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UDC 628.16(083.75)

Mazaev V. T., Shlepnina T. G.

Assessment of the Sanitary Hazard Degree of Silicon Compounds in Natural and Potable Water

Summary

The survey of literature on the role of silicon in the human body, its toxicokinetics is conducted; the critical analysis of scientific substantiation of hygienic standards of maximum concentration of silicon compounds in natural and potable water is made. The attention is paid to the absence of standards concerning the silicon content in water in the foreign standard specifications because of non-actuality of the problem. It is proposed to cancel the standard of limit content of silicon in the domestic normative base in connection with the absence of its proper reasonableness.

Key words

potable water , maximum permissible concentration , silicon , normative , hardness , salt-content

UDC 628.164-92:66.081.63
DOI 10.35776/VST.2023.05.01

Kasatochkin A. S., Larionov S. Iu., Kharitonov Nikolai, Shilov Mikhail, Savochkin Andrei, Riabchikov Boris

Purification of water with high permanent hardness and salinity

Summary

Chemical softening methods have been widely used in the practice of water treatment, primarily in the energetics and industry for softening, decarbonization and decoloration of water. In combination with reverse osmosis, they provide for preparing water of the required qualitative composition. In drinking water supply softening methods are used quite rarely due to a number of circumstances, such as the need to use various chemicals that are not typical for public water supply; generation of a large volume of sludge subject to subsequent processing, and, what is most important, resulting in highly alkaline water with pH of more than 10 unacceptable for drinking water. However, in case only but water sources with such a complex composition are available, then chemical methods have to be used. In Mediana-Filter Research and Production Company, JSC studies were carried out to obtain high-quality water from an underground source of uncharacteristic salt composition, with a high content of sulfates and low alkalinity, provided that the purification technology should generate minimum liquid waste. After testing several technology options in pilot plants, a scheme was proposed that met the requirements of the customer. It should be noted that underground water of the southern regions of the country has a partially similar salt composition, so the results of pilot tests can also be applied to obtain drinking water from similar sources.

Key words

reagent treatment , flow chart of treatment , reverse osmosis , desalination , hardness , pilot plant , sulphates , water , dynamic softening system , liming , sodium liming , soda softening , sludge blanket , dynamic softening system water conditioning

UDC 628.16.066.1:628.164-92
DOI 10.35776/VST.2023.08.01

Bobinkin V. V., Vukolov Oleg, Gizzatullin Artur, Kasatochkin A. S., Kostylev Evgenii, Larionov S. Iu., Oliunin Sergei, Panteleev Aleksei, Riabchikov Boris, Savochkin Andrei, Shilov Mikhail

Industrial horizontal intensified clarifier for water
softening/decarbonization by liming

Summary

Chemical softening methods have been widely used in the water treatment practice. As shown in the previous review, the chemistry of the process has remained unchanged over the past 100 years; however, the instrumentation of the process has changed. This equates to significantly increase the capacity and efficiency of the devices. Research work has been carried out on designing domestic intensified apparatus for softening/decarbonization of water by liming; and their introduction into industrial practice has started. Studies of the developed version of the multi-chamber horizontal clarifier with liming of Aquafloc type were carried out. The boundary parameters of the process of water liming with coagulation with iron salts were determined. It was established that the improved mixing, acceleration of chemical reactions and recirculation of carbonate sludge (seed) provide for the optimization of the sedimentation process to reduce the coagulant consumption and significantly improve the sludge characteristics. Essential advantages of the clarifier are as follows: smaller dimensions and metal consumption compared to classical clarifiers, as well as a short time to reach the operating mode. Thereby, an Aquafloc clarifier can be delivered to the site ready assembled, ready-to-use and with anti-corrosion protection that significantly reduces the time and cost of assembling at the facility. The concentration of dry matter in sludge reaches 8%. In comparison with the existing VTI-630 clarifiers, Aquafloc clarifier showed similar results in terms of chemical parameters and the best in terms of the concentration of suspended solids. In terms of water consumption for own needs, the clarifier turned out to be at the level of VTI apparatus that have a total blowdown volume of 2–4%.

Key words

coagulation , suspended layer , hardness , enhanced treatment , water , mixing , chemical water softening , liming , horizontal clarifier

UDC 628.16.066.1:628.164-92
DOI 10.35776/VST.2023.03.03

Savochkin Andrei, Kasatochkin A. S., Panteleev Aleksei, Riabchikov Boris, Larionov S. Iu., Gizzatullin Artur

Designing horizontal clarifiers and studying the efficiency of the water liming process

Summary

Chemical softening methods have been widely used in water treatment. As shown in the previous review, the chemistry of the process has remained unchanged for the past 100 years; however, the instrumentation has changed. This provides for increasing significantly the capacity of the devices and their efficiency. Mediana-Filter R&P JSC carried out research on the development of domestic intensified devices. The studies were carried out in a small-scale laboratory three-chambered horizontal clarifier with a lamellar settling tank and in a pilot clarifier with a variable chamber volume. The optimal procedure of introducing chemicals, the minimum and optimal residence time of water in the clarifier chambers have been determined. The achieved rate of the upward flow in the zone of clarification in the boundary conditions was 25 m/h. The data obtained was taken as a basis ground for designing industrial apparatuses.

Key words

suspended layer , hardness , water , mixing , chemical water softening , liming , horizontal clarifier

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UDC 628.16

Gandurina L. V., Kvitka L. A., Shakhgaldian M. K.

Reducing color of natural water with the use of organic coagulants

Summary

The results of studies of the effectiveness of reducing color of low-turbid natural water by filtration with the use of organic coagulants of domestic trademarks: VPK-402, Kaustamin-15 and Biopag are presented. It is shown that the decrease in color of natural waters with organic coagulants occurs mainly due to coagulation processes at low alkalinity close to zero, and chemical interactions of the polyanion of humic acids with the coagulant polycation with alkalinity more than 1.2 mmol-eq/l. It was determined that the optimal doses of organic coagulants increase with a decrease in molecular weight in the series VPK-402 < Kaustamine-15 < Biopag and an increase in alkalinity of the treated water; whereas with an increase in hardness – decrease. In the alkalinity range of 1.2–2 mmol-eq/l the specific consumption of coagulants VPK-402 and Kaustamin-15 increases from 0.04–0.06 to 0.12 mg per degree of initial color while low-molecular Biopag coagulant practically does not change and is 0.09 mg/degree. The dispersion of the formed particles of the suspension increases with a decrease in the hardness of the treated water, an increase in alkalinity and the concentration of low molecular weight fractions of humic acids in water being purified which is accompanied by an increase in color of the purified filtered water. It is shown that the standard decrease in water color below 20 degrees is achieved by removing coagulated particles with a size of more than 0.3 microns in the process of filtration.

Key words

turbidity , chromaticity , coagulation , natural water , filtration , hardness , alkalinity , organic coagulants

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UDC 628.16.066.1:628.164-92
DOI 10.35776/VST.2023.01.04

Riabchikov Boris, Panteleev Aleksei, Larionov S. Iu., Savochkin Andrei, Shilov Mikhail, Kasatochkin A. S.

Current state of the development of installations for water softening/decarbonization by liming (a review)

Summary

Chemical softening methods have been widely used in water treatment to reduce hardness and decarbonize water. The chemistry of the process has remained unchanged for the last 100 years, however, the instrumentation and some nuances of the technology are changing, i. e., the use of devices (lamellar blocks) for stabilizing flow and improving sludge settling, the use of flocculants and introduction of sludge formation centers (recirculation of activated sludge, microsand), etc. A separate method is the adoption of horizontal multi-chamber apparatus with mechanical mixing. This method provides for increasing significantly the capacity and efficiency of the apparatus. Modern ways of development of such apparatus and technologies in the Russian Federation and overseas are considered.

Key words

suspended layer , hardness , water , mixing , chemical water softening , liming , installations