Effect of PAC dosage in a pilot-scale PAC–MBR treating micro-polluted surface water

To address the water scarcity issue and advance the traditional drinking water treatment technique, a powdered activated carbon-amended membrane bioreactor (PAC–MBR) is proposed for micro-polluted surface water treatment. A pilot-scale study was carried out by initially dosing different amounts of PAC into the MBR. Comparative results showed that 2 g/L performed the best among 0, 1, 2 and 3 g/L PAC–MBR regarding organic matter and ammonia removal as well as membrane flux sustainability. 1 g/L PAC–MBR exhibited a marginal improvement in pollutant removal compared to the non-PAC system. The accumulation of organic matter in the bulk mixture of 3 g/L PAC–MBR led to poorer organic removal and severer membrane fouling. Molecular weight distribution of the bulk liquid in 2 g/L PAC–MBR revealed the synergistic effects of PAC adsorption/biodegradation and membrane rejection on organic matter removal. Additionally, a lower amount of soluble extracellular polymer substances in the bulk can be secured in 21 days operation.