EPA Science Inventory

Monochloramine Cometabolism by Nitrosomonas europaea under Drinking Water Conditions

Citation:

Maestre, J. P., D. G. Wahman, AND G. E. Speitel Jr. Monochloramine Cometabolism by Nitrosomonas europaea under Drinking Water Conditions. WATER RESEARCH. Elsevier Science Ltd, New York, NY, 47(13):4701-4709, (2013).

Description:

Chloramine use is widespread in United States drinking water systems as a secondary disinfectant. While beneficial from the perspective of controlling disinfectant by-product formation, chloramination 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 system models.

Purpose/Objective:

Research related to study nitrification in drinking water distribution systems

URLs/Downloads:

http://dx.doi.org/10.1016/j.watres.2013.05.019   Exit

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Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Start Date: 09/01/2013
Completion Date: 09/01/2013
Record Last Revised: 02/12/2014
Record Created: 02/06/2014
Record Released: 02/06/2014
OMB Category: Other
Record ID: 268256

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL RISK MANAGEMENT RESEARCH LABORATORY

WATER SUPPLY AND WATER RESOURCES DIVISION

TREATMENT TECHNOLOGY EVALUATION BRANCH