Integrated approach of photo-assisted electrochemical oxidation and sequential biodegradation of textile effluent

Synthetic azo dyes are extensively used in the textile industries, which are being released as textile effluent into the environment presence of azo dyes in the environment is great environmental concern therefore treatment of textile effluent is crucial for proper release of the effluent into the environment. Electrochemical oxidation (EO) is extensively used in the degradation of pollutants because of its high efficiency. In this study, photo-assisted electrooxidation (PEO) followed by biodegradation of the textile effluent was evaluated. The pretreatment of textile effluent was conducted by EO and PEO in a tubular flow cell with TiO₂-Ti/IrO₂-RuO₂ anode and titanium cathode under different current densities (10, 15, and 20 mA cm^-2). The chemical oxygen demand level reduced from 3150 mg L^-1 to 1300 and 600 mg L^-1under EO and PEO, respectively. Furthermore, biodegradation of EO and PEO pretreated textile effluent shows reduction in chemical oxygen demand (COD) from 1300 mg L^-1 to 900 mg L^-1and 600 mg L^-1to 110 mg L^-1, respectively. The most abundant genera were identified as Acetobacter, Achromobacter, Acidaminococcus, Actinomyces, and Acetomicrobium from the textile effluent. This study suggests that an integrated approach of PEO and subsequent biodegradation might be an effective and eco-friendly method for the degradation of textile effluent.