Cavitation-based pretreatment strategies to enhance biogas production in a small-scale agricultural biogas plant

Biogas production from lignocellulosic biomass e.g. animal manures and agricultural residues may play a fundamental role as renewable energy sources. Many pretreatment methods can be used to prepare these substrates for biogas production. In this study, hydrodynamic cavitation and ultrasound were used for agricultural residues pretreatment to enhance its biomethanization. A small-scale study allowed to assess biogas productivity and energy efficiency for agricultural biogas plant (ABP) with/without cavitation-based pretreatment of cattle manure and wheat straw. Hydrodynamic cavitation pretreatment (HCP) and ultrasonic pretreatment (UP) significantly enhanced biogas production to 430 and 460 L methane/kg volatile solids (VS). respectively. The final net energy output of ABP/ABP-UP/ABP-HCP was respectively 56/52/61 kWh/d (p < 0.05). Our study showed, that hydrodynamic cavitation could be an efficient technique for agricultural residues pretreatment. (C) 2019 International Energy Initiative. Published by Elsevier Inc. All rights reserved.