloped and elevations across the site range from about 5.0m to about 8.0m.
The average elevation of Site #1 is approximately 6.5m.
During discussions with CBRM on the potential WWTP sites, a concern was expressed with regard to
erosion of the coastline north of Site #1. Accordingly, HEJV carried out a review of how much coastal
erosion has occurred over time at this site based on aerial photographs that date back to 1931. It
was noted that coastal erosion rates in that area range from about 0.2 m/year to about 0.6 m/year.
A projected coastline was then calculated to the year 2090, which assumes that the New Waterford
WWTP is built in 2040 and has a 50 year life expectancy. Assuming that the coastline erodes at a
rate of 0.3 m per year, this results in movement of the existing coastline to a point about 21m to the
south. The projected coastline is shown on Sheet 3 in Appendix A. The proposed WWTP compound
footprint is approximately 20 m to the south of the 2090 projected coastline. It is recommended
that shoreline protection measures such as armour stone be placed along the section of shoreline
that fronts the proposed location of the wastewater treatment plant to slow the pace of shoreline
erosion.
There are known underground coal mine workings and coal seams on Site #1 as depicted on Sheet 3
in Appendix A. This drawing shows the approximate location of the former Barrachois Mine
workings, as well as the approximate depth of cover over the Hub Coal Seam, which ranges in depth
from about 1 m to 21 m under Site #1. There is also the possibility that the Hub Coal Seam has
undocumented bootleg mines. The Harbour and Phalen Coal Seams and associated mine workings
also underlie Site #1, however those seams are quite deep – in the vicinity of 130 m and 275 m in
depth respectively and do not likely pose a risk of subsidence. Although there are known shallow
documented and possibly undocumented underground mine workings on the site, given their
shallow depth, it would not be unreasonable to assume that the workings could be located,
excavated and replaced with structural fill during construction of the WWTP.
The outfall for the WWTP Site #1 would likely be placed along a similar route as the current NW#2
outfall. A new outfall pipe from the WWTP would have to be placed on the ocean bottom to a
distance of approximately 150m from the existing shoreline to achieve a minimum 1.0m depth of
water over the end of the outfall pipe at low tide.
Site #2
The treatment plant buildings for Site #2 would be within 150 m of about 25 households fronting
various streets in the area, including Mahon Street, Clarke Avenue, Elm Avenue, Patrick Street, and
Hudson Street. There is a cemetery just west of Site #2.
Site #2 is moderately sloped and elevations across the site range from about 8.0m to about 4.0m.
The average elevation of Site #2 is approximately 6.0m.
The Harbour and Phalen Coal Seams and associated mine workings also underlie Site #2, however
those seams are quite deep – in the vicinity of 104 m and 250 m in respectively and do not likely
pose a risk of subsidence.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 12
The outfall for the WWTP Site #2 would likely be placed along a similar route as the current NW#1
outfall. A new outfall pipe from the WWTP would have to be placed on the ocean bottom to a
distance of approximately 200m from the existing shoreline to achieve a minimum 1.0m depth of
water over the end of the outfall pipe at low tide. At the very least, the new outfall pipe would likely
have to extend past the existing breakwater to the north of Site #2 to achieve sufficient effluent
dilution. The alignment of the new outfall pipe at the Site #2 location would likely extend past the
boating lane to the small harbour adjacent to the breakwater and, depending on the configuration
of armour stone pipe protection, it may create an impediment to boating traffic passing into and out
of the harbour.
Recommended Site
In consideration of the factors that influence the suitability of each site as the preferred location for
the New Waterford WWTP, including proximity to households, ease of site development, preferred
outfall pipe routing, coastal erosion and risk of subsidence due to underground mine workings, it is
recommended that Site #1 be chosen as the WWTP location. Given that the same parcel of land
encompasses Site #1 and Site #2, it is recommended that CBRM purchase the entire parcel rather
than a portion of the property. This would allow some flexibility in siting the WWTP in the future.
Proposed Interceptor System
The proposed interceptor system for the New Waterford WWTP is presented on the plan and profile
drawing attached in Appendix A. The major elements of the interceptor system include:
®LS-NW#1 located near the end of Beach Street. A 750 mm diameter interceptor gravity
sewer will collect flow from the existing sewer mains that currently convey flow to the
NW#1 outfall. The interceptor sewer will connect to the existing sewer in three places to
allow for a proper collection configuration to the proposed LS-NW#1 pump station.
®The lift station will convey the intercepted sewer to proposed WWTP site via a 400mm
diameter forcemain, 310m in length.
®A combination air/vacuum release valve will be required at the high point, 56m from the lift
station along the forcemain alignment.
®A second pump station, LS-NW#2, will be required to convey flow to the proposed WWTP
from the existing collection system that conveys to the NW#2 outfall. A 30m length of
600mm diameter gravity sewer will re-direct flow from the existing sewer connected to the
NW#2 outfall to the proposed pump station. A 10m length of forcemain, 150mm in
diameter, will be required and will be connected to the forcemain described above for LS-
NW-1 to act as a common header to the proposed WWTP site.
Flow Master Reports for the proposed linear infrastructure, illustrated on Sheet 1 in Appendix A,
have been included in Appendix B.
3.4 Combined Sewer Overflows
A Combined Sewer Overflow (CSO) should be utilized in the proposed interceptor system where
flows directed to a pump station exceed the interception design rate defined in Section 3.2.3. The
proposed locations for the chambers have been illustrated on the plan and profile drawing included
in Appendix A.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 13
In general, the interceptor system has been designed for a capacity of 3.5xADWF. The CSO
chambers depicted on the plan and profile drawing permit the connection to each of the existing
outfalls, while only permitting the recommended interception design flows (3.5xADWF) into the
proposed interceptor system.
For the proposed New Waterford interceptor sewer, CSO chambers are required at each of the
pump station sites. This will limit the flow to the pump station at a maximum of 3.5xADWF. Flow
above 3.5xADWF will be directed back to the existing NW#1 and upgraded NW#2 outfalls.
3.5 Pumping Stations
As discussed above, two new pumping stations will be required in the proposed New Waterford
interceptor system to convey wastewater to the proposed WWTP. The pump stations should be
equipped with non-clog submersible sewage pumps with an underground wetwell and a building
that will accommodate the mechanical piping, valves, electrical system, control systems and
instrumentation. The building for LS-NW#1 should be sized to house a backup generator. Due to its’
proximity, backup generation for LS-NW#2 should be provided from the proposed WWTP. A
hydraulic analysis should be completed on the forcemain to determine if surge valves are
warranted, in addition to the variable speed drives that are proposed for the proposed pump
stations (as described in Section 3.5.1). If required, the valves should be installed prior to the
forcemain exiting the lift station building to protect the pipe against unwanted surge forces. A
standard lift station schematic has been presented in Appendix A for illustrative purposes.
3.5.1 Pumping Design Capacity
The pump stations are designed to pump the intercepted flows defined in Section 3.2.2 with one
pump out of service. All pumps should be supplied and operated with variable frequency drives
(VFD). A VFD will provide the following benefits to the pumping system:
®Energy savings by operating the pump at its best efficiency point;
®Prevent motor overload;
®Energy savings by eliminating the surge at pump start up; and
®Water hammer mitigation.
3.5.1.1 BEACH STREET LIFT STATION –LS#1
This station will convey flow to the proposed WWTP from the NW#1 outfall. The pump station will
be a triplex station, with two duty and one standby pumps. These pumps should have a combined
capacity of 210 l/s, with a TDH of 15.15 m.
3.5.1.2 MAHON STREET LIFT STATION –LS#2
This station will convey flow to the proposed WWTP via a 150mm forcemain that will tie into the
NW#2 interceptor. The pump station will be a duplex station, with one duty and one standby pump.
These pumps should have a combined capacity of 32 l/s with a TDH of 11.11 m.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 14
3.5.1.3 PUMP STATION SUMMARY
Table 3-7 Pump Station Summary
Pumping Station Beach Street –LS-NW#1 Mahon Street –LS-NW#2
Duty Pumps 2 1
Standby Pumps 1 1
ADWF (L/s)59.60 8.90
Interception Design Flow (L/s)208.6 31.15
Pump Capacity
(L/s, each pump, Duty Pump(s) running)
210 32
Forcemain Diameter (mm)400 150
TDH (m) at Maximum Design Flow 15.15 11.11
Maximum Velocity (2 pumps running) m/s 1.7 1.8
Minimum Velocity (1 or 2 pump running) m/s 0.6 0.6
Approximate power requirement (each
pump) kW
26 5.6
3.5.2 Safety Features
The stations should report alarm conditions to the CBRM SCADA network. The stations should also
incorporate external visual alarms to notify those outside of the building of an alarm condition.
External audible alarms should not be used as the stations are in populated areas and disturbance to
the local community should be kept to a minimum.
All access hatches should include safety grating similar to Safe-Hatch by Flygt.
3.5.3 Wetwell
The wetwells should be constructed with a benched floor to promote self-cleansing and to minimize
any potential dead spots.
The size of the wetwells should be based on factors such as the volume required for pump cycling,
dimensional requirements to avoid turbulence problems, the vertical separation between pump
control points, the inlet sewer elevation, capacity required between alarm levels, overflow
elevations, the number of pumps and the required horizontal spacing between pumps.
The operating wetwell volumes for the pumping stations should be based on alternating pump
starts between available pumps while reducing retention times to avoid resultant odours from
septic conditions.
At this time HEJV recommends a precast unit for each station. Based on the conditions discussed
above, the sizing for each of the wetwells is presented below.
Table 3-8 Wetwell Sizing Summary
Pumping Station Size and Shape
(m)
Depth
(m)
Beach Street –LS-NW#1 2.4 x 3.6 Rectangular 8.1
Mahon Street –LS-NW#2 2.4 Circular 4.4
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 15
3.5.4 Station Piping
Pump station internal piping should be ductile iron class 350 with coal tar epoxy lining or stainless
steel with a diameter of 150 mm at the LS#2 and 400 mm at LS#1. Threaded flanges or Victaulic
couplings should be used for ductile iron pipe joints, fittings and connections within the station.
Pressed or rolled 15vanstone neck flanges should be used for stainless steel pipe joints, fittings and
connections. Piping layout should be designed to provide minimum friction loss and to provide easy
access to all valving, instrumentation and equipment for the operators.
A common flow meter on the discharge header should be provided for the stations to monitor
flows.
3.5.5 Equipment Access
Pump installaƟon and removal for the staƟons should be achieved using a liŌing davit and electric
hoist that would access the pumps through hatches located above the pumps. Due to maintenance
issues associated with exterior davit sockets and portable davits, staƟonary davits should be
installed inside these pump staƟons and accessed through a roll up door.
A heated building should be provided for each of the liŌ staƟons to eliminate maintenance issues
with valve chambers. All valves and instrumentaƟon should be above ground in the heated building
to allow for easy access and maintenance.
3.5.6 Emergency Power
The pump stations should have access to a backup generator sized to provide power to all
equipment, lights, and other accessories during power interruptions. For NW-LS#1 a backup
generator should be provided within the lift station building. For LS-NW#2, a connection to the
backup generator at the nearby proposed WWTP should be provided. An automatic power transfer
switch should transfer the station’s power supply to the generator during a power disruption and
should return to normal operation when power has been restored. The generator should be
supplied with noise suppression equipment to limit disruption to existing neighbours.
If a diesel generator is selected, the fuel tank should be external to the generator and designed to
meet the requirements of the National Fire Code of Canada, Section 4 and should meet the
requirements of the Contained Tank assembly document ULC-S653.
Due to the size of the building required for the LS-NW#1 pump station valving, instrumentation and
electrical infrastructure, HEJV recommends also locating the backup generator inside the pump
station building. In addition, the site has potential for sea spray and wave action from the nearby
shoreline that could be potentially harmful to the standby generator. The added protection from
the elements would greatly increase the life expectancy of the backup generator.
3.5.7 Controls
All equipment should be controlled through a local control panel mounted in the lift station building.
The local control panel would be a custom panel designed to be integrated into the CBRM SCADA
network. The panel should provide a Hand/Off/Auto control selector to allow for manual control of
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 16
the station. The control system should report remotely to CBRM’s SCADA system including alarm
conditions.
Control instrumentation and equipment should include the following:
®Level sensors/transmitters in the wetwell
®Flow meter/transmitter on the discharge forcemain(s)
®Pressure transmitter
®Surge valve position indication (if required)
®Level alarms
®Unauthorized building access
®Low fuel level
®Pump or generator fault
®Generator operation
The level in the wetwell utilizing ultrasonic level instruments should control the operation of the
pumps. Auxiliary floats will provide high and low level alarms as well as back-up control in the event
of a failure in the ultrasonic equipment.
3.5.8 Security
Security fencing will be installed at the pumping station on the boundary of the land parcel. The
structures will be monitored with an alarm system (via SCADA) to identify unauthorized access.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 17
CHAPTER 4 EXISTING COLLECTION SYSTEM UPGRADES
4.1 Sewage Pump Station Upgrades
HEJV has reviewed the existing New Waterford Collection System for potential upgrades to the
existing sewage pumping stations. There are currently four pump stations in the community of New
Waterford. The age of the existing stations is on average 24 years old. The New Waterford WWTP
has been classified as a low priority system and has an implementation deadline of 2040.
Considering that 2040 is 21 years in the future, plans should be made to upgrade each of these
stations as part of the interception work to be completed in the community. Due to their age, the
necessity to upgrade these stations may occur prior to the implementation of the interceptor sewer
project. Therefore, the condition of each station should be verified at the time of detailed design to
determine if an upgrade of the existing station is required.
4.2 Asset Condition Assessment Program
To get a better sense of the condition of the existing New Waterford sewage collection system, HEJV
recommends completing a sewage collection system asset condition assessment program in the
community. The program would carry out an investigation involving two components:
®Visual inspection and assessment of all manholes in the collection system
®Video inspection of 20% of all sewers in the system
The program should be completed with the issuance of a Collection System Asset Condition
Assessment Report that would summarize the condition of the various assets inspected and include
opinions of probable costs for required upgrades.
4.3 Sewer Separation Measures
As indicated during the flow metering program, there appears to be very high amounts of
extraneous water entering the collection system, particularly in the NW#1 sewershed. CBRM should
consider completing further sewer separation investigation efforts in New Waterford. The program
would review catch basins that are currently connected or possibly connected to existing sanitary
sewers. The program should also include the costing of the installation of new storm sewers to
disconnect catch basins from the existing sanitary sewer.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 18
CHAPTER 5 PIPE MATERIAL SELECTION AND DESIGN
5.1 Pipe Material
Four pipe materials (Ductile Iron, HDPE, PVC, and Reinforced Concrete) were considered for this
project and were evaluated against various factors. Ductile Iron, HDPE and PVC were reviewed for a
suitable forcemain material for the project. PVC and Reinforced Concrete were reviewed against
each other for a suitable gravity pipe material. A summary of the advantages and disadvantages of
the different materials is presented in Table 5-1.
Table 5-1 Comparison of Pipe Materials
Pipe Material Advantages Disadvantages
Ductile Iron
·Is forgiving with regard to problems
caused by improper bedding
·Thinnest wall, greatest strength
·Standard testing method
·CBRM staff and contractors are
familiar with installation of DI
forcemains
·Pipe, and fittings are susceptible to corrosion
·High weight
·Installation cost is high
HDPE
·Excellent corrosion resistance of pipe
·Long laying lengths (where practical)
·Relatively easy to handle
·Requires good bedding
·Requires butt fusing
·Careful handling is required due to abrasion
·Long distances of open trench
·Not designed for vacuum conditions
·Installation cost is high if long lay lengths are not
possible
PVC
·CBRM standard
·Excellent corrosion resistance of pipe
·Standard testing method
·Light weight
·High impact strength
·CBRM staff and contractors are
familiar with installation of PVC
forcemains
·Cost competitive
·Requires good bedding
·Must be handled carefully in freezing conditions
·Fittings are susceptible to corrosion
Reinforced
Concrete
·High strength
·Standard testing method
·CBRM staff and contractors are
familiar with installation
·Heavy – harder to handle
·Susceptible to attached by H2S and acids when
not coated
·Requires careful installation to avoid cracking
·Short laying lengths
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 19
Based on the above comparison, HEJV recommends that the gravity sewer be PVC. As there will be a
section of forcemain to be installed via directional drilling, HEJV recommends that the forcemain
piping for the New Waterford interceptor sewer be HDPE.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 20
CHAPTER 6 LAND AND EASEMENT REQUIREMENTS
HEJV has reviewed the requirements for land acquisition and easements. Most of the proposed
system, gravity sewers and forcemains, will be constructed on land owned by Public Works and
Government Services Canada. However, an easement will be required for a section of forcemain on
private land, and a portion of the WWTP will be located on two parcels of private land.
6.1 Lift Station Sites
HEJV proposes that the land parcel for the LS-NW#1 site be purchased due to the development
being a permanent above ground structure requiring regular access from CBRM staff. HEJV
considers easements to be an acceptable option to both CBRM and residential land owners for the
construction and maintenance of the interceptor linear infrastructure. The parcel of land associated
with LS-NW#2 would be part of the overall WWTP development, and would be included with the
costs associated with land acquisition for the WWTP site.
Find below a summary of the required land acquisitions that should be undertaken to permit the
installation of the required LS-NW#1 infrastructure. The table below lists the PID, property owner,
assessed value, size of parcel required and whether or not HEJV recommends purchasing the entire
lot. In some circumstances, due to the size of the lot, it might make more sense to purchase the
entire lot from the existing land owner, versus negotiating a piece that would considerably limit the
development on the remaining site.
Table 6-1 Lift Station Land Acquisition Details
PID Property
Owner Assessed Value Description Size Required Purchase Entire
Lot (Y/N)
15482730 PWGSC $1,900 PS Site N/A Y
15006943 PWGSC $48,700 Access Road
10mx20m
(irregular
shape)
N
6.2 WWTP Site
As discussed in Section 3.3, the WWTP and LS-NW#2 lift station will be located on a parcel of land
owned by Public Works and Government Services Canada (PWGSC). Given that the same parcel of
land owned by PWGSC encompasses the WWTP Site #1 and Site #2 and the two proposed lift
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 21
stations, it is recommended that CBRM purchase the entire parcel rather than a portion of the
property. This would allow some flexibility in siting the WWTP in future.
Table 6-2 WWTP Land Acquisition Details
PID Property
Owner Assessed Value Description Size Required Purchase Entire
Lot (Y/N)
15483100 PWGSC $8,600 WWTP Site N/A Y
15006935 David Wilson $12,000 WWTP Site N/A Y
15484108 John Wilson
Sandra Wilson $85,300 WWTP Site N/A Y
15484090
David Allan
Wilson
Lori Anne
Wilson
$279,400 WWTP Site N/A Y
6.3 Linear Infrastructure
The installation of linear infrastructure will require an easement through PID 15483092 and
15483100. The remaining linear infrastructure will be installed within the PWGSC parcel of land that
HEJV has recommended for purchase. Details on the required easement area is as follows:
Table 6-3 Linear Infrastructure Land Acquisition Details
PID Property
Owner Assessed Value Description Size Required Purchase Entire
Lot (Y/N)
15483092 Collieries
Parish $87,100 Forcemain
10m (Construction)
6m (Final)
X 75m length N
15483100 PWGSC $8,600 Forcemain &
Gravity
N/A Y
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 22
CHAPTER 7 SITE SPECIFIC CONSTRAINTS
During the preliminary design of the interceptor system, HEJV has reviewed the site for the lift
station and pipe routing for potential constraints. HEJV reviewed construction constraints,
environmental constraints, access requirements and power supply requirements for the proposed
interceptor infrastructure. A summary of HEJV’s review follows in the next sections of the Design
Brief. As part of this preliminary design project, HEJV recommended an archaeological assessment
be undertaken to review the proposed WWTP site and interception route for culturally sensitive
lands. CBRM agreed with this recommendation and a review was completed by Davis MacIntyre &
Associated Ltd. Refer to the report “CBRM WWTP Project: New Waterford Archaeological Resource
Impact Assessment” dated December 14, 2018, which was submitted to CBRM under a separate
cover.
7.1 Construction Constraints
HEJV has reviewed the preliminary design of the interceptor system from a construction constraints
perspective. One construction constraint exists at the proposed location for LS-NW#1. The site is in
close proximity to the shoreline. The site for the lift station was selected taking sea level rise and
increasing storm surge events into consideration. The detailed design of the station will need to
confirm that the grade at the lift station site is suitably selected for such future conditions.
7.2 Environmental Constraints
The proposed pipe routing will cross a brook between the proposed locations of the lift station and
the WWTP. The brook crossing (Station 0+160) has been proposed to be completed by directional
drilling which will prevent the need for a temporary stream diversion and a work in the dry program.
A wet lands is indicated on the provincial mapping for the Barrachois area, approximately below the
2m contour to the east of the WWTP site. HEJV recommends that this wetland be delineated in the
field by a qualified wetland delineator prior to the detailed design of the WWTP.
7.3 Access Requirements
Access to the LS-NW#1 site should be fairly straight forward, as it is adjacent to Beach Street. A
driveway should be extended from Beach Street. The perimeter of the pump station site will be
fenced so an entrance gate would also be required. Near Beach Street a gate should be provided to
limit access to the site driveway.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 23
The WWTP location is adjacent to Mahon Street and will require an access driveway to be
constructed along with an entrance gate for security purposes. Access requirements for the WWTP
site will be further detailed in the New Waterford WWTP Pre-Design Brief. Access to the LS-NW#2
would be accommodated through the WWTP site.
7.4 Power Supply Requirements
Three phase power will be required for each of the pump stations. For LS-NW#1, three phase power
is currently accessible on Hincey Avenue. Approximately 410m of new overhead conductors and a
series of utility poles will be required. For LS-NW#2, three phase power is accessible on Ellsworth
Avenue. Three phase power will need to be extended an approximate distance of 600m, along
Mahon Street to the site for the pump station and WWTP site.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 24
CHAPTER 8 OPINION OF PROBABLE COSTS
8.1 Opinion of Probable Costs
An opinion of Probable Construction Costs has been completed for the project. A detailed
breakdown of the estimate has been provided in Appendix C. The estimate is made up of the linear
infrastructure, associated land acquisition costs and lift stations required to collect and convey
sanitary sewer in New Waterford to the proposed WWTP. For land acquisition costs, HEJV has used
a ratio of the amount of land that is affected by the required easement/property acquisition
multiplied by the assessed value of the entire lot. The Opinion of Probable Construction Costs for
the interceptor sewer for New Waterford is $2,865,530. This estimate is considered to be Class ‘C’,
accurate within plus or minus 30%.
8.2 Opinion of Operating Costs
HEJV completed an Opinion of Operating Costs for the interceptor system using data provided by
CBRM for typical annual operating costs of their existing submersible lift stations, typical employee
salaries, Nova Scotia Power rates, and experience from similar stations for general maintenance. The
opinion of operating costing includes general lift station maintenance costs, general linear
maintenance costs, employee operation and maintenance costs, electrical operational costs and
backup generator operation.
Table 8-1 Annual Operations and Maintenance Cost
The general station maintenance cost presented above includes pump repairs (impellers, bearings,
seals), minor building maintenance (painting, siding repairs, roof repairs), electrical repairs and
instrumentation repairs and servicing.
Item Anticipated Cost/yr
General Linear Maintenance Cost $500/yr
General Lift Station Maintenance Cost $7,000/yr
Employee O&M Cost $7,000/yr
Electrical Operational Cost $27,000/yr
Backup Generator O&M Cost $6,300/yr
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 25
The general linear maintenance cost for the interceptor system has been estimated to be $500 per
year in 2019 dollars. This includes flushing, inspection, and refurbishment of structures along the
linear portion of the collection system.
Employee O&M costs were averaged from data provided by CBRM. It was determined that staffing
to maintain their existing lift stations requires an average of 100 hours of effort per submersible lift
station per year.
For the electrical operation cost, HEJV assumed the lift station buildings would require heat for 5
months of the year. Basic electrical loads for instrumentation were assumed. Electrical demand from
the pumping system was determined based on the yearly average flow of the station.
Backup generator operation and maintenance costs assumed that a diesel backup generator would
be utilized. The costs include an annual diesel fuel cost assuming that the generator is run for four
hours each month, as well as annual maintenance for the generator (change of filters and oil,
inspection of the generator, and load bank testing).
8.3 Opinion of Existing Collection System Upgrades and Assessment Costs
Opinions of probable cost have been provided to complete the work that was discussed in Chapter
4. For sewage pumping stations, the opinion of probable cost includes a full retrofit of each of the
existing stations noted in Chapter 4 including new pumps, controls and backup power generation.
The need to upgrade these stations should be verified at detailed design, as discussed in Chapter 4.
Lift station upgrade costs are presented in Table 8-2. HEJV has provided an allowance of 12% on the
cost of construction for engineering and 25% for contingency allowance.
An opinion of probable costs has been provided for the collection system asset condition
assessment program described in Chapter 4. These costs include the video inspection and flushing of
20% of the existing sanitary sewer network, visual inspection of manholes, traffic control and the
preparation of a collection system asset condition assessment report.
For sewer separation measures, budgetary pricing has been calculated by reviewing recent costs of
sewer separation measures in CBRM involving installation of new storm sewers to remove
extraneous flow from existing sanitary sewers. These costs have been translated into a cost per
lineal meter of sewer main. This unit rate was then applied to the overall collection system. The cost
also includes an allowance of 10% on the cost of construction for engineering and 25% for
contingency allowance.
Estimates of costs for upgrades to and assessment of the existing collection system as outlined in
Table 8-2 are considered to be Class ‘D’, accurate to within plus or minus 45%.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 26
Table 8-2 Estimated Existing Collection System Upgrade and Assessment Costs
8.4 Opinion of Annual Capital Replacement Fund Contributions
The CBRM wishes to create a Capital Replacement Fund to which annual contributions would be
made to prepare for replacement of the assets at the end of their useful life. The calculation of
annual contributions to this fund involves consideration of such factors as the type of asset, the
asset value, the expected useful life of the asset, and the corresponding annual depreciation rate for
the asset. In consideration of these factors,Table 8-3 provides an estimation of the annual
contributions to a capital replacement fund for the proposed new wastewater collection and
interception infrastructure.
Table 8-3 Estimated Annual Capital Replacement Fund Contributions
Description of Asset Asset Value
Asset Useful
Life
Expectancy
(Years)
Annual
Depreciation
Rate (%)
Annual Capital
Replacement
Fund Contribution
Linear Assets (Piping, Manholes and Other)$524,030 75 1.3%$6,812
Pump Station Structures (Concrete
Chambers, etc.)$874,280 50 2.0%$17,486
Pump Station Equipment (Mechanical /
Electrical)$715,320 20 5.0%$35,766
Subtotal $2,113,630 --$60,064
Contingency Allowance (Subtotal x 25%):$15,016
Engineering (Subtotal x 10%):$6,006
Opinion of Probable Annual Capital Replacement Fund Contribution:$81,086
Note:
Annual contribuƟons do not account for annual inflaƟon.
Item Cost
Sewage Pump Station Upgrades
Pump Station Infrastructure (controls, pumps, etc.)$841,000
Backup Power Generation $211,000
Engineering (12%)$126,000
Contingency (25%)$263,000
Total $1,441,000
Collection System Asset Condition Assessment Program
Condition Assessment of Manholes based on 825 MH’s $155,000
Condition Assessment of Sewer Mains based on 14 km’s of infrastructure $125,000
Total $280,000
Sewer Separation Measures
Separation based on 70km’s of sewer @ $45,000/km $3,150,000
Engineering (10%)$315,000
Contingency (25%)$788,000
Total $4,253,000
Total Estimated Existing Collection System Upgrade and Assessment Costs $5,974,000
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 27
CHAPTER 9 REFERENCES
Environment Canada (2006) –Atlantic Canada Wastewater Gidelines Manual for Collection,
Treatment and Disposal.
Harbour Engineering Inc. (2011).Cape Breton Regional Municipality Wastewater Strategy 2009.
Nova Scotia Environment (2018).Environment Act.
Nova Scotia Utility and Review Board (2013).Water Utility Accounting and Reporting Handbook.
UMA Engineering Ltd. (1994). Industrial Cape Breton Wastewater Characterization Programme –
Phase II.
Water Environment Federation (2009),Design of Wastewater and Stormwater Pumping Stations.
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 28
APPENDIX A
Drawings
NW2
NW1
NEW
W
A
T
E
R
F
O
R
D
H
I
G
H
W
A
Y
NEW W
A
T
E
R
F
O
R
D
H
I
G
H
W
A
Y
NW2
OL
I
V
E
S
T
ELLSWORTH AVE
MA
H
O
N
S
T
MINER AVE
KI
N
G
S
T
SM
I
T
H
S
T
PLUMMER AVE
LIN
G
S
T
PLUMM
E
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A
V
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EL
L
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W
O
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H
A
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ELLSWORTH AVE
LIN
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S
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MA
H
O
N
S
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EMERALD ST
DUGGAN AVE
UN
I
O
N
H
I
G
H
W
A
Y
EMERALD ST
KI
N
G
S
T
ROA
C
H
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S
R
D
WILSON AVEWILSON AVE WILSON AVE
EMERALD ST
MAY ST
PA
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C
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UNI
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N
H
I
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H
W
A
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NICK
L
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W
O
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D
D
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MINER AVE
HINCHEY AVE
PLUMMER AVE
KI
N
G
S
T
OC
E
A
N
V
I
E
W
B
L
V
D
1
ENVIRONMENTAL RISK ASSESSMENTS
& PRELIMINARY DESIGN
CDL
CDL JRS
JRS 18-7116
1:8000
MARCH 2019
HA
R
B
O
U
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N
G
I
N
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E
R
I
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J
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2
7
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,
S
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N
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,
N
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,
B
1
P
1
C
6
A
B
ISSUED FOR DRAFT BREIF
ISSUED FOR FINAL BRIEF
12/20/18
03/06/19
JRS
JRS
NEW WATERFORD INTERCEPTOR
EXISTING PLAN
DATE
DESIGN
DRAWN
PROJECT NO.
SHEET NO.
No.DATE BYISSUED FOR
written permission from Dillon Consulting Limited.
than those intended at the time of its preparation without prior
Do not scale dimensions from drawing.
Report any discrepancies to Dillon Consulting Limited.
Verify elevations and/or dimensions on drawing prior to use.
Conditions of Use
REVIEWED BY
CHECKED BY
Do not modify drawing, re-use it, or use it for purposes other
SCALEj o i n t v e n t u r e
PLAN
1:2500
2000
1:8,000SCALE METRES
200
15483092
(COLLERIES
PARISH)
NW2
NW1
NW2
O
L
I
V
E
S
T
ELLSW
O
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T
H
A
V
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M
A
H
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N
S
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MINER
A
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I
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HINCH
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A
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PLUMM
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K
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PROPOSED 400mmØ FORCEMAIN
50m OF 400mmØ FORCEMAIN
TO BE DIRECTIONAL DRILLED
PROPOSED GRAVITY SEWER
CONNECTION (750mmØ)
15482730
(PUBLIC WORKS AND GOVERNMENT
SERVICES CANADA)15484108
(JOHN/SANDRA WILSON)
OUTLINE OF
PROPERTY
REQUIRING
EASEMENT
OUTLINE OF PROPERTY
REQUIRING ACQUISITION
15483100
(PUBLIC WORKS AND GOVERNMENT
SERVICES CANADA)
15006935
(DAVID ALLEN WILSON)
LS-NW1
PROPOSED GRAVITY SEWER
CONNECTIONS (2 - 600mmØ)
PROPOSED CSO OVERFLOW
CONNECTION (750mmØ)
PROPOSED GRAVITY SEWER
CONNECTIONS ( 2 REQ'D - 750mmØ)
CSO-1
PROPOSED 150mmØ FORCEMAIN
LS-NW2
CSO-2
15484090
(DAVID ALLAN WILSON)
PROPOSED
WWTP SITE
PROPOSED 400mmØ FORCEMAIN
EXISTING GROUND PROFILE
PROPOSED COMBINATION
AIR/VACUUM RELEASE VALVE
15
0
m
m
Ø
L
S
-
N
W
2
CO
N
N
E
C
T
I
O
N
WW
T
P
EXISTING 600mmØ
GRAVITY SEWER
EXISTING 600mmØ
GRAVITY SEWER
2
ENVIRONMENTAL RISK ASSESSMENTS
& PRELIMINARY DESIGN
CDL
CDL JRS
JRS 18-7116
1:2500
MARCH 2019
HA
R
B
O
U
R
E
N
G
I
N
E
E
R
I
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,
N
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,
B
1
P
1
C
6
A
B
ISSUED FOR DRAFT BRIEF
ISSUED FOR FINAL BRIEF
10/15/18
03/06/19
JRS
JRS
NEW WATERFORD INTERCEPTOR
PLAN/PROFILE
DATE
DESIGN
DRAWN
PROJECT NO.
SHEET NO.
No.DATE BYISSUED FOR
written permission from Dillon Consulting Limited.
than those intended at the time of its preparation without prior
Do not scale dimensions from drawing.
Report any discrepancies to Dillon Consulting Limited.
Verify elevations and/or dimensions on drawing prior to use.
Conditions of Use
REVIEWED BY
CHECKED BY
Do not modify drawing, re-use it, or use it for purposes other
SCALEj o i n t v e n t u r e
PLAN
1:2500
PROFILE
HOR:1:2500\VERT:1:500
0 50
1:2,500SCALE METRES
50
3
ENVIRONMENTAL RISK ASSESSMENTS
& PRELIMINARY DESIGN
AMA/JRS DFM
DFM 18-7116
1:500
APRIL 2019
HA
R
B
O
U
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N
G
I
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N
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B
1
P
1
C
6
A ISSUED FOR DRAFT BRIEF 04/15/19 JRS
BARRACHOIS AREA EROSION AND
HUB SEAM MINE FEATURES
DATE
DESIGN
DRAWN
PROJECT NO.
SHEET NO.
No.DATE BYISSUED FOR
written permission from Dillon Consulting Limited.
than those intended at the time of its preparation without prior
Do not scale dimensions from drawing.
Report any discrepancies to Dillon Consulting Limited.
Verify elevations and/or dimensions on drawing prior to use.
Conditions of Use
REVIEWED BY
CHECKED BY
Do not modify drawing, re-use it, or use it for purposes other
SCALEj o i n t v e n t u r e
0 10
1:500SCALE METRES
10
1
5
___
1
5
___
FLUSH MOUNT ALUMINUM
HATCH C/W SAFETY GATE.
CLEAR OPENING 900x1500
100Ø VENT AND 150Ø CAP
150Ø FLOW METER ON
VERTICAL (TYP.)
AIR RELEASE VALVE (TYP.)
WATER SERVICE
150Ø CHECK VALVE AND
PLUG VALVE ON VERTICAL (TYP.2)
CONCRETE SLAB
DAVIT
SOCKET
ELECTRICAL ROOMPROCESS ROOM
21692679
j o i n t v e n t u r e
DATE
DESIGN
DRAWN
PROJECT NO.
SHEET NO.
No.DATE BYISSUED FOR
written permission from Dillon Consulting Limited.
than those intended at the time of its preparation without prior
Do not scale dimensions from drawing.
Report any discrepancies to Dillon Consulting Limited.Verify elevations and/or dimensions on drawing prior to use.
Conditions of Use
REVIEWED BY
CHECKED BY
Do not modify drawing, re-use it, or use it for purposes other
SCALE
FIL
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N
A
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:
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:
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NTSAISSUED FOR DRAFT DESIGN BRIEF 04/09/19 JRS
18-7116OF 7 FUTURE WASTEWATER TREATMENT SYSTEMS IN CBRM
ENVIRONMENTAL RISK ASSESSMENTS & PRELIMINARY DESIGN
APRIL 2019
SMZ ASW
4
ASW MAB
PLAN
NEW WATERFORD DUPLEX LIFT STATION
SCALE:SCALE:NTS
WET WELL - ABOVE GRADE
SCALE:SCALE:
MODEL VIEW I
150Ø FLOW
METER
150Ø SWING CHECK VALVE (TYP.2)
150Ø PLUG VALVE (TYP.3)
FORCEMAIN
AIR RELEASE VALVE (TYP.)
SS PIPE FROM PUMPS
FLUSH MOUNT ALUMINUM
HATCH C/W SAFETY GATE.
CLEAR OPENING 900x1500
PVC INLET PIPE
INLET BAFFLE
FORCEMAIN
100Ø VENT AND 150Ø VENT CAP
j o i n t v e n t u r e
DATE
DESIGN
DRAWN
PROJECT NO.
SHEET NO.
No.DATE BYISSUED FOR
written permission from Dillon Consulting Limited.
than those intended at the time of its preparation without prior
Do not scale dimensions from drawing.
Report any discrepancies to Dillon Consulting Limited.Verify elevations and/or dimensions on drawing prior to use.
Conditions of Use
REVIEWED BY
CHECKED BY
Do not modify drawing, re-use it, or use it for purposes other
SCALE
FIL
E
N
A
M
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:
C
:
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B
NTSAISSUED FOR DRAFT DESIGN BRIEF 04/09/19 JRS
18-7116OF 7 FUTURE WASTEWATER TREATMENT SYSTEMS IN CBRM
ENVIRONMENTAL RISK ASSESSMENTS & PRELIMINARY DESIGN
APRIL 2019
SMZ ASW
5
ASW MAB
SECTIONS
NEW WATERFORD DUPLEX LIFT STATION
SCALE:SCALE:NTS
SECTION 1
SCALE:SCALE:NTS
WET WELL - BELOW GRADE
400Ø FLOW METER (TYP.)
250Ø CHECK VALVE
1
7
___
1
7
___
2
7
___2
7
___
ELECTRICAL ROOM
250Ø PLUG VALVE
AIR RELEASE VALVE TO BE
VENTED TO WET WELL (TYP)
FO
R
C
E
M
A
I
N
GENERATOR ROOM
80
8
3
21
2
1
27
0
5
32
5
7
8180
54472736
2900
50
0
400Ø PROCESS PIPING
250Ø PROCESS PIPING
400Ø PLUG
VALVE
20
0
0
80
0
1260 1260
1
7
___
1
7
___
WET WELL FOOTING
150Ø VENT AND 200Ø CAP
INLET BAFFLE
24
0
0
3600
FLUSH MOUNT ALUMINUM
HATCH C/W WITH SAFETY GRATE
1200Ø SEWER INLET
SLUICE GATE
1800 x 1800 MANHOLE
1200Ø SEWER INLET
OVERFLOW
PLAN
3D MODEL
j o i n t v e n t u r e
DATE
DESIGN
DRAWN
PROJECT NO.
SHEET NO.
No.DATE BYISSUED FOR
written permission from Dillon Consulting Limited.
than those intended at the time of its preparation without prior
Do not scale dimensions from drawing.
Report any discrepancies to Dillon Consulting Limited.Verify elevations and/or dimensions on drawing prior to use.
Conditions of Use
REVIEWED BY
CHECKED BY
Do not modify drawing, re-use it, or use it for purposes other
SCALE
FIL
E
N
A
M
E
:
C
:
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N.T.SAISSUED FOR DRAFT DESIGN BRIEF 04/09/19 JRS
18-7116OF 7 FUTURE WASTEWATER TREATMENT SYSTEMS IN CBRM
ENVIRONMENTAL RISK ASSESSMENTS & PRELIMINARY DESIGN
APRIL 2019
MSR ASW
6
ASW MAB
PLAN
NEW WATERFORD TRIPLEX PUMP STATIONS
WET WELL PLAN
250Ø PIPE
PUMP GUIDE BARS (TYP.)
DISCHARGE PIPE SUPPORTS (TYP.)
FORCEMAIN
400Ø FLOW
METER (TYP.)
AIR RELEASE
VALVE (TYP.3)
PUMP LIFTING CHAIN TO EXTEND
AND ATTACH TO CHAMBER LID (TYP.3)
WET WELL BENCHING
CONCRETE
MUD SLABCLEAR STONE
BEDDING (TYP.)
PRESSURE
TRANSDUCER
(TYP.)
MULTITRODE
LIQUID
LEVEL SENSOR
(TYP.)TIE DOWN ANCHOR SYSTEM TO RESIST BUOYANT UPLIFT
PRESSURE.
PRECAST CONCRETE BASE, RISERS AND COVER (TYP.)
HORIZONTAL
LEVEL
REGULATOR
HANGER
BASE SLAB TO EXTEND
DI PVCTRANSITION COUPLING
AT 1m OUTSIDE FOUNDATION (TYP.)
400Ø
AIR RELEASE
VALVE
INLET BAFFLE.
SEE PLAN
INLET
500
400Ø
40
0
Ø
250x400 REDUCER
25
0
Ø
250Ø
400Ø PLUG
VALVE
2000 800
250Ø PLUG VALVE
250Ø CHECK VALVE
250Ø CHECK VALVE AND
250Ø PLUG VALVE ON
HORIZONTAL. (TYP.3)
SEE PLAN.
250Ø PIPE
PRECAST CONCRETE BASE,
RISERS AND COVER (TYP.)
PUMP (TYP.)
WET WELL BENCHING
NOTE: BAFFLE WALL
NOT SHOWN FOR
CLARITY. SEE PLAN.
AIR RELEASE
VALVE (TYP.)
250Ø PIPE
j o i n t v e n t u r e
DATE
DESIGN
DRAWN
PROJECT NO.
SHEET NO.
No.DATE BYISSUED FOR
written permission from Dillon Consulting Limited.
than those intended at the time of its preparation without prior
Do not scale dimensions from drawing.
Report any discrepancies to Dillon Consulting Limited.
Verify elevations and/or dimensions on drawing prior to use.
Conditions of Use
REVIEWED BY
CHECKED BY
Do not modify drawing, re-use it, or use it for purposes other
SCALE
FI
L
E
N
A
M
E
:
C
:
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B
N.T.SAISSUED FOR DRAFT DESIGN BRIEF 04/09/19 JRS
18-7116OF 7 FUTURE WASTEWATER TREATMENT SYSTEMS IN CBRM
ENVIRONMENTAL RISK ASSESSMENTS & PRELIMINARY DESIGN
APRIL 2019
MSR ASW
7
ASW MAB
SECTIONS
NEW WATERFORD TRIPLEX PUMP STATIONS
SECTION 1 SECTION 2
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 29
APPENDIX B
Flow Master Reports
Project Description
Friction Method Manning Formula
Solve For Discharge
Input Data
Roughness Coefficient 0.015
Channel Slope 0.06000 %
Normal Depth 0.75 m
Diameter 0.75 m
Results
Discharge 236.34 L/s
Flow Area 0.44 m²
Wetted Perimeter 2.36 m
Hydraulic Radius 0.19 m
Top Width 0.00 m
Critical Depth 0.29 m
Percent Full 100.0 %
Critical Slope 0.56557 %
Velocity 0.53 m/s
Velocity Head 0.01 m
Specific Energy 0.76 m
Froude Number 0.00
Maximum Discharge 0.25 m³/s
Discharge Full 236.34 L/s
Slope Full 0.06000 %
Flow Type SubCritical
GVF Input Data
Downstream Depth 0.00 m
Length 0.00 m
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 m
Profile Description
Profile Headloss 0.00 m
Average End Depth Over Rise 0.00 %
Normal Depth Over Rise 100.00 %
Downstream Velocity Infinity m/s
Interceptor Connection 750mm
2019-04-25 3:22:37 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of1Page
GVF Output Data
Upstream Velocity Infinity m/s
Normal Depth 0.75 m
Critical Depth 0.29 m
Channel Slope 0.06000 %
Critical Slope 0.56557 %
Interceptor Connection 750mm
2019-04-25 3:22:37 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of2Page
Project Description
Friction Method Manning Formula
Solve For Discharge
Input Data
Roughness Coefficient 0.015
Channel Slope 0.08000 %
Normal Depth 0.60 m
Diameter 0.60 m
Results
Discharge 150.51 L/s
Flow Area 0.28 m²
Wetted Perimeter 1.88 m
Hydraulic Radius 0.15 m
Top Width 0.00 m
Critical Depth 0.25 m
Percent Full 100.0 %
Critical Slope 0.61560 %
Velocity 0.53 m/s
Velocity Head 0.01 m
Specific Energy 0.61 m
Froude Number 0.00
Maximum Discharge 0.16 m³/s
Discharge Full 150.51 L/s
Slope Full 0.08000 %
Flow Type SubCritical
GVF Input Data
Downstream Depth 0.00 m
Length 0.00 m
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 m
Profile Description
Profile Headloss 0.00 m
Average End Depth Over Rise 0.00 %
Normal Depth Over Rise 100.00 %
Downstream Velocity Infinity m/s
CSO-1 To LS1 600mm
2019-04-25 3:31:40 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of1Page
GVF Output Data
Upstream Velocity Infinity m/s
Normal Depth 0.60 m
Critical Depth 0.25 m
Channel Slope 0.08000 %
Critical Slope 0.61560 %
CSO-1 To LS1 600mm
2019-04-25 3:31:40 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of2Page
Project Description
Friction Method Manning Formula
Solve For Discharge
Input Data
Roughness Coefficient 0.015
Channel Slope 0.06000 %
Normal Depth 0.75 m
Diameter 0.75 m
Results
Discharge 236.34 L/s
Flow Area 0.44 m²
Wetted Perimeter 2.36 m
Hydraulic Radius 0.19 m
Top Width 0.00 m
Critical Depth 0.29 m
Percent Full 100.0 %
Critical Slope 0.56557 %
Velocity 0.53 m/s
Velocity Head 0.01 m
Specific Energy 0.76 m
Froude Number 0.00
Maximum Discharge 0.25 m³/s
Discharge Full 236.34 L/s
Slope Full 0.06000 %
Flow Type SubCritical
GVF Input Data
Downstream Depth 0.00 m
Length 0.00 m
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 m
Profile Description
Profile Headloss 0.00 m
Average End Depth Over Rise 0.00 %
Normal Depth Over Rise 100.00 %
Downstream Velocity Infinity m/s
CSO-1 Overflow To NW1 750mm
2019-04-25 4:05:28 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of1Page
GVF Output Data
Upstream Velocity Infinity m/s
Normal Depth 0.75 m
Critical Depth 0.29 m
Channel Slope 0.06000 %
Critical Slope 0.56557 %
CSO-1 Overflow To NW1 750mm
2019-04-25 4:05:28 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of2Page
Project Description
Friction Method Manning Formula
Solve For Discharge
Input Data
Roughness Coefficient 0.015
Channel Slope 0.08000 %
Normal Depth 0.60 m
Diameter 0.60 m
Results
Discharge 150.51 L/s
Flow Area 0.28 m²
Wetted Perimeter 1.88 m
Hydraulic Radius 0.15 m
Top Width 0.00 m
Critical Depth 0.25 m
Percent Full 100.0 %
Critical Slope 0.61560 %
Velocity 0.53 m/s
Velocity Head 0.01 m
Specific Energy 0.61 m
Froude Number 0.00
Maximum Discharge 0.16 m³/s
Discharge Full 150.51 L/s
Slope Full 0.08000 %
Flow Type SubCritical
GVF Input Data
Downstream Depth 0.00 m
Length 0.00 m
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 m
Profile Description
Profile Headloss 0.00 m
Average End Depth Over Rise 0.00 %
Normal Depth Over Rise 100.00 %
Downstream Velocity Infinity m/s
Interceptor Connection 600mm
2019-04-25 3:25:56 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of1Page
GVF Output Data
Upstream Velocity Infinity m/s
Normal Depth 0.60 m
Critical Depth 0.25 m
Channel Slope 0.08000 %
Critical Slope 0.61560 %
Interceptor Connection 600mm
2019-04-25 3:25:56 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of2Page
Project Description
Friction Method Manning Formula
Solve For Discharge
Input Data
Roughness Coefficient 0.015
Channel Slope 0.22000 %
Normal Depth 0.30 m
Diameter 0.30 m
Results
Discharge 39.31 L/s
Flow Area 0.07 m²
Wetted Perimeter 0.94 m
Hydraulic Radius 0.08 m
Top Width 0.00 m
Critical Depth 0.15 m
Percent Full 100.0 %
Critical Slope 0.82791 %
Velocity 0.56 m/s
Velocity Head 0.02 m
Specific Energy 0.32 m
Froude Number 0.00
Maximum Discharge 0.04 m³/s
Discharge Full 39.31 L/s
Slope Full 0.22000 %
Flow Type SubCritical
GVF Input Data
Downstream Depth 0.00 m
Length 0.00 m
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 m
Profile Description
Profile Headloss 0.00 m
Average End Depth Over Rise 0.00 %
Normal Depth Over Rise 100.00 %
Downstream Velocity Infinity m/s
CSO-2 To LS2 300mm
2019-04-25 3:30:42 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of1Page
GVF Output Data
Upstream Velocity Infinity m/s
Normal Depth 0.30 m
Critical Depth 0.15 m
Channel Slope 0.22000 %
Critical Slope 0.82791 %
CSO-2 To LS2 300mm
2019-04-25 3:30:42 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of2Page
Project Description
Friction Method Manning Formula
Solve For Discharge
Input Data
Roughness Coefficient 0.015
Channel Slope 0.08000 %
Normal Depth 0.60 m
Diameter 0.60 m
Results
Discharge 150.51 L/s
Flow Area 0.28 m²
Wetted Perimeter 1.88 m
Hydraulic Radius 0.15 m
Top Width 0.00 m
Critical Depth 0.25 m
Percent Full 100.0 %
Critical Slope 0.61560 %
Velocity 0.53 m/s
Velocity Head 0.01 m
Specific Energy 0.61 m
Froude Number 0.00
Maximum Discharge 0.16 m³/s
Discharge Full 150.51 L/s
Slope Full 0.08000 %
Flow Type SubCritical
GVF Input Data
Downstream Depth 0.00 m
Length 0.00 m
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 m
Profile Description
Profile Headloss 0.00 m
Average End Depth Over Rise 0.00 %
Normal Depth Over Rise 100.00 %
Downstream Velocity Infinity m/s
CSO-2 Overflow To NW2 600mm
2019-04-25 4:04:02 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of1Page
GVF Output Data
Upstream Velocity Infinity m/s
Normal Depth 0.60 m
Critical Depth 0.25 m
Channel Slope 0.08000 %
Critical Slope 0.61560 %
CSO-2 Overflow To NW2 600mm
2019-04-25 4:04:02 PM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of2Page
Project Description
Friction Method Hazen-Williams Formula
Solve For Pressure at 2
Input Data
Pressure 1 0.00 psi
Elevation 1 -0.92 m
Elevation 2 2.11 m
Length 242.00 m
Roughness Coefficient 120.000
Diameter 0.40 m
Discharge 208.60 L/s
Results
Pressure 2 -6.77 psi
Headloss 1.73 m
Energy Grade 1 -0.78 m
Energy Grade 2 -2.51 m
Hydraulic Grade 1 -0.92 m
Hydraulic Grade 2 -2.65 m
Flow Area 0.13 m²
Wetted Perimeter 1.26 m
Velocity 1.66 m/s
Velocity Head 0.14 m
Friction Slope 0.71682 %
400mm Forcemain
2019-04-26 11:16:53 AM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 1of1Page
Project Description
Friction Method Hazen-Williams Formula
Solve For Pressure at 2
Input Data
Pressure 1 0.00 psi
Elevation 1 -2.00 m
Elevation 2 2.11 m
Length 18.60 m
Roughness Coefficient 120.000
Diameter 0.40 m
Discharge 239.75 L/s
Results
Pressure 2 -6.09 psi
Headloss 0.17 m
Energy Grade 1 -1.81 m
Energy Grade 2 -1.99 m
Hydraulic Grade 1 -2.00 m
Hydraulic Grade 2 -2.17 m
Flow Area 0.13 m²
Wetted Perimeter 1.26 m
Velocity 1.91 m/s
Velocity Head 0.19 m
Friction Slope 0.92757 %
400mm Common Forcemain
2019-04-26 11:15:47 AM
Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 1of1Page
Harbour Engineering Joint Venture New Waterford Collection System Pre-Design Brief 30
APPENDIX C
Opinion of Probable Construction Costs
OPINION OF PROBABLE
COST, CLASS 'C'
Preliminary
Collection Project Manager:D. McLean
and Interception Infrastructure Costs Only Est. by: C. Lund Checked by: D. McLean
New Waterford, NS PROJECT No.:187116 (Dillon)
182402.00 (CBCL)
UPDATED:April 20, 2020
NUMBER UNIT
Linear Infrastructure $324,030.00
300 mm Diameter PVC gravity sewer 10 m $480.00 $4,800.00
600 mm Diameter PVC gravity sewer 40 m $480.00 $19,200.00
750 mm Diameter PVC gravity sewer 60 m $550.00 $33,000.00
150 mm Diameter HDPE forcemain 5 m $300.00 $1,500.00
400 mm Diameter HDPE forcemain 265 m $390.00 $103,350.00
400 mm Diameter Directional Drilled HDPE forcemain 50 m $900.00 $45,000.00
Air Release Chamber 1 each $13,500.00 $13,500.00
1800mm dia. Manhole 2 each $8,500.00 $17,000.00
Connection to Existing Main (c/w 1800mm dia. MH)5 each $15,000.00 $75,000.00
Closed Circuit Televsion Inspection 110 m $8.00 $880.00
Trench Excavation - Rock 120 m3 $60.00 $7,200.00
Trench Excavation - Unsuitable Material 120 m3 $10.00 $1,200.00
Replacement of Unsuitable with Site Material 60 m3 $10.00 $600.00
Replacement of Unsuitable with Pit Run Gravel 60 m3 $30.00 $1,800.00
Beach Street Lift Station $1,022,300.00
Pump Station 1 L.S.$950,000.00 $950,000.00
Site Work 1 L.S.$70,000.00 $70,000.00
Mass Excavation - Rock 25 m3 $60.00 $1,500.00
MassExcavation - Unsuitable Material 25 m3 $10.00 $250.00
Replacement of Unsuitable with Site Material 10 m3 $10.00 $100.00
Replacement of Unsuitable with Pit Run Gravel 15 m3 $30.00 $450.00
Mahon Street Lift Station $567,300.00
Pump Station 1 L.S.$500,000.00 $500,000.00
Site Work 1 L.S.$65,000.00 $65,000.00
Mass Excavation - Rock 25 m3 $60.00 $1,500.00
MassExcavation - Unsuitable Material 25 m3 $10.00 $250.00
Replacement of Unsuitable with Site Material 10 m3 $10.00 $100.00
Replacement of Unsuitable with Pit Run Gravel 15 m3 $30.00 $450.00
Combined Sewer Overflow $200,000.00
Combined Sewer Overflow 2 L.S.$100,000.00 $200,000.00
SUBTOTAL (Construction Cost)$2,113,630.00
Contingency Allowance (Subtotal x 25 %)$529,000.00
Engineering (Subtotal x 10 %)$212,000.00
Land Acquisition $10,900.00
OPINION OF PROBABLE COST (Including Contingency)$2,865,530.00
PREPARED FOR:
Cape Breton
Regional Municipality
EXTENDED TOTALS QUANTITY TOTALUNIT COSTITEM DESCRIPTION
March 27, 2020
HEJV New Waterford Wastewater System Pre‐Design Summary Report Appendices
APPENDIX B
New Waterford Treatment System
Pre‐Design Brief
182402.00 ● Final Brief ● April 2020
Environmental Risk Assessments & Preliminary
Design of Seven Future Wastewater Treatment
Systems in CBRM
New Waterford Wastewater Treatment Plant
Preliminary Design Brief
Prepared by:
Prepared for:
March 2020
New Waterford WW Treatment
System Preliminary Design Brief ‐
Final
April 21, 2020 Darrin McLean Mike Abbott
Dave McKenna Sarah Ensslin
New Waterford WW Treatment
System Preliminary Design Brief May 9, 2019 Darrin McLean Mike Abbott
Dave McKenna Sarah Ensslin
Issue or Revision Date Issued By: Reviewed By: Prepared By:
This document was prepared for the party indicated
herein. The material and information in the
document reflects HE’s opinion and best judgment
based on the information available at the time of
preparation. Any use of this document or reliance
on its content by third parties is the responsibility of
the third party. HE accepts no responsibility for any
damages suffered as a result of third party use of
this document.
182402.00
March 27, 2020
182402.00 NW WWTP PRELIMINARY DESIGN BRIEF DRAFT 20190508 FINAL.DOCX2020‐04‐21/klm
ED: 21/04/2020 11:13:00/PD: 21/04/2020 11:13:00
275 Charlotte Street
Sydney, Nova Scotia
Canada B1P 1C6
Tel: 902‐562‐9880
Fax: 902‐562‐9890
April 21, 2020
Matt Viva, P.Eng.
Manager Wastewater Operations
Cape Breton Regional Municipality (CBRM)
320 Esplanade,
Sydney, NS B1P 7B9
Dear Mr. Viva:
RE: New Waterford Wastewater Treatment Plant Preliminary Design
Enclosed, please find a copy of the Preliminary Design Brief for the New Waterford
Wastewater Treatment Plant (WWTP).
The report presents an evaluation of treatment process alternatives for the New Waterford
WWTP. It also presents a preliminary design based on the recommended SBR treatment
process.
If you have any questions or require clarification on the content presented in the attached
report, please do not hesitate to contact us.
Yours very truly,
Harbour Engineering Joint Venture
Prepared by: Reviewed by:
Sarah Ensslin, M.Sc., P.Eng Mike Abbott, P.Eng., M.Eng.
Process Engineer Manager Process Department
Direct: 902‐421‐7241 (Ext. 2238)
E‐Mail: sensslin@cbcl.ca
Reviewed by:
Dave McKenna, P.Eng., M.Eng.
Associate / Technical Service Lead
Project No: 182402.00 (CBCL)
187116.00 (Dillon)
March 27, 2020
HEJV New Waterford WWTP Preliminary Design Brief i
Contents
CHAPTER 1 Introduction ................................................................................................................ 1
1.1 Introduction ........................................................................................................................ 1
1.2 Background ......................................................................................................................... 1
1.3 Objectives ........................................................................................................................... 1
CHAPTER 2 Existing Conditions ...................................................................................................... 2
2.1 Description of Existing Infrastructure ................................................................................. 2
2.2 Wastewater Flow Characteristics ....................................................................................... 2
2.2.1 Dry Weather Flows ................................................................................................. 3
2.2.2 Average Day Flows .................................................................................................. 4
2.2.3 Peak Day Flow ......................................................................................................... 5
2.2.4 Extraneous Flow Reduction .................................................................................... 6
2.3 Wastewater Quality Characteristics ................................................................................... 6
2.4 Wastewater Loading Analysis ............................................................................................. 7
CHAPTER 3 Basis of Design ............................................................................................................ 9
3.1 Service Area Population ...................................................................................................... 9
3.2 Design Flows and Loads ...................................................................................................... 9
3.3 Effluent Requirements ...................................................................................................... 11
3.4 Design Loads ..................................................................................................................... 12
CHAPTER 4 Treatment Process Alternatives ................................................................................. 13
4.1 Preliminary Treatment ...................................................................................................... 13
4.1.1 Screening .............................................................................................................. 13
4.1.2 Grit Removal ......................................................................................................... 14
4.2 Secondary Treatment ....................................................................................................... 15
4.2.1 Site‐specific Suitability .......................................................................................... 15
4.2.2 Description of Candidate Processes for Secondary Treatment ............................ 16
4.3 Disinfection ....................................................................................................................... 22
4.3.1 CAS/MBBR Effluent Disinfection ........................................................................... 22
4.3.2 SBR Effluent Disinfection ...................................................................................... 23
4.4 Sludge Management ......................................................................................................... 23
4.5 Secondary Treatment Option Evaluation ......................................................................... 24
4.5.1 Capital Cost Estimate ............................................................................................ 24
4.5.2 Operating Cost Estimate ....................................................................................... 24
HEJV New Waterford WWTP Preliminary Design Brief ii
4.5.3 Life Cycle Cost Estimate ........................................................................................ 24
4.5.4 Qualitative Evaluation Factors .............................................................................. 26
4.5.5 Recommended Secondary Treatment Process ..................................................... 26
CHAPTER 5 Preliminary Design .................................................................................................... 27
5.1 Process Description ........................................................................................................... 27
5.2 Unit Process Descriptions ................................................................................................. 27
5.2.1 Preliminary Treatment .......................................................................................... 27
5.2.2 Secondary Treatment ........................................................................................... 28
5.2.3 Disinfection ........................................................................................................... 29
5.2.4 Sludge Management ............................................................................................. 30
5.3 Facilities Description ......................................................................................................... 31
5.3.1 Civil and Site Work ................................................................................................ 32
5.3.2 Odour Control ....................................................................................................... 32
5.3.3 Architectural ......................................................................................................... 32
5.3.4 Mechanical ............................................................................................................ 33
5.3.5 Electrical ................................................................................................................ 33
5.3.6 Lighting ................................................................................................................. 33
5.3.7 Instrumentation .................................................................................................... 33
5.4 Staffing Requirements ...................................................................................................... 36
CHAPTER 6 Project Costs ............................................................................................................. 37
6.1 Opinion of Probable Capital Costs .................................................................................... 37
6.2 Opinion of Annual Operating Costs .................................................................................. 37
6.3 Opinion of Annual Capital Replacement Fund Contributions ........................................... 39
CHAPTER 7 References ................................................................................................................ 40
Appendices
A Flow Meter Data
B Environmental Risk Assessment
C Preliminary Design Drawings
HEJV New Waterford WWTP Preliminary Design Brief 1
CHAPTER 1 INTRODUCTION
1.1 Introduction
Harbour Engineering Joint Venture (HEJV) was retained by the Cape Breton Regional Municipality
(CBRM) to provide engineering services associated with the preliminary design of a wastewater
treatment plant (WWTP) for the community of New Waterford, Nova Scotia as part of the greater
Environmental Risk Assessment and Preliminary Design of 7 Future Wastewater Treatment Systems in
CBRM project. This report will present preliminary design options for the new WWTP, as well as a
detailed discussion of the processes involved and their associated costs.
1.2 Background
The wastewater collection system in the community of New Waterford, as in many communities
throughout CBRM, currently discharges untreated wastewater to the Atlantic Ocean. The evolution of the
existing wastewater collection and disposal systems in CBRM included the creation of regions of a
community which were serviced by a common wastewater collection system tied to a local marine outfall.
Such design approaches have traditionally been the most cost‐effective manner of providing centralized
wastewater collection, and the marine environment has long been the preferred receiving water given the
available dilution. Due to a changing regulatory environment, CBRM is working toward intercepting and
treating the wastewater in these communities prior to discharge.
1.3 Objectives
The objectives of this report will be to:
Establish design parameters for a new WWTP.
Evaluate treatment process alternatives.
Present a preliminary engineering design, with capital and operating cost estimates, for a new
WWTP to meet the design requirements.
HEJV New Waterford WWTP Preliminary Design Brief 2
CHAPTER 2 EXISTING CONDITIONS
2.1 Description of Existing Infrastructure
The New Waterford wastewater collection system includes the former Town of New Waterford, the
community of Scotchtown and a small portion of River Ryan. This area drains to two wastewater
outfalls, both of which discharge at the Barachois. The system consists of approximately 70km of gravity
sewer and 2.6km of force main. There are also a number of lift stations within the system located as
follows:
Nicklewood Drive.
Columbus Street.
Oceanview Boulevard.
Hinchey Avenue.
New Waterford Highway (E‐One system).
E‐One systems are individual home sewage pumping systems that discharge to a common pressure sewer.
In some instances, the flow is first discharged to a septic tank and the effluent from the septic tank is
pumped. In other instances, flow is pumped directly from the home.
2.2 Wastewater Flow Characteristics
Flow meters were installed in the sewer system, upstream of the NW1 and NW2 outfalls, in summer of
2018. A flow meter was previously installed upstream of the NW2 outfall in spring of 2018. The meter
on the NW1 outfall catchment was installed as close to the outfall as possible, but upstream of the area
of tidal influence. This meant that some areas of the NW1 catchment could not be included in the
metering. Results of the flow metering activities are summarized in this section. Flow meter data is
plotted on a series of Figures in Appendix A. The dates of flow data collection at each location are
summarized in Table 2.1.
Table 2.1: Flow Meter Installation Summary
Meter Dates
NW1 August 1 – August 17, 2018
NW2 February 28 – May 11, 2018
August 1 – August 22, 2018
HEJV New Waterford WWTP Preliminary Design Brief 3
2.2.1 Dry Weather Flows
The average dry weather flow (ADWF) results for each of the meter locations is summarized in
Table 2.2. Please refer to the New Waterford Collection System Pre‐Design Brief (Dillon Consulting
Limited, 2019) for more details on the ADWF analysis. The average dry weather flow was defined as the
average flow for flows that met the following criteria:
No rain within the last 24 hours.
No more than 5 mm in the previous 48 hours.
No more than 5 mm per day additional in the subsequent days (e.g. 10 mm in the last 3 days).
Table 2.2: Flow Meter Data Summary – Average Dry Weather Flows
Meter Area (ha) Population ADWF (m3/day) ADWF
(L/cap/d) ADWF (m3/ha/d)
NW1 207.2 2,910 3,404 1,170 16.4
NW2 79.6 1,046 769 735 9.7
Metered Total 286.8 3,956 4,173 1,055 14.6
The dry weather flow in NW1 is very high, at more than 1000 L per person per day (L/cap/d). This flow
was metered during a period of very low rainfall following a month of very low rainfall, during the
summer of 2018. In contrast, the dry weather flow for NW2 during the same summer period was only
297 L/cap/d, which shows low influence from groundwater infiltration. The overall dry weather flow for
NW2 in Table 2.2 is increased due to higher dry weather flows in the spring runoff season, which is
typical for this season, and is further broken down by season in Table 2.3.
Table 2.3: Flow Meter Data Summary – NW2 Sewershed ADWF by Season
Meter ADWF (m3/day) ADWF (L/cap/d)
NW2 (Spring) 1,123 1,074
NW2 (Summer) 311 297
NW2 Metered Total 769 735
In order to determine a projected total ADWF, the flow for the unmetered areas was calculated using
unit flow rates from Table 2.2. Since the entire unmetered area, with a population of 3464, is located in
the NW1 sewershed, unit rates for this area were used for the projection to the serviced total ADWF. As
shown in Table 2.4, below, the total projected ADWF was calculated to be 7,456 m³/d when calculating
the unmetered flow based on population, and is slightly lower based on area. The metered data
represents approximately 53% of the total population, and 56% of the total area.
Table 2.4: NW1 Sewershed ADWF Projection Based on Area and Population
Meter Area (ha) ADWF by area
(m3/day) Population ADWF by population
(m3/day)
NW1 (metered) 207 3,404 2,910 3,404
NW1 (unmetered) 223 3,667 3,464 4,052
NW1 Total 430 7,071 6,374 7,456
HEJV New Waterford WWTP Preliminary Design Brief 4
In order to remove the effect of the excessive dry season flows in NW1, the average overnight flow
minimums were examined for both NW1 and NW2 sewershed data, for a week’s worth of flow in the
driest week for which we have data. The overnight minimum flow in NW2 was 158 L/cap/d, and the
overnight minimum flow for NW1 was 520 L/cap/d. Wastewater production at 3 am is typically very
low, but not zero. If the minimum flows in NW2 are assumed to be reasonable overnight flow, then
NW1 flows should be able to approach this level during dry weather, in the absence of an industrial
process that discharges significant volumes at night; therefore, the difference in overnight flow rates
between the two catchments is likely to be unnecessary extraneous flow. This may result from heavy
groundwater infiltration or from a stream entering the sewer in NW1. Flow equivalent to (520–158=362
L/cap/d) for NW1 catchment was therefore removed from the design flows.
The resulting flows following projection to the full serviced population and adjustment for excessive
extraneous flows as described above are shown in Table 2.5, below.
Table 2.5: Projected and Adjusted Average Dry Weather Flows
Parameter ADWF (L/s, adjusted) ADWF (m3/day, adjusted)
NW1 Flow 59.6 5,150
NW2 Flow 8.9 770
Projected Total Flow 68.5 5,920
2.2.2 Average Day Flows
The average daily flow (ADF) results for each of the meter locations and periods is summarized in Table
2.6. This incorporates all metered data, including rain events.
Table 2.6: Flow Meter Data Summary – Average Daily Flows
Meter Area (ha) Population ADF (m3/day) ADF (L/cap/d) ADF (m3/ha/d)
NW1 Metered Total 207.2 2910 3558 1223 17.2
NW2 (Spring) 79.6 1046 1,822 1742 22.9
NW2 (Summer) 79.6 1046 661 632 8.3
NW2 Metered Total 79.6 1046 1565 1496 19.7
Metered Total 286.8 3,956 5,123 1,295 17.9
In order to project the flow to the entire NW1 sewershed, the unit rates in Table 2.6 were applied for both
area and population, and an assumed seasonal factor of 1.2 x metered ADF was applied to calculate the
total NW1 ADF since the flow data was collected during a period with very little rain, and we would not
expect the actual ADF to be so close to the ADWF. The results are shown in Table 2.7, below. The total
projected ADF was calculated to be 9,352 m3/day when calculating the unmetered flow based on
population. When calculating the unmetered flow based on area, the result was similar. The metered data
represents approximately 53% of the total population and 56% of the total catchment area.
HEJV New Waterford WWTP Preliminary Design Brief 5
Table 2.7: Projected NW1 Average Daily Flows
Parameter Area (ha) ADF by area
(m3/day) Population ADF by pop.
(m3/day)
NW1 (metered) 207 3,558 2,910 3,558
NW1 (unmetered) 223 3,833 3,464 4,235
NW1 Total with Seasonal Factor of 1.2 430 8,869 6,374 9,352
The estimated total average flows currently produced are shown in Table 2.8, below. Due to the limited
data for NW1, the flows for this area were projected using unit rates and then uprated by a seasonal
factor of 1.2, as described above. For NW2, because most of the data were collected in spring, the
average spring flow (likely the highest of the year) was calculated along with the average summer flow
(likely the lowest), and these two averages were equally weighted instead of being weighted by the
respective number of days in each monitoring period.
Table 2.8: Current Total Average Flows
Sewershed Projected ADF (m³/day)
NW1 9,352
NW2 1,255
Total Average Flow 10,607
2.2.3 Peak Day Flow
A selection of measured peak day flows (PDF) from each of the meter locations and periods is displayed
in Table 2.9.
Table 2.9: Flow Meter Data Summary – Peak Day Flow
Meter (Season) 48hr Rainfall
(mm)
Area
(ha) Population PDF
m3/day L/cap/d m3/ha/d
NW1 (Summer) 17.1 207.2 2,910 5,116 1,758 25
NW2 (Summer) 17.1 79.6 1,046 834 797 10
NW2 (Summer) 47.8 79.6 1,046 3,700 3,537 46
NW2 (Spring) 51.0 79.6 1,046 14,388 13,755 181
It is unlikely that any of these data points reflect the true peak flows, due to the limited data collected.
Comparing the two sewersheds in summer, NW2 displays sharper rises in flow from the surrounding
average flow than does NW1, given the same amount of rain. This is expected because it has less I&I
present in the summer months, and therefore a smaller base flow. Spring peak flows in NW2 are more
extreme than in summer, and on a per person basis, are very high. This is anticipated to some extent,
because dry ground has more capacity to absorb flow without runoff; however, the spring flows in NW2
are so high per person that it appears there is excessive I&I entering the system during wet weather,
which should be investigated and addressed.
HEJV New Waterford WWTP Preliminary Design Brief 6
2.2.4 Extraneous Flow Reduction
It is strongly recommended that, at a minimum, additional metering be conducted at the NW1 location
during spring conditions prior to detailed design, in order to identify sources of I&I. Due to the high dry
weather flows and the extremely high wet weather flows observed upstream of NW2 during spring, and
the high dry weather flows observed upstream of NW1 during summer, it is strongly recommended that
efforts be made to locate and reduce sources of inflow and infiltration in both sewersheds prior to
detailed design.
Efforts to identify and prevent excessive extraneous flow are necessary to allow successful and cost‐
effective treatment of the wastewater, and are assumed to take place in order to develop these design
parameters. If these flows are not able to be removed to the degree assumed, then the WWTP may
experience significant occurrences and/or periods of flow bypass because the design capacity of the
plant is less than the actual flows that the collection system conveys.
Nonetheless, a significant amount of inflow and infiltration (I&I) will be collected and treated under the
design parameters developed in this report, and opportunities remain, in both sewersheds, for
additional I&I reduction and potential WWTP size reduction and resulting cost savings.
2.3 Wastewater Quality Characteristics
HEJV collected one untreated wastewater sample upstream of each outfall. The samples for NW1 and
NW2 were collected on April 25, 2018, and April 23, 2018, respectively, and the results are summarized
in Table 2.10. For simplicity, only the parameters of relevance to the preliminary design are included.
Refer to the ERA report for the complete analytical results.
Table 2.10: 2018 Wastewater Characterization Results – General Chemistry
Parameter Outfall
NW1 NW2
CBOD5 (mg/L) 93 140
COD (mg/L) 170 260
Total NH3‐N (mg/L) 2.3 3.1
TSS (mg/L) 110 60
TP (mg/L) 1.4 1.6
TKN (mg/L) 9.9 10
pH 6.59 6.58
Un‐ionized NH3 (mg/L) 0.0025 0.0032
E. coli (MPN/100mL) 1,000,000 >240,000
CBRM collected a number of untreated wastewater samples from 2015 through 2018 at NW1, Dillon
Consulting collected one sample at each of the outfalls in 2014, and UMA Engineering collected a
number of samples in 1992 from both NW1 and NW2. The results of these historical samples are
summarised in Table 2.11.
HEJV New Waterford WWTP Preliminary Design Brief 7
Table 2.11: Historical Wastewater Characterization Results
Outfall Pop.
TSS (mg/L) CBOD (mg/L) Total Ammonia
(mg/L) TKN (mg/L) pH
#
Samples Avg #
Samples Avg #
Samples Avg #
Samples Avg #
Samples Avg
NW1 6,374 106 74 106 105 27 6.41 5.00 39.1 57 6.98
NW2 1,046 26 69 26 104 1 3.30 4.00 45.6 26 7.24
Weighted Average
(by population) ‐ 73 ‐ 105 ‐ 5.97 ‐ 40.0 ‐ 7.01
2.4 Wastewater Loading Analysis
The theoretical per person loading rates listed in the Atlantic Canada Wastewater Guidelines Manual
(ACWGM) (ABL Environmental Consultants Limited, 2006) are 0.08 kg CBOD/person/day and
0.09 kg TSS/person/day. The reference theoretical TKN loading rate of 0.0133 kg TKN/person/day is
stated in Wastewater Engineering: Treatment and Reuse (Metcalf & Eddy, Inc, 2003).
Loads were calculated from three samples with concurrent flow data available (two from NW1 and one
from NW2). The average value for 2018 was also calculated based on the calculated average flow rate
of the NW1 sewershed (including all measured extraneous flows, and assuming that the average flow is
about 1.2 times the average flow calculated from the summer flow data) and the average 2018 NW1
concentration data. These values are shown in Table 2.12, below.
Table 2.12: Calculated and Theoretical Loading Rates
Sampling Date CBOD (kg/cap/d) TSS (kg/cap/d) TKN (kg/cap/d)
April 23, 2018 (NW2) 0.15 0.06 0.011
August 2, 2018 (NW1) 0.23 0.12 –
August 17, 2018 (NW1) 0.13 0.08 –
Average 2018 (NW1) 0.11 0.08 –
Theoretical Loading from Reference 0.08 0.09 0.013
For TSS and TKN, the theoretical loading rates appear to be reasonable for the current data. The higher
TKN concentrations found in the historical data were all from 1992, and the more recent data, though
limited, does not appear to be similarly high. For CBOD, however, the calculated loading rates are all
higher than theoretical. This is also supported in the historical data, where the ratio of CBOD
concentrations to TSS concentrations averages 1.4, which is somewhat atypical. If theoretical loading rates
applied for both constituents, we would expect to see CBOD concentrations that were, on average, slightly
lower than TSS concentrations. It appears that there may be a source of organic material and CBOD in the
community which could be resulting from food processing (for example, Horyl’s Superior Sausage) or
another source of relatively high‐organics wastewater. Additional sampling and concurrent flow
monitoring must be undertaken prior to detailed design to confirm the actual loading rates at that time.
HEJV New Waterford WWTP Preliminary Design Brief 8
For design loading conditions, the theoretical values were used for TSS and TKN, and the average 2018
NW1 value was used for BOD, since the data for NW2 also indicate somewhat elevated CBOD
concentrations compared to TSS. These are shown in Table 2.13, below.
Table 2.13: Design Loading Rates
Parameter Value
Population 7,420
CBOD (kg/cap/d) 0.11
TSS (kg/cap/d) 0.09
TKN (kg/cap/d) 0.013
HEJV New Waterford WWTP Preliminary Design Brief 9
CHAPTER 3 BASIS OF DESIGN
3.1 Service Area Population
The primary method used to estimate future wastewater flows and loads is to project current per capita
flows and loads based on estimates of future population. The population for the New Waterford service
area was obtained based on the 2016 Census data from CBRM’s GIS database using the following
procedure: Each residential unit within the service area boundary from CBRM’s structure database was
multiplied by the average household size for the census dissemination area that it falls within. For New
Waterford, the service area population was estimated to be 7,420 people in 3,735 residential units.
The population of the CBRM has been declining and this trend is expected to continue. The latest
population projection study, completed in 2018 by Turner Drake & Partners Ltd., predicted a
17.8% decrease in population in Cape Breton County between 2016 and 2036. For this reason, no
allocation has been made for any future population growth. For the purpose of this preliminary design
study, WWTP sizing will be based on the current population and measured flow data. While this may
seem overly conservative, due to significant amounts of inflow and infiltration (I&I) observed in sewer
systems in the CBRM, a given population decrease will not necessarily result in a proportional decrease
in wastewater flow. Therefore, basing the design on current conditions is considered the most
reasonable approach.
As the target date for this WWTP is 2040, consideration should be given to re‐evaluating the population
and wastewater flows if a significant amount of time has passed between completion of the pre‐design
study and the project moving to the detailed design stage.
3.2 Design Flows and Loads
As described in Section 2.2, the Average Dry Weather Flow was calculated from the metered data using
a projection to the full serviced population and adjustment for excessive extraneous flow. The resulting
ADWF is 5,920 m³/d (68.5 L/s).
Due to the size, the WWTP will be a mechanical treatment plant which cannot be efficiently designed for
a very wide flow range. Typical design values for peaking factor range from 2 to 3.5 for mechanical
treatment plants. Therefore, a peaking factor of 3.5 was applied for interception based on
recommendations in the Industrial Cape Breton Wastewater Characterization Program – Phase II report
(UMA Engineering Limited, 1994) which recommended a rate of 3.5 times ADWF for this plant. This
interception ratio was also carried forward in the New Waterford Collection System Pre‐Design Brief
HEJV New Waterford WWTP Preliminary Design Brief 10
when considering the design of the pumping stations serving the plant, resulting in a maximum
intercepted flow of 210 L/s for the proposed NW1 Lift Station, and 32 L/s for the proposed NW2 Lift
Station. All flow is pumped to the plant, so these numbers set the peak hour flow (PHF) to the plant as
20,910 m³/d (242 L/s), which is also anticipated to be the peak day flow (PDF).
In order to calculate the average intercepted flow to the plant, and thus the design ADF to the plant,
several adjustments must be applied. The first is applied to both sewersheds, and involves calculating the
average flow to the plant once the maximum flow from each sewershed is capped at the interception rate:
flow data higher than 210 L/s in NW1 and higher than 32 L/s in NW2 are truncated, so that only flow
accepted at the plant is included. Due to the timing of the data collection, this only changes NW2 flows,
and not NW1 flows. Next, a seasonal correction is applied to both sewersheds. The average flow for NW1
is multiplied by a seasonal correction factor of 1.2, to correct for the fact that the data for this sewershed
were collected largely during very dry weather. The data for NW2 were collected mostly in wet weather,
so the average for each season was calculated and weighted equally. Finally, a base‐flow adjustment to
the NW1 sewershed is applied (362 L/cap/d reduction, just as to the ADWF for NW1). All data for NW1
was collected during a dry time in the summer; the flows removed by this adjustment are considered to be
excessive flows, which are not reasonable to collect and treat, and the sources of which must be identified
and removed. The results of these calculations are shown in Table 3.1.
Table 3.1: Estimated Intercepted Average Daily Flow
Sewershed ADF (m3/day)
NW1 7,045
NW2 928
Total Estimated Intercepted ADF 7,973
The resulting design flows, based on the flow meter data and adjustments, which were summarized in
Section 2.2 and in this section, are shown in Table 3.2, below. They are rounded for ease of use.
Table 3.2: WWTP Design Flows
Parameter Value
Average Dry Weather Flow (m³/day) 6,000
Peak Day Flow (m³/day) 21,000
Average Daily Flow (m³/day) 8,000
Based on the metered flows from NW2 in 2018, there would have been 8 periods of overflow at Lift
Station NW2 during the metering period. Spring flows typically represent the worst case condition for
overflows due to increased base flow associated with higher groundwater tables, combined with snow
melt. The metered NW2 data is plotted in Figure 3.1. The average NW2 flow and design NW2
intercepted flows are also plotted on this figure, for comparison. This figure shows flow data from the
NW2 meter only (the NW1 meter was not installed in spring) and may not be representative of the flows
or the overflow frequency from the NW1 sewershed.
HEJV New Waterford WWTP Preliminary Design Brief 11
Figure 3.1: NW2 Flow Data Compared to Intercepted NW2 Flows
Additional metering must be completed upstream of NW1 and NW2 during spring conditions prior to
detailed design, and the resulting data used to locate and reduce sources of I&I. The flow data from
both sewersheds currently indicate high levels of inflow and infiltration, and this must be reduced in
order to successfully collect and treat the wastewater without frequent overflows.
We believe that the design flows selected are a reasonable compromise between capturing the bulk of
the wastewater, and cost‐effectively treating it in a mechanical plant which has a specific flow range
capability. Therefore, the average and peak day design flows chosen for the predesign of the New
Waterford WWTP are 8,000 m3/d and 21,000 m3/d, respectively. Efforts to reduce I&I are required
between now and 2040 in order to achieve these flows. It may be possible to do better than this and
have capital and operating cost savings if this this is done successfully.
3.3 Effluent Requirements
The effluent requirements will include the federal WSER limits, along with provincial effluent
requirements determined by NSE and presented in the NSE Approval to Operate for the WWTP. An ERA
was completed in 2018 which determined effluent discharge objectives for parameters not included in
the WSER (See Appendix B).
HEJV New Waterford WWTP Preliminary Design Brief 12
The receiving water for the New Waterford WWTP will be the Atlantic Ocean, adjacent to the Barachois.
The ERA generally followed Technical Supplement 3 of the Canada‐wide Strategy for the Management of
Municipal Wastewater Effluent – Standard Method and Contracting Provisions for the Environmental Risk
Assessment. Dilution modelling was conducted to determine the maximum 1 day average effluent
concentration with a mixing zone boundary of 100m for all parameters of concern with the exception of E.
coli for primary contact recreation. The E. coli concentration was analyzed at the edge of the 100m mixing
zone for secondary contact recreation, and at Brown’s Road Extension Beach for primary contact recreation.
Refer to Table 5.1 in the ERA attached in Appendix B for Effluent Discharge Objectives (EDOs) developed
during the ERA and for further information on the development of these values.
The effluent requirements resulting from the ERA are summarized in Table 3.1 along with the sources of
the criteria. As EDOs are calculated values, they are not round whole numbers that are typical of
effluent requirements; therefore, we have included both the EDOs and values that are more suited as
effluent requirements in the table.
Table 3.3: Design Effluent Requirements
Parameter EDO Required By Effluent Limit
CBOD5 (mg/L) 25 WSER 25
TSS (mg/L) 25 WSER 25
Un‐ionized Ammonia (as NH3‐N) (mg/L) 1.25 WSER 1.25
Total Residual Chlorine (TRC) (mg/L) 0.02 WSER 0.02
E. coli (cfu/ 100mL) 57,186 NSE 200
TN (mg/L) 49.3 ERA 50
Phosphorus (mg/L) 4.0 ERA 4
3.4 Design Loads
The wastewater concentrations vary significantly as was shown in Sections 2.3 and 2.4. For design purposes,
we are going to use the calculated per person loads shown in Table 2.13. The peak loading rate per person
was approximately double the average rate. The resulting loads are shown in Table 3.4, below.
Table 3.4: Design Loading Summary
Parameter Average Day Peak Day
Design Population 7,420
Flow (m3/day) 8,000 21,000
CBOD Load (kg/day) 890 1,780
TSS Load (kg/day) 670 1,340
TKN Load (kg/day) 100 200
HEJV New Waterford WWTP Preliminary Design Brief 13
CHAPTER 4 TREATMENT PROCESS ALTERNATIVES
Achieving the effluent criteria described in the preceding chapter requires the selection of an overall
wastewater treatment process that includes a secondary treatment process. Secondary treatment
processes are predominantly aerobic biological processes designed to convert the finely dispersed and
dissolved organic matter in the raw wastewater into flocculent settleable biological cell tissue (biomass)
which can be removed by sedimentation. These biological processes are the most efficient in removing
organic substances that are either dissolved or in the colloidal size range (too small to settle out),
whereas primary treatment processes are the most efficient in removing larger particles of suspended
solids which can be removed by sedimentation, fine screening, or filtration.
4.1 Preliminary Treatment
A variety of secondary treatment process options will be evaluated. However, each option will require
preliminary treatment of the wastewater. The purpose of preliminary treatment processes is to remove
objectionable materials and inorganic particles from the wastewater prior to treatment. These
processes may include screening or coarse solids reduction, and grit removal.
4.1.1 Screening
Screens used in preliminary treatment applications are classified based on the size of openings as either
coarse (6 to 150 mm openings) or fine (less than 6 mm openings).
Coarse screens are used to remove large objects that could damage or clog downstream equipment, so
they are typically the first unit operation in a wastewater treatment plant. Coarse screens may be either
hand cleaned or mechanically cleaned. There are a number of mechanical cleaning system options
available, including continuous chain driven rakes, reciprocating rake, and continuous belt.
Fine screens provide increased solids capture compared to coarse screens, and are typically required in
front of secondary processes. There are several options available for fine screening, which are described
below.
Rotating perforated plate screens consist of a continuous screen made of panels with punched holes
that allow water to pass through and debris to be captured. The debris collected on the screen is
removed as the screen is raised out of the water as part of its normal rotation. Any debris remaining on
the screen will enter the water downstream of the screen as the screen passes through the water.
HEJV New Waterford WWTP Preliminary Design Brief 14
The step screen operation is considerably different from the perforated plate screen. It is a single piece
screen that does not rotate. The screen is configured in steps and the solids collected on the steps of the
screen are lifted to the next step by tines. The screen has continuous opening to allow for the tines to
lift the screenings from one step to the next and relies on the formation of a filtering mat to assist in the
screening process. This operation results in the screenings being handled on the screen several times
before it is removed which can cause the screenings to breakdown and pass through the screen and re‐
enter the water downstream of the screen.
Screw screens include a punched plate through which the wastewater flows, and a rotating shaftless
screw that moves material captured by the plate up to a compaction zone and out the top to a bin.
These are often used for smaller applications.
In general, for a given aperture size, perforated plate screens have much higher solids capture ratios
than step screens, and screw screen capture ratios are in between these two. For perforated plate and
step screens, the screenings should then be directed to a washer compactor to reduce the volume of
screenings and return organics to the process so they can be treated, while a screw screen has an
integrated compaction unit, with moderate washing capabilities. A separate washer compactor
produces cleaner, lower odour screenings for disposal.
4.1.2 Grit Removal
Grit chambers are used to remove non‐biodegradable materials such as sand, gravel, cinders, or other
heavy solid material with specific gravities greater than those of organic solids in the wastewater. The
purpose of grit removal is to protect mechanical equipment from abrasion and wear, and to reduce the
formation of heavy deposits in pipelines, channels, and conduits.
Typical grit chamber configurations include horizontal flow‐through, aerated, and vortex. New
applications generally use aerated or vortex‐style grit chambers.
In aerated grit chambers, coarse bubble diffusers are installed along one side of each rectangular tank to
create a spiral flow pattern that is perpendicular to the flow through the chamber. This spiral pattern
causes the grit to settle in the tank and helps keep organic particles in suspension, so they can pass
through the tank and be treated in downstream processes. The performance of an aerated grit chamber
can be controlled by adjusting the quantity of air that is supplied. If the spiral velocities are too low then
organics may settle in the chamber, causing excessive quantities of organics in the dried grit. If the spiral
velocities are too high, then grit may not settle in the chamber. The grit that settles in an aerated grit
chamber settles in a trough that spans the length of the chamber.
There are a number of options available for removing grit from the trough, including:
Grab buckets mounted to monorails.
Chain and bucket systems.
Spiral conveyors and grit pumps.
HEJV New Waterford WWTP Preliminary Design Brief 15
Vortex‐style grit chambers are common in new applications. These systems function by inducing a
helical flow pattern in the tank, and the resulting centrifugal forces cause grit to settle in a hopper. Grit
is then removed from the hopper using a grit pump.
Once grit is removed from the main treatment process, the slurry is then pumped or conveyed to a
classifier for separation and washing. Classifiers may be equipped with a hydrocyclone at the inlet to
reduce slurry volumes through centrifugal separation prior to discharging to the classifier tank. Grit that
settles in the classifier is removed by an auger or rake and discharged to a disposal bin until there are
sufficient quantities for disposal to landfill.
4.2 Secondary Treatment
There are many types of secondary treatment processes available, most of which can be classified as
either suspended growth or attached growth systems. Suspended growth systems use aeration and
mixing to keep microorganisms in suspension and achieve a relatively high concentration of these
microorganisms (biomass) through the recycle of biological solids. Attached growth systems provide
surfaces (media) on which the microbial layer can grow, and expose this surface to wastewater for
adsorption of organic material and to the atmosphere and/or diffused aeration for oxygen. A listing of
specific secondary treatment processes and the category to which they belong is presented in Table 4.1.
Table 4.1: Secondary Treatment Processes
Process Category Specific Process
Suspended Growth Conventional Activated Sludge (CAS)
Extended Aeration
Pure Oxygen Activated Sludge
Sequencing Batch Reactor (SBR)
Oxidation Ditch
Membrane Bioreactor (MBR)
Attached Growth Rotating Biological Contactor (RBC)
Trickling Filter
Biological Activated Filter (BAF)
Moving Bed Bio‐Reactor (MBBR)
Land‐Based Constructed Wetlands
Aerated Lagoon
Facultative Lagoon
HEJV has worked on projects using the majority of the technologies in Table 4.1 so we are able to use
our considerable practical experience to narrow down the list of available technologies to those best
satisfying the project constraints.
4.2.1 Site‐specific Suitability
The main constraints at this site that will influence which of the available options are best suited for the
New Waterford WWTP are: effluent requirements, site conditions, cost effectiveness, and ease of
operation. Each of these is discussed below.
HEJV New Waterford WWTP Preliminary Design Brief 16
4.2.1.1 EFFLUENT REQUIREMENTS
The effluent requirements summarized in Section 3.3 can be met by all of the listed technologies in
Table 4.1 with the exception of the facultative lagoon, which has been eliminated from further
consideration.
4.2.1.2 SITE CONDITIONS
A location to the west of the Barrachois has been identified as the location of the New Waterford
WWTP, since both outfalls currently discharge in this area. The site selection is described in the New
Waterford Collection System Predesign Report. In the general area identified as the site for the WWTP,
there is a large parcel to the east of Mahon Street (PID 15483100) that is owned by Public Works and
Government Services Canada. West of Mahon Street, there is another large parcel (PID 15492747)
owned by Margaret McLellan. Construction of the WWTP will require acquisition of one or more of
these properties. However, with any of these properties, the Atlantic Canada Wastewater Guidelines
Manual (ACWGM) recommended separation distances will not be met. The Atlantic Canada
Wastewater Guidelines Manual (ACWGM) recommends that mechanical plants be located a minimum of
150m from residences, 30m from commercial/industrial developments, and 30m from property lines.
However, a lesser separation distance may be adopted provided odour control is provided at the plant.
HEJV have eliminated wetlands and aerated lagoons from further consideration as they require
additional area that is not available at this site.
4.2.1.3 COST EFFECTIVENESS
There are a number of processes in Table 4.1 that can be eliminated based on their cost effectiveness
compared to other processes in the table. For example, pure‐oxygen activated sludge is more costly than
conventional activated sludge due to its requirement for specific equipment to reduce the footprint of the
activated sludge process. For larger flows, extended air and oxidation ditches are less cost effective than
SBR, due to the larger tanks required. The footprint of these options would probably also exclude them
from use on the sites available. Two of the attached growth options require large areas for media (trickling
filter and RBC) and do not tend to perform well in our climate, while the BAF is not typically cost
competitive for low‐strength wastewater. Membrane bioreactors (MBR) are also not typically a cost
effective treatment process when the effluent discharge criteria do not necessitate their use.
4.2.1.4 EASE OF OPERATION
The remaining technologies (Conventional Activated Sludge, MBBR, and SBR) typically require similar
levels of operational expertise, which we would classify as moderate. However, there is an operational
benefit to using an SBR process as the CBRM WWTP operations staff have experience with this type of
process already.
4.2.2 Description of Candidate Processes for Secondary Treatment
Based on the preceding analysis, the following processes should be given further consideration:
Conventional Activated Sludge (CAS).
Sequencing Batch Reactor (SBR).
Moving Bed Bioreactor (MBBR).
HEJV New Waterford WWTP Preliminary Design Brief 17
Each of these processes is described below. Each of the secondary treatment processes will have similar
solids stream trains, so the sludge handling processes will not be evaluated at this stage. Similarly, the
costs associated with site access, outfall, electrical service etc. will not be evaluated as part of the
secondary treatment process comparison.
4.2.2.1 CONVENTIONAL ACTIVATED SLUDGE
The conventional activated sludge (CAS) process is a continuous‐flow, aerobic suspended‐growth
biological treatment process that has become the most common method of treatment for BOD and TSS
removal. In the activated sludge process, organic waste material is decomposed by microorganisms such
as bacteria, fungi, protozoa and rotifers, which use the waste, or “food”, as energy in the synthesis of
new cells. Aeration is required for the cellular respiration. Many variations of the process currently exist.
The conventional activated sludge process follows the primary treatment step. The effluent from the
primary clarifier serves as the influent for the AS process. The biological treatment is carried out in the
AS reactor, in which aeration is provided to keep the biomass and waste material in suspension, as well
as ensure completely mixed conditions in the reactor. This is required to promote contact between the
microorganisms, waste material and oxygen. The mixture is commonly referred to as the “mixed liquor”.
The hydraulic retention time – defined as the average amount of time a water molecule spends in a tank
– in conventional AS reactors is typically 6 to 10 hours under average flow conditions. Somewhat larger
reactors and additional aeration capacity are required if nitrification is to be achieved in addition to
carbonaceous BOD reduction.
The flocculent biomass from the AS reactor discharges to a secondary clarifier (typically circular) where
biological floc material is settled out in a similar manner to that of a primary clarifier. In order to
maintain a sufficient concentration of activated sludge in the aeration tank, a portion of the sludge that
is collected in the secondary clarifier is recycled to the aeration tank. This recycled portion is referred to
as return activated‐sludge (RAS). Excess sludge, the waste activated‐sludge (WAS), is removed from the
system on a regular basis in order to control the solids retention time (SRT), which is defined as the
average amount of time the sludge has remained in the system. WAS is typically discharged to a
thickening process. Typical SRTs for activated sludge processes range from 4 to 15 days.
A typical conventional activated sludge secondary process schematic is provided in Figure 4.1. The
influent to the process is effluent from a primary clarifier, which is not shown in the figure. The primary
clarifier is assumed to be a standard rectangular clarifier with mechanical scrapers for sludge removal.
HEJV New Waterford WWTP Preliminary Design Brief 18
Figure 4.1: Typical Conventional Activated Sludge Secondary Process Schematic
A conceptual level cost estimate has been developed for this option based on the projected design flow and
loads, as well as on the design parameters listed in Table 4.2.
Table 4.2: Conventional Activated Sludge Process Design Criteria
Parameter Proposed Typical Design Standard
No. of Primary Clarifiers 2 –
Primary Clarifier Length (m) x Width (m) 22.0 x 5.5 –
Primary Clarifier Depth 3.5 3 – 4.9
Primary Clarifier Average/ Peak SOR (m3/m2/d) 33 / 87 40 / 100
Primary Clarifier Detention Time (hr) 2.5 1.5 – 2.5
Aeration Tank Reactor Volume (m3) 2,500 –
Aeration Tank Average HRT (hr) 7.5 6 – 10
Aeration Tank Peak Day HRT (hr) 3 3 – 4
Aeration Tank MLSS (mg/L) 1,600 1,500 – 4,000
Aeration Tank Average F/M Ratio 0.2 0.2 – 0.6
No. of Secondary Clarifiers 2 –
Secondary Clarifier Diameter (m) 15.5 –
Secondary Clarifier Depth (m) 3.5 3.5 – 6
Secondary Clarifier Average SLR (kg/m2hr) 2.6 4 – 6
Secondary Clarifier Peak SLR (kg/m2hr) 7.2 8
Secondary Clarifier Average SOR (m3/m2/d) 21 16 – 28
Secondary Clarifier Peak SOR (m3/m2/d) 56 40 – 64
Aeration
Tank
Secondary
Clarifier
RA
S
Secondary
Effluent
Blowers
WA
S
to
Dig
e
s
t
e
r
HEJV New Waterford WWTP Preliminary Design Brief 19
4.2.2.2 SEQUENCING BATCH REACTOR
The Sequencing Batch Reactor (SBR) process is also an aerobic suspended‐growth biological treatment
process and is essentially a modified version of the completely mixed activated sludge process, with the
main difference being the mode of operation. The SBR process is a batch process whereby secondary
treatment, including nitrification, is achieved in one reactor. The SBR process is a “fill and draw” type
reactor where aeration and clarification occur in the same reactor. Settling is initiated after the aeration
cycle and supernatant is withdrawn through a decanter mechanism.
An example of the cycles used in the SBR process is summarized below. However, there are variations
between different manufacturers.
1. Fill – Preliminary treatment effluent enters the anoxic pre‐react zone in the SBR tank. The anoxic
conditions favor the procreation of microorganisms with good settling characteristics. The
wastewater then flows into the react zone of the SBR.
2. React – The microorganisms contact the substrate and a large amount of oxygen is provided to
facilitate the substrate consumption. During this period aeration continues until complete
biodegradation of BOD and nitrogen is achieved. During this stage some microorganisms will die
because of the lack of food and will help reduce the volume of the settling sludge. The length of the
aeration period determines the degree of BOD consumption.
3. Settle – Aeration is discontinued at this stage and solids separation takes place leaving clear, treated
effluent above the sludge blanket. During this clarifying period no liquids typically leave the tank to
avoid turbulence in the supernatant.
4. Decant – This period is characterized by the withdrawal of treated effluent from approximately two
feet below the surface of the mixed liquor by the floating solids excluding decanter. This removal
must be done without disturbing the settled sludge.
5. Idle – An idle period can be provided between cycles. Sludge wasting can also occur during this time.
The process is generally implemented using a minimum of two (2) reactors in parallel. It can be
conducted as a batch process where one reactor is filling while the other is settling. Continuous‐feed
SBRs are also available which receive influent during all phases of the treatment cycle and decant
intermittently. No RAS is required as the mixed liquor remains in the reactor at all times, with WAS
being withdrawn as necessary. The entire process is controlled using a programmable logic controller
(PLC). A typical process schematic for the SBR system is provided in Figure 4.2.
HEJV New Waterford WWTP Preliminary Design Brief 20
Figure 4.2 Typical Sequencing Batch Reactor Secondary Process Schematic
SBRs are operated at long solids and hydraulic retention times, resulting in large reactor volumes;
however, the total number of tanks required is reduced, which can result in more compact site layouts.
Furthermore, since flow equalization is inherently provided in SBR systems, the process is much more
resistant to shock loadings, making it an attractive alternative for small to medium sized facilities. Due
to the degree of control required and the large volume of tankage required in each reactor, the capital
costs are often higher than more conventional activated sludge processes for larger plants. The
discharge for smaller systems is typically intermittent in nature, which can result in larger, more
expensive UV disinfection systems.
A conceptual level cost estimate has been developed for this option based on the projected design flow,
loads, and design parameters listed in Table 4.3.
Table 4.3: Sequencing Batch Reactor Process Design Criteria
Parameter Proposed Typical Design Standard
No. of Reactors 2 3 – 4
Basin Length (m) 48.2 –
Basin Width (m) 15.1 –
Side Water Depth (m) 5.5 –
Total Reactor Volume (m³) 8,006 –
Design HRT (hr) 24 15 – 40
Cycles per Reactor per Day (average / peak) 6 / 8 4 – 6
React Time (min) (average/ peak) 120 / 90 60 – 120
Settling Time (min) (average/ peak) 60 / 30 30 – 60
Volumetric BOD5 Loading (kg BOD /m³d) 0.1 0.1 – 0.3
MLSS (mg/L) 2,500 2000 – 5000
F/M Ratio 0.05 0.04 – 0.1
WAS to Digester
Preliminary
Effluent
Blower
Aeration Tank
2. React
Secondary
Effluent
Blower
Aeration Tank
1. Fill
Secondary
Effluent
Blower
Aeration Tank3. Settle
Secondary
Effluent
Blower
Aeration Tank4. Draw
Secondary
Effluent
WAS
Preliminary
Effluent
Preliminary
Effluent
Preliminary
Effluent
HEJV New Waterford WWTP Preliminary Design Brief 21
4.2.2.3 MOVING BED BIO‐REACTOR
The patented Moving Bed Bio‐Reactor (MBBR) process was developed by the Norwegian company
Kaldnes Miløteknologi (KMT). MBBRs are a system based on a biofilm reactor with no need for
backwashing or return sludge flow. The MBBR contains what is termed as a “carrier” which is a
manufactured (typically plastic) media with a high specific surface area for biofilm to grow. The specific
gravity of the carrier is slightly less than that of water so that aeration will keep the contents in
suspension and completely mixed. The movement is normally caused by coarse‐bubble aeration.
Abrasion of the media carriers sloughs off and maintains optimal biofilm thickness.
Effluent from preliminary treatment serves as the influent to the MBBR unit. MBBR effluent containing
suspended solids then overflows to a secondary clarifier or DAF clarifier for solids removal; however, the
carrier material remains in the reactor. A typical MBBR process schematic is provided in Figure 4.3.
Figure 4.3: Typical Moving Bed Bio‐Reactor Process Schematic
A conceptual level cost estimated has been developed for this option based on the projected design flow,
loads, and design parameters listed in Table 4.4.
HEJV New Waterford WWTP Preliminary Design Brief 22
Table 4.4: Moving Bed Bio‐Reactor Process Design Criteria
Parameter Proposed Typical Design Standard
No. of Trains 1 –
No. of Stages 1 –
Total Reactor Volume (m³) 800 –
Average / Peak HRT (hr) 2.4 /0.9 1 – 3
Side Water Depth (m) 5.5 5 – 7.5
Bioreactor BOD5 Loading (g/m2d)(1) 5.1 3.5 – 7.0
Bioreactor Media Specific Surface Area (m²/m³) 800 500 – 1200
Bioreactor Media Fill Ratio (%) 55 30 – 60
Secondary DAF Clarifier Average / Peak SOR (m/d)(2) 213 / 561 60 – 120
(1) Assumes 55% fill rate
(2) Includes baffles and polymer dosing which increase the feasible SOR above typical design values
4.3 Disinfection
Disinfection at WWTPs is typically provided using either chlorination or ultraviolet (UV) disinfection.
Due to the TRC limit in the WSER, use of chlorine disinfection requires a dechlorination system, which
introduces additional equipment and costs. In addition, a UV disinfection system has safety advantages,
and minimizes chemical handling.
UV Disinfection is a physical disinfection process that targets microorganisms such as viruses, bacteria,
and protozoa by destroying their ability to reproduce. Pathogen inactivation is directly linked to UV
dose, which is the product of the average UV intensity and the duration of exposure, or retention time.
Any factor affecting light intensity or retention time will also affect disinfection effectiveness. Some of
the key parameters that affect UV intensity include water quality issues such as:
UV transmittance (UVT).
Suspended solids.
Presence of dissolved organics, dyes, etc.
Hardness.
Particle size distribution.
Other factors affecting UV performance include sleeve cleanliness, age of lamps, upstream treatment
processes, flow rate and reactor design.
4.3.1 CAS/MBBR Effluent Disinfection
Flows from the CAS or MBBR system will flow continuously by gravity to the UV disinfection unit.
Disinfection will take place in a single concrete channel located in the new WWTP building. The UV
system will consist of two banks of UV lamps. The lamps are oriented horizontally and parallel to the
direction of flow and contain twenty‐four lamps per bank for a total of forty‐eight (48) lamps, each with
a rating of 250 W. This is a small to medium‐size system of its type. The disinfected effluent would flow
by gravity to the outfall. The design parameters for the UV disinfection system are summarized in
Table 4.5 below.
HEJV New Waterford WWTP Preliminary Design Brief 23
Table 4.5: CAS/MBBR UV Disinfection Design Parameters
Parameter Design Value
Number of Design Channels 1
Number of Banks 2
Number of Lamps per Bank 24
Total Number of Lamps 48
Peak Flow Capacity (m3/d) 21,000
Effluent TSS (mg/L) <25
Minimum Transmittance (%T) 60
Effluent Fecal Coliforms (MPN/100 mL) 200
4.3.2 SBR Effluent Disinfection
Flows from the SBR system will flow intermittently by gravity to the ultraviolet (UV) disinfection unit
during the decant cycle. This results in a larger UV system being required than for the CAS process as it
is sized for the peak decant rate from the SBR. This larger flow rate makes an inclined array UV system
feasible, because it the flow rate is large enough to warrant the smallest model of this type of system.
Disinfection will take place in a single concrete channel located in the new WWTP building. The UV
system will consist of two banks of UV lamps. The lamps are oriented in a staggered inclined array and
contain twelve lamps per bank for a total of twenty‐four (24) lamps, each with a rating of 1000 W. Each
of the lamps are longer and have a higher output than the lamps in the CAS/MBBR system, and so fewer
lamps are needed to produce the same dose. The disinfected effluent would flow by gravity to the
outfall. The design parameters for the UV disinfection system are summarized in Table 4.6 below.
Table 4.6: SBR UV Disinfection Design Parameters
Parameter Design Value
Number of Design Channels 1
Number of Banks 2
Number of Lamps per Bank 12
Total Number of Lamps 24
Peak Flow Capacity (m3/d) 38,700
Effluent TSS (mg/L) <25
Minimum Transmittance (%T) 60
Effluent Fecal Coliforms (MPN/100 mL) 200
4.4 Sludge Management
Each of the secondary treatment options evaluated will produce sludge which must be removed from
the treatment process on a regular basis and disposed of at an approved facility. Regardless of which
secondary treatment option is selected, sludge management at this facility will likely involve an aerated
sludge holding tank followed by dewatering. After the recommended secondary treatment process has
been selected, a preliminary design of the solids management train will be provided in Chapter 5.
HEJV New Waterford WWTP Preliminary Design Brief 24
4.5 Secondary Treatment Option Evaluation
Capital and operating costs have been developed for each of the secondary treatment options
presented in this section for the purposes of evaluating the technology options. At this stage, only the
liquid treatment stream has been evaluated. As each option will involve a similar solids treatment train,
it has not been included as part of the comparison. Similarly, items such as site access, outfall, electrical
service etc. that are common to each option have not been included at this stage in the evaluation. A
discussion has also been provided on qualitative factors associated with each of the secondary
treatment options.
4.5.1 Capital Cost Estimate
Capital cost estimates are provided in Table 4.7. These are comparative cost estimates for secondary
process alternatives only and exclude sludge management, outfall upgrades, main lift station, and site
works that would be common to all options. Of the three options evaluated, the CAS process has the
lowest capital cost, with SBR a close second (approximately 3% higher). This difference is within the
accuracy of a Class D cost estimate, so no conclusions can be drawn from capital cost alone.
Table 4.7: Secondary Process Capital Cost Comparison
Cost CAS SBR MBBR
Estimated Capital Cost $ 17,421,000 $ 17,896,000 $ 20,255,000
4.5.2 Operating Cost Estimate
The operating cost comparison is provided in Table 4.8. Of the three options, the SBR process has the
lowest operating cost.
Table 4.8: Secondary Process Annual Operating Cost Comparison
Operation Annual Operating Cost (Secondary Process Only)
CAS SBR MBBR
Power(1) $50,000 $50,000 $60,000
Chemicals(2) $ ‐ $ ‐ $14,000
Maintenance Allowance(3) $23,000 $21,000 $37,000
Total $73,000 $71,000 $111,000
Notes:
(1) Power estimated based on secondary treatment equipment only.
(2) Allowance for polymer dosing for the MBBR DAFs.
(3) Maintenance allowance of 1% of equipment cost.
4.5.3 Life Cycle Cost Estimate
Discounted present value calculations were carried out to estimate the Net Present Value of the
treatment plant options. This is the standard method for calculating the relative costs of different
options. Net Present Value (NPV) is calculated using Equation 4.1, where “Cost in period n” is the net
cost in a given year, “n” is the year from 1 to 30, and “rate” is the real discount rate. This cost is
calculated for each year in question and the yearly costs are summed.
HEJV New Waterford WWTP Preliminary Design Brief 25
Equation 4.1 Net Present Value
NPV=∑࢙࢚ ܑܖ ܘ܍ܚܑܗ܌ ܖ
ሺା࢘ࢇ࢚ࢋሻ
The effect of this calculation is that costs which occur soon are weighted more heavily than costs which
occur farther down the road, based on the idea that a dollar today is worth more than a (more
uncertain) dollar next year. The calculations in the report were carried out without applying an assumed
inflation rate. This is called a real NPV. If inflation is used (called nominal NPV), it is applied to both the
costs (which are higher by inflation) and the discount rate (nominal discount rate equals real discount
rate plus inflation, therefore higher) so that the higher costs are discounted faster, and the two effects
cancel each other out, giving the same result whether the real or nominal NPV is calculated. The real
discount rate used in these calculations is 8%, and the time period over which it is calculated is 30 years,
starting in 2019. The net present value is carried out on the capital costs before taxes. These
calculations do not account for the revenue from users.
The life‐cycle comparison is presented in Table 4.9, based on total capital costs, and then based on the
Investing in Canada Plan in Table 4.10. Of the options, the SBR and CAS processes have the lowest
operating cost while the CAS process has a slightly lower life cycle cost. If the life cycle cost was adjusted
to account for CBRM paying 27% of the capital cost the CAS process would still have the lowest life cycle
cost, but they are very similar, and within the accuracy of the estimates.
Table 4.9: Secondary Process Life Cycle Cost Comparison
Cost CAS SBR MBBR
Estimated Capital Cost $ 17,421,000 $ 17,896,000 $ 20,255,000
Estimated Annual Operating Cost, $/yr $ 73,000 $ 71,000 $ 111,000
NPV Equipment Replacement (after 20
years, 8% real discount rate) $ 1,206,000 $ 1,156,000 $ 1,495,000
NPV Operating Cost (30 years, 8%
discount rate) $ 822,000 $ 799,000 $ 1,250,000
Life Cycle Cost $ 19,449,000 $ 19,851,000 $ 23,000,000
Table 4.10: Secondary Process Life Cycle Cost Comparison – 73% Capital Funding
Cost CAS SBR MBBR
Estimated Capital Cost $ 4,704,000 $ 4,832,000 $ 5,469,000
Estimated Annual Operating Cost, $/yr $ 73,000 $ 71,000 $ 111,000
NPV Equipment Replacement (after 20
years, 8% real discount rate) $ 1,206,000 $ 1,156,000 $ 1,495,000
NPV Operating Cost (30 years, 8%
discount rate) $ 822,000 $ 799,000 $ 1,250,000
Life Cycle Cost $ 6,732,000 $ 6,787,000 $ 8,214,000
HEJV New Waterford WWTP Preliminary Design Brief 26
4.5.4 Qualitative Evaluation Factors
In addition to life‐cycle cost, there are a number of other factors to consider when evaluating the
technology options that are less easily quantified. These factors are summarized in Table 4.11, and
additional discussion is provided below the table. Qualitative factors have been rated 1 to 3 for each
technology with 1 being the best and 3 being the worst.
Table 4.11: Secondary Process Qualitative Evaluation Factors
Factor CAS SBR MBBR
Local Experience with Process 2 1 3
Operational Simplicity 2 1 3
Sludge Production 3 2 1
Site Aesthetics 3 2 1
In terms of local experience with the treatment process, CBRM have experience with the SBR process at
the Dominion WWTP. CBRM also have experience with the primary clarification step in the CAS process
at Battery Point.
When considering operational simplicity, all processes are fairly straightforward although each has their
own benefits. The SBR process is more automated while the CAS process allows for more operator
control. The MBBR process is the most complicated because it requires polymer dosing for optimal
performance, while the other two do not.
Each of the secondary treatment processes evaluated will produce sludge that will have to be removed
from the process. The longer HRT provided in the SBR process will result in a slightly lower sludge
production than the CAS process, while the MBBR produces thicker sludge and therefore a smaller
volume to handle before dewatering.
When considering site aesthetics, the MBBR is the most compact, and the SBR is likely to be more
compact than the CAS process. The MBBR process is largely indoors, and the SBR process is conducted in
one tank (although in multiple cells) whereas the CAS process uses different tanks that are connected
via yard piping. The headworks and sludge handling associated with each process has the potential for
odours, but these operations will be enclosed in a building for all technology options. The primary
clarifiers associated with the CAS process would be located outdoors and may have more potential for
odour generation than the SBR or MBBR tanks.
4.5.5 Recommended Secondary Treatment Process
Both the life‐cycle cost evaluation which results in the CAS and SBR processes being very comparable,
and consideration of other qualitative evaluation factors result in the SBR process being the
recommended secondary treatment process for this facility. The SBR process gives the best balance
between cost, operator familiarity, and suitability for a site with neighbours in close proximity.
HEJV New Waterford WWTP Preliminary Design Brief 27
CHAPTER 5 PRELIMINARY DESIGN
5.1 Process Description
Preliminary layouts for the proposed treatment system and locations of individual unit processes are
shown in the “Preliminary Design” drawings, found in Appendix C. The processes depicted in these
drawings are consistent with those recommended in the previous chapter of this report. The drawings
contained in the appendix are presented in Table 5.1, below.
Table 5.1: Preliminary Design Drawings
Drawing Number Description
C01 Location Plan
C02 Process and Admin Building Layout
C03 Site Works Plan
P01 Process Flow Diagram
5.2 Unit Process Descriptions
Drawing C01 in Appendix C includes a site plan showing the location of the proposed new structures.
Further description of the proposed treatment units follows.
5.2.1 Preliminary Treatment
All wastewater will be pumped to the headworks from two lift stations, LS#1 and LS#2. LS1 will pump
wastewater from the NW1 sewershed, with an overflow to the existing NW1 outfall. LS1 will pump
wastewater from the NW2 sewershed, with an overflow to the enlarged and extended NW2 outfall.
Screening
In the WWTP headworks, influent will flow through a perforated plate fine screen with 6mm
perforations. It is expected that screenings will be conveyed to a Screw Washer Compactor to be
washed and dewatered. Dewatered screenings will be discharged into a bin. Wash water will flow by
gravity to the influent channel. The fine screening system will be installed directly into concrete channel,
one per screen, each with a width of approximately 1 m and a depth of approximately 1.5 m. The design
parameters for fine screening are summarized in the Table 5.2.
HEJV New Waterford WWTP Preliminary Design Brief 28
Table 5.2: Fine Screening Design Summary
Parameter Design Value
No. of Screening Units 2
Peak Flow (m3/d) 21,000
Channel Width (mm) 1,000
Channel Depth (mm) 1,500
Screen media 6mm perforated plate
Capture Ratio 75%
No. of Washer Compactor Units 1
Dewatered Screenings (m3/d) 0.2
Solids Content of Screenings (%) 60
Grit Removal
After screening, influent will pass through a vortex grit chamber (either concrete or stainless steel,
assumed to be in a concrete chamber). The purpose of the grit chamber is to capture solids such as
sand particles with diameters larger than 0.2 mm. The grit chamber will be a circular horizontal flow
through chamber with a diameter of approximately 3 m and a depth of approximately 2.5 m. The grit
well has a depth of 1.8 m giving a total depth of approximately 4.3 m. Grit will be pumped from the grit
chamber for grit dewatering. Excess water from dewatering will flow back to the grit chamber inlet
channel by gravity. Dewatered grit will be discharged into a bin. After grit removal, influent will flow to
the SBR tanks by gravity. The design parameters for grit removal are summarized in the Table 5.3.
Table 5.3: Grit Removal Design Summary
Parameter Design Value
No. of Units 2
Peak Flow (m3/d) 21,000
Diameter (m) 3.0
Depth (m) 4.3
No. of Grit Classifier Units 1
Classified Grit Production (m3/d) 0.4
Classified Grit Solids (%) 80
5.2.2 Secondary Treatment
The secondary treatment process will consist of two continuous‐flow SBR tanks. Pre‐treated wastewater
will flow from the vortex grit chamber to the SBR tanks. Influent weirs distribute the flow evenly
between the two tanks. Influent enters an anoxic pre‐react zone before flowing into the react zone
where aeration takes place. Air is supplied to the SBR tanks by blowers via fine bubble diffusers on the
bottom of the tanks. After the blowers are turned off, settling occurs. After the settling period is
complete, decant begins. Decanted effluent flows by gravity to a UV disinfection unit. An air flow meter
and a dissolved oxygen (DO) probe will be provided for each SBR tank. A pressure transducer and a level
float will also be provided for each tank. The design parameters for secondary treatment are
summarized in the Table 5.4.
HEJV New Waterford WWTP Preliminary Design Brief 29
Table 5.4: Secondary Treatment Design Summary
Parameter Design Value
Average Flow (m3/d) 8,000
Peak Flow (m3/d) 21,000
No. of Tanks 2
Tank Dimensions (m) 15.1 W x 48.2 L x 5.5 (plus 1m freeboard)
Total Surface Area (m2) 1,456
Total Volume (m3) 8,006
Ave / Peak HRT (hr) 24 / 8
Cycles per Reactor per Day (average/ peak) 6 / 8
React Time (min) (average/ peak) 120 / 90
Settling Time (min) (average/ peak) 60 / 30
SOR at ADF (kg/d) 3,760
Design Air Flow at ADF (m3/min) 33
Air Flow per Blower at ADF (m3/hr) 1,813
Volumetric BOD5 Loading (kg BOD /m³d) 0.1
MLSS (mg/L) 2,500
F/M Ratio 0.05
5.2.3 Disinfection
Flows from the SBR system will flow intermittently by gravity to the ultraviolet (UV) disinfection unit during
the decant cycle. The UV system must be able to accommodate the peak decant flows. The UV disinfection
unit will be installed in a single concrete channel located in the new process building. The channel will be
approximately 6.1 m long, 1.0 m wide, and 2.4 m deep. The UV system will consist of two banks of hybrid
MP/LPHO UV lamps. The lamps are oriented in a staggered inclined array and contain 12 lamps per bank
for a total of 24 lamps. The UV system includes an automated mechanical/chemical cleaning system, and
banks can be turned off automatically when not needed, if the UVT% and flow is monitored. In order for the
decant flow from the SBRs to flow by gravity through the UV system, the UV unit will be installed in the
basement of the process building. The maximum duty power draw for the system is 25.3 kW. The UV weir
height will set the hydraulic grade line for the rest of the treatment process.
Tidal height values are taken from the measurement station at nearby Glace Bay, since there is none in
New Waterford. The higher high water elevation at large tide for Glace Bay was 1.5m Chart Datum (CD)
which is equivalent to 1.0 m CGVD28 (geodetic datum) for 2018. The estimated extreme water level
values for 100 year and 50 year return periods were 2.5m CD (2.0 m CGVD28) and 2.4 m CD (1.9 m
CGVD28), respectively. In addition, a sea level rise of at least 1.0 m is likely to occur within the coming
century, even if the timeline remains uncertain (CBCL Limited, 2018). Therefore, the UV weir height
must be set at a minimum elevation above the extreme tide/surge level (100‐year return selected) with
an allowance for head losses over the weir and in the outfall of approximately 1.2 m, for a minimum UV
weir height of 4.2 m. The actual weir height can be higher than this to accommodate the site grade. The
design parameters for the UV disinfection system are summarized in the Table 5.5.
HEJV New Waterford WWTP Preliminary Design Brief 30
Table 5.5: UV Disinfection Design Summary
Parameter Design Value
Peak Flow Capacity (m3/d) 38,700
Number of Reactors (channels) 1
Number of Banks per Reactor 2
Number of Lamp per Bank 12
Total Number of Lamps 24
Effluent TSS (mg/L) <25
Minimum UV Transmission (%UVT) 60
Effluent Fecal Coliforms (MPN / 100 mL) 200
5.2.4 Sludge Management
Sludge must be removed from the treatment system and disposed of at an approved facility. Waste
activated sludge (WAS) from the SBR process will have a low solids concentration (less than 1% solids).
The WAS from the SBR will be pumped to an aerated sludge holding tank. The aeration will provide
mixing of the sludge as well as further Volatile Suspended Solids (VSS) reduction. The sludge holding
tank will be sized such that it will provide approximately 8.5 days of solids retention time (SRT). The
sludge holding tank volume will be provided in two cells. Supernatant from the aerated sludge tank will
be decanted back to the SBRs. However, minimal thickening of sludge is expected to occur in the sludge
tanks. Dewatering of sludge will be provided with a centrifuge. Design parameters for a centrifuge are
provided in Table 5.6.
Table 5.6: Aerated Sludge Holding Tank Design Summary
Parameter Design Value
No. of WAS pumps 2
Daily Sludge Production (kg/d) 710
Solids Content (%) 0.85
Daily Sludge Production (m3/d) 84
Total Storage Volume (m3) 840
No. of Cells 2
Tank Dimensions (per cell) (m) 7.2 x 10.6 x 5.5 (plus 1 m freeboard)
Dewatering
Sludge from the aerated sludge holding tank will be dewatered using a centrifuge. Centrifuges deliver
effective dewatering of WAS sludge from SBRs while reducing run hours and polymer use when compared
to other available technologies. Design parameters for the centrifuge are provided in Table 5.7.
HEJV New Waterford WWTP Preliminary Design Brief 31
Table 5.7: Sludge Dewatering Design Summary
Parameter Design Value
Sludge Flow (m3/hr) 16
Solids Loading Rate (kg/hr) 160
Polymer Consumption (kg/dry tonne) 12–15
Solids Capture (%) >95
Cake Solids (%) 18–22
5.3 Facilities Description
The WWTP project will include the following tanks and facilities:
Site access and parking.
Site fencing.
Lift station with overflow structure to outfall.
SBR tanks (2).
Aerated sludge holding tanks (2).
Process building.
Admin Building.
Yard piping.
Extension of outfall NW2, which will include replacement of existing outfall.
The process building will include the following:
Preliminary treatment area with:
- Two perforated plate fine screens with 6mm perforations and one screw
washer/compactor.
- Two vortex grit chambers with one grit classifier.
UV disinfection area.
Blower Room.
Mechanical and Electrical rooms.
Generator.
Sludge dewatering room with centrifuge, polymer area, and bin.
The Admin building will include the following:
Office space.
Lab.
Control room.
Locker room.
Lunch room.
Washrooms.
HEJV New Waterford WWTP Preliminary Design Brief 32
5.3.1 Civil and Site Work
Civil and site work will include grading, drainage and site improvements. An access road will be
constructed around the perimeter of the WWTP to provide vehicle access. The more frequently used
portions will be paved, and the less‐used portions will be gravelled. Security fencing will surround the
tanks and process building.
Retaining walls will be provided where required to allow the site to be developed within the area
between the restrictions posed by the cliff face (with a 42 m setback to allow for probable erosion with a
factor of safety, the wetland area, the mine workings and the nearby properties. We recommend that
the wetland area is delineated by a qualified wetland delineator to establish its precise area and
boundaries before detailed design commences. This area provides important ecological functions and
would require provincial permitting to build on; therefore, it is beneficial to avoid it if possible.
The Environmental Risk Assessment that was carried out for this system was completed on the basis of a
discharge through an outfall into the receiving environment about 150 m further out than the existing
450 mm diameter NW#2 outfall which ends at the shoreline; therefore, we have included for outfall
extension work. The new outfall would likely include a new HDPE outfall pipe, manholes as required,
stone mattress, concrete pipe anchors and armour stone protection. The existing overflow is sized for
the catchment it serves, and would need to be enlarged in order to accommodate the increased flow
from the community as a whole, including the peak flows from an SBR process, and overflows from Lift
Station 2. The approximate routing of the proposed treated wastewater outfall is shown on Drawing
C03 – Site Works Plan in Appendix C. We propose to work with NSE during the next stage of the project
to determine the requirements of the outfall before refining the outfall location and configuration.
5.3.2 Odour Control
Odours in the plant will be controlled by extracting the odorous air from the grit and screening area, and
the centrifuge and bin room, and then humidifying it and passing it through an odour control filter in the
yard. The odour control filter will consist of a bed of specially selected organic mulch that provides a
home for types of microorganisms that remove objectionable odour from the air.
5.3.3 Architectural
The exterior wall system of buildings will be erected of masonry cavity wall construction with polystyrene
cavity insulation. The inner walls will be reinforced concrete bearing block. The exterior veneer will be
face brick similar to the brick of CBRM’s other WWTPs. Interior doors and frames will be stainless, exterior
doors, windows and louvers shall be aluminium, colour anodized to match existing features. All new
buildings will have a hollow core or double tee concrete roofing system.
All required site railings for tanks, walkways, and stairs will be two rail all welded aluminium with a clear
anodized finish.
Interior concrete walls and concrete block walls of the buildings will be painted with an industrial epoxy
coating. Interior metal surfaces will be painted with epoxy coatings and exterior metal will be coated
with an ultraviolet resistant urethane finish. Process area ceilings will be painted. Process area floors
will be concrete, coated with a durable industrial floor coating.
HEJV New Waterford WWTP Preliminary Design Brief 33
5.3.4 Mechanical
Mechanical systems will be designed in accordance with NFPA 820, 2016 edition, which describes the
hazard classification of specific areas and processes and prescribes ventilation criteria for those areas.
Table 5.8 summarizes the proposed classification for new facilities. These are indicative only and may
change during detailed design.
Table 5.8: Classification of Building Areas
Location Classification
Preliminary Treatment Room Class 1 Zone 1
Mechanical and Electrical Rooms Unclassified
UV Room Unclassified
Blower Room Unclassified
Solids Handling Room Class 1 Zone 2
Odour Control Room Class 1 Zone 1
Admin Building Unclassified
Heating will be provided by electric unit heaters and electric duct heaters in central air handling units.
5.3.5 Electrical
3‐phase electrical service is available on Curran Street and will be extended to the site. An emergency
generator will be located in the Process Building.
5.3.6 Lighting
Exterior lighting will consist of building mounted luminaires illuminating areas immediately adjacent the
buildings, as well as pole mounted area lighting for access roadways and parking areas. Exterior lights
will be LED where available or to suit application. Exterior lighting fixtures shall be vandal resistant and
outdoor rated.
New pole mounted flood lights will be installed at the process tanks for maintenance purposes.
The interior lighting system will be designed for lighting performance and illuminance levels in
accordance with the Illuminating Engineering Society (IESNA) Lighting Handbook, 10th Edition. Interior
lights will be fluorescent, LED or metal halide to suit the application.
Emergency and exit lights will be installed along egress routing and around exit doors to meet the
requirements of the National and Provincial Building Codes.
5.3.7 Instrumentation
This section summarizes the functional requirements for the process control and instrumentation
system. It includes a narrative description of the instrumentation and control requirements.
HEJV New Waterford WWTP Preliminary Design Brief 34
Most unit processes in the treatment plant will be automated. There will be a main plant PLC that will
be used to control many of the unit processes. In addition to the main PLC, a local hand‐off‐auto
(H‐O‐A) switch will be required for most of the equipment. Some of the more complex unit processes
will be provided with their own individual PLCs including:
UV disinfection system.
SBRs.
Blowers.
Generator.
Centrifuge.
Each piece of equipment that is to be provided with a dedicated controller will be capable of operating
in either a manual or automatic mode (SCADA controlled) via a H‐O‐A switch.
Overview
Unit operations at the treatment plant will be monitored and controlled using a system of instruments,
equipment motors, PLCs, human machine interfaces (HMI), communications cable and hardware that is
integrated into a SCADA software program. The selection of Supervisory and Control Software as well as
the level one type of plant instrumentation will be made following the selection of a system integrator
and a review of options by plant operating personnel and the engineers.
The system will also be configured to allow an authorized operator to dial in and log on from a remote
location via laptop from their home. This will permit the Supervisor or duty operator to check plant
status, respond to after‐hours alarms, and to change equipment operation where appropriate.
In addition to the aforementioned monitoring and control terminals, there will be local control panels at
key locations using “soft panel” type HMIs (human/machine interface), which will permit the operator to
view process information and to take local control action. In some locations, where the only
requirement is to be able to stop a motor and to lock it out for maintenance, that capability will be
provided by hard‐wired controls at the motor starter.
The alarms integrated into the system will have audible and/or flashing light annunciation in the plant
during regular hours, and call‐out by telephone and/or email after hours with a user‐configurable
sequential call priority list.
Headworks
The Headworks consist of fine screening and a vortex grit chamber. All the equipment will be controlled
by the main PLC. Each piece of equipment will be monitored for status and faults in addition to the
alarms for high and low levels in the influent channels which will be registered on the central control
computers and monitors.
HEJV New Waterford WWTP Preliminary Design Brief 35
SBR System
Effluent from preliminary treatment will be split between the SBR tanks via weirs.
The SBR and sludge blowers will be installed in the Process Building. The SBR blowers will discharge to a
common air header which will have a dedicated take off for each SBR. Blower operation will be
controlled by the SBR control system. The digester blower will discharge to a common air header which
will have a dedicated take off for the sludge holding tank cell.
The air headers will feed the fine bubble diffusers arranged along the bottom of the SBRs. A separate
header will feed the fine bubble diffusers arranged along the bottom of the aerated sludge holding
tanks. Dissolved oxygen will be monitored in the SBR tanks.
An air flow meter in the supply header will indicate, totalize, and record the air flow to the plant. The
dissolved oxygen levels for each reactor will be indicated and recorded on the central SCADA system.
Blower operating status, header pressure and inlet valve positions as well as supply line pressure will be
indicated on the central computer system. The blowers will also be equipped with sensors and alarms
for surge, vibration, temperature and general faults, which will register at the central control.
Effluent will be removed from the SBR tanks via a solids excluding decanter. Flow through the decanter
will be automatically controlled via a valve by the SBR control system.
Waste Activated Sludge
The WAS will be pumped from the SBRs to the aerated sludge holding tanks automatically using WAS
pumps which will be controlled by the SBR control system. The WAS flow will be measured by magnetic
flow meters installed on the suction side of the pumps.
Effluent Disinfection
Ultraviolet Disinfection will be used to achieve disinfection limits for fecal coliform prior to discharge.
The UV manufacturer will provide a PLC to control the UV system. The UV PLC will be compatible with
the central station. UV dose will be controlled by plant flow and percent UVT. Monitoring and
recording of UV intensity, general alarms and low level, high levels alarms will be provided. Automatic
wiping will be controlled on timer or by monitoring UV intensity.
Centrifuge
The sludge feed rate to the centrifuge equipment will be set to maintain the sludge inventory in the
holding tanks within a set band. The centrifuge PLC communicates with the sludge feed pumps and
polymer make‐down system and adjusts sludge feed and polymer dosing pump rates to suit the
centrifuge throughput.
HEJV New Waterford WWTP Preliminary Design Brief 36
5.4 Staffing Requirements
Staffing at wastewater treatment plants will vary depending on a number of factors including the
following:
Plant classification (I, II, III or IV).
Plant size and treatment capacity.
Laboratory requirements.
Complexity of the unit processes.
Level of automation.
Maintenance of peripheral facilities such pumping stations, collection systems, septage
receiving, etc.
Sensitivity of the receiving waters.
Variation in flows and loads to the plant i.e. industrial, municipal, storm water component.
Based on the Points Classification System in the Atlantic Canadian Guidelines (Appendix A), the
proposed WWTP has been determined to be in the range of 49 to 58 points depending upon
interpretation. A fair interpretation may lean towards the high end of the range since odour control will
be part of the final plant solution. Odour control adds a certain level of complexity to the operations;
however, the guidelines do not make provisions for this. Since Class II plants are defined as having 31–
56 points, the WWTP will be ranked as at least a Class II level treatment plant by the regulators, and
possibly a Class III level treatment plant.
According to the guidelines, a Class II or Class III plant designed for an average daily flow of 8,000 m3/day
will require approximately 9,000–11,000 man‐hours per year to operate, or about 6 fulltime employees.
It is also important to consider staffing levels at other plants operating in the region. Secondary
treatment plants at Millidgeville in Saint John (10,000 m³/day) and Fredericton WWTP (18,000 m³/day)
each have seven fulltime staff, consisting of operators, laboratory technician(s) and maintenance
personnel. The Colchester County WWTP near Truro and the East River Pollution Abatement System in
New Glasgow treat between 16,000 and 18,000 m³/day on average. Each of these plants has five
fulltime staff.
At start‐up, it is suggested that CBRM be prepared to staff the New Waterford WWTP with a minimum
of 4 fulltime staff. It is likely that staff at the proposed facility will be responsible for operating and
maintaining raw sewage lift stations.
HEJV New Waterford WWTP Preliminary Design Brief 37
CHAPTER 6 PROJECT COSTS
6.1 Opinion of Probable Capital Costs
An opinion of probable capital cost for the recommended treatment process option is presented in
Table 6.1, detailed on the next page. Please note that the costs of interception and pumping are extra
and are detailed in New Waterford Collection System Pre‐Design Brief (Dillon Consulting Limited, 2019).
Please note that the capital costs given are in 2019 dollars, and would typically be inflated at a rate of
approximately 3% per year going forward to the intended construction year (or indexed using the actual
construction cost index ratio if calculating the probable construction cost at a specific point after 2019).
Table 6.1
6.2 Opinion of Annual Operating Costs
An annual operating cost estimate for the recommended treatment process option is presented in
Table 6.2.
Table 6.2: Operating Cost Estimate
Category Annual Operation Cost
Staffing $400,000
Power $111,000
Chemicals $20,000
Sludge Disposal $130,000
Maintenance Allowance $21,000
Total $682,000
Project Manager:D. McLean
Est. by: S.E./H.S.Checked by: A Thibault
PROJECT No.:187116 (Dillon)
182402.00 (CBCL)
UPDATED:May 7, 2019
1.0 2,095,000$
allow 1 500,000$ 500,000$
allow 10% 1,594,900$
2.0 2,501,000$
m2 8,317 5$ 41,585$
m3 excavated 27,144 20$ 542,878$
m3 1,928 40$ 77,122$
tonne 352 115$ 40,432$
tonne 907 25$ 22,683$
tonne 1,512 22$ 33,268$
m 91 100$ 9,073$
Retaining Walls (MSE)m²165 625$ 103,125$
m 76 350$ 26,463$
m 87 725$ 63,035$
m98 60$ 5,898$
ea.4 8,000$ 30,244$
m 265 100$ 26,463$
allow 1 8,990$ 8,990$
allow 1 50,000$ 50,000$
allow 1 20,000$ 20,000$
allow 1 1,400,000$ 1,400,000$
3.0 4,563,000$
m3 of baseslab 185 700$ 129,640$
m3 of baseslab 1,564 900$ 1,407,420$
m3 of concrete 95 700$ 66,528$
m3 of concrete 1,562 1,600$ 2,499,552$
m3 of concrete 50 1,000$ 50,000$
allow 10% 410,314$
4.0 342,000$
m2 wall area 650 170$ 110,568$
m2 wall area 578 400$ 231,120$
5.0 448,000$
m2 building area 620 100$ 62,000$
m2 building area 620 430$ 266,848$
m2 building area 620 160$ 99,200$
allow 20,000$
6.0 264,000$
m2 building area 620 40$ 24,800$
m2 building area 740 65$ 48,100$
m2 building area 740 50$ 37,000$
m2 building area 740 54$ 39,812$
m2 building area 170 15$ 2,550$
each 6 2,650$ 15,900$
each 15 1,100$ 16,634$
each 2 6,000$ 12,000$
each 6 3,500$ 21,000$
m2 building area 620 75$ 46,500$
7.0 2,859,000$
each 1.5 230,000$ 345,000$
each 1.5 247,000$ 370,500$
each 1 933,333$ 933,333$
each 1 380,115$ 380,115$
allow 1 580,081$ 580,081$
allow 1 250,000$ 250,000$
8.0 2,031,000$
m2 building area 740 700$ 518,000$
allow 30% of equipment 648,505$
allow 40% of equipment 864,673$
9.0 2,941,000$
allow 15% of project cost 1,951,200$
allow 3% of project cost 390,240$
allow 600,000$
18,044,000$
A 25% 4,511,000$
B 12% 2,165,000$
C 300,000$
25,020,000$
15%3,753,000$
28,773,000$
Note 1 A Design Development Contingency is to allow for necessary increases of qty's; construction costs; as the work is better defined
Note 2 A Construction Contingency is to allow for cost of additional work over and above the contract Awarded price.
Note 3 The Escalation/Inflation allowance is for increases in construction costs from time the budget to Tender Call
Note 4 The Location Factor is for variances between constr. costs at the location of the project & historical costs data
Form CBCL 034.Rev 0
EST. QUANTITY
Wastewater Treatment System Costs Only
Table 6.1
PREPARED FOR:OPINION OF PROBABLE COST, CLASS 'C'
Preliminary
Cape Breton Regional MunicipalityNew Waterford, NS
Overhead rolling door (3m wide)
Foundation and Exterior Building Walls
Outfall Upgrade
ITEM / No.DESCRIPTION UNIT
Reinstatement
Gravel (beneath slabs)
Ditching
600 mm dia Concrete Cl 65 Storm sewer
Asphalt
Type 1
Type 2
Curb
150 mm dia D.I. Piping
Dewatering
Sediment Control
Manholes
UNIT COST Total
Site Works
Carpentry, Assessories and Fixtures
Louvers
Painting
Epoxy Coating
Floor Finishes (Lab, Office, Admin Area)
Windows (exterior ‐ single)
Doors (single swing steel)
Baseslabs (tanks)
Slab on Grade (building)
Miscellaneous Concrete Items
Exterior Masonry
Metals & Roofing
Metal Railings, Stairs, Grating, Hatches
Beams and Columns
Odour Control
UV Disinfection System
Double swing FRP doors
Other Interior Finishes, Misc
Process Equipment Supply
SBR Equipment
Mobilization, Bonds, Insurance, P.C. Mngmt
Contractor Overhead & Fees
Foundations and Tank Walls
Lean Concrete
Site Preparation
Excavation
Grit Removal
Finishes/Doors/Windows
Masonry
Interior Masonry
Chainlink Fence and Gates
Fine Screening
Concrete
Roof
Miscellaneous Metals Items
Mechanical
HVAC and Plumbing
Electrical
Power Supply & Distribution
Process Mechanical
Instrumentation & Control
Process Installation
THIS OPINION OF PROBABLE COSTS IS PRESENTED ON THE BASIS OF EXPERIENCE, QUALIFICATIONS, AND BEST JUDGEMENT. IT HAS BEEN PREPARED IN ACCORDANCE WITH ACCEPTABLE
PRINCIPLES AND PRACTICES. MARKET TRENDS, NON‐COMPETITIVE BIDDING SITUATIONS, UNFORSEEN LABOUR AND MATERIAL ADJUSTMENTS AND THE LIKE ARE BEYOND THE CONTROL OF
HEJV. AS SUCH WE CANNOT WARRANT OR GUARANTEE THAT ACTUAL COSTS WILL NOT VARY FROM THE OPINION PROVIDED.
Taxes (HST)
TOTAL DIRECT & INDIRECT CONSTRUCTION COST (Exluding Contingencies and Allowances)
TOTAL CONSTRUCTION & DESIGN COST without HST
TOTAL CONSTRUCTION & DESIGN COST with HST
Land Purchase
Generator
CONTINGENCIES and ALLOWANCES
Construction Contingency
General Conditions
Engineering
Sludge Dewatering
HEJV New Waterford WWTP Preliminary Design Brief 39
6.3 Opinion of Annual Capital Replacement Fund Contributions
The CBRM wishes to create a Capital Replacement Fund to which annual contributions would be made
to prepare for replacement of the wastewater assets at the end of their useful life. The calculation of
annual contributions to this fund involves consideration of such factors as the type of asset, the asset
value, the expected useful life of the asset, and the corresponding annual depreciation rate for the
asset, as per the accounting practices for asset depreciation and Depreciation Funds recommended in
the Water Utility Accounting and Reporting Handbook (Nova Scotia Utility and Review Board, 2013). In
consideration of these factors, Table 6.3 provides an estimation of the annual contributions to a capital
replacement fund for the proposed new wastewater treatment system infrastructure. This calculation
also adds the same contingency factors used in the calculation of the Opinion of Probable Capital Cost,
to provide an allowance for changes during the design and construction period of the WWTP. The actual
Annual Capital Replacement Fund Contributions will be calculated based on the final constructed asset
value, the type of asset, the expected useful life of the asset, and the corresponding annual depreciation
rate for the asset type.
Table 6.3: Annual Capital Replacement Fund Contributions
Description of Asset Asset Value
Asset
Useful Life
Expectancy
(Years)
Annual
Depreciation
Rate (%)
Annual Capital
Replacement
Fund
Contribution
Treatment Linear Assets (Outfall
and Yard Piping, Manholes and
Other)
$2,000,000 75 1.3% $27,000
Treatment Structures (Concrete
Chambers, etc.) $7,500,000 50 2.0% $150,000
Treatment Equipment
(Mechanical / Electrical, etc.) $8,600,000 20 3.3% $430,000
Subtotal $18,100,000 ‐ ‐ $607,000
Construction Contingency (Subtotal x 25%): $152,000
Engineering (Subtotal x 12%): $73,000
Opinion of Probable Annual Capital Replacement Fund Contribution: $832,000
Table Notes
1. Annual contributions do not account for annual inflation.
2. Costs do not include applicable taxes.
HEJV New Waterford WWTP Preliminary Design Brief 40
CHAPTER 7 REFERENCES
ABL Environmental Consultants Limited. (2006). Atlantic Canada Wastewater Guidelines Manual for
Collection, Treatment and Disposal. Environment Canada.
CBCL Limited. (2018). Glace Bay Harbour Coastal Study – Final Report. Halifax: CBCL Limited.
Harbour Engineering Joint Venture. (2019). New Waterford Collection System Pre‐Design Brief.
Metcalf & Eddy, Inc. (2003). Wastewater Engineering: Treatment and Reuse. New Delhi: Tata
McGraw‐Hill.
Nova Scotia Utility and Review Board. (2013). Water Utility Accounting and Reporting Handbook.
UMA Engineering Limited. (1994). Industrial Cape Breton Wastewater Characterization Programme
– Phase II.
HEJV Appendices
APPENDIX A
Flow Meter Data
0
10
20
30
40
50
60
70
800
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
Fe
b
-
2
7
Ma
r
-
0
3
Ma
r
-
0
7
Ma
r
-
1
1
Ma
r
-
1
5
Ma
r
-
1
9
Ma
r
-
2
3
Ma
r
-
2
7
Ma
r
-
3
1
Ap
r
-
0
4
Ap
r
-
0
8
Ap
r
-
1
2
Ap
r
-
1
6
Ap
r
-
2
0
Ap
r
-
2
4
Ap
r
-
2
8
Ma
y
-
0
2
Ma
y
-
0
6
Ma
y
-
1
0
Ma
y
-
1
4
Pr
e
c
i
p
i
t
a
t
i
o
n
Fl
o
w
(
m
3/d
)
NW2 -Spring 2018
Snow on Ground (cm)Rain (mm)Metered Flow
0
10
20
30
40
50
60
70
800
5,000
10,000
15,000
20,000
25,000
Aug-01 Aug-03 Aug-05 Aug-07 Aug-09 Aug-11 Aug-13 Aug-15 Aug-17 Aug-19 Aug-21 Aug-23
Ra
i
n
(
m
m
)
Me
t
e
r
e
d
F
l
o
w
(
m
3/d
)
NW2 - Summer 2018
0
10
20
30
40
50
60
70
800
5,000
10,000
15,000
20,000
25,000
30,000
Aug-01 Aug-03 Aug-05 Aug-07 Aug-09 Aug-11 Aug-13 Aug-15 Aug-17 Aug-19
Pr
e
c
i
p
i
t
a
t
i
o
n
(
m
m
)
Me
t
e
r
e
d
F
l
o
w
(
m
3/d
)
NW1 - Summer 2018
HEJV Appendices
APPENDIX B
Environmental Risk Assessment
HEJV Appendices
APPENDIX C
Preliminary Design Drawings
j o i n t v e n t u r e
C01
CONCEPT
DRAWING
j o i n t v e n t u r e
C02
CONCEPT
DRAWING
j o i n t v e n t u r e
C03
CONCEPT
DRAWING
j o i n t v e n t u r e
P01
CONCEPT
DRAWING
HEJV New Waterford Wastewater System Pre‐Design Summary Report Appendices
APPENDIX C
New Waterford Environmental Risk
Assessment
182402.00 ● Report ● April 2020
New Waterford Wastewater Treatment Plant
Environmental Risk Assessment
Final Report
Prepared by:
Prepared for:
March 2020
Final April 22, 2020 Darrin McLean Karen March Holly Sampson
Revised Draft – Revision 1 January 7, 2019 Darrin McLean Karen March Holly Sampson
Draft for Review October 10, 2018 Darrin McLean Karen March Holly Sampson
Issue or Revision Date Issued By: Reviewed By: Prepared By:
This document was prepared for the party indicated
herein. The material and information in the
document reflects HE’s opinion and best judgment
based on the information available at the time of
preparation. Any use of this document or reliance
on its content by third parties is the responsibility of
the third party. HE accepts no responsibility for any
damages suffered as a result of third party use of
this document.
182402.00
March 27, 2020
182402.00 RE 001 FINAL WWTP ERA NEW WATERFORD.DOCX 2020-04-22/mk
ED: 22/04/2020 13:18:00/PD: 22/04/2020 13:18:00
April 22, 2020
Matt Viva, P.Eng.
Manager Wastewater Operations
Cape Breton Regional Municipality (CBRM)
320 Esplanade,
Sydney, NS B1P 7B9
Dear Mr. Viva:
RE: New Waterford Wastewater Treatment Plant ERA – Final Report
Enclosed, please find a copy of the Environmental Risk Assessment (ERA) Report
for the New Waterford Wastewater Treatment Plant (WWTP).
The report outlines Environmental Quality Objectives (EQOs) for all parameters
of potential concern listed in the Standard Method for a “medium” facility that
were detected in the wastewater. Environmental Discharge Objectives (EDOs)
were also calculated for all parameters of potential concern that were detected
in the wastewater and for which an Environmental Quality Objective (EQO) was
identified.
If you have any questions or require clarification on the content presented in
the attached report, please do not hesitate to contact us.
Yours very truly,
Harbour Engineering
Prepared by: Reviewed by:
Holly Sampson, M.A.Sc., P.Eng. Karen March, M.Sc.
Intermediate Chemical Engineer Environmental Scientist
Direct: 902-539-1330 Phone: 902-450-4000
E-Mail: hsampson@cbcl.ca E-Mail: kmarch@dillon.ca
Project No: 182402.00 (CBCL)
187116.00 (Dillon)
March 27, 2020
Harbour Engineering Joint Venture New Waterford WWTP ERA i
Contents
CHAPTER 1 Background and Objectives ................................................................................... 1
1.1 Introduction .................................................................................................................. 1
1.2 Background ................................................................................................................... 1
1.3 Facility Description ........................................................................................................ 2
CHAPTER 2 Initial Wastewater Characterization ...................................................................... 5
2.1 Substances of Potential Concern .................................................................................. 5
2.1.1 Whole Effluent Toxicity ..................................................................................... 7
2.2 Wastewater Characterization Results .......................................................................... 7
CHAPTER 3 Environmental Quality Objectives ....................................................................... 12
3.1 Water Uses .................................................................................................................. 12
3.2 Ambient Water Quality ............................................................................................... 13
3.3 Physical/ Chemical/ Pathogenic Approach ................................................................. 19
3.3.1 General Chemistry/ Nutrients ........................................................................ 19
3.3.2 Metals ............................................................................................................. 24
3.3.3 E. coli ............................................................................................................... 26
3.3.4 Summary ......................................................................................................... 27
CHAPTER 4 Mixing Zone Analysis ........................................................................................... 30
4.1 Methodology ............................................................................................................... 30
4.1.1 Definition of Mixing Zone ............................................................................... 30
4.1.2 Site Summary .................................................................................................. 32
4.1.3 Far-Field Modeling Approach and Inputs ....................................................... 32
4.1.4 Modeled Effluent Dilution .............................................................................. 35
CHAPTER 5 Effluent Discharge Objectives .............................................................................. 38
5.1 The Need for EDOs ...................................................................................................... 38
5.2 Physical/ Chemical/ Pathogenic EDOs ........................................................................ 38
5.3 Effluent Discharge Objectives ..................................................................................... 38
CHAPTER 6 Compliance Monitoring ....................................................................................... 42
CHAPTER 7 References .......................................................................................................... 43
Appendices
A Laboratory Certificates
Harbour Engineering Joint Venture New Waterford WWTP ERA 1
CHAPTER 1 BACKGROUND AND OBJECTIVES
1.1 Introduction
Harbour Engineering (HE) was engaged by the Cape Breton Regional Municipality (CBRM) to complete
an Environmental Risk Assessment (ERA) for the proposed New Waterford Wastewater Treatment Plant
(WWTP). As this is a proposed WWTP that has not yet been designed, this ERA was completed with the
objective that it serve as a tool to establish effluent criteria for the design of a new WWTP. For this
reason, the ERA was completed without the frequency of testing required by the Standard Method
outlined in Technical Supplement 3 of the Canada-wide Strategy for the Management of Municipal
Wastewater Effluent (Standard Method) for initial effluent characterization. With the exception of the
initial effluent characterization sampling frequency, the ERA was otherwise completed in accordance
with the Standard Method.
1.2 Background
The Canada-wide Strategy (CWS) for the Management of Municipal Wastewater Effluent was adopted
by the Canadian Council of Ministers of the Environment (CCME) in 2009. The Strategy is focused on
two (2) main outcomes: Improved human health and environmental protection; and improved clarity
about the way municipal wastewater effluent is managed and regulated. The Strategy requires that all
wastewater facilities discharging effluent to surface water meet the following National Performance
Standards (NPS) as a minimum:
• Carbonaceous Biochemical Oxygen Demand for five days (CBOD5) – 25 mg/L;
• Total Suspended Solids (TSS) – 25 mg/L; and
• Total Residual Chlorine (TRC) – 0.02 mg/L.
The Wastewater Systems Effluent Regulations (WSER) came into effect in 2012 under the Fisheries Act.
The WSER include the above NPS as well as the following criteria:
• Un-ionized ammonia - 1.25 mg/L, expressed as nitrogen (N), at 15°C ± 1°C.
The CWS requires that facilities develop site-specific EDOs to address substances not included in the NPS
that are present in the effluent. EDOs are the substance concentrations that can be discharged in the
effluent and still provide adequate protection of human health and the environment. They are
established by conducting a site-specific ERA. The ERA includes characterization of the effluent to
determine potential substances of concern, and characterization of the receiving water to determine
Harbour Engineering Joint Venture New Waterford WWTP ERA 2
beneficial water uses, ambient water quality, assimilative capacity, and available dilution. A compliance
monitoring program is then developed and implemented to ensure adherence to the established EDOs
for the facility.
1.3 Facility Description
The proposed New Waterford Wastewater Treatment Plant (WWTP) will be constructed at the end
of Mahon Street, near the Barachois. Treated effluent will be discharged to the Atlantic Ocean
(Figure 1.2) at the location of the existing NW2 outfall. The service population of New Waterford is
7,420 people in 3,735 residential units.
Figure 1.1 Site Location
Harbour Engineering Joint Venture New Waterford WWTP ERA 3
Figure 1.2 WWTP Location
The theoretical domestic wastewater flow is an average of 2,523 m3/day with a peak of 7,821
m3/day based on a per capita flow of 340 L/person/day and a peaking factor of 3.1 calculated using
the Harmon formula.
Flowmeters were installed in summer of 2018 at the following location:
• Upstream of NW2 outfall (located in field area behind Civic #180 Mahon St); and
• Upstream of NW1 outfall (Southeast corner of Mahon St and Bay Avenue intersection).
Flowmeters were previously installed in spring of 2018 at the following locations:
• Upstream of NW2 outfall (located in field area behind Civic #180 Mahon St).
Wastewater flows were also previously metered by UMA Engineering in 1992 at three locations in
the collection system.
The summer average dry weather flows (ADWF) upstream of NW2 and NW1 were 321 L/p/d for
1,046 people and 1154 L/p/d for 3017 people, respectively. The combined per capita ADWF for
summer 2018 was 1050 L/p/d. With a total service population of 7,420 people, this gives an ADWF
(summer) of approximately 7,800 m3/day. For comparison, the 1992 ADWF values for NW2 and
NW1 were 280 L/p/d and 912 L/p/d, respectively. There was a significant amount of dry weather
infiltration upstream of NW1 during the summer. As summer months typically have seasonally
lower levels of dry weather infiltration due to a lower groundwater table, it is possible that there
may be even higher levels of dry weather infiltration in the spring.
The spring ADWF upstream of NW2 had a much larger ADWF of 1054 L/p/day (compared to 321
L/p/day in the summer). NW1 was not metered in the spring. This indicates that there are
seasonally high dry weather flows in the spring for NW2, and year-round high dry weather flows for
NW1 (although they may be even higher in spring).
For the purpose of the draft ERA, the average daily flow will be assumed to be 7,800 m3/day (1050
L/p/day), based on the per capita dry weather flows metered during the summer. However, it is
expected that inflow and infiltration (I&I) reduction will be required as part of the project to reduce
Harbour Engineering Joint Venture New Waterford WWTP ERA 4
the flows to the WWTP. The preliminary design study was completed assuming an average daily
flow of 8,000 m3/day. If the future design flow is significantly different than the ERA assumed flow,
ERA conclusions will be re-assessed at that time. The design flows do not account for growth.
CBRM has a declining population so increased flows due to population growth are not expected.
CBRM’s wastewater collection systems have significant inflow and infiltration (I&I), and CBRM plans
to implement an I&I reduction program.
Harbour Engineering Joint Venture New Waterford WWTP ERA 5
CHAPTER 2 INITIAL WASTEWATER CHARACTERIZATION
2.1 Substances of Potential Concern
An initial characterization program covering a one-year period is typically required by the Standard
Method to describe the effluent and identify substances of concern. As there is no existing WWTP
for this system, and the ERA is being conducted for the purpose of determining effluent objectives
for the design of a new WWTP, one sample event was completed for each of the two outfalls.
Sample results for some of the parameters of potential concern were also available from three-years
of sampling conducted by CBRM from 2015 through 2017 at the NW1 outfall, one sample event
conducted by Dillon Consulting in 2014 at each of the two outfalls, and samples collected by UMA
Engineering in 1992 at the NW2 outfall and two locations upstream of the NW1 outfall. Substances
of potential concern are listed in the Standard Method based on the size category of the facility.
The proposed design capacity of the new WWTP will be finalized during the pre-design study, but for
the purposes of the draft ERA, an average annual flow of 7,800 m3/day will be assumed based on a
per capita flow of 1050 L/p/day. Therefore, the WWTP is classified as a “medium” facility based on
an average daily flow rate that is between 2,500 and 17,500 m3/day.
The substances of potential concern for a “medium” facility, as per the Standard Method, are
detailed in Table 2.1. There were no additional substances of concern identified to be monitored as
industrial input does not exceed 5% of total dry weather flow in the sewer shed, on an annual
average basis. There is one hospital, but the flows are expected to be much less than 5% of the
wastewater flow for the system.
Harbour Engineering Joint Venture New Waterford WWTP ERA 6
Table 2.1 – Substances of Potential Concern for a Medium Facility
Test Group Substances
General Chemistry
/ Nutrients
Fluoride
Nitrate
Nitrate + Nitrite
Total Ammonia Nitrogen
Total Kjeldahl Nitrogen (TKN)
Total Phosphorus (TP)
Total Suspended Solids (TSS)
Carbonaceous Biochemical Oxygen Demand (CBOD5)
Total Residual Chlorine (TRC)
Chemical Oxygen Demand (COD)
Cyanide (total)
pH
Temperature
Metals
Aluminum, barium, beryllium, boron, cadmium, chromium, cobalt, copper, iron,
lead, manganese, molybdenum, nickel, silver, strontium, thallium, tin, titanium,
uranium, vanadium, zinc as well as arsenic, antimony, selenium and mercury
Pathogens E. coli (or other pathogen, as directed by the jurisdiction)
Organochlorine
Pesticides
Alpha-BHC, endosulfin (I and II), endrin, heptachlor epoxide, lindane (gamma-
BHC), mirex, DDT, methoxychlor, aldrin, dieldrin, heptachlor, a-chlordane and g-
chlordane, toxaphene
Polychlorinated
Biphenyls (PCBs) Total PCBs
Polycyclic Aromatic
Hydrocarbons
(PAHs)
Acenaphthene, acenapthylene, anthracene, benzo(a)anthracene,
benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene,
benzo(k)fluoranthene, chrysene, dibenz(a,h)anthracene, fluoranthene, fluorene,
indeno(1,2,3-cd)pyrene, methylnaphthalene, naphthalene, phenanthrene, pyrene
Volatile Organic
Compounds (VOCs)
Benzene, bromodichloromethane, bromoform, carbon tetrachloride,
chlorobenzene, chlorodibromomethane, chloroform, 1,2-dichlorobenzene, 1,4-
dichlorobenzene, 1,2-dichloroethane, 1,1-dichloroethene, dichloromethane,
ethylbenzene, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane,
tetrachloroethene, toluene, trichloroethene, vinyl chloride, m/p-xylene, o-xylene
Phenolic
Compounds
2,3,4,6-tetrachlorophenol, 2,4,6-trichlorophenol, 2,4-dichlorophenol,
pentachlorophenol
Surfactants Non-ionic surfactants and anionic surfactants (others may be added by the
jurisdiction)
Harbour Engineering Joint Venture New Waterford WWTP ERA 7
2.1.1 Whole Effluent Toxicity
Wastewater effluent potentially contains a variety of unknown or unidentified substances for which
guidelines do not exist. In order to adequately protect against these unknown substances, Whole
Effluent Toxicity (WET) tests are typically conducted to evaluate acute (short-term) and chronic (long-
term) effects.
The Standard Method requires the following toxicity tests be conducted quarterly:
• Acute toxicity – Rainbow Trout and Daphnia magna; and
• Chronic Toxicity – Ceriodaphnia dubia and Fathead Minnow.
A draft for discussion Mixing Zone Assessment and Report Template, dated July 6, 2016 that was
prepared by a committee of representatives of the environment departments in Atlantic Canada noted
that only Ceriodaphnia dubia testing is required for chronic toxicity. If the test does not pass, a fathead
minnow test is required.
As the wastewater in this system is currently untreated, and the purpose of the ERA is to determine
effluent discharge objectives for the design of a new WWTP, no WET tests were conducted at this time.
2.2 Wastewater Characterization Results
The results of the initial wastewater characterization program completed by HE are summarized in
Tables 2.2 through 2.6. One sample was collected for each of the two outfalls in the system as part
of the initial wastewater characterization study.
Table 2.2 – Initial Wastewater Characterization Results – General Chemistry
Parameter Outfall
NW1 NW2
CBOD5 (mg/L) 93 140
COD (mg/L) 170 260
Total NH3-N (mg/L) 2.3 3.1
TSS (mg/L) 110 60
TP (mg/L) 1.4 1.6
TKN (mg/L) 9.9 10
pH 6.59 6.58
Un-ionized NH3 (mg/L)(1) 0.0025 0.0032
E. coli (MPN/100mL) 1000000 >240000
Fluoride (mg/L) 0.16 0.17
Nitrate (mg/L) 0.32 <0.050
Nitrite (mg/L) 0.13 0.3
Nitrate + Nitrite (mg/L) 0.45 0.3
Total Cyanide (mg/L) 0.0035 0.0035
Note: (1) The value of unionized ammonia was determined in accordance with the formula in the WSER, the
concentration of total ammonia in the sample, and the pH of the sample.
Harbour Engineering Joint Venture New Waterford WWTP ERA 8
Table 2.3 – Initial Wastewater Characterization Results – Metals (mg/L)
Parameter Outfall
NW1 NW2
Aluminum 0.43 0.6
Antimony <0.0010 <0.0010
Arsenic <0.0010 <0.0010
Barium 0.039 0.039
Beryllium <0.0010 <0.0010
Boron <0.050 0.12
Cadmium 0.00032 0.0003
Chromium <0.0010 <0.0010
Cobalt 0.0008 0.0032
Copper 0.014 0.012
Iron 0.73 0.66
Lead 0.0012 0.0012
Manganese 0.4 1.1
Molybdenum <0.0020 <0.0020
Nickel 0.0038 0.011
Selenium <0.0010 <0.0010
Silver <0.00010 <0.00010
Strontium 0.09 0.14
Thallium <0.00010 <0.00010
Tin <0.0020 <0.0020
Titanium 0.013 <0.020
Uranium 0.00014 0.00013
Vanadium <0.0020 <0.0020
Zinc 0.077 0.079
Mercury <0.013 <0.013
Harbour Engineering Joint Venture New Waterford WWTP ERA 9
Table 2.4 – Initial Wastewater Characterization Results – VOCs (µg/L)
Parameter Outfall
NW1 NW2
1,2-dichlorobenzene <0.50 <0.50
1,4-dichlorobenzene <1.0 <1.0
Chlorobenzene <1.0 <1.0
1,1,2,2-tetrachloroethane <0.50 <0.50
1,1-Dichloroethylene <0.50 <0.50
1,2-dichloroethane <1.0 <1.0
1,2-Dichloropropane <0.50 <0.50
Benzene <1.0 <1.0
Bromodichloromethane 1.1 1.4
Bromoform <1.0 <1.0
Carbon Tetrachloride <0.50 <0.50
Chloroform 2.1 2.3
Dibromochloromethane <1.0 <1.0
Ethylbenzene <1.0 <1.0
Methylene Chloride (Dichloromethane) <3.0 <3.0
o-xylene <1.0 <1.0
m/p-xylene <2.0 <2.0
Tetrachloroethene (Tetrachloroethylene) <1.0 <1.0
Toluene <1.0 <1.0
Trichloroethene (Trichloroethylene) <1.0 <1.0
Vinyl Chloride <0.50 <0.50
Harbour Engineering Joint Venture New Waterford WWTP ERA 10
Table 2.5 – Initial Wastewater Characterization Results – PCBs, Phenols, PAHs
Parameter Outfall
NW1 NW2
Total PCBs (µg/L) <0.05 <0.3
Phenols (mg/L) 0.0084 0.0094
1-Methylnaphthalene (µg/L) <0.050 <0.050
2-Methylnaphthalene (µg/L) <0.050 <0.050
Acenaphthene (µg/L) <0.030 <0.010
Acenaphthylene (µg/L) <0.010 <0.010
Anthracene (µg/L) <0.010 <0.010
Benzo(a)anthracene (µg/L) 0.01 <0.010
Benzo(a)pyrene (µg/L) <0.010 <0.010
Benzo(b)fluoranthene (µg/L) 0.011 <0.010
Benzo(g,h,i)perylene (µg/L) <0.010 <0.010
Benzo(k)fluoranthene (µg/L) <0.010 <0.010
Chrysene (µg/L) 0.01 <0.010
Dibenz(a,h)anthracene (µg/L) <0.010 <0.010
Fluoranthene (µg/L) 0.028 <0.010
Fluorene (µg/L) 0.011 <0.010
Indeno(1,2,3-cd)pyrene (µg/L) <0.010 <0.010
Naphthalene (µg/L) <0.20 <0.20
Phenanthrene (µg/L) 0.026 0.022
Pyrene (µg/L) 0.021 <0.010
Table 2.6 – Initial Wastewater Characterization Results – Organochlorine Pesticides (µg/L)
Parameter Outfall
NW1 NW2
Aldrin <0.005 <0.03
Dieldrin <0.005 <0.03
a-Chlordane <0.005 <0.03
g-Chlordane <0.005 <0.03
o,p-DDT <0.005 <0.03
p,p-DDT <0.005 <0.03
Lindane <0.003 <0.02
Endosulfan I (alpha) <0.005 <0.03
Endosulfan II (beta) <0.005 <0.03
Endrin <0.005 <0.03
Heptachlor <0.005 <0.03
Heptachlor epoxide <0.005 <0.03
Methoxychlor <0.01 <0.07
alpha-BHC <0.005 <0.03
Mirex <0.005 <0.03
Toxaphene <0.2 <1
DDT+ Metabolites <0.005 <0.03
Harbour Engineering Joint Venture New Waterford WWTP ERA 11
Table 2.7 – Historical Wastewater Characterization Samples
Location Parameter Average Number of Samples
NW1
TSS (mg/L) 74.2 106
CBOD5 (mg/L) 104.7 106
Total Ammonia (mg/L) 6.6 26
pH (mg/L) 7.0 56
Un-ionized Ammonia (mg/L) 0.019 27
Alkalinity (mg/L) 93.50 5
TKN (mg/L) 41.99 5
Total Phosphorus (mg/L) 2.93 5
NW2
TSS (mg/L) 68.5 26
CBOD5 (mg/L) 103.9 26
pH (mg/L) 7.3 25
Un-ionized Ammonia (mg/L) 0.009 1
Alkalinity (mg/L) 110.45 4
TKN (mg/L) 45.59 4
Total Phosphorus (mg/L) 3.58 4
Harbour Engineering Joint Venture New Waterford WWTP ERA 12
CHAPTER 3 ENVIRONMENTAL QUALITY OBJECTIVES
Generic Environmental Quality Objectives (EQOs) are generated from established guidelines, typically
the Wastewater Systems Effluent Regulations (WSER), the Canadian Environmental Quality Guidelines
(CEQGs) and other guidelines specified by jurisdiction. Site-specific EQOs are established by adjusting
the generic EQOs based on site-specific factors, particularly ambient water quality. For example, if the
background concentration of a substance is greater than the guideline value (generic EQO), the
background concentration is used as the site-specific EQO. However, substances where the EQO is
based on the WSER are not adjusted based on ambient water quality. Furthermore, there are some
guidelines that are dependent on characteristics of the receiving water like pH or temperature.
EQOs can be determined by three different approaches:
• Physical/ chemical/ pathogenic – describes the substance levels that will protect water quality;
• Whole Effluent Toxicity (WET) – describes the proportion of effluent that can enter the receiving
water without causing toxicological effects (both acute and chronic); and
• Biological criteria (bio-assessment) – describes the level of ecological integrity that must be
maintained.
This assessment follows the physical/ chemical/ pathogenic approach from the Standard Method
outlined in the CCME guidelines. The bio-assessment is not included in the Standard Method as it is still
being developed (CCME, 2008).
3.1 Water Uses
EQOs are numerical values and narrative statements established to protect the receiving water – in this
case the Atlantic Ocean near the Barachois in New Waterford. The first step in determining EQOs is to
define the potential beneficial uses of the receiving water.
The following beneficial water uses have been identified for the Atlantic Ocean in the vicinity of New
Waterford:
• Direct contact recreational activities like swimming and wading at a beach at the end of Browns
Road Extension;
• Secondary contact recreational activities like boating and fishing; and
Harbour Engineering Joint Venture New Waterford WWTP ERA 13
• Ecosystem health for marine aquatic life.
There is no molluscan shellfish harvesting zone in the vicinity of the outfall. The outfall is situated in a
closure zone boundary extending from Point Aconi to Schooner Pond, situated 1125m offshore in the
vicinity of the outfall (shown on Figure 3.1).
Figure 3.1 Location of Existing Outfalls
3.2 Ambient Water Quality
Generic EQOs are first developed based on existing guidelines and then adjusted based on site-
specific factors, particularly background water quality. Water quality data was obtained for two
locations in the Atlantic Ocean along the coast of Cape Breton. The locations were chosen in an
attempt to be representative of ambient water quality outside the influence of the existing
untreated wastewater discharges in CBRM. Samples were collected by HE on May 11, 2018, and the
sample locations are summarized as follows and presented on Figure 3.2. A second set of samples
was collected by HE on November 18, 2018 and analyzed for metals using a different laboratory
method due to elevated detection limits in the first set of samples.
Harbour Engineering Joint Venture New Waterford WWTP ERA 14
BG-1: Near Mira Gut Beach
BG-2: Wadden’s Cove
Figure 3.2 Ambient Water Quality Sample Locations
A third sample was collected north of Port Morien but the results were not considered
representative of background conditions as sample results indicated the sample was impacted by
wastewater. A summary of the ambient water quality data is shown in Tables 3.1 through 3.5.
Harbour Engineering Joint Venture New Waterford WWTP ERA 15
Table 3.1 – Ambient Water Quality Data – General Chemistry
Parameter Units BG1 BG2 AVG
Carbonaceous BOD (CBOD) mg/L <5.0 <5.0 <5.0
COD mg/L 1100 1000 1050
Hardness mg/L 4900 5200 5050
Nitrogen (Ammonia Nitrogen) mg/L <0.050 <0.050 <0.05
TSS mg/L 58 5.0 32
Total Phosphorus (TP) mg/L 0.037 0.032 0.035
Total Kjeldahl Nitrogen (TKN) mg/L 0.19 0.20 0.20
pH pH 7.73 7.68 7.71
unionized ammonia mg/L <0.0007 <0.0007 <0.0007
E. coli MPN/100mL 52 86 69
TRC mg/L NM NM NM
Fluoride mg/L 0.67 0.67 0.67
Nitrate (N) mg/L 0.051 <0.050 0.038
Nitrite (N) mg/L <0.010 <0.010 <0.010
Nitrate + Nitrite mg/L 0.051 <0.050 0.038
Total Cyanide mg/L <0.0010 <0.0010 <0.0010
Note:
NM = Parameter not measured.
Parameters reported as < detection limit have been included in average calculation as half the
detection limit.
Harbour Engineering Joint Venture New Waterford WWTP ERA 16
Table 3.2 – Ambient Water Quality Data – Metals
Parameter Units BG1 BG2 AVG
May-11 Nov-18 May-11 Nov-18
Aluminum mg/L 0.17 0.089 0.083 0.754 0.274
Antimony mg/L <0.010(2) <0.0005 <0.010(2) <0.0005 <0.0005
Arsenic mg/L <0.010 0.00163 <0.010 0.00177 0.0017
Barium mg/L <0.010 0.0074 <0.010 0.0083 0.00785
Beryllium mg/L <0.010(2) <0.001 <0.010(2) <0.001 <0.001
Boron mg/L 3.5 3.42 3.7 3.43 3.51
Cadmium mg/L <0.00010(2)<0.00005 <0.00010(2)<0.00005 <0.00005
Chromium mg/L <0.010(2) <0.0005(1)<0.010(2) 0.00056 0.00041
Cobalt mg/L <0.0040(2) <0.0001(1)<0.0040(2) 0.00031 0.00018
Copper mg/L <0.020(2) <0.0005(1)<0.020(2) 0.00068 0.00047
Iron mg/L <0.50(2) 0.159 <0.50(2) 0.626 0.393
Lead mg/L <0.0050(2) 0.00015 <0.0050(2) 0.0003 0.000225
Manganese mg/L 0.021 0.00747 <0.020(2) 0.0165 0.01499
Molybdenum mg/L <0.020(2) 0.0095 <0.020(2) 0.0086 0.0091
Nickel mg/L <0.020(2) <0.00020 <0.020(2) <0.00020 <0.00020
Selenium mg/L <0.010(2) <0.0005 <0.010(2) <0.0005 <0.0005
Silver mg/L <0.0010(2) <0.00005 <0.0010(2) <0.00005 <0.00005
Strontium mg/L 5.9 7.27 6.3 7.32 6.70
Thallium mg/L <0.0010(2) <0.00010 <0.0010(2) <0.00010 <0.00010
Tin mg/L <0.020(2) <0.001 <0.020(2) <0.001 <0.001
Titanium mg/L <0.020(2) <0.010 <0.020(2) 0.046 0.026
Uranium mg/L 0.0026 0.00248 0.0026 0.00242 0.00253
Vanadium mg/L <0.020(2) <0.01 <0.020(2) <0.01 <0.01
Zinc mg/L <0.050(2) <0.001 <0.050(2) 0.0014 0.00095
Mercury mg/L 0.000013 - 0.000013 - 0.000013
Note:
(1) Value included in average calculation as half the detection limit.
(2) Value omitted from average calculation due to elevated detection limit.
Harbour Engineering Joint Venture New Waterford WWTP ERA 17
Table 3.3 – Ambient Water Quality Data – VOCs
Parameter Units BG1 BG2 AVG
1,2-dichlorobenzene µg/L <0.50 <0.50 <0.50
1,4-dichlorobenzene µg/L <1.0 <1.0 <1.0
Chlorobenzene µg/L <1.0 <1.0 <1.0
1,1,2,2-tetrachloroethane µg/L <0.50 <0.50 <0.50
1,1-Dichloroethylene µg/L <0.50 <0.50 <0.50
1,2-dichloroethane µg/L <1.0 <1.0 <1.0
Benzene µg/L <1.0 <1.0 <1.0
Bromodichloromethane µg/L <1.0 <1.0 <1.0
Bromoform µg/L <1.0 <1.0 <1.0
Carbon Tetrachloride µg/L <0.50 <0.50 <0.50
Chloroform µg/L <1.0 <1.0 <1.0
Dibromochloromethane µg/L <1.0 <1.0 <1.0
Ethylbenzene µg/L <1.0 <1.0 <1.0
Methylene Chloride
(Dichloromethane) µg/L <3.0 <3.0 <3.0
o-xylene µg/L <1.0 <1.0 <1.0
m/p-xylene µg/L <2.0 <2.0 <2.0
Tetrachloroethene
(Tetrachloroethylene) µg/L <1.0 <1.0 <1.0
Toluene µg/L <1.0 <1.0 <1.0
Trichloroethene (Trichloroethylene) µg/L <1.0 <1.0 <1.0
Vinyl Chloride µg/L <0.50 <0.50 <0.50
Harbour Engineering Joint Venture New Waterford WWTP ERA 18
Table 3.4 – Ambient Water Quality Data – PCBs, Phenols, PAHs
Parameter Units BG1 BG2 AVG
Total PCBs µg/L <0.05 <0.05 <0.05
Phenols mg/L 0.011 <0.010 0.0305
1-Methylnaphthalene µg/L <0.050 <0.050 <0.050
2-Methylnaphthalene µg/L <0.050 <0.050 <0.050
Acenaphthene µg/L <0.010 <0.010 <0.010
Acenaphthylene µg/L <0.010 <0.010 <0.010
Anthracene µg/L <0.010 <0.010 <0.010
Benzo(a)anthracene µg/L <0.010 <0.010 <0.010
Benzo(a)pyrene µg/L <0.010 <0.010 <0.010
Benzo(b)fluoranthene µg/L <0.010 <0.010 <0.010
Benzo(g,h,i)perylene µg/L <0.010 <0.010 <0.010
Benzo(k)fluoranthene µg/L <0.010 <0.010 <0.010
Chrysene µg/L <0.010 <0.010 <0.010
Dibenz(a,h)anthracene µg/L <0.010 <0.010 <0.010
Fluoranthene µg/L <0.010 <0.010 <0.010
Fluorene µg/L <0.010 <0.010 <0.010
Indeno(1,2,3-cd)pyrene µg/L <0.010 <0.010 <0.010
Naphthalene µg/L <0.20 <0.20 <0.20
Phenanthrene µg/L <0.010 <0.010 <0.010
Pyrene µg/L <0.010 <0.010 <0.010
Table 3.5 – Ambient Water Quality Data – Organochlorine Pesticides
Parameter Units BG1 BG2 AVG
Aldrin µg/L <0.005 <0.005 <0.005
Dieldrin µg/L <0.005 <0.005 <0.005
a-Chlordane µg/L <0.005 <0.005 <0.005
g-Chlordane µg/L <0.005 <0.005 <0.005
o,p-DDT µg/L <0.005 <0.005 <0.005
p,p-DDT µg/L <0.005 <0.005 <0.005
Lindane µg/L <0.003 <0.003 <0.003
Endosulfan I (alpha) µg/L <0.005 <0.005 <0.005
Endosulfan II (beta) µg/L <0.005 <0.005 <0.005
Endrin µg/L <0.005 <0.005 <0.005
Heptachlor µg/L <0.005 <0.005 <0.005
Heptachlor epoxide µg/L <0.005 <0.005 <0.005
Methoxychlor µg/L <0.01 <0.01 <0.01
alpha-BHC µg/L <0.005 <0.005 <0.005
Mirex µg/L <0.005 <0.005 <0.005
Toxaphene µg/L <0.2 <0.2 <0.2
DDT+ Metabolites µg/L <0.005 <0.005 <0.005
Harbour Engineering Joint Venture New Waterford WWTP ERA 19
3.3 Physical/ Chemical/ Pathogenic Approach
The physical/ chemical/ pathogenic approach is intended to protect the receiving water by ensuring that
water quality guidelines for particular substances are being met. EQOs are established by specifying the
level of a particular substance that will protect water quality. Substance levels that will protect water
quality are taken from the CEQGs associated with the identified beneficial water uses. If more than one
guideline applies, the most stringent is used. Typically the Canadian Water Quality Guidelines (CWQGs)
for the Protection of Aquatic Life are the most stringent and have been used for this assessment. The
Health Canada Guidelines for Canadian Recreational Water have also been used to provide limits for
pathogens (E. coli).
The guidelines for the Protection of Aquatic Life provide recommendations for both freshwater and
marine (including estuarine) environments. Since the receiving water for the proposed New
Waterford WWTP is a marine environment, the marine guidelines were used where available. The
US EPA National Recommended Water Quality Criteria (saltwater) were used when there were no
CCME marine criteria provided. For substances where a marine criterion was not specified by either
CCME or US EPA, the CCME freshwater guidelines were used. There were some parameters that
were detected in the wastewater but for which a criterion did not exist from either CCME or the US
EPA. In those instances, an effort was made to identify an applicable criterion from another
jurisdiction.
Technical Supplement 3 of the Canada-wide Strategy for the Management of Municipal Wastewater
Effluent indicates that for any one substance, if the natural concentration in the upstream location is
higher than the generic EQO equivalent, that concentration will apply as a site-specific EQO, and the
generic EQO must be set aside. Otherwise, site-specific EQOs are not needed. Background water
quality samples were collected from the Atlantic Ocean by HE on May 11, 2018 and the results were
previously summarized in Section 3.2.
Site-specific EQOs were developed for each substance that was detected in the wastewater, for
which there was a generic EQO, and for which the background concentration exceeded the generic
EQO. Site-specific EQOs are discussed in the following sections and included in Table 3.9. EQOs are
derived in the following sections for each substance of potential concern for a medium facility that
was detected in the wastewater.
3.3.1 General Chemistry/ Nutrients
The following general chemistry and nutrients parameters were identified as substances of potential
concern for a medium facility: CBOD, chemical oxygen demand (COD), un-ionized ammonia, total
ammonia, total kjeldahl nitrogen (TKN), total suspended solids (TSS), total phosphorus, pH, total
residual chlorine (TRC), fluoride, nitrate, nitrite, temperature, and total cyanide. EQOs for these
substances are established in the following sections.
Oxygen Demand
Biochemical Oxygen Demand (BOD5) is a measure of the oxygen required to oxidize organic material
and certain inorganic materials over a given period of time (five days). It has two components:
carbonaceous oxygen demand and nitrogenous oxygen demand.
Harbour Engineering Joint Venture New Waterford WWTP ERA 20
Chemical Oxygen Demand (COD) is another measure of oxygen depleting substances present in the
effluent. It is a measure of the oxygen required to chemically oxidize reduced minerals and organic
matter.
Carbonaceous Biochemical Oxygen Demand (CBOD5) measures the amount of biodegradable
carbonaceous material in the effluent that will require oxygen to break down over a given period of
time (five days).
Traditionally performance standards have been set for BOD5; however, the WSER dictate a limit for
CBOD5. This is due to the variable effects of nitrogenous oxygen demand on the BOD5 test.
There are no CWQGs for the protection of aquatic life for CBOD5 in freshwater or in marine waters.
However, because CBOD5 affects the concentration of dissolved oxygen, the CWQG for dissolved
oxygen should be considered. The CWQG for freshwater aquatic life dictates that the dissolved
oxygen concentrations be greater than 9.5 mg/L for early life stages in cold water ecosystems. The
CWQG for marine aquatic life is a minimum of 8 mg/L.
The background dissolved oxygen concentrations were not measured in the receiving water.
However, the concentration of CBOD5 discharged in accordance with the WSER criteria should not
cause the dissolved oxygen (DO) concentration to vary outside of the normal range. Based on an
average annual temperature of 6.9 °C (from Bedford Institute of Oceanography Area 4VN), the
solubility of oxygen in seawater is approximately 9.5 mg/L. Assuming the background concentration
of DO is saturated, there can be a drop of 1.5 mg/L for the DO to be a minimum concentration of 8
mg/L. The average annual temperature was used in this calculation as if the maximum annual
temperature was used, this results in the solubility of oxygen being less than the CWQG for marine
aquatic life. For an ocean discharge, the maximum DO deficit should occur at or near the point
source.
Assuming a deoxygenation rate of 0.33/day based on a depth of approximately 2m at the discharge
location, and assuming a reaeration coefficient of 0.61/day based on a depth of approximately 2m
and an average tidal velocity of 0.16 m/s, the maximum concentration of CBOD that would result in
a drop in DO of 1.5 mg/L can be calculated. The tidal dispersion coefficient has been assumed to be
150 m2/s. The concentration of CBOD potentially affecting DO was calculated to be 40 mg/L.
Therefore, the WSER criteria of 25 mg/L CBOD at discharge should not cause the dissolved oxygen
(DO) concentration to vary outside of the normal range.
Total Ammonia and Un-ionized Ammonia
The CWQG for the protection of aquatic life for total ammonia in freshwater is presented as a table
based on pH and temperature. There is no CWQG for ammonia in marine water. Total ammonia is
comprised of un-ionized ammonia (NH3) and ionized ammonia (NH4+, ammonium). Un-ionized
ammonia is more toxic than ionized ammonia and the toxicity of total ammonia is related to the
concentration of un-ionized ammonia present. The amount of un-ionized ammonia is variable
depending on pH and temperature. The USEPA saltwater guideline for total ammonia is 2.7 mg/L
based on a temperature of 17.7 °C, a pH of 7.7 and a salinity of 30 g/kg. The USEPA guideline of 2.7
Harbour Engineering Joint Venture New Waterford WWTP ERA 21
mg/L will be used as the EQO for total ammonia. As ammonia is a component of total nitrogen (TN),
the actual effluent concentration may be limited by the TN EDO rather than the total ammonia EDO.
However, as the TN EQO is based on concern of eutrophication and not a continuous acceptable
concentration for the protection of aquatic life, both EDOs will be presented separately in the ERA.
The WSER requires that un-ionized ammonia concentrations be less than 1.25 mg/L (as N at 15oC) at
the discharge point. For the purposes of this study, the EQO for un-ionized ammonia was chosen
based on the WSER (1.25 mg/L at discharge).
Total Suspended Solids (TSS)
The WSER specifies a limit of 25 mg/L for TSS at the end of the pipe. The CWQG for the protection of
aquatic life in marine water for total suspended solids (TSS) is as follows:
• During periods of clear flow, a maximum increase of 25 mg/L from background levels for
any short-term exposure (e.g., 24-h period). Maximum average increase of 5 mg/L from
background levels for longer term exposures (e.g., inputs lasting between 24 h and 30 d);
and
• During periods of high flow, a maximum increase of 25 mg/L from background levels at any
time when background levels are between 25 and 250 mg/L. Should not increase more
than 10% of background levels when background is ≥ 250 mg/L.
The background concentration of TSS was an average of 32 mg/L. A maximum average increase of 5
mg/L from background levels would result in an EQO of 37 mg/L. As this is greater than the WSER
criteria, the WSER criteria of 25 mg/L at discharge will apply as the EDO. The background TSS
measurement is higher than would typically be expected in a marine environment, which may be
due to the near shore location of the samples. However, in a worst case scenario where the
background TSS concentration was 0 mg/L, application of the WSER criteria at the end of pipe would
always be the more stringent criteria provided there is greater than five times dilution.
Total Phosphorus and TKN/TN
There are no CWQGs for the protection of aquatic life for phosphorus or nitrogen. However, in both
freshwater and marine environments, adverse secondary effects like eutrophication and oxygen
depletion can occur. Guidance frameworks have been established for freshwater systems and for
marine systems to provide an approach for developing site-specific water quality guidelines. These
approaches are based on determining a baseline condition and evaluating various effects according
to indicator variables. The approach is generally very time and resource intensive, but can be
completed on a more limited scale to establish interim guidelines.
The Canadian Guidance Framework for the Management of Nutrients in Nearshore Marine Systems
Scientific Supporting Document (CCME, 2007) provides a framework as well as case studies for
establishing nutrient criteria for nearshore marine systems. This document provides a Trophic Index
for Marine Systems (TRIX), below in Table 3.6.
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Table 3.6 - Criteria for evaluating trophic status of marine systems (CCME, 2007)
Trophic Status TN
(mg/m3)
TP
(mg/m3) Chlorophyll a (μg/L) Secchi Depth
(m)
Oligotrophic <260 <10 <1 >6
Mesotrophic ≥260-350 ≥10-30 ≥1-3 3-≤6
Eutrophic ≥350-400 ≥30-40 ≥3-5 1.5-≤3
Hypereutrophic >400 >40 >5 <1.5
The background concentrations of TKN and TP were measured as 0.2 mg/L and 0.035 mg/L,
respectively, which corresponds to a eutrophic status based on the phosphorus concentration. The
uppermost limit for this trophic status is a TN concentration of 0.4 mg/L and a TP concentration of
0.04 mg/L.
This document provides another index (NOAA) to determine the degree of eutrophication of the
marine system, below in Table 3.7.
Table 3.7 - Trophic status classification based on nutrient and chlorophyll (CCME, 2007)
Degree of
Eutrophication
Total Dissolved N
(mg/L)
Total Dissolved P
(mg/L)
Chl a
(μg/L)
Low 0 - ≤0.1 0 - ≤0.01 0 - ≤5
Medium >0.1 - ≤1 >0.01 - ≤0.1 >5 - ≤20
High >1 >0.1 >20 - ≤60
Hypereutrophic - - >60
However, the concentrations in Table 3.7 are based on dissolved nitrogen and phosphorus and the
background concentrations are for TKN and total phosphorus. For nitrogen, with a background
concentration of 0.2 mg/L for TKN, an assumption that the dissolved nitrogen background
concentration is anywhere between 50 and 100% of the TKN background concentration would result
in classification as “medium” based on Table 3.7. For phosphorus, with a background concentration
of 0.035 mg/L, an assumption that the dissolved background concentration is anywhere between 29
and 100% of the total background concentration would result in classification as “medium” based on
Table 3.7.
To maintain the same degree of eutrophication, the total dissolved nitrogen and total dissolved
phosphorus in the receiving water should not exceed the upper limit of the “medium” classification
which is 1 mg/L for Total Dissolved Nitrogen and 0.1 mg/L for Total Dissolved Phosphorus. In
order to determine the upper limit of the “medium” eutrophication range based on total
phosphorus and TN concentrations, an assumption must be made as to the percentage of the TN
and phosphorus that exists in the dissolved phase, both in the receiving water and in the effluent.
As a measure of conservatism, an assumption was made that 100% of the TN and phosphorus exist
in a dissolved phase. This allows for the upper limits of the “medium” classification to be used
directly as the EQO which results in an EQO of 1 mg/L for TN and 0.1 mg/L for total phosphorus.
Harbour Engineering Joint Venture New Waterford WWTP ERA 23
The Canadian Guidance Framework for the Management of Nutrients in Nearshore Marine Systems
Scientific Supporting Document (CCME, 2007) presents both of the above criteria for assessing
trophic status and does not provide a recommendation for use of one rather than the other.
However, the framework presents a case study to establish nutrient criteria for the Atlantic
Shoreline of Nova Scotia, and the NOAA index is used. Therefore, that index will be used for the
purpose of this study.
pH
The CWQG for the protection for aquatic life for marine waters is 7.0 to 8.7. This pH range will be
applied as the EQO.
Fluoride
The CCME CWQG for the protection of aquatic life for fluoride is 0.12 mg/L for freshwater. There is
no recommended marine guideline from either CCME or US EPA. The background concentration for
fluoride is 0.67 mg/L. There is a maximum acceptable concentration of 1.5 mg/L specified by the
British Columbia Ministry of Environment (BCMOE). However, as this is a maximum acceptable
concentration and not a long term or continuous concentration, it will not be used. Therefore, the
background concentration of 0.67 mg/L will be applied as the site-specific EQO.
Nitrate
The CCME CWQG for the protection of aquatic life for nitrate is 200 mg/L for marine waters, 45
mg/L as N. Nitrate is substantially less toxic than nitrite and ammonia, but can still yield toxic effects.
Background pH and temperature can influence the conversion of nitrate to nitrite and other forms
of nitrogen. The CCME marine water quality guideline of 45 mg/L will be used as the EQO.
Nitrite
The CCME CWQG for the protection of aquatic life for nitrite is 0.06 mg/L as nitrogen for freshwater,
and there is no recommended marine guideline. Nitrite has been found to be more toxic to some
groups of fish, particularly salmonids. The freshwater guideline of 0.06 mg/L will be applied as the
EQO for this assessment.
Cyanide
The CCME CWQG for the protection of aquatic life for cyanide is 0.005 mg/L (free CN) for
freshwater. There is no CWQG for marine waters. The US EPA water quality criterion for saltwater
is 0.001 mg/L (free CN). Both the CCME and US EPA criteria are for free cyanide, whereas the
Standard Method specifies to sample for total cyanide. Cyanide was not detected in the background
samples (at a detection limit of 0.001 mg/L). The USEPA criteria of 0.001 mg/L will be applied as the
EQO for cyanide. However, comparing sample results from the wastewater characterization
samples to this value will be overly conservative as the analytical results are for total cyanide rather
than free cyanide.
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Total Residual Chlorine
The WSER requires that TRC concentrations be less than 0.02 mg/L. For the purposes of this study,
the EQO of 0.02 mg/L for TRC was chosen based on this regulation. As this is based on the WSER,
0.02 mg/L will apply as the EDO at discharge.
3.3.2 Metals
Of the 25 metals measured during the wastewater characterization study, 13 were detected in the
wastewater of at least one sample. The EQOs for the detected metals are described below.
Aluminum
The CCME CWQG for the protection of aquatic life for aluminum in freshwater is dependent on pH;
the guideline is 5 µg/L if the pH is less than 6.5 and 100 µg/L if the pH is 6.5 or greater. There are no
CWQG or US EPA guidelines for marine waters. The average background concentration of aluminum
was 274 µg/L. The background concentration of 274 µg/L will be used as the site-specific EQO.
Barium
There are no CCME CWQGs for the protection of aquatic life for barium in freshwater or marine
waters. There is also no water quality guideline from the US EPA or British Columbia Ministry of
Environment (BCMOE) for salt water. As no relevant published water quality guidelines were found
for barium, an EQO will not be developed.
Cadmium
The CCME CWQG for the protection of aquatic life for cadmium in marine waters is 0.12 µg/L.
Cadmium was not detected in the background sample (at a detection limit of 0.05 µg/L). Therefore
the EQO will remain the same as the CCME marine WQG of 0.12 µg/L.
Cobalt
There are no CCME CWQGs for the protection of aquatic life for cobalt in freshwater or marine
waters. There is also no US EPA water quality guideline. There are no working guidelines from the
BCMOE for marine waters. As no relevant published water quality guidelines were found for cobalt,
an EQO will not be developed.
Copper
The CCME CWQG for the protection of aquatic life for copper in freshwater is given as an equation
based on water hardness and there is no guideline specified for marine waters. The freshwater
guideline was calculated to be 4 µg/L based on the average background water hardness of 5050
mg/L. The US EPA salt water quality criterion is 3.7 µg/L. The average background concentration of
copper was 0.47 µg/L. Therefore the USEPA salt water quality criterion of 3.7 µg/L will be used as
the EQO.
Harbour Engineering Joint Venture New Waterford WWTP ERA 25
Iron
The CCME CWQG for the protection of aquatic life for iron in freshwater is 300 µg/L. There is no
guideline specified for marine waters. There is no US EPA or BC MOE salt water quality criterion for
iron. The average background concentration for iron was 393 µg/L. The EQO will be based on the
background concentration of 393 µg/L.
Lead
The CCME CWQG for the protection of aquatic life for lead in freshwater is given as an equation
based on water hardness and there is no guideline specified for marine waters. The freshwater
guideline was calculated to be 6 µg/L based on the average background water hardness of 5050
mg/L. The US EPA salt water quality criterion is 8.5 µg/L. The average background concentration of
lead was 0.225 µg/L. Therefore the USEPA salt water quality criterion of 8.5 µg/L will be used as the
EQO.
Manganese
There are no CCME CWQGs for the protection of aquatic life for manganese in freshwater or marine
waters. There is also no criterion provided by US EPA. However, there is a recommended marine
guideline for manganese provided by the British Columbia Ministry of Environment of 100 µg/L. The
background concentration of manganese was 15 µg/L. The guideline of 100 µg/L will be used as the
EQO for manganese.
Nickel
The CCME CWQG for the protection of aquatic life for nickel is 150 µg/L for freshwater based on an
average background hardness of 5050 mg/L. There is no CWQG for marine waters. The US EPA salt
water quality criterion is 8.3 µg/L. Nickel was not detected in the background samples (at a
detection limit of 0.2 µg/L). Therefore the USEPA salt water quality criterion of 8.3 µg/L will be used
as the EQO.
Strontium
There is no CCME CWQG for strontium for the protection of aquatic life. There is no water quality
guideline provided by US EPA or BCMOE. As no relevant published water quality guidelines were
found for strontium, an EQO will not be developed.
Titanium
There is no CCME CWQG for titanium for the protection of aquatic life. There is no water quality
guideline provided by US EPA or BCMOE. As no relevant published water quality guidelines were
found for titanium, an EQO will not be developed.
Uranium
The CCME CWQG for the protection of aquatic life for uranium is 15 µg/L for freshwater and there is
no guideline for marine waters. There is no US EPA water quality guideline for salt water. There is
no BCMOE criteria for marine water. The background concentration for uranium was 2.53 µg/L. The
CCME WQG for freshwater of 15 µg/L will be applied as the EQO.
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Zinc
The CCME CWQG for the protection of aquatic life for zinc is 30 µg/L for freshwater and there is no
guideline for marine waters. The US EPA water quality guideline for salt water is 86 µg/L. The
average background concentration of zinc was 0.95 µg/L. The US EPA criterion of 86 µg/L will be
applied as the EQO for zinc.
3.3.3 E. coli
Pathogens are not included in the CCME WQGs for the protection of aquatic life. The Health Canada
Guidelines for Canadian Recreational Water Quality specify a maximum E. coli concentration of
200 E. coli/100 mL for freshwater for primary contact recreation and 1000 E. coli/100 mL for
secondary contact recreation. The Health Canada guideline for Canadian Recreational Water Quality
for primary and secondary contact recreation in marine water is based on enterococci rather than E.
coli. However, historically Nova Scotia Environment has set discharge limits for E. coli rather than
enterococci for marine discharges. The background concentration of E. coli was 69 E. coli/100 mL.
An EQO of 200 E. coli/ 100mL will apply for primary contact recreation at the beach at the end of
Browns Road Extension. An EQO of 1000 E. coli/ 100mL based on the Canadian Recreational Water
Quality guideline for secondary contact for freshwater will apply elsewhere in the receiving water.
There is currently a molluscan shellfish closure zone in the immediate vicinity of the outfall (SSN-
2006-007 on Figure 3.1). However, consideration will have to be given to E. coli concentrations
outside of the closure zone. It is also possible that the closure zone will be changed once the
proposed WWTPs in CBRM are operational. The Canadian Shellfish Sanitation Program (CSSP)
requires that the median of the samples collected in an area in one survey not exceed 14 E. coli/100
mL, and no more than 10% of the samples can exceed 43 E. coli/100 mL. However, the average
measured background concentration for E. coli was 69 E. coli/100 mL. These background samples
were collected from shore and may not be representative of the actual ambient concentration of E.
coli in the wider area.
3.3.3.1 ORGANOCHLORINE PESTICIDES
Of the list of organochlorine pesticides included in the Standard Method for substances of potential
concern for a medium facility, there were no detections. There was one detection in one sample for
one organochlorine pesticide (endrin aldehyde). As this parameter is not included in the standard
method, an EDO was not developed. This parameter could be considered in the future development
of the compliance monitoring program.
3.3.3.2 POLYCHLORINATED BIPHENYLS (PCBS)
Total polychlorinated biphenyls (PCBs) were not detected in the wastewater and therefore an EQO
was not established.
3.3.3.3 POLYCYCLIC AROMATIC HYDROCARBONS (PAHS)
Polycyclic aromatic hydrocarbons (PAHs) were measured as part of initial wastewater
characterization. Of the 18 substances measured, 7 substances were detected during the
wastewater characterization study: benzo(a)anthracene, benzo(b)fluoranthene, chrysene,
fluoranthene, fluorene, pyrene, and phenanthrene.
Harbour Engineering Joint Venture New Waterford WWTP ERA 27
There are CCME CWQGs for the protection of aquatic life for freshwater for 5 of the 7 substances
that were detected. There were no CCME marine water quality guidelines. There are BC MOE
approved marine water quality guidelines for 2 of the 7 substances. The guidelines are as follows:
• Benzo(a)anthracene – 0.018 µg/L (freshwater);
• Chrysene – 0.1 µg/L (BCMOE marine);
• Fluoranthene – 0.04 µg/L (freshwater);
• Fluorene – 3 µg/L (freshwater); 12 µg/L (BCMOE marine);
• Phenanthrene – 0.4 µg/L (freshwater); and
• Pyrene – 0.025 µg/L (freshwater).
None of the five (6) substances listed above were detected in the background sample (at a detection
limit of 0.01 µg/L). Therefore, the above guidelines will be applied as the EQOs.
3.3.3.4 VOLATILE ORGANIC COMPOUNDS (VOCS)
Of the 21 Volatile organic compounds (VOCs) measured, 2 were detected in the wastewater. There
is a CCME WQG for the protection of aquatic life for freshwater for 1 of the 2 substances that were
detected. There is no marine guideline for either of the substances that were detected. There are
no applicable guidelines for bromodichloromethane. The guideline is as follows:
• Chloroform – 1.8 µg/L (freshwater).
The above guideline will be applied as the EQO.
3.3.3.5 PHENOLIC COMPOUNDS
The CCME WQG for the protection of aquatic life for phenols in freshwater is 4 µg/L. There is no
guideline specified for marine waters. There is no USEPA or BCMOE salt water quality criterion for
phenols. The average background concentration was 30.5 µg/L. The site-specific EQO will be based
on the average background concentration of 30.5 µg/L.
3.3.3.6 SURFACTANTS
Surfactants were not analyzed in the wastewater samples. This analysis was not available locally,
and there are no CWQG available from either CCME or US EPA for non-ionic or anionic surfactants to
compare the results to if the analysis was completed.
3.3.4 Summary
Table 3.8 below gives a summary of the generic and site-specific EQOs determined for parameters of
concern. The source of the EQO has been included in the table as follows:
• WSER – wastewater systems effluent regulations
• Background – Site-specific EQO based on background concentration in receiving water
• CWQG Marine – CCME Canadian Water Quality Guidelines for the Protection of Aquatic Life
Marine
• USEPA Saltwater – United States Environmental Protection Agency National Recommended
Water Quality Criteria – Aquatic Life Criteria – Saltwater Criterion Continuous Concentration
• CGF, Marine – Canadian Guidance Framework for the Management of Nutrients in Nearshore
Marine Systems Scientific Supporting Document
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• BCMOE AWQG – BCMOE Approved Water Quality Guideline
• BCMOE WWQG – BCMOE Working Water Quality Guideline
• CWQG Freshwater – CCME Canadian Water Quality Guidelines for the Protection of Aquatic Life
Freshwater
• HC Primary Contact – Health Canada Guidelines for Canadian Recreational Water Quality –
Primary Contact Recreation
• HC Secondary Contact – Health Canada Guidelines for Canadian Recreational Water Quality –
Primary Contact Recreation
• CSSP - Canadian Shellfish Sanitation Program
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Table 3.8 – EQO Summary
Parameter Generic
EQO Background Selected
EQO Source
CBOD5 (mg/L) 25 <5.0 25 WSER
Total NH3-N (mg/L) 2.7 <0.05 2.7(1) USEPA Saltwater
TSS (mg/L) 25 32 25 WSER
TP (mg/L) 0.1 0.035 0.1 CGF, Marine
TN (mg/L) 1 0.2 1(1) CGF, Marine
pH 7 - 8.7 7.71 7 - 8.7 CWQG Marine
Un-ionized NH3 (mg/L) as N 1.25 <0.0007 1.25 WSER
E. coli – Primary Contact
(MPN/100mL) 200 69 200(2) HC Primary Contact
E. coli – Secondary Contact
(MPN/100mL) 1000 69 1000(2) HC Secondary
Contact
E. coli – Molluscan Shellfish
(MPN/100mL) 14 69 14(2) CSSP
Fluoride (mg/L) 0.67 0.67 0.67 Background
Nitrate (mg/L) 45 0.038 45(1) CWQG Marine
Nitrite (mg/L) 0.06 <0.010 0.06 CWQG Freshwater
Total Cyanide (mg/L) 0.001 <0.0010 0.001 USEPA Saltwater
Aluminum (mg/L) 0.100 0.274 0.274 Background
Cadmium (mg/L) 0.00012 <0.00005 0.00012 CWQG Marine
Copper (mg/L) 0.0037 0.00047 0.0037 USEPA Saltwater
Iron (mg/L) 0.3 0.393 0.393 Background
Lead (mg/L) 0.0085 0.000225 0.0085 USEPA Saltwater
Manganese (mg/L) 0.1 0.015 0.1 BCMOE WWQG
Nickel (mg/L) 0.0083 <0.0002 0.0083 USEPA Saltwater
Uranium (mg/L) 0.015 0.00253 0.015 CWQG Freshwater
Zinc (mg/L) 0.086 0.00095 0.086 USEPA Saltwater
Benzo(a)anthracene (µg/L) 0.018 <0.010 0.018 CWQG Freshwater
Chrysene 0.1 <0.010 0.1 BCMOE AWQG
Fluoranthene (µg/L) 0.04 <0.010 0.04 CWQG Freshwater
Fluorene (µg/L) 12 <0.010 12 BCMOE AWQG
Phenanthrene (µg/L) 0.4 <0.010 0.4 CWQG Freshwater
Pyrene (µg/L) 0.025 <0.010 0.025 CWQG Freshwater
Chloroform (µg/L) 1.8 <1.0 1.8 CWQG Freshwater
Phenols (mg/L) 0.004 0.0305 0.0305 Background
Notes:
Bold indicates EQO is a WSER requirement.
(1) Although the EQOs for ammonia and nitrate have been calculated to be 2.7 mg/L and 45
mg/L, respectively, the EQO of 1 mg/L for total nitrogen would govern. However, as the
EQO for TN is based on eutrophication, EDOs will be developed for all parameters
separately.
(2) EQO is use dependent.
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CHAPTER 4 MIXING ZONE ANALYSIS
4.1 Methodology
4.1.1 Definition of Mixing Zone
A mixing zone is the portion of the receiving water where effluent dilution occurs. In general, the
receiving water as a whole will not be exposed to the immediate effluent concentration at the end-
of-pipe but to the effluent mixed and diluted with the receiving water. Effluent does not
instantaneously mix with the receiving water at the point of discharge. Depending on conditions
like ambient currents, wind speeds, tidal stage, and wave action, mixing can take place over a large
area – up to the point where there is no measureable difference between the receiving water and
the effluent mixed with receiving water.
The mixing process can be characterized into two distinct phases: near-field and far-field. Near-
field mixing occurs at the outfall and is influenced by the configuration of the outfall (e.g. pipe size,
diffusers, etc.). Far-field mixing is influenced by receiving water characteristics like turbulence, wave
action, and stratification of the water column.
Within the mixing zone, EQOs may be exceeded but acutely toxic conditions are not permitted
unless it is determined that un-ionized ammonia is the cause of toxicity. If the un-ionized ammonia
concentration is the cause of toxicity, there may be an exception (under the WSER) if the
concentration of un-ionized ammonia is less than or equal to 0.016 mg/L, expressed as N, at any
point that is 100 m from the discharge point. Outside of the mixing zone, EQOs must be achieved.
The effluent is also required to be non-chronically toxic outside of the mixing zone. The allocation of
a mixing zone varies from one substance to another – degradable substances are allowed to mix in a
portion of the receiving water whereas toxic, persistent, and bio-accumulative substances (such as
chlorinated dioxins and furans, PCBs, mercury, and toxaphene) are not allowed a mixing zone.
A number of general criteria for allocating a mixing zone are recommended in the Strategy, including the
following:
• The dimensions of a mixing zone should be restricted to avoid adverse effects on the designated
uses of the receiving water system (i.e., the mixing zone should be as small as possible);
• Conditions outside of the mixing zone should be sufficient to support all of the designated uses
of the receiving water system;
• A zone of passage for mobile aquatic organisms must be maintained;
Harbour Engineering Joint Venture New Waterford WWTP ERA 31
• Placement of mixing zones must not block migration into tributaries;
• Changes to the nutrient status of the water body as a result of an effluent discharge should be
avoided; eutrophication or toxic blooms of algae are unacceptable impacts;
• Mixing zones for adjacent wastewater discharges should not overlap; and
• Adverse effects on the aesthetic qualities of the receiving water system (e.g. odour, colour,
scum, oil, floating debris) should be avoided (CCME, 2008).
The limits of the mixing zone may be defined for the following three categories of aquatic
environments based on their physical characteristics:
• streams and rivers;
• lakes, reservoirs and enclosed bays; and
• estuarine and marine waters.
Where several limits are in place, the first one to be reached sets the maximum extent of the mixing
zone allowed for the dilution assessment. Nutrients and fecal coliforms are not allocated any
maximum dilution. For fecal coliforms, the location of the water use must be considered and
protected by the limits of the mixing zone.
Based on these general guidelines, mixing zone extents must be defined on a case-by-case basis that
account for local conditions. It may also be based on arbitrary mixing zone limits for open water
discharges, e.g. a 100 m (Environment Canada, 2006) or 250 m (NB Department of Environment,
2012) radius from the outfall and/or a dilution limit. A Draft for Discussion document “Mixing Zone
Assessment and Report Templates” dated July 7, 2016, prepared by a committee of representatives
of the environment departments in Atlantic Canada, provides guidance regarding mixing zones for
ERAs in the Atlantic Provinces. This document recommends that for ocean and estuary receiving
waters a maximum dilution limit of 1:1000 be applied for far-field mixing.
Finally, the assessment shall be based on ‘critical conditions’. For example, in the case of a river
discharge (not applicable here), ‘critical conditions’ can be defined as the seven-day average low
river flow for a given return period. For ocean discharges, we propose to use a maximum one-day
average effluent concentration at the edge of the mixing zone. The Standard Method provides the
following guidance on EDO development:
“…reasonable and realistic but yet protective scenarios should be used. The objective is to simulate
the critical conditions of the receiving water, where critical conditions are where the risk that the
effluent will have an effect on the receiving environment is the highest – it does not mean using the
highest effluent flow, the lowest river flow, and the highest background concentration
simultaneously.”
As a plausible worst case condition is used for the receiving water, the WWTP effluent will be
modelled based on an annual average flow, rather than a maximum daily or hourly flow, as applying
a critical high flow condition for the effluent simultaneously with a worst case condition in the
receiving water would result in overly conservative EDOs as this scenario doesn’t provide a
reasonable or realistic representation of actual conditions.
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4.1.2 Site Summary
The WWTF is assumed to discharge through an outfall pipe perpendicular to the shoreline in shallow
water, extended to a depth estimated at -1.0 m below low tide, at the location of the existing NW2
outfall. The low tide and -1.0 m depth contours were estimated based on navigation charts. The
total average effluent discharge is modeled as a continuous point source of 7,800 m3/day.
The major coastal hydrodynamic features of the area are as follows:
• Along-shore currents along the open coastline are in phase with the tide, i.e. the current
speed peaks at high and low tide;
• At the outfall site, breaking waves and associated longshore currents will contribute to
effluent dispersion during storms. For this assessment, we have assumed calm summer
conditions (i.e. no waves), when effluent dilution would be at a minimum.
4.1.3 Far-Field Modeling Approach and Inputs
The local mixing zone is limited by the water depth at the outfall of approximately -1.0 m Chart
Datum and by the presence of the shoreline. Since the outfall is in very shallow water, the buoyant
plume will always reach the surface upon release from the outfall (Fisher et al., 1979). Far-field
mixing will then be determined by ambient currents, which is best simulated with a hydrodynamic
and effluent dispersion model.
We implemented a full hydrodynamic model of the receiving coastal waters using the Danish
Hydraulic Institute’s MIKE21 model. MIKE21 is ideally suited to the study of outfall discharges in
shallow coastal areas where complex tidal and wind-driven currents drive the dispersion process.
The model was developed using navigation charts, tidal elevations, and wind observations for the
area. A similar model had been used by CBCL for CBRM in the past:
• In 2005 for the assessment of the past wastewater contamination problem at Dominion
Beach, which led to the design of the WWTP at Dominion (CBCL, 2005).
• In 2014 for ERAs at the Dominion and Battery Point WWTPs.
The hydrodynamic model was calibrated to the following bottom current meter data:
• 1992 current meters (4 locations) located in 10 m-depth for the study by ASA (ASA, 1994) on
local oceanography and effluent dispersion;
• 2006 current meters (2 locations) off the Donkin peninsula for the CBCL study of mine
effluent dispersion.
Calibration consisted of adjusting the following parameters:
• Bottom friction;
• Model spatial resolution in the area of the current meters.
Harbour Engineering Joint Venture New Waterford WWTP ERA 33
Numerical Model Domain with Locations of Current Meter Observations and Modeled Outfall
Location are shown in Figure 4.1. Inputs and calibrated outputs are shown in Figure 4.2. The
modelled current magnitudes at New Waterford, Glace Bay, and Donkin are in relatively good
agreement with observations, which is satisfactory to assess the overall dilution patterns of effluent
from the outfall. The effect of waves was not included in the model, and therefore the modeled
effluent concentration near the outfall is expected to be conservatively high.
Figure 4.1 Numerical Model Domain with Locations of Current Meter Observations and
Modeled Outfall Location
Harbour Engineering Joint Venture New Waterford WWTP ERA 34
Figure 4.2 Time-series of Hydrodynamic Model Inputs and Calibration Outputs
Harbour Engineering Joint Venture New Waterford WWTP ERA 35
4.1.4 Modeled Effluent Dilution
Snapshots of typical modeled effluent dispersion patterns are shown on Figure 4.3. Statistics on
effluent concentrations were performed over the 1-month model run, and over a running 7-day and
1-day averaging period. Composite images of maximum and average effluent concentrations are
shown on Figure 4.4.
Effluent concentration peaks at any given location are short-lived because the plume is changing
direction every few hours depending on tides and winds. Therefore, a representative dilution
criteria at the mixing zone limit is best calculated using an average value. We propose to use the
one-day average effluent concentration criteria over the one-month modeling simulation that
includes a representative combination of site-specific tides and winds.
The diluted effluent plume reaches the shoreline to the west and the east of the outfall. It was
found that the plume tended to be streamlined, with turbulence only occurring when the currents
changed direction. Maximum concentrations 100 m away from the outfall are observed both North-
West and South-East of the outfall. The 100 m distance from the outfall to the shoreline is within
the brackets of mixing zone radiuses defined by various guidelines. We propose that this distance
be used as mixing zone limit.
The maximum 1-day average effluent concentration 100 m away from the outfall over the
simulation period is 1.63%. Therefore we propose that a dilution factor of 61.35:1 be used for
calculating EDOs.
Table 4.1 Modelled Dilution Values 100 and 200 m away from the Outfall
Distance
away from
the outfall
Hourly maximum
effluent
concentration
Maximum 1-day
average effluent
concentration
Maximum 7-day
average effluent
concentration
1-Month average
effluent
concentration
100 m 16.43 % (6.09:1
Dilution)
1.63 % (61.35:1
Dilution)
1.14 % (87.72:1
Dilution)
0.85 % (117.65:1
Dilution)
200 m 9.40 % (10.64:1
Dilution)
1.08 % (92.52:1
Dilution)
0.89 % (112.36:1
Dilution)
0.63 % (158.73:1
Dilution)
Harbour Engineering Joint Venture New Waterford WWTP ERA 36
Figure 4.3 Snapshots of Typical Modeled Effluent Dispersion Patterns
Harbour Engineering Joint Venture New Waterford WWTP ERA 37
Figure 4.4 Composite Images of Modeled Maximum 1-Day Average (top) and Maximum 7-
Day Average Effluent Concentrations (middle) with Concentration Time-Series (bottom)
Note: 100-m radius (black) and 200-m radius (grey) circle shown around outfall
Harbour Engineering Joint Venture New Waterford WWTP ERA 38
CHAPTER 5 EFFLUENT DISCHARGE OBJECTIVES
5.1 The Need for EDOs
Effluent Discharge Objectives (EDOs) represent the effluent substance concentrations that will protect
the receiving environment and its designated water uses. They describe the effluent quality necessary
to allow the EQOs to be met at the edge of the mixing zone. The EQOs are established in Chapter 3; see
Table 3.8 for summary of results.
EDOs should be calculated where reasonable potential of exceeding the EQOs at the edge of the mixing
zone has been determined. Typically, substances with reasonable potential of exceeding the EQOs have
been selected according to the simplified approach: If a sample result measured in the effluent exceeds
the EQO, an EDO is determined. As only one sample event was collected from each outfall, rather than
a full year of effluent characterization, EDOs will be developed for all substances of potential concern
that were detected in at least one sample, and for which an EQO was identified.
5.2 Physical/ Chemical/ Pathogenic EDOs
For this assessment, EDOs were calculated using the dilution values obtained at the proposed
average design flow of 7,800 m3/day. This resulted in a dilution of 61.35:1 at the edge of a 100 m
mixing zone. The model shows a dilution of 2000:1 at the beach at the end of Brown’s Road
Extension.
Parameters for which there is a WSER criteria were not allowed any dilution and therefore the EDO
equals the WSER Criteria. The Standard Method does not allocate any maximum dilution for
nutrients and fecal coliforms. For nutrients, it recommends a case-by-case analysis. For fecal
coliforms, the location of the water use must be protected by the limits of the mixing zone.
The dilution values were used to obtain an EDO by back-calculating from the EQOs. When the
background concentration of a substance was less than the detection limit, the background
concentration was not included in the calculation of the EDO.
5.3 Effluent Discharge Objectives
Substances of concern for which an EDO was developed are listed in Table 5.1 below with the
associated EQO, maximum measured wastewater concentration, and the associated EDO.
Harbour Engineering Joint Venture New Waterford WWTP ERA 39
Table 5.1 – Effluent Discharge Objectives at Current Average Daily Flow
Parameter Maximum
Conc. (4) Background Selected
EQO Source Dilution
Factor EDO(1)
CBOD5 (mg/L) 140 <5.0 25 WSER - 25
Total NH3-N (mg/L) 3.1 <0.05 2.7 USEPA Saltwater 61.35 166
TSS (mg/L) 110 32 25 WSER - 25
TP (mg/L) 1.6 0.035 0.1 CGF, Marine 61.35 4.0
TN (mg/L) 10 0.2 1 CGF, Marine 61.35 49.3
Un-ionized NH3 (mg/L) 0.0032 <0.0007 1.25 WSER - 1.25
E. coli -
Primary(MPN/100mL)(2) 1000000 69 200 HC Primary
Contact 2000 262,069
E. coli -
Secondary(MPN/100mL) 1000000 69 1000 HC Secondary
Contact 61.35 57,186
E. coli - Moll.
Shellfish(MPN/100mL) 1000000 69 14 CSSP Note (3) See
Discussion
Fluoride (mg/L) 0.17 0.67 0.67 Background 61.35 0.67
Nitrate (mg/L) 0.32 0.038 45 CWQG Marine 61.35 2758
Nitrite (mg/L) 0.3 <0.010 0.06 CWQG
Freshwater 61.35 3.7
Total Cyanide (mg/L) 0.0035 <0.0010 0.001 USEPA Saltwater 61.35 0.0614
Aluminum (mg/L) 0.6 0.274 0.274 Background 61.35 0.274
Cadmium (mg/L) 0.00032 <0.00005 0.00012 CWQG Marine 61.35 0.00736
Copper (mg/L) 0.014 0.00047 0.0037 USEPA Saltwater 61.35 0.1986
Iron (mg/L) 0.73 0.393 0.393 Background 61.35 0.393
Lead (mg/L) 0.0012 0.000225 0.0085 USEPA Saltwater 61.35 0.508
Manganese (mg/L) 1.1 0.015 0.1 BCMOE WWQG 61.35 5.23
Nickel (mg/L) 0.011 <0.0002 0.0083 USEPA Saltwater 61.35 0.509
Uranium (mg/L) 0.00014 0.00253 0.015 CWQG
Freshwater 61.35 0.768
Zinc (mg/L) 0.079 0.00095 0.086 USEPA Saltwater 61.35 5.22
Benzo(a)anthracene
(µg/L) 0.01 <0.010 0.018 CWQG
Freshwater 61.35 1.10
Chrysene (µg/L) 0.01 <0.010 0.1 BCMOE AWQG 61.35 6.14
Fluoranthene (µg/L) 0.028 <0.010 0.04 CWQG
Freshwater 61.35 2.45
Fluorene (µg/L) 0.011 <0.010 3 BCMOE AWQG 61.35 184
Phenanthrene (µg/L) 0.026 <0.010 0.4 CWQG
Freshwater 61.35 25
Pyrene (µg/L) 0.021 <0.010 0.025 CWQG
Freshwater 61.35 1.53
Chloroform (µg/L) 2.3 <1.0 1.8 CWQG
Freshwater 61.35 110
Phenols (mg/L) 0.0094 0.0305 0.0305 Background 61.35 1.87
Harbour Engineering Joint Venture New Waterford WWTP ERA 40
Notes:
(1) For parameters where the EQO is based on the WSER, and for bio accumulative substances
no dilution is permitted. If toxicity was identified, additional work would be required to define
EDOs.
(2) Dilution at Browns Road Extension Beach of 0.05%.
(3) Existing closure zone boundary is outside the limits of the plume.
(4) Maximum concentration of existing wastewater samples
Yellow highlight indicates the maximum measured concentration exceeds the EQO; orange
highlight indicates the maximum measured concentration exceeds the EDO
Based on the EDOs calculated above, sample results for the following parameters exceeded the EDO
in at least one wastewater characterization sample:
• CBOD;
• TSS;
• E. coli;
• Aluminum; and
• Iron.
Some of these parameters will be reduced through treatment. In addition, the above list is based on
a single sample exceedance at any one of the outfall locations, which may not reflect the results
obtained when both of the individual outfalls are intercepted and combined. Further, some of the
EQOs were based on published water quality guidelines that may be overly stringent for a marine
receiving environment, due to a lack of a more appropriate guideline. Comments on each
parameter in the list above is provided below:
CBOD and TSS
These parameters will meet the EDOs at the discharge of the new WWTP through treatment.
E. Coli
This parameter will meet the EDO for primary and secondary contact recreation through treatment.
In terms of an EDO for E. coli for the protection of molluscan shellfish, an EDO could not be
calculated because the measured background concentration was greater than the EQO. The
average measured background concentration for E. coli was 69 E. coli/100mL compared to an EQO
of 14 E. coli/100mL. These background samples were collected from shore and may not be
representative of the actual ambient concentration of E. coli in the area.
Aluminum
The EDO for aluminum was equal to the background concentration of 0.274 mg/L as the background
concentration was greater than the generic EQO of 0.1 mg/L. However, this EQO is likely overly
conservative as it is based on the CCME CWQG for the protection of aquatic life for freshwater.
There is no CCME CWQG for marine waters. There is no US EPA or BC MOE salt water quality
criterion for aluminum. Therefore, the CCME freshwater guideline was utilized in the absence of a
more appropriate guideline. However, use of the background value for the EDO results in no
dilution being available. In addition, some aluminum removal will likely occur during treatment.
Harbour Engineering Joint Venture New Waterford WWTP ERA 41
Iron
The EDO for iron was equal to the background concentration of 0.393 mg/L as the background value
was greater than the generic EQO of 0.3 mg/L. However, this EQO is likely overly conservative as it
is based on the CCME CWQG for the protection of aquatic life for freshwater. There is no CCME
CWQG for marine waters. There is no US EPA or BC MOE salt water quality criterion for iron.
Therefore, the CCME freshwater guideline was utilized in the absence of a more appropriate
guideline. However, use of the background value for the EDO results in no dilution being available.
In addition, some iron removal will likely occur during treatment.
Harbour Engineering Joint Venture New Waterford WWTP ERA 42
CHAPTER 6 COMPLIANCE MONITORING
The Standard Method utilizes the results of the ERA to recommend parameters for compliance
monitoring according to the following protocol:
• The WSER requirements for TSS, CBOD and unionized ammonia must be monitored to
ensure they are continuously being achieved. Minimum monitoring frequencies are
specified in the guidelines based on the size of the facility. Monitoring of these
substances cannot be reduced or eliminated;
• Nutrients, such as phosphorus and ammonia, and pathogens for which an EDO was
developed should be included in the monitoring program with the same sampling
frequency as TSS and CBOD5;
• For additional substances, the guidelines require that all substances with average effluent
values over 80% of the EDO be monitored;
• If monitoring results for the additional substances are consistently below 80% of the EDO,
the monitoring frequency can be reduced;
• If average monitoring results subsequently exceed 80% of the EDO, monitoring frequency
must return to the initial monitoring frequency; and
• If monitoring results are below 80% of the EDO for at least 20 consecutive samples spread
over a period of at least one-year, monitoring for that substance can be eliminated.
Although the Standard Method results in recommending parameters for compliance monitoring, the
provincial regulator ultimately stipulates the compliance monitoring requirements as part of the
Approvals to Operate. In New Brunswick, the New Brunswick Department of Environment and Local
Government has been using the results of the ERA to update the compliance monitoring program
listed in the Approval to operate when the existing Approvals expire. At this time, it is premature to
use the results of this ERA to provide recommendations on parameters to monitor for compliance,
as the purpose of this ERA was to provide design criteria for design of a new WWTP.
Harbour Engineering Joint Venture New Waterford WWTP ERA 43
CHAPTER 7 REFERENCES
ASA Consulting Limited (1994). “Industrial Cape Breton Receiving Water Study, Phase II”. Prepared
for The Town of Glace Bay.
BC Ministry of Environment (2006). A Compendium of Working Water Quality Guidelines for
British Columbia. Retrieved from: http://www.env.gov.bc.ca/wat/wq/BCguidelines/working.html
CBCL Limited (2005). Dominion Beach Sewer Study. Prepared for CBRM.
CCME (2008). Technical Supplement 3. Canada-wide Strategy for the Management of Municipal
Wastewater Effluent. Standard Method and Contracting Provisions for the Environmental Risk
Assessment.
CCME (2007). Canadian Guidance Framework for the Management of Nutrients in Nearshore
Marine Systems Scientific Supporting Document.
CCME Canadian Environmental Quality Guidelines Summary Table. Water Quality Guidelines for the
Protection of Aquatic Life.
Environment Canada (Environment Canada). 1999. Canadian Environmental Protection Act Priority
Substances List II – Supporting document for Ammonia in the Aquatic Environment. DRAFT –August
31, 1999.
Environment Canada, 2006 - Atlantic Canada Wastewater Guidelines Manual for Collection,
Treatment, and Disposal
Fisheries Act. Wastewater Systems Effluent Regulations. SOR/2012-139.
Fisher et al. (1979). Mixing in Inland and Coastal Waters. Academic Press, London.
Health Canada (2012). Guidelines for Canadian Recreational Water Quality. Retrieved from:
http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/guide_water-2012-guide_eau/index-eng.php
NB Department of Environment & Local Government, 2012 Memo.
Thomann, Robert V. and Mueller, John A. 1987. Principles of Surface Water Quality Modeling and
Control.
Harbour Engineering Joint Venture New Waterford WWTP ERA 44
USEPA. National Recommended Water Quality Criteria for Saltwater. Retrieved from:
http://water.epa.gov/scitech/swguidance/standards/criteria/current/index.cfm
Prepared by: Reviewed by:
Holly Sampson, M.A.Sc., P.Eng. Karen March, M.Sc.
Intermediate Chemical Engineer Environmental Scientist
Harbour Engineering Joint Venture Appendices
APPENDIX A
Laboratory Certificates
HEJV New Waterford Wastewater System Pre‐Design Summary Report Appendices
APPENDIX D
New Waterford Wastewater Treatment
Facility Site Desktop Geotechnical Review
301 Alexandra Street, Sydney, NS B1S 2E8
t: 902.562.2394 f: 902.564.5660 www.exp.com
301 Alexandra Street, Sydney, NS B1S 2E8
t: 902.562.2394 f: 902.564.5660 www.exp.com
October 26, 2018 SYD-00245234-A0/60.2
Mr. Terry Boutilier
Dillon Consulting Limited
275 Charlotte Street
Sydney, NS B1P 1C6
Re: Wastewater Treatment Plant Geotechnical Desktop Study
New Waterford Sit
Dear Mr. Boutilier:
It is the pleasure of EXP Services Inc. (EXP) to provide Dillon Consulting Limited (Dillon) with this letter
report summarizing the preliminary review completed by EXP on the potential site for the construction
of a wastewater treatment facility in New Waterford, Nova Scotia.
Background
A geotechnical desktop study is an essential tool used by engineers to identify and gather as much
information as possible pertaining to the probable ground conditions at a proposed construction site
without commissioning an intrusive ground investigation. The information obtained from the desktop
study will identify potential problems, hazards and/or constraints associated with the probable ground
conditions in the proposed area of construction, as well as provide geotechnical recommendations for
new construction activities. When a walkover survey is completed in conjunction with the desktop
study it will allow engineers to refine and enhance their understanding of each of the sites in relation
to the topography, earth exposures, drainage conditions, etc. When completed together (the desktop
study and the walkover survey), the findings will provide invaluable information in the early stages of
the design at a negligible cost. It is the intent of the desktop study and walkover survey not only to look
at the site, but also at its surroundings. Noted below are the key findings to be reported in any desktop
study and walkover assessment:
• site topography;
• geology (surficial ground cover, probable overburden soil and bedrock type);
• geotechnical problems and parameters;
• previous land use (aerial photographs);
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• underground/surface mining activities; and
• proposed supplemental ground investigation methods (test pits and/or boreholes).
Subject Site Description and Topography
The proposed site for the new wastewater treatment plant (WWTP) is located on a vacant lot on the
northern coastline of the Barrachois, off of Mohan Street in New Waterford, Nova Scotia, and is
identified by Property Identification Number (PID) 15483100. The site has an undulating topography
associated with Irish Brook, which bisects the property. Along the Atlantic coastline the property drops
off rapidly (at the cliff face). The proposed construction property is bound by the Atlantic coastline
along the northern perimeter of the site, Irish Brook to the south and southeastern perimeters and
Mohan Street to the western perimeter. Figure 1 depicted below outlines the proposed location of the
site.
Figure 1: Proposed location of the new WWTP in New Waterford.
Published Geological Mapping (Surficial and Bedrock)
Review of the surficial geological mapping of the study area indicated that the subsurface geology
consists of a Stony Till Plain. This type of till is generally comprised of a stony, sandy matrix material
with varying amounts of cobbles and boulders and can vary in thickness from 2 to 20 metres thick.
Typically, these materials were released from the base of ice sheets during the melting process of the
ice sheet.
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A review of the existing bedrock mapping for the area indicates that the site is underlain by materials
from the late carboniferous period, which are identified in this area as material from the Sydney Mines
Formations of the Morien Group. These formations are comprised of fluvial and lacustrine mudstone,
shale, siltstone, limestone and coal.
A review of historical mapping and online reference documents indicated that mining activities have
been carried out extensively in an area west and southwest of the proposed construction site (but not
directly under the site). The workings were the standard room and pillar coal extraction process. It
should be noted that pillars may have been mined at some point. Mapping indicated that the Hub
(Barrasois) Seam outcroppings traverse the proposed property. However, it is approximately 100 to
150 metres south of the footprint of the proposed construction site. Two abandoned mine openings
(AMOs) were found on the site. The AMOs have identification numbers MWA-1-159 and MWA-1-449.
Review of the report suggests that both openings were backfilled to grade as a protective measure.
Existing Ground Conditions
At the time of the investigation, the site was primarily covered with low lying vegetation. All-terrain
vehicle (ATV) trails were observed crisscrossing over the site, exposing the underlying glacial till soils.
The overburden soil (glacial till) exposure was observed along the cliffside. The thickness of the
overburden appears to be in the range of 1.2 to 2.0 metres thick (thicker accumulations are expected
deeper inland). The glacial till was visually described as being a poorly graded silty SAND with gravel
and varying amounts of cobbles (flat and subangular in shape). The till mixture is in a compact state of
relative density. The till should provide satisfactory bearing stratum for the support of shallow
foundations with bearing capacities between 150 and 200 kPa. The underlying bedrock would provide
a higher capacity for allowable bearing.
The bedrock underlying the till was also observed along the cliffside. The exposed bedrock consisted of
alternating layers of shale, mudstone, sandstone and/or siltstone. The formations are consistent with
the material identified in the regional mapping. The exposed bedrock along the Atlantic coastline is
showing evidence of erosion.
Geotechnical Problems and Parameters
Summarized below are the key geotechnical problems of the site.
• There is evidence of the erodibility of subsurface soils and bedrock exposure along the Atlantic
coastline. A Coastal Protection Plan will be required for this site.
• The area west and southwest of the proposed construction site was undermined due to
historical coal mining activities and there is a potential for undocumented bootleg pits/mines
in the area.
• There is the potential for a layer of limestone to be present underlying the surficial ground and
alternating layers of bedrock below the site. Limestone is water soluble and has the potential
to develop karsts voids (sinkholes).
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Previous Land Use
Aerial photographs from 1931 to 2018 have been reviewed and are summarized below.
• An aerial photograph taken in 1931 depicts the site void of any structures. It was primarily
covered with low lying vegetation. A footpath traverses the site along the northern side of Irish
Brook. Residential dwellings were observed to the east, west and south of the site.
• An aerial photograph taken in 1947 depicts a new structure near the southwest corner of the
site. Some costal erosion along the Atlantic coast line was observed. Continued development
of residential housing surrounding the site.
• An aerial photograph taken in 1954 depicts little to no discernable change to the site since the
1947 photograph was taken.
• An aerial photograph taken in 1963 depicts little to no discernable change to the site since the
1954 photograph was taken.
• An aerial photograph taken in 1973 depicts a new wharf has been constructed on the southern
side of Irish Brook. Additional coastal erosion was visible.
• An aerial photograph taken in 1987 depicts little change to the site since the 1973 photograph
was taken.
• An aerial photograph taken in 1993 depicts little to no discernable change to the site since the
1987 photograph was taken. Additional coastal erosion was visible.
• An aerial photograph taken in 2010 depicts an area of vegetation stripped from the
southwestern corner of the site.
• An aerial photograph taken in 2018 shows an increase in vegetation on the site.
Proposed Supplemental Ground Investigation Methods
It is also recommended that a preliminary geotechnical investigation (land based drilling) be completed
at the site to verify the presence or absence of authorized and/or bootleg mining activities undertaken
in the area, as well as the potential of future subsidence that could impact structures constructed on
the site.
Ultimately, the goal of the supplemental geotechnical ground investigation is to collect pertinent
information pertaining to the subsurface conditions within the footprint of the proposed new facility.
This information will then be used to develop geotechnical recommendations for use in the design and
construction of the new facility.
Borehole locations should be selected based upon the location of buried infrastructure (sewer, water,
electrical and fiber optic lines) and to provide adequate coverage of the site. It is proposed that
representative soil samples be collected continually throughout the overburden material of each of the
four boreholes advanced at the site. Additionally, it is recommended that during the investigation
samples of the bedrock should be collected continuously to a depth of at least 30 metres or more, in
two of the four boreholes. The intent of the bedrock coring is to:
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• verify the presence or absence of underground mine workings (both authorized commercial
activities and/or bootleg pits).
• increase the odds of advancing the borehole through the roof of any mine working (to
determine the potential void space) and not into a supporting pillar (if applicable).
• accurately characterize the bedrock for design of either driven or drilled piles, if needed.
It is recommended that the remaining two boreholes be terminated either at 12 metres depth below
ground surface or once refusal on assumed bedrock is encountered (whichever comes first). It should
be noted that if pillar extraction took place, fractures will likely extend 20 metres above mine workings.
If this is the case, drill return water may be lost and rock wedges may be encountered. This will inhibit
coring and an alternative method of drilling through fractured rock may have to be pursed.
A Geotechnical Engineer should oversee the advancement of each of the boreholes. A CME 55 track
mounted geotechnical drill rig (or equivalent), equipped with bedrock coring equipment and a two-
man crew (driller and helper), should be used to advance each of the boreholes. Representative soil
samples should be attained from a 50 mm diameter standard split spoon sampler during Standard
Penetrating Tests (SPT) conducted ahead of the casing and/or auger equipment. A preliminary
assessment of each recovered sample should be completed for particle size, density, moisture content
and color. The SPT should continue until refusal or contact with assumed bedrock. Bedrock should be
confirmed through coring of the material using coring equipment and drill casing. Each core sample
should be removed from the core barrel and placed into core boxes for identification.
Upon completion of the intrusive portion of the program, all boreholes are to be plugged (at various
depths within the borehole) using a bentonite plug and backfilled to grade using silica sand. It should
be noted that continuous grouting (with neat cement and/or bentonite) may be required to backfill the
boreholes to grade. The continuous grouting will protect water supplies from contamination sources;
it can prevent the movement of water between aquifers; and prevent and stabilize the water soluble
bedrock that may be present on the site. Following the installation and backfilling activities, the location
and elevations are to be determined using Real Time Kinematic (RTK) survey equipment in the AST 77
coordinate system.
This letter report is prepared for the New Waterford site. Should you have any questions or concerns,
please contact John Buffett or Gary Landry at 902.562.2394.
Sincerely, Sincerely,
John Buffett, P.Eng., B.Sc., RSO Gary Landry, P.Eng., B.Sc.
Project Engineer Project Manager
EXP Services Inc.
HEJV New Waterford Wastewater System Pre‐Design Summary Report Appendices
APPENDIX E
New Waterford Wastewater System
Archaeological Resources Impact
Assessment