This study investigates the direct ultrafiltration process of municipal wastewater (MWW) at pilot scale. Short-term trials were conducted with two membrane modules to assess the fouling mechanisms using different physical cleaning methods: gas sparging (hydraulic cleaning) and rotation (mechanical cleaning). This work demonstrates that membrane rotation effectively erodes and re-disperses external fouling during the backwashing stages. Consequently, shear stress generated by the rotational movement enables the operation with permeate fluxes ranging between 24 and 30 L/hm², above the threshold flux value (22–24 L/hm²), while maintaining fouling rates (r_f) below 10 Pa/s. In contrast, r_f values increases up to 12.4–17.8 Pa/s when gas sparging is employed. Furthermore, the feasibility of up-concentrating municipal wastewater up to 12 times while operating with a net permeate flux of 20 L/hm² is demonstrated through a long-term trial. The increase in suspended solids concentration (TSS = 5750 mg/L and VSS = 4750 mg/L) favours the rapid formation of a reversible cake on the membrane surface during filtration, at moderate transmembrane pressures (26 cmHg). These operating conditions avoid cake layer compression and protect the inner surface of the membrane module from severe internal residual fouling with an energy consumption of 0.027 kWh/m³.

本研究以中试规模研究了城市废水 ( MWW ) 的直接超滤工艺。使用两个膜组件进行了短期试验，以评估使用不同物理清洁方法的结垢机制：气体喷射（液压清洁）和旋转（机械清洁）。这项工作表明，膜旋转在反冲洗阶段有效地侵蚀和重新分散外部污垢。^{因此，旋转运动产生的剪切应力使得渗透通量在 24 至 30 L/hm 2}之间运行，高于阈值通量值 (22–24 L/hm ² )，同时保持结垢率 ( r _f ) 低于 10帕/秒。相比之下，当采用气体喷射时，r _{f值增加至 12.4–17.8 Pa/s。}此外，通过长期试验证明了在净渗透通量为20 L/hm ²的情况下将城市废水浓缩至12倍的可行性。在中等跨膜压力 (26 cmHg) 下，悬浮固体浓度（ TSS  = 5750 mg/L 和VSS = 4750 mg/L）的增加 有利于过滤过程中在膜表面快速形成可逆滤饼。这些操作条件避免了滤饼层压缩，并保护膜组件的内表面免受严重的内部残留污垢的影响，能耗为0.027 kWh/m ³。