The membranes is basically made up of 3 thin layers of Polyamide layer at the top, Polysulfone layer at the middle and finally polyester layer at the bottom. Polyamide layer is 0.2 µm, polysulfone layer is 40 µm and polyester layer is 120 µm. The three layer configuration gives the preferred properties of high elimination of undesired materials (like salts), high filtration rate, and good mechanical strength. Depending on the pore size, membranes can be classified as Micro Filtration (MF), Ultra Filtration (UF), Nano Filtration (NF) and reverse osmosis (RO) membranes. Membranes can also be of various thicknesses, with homogeneous or heterogeneous structure. Membranes can be neutral or charged, and particle transport can be active or passive. The concluding can be facilitated by pressure, concentration, chemical or electrical gradients of the membranes process.