Catalytic ozonation of textile wastewater as a polishing step after industrial scale electrocoagulation
| Autor: | Stanisław Ledakowicz, Magdalena Foszpańczyk, Kazimierz Blus, Marta Gmurek, Lucyna Bilińska |
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| Rok vydání: | 2019 |
| Předmět: |
Environmental Engineering
medicine.medical_treatment 0208 environmental biotechnology Alkalinity Industrial Waste 02 engineering and technology 010501 environmental sciences Management Monitoring Policy and Law Wastewater 01 natural sciences Waste Disposal Fluid Electrocoagulation Catalysis Industrial wastewater treatment Ozone medicine Coloring Agents Waste Management and Disposal 0105 earth and related environmental sciences Chemistry Textiles Chemical oxygen demand General Medicine Pulp and paper industry 020801 environmental engineering Textile Industry Dyeing Water Pollutants Chemical Activated carbon medicine.drug |
| Zdroj: | Journal of environmental management. 265 |
| ISSN: | 1095-8630 |
| Popis: | The main objective of this study was to develop the treatment system to change wastewater into a reliable source of recyclable water within the textile plant. Therefore, a highly polluted industrial wastewater originated in the dyeing of cotton was subjected to a multi-step treatment. The raw wastewater was characterized by the concentration of Reactive Black 5, the azo dye, as high as 842 mg/L, extreme alkalinity (pH 11.26) and salinity (NaCl concentration 52,290 mg/L). Correspondingly, the chemical oxygen demand (COD) was equal to 3440 mg/L and the total organic carbon (TOC) was 1790 mg/L in this wastewater. This salty, hardly degradable wastewater underwent the electrocoagulation (EC) on an industrial scale in the first step of the treatment. Although the industrial EC resulted in 84% of color removal in a very short time of 8 min, the wastewater was still characterized by an extremally high absorbance which corresponded to 100 mg/L of RB5. Moreover, EC resulted in the occurrence of burdensome by-products, of which one was identified in this study as an aniline derivative. The by-products contributed to high residual COD and TOC after EC (2120 mg/L and 1052 mg/L, respectively). Consequently, the catalytic ozonation was used by us as a second, the polishing, step of the treatment. The catalytic ozonation was found efficient in the removal of the residual color and colorless by-products. The wastewater after catalytic ozonation was colorless and the final COD and TOC decreased to 1283 and 695 mg/L, respectively. The average oxidation state (AOS), spectra analysis, and the toxicity assay showed catalytic ozonation efficient in the by-products oxidation. Consequently, the catalytic action of activated carbon (AC) was proved for the ozonation of textile wastewater. Ultimately, the recycling of purified wastewater into dyeing resulted in a very good color quality of textile samples (DECMC values below limiting value equal to 1.0). |
| Databáze: | OpenAIRE |
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