2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
- 95 -
reactors. The graphs showed that when the system was
fed with glucose-based substrate, the biogas produced
from the anaerobic fermentation contained mainly H
2
(Figs. 1a, 2a and 3a) with comparatively small amounts
of CH
4
(Figs. 1b, 2b and 3b). On the opposite site, when
the system was fed with the brewery wastewater, the
biogas produced from the anaerobic fermentation
contained mainly CH
4
(Figs. 1b, 2b and 3b), with non
detectable hydrogen (Figs. 1a, 2a and 3a).
(a)
(b)
Fig. 1. Time course of H
2
(Fig. 1 a) and CH
4
content (Fig. 1 b) from
the bioreactor that contained heat pretreated bacteria.
(a)
(b)
Fig. 2. Time course of H
2
(Fig. 2 a) and CH
4
content (Fig. 2 b) from
the bioreactor that contained acid pretreated bacteria.
The first 15 days of the semi continuous operation
represents the starting up of the reactor fed with glucose-
based substrate, during this time the H
2
content of the
biogas increased to 20-40 percent (Figs 1a, 2a and 3a)
indicating that the heat, acid and base pretreated mixed
bacteria can produce H
2
from the glucose-based
solution. The system produces its greatest H
2
content
during the first 15 days. After day 15, brewery
wastewater commingled with glucose-based substrate
was fed to the reactors for 5 days, resulting in a decrease
of H
2
in the biogas (Figs 1a, 2a and 3a). After day 20,
brewery wastewater alone was fed to the system. At this
stage the H
2
production ceased (Figs 1a, 2a and 3a) and
the system could not recover H
2
generation through use
of brewery wastewater. This reduction and cessation of
H
2
production leads to the conclusion that, although, the
heat, acid and base pretreatment methods adopted for
increasing the H
2
production from use of the anaerobic
inoculum were effective for the glucose-based substrate
but were not for brewery wastewater under the tested
conditions. Normal brewery wastewater was not
appropriate for H
2
production. This is probably due to
the fact that brewery wastewater contains less
biodegradable organic material and nutrients to support
the growth of bacteria compared with the glucose-
based substrate. The characteristics of the brewery
wastewater in this current study were analyzed and
recorded in Table 2.
Another possible reason is H
2
utilizing methanogens could not be completely
suppressed by those pretreatment methods (heat,
acid and base pretreatment).
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60
H
2
(%)
Time (days)
Glucose-based substrate
Brewery wastewater
