Environmentally friendly use of non-coal ashes in Sweden

The Swedish Thermal Engineering Research Institute (Värmeforsk) initiated an applied research program “Environmentally friendly use of non-coal ashes”, in 2002. The program aims at increasing knowledge on the by-products of energy production and their application. The goal of formulating technical and environmental guidelines and assessments is a major point of the program, which is supported by about forty authorities and private organisations. The programme has been divided into four areas: recycling of ashes to forests, geotechnical applications, use in landfilling, and environmental aspects and chemistry. Among all results obtained, the following progress is shown: • Evidence for the positive effects of spreading ashes on forest growth. • A proposal for environmental guidelines on the utilisation of ashes in construction. • A handbook for using non-coal fly ashes in unpaved roads. • Technical and environmental assessments of MSWI bottom ashes in road construction. • Development of the use of ashes with municipal wastewater sludge as a cover for landfills and mine tailings. • Use of ashes from bio-fuels in concrete and replacement of cement in stoop mining. • A method to classify those by-products from combustion that have mirror entries in the EWC as a hazardous or non-hazardous compound. The Ash Programme has also made it possible to increase knowledge on ashes as valuable materials, on quality assurance and on markets for recovered materials.