TITLE:
Enhanced Biohydrogen Production by Accelerating the Hydrolysis of Macromolecular Components of Waste Activated Sludge Using TiO2 Photocatalysis as a Pretreatment
AUTHORS:
Dawei Li, Yingxin Zhao, Qinghong Wang, Yingnan Yang, Zhenya Zhang
KEYWORDS:
Waste Activated Sludge; TiO2 Photocatalytic Retreatment; Macromolecular Components; Hydrolysis
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.3 No.2,
June
19,
2013
ABSTRACT:
The effects of TiO2 photocatalysis on the hydrolysis of
protein of waste activated sludge (WAS) and its biodegradability were
investigated in this study. After 12-h UV irradiation, the removal ratio of
protein by TiO2 photocatalysis reached 98.1%. The optimal condition
for photocatalytic degradation of protein is TiO2 dosage of 5.0 mg·L–1 under 2.4 w·m–2 UV light irradiation. TiO2 photocatalysis
in comparison with other pretreatments obviously accelerated the hydrolysis of
WAS and improved the conversion of total COD (tCOD) to soluble COD (sCOD). The
sCOD/tCOD ratio of WAS pretreated by TiO2 photocatalysis, UV
photolysis and TiO2 adsorption and that of the control were 92.8%,
32.5%, 18.0% and 16.6%, respectively. TiO2 photocatalytic
pretreatment accelerated the biohydrogen production from 10-fold diluted WAS.
The bioreactors containing UV photolysis and TiO2 adsorption
pretreated WASs and the control reactor require 0.5-d, 0.9-d and 0.7-d start-up
period for biohydrogen production, respectively. While the bioreactor containing
TiO2 photocatalysis pretreated WAS obtained a hydrogen yield of 0.5
mL-H2/g-VS merely after 0.5-d mesophilic fermentation. The cumulative
biohydrogen production from TiO2 photocatalysis pretreated WAS
during 4-d mesophilic fermentation reached 11.7 mL-H2/g-VS, which
was 1.2 times higher than that from the control. TiO2 photocatalytic
pretreatment enhanced the biohydrogen production from WAS via accelerating the
hydrolysis of its macromolecular components to smaller molecule weight
hydrolysates.