Methods for Disposal or Processing of Waste Streams from Intensive Livestock Production in Scotland and Northern Ireland

Technical Report - May 2005
Summary Report – June 2005 

Background to research

The Integrated Pollution Prevention and Control Directive requires that operators must:

The Directive covers a range of activities but most numerous in Northern Ireland are those for the intensive rearing of pigs and poultry. The greatest number of intensive livestock installations in Northern Ireland are involved in broiler production but there are also IPPC installations for egg production and pig rearing.  A similar situation exists in Scotland.

In general land spreading has been used as a key disposal route for livestock manures from these installations, although in Scotland most broiler litter is burned for energy production.  In Northern Ireland large quantities of broiler litter have been utilised in the production of mushroom compost.

Many freshwaters in Northern Ireland and some in Scotland are highly eutrophic and soils in many areas have high phosphate levels.  Producers will in some cases be constrained by the amount of land available for spreading and alternative techniques for dealing with livestock manures will need to be employed.

Objectives of research

Four key tasks/objectives were identified:

Task 1:  To characterise and quantify manure waste streams from intensive pig and poultry installations.  In order to define the extent of the problem, reliable information of the quantity and nutrient content of broiler litter, layer manure and pig slurry had to be established, and where appropriate recommendations for revision of standard figures made.

Task 2:  To review the environmental impact of current disposal practices, involving the identification of the key environmental issues and activity data for each current practice, including products arising from any down stream processing.

Task 3:  Prepare an inventory of past and current research and techniques employed in other countries in Europe and further afield, with a focus on successful techniques.

Task 4:  Identify alternative treatment method options with the greatest potential for Northern Ireland and Scotland, taking into account the structure of the sectors and environmental constraints in Northern Ireland   and Scotland.  Include economic and environmental aspects in the evaluation as well as the potential for disease dispersion.

Key findings and recommendations

Broiler litter

There was good evidence from the study that figures for nutrient output and quantity of broiler litter should be updated and a recommendation was made based of the data obtained from the study.  In Northern Ireland there is a real possibility that combustion as a biomass fuel can deal with surpluses in the medium term with appropriate investment in either a number of small combustion plants or a large centralised power generation plant.  A recommendation was made that combustion of broiler litter is adopted as an alternative utilisation for almost all surplus litter produced in Northern Ireland, as is currently the case in Scotland. Mushroom compost manufacture was also an important alternative utilisation route.

Layer manure

Clear differences from previous standard figures for nutrient content and quantity were not apparent, and no recommendation for change has been made.  Management options aimed at producing drier manure should be implemented, as this would permit a greater range of alternative uses.  Opportunities for composting should be actively pursued, but establishing markets for compost taking into account any legal constraints on the end use of the product would be a key element of this strategy.  A recommendation was also made that opportunities for development of manure into a more saleable product are pursued, e.g. by pelletising and selling into value added markets outwith traditional agriculture.

Pig manure and slurry

There was significant variation in nutrient content of pig manure and no recommendation was made for changes to standard figures.  As a result of IPPC, changes are currently being made to pig diets to reduce the nitrogen and phosphorus content of manures and slurry.  A recommendation was made that more detailed studies of this aspect be undertaken in two or three years time to evaluate this benefit.  A recommendation was made that best management practice and techniques such as solids liquid separation of slurries be implemented.  Further reductions in phosphorus are possible as shown by the results from multi-stage processes, and more novel processing techniques such as phosphorus removal by precipitation should be further examined.

Key words: Integrated pollution prevention and control; IPPC; pig; poultry; manure; broiler litter; slurry; disposal; alternative; utilisation; combustion; composting; biofuel; environmental; aspect; impact; intensive livestock production; land spreading; land bank; nitrogen; phosphorus; nutrients; eutrophication

 Copies of the two reports are available in hard copy:

Technical Report UKPIR01/TR at 25.00

Summary Report UKPIR01/SR at 10.00

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