Impacts of Psychrophilic Conditions on Anaerobic Membrane Bioreactors Treating Municipal Wastewater

Abstract

Three 5 L AnMBRs that incorporated submerged ZeeWeed® hollow fibre PVDF membranes with a nominal pore size of 0.04 µm and a nominal membrane surface area of 0.047 m2 were employed. The AnMBRs were operated at a solids retention time (SRT) of 30 days and a hydraulic retention time (HRT) of 0.4 days. At the start of the study, the AnMBRs were inoculated with primary digester effluent obtained from the Galt Wastewater Treatment Plant. After inoculation, the daily feed into the AnMBRs was pumped out of a wet well receiving municipal sewage from a City of Waterloo sanitary sewer line at the University of Waterloo.

Throughout the study, a daily volume of 10.13 L of wastewater was fed to each AnMBR, 0.130L of Waste Sludge was manually wasted, and 10 L of permeate was generated. The AnMBRs were operated in a relaxed mode with 8 minutes of permeation followed by 2 minutes of relaxation and were operated at a constant flux while Transmembrane Pressure (TMP) was monitored. Gas sparging was provided to the AnMBRs to reduce membrane fouling. This study was conducted in three phases. During the initial phase of operation, the AnMBRs were operated at 24°C, 15°C and 10°C respectively. TCOD, SCOD, TSS, VSS, VFA, biogas production, pH and TMP were regularly monitored to characterize the physical and biological performance of the AnMBRs.