N-Nitrosodimethylamine Formation upon Ozonation and Identification of Precursors Source in a Municipal Wastewater Treatment Plant

Abstract

Ozone doses normalized to the dissolved organic carbon concentration were applied to the primary influent, primary effluent, and secondary effluent of a wastewater treatment plant producing water destined for potable reuse. Results showed the most N-Nitrosodimethylamine (NDMA) production from primary effluent, and the recycle streams entering the primary clarifiers were identified as the main source of NDMA precursors. The degradation of aminomethylated polyacrylamide (Mannich) polymer used for sludge treatment was a significant cause of precursor occurrence. A strong correlation between NDMA formation and ammonia concentration was found suggesting an important role of ammonia oxidation on NDMA production. During ozonation tests in DI water using dimethylamine (DMA) as model precursor, the NDMA yield significantly increased in the presence of ammonia and bromide due to the formation of hydroxylamine and brominated nitrogenous oxidants. In addition, NDMA formation during ozonation of dimethylformamide (DMF), the other model precursor used in this study, occurred only in the presence of ammonia, and it was attributable to the oxidation of DMF by hydroxyl radicals. Filtered wastewater samples (0.7 μm) produced more NDMA than unfiltered samples, suggesting that ozone reacted with dissolved precursors and supporting the hypothesis of polymer degradation. Particularly, the total suspended solids content similarly affected NDMA formation and the UV absorbance decrease during ozonation due to the different ozone demand created in filtered and unfiltered samples.

Effects of molecular ozone and hydroxyl radical on formation of N-nitrosamines and perfluoroalkyl acids during ozonation of treated wastewaters

“…5,6 Human epidemiological studies have suggested some adverse health impacts resulting from exposure of PFAAs, including reports from the C8 Science Panel that link perfluorooctanoic acid (PFOA) to testicular and kidney cancer, as well as demonstrating an association between exposure to particular PFAAs (PFOA, perfluorooctane sulfonic acid (PFOS), and perfluorononanoic acid (PFNA)) and thyroid disease in children. [10][11][12][13][14][15] Nitrosamine formation during ozonation is generally limited to NDMA at relatively low concentrations (<25 ng L −1 ), but there are water matrices in which NDMA formation can exceed 100 ng L −1 . 9 A majority of nitrosamine research has focused on its formation from chloramination.…”

“…7,8 The health impacts and the persistence of these chemicals led the 2010/2015 PFOA Stewardship Program to call for phasing out PFOA by 2015. 14,15 There is a lack of information of PFAA formation during the ozonation of wastewaters. However, formation with ozone has also been shown in full-scale and pilot-scale wastewater treatment.…”

Toxicity of extracts from municipal wastewater to early life stages of Japanese medaka (Oryzias latipes) to evaluate removals of micropollutants by wastewater treatment

“…Treatment of wastewater by ozonation can result in the formation of transformation products that are more toxic than the original parent compounds (Lee and von Gunten ). Multiple studies have reported the formation of toxic transformation products after wastewater treatment by ozonation, including the formation of aldehydes, carboxylic acids, brominated organic compounds, and N‐nitrosodimethylamine (Huang et al ; Sgroi et al ; Gerrity et al ). Cao et al () observed significant disruptions in the hatching of Japanese medaka embryos exposed to ozonated wastewater.…”

Determination of a N-Nitrosodimethylamine Precursor in Water Using Ultra-high Performance Liquid Chromatography–Tandem Mass Spectrometry

“…[6][7][8][9] Compared to NDMA formation upon chloramination, reports of NDMA formation upon ozonation from water at water purification plants (WPPs) and sewage treatment plants (STPs) have been limited. [10][11][12][13] In the case of WPPs in Germany, N,N-dimethylsulfamide (DMS) was shown to be an NDMA precursor upon ozonation. 10 In the case of the Yodo River basin, Japan, the effluent from one STP (STP A) was the main source of NDMA precursors upon ozonation, and 1,1,5,5-tetramethylcarbohydrazide (TMCH) was the main NDMA precursor.…”