Indian Institute of Technology Guwahati (IIT-G) researchers have developed a water-treatment technology that can remove arsenic and fluoride simultaneously from contaminated groundwater.
The research, the institute claimed in a statement issued on Tuesday, could be a vital contribution towards ensuring safer and affordable drinking water in regions affected by naturally-occurring groundwater pollution.
The researchers developed a rotating-anode electrocoagulation (RA-EC) reactor that achieved up to 98.2 percent arsenate and 91.8 percent fluoride removal within minutes.
The initial demonstration was performed at an estimated operating cost of Rs 18 to Rs 58 per 1,000 litres of treated water, depending on contaminant concentration.
The findings suggest that the technology could support a wide range of applications, including community drinking-water purification, decentralised rural water-treatment systems, treatment of arsenic and fluoride-contaminated groundwater, industrial wastewater remediation and integration with other advanced treatment processes such as adsorption and membrane filtration.
The findings were published in Chemical Engineering Journal, a leading peer-reviewed international journal that publishes high-impact research on chemical engineering, materials, energy, environmental technologies, and process engineering.
The paper was co-authored by Prof Mihir K. Purkait and research scholar, Mukesh Bharti from IIT Guwahati
Elaborating on the need for such research, Prof. Purkait from the department of chemical engineering, IIT Guwahati, said, “Groundwater serves as the primary source of drinking water for millions of people across India. In several regions, however, it contains both arsenic and fluoride, two contaminants that pose significant long-term health risks. Treating them together has remained particularly challenging because they behave differently during conventional purification processes and compete for removal sites.”
To address this challenge, the researchers from IIT-G developed a faster and more efficient reactor configuration capable of simultaneously removing both arsenic and fluoride.
Instead of using a stationary aluminium electrode, the IIT-G team redesigned the electrocoagulation process by developing a rotating aluminium anode that continuously improves mixing inside the reactor, enhances mass transfer, renews the electrode surface, and promotes the formation of pollutant-capturing aluminium hydroxide flocs.
When electricity passes through the reactor, aluminium ions and hydroxide ions combine to form microscopic flocs that bind with arsenic and fluoride, allowing both contaminants to be removed through adsorption, coagulation and precipitation. The rotating electrode substantially improves the efficiency of this process while reducing electrode passivation, a common limitation in conventional electrocoagulation systems.
Further, research scholar Bharti said, “We systematically evaluated how operating conditions, including rotational speed, current density, electrode spacing, and treatment time, influence performance. Our technology was also tested under realistic groundwater chemistry, including the presence of naturally occurring ions such as calcium, magnesium, bicarbonate, sulphate, and phosphate, as well as real groundwater samples collected from Assam.”
The next phase of the research will focus on developing a pilot-scale continuous-flow version of the reactor suitable for practical deployment.
