Anaerobic digestion of solid slaughterhouse waste(SHW)at laboratory scale:Influence of co-digestion with the organic fraction of municipal solid waste(OFMSW)

摘要

Mesophilic anaerobic digestion of slaughterhouse waste(SHW)and its co-digestion with the organic fraction of municipal solid waste(OFMSW)have been evaluated.These processes were carried out in a laboratory plant semi-continuously operated and two set-ups were run.The first set-up,with a hydraulic retention time(HRT)of 25 days and organic loading rate(OLR)of 1.70 kg VS m~(-3)day~(-1)for digestion,and 3.70 kg VS m~(-3)day~(-1)for co-digestion,was not successful.The second set-up was initiated with an HRT of 50 days and an OLR of 0.9 kg VS m~(-3)day~(-1)for digestion and 1.85 kg VS m~(-3)day~(-1)for co-digestion.Under these conditions,once the sludge had been acclimated to a medium with a high fat and ammonia content,it was possible to decrease the HRT while progressively increasing the OLR to the values used in the first set-up until an HRT of 25 days and OLRs of 1.70 and 3.70 kg VS m~(-3)day~(-1),for digestion and co-digestion,respectively(the same conditions of the digesters failures previously).These digesters showed a highly stable performance,volatile fatty acids(VFAs)were not detected and long chain fatty acids(LCFAs)were undetected or only trace levels were measured in the analyzed effluent.Fat removal reached values of up to 83%.Anaerobic digestion was thus found to be a suitable technology for efficiently treating lipid and protein waste.