title: Effects of inorganic nutrients on the regrowth of heterotrophic bacteria in drinking water distribution systems.
abstract: Three laboratory-scale water pipe systems were set up to study the effects of adding three inorganic nutrients (ammonium, nitrate or phosphate) on biofilm formation in water pipes. The results showed that the effects of adding ammonium or nitrate on the biofilm formation were insignificant when levels below 0.1 mg N/l were added. Analogous results were observed when phosphate was added at levels below 0.005 mgP/l. However, as the addition of ammonium increased to 0.5 mgN/l, significant effects on biofilm formation were observed. Similar results were obtained phosphate was added at levels above 0.01 mgP/l. Batch tests were also conducted using water samples collected from a Taiwanese drinking water distribution system. The results indicated that the addition of ammonium, nitrate or phosphate to treatment plant effluent stimulates bacterial growth. In the distributed water of an urban area, the addition of nitrate or phosphate stimulated bacterial growth. The bacterial growth in the distributed water of a suburban area was not stimulated by adding any of these three inorganic nutrients.
authors.affiliation: Department of Environmental Engineering, National Chung Hsing University, 250, Kuo Kuang Road, Taichung 402, Taiwan, ROC.
authors.forename: Chenghwa
authors.initials: C
authors.lastname: Chu
authors.forename: Chungsying
authors.initials: C
authors.lastname: Lu
authors.forename: Chimei
authors.initials: C
authors.lastname: Lee
mesh_terms: D001419:Bacteria / Q000254:growth & development*; D018441:Biofilms / Q000254:growth & development*; D009566:Nitrates / Q000494:pharmacology; D010710:Phosphates / Q000494:pharmacology; D011157:Population Dynamics; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D014871:Water Microbiology; D014881:Water Supply / Q000592:standards*
chemical_list: D009566:Nitrates; D010710:Phosphates; D000644:Quaternary Ammonium Compounds