The biogas produced by the microorganisms accumulates
at the top of the biodigesters (rigid dome), and then it is
conducted by pressure equalization and stored in the gasholders. There are two gasholders with 250 m
3 each at
DU ITAIPU, and the average biogas quality is 65% of CH 4
[methane], 34% of CO 2 [carbon dioxide], 600 ppm of H 2 S
[hydrogen sulfide], 1780 ppm of H 2 [hydrogen] and 0.8% of
O 2 [oxygen].
5 Biodigestion of Food Wastes
5.1 Biochemical Methane Potential (BMP)
The anaerobic biodigestion process occurs through the
combined and sequential action of several different groups of
microorganisms. Therefore, the efficiency of a biodigester
depends directly not only on the composition of the
microbial community but also on whether they are
metabolically active. The existence and activity of a certain
type of microorganism in a biodigester is related to the
operating temperature, pH, residence time and nutrients
present. Therefore, it is essential that the feeding of a
biodigester is carefully planned and executed.
The biodigestion process is basically divided into four
stages (hydrolysis, acidogenesis, acetogenesis and
methanogenesis, as previously described) which are performed by different groups of microorganisms, in syntropy,
and that require different nutritional conditions (Nathao et al.
2013). Providing all nutrients in a balanced way is important
so that all microorganisms that make up the microbial
community are able to operate in optimal conditions.
In most cases, a biodigestion plant is built in order to
degrade a specific type or a specific set of substrates. The
evaluation of the effect of feeding different types of substrates is therefore restricted to laboratory analysis. The
Fig. 3 Aerial view of the
demonstration unit—DU ITAIPU
Fig. 4 Flowchart of biogas
production from food wastes in
the Itaipu demonstration unit
Bioconversion of Food Waste to Biogas
103
at the top of the biodigesters (rigid dome), and then it is
conducted by pressure equalization and stored in the gasholders. There are two gasholders with 250 m
3 each at
DU ITAIPU, and the average biogas quality is 65% of CH 4
[methane], 34% of CO 2 [carbon dioxide], 600 ppm of H 2 S
[hydrogen sulfide], 1780 ppm of H 2 [hydrogen] and 0.8% of
O 2 [oxygen].
5 Biodigestion of Food Wastes
5.1 Biochemical Methane Potential (BMP)
The anaerobic biodigestion process occurs through the
combined and sequential action of several different groups of
microorganisms. Therefore, the efficiency of a biodigester
depends directly not only on the composition of the
microbial community but also on whether they are
metabolically active. The existence and activity of a certain
type of microorganism in a biodigester is related to the
operating temperature, pH, residence time and nutrients
present. Therefore, it is essential that the feeding of a
biodigester is carefully planned and executed.
The biodigestion process is basically divided into four
stages (hydrolysis, acidogenesis, acetogenesis and
methanogenesis, as previously described) which are performed by different groups of microorganisms, in syntropy,
and that require different nutritional conditions (Nathao et al.
2013). Providing all nutrients in a balanced way is important
so that all microorganisms that make up the microbial
community are able to operate in optimal conditions.
In most cases, a biodigestion plant is built in order to
degrade a specific type or a specific set of substrates. The
evaluation of the effect of feeding different types of substrates is therefore restricted to laboratory analysis. The
Fig. 3 Aerial view of the
demonstration unit—DU ITAIPU
Fig. 4 Flowchart of biogas
production from food wastes in
the Itaipu demonstration unit
Bioconversion of Food Waste to Biogas
103