EFFECTIVE MEMBRANE PROCESS TO REMOVE HIGH CONTENT OF ALGAE AND ITS ASSOCIATED TASTE AND ODOR PROBLEM: A CASE STUDY, THE HAN RIVER IN KOREA

摘要

Most of the surface water sources in Korea are detected with high content of algae andprecursors of taste and odor. This becomes more severe during summer season, whichdetrimentally affects the intake water quality to water treatment facilities. When treating surfacewater with high concentration of algal species, conventional water treatment methods includingfiltration have a low removal efficiency of taste and odor, and often times resulted intodifficulties such as filter clogging, low settleability, the increased dosage of coagulants and usageof activated carbon, as well as a high chlorine usage. Algae is also a major contributor tomembrane fouling and a high trans-membrane pressure (TMP), challenging task to avoidpotential fouling. This study presents an effective case study that demonstrates successfulremoval of algae and compounds associated with taste and odor in an advanced process train:Coagulation/flocculation/sedimentation ==> pressurized microfiltration (MF) ==> granularactivated carbon (GAC). This paper presents results of one-year-study conducted at a drinkingwater plant in City of Incheon, Korea. The pilot size was 35,000 gal/d (135 m~3/d). The intakewater was from the Han River. The pressurized microfilter was a polyvinylidene difluoride(PVDF) membrane with 0.1 micron pore size. The flux was set at 38 gpd/ft~2 (1.5 m~3/m~2·d) with a90% recovery rate. The advanced treatment process has demonstrated a very effective method inreducing the algae content and its associated taste and odor problem, comparing to aconventional sand filter.