Formation and Removal of NDMA in Water
Recycling Systems
N-Nitrosodimethylamine (NDMA) is a potent
carcinogen that has been detected after chlorine disinfection of
municipal wastewater. In water from advanced treatment plants used for
indirect potable reuse, the concentration of NDMA frequently exceeds
the action level set by the California
Department of Health Services
(Cal DHS). The presence of NDMA in recycled water has led to the
closure of drinking water wells in Southern California and has led to
serious concerns among practitioners of water reuse.
To control NDMA engineers need a better
understanding of how NDMA is formed and how it can be removed.
Laboratory studies conducted as part of Bill Mitch's doctoral research
showed that NDMA can form through a reaction between
monochloramine (a form of chlorine commonly found during disinfection)
and simple amines, such as dimethylamine (Mitch and Sedlak, 2002).
We also learned that the NDMA precursors consisted of low
molecular weight nitrogen-containing compounds that were difficult to
remove during conventional and advanced treatment processes (Mitch and
Sedlak, 2004).
More recently we have been studying the fate
of
NDMA precursors in systems where wastewater effluent has the potential
to enter potable water supplies. For example, as part of her
doctoral research, Elif Phelivanoglu showed that the NDMA precursors
were stable for over a month in the presence of bacteria isolated form
activated sludge wastewater treatment plants (Figure 1). The
relative stability of the precursors implies that NDMA may be formed
when effluent-dominated rivers are used as water supplies.
Our ongoing research is focused on identifying mechanisms
through
which NDMA precursors can be removed during groundwater infiltration.
Figure 1: Fate of NDMA precursors during
incubation in the presence of bacteria.
For more information see:
Pehlivanoglu-Mantas E., Hawley E.L., Deeb R.A. and Sedlak D.L. (2006) Formation of nitrosodimethylamine (NDMA) during chlorine disinfection of wastewater effluents prior to use in irrigation systems. Water Research, 40, 341-347.
Pehlivanoglu-Mantas E. and Sedlak D.L. (2006) The fate of wastewater-derived NDMA precursors in the aquatic environment
Water Research, 40, 1287-123.
Gan J., Bondarenko S., Ernst F., Yang W., Ries S.B., Sedlak D.L. (2006)
Leaching of N-nitrosodimethylamine (NDMA) in turfgrass soils during
wastewater irrigation. Journal of Environmental Quality, 35, 277-284.
Arienzo M., Gan J., Ernst F., Qin S., Bondarenko S., Sedlak D.L. (2006)
Loss pathways of N-nitrosodimethylamine (NDMA) in turfgrass soils
Journal of Environmental Quality, 35, 285-292.
Removal and Destruction of NDMA and NDMA Precursors during Wastewater Treatment. Final Report to the WateReuse Foundation, Project 01-002.
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The Fate of
Hormones in the Aquatic Environment
Pharmaceutically-Active
Compounds in Aquatic Systems
Formation and
Removal of NDMA in Water Recycling Systems
Oxidation of Contaminants by Iron
Nanoparticles in the Presence of Oxygen
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