Choice of emission factors

The best way to determine emission factors is to conduct non-invasive or non-disturbing measurements of emissions in actual systems representative of those in use in the country. These field results can be used to develop models to estimate emission factors (Tier 3). Such measurements are difficult to conduct, and require significant resources and expertise, and equipment that may not be available. Thus, while such an approach is recommended to improve accuracy, it is not required for good practice. This section provides two alternatives for developing emission factors, with the selection of emission factors depending on the method (i.e., Tier 1 or Tier 2) chosen for estimating emissions.

Tier 1

When using the Tier 1 method, methane emission factors by livestock category or subcategory are used. Default emission factors by average annual temperature are presented in Table 10.14, Table 10.15, and Table 10.16 for each of the recommended population subcategories. These emission factors represent the range in manure volatile solids content and in manure management practices used in each region, as well as the difference in emissions due to temperature. Tables 10A-4 through 10A-9 located in Annex 10A.2 present the underlying assumptions used for each region. Countries using a Tier 1 method to estimate methane emissions from manure management should review the regional variables in these tables to identify the region that most closely matches their animal operations, and use the default emission factors for that region.

Table 10.14 shows the default emission factors for cattle, swine, and buffalo for each region and temperature classification. Emission factors are listed by the annual average temperature for the climate zone where the livestock manure is managed. The temperature data should be based on national meteorological statistics where available. Countries should estimate the percentage of animal populations in different temperature zones and compute a weighted average emission factor. Where this is not possible, the annual average temperature for the entire country could be utilized; however, this may not give an accurate estimate of emissions that are highly sensitive to temperature variations (e.g., liquid/slurry systems).

Tables 10.15 and 10.16 present the default manure management emission factors for other animal species. Separate emission factors are shown for developed and developing countries in Table 10.15, reflecting the general differences in feed intake and feed characteristics of the animals in the two regions. Except for poultry "layers (wet)," these emission factors reflect the fact that virtually all the manure from these animals is managed in 'dry' manure management systems, including pastures and ranges, drylots, and daily spreading on fields (Woodbury and Hashimoto, 1993).

Table 10.14

Manure management methane emission factors by temperature for Cattle, Swine, and Buffalo3

(KG CH4 HEAD-1 YR-1)

CH emission factors by average annual temperature (°C)b

Regional characteristics

Livestock species

Cool

Temperate

Warm

< 10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

> 28

North America: Liquid-based systems are commonly used for dairy cows and swine manure. Other cattle

Dairy Cows

48

50

53

55

58

63

65

68

y1

y4

y8

81

85

89

93

98

105

110

112

Other Cattle

1

1

1

1

1

2

2

2

2

2

2

2

2

2

2

2

2

2

2

manure is usually managed as a solid and deposited on pastures or ranges.

Market Swine

10

11

11

12

12

13

13

14

15

15

16

1y

18

18

19

20

22

23

23

Breeding Swine

19

20

21

22

23

24

26

2y

28

29

31

32

34

35

3y

39

41

44

45

Dairy Cows

21

23

25

2y

29

34

3y

40

43

4y

51

55

59

64

y0

y5

83

90

92

Western Europe: Liquid/slurry and pit storage systems are commonly used for cattle and swine manure. Limited cropland is available for spreading manure.

Other Cattle

6

y

y

8

8

10

11

12

13

14

15

16

1y

18

20

21

24

25

26

Market Swine

6

6

y

y

8

9

9

10

11

11

12

13

14

15

16

18

19

21

21

Breeding Swine

9

10

10

11

12

13

14

15

16

1y

19

20

22

23

25

2y

29

32

33

Buffalo

4

4

5

5

5

6

y

y

8

9

9

10

11

12

13

14

15

16

H

Dairy Cows

11

12

13

14

15

20

21

22

23

25

2y

28

30

33

35

3y

42

45

46

Eastern Europe: Solid based systems are used for the majority of manure. About one-third of livestock manure is managed in liquid-based systems.

Other Cattle

6

6

y

y

8

9

10

11

11

12

13

14

15

16

18

19

21

23

23

Market Swine

3

3

3

3

3

4

4

4

4

5

5

5

6

6

6

y

10

10

10

Breeding Swine

4

5

5

5

5

6

y

y

y

8

8

9

9

10

11

12

16

1y

H

Buffalo

5

5

5

6

6

y

8

8

9

10

11

11

12

13

15

16

H

19

19

Oceania: Most cattle manure is managed as a solid on pastures and ranges, except dairy cows where there is

Dairy Cows

23

24

25

26

26

2y

28

28

28

29

29

29

29

29

30

30

31

31

31

Other Cattle

1

1

1

1

1

2

2

2

2

2

2

2

2

2

2

2

2

2

2

some usage of lagoons. About half of the swine manure is managed in anaerobic lagoons.

Market Swine

11

11

12

12

12

13

13

13

13

13

13

13

13

13

13

13

13

13

13

Breeding Swine

20

20

21

21

22

22

23

23

23

23

23

24

24

24

24

24

24

24

24

Dairy Cows

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

2

2

2

Latin America: Almost all livestock manure is managed as a solid on pastures and ranges. Buffalo manure is deposited on pastures and ranges.

Other Cattle

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Swine

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

2

2

2

Buffalo

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

2

2

2

Chapter 10: Emissions from Livestock and Manure Management

Table 1G.14

Manure management methane emission factors by temperature for Cattle, Swine, and BuFFALOa

(kg CH4 head-1 yr-1)

CH emission factors by average annual temperature (°C)b

Regional characteristics

Livestock species

Cool

Temperate

Warm

< 1G

11

12

13

14

15

16

17

18

19

2G

21

22

23

24

25

26

27

> 28

Africa: Most livestock manure is managed as a solid on pastures and ranges. A smaller, but significant fraction is burned as fuel.

Dairy Cows

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Other Cattle

0

0

0

0

0

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Swine

0

0

0

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

2

Middle East: Over two-thirds of cattle manure is deposited on pastures and ranges. About one-third of

Dairy Cows

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

3

3

Other Cattle

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

swine manure is managed in liquid-based systems. Buffalo manure is burned for fuel or managed as a solid.

Swine

1

1

1

2

2

2

2

2

3

3

3

3

4

4

4

5

5

5

6

Buffalo

4

4

4

4

4

5

5

5

5

5

5

5

5

5

5

5

5

5

5

Asia: About half of cattle manure is used for fuel with the remainder managed in dry systems. Almost 40% of swine

Dairy Cows

9

10

10

11

12

13

14

15

16

17

18

20

21

23

24

26

28

31

31

Other Cattle

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

manure is managed as a liquid. Buffalo manure is managed in drylots and deposited in pastures and ranges.

Swine

2

2

2

2

2

3

3

3

3

4

4

4

5

5

5

6

6

7

7

Buffalo

1

1

1

1

1

2

2

2

2

2

2

2

2

2

2

2

2

2

2

Indian Subcontinent: About half of cattle and buffalo manure is used for fuel with the remainder managed in dry

Dairy Cows

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

6

6

Other Cattle

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

systems. About one-third of swine manure is managed as a liquid.

Swine

2

2

3

3

3

3

3

3

4

4

4

4

4

5

5

5

6

6

6

Buffalo

4

4

4

4

4

5

5

5

5

5

5

5

5

5

5

5

5

5

5

Source: See Annex 10A.2 , Tables 10A-4 to 10A-8 for derivation of these emission factors,

The uncertainty in these emission factors is +30 %.

a When selecting a default emission factor, be sure to consult the supporting tables in Annex 10A.2 for the distribution of manure management systems and animal waste characteristics used to estimate emissions. Select an emission factor for a region that most closely matches your own in these characteristics.

b All temperatures are not necessarily represented within every region. For example, there are no significant warm areas in Eastern or Western Europe. Similarly, there are no significant cool areas in Africa and the Middle East.

Note: Significant buffalo populations do not exist in North America, Oceania, or Africa.

Table 10.15

Manure management methane emission factors by temperature for Sheep, Goats, Camels, Horses, Mules and Asses, and PouLTRYa (kg CH4 head-1 yr-1)

Livestock

CH4 emission factor by average annual temperature (°C)

Cool (<15°C)

Temperate (15 to 25°C)

Warm (>25° C)

Sheep

Developed countries

0.19

0.28

0.37

Developing countries

0.10

0.15

0.20

Goats

Developed countries

0.13

0.20

0.26

Developing countries

0.11

0.17

0.22

Camels

Developed countries

1.58

2.37

3.17

Developing countries

1.28

1.92

2.56

Horses

Developed countries

1.56

2.34

3.13

Developing countries

1.09

1.64

2.19

Mules and Asses

Developed countries

0.76

1.10

1.52

Developing countries

0.60

0.90

1.20

Poultry

Developed countries

Layers (dry)b

0.03

0.03

0.03

Layers (wet)c

1.2

1.4

1.4

Broilers

0.02

0.02

0.02

Turkeys

0.09

0.09

0.09

Ducks

0.02

0.03

0.03

Developing countries

0.01

0.02

0.02

The uncertainty in these emission factors is +30 %.

Sources: Emission factors developed from: feed intake values and feed digestibilities used to develop the enteric fermentation emission factors (see Annex 10A.1); Except for poultry in developed countries, methane conversion factor (MCF), and maximum methane producing capacity (Bo) values reported in Woodbury and Hashimoto (1993). Poultry for developed countries was subdivided into five categories. Layers (dry) represent layers in a "without bedding" waste management system; layers (wet) represent layers in an anaerobic lagoon waste management system. For layers, volatile solids (VS) are values reported in USDA (1996); typical animal mass values are from ASAE (1999); and Bo values for Layers are values reported by Hill (1982). For broilers and turkeys, Bo values are from Hill (1984); typical animal mass values are from ASAE (1999); and VS values are those reported in USDA (1996). Bo values for ducks were transferred from broilers and turkeys; typical animal mass values are from MWPS-18; and VS values are from USDA, AWMFH. Typical mass of sheep, goats and horses, and VS and Bo values of goats and horses for developed countries updated according to the analysis of GHG inventories of Annex I countries. All manure, with the exception of Layers (wet), is assumed to be managed in dry systems, which is consistent with the manure management system usage reported in Woodbury and Hashimoto (1993).

a When selecting a default emission factor, be sure to consult the supporting tables in Annex 10A.2 for the distribution of manure management systems and animal waste characteristics used to estimate emissions. Select an emission factor for a region that most closely matches your own in these characteristics. b Layer operations that manage dry manure.

c Layer operations that manage manure as a liquid, such as stored in an anaerobic lagoon.

Table 10.16

Manure management methane emission factors for Deer, Reindeer, Rabbits, and fur-bearing animals

Livestock

CH4 emission factor (kg CH head-1 yr-1)

Deera

0.22

Reindeerb

0.36

Rabbitsc

0.08

Fur-bearing animals (e.g., fox, mink)b

0.68

The uncertainty in these emission factors is +30 %. a Sneath et al. (1997)

b Estimations of Agricultural University of Norway, Institute of Chemistry and Biotechnology, Section for Microbiology. c Judgement of the IPCC Expert Group

Tier 2

The Tier 2 method is applicable when Manure Management is a key source or when the data used to develop the default values do not correspond well with the country's livestock and manure management conditions. Because cattle, buffalo and swine characteristics and manure management systems can vary significantly by country, countries with large populations of these animals should consider using the Tier 2 method for estimating methane emissions. The Tier 2 method relies on two primary types of inputs that affect the calculation of methane emission factors from manure:

Manure characteristics: Includes the amount of volatile solids (VS) produced in the manure and the maximum amount of methane able to be produced from that manure (Bo). Production of manure VS can be estimated based on feed intake and digestibility, which are the variables also used to develop the Tier 2 enteric fermentation emission factors. Alternatively, VS production rates can be based on laboratory measurements of livestock manure. Bo varies by animal species and feed regimen and is a theoretical methane yield based on the amount of VS in the manure. Bedding materials (straw, sawdust, chippings, etc.) are not included in the VS modelled under the Tier 2 method. The type and use of these materials is highly variable from country to country. Since they typically are associated with solid storage systems, their contribution would not add significantly to overall methane production.

Manure management system characteristics: Includes the types of systems used to manage manure and a system-specific methane conversion factor (MCF) that reflects the portion of Bo that is achieved. Regional assessments of manure management systems are used to estimate the portion of the manure that is handled with each manure management technique. A description of manure management systems is included in Table 10.18. The system MCF varies with the manner in which the manure is managed and the climate, and can theoretically range from 0 to 100%. Both temperature and retention time play an important role in the calculation of the MCF. Manure that is managed as a liquid under warm conditions for an extended period of time promotes methane formation. These manure management conditions can have high MCFs, of 65 to 80%. Manure managed as dry material in cold climates does not readily produce methane, and consequently has an MCF of about 1%.

Development of Tier 2 emission factors involves determining a weighted average MCF using the estimates of the manure managed by each waste system within each climate region. The average MCF is then multiplied by the VS excretion rate and the Bo for the livestock categories. In equation form, the estimate is as follows:

Equation 10.23

CH4 emission factor from manure management

ef(t) = (VS(T) • 365)

" 3 MCFS k ' bo(T) • 0.67kg/m3 • Z—¡0JP• ms(T,S,k)

EF(T) = annual CH4 emission factor for livestock category T, kg CH4 animal-1 yr-1 VS(T) = daily volatile solid excreted for livestock category T, kg dry matter animal-1 day-1 365 = basis for calculating annual VS production, days yr-1

Bo(T) = maximum methane producing capacity for manure produced by livestock category T, m3 CH4 kg-1 of VS excreted

0.67 = conversion factor of m3 CH4 to kilograms CH4

MCF(S,k) = methane conversion factors for each manure management system S by climate region k, %

MS(T,s,k) = fraction of livestock category 7"s manure handled using manure management system S in climate region k, dimensionless

Even when the level of detail presented in the Tier 2 method is not possible in some countries, country-specific data elements such as animal mass, VS excretion, and others can be used to improve emission estimates. If country-specific data are available for only a portion of these variables, countries are encouraged to calculate country-specific emission factors, using the data in Tables 10A-4 through 10A-9 to fill gaps.

Measurement programs can be used to improve the basis for making the estimates. In particular, measurements of emissions from manure management systems under field conditions are useful to verify MCFs. Also, measurements of Bo from livestock in tropical regions and for varying diet regimens are needed to expand the representativeness of the default factors.

As emissions can vary significantly by region and livestock species/category, emission estimates should reflect as much as possible the diversity and range of animal populations and manure management practices between different regions within a country. This may require separate estimates to be developed for each region. Emission factors should be updated periodically to account for changes in manure characteristics and management practices. These revisions should be based on reliable scientifically reviewed data. Frequent monitoring is desirable to verify key model parameters and to track changing trends in the livestock industry.

VS excretion rates

Volatile solids (VS) are the organic material in livestock manure and consist of both biodegradable and nonbiodegradable fractions. The value needed for the Equation 10.23 is the total VS (both degradable and nonbiodegradable fractions) as excreted by each animal species since the Bo values are based on total VS entering the systems. The best way to obtain average daily VS excretion rates is to use data from nationally published sources. If average daily VS excretion rates are not available, country-specific VS excretion rates can be estimated from feed intake levels. Feed intake for cattle and buffalo can be estimated using the 'Enhanced' characterisation method described in Section 10.2. This will also ensure consistency in the data underlying the emissions estimates. For swine, country-specific swine production data may be required to estimate feed intake.

The VS content of manure equals the fraction of the diet consumed that is not digested and thus excreted as fecal material which, when combined with urinary excretions, constitutes manure. Countries should estimate gross energy (GE) intake (Section 10.2, Equation 10.16) and its fractional digestibility, DE, in the process of estimating enteric methane emissions.

Once these are estimated, the VS excretion rate is estimated as:

Equation 10.24 Volatile solid excretion rates

Where:

VS = volatile solid excretion per day on a dry-organic matter basis, kg VS day-1

GE = gross energy intake, MJ day-1

DE% = digestibility of the feed in percent (e.g. 60%)

(UE • GE) = urinary energy expressed as fraction of GE. Typically 0.04GE can be considered urinary energy excretion by most ruminants (reduce to 0.02 for ruminants fed with 85% or more grain in the diet or for swine). Use country-specific values where available.

ASH = the ash content of manure calculated as a fraction of the dry matter feed intake (e.g., 0.08 for cattle). Use country-specific values where available.

18.45 = conversion factor for dietary GE per kg of dry matter (MJ kg-1). This value is relatively constant across a wide range of forage and grain-based feeds commonly consumed by livestock.

Representative DE% values for various livestock categories are provided in Section 10.2, Table 10.2 of this report. The value for ash content fraction can range substantially between livestock types and should reflect national circumstances.

Bo values

The maximum methane-producing capacity of the manure (Bo) varies by species and diet. The preferred method to obtain Bo measurement values is to use data from country-specific published sources, measured with a standardised method. It is important to standardise the Bo measurement, including the method of sampling, and to confirm if the value is based on total as-excreted VS or biodegradable VS, since the Tier 2 calculation is based on total as-excreted VS. If country-specific Bo measurement values are not available, default values are provided in Tables 10A-4 through 10A-9.

MCFs

Default methane conversion factors (MCFs) are provided in Table 10.17 for different manure management systems and by annual average temperatures. MCFs are determined for a specific manure management system and represent the degree to which Bo is achieved. The amount of methane generated by a specific manure management system is affected by the extent of anaerobic conditions present, the temperature of the system, and the retention time of organic material in the system. Default MCF values for lagoons presented in Table 10.17 include the effect of longer retention times, and as a result, are higher than other systems under most circumstances.

Since liquid-based systems are very sensitive to temperature effects, where possible default MCF values for these systems have been presented in Table 10.17 for specific annual average temperatures in each climate range. While these temperature ranges should cover most climate conditions, areas that have extreme high or low annual average temperatures outside the 10 to 28 degree Celsius range should utilize the end-of-range (i.e., 10 or 28 degree) values or investigate developing country-specific values.

These default values may not encompass the potentially wide variation within the defined categories of management systems. Therefore, country-specific MCFs that reflect the specific management systems used in particular countries or regions should be developed if possible. This is particularly important for countries with large animal populations or with multiple climate regions. In such cases, and if possible, field measurements should be conducted for each climate region to replace the default MCF values. Measurements should include the following factors:

• Timing of storage/application;

• Feed and animal characteristics at the measurement site (see Section 10.2 for the type of data that would be pertinent);

• Manure characteristics (e.g., VS influent and effluent concentrations for liquid systems);

• Determination of the amount of manure left in the storage facility (methanogenic inoculum);

• Time and temperature distribution between indoor and outdoor storage;

• Daily temperature fluctuation; and

• Seasonal temperature variation.

Table 10.17

MCF VALUES BY TEMPERATURE FOR MANURE MANAGEMENT SYSTEMS

Systema

MCFs by average annual temperature (°C)

Source and comments

Cool

Temperate

Warm

< 10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

> 28

Pasture/Range/Paddock

1.0%

1.5%

2.0%

Judgement of IPCC Expert Group in combination with Hashimoto and Steed (1994).

Daily spread

0.1%

0.5%

1.0%

Hashimoto and Steed (1993).

Solid storage

2.0%

4.0%

5.0%

Judgement of IPCC Expert Group in combination with Amon et al. (2001), which shows emissions of approximately 2% in winter and 4% in summer. Warm climate is based on judgement of IPCC Expert Group and Amon et al. (1998).

Dry lot

1.0%

1.5%

2.0%

Judgement of IPCC Expert Group in combination with Hashimoto and Steed (1994).

Liquid/Slurry

With natural crust cover

10%

11%

13%

14%

15%

17%

18%

20%

22%

24%

26%

29%

31%

34%

37%

41%

44%

48%

50%

Judgement of IPCC Expert Group in combination with Mangino et al. (2001) and Sommer (2000). The estimated reduction due to the crust cover (40%) is an annual average value based on a limited data set and can be highly variable dependent on temperature, rainfall, and composition.

When slurry tanks are used as fed-batch storage/digesters, MCF should be calculated according to Formula 1.

Without natural crust cover

17%

19%

20%

22%

25%

27%

29%

32%

35%

39%

42%

46%

50%

55%

60%

65%

71%

78%

80%

Judgement of IPCC Expert Group in combination with Mangino et al. (2001). When slurry tanks are used as fed-batch storage/digesters, MCF should be calculated according to Formula 1.

Chapter 10: Emissions from Livestock and Manure Management

Table 1G.17 (continued)

MCF VALUES BY TEMPERATURE FOR MANURE MANAGEMENT SYSTEMS

Systema

MCFs by average annual temperature (°C)

Source and comments

Cool

Temperate

Warm

< 1G

11

12

13

14

15

16

17

18

19

2G

21

22

23

24

25

26

27

> 28

Uncovered anaerobic lagoon

66%

68%

70%

71%

73%

74%

75%

76%

77%

77%

78%

78%

78%

79%

79%

79%

79%

80%

80%

Judgement of IPCC Expert Group in combination with Mangino et al. (2001). Uncovered lagoon MCFs vary based on several factors, including temperature, retention time, and loss of volatile solids from the system (through removal of lagoon effluent and/or solids).

Pit storage below animal confinements

< 1 month

3%

3%

30%

Judgement of IPCC Expert Group in combination with Moller et al. (2004) and Zeeman (1994).

Note that the ambient temperature, not the stable temperature is to be used for determining the climatic conditions. When pits used as fed-batch storage/digesters, MCF should be calculated according to Formula 1.

> 1 month

17%

19%

20%

22%

25%

27%

29%

32%

35%

39%

42%

46%

50%

55%

60%

65%

71%

78%

80%

Judgement of IPCC Expert Group in combination with Mangino et al. (2001). Note that the ambient temperature, not the stable temperature is to be used for determining the climatic conditions. When pits used as fed-batch storage/digesters, MCF should be calculated according to Formula 1.

Table 10.17 (continued)

MCF VALUES BY TEMPERATURE FOR MANURE MANAGEMENT SYSTEMS

Systema

MCFs by average annual temperature (°C)

Source and comments

Cool

Temperate

Warm

< 10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

> 28

Anaerobic digester

0-100%

0-100%

0-100%

Should be subdivided in different categories, considering amount of recovery of the biogas, flaring of the biogas and storage after digestion. Calculation with Formula 1.

Burned for fuel

10%

10%

10%

Judgement of IPCC Expert Group in combination with Safley et al. (1992).

Cattle and Swine deep bedding

< 1 month

3%

3%

30%

Judgement of IPCC Expert Group in combination with Moller et al. (2004). Expect emissions to be similar, and possibly greater, than pit storage, depending on organic content and moisture content.

Cattle and Swine deep bedding (cont.)

> 1 month

H0/»

19%

20%

22%

25%

2y%

29%

32%

35%

39%

42%

46%

50%

55%

60%

65%

yl%

y 8%

80%

Judgement of IPCC Expert Group in combination with Mangino et al. (2001).

Composting - In-vesselb

0.5%

0.5%

0.5%

Judgement of IPCC Expert Group and Amon et al. (1998). MCFs are less than half of solid storage. Not temperature dependant.

Composting - Static pileb

0.5%

0.5%

0.5%

Judgement of IPCC Expert Group and Amon et al. (1998). MCFs are less than half of solid storage. Not temperature dependant.

Composting - Intensive windrowb

0.5%

1.0%

1.5%

Judgement of IPCC Expert Group and Amon et al. (1998). MCFs are slightly less than solid storage. Less temperature dependant.

Composting - Passive windrowb

0.5%

1.0%

1.5%

Judgement of IPCC Expert Group and Amon et al. (1998). MCFs are slightly less than solid storage. Less temperature dependant.

Chapter 10: Emissions from Livestock and Manure Management

Table 10.17 (continued) MCF values by temperature for manure management systems

System*

MCFs by average annual temperature (°C)

Source and comments

Cool

Temperate

Warm

< 10 11 12 13 14

15 16 17 18 19 20 21 22 23 24 25

26 27 > 28

Poultry manure with litter

1.5%

1.5%

1.5%

Judgement of IPCC Expert Group. MCFs are similar to sol id storage but with generally constant warm temperatures.

Poultry manure without litter

1.5%

1.5%

1.5%

Judgement of IPCC Expert Group. MCFs are similar to dry lot at a warm climate.

Aerobic treatment

0%

0%

0%

MCFs are near zero. Aerobic treatment can result in the accumulation of sludge which may be treated in other systems. Sludge requires removal and has large VS values. It is important to identify the next management process for the sludge and estimate the emissions from that management process if significant.

Formula 1 (Timeframe for inputs should reflect operating period of digester): MCF = [{CH4 prod - CH4 used - CH4 flared + (MCFstorage /100 * Bo * VSstorage * 0.67 )}/ (Bo* VSstorage * 0.67)] *100 Where:

CH4 prod = methane production in digester , (kg CH4) . Note: When a gas tight coverage of the storage for digested manure is used, the gas production of the storage should be included. CH4 used = amount of methane gas used for energy, (kg CH4) CH4 flared = amount of methane flared, (kg CH4)

MCFstorage = MCF for CH4 emitted during storage of digested manure (%) VSstorage = amount of VS excreted that goes to storage prior to digestion (kg VS)

When a gas tight storage is included: MCFstorage = 0 ; otherwise MCFstorage = MCF value for liquid storage

a Definitions for manure management systems are provided in Table 10. 18.

b Composting is the biological oxidation of a solid waste including manure usually with bedding or another organic carbon source typically at thermophilic temperatures produced by microbial heat production.

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