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Anaerobic digestion is a method for decomposing organic matter, producing in the process, biogas, which is mostly methane. This process can be used to eliminate or reduce disagreeable and often environmentally harmful characteristics of wastes. During the autumn of 1984, the University of Maine began operation of an anaerobic digestion unit acquired from Agway, Inc., a large Northeastern agricultural cooperative. This system, installed at the Witter Animal Science Center, decomposes animal manures and ultimately produces electricity and hot water. A by-product of the system is a fertilizer with characteristics superior to fertilizers produced from biological wastes that have not undergone a process of anaerobic digestion. The research objectives were to (1) construct an economic-engineering model representing the waste to energy system, (2) quantify the benefits and costs of the system, (3) estimate the cash flows accruing over the lifespan of the system, (4) evaluate the model to determine the net present value of the system, and (5) evaluate alternative scenarios to determine the effect on economic feasibility.
Maine Agricultural Experiment Station
Anaerobic digestion, dairy farms, Maine
Criner, G.K., D.F. Silver, F.R. King, J.D. Leiby, and A.S. Kezis. 1986. An economic analysis of a Maine dairy farm anaerobic digester. Maine Agricultural Experiment Station Bulletin 816.