Given Information:
overflow rate = v = 60 m/d
volumetric flow rate = Q = 0.570 m³/s
depth of tank = h = 3 m
Required Information:
detention time = θ = ?
Answer:
detention time = θ = 3 days or 1.2 hours or 72 minutes or 4.32x10³ seconds
Explanation:
We know that the detention time is given by
θ = V/Q
Where V is the volume of tank and Q is the volumetric flow rate of the tank.
To find out the volume of tank, first we have to find the surface area of the tank.
As we know the volumetric flow rate is given by
Q = Av
A = Q/v
Where A is the surface area of tank and v is the over flow rate and Q is the volumetric flow rate.
First convert the overflow rate from m/d into m/s
1 day has 24 hours, each hour has 60 minutes, each minute has 60 seconds.
v = 60/(24*60*60)
v = 6.94x10⁻⁴ m/s
A = Q/v
A = 0.570/6.94x10⁻⁴
A = 821.32 m²
The volume of tank is given by
V = A*h
V = 821.32*3
V = 2463.97 m³
Finally, the detention time is
θ = V/Q
θ = 2463.97/0.570
Detention time in seconds:
θ = 4.32x10³ seconds
Detention time in minutes:
θ = 4.32x10³/60 = 72 minutes
Detention time in hours:
θ = 72/60 = 1.2 hours
Detention time in days:
θ = 1.2/24 = 0.05 days
