Membrane filtration utilizes materials produce via casting and/or extrusion process. It is a type of physical filtration process where a contaminated fluid is passed through a special pore-sized membrane to separate microorganisms and suspended particles from process liquid. It is commonly used in conjunction with various other separation processes such as ultrafiltration and reverse osmosis to provide a product stream which is free of undesired contaminants. Membrane filters are typically used as the final filter in the process. Membranes are thinner than depth media pre-filter materials.