Removal of particulate organic matter
Treatment efficiency
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
0.5
1.5
2
2.5
3
Dimensionless load
3.5
as 1/2
_ _ 5._1_
k1/2AA
4
4.5
Fig 5.23 Treatment efficiency as a function with the load for a half order process with
a degree of hydrolysis of1.0. /20/
Flow of wastewater:
Starch concentration:
Biofilm area:
Tank volume:
Oxygen concentration:
0=500 m 3 /d
C1 = 100 g COD/m 3
A2• =500m 2
V2=5 m 3
3
Co2.2 = 1 g/m
5
and as a preliminary assumption, the oxygen is assumed to be limiting for the removal:
186
Internal oxygen removal
Diffusional coeff. for oxygen
Stoichiometry
kovt,02 = 200 kg o2t(m 3 . d)
Do2
= 1.7 · 1 o- 4 m 2 td
VQ2,COD = 2.4 g COD/ g02
~L = (2Do2 · Co2,2J~ = [2 · 1.7 · 10-4 · 1 J~ = 41 m
kovt.02
2oo.ooo
1-l
The starch is hydrolyzed to glucose. The removal rate for glucose is:
rA,glu = ~L · kovt,02 · vo2,COD
= 41 . 10-6. 200,000. 2.4
= 20 g COD/(m 2 · d)
If all of the starch is hydrolyzed: DH = 1.0, the glucose balance would look as follows:
01·C1· DH=fA·A2*+01S3
A2*
500
3
S3 = C1 · DH- fA "Q1= 100 · 1.0-20 · 500 = 100-20 = 80g/m