Vries et al 2011. LCA Pilots Mineralenconcentraten Final (3)x

SummaryIn 2009 and 2010, two Dutch ministries (Economic Affairs, Agriculture and Innovation, andInfrastructure and the Environment) and the agricultural industry in the Netherlands carried out a pilotproject with approval of the European Commission. The aim of the project was to study theagricultural, economic and environmental effects of producing and using mineral concentrates fromanimal slurry as a replacement for mineral fertilizer. Eight pilot facilities producing the mineralconcentrate were set up and studied, and four sub-studies investigated aspects of the production anduse of their products. One study assessed the environmental consequences by means of Life CycleAssessment (LCA). This report describes its findings.During the life cycle of mineral concentrates (i.e. from their production until their application),emissions of pollutants such as greenhouse gases and ammonia occur. Additionally, fossil energy isused for processing and for processes such as transportation and application of the end product. Littleis known about how these emissions and uses change if mineral concentrate and other end products(solid fraction, permeate, and concentrate from ultrafiltration) are applied in agriculture instead ofslurry and mineral fertilizer. The LCA therefore aimed to provide insight into the change of theenvironmental impact by comparing the production and application of the end products from the pilotfacilities, combined with application of animal slurry and mineral fertilizer, with application of onlyanimal slurry and mineral fertilizer (i.e. current practice). To express the environmental impact, fiveenvironmental indicators were used: greenhouse gas emission, ammonia emission, nitrate leaching,particulate matter emission, and fossil energy use. Phosphate leaching and depletion was notconsidered as it was expected to be similar for both situations.To assess all changes in the environmental impact related to the production and use of the endproducts from the pilot facilities, all products were included in the system examined (consequentialapproach to LCA). A cradle to grave approach was used, i.e. the system was defined as includingeverything from the slurry storage (after excretion) until the final distribution and application of slurryand its end products. Four distribution routes and application areas were considered: local applicationon an arable or dairy farm (arable land), local application on dairy farm (grassland), application on anarable farm elsewhere in the Netherlands, and application on an arable farm outside the Netherlands.Four scenarios were used to assess the change in environmental impact. Three scenarios were forfattening pig slurry and one was for dairy cattle slurry. The results from the scenarios were comparedto a reference for both slurry types reflecting current agricultural practice. To make the comparison, afunctional unit (FU) of 1 ton slurry with the same composition was used. The scenarios for fattening pigslurry were:scenario 1 (Sc1V):scenario 2 (Sc2V):scenario 3 (Sc3V):The scenario for dairy cattle slurry was:scenario 1 (Sc1R):processing the surplus of slurry in a cooperative plant by means ofmechanical separation, flotation, and reverse osmosis. After processing, theend products were distributed and applied.the same as in Sc1V but including anaerobic digestion of the solid fraction(remaining after liquid separation).processing the surplus of slurry in a cooperative plant by decanting (orcentrifugation), ultrafiltration, and reverse osmosis. In addition, the solidfraction and concentrate from ultrafiltration were anaerobically digested.anaerobic digestion of all the slurry, and processing the surplus ofdigestate (the material remaining after digestion) by means of:decanting, ultrafiltration, and reverse osmosis. The processingwas on-farm.Crucial to any LCA because they affect the outcome of the study are the chosen system boundariesand the underlying assumptions. The boundaries and assumptions in this LCA were based ondiscussions within the project group and with external experts, and on the literature. The mainassumptions relating to the distribution and application of the end products investigated were:fattening pig slurry is applied only on arable land, whereas dairy cattle slurry is applied on grasslandand arable land. It was assumed that the demand for nitrogen (N), phosphorus (P 2 O 5 ) and potassium(K 2 O) at every application area was identical in the references and the scenarios. In each applicationarea the maximum legally permitted amounts of N and P 2 O 5 from animal slurry applied. It waspermissible to apply mineral concentrate over and above the limit for animal slurry, but the permissible