污染场地多相抽提低碳修复布井方案优化模拟研究

Optimization of Low-Carbon Multi-Phase Extraction Remediation Well Locations in Contaminated Sites by Simulation

多相抽提(multi-phase extraction,MPE)技术常用于土壤与地下水修复,高效、低碳和低成本的布井方案优化是多相抽提技术进一步发展的关键.本研究通过自主编写的MATLAB-TMVOC联合优化程序,以模拟的苯污染场地为研究对象,对抽提井群水平布设方案和抽提井开筛位置进行优化,并探究了土壤渗透率对抽提井布设方案的影响.结果表明:MATLAB-TMVOC联合优化程序具有快速高效的特点,可以免除复杂的人工调参过程,相比人工优化可节省50%以上的模拟时间和90%以上的模拟量.优化后的抽提井布设间距随着土壤渗透率的降低而缩小,对于本研究所构建的模型,当土壤渗透率处在2×10^(-13)~8×10^(-12)m^(2)范围内时,土壤渗透率每减少10^(-13)m^(2),优化后的抽提井间距会减小约0.13 m,即土壤渗透率减少一个数量级,抽提井间距应减小17.8%~48.3%.对于土壤渗透率低于10-13m2的黏性地层,污染羽核心位置的布井间距应当小于4 m.优化后的修复方案能够降低成本、减少碳排放,当目标去除率为90%时,优化后的MPE修复方案可以节约29.7%~34.7%的运行成本、22.7%~29.3%的总成本以及21.4%~40.4%的碳排放量.研究显示,污染场地MPE修复井布设方案应当与场地渗透率和污染羽分布相结合,采取在污染源至污染羽尾方向上由密至疏的非均匀布井方案,以实现高效低碳修复.

Multi-phase extraction(MPE)technology is commonly used for soil and groundwater remediation.Optimizing well locations for efficient,low-carbon and cost-effective remediation is crucial to the further development of MPE technology.In this study,a selfdeveloped MATLAB-TMVOC joint optimization program was used to optimize the horizontal location and screen opening position of the extraction wells in a simulated benzene-contaminated site.The influence of soil permeability on the layout plan of extraction wells was also investigated.The results showed that the MATLAB-TMVOC joint optimization program exhibited rapid and efficient characteristics.It eliminated the complex manual parameter adjustment process,saved more than 50% of simulation time and reduced more than 90% of simulation compared to manual optimization.The optimized spacing between extraction wells decreased with decreasing soil permeability.For the model constructed in this study,when the soil permeability was within the range of 2×10^(-13) m^(2) to 8×10^(-12) m^(2),a decrease of 10^(-13) m^(2) in soil permeability led to a reduction of 0.13 m in the optimized spacing between extraction wells.With a decrease of one order of magnitude in soil permeability,the spacing between extraction wells should be reduced by 17.8% to 48.3%.For cohesive formations with soil permeability below 10^(-13) m^(2),the spacing between wells in the core area of the pollution plume should be less than 4 m.The optimized remediation plan can reduce costs and carbon emissions.When the target removal rate is set at 90%,the optimized MPE remediation plan can save 29.7% to 34.7% of operational costs,22.7%to 29.3% of total costs,and 21.4% to 40.4% of carbon emissions.The study revealed that the arrangement of MPE remediation wells in contaminated sites should be combined with site permeability and pollution plume distribution,and a non-uniform well layout plan from dense to sparse in the direction from the pollution source to the tail of the pollution plume in order to achieve effective and low-carbon remediation.