Slow sand filtration water treatment plants
Practical Action
Sample design
DATA
UNITS
Flow
Qd = 0.002
m3 / s
Number of
units
N=2
[no
units]
Filtration
velocity
V1 = 1.5
m/h
Cleaning
velocity
V1 = 1
m / min
Velocity in
the
discharge
channel
Vc = 1.5
m/s
CRITERIA
A =_Q_
VF
D =_√4A_
√π
CALCULATIONS
A = 0.002 x 3600
2 x 15
A = 2.4
D = √4 x √2.4_
√π
RESULTS
UNITS
pre-filtration area
m2
pre-filtration
diameter
m
QL = A .VL
QL = 2.4 x 1 =0.04
60
cleaning volume
m3 / s
AC =_QL_
VC
b = √AC
h =_AC_
b
AC=_0.04_= 0.027
1.5
b = √0.027 =0.164
h = 0.027 = 0.16
0.164
canal section
canal width
canal height
m2
m
m
10