Civil Engineering - GATE Exam Questions - Discussion
Discussion Forum : GATE Exam Questions - Section 3 (Q.No. 37)
37.
A waste water sample diluted to 100 times with aeration water had an initial dissolved oxygen (DO) of 7.0 mg/l and after 5 days of incubation at 20°C, the DO was zero. The BOD of waste water is :
Discussion:
11 comments Page 1 of 2.
Urjit said:
3 years ago
Answer is C because when the final Bod is 0 then we can't find the BOD.
(1)
Bantu said:
3 years ago
Option c is correct because We don't know at which time the oxygen becomes zero it may be the 3rd or 4th day.
Abhinav Bhardwaj said:
4 years ago
Even I think the answer should be C because at what time do become 0 is not known. It becomes after 5 days because reading is taken after 5 days but maybe at the 3rd to 4th day it became 0.
So, the answer cannot be determined.
So, the answer cannot be determined.
(1)
Nag said:
5 years ago
(7-0) *100 = 700mg/L.
Inital dissolved = 7.0mg/l.
FINAL = 0MG/l.
Inital dissolved = 7.0mg/l.
FINAL = 0MG/l.
Vishnu said:
5 years ago
The Correct answer is C.
Shantanu said:
6 years ago
Generally, the dilution ratio is 1 : 100.
Therefore the formula of BOD = loss of oxygen - dilution ratio.
Therefore the answer will be 700.
Therefore the formula of BOD = loss of oxygen - dilution ratio.
Therefore the answer will be 700.
UglyHAT said:
7 years ago
Let us assume the water sample to be 100l, that is diluted to 100 times.
Doi = 7 for 5 day,
Dof = 0,
Bod= (Doi-Dof)/(sample/solution),
Bod = (7-0)/(100/(100 * 100)),
= 700.
Doi = 7 for 5 day,
Dof = 0,
Bod= (Doi-Dof)/(sample/solution),
Bod = (7-0)/(100/(100 * 100)),
= 700.
Srq said:
8 years ago
Option C is correct. I too agree.
Prasad said:
8 years ago
Option C) Can't be determined is the correct answer.
Khatana said:
9 years ago
Read carefully @Shubham.
There is mentioned after 5 days.
There is mentioned after 5 days.
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