Third, high probability of “poisoning” of ion exchangers in organic compounds, dissolved in water and, consequently, reducing the effectiveness of the installation. In addition, the non-polar organic compounds are practically not retained on columns. As a result, they fall into the boilers and pipes, causing corrosion of equipment. In this regard, looks more promising application of the membrane and combined technologies such as reverse osmosis. Although that this method is quite expensive at the stage of initial investments, it is shown that at high oxidation of source water or salt content above 300 mg / L of reverse osmosis plant operation becomes more cost-effective than ion exchange (data VTI). Absolute advantage of reverse osmosis can be considered the possibility of full comprehensive cleaning of all types of pollution, no need for regeneration resins and as a consequence, the absence of large quantities of hazardous waste, compactness and ease of maintenance. In general, membrane filtration – the process of separating substances on a semipermeable membrane.
Their special feature is the ability to skip the solvent molecules, delaying the solute molecules. Currently, for manufacturing such membranes using a variety of modern materials, for example – and difluoride polivinildiena polysulfone. The most widely used in industry uses reverse osmosis as a driving force external (by the pump pressure). Different end goals are selected different options for layout of membranes and pumps, and on the reliability and efficiency of the latter depends on the functioning of the entire system. Generally, the membrane filtration units typically have multiple kinds of pumps. This increase (to increase pressure on logon).
They are designed to maintain constant pressure (0,5-6 Bar) in line prefiltration. To create a back pressure in the membrane used blower assemblies, and for water distribution to consumers apply switchgear. Selection of pumps is complex and is determined by other equipment that is used for immediate treatment, for example – the type of reverse osmosis membranes, which are selected determined by the composition of source water. In this regard, today the most widely ready (block) reverse osmosis modules. For example, such modules based on the materials and equipment of the leading manufacturers produce a Russian company and lenro ekodar. As a rule, special attention in the selection of pumps on the quality and material performance, as characteristic of the pumping equipment for membrane technologies treatment is the need to create large pressures to maintain flow through the membrane. High demands are made and corrosion-proof pumps, especially for handling concentrate. For these reasons, selection of pumping equipment is recommended to give preference to stainless steel (chromium content of at least 12%) or titanium. In addition to corrosion resistance, these materials, due to the oxide film on the surface of parts successfully withstand very high flow velocities, without undergoing erosion. It must be noted that in this case is very important and the quality (reduction of roughness) surface. These requirements are met, for example, multistage centrifugal pumps grundfos series crn, which are collected in Russia. Note that if the scheme provided for flushing the membrane with special acidic solutions, the application of pumps of the modern composite materials. Today we can confidently assert that the use of modern technologies and equipment, in particular – pumps, factories, of course, leads to the optimization of production and reduce costs and, hence, lowering the cost of energy produced. Moreover, the application of this technique reduces the environmental burden on the environment, that under current conditions is also important.