Integrated Treatment of textile wastewater and Methyl Orange Azo Dye: Constructed Wetland-based Remediation Enhanced by Bacterial Treatment

The textile industry significantly contributes to environmental pollution through the discharge of dye-laden wastewater. Among these dyes, methyl orange, an azo dye, is particularly challenging to remove due to its stability and potential toxicity. This study explores an integrated treatment approach combining constructed wetland-based remediation with bacterial treatment to effectively degrade methyl orange and other pollutants in textile wastewater. Textile wastewater was collected from Bhadohi Nagar Palika, Uttar Pradesh, India, and subjected to physicochemical analysis. The initial wastewater exhibited a pH of 9.6 ± 0.12, biochemical oxygen demand (BOD) of 1008 ± 0.75 mg/l, and chemical oxygen demand (COD) of 2035 ± 0.61 mg/l, all exceeding Central Pollution Control Board (CPCB) standards. An 80-liter constructed wetland system planted with Typha latifolia and Phragmites karka was implemented, followed by bacterial treatment. The integrated system reduced the pH to 7.21 ± 0.38, BOD to 54 ± 0.25 mg/l, and COD to 134 ± 0.74 mg/l. Fourier transform-infrared (FTIR) analysis and gas chromatography-mass spectrometry (GC-MS) confirmed significant reductions in organic pollutants and dye components. Additionally, 16S rRNA gene analysis identified key bacterial strains contributing to biodegradation, including Enterococcus faecium and Bacillus subtilis . Further, the treatment system also achieved a notable shift in methyl orange dye absorbance from 538 nm to 201 nm, indicating substantial decolorization. These findings demonstrate the potential of combined wetland and bacterial treatment for effective remediation of textile wastewater.