Bài giảng công nghệ môi trường_24 ppt
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1
SPECIALIZED ENGLISH – SEMTESTER 5
VAN LANG UNIVERSITY
DEPARTMENT OF ENVIRONMENTAL TECHNOLOGY AND
MANAGEMENT
Chapter 24Chapter 24
FUNDAMENTALS OF BIOLOGICAL FUNDAMENTALS OF BIOLOGICAL
Dr. Tran Thi My Dieu
Sep. 2011
VAN LANG UNIVERSITY DENTEMA
WASTEWATER TREATMENT & REUSEWASTEWATER TREATMENT & REUSE
Bacterial growthBacterial growth
CONTENTSCONTENTS
Bacterial reproductionBacterial reproduction
Bacterial growth patterns in a batch reactorBacterial growth patterns in a batch reactor
VAN LANG UNIVERSITY DENTEMA
Bacterial
growth
patterns
in
a
batch
reactorBacterial
growth
patterns
in
a
batch
reactor
Bacterial growth and biomass yieldBacterial growth and biomass yield
BACTERIAL REPRODUCTIONBACTERIAL REPRODUCTION
Is it important in biological treatment?Is it important in biological treatment?
Binary fission
1 ori
g
inal cel
l
becomes 2
new ones
VAN LANG UNIVERSITY DENTEMA
Bacteria re
p
roduce b
y
Asexual mode
Budding
new
ones
Generation time ~ 20 min - days
Rapid change in biomass
BACTERIAL REPRODUCTIONBACTERIAL REPRODUCTION
Is it important in biological treatment?Is it important in biological treatment?
Spherical-shaped bacteria
VAN LANG UNIVERSITY DENTEMA
Assume
1
m diameter
Specific gravity of 1.0
Generation time ~ 30 min
Estimate bacteria mass after 12 h?
BACTERIAL REPRODUCTIONBACTERIAL REPRODUCTION
Is it important in biological treatment?Is it important in biological treatment?
Estimate bacteria mass after 12 h?
Weight of 1 cell ~ 5.0 x 10
-13
g
6
VAN LANG UNIVERSITY DENTEMA
Bacteria mass in 12 h ~ 8.4 x 10
-
6
g
Number of cell is quite large compared to the mass
In biological treatment systems, bacteria would not
continue to divide indefinitely because of
environmental limitations (substrate and nutrient)
BACTERIAL GROWTH PATTERNS IN A BACTERIAL GROWTH PATTERNS IN A
BATCH REACTORBATCH REACTOR
i
on
Lag
phase
Exponential
growth phase
Stationary
phase
Dead
phase
Substrate
To acclimate to
new environment
Multiplying at
max rate
VAN LANG UNIVERSITY DENTEMA
Concentrat
i
Time
Substrate
Biomass
Batch process biomass growth phases with
changed in substrate and biomass versus time
Amount of
growth is offset
by the death of
cells
No growth
2
BACTERIAL GROWTH AND BACTERIAL GROWTH AND
BIOMASS YIELDBIOMASS YIELD
Biomass yield Y =
g biomass produced
g substrate utilized
g biomass/g COD removed
VAN LANG UNIVERSITY DENTEMA
g biomass/g BOD removed
g biomass/g VFAs used
g biomass/g N-NH
4
oxidized
How to measure biomass?How to measure biomass?
BACTERIAL GROWTH AND BACTERIAL GROWTH AND
BIOMASS YIELDBIOMASS YIELD
How to measure biomass?How to measure biomass?
Increase in biomass can be measured by
Volatile suspended solids (VSS) or pCOD
VAN LANG UNIVERSITY DENTEMA
Volatile
suspended
solids
(VSS)
or
pCOD
Protein content (growth relates to true microbial mass)
DNA (if the reactor solids contain proteins)
ATP (if the reactor solid contain proteins)
Turbidity (if very low biomass concentration)
Bacterial cell counts
BACTERIAL GROWTH AND BACTERIAL GROWTH AND
BIOMASS YIELDBIOMASS YIELD
How to estimate biomass yield?How to estimate biomass yield?
Estimating biomass yield and oxygen
VAN LANG UNIVERSITY DENTEMA
requirements from stoichiometry
Estimating biomass yield from bioenergetics
BACTERIAL GROWTH AND BACTERIAL GROWTH AND
BIOMASS YIELDBIOMASS YIELD
Estimating biomass yield from stoichiometryEstimating biomass yield from stoichiometry
3C3C
66
HH
1212
OO
66
+ 8O+ 8O
22
+ 2NH+ 2NH
33
2C2C
55
HH
77
OO
22
N + 8CON + 8CO
22
+ 14H+ 14H
22
O O
Substrate Oxygen Nutrient Biomass
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3 x 180 8 x 32 2 x 17 2 x 113
The yield based on glucose consumedThe yield based on glucose consumed
Y =
g biomass produced
g glucose used
g C
5
H
7
O
2
N
g C
6
H
12
O
6
=
2 x 113
3 x 180
=
Y = 0.42 g cells/g glucose used
BACTERIAL GROWTH AND BACTERIAL GROWTH AND
BIOMASS YIELDBIOMASS YIELD
Estimating biomass yield from stoichiometryEstimating biomass yield from stoichiometry
In practice, used COD and VSS ~ organic & cells
Determine COD of glucose
C
H
O
+6O
6CO
+6H
O
VAN LANG UNIVERSITY DENTEMA
C
6
H
12
O
6
+
6O
2
6CO
2
+
6H
2
O
180 6 x 32
COD of glucose =
6 x 32
180
=
1.07 g O
2
/g glucose
Y =
g C
5
H
7
O
2
N
g (glucose as COD)
= 0.39 g
cells/g COD
2 x 113
3 x 180 x 1.07
=
BACTERIAL GROWTH AND BACTERIAL GROWTH AND
BIOMASS YIELDBIOMASS YIELD
Estimating oxygen requirement from stoichiometryEstimating oxygen requirement from stoichiometry
COD
utilized
= COD
cells
+ COD
of oxidized substrate
Oxygen consumed
VAN LANG UNIVERSITY DENTEMA
C
5
H
7
O
2
N + 5O
2
5CO
2
+ NH
3
+ 2H
2
O
COD
cells
=
5 x 32
113
= 1.42 gO
2
/g cells
3
BACTERIAL GROWTH AND BACTERIAL GROWTH AND
BIOMASS YIELDBIOMASS YIELD
Estimating oxygen requirement from stoichiometryEstimating oxygen requirement from stoichiometry
Oxygen consumed = COD
utilized
–COD
cells
=107
gO
/g glucose x 3 moles x 180 g glucose/mole
VAN LANG UNIVERSITY DENTEMA
=
1
.
07
gO
2
/g
glucose
x
3
moles
x
180
g
glucose/mole
- 1.42 gO
2
/g cells x 2 moles x 113 g cells/mole
= 577.8 g O
2
– 320.9 g O
2
= 256.88 g O
2
BACTERIAL GROWTH AND BACTERIAL GROWTH AND
BIOMASS YIELDBIOMASS YIELD
Estimating oxygen requirement from stoichiometryEstimating oxygen requirement from stoichiometry
Oxygen consumed per unit of COD used:
VAN LANG UNIVERSITY DENTEMA
Ox
yg
en consumed
Glucose as COD
=
256.88
g
O
2
3 moles x 1.07 gCOD/g
glucose x 180 g glucose/mole
= 0.44 g O
2
/g COD used
BACTERIAL GROWTH AND BACTERIAL GROWTH AND
BIOMASS YIELDBIOMASS YIELD
Estimating oxygen requirement from stoichiometryEstimating oxygen requirement from stoichiometry
Oxygen consumed per unit of COD used:
3C3C
66
HH
1212
OO
66
+ 8O+ 8O
22
+ 2NH+ 2NH
33
2C2C
55
HH
77
OO
22
N + 8CON + 8CO
22
+ 14H+ 14H
22
O O
VAN LANG UNIVERSITY DENTEMA
3 x 180 8 x 32
Oxygen consumed
Glucose as COD
=
8 x 32
3 x 180 x 1.07
= 0.44 g O
2
/g COD used
ASSIGNMENT 2ASSIGNMENT 2
Estimate biomass yield in term of g cells/g Estimate biomass yield in term of g cells/g
saccharosesaccharose used and g cells/g COD used ifused and g cells/g COD used if
VAN LANG UNIVERSITY DENTEMA
CC
1212
HH
2222
OO
1111
+ O+ O
22
+ NH+ NH
33
CC
55
HH
77
OO
22
N + CON + CO
22
+ H+ H
22
O O
