The air consists of about 78% nitrogen (N2). With electricity, this element can be converted to nitrate (NO3), and after treatment with clean water (H2O), mainly nitric acid (HNO3) is left. This element can be used as fertilizer in tomato cultivation, for example, according to a study by the Business Unit Greenhouse Horticulture and Flower Bulbs of Wageningen University & Research. A subsequent study will examine whether this process is also possible with treatment of drain water.
The Dutch company VitalFluid developed a fertilization method based on this chemical principle. WUR investigated whether the fertilizers can be used for 'organic' cultivation (USDA approved). In fact, hardly any directly absorbable nitrogen fertilizers are allowed in this cultivation strategy. The organic fertilizers that are allowed are only available when they have been converted by micro-organisms in the growing media. As a result, growers cannot apply the fertilizers very precisely.
The research showed that the fertilizers created in the VitalFluid system can be directly absorbed by the crop. The tomato crop grew well; in the reference crop there were problems with the biological conversion of nitrogen. Moreover, it turned out that all drain water could be reused. Another advantage of the VitalFluid system is that it is expected to be more energy efficient in the long run than the production of other nitrate fertilizers: this requires natural gas for both the energy and the chemical process.
In the coming year, WUR will investigate whether the VitalFluid system is also feasible as green fertilization in conventional crops, by treating drain water. WUR is investigating whether the chemical process kills pathogens in the water and whether the crop's resilience is increased by the new fertilization.
The completed project was funded by the EU Horizon 2020 research and innovation program under Grant Agreement number 5049-1.