title: The effects of changing water flow velocity on the formation of biofilms and water quality in pilot distribution system consisting of copper or polyethylene pipes.
abstract: We studied the effects of flow velocity on the formation of biofilms and the concentration of bacteria in water in copper and plastic (polyethylene, PE) pipes. The formation of biofilms increased with the flow velocity of water. The increase in microbial numbers and contents of ATP was clearer in the PE pipes than in the copper pipes. This was also seen as increased consumption of microbial nutrients in the pipeline system. This indicates that the mass transfer of nutrients is in major role in the growth of biofilms. However, the increased biomass of biofilms did not affect microbial numbers in the water. Rapid changes in water flow rate resuspended biofilms and sediments which increased the concentrations of bacteria and copper in water. The disturbance caused by the changing water flow was also seen as an increase in the particle counts and water turbidity recorded with online instrumentation.
authors.affiliation: Laboratory of Environmental Microbiology, National Public Health Institute, Department of Environmental Health, P.O. Box 95, FI-70701 Kuopio, Finland. Markku.Lehtola@ktl.fi
authors.forename: Markku J
authors.initials: MJ
authors.lastname: Lehtola
authors.forename: Michaela
authors.initials: M
authors.lastname: Laxander
authors.forename: Ilkka T
authors.initials: IT
authors.lastname: Miettinen
authors.forename: Arja
authors.initials: A
authors.lastname: Hirvonen
authors.forename: Terttu
authors.initials: T
authors.lastname: Vartiainen
authors.forename: Pertti J
authors.initials: PJ
authors.lastname: Martikainen
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D018533:Biomass; D003300:Copper / Q000737:chemistry*; D009391:Nephelometry and Turbidimetry; D010969:Plastics / Q000737:chemistry*; D020959:Polyethylene / Q000737:chemistry*; D011786:Quality Control; D012498:Sanitary Engineering; D014871:Water Microbiology; D014872:Water Movements; D014881:Water Supply / Q000032:analysis*
chemical_list: D010969:Plastics; D003300:Copper; D020959:Polyethylene