Contributor, The Textile Industry and the Environment, UNEP

CASE STUDY 1
ANNEX C
CASE
STUDIES
ON
CLEANER
PRODUCTION
Water Conservation at Binny Textile Mills, Madras, India.
Major water pollution is generated by the following departments:
• Process and treatment
• Captive power generation unit (coal fired thermal power station)
• Sizing
• Yarn dyeing and printing
Wastewater and re-use measures undertaken include:
a) Re-use of pressure filter backwasb water
Easily se1tleab!e suspended solids is the main pollutant in the pressure filter backwash water. By collecting
this in a pond with a minimum hydraulic retention time of 12 hours the supernatant free from
suspended solids can be re-used for gardening purposes. Periodically the retained suspended solids
will be removed from the pond and disposed of as solid waste in a landfill site. The net effect is conservation
of 20 Ill'/day of fresh water used at present for gardening.
b) Re-use of wastewater from the dyeing and finishing department
About 1200 m'/day of fresh water (including evaporation loss) is used for quenching hot ash from
the boiler house before disposal. Laboratory experiments have confirmed thal it is feasible to re-use
the hard-to-treat wastewater from the dyeing department, instead of fresh water, for quenching purposes.
It was also confirmed tha.t due to adsorption of colour/dyes on the ash particles, there will
be about 200/0 reduction in BOD content in the fe-used dye-house wastewater. The net effect of this
approach is conservation of around 1200 m'/day fresh water and a reduction of around 520 kg
BOD/day.
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