Heavy metal removal from contaminated sludge for land application: A review
Heavy metal removal from contaminated sludge for land application: A review
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DOI：
10.1016/j.wasman.2005.09.017
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发表时间：
2006-01-01
期刊：
影响因子：
8.1
通讯作者：
Dacera, Dominica del Mundo
中科院分区：
文献类型：
--
作者：
Babel, Sandhya;Dacera, Dominica del Mundo
近年来，各种去除污泥中重金属的方法得到了广泛的研究，以尽量减少污泥在土地应用过程中的潜在健康风险。本文对化学萃取法、生物沥滤法、电再生法和超临界流体萃取法在去除污染污泥中重金属方面的应用进行了比较和分析。此外，形态的研究，这可以表明污泥中的不同形式的重金属的易分解性，也提出。实验研究表明，不同提取技术的金属提取效率有很大差异。酸处理似乎可以有效地去除镉，达到高达100%的去除一些研究，相比，生物浸出。SFE的去除率也高于生物淋滤。铬，铅和镍似乎也有效地去除了酸处理。对于Cu、Mn和Zn的去除，生物浸出工艺似乎是合适的，对三种金属的最大去除率分别为91%、93%和96%，对Zn的最小去除率高达64%。SFE工艺对Cu、Mn和Zn的去除也给出了良好的结果。电再生对锰的去除效果较好，但仍不如酸处理和生物浸出工艺。对于化学萃取，由于使用无机酸和络合剂可能产生的不利影响，人们的兴趣更多地指向利用有机酸作为萃取剂，因为它们的生物降解性和在弱酸性条件下去除金属的能力，因此需要较少的酸。生物浸提过程，虽然它似乎给出了一个更高的金属提取的收率与较低的化学品成本比化学提取，可能会受到限制的系统无法科普自然环境条件，需要严格监测的通风速率和温度，并具有适用性，只有低污泥固体浓度。进行全面研究将有助于更好地评估这一进程的效率。电回收技术因其相对较高的能耗和对污泥的适用性有限而受到限制。另一方面，SFE方法受到工艺复杂性和适用于有效金属萃取的配体成本的限制。这两种技术仍处于应用的早期阶段，因此需要进一步的基础和应用研究。最后，几乎所有研究的处理技术的共同优点是，某些金属的提取效率高到足以将污泥中的金属去除到适合土地应用的水平。(c)2005爱思唯尔有限公司保留所有权利。
In recent years, various methods for heavy metal removal from sewage sludge have been extensively studied in order to minimize the prospective health risks of sludge during land application. In this paper, a comparative review and critical analysis of the application of chemical extraction, bioleaching, electroreclamation, and supercritical fluid extraction (SFE), in removing heavy metals from contaminated sludges is presented. Moreover, speciation studies, which can indicate ease of leachability of the different forms of heavy metals in sludge, are also presented. Experimental studies revealed a broad range in metal extraction efficiencies of the different extraction technologies. Acid treatment seemed to effectively remove Cd, attaining as much as 100% removal for some studies, as compared to bioleaching. SFE also gave higher removal efficiency than bioleaching. Cr, Pb and Ni seemed to be also effectively removed by the acid treatment. For the removal of Cu, Mn and Zn, the bioleaching process seemed to be appropriate with maximum removal efficiencies of 91%, 93% and 96% for the three metals, respectively, and as high as 64% minimum removal efficiency for Zn. The SFE process also gave good results for Cu, Mn and Zn removal. Electroreclamation exhibited better removal efficiency for Mn, but is still inferior to acid treatment and bioleaching processes. For chemical extraction, because of the adverse impacts that can result from the use of inorganic acids and complexing agents, interest can be directed more toward utilizing organic acids as extracting agents because of their biodegradability and capability to remove metals at mildly acidic condition, hence requiring less acid. The bioleaching process, although it seems to give a higher yield of metal extraction with lower chemical cost than chemical extraction, may be limited by the inability of the system to cope with the natural environmental conditions, requires strict monitoring of aeration rate and temperature and has applicability to only low sludge solids concentration. A full-scale study would be useful to better assess the efficiency of the process. The electroreclamation technology is limited by its relatively higher energy consumption and limited applicability to sludge. The SFE method, on the other hand, is limited by the complexity of the process and the cost of ligands suitable for effective metal extraction. Both of these technologies are still in their early stage of application and hence there is a need for further basic and applied studies. Finally, the common advantage for almost all treatment technologies studied is that the extraction efficiencies for some metals are high enough to remove metals from sludge to levels suitable for land application. (c) 2005 Elsevier Ltd. All rights reserved.