Variation in Methane Yield from Anaerobic Digestion of Cattle Manure

There are many tests published on the methane yield of cattle manure, both using batch tests with inoculum and tests with continuously stirred tank reactors [CSTR]. These tests have a variation in methane yield of 130 - 300 l/kg volatile solids [VS], influenced by the freshness of the manure, diet of the cattle (composition of the manure), temperature of digestion, the type of inoculum, ratio between inoculum and manure, solids content and the length of the testing period. In most cases only a few of these parameters have been documented.