Long-term operation of submerged membrane bioreactor for the treatment of high strength acrylonitrile-butadiene-styrene (ABS) wastewater: effect of hydraulic retention time

In this study, the feasibility and the treatment efficiency of treating ABS industrial wastewater by an aerated submerged membrane bioreactor (ASMBR) was investigated. Through a long-term experiment, biomass, biological oxygen demand (BOD5,) chemical oxygen demand (COD), total organic carbon (TOC) and permeate flux were measured to evaluate the MBR performance. The results show that a hydraulic retention time (HRT) of 18 h leads to the highest biomass concentration, a maximum mixed liquor suspended solids (MLSS) value of approximately 35 g/L. Chemical membrane cleaning was employed twice, after 131 and 180 days of operation in the total experimental period of 204 days. The membrane bioreactor led to superior COD and BOD5 removal in ABS wastewater compared to the conventional biological treatment.