IIT Guwahati researchers have developed a bio-based wastewater treatment process that removes toxic lead, reduces acidity and offers a safer alternative for battery recycling and industrial effluent management.
Researchers at the Indian Institute of Technology (IIT) Guwahati have developed a sustainable biological process that efficiently removes toxic lead from highly acidic industrial wastewater, offering a promising alternative to conventional chemical treatment methods widely used in battery recycling industries.
The innovation comes amid growing global concern over lead pollution from industrial effluents, which remains a persistent environmental and public health challenge. The World Health Organization (WHO) has long warned that exposure to lead, especially among children, can severely damage brain development, impair the nervous system and cause irreversible lifelong health impacts.
Battery recycling facilities are among the major contributors to lead-contaminated wastewater worldwide. While conventional chemical treatment methods can remove lead to some extent, they are often slow, resource-intensive and generate large volumes of hazardous sludge that require further handling and disposal, adding to environmental burdens.
To address these limitations, a research team led by Civil Engineering Professor Pranab Kumar Ghosh, along with doctoral researcher Shrikant Yadav Galla, developed a bio-based treatment system using naturally occurring sulfate-reducing bacteria.
Explaining the mechanism, Prof. Ghosh said the bacteria convert sulfate present in wastewater into sulfide, which then reacts with dissolved lead to form lead sulfide, an insoluble and stable compound that can be easily separated from water.
“This process not only removes lead from wastewater but also reduces acidity, creating more favourable conditions for sustained bacterial activity and long-term treatment efficiency,” he said.
A key challenge in developing the system was ensuring bacterial survival under highly acidic conditions and elevated metal concentrations. To overcome this, the researchers gradually acclimatised the microbial culture to increasingly harsh environments, enabling it to remain active and stable over extended periods.
Experimental findings showed that the bioreactor system effectively converted dissolved lead into stable solid compounds. The treated wastewater showed significantly improved quality, while the process also reduced the volume of toxic sludge compared with conventional chemical methods.
Shrikant Yadav Galla said tests on the treated residue confirmed that most of the lead remained locked in a stable, immobile form, significantly lowering the risk of environmental recontamination.
The study, published in the Journal of Environmental Chemical Engineering, underscores the growing potential of microbial technologies in tackling some of the most persistent forms of industrial pollution, particularly in developing and industrialising regions where treatment infrastructure remains under pressure.
Researchers said the approach could pave the way for scalable, low-cost and environmentally safer wastewater treatment systems, especially for industries facing increasingly stringent environmental compliance requirements in the future.
