NIT-Rourkela team prepares system that uses low-grade raw coal to purify agricultural wastewater

Bhubaneswar: NIT Rourkela researchers have designed a wastewater treatment system that uses low-grade raw coal to purify agricultural wastewater containing pesticide residues. The researchers, whose work was published recently in the International Journal of Environmental Research, showed that coal, a fossil fuel and an environmentally polluting agent, can be used for the benefit of the environment. The system offers a low-cost and sustainable material for water treatment challenges.

Pradip Chowdhury, the professor who led the research team, along with research scholar Smruti Smita Sahoo, said, “The use of chemical pesticides is common in India and excess or unused pesticides frequently leach into agricultural drainages, ultimately reaching freshwater bodies where they persist and bioaccumulate due to their chemical stability. Several hazardous pesticides, which are banned in many European nations, are being used in India.”


“To evaluate the extent of pesticide-driven environmental contamination, agricultural wastewater samples were collected during the peak cultivation period from Cuttack, Khurda and Jagatsinghpur. Analytical findings revealed that concentrations of these pesticides exceeded the permissible limits set by the World Health Organization,” he added.

“We found pesticide concentration in the adjoining water bodies. The direct discharge of such contaminated effluents into rivers and lakes presents severe risks to the health of human beings and animals and to aquatic ecosystems and its surrounding environment. Many of these compounds are environmentally persistent, difficult to remove through conventional treatment processes and linked to endocrine disruption, hormonal imbalance and carcinogenic effects,” Chowdhury said.

India, the world’s second-largest coal producer, generates substantial quantities of low-grade coal that are largely underutilised in thermal power generation due to their high ash content and low calorific value. Although these coals have applications in gasification and other energy processes, a significant fraction remains abandoned.

“Coal samples collected from various locations of the state were pre-treated and characterised, revealing an ash content as high as 41%, porous structure, low gross calorific value and mineralogical characteristics favourable for water purification. To explore its potential, a lab-scale adsorption column was designed using raw coal as a low-cost adsorbent,” Chowdhury added.

Sahoo said the system developed in the lab showed satisfactory results in purifying the agricultural water with pesticide residues. “Future research will focus on developing advanced coal-derived carbon materials such as biochar and graphene oxide to further enhance treatment effectiveness,” she added.

Overall, this study proposes a sustainable ‘waste-to-wealth' strategy, demonstrating the potential of locally available resources to mitigate regional environmental pollution. It can be used as a net at the water releasing point of the farm for the purification of pesticide-mixed water, Chowdhury said.




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