Continuous Pro-Hydrogen by Anaerobic Fermentation of Municipal Sludge

Abstract

Biological hydrogen production from the anaerobic fermentation of ultrasound-pretreated municipal sludge started at pH of 5.5–6.5 and temperature of 36.5 °C. The present study examined the effects of sludge residence time (SRT), organic loading rate (OLR), oxidation-reduction potential (ORP), and agitation intensity (AI) on continuous hydrogen production by anaerobic sludge fermentation. The result showed that a higher hydrogen production yield was achieved with optimal control of the system. In this study, the optimized parameters consisted of SRT = 32 h, OLR = 0.3 kg COD·d⁻¹, ORP between −330 and −310 mV, and AI = 1,500–2,000 rpm; as a result, the hydrogen yield was 41.6 mL·g⁻¹(volatile solid, VS), hydrogen production rate was 32.7–37.8 L/(kgCOD·d⁻¹), hydrogen concentration achieved was as high as 57.7%, and the organic matter utilization ratio was more than 25.3% with no methane detected.

Keywords:

• Ultrasonic wave
• Municipal sludge
• Anaerobic fermentation
• Biological hydrogen production

ACKNOWLEDGEMENTS

We are greatly indebted to the State Ministry of Science and Technology (2008BAE64B05, 2006BAJ04A12-4), the State Key Laboratory of Subtropical Building Science (2009ZB05, 2010ZB04) of China.