Energy & Resource Recovery at Duffin Creek Water Pollution Control Plant

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1 Energy & Resource Recovery at Duffin Creek Water Pollution Control Plant WEAO Student Design Competition 2016 Amy Langford Patricia Wiebe Steven Zingaro

2 Duffin Creek WPCP Owned and Operated by Regional Municipality of Durham and Regional Municipality of York.

3 Project Objectives Phase 1: Preliminary design for (a) optimizing biogas production and use, and (b) energy recovery from incineration Phase 2: Conceptual design for two additional resource recovery opportunities

4 York Region Strategic Plan To provide long-term water and wastewater services for the communities of York Region, that are safe, well-managed, and sustainable, ensuring in so doing that the natural heritage and environment of the Region are preserved and protected Water and Wastewater Master Plan Update, Problem Statement

5 Current Energy Recovery Strategies at Duffin Creek WPCP Recycling effluent water Recovering ash product for cement Use of biogas for process & building heating Energy recovery turbines in incineration

6 Analysis of Existing Process Since Duffin Creek WPCP will not be included in Ontario s Cap-and-Trade Program, emissions reduction is not a financial incentive. (Minimum of 25,000 tonnes of direct emissions) Hydro Natural Gas 2014 Amount 65,430,781 kwh 3,171,579 m 3 Cost ~$7.2 Million $645, Equivalent CO 2 Emissions 45,118 tonnes (indirect) 5,900 tonnes

7 Increasing Biosolids Biosolids 30% to to AD AD 70% to Additional Fuel Analysis of Existing Process Anaerobic Digester Increase in Volatile Solids Concentration Decrease in Biosolids Heating Value

8 Analysis of Existing Process Phosphorus (P) Removal Two-point enhanced chemical removal Total P effluent concentration: 0.49 mg/l (max monthly average) Dewatered Biosolids Storage Tanks 19.6 hours storage capacity

9 Constraints & Criteria 1. Health & Safety Risks 2. Energy Recovery 3. Operation & Maintenance Requirements 4. Capital Costs 5. Emissions Reductions

10 Year Currently used: 2 dual-fueled boilers (digester gas and natural gas) for building & process heating Total Digester Gas (m 3 ) Digester Gas to Boilers (m 3 ) Digester Gas to Flaring (m 3 ) ,482, ,000 1,543, ,612, ,000 1,625,000

11 Boiler Specifications Specification Value Size of Boiler (HP) 200 required for operation of Boiler (m 3 /d) 9,106 Natural Gas required for Digester Heating (m 3 /d) 8,873 Operations and Maintenance Cost ($/yr.) $54,000 Energy Costs ($/yr.) mixing, natural gas, diesel fuel $750,000 Energy Recoverable from System (kwh/yr.) 0

12 Options for Further Energy Recovery Combined Heat and Power Systems to Natural Gas Quality Direct Digester Gas Sale to Industrial User Use as Vehicle Fuel

13 Use Decision Matrix Criterion Weighting Option 1: CHP Option 2: to NG Quality Option 3: Direct Sale Option 4: Vehicle Fuel Health & Safety 33% Energy Recovery 22% Operation & Maintenance 17% Capital Costs 17% Emissions 11% Totals (Weighting x Score)

14 Life Cycle Assessment Manager for Energy Recovery Developed by WERF and Hydromantis Environmental Software Solutions, Inc.

15 Scaled LCAMER outputs from 1-10 Engine Gas Microturbine Weighting Includes pre-treatment Cogeneration Turbinecosts Criterion Comparing CHP Technologies Molten Carbonate Fuel Cell Phosphoric Acid Fuel Cell Stirling Engine Size (kw) Health & Safety 33% Energy Recovery 22% Operation & Maintenance 17% Capital Costs 17% Emissions 11% Totals (Weighting x Score)

16 Chosen CHP Technology Specification Value Size (kw) 300 Capital Cost $5,400,000 required for operation of Fuel Cell (m 3 /d) 2,228 Natural Specification Gas required for Digester Heating (m 3 /d) 14,249 Value Operations CHP Size (kw) and + Maintenance Boiler Size (HP) Cost ($/yr.) $228, required for operation (m Energy Costs ($/yr.) mixing, natural /d) gas, diesel fuel 11,334 $485,000 Natural Gas required for Digester Heating (m Energy Recoverable from System ($/yr.) /d) 8,330 $3,100,000 Operations and Maintenance Cost ($/yr.) Greenhouse Gas Emissions Reduction (tonnes CO2 /yr.) $285,000 7,681 Energy Costs ($/yr.) mixing, natural gas, diesel fuel $730,000 Energy Recoverable from System ($/yr.) $1,810,000 Greenhouse Gas Emissions Reduction (tonnes CO2 /yr.) 3,715

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18 In 2010, Duffin Creek WPCP implemented an Infilco Degremont Thermylis process Dry Feed Rate (kg/hr) 4,375 Dry Solid Concentration (%) 28% Volatile Solids Concentration (%) 68% Dewatered BiosolidsTemperature ( o C) 21

19 Current System

20 Further Dewatering Alteration of Biosolids Dewatering biosolids further than the 27% that they are currently reaching Biosolids Composition Alter the biosolids composition to maximize heating value

21 Alteration of Biosolids These options were disqualified based on: Current pumping process optimized at 70/30 split (raw to digested biosolids) Slip-ring water currently added Centrifuges operating near maximum performance

22 Alteration of Process Organic Rankine Cycle (ORC) Generator Heat Pump District Heating

23 Decision Matrix From the decision matrix ORCs are the selected technology Criterion Weighting Option 1: ORC Option 2: Heat Pump Option 3: District Heating Health & Safety 33% Energy Recovery Operation & Maintenance 22% % Capital Costs 17% Emissions 11% Totals (Weighting x Score)

24 Organic Rankine Cycle ORC generators differ from steam cycles only in the working fluid ORC generators use organic fluids as opposed to water ORCs take advantage of low-grade heat sources

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26 Organic Rankine Cycle Typically ORC systems have efficiencies of 10-20% and can use heat sources as low as 67 C. kw thermal = 49,500,000 = 45,300,000 kj hr kj hr 4,200,000 kj hr /3600(sec hr )

27 Organic Rankine Cycle kw thermal = 12,600 kj sec kw electrical = 12, (kW e /kw t ) kw electrical = 1,260 kw e there is approximately 1,260 kw e waste heat available to recover

28 Organic Rankine Cycle HRS Clean Cycle Infinity Turbine Size (kw) Unit Price $562,000 $270,000 $405,000 $675,000 $1,330,000 Heat Exchanger $100,000 $81,000 $122,000 $273,000 $531,000 Installation $30,000 $41,000 $41,000 $270,000 $266,000 Operation & Maintenance $20,000 $7,000 $10,000 $17,000 $33,000 Savings ($0.08/kWh) $83,000 $35,000 $70,000 $175,000 $350,000 Payback Period

29 Organic Rankine Cycle Infinity Turbine ORC Size (kw) 500 ORC Unit Price $1,330,000 Heat Exchanger $530,000 Installation $266,000 Operation & Maintenance $33,000 Total $2,159, years Payback Period* 4.9 years 3.2 years *dependent on electricity prices

30 Process Flow

31 Updated Site Plan Phase I

32 - Two Additional Resource Recovery Opportunities Enhanced Biological Phosphorus Removal (EBPR) and Recovery Additional Storage Silos for Dewatered Biosolids

33 Phosphorus (P) is an non-renewable resource EBPR can be implemented at Duffin Creek WPCP through retrofitting current unit processes WAS and Primary Sludge separation Recycle streams Reactor tanks Enhanced Biological Phosphorus Removal (EBPR): UCT Process Effluent TP concentrations unaffected Fe 3 Cl chemical savings from EBPR

34 Enhanced Biological Phosphorus Removal (EBPR): UCT Process

35 Benefits of Phosphorus Recovery through OSTARA Technology Biosolids production is decreased by 10-35% Pearl TM 10,000 and WASSTRIP Crystal Green Fertilizer purchased by OSTARA to cover operating and maintenance costs OSTARA

36 EBPR and OSTARA Cost Required Retrofit Item Analysis Cost Piping (Materials and Installation) $890,000 Retrofitting Bioreactors $430,000 Ostara Pearl and accompanying systems Operations and Maintenance Cost ($/yr.) Total $11,000,000 - $16,000,000 $0 $ $17.3 million

37 EBPR and OSTARA Cost Saving Item Analysis Value Ferrous Chloride ($/yr.) Reduced Biosolids Handling (Predicted reduction in biosolids production from 10-35%) Total $2,700,000 per year $160,000 - $550,000 per year $2.9 - $3.3 million per year Estimated 4 6 year payback period

38 Additional Storage Silos for Dewatered Biosolids Two additional tanks 150 m 3 each Reduces the amount of incinerator shutdowns Reduced Carbon Emissions: 615 tonnes/year

39 Additional Sludge Storage Silos for Dewatered Sludge Item Value Storage tank (2 x 150 m 3 ) $3,500,000 Installation (30%) $1,050,000 O&M (no operating costs required) (2.5%) Total $101,250 $4.7 million Goal: Continuity of incinerator operation

40 Updated Site Plan

41 Overall Benefits of Phase I Designs Utilization: Electricity Generation $1.8 million/year and 3,715 tonnes CO 2 /year System: Waste Heat Usage $350,000/year and 3,750 tonnes CO 2 /year

42 Overall Benefits of Designs EBPR and P recovery: Reduced biosolids production Increases sustainability Storage Tanks Increases biosolids management capacity Decreases operation requirements, energy, and natural gas emissions

43 Thanks to: Acknowledgements Hongde Zhou, Ph.D., P.Eng., University of Guelph Robert Poisson, P.Eng., R.E. Poisson Engineering Inc Lauren Fillmore, WERF Hugh Monteith, Hydromantis Environmental Software Solutions Inc. Derek Lycke, OSTARA Marc Hunt & Jamie Hodd from Alfa Laval Inc.

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