Synergetic effect of combined pretreatment for energy efficient biogas generation

Abstract

Physiochemical disintegration of waste activated biosolids (WAB) through thermochemical (TC) pretreatment requires high energy and cost for efficient energy generation. Therefore in the present study, an attempt has been made to enhance the biodegrdability and to minimize the operational cost of TC pretreatment by combining it with ozonation. A higher solubilization of about 30.4% was achieved at lesser energy input of about 141.02kJ/kgTS and a ozone dosage of about 0.0012mgO₃/mgSS through this combined thermo chemo ozone (TCO₃) pretreatment. The methane production potential (0.32gCOD/gCOD) of TCO₃ pretreatment was comparatively higher than the (0.19gCOD/gCOD) TC pretreatment. The energetic analysis and economic assessment of the proposed method of pretreatment can possibly reduces the energy requirement of TC pretreatment with a positive net profit of about 35.49$/ton of biosolids.

Keywords: Biopolymers; Chemical oxygen demand solubilization; Suspended solids reduction; Thermo chemo ozone pretreatment; Waste activated biosolids.