Life cycle assessment (LCA) of the arsenic and fluoride removal from groundwater through adsorption and electrocoagulation: A comparative study.

Abstract

The human health-related issues originating from the consumption of arsenic and fluoride-containing drinking water are major challenges worldwide. Amongst the different technologies available, electrocoagulation and adsorption are two promising technologies for simultaneous remediation of contaminants from groundwater. The present study evaluates and compares the environmental impacts of aluminium hydroxide/oxide nanoparticles (AHNP) adsorption and aluminium electrode electrocoagulation processes by performing their LCA. The Environmental impacts of both technologies were evaluated using Gabi software with the help of two mid-point methods (CML 2001 and TRACI). Evaluations are based on the treatment of 720L of arsenic(III) and fluoride contaminated water from initial concentrations of 0.5 and 10mg/L, respectively, to their WHO permissible limits. The management of spent materials has been considered for environmental impacts. The LCA analysis has shown that dissolution of aluminium electrode and electricity consumption in the electrochemical process are the significant contributors to environmental impacts in GWP, AP, ODP, ADP fossil, FAETP and HTP categories. Adsorption (GWP 35.2kg CO2 eq.) has almost eight times higher environmental impacts than electrocoagulation (GWP 4.5kg CO2 eq.) because in-situ generated coagulant has higher adsorption capacity than pre-precipitated adsorbents. The scenario analysis was performed with four different sources of electricity. The economic evaluation concludes that the combined cost of material and energy involved in the adsorption process (INR 0.7 per litre) is almost seven times higher than that of the electrocoagulation process (INR 0.1 per litre). Hence electrocoagulation is a more environment-friendly, low-cost technology to treat groundwater for community purposes.