Pretreatment Impact on Biomethanation of Lignocellulosic Waste

Lignocelluloses are often a major or sometimes the sole components of different waste streams from various industries, forestry, agriculture and municipalities. Hydrolysis of these materials is the first step for either digestion to biogas (methane) or fermentation to ethanol. However, enzymatic hydrolysis of lignocelluloses with no pre-treatment is usually not so effective because of high stability of the materials to enzymatic or bacterial attacks. Pre-treatment helps to improve the process of hydrolysis. In this work different methods of pre-treatment were studied. The present work illustrates the effect of acid, alkaline pre-treatment on different sizes of wheat straw and anaerobic digestion of treated biomass for the production of biogas in batch stirred tank bioreactor under particular parameters. The quality and quantity of biogas produced was analysed by gas chromatography and water displacement methods respectively. The Untreated wheat straw gave a biogas yield of 104 ml/g and methane content of 64%. Acid treated wheat straw gave biogas yield of 130, 140 and 134 ml/g and methane content of 68%, 72%, 75% for 1%, 2%, 5% acid concentration respectively. Similarly, for alkali treatment gave biogas yield of 124, 128, 126ml/g and methane content of 66%, 69%, 71% for 1%, 2%, 5% NaOH concentration respectively.