Biofilters
Degree of hydrolysis
1.0
0.5
0 ~--------~--------~--------~----~
0
2
3
Combined load
1
a
2
_
1
( a ) (a )
kErA.E. ~.V2 - kErA.E . ~. v;
Fig 5.22 The degree of hydrolysis as a function of the water flow, the biofilm surface and the
water volume. /21/
(5.70)
E = CT,l- Cr,3 (5o,l + X&,l)- (So,3 + XR,3)
Cr,l
(So,l + XR,l)
(5.71)
as Cr= So+ XR
The result is shown in Fig 5.23 for the degree of hydrolysis 1.0.
In a biofilm reactor the removal only depends on the accessible biofilm area, and not
on the volume. By hydrolysis, the volume is included as a modifying factor because
the enzymes are washed off the reactor. If only the volume is reduced, the degree of
hydrolysis will decrease, SD,3 will decrease and the surface area specific removal
will decrease.
This effect is reinforced by the fact that the enzyme production depends on the
removal in the biofilm:
rA,E oc ~ L
By reduced volume the degree of hydrolysis decreases further because rA,E decreases by reduced removal.
Example 5.9
A filter plant is used for the treatment of wastewater from a potato flour factory whose
wastewater is assumed only to contain starch:
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