Food Waste Co-Digestion at Water Resource Recovery Facilities: Business Case Analysis

Carol Adaire Jones, Craig Coker, Ken Kirk, and Lovinia Reynolds
Date Released
December 2019
Food Waste Co-Digestion at Water Resource Recovery Facilities: Business Case Ana

Co-digestion of food wastes with wastewater solids at water resource recovery facilities (WRRFs) can provide financial benefits to WRRFs as well as a broad range of environmental and community benefits. Co-digestion is a core element of the wastewater sector’s “Utility of the Future” initiative, which envisions a new business approach for pioneering WRRFs to create valuable energy and nutrient products via the recovery and reuse of residuals from the wastewater treatment process. With fewer than 1 in 10 WRRFs using anaerobic digestion to process wastewater solids, and about 1 in 10 of those co-digesting high strength organic wastes, there appears to be significant untapped potential for co-digestion. A contributing factor is the various financial, operational, regulatory, stakeholder/political, and organizational risks and impediments WRRFs may face with the adoption of co-digestion and energy generation projects, which are outside core wastewater treatment services.

With the goal of stimulating and informing further evaluation and adoption of co-digestion, this report provides

  • A diagnostic framework for WRRFs to analyze the opportunities and business case for co-digestion in their own organizational, market, and policy contexts and, if indicated, to develop a long-term business strategy that advances their mission and long-term goals (Chapter 3),
  • Dozens of case studies illustrating strategies WRRFs have used to successfully address the range of risks and impediments they face in adopting co-digestion, as well as WRRF decisions to not co-digest, or to dropout or cutback co-digestion (chapters 4-9, Appendix B, Appendix C),
  • Lessons learned from a public policy perspective (Chapter 10, complemented by Appendix A which outlines the wide range of policies that can affect the financial and technical efficacy of a project),
  • Lessons learned from a WRRF perspective, including factors associated with successful co-digestion programs, as well as best practices for creating a successful business strategy, and solutions to various widely cited impediments to co-digestion.
  • Additional resources for WRRFs to support their diagnosis of co-digestion opportunities (Appendices D-F).

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Chapter 1: Overview of the Report


Building a Business Case: Framework for Decision-Making

Chapter 2: WRRF Co-Digestion: Current Status, Policy Context, Drivers and Impediments

Chapter 3: Framework for Decision-Making to Adopt Co-Digestion

Diagnostic Screening Questions: Assessing Fit, Opportunities and Impediments for WRRF Food Waste Co-Digestion (compiled from Chapter 3)


Case Studies

Chapter 4: Victor Valley Regional Water Reclamation Facility, Victor Valley Regional Water Reclamation Authority, California

Chapter 5: Stevens Point Waste Treatment Plant, Public Utilities Department, City of Stevens Point, Wisconsin

Chapter 6: City of Dubuque Water and Resource Recovery Center, Dubuque Iowa

Chapter 7: Clearwater Road Wastewater Treatment Facility, Derry Township Municipal Authority, Pennsylvania

Chapter 8: Central Marin Sanitation Agency Treatment Plant, Central Marin Sanitation Agency, California

Chapter 9: Joint Water Pollution Control Plant, Sanitation Districts of Los Angeles County

Appendix B: Thumbnail Case Study Sketches

Appendix C: Profiles of Feedstock Suppliers


Lessons Learned

Chapter 10: State Profiles: Policy Portfolios and WRRF Co-Digestion Adoption

Chapter 11: WRRF Perspective: Lessons Learned



Appendix A: Diagnosing the Policy Context for WRRF Co-Digestion

Appendix D: Tools for Assessing the Business Case

Appendix E: Investment Decision-making: Financial and Triple-Bottom Line Criteria and Metrics

Appendix F: Federal and State Programs Providing Grants and Loans

Appendix G: WRF Research Projects on Co-Digestion


The Environmental Law Institute gratefully acknowledges the Water Research Foundation’s financial and administrative assistance in funding the project through which this information was discovered, developed, and presented.

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