超滤膜集成工艺处理滦河水的中试研究

发布时间：2018-06-01 22:01

本文选题：浸没式超滤膜 + 预处理技术　；参考：《西安建筑科技大学》2013年博士论文

【摘要】：近年来随着水环境的逐渐恶化，饮用水标准的逐渐提高，净水厂常规处理工艺的局限性越发凸显，传统处理工艺的升级改造势在必行。目前，超滤膜技术作为第三代城市净水技术的核心技术，受到越来越广泛的关注。本研究结合天津市杨柳青水厂处理工艺的升级改造，以浸没式超滤膜为基础，利用中试系统，对超滤膜集成工艺进行了深入研究，主要研究成果和结论如下: (1)膜出水浊度与混凝剂的种类和投加量无关。采用不同混凝剂预处理后的膜出水浊度均在0.075NTU左右，不同强化混凝技术对膜出水有机物的去除效能及对膜污染的控制效能有一定的相似性，均为PACl最优，FeCl_3其次，AS最差。PACl对不同特性有机物的预处理效能优于FeCl_3和AS，尤其在去除亲水性和小分子量有机物方面更具有优势。采用正交试验与加权评分法相结合的方法，综合考虑膜系统出水水质、△TMP及产水率三方面因素，得出膜系统最佳运行参数为：膜通量18L/m~2·h，过滤周期90min，5周期排空一次，反洗流量3.6m~3/h，反洗时间60s，气冲流量3.2m~3/h。 (2)采用投影寻踪聚类分析法对杨柳青水厂水源水进行了水质分期，将源水划为了三个水质期：低温期（12月～次年3月）；高藻期（6月～9月）；正常期（4月～5月，10月～11月）。不同水质期源水中溶解性有机物以强疏水性有机物和亲水性有机物为主，其中又以分子量＜500Da的有机物所占比例最高。考察膜集成系统对不同水质期水中污染物的去除效能得出，各水质期膜出水浊度均能保持在0.1NTU以下，颗粒物均小于10个/mL，对原水CODMn的去除率在45%左右，对UV254和DOC的去除率均在25%左右，对水中的细菌和藻类物质几乎可以全部去除；研究还发现系统对原水疏水性有机物和大分子量有机物具有较好的去除效能，而对亲水性有机物和小分子量有机物去除效能较差。 (3)低温期水中溶气析出是影响膜系统稳定运行的主要因素，采用控制初始和上限TMP的运行方式虽然可在短期实现膜系统的稳定运行，但是会增加系统运行的成本和难度，影响运行的连续性，而采用气水分离和自控组合技术，可有效实现水中气泡的收集和排出，避免其对膜系统稳定运行的影响。高藻期经预氯化后会使混凝出水中疏水性有机物和小分子量有机物含量增多，不仅降低了系统对有机物的去除效率而且加剧了膜污染；采用生物操控预处理技术，可以有效降低原水中藻类的含量，出水藻类计数平均为2773万个/L，比未采用生物操控技术时降低了约42.9%，并可在确保膜出水水质的前提下，降低藻类对膜系统的影响，实现膜系统的稳定运行。 (4)以受污染超滤膜为研究对象，考察了不同水质期EFM的清洗方式为：正常期和低温期以柠檬酸清洗为主，间歇采用次氯酸钠清洗，高藻期则采用相反的清洗方式。对低温期和高藻期受污染膜表面进行SEM和能谱仪分析，得出不同水质期造成膜污染的物质元素基本一致，区别在于低温期膜污染主要为无机物污染，而高藻期为有机物污染；采用原子吸收分光光度法和GC/MS分析法对化学清洗洗脱液进行成分分析后，认为膜表面的无机物污染主要是由Fe盐在膜表面的沉积造成的，而有机污染物主要为小分子量不饱和疏水性芳香族化合物。 (5)采用实际工程与中试相结合的方式，对比常规工艺、压力式膜工艺、浸没式膜工艺的除污效能和经济性，对污染物的去除效能压力式膜工艺略优于浸没式膜工艺，，但相差不大，均优于常规工艺，其中对浊度和耗氧量的去除率约比常规工艺提高了4%和6%，膜出水余铁均＜0.05mg/L；一次性产水率均高于85%；运行成本常规工艺较低，分别比压入式膜工艺和浸没式膜工艺节省了32.2%和21.6%.采用构建层次分析模型的方法，从不同工艺的“成本”和“效益”两方面着手，对不同工艺进行综合评价，得到常规工艺、压入式膜工艺和浸没式膜工艺的重要性权重为（0.2518,0.3318,0.4164），按权重越大越优原则，得出浸没式膜工艺相对于其他两种工艺更适合于杨柳青水厂的生产运行。
[Abstract]:In recent years, with the gradual deterioration of the water environment and the gradual improvement of the standard of drinking water, the limitation of the conventional treatment process of the water purification plant is becoming more and more prominent, and the upgrading and upgrading of the traditional processing technology is imperative. At present, the ultrafiltration membrane technology is becoming more and more widely concerned as the core technology of the third generation of urban water purification technology. This research combines with Tianjin Yang. The upgrading of the processing technology of Liu Qing water plant is based on the submerged ultrafiltration membrane, and the integrated process of the ultrafiltration membrane is studied by using the pilot system. The main research results and conclusions are as follows:
(1) the turbidity of the membrane effluent has nothing to do with the type and dosage of coagulant. The turbidity of the membrane effluent with different coagulants is around 0.075NTU. The removal efficiency of the organic matter in the membrane effluent and the control efficiency of the membrane fouling are similar to that of the different coagulants, all of which are PACl best, FeCl_3 is second, and the worst.PACl of AS is different to different special features. The pretreatment efficiency of sexual organic matter is better than that of FeCl_3 and AS, especially in the removal of hydrophilicity and small molecular weight organic matter. The optimum operating parameters of membrane system: membrane flux 18L/m~2. H are obtained by combining the orthogonal test with the weighted scoring method, considering the water quality of the membrane system, Delta TMP and the water yield of three factors. The filtration period is 90min, the 5 cycle is emptied once, the backwash flow is 3.6m~3/h, the backwash time is 60s, and the air flow rate is 3.2m~3/h.
(2) using the projection pursuit cluster analysis method, the water quality of Yangliuqing water plant was divided into three stages: low temperature period (December to March), high algae period (June to September), normal period (April May, October to). The dissolved organic matter in the source water of different water quality period was strongly hydrophobic organic and hydrophilic organic The ratio of the organic matter with molecular weight < 500Da is the highest, and the removal efficiency of the membrane integrated system to the water pollutants in different water quality periods is investigated. The turbidity of the effluent is kept below 0.1NTU, the particles are less than 10 /mL, the removal rate of the original water CODMn is about 45%, and the removal rate of UV254 and DOC are all in the water. About 25%, the bacteria and algae in the water can be removed almost completely. The study also found that the system has a better removal efficiency for hydrophobic organic matter and macromolecular weight organic matter in the original water, but the efficiency of the removal of hydrophilic organic and small molecular weight organic matter is poor.
(3) the dissolution of gas in water at low temperature is the main factor affecting the stable operation of the membrane system. Using the operation mode controlling the initial and upper limit TMP can realize the stable operation of the membrane system in the short term, but it will increase the cost and difficulty of the system operation and influence the continuity of the operation, and the combination of gas and water separation and self-control combination can be effectively realized. The collection and discharge of bubbles in water can avoid the effect on the stable operation of the membrane system. The prechlorination of high algae will increase the content of hydrophobic organic matter and small molecular weight organic matter in the coagulant water after prechlorination, which not only reduces the removal efficiency of the organic matter but also aggravates the membrane fouling. The biological manipulation pretreatment technology can effectively reduce the removal efficiency of the organic matter. The algae content in low raw water is 27 million 730 thousand /L, which is about 42.9% lower than that without biological manipulation technology, and can reduce the influence of algae to the membrane system and realize the stable operation of the membrane system on the premise of ensuring the water quality of the membrane.
(4) taking the polluted ultrafiltration membrane as the research object, the cleaning methods of EFM in different water quality period were investigated: the normal period and the low temperature period were mainly citric acid cleaning, the sodium hypochlorite cleaning was used intermittently and the opposite cleaning method was used in the high algae period. The analysis of the surface surface of the polluted membrane in the low temperature and the high algae period was analyzed by the energy spectrum analyzer, and the different water quality period was obtained. The material elements of membrane fouling are basically the same, the difference is that the membrane pollution is mainly inorganic pollution in the low temperature period, and the high algae stage is organic pollution. After the analysis of the chemical cleaning eluate by atomic absorption spectrophotometry and GC/MS analysis, it is believed that the inorganic pollution of the membrane surface is mainly made by the deposition of Fe salt on the surface of the membrane. Organic pollutants are mainly small molecular weight unsaturated hydrophobic aromatic compounds.
(5) by combining the practical engineering with the pilot test, the removal efficiency and economy of the conventional process, the pressure membrane process and the submerged membrane process are compared. The pressure membrane technology for the removal efficiency of the pollutants is slightly better than the submerged membrane technology, but the difference is much better than that of the conventional process. The removal rate of turbidity and oxygen consumption is much higher than that of the conventional one. The technology improved 4% and 6%, the effluent of the membrane was all less than 0.05mg/L; the one-time water production rate was higher than 85%; the operation cost was lower than the conventional process. 32.2% and the submerged membrane process were saved respectively than the pressure entry membrane process and the submerged membrane process, and the method of constructing the analytic hierarchy model was adopted, from the "cost" and "benefit" two aspects of different processes. The process is synthetically evaluated and the conventional process is obtained. The importance weight of the pressure entry membrane process and the submerged membrane process is (0.2518,0.3318,0.4164). According to the principle of greater and greater weight, it is concluded that the submerged membrane technology is more suitable for the operation of Yangliuqing water plant compared with the other two processes.
【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU991.2

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