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Water Research Foundation Project #4915: Characterization and Contamination Testing of Source Separated Organic Feedstocks and Slurries for Co-Digestion at Resource Recovery Facilities

Authors: Tanja Rauch-Williams

Water Research Foundation

Research led by Carollo’s Tanja Rauch-Williams is tackling the challenges associated with source separated (SSO) feedstock co-substrate. The recently completed Water Research Foundation Project #4915 examines the characterization and testing of SSO feedstocks and slurries for co-digestion at resource recovery facilities. The study’s findings include crucial guidelines for SSO feedstock characterization, standardized sampling protocols for monitoring feedstocks, and minimum feedstock quality requirements.

Read the full study


A key challenge with source separated organic (SSO) feedstock co-substrate is that its composition, quality, and characteristics differ between geographical locations and can change over time. This causes challenges and uncertainties for pre-treaters, substrate brokers, facilities accepting this material, operators, engineers, and regulators. This project addressed these challenges by establishing guidelines for characterizing SSO feedstocks, standardizing sampling protocols for rapid and comprehensive monitoring of feedstocks, and developing recommendations for minimum feedstock quality requirements. In addition, the research team hosted a workshop focused on developing relevant terminology, analytical metrics, and characteristics of high strength feedstock in North America. Project findings are captured in four reports, posted below under Resources:

  • DRPT-4915A: Literature Review
  • DRPT-4915B: Provides practitioners with guidance to assess the characteristics of different types of SSO feedstock and their impact on process performance, stability, regulatory compliance, and the quality of end products, including biosolids, biogas and air emissions, and final effluent.
  • DRPT-4915C: Provides operators with recommendations on the sampling, preservation, and analysis of these parameters in SSO food waste feedstock to help overcome common issues with this challenging waste stream.
  • DRPT-4915D: Workshop Summary Report.