IIT Guwahati unveils low-cost fluoride and iron removal system: Treats 1,000 litres of water for just Rs 20

Syllad | The Rising MeghalayaJune 19, 2025

Researchers at the Indian Institute of Technology Guwahati (IIT-G) have developed an affordable, energy-efficient water treatment system that removes fluoride and iron from contaminated groundwater. Capable of purifying up to 20,000 litres per day, the system costs only Rs 20 per 1,000 litres—offering a scalable solution for communities facing chronic water quality issues.

Tested under real-world conditions for 12 weeks, the system consistently removed 94% iron and 89% fluoride, bringing levels within safety standards set by the Indian government. The research findings were published in the journal ACS ES&T Water and co-authored by Prof. Mihir Kumar Purkait, Dr. Anweshan, Dr. Piyal Mondal, and research scholar Mukesh Bharti from IIT Guwahati’s Department of Chemical Engineering.

Fluoride contamination—common in several Indian states including Rajasthan, Andhra Pradesh, Telangana, and Gujarat—can cause severe health problems such as skeletal fluorosis, a painful condition that hardens bones and stiffens joints. The new system targets both fluoride and iron, two of the most persistent and harmful groundwater pollutants in rural India.

The technology follows a four-stage purification process – injecting oxygen using a custom-designed aerator to help remove dissolved iron, passing a mild electric current through aluminium electrodes to release ions that bind with contaminants, flocculation forming large clumps of bound particles which settle out of the water, using a multi-layer bed of coal, sand, and gravel to trap remaining impurities.

The core of the system is the electrocoagulation unit, where coagulants generated from aluminium electrodes attract and remove dissolved contaminants. According to Prof. Purkait, aluminium was chosen for its high electro-positivity, low cost, and effectiveness in eliminating iron, arsenic, and fluoride.

Designed to run with minimal supervision, the unit has a lifespan of 15 years, with aluminium electrodes requiring replacement every six months. Maintenance planning is built into the system using predictive models to estimate electrode wear.

As part of a pilot project supported by the Public Health Engineering Department of Assam, the system has been installed by Kakati Engineering Pvt. Ltd. in Changsari, Assam.

Looking ahead, the team is exploring solar and wind energy options to power the system and utilise the hydrogen gas produced during the treatment process. Future upgrades may include the integration of real-time sensors and automation, enabling deployment in remote and underserved regions with minimal human oversight.

Researchers also plan to integrate the system with other purification technologies to develop a modular, decentralized water treatment solution for broader application across the country.