Treatment of Short-chain Nonylphenol Polyethoxylates by the Technique of Combing Biological Contact Oxidation with an Anoxic/oxic Membrane Bioreactor

摘要

The technique of combing biological contact oxidation with an anoxic/oxic membrane bioreactor was designed for the treatment of short-chain nonylphenol polyethoxylates (SC-NPnEO, n<3). The temperature (T), dissolved oxygen (DO) and hydraulic retention time (HRT) were selected as influence factors by an orthogonal experiment of three factors and three levels. Degradation effect of NPEO 0~5 and other components were selected as the evaluation index for the orthogonal experiment, evaluating the influence degree of each parameter to the degradation of the target pollutant, and determining the optimum condition of the system operation. The results showed that the removal rate of COD and NH4+-N was stable at more than 85%, and the average removal rate of NPEO0~5 was remained above 98%. The optimum operation parameters of the system were achieved as temperature of 33℃, DO of 5mg/L, HRT of 24h. The largest influence factor to the degradation of total NPEO0~5 was DO, followed by temperature and HRT. These results showed the technique of combing biological contact oxidation with an anoxic/oxic membrane bioreactor had good sludge retention capacity and shock load resistance capacity and efficient degradation of SC-NPnEO and water pollutants, has broad application prospects.