Thermophilic fermentation of household food waste

Abstract

In mesophilic conditions, anaerobic digestion is the most common in the world. However, thermophilic fermentation has several advantages due to the growth rate of microorganisms and the reactions they produce, as well as the degradation of deep organic matter due to an increase in the solubility of organic compounds. Increasing the temperature of the process makes it possible to neutralize the remnants of pathogenic organisms (viruses, bacteria, helminth eggs), which are necessary for the further use of fermented biomass as a biofertilizer. An effective inoculum is selected for the process of anaerobic co-fermentation of food waste and excess activated sludge. The optimal ratio of inoculate and substrate is determined to start the process of anaerobic digestion. Experiments with flasks and laboratory biogas reactors demonstrate that fermentation of OSV with food waste can significantly increase the rate and consumption of biogas. The optimal ratio of OSV and food waste in a mixture of coenzymes is 50/50, depending on the total content of organic substances in the mixture. The maximum rate of methanogenesis is observed in mixtures of I/C 70/30 and I/C 55/45 (after 18 days) and 156 ml of CH4 and 178 ml of CH4, respectively. This indicates the stability of the anaerobic process. It is shown that after pretreatment and activation of the landfill, the organic part of solid household waste, food waste and wastewater can be used to start the process of anaerobic digestion in anaerobic reactors.