US EPA

4245584 

Journal Article 

N-nitrosodimethylamine (NDMA) formation from the ozonation of model compounds 

Marti, EJ; Pisarenko, AN; Peller, JR; Dickenson, ER 

2015 

1 

Water Research
ISSN: 0043-1354
EISSN: 1879-2448 

Elsevier Ltd 

72 

262-270 

English 

25241951 

10.1016/j.watres.2014.08.047 

WOS:000353605000020 

Nitrosamines are a class of toxic disinfection byproducts commonly associated with chloramination, of which several were included on the most recent U.S. EPA Contaminant Candidate List. Nitrosamine formation may be a significant barrier to ozonation in water reuse applications, particularly for direct or indirect potable reuse, since recent studies show direct formation during ozonation of natural water and treated wastewaters. Only a few studies have identified precursors which react with ozone to form N-nitrosodimethylamine (NDMA). In this study, several precursor compound solutions, prepared in ultrapure water and treated wastewater, were subjected to a 10 M excess of ozone. In parallel experiments, the precursor solutions in ultrapure water were exposed to gamma radiation to determine NDMA formation as a byproduct of reactions of precursor compounds with hydroxyl radicals. The results show six new NDMA precursor compounds that have not been previously reported in the literature, including compounds with hydrazone and carbamate moieties. Molar yields in deionized water were 61-78% for 3 precursors, 12-23% for 5 precursors and <4% for 2 precursors. Bromide concentration was important for three compounds (1,1-dimethylhydrazine, acetone dimethylhydrazone and dimethylsulfamide), but did not enhance NDMA formation for the other precursors. NDMA formation due to chloramination was minimal compared to formation due to ozonation, suggesting distinct groups of precursor compounds for these two oxidants. Hydroxyl radical reactions with the precursors will produce NDMA, but formation is much greater in the presence of molecular ozone. Also, hydroxyl radical scavenging during ozonation leads to increased NDMA formation. Molar conversion yields were higher for several precursors in wastewater as compared to deionized water, which could be due to catalyzed reactions with constituents found in wastewater or hydroxyl radical scavenging. 

Disinfection byproduct; N-Nitrosodimethylamine; NDMA; Nitrosamine; Ozone; Potable reuse; Acetone; Amination; Byproducts; Deionized water; Disinfection; Nitrosamines; Ozone; Ozonization; Potable water; Reaction kinetics; Wastewater reclamation; Wastewater treatment; Water conservation; Water distribution systems; Water treatment; Catalyzed reactions; Disinfection by-product; Hydroxyl radical reactions; Indirect potable reuse; N-nitrosodimethylamine; NDMA; Potable reuse; Precursor solutions; Ozone water treatment; 1,1 dimethylhydrazine; acetone; bromide; carbamic acid; dimethylnitrosamine; hydrazone derivative; hydrogen peroxide; hydroxyl radical; ozone; sulfamide derivative; water; bromide; buffer; chloramine derivative; dimethylnitrosamine; oxidizing agent; waste water; water pollutant; catalysis; concentration (composition); disinfection; hydroxyl radical; ozone; water management; water quality; water use; Article; gamma radiation; ozonation; ozonolysis; priority journal; waste water management; water quality; analysis; chemistry; waste water; water pollutant; United States; Bromides; Buffers; Chloramines; Dimethylnitrosamine; Hydrogen Peroxide; Oxidants; Ozone; Waste Water; Water Pollutants, Chemical