An investigation of the enhancement of biogas yields from lignocellulosic material using two pretreatment methods: Microwave irradiation and steam explosion

Abstract

Two pretreatment methods, microwave irradiation and steam explosion, were investigated in this work. The aim of the study was to investigate whether these methods would improve the biodegradability of wheat straw as a lignocellulosic feedstock. Microwave pretreatment was carried out on milled straw with an irradiation time of 15 minutes, at a temperature of either 200 or 300 °C in the oven. The steam explosion pretreatment was carried out on milled straw at 210 °C for 10 minutes. To determine the methane production potential, anaerobic digestion batch trials were run under mesophilic conditions for 60 days. The methane yields of the microwave-pretreated straw decreased by 65% for an attained temperature of 200 °C and by 92% for 300 °C. After steam explosion pretreatment, however, the methane yields of the straw increased by approximately 20% when compared to untreated straw samples. These results indicate that microwaving does not optimize methane production from wheat straw, while steam explosion yields positive results.