Research Presented on Alternative Uses for Pig Manure
A crowd of over 100 people attended a research dissemination day at Teagasc Moorepark, on possible alternative uses for pig manure. The event was the culmination of a Department of Agriculture funded project on alternative uses for pig manure. Personnel from Teagasc, NUI Galway, AFBI Northern Ireland, Waterford Institute of Technology and the University of Limerick presented their findings from the three year research project. Pilot-scale demonstrations on the different technologies were accompanied by short presentations from the project team. The technologies included anaerobic digestion, separation of pig manure, composting, use of pig manure as a solid biofuel, the use of integrated constructed wetlands and woodchip filters, and bio-safety aspects of manure treatments.
Increasing the amount of energy produced from renewable sources is a stated objective of the European Union. Anaerobic digestion, investigated in this project, can extract energy from animal and plant biomass, while still retaining the nutritive value of the material as a fertilizer. By capturing the methane during anaerobic digestion the project looked at reducing greenhouse gas emissions from stored pig manure. The project also examined the separation of pig manure into solid and liquid fractions, to explore the potential of the solid fraction as compost and/or fuel source and to treat the liquid fraction by means of woodchip filters and integrated constructed wetlands.
Tereza Cota-Nolan, Teagasc Moorepark presented the economics of each technology studied, and Dr. Peadar Lawlor, Teagasc Moorepark chaired a lively panel discussion at the end of the meeting. Dr. Lawlor stated that “while the cost analysis presented showed that the technologies investigated are not currently cost effective, they may have future potential”. For example, anaerobic digestion could be cost effective on large units (2000 sows plus), or if centralised treatment plants were developed and if the renewable feed-in tariff for energy sold to the grid was increased.
Pig manure has a significant fertilizer value (€6.13 per m3 or €28 per 1,000 gallons), as evident on the board prepared by Gerard McCutcheon, Teagasc Oak Park.
Dr. Lawlor said: “While the research showed the technologies on display may all have potential, the ultimate home for the nutrients in the manure (whether treated or untreated) was on land to supply nutrients for crop growth. The application of untreated pig manure on land is the most cost effective method of using pig manure in Ireland for the foreseeable future”.