Bacterial degradation of electrochemically oxidized textile effluent: Performance of oxic, anoxic and hybrid oxic-anoxic consortium

This study investigates the biodegradation of electrochemically pre-treated textile effluent. The duration effect of electrochemical oxidation (EO) on enhancement of biodegradability and the biodegradation efficiency on untreated and electrochemically pre-treated effluents were evaluated. The EO pre-treatment was performed using Ti/TiO₂-RuO₂ as anode and Ti metal as cathode. The biodegradation was carried-out using oxic, anoxic and hybrid oxic-anoxic consortia. The increase in the duration of EO pre-treatment resulted in the decrease in the duration of biodegradation. The biodegradation kinetics (Grau's second order rate) has shown that the oxic-anoxic consortium was 3-fold faster than oxic consortium in EO pre-treated effluent. Complete COD removal (<25 mg L⁻¹) and >90% of TOC removal were achieved by the combined electrochemical and oxic-anoxic biodegradation system. The role of Nitrincola sp. in the oxic-anoxic consortium was reported for the first time using metagenome analysis. The oxic-anoxic consortium was enriched with both O₂ dependent classical aerobic pathway and NADP-dependent benzoyl-CoA oxidation pathway.