Agricultural Digester CHP

Penn State Ag Digester CHP

The operation of the Penn State Agricultural Digester and Combined Heat & Power (CHP) unit at the Agricultural Dairy is to receive animal waste from cows, chickens and pigs and anaerobically digest this waste. The products of digestion are biogas, which is used to produce electric power and heat through a CHP unit, and digested waste which is used as a soil amendment for crop agriculture application. The feedstock to the digester system was 28.5 tons/ day of sand laden cow manure, 18 tons/ day of diary barn milking parlor wash water, 5.5 tons/day of pig manure and flush water, and 60 lbs./ day of poultry manure. The manure is resident in the digester for a period of 14-16 days during which the digestion process takes place. At the same time, during digestion, the biogas produced is 55,000 cubic feet/day which is enough to continuously produce 110kW-hr of electricity and 130kW of recovered heat. The digested waste (digestate) is removed from the digester at a rate that is 97.8% of the rate additional of fresh waste.  The digestate is stored in post digestion storage tanks for distribution to local agricultural operators for their use.  WPPSEF provided $75,000 to co-fund the purchase of the 120 kWe biogas engine/ generator system used to produce electricity from the biogas. The CHP system started to receive biogas in August 2020.