title: Treatment of waste metalworking fluid by a hybrid ozone-biological process.
abstract: In metal machining processes, the regulation of heat generation and lubrication at the contact point are achieved by application of a fluid referred to as metalworking fluid (MWF). MWFs inevitably become operationally exhausted with age and intensive use, which leads to compromised properties, thereby necessitating their safe disposal. Disposal of this waste through a biological route is an increasingly attractive option, since it is effective with relatively low energy demands. However, successful biological treatment is challenging since MWFs are chemically complex, and include biocides specifically to retard microbial deterioration whilst the fluids are operational. In this study remediation of the recalcitrant component of a semi-synthetic MWF by a novel hybrid ozone-bacteriological treatment, was investigated. The hybrid treatment proved to be effective and reduced the chemical oxygen demand by 72% (26.9% and 44.9% reduction after ozonation and biological oxidation respectively). Furthermore, a near-complete degradation of three non-biodegradable compounds (viz. benzotriazole, monoethanolamine, triethanolamine), commonly added as biocides and corrosion inhibitors in MWF formulations, under ozonation was observed.
authors.affiliation: Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK.
authors.forename: Sheeja
authors.initials: S
authors.lastname: Jagadevan
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Graham
authors.forename: Ian P
authors.initials: IP
authors.lastname: Thompson
mesh_terms: D001419:Bacteria / Q000378:metabolism; D057919:Biological Oxygen Demand Analysis; D004202:Disinfectants / Q000737:chemistry* / Q000378:metabolism; D019856:Ethanolamine / Q000737:chemistry / Q000378:metabolism; D004983:Ethanolamines / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D008669:Metallurgy; D016877:Oxidants / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry*; D014230:Triazoles / Q000737:chemistry / Q000378:metabolism; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000378:metabolism
chemical_list: D004202:Disinfectants; D019856:Ethanolamine; D004983:Ethanolamines; D007220:Industrial Waste; D016877:Oxidants; D010126:Ozone; D014230:Triazoles; D062065:Wastewater; D014874:Water Pollutants, Chemical; C012771:benzotriazole; C009546:triethanolamine