A Simulation Model of the Gravity Separation of Concentrated Solids
465
loye r thicknes s |
ICalculaf e initia l wate r velocit y I
I an d por e pressur e fo r an y layer ]
—| DO for eac h l a y e r
[
[
Calculat e gros s volume I
remove d fro m a laye r |
I Calculat e ne w reduced !
| volum e of a laye r
I
| Calculat e ne w reduce d porosit y |
Calculat e concentratio n
of o laye r
|Ca
" ^ * - | D 0 for eac h
1
layer |
1
Calculat e gros s
1
[consolidatio n of a layer ]
1
|calcuiat e 'K'o f a laye r |
1
Iculat e Ä P* o f
1
1 Calculat e ne w
[ velocit y of a I
a l a y e r
|
wate r 1
aye r |
I Ad d on e additiona l layer} -
'
I
'
—{Remov e constan t volume |
Pressur e i n
exces s of the
laye r abov e
Fig. 10. Constant Rate Thickener Computer Program Flow Diagram
SUMMARY AND RECOMMENDATIONS
This method of analysis presented here offers a more thorough theoretical analysis of
the thickening process and a substantially easier way to visualize the process as compared
to the empirical approaches which currently exist. The model offers an effective approach
to thickener design providing the sludge properties are known and can be estimated.
In the activated sludge process extensive research is needed to determine the effects of
changes in various operating parameters of the biological reaction on the sludge properties
outlined in this model in order to link the performance of the separation step to the
aeration step. Work is also needed to adapt this scheme to flotation thickeners and
centrifuge performance.