Effect of thermal treatment of pig manure on methane fermentation

Abstract

 Thermal treatment of pig manure followed by batch and continuous methane fermentation was conducted in order to evaluate its effect on fermentation performance. Up to 200°C of thermal treatment, solubilization of VSS proceeded, but transformation of dissolved TOC with high molecule count into VFA was minimal. The high temperature led to retardation of initial gas generation and low gas generation rate. At 250°C, no gas generation occurred. At 150°C, methane generation per input VS with thermal treatment was 1.2 times greater than that without thermal treatment. The thermal treatment of standard pig manure was disadvantageous to net energy recovery. However, it was estimated that thermal treatment of manure with SS concentration of greater than 2.3 times the SS of standard manure increased net energy recovery over that without thermal treatment.