Hydrogen-producing capability of anaerobic activated sludge in three type fermentations in a continuous stirred-tank reactor

摘要

A continuous stirred-tank reactor (CSTR) was introduced to anaerobic activated sludge process for hydrogen production by fermentation and hydrogen-producing capabilities of three typical fermentation, i.e. propionic acid fermentation, butyric acid fermentation and ethanol fermentation were investigated under the same organic loading rate (OLR) and temperature. The reactor was fed with diluted molasses continuously with a COD concentration of 5000 mg/L and a hydraulic retention time (HRT) of 8 h under the temperature 35°C. The results indicated that the specific hydrogen-producing rate of the anaerobic activated sludge in ethanol type fermentation reached 2.96 mol per kilogram mixed liquid volatile suspended solid (MLVSS) per day (mol/kgMLVSS/d), while 0.57 mol/kgMLVSS/d in butyric acid type fermentation and 0.022 mol/kgMLVSS/d in propionic acid type fermentation, respectively. The hydrogen-producing capability of the anaerobic activated sludge in ethanol type fermentation was 4.11 times as much as that in butyric acid type fermentation and 148 times in propionic acid type fermentation. This result suggested that ethanol type fermentation is the optimum process for hydrogen production by organic wastewater fermentation.