Biological hydrogen production by anaerobic digestion of food waste and sewage sludge treated using various pretreatment technologies

The purpose of this study was to enhance the efficiency of anaerobic co-digestion with sewage sludge using pretreatment technologies and food waste. We studied the effects of various pretreatment methods (thermal, chemical, ultrasonic, and their combination) on hydrogen production and the characteristics of volatile fatty acids (VFAs) using sewage sludge alone and a mixture of sewage sludge and food waste. The pretreatment combination of alkalization and ultrasonication performed best, effecting a high solubilization rate and high hydrogen production (13.8 mL H₂/g VSS_consumed). At a food waste:pretreated sewage sludge ratio of 2:1 in the mixture, the peak hydrogen production value was 5.0 L H₂/L/d. As the production of hydrogen increased, propionate levels fell but butyrate concentrations rose gradually.