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UDC 628.162.8
KINEBAS A. K., JAKOVLEV V. Ju.
Introduction of Two-Stage Scheme of Water Disinfection at Waterworks of St. Petersburg
Summary
It is told about the modernization of systems of water disinfection at waterworks of St. Petersburg using sodium hypochlorite and ammonium sulphate. It has allowed to liquidate completely the threat of affecting the city’s territory and population with highly toxic substances (gaseous chlorine and ammonia) owing to possible failures at industrial sites of the State Unitary Enterprise Vodokanal Sankt-Peterburga and at transportation of liquefied chlorine and ammonia solutions, and also to exclude chlorine and ammonia influence on the environment in the case of equipment depressurization. Introduction of the technology of water disinfection with ultra-violet irradiation has favored the realization of the concept of multiple barriers at potable water disinfecting at the city’s waterworks.
Key words:
potable water , disinfection , liquefied chlorine , sodium hypochlorite , ammonia water , ammonium sulphate , ultra-violet irradiation
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UDC 628.166.085
Kostyuchenko S. V., SMIRNOV A. D., Pokhil Yu. N., Bagaev Iurii
Introduction of UV-disinfection at the Novosibirsk wastewater treatment facilities
Summary
Water recycling in the modern municipal services is a comprehensive task. On one hand the city inhabitants should be supplied with high-quality drinking water meeting all the sanitary and hygienic requirements; on the other hand the discharged municipal effluents shall not produce any adverse effect on the environment. To fulfil these tasks the most advanced disinfection technologies that ensured meeting all the microbiological requirements to the drinking water and effluents were introduced at the Novosibirsk water and wastewater treatment facilities. The use of ultraviolet irradiation provided for the efficient multi-barrier protection in drinking water purification and environmentally safe disinfection of wastewater.
Key words
chlorination , disinfection , wastewater , water supply , water disposal , ultraviolet irradiation
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UDC 628.166.085
Vasiliak L. M., SMIRNOV A. D.
Potential use of ultrasound in water disinfection
Summary
Ultrasound has been used long enough in engineering and medicine for diagnostics, visualization of underwater objects, surface cleaning and other systems. Using ultrasonic disinfection as a main or additional technology is impractical because of the long exposure time, high energy consumption and lack of regulatory documents. To improve the efficiency of disinfection equipment the manufacturers suggest additional ultrasonic water treatment in combination with oxidizers and UV irradiation. The data on possible use of ultrasonics both as an additional disinfection method and method of improving the efficiency of traditional technology from the point of view of the concept of establishing numerous barriers during disinfection is presented. Different types of ultrasonic effect for using in water disinfection systems are considered. Ultrasound provides for the extremely low disinfection efficiency compared to other traditional technologies, therefore it is not used as an independent method. Ultrasonic water treatment improves the efficiency of oxidation technologies. Combined action of ultrasonics and UV irradiation does not have any synergistic effect. For natural water and effluent after treatment according to the operating standards the standard UV dosages are sufficient to ensure meeting the microbiological standards. Additional ultrasonic treatment is advisable under special conditions. Quartz sleeves can be well cleaned with mechanical systems and chemical wash which is used by all the world leading manufacturers. Due to the particular hazard of ultrasonic contact impact on humans the process of ultrasonic treatment shall completely eliminate such potential effect.
Key words
disinfection , ultraviolet , wastewater , natural water , water treatment , ultrasound , chlorination agent
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UDC 628.161:66.081.63
DOI 10.35776/VST.2024.01.02
Pervov A. G., Spitsov D. V., Tet Zo Aung, Medved’ko Viktoriia
Use of the reverse osmosis method for the preparation of concentrated sodium chloride solutions for the production of sodium hypochlorite
Summary
The use of membrane reverse osmosis and nanofiltration plants for the production of drinking water is described. It is noted that using hypochlorite obtained by the electrolysis of concentrated solutions of table salt is an effective method of disinfection in drinking water supply systems. A new area of application of reverse osmosis systems is considered, i. e., the preparation, in addition to clean water, of concentrated solutions of sodium chloride used for the production of sodium hypochlorite to reduce the operating costs of a drinking water treatment plant eliminating the purchase of the chemical, i. e., table salt. A process flow scheme of the proposed technology is presented, that involves cascade processing of the source water using nanofiltration membranes of low selectivity to provide for separating the concentrate into the solutions of monovalent and divalent ions. The experimental procedure is described and experimental dependencies are presented to determine the efficiency of the concentrate separation. Based on the results of the experiments, an economic calculation of the costs of designing an additional system for producing concentrated solutions was performed proving the economic efficiency of the proposed process compared to the use of table salt.
Key words
disinfection , sodium hypochlorite , reverse osmosis , reverse osmosis unit , nanofiltration , concentrate utilization , water treatment , electrolysis method
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DOI 10.35776/VST.2021.12.04
UDC 628.166:541.135
Pchel'nikov I. V., Nguen Tkhi Tuan Z’ep, FESENKO L. N.
Study of the current waveform effect on the formation of cathode deposits during direct electrolysis
Part 2. Electrolysis of sea water
Summary
Sodium chloride is a raw material for the production of sodium hypochlorite; however, the cost of its purchase and delivery is up to 25–30% of the total cost of the disinfectant produced. An alternative raw material for the production of sodium hypochlorite can be chlorides present in natural mineral water, e. g., underground, sea and oceanic water. Mineral water will be the raw material for obtaining sodium hypochlorite solution of a sufficiently high concentration that can then be added to the treated water. The experience of operating CHLOREFS units manufactured by EKOFES SPE LLC showed that the main problem related to the electrolyzer operation reliability is associated with the formation of deposits of hardness salts – calcium carbonate on the surface of the cathodic electrode, and magnesium hydroxide on the surface of the electrolyzer cathodes. This results in a negative electrolysis regime, an increase in voltage, overheating and warping of the electrode system, destruction of the oxide coating of the anodes, etc. The results of studies of direct electrolysis by direct and reverse current of salt water of the South Vietnam Sea are presented. During the tests the effect of reverse current in comparison with direct current on the reduction of the formation of insoluble substances on the cathodes of the electrolyzer was estimated, and besides, the electrolysis process parameters were determined. The current chlorine yield for seawater was above 100% in the reverse mode with a current density of 100 A/m2.
Key words
disinfection , water treatment , sea water , sodium hypochlorite , direct electrolysis with constant and reverse current
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DOI 10.35776/VST.2021.10.02
UDC 628.166:541.135
Pchel'nikov I. V., Nguen Tkhi Tuan Z’ep, FESENKO L. N.
Study of the current waveform effect on the formation of cathode deposits during direct electrolysis.
Part 1. Electrolysis of fresh water
Summary
During the electrochemical processing of chloride-containing natural water in a membraneless electrolyzer, salts of hypochlorous acid are formed that are exhibiting oxidizing properties. This process is widely used for the production of sodium hypochlorite disinfectants. The raw material for the production of sodium hypochlorite can be not only artificially prepared saline solutions, but also natural mineral water containing chlorides. The electrolysis of such solutions results in the formation of insoluble calcium and magnesium salts at the cathode of the electrolyzer thus inhibiting mass transfer in the interelectrode space and the occurrence of emergency situations. The first part of the article presents the results of studies of direct electrolysis of fresh water with constant and reverse current in Dong Hoi city, Republic of Vietnam. In the conducted tests the effect of reverse current in comparison with direct current on the reduction of the formation of insoluble substances at the cathodes of the electrolyzer was determined. The experiments have shown the advantage of reverse current over direct current. So, during the electrolysis with reverse current for a period of up to 6 hours, the amount of deposits on the electrodes did not increase, however, with direct current the deposits accumulated from the very beginning of the electrolysis process. This is due to the fact that the precipitate formed during the cathodic half cycle is dissolved during the anodic half cycle by acid, a product of water oxidation. The current output of chlorine for tap water was no more than 23% with a current density of 100 A/m2.
Key words
disinfection , water treatment , sodium hypochlorite , direct electrolysis with constant and reverse current , fresh water
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UDC 628.17.001.4
Pchel'nikov I. V.
Research and development of the technology for the production of electrolytic sodium hypochlorite by electrolysis of seawater
Summary
Chlorination continues to be the most widely used method of water disinfection in the world owing to the sanitary-hygienic reliability, relative simplicity and economic efficiency. The toxicity of chlorine, the need for the transportation through the residential areas, as well as storage under excessive pressure served as the basis for the search for alternative ways to ensure industrial safety and anti-terrorist sustainability of water supply systems. Among the chemicals alternative to chlorine, electrolytic sodium hypochlorite obtained at the point of consumption by electrolysis of an aqueous solution of sodium chloride takes the first place. The use of natural water containing chlorides as a raw material for the production of sodium hypochlorite is most promising. The use of natural water simplifies essentially the process flow scheme and provides for abandoning the purchase of sodium chloride which reduces the cost of the finished product. The results of research and development of the technology for producing electrolytic sodium hypochlorite by direct electrolysis of the Black Sea water are presented. The expediency of the technology was experimentally confirmed and the optimal conditions for the production of sodium hypochlorite by electrolysis of seawater were determined. The results of the study of deposits formed on the cathodes during the electrolysis of the Black Sea water are presented. Recommendations for the selection of process flow schemes for the production of sodium hypochlorite by electrolysis of seawater have been compiled.
Key words
disinfection , sodium hypochlorite , sea water , electrolyzer , direct electrolysis of seawater , electrode
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UDC 628.166
Pchel'nikov I. V., Nguen Tkhi Tuan Z’ep
Study of the optimal electrolysis mode while producing sodium hypochlorite from Mediterranean Sea water
Summary
The theoretical substantiation, as well as the research results of developing the technology for producing low-concentration sodium hypochlorite by direct electrolysis of Mediterranean water for the biocidal treatment of the cooling circuit of nuclear and thermal power plants are presented. The optimal process parameters have been determined. Methods for preventing the formation of cathode deposits have been studied. It has been established that during the electrolysis of seawater with an anode current density of 1000 A/m2 the maximum concentration of active chlorine 7.9 g/dm3 can be achieved; whereas at 600 A/m2 – up to 6.8 g/dm3 is achieved on iridium-ruthenium-titanium oxide anodes. The current chlorine yield is within 10%. It has been shown that the current chlorine yield and specific power consumption per 1 kg of generated active chlorine reach their optimum values (85–90% and 3–3.5 kWh/kg) at an active chlorine concentration in the electrolysis product of 2 ± 0.2 g/dm3. This determines the process and economic feasibility of producing sodium hypochlorite from sea (ocean) water.
Key words
disinfection , decarbonization , low-concentrated sodium hypochlorite , membraneless electrolysis , inhibition , acid-washing , electrolysis of Mediterranean water
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UDC 628.166.085
SMIRNOV A. D., Strelkov A. K., Tkachev Andrei
Revisiting the selection of wastewater disinfection technology
Summary
Environmental law enforcement in relation to discharging chlorine and organochlorine contaminants induces the use of advanced safe and efficient chlorine free methods of wastewater disinfection. The use of ultraviolet irradiation provides for meeting all the requirements imposed on the technology of wastewater disinfection eliminating any adverse impact on the environment. The use of this technology eliminates possible penalty charges for polluting the environment with chlorine and organochlorine contaminants. The economic comparison of two disinfection methods (the application of sodium hypochlorite and UV-irradiation) reveals significant operational benefit when introducing UV-disinfection. Annual savings of operational expenditures is 50% and more at the comparable capital expenditures. The advantages of UV-disinfection are as follows: efficiency in relation to all types of indicator and pathogenic microorganisms, whereas chlorine-containing chemicals do not often ensure fair efficiency in viruses and protozoa elimination; no by-products are generated; no adverse impact on the water bodies is produced (consequently, no penalties); no threat of overdosing; easy and simple control over the disinfection process; no need in dosing system and additional control systems; disinfection effect independence from fluctuations of effluents quality within the limits of the design parameters; minimum footprint; no additional facilities are needed (e. g., contact tank for dechlorination); possible retrofitting into the existing buildings or facilities, for example, in the process of wastewater treatment facilities upgrade and chlorination replacement; low operational expenditures (lamp replacing once in a year and a half – two years and energy saving). In this context switching to chlorine free disinfection technologies that eliminate the formation of organochlorine contaminants is a correct solution.
Key words
chlorination , disinfection , wastewater , dechlorination , ultraviolet irradiation , effluents charge
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УДК 628.316.6:628.166
DOI 10.35776/VST.2024.04.01
Pokhil Yu. N., Novoshintsev V. N., Kostyuchenko S. V., Volkov Sergei, Tkachev Andrei
Комплексное решение проблем обеззараживания природных и сточных вод в современных условиях в масштабах г. Новосибирска
Аннотация
Рассматриваются основные аспекты практического применения технологических решений в сфере обеззараживания природных и сточных вод, позволяющих обеспечить современные нормативные и законодательные санитарно-эпидемиологические требования, на примере МУП г. Новосибирска «ГОРВОДОКАНАЛ». В системе водопровода и канализации г. Новосибирска создан один из крупнейших в России комплексов обеззараживания природных и сточных вод с применением УФ-излучения общей производительностью 1 650 000 м3/сут. В системе водоснабжения города внедрена современная мультибарьерная технология, предусматривающая комбинированное применение УФ-излучения и хлорирования, позволяющая создать надежный барьер в отношении всех типов вирусов, в том числе вируса COVID-19 (SARS-CoV-2), и цист патогенных простейших. В результате применения УФ-обеззараживания питьевой и сточной воды обеспечивается соблюдение новых санитарных правил и норм СанПиН 1.2.3685-21 «Гигиенические нормативы и требования к обеспечению безопасности и (или) безвредности для человека факторов среды обитания». Обеззараживание сточных вод на городских очистных сооружениях канализации г. Новосибирска УФ-излучением полностью удовлетворяет требованиям по применению наилучших доступных технологий, сформулированных в Информационно-техническом справочнике ИТС 10-2019 «Очистка сточных вод с использованием централизованных систем водоотведения поселений, городских округов». На УФ-станциях применено УФ-оборудование отечественного производства на основе современных мощных амальгамных ламп низкого давления. Комплексное и своевременное применение современной технологии обеззараживания УФ-излучением как при водоподготовке, так при очистке сточных вод на объектах МУП г. Новосибирска «ГОРВОДОКАНАЛ» обеспечило выполнение самых строгих современных требований санитарного и экологического законодательства РФ.
Ключевые слова
potable water , disinfection , ultraviolet , wastewater , best available techniques , multi-barrier technologies
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UDC 628.166.094.3
Grabovskii P. A., Gorobchenko A. I.
Adaptive control method in water disinfection
Summary
Pathogenic microorganisms present in natural water sources can be partially removed in the process of physical and chemical treatment (coagulation, contact clarification, filtration with presedimentation or flotation and other methods). Their final inactivation can be provided by oxidation with chlorine, chlorine dioxide, sodium hypochlorite and chloramines, ozone, as well as by UV-irradiation. The problems arising during chemical water disinfection are considered. The actuality of the problems is related to the decrease in water consumption, in big cities in particular. Owing to this the time of water retention in the distribution network increases, and in the far points the concentration of disinfectants in water is unacceptably low. The complexity of determining the chemical dosages conditioned by continuous fluctuations in the water consumption and water quality is shown. The operation of a network with the use of EPANET 2.0 software was simulated. The disinfectant concentration changes in water along the network length for «short» and «long» sections were studied. The dosing patterns for a network with two disinfectant injection points were developed. The practicability of adaptive control of the disinfection process is shown and its algorithm has been developed. The introduction of the proposed control scheme will provide for not only economic benefit by reducing chemical consumption but also for improving the reliability of water disinfection, improving the quality of the disinfected water, developing the data base for optimization and predictions, improving the customer service level.
Key words
mobile laboratory , disinfection , optimization , water treatment , adaptive control , algorythm
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DOI 10.35776/MNP.2019.10.09
UDC 628.3:62-278
Kofman V. Ya.
Micromotors – a recent trend in developing water and wastewater treatment technologies (a review)
Summary
Micromotors are autonomous, performing certain functions, self-propelled microdevices based on inorganic, organic or biological materials. Implemented in a micromotor design are two functions: autonomous movement and effective capture and/or destruction of various chemicals, including pollutants. To ensure autonomous movement the micromotor device provides for the creation of local thermal, acoustic, chemical gradients arising from asymmetric morphology or surface structure. The movement is provided through the use of various energy sources including light, electric and magnetic fields, ultrasonic waves or chemical “fuel”. The chaotic trajectory of micromotors throughout the solution provides for the highly efficient interaction of the chemicals immobilized on their surface with the targeted pollutants or detectable substances. The most elaborated principle of creating autonomous movement is the generation of a recoil impulse at asymmetric formation of gas microbubbles as a result of a chemical reaction. Currently, the main studies on the use of micromotors in water purification processes are carried out in the areas of analysis of aqueous media, removal of heavy metals, organic pollutants, dyes and oil products, as well as water disinfection. It is estimated that micromotors possess unique capabilities in the field of detection and removal of pollutants in aqueous media due to a combination of adsorption and catalytic properties with autonomous movement.
Key words
disinfection , adsorption , water and wastewater treatment , micromotors , autonomous movement , catalysis , removal of pollutants
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UDC 628.3.004.69
Modernization and Reconstruction of Sewage Treatment Facilities of the Municipal Unitary Enterprise Vodokanalof the City-Resort of Anapa
Summary
Features of the wastewater treatment in resort towns are described. The ways of enhancement of operation efficiency of sewage treatment facilities of the MUE Vodokanal of the city-resort of Anapa are considered. A brief characteristic of two variants of modernization of treatment facilities are presented. The first variant stipulating the partial replacement of equipment makes it possible to reduce expenditure and enhance efficiency of wastewater treatment at the most unsatisfactory operating parts of the flow chart. The second variant demands significant capital investments, changes in the flow chart and replacement of equipment, but at the same time economic efficiency and the required quality of wastewater treatment according to all the indicators are achieved.
Key words
disinfection , treatment facilities , biological treatment , sewerage , nitri-denitrification , flow chart , aftertreatment
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UDC 621.357.1:628.162.8
KINEBAS A. K., JAKOVLEV V. Ju., NEFEDOVA E. D., Lobanov Fedor
Water Disinfection with Weak Sodium Hypochlorite at Water Supply Stations of St. Petersburg
Summary
The method of water disinfection with sodium hypochlorite produced from common salt solution using the electrolysis method at the place of use has been introduced at two largest water supply stations, Southern and Northern, of St. Petersburg. The use of sodium hypochlorite of low concentration makes it possible to avoid the necessity of transportation and long-term storage of a ready solution. The technology introduced makes it possible to minimize considerably the risk existing in the case of the use of liquefied chlorine and reduce the operation expenses comparing with strong solutions of sodium hypochlorite.
Key words:
disinfection , sodium hypochlorite , weak solution , electrolysis , common salt , softened water , process automation
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UDC 628.166.094.3:661.418
DOI 10.35776/VST.2023.09.06
Gao Yuan, NEFEDOVA E. D., KINEBAS A. K., Lobanov Fedor
Disinfection of water with low-concentration sodium hypochlorite
Summary
An advanced safe technology for the production of low-concentration sodium hypochlorite from salt brine is considered. The main stages of the technological process are described in detail. Particular attention is paid to the issues of industrial safety and reliable operation of electrolyzers – units for the preparation of sodium hypochlorite at the Southern and Northern water treatment facilities of SUE «Vodokanal of St. Petersburg». The use of low-concentration solutions of sodium hypochlorite provides for improving the safety of water purification processes. Salt is the raw material for the production of sodium hypochlorite. Since the chemical is used directly at the place of production, there is no need for transportation. The combination of disinfection of treated water with low-concentration sodium hypochlorite (first stage) with ultraviolet irradiation (second stage) before supplying it to the city water supply network guarantees full compliance of water quality in terms of microbiological indicators with current standards and its high epidemiological safety.
Key words
disinfection , water treatment , sodium hypochlorite , epidemiologic safety
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UDC 628.166:628.1.033 (470.61-25)
FESENKO L. N., Ignatenko S. I., Skryabin A. Yu., Fedotov R. V.
Ensuring of Wastelessness and Ecological Compatibility of Technology of Sodium Hypochlorite at the ChlorefsUnits
Summary
The ways of solving the problem of ensuring of wastelessness and ecological compatibility of the technology of large-tonnage production of sodium hypochlorite at electrolysis stations of high-capacity water treatment facilities are considered. It is shown that for conditioning of water used for preparation of salt solutions the method of acid decarbonization is more preferable as excluding the generation of some accompanying waste water. It is considerably cheaper than the cationite softening and makes it possible to use the salt of any quality. The saturators for preparation of saturated salt solution should be equipped with the washing systems similar to high-rate water supply filters with wash water discharge into the system of treatment and its reuse in the scheme of dissolution.
Key words
disinfection , sodium hypochlorite , electrolysis , wash water , dissolution , cationite softening , decarbonization
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UDC 628.162.5.001.2
Ganbarov E. S., Safarova A. S.
Treatment of Wash Water of Filters and Water Disinfection at Water Treatment Complexes of the Azerbaijan Republic
Summary
Results of studies carried out for determination of efficiency of clarification and investigation of influence of quantity and quality of the wash water supplied to a head of treatment facilities on the subsequent process of treatment are presented. For full disinfection of water it is proposed to use a disinfectant received by electrolysis of a solution of salts of alkaline metals and mineralized ground water directly at the territory of water treatment station.
Key words:
disinfection , wash water of filters , clarification , settling , filtration , reagent treatment
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UDC 628.16/.31.085
IVANOV A. S.
Determination of the Minimal Efficient Doze of UV-Irradiation
Summary
The process of study of water for optimal and valid choice of power of the ultraviolet irradiation system is described. The effectiveness of water treatment by ultraviolet irradiation depending on the content of suspended particles in water is shown. A diagram of the dependence of performance of ultraviolet disinfection on the water transmission coefficient is presented. The necessity of conduction of the preliminary model ultraviolet irradiation and drawing up of the conclusion before the delivery of equipment to the real object of the customer is substantiated.
Key words
disinfection , ultraviolet , wastewater , water treatment , disinfection
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UDC 628.16.065.2-926:628.16.094.413.094.3
Pokhil Yu. N., Bagaev Iurii, Mamaev V. V., Novoshintsev V. N., Valuyskikh I. V., Zhagin V. A., Boldyrev Viacheslav Viktorovich, Shokolov A. N., Belousova T. V., Smirnov V. P.
Optimization of flocculation and chlorammoniation processes at the water treatment facilities of the city of Novosibirsk
Summary
The results of long-term studies to improve the design and operating parameters of the pumping-filtration stations in Novosibirsk are presented. The schemes of the developed processes and technical means for the enhancement of disinfection and flocculation are given. The results of research on improving the processes of mixing and flocculation to provide for reducing the consumption of coagulant by more than 50% without water quality degradation achieving precipitation of the major sludge amount in the flotation chambers and at the entry of the sedimentation tanks, respectively, reducing the pollution load on filters and water consumption for their backwash. Based on the results of the research on the improvement of the technology of chlorammoniation a predictable and well-controlled process has been developed with a guaranteed decrease in the concentration of chlororganic compounds within the limits of the MPCs as well as the elimination of chloramines with the highest degree of oxidation and nitrification. The process ensures the reduction of secondary water pollution and bacteriological and hydrobiological pollution of the water treatment facilities.
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Key words
disinfection , water treatment , intensification , flocculation , chlorammoniation , mixing , stoichiometric calculation
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