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517 1 At present, existing water treatment plants (WTPs) are being subjected to wide scale retrofitting, and new ones are being constructed in order to replace old sys tems that have worked out their service life and to sup port the operation of newly commissioned power installations. Works on retrofitting and newly con structed WTPs have to be carried out in increasingly more frequent occasions at combined cycle power plants (CCPs), the quality of makeup water for which must meet the most stringent requirements. These requirements are specified by equipment manufactur ers and may differ to some extent from one installation to another:Ion exchange is the main method that is presently used for demineralization of water at the majority of cogeneration stations (CSs), district power stations (DPSs), and nuclear power stations (NPSs) [1,2]. The use of such technology makes it possible to produce 1 The authors consciously put aside matters concerned with tech nical and economic substantiation of using an integrated mem brane system as a method for preparing demineralized water. The question of selecting a process circuit is in itself extremely interesting and important, and the authors are going to dedicate a separate work to it.Electrical conductivity, μS/cm 0.1-0.2 Concentration of, μg/dm 3 sodium 3.0-10.0 silicic acid (by SiO 2 ) 0.1-0.2 chlorides 3.0 total organic carbon 100-300 sulfates ( ) 3 Hardness, μg equiv/dm 3 5 2 4 − SO deeply demineralized water up to ultrapure state approaching in quality the theoretical limit equal to 18.2 MΩ cm. Subjecting water to deep final treatment using a mixed bed of ion exchange resins makes it pos sible to remove even the ions of weak electrolytes such as СО 2 and SiO 2 to a level of a few micrograms per cubic decimeter and the ions of strong electrolytes, to a level of a few hundredths of microgram per cubic decimeter.The number of filters operating in parallel is as a rule no less than three, one of which is always kept in a cold standby mode or is taken out for repair. Possible deviations from the normal operating mode of individ ual filters can always be compensated for by using sub sequent treatment stages having considerable margins in throughput capacity and efficiency.All drawbacks of this technology are connected with the need to use a large number of concentrated alkali and acid for restoring the exchange capacity of ion exchange resins. This, in turn, generates the need to set up a rather complex reagent facility and an efflu ent neutralization system. In addition, these systems produce high salinity wastes, the discharges of which must comply with certain limitations. It should be noted that the consumption of reagents is as a rule a factor of 2 to 3 higher than their stoichiometric levels, and the amount of discharged salts increases accord ingly. In the final analysis, all these factors entail high capital and operational costs.In view of unpredictable selectivity of ion exchange materials with respect to organic impurities, the content of total organic carbon i...

The process diagram of a water treatment plant constructed on the basis of integrated membrane technologies with the use of two stage reverse osmosis for the PGU 410 power unit at the Krasnodar cogen eration station is presented.