School of Engineering, University of Guelph, 50 Stone Rd., Guelph, Ontario, Canada.
Water Environ Res. 2011 Jun;83(6):515-26. doi: 10.2175/106143010x12851009156529.
A tertiary membrane filtration (TMF) pilot operating on secondary effluent and a membrane bioreactor (MBR) were setup in a side-by-side study as pretreatments for two identical reverse osmosis pilot systems. The water quality of the permeate from both low-pressure membrane pretreatment systems and the fouling rate of the reverse osmosis systems were compared to assess the capabilities of the two low-pressure membrane pretreatments to prevent organic fouling of the reverse osmosis systems. Both pretreatment pilots were setup using typical operating conditions (i.e., solids retention time and mixed-liquor suspended solids). A consistent difference in water quality and reverse osmosis performance was demonstrated during the 12-month study. The MBR permeate consistently had significantly lower total organic carbon (TOC) and chemical oxygen demand concentrations, but higher color and specific UV absorbance compared with the permeate from the TMF pretreatment. The pretreatment with the MBR gave an average reverse osmosis fouling rate over the entire study (0.27 Lmh/bar.month) that was less than half of the value found for the reverse osmosis with TMF pretreatment (0.60 Lmh/bar.month). A correlation of reverse osmosis feed TOC concentration with average reverse osmosis fouling rate also was established, independent of the pretreatment method used. Results from a cleaning analysis, energy dispersive spectroscopy, and fourier transformed infrared reflectometry confirmed that the foulants were primarily organic in nature. It is concluded that, for this type of application and setup, MBR systems present an advantage over tertiary membrane polishing of secondary effluent for reverse osmosis pretreatment.
采用侧流方式并列运行三级膜过滤（TMF）中试装置和膜生物反应器（MBR）作为两个相同反渗透中试装置的预处理工艺，对比分析了两种低压膜预处理系统的产水水质和反渗透系统的污堵速率，以评估两种低压膜预处理工艺防止反渗透系统有机污堵的能力。两个预处理中试装置均采用典型运行条件（即固体停留时间和混合液悬浮固体浓度）进行设置。在 12 个月的研究期间，展示了水质和反渗透性能始终存在明显差异。MBR 产水的总有机碳（TOC）和化学需氧量（COD）浓度始终明显较低，但颜色和特定紫外吸光度（SUVA）较高，而 TMF 预处理的产水则相反。整个研究期间，MBR 预处理的反渗透污堵速率（平均 0.27 Lmh/bar·month）均小于 TMF 预处理的反渗透污堵速率（0.60 Lmh/bar·month）的一半。建立了反渗透给水中 TOC 浓度与平均反渗透污堵速率之间的相关性，与预处理方法无关。清洗分析、能量色散光谱和傅里叶变换红外反射光谱的结果证实，污染物主要为有机物质。因此，对于这种应用和设置，MBR 系统在反渗透预处理方面优于二级出水的三级膜抛光。
