Effect of polyhydroxyalkanoates on dark fermentative hydrogen production from waste activated sludge

Wang, Dongbo, Zeng, Guangming, Chen, Yinguang and Li, Xiaoming (2015) Effect of polyhydroxyalkanoates on dark fermentative hydrogen production from waste activated sludge. Water Research, 73 311-322. doi:10.1016/j.watres.2015.01.017

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Author Wang, Dongbo
Zeng, Guangming
Chen, Yinguang
Li, Xiaoming
Title Effect of polyhydroxyalkanoates on dark fermentative hydrogen production from waste activated sludge
Journal name Water Research   Check publisher's open access policy
ISSN 0043-1354
1879-2448
Publication date 2015-04-05
Year available 2015
Sub-type Article (original research)
DOI 10.1016/j.watres.2015.01.017
Open Access Status File (Author Post-print)
Volume 73
Start page 311
End page 322
Total pages 12
Place of publication London, United Kingdom
Publisher I W A Publishing
Language eng
Subject 2302 Ecological Modelling
2312 Water Science and Technology
2311 Waste Management and Disposal
2310 Pollution
Abstract Polyhydroxyalkanoates (PHA), an intracellular energy and carbon storage polymer, can be accumulated in activated sludge in substantial quantities under wastewater dynamic treatment (i.e., substrate feast-famine) conditions. However, its influence on hydrogen production has never been investigated before. This study therefore evaluated the influences of PHA level and composition in waste activated sludge (WAS) on hydrogen production. The results showed that with the increase of sludge PHA content from 25 to 178mg per gram volatile suspended solids (VSS) hydrogen production from WAS alkaline anaerobic fermentation increased from 26.5 to 58.7mL/g VSS. The composition of PHA was also found to affect hydrogen production. When the dominant composition shifted from polyhydroxybutyrate (PHB) to polyhydroxyvalerate (PHV), the amount of generated hydrogen decreased from 51.2 to 41.1mL/g VSS even under the same PHA level (around 130mg/g VSS). The mechanism studies exhibited that the increased PHA content accelerated both the cell solubilization and the hydrolysis process of solubilized substrates. Compared with the PHB-dominant sludge, the increased PHV fraction not only slowed the hydrolysis process but also caused more propionic acid production, with less theoretical hydrogen generation in this fermentation type. It was also found that the increased PHA content enhanced the soluble protein conversion of non-PHA biomass. Further investigations with enzyme analyses showed that both the key hydrolytic enzyme activities and hydrogen-forming enzyme activities were in the sequence of the PHB-dominant sludge>the PHV-dominant sludge>the low PHA sludge, which was in accord with the observed order of hydrogen yield.
Formatted abstract
Polyhydroxyalkanoates (PHA), an intracellular energy and carbon storage polymer, can be accumulated in activated sludge in substantial quantities under wastewater dynamic treatment (i.e., substrate feast-famine) conditions. However, its influence on hydrogen production has never been investigated before. This study therefore evaluated the influences of PHA level and composition in waste activated sludge (WAS) on hydrogen production. The results showed that with the increase of sludge PHA content from 25 to 178 mg per gram volatile suspended solids (VSS) hydrogen production from WAS alkaline anaerobic fermentation increased from 26.5 to 58.7 mL/g VSS. The composition of PHA was also found to affect hydrogen production. When the dominant composition shifted from polyhydroxybutyrate (PHB) to polyhydroxyvalerate (PHV), the amount of generated hydrogen decreased from 51.2 to 41.1 mL/g VSS even under the same PHA level (around 130 mg/g VSS). The mechanism studies exhibited that the increased PHA content accelerated both the cell solubilization and the hydrolysis process of solubilized substrates. Compared with the PHB-dominant sludge, the increased PHV fraction not only slowed the hydrolysis process but also caused more propionic acid production, with less theoretical hydrogen generation in this fermentation type. It was also found that the increased PHA content enhanced the soluble protein conversion of non-PHA biomass. Further investigations with enzyme analyses showed that both the key hydrolytic enzyme activities and hydrogen-forming enzyme activities were in the sequence of the PHB-dominant sludge > the PHV-dominant sludge > the low PHA sludge, which was in accord with the observed order of hydrogen yield.
Keyword Biological nutrient removal
Dark fermentation
Hydrogen production from waste activated sludge
Polyhydroxyalkanoates
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
Advanced Water Management Centre Publications
 
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