title: Influence of water quality on nitrifier regrowth in two full-scale drinking water distribution systems.
abstract: The potential for regrowth of nitrifying microorganisms was monitored in 2 full-scale chloraminated drinking water distribution systems in Ontario, Canada, over a 9-month period. Quantitative PCR was used to measure amoA genes from ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), and these values were compared with water quality parameters that can influence nitrifier survival and growth, including total chlorine, ammonia, temperature, pH, and organic carbon. Although there were no severe nitrification episodes, AOB and AOA were frequently detected at low concentrations in samples collected from both distribution systems. A culture-based presence-absence test confirmed the presence of viable nitrifiers. AOB were usually present in similar or greater numbers than AOA in both systems. As well, AOB showed higher regrowth potential compared with AOA in both systems. Statistically significant correlations were measured between several water quality parameters of relevance to nitrification. Total chlorine was negatively correlated with both nitrifiers and heterotrophic plate count (HPC) bacteria, and ammonia levels were positively correlated with nitrifiers. Of particular importance was the strong correlation between HPC and AOB, which reinforced the usefulness of HPC as an operational parameter to measure general microbiological conditions in distribution systems.
authors.affiliation: NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.|NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Scott
authors.affiliation: NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.|NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
authors.forename: Michele I
authors.initials: MI
authors.lastname: Van Dyke
authors.affiliation: NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.|NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
authors.forename: William B
authors.initials: WB
authors.lastname: Anderson
authors.affiliation: NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.|NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Huck
mesh_terms: D000641:Ammonia / Q000378:metabolism; D001105:Archaea / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism; D002170:Canada; D060766:Drinking Water / Q000737:chemistry / Q000382:microbiology*; D058465:Nitrification; D009864:Ontario; D010084:Oxidation-Reduction; D060753:Water Quality
chemical_list: D060766:Drinking Water; D000641:Ammonia
keywords: ammonia-oxidizing archaea; ammonia-oxidizing bacteria; archéens oxydant l’ammoniac; bactéries oxydant l’ammoniac; chloramine; distribution system; drinking water; eau potable; nitrifia; nitrifier; système de distribution