Rs 20 for 1,000 Liters: IIT Guwahati’s Answer to Contaminated Water

Now, a group of researchers at the Indian Institute of Technology (IIT) Guwahati has developed a solution that could change this. They’ve built a low-cost, community-scale water purification system that can clean up to 20,000 liters of contaminated groundwater every day. The cost of treating 1,000 liters is just Rs 20. That makes it one of the most affordable solutions available for areas that lack access to clean water.

The system removes up to 94% iron and 89% fluoride from groundwater. It has already been successfully tested in Changsari, Assam, for 12 continuous weeks. The pilot project was carried out in collaboration with the Public Health Engineering Department of Assam and implemented by Kakati Engineering Pvt. Ltd.

Purification system works in 4 stages

The purification process involves four steps. In the first step, called aeration, a specially designed device adds oxygen to the water, which helps remove dissolved iron. In the second stage, known as electrocoagulation, a mild electric current passes through aluminum electrodes. This releases charged ions that attract and bind with pollutants.

Next comes flocculation and settling. Here, the bonded contaminants form clumps, which settle at the bottom of the chamber. Finally, in the fourth step, the water passes through a multi-layer filter made of coal, sand, and gravel, removing the remaining impurities.

Professor Mihir Kumar Purkait from the Department of Chemical Engineering led the project. He explained the technology in simple terms:

“Electrocoagulation generates coagulants directly in the water using electricity. These help bind and remove suspended particles. Gas bubbles formed during the process also lift impurities to the surface.”

The system is designed for long-term use. It requires minimal supervision and can last up to 15 years. The only routine maintenance is the replacement of electrodes every six months. To make this easier, the team has added a built-in alert system that signals when the electrodes need to be changed.

To further reduce the system's dependency on electricity, the researchers are exploring ways to power it using solar or wind energy. They also plan to capture the hydrogen gas produced during the purification process for additional use. The team is working on adding real-time sensors and automated controls, which would make the system even more suitable for remote areas with limited technical support.

The research was conducted by Prof. Purkait along with Dr. Anweshan, Dr. Piyal Mondal, and research scholar Mukesh Bharti. Their findings have been published in the peer-reviewed journal ACS ES&T Water.

This development is especially relevant for states like Rajasthan, Andhra Pradesh, Telangana, Karnataka, Gujarat, and Haryana, where fluoride contamination is a serious issue. In these regions, millions continue to rely on groundwater despite its risks. This new technology offers a practical and affordable way to reduce those risks.

Prof. Purkait said,

“By combining our system with smart technologies and renewable energy, we aim to make it more effective in remote and underserved areas.”

The team also plans to integrate this system with other water purification methods in the future. That could further improve its performance and make it adaptable to different types of water contamination.

This is not just a breakthrough in research. It’s a direct response to a public health crisis. With wider adoption, this technology has the potential to bring safe drinking water to villages that have never had it. It’s a step toward solving one of India’s most persistent and overlooked challenges.

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