Non-target mass spectrometry analysis of NDMA precursors in advanced treatment for potable reuse

Roback, Shannon L.; Ferrer, Imma; Thurman, E. Michael; Ishida, Kenneth P.; Plumlee, Megan H.; Poustie, Andrew; Westerhoff, Paul; Hanigan, David

doi:10.1039/c8ew00401c

Cited by 16 publications

(22 citation statements)

References 40 publications

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“…NDMA is particularly challenging for facilities purifying municipal wastewater effluents for potable reuse. The full advanced treatment (FAT) train frequently employed at these facilities consists of microfiltration (MF) and reverse osmosis (RO) membranes as physical barriers to contaminants, followed by an UV-based advanced oxidation process (AOP) as a photochemical barrier. , NDMA concentrations in sewage or primary effluents can be ≥30 ng/L. , NDMA precursors are associated with wastewater effluents, − and the chloramines applied to control biofouling on MF and RO membranes react with these precursors to form NDMA upstream of RO treatment. − Because NDMA is only partially rejected by RO membranes, ,− the AOP employs up to 1000 mJ/cm 2 UV fluence to reduce the NDMA concentrations in RO permeates to <10 ng/L. ,, …”

Section: Introductionmentioning

confidence: 99%

N-Nitrosodimethylamine Formation during UV/Hydrogen Peroxide and UV/Chlorine Advanced Oxidation Process Treatment Following Reverse Osmosis for Potable Reuse

Szczuka

Huang

MacDonald

et al. 2020

Environ. Sci. Technol.

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Chloramines applied to control microfiltration and reverse osmosis (RO) membrane biofouling in potable reuse trains form the potent carcinogen, N-nitrosodimethylamine (NDMA). In addition to degrading other contaminants, UV-based advanced oxidation processes (AOPs) strive to degrade NDMA by direct photolysis. The UV/chlorine AOP is gaining attention because of its potential to degrade other contaminants at lower UV fluence than the UV/hydrogen peroxide AOP, although previous pilot studies have observed that the UV/chlorine AOP was less effective for NDMA control. Using dimethylamine (DMA) as a model precursor and secondary municipal wastewater effluent, this study evaluated NDMA formation during the AOP treatment via two pathways. First, NDMA formation by UV treatment of monochloramine (NH 2 Cl) and chlorinated DMA (Cl-DMA) passing through RO membranes was maximized at 350 mJ/cm 2 UV fluence, declining at higher fluence, where NDMA photolysis outweighed NDMA formation. Second, this study demonstrated that chlorine addition to the chloramine-containing RO permeate during the UV/ chlorine AOP treatment initiated rapid NDMA formation by dark breakpoint reactions associated with reactive intermediates from the hydrolysis of dichloramine. At pH 5.7, this formation was maximized at a chlorine/ammonia molar ratio of 3 (out of 0−10), conditions typical for UV/chlorine AOPs. At 700 mJ/cm 2 UV fluence, which is applicable to current practice, NDMA photolysis degraded a portion of the NDMA formed by breakpoint reactions. Lowering UV fluence to ∼350 mJ/cm 2 when switching to the UV/chlorine AOP exacerbates effluent NDMA concentrations because of concurrent NDMA formation via the UV/NH 2 Cl/Cl-DMA and breakpoint chlorination pathways. Fluence >700 mJ/cm 2 or chlorine doses greater than the 3:1 chlorine/ammonia molar ratios under consideration for the UV/HOCl AOP treatment are needed to achieve NDMA control.

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Section: Introductionmentioning

confidence: 99%

N-Nitrosodimethylamine Formation during UV/Hydrogen Peroxide and UV/Chlorine Advanced Oxidation Process Treatment Following Reverse Osmosis for Potable Reuse

Szczuka

Huang

MacDonald

et al. 2020

Environ. Sci. Technol.

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“…Pharmaceuticals have received global attention because of their persistence in aquatic environments and deleterious effects on aquatic life (Brausch & Rand, 2011; Gogoi et al, 2018; Yang et al, 2017). Pharmaceuticals are poorly removed by conventional wastewater treatment plants (Roback et al, 2018; Sharma et al, 2020; Zupanc et al, 2013) resulting in their occurrence in groundwater, lakes, foodstuff, and even in drinking water at concentrations from low ng/L to µg/L (Boyd et al, 2003; Ebele et al, 2017; Gogoi et al, 2018; Kolpin et al, 2002; McEachran et al, 2016; Poustie et al, 2020; Sharma et al, 2020; Yang et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Quantification of pharmaceuticals in the sealant fluids of actively used waterless urinals

Thapa

Sharma

Hanigan

2021

Water Environment Research

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Prior measurements at bench scale revealed that waterless urinal cartridges containing oily sealant fluids are capable of partitioning pharmaceuticals from urine and therefore reducing their concentration in wastewater. We sought to measure pharmaceutical removal from in‐use waterless urinals. We developed a method to quantify pharmaceuticals in the sealant phase, which resulted in 79 ± 30% and 71 ± 30% recovery of eight pharmaceuticals from two sealant fluids, respectively. The method was applied to sealant samples collected over three weeks from in‐use waterless urinals on a university campus. Six of eight pharmaceuticals were present in the sealant samples from 1.4 µg/L to 241 µg/L. Loads of the six pharmaceuticals detected in the sealants were removed from the receiving wastewater from 0.02 µg/day to 3.4 µg/day across the sampling period. The concentration of the pharmaceuticals were similar over time, indicating rapid saturation and washout of the sealant. We also observed relatively rapid loss of sealant at maintenance intervals consistent with the manufacturer's instructions. These findings indicate that while waterless urinals do remove some pharmaceuticals from the wastewater stream, meaningful changes to wastewater concentrations will only result if the sealant fluid and/or the urinal cartridge are significantly modified. Practitioner points We developed a quantification method for pharmaceuticals in oily waterless urinal sealants. Pharmaceuticals were present at relatively low concentrations in the sealant phase of two in‐use waterless urinals. We identify engineering challenges that must be overcome to meaningfully reduce pharmaceutical loads in wastewater with waterless urinals.

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“…Although RO is highly effective at removing organic compounds (e.g., 99% removal of total organic carbon), Roback et al showed that NDMA precursors are not fully removed by RO, where typical removal was ∼90%. 17,19 During subsequent UV-AOP, if the remaining precursors are not sufficiently removed or if new precursors are formed, the NDMA concentration has the potential to rebound after UV-AOP in the finished water despite NDMA being reduced to nondetectable levels by the UV-AOP. 19,20 NDMA rebound can occur as a result of the post-treatment stabilization process because NDMA formation is favored at higher pH.…”

Section: Introductionmentioning

confidence: 99%

“…Studies indicate that wastewater is enriched with secondary and tertiary amines and that effluent organic matter (EfOM) from wastewater contains NDMA precursors. − However, the specific precursors responsible for the majority of NDMA formed in treated wastewaters are unknown. Several studies have isolated and identified specific precursors in wastewater, but on the basis of their low occurrence and typically low yields, ,,, the authors hypothesize that the precursors identified to date do not explain the levels of NDMA that form in treated wastewater. Hence, it is possible that a wide range of precursors, each occurring at low concentrations, are together responsible for the measured NDMA that forms.…”

Section: Introductionmentioning

confidence: 99%

“…NDMA is highly susceptible to photolysis by the UV-AOP process. , However, less is known about the susceptibility of NDMA precursors to UV-AOP. Although RO is highly effective at removing organic compounds (e.g., 99% removal of total organic carbon), Roback et al showed that NDMA precursors are not fully removed by RO, where typical removal was ∼90%. , During subsequent UV-AOP, if the remaining precursors are not sufficiently removed or if new precursors are formed, the NDMA concentration has the potential to rebound after UV-AOP in the finished water despite NDMA being reduced to nondetectable levels by the UV-AOP. , NDMA rebound can occur as a result of the post-treatment stabilization process because NDMA formation is favored at higher pH. ,, The pH of RO permeate is typically ∼5.5. Post-treatment stabilization is often employed by FAT facilities as a final step to decrease the corrosivity of the highly purified water by adding slaked lime [Ca(OH) 2 ] or NaOH to increase the pH .…”

Section: Introductionmentioning

confidence: 99%

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Pilot UV-AOP Comparison of UV/Hydrogen Peroxide, UV/Free Chlorine, and UV/Monochloramine for the Removal of N-Nitrosodimethylamine (NDMA) and NDMA Precursors

et al. 2020

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Three different ultraviolet-advanced oxidation processes (UV-AOPs) (UV/hydrogen peroxide, UV/free chlorine, and UV/supplemental monochloramine) used in full advanced treatment (FAT) for potable reuse were evaluated at pilot scale using reverse osmosis (RO) permeate from a FAT facility. Oxidant concentrations were varied, and each AOP was assessed for its ability to remove N-nitrosodimethylamine (NDMA) and NDMA precursors. For all AOPs, NDMA was removed well (to near 1.2 ng/L). However, UV/free chlorine exhibited less apparent NDMA destruction, and this level of destruction decreased as the free chlorine concentration increased. Removal of NDMA precursors was variable with no oxidant showing superior performance, ranging widely from 1% to 84% removal. The level of NDMA precursors increased in only two of 38 UV-AOP pilot tests, suggesting that formation of NDMA precursors by UV-AOP is limited. Adjustment of the UV-AOP pH was evaluated as a strategy for controlling NDMA precursors. Increasing the RO permeate pH prior to UV-AOP from 5.5 (ambient pH) to ∼7.0 using NaOH, to decrease the dichloramine concentration, decreased the level of destruction of NDMA precursors (i.e., increased the level of NDMA formation) in the UV/HOCl AOP (likely due to an increased level of radical scavenging by OCl–). Increasing the pH to ∼8.5 via the addition of lime decrease the level of NDMA destruction in the UV/H2O2 AOP due to the lower NDMA quantum yield at higher pH.

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Non-target mass spectrometry analysis of NDMA precursors in advanced treatment for potable reuse

Abstract: Non-target high-resolution mass spectrometry was used to track the occurrence and removal of NDMA precursors during advanced treatment for reuse.

Cited by 16 publications

References 40 publications

N-Nitrosodimethylamine Formation during UV/Hydrogen Peroxide and UV/Chlorine Advanced Oxidation Process Treatment Following Reverse Osmosis for Potable Reuse

N-Nitrosodimethylamine Formation during UV/Hydrogen Peroxide and UV/Chlorine Advanced Oxidation Process Treatment Following Reverse Osmosis for Potable Reuse

Quantification of pharmaceuticals in the sealant fluids of actively used waterless urinals

Pilot UV-AOP Comparison of UV/Hydrogen Peroxide, UV/Free Chlorine, and UV/Monochloramine for the Removal of N-Nitrosodimethylamine (NDMA) and NDMA Precursors

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