ABSTRACT
This chapter discusses details of membrane processes such as microfiltration (MF), nanofiltration (NF), ultrafiltration (UF), reverse osmosis (RO) and forward osmosis (FO) which are currently most popularly used for water treatment areas like the desalination of brackish water and seawater. In recent decades, membrane-based separation processes have been adopted for industrial wastewater treatment with reasonable success. Polymer-based membranes are mostly used-membrane material but because polymers such as polysulfone, polyamide, polyvinylidienfluoride and polyethersulfone are hydrophobic, polymeric membranes are prone to fouling. This leads to the blockage of membrane pores and decreases membrane performance, it also increases operation costs by requiring extra cleaning processes. There are factors causing membrane fouling, such as the deposition of inorganic components onto the surface membrane/solute, absorption pore blocking, microorganisms and feed solute constituents. This results in either reversible or irreversible membrane fouling. Reversible fouling is formed by the attachment of particles to the membrane surface; irreversible fouling occurs when particles strongly attach to the membrane surface and cannot be removed by physical cleaning. When there is formation of a strong matrix of the fouled layer with the solute during a continuous filtration process this will turn reversible fouling into an irreversible fouling layer.
