Experimental and numerical investigation of Engineered Injection and Extraction (EIE) induced with three-dimensional flow field

Abstract

In situ groundwater remediation technique is a commonly adopted method for the treatment of contaminated groundwater and the porous media associated with it. Engineered Injection and Extraction (EIE) has evolved as an improved methodology for in situ remediation, where sequential injection and extraction of clean water around the treatment area enhances the spreading of treatment reagents by inducing additional flow fields. Conventional EIE studies were based on flow fields in two dimensions. There are only limited experimental and theoretical studies exploring the potential of inducing a three-dimensional flow field using EIE. The present study experimentally and numerically evaluates the effect of a three-dimensional flow field induced by partially screened wells. EIE experiments were conducted on a laboratory-scale aquifer model with laterite soil as the porous medium. Tracer transport in porous medium was studied by measuring the concentration at various observation points and enhanced dilution was observed when EIE was employed with partially screened wells. Experimental observations were also used to calibrate and validate the numerical model developed using Visual MODFLOW Flex. Enhancement in spreading was quantified in terms of concentration mass attenuation and maximum mass attenuation was observed when EIE was employed with partially screened wells.