Remediation technologies for contaminated groundwater due to arsenic (As), mercury (Hg), and/or fluoride (F): A critical review and way forward to contribute to carbon neutrality

Groundwater contamination is a serious environmental problem that could hinder the world from contributing to the UN Sustainable Development Goals. This article provides an overview of how water scientists collectively address this issue and what innovative solutions can be identified to strengthen water resilience against climate change. For this purpose, this work critically reviews the applicability of water technologies for treatment of contaminated groundwater laden with As, Hg, or F through literature reviews using the Web of Sciences (WoS). Their benefits and limitations in applications are evaluated and compared. Their operational conditions such as pH, dose, reaction time, concentration of contaminants, and treatment performance are summarized. The implications of climate change on water scarcity and the roles of digitalization in water sector are discussed. It is conclusive from a literature survey of 225 articles (1997–2023) that both membrane filtration and adsorption have demonstrated outstanding removal over 80% for As concentrations from 0.025 to 1 mg/L. Reverse osmosis (RO) can completely remove As and F from contaminated groundwater. The performances of low-cost Fe0 in removing As and F are comparable to those of costly RO from 1 to 100 mg/L. Oxidation technology has proven its effectiveness in removing As up to 100 mg/L. Phytoremediation could treat Hg(II)-contaminated groundwater cost-effectively with its concentration less than 0.5 mg/L. The findings reveal the prowess of existing technologies in supplying clean water for global community. Although various technologies are available, the key factors in selecting the most suitable treatment for contaminated groundwater depend on technical applicability, groundwater properties, cost-effectiveness, and long-term impacts on the environment. As water quality are critical to public health, this suggests that the world needs to uncover how economic development and environmental protection can be achieved simultaneously, while dealing with the implications of climate change on water supply using digitalization in water sector.