GUWAHATI, June 19: Researchers from the Indian Institute of Technology-Guwahati (IIT-G) have developed a community scale water treatment system that removes fluoride and iron from groundwater.
The water treatment system can treat up to 20,000 litres of contaminated water per day, offering a low-cost solution for areas with poor access to safe drinking water.
The findings of the research have been published in the ACS ES&T Water journal in a paper co-authored by Prof. Mihir Kumar Purkait, along with post-doctoral research associates, Dr. Anweshan, and Dr Piyal Mondal, and research scholar Mukesh Bharti from the department of chemical engineering, IIT-G.
Fluoride, a mineral generally used in dental care products, pesticides, fertilisers and some industrial processes, can enter groundwater either naturally or through human activities such as agriculture and manufacturing.
Consumption of water with excess fluoride presence can lead to skeletal-fluorosis, a serious health condition in which bones harden and joints become stiff, making physical movement difficult and painful.
The research team developed a four-step system that ensures a cost-effective and energy-efficient technology for contaminated water treatment. The contaminated water goes through the process of – aeration, electrocoagulation, flocculation and filtration
Speaking about the developed technology, Prof Purkait said, “In the electrocoagulation process, an electric potential is applied to dissolve a sacrificial metal anode, typically aluminum or iron, generating coagulant species directly in the solution. Simultaneously, hydrogen gas evolves at the cathode. These coagulants help aggregate suspended solids and adsorb or precipitate dissolved contaminants.”
He further said that hydrogen and oxygen bubbles produced during electrolysis interact with air bubbles, assisting in lifting pollutant particles to the surface. The selection of electrode material depends on factors like low cost, low oxidation potential and high electro-positivity after dissolution.
The research team tested the developed system under real-world conditions for 12 weeks and recorded consistent performance. The results have shown removal of 94 percent iron and 89 percent fluoride from the wastewater, bringing the levels within safe limits set by Indian standards.
A key feature of the developed system is its cost effectiveness, with Rs 20 per 1000 litres of treated water, making it highly affordable.
The developed technology requires minimal supervision and has a projected lifespan of 15 years with electrode replacement scheduled every six months. The study proposes a method to estimate electrode life using a built-in safety factor to ensure timely maintenance.
As a pilot project, supported by the Assam public health engineering department, the developed technology has been successfully installed by Kakati Engineering Pvt. Ltd. in Changsari.
About the future scope of this research, Prof. Purkait said, “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.”
Additionally, the research team aims to combine this system with other water treatment methods to enhance its performance and make it a decentralised water treatment solution.