Uranium in Secondary Phosphate Fertilizers and Base Substrates from Water Treatment Plants
As a limiting factor for plant growth the demand for phosphorous (P) fertilizers is huge while the global phosphate reserves are strongly limited. Thus, the recycling of P from secondary raw materials such as sewage sludges and ashes or other organic waste materials will be a more and more important resource. In fertilizers, both primary and secondary, not only the nutrients but also the content of pollutants is important for an application in agriculture. Mineral P fertilizers may contain remarkable concentrations of uranium (U), cadmium (Cd) and other trace elements depending on their origin and chemical treatment.