膜生物反应器用于微污染地表水处理的中试研究

引言 地表水作为主要的饮用水源水,其日益严重的污染问题给传统的水处理工艺带来巨大挑战.将膜生物反应器(MBR)应用于微污染水处理,进行饮用水制备是解决上述问题的一项新技术1].向MBR内投加粉末活性炭(PAC)所形成的MBR-PAC组合工艺集物理吸附、生物净化和膜分离于一体,具有良好的污染物去除能力.目前,将MBR作为微污染水处理主体工艺的研究并不多见.香港大学的李晓岩等2]研究证实MBR组合工艺处理微污染水效果良好.清华大学的莫罹等3]也进行了类似的研究.但均限于小试试验,并且对相应的膜污染问题关注不多.

Treatment of polluted surface water by MBR process for drinking water production

In China surface water pollution has made quality drinking water production difficult. The major pollutants in surface water are organic matter measured by COD_ Mn and ammonia nitrogen. To remove these pollutants effectively, membrane bioreactor (MBR) was studied as a substitute for the conventional water treatment process. Powdered activated carbon (PAC) was dosed into the reactor to enhance the treatment efficiency. A pilot scale MBR was operated continuously for 130 days. In this period, 79.1% of COD_ Mn , 85.9% of UV_ 254 , 97.9% of UV_ 410 , 99.6% of turbidity and 97.4% of NH_3-N could be removed, and the total coli-group was not detectable per 100 ml in the treated water. Concerning the accumulation of refractory organics in the reactor, an index A_ m (organics accumulative factor in the mixed liquor) was proposed. It helps to evaluate the efficiency of biodegradation and PAC adsorption of organic pollutants in the reactor. Moreover,A_m appeared to have a negative effect on the removal efficiency of organic pollutants.At the end of the pilot test, three-step cleanings were carried out for the fouled membrane. The flux recovery for each cleaning step was measured, and the composition of the eluted foulants after each chemical cleaning step was analyzed. The results demonstrated that organic pollutants were the major membrane-fouling substances, and chemical cleaning with 0.4% sodium hypochlorite could remove them efficiently.