Curbing Greenhouse Gas Emissions Through Co-Digestion

Transcription

1 Curbing Greenhouse Gas Emissions Through Co-Digestion Ed Dujlovic City of Stratford Indra Maharjan Ontario Clean Water Agency Michael Theodoulou Suez Water Technologies & Solutions March 22, 2018

2 Presentation Outline Co-digestion for Energy Neutrality Co-location vs. Co-digestion Environmental Benefits through GHG Emission Reductions Stratford Energy Positive Co-digestion Project Blueprint for the Future 2

3 Co-digestion for Energy Neutrality Consumption Production Conventional WWTP Biological Hydrolysis Sludge Only Biological Hydrolysis + Co- Digestion Organic Waste 3

4 Co-located Anaerobic Digestion Biological Hydrolysis 4

5 Co-location in Practice Bristol Sewage Treatment Works at Avonmouth Advanced Anaerobic Digestion Energy Centre 1 Install Advanced Anaerobic Digestion Biological Hydrolysis 2 Converted Digester Capacity 3 Implement Advanced Anaerobic Digestion for Biowaste 4 5 Re-allocated existing digester volume for biowaste digestion Utilize Existing CHP s to make Renewable Energy

6 View of the AD Facility of the Bristol Sewage Treatment Works at Avonmouth Food Waste Plant & Dedicated Food Waste AD Monsal 42 Biological Hydrolysis Produces 5.75 MW of Renewable Electricity, covering full WWTP parasitic load and Exporting the Excess 6

7 Small Plant Implementation of Co-digestion For smaller plants, it likely will not be feasible to have duplicate process steps and therefore true co-digestion would be utilized. Enhancement of AD process through the implementation of BH for wastewater sludge Reception of food waste, separation and pre-treatment on-site at the WWTP Pasteurization of all process streams in the same pasteurization volume Use of common AD volume for true co-digestion of wastewater sludge and food waste Blended residuals treatment including post-digestion screening and potential dewatering Marketing of the end blended biosolids/digestate product as a CFIA fertilizer Convert all biogas into Renewable Energy - Electricity and/or Renewable Natural Gas (RNG) 7

8 Co-digestion Model BH 1.5 DAYS AT 42⁰C 8

9 Greenhouse Gas Emission Reductions Through Co-digestion Divert Waste From Landfill Offset Natural Gas with RNG 9

10 Putting into Practice: Stratford, ON Co-digestion Project Producing RNG Organic Waste Stratford WPCP Rated Capacity: 30,660 m 3 /d Re:Sep 2.0 Organic Waste Separation Biogas Biogas Upgrading RNG Pipeline Injection Stratford WWTP Sludge (PS & WAS) Mesophilic Anaerobic Digester (Existing) CFIA Biosolids to Land Application Biological Hydrolysis Mesophilic Anaerobic Digester (Existing) Reducing GHG Emissions by 49,000 TCO 2 eq/yr 11

11 Impact on Digester Utilization Existing Design Proposed Design Biogas at Biogas at VS Loading VS Loading 60% (CH4) 60% (CH4) tpd kg/d NM3/d tpd kg/d NM3/d Primary solids Secondary Soludge Food Waste Liquid Wastewaste Total Units Existing Proposed Volume m Loading kg VS/m3/d

12 Biogas Upgrading to RNG CH 4 recovery rate > 99.3% Compressor Stage 1 Stage 2 Conditioned Biogas 96-98% CH 4 To pipeline injection Stage 3 To the atmosphere Offgas %CH 4 <0.5% The CO2 is separated from the methane 13

13 Environmental Benefits GHG Emission Reductions Diversion of Waste from Landfill (IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories, Chapter 5 Waste) Offset of Fossil Fuel Natural Gas (2006 IPCC Guidelines for National Greenhouse Gas Inventories, Chapter 2 Stationary Combustion ) TCO 2 eq / Tonne Solid Food Waste Diverted TCO 2 eq / M 3 RNG Produced

14 Estimated GHG Emission Reductions Stratford, ON Co-digestion GHG Reduction Estimates (TCO 2 eq) Direct (Landfill Diversion) Indirect (NG displacement by RNG) Total Emission Reductions Annually By 2020 By 2030 By ,012 90, , ,240 3,939 7,878 47,268 78,780 48,951 97, , ,020 15

15 Stakeholders in Stratford City of Stratford (Infrastructure, Emitter) RNG Offtake Contract (Union gas) Pioneering initiatives like these are not only beneficial for the municipality s system, but also set a great example for the rest of the province. Dianne Saxe, Environmental Commissioner of Ontario Feedstock Contract OCWA (Operator) Suez (Technology Provider) Permitting (MOECC) Awarded $5MM CDN through Target GHG OCE (Partial Funding) 16

16 Value Chain in a Circular Economy/Co-benefits 40% Waste Diversion/ Extended Landfill Life Organic Waste Infrastructu Maximize re Utilization Existing Assets Provides Options to Municipalities introducing Residential SSO Collection Nutrients to Agriculture Reducing the import of synthetic fertilizers CFIA CFIA Fertilizer to Land RNG GHG Reductions by reaching 3.5 Million Households with RNG 17

17 Blueprint for the Future 48,951 TCO 2 eq/yr 869,790 TCO 2 eq/yr 1,586,090 TCO 2 eq/yr 2.6 Million + TCO 2 eq/yr Repeatable Model for Suez, OCWA & Utility to Bring to WWTPs across Ontario Supporting the Province s Climate Change Action Plan & Upcoming Landfill Diversion Regulations 18

18 Summary Co-digestion can be a valuable means to realize the full potential of existing AD assets at Municipal wastewater treatment plants Implementation of co-digestion can have a significant impact on biogas production from existing assets Co-digestion can result in substantial environmental benefits, such as GHG emission reductions. The Stratford Co-digestion project is a blueprint for many more Municipalities to implement across Canada and the Rest of the World 19

19 Thank You