Membrane filtration

Membranes, according to pore size, are divided into four groups: micro filtration; ultra filtration, nano filtration, reverse osmosis. They are different from each other the size of the molecules (impurities) retained. The membrane type is selected according to which pollutants predominate in the water: - RO - Reverse osmosis is one of the most advanced filtration technologies for deep desalination of water. This method uses semiconducting membranes, with a pore size of about 0.1 nanometers. Exposed to high pressure, water molecules and some solutes (less than membrane pore size) penetrates the membrane and other impurities are present detained.

The purified water is so pure that it can be stored when added to a glass polluted. Reverse osmosis water is the most widely used industry, to prevent corrosion and salt deposits in power plant turbines, boilers and pipes. Also, this technology can be used for seawater desalination. Sometimes, reverse osmosis is used to purify liquids that contain water an undesirable substance such as for the purification of ethanol. - Nanofiltration - is a relatively new filtration method used for sparingly dissolved for the softening of water containing substances such as surface water; and removal of disinfectants and other organic matter. Nanofiltration membrane pore size of 1 to 10 nanometers, less than microfiltration and ultrafiltration, but only higher than the pair of reverse osmosis membranes. Historically, nanofiltration and other membrane technologies have only been used separation of molecules in aqueous systems, usually water softening, separating "solid" Ca2 + and Mg2 + ions. Recently, nanofiltration has been increasing more commonly used in other industries such as dairy or juice production. Compared to reverse osmosis, nanofiltration is found to be lower energy consumption, but this method does not trap monovalent ions. - Ultrafiltration is a membrane filtration method in which, under pressure, the materials are separated through a semiconducting membrane. Particulate matter and large molecular weight substances are retained in the so-called concentrate, and water and low molecular weight substances penetrate through the membrane into filtrate. In industry, this separation process is most commonly used for concentration macromolecular (10 ^ 3 - 10 ^ 6 Da) solutions, especially protein solutions. This one technology is used for blood dialysis. Ultrafiltration can be used for solids particles and macromolecules from surface water, thus obtained drinkable water. Pathogen removal efficiency is 90 - 100%. In many cases microfiltration is used for pre - treatment of water before supplying it to reverse osmosis devices.

Pulp and paper industry
Pharmaceutical industry
Food industry
Oil industry
Textile industry
Municipal water supply
Chemical industry
Electric supply
Metallurgic industry
Electronics industry
Fertilizer industry
Glass-making industry
Agriculture industry
Fish farms
Plastics industry
Rubber industry
Wood industry
Cosmetics industry
Meat processing industry
Furniture industry
Dyestuffs industry
Dairy industry
Flow rate, m3/h 0.1 – 200
Inlet water TOC < 100 mgC/L
TOC removal efficiency, % 56 – 99 %
Micropollutants, phthalates removal efficiency, % 88 – 99 %
Disinfection efficiency >5 Log reduction
Color removal, % <1 NTU
Metal removal, % 74 – 97 %