Application of electroc hemical processes in aerobic biological systems used for textile wastewater treatment: effects on mixed liquor characteristics and pollutant removal

This study evaluated the influence of electrochemical process application on pollutant removal and changes in the characteristics of mixed liquor in aerobic biological systems used for textile wastewater treatment. For this purpose, samples of mixed liquor containing synthetic textile wastewater (nitrogen, phosphorus, acetate, and Drimaren Red CL-7B dye) were introduced into bench-scale reactors operated under two experimental conditions: in the first condition, the application was performed with a current density of 20 A m⁻², using an intermittent exposure mode of 6 min on / 30 min off (Strategy 1 – S1), while in the second, the same current density was applied but under continuous exposure (Strategy 2 – S2). A control reactor was operated simultaneously for comparison purposes, evaluating pollutant removal and the filterability of the mixed liquor. The results indicated that electrochemical processes improved the filterability of the mixed liquor by 35% in S1 and 44% in S2. Dye removal ranged from 40 to 50% in the control reactor, reaching 67% in S1 and 93% in S2 with the application of electric current. Regarding phosphorus, the application of electric current increased removal from 30% in the control reactor to 67% in S1 and 96% in S2. No significant changes were identified in the content of total suspended solids with intermittent application. However, under continuous exposure, an increase of approximately 30% was observed. It was concluded that the application of electrochemical processes can be a promising alternative to enhance the performance and stability of biological treatment systems applied to textile wastewater treatment.