Researchers from the Indian Institute of Technology (IIT) Guwahati have pioneered an environmentally friendly method to remove toxic lead from acidic industrial wastewater using naturally occurring bacteria. This biological process, which leverages sulphate-reducing bacteria, presents a sustainable alternative to conventional chemical treatments and can be applied beyond battery recycling facilities to wastewater from mining, smelting, and metallurgical industries, the institute announced on Wednesday.
Addressing Lead Pollution
Lead pollution from battery recycling is a critical global issue. The World Health Organization has highlighted the severe health risks of lead exposure, including impaired cognitive development in children, nervous system damage, and long-term health complications. Traditional chemical methods for lead removal are time-consuming and generate large quantities of lead-containing sludge that requires separate disposal.
Innovative Biological Approach
Prof. Pranab Kumar Ghosh from the Department of Civil Engineering at IIT Guwahati, along with research scholar Sreekanth Yadav Golla, utilized sulphate-reducing bacteria that thrive in oxygen-free environments. These bacteria convert sulphate in wastewater into sulphide, which then reacts with dissolved lead to form lead sulphide—a solid mineral that can be easily removed. The process also reduces wastewater acidity, enhancing bacterial survival and treatment efficiency.
Overcoming Challenges
A key challenge was the bacteria's survival in highly acidic and metal-rich conditions. The team developed a gradual acclimatization process, conditioning the bacteria to increasingly extreme environments. This enabled the biological reactor to effectively convert lead into stable lead sulphide, ensuring continuous wastewater treatment.
Environmental Safety
Sreekanth Yadav Golla noted that the bio-sludge produced contains lead in stable, non-mobile forms, minimizing environmental risk. The findings were published in the Journal of Environmental Chemical Engineering.
Future Plans
Looking ahead, the research team aims to enhance economic viability by using low-cost carbon sources, reducing sulphide in treated water, and exploring metal recovery options. This innovation marks a significant step toward sustainable industrial wastewater management.
