纳滤膜处理受污染地下水的运行影响因素研究

Factors Affecting Operation of Nanofiltration Membrane Process Treating Polluted Groundwater

以预处理、纳滤组合工艺处理受污染地下水，分析了操作压力、运行时间、水温及预处理等因素对终端纳滤膜运行性能的影响。研究表明，以活性炭为预处理的纳滤膜通量衰减速率最小，说明由有机物造成的纳滤膜污染作用明显大于铁、锰及硬度等引起的无机污染；当膜进水操作压力由0．3MPa增至0．8MPa时，膜通量由8．7L／（m^2·h）线性增至19．1L／（m^2·h），而离子截留率、硬度及碱度去除率却呈线性降低；对高锰酸盐指数的去除率随运行时间的增加而明显下降，在80h内降幅达12．5％，而总硬度的去除率则随运行时间变化不明显；当水温在5～25℃变化时，随着温度的升高则膜通量增加，但对盐的截留率减小，对有机物的去除率没有显著影响，而对硬度的截留率在22℃以前变化不大，当温度〉22℃后会有较大的下降。

Polluted groundwater was treated by nanofihration membrane process combined with pretreatment. The critical factors affecting terminal nanofihration membrane operation, including operation pressure, run time, water temperature and pretreatment etc. were studied. Results show that the decreasing rate of membrane flux is least when activated carbon is used for pretreatment. Thus, membrane is polluted more by organic matter than by inorganic ones, such as iron, manganese and hardness. When the operation pressure of membrane influent is increased from 0.3 MPa to 0.8 MPa, membrane flux is linearly improved from 8.7 L/（ m^2 · h） to 19.1 L/（ m^2 · h）. At the same time, the rates of holding back ions, hardness and alkalinity removal decrease linearly. Permanganate index removal rate drops markedly with operation time increasing; the drop scope is 12.5% in 80 h, while the total hardness removal changes little. When the groundwater temperature is in the extent of 5 - 25℃, membrane flux increases and salt holding back rate decreases with temperature growth. Temperature has no distinct effect on organic matter removal. Hardness removal changes little when temperature is less than 22 ℃, while it decreases markedly when temperature is more than 22 ℃.