Biological treatment of swine waste using anaerobic baffled reactors

Four laboratory-scale anaerobic baffled reactors (with two, three, four, and five chambers, respectively) were used to successfully treat whole swine waste. The baffled reactors did an excellent job of trapping the small diameter, methane-containing particles of proteins, cellulose, hemicellulose, and lipids. Solids retention times of 25, 30, 36, and 42 days were achieved with a corresponding hydraulic retention time of 14 days for two-, three-, four- and five-chamber anaerobic baffled reactors, respectively. COD reductions ranged from 70 to 78% among all the reactors studied. Maximum methane production was observed in the reactors with four and five chambers with a value of 0.59 and 0.62 l/g of volatile solids added at a loading of 4 g VS/l/day, respectively.