Pilot Study On Coagulation/Ultrafiltration And Analysis Of Membrane Fouling

Application of UF membrane technology to drinking water treatment offers many advantages such as low turbidity of treated water and small footprint. Low Organic matter removal rate and membrane fouling are two key problems. The membrane combined with coagulation is able to increase Organic matter removal rate and prevent membrane fouling. In this study ,pilot experiment was conducted at Yanling drinking water treatment plant ,a spiral UF membrane that had experienced long-term filtration was also investigated .Based on the results obtained in this study ,it was discussed how to increase removal rate of organic matter and prevent membrane fouling.The following conclusions can be drawn from the pilot experiment. 1. Coagulation with sedimentation /UF and in-line coagulation/UF hybrid process were used in the pilot experiment at Yanling drinking water treatment plant. The membrane fouling of UF was prevented in the in-line coagulation/UF hybrid process. When filtration mode was dead-end and membrane flux was 1.6 m/d, TMP increased from 0.025MPa to 0.035MPa in 66 days . Dosing PFS 1.5 to 30 mg/L (in Fe) or PAC 4 mg/L(in AL) ,UF membrane is stabilized. After pretreatment of coagulation with sedimentation, TMP increased from 0.02MPa to 0.1 MPa in 2 days when membrane flux was 1.6m/d and from 0.02MPa to 0.07 MPa in 3 days when membrane flux is 1.0m/d.Dosing sodium hypochlorite could prevent membrane fouling to some extent, TMP increased 0.06MP in 15 days when sodium hypochlorite dosage is 3mg/L.2. Raw water and treated water were tested to observe the removal rate of organic matter and metal. In the process of In-line coagulation/UF increasing the dosage of coagulant organic matter removal rate increased .Dosing PFS 30 mg/L COD_Mn and UV₂₅₄ of treated water is 2.6 mg/L and 0.051cm^-1,the removal rate of COD_Mn and UV₂₅₄ is 43%,53.7% separately. Coagulation operating conditions did not affect organic matter removal effect. When PAC dose is 4 mg/L ,UV₂₅₄ removal rate of coagulation with sedimentation/UF and in-line coagulation/UF was 28%,26%...