Perhaps one of the industry that is under the strong
radar of the environmental agencies is the Dyeing units and the Dyestuff
industries as a whole. The nature of pollution that accompanies this
industry is primarily due to the non-biodegradable nature of the dyes
along with the strong presence of toxic trace metals/acid/alkali/
carcinogenic aromatic amines traceable in the effluents. The following
table illustrates the pollutants associated with some of the very
Types of Pollution that is associated with various dyes:
||Nature of Pollution
||Salt, unfixed Dyes, copper salts, cationic fixing agents
||Salt, unfixed Dyes, Alkali
||Alkali, oxidizing agent, reducing agent
||Alkali, oxidizing agent, reducing agent, unfixed dyes
||Unfixed dyes, organic dyes
||Carriers, reducing agent, organic acids
|1:2 Metal complex dyes
||Metals, organic acids
It is a good omen that Dye manufacturers and dyeing
units have finally recognised the profoundity of the environmental
impact of using dyes. Brainstorming in this direction has led to the
development of new dyes that has:
Improvements in Dyes:
- Lower toxicity.
- Much improved levelling and exhaust characteristics.
- Narrower quality tolerances.
Following developments shows the
keenness of Dye manufacturers towards environment. Although these dyes
may be a bit expensive, but considering the potential long term savings
made from efficient dye use and a lower effluent cost. It is worth every
Improvement in Dyeing units:
- Development of fiber-reactive dyes for fibers like cellulosics,
that has stable fixation rates without regard to variations in
dyeing conditions, like liquor ratio, quantities of salt or alkali
temperature, time etc.
- Metal-free reactive dyes that has high fixation rates along with
minimum salt consumption.
- Low-sulphide or even sulphide-free dyes.
- Formulating granular dyestuff that are easy to handle and
dissolve and that reduces dust generation.
- The gradual withdrawal and newer replacement for azo-dyestuffs
that are threat as a potential carcinogenic.
- Researches made into dyestuffs with biodegradable formulating
The dyeing units are also not
left behind when it comes to addressing the problem of controlling
pollution. Some of this effective steps are highlighted below.
- Effective recycle of cone-dye cooling water.
- Air conditioning system water is recycled.
- Disseminating knowledge to workers for proper utilization of
water and power consumption.
- Installation of screens in drain lines that reduces the solid
particles in effluents.
- Proper implementation of a maintenance plan for steam traps.
- Digital monitoring systems for use in boilers.