Indian researchers develop wastewater treatment solution

Indian researchers have developed an "improved" wastewater treatment solution that can completely reuse dye wastewater from textile industry, eliminating its toxicity and making it suitable for domestic and industrial usage.

It reduces the water treatment costs and facilitate the reuse of the water in dry regions.

The current three-stage treatment process for wastewater consisting of primary, secondary, and tertiary treatment is unable to treat toxic industrial wastewater.

The stand-alone Advanced Oxidation Process (AOP) treatment technique for colour and odour properties in industrial effluents (dye-based) may be insufficient to meet set government standards and is also limited due to the high cost of AOPs involving continuous supply of chemical reagents.

"This is because it cannot remove the synthetic industrial dyes and the effervescent colour and odour, which have a long-lasting carcinogenic and toxic effect on the ecological and especially aquatic life. In order to remove this toxicity, an upgraded solution with the AOP technology is the need of the day, a release from the Department of Science & Technology (DST) said.

Working towards this, researchers from the Indian Institute of Technology, Kanpur, with Malaviya National Institute of Technology, Jaipur, and MBM College, Jodhpur, have developed a modified AOP solution.

The completely modified treatment process consists of the primary dosing step followed by the sand filtration step, another AOP and subsequent carbon filtration step.

It eliminates the need for the conventional primary, secondary, and tertiary processes resulting in maximum colour removal and meets the inland water discharge standards.

Department of Science and Technology (DST), Water Technology Initiative (WTI), along with the Indian National Academy of Engineering (INAE) supported the development of this technology at a pilot level in collaboration with Laxmi Textile Prints, Jaipur for the commissioning of this pilot-scale plant at Textile Industrial Park, Jaipur.

The "much-improved" AOP technology targeting zero discharge water management system is being utilized for the complete reuse of industrial dye wastewater for domestic and industrial usage at a rate of 10 Kilo litres/day.

The treatment of toxic and highly carcinogenic industrial dyes of textile effluents is performed using this AOP technology for degrading and mineralizing recalcitrant organic matter from effluent wastewater.

It is a direct replacement of the existing treatment plant processes and consists of a low-cost solution of dye adsorption on acid-modified soil followed by a photochemical reaction step within a photocatalytic visible light filter and a unique carbon and PAN nano-mat fibre filtration process. Having been set up on a pilot basis, it remediates industrial wastewater.

The technology has resulted in the recuperation of 50 per cent of the treatment cost incurred from conventional processes for water treatment (especially due to the high cost of sludge disposability) in the water-scarce regions of Rajasthan.

Further, scaling up of this plant to 100 kilo litres/day capacity to meet the current industrial requirement is underway with automated plant operations, said a release.