| With the problem of water shortage and water pollution worsening, urbanwastewater recycling technology resources become the focus of research in watertreatment technology. The ultrafiltration membrane technology was widespreadconcerned because of its excellent water quality, simple operation, long life and otheradvantages, but the flux decline and shorten the life of the membrane caused bymembrane fouling during operation was the core issues. This paper use the homemadePVDF/PVP improved hollow fiber ultrafiltration membrane as the core unit, combinedwith the coagulation sedimentation and sand filter unit as the pretreatment device for theintegrated treatment processes to treat the urban secondary effluent water. Thisexperiment studies the processing performance of the PVDF/PVP improve overallhollow fiber ultrafiltration membrane separation systems,analysis the pollution capacityto the ultrafiltration membrane system of different pollutants in urban secondaryeffluent water, and optimize the operating conditions of different ultrafiltration fluxcondition based on previous research. The main conclusions were as follows:(1) Using the TOC and UV254value as a representative parameter characterizingthe organic molecular weight of wastewater effluent in winter and summer. In winter,when use the TOC to characterize the result, the organic matter of <10kDa was64.31%,the organics things of>100kDa was15.49%; when use the UV254to characterize theresult, the organic things of <10kDa was71.05%, the organic things of>100kDa was9.21%. In summer, when use the TOC to characterize the result, the organic things of <10kDa occupied69.73%, the organic things of>100kDa occupied10.96%; when usethe UV254to characterize the result, the organic things of <10kDa was74.02%, theorganic things of>100kDa was5.51%in UV254. From the result we can found that mostof the soluble organic matter was small molecules, and small molecules material hasincreased in summer.(2) Pretreatment system including coagulation device and sedimentation deviceand sand filtration device, and the ultrafiltration membrane as the core unit, the turbidityis reduced to0, the UV254reduces34.82%, the average remove of the COD was32.97%,the PO43-reduces was29.57%, and the NH4+reduces31.08%. And the pretreatmentsystem enables turbidity reduces93.01%, the UV254reduces23.06%, the COD reduceswas26.03%,and the reduces of the PO43-was25.22%, and the average remove of theNH4+was26.1%. During the Ultrafiltration operation, the membrane water quality wasstability. The effluent of membrane water value on the turbidity is0, UV254is0.074~0.088cm-1, COD is14.64mg/L~29.18mg/L, ammonia nitrogen is0.48~0.98mg/L, and phosphate is0.34～0.87mg/L. Membrane effluent water fix the industrialcooling quality indicators of Urban Recycling of Industrial Water Quality.(3) Using the microscopic force to analysis the turbidity and organic matter ofurban secondary effluent on the ultrafiltration membrane fouling analysis. The pollutionof ultrafiltration tests showed that the organic matter was the main causes of membranefouling, and the organic pollution of ultrafiltration stronger than the turbidity. Theatomic force results show that the adsorption capacity of organic matter of turbidity wasgreater than the ultrafiltration membrane, the presence of turbidity in water wasadvantage to improve ultrafiltration membrane of organic matter removal capacity.(4) According to preliminary research group studies, the test optimized the controlconditions of the ultrafiltration membrane under different flux conditions. The resultshows that at the water production flux was50LMH to80LMH, control the backwashflow was2.5times as the filter flow and the fast wash flow was2.5times as the filterflow, combined with the dosing backwash can effectively control the growth oftransmembrane pressure and achieve the long-running ultrafiltration membrane. |
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