Influence of hydraulic retention time and temperature on the performance of an anaerobic ammonium oxidation fluidized bed membrane bioreactor for low-strength ammonia wastewater treatment

Abstract The feasibility of anaerobic ammonium oxidation (Anammox) process with a fluidized bed membrane bioreactor (Anammox-FMBR) was evaluated for 561 days treating synthetic wastewater containing 35 mg/L of NO2--N and 25 mg/L of NH4+-N. During start-up periods, higher nitrogen loading rate (NLR) induced faster stabilization than the low NLR. Total nitrogen (TN) removal efficiency was over 82% even with short hydraulic retention time (HRT) of 0.75 h at 25 oC conditions, but decreased to below 30% at 15 oC. Pronounced effect of operating temperature at lower range was supported by high activation energy (Ea) value. The membrane fouling was controlled well as evidenced from negligible fouling rates when the systems were operated at less than 13 L/m2/h flux with granular activated carbon (GAC) fluidization as cleaning media. With the estimated low energy requirements of 0.0005 kWh/kg Nremoved, the Anammox-FMBR could be successfully applied in mainstream operation for the energy efficient treatment of low ammonia wastewater.