Contributor, The Textile Industry and the Environment, UNEP

110 ANNEX E
The chemicals used in the process house included: caustic, enzymes for desizing, hydrogen peroxide
for bleaching, stabilizing agents for bleaching, soaps, detergents for washing, chemicking.
Dye House Sequence:
The dye house was found to have the following important operations:
I. Yardage dyeing
Beck dyeing (rope) for yardage
High pressure reactor for colton/polyester
Padding operation with aging
Jigger dyeing
2. Printing operations
Rotary screen
Semi-automatic flat screen
3. Washing and Curing t
4. Drying
Steam was used for heating in process. This was generated from a boiler house using rice hulls, with
fuel value of approximately 3150 kcal/kg. This unit produced 12 tannes of steam from approximately
16 tonnes of water per hour. This amounted to a daily steam usage of 288 tonnes of steam
per day.
The chemicals used in the process house include:
I. Dyesmffs: Reactive (colton), Direct (cotton), Dispersed (for cotton/poly blend), occasionally
some ingosal vat dyes are used for cert.ain shades (this dyestuff was not in use during the course
of this audit).
2. Chemical Auxiliaries for dyeing: Sodium chloride, sodium sulphate, caustic, surfactants,
carriers are used for the cotlon/poly blends, mineral acids, sodium bicarbonate, and urea.
3. Washing: Acetic acid, softeners, soaps
4. Boiler chemical for water treatment
The fabric preparation operation was continuous type and mostly automatic. Generally the process
sequence did not alter much except for chemicking operation which was more or Jess dependant on
the desired quality and finish of cloth. Accordingly, this operation was carried out in one or two
steps. This was the sale inf1uencing factor in the fabric preparation for the variation in resource consumption
and quantity and quality of generated effluent. [t was observed that the washing sequence
was the most often used in the entire process and it consumed a substantial amount of water (70070
of the total required for fabric preparation).
The sequence with tne maximum chemical consumption was identified to be dyeing and printing.
The most water intensive process here was once again that of washing. In the dye house, the processing
was typically batch and semi-automatic. All available processing capacity was not always in use due
to the ch.anging demands of colour fashion and fabric design. The use of dye types and discharges
varies with market conditions. These aspects of variability and non-operational equipment were given
due consideral ion while interpreting the audit data.
Quantification of Process Inputs and Outputs (Material Balance Study):
Quantifying the process inputs and outputs is a very important part of the auditing programme. In
order to enable this phase, initially a number of locations were examined to install flow measuring
devices like V-notches or flow meters.
After finalizing the unit operations and process f10w sheet the precise locations for installing the flow
measuring instruments (for both water consumption and generated eff1uent), were decided and the
works taken up accordingly. For example, the water meter on the main line was repaired for its minor
defects and was checked for calibration. Also it was decided 10 install a new V-notch permanently
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