1. A
Brief Review of
“Tannery”
By-
Saurabh Kulkarni

2. Scope of the Presentation:
• Necessity of Tanning
•Manufacturing Process Of leather
•Raw Materials And Chemicals used for tanning
• Waste characterization
•Suggested Treatment

3. Tanning and its Necessity:
Definition:
“Tanning is the process of making leather, which does not easily
decompose, from the skins of animals, which do.”
How does tanning work?
Tanning is a reaction between the collagen of the skin which is the
middle layer of the skin and different chemicals.
During tanning, Cross links are formed between the collagen
fiber structure and the fiber does not shrink due to bacterial action,
hydrolysis and high temperatures

4. Manufacturing process flow chart

5. Chemicals used:
Liming:
Slaked lime
Sodium sulfide
Sodium Hydroxide
Sodium Hydrosulfite
Arsenic sulfide
Calcium Hydrosulfide
Dimethyl Amine
Sodium Sulphydrate
Soaking:
Chloral
Sodium tri chloro phenate
Deliming:
Hydrochloric acid
Sulfuric acid
formic acid
Acetic acid
Chrome Tanning
Chromium sulfate
Chromium Chloride
Sodium Carbonate

6. Water Requirement l/d/ 100kg hide

7. Waste Water Generation l/d/100kg hide

8. Characteristics of Waste Water: Process wise
Waste
Water
Vol. Of
waste/100k
g skins in l
pH TS
mg/l
SS
mg/l
BOD5
Soaking 250-400 7.5-8 8000-28000 2500-4000 1100-2500
Liming 650-1000 10-12.5 16000-
45000
4500-6500 6000-9000
Deliming 700-800 3-9 1200-12000 200-1200 1000-2000
Vegetable
tanning
200-400 5-6.8 8000-50000 5000-20000 6000-12000
Pickling 200-300 2.9-4 16000-
45000
600-6000 600-2200
Chrome
tanning
400-500 2.6-3.2 2400-12000 300-1000 800-1200
Composite 3000-3500 7.5-10 10000- 1250-6000 2000-3000

9. Characteristics of Waste Water: Final output
Characteristics Amount Mg/l
Salinity 12000-23000
BOD 6000-12000
Cr-3 100-200
Cr-6 Nil
Chlorides 2000-2000
Colour Present Brownish red
Odour Strong Pungent

10. CPCB Norms
Pollutant Concentration in mg/l
pH 6.5-9.0
*BOD (at 27°C, 3 days) 100
Suspended solids 100
Total chromium (as Cr) 2
Oil and grease 10
Sulphides (as S) 1

11. Suggested Treatment

12. THANK YOU