초록
<P><B>Abstract</B></P> <P>The pilot-scale of two-stage thermophilic (55 °C) for biohythane production from palm oil mill effluent (POME) was operated at hydraulic retention time (HRT) of 2 days and organic loading rate (OLR) of 27.5 gCOD/L⋅d) for first stage and HRT of 10 days and OLR of 5.5 gCOD/L⋅d for second stage. Biohythane production rate was 1.93 L-gas/L⋅d with biogas containing 11% H<SUB>2</SUB>, 37% CO<SUB>2</SUB>, and 52% CH<SUB>4</SUB>. Recirculation of methane effluent mixed with POME at a ratio of 1:1 can control pH in the first stage at an optimal range of 5.0–6.5. Microbial community in hydrogen stage dominated by <I>Thermoanaerobacterium</I> sp., while methane stage dominated by <I>Methanosarcina</I> sp. The H<SUB>2</SUB>/CH<SUB>4</SUB> ratio of biohythane was 0.13–0.18 which suitable for vehicle fuel. Biohythane production from POME could be promising cleaner biofuel with flexible and controllable H<SUB>2</SUB>/CH<SUB>4</SUB> ratio.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The two-stage pilot-scale reactor was operated for biohythane production from POME. </LI> <LI> Biohythane production rate of 1.93 L/L/d containing 11% H<SUB>2</SUB> and 52% CH<SUB>4</SUB> was achieved. </LI> <LI> The H<SUB>2</SUB>/CH<SUB>4</SUB> ratio of biohythane was 0.13–0.18 which suitable for vehicle fuel. </LI> <LI> Biohythane could be cleaner biofuel with flexible and controllable H<SUB>2</SUB>/CH<SUB>4</SUB> ratio. </LI> </UL> </P>