Evaluation of Air Injection and Extraction Tests at a Petroleum Contaminated Site,Korea

Air injection and extraction tests were conducted at a site where soils and groundwater were contaminated by petroleum hydrocarbons, mainly composed of TEX (toluene, ethylbenzene,and xylene). Storage tanks of petroleum hydrocarbons located less than 20 m away from the center of the test site were suspected to be the contamination source. Six injection/extraction wells and 21 monitoring wells were installed to evaluate performance and radius of influence with respect tosoil vapor extraction and air injection. Effective radius ofinfluence of the air injection tests based on pressure changes ranged from 3.3 to 10.5 m. Soil gas pressures, concentrationsof O₂, CH₄ and CO₂, and temperatures were measured during the tests. Air permeability and radii of influence with respect to gas pressure and oxygen supply by air injection were estimated. Dynamic changes in the concentrations of O₂, CH₄ and CO₂ gases and temperature around the extent of their ranges were detected asair was injected. We evaluated extensively the variations ofthe geochemical parameters that were indicative of active microbial degradation in this study.