| Recently, with the development of nylon, colophony, membrane and leatheroid in the area of engineering plastic, the demand for CPL is increasing. In our country, for many years, the output of CPL could not appease the market demand. In the last few years, the output is only 1/3 of the actual consumption and presently, 1/2 of the actual consumption. According to some expertise, in the year of 2005, the supply of CPL will reach 295,000 tons but the demand will reach 410.000tons. There will be a shortage of 115,000tons. It is urgent to develop the industry of CPL in our country now.Though the waste water of CPL is biodegradable, the component of the waste water is very complicated and the content of nitrogen is very high, the water is actually hard to degrade. Active sludge treatment, which is representative of the traditional aerobic biological treatment, has been widely used in the treatment of living and industrial waste water for many years. But if it used in the treatment of CPL waste water, the NH4+-N and TN in the treated water can not reach the standard. On the contrary, MBR (Membrane Biological Reactor) has the advantage of high remove efficiency, good nitration effect and it can run under high volume load, low sludge load and lasting sludge age. It can appease the treat requirement of CPL waste water.In this research, firstly, the treat efficiency of MBR A/O process and CAS A/O process of simulative CPL waste water is compared. The advantage of MBR in ordinary sludge concentration is studied and the effect of membrane modules on the treat efficiency and its mechanism is analyzed. Through the comparison of the characteristic of the sludge, the growing condition of the microorganisms in the tworeactors is observed. Then the treat efficiency of simulative CPL waste water in MBR system under various condition is specially studied. The parameter of HRT, sludge age, organic load, DO, R are changed one by one and under each changed condition, the treat efficiency is studied and we find out the optimal condition to attain both the system stabilization and high treat efficiency.The characteristic of the microorganisms in the MBR system is also studied. The metabolizability characteristic of the microorganisms during the process is analyzed through the OUR /SOUR test and the viscosity of the sludge.Finally, the separation characteristic and the control of membrane pollution is pilot studied. The effect of various condition of HRT, pump period and aeration intensity on the separation characteristic of the membrane is studied and under each condition, the membrane resistance is calculated. The change of membrane flux after physical and chemical cleaning is compared through water test and both Rm and Ref is calculated. Based on these analysis, the effective ways of slower membrane pollution are discussed.As the research has shown, SMBR has high remove efficiency and the quality of treated water is stabilized. There is no suspended solid in the treated water and the turbidity is near zero. The separation of solid and liquid in the MBR system is high efficiently and far better than CAS system. The MBR system retains high sludge concentration and the volume load is high and the sludge load is low so the system occupies less area. MBR system runs under high volume load, low sludge load and long sludge age, which create a good condition for the propagation of the nitrification microorganisms. The system efficiently removes the NH/-N and has high nitration efficiency. It is a newly efficient process for the treatment of CPL waste water. |
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