Annual Report 2019
WASTEWATER TREATMENT
Wastewater Treatment | ANNUAL REPORT 2019 1
Table of Contents
Introduction ......................................................................................................3
Wastewater Treatment Process ......................................................................4
Wastewater Treatment Process Summary ......................................................6
Biosolids Summary ..........................................................................................8
Plant Treatment Process Schematic ...............................................................9
Infrastructure Projects ..................................................................................10
Compliance & Quality Control Laboratory ....................................................12
Calibration & Maintenance of Monitoring Equipment ..................................13
Sewer Use Control Program ..........................................................................13
Complaints .....................................................................................................14
By-Pass Events ..............................................................................................14
Data Tables.....................................................................................................15
Staff Organization ..........................................................................................17
Infrastructure and Operations ...................................................................17
Environment Division .................................................................................17
Water Pollution Control Plant ...................................................................17
List of Figures
Figure 1: Monthly Effluent Results - TSS and CBOD5 ......................................6
Figure 2: Monthly Effluent Results - Total Phosphorus ...................................7
Figure 3: Monthly Effluent Results - pH ...........................................................7
Figure 4: Monthly Effluent Results - Ammonia Nitrogen ................................8
Figure 5: Biosolids Shipped to Solid Waste & Recycling Facility .....................8
List of Data Tables
Table 1: Flows Received ..................................................................................15
Table 2: Plant Effluent Quality – Monthly Average Concentration .................15
Table 3: Plant Effluent Quality – Monthly Average Loading ...........................16
Table 4: Sludge Dewatering Results ..............................................................16
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Wastewater Treatment | ANNUAL REPORT 2019 3
Introduction
The City of Thunder Bay (City) owns and operates the Water Pollution Control Plant (WPCP) located at 901 Atlantic Avenue. The Plant provides primary and secondary treatment, phosphorus and ammonia removal and anaerobic sludge digestion for the entire serviced area of Thunder Bay. Disinfection of the effluent occurs on a seasonal basis, from April 15 to October 15. The treatment facility has a rated capacity of 84.5 million litres per day.
This report is prepared on an annual basis to meet the requirements of the Ontario Ministry of the Environment, Conservation and Parks (MECP) amended Environmental Compliance Approval (ECA) #6927-9QDM2P for the design and operation of the Atlantic Avenue WPCP. It also serves to explain the operation of a vital part of the City of Thunder Bay’s infrastructure.
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Wastewater Treatment Process
1. INFLUENT PUMP STATION
Wastewater from the serviced area in Thunder Bay enters the Water Pollution Control Plant at the Influent Pump Station (IPS) where five pumps are available to deliver the wastewater to the preliminary treatment process. The wastewater then flows by gravity to the end of the primary treatment process.
2. PRELIMINARY TREATMENT
The Preliminary Treatment Process removes large objects such as rags, paper, and wood debris. The wastewater enters two aerated grit tanks, where the flow is slowed to allow solids to settle out. Suspended, heavier material such as sand and gravel settles to the bottom of the grit tanks, where it is collected and dewatered by grit classifiers. This material is collected and hauled to the City’s Solid Waste and Recycling Facility (SWRF). Polymer is added to the grit tanks to increase the settlement of suspended solids. Aluminum sulphate is also added to help remove phosphorus and suspended solids.
3. PRIMARY TREATMENT
The Primary Treatment settles the organic material and dissolved contaminants by gravity in four large rectangular settling tanks (clarifiers). The wastewater flows very slowly through the clarifiers, where the wastewater, now called primary effluent, overflows the outlet weirs. A surface skimmer pushes fats, oils and greases (FOG), to the scum troughs, which then feeds the FOG into the scum treatment system. Settled sludge is moved by a skimmer along the bottom to a sludge hopper where the sludge is collected and then treated in the anaerobic digesters to allow decomposition by micro-organisms.
4. SECONDARY TREATMENT
Secondary treatment is a biological process that uses aerobic bacteria to consume suspended solids and dissolved organic materials in wastewater. The WPCP uses the Biological Aerated Filter (BAF) process. The BAF process removes biochemical oxygen demand, suspended solids and ammonia. In the filters, the primary effluent flows upward through a bed of media. The filters are aerated to satisfy the requirements of the micro-organism population and maintains biological activity and growth.
Sludge generated in the secondary treatment process is thickened in the Dissolved Air Flotation (DAF) plant before being treated in the anaerobic digesters.
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5. DISINFECTION
Treated wastewater is disinfected with ultraviolet (UV) light to destroy pathogenic bacteria. The process utilizes UV light, and therefore has no impact on the chemical composition of the water. UV disinfection is required from April 15th to October 15th.
6. DISCHARGE
The final step in the wastewater treatment process is the return of clear treated water to Lake Superior. The effluent from the WPCP is discharged into the Kaministiquia River, roughly 400 meters upstream of Lake Superior.
7. SOLIDS TREATMENT AND COGENERATION
Sludge is produced as a by-product of the wastewater treatment process. Two types of sludge, primary and secondary, are processed in the anaerobic digesters.
Biogas contains approximately 60% methane (the combustible component of natural gas). The cogeneration system converts the biogas to electricity and captures the heat generated from the engine. The biogas can also be used in the plant boilers to generate heat.
Digested sludge is mechanically dewatered using centrifuges to separate the solids from the liquid to create a sludge cake. The centrifuges increase the solids content of the digested sludge from approximately 2% to 25%. The sludge cake is collected in bins and transported to the City’s SWRF for final disposal.
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The TSS effluent concentrations remained below the ECA objective and limits for the entire year. See Figure 1 below for the monthly TSS and CBOD5 results.
WASTEWATER TREATMENT PROCESS SUMMARY
The WPCP must operate within the effluent limits outlined in the Ontario Ministry of Environment, Conservation and Parks Environmental Compliance Approval. The ECA lists effluent limits for the following parameters: Total Suspended Solids (TSS), Carbonaceous Biochemical Oxygen Demand (CBOD5), Total Phosphorus (TP), pH and E.Coli. In addition to the effluent limits, there are effluent objectives which are lower concentrations than the limits. The WPCP strives to produce effluent quality to meet these objectives. Total Ammonia Nitrogen (TAN) is currently listed only as an effluent objective. There are two objectives for ammonia, one for the freezing period (November 1 to March 31) and one for the non-freezing period (April 1 to October 31). E. Coli has a seasonal limit and objective from April 15 to October 15. The following summarizes the performance and success of the plant relative to these limits and objectives.
Januar
y
Februar
y
March
April
MayJu
neJu
ly
August
September
October
Novem
ber
Decem
ber
25
20
15
10
5
0
Effluent CBOD5 ECA ObjectiveECA LimitEffluent TSS
Con
cent
ratio
n (m
g/L)
Figure 1: Monthly Effluent Results - TSS and CBOD5
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The effluent total phosphorus monthly concentrations in 2019 were below the ECA limit for the entire year and below the ECA objective for the majority of the year. In February, the total phosphorous concentration in the effluent spiked above the objective. The primary coagulant dosage was increased to bring the total phosphorus concentration below the objective. The total phosphorus concentration in the wastewater entering the WPCP increased in February due to the dry weather and low wastewater flows. Refer to Figure 2 for the monthly effluent total phosphorus concentrations for 2019.
The effluent pH for the WPCP remained within the range outlined in the ECA as shown in Figure 3.
Januar
y
Februar
y
March
April
MayJu
neJu
ly
August
September
October
Novem
ber
Decem
ber
1.2
1
0.8
0.6
0.4
0.2
0
Effluent Phosphorus ECA ObjectiveECA Limit
Con
cent
ratio
n (m
g/L)
11
10
9
8
7
6
5
Effluent pH ECA ObjectivesECA Limits
pH (S
U)
Januar
y
Februar
y
March
April
MayJu
neJu
ly
August
September
October
Novem
ber
Decem
ber
Figure 2: Monthly Effluent Results - Total Phosphorus
Figure 3: Monthly Effluent Results - pH
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Figure 4: Monthly Effluent Results - Ammonia Nitrogen
BIOSOLIDS SUMMARY
The dewatered sludge generated in 2019 is presented in Figure 5. In 2019, 7,843 tonnes of biosolids (dewatered sludge) were hauled to the City’s SWRF by a contracted waste hauler. The biosolids are weighed before being buried with incoming solid non-hazardous waste on a daily basis. Dewatered sludge will continue to be buried at the City’s SWRF in 2020. The WPCP expects to generate approximately 9,000 tonnes of biosolids in 2020, assuming a similar wastewater flow.
The monthly effluent results for total ammonia nitrogen remained below the ECA objectives for the majority of the year. The effluent ammonia concentrations increased during periods of colder temperatures, as expected, due to colder wastewater temperatures and a limited nitrifying capacity in the secondary treatment process. See Figure 4.
Con
cent
ratio
n (m
g/L)
Januar
y
Februar
y
March
April
MayJu
neJu
ly
August
September
October
Novem
ber
Decem
ber
850800750700650600550500450
Tonn
es (T
)
2019 Biosolids Generated
Januar
y
Februar
y
March
April
MayJu
neJu
ly
August
September
October
Novem
ber
Decem
ber
ECA Freezing ObjectiveAmmonia ECA Non Freezing Objective
Figure 5: Biosolids Shipped to Solid Waste & Recycling Facility
76543210
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PLANT TREATMENT PROCESS SCHEMATIC
Secondary TreatmentPrimary Treatment
BAF – Biological Aerated Filter
C – Carbonaceous
N – Nitrification
DAF – Dissolved Air Flotation
Automated Sample Point
Headworks Bypass
PolymerBarScreens #1 to #4
Primary Clarifiers #1 to #4
BAF Fine Screens
Aerated Grit Tanks 1&2
Final Effluentto
KaministiquiaRiver
Ultraviolet Disinfection (Seasonal)
BAF “N”ParshallFlume
BAF “C”
Raw Sludge
To Sludge Blend Tank
Thickened Waste
Secondary Sludge
Main Pump Station Pumps
#1 to #5Screenings to Landfill Backwash
Waste Tank
Alum
DAF
Grit to Landfill
Raw Sewage
BackwashSupply Tank
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Influent Pump Station (IPS)• New HMI screen; • Wet well #2 cleaning.
Primary Treatment• PC-1,2,3,4 service (including
PC-1 expansion joint repair);• Distribution channel cleaning.
Sludge System• Routine cleaning & service
of digester #1;• Blend tank cleaning & inspection;• New raw sludge pumping
flush connection.
Biological Aeration Filtration (BAF)• Replace BAF process inlet
valves (12 filters);• Process air valve controls &
programming (optimization);• New BAF (gallery) HMI screens;• BAF filter service #8, 9, 12;• New control valves (including
programming logic) installed on fine screen #8.
INFRASTRUCTURE PROJECTS
As part of the Environment Division’s Asset Management Plan, many projects were carried out during 2019 to protect and improve the equipment and infrastructure.
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Dissolved Air Flotation (DAF)• DAF polymer system equipment
upgrade and installation.
Heating and Ventilation (H&V)• Sludge dewatering building
H&V system repairs; • IPS H&V control modifications;• BAF & Dissolved Air Flotation Building
control modifications, including occupancy programming.
Buildings & Grounds• Administration building - re-roofing,
exterior caulking, flashing and repairs;• New security camera system installed;• Perimeter fence repairs;• Digester #3 re-roofing;• Network security scan & vulnerability test.
Wastewater Collection - Pollution Prevention Control Plan• Separation of 0.9 km of sanitary
and storm sewers;• Storm sewer separation projects
occurred on Pruden Street, Finlayson Street, Pacific Avenue, Grey Street, Dobie Street and Oakdale Crescent;
• Syndicate Avenue Project involved 0.34 km of sanitary sewer replacement to re-purpose the existing combined sewer as a storm sewer. As a result, the combined sewer overflow (CSO) on Syndicate Avenue at the Neebing River is to be fully decommissioned and abandoned.
Cogeneration• Cogen major service.
Electrical Systems• Infrared scan windows installed.
Disinfection System• UV lamp replacement and major service.
Dewatering• Centrifuge #1 major repair (drive
motor, gear box, controls).
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COMPLIANCE & QUALITY CONTROL LABORATORY
The Compliance & Quality Control (C&QC) laboratory supports the process control testing for the WPCP on a daily basis. Under the direction of the Chief Chemist, two full-time laboratory technicians carry out operational analytical requirements, as outlined in the Environment Compliance Approval (ECA). The testing includes, but is not limited to the following parameters: carbonaceous biochemical oxygen demand (CBOD5), total suspended solids (TSS), total and soluble phosphorous (TP and SP), total solids (TS), volatile solids (VS), volatile acids, ammonia, chemical oxygen demand (COD), capillary suction time (CST), alkalinity and ultraviolet transmittance (UVT). The laboratory has an internal quality assurance program in place for many of these parameters such as ammonia, total suspended solids, phosphorous, pH and CBOD5 experiments. Additionally, the calibration and verification of the analytical equipment used in the laboratory is annually confirmed by the manufacturer to ensure the highest standards are continually met.
An external accredited laboratory also conducts tests for metals, COD, ammonia and total Kjeldahl nitrogen (TKN). Also, the C&QC laboratory provides analytical support for the Solid Waste & Recycling Facility (SWRF) as well as for the Sewer Use Control Program.
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CALIBRATION & MAINTENANCE OF MONITORING EQUIPMENT
Calibration and maintenance of the effluent monitoring equipment and automatic samplers were carried out by the Environmental Inspector and Laboratory Technicians. The influent flow measuring device is verified for accuracy by Plant Electricians on a routine basis and calibrated by a third party on an annual basis.
SEWER USE CONTROL PROGRAM
The Hauled Sewage Monitoring Program recorded a total of 579 loads of processed water and septic/holding tank wastes, which accounted for 8.65 million litres received and processed at the WPCP in 2019.
The Over-Strength Discharge Program, provided through the City’s Sewer Use By-Law, allows participating industrial users to discharge effluent which contains excess phosphorous, CBOD5, and total suspended solids higher than the limits outlined in the By-Law. An additional fee based on these three parameters, and on the actual treatment cost of the loading above the By-Law limits, is then applied to these industries. Industries approved to discharge are issued agreements, as required.
The City’s Environmental Inspector responded to 7 reports of possible spills or pollution complaint calls in 2019. Each of these issues were addressed and remediated as required.
Records are maintained for each report submitted.
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BY-PASS EVENTS
During 2019, there were no combined sewer overflows at the duckbill located in the McVicar Creek.
Throughout 2019, the WPCP experienced a number of secondary and partial secondary by-pass events. Over the course of the year, approximately 469,200 cubic meters of wastewater received primary treatment, but by-passed the secondary treatment plant before entering the Kaministiquia River. High wastewater flows, caused by the spring snow melt and heavy rainfall events, accounted for over 78% of the volume of the by-passes. The other major contributor, at 21% of the by-pass volume, was the loss of utility line power. As required by the WPCP’s ECA, the by-passes were disinfected. All by-pass events were reported to the MECP, Thunder Bay District Health Unit and Environment Climate Change Canada following the established reporting protocol.
COMPLAINTS
The WPCP did not receive any inquiries from the public in 2019.
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DATA TABLES
Table 1: Flows Received
Month Influent Volume
(ML)
Total Precipitation
(mm)
Maximum Daily Flow
(MLD)
Average Daily Flow
(MLD)
January 1,711 30 152 55.2
February 1,553 37 160 55.5
March 2,127 32 182 68.6
April 3,066 64 217 102.2
May 2,910 43 129 93.9
June 2,436 68 144 81.2
July 2,150 83 129 69.4
August 1,970 64 163 63.5
September 2,402 99 150 80.1
October 2,707 92 241 87.3
November 1,778 34 108 59.3
December 1,507 27 126 48.6
Total 26,317 673
Average 2,193 56 72.1
Table 2: Plant Effluent Quality – Monthly Average Concentration
Month CBOD5 (mg/L)
TSS (mg/L)
TP (mg/L)
E Coli (#/100 mL)
TAN (mg/L)
pH (SU)
Temperature (°C)
Limit 25.0 25.0 1.0 200 No Limit 6.0 to 9.5 No Limit
Objective 15.0 15.0 0.5 150Apr 1 to Oct 31: 3.0 Nov 1 to Mar 31: 5.0 6.5 to 8.5 No Objective
January 11.9 11.8 0.5 5.0 6.5 10.9
February 12.6 12.0 0.6 7.0 7.1 10.7
March 9.2 10.8 0.4 3.2 7.1 10.7
April 5.9 8.0 0.2 6 2.4 7.5 9.8
May 4.4 6.6 0.2 31 2.1 7.6 11.4
June 5.6 6.5 0.2 53 1.5 7.7 14.1
July 4.4 6.3 0.2 150 1.5 7.7 17.7
August 4.3 7.7 0.3 130 2.3 7.6 17.5
September 4.9 7.1 0.2 130 1.0 7.8 16.3
October 5.2 7.5 0.3 40 1.0 8.0 14.6
November 5.7 6.5 0.2 1.5 7.7 13.5
December 8.5 9.1 0.4 3.5 7.5 11.8
Average 6.9 8.3 0.3 77 2.7 7.5 13.3
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Table 3: Plant Effluent Quality – Monthly Average Loading
Month CBOD5 (kg/d)
TSS (kg/d)
TP (kg/d)
Limit 2112.5 2112.5 84.5
January 644.8 648.2 27.1
February 677.7 667.5 32.6
March 793.1 748.2 27.4
April 595.5 810.3 20.3
May 411.9 613.7 16.8
June 466.3 544.1 14.9
July 307.0 433.1 13.1
August 283.7 491.6 17.6
September 399.6 576.2 19.4
October 460.0 663.5 22.5
November 343.6 380.2 14.2
December 432.0 435.7 19.5
Average 484.6 584.4 20.5
Table 4: Sludge Dewatering Results
Month Sludge to Dewatering
(m3/day)
Total Sludge Dewatered
(m3)
Biosolids Generated (Tonnes)
January 274 8,485 638
February 263 7,371 523
March 272 7,894 672
April 325 9,741 682
May 324 10,054 789
June 338 10,142 732
July 296 9,171 697
August 246 7,623 525
September 267 8,025 601
October 261 8,077 668
November 269 8,079 673
December 294 9,106 643
Average 286
Total 103,768 7,843
The TSS effluent concentrations remained below the ECA objective and limits for the entire year. See Figure 1 below for the monthly TSS and CBOD5 results.
The effluent total phosphorus monthly concentrations in 2019 were below the ECA limit for the entire year and below the ECA objective for the majority of the year. In March, the total phosphorous concentration in the effluent spiked above the objective. The primary coagulant dosage was increased to bring the total phosphorus concentration below the objective. The total phosphorus concentration in the wastewater entering the WPCP increased in February due to the dry weather and low wastewater flows. Refer to Figure 2 for the monthly effluent total phosphorus concentrations for 2019.
Figure 2: Monthly Effluent Results - Total Phosphorus
The effluent pH for the WPCP remained within the range outlined in the ECA as shown in Figure 3.
Figure 3: Monthly Effluent Results - pH
The monthly effluent results for total ammonia nitrogen remained below the ECA objectives. The effluent ammonia concentrations increased during periods of colder temperatures due to colder than normal wastewater temperatures and a limited nitrifying capacity in the secondary treatment process. See Figure 4.
Figure 4: Monthly Effluent Results - Ammonia Nitrogen
BIOSOLIDS SUMMARY
The dewatered sludge generated in 2019 is presented in Figure 5. In 2012019, 7,843 tonnes of biosolids (dewatered sludge) were hauled to the City’s SWRF by a contracted waste hauler. The biosolids are weighed before being buried with incoming solid non-hazardous waste on a daily basis. Dewatered sludge will continue to be direct buried at the City’s SWRF in 2020. The WPCP expects to generate approximately 9000 tonnes of biosolids in 2020, assuming a similar wastewater flow.
Staff Organization
Infrastructure and Operations
General Manager – Kerri Marshall, P. Eng., MBA, FEC
Executive Assistant – Paula Ojala
Sustainability Coordinator – Amy Coomes
Climate Adaptation Coordinator – Jacob Porter
Environment Division
Water Pollution Control Plant
Plant Superintendent – Bob Bates, P. Eng.
Supervisor, Maintenance – Mike Brown
Supervisor, Operations – Mark Wilson
Accounting & Administration Clerk – Kristie Fisher
Chief Operator, Electrical – Dan Fulton
Chief Operator, Maintenance – Sal Piccolo
Chief Operator, Operations – Rod Cooper, Patty Wilson (Acting), Rick Sutton (Acting)
Environmental Inspector – Patrick McGuire
Janitor/Handyworker – Darrin White, Mario Colistro
Laboratory Technicians – Julie Carlin, Keenan Colosimo
Millwright Apprentice – Patty Wilson
Millwrights – Gord Belanger, Thane Gagnon, John Hrycyk, Mike Noga, Warren Perry
Operators – Keenan Colosimo, Jeff Coull, Rick Sutton, Patrick Melanson, Chris Unick, Phillip Kennedy, Shane Bureau, Patrick Melanson
Plant Electricians – Brian Dobson, Ron La Froye, Andreas Makrides
Relief Operators – Daniella N de Lima, Amanda Findlay
Director – Michelle Warywoda, P. Eng.
Administrative Assistant – Lynae Grace
Chief Chemist – Ian Morgan, Ph.D., P. Chem., C. Chem.
Manager – Compliance & Quality Control – Tony Santos
Planning & Research Analyst – Dan Currie, C.E.T.
Process Engineers – Lindsay Menard, P.Eng., PMP, Walter Turek, P.Eng.
Project Manager – Dave Dutchak
Training & Quality Assur-ance Coordinators – Terry Restoule, Shelby Jaspers
Water and Wastewater Engineer – Tom McConnell, P.Eng.
WATER POLLUTION CONTROL PLANT CITY OF THUNDER BAY ENVIRONMENT DIVISION 901 ATLANTIC AVE THUNDER BAY ON P7C 5K4
TEL: (807) 625-3370
THUNDERBAY.CA
WATER POLLUTION
CONTROL PLANT