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

膜技术已广泛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、出水水质上级、不受原水水质波动影响、运行稳定等优点，特别适合寒冷地区饮用水生产。然而，膜技术在寒冷地区的应用存在重大挑战。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，以克服冷水温度引起的问题，并提高膜性能，工艺和化学清洗效率，并最大限度地延长膜寿命。本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，减少清洗中的化学品使用和能源消耗，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、渗透性恢复和膜结构变化的动力学的影响有基本的了解; 2.）研究了膜结构在冷水运行-温水清洗循环过程中的动态变化，模拟了膜孔径对冷热水循环的热响应。3.测试预混凝对膜污染的影响; 4.）优化化学清洗工艺，5.）发展对膜纤维断裂的机制和减少低温下膜断裂的策略的基本理解;以及6.）表征污垢（有机和无机污垢）的性质和化学清洗效率。最终目标是开发操作和化学清洗策略，以减轻冷水温度对膜性能和结构的负面影响，以减少化学和能源的使用，并最大限度地延长膜在寒冷地区的使用寿命。

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.