水研究(WATER RESEARCH )2013-09-05 2:58 AM

Monochloramine cometabolism by Nitrosomonas europaea under drinking water conditions

Chloramine is widely used in United States drinking water systems as a secondary disinfectant, which may promote the growth of nitrifying bacteria because ammonia is present. At the onset of nitrification, both nitrifying bacteria and their products exert a monochloramine demand, decreasing the residual disinfectant concentration in water distribution systems. This work investigated another potentially significant mechanism for residual disinfectant loss: monochloramine cometabolism by ammonia-oxidizing bacteria (AOB). Monochloramine cometabolism was studied with the pure culture AOB Nitrosomonas europaea (ATCC 19718) in batch kinetic experiments under drinking water conditions. Three batch reactors were used in each experiment: a positive control to estimate the ammonia kinetic parameters, a negative control to account for abiotic reactions, and a cometabolism reactor to estimate the cometabolism kinetic constants. Kinetic parameters were estimated in AQUASIM with a simultaneous fit to all experimental data. The cometabolism reactors showed a more rapid monochloramine decay than in the negative controls, demonstrating that cometabolism occurs. Cometabolism kinetics were best described by a pseudo first order model with a reductant term to account for ammonia availability. Monochloramine cometabolism kinetics were similar to those of ammonia metabolism, and monochloramine cometabolism was a significant loss mechanism (30–60% of the observed monochloramine decay). These results suggest that monochloramine cometabolism should occur in practice and may be a significant contribution to monochloramine decay during nitrification episodes in drinking water distribution systems.

KEYWORDS

SHARE & LIKE

COMMENTS

ABOUT THE AUTHOR

水研究(WATER RESEARCH )

0 Following 1 Fans 0 Projects 5 Articles

SIMILAR ARTICLES

Water and wastewater treatment and conveyance account for approximately 4% of US electric consumption, with 80% used for conveyance. Net zero water (NZ

Read More

Ammonia oxidation by Nitrosomonas europaea, an ammonia oxidizing bacterium prevalent in wastewater treatment, is inhibited in the presence of phenol, d

Read More

Olive milling produces huge amounts of wastewater (OMWW) characterized by an extremely high organic load. Its polyphenols content is a hindrance to con

Read More

We compared the prevalence of pathogenic and extended-spectrum beta-lactamase (ESBL) – producing Escherichia coli in effluents of a municipal wastewate

Read More

Chloramine is widely used in United States drinking water systems as a secondary disinfectant, which may promote the growth of nitrifying bacteria beca

Read More