PHOTOCHEMICAL ELIMINATION OF PHENOLS AND COD IN INDUSTRIAL WASTEWATERS

It is demonstrated that toxic pollutants such as phenols in industrial wastewaters can be eliminated efficiently by photochemical methods us ing a combination of UV and heterogeneous photocatalyst, and combinati ons of UV, H2O2, and ferric compounds. The combination of UV and photo catalyst even decreases the COD of some of the toxic industrial wastew ater around 60-70% in 1-4 hour treatment time depending on the source of the wastewater. The different combinations of UV (200 W high pressu re mercury lamp, wavelength 313 less than or equal to lambda less than or equal to 456 nm), magnetite or aluminium oxide (as photocatalyst), H2O2 and iron compounds (FeCl3, Fe(NH3)2(SO4)(2), as Fenton reagent) were used in lab scale experiments to examine the elimination at aerat ed conditions of pure phenol in solutions (initial concentration = 25 ppm) and of substituted phenols and COD in industrial wastewaters orig inally from phenolic resin manufacture, oil refinement, shale oil dry distillation, and naphthenic acid production. The results clearly show the separate and combined effect of UV, Ferric compounds and H2O2 on the elimination of phenols and COD. (C) 1997 IAWQ. Published by Elsevi er Science Ltd.