30
2 High-Efficient Anaerobic Fermentation Technology of Organic …
amino acid that is bound in structures of protein molecules. This result probably
reveals that both protein-like fluorescent components present the spectral properties
of tryptophan and tyrosine bound into greater structures of organic molecules but
not the pure compounds in the fermentation process of two stages. The F max value
of component 2 decreased during the biodegradation of FVWs in the production
process of two stages except for pre-treatment with alkali. Whereas, component 2
showed a lower F max value than component 1.
For component 3, it presents three fluorescence peaks, whose maximum Ex/Em
wavelength pairs are centred at 205/425, 230/425 and 320/425 nm. These three
peaks are humic-like peaks of short wavelengths and deriving from fulvic-like substances. The presence of the component in the three fermentation stages was related
to allochthonous DOM stemming from terrestrial origins. The fulvic-like acid substance showed the lowest relative concentration in the component 3 among these three
components and except for control, a slightly higher concentration was detected after
methane production than that in other stages.
It can be observed from Fig. 2.13 that the F max value of humic-like substances
of component 3 was the lowest in all samples, whereas the highest values were
found for protein-like substances of components 1 and 2. Furthermore, except for
that in the control test, the abundance of component 1 was higher than components
2 and 3, which agrees well with the F max values. After pre-treating the FVWs,
the F max value of component 1 was increased substantially. The phenomenon was
mainly attributed to the newly produced DOM due to substrate hydrolysis. During
the comparison of the three pre-treatments for FVWs, protein-like components 1
and 2 were found degraded prominently after transiting from the hydrogenogenic
to the methanogenic stage during the pre-treatments with acid and enzyme. This
was a result of the hydrogen/methane production potentials and increased microbial
activities. Component 3 witnessed a slight increment in its amount after undergoing
degradation and metabolic processes in the anaerobic fermentation of two stages for
the three pre-treatments. Generally, additional quantitative information was offered
in the PARAFAC analysis. Based on the information, the distribution of the three
components in the DOMs of the fermentation effluents in different stages can be
described and the effect of different pre-treatments on FVWs is evaluated (Jia et al.
2014).
2.2.3 High-Efficient Pre-treatment Technology for Seed
Sludge
2.2.3.1 Influences of Pre-treatment on Biogas Production
To evaluate the efficiency of piggery anaerobic digested residues (PADRs) inocula,
a wide variety of treatment methods were utilized. Figure 2.14 displays the effects
of the different treatments on the cumulative production of biogas in batch tests of
2 High-Efficient Anaerobic Fermentation Technology of Organic …
amino acid that is bound in structures of protein molecules. This result probably
reveals that both protein-like fluorescent components present the spectral properties
of tryptophan and tyrosine bound into greater structures of organic molecules but
not the pure compounds in the fermentation process of two stages. The F max value
of component 2 decreased during the biodegradation of FVWs in the production
process of two stages except for pre-treatment with alkali. Whereas, component 2
showed a lower F max value than component 1.
For component 3, it presents three fluorescence peaks, whose maximum Ex/Em
wavelength pairs are centred at 205/425, 230/425 and 320/425 nm. These three
peaks are humic-like peaks of short wavelengths and deriving from fulvic-like substances. The presence of the component in the three fermentation stages was related
to allochthonous DOM stemming from terrestrial origins. The fulvic-like acid substance showed the lowest relative concentration in the component 3 among these three
components and except for control, a slightly higher concentration was detected after
methane production than that in other stages.
It can be observed from Fig. 2.13 that the F max value of humic-like substances
of component 3 was the lowest in all samples, whereas the highest values were
found for protein-like substances of components 1 and 2. Furthermore, except for
that in the control test, the abundance of component 1 was higher than components
2 and 3, which agrees well with the F max values. After pre-treating the FVWs,
the F max value of component 1 was increased substantially. The phenomenon was
mainly attributed to the newly produced DOM due to substrate hydrolysis. During
the comparison of the three pre-treatments for FVWs, protein-like components 1
and 2 were found degraded prominently after transiting from the hydrogenogenic
to the methanogenic stage during the pre-treatments with acid and enzyme. This
was a result of the hydrogen/methane production potentials and increased microbial
activities. Component 3 witnessed a slight increment in its amount after undergoing
degradation and metabolic processes in the anaerobic fermentation of two stages for
the three pre-treatments. Generally, additional quantitative information was offered
in the PARAFAC analysis. Based on the information, the distribution of the three
components in the DOMs of the fermentation effluents in different stages can be
described and the effect of different pre-treatments on FVWs is evaluated (Jia et al.
2014).
2.2.3 High-Efficient Pre-treatment Technology for Seed
Sludge
2.2.3.1 Influences of Pre-treatment on Biogas Production
To evaluate the efficiency of piggery anaerobic digested residues (PADRs) inocula,
a wide variety of treatment methods were utilized. Figure 2.14 displays the effects
of the different treatments on the cumulative production of biogas in batch tests of