垃圾填埋场区域氨氮污染地下水的修复方案比选

Comparison and Selection of the Remedial Schemes for Ammonia Nitrogen-Contaminated Groundwater in Landfill Sites

早期建设的简易生活垃圾填埋场的防渗措施不足,易发生渗漏,造成填埋场周围地下水的氨氮浓度升高。文章针对华中地区某垃圾填埋场区域氨氮污染地下水,提出抽取处理加异位生物修复、空气注入加原位生物修复两种修复方案,并采用AHP-TOPSIS(层次分析法-逼近理想排序)方法进行方案的比选。在建立合适的比选指标体系基础上,采用AHP-TOPSIS方法进行综合比选研究。结果表明,空气注入+原位生物修复技术更适合于该区域地下水的修复。TOPSIS方法由于缺乏确定评价指标权重的过程,在层次多元分析中的应用受到限制,而AHP是多层次多因素权重确定的有效工具,将二者结合起来,先由AHP确定指标权重,再运用TOPSIS对备选地下水修复方案进行排序,从而弥补了二者各自的不足。AHP-TOPSIS方法可作为环境工作者进行场地修复方案比选的有效工具。

Due to the insufficient countermeasures against leakage, the substandard-discharged leachates from the early simply-constructed landfills caused elevated ammonia nitrogen concentration in the surrounding groundwater. In this study, with regard to the ammonia nitrogen contaminated groundwater in a landfill site located in the Central China, two schemes of pumping and treatment plus ex-situ bioremediation and air sparging plus in-situ bioremediation were proposed. AHP-TOPSIS（analytical hierarchy process-technique for order preference by similarity to ideal solution） methodology was used for a comprehensive screening of the remedial schemes on the basis of establishment of a suitable evaluation indicator system. The analytic result indicated that air sparging in combination with in-situ bioremediation was more suitable. Theoretically, TOPSIS lacked the procedures of ascertaining the evaluating index weights, resulting in the restriction in hierarchical multivariate analysis, while AHP was an effective tool for determination of the multi-level and multi-factor weights. Therefore, AHP was firstly used for ascertaining the index weights and then TOPSIS was adopted to rank the candidate remediation schemes so as to mutually make up their own defects. As a result, AHPTOPSIS could be used as an effective tool for the environmentalists to select the best site remediation plans.