Pennsylvania Digester Case Studies
Dairy: 2006 operational, Hillcrest Saylors Dairy Farms LLC, Somerset County, 608 milking and dry cows, slurry loop (modified plug flow), concrete top, two 130kW CHP units with power purchase agreement. Engine generator water and exhaust jackets heat digester, hot water for milking parlor, domestic hot water, space heat to milking parlor and office. Separate biogas storage building with 8 hours of biogas storage, digested separated solids used for bedding and soil amendments.
Dairy: 2008 operational, Reinford Farm, Juniata County, 470 milking and dry cows, complete mix, digested separated solids used for bedding, non-expanding flexible cover, recovered heat utilization includes engine generator water and exhaust jackets to heat digester, hot water for milking parlor, heat to milking parlor, calf milk pasteurizer, house, domestic hot water and shop floor heat. Waste heat from the engine radiator is used for drying grain. A 130kW CHP unit with power purchase agreement.
Poultry Facility: 1984 operational, Summer of 2008 after 24 years of operation the digester was shut down. Brendle Farm, Somerset County, 72,000 chickens (layers), slurry loop digester, oldest chicken digester in PA and the country, CHP unit with power purchase agreement, irrigates digester effluent.
Dairy: 1986 operational, Oregon Dairy LLC, Lancaster County, 385 dairy cows, modified plug flow (slurry loop) digester, one of the oldest digesters in PA and the United States, CHP unit with power purchase agreement.
Swine Facility: 2004 operational, Pine Hurst Acres, Northumberland County, 4,400 grow/finish hogs, complete mixed digester, automatic sorters in the food court, first farm to sell carbon credits on the Chicago Stock Exchange, CHP unit without power purchase agreement.
Dairy: 2006 operational, Penn England Farm, Blair County, 800 cows, complete mixed loop, uses digested separated solids for bedding, CHP unit with power purchase agreement, designed with a flat flexible cover to prevent wind damage.
Dairy: 2006 operational, Brookside Dairy, Indiana County, 425 cows, modified plug flow (slurry loop), re-injection of unused biogas mixes the digester, CHP unit with power purchase agreement.
Dairy: 2006 operational, Schrack Farms, Clinton County, <600 cows, plug flow (straight), digested separated solids used for bedding, digester built with an offal receiving pit, CHP unit with power purchase agreement.
Other Case Studies
Final Report: Haubenschild Farms Anaerobic Digester Updated August 2002 (39 pgs.) The report discusses digester types, benefits of anaerobic digesters, potential concerns, project description, system operations of the 750 cow plug flow digester, results, lessons learned and trends affecting future anaerobic digesters.
Methane Recovery from Animal Manures: The Current Opportunities Casebook (150 pgs.) A 1998 report discussing: lessons learned, digestion introduction, types and operation, 23 digester case studies (2 to 3 pgs. each) located throughout the United States. System designers, installers and other contacts are listed.
Langerwerf Dairy Digester Facelift: What We Found When We Took Apart a 16 Year-old Dairy Plug Flow Digester (7 pgs.): A 1998 AgSTAR document discussing the disassembly and inspection of a 400 cow plug flow digester, revealing settled sand accumulation, floating scum layer, and no corrosion to internal piping and concrete. Refurbishment was accomplished and startup was completed in a total downtime of 6 weeks.
Tinedale Farms Anaerobic Digestion - Final Report July 2002 (31pgs.): A technical report discussing the operation of a temperature phased anaerobic digester (TPAD) which is a digester designed with two tanks operating at two different temperatures; one thermophilic (133 OF) and one mesophilic (95 OF). It should be noted that this digester is now running as a single phase mesophilic digester.
Benefits, Costs and Operating Experience at Seven New Agricultural Anaerobic Digesters (June 1998, 9 pgs.): An AgSTAR document reporting on three dairy plug flow digesters in NY, OR, and CT; three swine covered lagoons in NC, VA, and IA; and one complete mixed swine in IL describing the digesters, benefits, revenues and costs.
Long Term Operation and Maintenance of a Digester at the Brendle Farms Poultry Operation (June 2004 Northeast Agricultural & Biological Engineering Conference (NABEC Paper # 04-0042) (8 pgs.): This paper discusses the operation of one of the few layer manure feedstock digesters in operation in the United States. Grit removal in a pretreatment tank is discussed along with digester capital costs, operation and maintenance and suggested future improvements.
Wisconsin Agriculture Biogas Casebook 2008 Edition