Pilot-scale Study on Enhancing Nitrogen and Phosphorus Removal with MBBR

In order to solve the problem of low efficiency in nitrogen and phosphorus removal and poor operation stability of Jining WWTP,a field pilot-scale test for enhancing nitrogen and phosphorus removal with MBBR was carried out to investigate the effects of HRTs,ratios of suspended carriers,external carbon source on the nitrogen removal capacity.The results show that under the conditions of room temperature(21 to 29 ℃),8.4 h HRT,100% sludge return ratio,300% aerobic mixed liquid return ratio,50% ratio of the carriers,the average removal rates of COD,NH+4-N,TN and TP are 80.58%,92.4%,46.3% and 65.5%.The treatment capacity is better than that of the original system.Under the above mentioned conditions,when external carbon source(methanol) of 33 mg/L is added,the removal rate of TN is increased from 46.3% to 72.3%,the effluent TN is less than 10 mg/L,and the effluent COD is decreased to some extent.The MBBR process can improve the nitrification capacity and the resistance to shock loading,which provides reference for reconstruction of WWTP.