한외여과(UF) pilot plant를 이용한 낙동강원수의 처리

Abstract

This study focuses on the removal efficiency of dissolved and particulate matters with applying pretreatments, such as ozone-coagulation performance and ozone-coagulation-Roughing filter(Gravity Flow Fiber Filter) performance to UF membrane separation process. Also, it signifies the changes of permeate flux and fouling of membrane with pretreatment, thus suggests the appropriation of ozone-coagulation performance and ozone-coagulation-Roughing filter performance as the membrane filtration pretreatment process. After applying pre ozone-coagulation settling and pre ozone-coagulation-Roughing filter to hollow fiber UF as the pretreatment performance in 4 months, the result shows that the turbidity range of feed water is from 0.3245 NTU to 22.22 NTU, and that the average turbidity is 1.0 NTU in the beginning of the operation. However, the turbidity of the feed hits high level from 56 days to 79 days approximately after the initial operation. This is because of typhoon and heavy rainfall which become the cause of the temporary destabilization in settling basin in water treatment plant. Nevertheless, the quality of treated water always remains less than 0.1 NTU, much lower than the 0.5 NTU, the drinking water standard, and the average is less than 0.05 NTU in 4 months. The permeate fluxes are 148 LMH(L/㎥·hr at 20℃) and 149LMH(L/㎥·hr at 20℃). This result indicates that no matter how the quality of raw water differs, the permeate flux is not affected if the quality of membrane feed water fulfills a certain level with the pretreatment of coagulation-settlement and roughing filter. In the case of pre ozone-coagulation settling and pre ozone-coagulation-Roughing filter applied to hollow fiber UF membrane as the pretreatment process, KMnO4 and TPC of final treated water are 70.36 % and 99.9 % and 73.66 % and 99.91 %, the high removal efficiency. In the case of Al, Fe, and Mn, which can not be removed by membrane, the values with applying pre ozone-coagulation settling as the pretreatment procedure are 97.51 %, 100 %, and 60.27 %, and those with pre ozone-coagulation-Roughing filter are 90.67 %, 100 %, and 100 %, also the high remove efficiency. Therefore, the application of pre ozone-coagulation settling operation and pre ozone-coagulation-Roughing filter operation as the pretreatment method can be highly efficient to increase permeate flux and remove particulate matter and inorganic matter in practice plant.