Arsenic Removal Technologies: A Critical Review of Environmental Impacts, Economic Viability, and Scale-Up Challenges

Arsenic-contaminated groundwater requires efficient, economically viable, and environmentally sustainable removal technologies. This review critically evaluates conventional treatment methods, including chemical coagulation/precipitation, adsorption, ion exchange, electrocoagulation (EC), and membrane filtration, alongside emerging approaches such as photocatalysis, magnetic nanomaterials, ozonation, bioremediation, and membrane distillation. A quantitative benchmarking of reported studies shows that membrane filtration, EC, and adsorption typically achieve 85–99% arsenic removal under optimized conditions, with energy consumption generally ranging from 0.2 to 4 kWh m–3, depending on process configuration. However, large-scale implementation is constrained by sludge and brine management, membrane fouling, electrode passivation, chemical demand, and associated operational costs. Emerging technologies demonstrate comparable removal efficiencies in laboratory-scale studies but face uncertainties regarding process stability, reaction kinetics, long-term performance, and techno-economic feasibility. Moreover, hybrid treatment systems have the potential to overcome the limitations of standalone processes, improve removal efficiency, and reduce environmental impacts, but require further lifecycle and cost assessments. By integrating performance metrics with environmental and economic trade-offs, this review identifies key scale-up challenges and outlines research priorities for sustainable arsenic mitigation.