The Study Of Air Sparging Using To Remediate The Groundwater Polluted By Chlorobenzene

In recent years, environmental polluted incidents occur frequently along with the rapid development of economic and social. These incidents will bring in high concentrations of toxic volatile organic pollutants especially as explosions and leaks. This is a major threat to people's health and the ecological environment.At present, human's activities have resulted in a wide range of environmental pollution. The emissions, waste water, and the waste residue often directly or indirectly enter the soil and groundwater through air, water and other media during people's living and producing. Once the soil and groundwater are polluted, the impact to the environment is continuous and irreversible. Facing such an unprecedented threat, to protect the soil and groundwater against pollution is receiving a growing concern. Studying the groundwater treatment technologies has become a new hot spot to the environmental engineering sciences and technical studies. Among these methods, air sparging is more and more widely used by its significant advantages such as high reducing efficiency to contaminants and low investment.In this paper, the effect of different impact factors is studied in the course of removing organic pollutants, and make sure the optimum aeration flow is 0.15m3/h under laboratory conditions. Greater the medium particle size is, greater the permeability coefficient is, and better the effect of removing chlorobenzene by air sparging is. When the particle size is smaller, intermittent aeration is suggested to use. When the particle size is larger, the removal efficiency of both two aeration mode is closed, and we suggests to choose continuous aeration in order to shorten the remediation time, It is better to remove chlorobenzene when it is mixed with benzene. This paper studies the effect of air sparging under different aeration on the removal of pollutants, and the impact of groundwater flow to the migration and diffusion of pollutants,and make sure the relative contribution between migration and evapotation on the removal of pollutants.When there is no aeration, the reduction of chlorobenzene concentration is mainly depends on the flow of groundwater, and the chlorobenzene's migration by the flow of groundwater courses the expanding of contaminated area. After the beginning of aeration,the injected air will form air channels. There is gas-liquid mass transfer interfacial area around these channels. Chlorobenzene can enter into air channels through mass transfer zone by diffution and be removed by evapotation. Increasing aeration can inject more air into the area, and generate more air channels and mass transfer area. This strengthens the role of partition and evaporation to chlorobenzene, making the removing rate of chlorobenzene faster.The disturbance generated during the process of injecting air reduces the hydraulic conductivity in the aeration area, and reduces the flow rate of the groundwater. This can increase the pollutant's residence time in the polluted area, reduce the migration caused by groundwater flow, and play a role in the pollutants'interception and control. At the same time, the disturbance role between liquid and gas cut up the chlorobenzene in the medium. In the end, the contaminated area is treated and controlled.During the aeration process, the diffusion and volatilization of the pollutants is the main removing effect, the effect of groundwater flow is lower.