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Ozone Treatment of Tannery Wastewater Monitored by Conventional and Substance Specific Wastewater Analyses

ABSTRACT Ozone is an unstable and highly reactive gas applied in drinking water or wastewater treatment to oxidize and/or mineralize pollutants. Its application in wastewater treatment leads to a destruction of persistent pollutants combined with an improvement of biodegradability. The oxidation of organic and inorganic compounds in tannery wastewater at different pHs applying O3 was studied. Results after O3-treatment were determined by conventional wastewater parameters, e.g., total organic carbon (TOC), biochemical oxygen demand after 5 days (BOD5), and chemical oxygen demand (COD), as well as by substance-specific mass spectrometric analytical techniques, i.e., gas chromatography—mass spectrometry (GC/MS) and liquid chromatography—mass and tandem mass spectrometry (LC/MS and—MSn). In parallel, variations in the toxicity of the tannery wastewater against water organisms before and after O3-treatment were determined by means of biotoxicity testing, i.e., Daphnia magna Straus and Vibrio fischeri bioassays.