Effect of free ammonia concentration on monochloramine penetration within a nitrifying biofilm and its effect on activity, viability, and recovery

Pressman, Jonathan G.; Lee, Woo Hyoung; Bishop, Paul L.; Wahman, David G.

doi:10.1016/j.watres.2011.11.071

Cited by 50 publications

(42 citation statements)

References 36 publications

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“…Biofilm formation allows for aerobic bacteria to increase their resilience to disinfectant residuals. This resilience is further increased with the presence of free ammonia in chloraminated systems [52]. Biofilms harbor, and facilitate the growth of, nitrifying bacteria and can promote nitrification in DWDS [36,53].…”

Section: Microbiology Of Nitrificationmentioning

confidence: 99%

Nitrification in Premise Plumbing: A Review

Bradley

Haas

Sales

2020

Water

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Nitrification is a major issue that utilities must address if they utilize chloramines as a secondary disinfectant. Nitrification is the oxidation of free ammonia to nitrite which is then further oxidized to nitrate. Free ammonia is found in drinking water systems as a result of overfeeding at the water treatment plant (WTP) or as a result of the decomposition of monochloramine. Premise plumbing systems (i.e., the plumbing systems within buildings and homes) are characterized by irregular usage patterns, high water age, high temperature, and high surface-to-volume ratios. These characteristics create ideal conditions for increased chloramine decay, bacterial growth, and nitrification. This review discusses factors within premise plumbing that are likely to influence nitrification, and vice versa. Factors influencing, or influenced by, nitrification include the rate at which chloramine residual decays, microbial regrowth, corrosion of pipe materials, and water conservation practices. From a regulatory standpoint, the greatest impact of nitrification within premise plumbing is likely to be a result of increased lead levels during Lead and Copper Rule (LCR) sampling. Other drinking water regulations related to nitrifying parameters are monitored in a manner to reduce premise plumbing impacts. One way to potentially control nitrification in premise plumbing systems is through the development of building management plans.

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Section: Microbiology Of Nitrificationmentioning

confidence: 99%

Nitrification in Premise Plumbing: A Review

Bradley

Haas

Sales

2020

Water

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“…Microelectrodes with small tip diameters (e.g., 5 to 10 μm) have been utilized to understand biofilm activity in various aqueous systems through profiling chemical concentrations within the biofilm's microscopic space without disrupting its structure [4]. For example, they have been used for evaluation of biofilm disinfection with the goal of improving biofilm control strategies in drinking water distribution systems [5,6].…”

Section: Introductionmentioning

confidence: 99%

Monochloramine-sensitive amperometric microelectrode: optimization of gold, platinum, and carbon fiber sensing materials for removal of dissolved oxygen interference

Lee

Wahman

Pressman

2015

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Monochloramine electrochemical determination in an aqueous system using newly fabricated gold and platinum microelectrodes was investigated to optimize sensor operation and to eliminate dissolved oxygen (DO) interference during monochloramine measurements. Carbon fiber microelectrodes were also compared for reference purposes. Gold and platinum microelectrodes exhibited no oxygen interference during monochloramine measurement and provided a linear relationship when operated at +150 and +300 mV vs. Ag/ AgCl over a wide concentration range (0-4.2 mg Cl 2 /L), respectively. The carbon fiber microelectrode with 7-μm tip diameter was not sufficiently sensitive to monochloramine concentrations for detailed study. The baseline signal of both gold and platinum microelectrodes (i.e., signal without monochloramine) was near zero. With the same geometric tip diameter (20-μm tip diameter), gold microelectrodes resulted in better amperometric electrode response to monochloramine than platinum microelectrodes; gold microelectrodes had a higher sensitivity (52±0.7 vs. 18±0.07 pA/ [mg Cl 2 /L]) and lower detection limit (0.12±0.013 vs. 0.33± 0.10 mg Cl 2 /L), resulting in gold as the preferred microelectrode material. The developed gold microelectrode will allow accurate in situ monochloramine determination in biofilm while eliminating the confounding effects of oxygen interference.

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“…In studies where monochloramine was applied to a nitrifying biofilm, Lee et al (2011) reported monochloramine application impacted biofilm metabolic activity (based on dissolved oxygen [DO] consumption) within 30 min; whereas, based on cell membrane integrity, minimal biofilm inactivation was seen at 2 h. Furthermore, during monochloramine cometabolism experiments with N. europaea, Maestre et al (2013) found that ammonia oxidation quickly ceased while cell membrane integrity remained. Inactivation rates have been reported to increase in the following order: (i) cell membrane integrity (Oldenburg et al, 2002;Wahman et al, 2010Wahman et al, , 2009), (ii) culturability (Oldenburg et al, 2002), and (iii) metabolic activity (Lee et al, 2011;Maestre et al, 2013;Pressman et al, 2012). Direct monochloramine cellular reactions (Pathway A, Fig.…”

Section: Introductionmentioning

confidence: 99%