Estudio de la degradación de colorantes azoicos mediante la combinación de un proceso de ozonificación con un proceso biológico aerobio para el tratamiento de un efluente textil

Abstract

The present research studied the degradation of the azo dyes Drimaren Blue HF-RL, Yellow Drimaren Cl-2R and Direct Red 4BS. It was analyzed the influence of pH on a synthetic dye mixture and on a textile effluent whose physicochemical parameters didn’t comply the discharge limits to natural water sources. The ozone dose was determined to achieve a degree of biodegradability that would allow to apply an aerobic biological process. The highest percentages of color removal in the synthetic dye mixture were obtained with a pH value of 10 when the doses of ozone were lees of 0,008 mol O3/L, but a pH of 8 was selected when the doses of ozone were 0,008 mol O3/L or higher. For the treatment of the textile effluent, the pH of 8 and the dose of 0,012 mol O3/L were selected; a BOD5/COD ratio of 0,43 was achieved. The biological process was developed with a flow rate of 3 mL/min. The combination of ozonation and aerobic biological process achieved removals of: 75,78 % of TOC, 92,16 % of color, 92,10 % of BOD5, 94,63 % of COD, and 91,13% of surfactants; a subsequent sedimentation allowed to obtain 91,00 ± 15,87 mg/L of suspended solids and 1 242,00 ± 83,05 mg/L of total solids, complying with the environmental regulations.