Combining ultrasonic treatment and ozonation for wastewater treatment of dyeing plants

Summary

The results of studying the efficiency of purification of model and real wastewater from dyeing and finishing works by combining ultrasonic treatment and ozonation are presented. The effect of the treatment time, ozone concentration in the gas mixture on the purification efficiency has been studied. The purification efficiency was evaluated by optical density and COD. As a result of the study up to 12% increase in the efficiency of wastewater treatment was shown while combining flotation with ozone-air mixture instead of air with ultrasonic treatment. This effect can be associated, first of all, with the dispersion of ozone-air mixture bubbles that results in an increase in the surface area, and, accordingly, in an increase in the kinetics of mass transfer – ozone dissolution.

Key words

flotation , wastewater , dye , ozone , fabric dyeing

Flotation of wastewater from dye works using ozone

Summary

The results of experimental studies of the efficiency of purification of model and real wastewater from dye and finishing works with the aid of pneumatic flotation using ozone-air mixture instead of air are presented. The effect of the gas mixture flow rate, dye concentration, and ozone concentration in the gas mixture on the purification efficiency was studied. The purification efficiency was evaluated by optical density and COD. While using ozone-air mixture instead of air, a 12-fold efficiency increase was achieved. The results of the studies have shown that while using ozone flotation to achieve the purification efficiency of 90% of the real wastewater from dye and finishing works, abstracted upstream the treatment facilities (electrocoagulation followed by flotation), the following conditions are required: processing time not less than 60 minutes; consumption of ozone-air mixture not less than 5 l/(l·min); ozone concentration in the ozone-air mixture not less than 8 g/m³.

Key words

wastewater , flotation , dye , ozone , fabric dyeing