A glass of water can look clear and still contain contaminants that cannot be seen, tasted, or smelled. In several parts of India, groundwater contains naturally occurring arsenic and fluoride, pollutants that can pose serious health risks when people are exposed to them over long periods.

The challenge becomes even bigger when both are present in the same water. Removing one contaminant does not necessarily mean removing the other, making treatment more complicated and often more expensive.

Now, researchers at IIT Guwahati have found a way to tackle both at the same time.

The team has developed a rotating-anode electrocoagulation (RA-EC) reactor that can remove up to 98.2% of arsenate and 91.8% of fluoride within minutes. Even more importantly, the initial demonstration puts the estimated operating cost at just Rs 18 to Rs 58 for every 1,000 litres of treated water, depending on the concentration of contaminants.

A small change that makes a big difference

So, how does it work?

The idea builds on a familiar water-treatment process called electrocoagulation, where electricity and metal electrodes are used to help pull pollutants out of water.

But the IIT Guwahati team made one important change. Instead of keeping the aluminium electrode stationary, they made it rotate.

That movement may sound simple, but it changes what happens inside the reactor. As the aluminium anode rotates, it improves the mixing of water, helps pollutants come into better contact with the treatment process and........

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