摘要
目前,刻画场地重非水相液体(dense non-aqueous phase liquid,DNAPL)污染常用的钻孔取样和井间分溶示踪试验方法成本高昂。相比而言,单井注抽试验节省经费,且对污染源区的扰动少,但该试验方法推估DNAPL残留量的准确性尚未得到定量验证。针对该问题,基于数值方法分析了示踪剂类型、注抽速率、污染源区结构等因素对单井注抽试验推估DNAPL残留量精度的影响。结果表明:(1)选用分溶系数比2,2-二甲基-3-戊醇(2,2-dimethyl-3-pentanol,DMP)低的己醇进行示踪,示踪剂回收更加充分,推估污染物残留量的平均精度增幅可达35.11%;(2)当注入速率从100 m^(3)/d提高至130 m^(3)/d、抽出速率从120 m^(3)/d提高至150 m^(3)/d,示踪剂接触的污染源区面积更大,均质源区对应的污染物残留量平均精度从42.45%提高到60.26%,非均质源区对应的平均精度从27.69%提高至48.72%;(3)污染源区结构复杂程度的增加会阻碍示踪剂的运移,非均质源区对应的平均精度比均质源区降低了13.15%;(4)单井注抽示踪试验更适用于离散状为主的污染源区,其平均精度比池状为主的源区增加了15.74%。单井注抽试验结合数值分析可有效推估残留非水相液体的分布,建议在DNAPL污染场地精细调查中使用,可为场地风险评估和修复方案的制定提供参考。
The drilling methods and the partitioning inter-well tracer tests which are often used to characterize dense non-aqueous phase liquids(DNAPL)source zones cost a lot.Compared with common methods,the single-well“push-pull”partitioning tracer tests not only save money,but also reduce the disturbance to the contaminated site,which can be used to estimate the residual DNAPL.However,the accuracy of this method in estimating residue DNAPL has not been quantitatively verified.To solve the problem,this paper analyses the influence of several factors on estimating the accuracy of residual DNAPL based on the numerical method,including tracer type,the injection and pumping rate and contaminant source zone architectures.The results display that Hexanol with a smaller partition coefficient than DMP can be selected for tests,as the tracer are recovered more fully,which can result in the average accuracy of residue DNAPL estimated to increase by 35.11%.When the injection rate of the tests increases from 100 m^(3)/d to 130 m^(3)/d and the pumping rate increases from 120 m^(3)/d to 150 m^(3)/d,the tracer can expose to a larger contaminant source area so that the average accuracy of the homogeneous source zones increases from 42.45%to 60.26%while the average accuracy of the heterogeneous source zones increases from 27.69%to 48.72%.The increase of the complexity of the source zone architectures will hinder the tracer migration,and the average accuracy of the heterogeneous source zones is 13.15%lower than that of the homogeneous source zones.The single well“push-pull”partitioning tracer test is more suitable for the ganglia-dominated contaminant source zones,and the average accuracy of the ganglia-dominated contaminant source zones is 15.74%higher than that of the pool-dominated source zones.The single-well“push-pull”partitioning tracer tests combined with numerical analysis can effectively estimate the distribution of residual NAPL,and are recommended for use in the fine investigation of DNAPL contaminated sites,so as to
作者
顾瑞婷
施小清
郭琼泽
宋美钰
徐红霞
吴吉春
GU Ruiting;SHI Xiaoqing;GUO Qiongze;SONG Meiyu;XU Hongxia;WU Jichun(Key Laboratory of Surficial Geochemistry,Ministry of Education/School of Earth Sciences and Engineering,Nanjing University,Nanjing,Jiangsu 210023,China)
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2023年第4期204-212,共9页
Hydrogeology & Engineering Geology
基金
国家自然科学基金项目(41977157)。
关键词
重非水相液体
单井注抽示踪试验
穿透曲线
UTCHEM
污染源区
DNAPL
single-well“push-pull”partitioning tracer test
breakthrough curves
UTCHEM
contaminant source zone
