Study on pollution plume control and removal efficiency of chlorobenzene in groundwater by air sparging

Abstract

Air sparging (AS) has proven to be one of the most effective means of removing volatile organic compounds in groundwater. The effect of air flow rates on air saturation and radius of influence (ROI) was investigated using a two-dimensional laboratory sand tank. The results showed that increased air flow rate led to higher air saturation and larger ROI, however, at high air flow rates, both increases of air saturation and ROI were not significant. The effect of different air flow rates on chlorobenzene migration and removal in sand tank with a certain hydraulic gradient was also studied. When no air injected, the quantity of chlorobenzene flowing out of sand tank with groundwater accounted for 19.7% of the total chlorobenzene introduced to tank after 130h, these proportions were only 3.6% and 0.9% at air injection rates of 0.1, 0.2m3/h respectively. This reveals AS can efficiently reduce contaminant migration. Through effluent gas sample analysis, the volatilized chlorobenzene was 68.2% and 78.6% of the initial chlorobenzene mass after 130h at air injection rates of 0.1, 0.2m3/h respectively. This reveals AS can effectively remove contaminant in groundwater. These two effects are more obvious when higher air flow rate is used.