The objectives of the case study by TIDE supported by Arghyam on the Tirupur textile industry cluster included:
- To collect data on the effluent load being discharged from textile processing units for the various operations requiring water (bleaching & dyeing)
- To understand the current treatment and disposal practices and the implication of the same on ground and surface water
- To review the technology options for reduction of pollution load to the limits recommended by the Tamil Nadu Pollution Control Board
- To document findings and share them among a larger audience so that recommendations and conclusions can be drawn from the case study.
The methodology comprised generation of primary data and compilation of available secondary data and its analysis. It was found that:
- There were 729 dyeing and bleaching units in Tiruppur generating 87 million liters of wastewater per day, 50 units in Coimbatore town generating 8 million liters of effluent per day, and around 10 units in Mettupalayam generating 7 million liters of effluent per day.
- The pollution load during the period 1980 – 2000 was total dissolved solids 23.54 lakh tons, Chloride 13.11 lakh tons, Sulphate 1.25 lakh tons, total suspended solids 0.97 lakh tons, Chemical oxygen demand 0.9 lakh tons, Biochemical oxygen 0.29 lakh tons, oil and grease 0.01 lakh tons.
- High concentration of Total Dissolved Solids and Chlorides persisted in ground and surface water in spite of having Common Effluent Treatment Plant and Individual Effluent Treatment Plant
- The current practice of water usage, effluent treatment and discharge and sludge storage and disposal were not sustainable and would cause irreparable damage to the ecosystem while threatening the livelihoods of the farmers in the vicinity of the textile units. There was need for intervention.
- Reverse Osmosis, was the technology option recommended by the TNPCB for zero effluent discharge and recycling of water. The financial issues involved in its adoption needed to be further understood.
The executive summary and a copy of the report can be downloaded from below: