Recommendations for The Analysis of Source Separated Organic Food Waste to Help Inform the Design and Operation of Co-digestion Facilities

Most food waste generated in the United States ends up in landfills and contributes substantially to methane release. Anaerobic digesters at Water Resource Recovery Facilities (WRRFs) often have excess capacity that can handle the addition of a co-substrate rich in nutrients and chemical energy for increased biogas generation. Source separated organics (SSO) vary seasonally and geographically making characterization a vital step to facilitate co-digestion at WRRFs. Analytical methods proposed for the characterization bioslurries from SSO food waste were adopted in this project from established methods for wastewater, sludge, soil, and compost analysis. These methods were then used to characterize five SSO bioslurries from different utility and commercial production locations in North America. The results showed that the proposed analytical methods result in a variability of less than 20% for methods using fast testing kits and variabilities below 1% for analytical methods using probes. Test methods were used for quantifying microplastics in SSO food waste which allows for a quick screen of the degree of plastic contamination in co-substrates. The bioslurry properties were used to develop guidance for the design and operation of co-digestion at WRRFs using SSO substrates.