7 Future Research on Biohydrogen Production
from Industrial Waste Dark Fermentation
The near future research focus should be on integrating the possible combinations of
industrial wastes in a dark fermentative H 2 -producing process utilizing the same CH 4
fermentation infrastructures. The effluent of dark fermentation has high levels of
VFAs. Therefore, integration of dark fermentative H 2 production and other
bioprocesses that utilize VFAs for producing biofuels or value-added chemicals
such as bioplastics [248] or lipid synthesis by microalgae for biodiesel production
[249] should be investigated. The stability of the mixed culture integrity is a big
concern, particularly after inoculum pretreatment to prepare an H 2 -producing consortium because the waste is a source of contamination. Therefore, industrial waste,
which contains inhibitors to methanogens, could be investigated as a potential tool to
maintain the integrity of the culture during dark fermentation of other waste which
has a high H 2 potential. Future research should focus on the application of the
molecular biology methods and techniques in microbial characterization to understanding the composition of the microbial consortium for mixed cultures [250]. Cost
analysis for H 2 production from various industrial wastes is required to enable sound
evaluation of alternatives.
8 Conclusions
Hydrogen production from biodegradable industrial waste is possible, but its yield
and production rate depend on the type of waste. Carbohydrate-rich waste such as
molasses, starch, corn syrup, etc. is an excellent substrate for H 2 production because
they support high yield in relatively short hydraulic retention time. There is a lack of
modeling studies of H 2 production from industrial waste as well as comparative
studies about the effect of bioreactor design on the H 2 yield and rate from the same
waste. An important area of research is an integrative strategy where several wastes
are combined to prepare a well-balanced substrate for H 2 -producing mixed culture
dark fermentation. More studies are required on the cost analysis and economic
evaluation of H 2 production from dark anaerobic fermentation of industrial waste.
No specific culture pretreatment can be considered as the best pretreatment for
maximizing H 2 yields from industrial waste. Detailed energy analysis for a wide
spectrum of industrial wastes is required to establish the net energy yield for various
wastes, reactor designs, pretreatments, and operation conditions. Although the
results from laboratory-scale studies of producing H 2 from industrial waste were
promising, no pilot plant or large-scale studies have been reported.
356
A. Hajizadeh et al.
from Industrial Waste Dark Fermentation
The near future research focus should be on integrating the possible combinations of
industrial wastes in a dark fermentative H 2 -producing process utilizing the same CH 4
fermentation infrastructures. The effluent of dark fermentation has high levels of
VFAs. Therefore, integration of dark fermentative H 2 production and other
bioprocesses that utilize VFAs for producing biofuels or value-added chemicals
such as bioplastics [248] or lipid synthesis by microalgae for biodiesel production
[249] should be investigated. The stability of the mixed culture integrity is a big
concern, particularly after inoculum pretreatment to prepare an H 2 -producing consortium because the waste is a source of contamination. Therefore, industrial waste,
which contains inhibitors to methanogens, could be investigated as a potential tool to
maintain the integrity of the culture during dark fermentation of other waste which
has a high H 2 potential. Future research should focus on the application of the
molecular biology methods and techniques in microbial characterization to understanding the composition of the microbial consortium for mixed cultures [250]. Cost
analysis for H 2 production from various industrial wastes is required to enable sound
evaluation of alternatives.
8 Conclusions
Hydrogen production from biodegradable industrial waste is possible, but its yield
and production rate depend on the type of waste. Carbohydrate-rich waste such as
molasses, starch, corn syrup, etc. is an excellent substrate for H 2 production because
they support high yield in relatively short hydraulic retention time. There is a lack of
modeling studies of H 2 production from industrial waste as well as comparative
studies about the effect of bioreactor design on the H 2 yield and rate from the same
waste. An important area of research is an integrative strategy where several wastes
are combined to prepare a well-balanced substrate for H 2 -producing mixed culture
dark fermentation. More studies are required on the cost analysis and economic
evaluation of H 2 production from dark anaerobic fermentation of industrial waste.
No specific culture pretreatment can be considered as the best pretreatment for
maximizing H 2 yields from industrial waste. Detailed energy analysis for a wide
spectrum of industrial wastes is required to establish the net energy yield for various
wastes, reactor designs, pretreatments, and operation conditions. Although the
results from laboratory-scale studies of producing H 2 from industrial waste were
promising, no pilot plant or large-scale studies have been reported.
356
A. Hajizadeh et al.