Oxygen
Nitrogen
Hydrogen
Hydrogen sulphide
10 days
20 days
30 days
60 days
Brick sewer
Cast iron sewer
R.C.C. sewer
Lead sewer
10 Degree Centigrade
15 Degree Centigrade
20 Degree Centigrade
25 Degree Centigrade
5-10 years
15-20 years
30-40 years
40-50 years