biological n and p removal in activated sludge processes · biological n and p removal in activated...
TRANSCRIPT
© Sara Hallin
Biological N and P removal in
activated sludge processes
Sara Hallin
Department of Microbiology, SLU
Metabolism
Oxidation:
KOLFÖRENING KOLDIOXID + ELEKTRONER + VÄTEJONER
Reduktion:
SYRE + ELEKTRONER + VÄTEJONER VATTEN
Fullständig reaktion:
KOLFÖRENING + SYRE KOLDIOXID + VATTEN
BIOKEMISKT BUNDEN ENERGI
Fermentation:
GLUKOS ETANOL + KOLDIOXID
BIOKEMISKT BUNDEN ENERGI
Fermentation av socker till etanol och koldioxid. En del av kolet i
sockret har oxiderats till koldioxid medan en del har reducerats till
etanol (vanlig sprit).
Organiskt material bryts ner av mikroorganismer i luftningsbassängen.
Slammet (biomassa och organiskt material)avskiljs från det renade
vattnet i sedimenteringsbassängen. .
Traditionell ASP
NH4+ NO2
- NO3-
N2O
NO
NO2-
Organically bound nitrogen
org-NH2
N2
Nitrogen fixation
Nitrification
Assimilation
Assimilation Mineralization/
Ammonification
ATMOSPHERE
SOIL/WATER
Denitrification
Dissimilatory nitrate reduction to ammonium
Microbiological reactions in the N cycle
NO 2 NO N 2 O N 2 NO 2 NO N 2 O N 2 NO 3 NH 4 NH 2 OH NO 2 NO - 3 NH NH 2 OH NO 2 - - +
Kväverening
Nitrification - a two step oxidation process
NH3 NO2- NH2OH
Nitrite oxidation Ammonia oxidation
NO3-
N2O N2 NO3- NO2
- NO
N removal
Regulation of nitrous oxide emissions
O2
NH4+
H20 O2
ATP
Nitrification
NO2-
Redox
+
Glucose
2 ATP 2 NADH
Glykolysis
2 Pyruvate
2 GTP
6 CO2
TCA cycle 8 NADH
2 FADH
ATP NADH
FADH ATP
NO3- NO2
- NO N2O N2
- Denitrification
Ammonia oxidation: NH3 + 1,5O2 NO2
- + H+ + H2O
Periplams
OH-
Nitrite oxidation: NO2- + ½ O2 NO3
-
Metabolism
Cell constituents
Growth
Carbon fixation
• Lots of ATP needed!
• NADPH required!
1. ATP and NADH (reducing power) requirements in for
C-fixation in Calvin cycle
2. NADH formed by reverse e- flow:
Cyt c 2e- Cyt c
NAD+
O2 e-
e-
Energetic constraints
Denitrifier Diversity
Ammonia oxidizers
Bacteria Eukarya Archaea
Ammonia oxidizer diversity in soil
Am
mo
nia
ox
idiz
ing
arc
ha
ea
an
d
ba
cte
ria
(A
OA
an
d A
OB
), n
itri
te
ox
idiz
ing
ba
cte
ria
(N
OB
) The organisms
NH3 oxidizers Proteobacteria: Nitrosomonas Nitrosococcus Nitrosospira Thaumarchaeota: Nitrosopumilis…
NO2- oxidizers
Bacteria: Nitrobacter Nitrospira
amoA amoA
NH NH3 NH2OH NO2
-
Screening of a 1215 Mb soil metagenomic library
Treusch et al. 2005
Env Microbiol 7, 1985-1995
16S
AOA: Nitrosopumilis maritimus (●)
AOB: Nitrosomonas spp; Nitrosospira spp.(●) nitrification in ocean water () nitrification in soils ()
lowest Km for ammonium assimilation (
).
High-affinity ammonia oxidation by AOA
(Martens-Habbena et al. Nature, 2009)
NO 2 NO N 2 O N 2 NO 2 NO N 2 O N 2 NO 3 NH 4 NH 2 OH NO 2 NO - 3 NH NH 2 OH NO 2 - - +
Kväverening
NH4+ NO2
- NO3-
N2O
NO
NO2-
Organically bound nitrogen
org-NH2
N2
Nitrogen fixation
Nitrification
Assimilation
Assimilation Mineralization/
Ammonification
ATMOSPHERE
SOIL/WATER
Denitrification
Dissimilatory nitrate reduction to ammonium
Microbiological reactions in the N cycle
Denitrification Pathway
O2 + = NO3
-/ NO2
-
Denitrification pathway
Denitrification: anaerobic respiration
Organic compound CO2
Biosynthesis
Carbon flow
NO3-, (NO2
-, N2O)
Electron flow ATP
Denitrification
Cytoplasma
Periplasma
NO3-
NO2- NO3
-
H+
NADH2 NAD+
Proton motive
force
2e- 2e- 2e-
NO2- NO
NO N2O
N2O N2
e- nar nor
nir nos
Denitrifier Diversity
Denitrifiers
Bacteria Eukarya Archaea
Denitrifier diversity
O2
NH4+
H20 O2
ATP
Nitrifikation
NO2-
Redox
+
Glucose
2 ATP 2 NADH
Glykolysis
2 Pyruvate
2 GTP
6 CO2
TCA cycle 8 NADH
2 FADH
ATP NADH
FADH ATP
NO3- NO2
- NO N2O N2
- Denitrifikation
Nitrifierande bakterier Denitrifierande bakterier
•Nitrifierare finns i mark och vatten •Bara några få arter •Nitrifikation är två energigivande processer som utförs av två olika grupper av bakterier •Nitrifierare växer långsamt
•Denitrifierare finns nästan överallt •Många bakteriesläkten •Denitrifikation är en alternativ andningsprocess i frånvaro av syre •Denitrifierare är växer oftast snabbt
Effekt av extern kolkälla på kvävereningen
0
20
40
60
80
100
0 10 20 30 40 50 60
Nitro
ge
n r
edu
ction
(%)
Time (days)
R
E
a
0
5
10
15
0 10 20 30 40 50 60
Denitri
ficati
on r
ate
(mg
N2O
-N g
-1 V
SS
h-1
)
Time (days)
R
E
b
1. Kvävereningsgrad (%): 2. Denitrifikastionskapacitet:
Tid (dagar) Tid (dagar)
R = Fördenitrifikation utan extern kolkälla E = Fördenitrifikation med etanoltillsats
Intermittent dosering av etanol
i en fördenitrifikationsprocess
Hasselblad & Hallin. 1998. Wat. Sci.Technol.
NO 2 NO N 2 O N 2 NO 2 NO N 2 O N 2 NO 3 NH 4 NH 2 OH NO 2 NO - 3 NH NH 2 OH NO 2 - - +
Kväverening
NO 2 NO N 2 O N 2 NO 2 NO N 2 O N 2 NO 3 NH 4 NH 2 OH NO 2 NO - 3 NH NH 2 OH NO 2 - - +
N2O producing processes and NO3 leaching
NO
N 2 N O
NO3-
N 2 N 2 O
D I E T
A G R I C U L T U R E
E N V I R O N M E N T
World greenhouse gas emissions by sector
N2O N2 NO3- NO2
- NO
Regulation of N2O emissions
1/3 of denitrifier genomes lack nosZ (Jones et al. 2008 Molec Biol Evol)
0
0,2
0,4
0,6
0,8
Ratio of N2O-producers
N2O
/(N
2O
+ N
2)
Manipulation of soil denitrifier community showed direct causality link between the community composition and potential N2O emissions. (Philippot et al. 2011 Global Change Biol.)
Microbes without nosZ (N2O reductase gene)
40 m
ng N
g-
1 dry
soi
l h
-1
Importance of root derived carbon Cattle impact on the denitrifying commmunity
N E
S W
Low cattle impact
Medium cattle impact
High cattle impact
10
30
50
70
N2O/(N2O+N2)
1.102
2.102
3.102
Denitrifier genetically capable to reduce N2O (nosZ)
Gene
cop
y ng
-1 D
NA
Total bacteria (16S rRNA) 1. 104
2.104
3.104
4.104 Gene
cop
y ng
-1 D
NA
0.5 0.8
1.1 1.4
Proportion of denitrifiers genetically capable to reduce N2O (% nosZ/16S rDNA)
500
1500
2500
500
1500
2500
Potental denitrification
Environmental Microbiology (2009) 11(6), 1518-1526
Mapping field-scale spatial patterns of size and activity
of the denitrifier community
Laurent Philippot,1,2,* Jiri Ćuhel,3 Nicolas P A Saby,4
Dominique Chèneby,1,2 Alicia Chroňáková, 3 David Bru, 1,2
Dominique Arrouays4, Fabrice Martin Laurent1,2 and Miloslav Śimek3
nosZ
NO N2 NO3- NO2
- NO N2O NO NO
(From L. Philippot, INRA)
N2O N2 NO3- NO2
- NO
Regulation of N2O emissions
Microbes that only have nosZ (N2O reductase gene)
Some organisms only have nosZ and are potential N2O sinks. (Graf et al. in prep.)
Biological phosphorus
removal
ANAEROBIC AEROBIC
Energy
Phosphate
Short chain fatty acids
Energy Phosphate O2
CO2+H2O
Energy consumption for uptake of soluble organics. ATP and PO43- is released.
Energy is conserved as poly- phosphate granules. Uptake of PO4
3-. Consumption of stored products (PHB).
PHB synthesis & degradation
Acetoacetate ß-hyroxybutyryl-CoA
ß-hydroxybutyrate
Acetoacetyl-CoA
Poly-ß-hyroxybutyrate
(PHB)
Acetic acid
Acetyl-CoA
Biological phosphorus removal
PO43- O2
CO2+H2O Energy Energy PO4
3- Organics
Deni
trif
icat
ion
ANAEROBIC REACTOR AEROBIC REACTOR SEDIMENTATION
Recirculation of NO3-
N-removal in wetlands
CH4 O2
Diffusion through aerenchyma
Water
O2
CO2
CO2 CH4
O2 +NH3 NO3-
N2O
O2
CH4
H2+CO2
Acetate
Root exudates
N2
CO2
Reduction zone
NO3- Aerobic zone
N2O N2
Anaerobic zone
NO3-
Reduction zone
SO42-
Reduction zone
NO3-
O2
O2 + NH3
CH4 O2
Diffusion through aerenchyma
Water
O2
CO2
CO2 CH4
O2 +NH3 NO3-
N2O
O2
CH4
H2+CO2
Acetate
Root exudates
N2
CO2
Reduction zone
NO3- Aerobic zone
N2O N2
Anaerobic zone
NO3-
Reduction zone
SO42-
Reduction zone
NO3-
O2
O2 + NH3
Constructed wetlands
µg
N/g
DW
/h
Ruiz et al., 2009, FEMS Microbiol. Ecol.
Plants affect denitrification
We
tla
nd
pla
nts
eff
ec
ts
Rhiz
ospe
her
e
Sedim
ent
Low rates
High rates
Ruiz et al., 2009, FEMS Microbiol. Ecol.
DGGE of nosZ
• Typha and Fragmites select nosZ communities
• Seasonal differences
• Typha and Phragmites select nosZ communities • Typha and Phragmites increase denitrification activity • Seasonal differences Is increase in rhizosphere enough for increased capacity of wetland? • What about the abundance of denitrifiers?
Conclusions and outlook
Ekeby Constructed Wetland
Ekeby wetland in Eskilstuna
Total area: 36 ha
Flow: ~45000m3/day
Wa
ter-
flo
w p
ath
s
Kjellin et al., 2007, Wat. Res.
N-removal in mining impacted waters