Mr. Tom Noyes, OSU Extension Educator, Wayne County, The Ohio State University
A bus-load of dairy producers, OSU research and Extension faculty, students, and agri-business people took a one day tour to Matlink Dairy. Located in Clymer, NY (the very southwest corner of New York) just outside the village of Clymer, the 600+ cow dairy farm needed to make improvements in the dairy manure management and handling area. The manure generated at Matlink Dairy was stored in a lagoon and spray-irrigated on the ground in March, April, and November. With the farm just upwind from the village, it quite often caused an odor problem. There was also a possibility that leaching of manure into the ground water was causing an increase in the nitrate-nitrogen concentration.
With support from the New York State Energy Research and Development Authority
(NYTSERDA), Ted Mathews, owner of Matlink Dairy, began construction of an anaerobic digester in 2000 and completed it in 2001. In addition to the manure from the cows, other feedstock to the digester included food wastes. Currently, liquid wastes from cheese plants and fruit juices are mixed with the manure. This increases the biogas production with higher methane content.
Heat and Electricity Generation
Biogas flow from the digester is used by the engine generator at a rate of approximately 76,400 ft3/day or about 113 ft3/cow/day. This biogas consists of methane (about 65%), carbon dioxide (about 35%), a small amount of sulfide compounds, and other trace gases. The biogas is collected and fed into a Waukesha engine attached to a Marathon generator (130 KW) that uses 22-25 ft3/KWH. The engine will operate 90-95% of the available hours per year.
This engine-generator set produces about 884,000 KWH/year, which meets the electricity needs for the dairy farm and provides some excess electrical power for sale to the local utility, Niagara Mohawk. The heat generated also provides hot water to heat the digester and other on-farm needs which saves the farm over $500 per month.
Accepting food wastes is profitable. The tipping fees make the manure treatment system a profit center for the farm. The food wastes are high in energy, having three times the gas production per unit of mass than manure; yet, the nutrient content is comparable to manure so imported nutrients are kept low. The increased gas production leads to increased electric generation. After digestion, the treated slurry is pumped to a screw press slurry separator. The separated solids are composted. Up to 65% of the composted solids are used on the farm, and the remaining solids sold at $5/yard can generate revenue of $500/month. The anaerobic digester - electric generating system is a win-win situation for Matlink Dairy.