Author(s)

Dawei Li, Yingxin Zhao, Qinghong Wang, Yingnan Yang, Zhenya Zhang

College of Chemical Engineering, China University of Petroleum, Beijing, China.
Graduate School of Life and Environmental Science, University of Tsukuba, Tsukuba, Japan.

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.

Waste Activated Sludge; TiO₂ Photocatalytic Retreatment; Macromolecular Components; Hydrolysis

D. Li, Y. Zhao, Q. Wang, Y. Yang and Z. Zhang, "Enhanced Biohydrogen Production by Accelerating the Hydrolysis of Macromolecular Components of Waste Activated Sludge Using TiO₂ Photocatalysis as a Pretreatment," Open Journal of Applied Sciences, Vol. 3 No. 2, 2013, pp. 155-162. doi: 10.4236/ojapps.2013.32021.