Assessing biomass activities, sludge characteristics and membrane fouling in the University of Cape Town membrane bioreactor under ferric chloride addition

Membrane bioreactor (MBR) technology has been commonly employed in the treatment of domestic wastewater. However, total phosphorus (TP) removal performance and membrane fouling are two major challenges for MBR application. In this study, FeCl 3⋅ 6H2O was added to the membrane tank (MT) to improve the overall performance of University of Cape Town (UCT)-MBR. When the Fe(III) dosing concentration was increased from 0 to 1.8 mmol/L, the concentration of TP in the effluents was declined from 3.0 to 0.1 mg/L, and the high transmembrane pressure was reduced by 21.9%. The total nitrogen (TN) removal efficiency remained similar. However, when the Fe(III) dosing concentration was increased to 2.2 and 2.6 mmol/L, the phosphorus accumulating organisms (PAOs) and ammonia oxidizing bacteria (AOB) activities were greatly inhibited. Based on the overall nutrient removal and membrane fouling mitigation performances, the optimal Fe(III) dosing concentration was determined to be 1.8 mmol/L [Display omitted]