Ozonation of lake water and wastewater: Identification of carbonous and nitrogenous carbonyl-containing oxidation byproducts by non-target screening

• Published in: Water research (Oxford) Vol. 232; p. 119484
• Main Authors: Houska, Joanna, Manasfi, Tarek, Gebhardt, Isabelle, von Gunten, Urs
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.04.2023
• Subjects: Acrolein - analysis; Aldehydes; Carbon - analysis; Carbonyl compounds; Dissolved organic matter; Drinking Water - analysis; High resolution mass spectrometry; Ketones - analysis; Lake water; Lakes - analysis; Nitrogen - analysis; Ozonation; Ozone - chemistry; Phenols; Wastewater; Water Pollutants, Chemical - chemistry; Water Purification - methods; Carbonyl compounds; Lake water; Dissolved organic matter; High resolution mass spectrometry; Ozonation; Phenols; Wastewater
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2022.119484

•Ozonation of lake water and wastewater: detection of 178 carbonyl compounds.•15 carbonous and nitrogenous carbonyl compounds structurally elucidated.••OH scavenger and pH have a minor influence on the subset of carbonyl compounds detected in all water types.•30% N-containing carbonyl compounds in ozonated wastewater vs. 17% in lake water. Ozonation of drinking water and wastewater is accompanied by the formation of disinfection byproducts (DBPs) such as low molecular weight aldehydes and ketones from the reactions of ozone with dissolved organic matter (DOM). By applying a recently developed non-target workflow, 178 carbonous and nitrogenous carbonyl compounds were detected during bench-scale ozonation of two lake waters and three secondary wastewater effluent samples and full-scale ozonation of secondary treated wastewater effluent. An overlapping subset of carbonyl compounds (20%) was detected in all water types. Moreover, wastewater effluents showed a significantly higher fraction of N-containing carbonyl compounds (30%) compared to lake water (17%). All carbonyl compounds can be classified in 5 main formation trends as a function of increasing specific ozone doses. Formation trends upon ozonation and comparison of results in presence and absence of the •OH radical scavenger DMSO in combination with kinetic and mechanistic information allowed to elucidate potential carbonyl structures. A link between the detected carbonyl compounds and their precursors was established by ozonating six model compounds (phenol, 4-ethylphenol, 4-methoxyphenol, sorbic acid, 3-buten-2-ol and acetylacetone). About one third of the detected carbonous carbonyl compounds detected in real waters was also detected by ozonating model compounds. Evaluation of the non-target analysis data revealed the identity of 15 carbonyl compounds, including hydroxylated aldehydes and ketones (e.g. hydroxyacetone, confidence level (CL) = 1), unsaturated dicarbonyls (e.g. acrolein, CL = 1; 2-butene-1,4-dial, CL = 1; 4-oxobut-2-enoic acid, CL = 2) and also a nitrogen-containing carbonyl compound (2-oxo-propanamide, CL =1). Overall, this study shows the formation of versatile carbonous and nitrogenous carbonyl compounds upon ozonation involving ozone and •OH reactions. Carbonyl compounds with unknown toxicity might be formed, and it could be demonstrated that acrolein, malondialdehyde, methyl glyoxal, 2-butene-1,4-dial and 4-oxo-pentenal are degraded during biological post-treatment. [Display omitted]