Controlling the Formation of Nitrosamines During Water Treatment

Project: Research project

Description

07/13/2011 HB: Meeting low ng/L nitrosamine regulatory levels will likely require an optimized combination of nitrosamine precursor removal upstream of disinfection with residual precursor deactivation by strong preoxidant disinfectants. The proposed research will employ the novel SDS and UFC tests to characterize this optimization under realistic operating conditions. Precursor removal processes to be evaluated include RBF, AC adsorption, magnetic ion exchange treatment (MIEX), as well as a reduction in polyDADAMCassociated precursors by optimizing the polymer dose or evaluating alternative polymers. Precursor oxidation processes will focus on chlorination, ozonation, and UV treatment, with some work with ClO2 and postassium permanganate (KMnO4). Results from WaterRF 4180 indicated that ozonation was generally the most effective at precursor destruction, followed by chlorination. Although UV treatment was less effective at precursor destruction, it is important to evaluate as incorporation of UV treatment is likely to grow to meet pathogen reduction goals. ClO2 will be pursued to a limited extent, as it was often one of the least effective pre-oxidants for precursor destruction, and in some cases may have promoted nitrosamine formation. In WaterRF 4180, we developed a good understanding of the relative efficacies of the different pre-oxidants, except for KMnO4 Task 1 - Preliminary case studies on nitrosamine formation and control at full-scale DWTPs . In addition to addressing outstanding issues on pre-oxidation of precursors in isolation, this research will evaluate combinations of precursor removal and pre-oxidation under realistic operating conditions. Lastly, this research will provide an initial economic evaluation of these treatment options and a decision document. The objectives of this project are to develop costeffective strategies for minimizing nitrosamine formation during drinking water treatment, while meeting other regulatory and operational requirements, and to develop treatment guidance for utilities. Through bench- and pilot-testing and full-scale case studies, the project objectives will be achieved by organization of the project approach around the following research tasks: Task 2 - Optimization of oxidation strategies for nitrosamine and regulated DBP control Task 3 - Optimizing polymer usage for nitrosamine and turbidity control Task 4 - Removing nitrosamine precursors from water Task 5 - Evaluating and controlling other sources of nitrosamines and their precursors Task 6 - Decision document and preliminary economic analysis of control options Details of these tasks are provided in a separate document. Below are the major roles for the ASU team.
StatusFinished
Effective start/end date2/1/125/1/15

Funding

  • EPA: Region 9: $115,000.00

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water treatment
oxidation
polymer
chlorination
oxidant
nitrosamine
formation water
economic analysis
disinfection
turbidity
ion exchange
pathogen
adsorption
economics
document
project
removal