Nitrogen and phosphorus, which are necessary for agriculture, today depend in an alarming way on massively imported fossil resources. In addition to the impact on aquatic environments and the climate, this is an enormous and little-known threat to the sustainability of our food supply.

Separate collection of urine to recycle it into fertilizers is likely to meet these challenges, provided that food and sanitation systems (r)evolution takes place, without neglecting societal acceptability. This perspective implies redesigning urban sanitation and its link to rural areas. Throughout the world, in France, and now in the Paris Region, players are committed to this approach.