title: Variation of dissolved organic nitrogen concentration during the ultrasonic pretreatment to Microcystis aeruginosa.
abstract: Algae cells were the main sources of dissolved organic nitrogen (DON) in raw water with plenty of algae, and ultrasonic pretreatment was one of the algae-controlling methods through the damage of algae cells. However, the variation of DON concentration during the ultrasonic treatment process was not confirmed. Variation of DON concentration during the processes of low frequency ultrasound treatment of Microcystis aeruginosa was investigated. In addition, the effect of sonication on the metabolite concentration, algae cellar activity and the subsequent coagulation performance were discussed. The results showed that after a long duration of ultrasonic (60 s), nearly 90% of the algal cells were damaged and the maximum concentration of DON attained more than 3 mg/L. In order to control the leakage extent of DON, the sonication time should be less than 30 s with power intensity of more than 1.0 W/cm(3). In the mean time, ultrasonic treatment could inhibit the reactivation and the proliferation of algal, keep the algae cell wall integrity and enhance coagulation effectively under the same condition. However, ultrasound frequency had little effect on DON at the frequency range used in this study (20-150 kHz).
authors.affiliation: Key Laboratory of Integrated Regulation and Resource Development Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; Environmental College, Hohai University, Nanjing 210098, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Liu
authors.affiliation: Key Laboratory of Integrated Regulation and Resource Development Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.affiliation: Environmental College, Hohai University, Nanjing 210098, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Cao
authors.affiliation: Key Laboratory of Integrated Regulation and Resource Development Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China. Electronic address: liucheng8791@sina.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Pathogenic Biology, Jiangsu Key Laboratory of Pathogenic Biology, Nanjing Medical University, Nanjing 210029, China; Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Hongkai
authors.initials: H
authors.lastname: Bi
mesh_terms: D000818:Animals; D046931:Microcystis / Q000378:metabolism*; D009584:Nitrogen / Q000737:chemistry* / Q000378:metabolism*; D009812:Odorants; D013997:Time Factors; D000069453:Ultrasonic Waves / Q000009:adverse effects*; D060753:Water Quality
chemical_list: D009584:Nitrogen
keywords: Algal; Dissolved organic nitrogen; Drinking water; Enhanced coagulation; Ultrasonic pretreatment