In a unique project, raw material owners, converters, customers, universities and authorities are working together to utilise forest resources, close loops and reduce the use of non-renewable resources. The nutrients and minerals absorbed by trees as they grow accumulate in sludge and ash at pulp mills. Today, acidification is counteracted by ash recycling and the forest is fertilised with mineral fertilisers. To reduce the use of fossil raw materials, the loop should be closed and sludge and ash should be seen as useful resources. By processing the sludge into hydrocarbon and mixing it with biofuel ash, a new product is created that can both fertilise and alkalise forest land or be used as a plant medium and nutrient in forestry nurseries. With the applied project we want to develop technology and investigate environmental effects in soil and forestry nurseries. What opportunities and obstacles exist before the product can be used on a large scale. And whether there are business opportunities when residual products are recycled and the loop is closed.