Strategies to Improve Membrane Performance of Drinking Water Productions in Cold Regions

膜技术已广泛应用于世界各地的饮用水生产，包括加拿大等寒冷地区。膜技术具有操作简单、占地面积小、水质优良、运行稳定等优点，特别适用于寒冷地区的饮用水生产。然而，膜技术在寒冷地区的应用面临着巨大的挑战。冷水温度对产水率、膜性能和结构变化有显著的负面影响。因此，应开发独特的操作和化学清洗策略，以克服冷水温度造成的问题，提高膜的性能、工艺和化学清洗效率，并最大限度地提高膜的寿命。这项研究的总体目标是开发操作和化学清洗策略，以优化膜性能，恢复膜结构损失，减少清洗过程中的化学品使用量和能耗，并最大限度地延长寒冷地区膜的使用寿命。具体目标包括：1.)对温度对化学清洗动力学、通透性恢复和膜结构变化的影响有一个基本的了解；研究了冷水运行-温水清洗循环下膜结构的动态变化，模拟了膜孔径对冷温水循环的热响应。3.测试预共混凝对膜污染的影响；优化化学清洗方案，5.)对膜纤维断裂的机理和在低温下减少膜断裂的策略有一个基本的了解；表征污垢的性质(有机和无机污垢)和化学清洗效率。最终目标是制定操作和化学清洗策略，以减少冷水温度对膜性能和结构的负面影响，减少化学和能源消耗，并在寒冷地区最大限度地延长膜的寿命。

Membrane technology has been widely used for drinking water production all over the world, including cold regions like Canada. Membrane technology is particularly suitable for drinking water production in cold regions, due to its advantages of operation simplicity, small footprint, superior water quality, and stable operation with regarding to the fluctuation of raw water quality. However, significant challenges exist for the application of membrane technology in cold regions. The cold water temperature has a significantly negative impact on the water productivity, membrane performance and structure change. Therefore, unique operational and chemical cleaning strategies should be developed to overcome the problems caused by cold water temperature and improve membrane performance, process and chemical cleaning efficiency, and maximize membrane lifespan. The overall goal of this study is to develop operational and chemical cleaning strategies to optimize membrane performance, recover membrane structure loss, and reduce chemical usage in cleaning and energy consumption, and maximize the lifespan of membranes in cold regions. Specific objectives include: 1.) develop a fundamental understanding of the effect of temperature on the kinetics of chemical cleaning, permeability recovery, and membrane structure changes; 2.) study the dynamic changes of membrane structure under cold water operation-warm water cleaning cycles and model the thermal response of membrane pore sizes to cold-warm water cycles. 3. test the impact of pre-co-agulation on membrane fouling; 4.) optimize chemical cleaning potocols, 5.) develop a fundamental understanding of the mechanisms of membrane fiber breakages and strategies to reduce membrane breakage in cold temperature; and 6.) characterize the nature of foulants (organic and inorganic fouling) and the chemical cleaning efficiency. The ultimate goal is to develop operational and chemical cleaning strategies to abate the negative impact of cold water temperature on membrane performance and structure to reduce chemical and energy usage, and maximize membrane lifespan in cold regions.