In-situ Remediation of Arsenic polluted Groundwater using Permeable Reactive Barriers

Abstract

The foremost aim of this work was the development of a numerical modeling framework using hydrogeological parameters of general variations that are normally encountered in real field conditions in working of Permeable Reactive Barriers for arsenic remediation. Arsenic is found in groundwater in various places across the world including China, Gangetic basin of India, Bengal delta plains of India and Bangladesh, Nepal, Vietnam, etc. Due to millions of people in numerous countries being vulnerable to excessive amounts of arsenic through the ingestion of arsenic rich ground water, large scale toxicity of the human population by arsenic is a huge environmental hazard and requires scientific attention and interventions. The model developed to carry out simulations for the Permeable Reactive Barrier systems involved the use of previously available hydro-geologic and geochemical studies. Various non-specific cases were considered depending upon the usage of the Permeable Reactive Barrier systems and aquifer environment to generate different numerical simulations. The code used for these simulations was MODFLOW along with contaminant tracking code of MODPATH integrated with MODFLOW. The simulations were applied to understand the influence of variations in important factors required for the design of permeable barrier systems such as length and width of barrier and ratio of hydraulic conductivity of aquifer and the barrier to support the design and efficacy of the system for economical removal of arsenic from contaminated groundwater sites. The different important parameters for design were varied in a structured manner to corroborate permissible levels of arsenic in the treated plume of groundwater for any individual case. The findings of this study are of direct use for designing efficient Permeable Reactive Barrier for remediation of arsenic polluted groundwater.