Phosphorus is an essential nutrient for humans and nature. Phosphor cannot be replaced by other substances. Since 2006 it is forbidden spreading sewage sludge on the fields. New ways to use phosphorus from sewage sludge must be found.
Natural phosphorus reserves of high quality are limited and the global demand cannot be satisfied in the nearer future.
Switzerland has no natural resources for phosphorus, therefor the demand for agricultural applications are imported. Therefor recycling of fertilizer and crop residues are an important factor.
Detailed information about the project can be found in the project papers, periodically published by AWEL, Zurich Cantonal Agency of Waste, Water, Energy and Air (German/French editions only).