Anaerobic digestion of paunch in a CSTR for renewable energy production and nutrient mineralization

摘要

A laboratory study investigated the anaerobic digestion of paunch in a continuous stirred tank reactor (CSTR) for the recovery of biogas and mineralization of nutrients. At an organic loading rate (OLR) of 2.8 g VS L~(-1) day~(-1) with a 30-day hydraulic retention time (HRT), a CH_4 yield of 0.213 L g~(-1) VS and CH_4 production rate of 0.600 L L~(-1) day~(-1) were obtained. Post-anaerobic digestion of the effluent from the CSTR for 30 days at 40 ℃ recovered 0.067 Lg~(-1) VS as CH_4, which was 21% of the batch CH_4 potential. Post-digestion of the effluent from the digestate obtained at this OLR is needed to meet the stable effluent criteria. Furthermore, low levels of soluble ions such as K~+, Ca~(2+) and Mg~(2+) were found in the liquid fraction of the digestate and the remainder could have been retained in the solid digestate fraction. This study demonstrates the potential of biogas production from paunch in providing renewable energy. In addition, recovery of plant nutrients in the digestate is important for a sustainable agricultural system.