Removal of COD and color from hydrolyzed textile azo dye by combined ozonation and biological treatment

The application of ozonation has been increasing in recent years, the main disadvantage of this type of treatment being related to the by-products, which can have toxic and carcinogenic properties, and therefore should be studied further. In this study, the combined treatment of ozonation and subseq...

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Bibliographic Details
Published in:	Journal of hazardous materials Vol. 179; no. 1; pp. 35 - 42
Main Authors:	de Souza, Selene Maria de Arruda Guelli Ulson, Bonilla, Karin Angela Santos, de Souza, Antônio Augusto Ulson
Format:	Journal Article
Language:	English
Published:	Kidlington Elsevier B.V 15-07-2010 Elsevier
Subjects:	Animals Applied sciences Azo Compounds - isolation & purification Bacteria - chemistry Bacteria - metabolism Biodegradation, Environmental Biofilm Biofilms Biological Byproducts Calibration Color Coloring Agents - isolation & purification Crack opening displacement Daphnia Daphnia magna Degradation Dye Dyes Effluents Exact sciences and technology General purification processes General treatment and storage processes Hydrogen-Ion Concentration Kinetics Microscopy, Electron, Scanning Naphthalenesulfonates Oxidants, Photochemical - chemistry Oxygen - chemistry Ozonation Ozone - chemistry Pollution Spectrophotometry, Ultraviolet Textile effluent Textile Industry Toxicity Waste water Wastes Wastewaters Water treatment and pollution Ozonation Biofilm Dye Textile effluent Toxicity Discoloration Waste treatment Waste water Ozonization Chemical oxygen demand Azo dye pH Biological treatment Textile industry Biodegradation Pollutant behavior Reaction product Color Ozone Industrial waste water First order Water quality Physicochemical purification Combined treatment Kinetics
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Summary:	The application of ozonation has been increasing in recent years, the main disadvantage of this type of treatment being related to the by-products, which can have toxic and carcinogenic properties, and therefore should be studied further. In this study, the combined treatment of ozonation and subsequent biological degradation with a biofilm, to reduce the color and chemical oxygen demand (COD), was investigated. The experimental part of the study consisted of two phases. The first phase was the ozonation process, the results obtained demonstrated that the ozonation of Remazol Black B dye at pH values of 3–11, was effective, partially oxidizing and completely decolorizing the effluent, even at relatively high concentrations of the dye (500 mg/L). Color removal efficiencies greater than 96% were obtained in all cases. The degradation kinetics of ozone is a pseudo-first-order reaction with respect to the dye concentration. It was possible to verify that the ozonation process as a pre-treatment increases the dye degradation efficiency. For the biological treatment, an increase in ozonization time increased the dye concentration reduction in hydrolyzed dye synthetic effluent. The toxicological results of the tests with Daphnia Magna showed that there is an increase in toxicity after ozonization and a decrease after submitting the ozonized synthetic wastewater to biological treatment with a biofilm.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0304-3894 1873-3336
DOI:	10.1016/j.jhazmat.2010.02.053