“As Seen in GEN—Flashback” Vol. 2, No. 3, May/June 1982
Chicken Waste to Methane: Anaerobic Trials at NC State
Dr. Jason Shih, a research scientist in the poultry science department at North Carolina State University, has developed an anaerobic digestor which economically converts chicken manure into usable methane (natural gas). Used in a commercial henhouse with 50,000 laying hens, the method could generate enough gas to heat 100 households, Dr. Shih estimates.
The unit is based on technology developed in Taiwan. Dr. Shih will deliver a paper on the system at an international seminar at Oxford University, Great Britain, this fall.
Several conferences this year have focused on newly developing anaerobic conversion techniques for producing methane from industrial and agricultural wastes. A series of new fermentations highlighted the Institute of Gas Technology's recent conference on Energy from Biomass and Waste, in Lake Buena Vista, Fla. Corning Glass Works is reportedly building a pilot plant for sewage conversion, based on immobilized methanogenic bacteria in a reactor designed by Corning's Dr. Ralph Messing.
Dr. Shih's digestor was designed and constructed over the course of a four-year research project funded by the Department of Energy Appropriate Technology Program, the North Carolina Agricultural Research Service and the North Carolina Energy Institute.
The fermentation occurs in two steps. Chicken manure is flushed into an insulated plastic bag, around which hot water circulates, serving as a heat exchange. Under tightly controlled conditions, thermophilic bacteria, which occur naturally in the intestines of chickens, break down large carbon compounds into acetates and short-chain fatty acids. In a second anaerobic fermentation, several strains of methanogenic bacteria—Dr. Shih uses 10 to 18 different active strains—convert the smaller compounds into methane.