Enzymatic pre-hydrolysis of organic fraction of municipal solid waste to enhance anaerobic digestion

Abstract

Enzymatic pretreatment was proposed to enhance the anaerobic digestion of Organic Fraction of Municipal Solid Waste (OFMSW). Enzyme cocktails were produced at laboratory scale from Aspergillus niger fermentation on wheat bran (WB) and OFMSW. The effect of enzyme load, reaction time and agitation speed on OFMSW hydrolysis was determined. Results showed that enzymatic hydrolysis of OFMSW improved organic matter solubilisation. Indeed, pretreatment of OFMSW using WB and OFMSW cocktails resulted respectively in 37.1 and 34.6% change of the soluble chemical oxygen demand and 50 and 40.6% change of the reducing sugars.Anaerobic digestion tests showed that enzyme-treated OFMSW yielded higher biomethane production than raw OFMSW. After hydrolysis by WB and OFMSW cocktails, methane potential of OFMSW increased from 189.2 mL gVS−1 to around 607 and 672 mL gVS−1, respectively. The result confirmed that the use of enzyme cocktails derived from raw waste bioconversion could be a valuable approach to improve biomethane potential of organic wastes.