Performance evaluation of various bioreactors for methane fermentation of pretreated wheat straw with cattle manure

Abstract

This paper examines the performance results of configured semi-continuous mesophilic bioreactors for methane fermentation of pretreated wheat straw co-digested with cattle manure. The semi-continuous process was carried out in three different types of bioreactors, i.e. continuous stirred tank reactor (CSTR), fixed film reactor (FFR), and conventional floating drum reactor (CR), with an organic loading rate of 2.2 kg of volatile solids (VS)/day. The observed results revealed that the configuration of the FFR increased the methane production yield by 41.1%. However, the configuration of the CSTR had only a marginal effect on enhancement of methane production yield (yield increased only by 10.6%) compared to the CR. The VS removal for digesters did not vary much at the same organic loading rate. The study revealed that the pretreated wheat straw with the FFR had yield methane production of 0.342 m3/kg VS, whereas the CSTR and CR had yield methane production of 0.289 m3/kg VS and 0.264 m3/kg VS, respectively.