Effect Of Ozone On Organic Matter During Ultrafiltration Membrane For Surface Water

Low-pressure membrane,an alternative of conventional water treatment process,has extensive prospect.However,membrane fouling is becoming a main problem when membrane technology is used in the water treatment.Studies have shown that organic matter is the major membrane foulant.Therefore,organic matter removed effectively is one of measures to control membrane fouling.This project,Qiantang River used as study object,focused on control of membrane organic fouling of ultrafiltration membrane for treating surface water.Basing on survey of organic matter in the Qiantang River,membrane filtration characteristics and membrane permeate quality during ultrafiltration membrane for Qiantang River were investigated.Moreover,the effects of ozone on organic matter and membrane fouling were conducted and mechanism of mitigating membrane fouling was illuminated.The results showed that organic matter mainly focuses on lowmolecular weight and hydrophilic organics in the Qiantang River.With the increasing of contact time of ozone,the removal efficiencies of UV254 werehigher than that of DOC during the range of 0.5~20min contact time.Ozone can decompose high molecular weight organics into low molecular weight ones and enhance hydrophilic fraction of organics.The combination of ozone and membrane can further improve removal of organic matter.The membrane specific flux increased with the increasing ofozone contact time,and there exists an optimal contact time of 5min to make membrane flux maximum.During this contact time,the matter structure of membrane surface was loose and membrane resistance was the smallest.It is found that membrane fouling caused by humus acid and fulvic acid can be alleviated by ozone,and the former was better than the latter.On-line ozone can mitigate membrane fouling effectively and ozone backwashing slightly influenced on membrane fouling.The above results showed that combination of ozone and membrane can improve water quality and ozone can mitigate membrane fouling,which has a good prospect.