As part of the programme for development of cleaner products, the Danish Environmental Protection Agency under the Danish Ministry of Environment has financed the project: Development of Methods for Utilisation of Animal Waste in Biogas Plants and Extraction of Phosphorus from Incineration of Meat and Bone Meal. The project reference number is M 3288-0008. The project report is written in Danish.

The project was carried out by COWI (consulting engineers) in collaboration with SFI (Danish Meat Research Institute), EnergiGruppen Jylland (municipal works) and P.E. Consult (phosphorus chemistry).

With background in the conditions in Denmark, the present report maps the amounts of animal by-products of various origin and category, with data characteristics of the different waste types in relation to European Community Regulation 1774/2002 (health rules concerning animal by-products not intended for human consumption). The report describes different ways of treating this waste, e.g. biological treatment in biogas plants, rendering, incineration, co-incineration and use of phosphorus from ash as feedstock for production of artificial fertilisers.

The report anticipates improved work flow and sorting at the abattoirs. Possible methods of disposal have been evaluated, among these the questions of fractions and how much can be used in biogas plants have been considered. The biogas route has been investigated in depth, supported by tests of co-fermentation of meat pulp together with manure and other organic industrial wastes. The report also describes how to deal with possible problems that may occur if too much meat pulp is added to biogas plants.

Besides investigating the material that can be added to biogas plants, it has been investigated how ashes from incineration of bones from pigs can be used as phosphorus feedstock in the production of artificial fertiliser.

In Denmark, the annual meat production presently amounts to about 24 million pigs and 0.6 million cattle. The total amount of waste covered by the EU Regulation 1774/2004 is about 1 million tonnes per year.

The main conclusion is that with a better sorting of the waste, it is possible to find suitable disposal routes for the waste generated in Denmark, and, further, that:

• It is possible to use the resources in the animal waste.
• The fat content is important, especially for use in biogas plants.
• The use in biogas plants requires precision in relation to dosing and monitoring.
• Phosphorus in ashes from incineration of bone meal can technically be used as feedstock for production of artificial fertiliser.

The project suggests the following prioritisation in the disposal of animal waste:

• Sterilised Category 3 material for pet food and added to fodder for breeding furred animals. Sterilised blood meal from non-ruminant animals can be used as fodder at fish farms.
• Sterilised Category 2 poultry material can be added to fodder for breeding furred animals.

• Hygienised flotation sludge for biogas plants.
• Sterilised meat pulp from pork and poultry, including dead pigs, to biogas plants (normally max. about 3% of total added material).
• Hygienised fish and dairy material to biogas plants.
• Category 2 manure material to biogas or direct use on fields.

• Specified Risk Material (SRM) as meat and bone meal to cement industry.
• Dedicated incineration of Category 1 and 2 materials with controlled disposal of ashes.
• Category 2 bone meal to be incinerated at natural gas fired power plants approved for waste incineration with re-incineration of milled bottom ash. Energy used for combined heat and power production.
• Category 2 meat and bone meal for co-incineration of waste incineration plants with controlled disposal of the ashes.
• Incineration of technical fat for energy production in environmentally approved plants or use as feedstock in the production of bio-diesel.