Assessment of Digestate from Anaerobic Digestion of Fruit Vegetable Waste (FVW) as Potential Biofertilizer

Abstract The anaerobic digestion of fruit and vegetable waste (FVW) presents a promising approach for sustainable waste management and resource recovery. By characterizing its nutrient profile, this study explores the potential of FVW digestate as an organic fertilizer. FVW, comprising orange, Chinese cabbage, cucumber, and tomato, was processed into a slurry and mixed with anaerobic sludge as an inoculum in a pilot plant anaerobic digester. The digestion process, conducted in batch mode under ambient temperature, was monitored over 10 days, achieving a stable pH range of 6.5 to 7.5. Results showed that the FVW digestate contained significant concentrations of essential nutrients: nitrogen (5.4%), phosphorus (6470 mg/Kg), potassium (13700 mg/Kg), calcium (17400 mg/Kg), iron (11500 mg/Kg), magnesium (3840 mg/Kg), copper (88 mg/Kg), and zinc (574 mg/Kg). These findings indicate that FVW digestate is a viable source of organic fertilizer, offering a high nutrient content, particularly in potassium and calcium. However, nutrient concentrations varied from previous studies on food waste digestate, highlighting the influence of feedstock composition on anaerobic digestion outcomes. Future research should focus on assessing heavy metal content and exploring the effectiveness of FVW digestate in sustainable agricultural practices.