Removal of salicylic acid from industrial wastewater by ozone

An advanced oxidation process of salicylic acid by using ozone has been studied. A nominal concentration of 80- 100 mgL-1 of the salicylic acid was chosen, which normally occurs in food industry wastewaters. The effect of oxidation concentration and pH on COD and TOC has been studied. It was observed that the highest removing rate of these factors achieved at alkaline and some neutral conditions, i.e., the indirect mechanism of hydroxyl radical attack on the molecule under study. During ozonation of salicylic acid reduction of COD and TOC reached up to 68/89% and 38/65%, respectively. From HPLC peaks, it can be deduced that nearly the whole ozonation intermediates produced during ozonation disappear by 19.1 mg O3L-1 A real sample of wastewater was chosen that contains salicylic acid. Biodegradability of wastewaters, measured as BOD5/COD, increases from 0.43 (untreated wastewater) to nearly 0.97 during ozonation.