Question

Calculate the ultimate BOD of the river when an effluent is discharged into it.
Stream:
Q.=8.70 m/s
BOD = 6mg/L
Effluent:
Q=1.10 m/s
BOD = 50 mg/L
k, = 0.20/day
A) 10.9 mg/L
B) 5.4 mg/L

C) 2.6 mg/L
D) 12.6 mg/L
Answer?
​

Answer 1

Answer:

Explanation:10.9mg/L

Answer 2

The ultimate BOD of the river when an effluent is discharged into it is 10.9 mg/L

Given:

Stream:

Q = 8.70 m/s

BOD = 6mg/L

Effluent:

Q = 1.10 m/s

BOD = 50 mg/L

k = 0.20/day

To find:

Ultimate BOD of the river when an effluent is discharged.

Solution:

BOD means Biochemical oxygen demand. Through this we can measure the amount of oxygen required to break down by the microorganisms.

Here there is stream that has a certain BOD. To this stream an effluent is added with a certain BOD.

To find the ultimate BOD we need to calculate:

BODu = BOD concentration of the stream+BOD concentration of effluent

                           Flow rate of stream + Flow rate of effluent

BODu = BOD x Q. (stream) + BOD x Q (effluent)

                                     Q. + Q

Now substitute the values in the given formula,

BODu = 6 x 8.70 + 50 x 1.10

                   8.70 + 1.10

BODu = 52.2 + 55

                   9.8

BODu = 107.2/9.8

BODu = 10.9 mg/L

Therefore the ultimate BOD of the river is 10.9 mg/L

#SPJ3