Environmental Engineering Reference
In-Depth Information
taBle 32.9
recommended volumetric cod loading for uasB reactors
at 30°c to achieve 85-95% cod removal
volumetric loading (g cod m
-1
/day)
Fraction as
Particulate
cod
Granular sludge
with high
tss removal
Granular sludge
with little
tss removal
Wastewater
cod (mg/l)
Flocculent
sludge
1000-2000
0.10-0.30
2-4
2-4
8-12
0.30-0.60
2-4
2-4
8-14
2000-6000
0.10-0.30
3-5
3-5
12-18
0.30-0.60
4-8
2-6
12-24
0.60-1.00
4-8
2-6
NA
6000-9000
0.10-0.30
4-6
4-6
15-20
0.30-0.60
5-7
3-7
15-24
0.60-1.00
6-8
3-8
NA
9000-18,000
0.10-0.30
5-8
4-6
15-24
0.30-0.60
NA
3-7
NA
0.60-1.00
NA
3-7
NA
NA, not applicable.
taBle 32.10
recommended volumetric organic loadings as a Function of
temperature for soluble cod substrates for 85 to 95% cod removal
(average sludge concentration Is 25 g/l)
volumetric loading (kg scod m
-3/
day)
vFa Wastewater
non-vFa Wastewater
temperature (°c)
range
typical
range
typical
15
2-4
3
2-3
2
20
4-6
5
2-4
3
25
6-12
6
4-8
4
30
10-18
12
8-12
10
35
15-24
18
12-18
14
40
20-32
25
15-24
18
Source:
Lettinga, G. and Hulshoff, L.W., UASB-process design for various types of wastewaters.
Water Sci Technol
, 24, 87-107, 1991.
32.4.2.3 upflow velocity
The upflow velocity, based on the flow rate and reactor area, is a critical design parameter.
Recommended design velocities are shown in Table 32.12. Temporary peak superficial velocities of
6 m∙s
-1
and 2 m∙s
-1
can be allowed for soluble and partly soluble wastewater, respectively.
For weaker wastewaters, the allowable velocity and reactor height will determine the UASB
reactor volume, and for stronger wastewater it will be determined by the volumetric COD loading.
