Research On Advanced Treatment Process Of Coal Chemical Wastewater Membrane Method

With the development of the society, the lack of water resource in our country is serious, coal chemical industry as the basis of the chemical industry in China’s not only need to consume large amounts of water resource, and the amount of the emissions of waste water is very large, the locations are concentrated mainly in coal producing area, which are generally lack of water resource. Therefore our country must advocate reducing emissions of sewage, or zero emissions. Wastewater from coal chemical industry as industrial wastewater has the typical characteristics of the industrial wastewater, which contains a high concentration of refractory organic compounds. So by the simple processing of primary and secondary, the hardness, ammonia nitrogen, COD and other indicators of the water are difficult to meet the criteria of emissions and recycling requirements. Obviously, in order to meet the requirements of recycling and zero discharge, the depth of the coal chemical industry wastewater treatment is imperative.In the deep treatment of coal chemical industry wastewater process, must use separation technology, membrane separation technology of it is the most innovative and development potential. Used for the treatment of coal chemical industry wastewater, membrane separation technology has been use, and widely used technology is UF-RO, but actually found in the process of using the technology of reverse osmosis process exists many problems, including high operating pressure, membrane is easily blocked, the quantity of high concentrations of water is large, water production rate is low. However, in the UF-NF process, stress can ease but brings obstacles for the removal of monovalentons. Based on the comprehensive analysis of the above, used the depth of the coal chemical industry wastewater treatment process as the breakthrough point, we put forward the UF-NF-RO of this new technology. The technology in this field is still in development period, there are many key factors remains to be further discussed.This article has carried on the grope of UF-NF-RO process, its effect on the depth of the coal chemical industry wastewater treatment is studied, and research if the process is stability, and then through the UF-RO process in the experiment, we do the contrast research, finally through the analysis of nanofiltration and reverse osmosis, we can judgment and summary the pollution characteristics of membrane from the effect of organic residues of chemical wastewater.The experimental results show that the coal chemical industry wastewater of secondary treatment applied UF-NF-RO governance process, which bring that operation is stable and the water quality is satisfactory after treatment:After ultrafiltration, SDI of water keep under 3, and the turbidity removal rate of 90%; after nanofiltration, the turbidity of water is below 0.1 NTU, and hardness removal rate reached 72.37%,50% of COD removal, in addition the influence of raw water quality was not too big; The three major indexes of removal rate (COD, hardness, electrical conductivity) of water from reverse osmosis is over 99%,99% and 98% respectively; After dealing from water system, the water quality can fully meet recycling standards, and there is no chemical cleaning process in the running. Removal rate of UF-NF-RO system show that COD is over 90% and desalination rate is 90% respectively. CoMPared with the former, the overall effect is not better. Nanofiltration and reverse osmosis as the key technology part of such a system, we study this carefully, then analysis and discussion, the result indicated that the molecular weight of decomposition of organic matter is mainly less than 5 kDa. Nanofiltration membrane stop the organic matter with the molecular weight of 100 kDa～50 kDa and less than 5kDa. Obviously the beginning of the filtering effect can protect the reverse osmosis membrane to prevent its fast pollution. There is no doubt that this research can lay a solid foundation for reaching recycling and zero emissions targets of the coal chemical industry wastewater.