Role of hydraulic retention time in enhancing bioenergy generation from petrochemical wastewater

Abstract

The focus of this work was to improve the anaerobic co-digestion yield produced by the optimum hydraulic retention time of petrochemical wastewater and activated manure.Hydraulic retention time appears to be the principal operating parameter, which can affect bacteriological ecology and other features in a reactor operating system. The anaerobic digestion of petrochemical wastewater has been widely studied, and commercial applications have already been recognized. However, the optimization of the hydraulic retention time has not been studied to date.The influence of four hydraulic retention times (12, 9, 6 and 3 days) on biogas and methane generation was investigated. Equal amounts of petrochemical wastewater and activated manure were mixed in a continuously stirred tank reactor. The mixture was run at a mesophilic state (37 °C). At a hydraulic retention time of 9 days, methane generation was 0.99 ± 0.12 LLr−1d−1 with a maximum yield of 0.34 ± 0.02 L g−1 CODremoved−1. The chemical oxygen demand removal efficiency was 98.5 ± 0.5%. The optimum hydraulic retention time (of the three tested values) was determined to be 9 days. The scientific contribution of this anaerobic co-digestion technology with optimized HRT may play a role in degrading the petrochemical wastewater and developing an energy-efficient strategy for waste management.