RESUMO
Anaerobic digestion was investigated as a potential method for on-farm disposal of fallen stock (pig carcases), degrading the carcase material to produce biogas and digestate. The effects of feedstock (sugar beet pulp or pig carcase material or a 50:50 mix) and organic loading rate (50â¯g-TS L-1 or 100â¯g-TS L-1), during mesophilic (35⯰C) anaerobic digestion were investigated. Anaerobic digestion was achieved for all experimental treatments, however the pig carcase material at the higher organic loading rate produced the second highest methane yield (0.56â¯Nm3 kg-VS-1 versus a range of 0.14-0.58â¯Nm3 kg-VS-1 for other treatments), with the highest percentage of methane in total biogas (61.6% versus a range of 36.1-55.2% for all other treatments). Satisfactory pathogen reduction is a legislative requirement for disposal of carcase material. Pathogens were quantified throughout the anaerobic digestion process. Enterococcus faecalis concentrations decreased to negligible levels (2.8 log10 CFU g-TS-1), whilst Clostridium perfringens levels remained unaffected by treatment throughout the digestion process (5.3⯱â¯0.2 log10 CFU g-TS-1).