Performance of Combined Process of Air Flotation- Sedimentation - Biological Contact Oxidation - Membrane Biological Reactor Treating Heavy Oil Wastewater

Abstract

A study of the treatment of heavy oil wastewater was carried out using the combined process of dissolved air flotation-sedimentation- biological contact oxidation - ultra-filtration membrane. When hydraulic retention times (HRT) was 18h, removal rates of COD, oil and suspended substance (SS) approached at 73~75%, 98%~99% and 100%, respectively. The diversity of bacterias was increased after air flotation, the betaproteobacteria dominated after enriched bacterias of BW-1， BW-2， BW-3，WSW-4,1-2-1 and 3-2-1 were added to contact oxidation tank. The combined process provided a suitable process in dealing with the complex heavy oil wastewater.