IIT Guwahati unveils Rs 20 water purifier to remove fluoride, iron from groundwater

In a significant breakthrough for safe drinking water access in rural and fluoride-affected regions, researchers at the Indian Institute of Technology (IIT), Guwahati have developed a low-cost, community-scale water treatment system capable of removing fluoride and iron contaminants from groundwater. 

The system can purify up to 20,000 litres of water per day and costs just ₹20 per 1,000 litres, officials said.

The research, led by Professor Mihir Kumar Purkait from the Department of Chemical Engineering, has been published in the prestigious journal ACS ES&T Water. The innovative system offers a scalable, affordable, and energy-efficient solution to one of India’s persistent public health issues — excess fluoride in drinking water.

“Fluoride, though commonly found in dental products, can be highly toxic in large quantities and enters groundwater through both natural and human sources, such as agriculture and manufacturing,” said Prof. Purkait. Prolonged consumption of fluoride-contaminated water can cause skeletal fluorosis, a debilitating condition that hardens bones and stiffens joints, making movement painful.

Several Indian states — including Rajasthan, Telangana, Andhra Pradesh, Karnataka, Gujarat, and Haryana — continue to report dangerously high fluoride levels in groundwater.

To tackle this challenge, the IIT Guwahati team engineered a four-step electrocoagulation-based water treatment system. During electrolysis, hydrogen and oxygen bubbles interact with air bubbles, helping pollutants like fluoride and iron float to the surface and be removed. The researchers found that aluminum electrodes were most effective in treating water contaminated with fluoride, iron, and even arsenic.

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“The choice of electrode material was crucial. Aluminum proved optimal due to its high electro-positivity and low cost,” Prof. Purkait explained.

The system was tested under real-world conditions over a 12-week period. Results showed a 94% reduction in iron and 89% in fluoride levels — effectively bringing the contamination within limits prescribed by Indian safety standards.

The researchers highlight that the cost to treat 1,000 litres of water is just ₹20, making it extremely accessible for rural communities. Minimal supervision is required, and the technology has a projected lifespan of 15 years, with electrode replacement needed only once every six months.

Additionally, the study proposes a smart method to estimate the remaining life of electrodes using a built-in safety factor, enabling timely maintenance.

As a pilot initiative, the system has already been installed in Changsari, Assam, with the support of the Public Health Engineering Department of Assam and installation by Kakati Engineering Pvt Ltd. The pilot aims to demonstrate how the system can be deployed in underserved and remote communities.

Looking ahead, the IIT team is exploring the integration of renewable energy sources like solar or wind to power the system, and utilising hydrogen gas produced during electrocoagulation for energy. They are also working on adding smart features, including real-time sensors and automated controls, to further minimise human intervention.

“We’re aiming for a decentralised water treatment solution that can be easily adopted across India’s fluoride-affected and water-scarce regions,” Prof. Purkait added.

This innovation from IIT Guwahati marks a vital step forward in delivering safe, affordable, and sustainable drinking water solutions to millions living in water-stressed and contaminated areas.