| Recent years, the sanitary sewage and the industrial wastewater dispersed into the water body, the water resources pollution is serious. The water shortage and pollution causes taking the secondary outlet into reuse. At present, the secondary depth treatment mostly use coagulation sedimentation, sand leach, activated carbon adsorption and so on, which have many disadvantages. The membrane separation technology is recently recognized, and may be used at large. But there are many problems in membrane separation technology application process which have not been solved, like realization of highly effective low consumption separation process and membrane pollution. The membrane pollution research has the vital significance to the promotion of membrane separation technology.In this study, the secondary effluent of Bei Shiqiao wastewater treatment plant in Xi'an was used to perform bench-scale ultrafiltration (UF) experiments. Uses different method, Changes the original water character (for example, the pH value, ionic strength and bivalent metal ions) and separate the hydrophilic and hydrophobic DOM, discusses the influence of solution environment to ultra- film flux. Using the model of membrane aperture and membrane hole density along with water percolation flux change, discuss the influence of different solution environment to membrane aperture and membrane hole density change. The results showed that:(1) The influence of original water pH value to ultra film flux: Under the low pH condition, the primary pollution in the initial period of filtration is cake, rapidly has the pollution, causes the sharply decline of flux;in the later period, the membrane flux depression has slows down. Regarding the pH high situation, have no obviously cake formation, the membrane pollution is always in the interior, therefore the flux decline slowly in the initial period, but intensifying in the last period..(2) The higher of ionic strength (counts by NaCl), the more serious of membrane flux depression, the membrane pollution is correspondingly fiercer. Under high ionic strength, Because of double-decked compression and electric charge shielding effect, The electric charge on membrane surface and thehumus macro-molecule obviously reduces, Causes reduction of electrostatic repulsion between the membrane surface and the DOM, Thus, DOM precipitates to the membrane surface speeds up, This is in turn causes the cake changing thick..(3) The influence of bivalent ions: as a result of the Ca2 + complexing action, the electrostatic repulsion between the DOM chains reduces, Makes it easier to connect forms coils around the shape humus macro-molecule. Therefore, the pollution rate and degree of DOM increase remarkably along with the Ca2+ density increase.(4) The influence of hydrophilic and hydrophobic DOM is: The reason of flux decline is the hydrophobic DOM, the hydrophobic DOM directly influence surface adsorption, the more hydrophobic DOM, the bigger adsorptions.(5) The influence factor a, and a2 calculated by the model indicated that, a, of the CaCh adjustment water sample is the smallest which related to Ca2+ complexing ,Causes the organic matter transforms from the small member to the macro-molecule. a2 oftheNaCl adjustment water sample is the smallest because the membrane pollution is primarily the membrane hole block, the membrane hole density reduces obtains alleviates.
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