Catalytic wet oxidation of real process wastewaters
CWO and WO were carried out for oxidizing different industrial wastewaters of pharmaceutical production, at 230 o C and 250 o C and total pressure of 50 bar, with oxygen, in stainless steel autoclaves. The catalysts were titania supported precious metal (Pt, Pd, Ru, Rh) oxides and copper sulfate. Samples were analyzed with respect to their TOC, COD (BOD) content. The tested wastewaters, some of them mother liquors, could be oxidized, but with rather different conversions. Even at the hard-to-oxidize wastewater the COD decrease hit the 50 % during 4 hours, this procedure decreased the COD/BOD ratio. The Ru oxide-titania catalyst proved to be the most active in this process, yet in the non-catalytic reactions significant conversion was detected also, due to the Fe or Cu ion content of the wastewaters.