title: Enhancement of solubilization and acidification of waste activated sludge by pretreatment.
abstract: The effects of various pretreatment methods, including thermo-acid, thermo-alkaline, ultrasonic-alkaline and ultrasonic-acid, on solubilization and subsequent acidification efficiency of waste activated sludge (WAS) were investigated. The results showed that both thermo-alkaline and ultrasonic-alkaline significantly improved the solubilization of WAS at a high concentration (7.4% of total solids). Solubilization of volatile solids (VS) and crude protein was 60.2-61.6% and 66.8-67.5%, respectively. Thermo-alkaline or ultrasonic-alkaline pretreatment also enhanced the efficiency of subsequent WAS acidification. Experimental results showed that they had similar effects on the acidification of WAS. The conversion ratio from VS to total volatile fatty acids (TVFAs) was 0.230 in the case of the ultrasonic-alkaline pretreatment. Through this pretreatment, the level of TVFAs was 68% more than the untreated WAS after 252 h of fermentation. The mechanism of TVFAs production under different pretreatment methods was further investigated and the results indicated that soluble protein was the main substrate for TVFAs production from the WAS after the thermo-alkaline or ultrasonic-alkaline pretreatment.
authors.affiliation: School of Biotechnology, Southern Yangtze University, 1800 Lihu Road, Wuxi 214122, Jiangsu Province, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Liu
authors.forename: He
authors.initials: H
authors.lastname: Liu
authors.forename: Jinhuan
authors.initials: J
authors.lastname: Chen
authors.forename: Guocheng
authors.initials: G
authors.lastname: Du
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
mesh_terms: D006863:Hydrogen-Ion Concentration; D008854:Microscopy, Electron; D012722:Sewage / Q000737:chemistry*; D012995:Solubility; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D012722:Sewage; D014874:Water Pollutants, Chemical