title: [Inactivation of the chlorine-resistant bacteria isolated from the drinking water distribution system].
abstract: Inactivation experiments of seven strains of chlorine-resistant bacteria, isolated from a drinking water distribution system, were conducted with four kinds of disinfectants. All the bacteria showed high resistance to chlorine, especially for Mycobacterium mucogenicum. The CT value of 99.9% inactivation for M. mucogenicum, Sphingomonas sanguinis and Methylobacterium were 120 mg x (L x min)(-1), 7 mg x (L x min)(-1) and 4 mg x (L x min)(-1), respectively. The results of inactivation experiments showed that chlorine dioxide and potassium monopersulfate could inactive 5 lg of M. mucogenicum within 30 min, which showed significantly higher efficiency than free chlorine and monochloramine. Free chlorine was less effective because the disinfectant decayed very quickly. Chloramination needed higher concentration to meet the disinfection requirements. The verified dosage of disinfectants, which could effectively inactivate 99.9% of the highly chlorine-resistant M. mucogenicum within 1 h, were 3.0 mg/L monochloramine, 1.0 mg/L chlorine dioxide (as Cl2), and 1.0 mg/L potassium monopersulfate (as Cl2). It was suggested that the water treatment plants increase the concentration of monochloramine or apply chlorine dioxide intermittently to control the disinfectant-resistant bacteria.
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China. chenyq04@mails.tsinghua.edu.cn
authors.forename: Yu-Qiao
authors.initials: YQ
authors.lastname: Chen
authors.forename: Xiao-Di
authors.initials: XD
authors.lastname: Duan
authors.forename: Pin-Pin
authors.initials: PP
authors.lastname: Lu
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Xiao-Jian
authors.initials: XJ
authors.lastname: Zhang
authors.forename: Chao
authors.initials: C
authors.lastname: Chen
mesh_terms: D002700:Chloramines / Q000494:pharmacology; D002713:Chlorine / Q000494:pharmacology*; D017606:Chlorine Compounds / Q000494:pharmacology; D004202:Disinfectants / Q000494:pharmacology; D060766:Drinking Water / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D020580:Methylobacterium / Q000187:drug effects / Q000302:isolation & purification; D009161:Mycobacterium / Q000187:drug effects* / Q000302:isolation & purification; D010087:Oxides / Q000494:pharmacology; D020578:Sphingomonas / Q000187:drug effects* / Q000302:isolation & purification; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D002700:Chloramines; D017606:Chlorine Compounds; D004202:Disinfectants; D060766:Drinking Water; D010087:Oxides; D002713:Chlorine; C025109:chlorine dioxide; C030816:chloramine