基于好氧颗粒污泥的膜生物反应器处理离子型稀土冶炼废水

Treatment of ionic rare earth smelting wastewater by a membrane bioreactor based on aerobic granular sludge

稀土冶炼有机废水是一种危害性大、水质复杂的高浓度酸性废水,主要污染物包括有机物、氨氮、悬浮物、无机盐、重金属等。因此研究如何有效处理稀土冶炼有机废水对水体、土壤的保护具有重大意义。本研究搭建了序批式膜生物反应器(SBR-MBR),并结合好氧颗粒污泥(Aerobic Granular Sludge,AGS)组成好氧颗粒污泥膜生物反应器(AGS-MBR)。在此基础上,研究了不同碳氮比(有机物中碳与氮的总含量的比值C/N)对AGS-MBR处理工艺的影响。结果表明,在C/N=10时,好氧颗粒污泥稳定性最好,对COD、NH_(4)^(+)-N、TN和TP的脱除率稳定后可达99.0%、96.7%、79.3%、91.1%;进水C/N的降低对AGS-MBR去除COD的影响较小,对出水N的形态和TP影响较大,并且当C/N≤7时,部分好氧颗粒污泥发生解体,出水TN和TP浓度达到《城镇污水处理厂污染物排放标准》GB 18918—2002(2006)一级A排放标准要求,为进一步探讨研究更低C/N的稀土冶炼有机废水的处理工艺提供理论依据。

Organic wastewater from rare earth smelting is a high-concentration acid with great harmfulness and complex water quality.The main pollutants include organic matter,ammonia nitrogen,suspended matter,inorganic salts,and heavy metals,so it is of great significance to study how to effectively treat organic wastewater from rare earth smelting to protect water and soil.A sequential batch membrane bioreactor(SBR-MBR)was constructed,combining with aerobic granular sludge(AGS)to form an aerobic granular sludge membrane bioreactor(AGS-MBR).On this basis,the effect of different C/N ratios(the ratio of total contents of carbon to nitrogen in organic matter C/N)on the AGS-MBR treatment process was studied.The results show that when C/N is 10,the aerobic granular sludge has the best stability,with the removal rates of COD,NH_(4)^(+)-N,TN and TP at 99.0%,96.7%,79.3%and 91.1%,respectively.The decrease in influent C/N has little influence on the removal of COD by AGS-MBR but has a great effect on the form of effluent N and TP.When C/N≤7,part of the aerobic granular sludge disintegrates,and the effluent TN and TP concentrations meet the requirements of Grade A discharge standard GB 18918—2002(2006)in the Pollutant Discharge Standard for Urban Sewage Treatment Plants,which provides a theoretical basis for further research on the treatment of organic wastewater from rare earth smelting with lower C/N ratios.