Waste water treatment of Leather Tanning Industries

Waste water treatment of Leather Tanning Industries

Sources:
Beam house washing, processing, soaking, tanning, liming, dehairing, deflushing, deliming, bating, picking, dyeing are the main source of waste water.



Characteristics
i. It contain excess NaCl.
ii. It has bad-odour.
iii. It has dark color.
iv. It has a high BOD value.
v. It has a high COD value.
vi. It contain suspended solids.


Bad Effects
i. The constituents of tannery effluent are deleterious and irrerespective.
ii. It imparts persistent dull brown to the receiving water.
iii. Highly repulsive odour is imparted to the receiving water.
iv. The acidic or alkaline effluent are corrosive to concrete and metal pipe.
v. Excess NaCl is corrosive.
vi. The effluent may be contain pathogenic bacteria..
vii. Dissolved Cr is harmful for fish.
viii. It has nonclear water.

How to Treatment those
i. Primary treatment includes screening to remove hairs, fleshing, fats etc.
ii. Secondary treatment includes processes such as chemicals coagulation and biological treatment.
iii. Removal of chromium followed by activated sludge process.