Impacts of sterilization, microwave and ultrasonication pretreatment on hydrogen producing using waste sludge

Biological hydrogen production from sterilized sewage sludge by anaerobic self-fermentation

“…Massanet-Nicolau et al [29] reported that hydrogen fermentation of carbohydrates was the resource of hydrogen production in the anaerobic fermentation of sewage sludge. This result was different from that of Cai et al [11] and Guo et al [17] who thought that hydrogen was produced by the fermentation of proteins. The reason may be that both of the seeds and substrates of hydrogen production were different in these studies.…”

“…The butyric acid/acetic acid ratio was about 0.29 for the sterilized sludge, while about 0.17 for the raw sludge. Although this result was different from those of hydrogen fermentation of carbohydrates in many studies [31,32], it was similar to those of various pretreated sludge [11,17,29]. Guo et al [17] reported that no propionic acid and valeric acid were produced in the hydrogen fermentation of sterilized sludge by Pseudomonas sp.…”

“…Though the optimal temperature of thermal hydrolysis of sewage sludge was 170-175 • C [1,18], higher temperature would consume more energy. So, the conditions of thermal pretreatment were selected as 121 • C, 1.5 atm and 30 min of treatment time accordingly to the references [13,17,19]. After sterilizing, the pretreated sample (sterilized sludge, SS) was cooled to ambient temperature.…”

“…These released organics were degraded in the anaer- Cai et al [11] Alkaline pretreated sludge Consortiums in raw sludge Serum bottles 16.59 Massanet-Nicolau et al [29] Heat and enzymatic pretreated primary sewage sludge Consortiums in heated treated anaerobic sludge Batch reactor 18.14 Guo et al [17] Sterilization pretreated sludge Pseudomonas sp. GZ1 Batch reactor 30.38 obic self-fermentation (Fig.…”

“…Sterilized sludge (121 • C and 1.2 kgf/cm 2 for 30 min) was used to produce hydrogen by Clostridium bifermentans [13] and Pseudomonas sp. GZ1 [17].…”