Q1: The following data pertain to a sewage sample :
Initial D.O = 10 mg/l
Final D.O. = 10 mg/1 Dilution to 1%
The BOD of the given sewage sample is

ANS:D - 2 mg/1

I think this question will be wrong, the original question is given below.

The following data pertain to a sewage sample:

Intial D.O.=10mg/l,
Final D.O.=2mg/l,
Dilution to 1%.
The BOD of given sewage sample is;
Soln: BOD =(DO1-DO2 )*DF,
= (10 - 6)*1.
= 8 mg/l.
Where;

DO1 = intial D.O.
DO2 = final D.O.
DF = Dilution Factor.