ABSTRACT
The content of this chapter symbolically closes the process of biomass production and use. Referring to the circulation of matter in nature, its aim is to show the full potential of biomass at a stage which, in conventional management, would mean waste. In the context of the circular bioeconomy, by contrast, it is something of value, necessary for further biomass production. The chapter therefore starts with a presentation of the concept of the natural recycling of biomatter (a form of ‘waste’) as nutrients and how those nutrients are turned into fertilisers. This naturally occurring or controlled process is placed within the legal and institutional framework, relating, inter alia, to the definition and status of ‘waste’. These conditions differ between individual EU member states, a subject which is also addressed in this chapter. The use of biowaste for further biomass production or remediation has significant economic, social and environmental impacts, which are also discussed. In the final part of the chapter, the authors present the results of their own experiments in the form of case studies of mixtures of sewage sludge and cellulose waste, and of biomass ash with sewage sludge, as soil improvers.
