Impact of Mineral Fertilizers on Anaerobic Digestion of Vegetable Waste

Abstract

This study investigated the use of mineral fertilizers for the improvement of biogas production from vegetable wastes. Five fertilizers of various chemical compositions were selected, and two blends of vegetable wastes were composed for the experiments. The results demonstrated the highest improvement in biogas production using the mineral fertilizer SUBSTRAL dedicated to conifers, which was characterized by a diverse chemical composition and the lack of sulfur. The addition of this fertilizer in a dose of 1 g/kg increased methane and hydrogen yields by up to 49% compared to the control. The maximum methane production of 336 NmL/gVS was achieved after supplementation of the mixture containing corn, green peas, and green bean wastes, whereas the highest hydrogen yield of 49 NmL/gVS was reported in the experiments with the blend containing carrot, cauliflower, and broccoli. A simplified cost analysis showed that the use of 1 kg of mineral fertilizer to supplement the anaerobic digestion of vegetable waste for biogas production can generate additional revenues of up to 2399 €.