Assam: IIT Guwahati develops low-cost, natural method to remove toxic lead from water

Guwahati: Researchers at the Indian Institute of Technology (IIT) Guwahati have developed a low-cost, natural method to remove toxic lead from contaminated water using cyanobacteria, tiny photosynthetic microorganisms found in nature.

The study, published in the Journal of Hazardous Materials, was led by Prof. Debasish Das from the Department of Biosciences and Bioengineering, along with Dr. Abhijeet Mahana and Prof. Tapas K. Mandal from the Department of Chemical Engineering.

Lead contamination is a major environmental threat, affecting over 800 million children worldwide, including 275 million in India.

It enters water through industrial waste, agricultural runoff, and ageing pipelines, and can persist for decades, causing serious neurological, kidney, cardiovascular, and developmental problems.

Traditional treatment methods often rely on expensive chemicals or synthetic adsorbents, which may create secondary pollution.

To address this, IIT Guwahati researchers used bioremediation, a natural process in which microorganisms remove harmful substances.

The team focused on a light-dependent cyanobacterial species, Phormidium corium NRMC-50, and identified exopolysaccharides (EPS) produced by the bacteria as the most effective component for lead removal.

EPS was able to remove up to 92.5% of lead from contaminated water.

“This approach uses very little energy and can be scaled without complex infrastructure,” said Prof. Das. “Preliminary estimates indicate it could reduce treatment costs by 40–60% compared to conventional methods, with equal or better effectiveness. Its eco-friendly nature makes it ideal for industries and municipalities seeking affordable solutions.”

The researchers also noted that cyanobacteria can capture other pollutants, such as pesticides, dyes, and industrial chemicals.

The metals absorbed can later be recovered to produce biochar, bioplastics, or biofuels.

Cyanobacteria can reproduce on their own and need only sunlight, carbon dioxide, and a few nutrients, making this method a sustainable alternative to synthetic water treatments.

The team plans to scale the research from lab experiments to a pilot system to test the method in real wastewater conditions.