Improvement of methanogenesis from cow dung and poultry litter waste digesters by addition of iron.

When 50MM FeSO4 was added to cow dung and poultry litter waste which had been processed in daily-fed batch digesters, digesters subsequently unfed showed a faster conversion of substrate and overloaded digesters stabilized within 48 h. Early stabilization of digesters was achieved by adding 20 or 50MM FeSO4 though the latter concentration was faster. When 20MM FeSO4 was added to the daily-fed cow dung and poultry litter waste digesters, it increased methanogenesis by 40% and 42%, respectively, and increased the turnover rate of total solids, volatile solids and volatile fatty acids and the number of methanogens.