A WIT Press publication. The prevailing large-scale use of chemical fertilizers has been affecting environmental degradation. a broken nutrient cycle has caused problems worldwide, which are related to the question of how to feed 9 billion people by 2050 while limiting human operations within the planetary boundaries. Indispensable nutrients, phosphorus (P) and nitrogen (N), often leak because of human activities, such as food production. efficient nutrient recycling can alleviate the problem.

There is a need to find new and sustainable nutrient sources for organic farming. Urban (food) waste can be a highly valuable source with low environmental impact and high recycling efficiency. This source can be used to compensate for the negative nutrient balances in organic farming. However, it must be treated to become hygienic, biologically stable, and easy to handle. Solution Anaerobic digestion of food and organic waste in a closed system produces fertiliser (digestates) and energy while avoiding greenhouse gas (GHG) emission.