2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
- 44 -
In this study, a Thai MFC was developed
base on Low cost configuration. This reactor was
designed by using techniques to minimize the area
of cell transmission of oxygen from air to anaerobic
without membrane. This also used cheap materials
as electrodes as a microbial immobilization
substance to function as biocatalyst. This makes the
cost of production tools down several times (more
than 3,000 times the original cost).It hooked up
with carbon fiber brush as an immobilized base of a
bio-anode and air bio-cathode. Both parts separated
by long tube funnel. The optimum condition was
investigated by fed the POME in.
II. M
ATERIALS AND METHODS
Granular
activated
carbon
(GAC)
was
used
as
high
surface
electrode material. Three
anodes
chambers
and
a
single
cathode
chamber
were
filled
with
GAC
at
3:1
ratio
(v/v).
Total
void
volume
was
2.1
l.
In
place
of
a
proton
exchange
membrane,
a
funnel
was
installed
to
separate
the
anode
and
cathode
chambers.
Wastewater
was
fed
to
the
bottom
of
the
reactor,
passing
through
the
anode
chambers
and
overflowing
into
the
cathode
chamber.
The
cathode
was
oxygenated
via
sparkling-
holes
at
the
top
of
a
chamber.
A
circuit
was
completed
by
installing
a
copper wire whose
terminus
was
covered
with
graphite
felt.
Glass
beads
filled
the
bottom
of
the
anode
to
distribute
influent.
The
cost
of
this
design
was
about
US$2,273/m3
and
operating
power
consumption
was
<2.5
kWh/m3.
A.Thai microbial fuel cell
The Thai MFC has been developing from the
first model by substituted granular activated carbon
with carbon fiber brush in order to solve the reactor
clogging. The schematic was shown in Fig.1. It
consists of four cylindrical chambers: a cathode
chamber was located on the top of one of three
anode chambers. Carbon fiber brush was used as
high
surface bacterial immobilized base, which
connected directly to each graphite felt electrode.
A reverse funnel was installed to separate the anode
and cathode chambers in order to in place of an
expensive proton exchange membrane. Wastewater
was fed into at the bottom of the three anode
chambers stepwise and overflowing into the
cathode chamber. The cathode was oxygenated via
sparkling-holes at the top of the chamber. A circuit
was closed by installing a copper wire whose
terminus was covered with graphite felt electrode.
Fig. 1. Schematic of Thai microbial fuel cell.
B. Palm oil mill effluent properties
Filtrate POME COD concentration was 50-60
g/l
and pH 4.5-5.0. Adjusted POME pH by calcium
hydroxide to neutral pH before used. Total solid
(TS) and volatile solid (VS) were 39.04 ± 0.10 and
27.73 ± 0.05 g/l respectively.
C. Bacterial immobilized base preparation
Carbon fiber brushes were soaked into
suspended sludge mixture, which has MLSS
(Mixed liquor suspended solids) of 24.41 ± 0.23
g/l, under an anaerobic condition for three days.
Subsequently, some of them were set in three
anaerobic anode parts. The others were set in an
aerobic cathode part and aerated at 200 ml/min.
Diluted POME about 6.0 g COD/l was fed into as
start up culture and left it for a week until the open
circuit voltage shown at least 0.5 V. The
experiment was conducted under ambient
temperature (27 ± 3 0C).
Each experiment had
operated for three days until the voltage signal was
stable. Triple influent and effluent were sampling at
the beginning and the end of the day third. Each
sample COD concentration was analyzed. A power
potential was automatically recorded every 100 min
by data logger program (National Instruments USB
6008).
