**2. Challenges**

Membrane processes such as MF, NF, UF and RO are currently used for water reuse, brackish water and seawater [17]. Polymer based membranes are mostly used membrane material but because polymers such as polysulfone and polyethersulfone, are hydrophobic [18], polymeric membranes are prone to fouling [19]. This leads to blockage of membrane pores and decrease membrane performance [20], also increases operation cost by demanding extra cleaning process. There are factors causing membrane fouling, such as deposition of inorganic components onto the surface membrane/solute absorption pore blocking, microorganism and feed chemistry [21]. This results to either reversible or irreversible membrane fouling [22]. Reversible fouling formed by attachment of particles on the membrane surface, irreversible which occurs when particles strongly attach the membrane surface and cannot be removed by physical cleaning. When there is a formation of strong matrix of the fouled layer with the solute during continuous filtration process will turn reversible fouling to irreversible fouling layer [23].
