Question

A new water treatment plant will treat a maximum flowrate of 95,000 m3 /d. You have been asked to design the chlorine contact basin. The plant must achieve 0.5 log inactivation of Giardia lamblia cysts with chlorine. The CT value for 0.5 log removal at the design conditions is 36 mg-min/L. The chlorine residual leaving the basin will be 1.5 mg/L.

a. Calculate the required volume of the chlorine contact basin if the basin is baffled so that the t10/τ ratio is 0.6.

b. Calculate the required volume of the chlorine contact basin if the basin is designed as a single tank that behaves hydraulically like a CMFR (the contact time for regulatory purposes is still t10).

Answer 1