Modifications of Concentrations of Plant Macronutrient Ions in Digestate from Anaerobic Digestion during Nitrification Processes

The goal of this study was to establish a system for converting digestate from anaerobic digestion processes into liquid fertilizer for soilless culture. Modifications of concentrations of plant macronutrient ions during nitrification processes were investigated with digestate from a simulated municipal organic waste. Concentrations of phosphate and calcium ions in the nitrified digestate increased; the rates of increase were 15.3 mg L–1 d–1 and 17.6 mg L–1 d–1, respectively. Moreover, concentrations of macronutrient ions, except for magnesium, in the nitrified digestate were similar to those in a standard nutrient solution that is commonly applied to soilless culture.