An experimental study on the use of a sequencing-batch membrane bioreactor (SBMBR) for the treatment of mixed municipal wastewater

Abstract

Several water treatment techniques have been combined using the sequencing batch reactor with the membrane bioreactor for addressing water pollution. However, cleaning of the membrane is dependent on the approach involved as well as the operating conditions. In the present study, the sequencing-batch membrane bioreactor was used to treat real mixed municipal wastewater. The pollutant removal and membrane filtration performances were examined. The results show that the average removal rates of chemical oxygen demand (COD), total nitrogen, NH3-N, total phosphorus, and turbidity were 90.75, 63.52, 92.85, 87.58, and 99.48%, respectively, when the system was in continuous operation for 95 days. The membrane had a significant effect on COD and turbidity removal and provided stable performances for nitrogen and phosphorus removal. By observing the appearance of the membrane modules before and after the cleaning operation, it was concluded that the deposited sludge and granular sediment on the membrane surface can be effectively removed by hydraulic cleaning. In addition, recovery of membrane filtration performance to 60% of that of a new membrane can be achieved. Furthermore, we found that different sequences and duration of cleaning have different effects on the recovery of membrane filtration performance. HIGHLIGHTS Sequencing-batch membrane bioreactor (SMBR) was used to treat municipal wastewater.; We examined pollutant removal and membrane filtration performances over 95 days.; Removal rates of COD, TN, NH3-N, TP, and turbidity varied from 63.52 to 99.48%.; Recovery of membrane filtration performance to 60% was possible by hydraulic cleaning.; Recovery increases to 97.6% if alkaline and acid washes follow hydraulic cleaning.;

Keywords

• membrane cleaning
• membrane fouling
• mixed municipal wastewater
• nitrogen and phosphorus removal
• sequencing-batch membrane bioreactor