Impacts of sterilization, microwave and ultrasonication pretreatment on hydrogen producing using waste sludge.

Hydrogen production by sterilization, microwave and ultrasonication pretreated waste sludge was investigated in this study. A new strain of Pseudomonas sp. GZ1 (EF551040) was inoculated in pretreated waste sludge to produce hydrogen. The experimental results showed that different pretreated sludge had evident differences in the yield of hydrogen production and lag time. Sterilized sludge had the largest yield of hydrogen production, and the maximum yield was 15.02 ml/gTCOD. The lag time of using sterilized sludge was 15 h, longer than other two pretreated sludge. Using the ultrasonicated sludge, the hydrogen production yield was smallest and lag time was shortest in the three pretreated sludge. Protein and carbohydrate could be released from waste sludge by pretreatment. Protein was the main nutrient used for hydrogen production. The concentration of protein, carbohydrate and SCOD increased after pretreatment and fermentation. The impacts of different pretreatments on hydrogen production were also discussed in detail.