Determination of kinetic constants from the co-digestion of dairy cow slurry and municipal food waste at increasing organic loading rates

Abstract

The aim of this study was to investigate the performance and the kinetic constants of anaerobic mesophilic CSTR reactors run at increasing organic loading rates (OLR). The reactors were co-digesting dairy cow slurry (DCS) and municipal food waste (MFW). The supply of DCS was held constant, while the supply of MFW was increased in the four reactors: 0, 14.0, 24.5 and 32.2% (ww). Degradation of organic matter, specific methane yield per mass unit converted organic matter, and the kinetics of the process were used to investigate the performance of the reactors. While the hydraulic retention time was decreased from 25.9 to 17.5 days, the specific methane yield increased from 0.21 to 0.44 l CH4 · gVS−1. The relationship between the kinetic constant and the OLR was found to be linear. The efficiency of the process increased when the OLR increased in this experiment.