Dissolved organic matter processing and photoreactivity in a wastewater treatment constructed wetland

Sardana, A. K.; Cottrell, Barbara A.; Soulsby, David; Aziz, Tarek N.

doi:10.1016/j.scitotenv.2018.08.138

Cited by 38 publications

(34 citation statements)

References 95 publications

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“…E 2 / E 3 ratios (Figure S4b), which inversely correlate with DOM molecular size, , indicate increasing molecular size in the vegetated wetlands and a decrease in the open water wetland. Comparison to spectroscopic data of SRFA and PLFA, recognized as fulvic acid end-members of terrestrially/higher-plant derived (allochthonous) and aquatic/microbial derived (autochthonous) aquatic DOM, , respectively, suggests that DOM in the vegetated cells became more terrestrial-like, which is in agreement with previous studies, ,,− while DOM became more aquatic-like in the open-water cell. A similar trend was also observed for the isolated wetland DOMs, indicating that alterations of DOM occurring in the wetlands were reflected in the isolates (Figure S3).…”

Section: Resultssupporting

confidence: 91%

“…Others have observed an increase in PPRI formation of DOM after passage through wetland systems and ascribed this to the contribution of terrestrial-type DOM released into the wetland by decaying plant material. 45,81 Here, the decrease in quantum yields for the vegetated wetland cells can be at least partly attributed to the release of light-absorbing DOM not serving as reactive species precursor. Additionally, the plant derived DOM could act as triplet state quencher and thereby decrease quantum yields.…”

Section: Environmental Science and Technologymentioning

confidence: 93%

“…Finally, the ability of wetland and standard DOMs to associate with the bacterial cells was evaluated. Recent work has investigated both the composition and the photochemistry of DOM in a constructed treatment wetland using comparable spectroscopic and photochemical diagnostic tools as applied in this study . However, to our knowledge this is the first comprehensive investigation of changes in spectroscopic, photochemical, and photoinactivating properties of DOM during passage through a wetland system, including a comparison of DOM extracts with the original water samples.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Natural Photosensitizers in Constructed Unit Process Wetlands: Photochemical Characterization and Inactivation of Pathogen Indicator Organisms

Wenk

Nguyen

Nelson

2019

Environ. Sci. Technol.

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Dissolved organic matter (DOM) is a natural photosensitizer that contributes to the inactivation of microbial pathogens. In constructed treatment wetlands with open water areas DOM can promote sunlight disinfection of wastewater effluent, but a better understanding of DOM spectroscopic and photochemical properties and how they are impacted by different unit process wetlands is needed to inform design. The goals of this study were: (1) to investigate whether DOM isolates realistically represent the photochemistry of the source DOM in its original water and (2) to observe how changes of DOM along a treatment wetland affect its photochemistry, including pathogen inactivation. A pilot scale unit process wetland was studied that consisted of three different cells (open water, cattail, and bulrush) fed by secondary wastewater effluent. DOM was isolated using solid-phase extraction (SPE), photochemically characterized, and compared to the original water samples and standard DOMs. For MS2 coliphage, a virus indicator, the most efficient photosensitizer was the wastewater DOM isolated from the influent of the wetland, while for the bacterial indicator Enterococcus faecalis, inactivation results were comparable across wetland isolates. SPE resulted in isolation of 47% to 59% of whole water DOM and enriched for colored DOM. Singlet oxygen precursors were efficiently isolated, while some excited triplet state precursors remained in the extraction discharge. DOM processing indicators such as SUVA254, SUVA280, and spectral slopes including E 2/E 3 ratios were reflected in the isolates. Photoinactivation of MS2 was significantly lower in both the reconstituted water samples and isolates compared to the original water sample, possibly due to disturbance of the trans-molecular integrity of DOM molecules by SPE that affects distance between MS2 and DOM sites with locally higher singlet oxygen production. For E. faecalis, results were similar in original water samples and isolates. Higher sorption of DOM to E. faecalis was roughly correlated with higher photoinactivation rates. To enhance sunlight disinfection in unit process wetlands, there is no advantage to placing open water cells after vegetated cells, as passage through the vegetated cells led to increased light absorption and lower singlet oxygen and triplet-state quantum yields and steady state concentrations.

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Section: Resultssupporting

confidence: 91%

Section: Environmental Science and Technologymentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Natural Photosensitizers in Constructed Unit Process Wetlands: Photochemical Characterization and Inactivation of Pathogen Indicator Organisms

Wenk

Nguyen

Nelson

2019

Environ. Sci. Technol.

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“…Extended aeration (longer SRT) or aeration with pure oxygen or membrane systems could lead to better removal and degradation of the QACs. Treatment wetlands, which facilitate extended biodegradation, photolysis, and removal via particle settling would likely lead to QAC removal. − Pyrolysis of biosolids to generate biochar would very likely lead to QAC removal from biosolids. , Various advanced oxidation processes, including O 3 /H 2 O 2 , UV/chlorine, and O 3 /HOCl, have been shown to degrade QACs and eliminate the toxicity to bacteria or algae. − …”

Section: Implications and Interventionsmentioning

confidence: 99%

Increased Use of Quaternary Ammonium Compounds during the SARS-CoV-2 Pandemic and Beyond: Consideration of Environmental Implications

Hora

Pati

McNamara

et al. 2020

Environ. Sci. Technol. Lett.

272

288

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Quaternary ammonium compounds (QACs) are active ingredients in over 200 disinfectants currently recommended by the U.S. EPA for use to inactivate the SARS-CoV-2 (COVID-19) virus. The amounts of these compounds used in household, workplace, and industry settings has very likely increased, and usage will continue to be elevated given the scope of the pandemic. QACs have been previously detected in wastewater, surface waters, and sediments, and effects on antibiotic resistance have been explored. Thus, it is important to assess potential environmental and engineering impacts of elevated QAC usage, which may include disruption of wastewater treatment unit operations, proliferation of antibiotic resistance, formation of nitrosamine disinfection byproducts, and impacts on biota in surface waters. The threat caused by COVID-19 is clear, and a reasonable response is elevated use of QACs to mitigate spread of infection. Exploration of potential effects, environmental fate, and technologies to minimize environmental releases of QACs, however, is warranted.

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“…The removal of EPs by CWs is mainly through the absorption and degradation (Li, Gao, et al, 2019; Li, Li, et al, 2019; Li, Zhang, Zeng, et al, 2019; Li, Liu, Zhang, Li, et al, 2019; Li, Zhang, Xia, Wang, et al, 2019; Li, Zhang, Hu, et al, 2019; Li, Sun, Zhang, Feng, et al, 2019; Li, Wang, et al, 2019; Li, Yuan, Gao, et al, 2019; Rabello et al, 2019). Adsorption is an important way to remove EPs, and the substrate, soil, and sediment of packed bed in CWs play major roles in adsorption (Nguyen, Chao, & Chen, 2019; Nguyen, Afzal, et al, 2019; Sardana, Cottrell, Soulsby, & Aziz, 2019; Zhao, Yan, et al, 2019; Zhao, Jian, et al, 2019). The degradation of EPs in CWs is mainly through microbial degradation, photolysis, and hydrolysis (Tara et al, 2019).…”

Section: Engineered Wetlands and Natural Systemsmentioning

confidence: 99%

Emerging pollutants—Part II: Treatment

Liu

Zhang

Chang

2020

Water Environment Research

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Emerging pollutants (EPs) refer to a class of pollutants, which are emerging in the environment or recently attracted attention. EPs mainly include pharmaceutical and personal care products (PPCPs), endocrine-disrupting chemicals (EDCs), and antibiotic resistance genes (ARGs). EPs have potential threats to human health and ecological environment. In recent years, the continuous detections of EPs in surface and ground water have brought huge challenges to water treatment and also made the treatment of EPs become an international research hotspot. This paper summarizes some research results on EPs treatment published in 2019. This paper may be helpful to understand the current situations and development trends of EP treatment technologies.

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Dissolved organic matter processing and photoreactivity in a wastewater treatment constructed wetland

Cited by 38 publications

References 95 publications

Natural Photosensitizers in Constructed Unit Process Wetlands: Photochemical Characterization and Inactivation of Pathogen Indicator Organisms

Natural Photosensitizers in Constructed Unit Process Wetlands: Photochemical Characterization and Inactivation of Pathogen Indicator Organisms

Increased Use of Quaternary Ammonium Compounds during the SARS-CoV-2 Pandemic and Beyond: Consideration of Environmental Implications

Emerging pollutants—Part II: Treatment

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