Advanced oxidation of textile wastewaters

Model dyeing and laundering wastewaters produced during two basic technolog ical operations of the textile industry were subjected to treatment by adva nced oxidation processes (AOPs). The following agents were used: ozone (O-3 ), hydrogen peroxide (H2O2) and UV radiation. They were applied separately and in all possible combinations: O-3 + UV, O-3 + H2O2, UV + H2O2, as well as all three at the same time: O-3 + UV + H2O2. Effluents before and after the treatment were analyzed according to requirements of the Polish Standar ds that included pH, color threshold, COD and concentration of anionic and non-ionic surfactants. Ozonation was carried out in a lab-scale bubble colu mn reactor with a centrally located UV burner. The most effective version o f AOPs proved to be the simultaneous use of all three agents. In the case o f such treatment of dyeing wastewaters nearly complete discoloration and fu ll decomposition of surface-active substances were obtained at 80% reductio n of COD. A similar tendency was observed in the case of laundering wastewa ter, though in that case the results were slightly worse, which may be expl ained by much higher initial concentrations of the pollutants. Good treatme nt effects have also been obtained in combined treatment by simultaneous us e of hydrogen peroxide and ozone.