Effect of nitrate concentration on performance of pre-denitrification moving bed biofilm reactor system in treating coal gasification wastewater

Abstract

Abstract An anoxic moving bed biofilm reactor (ANMBBR) followed by an aerobic moving bed biofilm reactor (AEMBBR) operated as pre-denitrification system was used to investigate the effect of different influent NO3 −-N concentrations on performance of the pre-denitrification system in treating real coal gasification wastewater. Influent NO3 −-N concentration was controlled at 50, 100, 200, and 400 mg/L during the experiments. Evolution of COD and phenols in the effluent of the ANMBBR and AEMBBR, and performance of nitrification in the AEMBBR with different influent NO3 −-N concentrations were studied. Almost complete denitrification was achieved when influent NO3 −-N concentration was 100 mg/L. NO3 −-N and NO2 −-N accumulated in the effluent of the ANMBBR with influent NO3 −-N concentrations of 200 and 400 mg/L. NO3 −-N concentration of 400 mg/L facilitated high NH4 +-N removal efficiency in the AEMBBR when influent NH4 +-N concentration was around 165 mg/L. The ratio of CODconsumed/NO3 −-Nconsumed along w...