This module covers foundational concepts that are important for understanding the basic principles of membrane technology and its various applications. The three main themes of the module are (1) the properties and working principles of the membrane separation process, (2) the strengths and capabilities of membrane technologies and (3) the various applications. The scope of the module includes the membrane materials and their properties, preparation and characterisation of synthetic membranes and transport phenomena in membranes, as well as polarisation phenomena and fouling. The module also covers the different types of membrane processes and their applications including pressure driven, concentration, thermally driven, membrane contactors, electrically driven, and membrane bioreactors.