Characteristics of anaerobic-digested manure Anaerobic digestion: A way to enhance nutritional performance of animal manure Torben Ravn Pedersen National.

Characteristics of anaerobic-digested manureAnaerobic digestion: A way to enhance

nutritional performance of animal manure

Torben Ravn PedersenNational SpecialistBiogas and Slurry Separation

Subejcts

• Danish Agricultural Advisory Service

• Manure handling in Denmark

• Biogas in Denmark

• Nutritient value in treated manure

Danish Agricultural Advisory Service

Manure types in Denmark

79%

5%

5%

11%

Slurry

Urine

Farm yard manure

Deep litter

How is slurry spread in Denmark?

0%

68%

32%

Broadspreading

Trailing hoses

Direct injection

About 60 farmscale biogas plants in Denmark

20 centralized biogas plants

Biogas rests on tree legs

Biogas

Energy EnvironmentAgriculture

Agricultural advantages

• Improved fertilizer value of nitrogen

• Balanced P and K-balance in slurry

• Homogeneous and light fluid

• Full declaration of nutrients

• Bacteria-free and seedless

• Reduced costs for transportation of slurry

Environmental advantages

• Reduced nitrate leaching

• Reduced odour problems

• Reduced green house gas emission

• Controlled recycling of organic waste (turns waste into valuable fertilizer)

Mixing and digesting slurry change the characteristic of

the slurryDM,

%

N-tot,

kg/t

NH4-N,

kg/t

P,

kg/t

K,

kg/t

pH NH4-N, %

Digested slurry

Pig slurry

Cattle slurry

4,8

5,0

7,5

4,4

4,8

3,9

3,5

2,9

2,4

1,0

1,1

0,9

2,3

2,3

3,5

7,6

7,1

6,9

81

74

61

Ammonia evaporation in spring barley

0

10

20

30

40

50

2002 2003

NH

3-lo

ss, %

of s

prea

d N

H4-N

Untreated pig slurry Digested pig slurry

Improved fertilizer effect of nitrogen- trials in winter wheat

0 20 40 60 80 100

Cattle slurry, injected

Pig slurry, injected

Digested slurry, injected

Cattle slurry, trailing hoses

Pig slurry, trailing hoses

Digested slurry, trailing hoses

N-utilization, % (fertilizer equivalent)

Fertilizer value

Fertilizer plan for nitrogen for 1 ha grass

250250N-requirement, kg

170170N in slurry, kg total

6040N-utilization, %

10268N- in slurry, utilized, kg

34

27

-

-

Saved, kg

Saved, Euro

148182Mineral fertilizer

Digested slurryCattle slurry

Per hectare

N, P, and K in mineral fertilizer

0

20

40

60

80

100

120

140

160

1930 1940 1950 1960 1970 1980 1990 2000 2010

Kg

per

hec

tare

NPK

Pro

gno

sis

N-application in Denmark

0

50

100

150

200

250

300

350

400

450

1940 1950 1960 1970 1980 1990 2000 2010

1,00

0 to

nne

of N

per

yea

r

FertilizerManure

Injection in bare soil

Injection of slurry in grass

Digested slurry is low on bacteria

<5<5<5<5<5

1,300,000140,000690,000

9,000,00062,000

Mar. 18May 13July 15Sept. 9Nov. 11

AfterBeforeDate

Test results from Ribe Biogas,bacteria per ml. slurry (1998)

Log 1

0 ge

rms

per

ml.

slur

ry

Time, weeks

Slurry tank, 6-8°C Mesofile biogas, 35°CThermofile biogas, 53°C

10

6

5

3

Digestion reduces odour

Slurry separation –on treated manure

Fot

o:

Wes

tfal

ia

Fot

o:

Big

ada

n A

/S.

Thank you for your attention!