Anaerobic digestion of acidified slurry fractions derived from different solid–liquid separation methods

Batch assays investigating the ultimate methane yields (B0) of acidified slurry fractions produced with different solid–liquid slurry separation techniques were done. The result showed that the anaerobic digestion (AD) process was inhibited when raw and liquid fractions of sow, pig and dairy cow acidified slurry are digested, but AD treating solid fractions (SF) acidified slurry showed no sulphide inhibition. The B0 of SF acidified sow slurry increased significantly with increasing screen size in the screw press. No significant effect of acidification processes on B0 of SF dairy cow slurry (DCS) was observed. The ultimate methane yields of SF acidified DCS and SF non acidified DCS were 278 ± 13 and 289 ± 1 L kg VS−1, while in term of fresh weigh substrate were 59 ± 2.8 and 59 ± 0.3 L kg substrate−1, respectively.