Biochemical methane potential of pumpkin energy crops co-digested with swine wastewater

Abstract

Anaerobic co-digestion (ACoD) of livestock waste with energy crops (EC) can increase methane yield and the profitability of biodigesters. The biochemical methane potential (BMP) of two commercial pumpkin species, “Paulista” (Cucurbita moschata) and “Moranga” (C. maxima), was evaluated in a laboratory setting. These pumpkins were either crushed or cooked and mixed with swine wastewater (SWW). The treatments included: AMonoD of SWW (T0) and ACoD of SWW + raw Paulista (T1), cooked Paulista (T2), raw Moranga (T3), and cooked Moranga (T4). The volume and composition of biogas were measured, and the modified Gompertz, Cone, modified First Order, and Logistic models were adjusted. T3 recorded the highest specific productions (1.39 m3 biogas and 0.91 m3 CH4 kg-1 VS), surpassing (p ≤ 0.05) the AMonoD and the other trials, without altering the methane content in biogas. It is concluded that crushed raw moranga is a low-cost EC that can significantly enhance the performance of ACoD with SWW, opening up exciting possibilities for the future of biogas technology. The integration of BMP with cone modelling provides reliable parameters for sizing more compact and economically attractive rural biodigesters.