Treatment of aquaculture farm effluent containing antibiotics in high-rate membrane bioreactor

High-rate membrane bioreactor (MBR) was applied for simultaneous removal of organic substances, nitrogen and antibiotics, i.e., amoxicillin (AMX), sulfadiazine (SDZ) and trimethoprim (TMP) in aquaculture farm effluent. The operation of MBR was carried out under different conditions, i.e., (1) no sludge wastage, (2) periodical sludge wastage to control sludge concentration at 5 g L-1 and (3) addition of sponge media (10% v/v) as hydraulic retention time was kept constant at 4 h. While high biochemical oxygen demand, total Kjeldahl nitrogen and NH3 removal of 85% or more were consistently achieved under all operating conditions, there was a large variation in antibiotic removal among the studied antibiotics ranging from >99% for AMX to 36% for SDZ. Biomass control in the MBR through sludge withdrawal did not have adverse impact on AMX and TMP removal as they were mainly removed through biodegradation but reduced the removal of recalcitrant compound, i.e., SDZ, by 10%. Moreover, membrane filtration could also help retaining residual antibiotics within the MBR.