Treating Heavy Oil Wastewater for Beneficial Use by Integrated Technology of Bio-Oxidation and RO

Heavy oil exploitation wastewater is characterized by its high concentration of emulsified oil, high salinity, high temperature and complex chemical components. This paper discuss a successful pilot-scale demonstration application of a unique technology integrating heat exchanger, gas floatation, biological contact oxygen, filtration, ultra-filtration, reverse osmosis at Chenzhuang oilfield. The scale of the process was about 360 m3/d, and the performance of the treatment process, the effectiveness of the technology for removal of oil and for controlling RO membranes fouling, and the economic effect are also discussed. Operation results show that the biological contact oxidation--ultra filtration process can reduce the oil contents to less than 0.5 mg/L and TDS to less than 3. The conductivity of RO effluent is below 456 μS·cm-1, the treated water can meet the required standard for steam-injected boiler, and it can also be used to prepare polymer solution for viscosity keeping. Key words: Heavy oil wastewater; Biological contact oxygen; RO; Steam boiler; Polymer solution