Ecology Comes at a CostThere has been considerable keenness for maintaining ecology, particularly when the consumers around the world are getting more particular on this issue. There is another reason to it. As production costs rise and environmental regulations tighten worldwide, manufacturers in the clothing and textile industry are looking for ways of dealing with their production waste as economically as possible. That, however, can never mean simply choosing the cheapest option.

The recent court order to close down the dyeing units in Tirupur has led to a serious set-back to the garment production in this biggest hub of garment manufacturing in South India. The problem is not limited only to Tirupur, but covers emerging market players such as India and China, which face the same challenge, with pressures coming from domestic concerns about environmental problems, as well as the need to defend export reputations.

Effluents from processing tops the list of concerns. In India, for example, textile exports amount to around 13.5% of the country's total exports and its mills consume vast quantities of water. Dr Subrata Das, a textile technology specialist who heads Consumer Testing Laboratories (India) Ltd of Bangalore, says chemical processing of textiles during production generates about 70% of textile processing waste

Obviously, cleaning waste water for industrial re-use is a key goal here, but there are problems. Highly concentrated waste dye-bath water cannot be passed through standard reverse osmosis membrane filtering systems used to recycle water within industrial systems. So, it has to be combined first with washed water and then cleaned up, but how? Conventional biological means of treatment do not work because of the presence of toxic heavy metals from the processing, which kills off useful bacteria. What is more, most dyes in current use are still non-biodegradable.

One of the methods being tested out in major clothing manufacturing centre Tirupur, Tamil Nadu, to clean contaminated water before discharge to the environment is through a system using UV-ozonation. This breaks down heavy metals' molecular structure through the use of ultra-violet rays and makes clean-up treatment more effective as well as more economical. There is no one solution to handling textile waste water. Dennis Hunter, a chartered environmentalist and Chairman of Cambridge, UK-based environmental engineering specialists EEC Europe Ltd, explains: "The cleaning process depends on the way that the water has been used. Not every plant uses the same chemicals, for example. So, there are many steps involved."

That means screening for fluff and particles, skimming off oil and solvents where these have been used, mixing and homogenising the waste water so that treatment micro-organisms can work more effectively to clean it up and then neutralising it to take out excess acid. Even then, it may need to be de-inked, using oxidation or other methods to remove the remaining colour left by dye traces. However, if treated to this degree, the company then has water it can use again."