Nutrient recovery at the ashbridges bay wastewater treatment plant WEAO SDC 2015 Tania Good morning everyone, we hope you are enjoying the conference. We are all here today to talk about Nutrient Recovery at the Ashbridges Bay Wastewater Treatment Plant. My name is Tania Farah, this is Amal Ghamrawi and Rose Zhao who will now introduce us to the Ashbridges Bay Wastewater Treatment Plant. Tania Farah Amal Ghamrawi David Tran Rose Zhao

Ashbridges Bay wASTEwater Treatment Plant Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Ashbridges Bay wASTEwater Treatment Plant ECA Effluent Discharge Limits Parameter Limit SS [mg/L] 25 SS Loading Rate (kg/day) 20,450 CBOD5 [mg/L] CBOD5 (kg/day) pH 6 – 8.5 TP [mg/L] 1 TP Loading Rate (kg/day) 818 E-Coli [CFU/100 mL] 200 ABTP Fast Facts Location City of Toronto Effluent Discharge Lake Ontario Nominal Capacity 818 MLD Equivalent Population 1,524,000 Sewershed Area Serving 25,000 ha Rose ABTP is located in Toronto and it discharges effluent into Lake Ontario. It is the largest secondary WWTP in Canada, with a nominal capacity of 818 MLD and an approximate sewershed of 25,000 ha. It is a conventional activated sludge plant The influent to the plant also include sludge flows from two other plants in Toronto—Humber Treatment Plant and North Toronto Treatment Plant. These are the discharge effluent guidelines that ABTP is required to meet and are currently meeting. The plant has high nitrogen loading in the mainstream because it accepts sludge from two other plants and recycles the anaerobic digestate EFFLUENT DISCHARGE REQUIREMENTS.

Toronto Water Strategic Plan Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Toronto Water Strategic Plan Mission Statement Guiding Principles Provide quality water services to the Toronto community while protecting public health, safety and property in an environmentally and a fiscally responsible manner Continuous Service Delivery Improvement Financial Vitality, Viability and Sustainability Operational Excellence Infrastructure Management Employer of Choice Rose ABTP is located in Toronto and it discharges effluent into Lake Ontario. It is the largest secondary WWTP in Canada, with a nominal capacity of 818 MLD and an approximate sewershed of 25,000 ha. It is a conventional activated sludge plant The influent to the plant also include sludge flows from two other plants in Toronto—Humber Treatment Plant and North Toronto Treatment Plant. These are the discharge effluent guidelines that ABTP is required to meet and are currently meeting. The plant has high nitrogen loading in the mainstream because it accepts sludge from two other plants and recycles the anaerobic digestate EFFLUENT DISCHARGE REQUIREMENTS.

ABTP Current initiatives Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion ABTP Current initiatives Water Quality Improvement Resource Recovery Initiatives Process changes to encourage nitrification Increased SRT and DO concentrations Improved DO control instrumentation programming Additional 10 million kWh is used per year Recycling of effluent water for non-potable use Use of digester gas for process and building heat Beneficial use of biosolids Rose ABTP is located in Toronto and it discharges effluent into Lake Ontario. It is the largest secondary WWTP in Canada, with a nominal capacity of 818 MLD and an approximate sewershed of 25,000 ha. It is a conventional activated sludge plant The influent to the plant also include sludge flows from two other plants in Toronto—Humber Treatment Plant and North Toronto Treatment Plant. These are the discharge effluent guidelines that ABTP is required to meet and are currently meeting. The plant has high nitrogen loading in the mainstream because it accepts sludge from two other plants and recycles the anaerobic digestate EFFLUENT DISCHARGE REQUIREMENTS. 4

PHASE I PHASE II Objective of Project Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Objective of Project PHASE I PHASE II Reduce the TKN and ammonia of the centrate streams to approaching plant influent levels. Two additional areas in which the plant could adopt a resource recovery approach to: Benefit the operations Lessen the environmental impact Reduce the cost of treatment Stream TKN (mg/L) Ammonia (mg/L) Influent 50.9 25.4 Centrate 907 590 Amal ABTP is located in Toronto and it discharges effluent into Lake Ontario. It is the largest secondary WWTP in Canada, with a nominal capacity of 818 MLD and an approximate sewershed of 25,000 ha. It is a conventional activated sludge plant The influent to the plant also include sludge flows from two other plants in Toronto—Humber Treatment Plant and North Toronto Treatment Plant. These are the discharge effluent guidelines that ABTP is required to meet and are currently meeting. The plant has high nitrogen loading in the mainstream because it accepts sludge from two other plants and recycles the anaerobic digestate EFFLUENT DISCHARGE REQUIREMENTS.

PHASE I Planned approach Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion PHASE I Planned approach Centrate Treatment Options Phase I-1 Phase I-2 Resource Recovery Treatment Ammonia Stripping Amal Ion Exchange Struvite Recovery 6

Centrate Characteristics Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Centrate Characteristics Centrate Characteristics Parameter Value Nominal Centrate Flow (L/s) 84 (8 MLD) TKN (mg/L) 907 Ammonia (mg/L) 590 Phosphorous (mg/L) 139 TSS (mg/L) 1959 Amal The activated sludge is settled in the final clarifiers, and then is thickened through dissolved air flotation. It then enters anaerobic digestion where organic matter is broken down, and where bound ammonia is released. This is then dewatered through the use of centrifuges and then the liquid stream is recycled into the secondary treatment. The advantages of centrate only treatment include a concentrated stream of nutrients and a smaller volume – a nominal flow of 8 MLD vs. 818 MLD. The Phosphorous content in the centrate is assumed to be 20% of the influent.

Nutrient Recovery Options Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Nutrient Recovery Options Up to 96% of N as NH3/NH4+ as Ammonium Nitrate/Sulphate Fertilizer Requires: T>60°C Problems: carbonate scaling, noise, air pollution and high pH Ammonia Stripping Up to 97% N as NH4+ or up to 90% N as NO3 as a fertilizer Requires: extensive pretreatment Problems: complex bed regeneration and extensive pretreatment Ion Exchange Up to 90%-P & up to 40%-NH3 as slow-release fertilizer Requires: addition of magnesium source and pH≈7-8 Problems: possible crystallization in pipes Struvite Recovery amal Ammonia Recovery: Ammonia stripping recovers nitrogen only, up to 80-90% N recovery through the volatilization of gaseous ammonia (WERF, 2014). The products that can be recovered are ammonium nitrate and ammonium sulphate. Air stripping only removes ammonia and ammonium from wastewater, it does not recover organic N or nitrate. The pH requirements of the system require it to be at least greater than 10 and an operating temperature of at least 60 degrees C. Ammonia stripping is done via air, steam or vacuum which all require energy. The operating costs are high. There are a lot disadvantages associated with ammonia recovery. High operation and maintenance costs pH and temperature of air and water must remain stable and high Large air requirements (for air stripping) Higher pH can absorb CO2 from the air and cause carbonate scaling –which may or not be removed Water must be re-pumped to stripping tower In freezing conditions, air must be sufficiently heated –fogging and icing decrease removal efficiency Ammonia is discharged to the environment and air pollution problems may arise from ammonia and sulphur dioxide reactions Noise may be an issue High pH wastewater can corrupt the wood packing in stripping tower Ion Exchange: Ion exchange for nitrogen control is when, “ions of a given species are displaced from insoluble exchange materials by ions of a different species in solution,” (WERF, 2014), ammonium is removed. It has not really been applied in wastewater treatment due to concerns about the regeneration bed, complexity and high costs. Ion Exchange has been reported to be 15 times the cost of nitrification and denitrification, depending on the lime added. Struvite Recovery: Struvite is a crystalline material that commonly precipitates within wastewater treatment plants, often causing issues with the clogging of pipes and pumps. Direct extraction of this struvite as P from biosolids can reduce the problem and recover P and N. It requires the addition of a magnesium source and a pH adjustment Struvite recovery is the most feasible out of all of these processes and has been demonstrated full scale at several plants. Has several proprietary processes.

Struvite Recovery options Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Struvite Recovery options Factor DHV Crystalactor® Multiform Harvest Inc. Crystallizer NuReSys® Process Ostara Pearl® Process Pacques PHOSPHAQ™ Country 5 10 Reactor Type Chemicals Used HRT 15 8 P Reduction 7 NH3-N Reduction Full Scale Plants 3 2 Odour Control Capital Costs 20 9 TOTAL 100 755 670 440 770 465 amal Struvite Recovery is provided through various proprietary processes.

oSTARA PEARL® PROCESS Mg+2 + NH4+ + PO43- + 6H2O  MgNH4PO46 H2O Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion oSTARA PEARL® PROCESS Mg+2 + NH4+ + PO43- + 6H2O  MgNH4PO46 H2O The OSTARA Advantage Up to 94% PO43- and 30% NH3 removal efficiencies Canadian 8 Full Scale Municipal Installations Renewable fertilizer production Reduces: Chemical use Nutrient loads Operation and maintenance costs Greenhouse gas emissions Process Requirements MgCl2 6000 kg/day NaOH 800 kg/day Heat 16 GJ/day Power 2350 kWh/day amal The formation of struvite occurs under favorable conditions, including when concentrations of soluble magnesium (Mg+2), ammonium (NH4+), and orthophosphate (PO4-3) exceed levels which promote the formation of crystals, sometimes referred as super- saturation. These three ions have to be in a molar ratio of 1:1:1. Ostara

OSTARA PEARL® PROCESS 25% Influent P Improved biosolids cake 4% increase in solid content 20% decrease in volume OSTARA PEARL® PROCESS 25% Influent P Waste Activated Sludge Stripping To Remove Internal Phosphorous Amal 20% Influent P Ostara

EXPECTED EFFLUENT CHARACTERISITCS Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion EXPECTED EFFLUENT CHARACTERISITCS WASSTRIP® Flow (m3/d) 3391 TSS (mg/L) 500 PO4-P (mg/L) 374 NH3-N (mg/L) 30 Pearl® Effluent Flow (m3/d) 10665 TSS (mg/L) 1495 PO4-P (mg/L) 34 NH3-N (mg/L) 331 TKN (mg/L) 547 Objective Influent Centrate Ammonia (mg/L) 25.4 590 TKN (mg/L) 50.9 907 Centrate Flow (m3/d) 7273 TSS (mg/L) 1959 PO4-P (mg/L) 139 NH3-N (mg/L) 590 TKN (mg/L) 907 Amal Ostara 2 Pearl 10000 Reactors 12

Nutrient removal Centrate Treatment Options Resource Recovery Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Nutrient removal Centrate Treatment Options Resource Recovery Biological Treatment Nitrification-Denitrification Tania Nutrient removal consists of two different treatments. One approach resource recovery, which is the physical or chemical treatment that Amal was just discussing, and the other is biological treatment. This treatment removes nitrogen out of wastewater before it is discharged into the water, through the use of microorganisms. That being said, there are multiple biological processes such as: Nitrification-Denitrification Nitritation-Denitritation Partial Nitritation-Anammox Nitritation-Denitritation Partial Nitritation-Anammox

Biological Treatment of Nitrogen Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Biological Treatment of Nitrogen Biological 1 mole Nitrate 40% C 25% O2 Nitrification-Denitrification Nitritation-Denitritation 1 mole Nitrite 1 mole Nitrite 60% C 75% O2 Partial N-Anammox Tania Nitrification-Denitrification is the conventional process, making it the least efficient. As you can see in the figure, the first half of this process requires 100% oxygen and the second half requires 100% of a carbon source. 1 mole Ammonia ½ mole Nitrogen Gas

Biological Treatment of nitrogen Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Biological Treatment of nitrogen Biological 1 mole Nitrate 40% C 25% O2 Nitrification-Denitrification Nitritation-Denitritation 1 mole Nitrite 1 mole Nitrite 60% C 75% O2 Partial N-Anammox Tania Nitritation-Denitritation is a more advanced process. It removes a part of the conventional process, making it efficient. Compared to the conventional, this process requires 75% oxygen and 60% of a carbon source. 1 mole Ammonia ½ mole Nitrogen Gas 15

Biological Treatment of nitrogen Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Biological Treatment of nitrogen Biological 1 mole Nitrate 40% C 25% O2 Nitrification-Denitrification Nitritation-Denitritation 75% O2 ½ mole Nitrite 1 mole Nitrite 60% C 40% O2 Partial N-Anammox Tania The most advanced treatment is Partial Nitritation-Anammox, where Anammox stands for anaerobic ammonia oxidation. It reduces the process by half, and only requires around 40% of oxygen. It does not need a carbon source, making it the most efficient treatment out of the biological treatments. The nitrogen gas is produced under anoxic conditions with the use of autotrophic bacteria known as anammox bacteria. 1 mole Ammonia ½ mole Nitrogen Gas 16

Partial Nitritation-Anammox Processes Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Partial Nitritation-Anammox Processes DEMON® SBR Partial Nitritation-Anammox ANITATM Mox MBBR Tania There are multiple configurations designed for this process: DEMON® Suspended Growth Sequence Batch Reactor (SBR) Process ANITATM Mox Moving-Bed Biofilm Reactor (MBBR) Process Two-Stage SHARON®-ANAMMOX® Process 2-Stage SHARON®-ANAMMOX® 17

Partial Nitritation-Anammox Processes Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Partial Nitritation-Anammox Processes DEMON® SBR ANITATM Mox SHARON®-ANAMMOX® TN Removal (%) 85 80 90 Energy (kW-h kg-1) 1.0-1.3 1.45-1.75 4.17 Start-Up Time (Months) 2-5 3-4 3-5 Operator Attention High Low Maintenance Medium Tania All three of these processes have a common outcome. The difference is their demands. The best two alternatives are DEMON and ANITATM Mox. There is not a large energy demand difference nor TN removal between the two, thus those cost differences will not be great. Now ANITATM Mox has a higher energy demand, however, it requires less operator attention and lower maintenance. These demands contribute to annual costs, making ANITATM Mox the better option. 18

Preliminary Reactor Characteristics Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Preliminary Reactor Characteristics Soluble BOD Removal ANITATM Mox Nitrification Volume 1200 m3 3500 m3 900 m3 SWD 5.0 m Air Flow Requirement 6500 Nm3/h 14000 Nm3/h 5000 Nm3/h Effluent NH4-N 441 mg/L 72 mg/L 30 mg/L Effluent TKN -- 157 mg/L 111 mg/L Effluent TSS 1500 mg/L Alkalinity Consumption 1600 mg/L 300 mg/L Dissolved Air Flotation Unit Effluent TKN 40-50 mg/L Tania According to Mr. Pearce, the Sales Director at Veolia Water Technologies, the ANITATM Mox system design would be composed of 3 reactors in series: Reactor 1: Soluble BOD Removal Reactor Reactor 2: ANITATM Mox Reactor Reactor 3: Nitrification Reactor The goal of the first reactor is to remove the soluble biodegradable carbon upstream of the ANITATM Mox reactor. This is done to prevent competition between the heterotrophic biomass and the anammox bacteria. An additional third reactor is needed to complete nitrification due to the treated effluent objective being 51 mg/L TKN. In order to reach that effluent TKN requirement, a solid/liquid separation system, typically a DAF unit is needed. With 90% TSS removal, the DAF effluent TKN would be about 40-50 mg/L. Dissolved air flotation (DAF) is a water treatment process that clarifies wastewater by the removal of suspended matter. The removal is achieved by dissolving air in the wastewater under pressure and then releasing the air at atmospheric pressure in a flotation tank. The released air forms tiny bubbles which adhere to the suspended matter causing it to float to the surface where it is then removed by a skimming device. Soluble BOD Removal Reactor ANITATM Mox Reactor Nitrification Reactor Dissolved Air Flotation Unit 19

Lessen Environmental Impact Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Design BASIS TN removal in addition to ammonia removal Improved final effluent Improving Operations Reduce Cost and Energy Ferric chloride eliminated Coarse to fine diffusers Non-chemical sludge Less sludge volume Safer to use on land Lessen Environmental Impact rose Requirement for: Struvite Recovery Resource Recovery 20

PROCESS SELECTED: A2O NMLR Secondary Effluent Influent Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion PROCESS SELECTED: A2O NMLR Secondary Effluent Influent Secondary Clarifier Anaerobic Anoxic Aerobic rose The treatment process applies anaerobic, anoxic, and aerobic sequence with sludge and internal cycle. Nitrate is recycled from the aerobic zone to the anoxic zone for denitrification. The use of the anoxic zone minimizes the amount of nitrate fed to the anaerobic zone in the return activated sludge Anaerobic and anoxic will be added to retrofit the existing nitrification system; The existing plant does not require denitrification; however, anoxic zone is retrofitted to the treatment to ensure reliability of the anaerobic zone and process efficiency. To achieve sufficient nutrient removal, reactor sizing and performances is determined base on mass balance of the influent characteristic and typical design parameters. RAS VFA WAS 21

DESIGN SPECIFICATION 25.4% 1.5 h 25.4% 1.5 h 49.2% 2.9 h Parameter Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion DESIGN SPECIFICATION 25.4% 1.5 h ANAEROBIC 25.4% 1.5 h ANOXIC Aeration Tanks 49.2% AEROBIC 2.9 h Parameter Value Total Volume 201,902 m3 Total HRT 5.9 h RAS 490,800 m3/d MLSS 3,000 mg/L Loading Current A2O TKN 9.72 mg/L 1.0 mg/L Ammonia 7.72mg/L < 1.0 mg/L TN 25 -30 mg/L 10 mg/L rose 22

ANITATM Mox Overall Benefits Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion ANITATM Mox Overall Benefits Overall project scope: ≈ $20-25 million Service Life: >20 years No additional chemicals No carbon source pH is self-regulated DO is automatically adjusted No heavy maintenance Simple operation Tania The overall project scope of ANITATM Mox, including construction and installation: ≈ $20-25 million The service life of carries with normal use in a steel tank is more than 20 years and more than 15 years in a concrete tank with smooth walls. And just a quick recap: No additional chemicals are needed once the starting period is over, no carbon source is needed, pH is self-regulated, DO is automatically adjusted. Does not require any heavy maintenance; all of the online sensors need to be calibrated regularly, but the equipment inside the reactor are maintenance-free. After start-up, the process is operated automatically from the programmable controller, making it simple for an operator to control the process operation. 23

Ostara Overall benefits Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Ostara Overall benefits Ostara Savings Ferric Chloride Elimination $1,259,000 WAS Thickening Polymer $138,000 Biosolids Dewatering Polymer $775,000 Sludge Handling and Disposal $2,467,000 N Removal $317,00 Capital Cost of Ostara:$20 million Includes 2 Pearl® 10000 Reactors, a building and WASSTRIP® Tank Expected Annual Savings: $5 million Expected Payback Period: 4-6 years Amal With the implementation of the WASSTRIP® and Pearl® process, anaerobic digestion will become more efficient and most plants have seen about a 15% reduction in sludge production. Therefore costs for sludge handling costs, dewatering and thickening polymers will be reduced. Additionally, for every kg of ammonia recovered in the Pearl® Process it is approximated that at least $1 can be saved on power costs. It is assumed that the plant spends around $200/tonne for sludge handling and disposal. The thickening polymer reduction is solely based on the reduction of chemical sludge produced from switching to Bio-P. While the dewatering polymer is savings from the anaerobic digestion improvement and the decrease in chemical sludge. ABTP Expected Production: 15.2 tonnes/day Crystal Green® Fertilizer Ostara WERF, 2014 24

A2/O Overall Benefits Estimated Annual Savings: $3.6 million Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion A2/O Overall Benefits Estimated Annual Savings: $3.6 million Savings not quantified: switching from coarse to fine air bubble diffusers A2O Savings Ferric Chloride Elimination $1,259,000 WAS Thickening Polymer $238,000 Biosolids Dewatering Polymer $500,000 Sludge Handling and Disposal $1,592,000 Amal 25

Updated Schematic of ABTP Introduction Phase I Nutrient Recovery Nutrient Removal Phase II: Resource Recovery Overall Benefits Conclusion Updated Schematic of ABTP Phase II Phase I-2 Phase I-1 rose

Acknowledgements Dr. Rajesh Seth University of Windsor Associate Professor Department of Civil and Environmental Engineering Faculty Advisor Dr. Edwin Tam Sailesh Singh Golder Associates Water Treatment Engineer Industry Advisor Michael Reaume Stantec Consulting Engineer in Training Derek Lycke Ostara Nutrient Recovery Technologies Technical Director, Nutrient Recovery Solutions David Pearce Veolia Water Technologies Sales Director