Question

A paper mill generates 0.087 m³/s of wastewater which has an ultimate BOD of 720 mg/L. The reaction rate constant at 20 °C was determined to be 6.48 hr^-1.

(a) Determine the BOD exerted in the water after 5 days at 20 °C (units: mg/L)

a) 1066

b) 533

c) 333

d)720

(b) Determine the BOD exerted in the water after 5 days at 10 °C (units: mg/L)                            

a)533

b) 227

c) 333

d )720 .

(c) If the paper mill effluent is discharged into a stream having a flow rate of 1.5 m³/s and a BOD₅=15 mg/L [rate constant and temperature similar to (a)], what will the resulting ultimate BOD be in the river immediately after mixing?                         

   a) 35

   b)681

c ) 58.6

d)53

Answer 1