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Number 12 / 2020
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Literature lists to articles (doc)
Index of the Articles (pdf), Published in the Water Supply and Sanitary Technique Magazine in 2020г.
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UDC 628.167.069.84
Fedotov R. V., Shchukin S. A., Kniazeva Natal’ia, Onkaev Viktor
Study and engineering and economic comparison of chemical methods of softening the Bolshoi Kinel River water
Summary
Softening water for domestic water supply can be carried out by different methods including the addition of alkaline agents into water. Experimental studies of the use of lime-soda and caustic soda methods for softening the Bolshoi Kinel River water that is the source of drinking water supply for the city of Otradny, Samara Region, have been carried out by the employees of EKOFES SPE LLC in the laboratory and working environment. A diagram of a laboratory setup has been developed consisting of a mixer with aeration and an air separator, a vertical sedimentation tank with laminar modules, and a rapid filter. Experimental studies on the effect of chemical doses on the values of residual water hardness and total dissolved solids have been carried out. It has been established that the caustic soda method provides for efficient water softening, however results in an increase in the total dissolved solids, thus limiting the area of application. The results obtained in the study of the lime-soda method allow to conclude that the technology is advantageous owing to the elimination of extra water salinization and to recommend it for softening the water of the Bolshoi Kinel River. The engineering and economic calculation of the cost of 1 m3 of processed water depending on the softening method is presented.
Key words
drinking water supply , chemical softening , water hardness , lime-soda softening method , caustic soda softening method
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UDC 621.929
Grigor’eva Anastasiia, Abiev Rufat
Study of the suspending process with the use of a conical mixer through the example of the process of sulfuric acid neutralization at Sviatogor JSC
Summary
The process of suspending solid particles in a liquid by means of mechanical mixing is considered. A technique for the selection of mixing devices with account of the geometry of the mixer has been developed and described. The methodology is based on the semi-empirical Zwietering model, supplemented in the course of additional studies by Ayranchi and Kresta. Various modes of the suspending process have been studied. On the basis of theoretical relationships, a conical mixer with a special blade geometry was developed and tested in laboratory conditions resulting in a highly efficient suspending process. The empirical suspending coefficient of Zwietering and Ayranchi–Kresta was calculated resulting in the possibility to calculate the required parameters of the mixer on a scale of industrial reactors. The efficiency of the new mixing device was proved during industrial tests in a chemical reactor for quenching sulfuric acid with lime milk. Owing to the use of a conical mixer the reaction rate was reduced from 60 to 38 minutes with a 40% reduction in electricity consumption. It is proved that a sufficient condition for the enhancement of the neutralization process will be eliminating the sedimentation of the suspended sludge to the bottom of the reactor, i.e. the suspending process in the bottom part shall be enhanced.
Key words
sulfuric acid , conical mixer , mixing , suspending , neutralization
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UDC 628.54:676
Feofanov Yu. A., Tarasenkov Viktor, Cherniat’ev Anatolii
Specific features of paper mill wastewater treatment
Summary
The results of the operation of local and all-factory wastewater treatment plants of a separately located paper mill using waste paper and cellulose as raw materials are considered and analyzed. The following characteristic features of the factory wastewater are indicated: significant fluctuations in flow rate and composition, high concentration of organic matter, elevated temperature, etc. The conditions for the effective operation of the local treatment facilities, including chemical treatment and two-stage pressure flotation when using waste paper and cellulose as raw materials, are noted. The unit costs and amount of effluent pollution discharged after local treatment have been determined. The data on the efficiency of the all-factory biological treatment facilities including a moving-bed bioreactor and aeration tanks, are presented. Dependencies of the main process parameters of the facilities have been obtained that provide for predicting the treatment efficiency. Measures are proposed to improve the operation of local facilities and biological wastewater treatment facilities of a paper mill.
Key words
reagent treatment , wastewater , bioreactor , aeration tank , pressure flotation , local treatment facilities
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UDC 579.695+579.8
Gogina Elena, Bazhenov V. I., Sokolova Kseniia
Bacterial composition of activated sludge: identification and visualization
Summary
The objective of this work is to describe the capabilities of a method for visualizing activated sludge bacteria based on the information from an Internet resource for developing textbooks and/or manuals. Advanced methods of microscopy of the bacterial community are considered: optical light, scanning electron (SEM), transmission electron (TEM), confocal (CLSM), fluorescence hybridization in situ (FISH), new generation sequencing (NGS). On the basis of the methods presented, examples of bacterial flocculation of activated sludge with extracellular and reserve biopolymers are given. According to the highest citation frequency in professional reference books and literature, a sample of the most typical bacteria from the composition of floccules of activated sludge was compiled. Examples of visualization of four bacteria by SEM, TEM, KLSM, FISH methods are given: Bacillus subtilis (gram-positive, spore-forming, optionally aerobic), Nitrospira defluvii (gram-negative, aerobic, chemolithotrophic, nitrite-oxidizing), Candidatus «Accumulibacter phosphatis» (gram-negative, phosphate-accumulating), Candidatus «Microthrix parvicella» (gram-positive, filamentous, actinomycete). To date, the Internet resource contains a sufficient amount of reliable data on the visualization of activated sludge bacteria, their functionality and properties related to the key processes of biological treatment, classification or taxonomy, as well as on the methods of their microscopic study. The implementation of the capabilities for identifying the bacterial composition of activated sludge and the quantitative ratio of heterotrophic, autotrophic and phosphate-accumulating biomasses provides for setting and/or calibrating models of ASM series (for example, in GPS-X, BioWin, etc. software environment).
Key words
biological treatment , activated sludge , phosphate accumulating bacteria , filamentous bacteria , bacterial composition , extracellular biopolymers , visualization , identification , filamentous bacteria , autotrophic bacteria
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UDC 621.646
Mikhailov V. V., Kurganov Iu. A., Goncharov Sergei
Analysis of regulatory requirements for shut-off and control valves for drinking water supply networks and world practice
Summary
The problem of the absence in Russia of a specialized industry for the production of materials and equipment for the water supply and wastewater utilities is described. The requirements of domestic and international regulatory documents for shut-off and control valves for drinking water supply, including the methods of control and testing of valves in production, are stated and analyzed. The experience of operating shut-off and control valves in the drinking water distribution networks, including directly buried ones, at the facilities of SUE «Vodokanal of St. Petersburg» is presented. Particular attention is paid to the requirements of SUE «Vodokanal of St. Petersburg» to the shut-off and control valves installed in the municipal water distribution networks. Developing a system of regulatory documents directly for the water and wastewater utilities, and in particular for drinking water supply products, will provide for systematizing the requirements to the product control and testing systems, improving the quality and increasing the life of the utilities.
Key words
water supply-sewerage services , shut-off and control valves , drinking water supply , acceptance test
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UDC 628.1/.2:621.65
Yepifanov S. P., Baranchikova N. I., Kurtin A. V.
Mathematical modeling of the joint operation of pumping units including frequency regulated ones
Summary
The use of pumping units with variable speed drives in order to save energy and provide for effective operating modes in water supply and sanitation systems, sometimes without sufficient justification, does not always furnish the desired result. One of the reasons is the lack of a simple mathematical model describing the flow distribution in the process pipelines of pumping stations with account of all the limitations of the operating mode parameters while using variable speed drives in some or all pumping units. The flow distribution task itself should be represented in the form of an optimization problem where the objective function can be the total energy input of all the operating pumping units. Such an optimization model provides for describing the operating modes of both paralleled and compound pumps. Once the electricity costs for all significant modes throughout the year have been determined and compared with the existing modes without the use of variable speed drives, drawing a reasonable conclusion about the applicability of variable speed drives in one or several pumping units becomes possible. The proposed model provides for arranging both effective and technologically acceptable modes. Based on the obtained results of calculating the optimization task for several modes, it is possible to construct approximating functions of the total flow of the pumping station from the head losses in throttling devices and use them in case of the flow meter lack or failure.
Key words
pressure , frequency converter , hydraulic head , centrifugal pump , pumping unit , flow distribution task , optimization task , energy input , parallel and serial operation of pumps
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UDC 628.24:69.059
LOMBAS S. V., Zhitenev A. I., Perminov N. A.
Geotechnical support of the zero-defect life cycle of unique sewage pumping stations in complex engineering and geological environments
Summary
For the sustainable development of megalopolises, the sustainable operation of the urban underground engineering infrastructure has been one of the prime factors where the main sewage pumping stations are unique elements. On the basis of the study of extensive pilot and experimental materials, the specific features of the operation of long-term operating head sewage pumping stations built by the method of large-sized coffers in a complex soil environment are analyzed. The results of the long-term monitoring of the technical state of structures are given, the classification of defects and the dynamics of their development are given. Based on the results of modeling the joint operation of the systems «lowerable shell of the pumping station – the inclosing geomass» and results of the experiments, the actual bearing capacity of the structure is predicted, as also preventive geotechnical measures are proposed to ensure the trouble-free life cycle of the underground structure at the pilot wastewater facilities. Geotechnological methods for protecting pumping stations with monitoring support have been developed. A unique experience of practical application of the developed methods at the stages of the life cycle of the head sewage pumping stations at the facilities of the SUE «Vodokanal of St. Petersburg», including design, construction and operation, is presented.
Key words
monitoring , complicated ground conditions , geotechnical protection measures , unique underground wastewater structures , large-sized coffer
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