Assam: Revolutionary water treatment system costs just Rs 20 per 1,000 litres

Scientists at the Indian Institute of Technology Guwahati have developed a game-changing water treatment system that could transform access to safe drinking water across India's fluoride-affected regions. The innovative technology treats contaminated groundwater for just Rs 20 per 1,000 litres while processing up to 20,000 litres daily.

The four-step treatment system addresses a critical health crisis affecting millions of Indians, particularly in states like Rajasthan, Telangana, Andhra Pradesh, Karnataka, Haryana, and Gujarat, where excessive fluoride in groundwater causes skeletal fluorosis—a debilitating condition that hardens bones and stiffens joints.

Professor Mihir Kumar Purkait from the Department of Chemical Engineering led the research team that spent 12 weeks testing the system under real-world conditions. Their findings, published in the prestigious ACS ES&T Water journal, demonstrate the technology's ability to remove 94 per cent of iron and 89 per cent of fluoride from contaminated water, bringing levels within Indian safety standards.

The treatment process begins with aeration, where a specially designed aerator adds oxygen to remove dissolved iron. The water then passes through an electrocoagulation unit, where a mild electric current flows through aluminum electrodes, releasing charged metal particles that bind with contaminants.

"An electric potential is applied to dissolve a sacrificial metal anode, typically aluminium or iron, generating coagulant species directly in the solution," explained Professor Purkait. "These coagulants help aggregate suspended solids and adsorb or precipitate dissolved contaminants."

During the third stage, flocculation and settling, the bound contaminants form large clumps that settle in a specialised chamber. Finally, the water passes through a multi-layer filter containing coal, sand, and gravel to remove remaining impurities.

The system's affordability stems from its energy-efficient design and minimal maintenance requirements. With a projected 15-year lifespan and electrode replacements needed only every six months, the technology requires minimal supervision while delivering consistent results.

A pilot installation has already been completed in Changsari, Assam, through collaboration with the state's Public Health Engineering Department and Kakati Engineering Private Limited, demonstrating the system's practical viability.

Looking ahead, the research team is exploring renewable energy integration to make the system completely self-sufficient. "We are also exploring the use of solar or wind power to operate the unit and to utilise the hydrogen gas generated during the electrocoagulation process," Professor Purkait noted.

The team plans to incorporate smart technologies, including real-time sensors and automated controls, to reduce manual intervention further, making the system ideal for remote and underserved communities. They also aim to combine this technology with other water treatment methods to create a comprehensive decentralised water treatment solution.

For regions where fluoride contamination has long been a barrier to safe drinking water access, this breakthrough offers hope for communities that have struggled with expensive and complex treatment options. The technology's combination of effectiveness, affordability, and simplicity positions it as a potential solution to one of India's most pressing public health challenges.

The research involved post-doctoral associates Dr Anweshan and Dr Piyal Mondal, along with research scholar Mukesh Bharti, all from IIT Guwahati's Department of Chemical Engineering.