城镇污水处理厂污泥中重金属含量及化学形态研究

发布时间：2018-01-01 19:40

本文关键词：城镇污水处理厂污泥中重金属含量及化学形态研究　出处：《成都理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来随着城市污水处理厂建设不断增加及污水处理率迅速提高,市政污泥也就大量产生,随之污泥的处理处置及环境影响问题得到越来越多的关注。市政污泥的综合利用能够使其得到科学、妥善的处置,并完全可以作为资源再次为我们所利用,同时可以带来一定的经济价值。在城市污水处理厂污泥的综合利用中,通常不仅研究污泥中重金属含量也研究重金属的形态,这将有利于根据重金属的存在形态选择合适的处理方法和合理的工艺。本文选取四川省29座污水处理厂为重点研究对象,涵盖四川省内县级市55座污水处理厂,重点研究每座污水处理厂不同污水处理工艺下污泥中重金属含量及化学形态分布,主要研究结果如下:)1.四川省不同污水处理厂的污泥样品中As、Cd、Cr、Hg、Pb、Ni、Cu、Zn等八种重金属元素的总量差异显著,同一种重金属元素在不同污水处理厂的污泥中含量变化范围也较大。2.四川省城镇污水处理厂污泥中As、Cd、Cr、Hg、Pb、Ni、Cu、Zn等八种重金属元素含量不高,存在个别污泥中Cu和Zn超标的情况。3.四川省城镇污水处理厂污泥中重金属元素形态研究结果表明:Hg、Cr、As和Pb元素主要以残渣态存在,Cd元素主要以残渣态、强有机结合态和铁锰氧化物结合态形式存在,Ni元素主要以水溶态及残渣态形态存在,Zn元素主要以水溶态和离子交换态形式形态分布;Cu元素主要以残渣态、强有机结合态和铁锰氧化物结合态形式存在。4.四川省城镇生活污水处理厂污泥中含有大量有机质和氮、磷、钾等植物营养成分,而且四川省各地区污水处理厂污泥重金属农用利用风险普遍又较低,有利于进行农业资源化利用。5.对污泥重金属的农用利用风险评价结果表明四川省各地区污水处理厂污泥农用风险普遍较低,可以进行农用。个别污水处理厂污泥的Zn和Cu重金属含量较高农用生态风险性较高,不推荐直接施用,应采取措施进行减量化无害化处理后再进行农用方面的利用。为了研究市政污泥中重金属形态这一问题,本文采用了连续多级提取法测定污泥样品中的As、Cd、Cr、Hg、Pb、Ni、Cu、Zn等八种重金属元素的形态,并对与污泥营养成分相关的N、P、K和有机质等物质的含量进行了测定。通过综合污染指数法和潜在生态危害指数两种农业风险评价方法对污泥的重金属污染状况进行了综合评价。另外,本文还研究四川省城市污泥的实用处置的方法,为污泥的实用处置提供一些新的思路。因此,通过本文的研究探索了城镇污泥中重金属的总量和形态分布规律,同时积累了污泥的基本理化数据,为拟定相应污泥无害化处理和资源化利用工艺技术方案提供数据理论依据。
[Abstract]:In recent years, with the increasing construction of municipal sewage treatment plant and the rapid improvement of sewage treatment rate, municipal sludge will be produced in large quantities. As a result, more and more attention has been paid to the treatment and disposal of sludge and the environmental impact. The comprehensive utilization of municipal sludge can make it scientific and properly disposed, and can be used as a resource for us to use again. At the same time, it can bring some economic value. In the comprehensive utilization of municipal sewage treatment plant sludge, not only the content of heavy metals in sludge is usually studied, but also the forms of heavy metals. This will be conducive to the selection of appropriate treatment methods and reasonable process according to the existing forms of heavy metals. 29 wastewater treatment plants in Sichuan Province are selected as the focus of study in this paper. Covering 55 sewage treatment plants at county level in Sichuan province, the distribution of heavy metals and chemical forms in sludge under different sewage treatment processes in each sewage treatment plant was studied. The main results are as follows: 1. The total contents of eight heavy metals, such as Aspergectadecrhium, PbPbPbPbPbPbCU, Cu-Zn, in sewage sludge samples from different wastewater treatment plants in Sichuan Province are significantly different. The content of the same heavy metal in the sludge of different sewage treatment plants also varies greatly. 2. The content of the same heavy metal elements in the sludge of the municipal sewage treatment plant in Sichuan Province is also large, and the content of the same heavy metal element in the sludge of the sewage treatment plant in Sichuan Province is also large. The content of Zn and other eight heavy metals is not high, and the Cu and Zn in individual sludge exceed the standard. 3. The speciation of heavy metal elements in the sludge of Sichuan municipal wastewater treatment plant is studied. The elements of as and Pb mainly exist in the residual state and the elements of CD exist in the form of residue, and the elements of Ni exist in the form of strong organic bound state and iron-manganese oxide bound state, and mainly exist in the form of water soluble state and residual state state. Zn mainly distributes in the form of water soluble state and ion exchange state. Cu mainly exists in the form of residue, strong organic bound and iron-manganese oxide. There are a lot of organic matter, nitrogen, phosphorus, potassium and other plant nutrients in the sludge of municipal sewage treatment plant in Sichuan province. Moreover, the risk of heavy metal agricultural utilization in sewage treatment plants in Sichuan Province is generally low. The results showed that the agricultural risk of sludge from sewage treatment plants in Sichuan Province was generally low. The heavy metal content of Zn and Cu in the sludge of individual sewage treatment plant is higher than that in agricultural ecological risk, so it is not recommended to apply directly. In order to study the heavy metal speciation in municipal sludge, a continuous multistage extraction method was used to determine as in sludge samples. The speciation of eight heavy metal elements, such as the heavy metal elements, such as the heavy metal elements, such as the heavy metal elements, such as the heavy metal elements, such as the heavy metal elements, such as PbPbPbPbPbNiOCU. The contents of K and organic matter were determined. The heavy metal pollution status of sludge was evaluated by two agricultural risk assessment methods: comprehensive pollution index method and potential ecological hazard index method. This paper also studies the practical disposal methods of municipal sludge in Sichuan province, which provides some new ideas for the practical disposal of sludge. Therefore, the distribution law of the total amount and form of heavy metals in urban sludge is explored through the research in this paper. At the same time, the basic physical and chemical data of sludge were accumulated.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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