Effects Of Direct Ultrafiltration Process On Micro-Polluted Source Water Treatment And Membrane Fouling Control

The better water purification efficiency of the ultrafiltration process makes it have a very broad application prospect in the advanced treatment of drinking water.For the rural areas where the source water has micro-pollution characteristics,the intensive treatment or advanced treatment process of the conventional treatment process is cumbersome,complicated in operation,relatively high in management cost,and unsuitable for promotion in rural areas.In recent years,with the improvement of drinking water quality demand in rural areas,ultrafiltration technology has further application in rural areas due to its better water purification effect,higher integration level and lower operating cost.Development,which has an advantage in the promotion of ultrafiltration in rural areas,but the main obstacles to the promotion of integrated miniaturization ultrafiltration systems are complex backwashing systems,many unit control valves and membrane fouling.In this paper,in order to promote the problems in the application of drinking water ultrafiltration in rural areas,the integrated single-valve gravity backwash ultrafiltration device was formed by a single backwash valve with a high gravity gravity tank controlled by Li Guibai.The ultrafiltration device was compared and represented by the raw water of the Yellow River Reservoir.The direct test of the raw water from the Yellow River Reservoir was carried out to test the direct test.The ultrafiltration membrane selection,stable operating flux,membrane pollution control and operating cost were analyzed.The ultrafiltration process was applied to treat the application efficiency of the raw water from the Yellow River Reservoir,and the direct water filtration efficiency of the raw water from the Yellow River Reservoir was evaluated by the direct ultrafiltration process.The flat membrane ultrafiltration small test system was used to investigate the chemical intensification backwash caused by organic pollutants.Ultrafiltration membrane irreversible pollution control efficiency to solve the bottleneck of ultrafiltration process in rural areas.Taking the raw water of the Yellow River Reservoir as the water source,the operating conditions of the integrated single-valve gravity backwash ultrafiltration device and the immersion ultrafiltration device are first optimized according to the membrane fouling.The results show that when the single-valve gravity backwash ultrafiltration device is used to filter the raw water of the Yellow River Reservoir,the internal pressure type PVC alloy ultrafiltration membrane with low molecular weight cutoff is selected,and 10mg/L NaClO is added to the backwash water for chemical strengthening.Backwashing effectively extends the maintenance chemical cleaning cycle.For the immersion PVC composite membrane ultrafiltration system,the 10L/(m~2·h)flux operation can reduce the maintenance chemical cleaning frequency and prolong the service life of the ultrafiltration membrane.The direct effluent process to treat the effluent water quality of the raw water from the Yellow River Reservoir shows that the direct ultrafiltration process has good water purification efficiency,the effluent turbidity is lower than 0.1 NTU,the average removal rate is about 98%,and the removal rate of CODMn in the water of the Yellow River Reservoir is obtained.It is about 36%,and the removal rate of bacteria and algae is over 99%,which can ensure the biosafety of drinking water.The direct ultrafiltration process can ensure the stability of effluent water quality for the large fluctuation of raw water quality in summer.The effluent meets the drinking water.Health Standards(GB5749-2006)requirements.Membrane fouling caused by humic acid,sodium alginate and bovine serum albumin solution during chemically enhanced backwashing was studied using a flat membrane ultrafiltration system.The results show that with the increase of the filtration volume,membrane fouling is caused,causing a decrease in specific flux and an increase in membrane resistance.Adding NaClO to the backwashing water has a good removal effect on the membrane fouling caused by humic acid,and can convert some of its irreversible pollution into reversible pollution with backwashing.The membrane fouling caused by directly filtering the raw water of the Yellow River Reservoir is mainly irreversible pollution,and as the filtration cycle increases,the total pollution of the ultrafiltration membrane is also aggravated compared with the filtration of a single organic pollutant.The addition of NaClO in the backwashing water will increase the backwashing efficiency relatively,and the raw water composition is complex,but the humic acid in the organic pollutants of the raw water accounts for the main component.Therefore,as the concentration of NaClO increases,the membrane fouling caused by the raw water has a certain control effect.