Ozone treatment of textile effluents and dyes: effect of applied ozone dose, pH and dye concentration

Abstract

The ozonation of wastewater supplied from a treatment plant (Samples A and B) and dyebath ef¯uent (Sample C) from a dyeing and ®nishing mill and acid dye solutions in a semi-batch reactor has been examined to explore the impact of ozone dose, pH, and initial dye concentration. Results revealed that the apparent rate constants were raised with increases in applied ozone dose and pH, and decreases in initial dye concentration. While the color removal ef®ciencies of both wastewater Samples A and C for 15 min ozonation at high ozone dosage were 95 and 97%, respectively, these were 81 and 87%, respectively at low ozone dosage. The chemical oxygen demand (COD) and dissolved organic carbon (DOC) removal ef®ciencies at several ozone dose applications for a 15 min ozonation time were in the ranges of 15±46% and 10±20%, respectively for Sample A and 15±33% and 9±19% respectively for Sample C. Ozone consumption per unit color, COD and DOC removal at any time was found to be almost the same while the applied ozone dose was different. Ozonation could improve the BOD 5 (biological oxygen demand) COD ratio of Sample A by 1.6 times with 300 mg dm À3 ozone consumption. Ozonation of acid dyes was a pseudo-®rst order reaction with respect to dye. Increases in dye concentration increased speci®c ozone consumption. Speci®c ozone consumption for Acid Red 183 (AR-183) dye solution with a concentration of 50 mg dm À3 rose from 0.32 to 0.72 mg-O 3 per mg dye decomposed as the dye concentration was increased to 500 mg dm À3.

Degradation of Red Anthraquinone Dyes: Alizarin, Alizarin S and Alizarin Complexone by Ozonation

“…In this paper we present results obtained with an advanced oxidation process for organic dyes in water effluents: ozonation, and we have selected three derivatives of antraquinone colorants because they are highly refractory to treatment procedures. Previous experiments [7]- [9], have shown ozone is able of removing dyes from water effluents, however, many times the organic content is only reduced but not eliminated.…”

Decolorisation of Textile Dyeing Effluents Using Advanced Oxidation Processes

“…As a result, it is hard to explain the overall degradation of the organic matter by ozone in textile wastewater individually. Thus, some global textile wastewater parameters such as color, COD and dissolved organic carbon are used for the degradation kinetic of organic matter by ozonation (Sevimli & Sarikaya, 2002, Selcuk, 2005. Textile wastewaters exhibit low BOD to COD ratios (< 0.1) indicating non-biodegradable nature of dyes and Wilmott et al(1998) have claimed that aerobic biological degradation is not always effective for textile dye contaminated effluent (Sevimli & Sarikaya, 2002).…”

“…Thus, some global textile wastewater parameters such as color, COD and dissolved organic carbon are used for the degradation kinetic of organic matter by ozonation (Sevimli & Sarikaya, 2002, Selcuk, 2005. Textile wastewaters exhibit low BOD to COD ratios (< 0.1) indicating non-biodegradable nature of dyes and Wilmott et al(1998) have claimed that aerobic biological degradation is not always effective for textile dye contaminated effluent (Sevimli & Sarikaya, 2002). Somensia et al, (2010) , tested pilot scale ozonation for the pre-treatment and colour removal of real textile effluent.…”

Decolorisation of exhausted reactive dye bath using ozonator for reuse

“…As a result, textile wet processing plants produce highly polluting wastewater (Ademorotti, 1992;Navarro, 2001;Wang, 2002;Sheng and Chi, 1993). Textile dyeing effluents are intensely colored and known to present extreme variations of pH and temperature, high COD and Dissolved Solids (Sevinmli and Kinaci, 2002;Sheng and Chen, 1997;Sevimli and Sarikaya, 2002). Strong color of the textile wastewater is the most serious problem of the textile waste effluent.…”