Charcoal-Based Effluent Pre-Treatment Strategy for the Solvent Production Plant of a Heavy Water Plant

Abstract

This paper explores the application of activated charcoal adsorption for treating effluents generated from the Solvent Production Plant (SPP) at the Heavy Water Plant (HWP) in Tuticorin, India. The effluents, which contain organic solvents and hypersaline sodium or potassium chloride, present a significant challenge in terms of environmental compliance, specifically with the Tamil Nadu Pollution Control Board's (TNPCB) prescribed limits for Chemical Oxygen Demand (COD). The research methods in chemical effluent treatments were technically cumbersome, unsustainable and not-ecofriendly since it needs multiple precipitations using dangerous chemicals to attain prescribed pollution control board limits and generates substantial solid waste. To address these limitations, this study investigates the feasibility of charcoal adsorption as an alternative treatment method. The charcoal column setup, utilizing activated charcoal with a large surface area and a well-distributed pore structure, demonstrated a notable reduction in organic impurities, particularly in COD levels. Results show a significant decrease in COD, although the treated effluent still did not fully meet the TNPCB requirements. The study also explores the regeneration potential of activated charcoal using a 3% HCl solution, which proved effective for reusing the charcoal. Linear regression and correlation coefficient analyses indicated a strong relationship between the volume of effluent and reductions in COD and Total Organic Carbon (TOC), emphasizing the potential of this method for large-scale industrial applications. This research suggests that activated charcoal adsorption could serve as an effective pre-treatment method for integrating a more comprehensive Effluent Treatment System (ETS) at HWP Tuticorin.