Method for recovery of contaminated groundwater through in situ enhanced aeration

Abstract

The present invention relates to a method for recovery of contaminated groundwater through in situ enhanced aeration, which comprises the following steps: digging more than one surfactant injection well, an aeration well and an extraction well in an area with the groundwater contaminated, injecting surfactant into the area with the groundwater contaminated through the surfactant injection well to dissolve the surfactant into the groundwater so as to form surface tension in the area with the groundwater contaminated, starting the extraction pump to pump an aeration zone into negative pressure, and starting the aeration pump for continuous aeration. The method for recovery of contaminated groundwater through in situ enhanced aeration provided by the present invention effectively solves the problem that the majority of pollutants can be removed only after flowing into the porous channel through diffusion due to the narrow porous channel near the aeration well, and improves the saturation degree of the air in the groundwater, thereby increasing opportunities of exposure the pollutants to the air. Tests show that, when the aeration rate is 100ml / min, the surface tension is reduced to 50.4dyn / cm from 70.5dyn / cm, the half-life for removal of the pollutant chlorobenzene is reduced to 16min from 31min, and simultaneously the trailing concentration is reduce to 5.1mg / L from 22.08mg / L. The removal rate can be increased to 98.5 percent from 89.2 percent after 420 minutes. The method for recovery of contaminated groundwater through in situ enhanced aeration provided by the present invention has the advantages of simple process, low cost, low surfactant injection and less impact on the environment.

Description

Technical field: [0001] The invention relates to the treatment of groundwater polluted by organic pollutants, in particular to a method for strengthening groundwater aeration and repairing groundwater through surfactants. Background technique: [0002] In recent years, with the rapid development of my country's economy and society, environmental pollution incidents have occurred frequently, especially the high-concentration, highly toxic organic pollutants and high-intensity site pollution caused by major environmental pollution incidents such as explosions, leaks, and illegal discharges. pose a serious threat. [0003] Groundwater aeration technology (air sparging, AS) is considered to be the most effective method for removing VOCs from saturated soil and groundwater. By injecting fresh air into the aquifer, due to the effect of buoyancy, air-borne pollutants gradually rise and are collected by gas-phase extraction wells in the vadose zone, thereby achieving the purpose of ...

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Problems solved by technology

[0004] However, through laboratory and field research, it is found that the existing AS technology still has some disadvantages: the air flow is only limited in a few narrow channels near the aeration well, and most pollutants can only be removed by diffusion into the channels first. , Therefore, the diffusion effect greatly limits the removal efficiency of pollutants [Document 1: Ji W, Dahmani A, Ahlfeld D P, et al.1993.Laboratory study of air sparging: air flowvisualization.Ground Water Monit R, 13(4): 115-126], resulting in slow pollutant removal and high tailing concentration

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