Groundwater Cleanup by in-situ Sparging. I. Mathematical Modeling

The technique of in-situ sparging may provide a cheaper and more rapid method for removal of volatile organic compounds (VOCs) from groundwater than conventional pump and treat operations. A local equilibrium model is developed to describe in-situ sparging by means of a horizontal lateral slotted pipe at the bottom of a trench filled with crushed rock and normal to the direction of flow of the groundwater. The effects of air flow rate, groundwater flow rate, aquifer thickness, number of theoretical transfer units (related to axial dispersion), Henry's constant of the VOC, and initial VOC concentration are explored. Also, a method is developed for using vadose zone soil gas pressure measurements in the vicinity of a single sparging well to estimate the radius of influence of the well.