Stikstof : Whitepaper Circulaire Meststoffen voor de Glastuinbouw

Samenvatting

This white paper is one of a three-part series of white papers developed with the Club of 100, in which the requirements and options of circular fertilisers for greenhouse horticulture are explored. In this report, we look at nitrogen, which is currently fixed from air through the Haber-Bosch process, using natural gas. There are more sustainable alternatives to produce nitrogen fertiliser, both using fixation and side-streams. We start with an comparative inventory of side-streams in the Netherlands, concluding that not enough nitrogen is available to cover demand of synthetic nitrogen fertiliser for both greenhouse horticulture and arable farming. Next, technologies are compared, in terms of energy consumption but also qualitative factors. These technologies can (1) fixate nitrogen from the air, (2) recover nitrogen from side-streams and (3) convert ammonium to nitrate, since nitrate is used in much higher amounts than ammonium in greenhouse horticulture. Lastly, this white paper presents contaminant limits, per g nitrogen, which manufacturers of circular fertilisers can use to better rule out risks in the cultivation system and beyond.