Researchers at the Indian Institute of Technology Guwahati (IIT Guwahati) have developed a cost-effective community-scale water treatment unit capable of removing iron and fluoride from groundwater. The system, which can treat up to 20,000 litres of water daily, is designed to serve areas facing challenges in accessing safe drinking water.
According to the research team, the system effectively reduces iron levels by 94% and fluoride by 89%, bringing both within the safe limits prescribed under Indian drinking water standards. The total cost of treating 1,000 litres of water using the system is estimated at Rs. 20, making it a low-cost solution for widespread use.
The findings have been published in ACS ES&T Water, a peer-reviewed journal. The research was conducted by Prof. Mihir Kumar Purkait along with post-doctoral researchers Dr Anweshan and Dr Piyal Mondal, and research scholar Mukesh Bharti, all from the Department of Chemical Engineering at IIT Guwahati.
The unit operates through a four-step process. Water is first aerated using a specially designed aerator, which increases oxygen content to help remove dissolved iron. This is followed by electrocoagulation, where a low-voltage electric current passes through aluminium electrodes, generating metal ions that bind with impurities. In the next stage, the bound particles form larger clumps through flocculation, which then settle. Finally, the treated water passes through a multi-layer filtration bed made of coal, sand, and gravel to remove any remaining particles.
Explaining the system, Prof. Purkait said that aluminium electrodes were selected due to their affordability and effectiveness in removing several types of contaminants. He added that the gases generated during electrolysis assist in lifting pollutant particles to the surface, improving the system’s performance.
The system was tested over a 12-week period under field conditions, demonstrating consistent results. It is designed to operate with minimal supervision and has a projected operational life of 15 years. The electrodes require replacement approximately every six months. The team has also developed a method to estimate the life of the electrodes, incorporating a safety margin to support timely maintenance.
The project was implemented as a pilot initiative in Changsari, Assam, with technical support from Kakati Engineering Pvt. Ltd. and in coordination with the Public Health Engineering Department of Assam.
Looking ahead, the team is exploring options to integrate solar or wind energy to power the unit. Plans are also in place to make use of the hydrogen gas generated during electrocoagulation and to incorporate real-time sensors and automation to reduce manual involvement. The researchers are further considering combining this setup with other water purification technologies to make it suitable for decentralised use, particularly in rural or underserved regions.
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