研究結果顯示，污水廠進、放流水質數據，經計算藍氏飽和指數(Langelier Saturation Index, LSI)及萊氏穩定指數(Ryznar Stability Index, RSI)結果，水質較偏向腐蝕，具不易結垢之特性。透膜壓力(Transmembrane pressure，TMP)與薄膜滲透性關係呈現反比，TMP愈高，滲透性愈低。不同曝氣強度影響掃流速度，曝氣強度控制在40 LPM，可維持較佳滲透性。污泥濃度若控制在4,000~8,000mg/L範圍，對MBR操作較佳。薄膜產水通量控制在2.15 LPM，其滲透性明顯優於2.7 LPM及3.2 LPM，產水通量增加，TMP上升速度亦增快，會加速薄膜積垢速率。維護性藥洗以0.2%鹽酸、進藥2分鐘、進水8分鐘反覆3次循環之效果為佳；恢復性藥洗效果原則以16小時為佳，較能去除/延緩薄膜積垢。此外考量竹科事業製程變動性，須定期進行水質檢測分析，以掌握水質特性。依據薄膜耐酸鹼程度，選擇適合竹科水質特性之薄膜進行操作，並建議操作一段時間後，定期檢視薄膜外觀是否有斷絲或纏繞現象，確保產水水質。
In order to conform with the latest effluent ammonia nitrogen control limitation, Hsinchu Science park sewage treatment plant uses Membrane Bioreactor (MBR) as the key treatment process to enhance the function. The fouling resulted from water characteristics may influence the service life of membrane, so this study aims at the wastewater (sewage) of Hsinchu park sewage treatment plant, and discusses the potential factors in membrane fouling. The specific research content includes the quality of influent and effluent of the sewage treatment plant in last three years, analysis of wastewater characteristics; the model plant with the same process as the actual plant is used for experiment, the parameters are adjusted to understand the influence of different operation factors on membrane fouling.
The findings show that the influent and effluent quality data of sewage plant are used to calculate Langelier Saturation Index (LSI) and Ryznar Stability Index (RSI), the results show that the water is relatively corrosive and unlikely to scale. The transmembrane pressure (TMP) is inversely proportional to the membrane permeability, the higher the TMP is, the lower is the permeability. Different aeration rates influence the crossflow velocity, the permeability is better if the aeration rate is controlled at 40 LPM. If the sludge concentration is controlled at 4,000~8,000mg/L, it is favorable for MBR operation. When the membrane permeate flux is controlled at 2.15 LPM, the permeability is obviously better than 2.7 LPM and 3.2 LPM. The TMP increases faster as the permeate flux increases, the membrane fouling is accelerated. Three cycles of maintenance cleaning procedure with 0.2% HCl, 2 minutes′ agent feed and 8 minutes′ water feed have good effect; 16 hours′ maintenance cleaning procedure is preferred, which is likely to remove/retard membrane fouling. In addition, considering Hsinchu Science Park undertaking process variability, the water quality must be tested periodically, so as to master the water characteristics. According to the acid and alkali resistance of membrane, the membrane suitable for Hsinchu Science Park water characteristics is selected for operation, and it is suggested to periodically check whether the membrane appearance has filament break or wrapping after a period of operation, so as to guarantee the treated water quality.
Keywords: membrane bioreactor (MBR); fouling; membrane permeability; transmembrane pressure (TMP)