초록
<P><B>Abstract</B></P> <P>Biohydrogen production from palm oil mill effluent (POME) using <I>Thermoanaerobacterium thermosaccharolyticum</I> PSU-2-rich sludge was conducted in a 5L continuous stirred tank reactor (CSTR). Mixing of effluent is crucial factor for hydrogen yield and net energy gain. Two types of turbines, namely the Rushton turbine and paddle turbine at 10, 50, 100, and 150rpm were the comparative factors in this study. The operating parameters were 60°C, 24-h hydraulic retention time (HRT), and 55gCOD L<SUB>influent</SUB> <SUP>−1</SUP> d<SUP>−1</SUP> organic loading rate (OLR). Computational fluid dynamics (CFD) was employed to understand the flow pattern, including dead zones and swirls of effluent in the CSTR. Mixing by Rushton turbine developed lesser dead zone and better mixing swirl than those of paddle turbine. At all mixing speeds, higher hydrogen yield was obtained when a Rushton turbine was applied. The highest hydrogen yield was 6826mL H<SUB>2</SUB> L<SUB>POME</SUB> <SUP>−1</SUP> (350mL H<SUB>2</SUB> gCOD<SUP>−1</SUP>) at 150rpm. However, the operating speed to achieve the maximum net energy gain (of 29.95kJ) was 100rpm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Rushton turbine was superior to paddle turbine in hydrogen production in CSTR. </LI> <LI> The highest hydrogen yield was 325mL H<SUB>2</SUB> gCOD<SUP>−1</SUP> at 150rpm mixing speed. </LI> <LI> The highest net energy gain was 29.95kJ at 100rpm mixing with Rushton turbine. </LI> <LI> Gas production was clearly explained by flow patterns and dead zone from CFD simulations. </LI> </UL> </P>