Table 11.1
Volume of wastewater generated during various tanning processes (Dixit et al. 2015)
Process
Pollutant load kg/ton of hide
Waste water
generated
(kilolitres)
Chemical
oxygen
demand
Biochemical
oxygen demand
Chromium
Ammonical
nitrogen
Total
Kjeldahl
nitrogen
Suspended
solids
Sulphates Chlorides
Soaking
9.0–12.0
22–33
7–11
–
0.1–0.2
1–2
1 1
–17
1–2
8 5
–113
Liming
4.0–6.0
79–122
28–45
–
0.4–0.5
6–8
5 3
–97
1–2
5
–15
Deliming 1.5–2.0
13–20
5–9
–
2.6–3.9
3–5
8
–12
10–26
2–4
Chrome
tanning
1.0–2.0
7–11
2–4
2
–5
0.6–0.9
0.6–0.9
5–10
30–55
40–60
Post
tanning
1.0–1.5
24–40
8–15
1–2
0.3–0.5
1–2
6
–11
10–25
5–10
Finishing 1.0–2.0
0–5
0
–2
–
–
–
0–2
–
–
11 Solar Photocatalytic Treatment of Tannery Effluents
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