Researchers at Indian Institute of Technology (IIT), Guwahati, have developed a low-cost community scale water treatment system that removes fluoride and iron from groundwater and can treat up to 20,000 litre of contaminated water per day, officials said.The findings of the research have been published in the prestigious ACS ES&T Water journal.The researchers claimed the system was highly affordable and could treat 1,000 litre of water at a paltry Rs 20.According to Mihir Kumar Purkait, Professor at Department of Chemical Engineering, IIT Guwahati, 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. In India, states including Rajasthan, Telangana, Andhra Pradesh, Karnataka, Haryana, and Gujarat, among others, face high levels of fluoride in groundwater," Purkait said.The IIT Guwahati research team developed a four-step system that ensures a cost-effective and energy-efficient technology for contaminated water treatment.Purkait said the 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."Among available options, aluminum has proven highly effective, particularly in the removal of iron, arsenic, and fluoride under optimal operational conditions," he said.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 per cent iron and 89 per cent fluoride from the wastewater, bringing the levels within safe limits set by Indian standards.