Question

A settling tank with 50 foot diameter and a SWD of 9 feet treats

aflow of 15, 000 gpd. What is the detention time?

Answer 1

Detention time will be 9 days

Step-by-step explanation:

We have given diameter of setting tank d = 50 feet

Radius of setting tank
`r=(d)/(2)=(9)/(2)=25 feet`

SWD = 9 FEET

Area
`A=\pi r^2=3.14* 25^2=1962.5ft^2`

So volume
`V = area* SWD=1962.5* 9=17671.5ft^3`

We have given flow Q = 15000 gpd

So Q= 15000×0.13368 =2005.22
`ft^3` per day

Detention time is given by
`=(volume)/(Q)=(17671.5)/(2005.22)=9days`

So detention time will be 9 days