污泥中重金属的去除与资源化研究

发布时间：2018-08-13 13:50

【摘要】：随着工业化和城市化进程的加快,人民生活水平的提高,由此引发了一系列环境污染问题。城市污水处理厂的兴建在一定程度上能够缓解生活与工业废水引发的污染问题,而污泥是污水处理厂处理废水的必然产物。污泥中含有大量的N、P、K、有机质和一些微量元素,他们是植物生长所需要的,对植物的生长具有较大的促进作用,然而污泥中也含有一些难于分解的有机物、寄生虫、微生物以及重金属元素等有毒有害物质,若处理不当,将会对环境造成严重的二次污染,同时也会影响污水处理厂的正常运行。因此,需要采取一定的措施对污泥中有毒害物质进行处理。本文通过对污泥的理化性质进行分析,得到污泥中N、P、K等营养元素的含量较高,具有较高的农用价值。同时对污泥中重金属元素的含量及其形态特征进行研究,得出污泥中Cd、Ni的含量已经超过了国家酸性土壤中污泥农用标准,但没有超过国家碱性土壤农用标准,并且污泥中Pb、Cd、Cu、Ni都主要以残渣态形式存在,Pb、Cd、Cu、Ni的残渣态所占比例分别为46.22%、32.5%、39.04%、41.95%。通过地累积指数和潜在生态风险指数数据表明,污泥中重金属具有严重的生态风险。本文还通过利用化学方法、微生物方法、电化学方法分别处理污泥中重金属,分别探讨了不同方法对污泥中重金属的去除效果,以及最佳经济效果。研究结果表明,用化学方法处理时,用硫酸和双氧水混合并调节pH=2时处理效果最佳,此时Pb、Cd、Ni和Cu的去除率分别是68.43%、81.73%、75.51%和86.41%,运行费用大约为5.1元/m3。用微生物淋滤时,投入FeSO4·7H2O和S两种基质的质量都为0.2g时,淋滤的效果较好而且经济适宜,Pb、Cd、Cu、Ni的浸出率分别是74.72%、81.54%、70.46%、77.35%,运行费用大约为2.86元/m3。采用电化学方法处理污泥时,电解污泥电压为35V,电流为80mA,反应时间为6h时,处理效果较好且经济适宜,阳极区中Cu的去除率为57.35%,Pb的去除率为48.42%,Cd的去除率为68.63%,Ni的去除率为49.85%,此时每处理电化学反应器中1m3的污泥所需费用为5.6元。
[Abstract]:With the acceleration of industrialization and urbanization and the improvement of people's living standard, a series of environmental pollution problems have been caused. To some extent, the construction of municipal wastewater treatment plant can alleviate the pollution caused by domestic and industrial wastewater, and sludge is the inevitable product of wastewater treatment in sewage treatment plant. Sludge contains a large amount of Nu Pu K, organic matter and some trace elements, which are necessary for plant growth and have a great promoting effect on plant growth. However, sludge also contains some organic matter, parasites, which are difficult to decompose. Microorganisms and other toxic and harmful substances such as heavy metal elements, if not treated properly, will cause serious secondary pollution to the environment, and will also affect the normal operation of sewage treatment plants. Therefore, some measures should be taken to deal with toxic substances in sludge. Based on the analysis of the physical and chemical properties of sludge, it was found that the content of nutrient elements, such as Nu Pu K, in sludge was higher and had higher agricultural value. At the same time, the contents of heavy metals and their morphological characteristics in sludge were studied. The results showed that the content of CDN and Ni in sludge had exceeded the national agricultural standard of sludge in acidic soil, but it was not higher than the national standard for agricultural use in alkaline soil. In addition, the proportion of the residual state of PbPbCCDCU / Ni in the sludge is 46.222.52 and 39.04 / 41.95respectively in the form of residuals, which are mainly in the form of residuals, and the proportion of them is 46.222.5 and 39.04 respectively, and the proportion of them is 41.95. The data of land accumulation index and potential ecological risk index show that heavy metals in sludge have serious ecological risk. The removal of heavy metals in sludge by chemical method, microbial method and electrochemical method were discussed respectively, and the best economic effect was also discussed. The results showed that the best results were obtained by mixing H _ 2SO _ 4 and H _ 2O _ 2 with pH = 2. The removal rates of Ni and Cu were 68.43% and 86.41%, respectively. The operating cost was about 5.1 yuan / m ~ (3). When biofiltration was used, when the mass of FeSO4 7H2O and S was 0.2g, the leaching efficiency was better and the leaching rate was 74.72cm / m ~ (3), respectively. The operation cost was about 2.86 yuan / m ~ (3), and the leaching rate was 74.72cm ~ 81.54 ~ 70.46g / m ~ (3), and the operation cost was about 2.86 yuan / m ~ (3). When the electrolytic sludge was treated by electrochemical method, the voltage of electrolytic sludge was 35V, the current was 80mAand the reaction time was 6h. The removal rate of Cu in the anode is 57.35 and the removal rate of Pb is 48.42 and the removal rate of CD is 68.63 and the removal rate of Ni is 49.85.The cost of treating 1m3 sludge in electrochemical reactor is 5.6 yuan.
【学位授予单位】：新疆农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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