NIT Rourkela develops low-cost coal-based system to purify pesticide-contaminated agricultural wastewater

Researchers at the National Institute of Technology (NIT) Rourkela have developed an innovative wastewater treatment system that uses low-grade raw coal to remove harmful pesticides from agricultural runoff.  The breakthrough, led by Prof. Pradip Chowdhury and Ph.D. scholar Smruti Smita Sahoo from the Department of Chemical Engineering, promises a cost-effective and sustainable solution to India’s growing water contamination problem.

Excessive use of chemical pesticides in agriculture, especially during peak harvesting seasons, has long been a concern in India. Climatic changes, irregular monsoons, and untimely seasons often exacerbate pest-related crop damage, leading farmers to rely heavily on pesticides. These chemicals, including imidacloprid, chlorpyrifos, and atrazine, often leach into nearby freshwater sources, where they persist and accumulate, posing significant risks to human health, aquatic ecosystems, and the environment. 

Analytical studies conducted in central Odisha districts, Cuttack, Khordha, and Jagatsinghpur, revealed pesticide concentrations exceeding WHO limits, with imidacloprid at 20 ppm, chlorpyrifos at 16 ppm, and atrazine at 10 ppm.

To address this, the research team turned to low-grade coal from Mahanadi Coalfields Limited (MCL) in Odisha, which is largely underutilised due to high ash content and low calorific value. Characterisation of the coal revealed its porous structure and mineral properties suitable for adsorption. Using a lab-scale column setup, raw coal successfully removed up to six litres of pesticide-contaminated water with high efficiency, 98% for imidacloprid, 94% for chlorpyrifos, and 86% for atrazine.

“This approach not only offers a low-cost water treatment option but also turns underutilised coal into a resource for environmental remediation,” said Prof. Chowdhury. The team aims to further enhance the system using coal-derived advanced materials such as biochar and graphene oxide.

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The study, which outlines a sustainable ‘waste-to-wealth’ strategy using locally available resources, has been published in the International Journal of Environmental Research.