Co-Digestion of Organic Waste Products with Wastewater Solids (Interim Report)

This project furthers the understanding of co-digestion of organic waste with wastewater solids, quantifies the benefits of co-digestion, and provides answers to key questions to help overcome barriers associated with greater implementation of co-digestion programs at municipal WRRFs. The practice of adding waste organic feedstock directly to anaerobic digesters is becoming an attractive way for utilities to generate revenue from tipping fees while boosting biogas production. However, the practice is only used by about 20% of WRRFs with AD due to the uncertainty on how to proceed without causing digester upset. Through lab, pilot-scale, and a study of a full-scale facility, this research addresses some of these operational issues. Includes an Excel-based Economic Model that utilities can use to determine an appropriate tipping fee for handling this waste in the digesters often the source of additional revenue which makes these energy recovery project viable.