1. Anaerobic digestion of slaughterhouse waste in Sweden
Åke Nordberg
JTI - Swedish Institute of Agricultural and Environmental Engineering

2. Anaerobic digestion of animal by-products:
a sustainable treatment alternative
Biogas

3. Presentation out-line
Regulations for anaerobic digestion (AD) of animal by-products (ABP)
Potential biogas substrates from slaughtered animals
AD of slaughterhouse waste in Sweden

4. Regulation (EC) No 1774/2002, applicable from 1st of May 2003 in all member states
Category
Material
Category 1
Specified Risk Material representing an increased risk for public health, animals and environment.
Not designated for AD
Category 2 – without preliminary treatment
Manure, digestive tract content, milk, colostrum
Category 2 – after sterilisation with steam pressure and marking (with smell)
Fallen animals, slaughtered but not intended for human consumption (everything not included in Category 1 and 3)
Category 3 – approved according to Article 15
(pasteurisation)
Material originating from animals fit for slaughter but not intended for human consumption. ABP from food production
Category 3 – approved according to national legislation
Catering waste (except from international transport)

5. Pig slaughtering facility
Manure
Cat. 2 – no required treatment
Anaerobic
Digester
(According to
article 15)
Digestive tract content
Digestive tract
Cat. 3 - pasteurisation
Pasteurisation
<12 mm
≥60 min
≥70 °C
Bones, slaughter by-products
Parts of slaughtered animals
Blood
Sterilisation
≥ 133 °C
≥ 3 bar
≥ 20 min
Cat. 2 - sterilisation
Fallen animals
Screenings and
flotation sludge >6 mm
(< 6 mm not covered by
ABP-regulation)
End product
Salmonella: 0 CFU in 25 g (5 samples)
Enterobacteriaceae: 3 samples < 10 CFU/g, 2 samples < 300 CFU/g
Placing on the market, trade, application to land (not pasture)

6. Bovine slaughtering facility
Manure
Cat. 2 – no required treatment
Anaerobic
Digester
(According to
article 15)
Rumen content
Rumen
Cat. 3 - pasteurisation
Pasteurisation
<12 mm
≥60 min
≥70 °C
Bones, slaughter by-products
Parts of slaughtered animals
Blood*
(no SRM in blood stream)
SRM; vertebral column
and skull, intestines
Sterilisation/
Incineration
Not intended for AD
Cat. 1
Screenings and
flotation sludge >6 mm
End product
Salmonella: 0 CFU in 25 g (5 samples)
Enterobacteriaceae: 3 samples < 10 CFU/g, 2 samples < 300 CFU/g
Placing on the market, trade, application to land (not pasture)
(< 6 mm not covered by
ABP-regulation)

7. Calculated methane potential from slaughter of cattle and pigs divided into different waste categories (% of total methane potential) and the total amount (MJ or kWh per animal).
Rumen,
stomach
and
intestinal
content
(Cat. 2)
Cat. 3
(excl. blood)
Blood
(cat. 3)
Cat. 2
Cat. 1
(SRM)
Total
% of tot
MJ/
animal
kWh/
Cattle 9 62 5 3 21
1300
361
Pig 6 82 8 4 -
140 39

8. Potential value of gas and organic fertiliser from slaughterhouse
Euro/ton
Fertiliser
Meat and bone fraction 65 18
Blood 10 4
Digestive tract +content 11 2
Sludge 22 5
Raw biogas: 3.3 Eurocent/kWh
N: Euro/kg
P: Euro/kg
K: Euro/kg

9. Slaughterhouse waste in Sweden- legislation background
1988 (SFS 1988:537)
Meat meal from carcasses not allowed in animal fodder
1991 (LSFS 1990:51)
Use of low-risk animal by-products in ruminant fodder prohibited in 1991

10. Existing biogas plants approved for ABP co-digestion
Luleå
Skövde
Borås

11. Swedish co-digestion plants treating animal by-products
Temperature
Digestate
Gas utilisation
Helsingborg
Mesophilic
Slurry organic fertiliser
Heat, electricity, vehicle fuel
Kalmar
Thermophilic
Vehicle fuel
Kristianstad
Heat, vehicle fuel
Laholm
Upgraded gas to grid
Linköping
Uppsala
Vänersborg
Solid digestate
Skövde
Borås
Luleå
Heat, electricity

12. Summary of capacity and treated waste in Swedish biogas plants* 2003
Treatment capacity m3
100 %
Used capacity m3
73 %
Planned increase of treatment capacity m3
+42 %
Manure m3
30%
Source-sorted household waste m3
5 %
Source-sorted from restaurants, shops etc
2 200 m3
1 %
Slaughterhouse waste m3
45 %
Waste from other food industry m3
12 %
Other organic waste
6 000 m3
3 %
Water
7 500 m3
Total amount of substrate m3
*10 ABP-approved biogas plants (Major part treated in 7 plants)

13. Concluding remarks
Animal by-products are suitable for anaerobic digestion giving high gas yields and a nutrient rich organic fertilizer
AD of slaughterhouse waste within the legislative framework 1774/2002 offers a safe and sustainable waste management solution
Governmental subsidies for facilitating investments in AD of slaughterhouse waste is well invested money from a sustainable point of view