Report on the design and operation of a full-scale anaerobic dairy manure digester. Final report

A full-scale anaerobic digester on the Monroe State Dairy Farm was operated and monitored for 24 months with funding provided by the United States Department of Energy, Fuels from Biomass Systems Branch. During the period of operation, operating parameters were varied and the impact of those changes is described. Operational experiences and system component performance are discussed. Internal digester mixing equipment was found to be unnecessary, and data supporting this conclusion are given. An influent/effluent heat exchanger was installed and tested, and results of the tests are included. Recommendations for digester design and operation are presented. Biological stability was monitored, and test results are given. Gas production rates and system net energy are analyzed. The economics of anaerobic digestion are evaluated based on various financing options, design scales, and expected benefits. Under many circumstances digesters are feasible today, and a means of analysis is given.