Resources consumption add up to around 68 billion tons of materials per year, meaning a consumption ten times higher globally than in 1902. Driven by this fact and a number of challenges such as climate change and expanding populations, the development of a so-called “bioeconomy”, which drives closing the loop of nutrients like nitrogen, phosphorus and potassium as well as raw materials, is becoming increasingly important.

In this context, the European Commission drafted an ambitious strategy for recycling management at the end of 2015, in which the waste of each economic sector plays an important role. A residue-based bio-economy will contribute to environmental sustainability and it will provide investment opportunities with respect to waste industry markets.

The resources of industrial and municipal wastewater, including digestate from biogas and sewage sludge, are substantial and could drive a long-term strategic paradigm shift towards a bio-based economy. Due to the depletion of non-renewable mineral resources (e.g. phosphorus) and the increase in production costs (e.g. nitrogen fertilizers), the focus of research and development has shifted from disposal and treatment to the recovery of resources.

Technologies such as membrane distillation, to which the current issue of “nachhaltige technologien” is dedicated, are currently of interest for further development. The various examples in the articles show the diversity of the technology, but also demonstrate what challenges need to be solved.