Indian researchers use waste material to clean industrial wastewater

BENGALURU: Indian researchers have developed a new kind of filter made from waste material that can help clean harmful pollutants from industrial wastewater.The study, published in the journal Water Environment Research, was led by Karan Gupta and Priyanka Katiyar from the Chemical Engineering Department of Shiv Nadar University, Delhi-NCR. The team has created a “biochar-infused membrane” using waste from industries such as spice processing and leather tanning.Biochar is a type of charcoal made by heating waste material at high temperatures with limited oxygen. Normally, spice residue and tannery sludge end up in landfills. The researchers converted this waste into biochar and blended it with polymers (plastic-like materials) to form thin, strong membranes that can filter pollutants.Industries such as textiles, tanneries, and pharmaceuticals discharge wastewater containing chemical dyes and antibiotic residues. If untreated, these can harm both human health and aquatic life. Pointing out that conventional treatment methods are often costly or inefficient, leaving a large portion of pollutants untreated, researchers said that according to the United Nations, nearly 80% of industrial wastewater worldwide is released into the environment without treatment.“Our study shows that using biochar membranes can provide a cheaper and faster way to clean industrial wastewater. Besides being inexpensive, these membranes enable a continuous filtration process and perform at levels similar to conventional treatment methods,” Gupta, assistant professor at the school of engineering, Shiv Nadar University, told TOI.The team said that the research demonstrated that membranes made with tannery waste biochar could remove not just dyes such as methylene blue and Congo red, but also antibiotics such as metronidazole and clindamycin hydrochloride. Membranes made from spice waste biochar were more effective against dyes but less effective against antibiotics.In tests, the membranes achieved pollutant removal rates of up to 83% for some dyes and 80% for certain antibiotics under controlled conditions. The membranes could also be reused up to five times after simple washing, making them more sustainable than one-time-use filters.Katiyar explained that the work combines her background in pollution control with Gupta’s expertise in polymer processing. “We have developed membranes that make use of spent industrial wastes to produce biochar, which otherwise would have ended up in landfills,” Gupta said.The researchers stressed that this is still at the proof-of-concept stage. Their next step is to scale up the work into a laboratory-level treatment plant to test real-world wastewater streams. If successful, such a system could offer industries a low-cost and environmentally friendly method of treating their effluents before discharge.