Avoiding propionic acid accumulation in the anaerobic process for biohydrogen production

• Published in: Biomass & bioenergy Vol. 30; no. 2; pp. 177 - 182
• Main Authors: Wang, L., Zhou, Q., Li, F.T.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-02-2006; Elsevier
• Subjects: Acidogenic phase; Alternative fuels. Production and utilization; Applied sciences; Biohydrogen generation; Energy; Exact sciences and technology; Fuels; Hydrogen; Oxidation–reduction potential (ORP); Propionic acid accumulation; PH; Biohydrogen generation; Acidogenic phase; Oxidation–reduction potential (ORP); Propionic acid accumulation; Oxidation reduction; Ethanol; Propionic acid; pH; Fermentation; Anaerobic digestion; Hydrogen production; Oxidation-reduction potential (ORP)
• ISSN: 0961-9534; 1873-2909
• DOI: 10.1016/j.biombioe.2005.11.010

The accumulation of propionic acid in the anaerobic process will result in low efficiency of the methanogenic phase due to the low acetogenic rate of propionic acid, and hence low wastewater treatment efficiency. The reasons for propionic acid accumulation in the acidogenic phase and the relationship between the accumulation and biohydrogen generation were studied and a strategy for avoiding propionic acid accumulation in the anaerobic process for biohydrogen generation is also introduced. The experimental results indicate that changing pH and oxidation–reduction potential (ORP) can result in the variation of fermentation type, and maintaining lower ORP and avoiding pH of 5.5 will reduce the accumulation of propionic acid in the anaerobic process. Higher biohydrogen generation rate is not always accompanied with the accumulation of propionic acid. In the acidogenic reactor of two-phase separated anaerobic process, ethanol type fermentation, in which pH at 4.5 below, can produce much more biohydrogen but without accumulation of propionic acid. Thus, ethanol-type fermentation is a better selection when using an acidogenic reactor of a two-phase separated anaerobic process to efficiently produce biohydrogen with simultaneous organic wastewater pre-treatment.