| abstract |
The invention is directed to the manufacture of fertilizer having commercial levels of nitrogen supplemented with organic substances, e.g., 16-0.5-2-17-3-14 (N-P- K-S-Fe-Organic by dry weight). The process causes treatment of organic matter with concentrated acid that heats a fertilizer mix causing the hydrolysis of various organic polymers that may be present. A biosolids mix is subsequently injected sequentially with a nitrogen base under controlled conditions. The resultant sterilized and liquefied organic matter is then disbursed over recycled material for the production of granules in a granulator before final drying to greater than 98 percent solids. Because the process allows for the controlled addition of acids and ammonia, desired levels of components can be achieved. For example, fertilizers with high nitrogen content can contain variable amounts of phosphate or iron. In addition, the process is both scalable, odor controlled and safe thereby allowing for the location of biosolid processing facilities in most any location desired without affecting the environment or generating a nuisance to local communities. Further, the fertilizer of the invention provides a dual nitrogen-release profile when applied to crops. After application to soil, fertilizer of the invention releases an immediate bolus of nitrogen, similar to traditional ammonium sulfate, which is followed by a continued slow release of nitrogen typically over a single growing season. |