DOI 10.35776/MNP.2019.09.02
UDC 628.16:62-278
Pervov A. G., Andrianov A. P.
The mechanisms of action of inhibitors in the process of calcium carbonate precipitate formation in reverse osmosis apparatus
Summary
Knowledge of the mechanism of precipitation of slightly-soluble salts on reverse osmosis membranes is extremely important while choosing measures to prevent it and reduce the consumption of concentrate. The conducted studies provided for enunciating a fresh approach to the mechanism of crystalline deposit formation and the role of inhibitors in preventing this process. The development of the experimental technique is based on the idea that the first crystallization phase — crystal nucleation is homogeneous, that is, occurs in stagnant zones in the concentrate volume at high oversaturation with calcium carbonate. Upon the formation the crystals are removed from the stagnant zones and settled on the membrane surface like other suspended particles present in the treated water. The results of studying the adsorption of polymer inhibitor molecules on the crystal surface during nucleation and crystalline growth on the membrane are presented. The experimentally obtained dependences of the rate of adsorption of inhibitors on the dose of inhibitors, the rate of formation of calcium carbonate, the rate of nucleation, and on the total surface of the germinal crystals are given. The study of micrographs of crystals showed the dependence of the size and number of crystals on the oversaturation value in the stagnant zone during nucleation as well as on the effectiveness of the inhibitor. A method is presented that allows determining the concentration of dissolved salts in the stagnant zones of the membrane apparatus and the oversaturation values corresponding to the onset of the crystallization process eliminating the addition and use of various inhibitors.
Key words
calcium carbonate , reverse osmosis , inhibitor , mechanism of precipitation on membranes , stagnant zones , nucleation rate , crystal growth rate , adsorption of inhibitor
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UDC 628.164
AHMEDOV G. Ya.
Removing carbonate deposits from geothermal heating and hot water supply systems
Summary
The method of removing calcium carbonate deposits from geothermal heating and hot water supply systems is considered. The results of experimental studies of dissolving calcium carbonate deposits in geothermal water in heat-exchange equipment by increasing carbon dioxide partial pressure are presented. On the basis of the conducted experiments a method and a flow scheme of dissolving calcium carbonate deposits that provide for elimination of heat loss with geothermal water used for treatment are suggested.
Key words
geothermal water , calcium carbonate , hot water supply , carbon dioxide , heat exchanger , acidity
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UDC 541.183:697.932.6.001.2
AHMEDOV G. Ya.
Enhancement of Efficiency of the Use of Geothermal Water for Hot Water Supply
Summary
Results of the study of the fractional composition of sand coming by with geothermal water from Apsheron, Karagan and Chokrak aquifers, and also its influence on kinetics of the precipitation of the solid phase of calcium carbonate from of geothermal water solutions are presented. A design scheme of effective use of geothermal water for hot water supply and heating is resulted.
Key words:
suspended substances , water supply , geothermal water , sand , water treatment , salt precipitation , calcium carbonate
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DOI 10.35776/VST.2022.02.05
UDC 628.32:22.765
Semin M. M., Tokarev Nikolai, Iavtushenko Marina, Lobanov Fedor, Chukalina Tat’iana, Plekhanov A. V.
Use of a chemical regulator at the wastewater treatment facilities operated by MUE Vodokanal of Podolsk
Summary
Possible use of natural minerals based on calcium carbonate (monocalcite) to correct pH (carbonate-bicarbonate equilibrium) in order to improve the treatment effect of activated sludge bacteria in the aeration tank and the sedimentation properties of activated sludge in the secondary settling tank is considered. The sedimentation properties of activated sludge are corrected because of the interaction between functional oxygen-bearing substrata of activated sludge flocculation bacteria and calcium ions. As a result, firm, rapidly settling flocs are formed and, consequently, the value of the sludge index decreases compared to the technological line and settling line operating in the regular mode. It is recommended to use a chemical regulator to normalize the operation of the aeration tank in winter (possible bioflotation), spring and autumn periods at high hydraulic loads.
Key words
calcium carbonate , sludge index , aeration tank , secondary settling tank , activated sludge , bioflotation
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DOI 10.35776/MNP.2020.01.01
UDC 628.16:62-278
Pervov A. G., Golovesov V. A., Spitsov D. V., Rudakova G. Ya.
Ways of reducing the operating costs of membrane units
for the preparation of drinking water from underground water sources
Summary
Experimental investigations have been conducted to determine the main process parameters of membrane units (filtrate yield, the rate of scaling on membrane surface). Basing on the results of the experimental studies the total costs of purification of underground water of various chemical composition were obtained. The studies were conducted on laboratory benches with the use of nanofiltration membranes with various selectivity rates. The consumption of service chemicals and operational costs for the equipment were calculated by the software designed earlier by the authors for determining the process parameters of membrane units. While designing membrane units, nanofiltration membranes with low values of selectivity, power consumption and expenditures for chemicals are preferred. The dependencies of the calcium carbonate scaling rates on membrane types and the multiplicity of volumetric concentration of source water were obtained. A comparison of costs shows that the use of membranes even for cases of water deferrization is more economical than the known traditional technologies.
Key words
calcium carbonate , ground water , concentrate , reverse osmosis , nanofiltration , water softening , scaling on membranes , deposits of slow-soluble salts in water , scaling inhibitors , scaling rate
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UDC 628.168.3:662.997
AHMEDOV G. Ya.
Stabilization Treatment of Geothermal Water
Summary
Stabilization treatment of geothermal water with the help of degasification and with the use of a crystalline initiator are considered. The experience of operation of geothermal equipment in the case of disturbance of carbonate-calcium equilibrium in water is presented. Degasification of geothermal water treated preliminary for carbon dioxide up to the equilibrium value makes it possible to speed up crystallization of calcium carbonate in the contact medium. It is proved that the more is the drop of pressure in a crystallizer the more is the concentration of a suspension being generated. The speed of separation of the solid phase of calcium carbonate from the geothermal water solution is proportional to the component of the pressure drop in the crystallizer from equilibrium to the final value.
Key words:
suspended substances , geothermal water , salt precipitation , calcium carbonate , degasification , softening
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