Development and application of a contaminant transport model for groundwater remediation and reservoir protection: a case study from India

The upper Kodaganar basin, located in Dindigul district of Tamil Nadu, India, is composed of hard rock terrain. Groundwater is the major source of domestic and irrigation needs and it is being contaminated by tannery wastewater that is discharged into the nearby Sengulam Lake. The main aim of this work was to develop a contaminant transport model using the total dissolved solids (TDS) concentration of groundwater measured in the basin. The model was developed to predict the fate of contaminant in the aquifer. The TDS concentrations in the wells ranged from 249 to 20,120 mg/L, wherein extremely high values were observed in some of the severely contaminated wells. Three scenarios were proposed to predict the fate of the contaminant and to mitigate the effect of contaminant on groundwater receptors for the year 2020: scenario I: developed with the existing discharge conditions; scenario II: developed with discharge as per the standards; scenario III: developed with zero discharge. The results of this study showed that scenario III reduced the contaminated area from 12 km2 to 6 km2. The reduction in area for different concentration contours, namely 2000 mg/L, 5000 mg/L, 10,000 mg/L, and 15,000 mg/L, was 2 km2, 0.5 km2, 0.2 km2, and 0.1 km2, respectively, and the groundwater remediation was expected to take 2050 years. Hence, there is an urgent need for the application of clean and resource efficient technologies in process industries, and the implementation of suitable wastewater treatment technologies to prevent ground water pollution in the region.