High concentration powdered activated carbon-membrane bioreactor (PAC-MBR) for slightly polluted surface water treatment at low temperature

In this study, different concentrations of PAC combined with MBR were carried out to treat slightly polluted surface water (SPSW) at low temperature (10 °C). Effects of PAC on the efficiencies of operation, treatment, and the performance of the process were investigated. It was found that the effluent quality, performance efficiency, resistance of shock load were all enhanced and chemical irreversible membrane fouling was reduced with increasing dosage of PAC in MBR. Only when the concentration of PAC which acted as biological carriers was high enough (i.g., 50 g/L), nitrification without initial inoculation in the filtration tank could start within 19 days and be completed within 35 days at 10 °C. Fifty grams per liter PAC was the optimal dosage in MBR for stable and extended operation. Under this condition, mean removal efficiencies of ammonia nitrogen (NH3-N), dissolved organic carbon (DOC) and UV254 were 93%, 75%, and 85%, respectively.

► Effluent quality and performance efficiency were enhanced with increase PAC dose into MBR.
► Ammonia nitrogen oxidation without initially inoculation occurred as soon as possible only when PAC was enough.
► Fifty grams per liter PAC was the optimization dosage in MBR for stable and extended operation.
► Better resistance of shock load and less irreversible membrane fouling in 50 g/L PAC-MBR.
► Excellent effluent quality and performance efficiency in 50 g/L PAC-MBR.