Mbr-of Baf Processing The Produced Wastewater

The amount of crude oil that is recovered in Liaohe Oil Field each year can reach 1.5 107 ton. However, with the development of the oil recovery technology and the exaltation of the crude oil yield, the amount of the accompanying wastewater (produced water) begin to increase year after year and the arbitrarily discharged wastewater has caused serious environmental problem.The main object of this paper is to design a set of rational technological process that is suitable for produced water to achieve environmentally acceptable disposal of this kind of water. On the basis of current produced water treatment methods, we took the technological flow - "air-floatation (adding chemical) - MBR - BAF -discharging" to treat produced water from Xingyilian (the name of an oil recovery site) and obtained satisfactory results.In laboratory experiment, we observed the properties of the sludge during cultivation (discontinuous influent mode) and took the concentration values of pollutants in the supernatant fluid which had been treated by microbes as the indication of domestic active sludge. And since the set of devices had began to run steadily (continuous influent mode), we reviewed the disposing effect of the pollutants and the state of the membrane. From the experiment, we concluded that when the COD of raw water was about 400 mg/L, BOD 80-100 mg/L, SS about 100 mg/L and oil content about 50 mg/L, the rate of COD removal could reach 80%, and removal of BOD, SS, oil content were all above 90%, effluent could be discharged to surfaces directly. And HRT = 10h was the best working parameter for the system, under which decent removal effect could be achieved and also the membrane kept fine state.On the basis of laboratory experiment, we carried on field pilot-plant-scale test (disposal quantity was 1 m3/h). After the sludge cultivation, the system was operated with the parameter of HRT =10h, achieving effluent with following characters -COD was about 90mg/L, BOD was about 2-3 mg/L, SS, NH3-N and oil content were all less than 1 mg/L. The quality of the system effluent could fully fit the national required discharged wastewater quality.