Anaerobic digestion in the fruit waste disposal and valorization

Abstract

Due to their characteristics, a significant portion of fruit produced on a large scale, especially kiwi, is wasted as organic waste. This problem has created an opportunity to evaluated the potential for biogas generation using kiwi waste as a substrate by the anaerobic process. Eight distinct assays were performed in two batch reactors (R1 and R18). Different substrate/inoculum ratios, addition of NaHCO3 and with and without nutrients addition were tested. The most satisfactory results were obtained with: kiwi waste (8.4 g), anaerobic digester slurry (192 mL), sodium bicarbonate (500.4mg), ammonium chloride (453.0mg) and potassium phosphate monobasic (106.0mg) added. In this assay, 759.1 mL biogas/g VS was produced and methane quality of 60%, indicating that kiwi fruit waste has potential for biogas production. It is also concluded that the quality of the inoculum and substrate/inoculum ratio influences the biogas production.