Breakthrough at IIT Guwahati: New Tech Cleans Arsenic-Contaminated Water in Minutes

Researchers at Indian Institute of Technology Guwahati have developed a new water treatment system capable of removing up to 99 per cent of arsenic from contaminated water, and at a significantly lower cost than conventional methods.

The newly developed electrocoagulation (EC) system can eliminate harmful contaminants within just a few minutes, making it especially useful for rural and semi-urban regions where advanced water treatment infrastructure is often unavailable.

A Growing Health Concern

With rapid industrialisation and increasing dependence on groundwater, arsenic contamination has become a serious public health issue in several parts of the world. Long-term exposure to arsenic can lead to organ damage and even cancer. According to the institute, nearly 140 million people globally are exposed to unsafe arsenic levels, with India, Bangladesh and parts of South America among the worst-affected regions.

While several treatment methods already exist, many require chemical additives, complex equipment and lengthy processing times. These systems are often difficult to operate in remote areas and may generate large amounts of sludge, increasing disposal costs.

How the New System Works

Unlike traditional methods, the IIT Guwahati team’s system does not rely on external chemicals. Instead, it uses electricity to release metal ions from electrodes placed in water. These ions bind with arsenic and other contaminants, allowing them to clump together and be removed easily.

To improve efficiency, the research team, led by Prof. Mihir Kumar Purkait from the Department of Chemical Engineering, introduced a rotating iron anode paired with a stationary cathode. The rotation enhances mixing and improves contaminant removal while preventing deposits from forming on the electrode surface.

The process also produces fine gas bubbles that help lift arsenic particles to the surface for easy separation. According to Prof. Purkait, the rotating electrode significantly boosts efficiency while keeping operational costs low.

Fast, Affordable and Efficient

Laboratory tests conducted on both synthetic and real groundwater samples showed that the system could treat one cubic metre of contaminated water using just 0.36 units of electricity. This translates to an estimated cost of around Rs 8–9 per 1,000 litres.

Under optimised conditions, arsenic levels were reduced to well below the World Health Organisation’s safe limit of 10 micrograms per litre within two to three minutes. The system also generated much less sludge compared to conventional electrocoagulation setups, making disposal easier.

Cost Advantage Over Traditional Systems

The EC system is considerably more affordable than membrane or reverse osmosis (RO)-based plants.

•    For small community plants (10–50 kilolitres per day), the EC system is estimated to cost between Rs 8–15 lakh, compared to Rs 12–20 lakh for conventional setups.

•    For medium-scale plants (100–500 kilolitres per day), the EC system costs Rs 30–80 lakh, while RO systems can exceed Rs 1–2 crore.

Maintenance costs are also lower, as the system mainly requires periodic electrode replacement rather than expensive membrane changes or heavy chemical dosing.

Next Steps

The research findings have been published in the international journal Separation and Purification Technology. The team now plans to test the system in real-field conditions, particularly in groundwater containing multiple contaminants such as fluoride and iron.

Discussions are underway with Assam-based M/S Kakati Engineering Pvt. Ltd. for fabrication and installation of the system. Commercial rollout will begin once funding support is secured.

If successfully implemented, the technology could offer a practical and affordable solution to arsenic contamination in vulnerable regions across India and beyond.

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