Integrated process optimization and life cycle analysis (LCA)-economic assessment for sustainable treatment of arsenic and fluoride-contaminated groundwater with co-existing iron

Abstract

The present work determined the influence of co-existing iron on the performance of the electrocoagulation (EC) process for the sustainable treatment of arsenic and fluoride-contaminated groundwater. Response surface methodology (RSM) was used to investigate the influence of arsenic (0.1–1.0 ppm), fluoride (2–6 ppm) and iron (0.5–1.5 ppm) concentrations, residence time (10–120 min), and current (0.2–0.8 A) on arsenic and fluoride removals. Further, predictive models were developed using RSM. Life cycle assessment (LCA) evaluated the environmental impacts, while genetic algorithm-based multi-objective optimization (GA-MOO) addressed the conflicting goals of maximizing the removals and minimizing environmental and economic burdens. This approach helps to make the treatment align with sustainable development goals (SDG-6, 12 and 13). The optimized conditions for water treatment with 0.55 ppm As, 1 ppm Fe and 6 ppm F^- are current 0.22 A and residence time 110.14 min, with 99.20 % arsenic and 93.82 % fluoride removals. The presence/addition of iron reduced electro-dissolved aluminium and electricity requirements by 50 % compared to iron-free water. LCA shows a significant reduction in environmental impacts with the increase in iron concentration in all the impact categories. The economic evaluation has shown a substantial reduction in treatment cost with an increase in iron concentration, demonstrating the economic viability of the EC process with co-existing iron. Characterization of the sludge using XRD, FESEM, EDX, XRF, and XPS confirmed the presence of contaminants, offering insights into the mechanisms responsible for their removal. Therefore, findings of this study highlight the efficient performance of the EC process with co-existing iron as an efficient and economical solution for groundwater treatment.