European Journal of Biomedical and Pharmaceutical Sciences

CARBON DIOXIDE DEPLETION DURING H2/CO2 AND BIOGAS FERMENTATION IN CHEMOSTAT STIRRED TANK REACTORS: EFFECT OF HYDRAULIC RETENTION TIME

AKO Olga Yolande. Aké.*, TIAMA Ballet Guy, TANOE Fernandez Koffi and AKA Boko

ABSTRACT

Microorganisms are preferentially used in energy production from biomass because less expensive and normally more resistant to the gas contaminants such as hydrogen sulfide. In the present study, the stoichiometric relation of CO2 conversion to methane in the presence of H2, was used to investigate the effect of hydraulic retention time (HRT) on H2/CO2 fermentation aiming at evaluating the carbon dioxide depletion. Four chemostat stirred tank reactors operating at 37 °C in presence of fix amount of H2/CO2 gas (80:20; v/v) by means of 12L/reactor /day) were used. The carbon dioxide removal rate was found to increase when the hydraulic retention time increased. At HRT of 8; 10; 12; 14 days CO2 removal rate were 82.2; 86.7; 90.7 and 92.8%, respectively. The food to Microorganisms (F/M) ratio was found to also be related to the hydraulic retention time; the Food to microorganism ratio decrease with the HRT. The replacement of mix H2/CO2 gas by the biogas from wastewater treatment plant obtain also a CO2 depletion and the methane fraction enrichment in the biogas.

Keywords: CO2 depletion; H2/CO2; Biogas; food to microorganisms’ ratio; gas recirculation; inorganic substrate.