Question

Determine the deoxygenation rate constant for the reach of Bald Eagle Creek below the wastewater outfall. The average speed of the stream flow in the creek is 30.0 m/d. The depth of the stream is 5.0 m. The bed-activity coefficient is 0.35.

The de-oxygenation rate is given by: ?? = ? + (?/ ?) η

where kd is the de-oxygenation rate at 20°C (d-1 ), v is the average stream flow velocity (m/s), k is the BOD rate constant (d-1 ), H is the average stream depth (m), and η is the bed-activity coefficient.

Answer 1

Solution :

The de-oxygenation rate is given by:

• ?? = ? + (?/ ?) η

where kd is the de-oxygenation rate at 20°C (d-1 ),

v is the average stream flow velocity (m/s),

k is the BOD rate constant (d-1 ),

H is the average stream depth (m), and

η is the bed-activity coefficient.

Data given:

v = 30 m/d

H = 5 m

η = 0.35

Put these values in above equation we will get,

?? = ? + (?/ ?) η

?? = ? + (30/ 5) * 0.35

Answer: ?? = ? + 2.1

Now Based on the value of k, we will get kd value.