Pressure-driven membrane processes, i.e., microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse-osmosis (RO), are globally recognized as an essential element in sustainable water management systems, thanks to their intrinsic advantages when compared to conventional processes, as well as to their versatility. Today, pressuredriven membrane processes are used for water treatment, purification, and reuse. Despite the successful development in recent decades of membrane filtration up to the industrial scale, huge interest in the optimization of membrane processes still exists. This has been realized so far through various approaches—for instance, the introduction of ultralow pressure or low fouling membranes, improving membrane retention and/or selectivity, increasing membrane life span, in addition to reducing energy consumption and the use of chemicals. In addition to advanced membrane materials and module design, the optimization of membrane processes or combining them with other treatment processes have increasingly become the focus of engineering researchers. The ultimate objective is commonly to further promote membrane process efficiency towards more sustainable, cost-effective, and environmental-friendly water treatment applications.