title: Hydrolysis, acidification and dewaterability of waste activated sludge under alkaline conditions: combined effects of NaOH and Ca(OH)2.
abstract: Hydrolysis, acidification and dewaterability of waste activated sludge (WAS) were investigated at pH 10 controlled by the addition of NaOH, Ca(OH)2 or their mixtures at various ratios. Similar efficiency of WAS solublisation was observed in all cases, at 38-40%. High volatile fatty acid (VFA) production and good sludge dewaterability could not be achieved simultaneously by adding NaOH or Ca(OH)2 alone, but could be achieved by adding mixtures of NaOH and Ca(OH)2. VFA production in the case with the addition of Ca(OH)2 only (1201 mg(COD)/L) was lower than in the cases with the addition of NaOH or its mixtures with Ca(OH)2 (1813-1868 mg(COD)/L), and the lower VFA production with Ca(OH)2 addition alone could be related to the fact that a higher concentration of Ca(2+) was released into the fermentation liquid, which likely inhibited the hydrolysis process of protein. Furthermore, adding mixtures of NaOH and Ca(OH)2 was more economical for VFA production.
authors.affiliation: Key Laboratory of Beijing Water Quality Science and Water Environment Recovery Engineering, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China. sugaoqiang1985@emails.bjut.edu.cn
authors.forename: Gaoqiang
authors.initials: G
authors.lastname: Su
authors.forename: Mingxin
authors.initials: M
authors.lastname: Huo
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yuan
authors.forename: Shuying
authors.initials: S
authors.lastname: Wang
authors.forename: Yongzhen
authors.initials: Y
authors.lastname: Peng
mesh_terms: D000143:Acids / Q000378:metabolism*; D002118:Calcium / Q000032:analysis; D002126:Calcium Hydroxide / Q000737:chemistry*; D002241:Carbohydrates / Q000032:analysis; D003365:Costs and Cost Analysis; D005232:Fatty Acids, Volatile / Q000032:analysis; D005285:Fermentation; D006868:Hydrolysis; D011506:Proteins / Q000032:analysis; D012722:Sewage / Q000737:chemistry*; D012964:Sodium / Q000032:analysis; D012972:Sodium Hydroxide / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000378:metabolism*
chemical_list: D000143:Acids; D002241:Carbohydrates; D005232:Fatty Acids, Volatile; D011506:Proteins; D012722:Sewage; D014867:Water; D012972:Sodium Hydroxide; D012964:Sodium; D002126:Calcium Hydroxide; D002118:Calcium