Granulated organic and mineral fertilizers: Technology and utility properties

This work presents the selected aspects of a technological concept for the production of organic and mineral fertilizers from communal sludge stabilized with volatile ash, by using two methods of granulation: coating and pressure. The presented concept is the effect of optimization, taking into account an interference of a number of factors exerted onto the fertilizing values and the mechanical strength of the final products. The fertilizers (contain ash from brown coal) obtained according to that method are characterized by a sufficient (according to law) content of organic matter (35,73% w/w), total nitrogen (1,70% w/w), phosphorus P₂ O₅ (3,62% w/w) and after the modification, also potassium K₂O (8,43% w/w). The mechanical properties are better for the granulates, prepared by using pressure granulation (15,1 kG/cm²) and allow for their transportation, storage and application.