Year: 2009
Type: dissertation
Abstract: A laboratory-scale anaerobic Fluidised Bed Bioreactor (FBBR) was designed and \nconstructed for hydrogen gas (H2) production using a sucrose-based synthetic \nwastewater. In the first experiment, the anaerobic FBBR was inoculated with two \nfacultative anaerobic bacteria Citrobacter freundii (Cf1) (Accession number: \nEU046372) and Enterobacter cloacae (Ecl) (Accession number: EU046373) to study \ntheir H2 productivity capacity. Granulated activated carbon was used to initiate the \ngrowth and development of bacterial granules. For granule production the hydraulic \nretention time (HRT) was gradually reduced from 8 to 0.5 h. Hydrogen production \nand sucrose consumption was investigated at HRTs ranging from 8 to 0.5 h. Sucrose \nwas converted into volatile fatty acids (VFAs) and biogas (essentially H2). \nTemperature and pH of the anaerobic FBBR were controlled at 37±1ºC and 5.6±0.1 \nrespectively. The H2 production rate (HPR) reached 138mmol/(h.L) at 0.5 h HRT. \nAcetic, butyric and propionic acids were detected at 104.5±21.06, 76.13±16.81 and \n24.91±2.67 mg/L respectively. Results showed that Ecl and Cf1 were able to convert \nsucrose into soluble and biogas products with high rate of H2 gas production. \nIn the second experiment, a heat and acid treated sample of activated sewage sludge \nfrom an anaerobic sewage works was used as the inoculum for growing the granular \nbed in the anaerobic FBBR. The anaerobic FBBR was operated according to \nconditions described in the first experiment. HPR reached a maximum of 130.1 \nmmol/(h.L) at 0.5 h HRT with constant influent sucrose concentration of 17.65 g/L. \nIn both experiments the influent sucrose concentration in the bioreactor expressed in \nterms of chemical oxygen demand (COD) was 20 gCOD/L. Optimal sucrose to \nhydrogen ration was observed at a HRT of 2 h and led to a H2 yield (YH2) of 1.61 \nmmol-H2/mmol-sucrose.
Author: Bukasa Kalala
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2240165472