Advances in Air Sparging Technology of Saturated Zone

In situ air sparging involves injecting atmospheric air, under pressure, into the saturated zone to remove those volatile and semi-volatile organic groundwater contaminants and to promote their biodegradation by increasing subsurface oxygen concentrations. Due to the advantages of low cost, high efficiency and in situ constructability, groundwater Air Sparging (AS) technology has been quickly developed in the world recently. Based on the explanation of its remediation principle, literature review is done on the research advancement of air sparging technology mainly from three aspects. First, various methods for determination of the zone of influence and visualization techniques of air flow forms during air sparging are summarized. Then the influence of environmental geological conditions and construction technology parameters on the remediation effect of air sparging is systematically analyzed. Thereafter, two main types of air sparging theoretical models including lumped-parameter model and multiphase fluid flow model are discussed respectively in detail. Finally, based on the problems and difficulties existing in present research and engineering practice, several future tasks such as the enhancement remediation techniques in complex geological sites, microscopic intrinsic mechanisms, and establishment of related design and construction standards which require to be done are briefly analyzed.