| Water is the source of life on earth and the only irreplaceable natural resources. With the rapid development of economy, water pollution and environmental deterioration had been seriously constrained the development of our country, protection and effective management of water have become the most serious challenges of our country.As a strengthen measure of sewage treatment technology, the coupling of magnetic technology with activated sludge, anaerobic fluidized bed technology and artificial ecosystems, in practical applications achieved gratifying results.In order to explore the mechanism of magnetic fields enhanced degradation and apply magnetic technology for the next step in wastewater treatment, in this paper Magnetic Fields Enhanced Biodegradation-High Gradient Magnetic Separation (shorted by MFEB-HGMS) complex process is initiated. The treatment scheme is discussed and probed in detail, in which the magnetic field can enhance the degradation efficiency of microbion in the actual wastewater treatment. This research gives firsthand data supporting the consequent research of the development and application of the magnetic field technology in waste water treatment process.In the research, the activated sludge taken from the sewage is acclimated and cultivated in magnetic field, and then isolated and purified. By mixed bacterium, the magnetic field enhanced biodegradation process carried out in a detailed experimental study. Three wastewater samples which come from: Synthetic sewage, Qing Nianhu and Wei Jinhe are studied.The optimum biodegradation conditions for wastewater such as time, intensity of magnetization, temperature, pH and initial concentration of CODCr, are confirmed. In addition, theoretical analysis finds that the influence of the magnetic field about the changes of material energy, free radical reaction, enzyme activity and biofilm permeability will be the mechanism of magnetic enhanced biodegradation.Separation of bacteria and suspended substance from waste liquid was studied using high-intensity high-gradient magnetic separator with nickel wires. The result indicates that the higher the magnetic field strength and the longer the duration, the better separation effect.The optimum separation conditions for the wastewater such as the different forms of nickel wire, magnetic induction, packed ratio of nickel wire, liquid flow rate, temperature and reuse frequency of nickel wire are confirmed. The result also indicates that the treatment effect is the best when the nickel wire paralleled the direction of water flow, the temperature has no impact on the separation, the higher the magnetic induction, the slower the velocity , the greater packed ratio of nickel wire, the fewer reuse times, the better separation effect. In addition, calculation and analysis find that it needs 188Gs to separate the bacteria or suspension in the high gradient magnetic separator. There will be induction current in the bacteria triggered by electromagnetic induction. When the current reached a certain threshold it will damage cells, change the way that ions through the cell membrane or denature protein, and then bacteria won't be survived.At last, the actual wastewater is treated by the MFEB-HGMS comprehensive technology continuously under the optimum operation condition. Wastewater is treated in the enhanced stage for 48 hours with 200Gs and in the separation stage for 7 days with 6000Gs, 4.25cm/min and packed ratio of nickel wire is 12.0%. Use the MFEB-HGMS processes.The quality of purified liquid is CODCr16.38mg/L and TP 0.047 mg/L, which meet theâ…¢category of the state environmental quality standards for surface water and C standards of water quality standard for scenery and recreation area.
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