Municipal Wastewater Treatment Using a UASB Coupled with Cross-Flow Membrane Filtration

A pilot scale up-flow anaerobic sludge blanket (UASB) coupled with cross-flow membrane filtration was used to treat low strength municipal wastewater in Singapore. The application of membrane filtration as a polishing unit of UASB effluent could produce better effluent quantity than conventional UASB. In this research, with gradually reducing hydraulic retention time from 10.0 to 5.5 h, membrane effluent was able to meet the more stringent effluent criterion over the whole experiment. Simultaneously, biogas yield increased from 61.8 to 120.7 mL/g CODremoved, in which methane percentages were also increased from 59.3 to 65.2%, respectively. Furthermore, the results of anaerobic membrane filtration showed that there were three different methods could effectively mitigate rapid membrane fouling and maintain trans-membrane pressure as low and stable as possible. These would reduce membrane cleaning frequency and prolong membrane life span.