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UDC 628.218

Karmazinov F. V., Zhitenev A. I., Shunto I. P., Kuz’min Valentin, Spivakov M. A., Pulin O. V., IGNATCHIK V. S., Ignatchik S. Iu., Kuznetsova N. V.

The use of stochastic methods in determining the required capacity of regulating units in combined sewers

Summary

The flows of wastewater removed by the combined sewers are characterized by high irregularity caused by the random nature of rainfall and snow melting. One of the ways of improving the reliability of these systems is the introduction of flow regulating units. They have been designed to diverse wastewater between the sanitation districts in case of emergency or in case of the actual wastewater inflow in one of them, e. g. because of over-estimated rainfall, exceeding the actual capacity of the regulating units. The method of determining the required capacity of the flow regulating units with the use of stochastic methods was developed. By the example of the wastewater disposal system of Saint-Petersburg it was stated that the required supply of the sewage pumping station (SPS No. 6) functioning as a regulating unit between the left-bank and right-bank sanitation districts was of random nature and was distributed according to the exponential law with the increasing probability of using the modes with lower supply.

Key words

sewerage pumping station , capacity , combined sewer , flow regulating unit , stochastic method , unsteady random flow

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UDC 628.211:53.072.12

Karmazinov F. V., Zhitenev A. I., Shunto I. P., Kuz’min Valentin, Kostenko I. G., Martiugin V. A., Pulin O. V., IGNATCHIK V. S., Ignatchik S. Iu., Kuznetsova N. V., Fes’kova A. Ia.

Specific features of hydraulic mode simulation for combined sewers

Summary

Hydraulic simulation of sewerage networks in big cities in practice involves input of large quantities of data on all the network sections including the yard ones. This complicates significantly and extends the time required for fulfilling the task. Therefore developing express-method of hydraulic simulation of transporting facilities of sewers will provide for reducing the amount of input information without reducing the accuracy of the calculation results. In order to substantiate the method experimental studies in one of the sanitation districts of Saint-Petersburg were carried out. By experiment it was stated that the use of simplified hydraulic simulation with account of only street networks (without the yard ones) resulted in 20% overestimation of the calculated flows. Herewith the express-method of calculating wastewater flows in combined sewers depending on the rainfall intensity that allows the use of hydraulic simulation with account of only street networks where virtual tanks are simulated with a capacity equal to the capacity of the yard networks connected to them has been experimentally substantiated. The method error is 2–5%.

Key words

sewerage pumping station , capacity , combined sewer , flow regulating unit , stochastic method , unsteady random flow

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UDC 628.21/.25

Perminov N. A., Vasilyev V. M., Stolbikhin Iu. V., Perminov A. N., Klementyev M. N.

Geotechnical and technological aspects of ensuring the safety of tunnel sewers under the conditions of loose ground of Saint-Petersburg

Summary

Intensive development of metropolitan cities calls for the sustainable operation of the municipal underground infrastructure facilities. Special protection is needed for tunnel sewers of long-term serviceability. Both external and internal factors can influence accidents on sewers. Among the causes of sewer deterioration the following can be identified: sewer trough wear, physical and mechanical structural damages caused by external factors and impact of chemically aggressive wastewater. However, corrosion processes in sewers pose the key problem. The main specific feature of the big sewer operation is the process of microbiological (gas) corrosion of concrete and fittings as well as the technical equipment of the shafts. The defect symptoms are presented together with the new methods of tunnel sewer diagnostics based on the sophisticated materials of their operation under the conditions of loose ground and intensive man-induced impact. The geotechnological methods of protecting tunnel sewers of long-term serviceability have been developed. The unrivalled experience of using these methods at the St. Petersburg facilities with monitoring support is presented. The system of sewer testing has been developed; the basic methods of protection against deterioration have been presented. The most widely used methods of tunnel sewer protection in Saint-Petersburg are so called passive. They are based on the advanced choice of corrosion-proof materials in direct contact with corrosive media. The importance of combined geotechnical and internal monitoring of tunnel sewers is shown.

Key words

monitoring , corrosion , tunnel sewer , man-induced impact , geotechnical and technological methods of protection

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UDC 628.11(470.6)

Mikheeva I. V.

Water projects, water supply and wastewater disposal conditions in the communities of the Southern Federal District

Summary

Drinking water quality maintenance has been one of the priority tasks of the national sanitary and epidemiologic service activities. The population practically in all the territorial entities of the Southern Federal District suffers from the scarcity of pathogen-free drinking water because of the undercapacity of the waterworks, unsatisfactory sanitary condition of the drinking water transportation systems, inefficient use of drinking water for watering garden plots in summer, lack of the good quality water supply sources. The root cause of water sources pollution is the discharge of poorly treated effluents and raw wastewater, storm water, drainage water from irrigation systems into the water bodies. The source of sea water pollution is raw wastewater and poorly treated effluents discharged by inefficient wastewater treatment facilities. Most wastewater treatment facilities, sewers of different projects and communities on the territory of the Southern Federal District need rehabilitation, capital repair and upgrade. Drinking water quality depends on the condition and quality of the water source, water treatment technology and condition of the distribution networks that predetermines the need of water use optimization. The proposals on improving the condition of water supply and wastewater disposal and ensuring the epidemiological welfare of the population of the communities of the Southern Federal District are presented.

Key words

potable water , treatment facilities , water supply , ground water , water disposal , surface water , sanitation-and-epidemiological safety , water bodies

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UDC 628.161.3

Getmantsev S. V., Sychev A. V., Getmantsev V. S.

Prospects of coagulation water treatment

Summary

Despite the significant progress and increasing popularity of membrane water treatment methods chemical treatment keeps hol­ding tightly its position. One of the most important characteristics of coagulants based on polyaluminium chloride is the basicity. The basicity, all other conditions being equal, determines the dealkylation rate and pH of water subject to coagulation. The value of pH obtained after coagulant hydrolysis, in its turn, determines the zeta potential of colloids present in water and kinetic persistence of the colloid system. During coagulation each type of colloid water pollutants has corresponding optimal pH value. The development of the technology of polyaluminium chloride production from high-purity metallic aluminium by «Aurat» JSC resulted in market launch of EPOKHA™ coagulant trademark with 40–83% basicity. The use of EPOKHA™ provides for choosing an optimal modification of polyaluminium chloride for every customer and every climatic season. Another new product manufactured by «Aurat» OJSC under GranEKO™ trademark is crystalline aluminium chlorhydrate with 65–83% basicity. The concentration of active matter in such product is up to 50% as Al₂O₃. High basicity provides for using GranEKO™ for the clarification of water with low alkaline reserve eliminating the use of alkalizing agents. An important trend in developing chemical water treatment means is the development of composite chemicals combining inorganic coagulant and organic polyelectrolyte. New composite chemicals of ERCHV™ series present a combination of coagulant based on aluminium salt, polydiallyldimethylammonium chloride and modifying additives that provide for the synergetic effect and storage stability. The variety of characteristics of water subject to treatment and applied process flow schemes require an integrated approach to the problem of pH correction during coagulation by using coagulant with higher or lower basicity and changing the injection point.

Key words

coagulation , residual aluminium , aluminium sulphate , aluminium polyoxychloride , chemical water treatment methods , basicity

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UDC 628.16.087

FESENKO L. N., Skryabin A. Yu., Bessarabov S. Iu., Pchel'nikov I. V., Ignatenko S. I.

Utilization of concentrate from reverse osmosis units  in the production of electrolytic sodium hypochlorite

Summary

Owing to high efficiency and minimum chemical consumption reverse osmosis and nanofiltration have been widely used in process flow schemes of drinking water demineralization and softening and water preparation for industrial use (in steam boiler-houses, recycling cooling circuits, heat network make up etc.). However, the methods of membrane separation are accompanied by concentrate generation which is very difficult to process and utilize. The data on utilization of concentrates of membrane separation units with obtaining chloride-sodium raw material for the production of electrolytic low-concentrated sodium hypochlorite is presented. Since the waste stream of reverse osmosis units contains elevated concentrations not only of chloride ions but also of Са²⁺, Mg²⁺, НCO^3- and SO₄^2- ions it would be reasonable at the first stage to reduce the amount of process concentrate by repeated concentrating as per flowchart «nanofiltration-reverse osmosis». Further on the concentrate of nanofiltration containing mainly Са²⁺, Mg²⁺ and SO₄^2- divalent ions is subject to chemical treatment as per flowchart: at the first stage with barium compounds; at the second stage with sodium carbonate and hydroxide. This will allow separating practically insoluble BaSO₄ from the solution with its precipitation in a vortex reactor or first-stage lamellar separator; then CaCO₃ and Mg(OH)₂ low-soluble in alkaline environment are precipitated in the second stage reactor. BaSO₄, CaCO₃ and Mg(OH)₂  insoluble salts removed from the mass balance are dewatered in a filter-press and sold as commodity or raw products. Aqueous solution of sodium chloride is repeatedly concentrated by three-stage reverse osmosis to obtain 2–2.5% aqueous solution of table salt – high-grade raw material for the production of electrolytic sodium hypochlorite with 6–8 g/l chlorine equivalent concentration. Chlorine-containing product can be used for drinking and waste water disinfection, biocidal processing of cooling to­wers, heat exchanging units for preventing and removing biofouling, washing ultra-and microfiltration membranes, disinfecting water treatment facilities and equipment, pipelines and other components used in the production of drinking and process water.

Key words

sodium hypochlorite , concentrate , reverse osmosis , nanofiltration , desulfatation , chemical softening

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UDC 628.165:66.081.63

Kurdiumov V. R., Timofeev K. L., Kraiukhin S. A.

Specific features of using reverse osmosis for mine water treatment

Summary

The possibility of using reverse osmosis for treatment of mine water from dead copper-nickel pits was studied. The composition of mine water was, mg/dm³: Mn 0,6–1; Fe 0,01–0,1; Ni 0,8–1,5; Cu 0,3–0,5; Zn 0,05–0,25; Co 0,02–0,07; Na 35–50; Ca 125–150;
Mg 35–45; SO4 100–200; Cl 65–75; Al 0,02–0,05; Si 9–11; Se 0,1–0,2; As < 0,005; Te < 0,005; Pb < 0,005; Hg < 0,00005; salt content 750–850; total hardness 9.5–11.5 °dGH; рН 7–7.5. The studies were carried out in a pilot plant with a capacity of 1 m³/h with original mine water. The plant included ultrafiltration and reverse osmosis modules. The permeate yield varied in the range of 50–75% of the original water volume. The method of chemical mine water demanganation and de-ironing at the primary treatment stage was tested. The quality of effluent (permeate) fully conforms to the drinking water requirements. The operating conditions of the pilot plant are described; the chemical unit consumption is presented. The specific features of using reverse osmosis technology for mine water treatment are described. The basic performance indicators of the reverse osmosis unit in terms of the equivalent amount of 1 m³/h at
the effluent output of 75% of the inflow are presented. The method of concentrate utilization is described providing its yield is reduced to 5% which makes it possible to extract valuable admixtures (non-ferrous metals).

Key words

deferrization , reverse osmosis , ultrafiltration , stability index , demanganization , concentrate utilization , mine water , non-ferrous metals

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«On the experience of upgrading water supply
and wastewater disposal systems in public utilities
and industries» Conference Results

Аннотация

Научно-практическая конференция, которая проходила в г. Ялте 1–5 октября 2018 г., стала постоянной рабочей площадкой Российской ассоциации водоснабжения и водоотведения для своевременного решения актуальных задач отрасли и подтвердила международный статус ввиду участия коллег из КНР, Белоруссии, Казахстана. Конференция поддержана главой Республики Крым С. В. Аксеновым и собрала 150 участников: ученых, специалистов, практиков, экспертов отрасли.

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«ECWATECH–2018»

Аннотация

Тематика форума «ЭКВАТЭК» охватывает широкий спектр вопросов, связанных с коммунальным и промышленным водоснабжением, водоподготовкой и очисткой сточных вод, обработкой осадка, строительством и эксплуатацией трубопроводных систем и водохозяйственных сооружений. В течение трех дней специалисты водной отрасли обменялись опытом и информацией, а посетители ознакомились с новейшими технологиями и решениями для водохозяйственного комплекса.