Research On Wastewater Treatment Technics Of Machining Emulsified Oil And Its Application

In the machining process, the emulsion was used as a lubricant and coolant. The emulsion oil particles have 0.1 ~ 0.3 and disperse in water. After it is long loop in the systems, the emulsion oil changed into a emulsion oil wastewater by bacteria and microbial erosion. The emulsion wastewater has emulsifying strong stability, high concentrations of organic, high oil content, high chroma, intermittent discharge less and difficult to degradation by biological characteristics. Therefore, the high concentration of emulsion oil wastewater treatment, environmental protection has always been an important research topic by domestic and foreign researchers are highly valued. Over the past decade, much research has carried out for high concentration emulsion oil wastewater, the scope of the study, involving almost physical, chemical and biological method of treatment, but due to technical, economic and other limitations, at present most of them have not yet been applied in industry.In this paper, Shenyang Aerospace Mitsubishi Motors Engine Manufacturing Co., Ltd. sewage treatment station as the basis, according to the machining characteristics of emulsified oil wastewater, the combination processes of the emulsifications + film filter + Fenton reagent oxidation and Biological filter was used for treat the engine production emulsified oil wastewater of high concentration. The research to explore effective ways of pollution treatment has important theoretical significance and application value.Emulsion containing a large number of oil and surfactant has considerable stability. The key to dealing with waste emulsion is emulsion breaking, both demulsifier selection of species, through small emulsion breaking agents and find the best dosage. The screening tests, with 15% PAC demulsification the best, the same concentration of PFS results slightly lower than the PAC, but considering the PFS is only about half the price of the PAC, other processing equipment with PFS pipeline corrosion and other factors. Therefore, the selected combinations of PFS and PAM for breaking waste emulsion, flocculation treatment, COD removal rate can reach 80%.Demulsification concentration after the emulsion is still up to 10000mg / L, thus microfiltration process was used further. The principle is to retain microfiltration filter, all while the volume ratio of micro-membrane pore size larger particles can get through, as used in Microfiltration with 2mm thickness and water flow rate through the membrane on the low, so the microfiltration process are the characteristics of deep bed filtration, that is part of the membrane pore size smaller than some of particle will be removed. Through microfiltration membrane filter, the COD removal rate is about 30%.After Demulsification and filtration, the COD of emulsified liquid is as high as 4000mg / L or more. Simply mixed with sewage water can not meet requirements of biological filter, further reducing the wastewater COD, enhance biodegradability, so the introduction of Fenton Reagent Advanced Oxidation treatment. The experimental showed: the water COD4000mg / L, the optimum reaction conditions: temperature is 40 ~ 50℃, pH is 2.5, Fe2 + is 4mmol / L, H2O2 is 60 ~ 80mmol / L, reaction time is 2 ~ 3h. The experimental observation, advanced oxidation can remove 50% COD, to ensure that the wastewater and domestic sewage mixed water to the BAF's water requirements.Mixed wastewater entering the biological treatment plant, taking the company sewage treatment station is constraints by site, and the daily treatment capacity is not much, consider working more powerful functions, small size, operating stability, so high capacity advantages of aeration Bio-ceramic filter (BAF) is selected. When the pretreatment of wastewater and the cutting fluid mixture of water, biological water treatment. BAF can not only effectively remove CODcr and suspensions, but also for efficient nitrogen and phosphorus removal, it also has a high load, shock ability. The two BAF can be removed about 90% of COD.The observation of the actual operation, the emulsion waste treatment plants can discharge machining line COD was 50000 ~ 200000mg / L, oil 20000 ~ 30000mg / L of waste emulsion, treated as COD <50mg / L, oil <5mg / L level, water quality can meet the "Liaoning Province, the effluent standards" (DB21-60-89) in the new extension to change a standard. Successful implementation of this system to find a suitable machining of high concentrations of emulsified oil wastewater treatment program to provide an optimized process and reasonable design parameters for the future sewage out of the industry to provide valuable reference.