Chemical Engineering - Environmental Engineering - Discussion

Discussion Forum : Environmental Engineering - Section 6 (Q.No. 25)
25.
Fresh domestic sewage is __________ in color.
grey
dark brown
red
black
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
1 comments Page 1 of 1.

Parth said:   7 years ago
Fresh sewage is light brownish grey colour.

At a temperature of above 20°C, sewage will change from fresh to old in 2 - 6 hours.

The old sewage is converted to dark grey and black color due to anaerobic activities, known as stale or septic color.

Some industrial sewage also add color to domestic wastewater.

The grey, dark grey and black color is due to formation of sulfide produced under anaerobic conditions reacts with the metals present in wastewater.
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