The river
The Noyyal runs through Tiruppur on its way to the Kaveri. For decades, effluent from the city’s bleaching and dyeing units flowed into it, damaging the river, the groundwater and the farms downstream.
The order
Litigation by farmers led to court orders requiring dyeing and bleaching units to stop discharging effluent altogether. Units that could not comply were shut: according to industry sources, about 729 factories closed in 2011.
What zero liquid discharge means
Under zero liquid discharge, or ZLD, no wastewater leaves the plant. Effluent is treated, filtered through membranes, and the remaining brine is evaporated. The recovered water returns to the dye house, and the recovered salt can be reused in dyeing.
Today Tiruppur recycles around 130 million litres of water a day.
An honest note
ZLD stopped new discharge, but recovery takes time. Groundwater around the river is still being restored, and the cluster continues to invest in treatment. It remains among the more demanding places in the world to colour cloth.
What to ask a supplier
- Which treatment plant handles their dyeing, and is it individual or a common effluent treatment plant?
- Do they hold a valid consent to operate from the Tamil Nadu Pollution Control Board?
- Can they share water recovery and reuse figures, with the period they cover?