Co-digestion of Source Separated Organic Food Waste: Status and Case Studies in the US, Canada, and Europe

This paper presents the findings from Phase 1 of the Water Research Foundation (WRF) project 4915 “Characterization and Contamination Testing of Source Separated Organic Feedstocks and Slurries for Co-Digestion at Resource Recovery Facilities”. This project aims to develop accurate and reproducible analytical methods for food waste characterization. Ultimately, the goal is to deliver practical guidance for the wastewater industry to create cost-effective and meaningful sampling strategies as well as acceptable minimum quality specifications for accepting SSO substrates for co-digestion. Phase 1 of the project consists of an international state-of-the-industry review of SSO co-digestion practices and experiences supported by a utility survey conducted among utilities in the U.S. and Canada. This paper summarizes the findings from the state-of-the-industry review which include current status of SSO feedstock codigestion, pretreatment practices, feedstock characteristics, quality standards, and data limitations. The paper also summarizes information from the utility survey including monitoring practices, and method limitations and needs. Finally, this paper presents a proposed tiered analytical strategy for SSO characterization for co-digesting utilities to streamline resources, and useful data that can be employed for operational decision making.