陶瓷膜及其集成工艺处理微污染饮用水的研究

发布时间：2019-06-06 06:13

【摘要】：超滤膜过滤工艺在饮用水处理中的应用日益广泛，目前使用的多为有机膜。但对于微污染饮用水，处理工艺需要预氧化，而氧化剂容易导致有机膜老化损坏。陶瓷膜具有耐氧化、机械强度高等特点，在微污染饮用水处理中受到关注。本论文针对臭氧/陶瓷膜工艺，研究了系列孔径陶瓷膜的过滤性能，臭氧氧化对污染物去除效果和膜通量的影响，分析了臭氧对陶瓷膜污染的控制效能和机理。针对季节性污染的原水，提出了新型集成式的臭氧/陶瓷膜-生物活性炭(BAC)工艺。利用小试实验系统对集成工艺处理微污染原水的性能进行了评估，通过规模为120m3/d的中试系统对集成工艺进行了验证。 系列陶瓷膜孔径包括5、10、50、100和200nm，，陶瓷膜对颗粒物的去除率高于96%。膜出水中颗粒物含量随陶瓷膜孔径减小而降低。臭氧投加量低于3mg/L对膜出水颗粒数的影响不明显，投加量为3~5mg/L时，陶瓷膜初滤水中2~3μm颗粒物数量有所增加。综合考虑跨膜压差及膜通量，本论文推荐采用孔径为50至100nm陶瓷膜。陶瓷膜直接过滤对CODMn的去除率为15%~45%，UV254的去除率低于10%。臭氧/陶瓷膜组合可显著改善UV254的去除，臭氧投加量高于3mg/L时改善了CODMn的去除率。膜孔径减小或原水浊度升高有利于陶瓷膜对有机物的去除。 臭氧能够减缓陶瓷膜的污染，臭氧与有机物在原水和膜孔内的直接反应改变了有机物的结构和性质，降低了膜的污染负荷。有机物是膜污染的主要贡献因素，对可逆和不可逆膜污染组分分析表明，有机物亲/疏水组分对陶瓷膜的污染能力为亲水性（HPI）疏水性（HPO）弱疏水性（TPI）。分子量为400、1100、1500、和3180Da的小分子有机物在膜不可逆污染中起着重要作用。 臭氧/陶瓷膜-BAC工艺可去除50%~55%的总有机碳和UV254。臭氧氧化降低了有机物分子量并提高了其生物可降解性，BAC通过吸附和生物降解作用去除有机物和氨氮。工艺出水浊度低于0.14NTU，2μm颗粒数小于60个/mL，出水氨氮浓度低于0.5mg/L。臭氧/陶瓷膜强化了BAC中的优势功能细菌，控制了致病菌和藻类的繁殖，保障BAC有效运行。投加臭氧的曝气过程提高了DO浓度，促进了Nitrosomonas和Nitrospira等功能菌的生长，改善了氨氮的去除效果。本论文提出的集成工艺对于传统自来水厂升级改造以应对微污染原水和保证饮用水安全具有重要的意义。
[Abstract]:The application of ultrafiltration membrane filtration process in drinking water treatment is becoming more and more extensive, and most of them are organic membranes at present. However, for micro-polluted drinking water, the treatment process needs pre-oxidation, and oxidant is easy to lead to aging and damage of organic film. Ceramic membrane has been paid more and more attention in the treatment of micro-polluted drinking water because of its oxidation resistance and high mechanical strength. In this paper, the filtration performance of a series of pore size ceramic membranes, the effect of ozone oxidation on pollutant removal and membrane flux were studied, and the control efficiency and mechanism of ozone on ceramic membrane fouling were analyzed. A new integrated ozone / ceramic membrane-biological activated carbon (BAC) process was proposed for seasonal pollution of raw water. The performance of the integrated process for the treatment of micro-polluted raw water was evaluated by using the small-scale experimental system, and the integrated process was verified by the pilot system with the scale of 120m3/d. The pore size of a series of ceramic membranes includes 5, 10, 50, 100 and 200 nm, and the removal rate of particles by ceramic membranes is more than 96%. The content of particulate matter in the effluent decreased with the decrease of the pore size of ceramic membrane. When the dosage of ozone was lower than that of 3mg/L, the effect of ozone dosage on the number of particles in the effluent of ceramic membrane was not obvious. When the dosage of ozone was 3~5mg/L, the amount of particles in the initial filtration water of ceramic membrane increased. Considering the pressure difference and flux of transmembrane, the ceramic membrane with pore size of 50 to 100nm is recommended in this paper. The removal rate of CODMn by direct filtration of ceramic membrane is 15% 鈮

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