Effects of high-temperature isochoric pre-treatment on the methane yields of cattle, pig and chicken manure

Abstract

Cattle manure, dewatered pig manure and chicken manure were pre-treated in a high-temperature reactor under isochoric conditions for 15 min at temperatures between 100 and 225 ◦ C with 25 ◦ C intervals to study the effect on their methane yield. After 27 days of batch incubation, cattle manure showed a significant improvement in its biochemical methane potential (BMP) of 13% at 175 ◦ C and 21% at 200 ◦ C. Pig manure showed improvements at temperatures of 125 C and above, with a maximum 29% increase in yield at 200 ◦ C. The BMP of chicken manure was reduced by 18% at 225 C, but at lower temperatures there were no significant changes. It was found that this method of pre-treatment could be feasible if sufficient surplus energy was available or if the energy used in the pre-treatment could be recovered. Keywords: BMP; manure; biogas; thermal; pre-treatment; energy requirements