NDMA and Other Nitrosamines: Precursor Control, Treatment Practices and Distribution System Operations to Achieve Regulatory Compliance
Chloramines have been replacing chlorine as a secondary disinfectant as a cost-effective means to comply with stricter trihalomethane (THMs) and haloacetic acid (HAA) regulations. Chloramines have been shown to minimize the formation of THMs and HAAs, but they favor the formation of N-nitrosodimethylamine (NDMA), the most frequently detected nitrosamine. Also, increased contributions to source waters from treated wastewater discharges have led to elevated levels of nitrosamine precursors. Moreover, the commonly used polymer polyDADMAC and certain anion exchange resins are a source of nitrosamines or their precursors. Recent research indicates that certain materials in the distribution system may be a source of nitrosamines or their precursors.
In 2012, WRF initiated this Research Area to provide information to regulatory agencies and prepare water utilities for potential regulations. A comprehensive multi-year research agenda was developed that consisted of projects covering occurrence, formation, precursor identification, and control strategies.
Research Area Objectives
- Investigate the contribution of source water quality, treatment processes, and distributions system operations to the total pool of nitrosamine precursors
- Develop control strategies to prevent or minimize the formation of nitrosamines from source to tap
- Identify unintended consequences and cost of compliance
Research Area Project Timeline and Value
Investigating Alternative Coagulant Aids to PolyDADMAC
- Timeline: 2012–2015
- Total Project Value: $540,670
- Research Area Objectives: Precursors, Treatment, Other
- Timeline: 2013–2016
- Total Project Value: $611,902
- Research Area Objectives: Occurrence, Precursors
Unintended Consequences of Implementing Nitrosamine Control Strategies
- Timeline: 2013–2017
- Total Project Value: $376,710
- Research Area Objectives: Occurrence, Precursors, Treatment, Other
Relative Importance and Contribution of Anthropogenic and Natural Sources of Nitrosamine Precursors
- Timeline: 2014–2017
- Total Project Value: $433,564
- Research Area Objectives: Occurrence, Treatment
Effect of GAC on the Removal of DBPs of Health Concern
- Timeline: 2014–2018
- Total Project Value: $697,709
- Research Area Objectives: Occurrence, Precursors, Treatment, Other
Understanding the Source and Fate of Polymer-Derived Nitrosamine Precursors
- Timeline: 2015–2018
- Total Project Value: $531,456
- Research Area Objectives: Precursors, Treatment, Other
Biological Treatment: NDMA Control of Sources of Precursors
- Timeline: 2016–2019
- Total Project Value: $554,583
- Research Area Objectives: Precursors, Treatment
Cumulative Project Value for Research Area: $3,746,594
Projects Funded Outside of the Research Area Program that meet a Research Area Objective
Controlling the Formation of Nitrosamines During Water Treatment
- Year Completed: 2015
- Funding Program: RAC
- RA Objectives: Treatment
Seasonal Changes in NDMA Formation Potential and its Removal During Water Treatment
- Year Completed: 2016
- Funding Program: TC
- RA Objectives: Precursors, Treatment
Major Sources of Nitrosamine Precursors in Raw Waters
- Year Completed: 2017
- Funding Program: TC
- RA Objectives: Precursors, Treatment
Key
RAC = Research Area Council
TC = Tailored Collaboration