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UDC 628.17.001.4
Alekseeva L. P., Alekseev S. E., Korsa-Vavilova E. V., Shmelev A. Ia.
The use of ozone in surface water purification for public water supply of small communities
Summary
Two options of using ozone in purification of water from surface water supply sources with excess concentrations of organics in block-modular plants of small capacity are considered. Ozone effecting the changes in the basic water quality parameters is shown. The use of ozone in surface water purification extends the potential of the technologic process control under frequent seasonal fluctuations of the raw water quality, improves the quality of water after purification which is most important in the operation of small capacity plants. Besides, ozonation provides for reducing significantly the dosages of chemicals (coagulant and flocculant), and in some cases (during certain seasons) eliminating completely their use. The process studies carried out in a block-modular plant manufactured by «Moskosvskie Ozonatory» Company showed that the ozonation of the Volga River water for public water supply can be carried out using two process schemes: ozonation and sorption in carbon filters; or coagulation, ozonation and sorption. The parameters and conditions of using the ozonation, coagulation and sorption methods were specified; their efficiency at the minimum required chemical dosages was determined. It was stated that the use of ozone in block-modular plants for surface water purification provided for improving significantly the quality of drinking water regardless of the seasonal fluctuations in raw water quality; improving the integrity of the water supply system by all the parameters including microbiological ones. The effect of certain structural and technological solutions at the facilities on the water purification efficiency was noted.
Key words
potable water , ozonization , surface water source , coagulation , organic pollutants , block-modular plant
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DOI 10.35776/VST.2021.03.06
UDC 628.345
Alekseyev E. V.
The use of «coasorption» concept while describing the effect of coagulants on the wastewater aqua systems (for discussion)
Summary
The widespread use of chemical coagulation in purification of natural water and industrial wastewater is due, on the one hand, to the complex chemical composition and phase-disperse state of their aqua systems, and on the other hand, to the multifactorial effect of coagulants on them. The main mechanisms of interaction between coagulants and pollutants are considered through the example of industrial wastewater treatment containing organic substances (surfactants and synthetic dyes). The physicochemical term «coagulation» reflects only one of the mechanisms of the effect of coagulants on pollutants. The currently accepted process parameters «dose of coagulant» and «specific dose of coagulant» do not reflect the variety of interactions of pollutants with coagulant salts either, and are not linked to the result of coagulation. This makes it difficult to describe the collective effect of physicochemical processes while adding coagulants to the treated water and to quantify it. The solution to the problem is possible introducing the concept of «coasorption» that determines the multifactorial origin of the interaction of coagulants and pollutants in the processes of wastewater treatment by coagulation; and the process parameter «specific coasorption» that establishes a quantitative relationship between the concentrations of pollutants in raw wastewater and effluent with a dose of coagulant. The specific coasorption functions are graphically presented in the form of coasorption isotherms for two types of surfactants and synthetic dyes. Based on the results of the analysis of the features of the isotherms, it is shown that they reflect different mechanisms of interaction between coagulants and pollutants. The use of coasorption as a technological concept provides for identifying the mechanisms of interaction of pollutants with a coagulant and establishing the best conditions for the coagulation process. The functional description of the coasorption isotherms allows extrapolating the results of trial coagulation in a wide range of pollutant concentrations. The practical importance of specific coasorption isotherms provides for determining the dosages of chemicals during coagulation of water based on the initial concentration of pollutants and effluent standard.
Key words
wastewater , coagulation , sorption , coagulation , aqua system , heterocoagulation , adagulation , coasorption , specific coasorption
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UDC 628.16.8
Kichigin V. I., Strelkov A. K.
Study of underground water treatment technologies in the northern regions of Russia
Summary
The results of studies of possible use of the underground water treatment process scheme of one of the northern regions of Russia are presented. The versatile container plant includes: ozonators, electrical flotocoagulators, contacts clarifiers and rapid filters, sorption filters with various activated carbon media, membrane filter, UV-irradiation unit for water processing, chemical plant for feeding Aqua-Aurat™30 coagulant and Praestol flocculant to water. Raw water was described as low-turbid, colored, medium mineralized (mainly chloride-sulphatic-bicarbonate). The quality indicators of water surpassed the requirements of SanPiN in terms of color (72 degree platinum cobalt color scheme), turbidity (11.2 mg/dm3), flourides (2.2 mg/dm3), total iron (4.54 mg/dm3, including Fe2+ – 4.51 mg/dm3), manganese (0.11 mg/dm3). It was shown that water purification according to the scheme «ozonation-chemical filtration-sorption filter-UV-irradiation-membrane unit» provided not only for color and turbidity reduction but also for nearly hundred percent removal of manganese, fluorine and iron. This process scheme can be recommended for introduction at the water treatment plants.
Key words
ozonization , ground water , filtration , coagulation , polar zone , flocculation
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UDC 628.161:536.22
Fomina V. F.
Features of Coagulation of Low Turbid, Color Water of the Vychegda Under Conditions of Low Temperature
Summary
Results of the reagent treatment of low turbid and color water of the Vychegda for the purpose of selection of the efficient method of its clarification is presented. The process of coagulation is characterized by the formation of small, poorly settling flakes. Low temperatures of water require increasing the optimal doses of coagulant almost two times and the optimal doses of flocculant more than two times. It is shown, that the water discoloration up to 5–10 degrees and its maximal clarification are achieved in and around of optimal pH values. The empirical dependences of a coagulant’s dose on influent water color with due regard for its temperature are given. The efficiency of low temperature water treatment depends substantively on flocculation process, the duration of which multiplies several times during the periods of water's low temperatures. Under these circumstances the pressure flotation is the most reasonable and efficient method of clarification.
Key words
clarification , chromaticity , flocculation , coagulant , flocculant , coagulation , alkalizing reagent , water temperature , pressure flotation
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UDC 628.161.3:546.711
Alekseeva L. P., Kourova L. V., Alekseev S. E.
Specific features of using chemical treatment in removing manganese compounds from underground water
Summary
Many underground water sources in Russia used for drinking water supply are characterized by increased concentrations of iron and manganese. There are different chemical and nonchemical methods of underground water treatment. In some cases nonchemical methods of treatment cannot provide for the required drinking water quality. However, the use of chemicals for removing iron and manganese compounds makes the process more complicated and increases the cost of water treatment; therefore their use shall be substantiated and approved by technological studies. The aspects of removing manganese compounds from underground water with the use of chemicals in cases when it was stated that nonchemical methods were not efficient are considered. The results of studies on determining the efficiency of using oxidants, alkalizing and coagulating chemicals are presented. When using oxidants in removing manganese from water the range of optimal chemical dosages is relatively small. The efficiency of manganese removal with the help of oxidants increases with the increase of water pH. For more integrated removal of oxidized manganese compounds and other pollutants from water flocculants can be used in the process of water clarification.
Key words
chlorination , ozonization , deferrization , ground water , iron , manganese , coagulation , reagent
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UDC 628.161.3
Alekseev S. E., Alekseeva L. P., Kourova L. V.
Evaluation of the efficiency of different chemicals in removing iron and organics from underground water
Summary
The composition and quality of underground waters in different regions of Russia substantially differ. Most underground waters contain elevated iron concentrations. Iron from underground water that contains oxygen and high concentrations of organic substances (humic and fulvic acids) that cause the water color is most difficult to remove. Besides, in oil producing regions underground waters occur that contain pollutants of anthropogenic origin: oil products, phenols, amines etc. In the process of such water purification integrated methods shall be used to provide for eliminating organic and non-organic pollution. The results of the studies of removing iron complex organic compounds from underground water in the Nefteyugansk region by different chemical methods: oxidation, alkalization and coagulation are considered. The impact of the conditions of using chemicals on the underground water purification efficiency was determined. It was shown that in removing complex iron compounds from water strong oxidizing agents and alkalizing chemicals could be used. To eliminate humic substances and organic compounds of anthropogenic origin coagulating chemicals must be used.
Key words
ozonization , deferrization , ground water , chromaticity , iron , coagulation , permanganate oxidizability , organic substances
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UDC 628.164/.167
FESENKO L. N., Ignatenko S. I., Pchel'nikov I. V., Fedotov R. V., Tcherkesov A. Yu.
Technological and design solutions of upgrading the Don River water treatment facilities (the case of water treatment facilities of Khapry farm, Miasnikovskii district, Rostov Region)
Summary
The Don River water is used as a source of the public water supply of Rostov-on-Don, Taganrog, Novocherkassk and other cities. From January till April (during the winter freeze-up) the river water is characterized by increased total hardness (up to 10–12°) as well as by the presence of blue-green and diatom algae in concentrations reaching 100·106 c/l water in summer periods. Mechanical sieve filtration is an advanced technique of microalgae removal. Filters are installed as a rule at the very beginning of the technological process and are designed for removing coarse suspended particles, phyto- and zooplankton. Advanced microfilters are characterized by simple design, high output, compact size and low consumption of wash water; their operation is automated. In view of the high cost of ion exchange and membrane technologies and accompanying generation of considerable amounts of secondary difficult to utilize highly mineralized waste solutions the technology of hardness reduction by caustic soda softening was suggested. The expediency and efficiency of applying this method were experimentally confirmed. In case of the water treatment facilities of Khapry farm in the Rostov Region with the water intake in the lower reach of the Don River the process flow scheme of upgrading the water treatment plant providing for the water quality meeting the Sanitary Rules and Regulations 2.1.4.1074-01 was substantiated and developed. The use of this technology eliminates generation of liquid wastes subject to the discharge into the public sewer, natural water bodies or land disposal.
Key words
reagent , water treatment , phytoplankton , coagulation , caustic soda softening , microfilter
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