| Summary: | 碩士 === 國立成功大學 === 環境工程學系 === 88 === The research studied the application of nanofiltration (NF) membrane on advanced pretreatment of Feng-San city water with a Single Element Bench-Scale Test system (SEBST). The SEBST system utilized a single membrane element to investigate the effects of various operation pressures & recoveries on NF process. The study also evaluated the effects of different membrane materials as well as various pretreatments, such as GAC adsorption、with/and biofilter, and sodium sulfite addition, on NF fouling control.
The cleaning frequencies of NF 70 were 19 days & 9 ~ 12 days when the SEBST was operated with recovery of 15 % & 75 % respectively. The effect of sodium sulfite or antiscalant addition on cleaning frequency was minor. However, GAC adsorption & biofilter process extended cleaning frequency to 20 days as a results of decreased biofouling. When the hydrophilic LFCI RO membrane was used, the cleaning frequency reached 30 days under 94 psi operation pressure and 75 % recovery.
NF process removed 80% of hardness and 70% of chloride when the system was operated under 85 psi operation pressure and 75 % recovery. Both removal rates of hardness and chloride increased with increasing applied pressure, but decreased with increasing recovery. Rejection of hardness and chloride removal reached 90 % when LFCI RO was used, but with higher power consumption.
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