Emission of greenhouse gases from manure Sven G. Sommer Dept. of Agricultural Engineering Danish Institute of Agricultural Sciences
Jan 01, 2016
Emission of greenhouse gases from manure
Sven G. Sommer
Dept. of Agricultural Engineering
Danish Institute of Agricultural Sciences
Change in temperature
GHG emission inventories
Greenhouse gas emission, mill. ton CO2
0 10 20 30 40 50 60 70 80
Denmark
Agriculture
Manure+ruminants
Ruminants
Manure
Livestock manure is a source of greenhouse gases
• Nitrous oxide (N2O) produced during nitrification and denitrification of nitrogen in manure
• Methane (CH4) produced during anaerobic break down of organic matter in manure
Global warming potential of N2O and CH4
• N2O:310 times higher climate warming potential than that of carbon dioxide
• CH4: 21 times higher potential than that of carbon dioxide
Methane production
Biomasse:Animal manureOrganic waste
Hydrolysis
Dissolved substrate
Acidogenesis
H2+CO2
Acetognesis
VFA>C2
CH4+H2O+ CO2
CH3-COOH
Methanogenesis
Hydrolysis is process rate controlling
VFA transformation reduced due to:
High NH3
Sudden changes in environment
Feedback:
High VFA conc. reduces hydrolysis
Transformation of N in animal manure
nitrogen Manure
Interface
Atmosphere
)(
)()(
)(
)(
)()(
)()()(
23
2
22
2
2
4,3
,34
,3
NNO
ON
NON
EmissionEmission
ON
ON
Emission
NOrg
NHNHTAN
HNHNH
NH
Emission
L
G
L
G
L
L
G
Methane emissionManure housing
kg CO2-C eqv. LU-1Y-1
0 1500 3000 4500 6000
Manure stores outside
kg CO2-C eqv. LU-1Y-1
0 1500 3000 4500 6000
Beef deep litter
Fatteners slurry
Pigs straw flow
Cattle slurry
Cattle solid manure
Pig slurry
Pig solid manure
Slurry - methaneSommer et al. 2005;P. Kai, P.J. Dahl & H.D. Poulsen, 2005.
Stored frozen
Days from start of slurry addition
0 10 20 30 40
Met
hane
em
issi
on, g
C h
-1kg
-1[V
S]
0.000
0.005
0.010
0.015
0.020
0.025
0.030 Without inoculum10% inoculum
Fresh manure
Days from start of slurry addition
0 5 10 15 20M
etha
ne e
mis
sion
, g C
h-1
kg-1
[VS]
0.000
0.005
0.010
0.015
0.020
0.025
0.030(0.08)
Nitrous oxide
Manure housing
kg CO2-C eqv. LU-1Y-1
0 2000 4000 6000
Manure stores outside
kg CO2-C eqv. LU-1Y-1
0 100 200 300
Pig slurry
Dairy cow solid manure
Pigs deep litter
Cattle slurry
Cattle deep litter
Pig deep litter
Housing
Deep litter cattle - little N2O emission (Henriksen et al. 2000)
Temperature, oC
0 10 20 30 40 50
Dep
th, c
m
-100
-80
-60
-40
-20
0
Oxygen, vol%
0 5 10 15 20 25
TemperatureOxygen
Ammonium, g N kg(DM)-1
0 1 2 3 4 5 6 7 8 9
Dyb
de, c
m
-100
-80
-60
-40
-20
0
Nitrate, g N kg(DM)-1
0,019 0,020 0,021 0,022
Nitrate Ammonium
Temperature gradients in manure heaps
• High temperatures near heap surface
• Low temperatures in the centre of the heap
Anaerobic part: CH4
Intermediate zone
Aerobic zone: N2O
Covering a heap of manure, oxygen
Uncovered Covered
Centre
Ambient
10 cm below surface
Solid manure store – methane (Hansen MN et al. 2005)
Uncovered
Covered
Un-covered heap Covered heap
10 cm below surface
Centre
Solid manure store – nitrous oxide(Hansen MN et al. 2005)
b
0
200
400
600
800
1000
0 30 60 90 120
Days after start of storage
Con
c. o
f N2O
, pp
m
a
0
200
400
600
800
1000
0 30 60 90 120Days after start of storage
Con
c. o
f N2O
, pp
m
0
200
400
600
800
1000
0 30 60 90 120
Uncovered
Covered
10 cm below surface
Centre
Un-covered heap Covered heap
Stored slurry nitrous oxide
Nitrous oxide
N2O
em
issi
on, 1
0-3
g N
m-2
h-1
0
5
10
15
20
25
30
No coverSurface crustLeca pebblesStraw cover
Temperature
Day of the year
180 200 220 240 260
Slur
ry te
mpe
ratu
re, o C
10
15
20
25
LECA
Straw
Surface crust
Conclusion
• Inhouse manure stores:
– Methane production,
– No nitrous oxide emission (except from pig deep litter ?)
• Outside stores:
– Methane from slurry and solid manure,
– Nitrous oxide from solid manure and traces from crust on slurry