By Christof Kundel, Segment Manager Water Treatment, Bürkert Fluid Control Systems
Reverse osmosis systems play a central part in water treatment. In industrial applications, for example, reverse osmosis is used for purifying process water, producing drinking water and desalinizing seawater or for producing ultra pure or pharmaceutical water. In addition to these processes, which aim at reducing the concentration of the substances dissolved in the water, the beverage industry also uses reverse osmosis systems for increasing concentrations, e.g. in the manufacture of fruit juice concentrates or for concentrating the must in wine production.
Osmosis, a central active principle in nature, enables the regulation of water in cells and plants. If two fluids with different concentrations of dissolved particles are separated by a semi-permeable membrane, the difference in concentration is equalized by the physical process of diffusion until the concentration of the dissolved molecules is the same on both sides. Since the membrane allows only the solvent, generally water, but not the dissolved substances to pass, the osmotic pressure causes the solvent to move in the direction of the higher concentration of dissolved particles through the semi-permeable membrane.