污泥调理中添加剂对污泥脱水性能及粘滞特性的影响研究

发布时间：2018-03-15 10:24

本文选题：污泥　切入点：脱水性能　出处：《浙江大学》2017年硕士论文　论文类型：学位论文

【摘要】：改革开放三十年来,我国经济发展迅速,随着工业化进程加快,污水排放量日益增长。经污水处理产生的剩余污泥中含有大量致病菌、重金属等有害物质,未经合理的处理处置,容易对土壤、水体、大气等造成污染,对人类健康和环境安全造成巨大威胁。污水处理厂产生的剩余污泥含水率过高,无法满足污泥处置的要求,因此在对污泥进行处置之前,需对剩余污泥进行机械脱水,甚至热干化,使污泥含水率降到一个较低水平。由于污泥的粘滞特性,在污泥的脱水过程中,容易发生粘壁和结团现象,从而增加机器的运行负荷,使能耗升高,效率降低,同时也容易带来一定的安全隐患。本文研究了化学调理中添加剂对污泥脱水性能和粘滞特性的影响,选取了三种常用调理剂,分别为无机小分子凝聚剂三氯化铁,无机高分子凝聚剂聚合三氯化铁和有机高分子絮凝剂聚丙烯酰胺。在脱水性能实验中,从离心污泥含水率、上清液zeta电位和污泥絮体粒度三个方面研究了添加剂的影响;粘滞特性实验中,设计了一种可用来测量污泥粘结力和粘附力的实验装置,并对添加了不同浓度凝聚剂和絮凝剂的污泥进行粘结力和粘附力测试,以研究添加剂对污泥粘滞特性的影响。结果表明,无机凝聚剂用于污泥调理时用量大于有机高分子絮凝剂,对污泥絮体颗粒的表面电荷有明显的中和作用,本实验中采用的聚丙烯酰胺为非离子型有机高分子絮凝剂,因此对污泥絮体颗粒表面电荷影响较小,但随絮凝剂添加量的增加,能有效增大絮体颗粒粒径,促进污泥絮凝。在脱水实验中,离心污泥含水率受到调理剂的影响,经过无机阳离子凝聚剂调理的污泥在zeta电位绝对值较低时含水率较低,经过有机高分子絮凝剂调理的污泥含水率随添加量的升高先降低后升高,由此可分别确定无机阳离子凝聚剂和有机高分子絮凝剂的最优添加量。在粘滞特性测试实验中,无机阳离子凝聚剂和有机高分子絮凝剂均对污泥粘滞特性有较大影响,粘附力随凝聚剂和絮凝剂添加量的升高而降低,粘结力则随凝聚剂和絮凝剂添加量的升高先降低后升高,为降低污泥的粘结力和粘附力,可选择最优添加量。经与脱水实验对比可知,提高污泥脱水性能的最优添加量与降低污泥粘滞力的最优添加量相似,合理选择凝聚剂和絮凝剂的添加量可在提高污泥脱水性能的同时降低污泥粘滞力。
[Abstract]:During the past 30 years of reform and opening up, China's economy has developed rapidly. With the acceleration of the industrialization process, sewage discharge is increasing day by day. The excess sludge produced by sewage treatment contains a large number of pathogenic bacteria, heavy metals and other harmful substances. It is easy to pollute the soil, water and atmosphere without reasonable treatment, and to pose a great threat to human health and environmental safety. The water content of excess sludge produced by sewage treatment plants is too high to meet the requirements of sludge disposal. Therefore, before the sludge is disposed of, it is necessary to dewatering the surplus sludge mechanically or even by heat drying, so that the moisture content of the sludge can be reduced to a lower level. Because of the viscosity of the sludge, in the process of sludge dewatering, The phenomenon of wall adhesion and agglomeration is easy to occur, which increases the running load of the machine, increases the energy consumption and reduces the efficiency. In this paper, the effects of additives on sludge dewatering and viscosity characteristics were studied, and three kinds of common conditioners, inorganic small molecule coagulant ferric chloride, were selected. Inorganic polymer coagulant polyferric chloride and organic polymer flocculant polyacrylamide. In the experiment of dehydration performance, the effects of additives on water content of centrifugal sludge, zeta potential of supernatant and particle size of sludge floc were studied. In the experiment of viscosity characteristic, an experimental device was designed to measure the adhesion and adhesion of sludge, and the adhesion and adhesion of sludge with different concentration of coagulant and flocculant were tested. The effect of additives on sludge viscosity was studied. The results showed that the amount of inorganic coagulant used in sludge conditioning was larger than that of organic polymer flocculant, and the surface charge of sludge floc particles was neutralized obviously. The polyacrylamide used in this experiment is a non-ionic organic polymer flocculant, so it has little effect on the surface charge of sludge flocs, but with the increase of the amount of flocculant, the particle size of flocs can be increased effectively. In the dehydration experiment, the moisture content of centrifugal sludge was affected by the conditioner, and the sludge treated by inorganic cationic coagulant had lower water content when the absolute value of zeta potential was low. The water content of sludge treated with organic macromolecule flocculant decreased first and then increased with the increase of the added amount, so the optimum addition amount of inorganic cationic coagulant and organic high molecular flocculant could be determined respectively. Both inorganic cationic coagulant and organic macromolecule flocculant have great influence on sludge viscosity. The adhesion force decreases with the increase of coagulant and flocculant content, and then increases with the increase of coagulant and flocculant content. In order to reduce the adhesion and adhesion of sludge, the optimal addition amount can be selected. By comparing with the experiment of dewatering, it can be seen that the optimal addition quantity of increasing sludge dewatering performance is similar to that of reducing sludge viscosity. Reasonable selection of coagulant and flocculant can improve sludge dewatering performance and reduce sludge viscosity.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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