Waste legislation at national and EU level is facing major changes in the coming years. New legislative and non-legislative instruments aim not only to reduce the amount of waste generated but also to improve the recycling of waste generated. Since the instruments include increases in waste fees, there is also a clear economic rationale for new innovations that increase waste recovery. On the other hand, the new legislation also introduces a landfill ban on organic waste, which directly imposes a requirement to find recovery for organic waste. The objective of the project described here is to find out whether the recycling of biosludge and bio ash produced in the Rovaniemi region could provide fertilisers tailored to different sites. By combining biosludge (hygienised sewage treatment plant sludge) and ash in different proportions, the resulting product’s nutrient composition can be adapted not only for forestry (different composition of mineral and peat soils) but also for agriculture and horticulture. The effects of fertilisers are studied by fertilising mineral and peat soils with various combinations of ash and biosludge, comparing the growth of the trees of fertilised sites and possible changes in soil and land water with non-fertilised and commercial fertilisers. The use of other industrial by-streams (e.g. slag and/or fibre sludge (zero-fibre)) to improve the properties of fertilisers will also be studied in a smaller scale (nature level) as well as in the laboratory. For example, in the RAE project of the University of Oulu, slag has been found to increase the mechanical stability of ash granules. Potential environmental impacts will also be measured by collecting collection products (berries or mushrooms according to occurrence) from the test areas to measure the concentrations of heavy metals. The project will result in recommendations on the composition and quantity of bio-ash-based fertilisers for forests in the fabric and peatlands. The development of fertilisers is carried out in cooperation with companies producing these secondary streams in Rovaniemi (Napapiirin Energia and Vesi Oy, Rovaniemi Development and Napapiirin Residuum Oy).
