Modeling of Cr (VI) Transport and In-Situ Remediation with Nano Scale Irons

Abstract

About 1,500,000 tons of chromites ore processing residues (COPR) containing 2 to 5% chromium, were generated from a chromites ore processing plant in Ranipet, Tamilnadu, INDIA, between 1975 to 1995. Since zero valent iron is a strong reducing agent it readily immobilize to Cr(III). In the present study, a 3D model, using finite element code, FEFLOW was used to evaluate the effect of Cr(VI) reduction, resulting from injection of nano scale zero valent iron (NZVI) particles. Initially the solute transport model was simulated to predict the distribution of the Cr(VI) in groundwater and calibrated. The NZVI injection was centered over the source zone and area of highest concentrations were divided into number of grids and the dosage of NZVI was determined. Column studies were undertaken to determine the rate of Cr(VI) reduction from the aqueous phase, by NZVI (RNIP), under laboratory conditions. The results illustrate the percentage reduction of Cr (VI) to Cr (III) and their spatial and temporal distribution in groundwater.