I am a student and in my project I need to be able to estimate size (at list area) of the primary settlement tank of which I know the flow rate per day (around 330 ML/d), and the actual retention time is less than 20 min. I am not an engineer (I study environmental management with chemistry background), and wonder if I could find any relationship between the flow rate and tank size if the retention time of 2 h is desired.

Thank you very much in advance,

Hajar