Measuring Gaseous Losses From Composting Hog Manure Separated
Solids -Preliminary Data- Jolene Rutter and Mario Tenuta
Soil Science Department, University of Manitoba, Winnipeg MB,
R3T 2N2.
In Manitoba manure management regulations have
changed to a phosphorus-based application rate. This has
producers interested in implementing manure separation
techniques as a means to remove the phosphorus (P) stored
in the separated solids (SS). However, a method that
utilizes
the low N:P separated solids is still required.
Composting the SS is a method that concentrates the P into
a smaller volume while stabilizing the nitrogen (N) losses,
thus reduce greenhouse gas (GHG) emissions (Larney et al.,
2006). Additionally, applied compost can capitalize on
nutrient supply and other value added benefits such as
disease control in potatoes (Molina, 2010).
Objectives: (a) Develop a method for mixing the SS with a
carbon source and setup a compost windrow, (b) determine
the gaseous losses during the composting of SS.
Soil Ecology Laboratory at The University of Manitoba
Biota
Management
Environment
As the project progresses objectives include:
a) Determine if altering the C:N has an effect on N flux
b) Identify patterns of N losses throughout the composting
process
c) Determine what effects composting SS has on P and
other physical properties
Larney, F.J., Sullivan D.M., Buckley K.E., Eghball, B. 2006. The
role of composting in recycling
manure nutrients. Canadian Journal of Soil Science.
86(4):597-611
Molina, O.I. 2010. Effect of green manures and organic
amendments on Verticillium wilt of potato in
Manitoba. M.Sc. University of Manitoba
For additional information or updates on current progress please
contact Jolene Rutter at [email protected]
Introduction
Fig 4. LI-8100 and FTIR system
Fig 5. LICOR long-term automated flux chamber
Fig 1.Alfa Laval centrifuge
Fig 2. Loading materials into fee d processor
Fig 3. Brown Bear © turning windrow
Fig 7. Compost windrow and GHG monitoring system
A LI-8100 automated chamber system with
a multiplexer (LICOR BioSciences) and
Fourier Transform Infrared Radiation (FTIR)
multi-gas analyzer (Gasmet DX4015) (Fig 4)
is used in series to analyze the volumetric gas
concentration of direct GHG’s:
a) Carbon Dioxide (CO2)
b) Methane (CH4)
c) Nitrous oxide (N2O)
and indirect GHG’s:
d) Nitrogen Dioxide (NO2 )
e) Ammonia (NH3)
LICOR long-term automated flux
chambers are used to collect gas
samples from the compost (Fig 5). A
pump moves air continuously in a
loop from the headspace of the
chamber through to the LI-8100 and
FTIR analyzers and back out to the
chamber headspace.
The analysis from the FTIR during
the observation is used to calculate the
flux rate. The ideal gas law converts
the volumetric concentration to the
mass. It is then divided by the
chamber area. From this, the flux rate
is determined by the linear regression
slope of μg m-2 versus time.
The GHG monitoring system includes
8 long-term automated flux chambers,
set-up on top of the windrow (Fig 7).
DOY vs N2O DOY vs N2O
DOY (Oct 2-4, 2011)
274.0 274.5 275.0 275.5 276.0 276.5 277.0
NH3 F
lux (u
g N / m
2 / s)
-2
0
2
4
6
8
10
12
14
Figure 8. Sample of flux rates from in-process composting.
Feedstock mixed on Sept 19, 2011
Methods: Compost Development An Alfa Laval centrifuge
separates the solids from the
liquid hog manure (Fig 1).
Feedstock material, SS
and wheat straw are
combined and mixed in a
feed processor (Fig 2) to the
ideal composting conditions
of C:N of 25:1 and water is
added to top the moisture
content up to 65% (Larney et
al., 2006).
A Brown Bear © compost
turner (Fig 3) turns the
windrow in order to maintain
the optimal conditions for
enhancing the biological
decomposition process.
The conditions monitored
include:
Temperature: > 30ºC
Moisture Content: 45-65%
Oxygen Content: > 13%
Methods: GHG Measurement
CO2
Flux
(ug
C / m
2 / s
)
0
2000
4000
6000
8000
N 2O
Flu
x (u
g N
/ m2 /
s)
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Results: GHG Flux Rates
Future Research
References
Fig 6. Observation sequence. Photo courtesy LICOR BIOSCIENCE
NO2
Flux
(ug
N / m
2 / s
)
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
CH4 F
lux
(ug
C / m
2 / s
)
-4
-3
-2
-1
0
1
2
3
(b)
(a)
(c)
(d)
(e)
Once the chamber is deployed
the observation begins. Emissions
from the compost build up in the
headspace. The observation
length is 3 minutes. Followed by
a 7.5 minute post-purge and 8.5
minute pre-purge of the next
chamber (Fig 6).
During the composting process CO2 is the highest and
most frequent flux emitter (Fig 8a).
