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Justo A.,University of Barcelona | Gonzalez O.,University of Barcelona | Acena J.,CSIC - Institute of Environmental Assessment And Water Research | Mita L.,CSIC - Institute of Environmental Assessment And Water Research | And 8 more authors.
Journal of Chemical Technology and Biotechnology | Year: 2014

BACKGROUND: The persistence of microcontaminants through conventional wastewater treatments is a matter of concern and it suggests the implementation of advanced treatment steps. Although there is evidence that reverse osmosis (RO) is the most efficient treatment for the the removal of these compounds, it has the drawback of producing significant amounts of highly polluted brine. In this work, chemical analyses and toxicity bioassays were combined to evaluate the removal of different pharmaceuticals and of dioxin-like compounds from RO brine through oxidative processes such as ozone, UV and UV/H2O2. RESULTS: The removal of the selected pharmaceuticals required a relatively high oxidative capacity, either by ozonation or by the combination of UV radiation and H2O2. Bioassays showed a significant dioxin-like activity in brine samples, whereas antibacterial or estrogenic activities were negligible. UV by itself was the least efficient in removing this dioxin-like activity. Ozonation appeared as the most competent treatment. CONCLUSIONS: The results of this work indicate the usefulness of advanced oxidation methods, especially ozonation, to remove biologically active micropollutants from brine samples. They also show that only the combination of chemical analyses and bioassays allows complete characterization of the efficiency of advanced water treatment processes to remove recalcitrant pollutants. © 2014 Society of Chemical Industry.

Olmez-Hanci T.,Technical University of Istanbul | Dursun D.,Technical University of Istanbul | Aydin E.,Technical University of Istanbul | Arslan-Alaton I.,Technical University of Istanbul | And 7 more authors.
Chemosphere | Year: 2015

The performance of S2O82-/UV-C and H2O2/UV-C treatments was investigated for the degradation and detoxification of Bisphenol A (BPA). The acute toxicity of BPA and its degradation products was examined with the Vibrio fischeri bioassay, whereas changes in estrogenic activity were followed with the Yeast Estrogen Screen (YES) assay. LC and LC-MS/MS analyses were conducted to determine degradation products evolving during photochemical treatment. In addition, BPA-spiked real freshwater samples were also subjected to S2O82-/UV-C and H2O2/UV-C treatment to study the effect of a real water matrix on BPA removal and detoxification rates. BPA removal in pure water was very fast (≤7min) and complete via both H2O2/UV-C and S2O82-/UV-C treatment, accompanied with rapid and significant mineralization rates ranging between 70% and 85%. V. fischeri bioassay results indicated that degradation products being more toxic than BPA were formed at the initial stages of H2O2/UV-C whereas a rapid and steady reduction in toxicity was observed during S2O82-/UV-C treatment in pure water. UV-C treatment products exhibited a higher estrogenic activity than the original BPA solution while the estrogenicity of BPA was completely removed during H2O2/UV-C and S2O82-/UV-C treatments parallel to its degradation. 3-methylbenzoic and 4-sulfobenzoic acids, as well as the ring opening products fumaric, succinic and oxalic acids could be identified as degradation products. BPA degradation required extended treatment periods (20min) and TOC removals were considerably retarded (by 40%) in the raw freshwater matrix most probably due to its natural organic matter content (TOC=5.1mgL-1). H2O2/UV-C and S2O82-/UV-C treatment in raw freshwater did not result in toxic degradation products. © 2014 Elsevier Ltd.

Olmez-Hanci T.,Technical University of Istanbul | Arslan-Alaton I.,Technical University of Istanbul | Dursun D.,Technical University of Istanbul | Genc B.,Technical University of Istanbul | And 5 more authors.
Photochemical and Photobiological Sciences | Year: 2015

The degradation and mineralization of the nonionic surfactant octylphenol ethoxylate (OPEO), commercially known as Triton™ X-45, by the peroxymonosulfate (PMS)/UV-C process were investigated. Three different toxicity tests (Daphnia magna, Vibrio fischeri and Pseudokirchneriella subcapitata) as well as the Yeast Estrogen Screen (YES) bioassay were undertaken to evaluate the potential toxic and estrogenic effects of OPEO and its oxidation products. OPEO removal was very fast and complete after 7 min via PMS/UV-C treatment under the investigated reaction conditions (OPEO = 20 mg L-1 (47 μM); TOC = 12 mg L-1; PMS = 2.5 mM; initial reaction pH = 6.5; applied UV-C dose = 21 Wh L-1). TOC removal also proceeded rapidly; a gradual decrease was observed resulting in an overall TOC removal of 84%. The toxic responses of PMS/UV-C treated OPEO solutions varied according to the test organism used in the bioassay. Daphnia magna was found to be most sensitive to aqueous OPEO, whereas Pseudokirchneriella subcapitata appeared to be the least sensitive one. Daphnia magna and Vibrio fischeri tests revealed that the inhibitory effect of OPEO decreased significantly during the course of treatment. On the other hand, PMS/UV-C oxidation products exhibited a high toxic effect towards Pseudokirchneriella subcapitata (around 60%). YES test results underlined the need for improving the PMS/UV-C treatment performance to remove the estrogenic activity of OPEO and its oxidation products. This journal is © The Royal Society of Chemistry and Owner Societies 2015.

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