Color and dissolved organic carbon removal from textile industry wastewater through oxidation and electrocoagulation

Electrocoagulation in combination with an oxidizing agent is a very promising process for the treatment of water in the textile industry. In the present study, an experimental design was carried out to compare the influence of oxygen and ozone as oxidizing agents, in the removal of color, UV and dissolved organic carbon (DOC) present in textile wastewater of industrial origin. The results show that there is no significant difference in the removal efficiency of true color, DOC and UV when both oxidants are used with electrocoagulation, with average values of 88.7% +/- 2.5%, 49.7% +/- 3.6%, 28.5% +/- 3.4%, respectively. The amount of iron generated by electrocoagulation, and its complete precipitation by oxidation in the presence of air or ozone, are the key factors for the removal of contaminants. This indicates that the process is carried out by adsorption of organic matter on the iron precipitates and not by its direct oxidation with ozone, with the advantage that the oxidation of iron with air is cheaper than with ozone. ANOVA analysis of the design of experiments showed that the applied current has a statistically significant effect on DOC removal, but not on color and UV removal.