Background The capacity of landfill sites to receive waste remains limited and new ways must be found to reuse waste. While cleaned and recycled soil material can be valuable for agricultural and geo-engineering (e.g. road construction) applications, its acceptance needs to be better established. In Europe, around 18 million tonnes of foundry waste sand is produced every year and even large landfill sites often have insufficient capacity to accept it. In most countries, several smaller landfills are being closed and replaced by large ‘EU landfills’. However, the distances and transport costs to these sites are increasing for foundry companies and alternative means of treating these wastes in a more environmental friendly way are being sought. Objectives The LIFE-FOUNDRYSAND project aims to promote sustainable production, waste prevention and recycling by piloting new, innovative biological methods of cleaning different foundry waste sand types and eliminating hazardous organic trace contaminants. The objective is to study the quality of the piloted samples and ensure that they fulfil the product requirements for the reuse of cleaned sand as a substitute for ground construction materials or other soil-like materials for agricultural and geo-engineering applications. The specific objectives are to: Develop a new method for cleaning and reusing foundry waste sand through composting; Create a compost from foundry waste sand mixed with other biowaste (household waste, sludge and the waste from the food, wood and paper industries) and demonstrate the microbiological degradation processes in open heaps; Compare the microbiological degradation in covered landfills with the project’s system; Verify compost quality and applicability in different fields of application (gardening, green fields, ground construction, etc.); Produce guidelines for foundries and suppliers of cleaning service in Europe; Implement the procedure in foundries to minimise their waste, reduce their operational costs and increase their energy saving; Reduce the amount of contaminated material entering landfill sites; Improve the use and acceptance of this valuable material (the cleaned foundry waste sand) for agricultural and geo-engineering applications. In areas with low humus content in soils, an artificial layer can be created in order to improve fertility, and to substitute for synthetic fertilisers; and Transfer this sustainable methodology to the 4000 plus foundries in Europe. By 2020, an estimated 200 foundries will be applying this new method, and by 2025, this figure will have increased to 1000. Expected results: New composting method developed for cleaning foundry waste sand; Around 500-600 tonnes of foundry waste sand cleaned at pilot composting facilities in Finland and Spain; Feasibility and cost-effectiveness of the new method calculated for Finland, Germany and Spain as pilot countries; Hazardous organic compounds (such as phenols, PAHs) cleaned with an efficiency of more than 95%. The final composted product will meet the national requirements for such materials; Reduction of methane emissions in comparison with landfilling; and CO2 equivalent emissions reduced by more than 80%.