Civil Engineering - Waste Water Engineering - Discussion

Discussion Forum : Waste Water Engineering - Section 4 (Q.No. 6)
6.
3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 day-incubation at 20°C, the DO. concentration was 5 mg/l. The BOD of raw sewerage is
100 mg/l
200 mg/l
300 mg/l
400 mg/l.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
12 comments Page 2 of 2.

Bhabani said:   4 years ago
Thanks @Pravin @Riju.
(1)

Jahangir Abbas Sahil said:   4 years ago
DO = Dissolved Oxygen.
DO I= Initial = 8 mg/l,
DOF = Final = 5 mg/l.

DF= Dilution Factor.
Formula of BOD:
BOD = (DO I - DO F) * DF ---> (1)
DF = Total Vol/Vol of Sample
DF = 300/3
DF = 100
So, eq(1) becomes:
BOD = (8-5)*100.
BOD = 300 mg/l.
(7)


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