Effect of some operational parameters on textile dye biodegradation in a sequential batch reactor

Area of Science:

• Environmental Biotechnology
• Wastewater Treatment
• Color Removal Technologies

Background:

• Textile industry effluents contain persistent dyes like Remazol Brilliant Violet 5R and Remazol Black B.
• Biological treatment using Sequencing Batch Reactors (SBRs) offers a sustainable approach for dye decolorization.

Purpose of the Study:

• To investigate the biological color removal efficiency of SBRs for simulated textile effluents containing specific azo dyes.
• To evaluate the impact of operational parameters like Sludge Retention Time (SRT) and aerated phase duration on dye removal.

Main Methods:

• Simulated textile wastewater containing Remazol Brilliant Violet 5R and Remazol Black B was treated in an SBR.
• Experiments involved varying SRT (15 and 20 days) and aerated reaction phase duration (10 and 12 hours).
• Abiotic tests were conducted using sterilized SBR samples to differentiate biological and non-biological removal mechanisms.

Main Results:

• 90% color removal for violet dye was achieved with a 24-h cycle, 15-day SRT, and 10-h aeration.
• 75% color removal for black dye was observed under identical conditions, with no improvement at 20-day SRT.
• Increasing aeration to 12 hours reduced violet dye removal to 75% and did not enhance aromatic amine biodegradation.

Conclusions:

• SBRs demonstrate significant potential for decolorizing textile wastewater, particularly for violet azo dyes.
• The efficiency of color removal is dye-specific and influenced by operational parameters.
• Non-biological factors, possibly involving reducing substances in SBR biomass, contribute to color removal.