title: Release of organic matter in a discontinuously chlorinated drinking water network.
abstract: The effects of discontinuous chlorination on the characteristics of the water in a pilot drinking water distribution network were investigated. The release or consumption of organic matter (as dissolved organic carbon, DOC) following chlorination and non-chlorination periods were estimated, as were changes in bacterial cell production. In each unchlorinated network 0.3 mg DOCl(-1) was consumed and the average cell production was approximately 1.3 x 10(5) cells ml(-1). In discontinously chlorinated networks (chlorine treatment: 3.3 mg Cl2l(-1), chlorine residual: 0.1 mg Cl2l(-1)) the DOC release (DOCout-DOCin) was between 0.1 and 0.2 mg Cl(-1). Biomass production (cells(out)-cells(in)) during this chlorination period was lower (approximately 2 x 10(4) cells ml(-1)). The delay before DOC was released in chlorinated networks appeared to be less than 24 h, which corresponds to one hydraulic residence time. Likewise, when chlorination was stopped, 24 h or less were required before an efficient DOC removal was resumed. When chlorination was prolonged the observed release of DOC was progressively reduced from 0.2 mg l(-1) to zero, thus after 6 weeks of continuous chlorination the DOCin was equivalent to the DOCout.
authors.affiliation: NANCIE, 149 rue Gabriel Péri, BP 290, F-54515 Vandaeuvre-lès-Nancy, France.
authors.forename: S
authors.initials: S
authors.lastname: Fass
authors.forename: J C
authors.initials: JC
authors.lastname: Block
authors.forename: M
authors.initials: M
authors.lastname: Boualam
authors.forename: V
authors.initials: V
authors.lastname: Gauthier
authors.forename: D
authors.initials: D
authors.lastname: Gatel
authors.forename: J
authors.initials: J
authors.lastname: Cavard
authors.forename: S
authors.initials: S
authors.lastname: Benabdallah
authors.forename: V
authors.initials: V
authors.lastname: Lahoussine
mesh_terms: D018441:Biofilms; D002244:Carbon / Q000032:analysis*; D017606:Chlorine Compounds / Q000032:analysis / Q000737:chemistry*; D009930:Organic Chemicals / Q000032:analysis; D014872:Water Movements; D018508:Water Purification; D014881:Water Supply
chemical_list: D017606:Chlorine Compounds; D009930:Organic Chemicals; D002244:Carbon