460
A.S. Anderson and R.C. Hanson
Pores equal holes
Load on
spring
P
0
0
0
0
T=0
m 44+
4ÖÇ
Pres. A Pres.
PSF PSF
0
5
10
15
20
*Does not incude hydraulic pressure
due to weight of suspending fluid
Pres. A Pres.
PSF PSF
°
5
Load on
spring
P
0
0
0
2
T - l
Pres.
PSF
0
5
10
15
18
Pres.
PSF
0
A P r e s .
PSF
5
5
5
3
A P r e s
PSF
5
J)
12.27
14.08
Fig.2. A Simulation of the Thickening Process
and the final porosity that the mass will attain is estimated from the results of the settling
test after an extended period. The load distribution is then assumed to be a linear
function of the porosity between these two limits.
The last important concept in this model is that of a variable value for K. Intuitively,
the consolidation of flocculated particles will begin by drainage of water from the
largest open spaces between floe masses amd will be followed successively by drainage
from smaller regions within the mass. In this visualization of the consolidation model, the
effective particle diameter and surface area are changing parameters which must be
accounted for. The authors assume that this parameter is a linear function of the porosity
between its initial value and its ultimate value. A ratio K initial to K final is selected such
that it results in a calculated settling curve which closely approximates the real curve.
This ratio (R) is also considered to be a property of the particulates.
THE SETTLING TEST
A procedure is always required for estimating the properties of a particulate mass. The
settling test with emphasis on the SVI (sludge volume index) has traditionally been
utilized. For this simulation model, the common settling test is still recommended as the
principal test for determining particulate properties because it most closely approximates
the conditions which prevail in the separation unit; however, the emphasis is on the
determination of Kj (initial value of K), R the ratio of K initial to K final) and f u
(minimum value of the porosity which the particulates can attain under the conditions of
A.S. Anderson and R.C. Hanson
Pores equal holes
Load on
spring
P
0
0
0
0
T=0
m 44+
4ÖÇ
Pres. A Pres.
PSF PSF
0
5
10
15
20
*Does not incude hydraulic pressure
due to weight of suspending fluid
Pres. A Pres.
PSF PSF
°
5
Load on
spring
P
0
0
0
2
T - l
Pres.
PSF
0
5
10
15
18
Pres.
PSF
0
A P r e s .
PSF
5
5
5
3
A P r e s
PSF
5
J)
12.27
14.08
Fig.2. A Simulation of the Thickening Process
and the final porosity that the mass will attain is estimated from the results of the settling
test after an extended period. The load distribution is then assumed to be a linear
function of the porosity between these two limits.
The last important concept in this model is that of a variable value for K. Intuitively,
the consolidation of flocculated particles will begin by drainage of water from the
largest open spaces between floe masses amd will be followed successively by drainage
from smaller regions within the mass. In this visualization of the consolidation model, the
effective particle diameter and surface area are changing parameters which must be
accounted for. The authors assume that this parameter is a linear function of the porosity
between its initial value and its ultimate value. A ratio K initial to K final is selected such
that it results in a calculated settling curve which closely approximates the real curve.
This ratio (R) is also considered to be a property of the particulates.
THE SETTLING TEST
A procedure is always required for estimating the properties of a particulate mass. The
settling test with emphasis on the SVI (sludge volume index) has traditionally been
utilized. For this simulation model, the common settling test is still recommended as the
principal test for determining particulate properties because it most closely approximates
the conditions which prevail in the separation unit; however, the emphasis is on the
determination of Kj (initial value of K), R the ratio of K initial to K final) and f u
(minimum value of the porosity which the particulates can attain under the conditions of