Effects of ozonation on COD elimination of substituted aromatic compounds in aqueous solution

The chemical oxygen demand (COD) change of various substituted aromatic com pounds, namely benzoic acid, p-aminobenzoic acid, p-toluenesulfonic acid, s ulfanilic acid: nitro benzene, resorcinol, p-cresol, o- cresol, o-toluidine , aniline and 8-hydroxyquinoline were investigated at ozone doses of 5, 10, 15 and 20 mg O-3. min(-1), respectively. Percent COD removal of initial co mpounds after ozonation was compared with reported biodegradation results. The pH change and percent removal of selected compounds were also evaluated in ozone does of 20 mg O-3. min(-1) up to 80 min. ozonation. The results s howed that high ozone doses are needed to obtain better elimination of init ial compounds and also to improve further degradability of the ozonation pr oducts.