垃圾填埋场区域地下水铅的修复方案比选:以拉萨市为例

拉萨市垃圾填埋场随着使用年限的增长,填埋场区域地下水中重金属铅的含量偏高。为了更好地保护地下水,采用物理屏蔽法、抽出处理法和原位修复法作为修复方案。运用AHP-TOPSIS方法来选取最佳修复方案:先通过AHP层次分析法确定权重,选取了建设条件、经济条件、技术条件、环境条件、污染物特征、水化学特征6个指标体系来建立层次分析模型;然后采用TOPSIS接近理想目标的排序方法对修复方案的选取进行优劣排序分析。结果表明:2种方法综合分析得到的权重值由大到小的顺序为原位修复法、物理屏蔽法、抽出处理法,最后确定原位修复技术更加适合于该场区地下水修复。

COMPARISON AND SELECTION OF REHABILITATION SCHEMES FOR GROUNDWATER LEAD IN LANDFILL AREA: A CASE STUDY OF LHASA

The content of lead in groundwater of Lhasa landfill was increased with the improvement of its service life. In order to protect groundwater, physical shielding method, extraction treatment method and in-situ remediation method were used as the candidate remediation schemes. The AHP-TOPSIS method was used to select the best restoration scheme. Firstly, the weights for all factors were determined by analytic hierarchy process (AHP). The AHP model was established by selecting six indexes systems: construction conditions, economic conditions, technical conditions, environmental conditions, pollutant characteristics and hydrochemical characteristics. Then, the ranking method of TOPSIS close to the ideal goal was used to analyze the selection of final repair schemes. The results showed that the weight values obtained by the two methods were in the order of in-situ remediation, physical shielding and extraction. Finally, it was determined that in-situ remediation technology was the most suitable scheme for groundwater remediation in the site.