title: Insight into the short- and long-term effects of Cu(II) on denitrifying biogranules.
abstract: This study aimed to investigate the short- and long-term effects of Cu(2+) on the activity and performance of denitrifying bacteria. The short-term effects of various concentrations of Cu(2+) on the denitrifying bacteria were evaluated using batch assays. The specific denitrifying activity (SDA) decreased from 14.3 ± 2.2 (without Cu(2+)) to 6.1 ± 0.1 mg N h(-1)g(-1) VSS (100 mg Cu(2+)L(-1)) when Cu(2+) increased from 0 to 100 mg L(-1) with an increment of 10 mg Cu(2+)L(-1). A non-competitive inhibition model was used to calculate the 50% inhibition concentration (IC50) of Cu(2+) on denitrifying sludge (30.6 ± 2.5 mg L(-1)). Monod and Luong models were applied to investigate the influence of the initial substrate concentration, and the results suggested that the maximum substrate removal rate would be reduced with Cu(2+) supplementation. Pre-exposure to Cu(2+) could lead to an 18.2-46.2% decrease in the SDA and decreasing percentage of the SDA increased with both exposure time and concentration. In the continuous-flow test, Cu(2+) concentration varied from 1 to 75 mg L(-1); however, no clear deterioration was observed in the reactor, and the reactor was kept stable, with the total nitrogen removal efficiency and total organic carbon efficiency greater than 89.0 and 85.0%, respectively. The results demonstrated the short-term inhibition of Cu(2+) upon denitrification, and no notable adversity was observed during the continuous-flow test after long-term acclimation.
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Qian-Qian
authors.initials: QQ
authors.lastname: Chen
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Jiang
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Hu
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Man-Ling
authors.initials: ML
authors.lastname: Shi
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China. Electronic address: jrczju@aliyun.com.
authors.forename: Ren-Cun
authors.initials: RC
authors.lastname: Jin
mesh_terms: D001419:Bacteria / Q000187:drug effects; D018533:Biomass; D019149:Bioreactors; D003300:Copper / Q000633:toxicity*; D058440:Denitrification / Q000187:drug effects
chemical_list: D003300:Copper
keywords: Acclimation; Cu(2+) toxicity; Denitrifying biogranules; Kinetic models; Pre-exposure