Biogas production after solid-liquid separation of dairy manure

ABSTRACT THE effect of solid-liquid separation of dairy manure was investigated. Three laboratory experiments were performed; the first used 10 L digesters, and the second and the third used 500 mL Erlenmeyer flasks as digesters. Manure fractions were digested at a temperature of 35 to 37°C. Biogas production was measured by water displacement. Specific biogas production rate (L/g VS fed) was greater from the whole manure than from the liquid fraction after separation. When the manure was separated into solids fractions and liquid fraction, the solids fractions had lower specific biogas production than the liquid fractions. No difference was found in the methane to carbon dioxide ratio of the gas produced from the various waste fractions.