Study On Treatment Of The Yellow River Source Water With Sludge Suspension Clarification Filter

Ultrafiltration is the core of the third generation of drinking water treatment technology,its application can not only reduce the use of water treatment chemicals,and also to enhance the water quality of biological safety and chemical safety.Ultrafiltration is the best choice of the current domestic and foreign water treatment plant design and technological transformation.Sludge suspension type clarifier is combined coagulation with sedimentation into one of the water treatment process that with a short process and mall footprint,etc.It has more applications in the urban drinking water treatment.But it has worse adaptability to changes in water quality,it has large fluctuations in water turbidity and it increase the follow-up filter load.In this paper,it joined ultrafiltration membrane in the sludge suspension type clarifier to form a sludge suspended ultrafiltration clarifier.Liujiaxia Reservoir is the second drinking water source of Lanzhou.The water quality is good and the degree of pollution is light.It raised the treatment technology with ultrafiltration as the core because of the characteristics of low temperature and low turbidity in Liujiaxia reservoir in winter and spring.And it used the immersed polyvinylidene fluoride(PVDF)and polyacrylonitrile(PAN)membrane.It took sludge suspended ultrafiltration clarifier,direct ultrafiltration process and coagulation sedimentation ultrafiltration(coagulation ultrafiltration)to deal with the low temperature and low turbidity of Liujiaxia Reservoir.The effects of the sludge suspended ultrafiltration clarifier were studied on the water quality of normal temperature and high turbidity water,normal temperature and low turbidity water as well as low temperature and low turbidity water on Lanzhou section of the Yellow River treatment efficiency and membrane fouling,and the effects of sludge suspended ultrafiltration clarifier load were studied.The main conclusions are as follows:(1)The conditions of Liujiaxia Reservoir water quality are superior and low turbidity.The quality of water on Yellow River Lanzhou section has bigger change on the turbidity in a year.the general situation Liujiaxia reservoir water and Lanzhou section of the Yellow River water temperature is not higher than 20 ?.The two kinds of water quality contained the concentration of dissolved organic matter is low and close,the species is similar and all are mainly hydrophobic organic matter.(2)The results show that the turbidity of raw water is mainly removed from the suspended sludge layer in the ultra filtration tank through the flotation of sludge suspension in the Lanzhou section of the Yellow River.The ultrafiltration membrane can ensure the effluent turbidity is less than 0.2NTU,the removal rate is not less than 98%.The removal efficiency of 15%-48% in the raw water permanganate index(CODMn)was better than that of the slurry flotation clarification filter,and the removal efficiency of CODMn was better in the condition of high turbidity.The removal of turbidity and organic matter in the clarifier can effectively reduce the pollution of ultrafiltration membrane.(3)The treatment effect of low temperature and low turbidity of Liujiaxia reservoir water: sludge suspending clarification super filter process better,coagulation ultrafiltration process,direct ultrafiltration is the worst.In the three processes,the sludge flotation is the only way to clarify the membrane fouling.When the attenuation of membrane flux almost stopped when the sludge suspending clarification membrane filter process than PAN flux and PVDF membrane flux than coagulation ultrafiltration process were improved by 63.2% and 66.7%.(4)The membrane filtration resistance of direct ultrafiltration and coagulation ultrafiltration is mainly based on concentration polarization resistance.And the residue of slurry is clarified to filter the cake layer resistance.The total resistance of ultrafiltration membrane filtration: direct ultrafiltration + coagulation ultrafiltration slag flotation clarification ultrafiltration.The total resistance of PAN membrane and PVDF membrane was decreased by 76.52% and respectively compared with the total resistance of the ultrafiltration UF membrane.Ultrasonic cleaning and chemical cleaning methods had the best effect on the recovery rate of ultrafiltration membrane.In the three processes,the lowest operating cost of sludge suspension and clarification of the ultra filtration.