nutrients and energy while stabilizing any organics and chemicals, eliminating
pathogens, reducing GHG emissions, and eliminating the risk of soil and water
pollution. Digestate from methane or hydrogen-producing anaerobic digestion is
concentrated with nutrients and is an excellent fertilizer which contains nitrogen,
phosphorus, and other nutrients but less carbon. Livestock manure is a good
substrate for H 2 production because it is cheap, carbohydrate-rich (contains cellulose
and hemicellulose), and biodegradable.
Manure can be utilized as a substrate, a co-substrate, a source of nutrient, and a
buffer agent for H 2 -producing anaerobic mixed cultures. Table 8.10 gives the
reported H 2 yield and production rate from livestock and dairy waste. A yield of
59.5 mL H 2 /g VS fed has been obtained from 40 g VS/L of 70:30 cow manure/waste
milk mixture in thermophilic (55
C) batch reactors [204]. The H 2 yield from waste
milk has been increased by 60 times when cow manure has been used as a
co-substrate because it prevented acidogenic inhibition due to the high rate of
hydrolysis [204]. Fermenting sucrose with dairy manure at ambient temperature
yielded 2.9–5.3 mol H 2 /mol sucrose [205]. The cattle manure provided stability to
the fermentation by maintaining the pH level because it has an excellent buffering
capacity [123, 205] and provided the mixed anaerobic culture with the necessary
nutrients [205]. Swine manure supplemented with glucose yielded 1.48 L H 2 /L
substrate in mesophilic (37
C) ASBR [208]. A stable co-fermentation of fruitvegetable waste and swine manure produced 126 mL H 2 /g VS at an HRT of
2 days [123]. No difference in H 2 yield from dairy manure could be observed
when it was pretreated with acid (0.2% HCl boiling for 30 min), base (0.2%
NaOH boiling for 30 min), or infrared radiation (2 h) to hydrolyze the lignocellulosic
fiber [202].
4 Inocula for Hydrogen Production from Waste
4.1 Sources of Inocula
For sustainable waste treatment, the inoculum has to be obtained from sustainable
open sources. Sludge from municipal and industrial wastewater treatment processes
(both anaerobic digestion and activated sludge processes), compost, cow dung, and
agriculture soil are sustainable natural open sources for anaerobic mixed culture.
4.1.1 Sewage Sludge
Anaerobic sludge from primary and secondary digesters in municipal wastewater
treatment plants is a readily accessible and cheap source of inoculum which could be
used after a proper pretreatment to produce H 2 in dark fermentation. Therefore, it has
been widely used in H 2 dark fermentation studies from industrial waste [67, 91, 93,
8 Biohydrogen of Industrial Waste
347
pathogens, reducing GHG emissions, and eliminating the risk of soil and water
pollution. Digestate from methane or hydrogen-producing anaerobic digestion is
concentrated with nutrients and is an excellent fertilizer which contains nitrogen,
phosphorus, and other nutrients but less carbon. Livestock manure is a good
substrate for H 2 production because it is cheap, carbohydrate-rich (contains cellulose
and hemicellulose), and biodegradable.
Manure can be utilized as a substrate, a co-substrate, a source of nutrient, and a
buffer agent for H 2 -producing anaerobic mixed cultures. Table 8.10 gives the
reported H 2 yield and production rate from livestock and dairy waste. A yield of
59.5 mL H 2 /g VS fed has been obtained from 40 g VS/L of 70:30 cow manure/waste
milk mixture in thermophilic (55
C) batch reactors [204]. The H 2 yield from waste
milk has been increased by 60 times when cow manure has been used as a
co-substrate because it prevented acidogenic inhibition due to the high rate of
hydrolysis [204]. Fermenting sucrose with dairy manure at ambient temperature
yielded 2.9–5.3 mol H 2 /mol sucrose [205]. The cattle manure provided stability to
the fermentation by maintaining the pH level because it has an excellent buffering
capacity [123, 205] and provided the mixed anaerobic culture with the necessary
nutrients [205]. Swine manure supplemented with glucose yielded 1.48 L H 2 /L
substrate in mesophilic (37
C) ASBR [208]. A stable co-fermentation of fruitvegetable waste and swine manure produced 126 mL H 2 /g VS at an HRT of
2 days [123]. No difference in H 2 yield from dairy manure could be observed
when it was pretreated with acid (0.2% HCl boiling for 30 min), base (0.2%
NaOH boiling for 30 min), or infrared radiation (2 h) to hydrolyze the lignocellulosic
fiber [202].
4 Inocula for Hydrogen Production from Waste
4.1 Sources of Inocula
For sustainable waste treatment, the inoculum has to be obtained from sustainable
open sources. Sludge from municipal and industrial wastewater treatment processes
(both anaerobic digestion and activated sludge processes), compost, cow dung, and
agriculture soil are sustainable natural open sources for anaerobic mixed culture.
4.1.1 Sewage Sludge
Anaerobic sludge from primary and secondary digesters in municipal wastewater
treatment plants is a readily accessible and cheap source of inoculum which could be
used after a proper pretreatment to produce H 2 in dark fermentation. Therefore, it has
been widely used in H 2 dark fermentation studies from industrial waste [67, 91, 93,
8 Biohydrogen of Industrial Waste
347