Question

A biological reactor treats water for a small community in Mthatha. The reactor acts as a perfectly mixed aeration pond. The pond receives an incoming 50 m3 /d of contaminated water with a BOD5 of 345 mg/L. The target discharge BOD5 is 30 mg/L which the treatment plant must achieve before the treated water can be discharged into the environment. The kinetic constants for the system are Ks = 120 mg/L BOD5, kd = 0.10 d-1 , µm = 1.85 d-1 , and Y = 0.75 mg VSS/mg BOD5

i. Draw a diagram of the above scenario annotating all parameters.

ii. Determine the detention time required in the pond to achieve the target discharge BOD5?

iii. Determine the amount of microbes in kg that will be produced in the pond per day?

Answer 1