Indian Scientists Develop Improved Wastewater Management System To Treat Toxic Textile Effluents

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

The treatment process can reduce water treatment costs and facilitate the reuse of the water in dry regions, the Ministry of Science and Technology said in a statement on Thursday (9 September).

The current 3-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 ecology and especially aquatic life, the ministry said.

In order to remove this toxicity, an upgraded solution with the AOP technology is the need of the day.

This 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) Government of India (GoI) – 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 ministry said.

The much-improved AOP technology targeting zero discharge water management system is being utilised for the complete reuse of industrial dye wastewater for domestic and industrial usage at a rate of 10 Kilo litres per 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 per day capacity to meet the current industrial requirement is underway with automated plant operations, it said.