UDC 628.166.094.3:661.418
DOI 10.35776/VST.2023.06.01

FESENKO L. N., Pchel'nikov I. V., Pchel’nikova Anastasiia

Direct electrolysis of underground water in production

Summary

The results of production tests of flow-through electrolyzers operating in the mode of direct electrolysis of natural surface water are presented. In the process of electrolysis, sodium hypochlorite for disinfecting water is synthesized from the chlorides present in the source water. Electrolyzers are a part of the water treatment plant. Krinitsa-45 block-modular water treatment plant with a capacity of 45 m³/day has been in operation since 2020. Flow-through electrolyzers are used for the disinfection of raw water (primary disinfection) and drinking water (secondary disinfection) by direct electrolysis; they operate with current reversal in automatic mode. The oxide coating of the electrodes is OIRTA (oxide-iridium-ruthenium-titanium anode) with the addition of tantalum. In the course of studies, the process parameters of the operation of the electrolyzers were determined. The current density was changed from 25 to 75 A/m², the concentration of active chlorine was determined, and the change in the voltage on the electrolyzer terminals was recorded. The measurements were taken every fortnight during past three years. Current density 40–50 A/m² was considered as optimal in terms of efficiency since it provided for 10–12% current efficiency by chlorine and 2–2.8 mg/dm³ active chlorine concentration. Using current reversal (polarity reversal time +1 hour and –1 hour) provided for operating a flow-through electrolyzer with natural water with a total hardness of about 9–11 meq/dm³ eliminating the use of hydrochloric acid for regular washing of the electrodes.

Key words

water disinfection , membraneless electrolysis , low-concentrated sodium hypochlorite , direct electrolysis of surface water

UDC 628.387+330.322.5
DOI 10.35776/VST.2023.06.02

Vurdova Nadezhda, FESENKO L. N.

Improving the efficiency of water recycling systems at oil refineries and petrochemical enterprises (part 1)

Summary

Petrochemical enterprises produce a significant impact on the environment; therefore, they are obliged to develop and implement programs to improve the environmental sustainability; the programs have to reflect the compliance of the technological processes, equipment, technical methods, methods used at the enterprise with the best available technologies. Accordingly, the growing demand for practices of improving the effectiveness of environmental protection measures in the operation of specific economic entities stimulates the search and development of new methods as well as particular and integral indicators of the effectiveness of environmental investment projects at various levels. This study presents the results of applying proactive measures related to the implementation of an investment, environmentally oriented project for the reconstruction of water supply and wastewater disposal systems of the enterprise, development of technical measures aimed at improving the efficiency of water recycling systems, reducing the volume of effluents discharged by the plant and reducing the abstraction of raw water from the surface water source.

Key words

sewerage treatment facilities , water recycling facilities , industrial wastewater treatment , zero discharge system , pilot tests , feasibility study

UDC 628.3
DOI 10.35776/VST.2023.06.03

Koulakov A. A.

Features of wastewater composition at small-scale treatment facilities

Summary

The composition of wastewater at small-scale treatment facilities differs significantly from the composition of municipal wastewater both in terms of pollution concentrations and their proportions. Information is presented on the collection and analysis of data from long-term observations of the composition and temperature of wastewater from small settlements at 31 treatment facilities. It has been revealed that an increased concentration of nitrogen at medium concentrations of organic substances is typical for these facilities. Such a disproportion results in a shortage of substrate for biological treatment – denitrification; consequently, dosing an external source of organic matter is required. Wastewater supplied to the treatment facilities has a very low N–NH₄/N_total ratio, which indicates incomplete ammonification and the need to take into account total nitrogen during laboratory control. At some facilities, the temperature of incoming wastewater is below 10–12°C during most of the year, which significantly reduces the efficiency of biochemical treatment processes.

Key words

domestic wastewater , sewerage treatment facilities , temperature , wastewater composition , denitrifying potential

UDC 628.28
DOI 10.35776/VST.2023.06.04

Tatanov Iurii, Melekhov Roman

A modern approach to the maintenance of gravity sewers of public utilities

Summary

Most public utilities are facing typical problems associated with severe wear of wastewater collection, transportation and treatment systems, as well as with hydrogen sulfide emissions, and deterioration of the treatment facilities operation. One of the main reasons is untimely cleaning of pipelines transporting wastewater resulting in the secondary pollution of wastewater. The solution to the afore-referenced problems lies in the proper organization of the integrated maintenance of gravity sewers. The most rational combined approach to the maintenance of gravity sewers is proposed, that combines reducing the capacity of the own structures of water supply and wastewater enterprises with inviting outsourcing companies for the scheduled maintenance.

Key words

secondary pollution , wastewater transportation , sewer network wear , hydrogen sulfide emissions , deterioration of the treatment facilities operation , outsourcing professional services , integrated maintenance of gravity sewers , combined method of workflow management

UDC 628.221
DOI 10.35776/VST.2023.06.05

Volkov Sergei, Luk’ianchuk Maksim, Zhukova Anastasiia, Zhitenev A. I., Kuz’min Valentin, Rublevskaya O. N., Gvozdev V. A., Erofeev Vasilii, Kostenko I. G., IGNATCHIK V. S., Ignatchik S. Iu., Kuznetsova N. V., Fes’kova A. Ia.

Methods and results of estimating calculated rain parameters for the surface runoff disposal systems of Saint-Petersburg
Part 3. For hydraulic calculations in designing and modeling with account of the uneven distribution of rain intensities areally

Summary

Municipal surface runoff disposal systems need to be adapted to the changing climate with account of local conditions and schematic design features. In line with the world practice, one of the stages of the research in this area is the substantiation of the calculated parameters of rain for the considered climatic region. Herewith, to solve design problems, adjusting the standard climatic parameters is sufficient, whereas, to solve the problems related to the justification of decisions on the upgrade of wastewater disposal systems using calculation models, justifying the design rain profiles constituting graphs of the intensity variations over time is required. In addition, justifying the calculated parameters of rains with account of the spatial variability is needed. Beyond that, for large areas, the design rainfall parameters must be converted to average values. In world practice, this is done by multiplying the average rainfall intensity for a given duration, frequency and area by the appropriate reduction factor – areal reduction factor (ARF). In domestic practice, while designing, a similar reduction factor is also used called a correction factor that takes into account the uneven rainfall areally. However, the reliability of the values of these correction factors is very doubtful, since, for example, with a runoff area of less than 4km², the values are available only for the conditions of Moscow, whereas the origin of the values for a runoff area of more than 4km² is not known. For these reasons, in St. Petersburg, along with the assessment of the actual and prospective parameters of calculated rains used in design and modeling, the regularities of the distribution of rain intensity areally were additionally determined. As a result of the research, the hypothesis that areal and point precipitation have the same probability of exceeding was confirmed, as well as the type and parameters of the dependence were substantiated for estimating the actual values of the correction factors that take into account the unevenness of rainfall areally.

Key words

surface runoff disposal systems , flooding , adaptation measures , calculated parameters of rains , rain profiles

UDC 696.121
DOI 10.35776/VST.2023.06.06

Ландик С. В.

Siphonic roof drainage system

Summary

Architects, planners and contractors choose the siphonic roof drainage system for a wide variety of buildings and structures around the world. The indoor siphonic roof drainage system is functioning efficiently and reliably even in the heaviest rain. It requires significantly less materials and space to install than a conventional system. As a result, extra space becomes available. Architectural flexibility of design due to optimal use of space, savings during installation and operation – owing to these advantages designers choose Geberit Pluvia system. It provides for the drainage from any flat or pitched roofs, terrace roofs, and various complex roofs. In domestic practice, Geberit Pluvia indoor siphonic roof drainage system has found use in the construction of such projects as shopping centers, warehouse terminals, sports facilities, industrial enterprises and airports.

Key words

drainage from the roof of a building , gravity-vacuum storm sewer system , siphon system of an internal drain , Geberit Pluvia

UDC 628.218
DOI 10.35776/VST.2023.06.07

Chupin V. R., Skibo Denis

Substantiation of the efficiency of installing emergency storage tanks at wastewater pumping stations

Summary

Improving the reliability of wastewater disposal systems is provided by measures that prevent the intrusion of raw wastewater into the ground and spills onto the land surface. Such measures include backing up pressure and gravity pipeline sections of the network, using their accumulating capacity and installing emergency storage tanks. Based on the life cycle cost assessment, studies of the effectiveness of using emergency storage tanks at wastewater pumping stations were carried out. It is shown that with a certain length of pressure pipelines of two or more strings, the option of installing emergency storage tanks may be most economically viable. As a result, dependences of the efficiency of installing emergency storage tanks on the pressure pipeline length and pumping station capacity were obtained. For wastewater disposal systems in Irkutsk, all wastewater pumping stations are divided into two groups with emergency storage tanks and two pressure pipelines. The results of the study will be useful in updating the scheme for the development of the water supply and wastewater disposal systems of the city.

Key words

sewerage pumping station , pressure pipeline , life cycle cost , emergency storage tank , improving the reliability of wastewater disposal systems

FESENKO L. N.

XIV «TECHNOVOD–2023» International Scientific and Practical Conference

Summary

18–21 апреля 2023 г. в Кисловодске прошла XIV Международная научно-практическая конференция «Технологии очистки воды» – «­ТЕХНОВОД–2023». Мероприятие было организовано ГК «АУРАТ» (г. Москва) и ООО НПП «ЭКОФЕС» (г. Новочеркасск) при информационной поддержке Южно-российского государственного политехнического университета (НПИ) имени М. И. Платова (г. Новочеркасск) и редакции журнала «Водоснабжение и санитарная техника» (г. Москва).