在我国，高压膜分离技术（纳滤和反渗透）广泛应用于城市污水回用。然而，膜生物污染成为限制其应用的瓶颈。在高压卷式膜元件中，进水隔网结构决定了流道中的水力条件，进而影响膜生物污染。但是，进水隔网结构、水力特性和膜生物污染之间的联系尚不明晰。本研究结合计算流体力学模拟、水力试验和膜污染试验，探究网格单元结构、网丝变径结构以及网丝微观结构对流道内水力特性和膜生物污染的影响，解析流道中污染的时空分布特征，揭示隔网结构、水力特性和膜生物污染之间的联系，旨在为进水隔网的设计和优化及膜污染控制提供理论依据。通过动态膜生物污染试验，发现污染初期，膜表面剪切力小的区域生物污染较重；而污染中后期，生物膜开始淤积在网丝与膜面间隙，造成过水通道堵塞、流场均匀性下降，加剧了膜污染速率，使流道压降差升高34–48%。此外，验证了短周期加速污染试验可以替代长周期污染试验，用于比较不同进水隔网的抗污染性能和预测流道压降差的变化。
In China, high-pressure driven membrane technologies (nanofiltration and reverse osmosis) have been universally applied in municipal wastewater treatment and reclamation. Nevertheless, membrane biofouling is the bottleneck of its wide applications. In high-pressure spiral wound membrane elements, feed spacer determines the hydraulic conditions in the feed channel, which influences the occurrence of membrane biofouling. However, the relationship among feed spacer geometry, hydrodynamics and membrane biofouling remains unclear. This study investigates the impacts of spacer mesh structures, non-uniform filament features and microscopic filament characteristics on the hydrodynamics and membrane biofouling, analyzes the spatial distribution and temporal evolution of biofouling in the feed channel, and uncovers the connections between feed spacer geometry, hydrodynamics and membrane biofouling. This study is expected to provide theoretical foundation for the design and optimization of feed spacer as well as better biofouling control strategies. The results of long-term dynamic biofouling experiments indicate in the incipient stage, the regions with low shear stress were severely fouled. In the late stage, biofilm accumulated in the interspace between spacer filaments and membrane, which blocked the flow channel, decreased the uniformity of flow field, and thus facilitated biofouling rate and increased the feed channel pressure (FCP) drop by 34–48%. In addition, short-term accelerated biofouling experiment was proven to be an applicable substitute for long-term biofouling experiment when comparing the anti-biofouling performances of feed spacer and when evaluating the impacts of biofouling on the FCP drop.
