Biohydrogen Production From Food Waste by Anaerobic Fermentation

The biohydrogen production from food wastes by anaerobic fermentation of digested sludge is studied. It is found by gas chromatography analysis that the volumetric ratios of H₂ to CO₂ in the biogases derived from rice, potato, lean meat and fat are respectively 0.77, 0.82, 0.93 and 0.82. The yield of methane is quite little, because the methane-producing activity is restrained and the hydrogen-producing activity is simultaneously kept when the digested sludge is preheated in the boiling water. Ethanol (0.43%) is the highest volatile fatty acid in the fermentation solution derived from lean meat, implying that it belongs to ethanol-type fermentation. The butyric acid concentrations are the highest (respectively 0.96%, 0.44% and 0.34%) in the fermentation solutions derived from rice, potato and fat, which implies that they all belong to butyric acid-type fermentation.