【作者】 赵清华；

【导师】 冯素萍；

【作者基本信息】 山东大学 ， 环境科学， 2008， 硕士

【摘要】 随着城市污水量的不断增加,污水处理过程中产生的污泥量也在不断增加。污泥中不仅含有丰富的营养元素,也含有难降解的金属有毒物质,如果处理不当则会造成更严重的二次污染,同时有毒重金属也是限制污泥农用或污泥制砖等综合利用的主要障碍,因此对城市污水处理过程中产生的污泥进行研究,掌握重金属元素在污水处理过程中的迁入途径及迁移转化规律对污泥的处置及综合利用具有重要的意义。本文以微波消解技术及电感耦合等离子体发射光谱法(ICP-AES)为基础,以济南市水质净化一厂进水泵房、初沉池、曝气池、二沉池、脱水机房等各处理单元水样及污泥为研究对象,采用BCR连续提取法进行金属形态(酸溶态、可还原态、可氧化态)的提取,以ICP-AES法测定了样品中的Cd、Cr、Cu、Mn、Mo、Ni、Pb、Zn等8种重金属元素的含量,研究了重金属元素在污水处理过程中各个单元水相及污泥中的分布规律及形态分布,并采用相应的数学方法进行数据处理,找出重金属在污水处理过程中形态分布特性,以此为城市污水处理厂污水处理过程中所产污泥中重金属污染的防治和污泥的合理化处置及资源化利用提供基础数据。研究表明:(1)济南市水质净化一厂处理后的污水中重金属元素Cd、Cr、Cu、Pb、Mo、Zn、Ni、Mn含量符合污水处理厂污染物排放标准GB18918-2002中的要求,同时重金属元素Cd、Cr、Cu、Zn含量符合农用灌溉水质标准GB5084-92的要求。(2)在污水处理过程中,污水中的重金属元素Cd、Cu、Mn、Mo、Pb大部分在初沉池可得到沉淀,部分在活性污泥处理阶段被活性污泥所吸附。重金属元素Cd、Cr、Cu、Zn在初沉池污泥中的含量高于剩余污泥中的重金属含量,而金属元素Cr、Ni、Zn则相反,在剩余污泥中的含量高于初沉污泥中的含量。(3)污水处理过程中重金属元素在污泥中的沉积没有显著的差异,同一金属元素在不同泥样中的形态优势均有所不同,可采用对污水处理过程作适当的改进或控制酸度,在不同处理阶段将不同重金属除去。(4)采用BCR连续提取法研究重金属形态分布规律为:元素Cd、Zn、Pb形态主要为可还原态,元素Mn主要为酸溶态,其可氧化态所占百分比较低(9.3—11.8%);元素Cr、Cu、Mo主要存在形态为可氧化态,其酸溶态所占百分比相对较低(＜1.2%);元素Ni在酸溶态、可还原态、可氧化态三态中所占比例差别不大。更多还原

【Abstract】 As the amount of city sewage disposal increases,the quantity of sludge,a side product from the process,is on a rapid rise.Sludge not only contains abundant nutritive elements,but also heavy metals,which are non-degradable toxic substances.If not handled properly,further pollution may occur.The presence of heavy metals prevents sludge from being used for agricultural purpose or brick manufacturing.Therefore it is quite necessary to monitor sludge produced from urban sewage treatment and the transfer and distribution of metals in the treatment process.By means of microwave digestion sample pre-treatment technology and inductively coupled plasma atomic emission spectrometry(ICP-AES),we studied the water sample and sludge from the treatment unit of Jinan City Water Purification Plant.ICP-AES was applied in determining the content of eight kinds of heavy metals:Cd,Cr,Cu,Mn,Mo, Ni,Pb,and Zn.Thereby we are able to gather information on aqueous phase and distribution of metals in each treatment unit,as well as their intake and transformation in the sewage plant.The application of BCR method facilitated the research on the states (acid-soluble state,reductive state,and oxidizable state)of heavy metals in primary sludge,aeration pool sludge,double precipitation sludge,dewatering room.With data processing based on mathematical methods,we discover the characteristics of the heavy metals in various states.Those data can be used for the purpose of heavy metal control, urban sludge disposal and utilization.The research suggested:(1)the content of Cd,Cr,Cu,Pb,Mo,Zn,Ni,and Mn from the discharge of the plant complied with GB18918-2002 pollutant discharge requirements on sewage treatment plant,and Cd,Cr,Cu,the Zn content meets GB5084-92 standards on agricultural irrigation water.(2)At the sewage treatment plant,most metallic elements (Cd,Cu,Mn,Mo and Pb)precipitated in the primary pool,while a portion was absorbed by activated sludge.The content of those elements in the primary sludge is higher than that in the excess sludge.In contrast,the content of Cr,Ni and Zn in the excess sludge is higher than that in the primary sludge.(3)In the sewage treatment process the metallic element that deposits to the sludge does not change much.The morphological advantage of the same metallic element varies with different sludge samples,which can be modified in the treatment process.(4)With BCR method,we gained insight into the distribution pattern of the metallic elements:Cd,Zn,Pb mainly exist in deductive state,while Pb doesn’t have acid-soluble state.Mn mainly exists in acid soluble state,whose content in oxidization state is rather low(9.3—11.8%).Cr,Cu and Mo are mainly in the oxidable state,whose content in acid soluble state is relatively low(＜1.2%).The content of Ni varies slightly with each state.更多还原