Keywords: anaerobic digestion, cattail degradation, rumen cultures, kinetic modelling, hydrolysis
Anaerobic batch degradation of cattail by rumen cultures
The anaerobic batch digestion of cattail with two substrate concentrations of 10 g and 30 g Volatile Solids (VS)/l was investigated in this study. The hydrolysis of cattail was not significantly affected by the substrate concentrations, and it was able to be described by a first-order kinetic model with hydrolysis constants of 0.298 d−1 and 0.294 d−1, respectively. The main aqueous products from cattail degradation were Volatile Fatty Acids (VFA), in which acetate, propionate and butyrate were dominant. The molar ratio of acetate to propionate (3.3) at 10 g VS/l was larger than that (2.3) at 30 g VS/l, when the acidogenesis phase was at the stationary period. The lag period of the methanogenic phase at 10 g VS/l was shorter than that at 30 g VS/l. A modified Gompertz equation could be adopted to describe the kinetics of products formation.