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Thesis Title Hydrogen and Methane Production by a Two-Stage Anaerobic
Digestion of Palm Oil Mill Effluent
Author Miss Khaleeyah Sani
Major Program Applied Chemistry
Academic Year 2015

ABSTRACT

This study aimed to investigate biochemical hydrogen and methane
potential in single and two stages anaerobic digestion process from different initial
o
concentrations of palm oil mill effluent (POME) under thermophilic (55 ±3 C) and
o
mesophilic (30 ±3 C) conditions for biohydrogen and methane production, respectively,
in batch and continuous reactor. The result shown that, the best biochemical
hydrogen potential of 142.9 mL-H 2/g-VS which was obtained from anaerobic digested
of POME with the initial concentration of 10 g-VS/L. Subsequently, the effluent
achieved from hydrogen production stage was further used as substrate for methane
production stage. The highest methane yield of 356.4 mL-CH 4/g-VS was obtained

from a two-stage anaerobic digestion process, while, a single stage anaerobic
digestion process yielded methane of 285.5 mL-CH 4/g-VS. The investigation revealed
that approximately 20 % of methane yield achieved from a two-stage anaerobic
digestion process was higher than a single stage anaerobic digestion process and the
highest energy yield was about 12.97 kJ/g-VS. Therefore, a two-stage anaerobic
digestion process is a processing choice to enhance methane and energy yield.
Furthermore, the two-stage process for continuous hydrogen and methane
production was investigated in continuously stirred sank reactor (CSTR) reactors for
first stage and plug flow reactor (PFR) for second stage. Specific hydrogen and

methane yields of 156 and 429 mL/g-VS, respectively were achieved simultaneously
with the overall COD removal efficiency of 81% by operating with hydraulic retention
time (HRT) of 3 d and 35 d for the CSTR and PFR reactor, respectively. This research
work demonstrated a feasible approach of use POME, the industrial organic to
generate valuable bioenergy from a two-stage anaerobic digestion process.