 Biohydrogen Production from Renewable
Organic Wastes
Additional Information
Biomass
Biomass Case Studies
BECON Facility
Ethanol Information
Grant # 01-01
Principal Investigator: Shihwu Sung
Organization: Iowa State University
Technical Area: Renewable Energy
Executive Summary (130 KB)
Full Report PDF (4.55 MB)
Public Abstract
The goals of the research were to investigate biological hydrogen production through kinetic study, reactor operation, and microbial population analysis. The kinetics of hydrogen production using different characteristics of substrates (sucrose, non-fat dry milk, and food waste) was investigated in the study. Hydrogen production bio-catalyzed in an anaerobic sequencing batch reactor (ASBR) was optimized by HRT, pH, and substrate concentration. Sucrose was used to mimic the real organic waste. Fluorescent in situ hybridization (FISH) was applied to identify microbial populations. In the kinetic study, Michaelis-Menten equation was employed to describe the relation between hydrogen production rate and substrate concentration. The values of half saturation constant (KS) for sucrose, non-fat dry milk, and food waste were 1.4, 6.6, and 8.7 g COD/L, respectively. The substrate containing higher carbohydrates showed a lower KS value. In addition, it also found that particulate organic waste was not appropriate for fermentative hydrogen production. In the continuous operation, the maximum hydrogen yield of 2.53 mol H2/mol sucroseconsumed and the maximum hydrogenic activity of 538 mL H2/g VSS-d were obtained at HRT of 16h, pH 4.9, and sucrose concentration of 25 g COD/L. As aspect of acid fermentation, the metabolic pathway of acetate fermentation was predominant at higher sucrose concentrations. The result of low ethanol concentration elaborated that the metabolic pathway shift to solvent fermentation was not observed at pH of 4.9. FISH analysis observed that most bacteria successfully identified by an EUB338 probe. Due to the false positive hybridization results, the ARC915 probe was found unsuitable for identifying cells belonging to the domain Archaea in this study. CLOST I probe determined clostridia cluster I in the study. However, it found that autofluorescence and background color could intensively disturb the observation under fluorescent microscope. Anaerobic bioconversion of organic wastes to hydrogen gas is an attractive option that not only stabilizes the waste/wastewater, but also generates a benign renewable energy carrier.
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