1. Formation of transformation products during ozonation of secondary wastewater effluent and their fate in post-treatment: From laboratory- to full-scale
- Author
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Baptiste Clerc, Christa S. McArdell, Urs von Gunten, Moreno Rutsch, Rebekka Gulde, and Jennifer E. Schollée
- Subjects
aqueous-solution ,Powdered activated carbon treatment ,Environmental Engineering ,drinking-water ,0208 environmental biotechnology ,Sand filter ,Powdered activated carbon ,02 engineering and technology ,010501 environmental sciences ,Wastewater ,01 natural sciences ,Ozone ,Granular activated carbon ,Micropollutants ,Structure elucidation ,law.invention ,Water Purification ,micropollutant elimination ,law ,Tandem Mass Spectrometry ,medicine ,activated carbon ,Waste Management and Disposal ,Effluent ,Filtration ,oxidation-products ,degradation ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Chemistry ,removal ,Ecological Modeling ,Pulp and paper industry ,Pollution ,020801 environmental engineering ,Filter (aquarium) ,kinetics ,Sewage treatment ,organic contaminants ,Laboratories ,Water Pollutants, Chemical ,Activated carbon ,medicine.drug - Abstract
Ozonation is increasingly applied in water and wastewater treatment for the abatement of micropollutants (MPs). However, the transformation products formed during ozonation (OTPs) and their fate in biological or sorptive post-treatments is largely unknown. In this project, a high-throughput approach, combining laboratory ozonation experiments and detection by liquid chromatography high-resolution mass spectrometry (LC-HR-MS/MS), was developed and applied to identify OTPs formed during ozonation of wastewater effluent for a large number of relevant MPs (total 87). For the laboratory ozonation experiments, a simplified experimental solution, consisting of surrogate organic matter (methanol and acetate), was created, which produced ozonation conditions similar to realistic conditions in terms of ozone and hydroxyl radical exposures. The 87 selected parent MPs were divided into 19 mixtures, which enabled the identification of OTPs with an optimized number of experiments. The following two approaches were considered to identify OTPs. (1) A screening of LC-HR-MS signal formation in these experiments was performed and revealed a list of 1749 potential OTP candidate signals associated to 70 parent MPs. This list can be used in future suspect screening studies. (2) A screening was performed for signals that were formed in both batch experiments and in samples of wastewater treatment plants (WWTPs). This second approach was ultimately more time-efficient and was applied to four different WWTPs with ozonation (specific ozone doses in the range 0.23-0.55 gO3/gDOC), leading to the identification of 84 relevant OTPs of 40 parent MPs in wastewater effluent. Chemical structures could be proposed for 83 OTPs through the interpretation of MS/MS spectra and expert knowledge in ozone chemistry. Forty-eight OTPs (58%) have not been reported previously. The fate of the verified OTPs was studied in different post-treatment steps. During sand filtration, 87-89% of the OTPs were stable. In granular activated carbon (GAC) filters, OTPs were abated with decreasing efficiency with increasing run times of the filters. For example, in a GAC filter with 16,000 bed volumes, 53% of the OTPs were abated, while in a GAC filter with 35,000 bed volumes, 40% of the OTPs were abated. The highest abatement (87% of OTPs) was observed when 13 mg/L powdered activated carbon (PAC) was dosed onto a sand filter., Water Research, 200, ISSN:0043-1354, ISSN:1879-2448
- Published
- 2021