Waste water treatment from Textile Industries

Textile Industry
Sources:
i. Cotton textile industry: Various operations involved in a cotton textile mill are combing, spinning, sizing, weaving and knitting are the main source of waste water.
ii. Synthetic textile industry: The operations like scouring, dyeing, rinsing, bleaching and finishing are the source of waste water.
iii. Wool industry: Various operations involved in a cotton textile mill are combing, spinning, sizing, weaving and knitting are the main source of waste water in wool industryalso.

Characteristics
i. The waste water generally coloured.
ii. It contain starch, polyvinyl alcohol and softners.
iii. It has a high BOD and high dissolved minerals.
iv. It contains suspended solids.
v. It contains soap-alkaly etec.

Effects
i. The dyes present impart persistent colour to the receiving sterams and interfere with photosynthesis of phytoplankton.
ii. The high pH is deleterious to aquatic life.
iii. The colloidal and suspended impurities causes turbidity in the receiving waters.
iv. The oil present interferes with the oxygenation of the receiving water stream.
v. The dissolved minerals increase salinity of the water.
vi. The toxic chemicals destroys fish and other microbial organism.
vii. It depletes the dissolved oxygen.
viii. The dissolved solid form incrustations on the surface of the surface of the sewers.
ix. The dissolved impurities cause corrosion in the metallic parts.


Treatment options
i. Segregation of wasters.
ii. Screening to remove coarse suspended matter.
iii. Removal of grease by equalization, neutralization.
iv. Chemical coagulation to remove colour, suspended and colloidal impurities.
v. Aerobic biological treatment.
vi. Finally tertiary treatment to remove dissolved solid.