Solar and UV Treatment of Human Waste to Yield NPK Plant Fertilizer

Various methods of removal of unwanted substances in human urine as applied to agriculture are examined. The current production processes of nitrogen and potassium for crop fertilizers are notably environmentally taxing. Phosphorus is primarily obtained through mining and will eventually run out. Human urine is abundant, renewable, and contains high concentrations of urea, phosphate, and potassium, all of which are excellent plant fertilizers. Human urine often contains pathogens, particularly if stored for long periods, as well as pharmaceuticals and their metabolites. This investigation covers various methods to degrade pathogens and large organic molecules in urine while maintaining high concentrations of fertilizer compounds. Methods include high temperature and pressure treatments, UV exposure, UV exposure with a TiO₂ catalyst, and absorption into activated carbon.