Impact of Kitchen Waste Hydrothermal Pre-treatment on Anaerobic Fermentation Type and Hydrogen Production

Batch tests were carried out to analyze the influences of hydrothermal pre-treatment on anaerobic fermentation type and hydrogen production by measuring the variation of soluble chemical oxygen demand (CODs), total chemical oxygen demand (CODt), crude protein content, C/N and metabolites. Using Gompertz kinetics model, the change of anaerobic fermentation system boot speed, cumulative hydrogen production and hydrogen production rate caused by hydrothermal pre-treatment were studied. The result showed that floatable oil could be affected by hydrothermal pre-treatment which obtained a maximum yield of 97.5 mL/kg, and then the content of CODs and C/N changed significantly. The analysis of VFAs and ethanol concentration proved that hydrothermal pre-treatment can change the kitchen waste anaerobic metabolic pathways of hydrogen production from mainly propionic acid into butyric acid metabolic pathways. The 90℃-30 min pre-treatment which got a highest degree of specific hydrogen production yield at 242.1 mL/g(VSS) could shift the butyric acid into acetic acid and hydrogen by the effect of microorganism. The hydrothermal pre-treatment could affect the characteristic of carbohydrates, protein and fat in kitchen waste, thereby affecting hydrogen and acid production by anaerobic fermentation type of kitchen waste to achieve the purposes of enhancing the efficiency of hydrogen production performance by kitchen waste anaerobic hydrogen production.