地下水曝气修复技术的模型试验研究
Physical modeling of air-sparging technique for groundwater remediation
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摘要: 地下水曝气法是修复土壤和地下水有机污染的有效方法。通过模型试验,探讨了地下水曝气法的工作机理,研究了气体不同类型土体中的运移方式和影响区域。研究表明,最小曝气压力的大小取决于土体毛细压力和静水压力;在孔隙较大的砾石体中,气体以独立气泡的方式运移,单井影响区域基本为抛物型,超过一定曝气压力值后其影响半径不再变化;在孔隙较小的细砂中,气体以稳定的微通道方式运移;当曝气压力相同时,细砂中空气流量小于砾石中的空气流量,但是单井影响范围较砾石体大,脉动曝气效果也较好。Abstract: Air sparging is one of the most efficient techniques to remedy saturated soils and groundwater contaminated with voltaic organic compounds.Based on the model tests,the air flow pattern and the zone of influence(ZOI) were investigated for air sparging process in different types of soil mass.It was shown that the minimum sparging pressure was dependent on the hydro-static pressure and capillary pressure of soil mass;in gravel mass air traveled in bubbles and ZOI was of a parabolic shape;in fine sand mass air flowed in discrete,stable micro-channels and ZOI was larger than those in gravel mass under the same sparging pressure;there was a positive influence of pulsating sparging in sands while it was insignificant in gravels.