【作者】 刘晓娟；

【导师】 王海芳；

【作者基本信息】 中北大学 ， 环境工程， 2010， 硕士

【摘要】 医院污水中含有大量细菌、病毒及其他有毒有害物质,如果不加处理直接排入环境水体中,将会对环境和人类健康产生巨大的危害,因此,需要研究对其进行有效处理的方法。随着"SARS"和“甲流”等公共卫生事件的爆发,社会对医院污水处理的关注越来越多。而且,随着对传统医院污水处理方式的缺点的逐渐认识,采用更先进的处理方式是医院污水处理的大势所趋。膜生物反应器(MBR),由于其占地面积小,自动化程度高,出水水质优异,消毒效率好,成为近年来用于废水处理的研究热点。本实验结合MBR和传统活性污泥法中的生物铁法各自的优点,通过在MBR中投加氢氧化铁絮体来改善污泥性能,减缓膜污染,以获得更好的处理效果。对该系统用于医院废水处理的有机物去除效果、污泥特性和膜污染情况进行了研究,在优化工艺的运行条件和参数、污泥浓度以及充分认识微生物特性的基础上对其机理进行了初步探讨,主要的研究结果如下：(1)氢氧化铁投加量为污泥浓度的1.5%的实验条件下,研究在不同曝气时间下有机物的去除效果,得出如下结论：曝气时间7h以后系统对COD、氨氮等的去除趋于稳定,COD浓度可以降低到30mg/L以下,氨氮浓度可以降低到1mg/L以下,在综合考虑经济成本条件下,在之后的实验中选择曝气时间为7h。(2)采用氢氧化铁-膜生物反应器处理医院废水,系统表现出良好的有机物去除效果以及长期的运行稳定性。在连续运行不排泥的条件下,其COD的降解率最高可达到92.1%,氨氮的降解率最高可以达到99.6%,对于有添加剂的医院废水,通过改进工艺条件后出水仍然能达到《医疗机构水污染物排放标准》(GB18466-2005)。(3)生物铁-MBR工艺一定程度上提高了出水水质,本实验条件下,氢氧化铁最佳的投加量为混合液污泥浓度的3%,此时生物铁-MBR出水COD、总P、NH3-N比普通MBR平均分别高9.13%、18%和4.2%。生物铁-MBR中,由于其膜组件对细菌、病毒高效的截留效果,本实验装置对大肠杆菌的去除效率在98%以上。(4)对于生物铁-MBR工艺,氢氧化铁投加量为污泥浓度的1.5%-3%的生物铁污泥具有更好的絮状结构,这样就降低了膜表面滤饼层阻力,缓解了膜孔堵塞对膜污染的影响。然而,当投加量增大到5%时,生物铁污泥解体为碎小的颗粒,就削弱了生物铁污泥对溶解性有机物的吸附,从而,有机物去除率降低。此外,较高的有机物消耗,还会滋生大量的丝状菌,由于丝状菌能释放更多的胞外聚合物,从而加剧了膜的污染,降低了膜通量。(5)研究投加氢氧化铁对跨膜压差(TMP)和膜通量的影响时发现：在投加混凝剂的当天,TMP升高,膜通量突然降低。其原因可能是此时形成的含有铁盐的活性污泥絮体为微絮物,比较碎小,在初期容易形成膜孔的吸附及堵塞阻力Rf。更多还原

【Abstract】 Hospital waste water, which contains a great deal of bacteria, virus and other toxic and harmful components, should be treated and disinfected properly before discharge. Otherwise, it will do great harm to human health and environment. After several public health incidents breaking out, such as the SARS and H1N1,more and more attentions have been attracted on the treatment of hospital sewage. However, it becomes a trend to develop new methods to treat hospital sewage, with the disadvantages of traditional methods being found. Membrane bioreactor(MBR), because of it’s small footprint, high automation, excellent water quality, high disinfection efficiency, become the research focus for wastewater treatment in recent years.This experiment combined MBR with bioferric of conventional activated sludge, which adds hydrogen ferric oxide flocs to MBR to improve the performance of the sludge reduce membrane fouling and obtain better treatment results. This paper makes a research on the organic matter removal rate, sludge characteristic and the membrane fouling of the system. Besides, the mechanism is studied on the analysis of process operating conditions and parameters, sludge concentration, and microbiological characteristics. The following conclusions can be obtained:(1) On the dosage of ferric hydroxide sludge concentration of 1.5%,the removal rate of organic is studied under different aeration time. Following conclusions can be obtained:the removal rate of COD、NH3-N and so on, becomes stabilized after the aeration time of 6h-7h. In the comprehensive consideration of economic costs, the aeration time of 6h-7h is chosen.(2) Under certain conditions, the system of iron hydroxide-MBR showed good organic removal and long-term operation stability for the treatment of hospital wastewater. In continuous operation without sludge discharge condition, the COD degradation rate can reach 92.1%,the degradation rate of ammonia can reach 99.6%.The output water of this improved system can meet the "standards for medical water pollutants"(GB18466-2005).(3)Bioferric-MBR process has improved the quality of effluent to some extent. In this experiments, the iron hydroxide dosage of 3% of MLSS concentration is considered to be the best, on which condition, biological iron-MBR average effluent COD, total P, NH3-N were higher than the ordinary MBR by 9.13%,18%, and 4.2%.In this system, because of the membrane of MBR, the removal efficiency of E. coli is more than 98%.(4) For the biological iron-MBR process, the sludge with hydrogen ferric oxide dosage of 1.5%-3% sludge concentration have good structure, which reduces the membrane surface cake layer resistance and ease membrane pore blockage on the membrane fouling. However, when the dosage was increased to 5% sludge concentration, bio-sludge disintegrates to small particles, which reduce the adsorption ability of biological iron sludge. Thus, the organic matter removal rate is reduced. In addition, the high consumption of organic matter will encourage the growth of filamentous bacteria, which can release much more EPS, thus increasing membrane fouling and reducing membrane flux.(5) On the research of the effect of hydrogen ferric oxide dosage on the TMP and membrane flux, conclusions can got as follows:the first day of adding coagulant, TMP increased and flux suddenly decreased. The reason may be that activated sludge containing ferric floc is too small and adsorbed to the membrane pore to make a blocking resistance Rf.更多还原