Alternative Substrates for Digestion — Sometimes Manure Is Only… That!

Digestion of manure is used internationally and within the United States to produce biogas for the production of renewable energy. These systems are typically farm based, and have not been commercialized and operated by municipal agencies. Inland Empire Utilities Agency provides regional wastewater service and imported water deliveries to eight contracting agencies over a 242 square mile service mile area, located in the southwest corner of San Bernardino County, approximately 35 miles east of Los Angeles, California. IEUA conceived, constructed, and operated a full scale commercial manure digestion system in a municipal environment in Southern California. Ultimately, manure digestion proved to be unsuccessful in this environment for both technical and economic reasons. The design concepts, operating experiences, lessons learned and economic issues are reviewed.