초록
<P><B>Abstract</B></P> <P>This paper investigates the production of hydrogen (H<SUB>2</SUB>) and methane (CH<SUB>4</SUB>) from palm oil mill effluent (POME) using an integrated approach of thermophilic continuous stirred tank reactor (CSTR) and mesophilic microbial electrolysis cell (MECs). CSTR reactor was operated at pH 5.5, 80 rpm, 2 days HRT, 60 g COD L<SUP>-1</SUP> d<SUP>-1</SUP> organic loading rate (OLR) and 55 °C temperature with the given hydrogen yield of 205 ml H<SUB>2</SUB> gCOD<SUP>-1</SUP> along with acetic, butyric, propionic, and lactic acid as by-products. Continuous, single-chambered MECs fed with dark fermentation effluents were operated at an applied voltage of 0.5 V at 37 °C to obtain methane yield and production rate (MPR) of 290 ml CH<SUB>4</SUB> gCOD<SUP>-1</SUP> and 2700 ml CH<SUB>4</SUB> L<SUP>-1</SUP> at 8 days of hydraulic retention times (HRT). The overall process led to total energy recovery of 92.72% with 91% COD removal efficiency. Microbial community analysis reveals <I>Thermoanerobacterium</I> sp dominated in CSTR whereas exoelectrogens of <I>Methanobacterium formicicum</I> and <I>Methanobacterium beijingense</I> were found to be the chief dominant microbial species on anodic electrode of MECs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sequential hydrogen and methane production were produced from palm oil mill effluent via two-stage bioprocess. </LI> <LI> CSTR and MEC were operated at different HRT, OLR, and temperature for optimal gas production. </LI> <LI> Microbial Electrolysis Cell reactor showed a maximum methane production rate of 2700 ml CH<SUB>4</SUB> L<SUP>-1</SUP> at HRT of 8 days. </LI> <LI> The Anodic electrode of MEC was dominated by <I>Methanobacterium formicicum</I> and <I>Methanobacterium beijingense.</I> </LI> </UL> </P>