s) Measuring Gaseous Losses From Composting Hog ...DOY (Oct 2-4, 2011) 274.0 274.5 275.0 275.5 276.0...

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 jolene_rutter@hotmail.com

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).