A new perspective on sludge management - cross disciplinary enhancement of hybrid life cycle risk assessment (LiCRA)

Research Project, 2013 – 2016

Sewage sludge management is a significant challenge and a significant opportunity in Sweden. Returning the various nutrients in sludge to agriculture is limited in part by the different frames of reference and information tools on which the advocates and opponents of sludge rely. When quantitative risk assessments (QRA) are performed in relation to plans for supplying nutrients in agriculture, analysts typically provide a detailed assessment of the local risks. Consequently, the avoided risks associated with more energy intense options for sludge management are not considered. When life cycle assessment (LCA) of alternative sludge treatment options is performed, analysts usually consider a wide range of potential impacts, but do not model the land application in any detail. This project will provide a more holistic account of the risks of using sewage sludge in agriculture and energy production by making QRA more meaningful. This means taking the bigger picture into account rather than just focusing on a subset of chemical or microbiological emissions at the boundary of regulatory compliance. LCA can offer this larger perspective; however, the project aims to make sludge LCAs more accurate by including detailed QRA results in the indicators it uses to examine global environmental issues. The disparate origins of the two methods make hybridization a worthwhile research frontier with the potential to cast new light the sludge management challenge in Sweden and abroad.