Membrane Processes For Reuse Domestic Sewage And Mechanism Of Membrane Fouling In Domestic Sewage Treatment By UF Membrane

Using membrane separation technique for reuse wastewater features it easy operation, equipment compact, safe working environment, low consumption of energy and chemical agent, and qualified quality water can be gotten at different reuse needs as well. Thus great economic and social benefits can be made. Membrane fouling is one of big problem in the application of membrane technology. In order to keep the long-term and stable run effect of membrane parts, it's necessary to study mechanism of membrane fouling. Appropriate mathematical molds of membrane fouling can offer instructions to the optimization of operating parameters by simulated calculation. Accordingly it improve the performance and the life of membrane and the whole system. Membrane processes for reuse domestic sewage and mechanism of membrane fouling in domestic sewage treatment by UF membrane were systematically studied in the paper.The experiment of pretreatment of UF was conducted. The tested pretreatments were MF, GAC(Granular activated carbon), MF-GAC and coagulation, and finally coagulation pretreatment of UF was chosen.The optimum dosing amount of coagulant was determined from the angle of decreasing the filtration resistance of membrane. The result showed that the optimum dosing amount of coagulant which made the minimum resistance was in conformity the optimum value which removed maximum dissolved organic matter and turbidity in domestic sewage.The writer made an overall observation on the effectiveness of coagulation-sand filtration-UF technical process of removing organic matter, total nitrogen, total phosphorus,LAS,NH3-N,organic nitrogen and turbidity in domestic sewage. The drainage quality of UF membrane complete accord with the standard of GBJXX-2001 < to clean toilet and city virescence. The water used to clean vehicle and make cleaning except LAS is slightly off standard, other indicators are all qualified.The scaled pollutant in the course of long-term filtering domestic sewage was analyzed. The result showed that the concentration of dissolved organic matters after being filtrated by coagulation-sand was relatively low and had no obvious effect on long-term fouling of membrane filtration.Membrane was more fouled by inorganic matters which composition were complex. The contrast test showed that adding coagulant did not foul membrane during filtrating period. In the drainage of Shanxi Aluminum factory domestic sewage station, there is higher content of major elements that form the scaled pollutant of membrane.After coagulation-sand filtration-UF pretreatment to drainage of Shanxi Aluminum factory domestic sewage station, the experiment of desalination was made to produce water by UF with small reverse osmosis equipment. The salt content of water produced by RO can be lower than 10mg L-1,thus this kind of water can be used for industry with high requirement for water. This study also made computer simulation and design on the reverse osmosis project of 14250m3/d water.The writer studied that using many kind of chemical agents clean polluted UF membrane, the result showed that good effect of cleaning membrane can be achieved from the alternate use of sodium hypochlorite and acid to clean.This study determined resistance distribution when UF membrane with different pressure, different materials and different molecular weight cut directly filter drainage of Shanxi Aluminum factory domestic sewage station, water produced by coagulation and water produced by coagulation-sand filtration, and gets optimized fouling resistance through comparison.This study uses membrane hole narrowing model(blocking filtration law) and filter cake layer model(cake filtration law)to analyze fouling-control factors during filtering drainage of Shanxi Aluminum factory domestic sewage station, water produced by coagulation and water produced by coagulation-sand filtration by UF membrane with different pressure, different materials and different molecular weight cut.This study established membrane flux mathemati...