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Number 6 / 2020
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DOI 10.35776/MNP.2020.06.01
UDC 628.1:543.31
Vozhdaeva M. Iu., Kholova Al’fiia, Trukhanova N. V. , Melnitsky I. A., Kantor E. A., Beloliptsev I. I.
Estimation of the variability of the chemical composition of drinking water transported by water distribution networks
Summary
While estimating the reliability and efficiency of water supply and sanitation utilities, transporting drinking water to the consumer requires closer attention due to possible quality deterioration during long transportation time, as well as in dead-end and local stagnant zones of distribution networks. It was revealed that the values of the general chemical indicators in drinking water during its transportation are quite sound. An exception is the turbidity of drinking water from surface water intakes and the hardness of drinking water from infiltration water intakes. Statistical criteria obtained during long-term data processing (the range of variation in metal concentrations, standard deviation and the shape of the density distribution graphs of their concentrations) evidence greater stability in the composition of drinking water in networks compared to water in clean water tanks at water intakes. A close to normal distribution of the concentration values of the selected indicators suggests the absence of significant random factors affecting the quality of water in the networks. Dead ends and local stagnant zones of networks are exposed to corrosion processes occurring inside pipes, which is confirmed by higher values of the Langelier index in water samples from these zones. In general, drinking water from surface water intakes is characterized by a wide scatter in the concentrations of the components and is more corrosive compared to the water from infiltration water intakes. Water in stagnant and dead-end zones of water distribution networks has raised turbidity and contains increased concentrations of iron and zinc. Relative to the current water quality standards, the concentration values were at a stable acceptable level in any sampling point, which is confirmed by the range of variation in concentrations during the whole observation period (2006–2016).
Key words
potable water quality , Langelier index , water distribution network , danger coefficient , water corrosiveness
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DOI 10.35776/MNP.2020.06.02
UDC 628.2/.4:006.3:349.6
Vereshchagina Lidiia
On the need for revising the Code of Practice CP 32.13330.2018 «Sewerage. Pipelines and wastewater treatment plants» regarding the design of systems for the disposal and treatment of surface runoff from settlements
Summary
The regulatory framework for the design of systems for the disposal and treatment of surface runoff from the territory of settlements and industrial sites is discussed, in particular, the practice of applying the Code of Practice CP 32.13330.2018 «Sewerage. Pipelines and wastewater treatment plants. SNiP 2.04.03-85», enforced by the order of the RF Ministry of Construction of June 26, 2019. Structural changes of the regulatory document are considered, as well as the most common problems that design organizations and the state authorities of project expertise have to face while applying separate provisions in designing engineering structures for disposal and treatment of surface runoff from settlements. A list of the main paragraphs of CP 32.13330.2018 that require revision with the respective comments is presented.
Key words
treatment facilities , surface runoff , storm sewer , hydraulic calculation of networks , separation chamber , intermediate storage tank
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DOI 10.35776/MNP.2020.06.03
UDC 628.2/.4:006.3:349.6
Grigor’ev A. V., Vasen’kina Elena, Kravets E. A.
Regulation of the permissible discharges of pollutants into water bodies established by the federal legislation and feasible directions of its improvement
Summary
The analysis of the legal support for the regulation of permissible discharges of pollutants into water bodies has been conducted together with the mechanism of payment for the negative impact on water bodies. Inconsistency was revealed in the approach to regulating permissible discharges of pollutants and charging the objects of I – III categories of the negative environmental impact. Also, legal uncertainty was identified in the development and approval of methods and techniques of accounting for the natural background in regulating permissible discharges, which entailed the current problems of establishing regulations for permissible discharges for water users. Approaches to improving the environmental legislation to address related issues are described. There is a need to harmonize the requirements for establishing standards on permissible discharges for various categories of objects of negative environmental impact in terms of a more sound definition of the lists of pollutants subject to regulation, as well as the compliance of more stringent requirements with more hazardous categories of objects. To eliminate economically and technically inaccessible requirements to the quality of effluents discharged, a legislative justification of the limiting requirements to the water quality in receiving water bodies and effluent quality is proposed.
Key words
standards for permissible discharges , provisionally permitted discharges , objects of negative environmental impact
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DOI 10.35776/MNP.2020.06.04
UDC 628.356.24
Grigor’eva Anastasiia, Abiev Rufat
The influence of the design of the mixing device on the efficiency of mass transfer during pneumo-mechanical aeration of wastewater
Summary
Aeration is the most energy-intensive process in wastewater treatment. The expenditures for air oxygen supplied for biological treatment are about 60% in the treatment cost structure. Thus, the efficiency of mass transfer and reduction of air consumption is an urgent task for the enterprises that look for improving the economic efficiency of their activities. The purpose of this work is to determine the effectiveness of a pneumo-mechanical aeration system using a turbine mixer and a new conical mixer designed by the authors, as well as to compare the efficiency of gas dispersion in pneumatic and pneumo-mechanical aeration systems. As a criterion for comparison, SOTE (Standard Oxygen Transfer Efficiency) indicator that is the main process parameter that provides for comparing the effectiveness of different aeration systems, is selected. The second efficiency criterion is SAE (Standard Aeration Efficiency) indicator, i. e. the ratio of the amount of oxygen dissolved in liquid to the amount of the electrical energy consumed. As a result of experimental studies, it was found that the conical mixer was as efficient as the turbine one in the rate of saturation of water with oxygen, while consuming much less electrical energy. With the development of a bevel wheel mixing in the «gas-liquid» system in large-sized apparatus became possible owing to the low resistance of the blades, which is especially important for aeration tanks with a small depth in the process of biological wastewater treatment under the conditions of the significant reduction in the effectiveness of the pneumatic system.
Key words
wastewater treatment , pneumo-mechanical aeration , mixing device , sulfite method , criterion of the aeration efficiency , mass transfer
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DOI 10.35776/MNP.2020.06.05
UDC 628.161.2:628.169:675.024
Chursin V. I., Panfilov E. V.
Precipitation of dyes from spent solutions using magnesium-containing agents
Summary
Spent solutions generated in the process of skin dyeing make a significant negative contribution to the pollution of the total amount of wastewater of the enterprise; hence, the need arises for their local treatment to reduce the concentration of organic dyes before discharging into the total wastewater flow. The aim of the work was to study the possible use of magnesium-containing agents for the precipitation of dyes from local wastes. The experiments were conducted with simulated solutions of acid dyes that differed in molecular structure and the number of auxochrome groups to ensure the solubility of the dye and its adsorption by the dyeing material. Dyes were precipitated using magnesium-containing agents, i. e. suspension of magnesium hydroxide and magnesium oxide (MagPro), and for comparison, aluminium sulfate. The efficiency of the precipitation of dyes from solutions was evaluated by the amount of separated precipitate and the optical density of the supernatant. The effect of the precipitation agent consumption on the efficiency of removing dyes from the solution is shown. The results of the experiment provided for establishing the optimal consumption of precipitation agents for each of the dyes used. It was found that aluminum sulfate and MagPro were equally effective with respect to the direct brown solution. The acid black dye is predominantly precipitated with aluminum sulfate, while Luganyl brown NG is precipitated only with magnesium-containing agents. To precipitate dyes from local effluents with an equal precipitate yield, the consumption of MagPro agent is 10 times less than while using aluminum sulfate. MagPro is more effective in sedimentation and discoloration of local effluents after skin dyeing at pH above 12.
Key words
settling , aluminium sulphate , absorbency , local wastes , dyes , magnesium-containing agents , magnesium hydroxide , discoloration of solutions
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DOI 10.35776/MNP.2020.06.06
UDC 628.218::628.334.6
Gudkov Aleksandr
Calculation method for determining the capacity of intermediate storage tanks in storm sewer networks (for discussion)
Summary
Целью работы является дополнение и уточнение методик, приведенных в действующей нормативно-методической базе, для инженерного расчета схем регулирования расходов в сетях дождевого водоотведения. Методом математического моделирования с применением системы компьютерной алгебры проанализированы три схемы регулирования, включающие емкости, насосы и разделительные камеры. Предложена универсальная расчетная формула определения объема регулирующего резервуара в схеме регулирования с опорожнением емкости насосами для всех типов разделительных камер. Установлены зависимости и приведены графики, показывающие влияние на величину объема резервуара коэффициента, который учитывает непостоянство расхода, отводимого разделительной камерой в коллектор. Для схемы регулирования без насоса и разделительной камеры подобрана степенная аппроксимирующая функция, позволяющая проводить расчет величины объема с приемлемой точностью, без численного интегрирования. Для двух схем регулирования с опорожнением самотеком предложены новые формулы определения объема регулирующего резервуара в широких диапазонах коэффициентов регулирования и параметров дождей. Приведены уточненные таблицы, упрощающие инженерные расчеты регулирующих резервуаров. Предложенные в работе формулы и таблицы позволяют рассчитывать емкость резервуаров для всех рекомендуемых схем регулирования расходов.
Key words
surface runoff , sewer , calculation method , separation chamber , intermediate storage tank , flow control
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DOI 10.35776/MNP.2020.06.07
UDC 628.147.2
Solov’ev Viktor
Management of the scheduled preventive maintenance of the water distribution and sewer networks
Summary
The long-term experience of Vodokanal of Novokuznetsk in operating the water distribution and sewer networks is analyzed. An optimal list of preventive maintenance measures is presented, that forms the basis of the current operation of the networks, with recommendations on the periodicity and seasonal maintenance works. The step-by-step schedule of the preventive maintenance works was developed in accordance with the specific features of the group operations of the water distribution and sewer networks: water mains, urban (well-maintained) area networks, and private sector networks. The list of preventive maintenance works is based on the principle of reducing the total costs of the enterprise for the full range of activities by forming their optimal minimum. The proposals do not provide for any increases of the staffing of the relative services of the enterprise and ensure the compliance with the requirements to the reliability and quality of the services rendered in accordance with the requirements of the applicable laws and regulations.
Key words
scheduled preventive maintenance , failure elimination , optimal arrangement of the scheduled preventive maintenance , water mains , urban area networks , private sector networks
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DOI 10.35776/MNP.2020.06.08
UDC 628.169
Kofman V. Ya.
Water sludge: utilization in the production of construction materials and agriculture Alternative coagulants (a review)
Summary
Utilization of water sludge in significant amounts can be provided by using it in the production of construction materials and in agriculture. The use of water sludge in the construction industry can result in significant savings in traditional raw materials without compromising product quality. However, the supply of water sludge to the construction industry enterprises, has not been established so far, and the instability of its composition is posed as the main reason. At the same time, the results achieved evidence significant efforts made in this area. Based on the use of water sludge, technologies have been developed for the production of cement, building mortar, concrete, brick, roofing tiles, and ceramic products. Agricultural use of water sludge is considered as a most affordable and large-scale option of its disposal. The concentration of organics and heavy metals in water sludge is quite limited, which sets it apart from wastewater sludge and allows it being classified as safe. To date, in a number of countries many years of large-scale experiments have been conducted on the use of water sludge for adjusting the concentration of soluble phosphorus in soils; binding soluble forms of arsenic and chromium, and adjusting the concentration of trace elements. A radical solution to the problem of water sludge disposal should be associated with reducing its amount generated during water purification process. In this direction, studies are being conducted on alternative coagulants, primarily of plant origin. The results achieved made it possible to carry out pilot tests of using aqueous extract of Moringa oleifera oil-tree seeds as a coagulant in the purification of surface water.
Key words
ceramics , water sludge , brick manufacture , cement , building mortar , concrete , agriculture , soil amendment , alternative coagulants of plant origin , Moringa oleifera
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