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Number 5 / 2021
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DOI 10.35776/VST.2021.05.01
UDC 628.166.094.3:66.011
Gvozdev V. A., Portnova T. M., Korchigo Tat’iana, Morozova Svetlana, Semivolos Elena, Mekhnetsov Il’ia, Koniukhov Mikhail, Stolbov Kirill
Methods of optimizing chlorammoniation processes on the basis of online water quality monitoring (experience of SUE «Vodokanal of St. Petersburg»)
Summary
Disinfection of water with chlorine, along with the filtration at water treatment facilities has been historically the oldest and therefore routine technological process. The practice of disinfection process control that has been developed at the facilities over many years is often based on not exactly justified, and sometimes on erroneous, decisions made in the past. The main reference points, as a rule, are only regulated parameters, i. e., residual chlorine concentration and microbiological indicators at the outlet of the facilities. Meanwhile, the location of the chemical injection points, initial concentrations of chemicals and the dosing rate are of key importance from the point of view of the technology efficiency, reliability and safety. Accuracy and efficiency of chemical concentration control, control of the chlorine binding efficiency in the process of water ammoniation are the decisive factors in the process automation. Traditionally and formally, production control programs are based on the laboratory methods developed back in the early twentieth century. At the same time, progress in analytical instrumentation provides for monitoring the process parameters of disinfection in real time mode. The results of pilot tests of optimizing chlorammoniation processes based on online water quality monitoring are presented. The tests were carried out at the Southern Water Treatment Plant of SUE «Vodokanal of St. Petersburg». The analysis of the laboratory methods for monitoring the concentration of active chlorine and nitrogen-containing substances from the point of view of ensuring a reliable assessment of the physicochemical processes of chlorammoniation has been carried out. An assessment of the capabilities of modern analyzers for improving the efficiency, accuracy and safety of methods for controlling the chlorammoniation process is given. Some significant events in the history of the development of water disinfection technology in Russia and in the world are given in the Introduction.
Key words
disinfection , free ammonium , chlorination by-products , chlorine demand , chemical concentration , optimal parameters and process efficiency , flow-through analyzer , online monitoring , automatic dosing system
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DOI 10.35776/VST.2021.05.02
UDC 628.35
SHVETSOV V. N., Kharkina O. V., Stepanov S. V.
Comparison of the calculation results for aeration tanks using the NII VODGEO/SamGTU and ASM2d models
Summary
Проведено сравнение результатов расчета аэротенков, реализующих процессы аэробного окисления органических соединений, нитрификации, денитрификации и удаления фосфора (химического и биологического) по двум различным математическим моделям (методикам): ВОДГЕО/СамГТУ (Самарского государственного технического уни-
The paper presents a comparison of the results of calculating aeration tanks where the processes of aerobic oxidation of organic compounds, nitrification, denitrification and phosphorus removal (chemical and biological) according to two different mathematical models (methods): VODGEO/SamGTU (Samara State Technical University) and ASM2d have been implemented. These models are theoretical and describe the processes of biological wastewater treatment using enzymatic kinetics formulas. Calculations for the same input and output data showed a high reproducibility in terms of the volumes of the process zones of aeration tanks. For the quality of effluent meeting the MPCs for fishery water bodies (option 1), the discrepancy is –0.3 and 3.3%, respectively, for the anoxid and aerobic zones. With indicators for effluent discharge into a water body of category B (option 2) for large-scale to extremely large-scale facilities, the difference in the results of calculating the volumes was 13.8 and 15.4%, respectively. While making calculations with account of the effluent quality reaching the process indicators for discharge into a water body of category G (option 3) for large-scale to extremely large-scale facilities, the discrepancy in the values of the volumes of aerobic zones was 48% owing to the expediency of ensuring stable nitrification at high loads. Therefore, option 3 according to the VODGEO/SamGTU method was actually performed for a lower sludge load and more enhanced nitrification than according to the ASM2d method (1 instead of 2 mgN–NH4/l). It is shown that the mathematical models underlying both methods, based on the fundamental equations of the enzymatic reaction, a very high reproducibility and consistency of the calculation results give grounds to assert that both of these models are, to the greatest extent known, acceptable for calculating biological treatment facilities with the removal of nitrogen and phosphorus.
Key words
biological treatment , nitrification , denitrification , activated sludge , kinetic constants , industrial and municipal wastewater , VODGEO/SamGTU and ASM2d process calculation methods , theoretical and empirical mathematical models , comparative calculation of the biological treatment facilities
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DOI 10.35776/VST.2021.05.03
UDC 628.316.12
Strelkov A. K., Stepanov S. V., Panfilova O. N., Arbuzov Aleksandr
Removing heavy metals from effluents with natural and modified clay-containing sorbents
Summary
The results of studies of the sorption of heavy metal ions by clay-containing sorbents from plating effluents are presented. The purpose of the tests carried out in a pilot plant was developing a process scheme for the removal of heavy metal ions from effluents and extraction of the spent sorbent in a precoat cartridge filter with a layer of perlite. The materials used in the tests were as follows: thermally modified sorbent based on natural material, i. e., modified clay, as well as mixed sorbent consisting of montmorillonite, peat and dolomite in a ratio of 5:4:1 without heat treatment. The studies were carried out on eight ions of heavy metals in the low concentration range typical for the effluent coming for tertiary treatment after sedimentation with pH adjustment. The main process parameters of tertiary treatment were: pH 8; the duration of the sorbent contact with the effluent was 90 min, the dose of sorbents was 1–1.6 g/l. The separation of the spent sorbent from the effluent was executed in two stages – sedimentation and filtration in a precoat cartridge filter. The addition of Aqua-AuratTM-30 coagulant with a dose of 40 mg/l as Al2O3 provided for reducing the concentration of suspended solids in the clarified effluent supplied to the precoat filters to 8 mg/l for modified clay and 15 mg/l for the mixed sorbent. The specific productivity of the alluvial layer was 23 m3/(h·m2), the specific load of the suspension on the filter surface was 850 g/m2 for modified clay, and 680 g/m2 for mixed sorbent. The estimated duration of the filtration phase of the alluvial layer while using preliminary chemical sedimentation was 4.6 and 2 h for the modified clay and mixed sorbent, respectively. The efficiency of removing heavy metal ions from effluents was provided at the level of the maximum permissible concentration for fishery water bodies.
Key words
wastewater , sorption , heavy metals , modified clay , dolomite , montmorillonite , peat , precoat filter
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DOI 10.35776/VST.2021.05.04
UDC 628.35:661.5
Kondrashev Viacheslav, Metelitsa Sergei
Stages of launching a biological treatment plant at the wastewater treatment facilities with dosing easily oxidable organic matter
Summary
Issues related to commissioning a biological treatment plant at the facilities for household and similar in composition wastewater treatment during the trial start of the treatment facilities are considered. The stages of commissioning a biological treatment plant at the wastewater treatment facilities with «inoculating» activated sludge from the operating biological treatment facilities and with dosing easily oxidable organic matter are considered in detail. The equipment configuration of the WWTP-9 produced by Germes Group is described. All stages of the biological treatment plant commissioning are considered through the example of the start-up of WWTP-9 with the use of numerous experimental data. The periods of biological treatment plant commissioning stages have been determined. The problems of adjusting the biological treatment plant and the ways of their elimination to achieve the required result are presented. The technology used at the WWT facilities provides for the effluent quality that meets the requirements for the discharge into a water body of commercial fishing importance.
чения.
Key words
wastewater , biological treatment , mechanical treatment , aftertreatment , commissioning , biological treatment plant
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DOI 10.35776/VST.2021.05.05
UDC 622.794.25
Kotrelev V. M., Polosina Tat’iana, Novikov Gleb, Papush Pavel
Alfa Laval’s latest developments in sludge dewatering with decanter centrifuges
Summary
The innovative technologic solutions developed by Alfa Laval Company and implemented in Aldec G3 decanter centrifuge are considered. Alfa Laval Company produces two types of advanced decanter centrifuges for wastewater sludge dewatering (altogether there are more than 12 types of centrifuges for use in various fields: from the food industry and biopharmaceuticals to dewatering oil sludge or tailings of the mining industry). The use of Aldec G3 decanter centrifuge provides for the maximum reduction in the total cost of wastewater sludge dewatering. Described are the types of repair work for decanter centrifuges carried out in Alfa Laval, the only ISO-certified service center in Russia.
Key words
power saving , wastewater treatment , decanter , sludge dewatering , decanter centrifuge , equipment upgrade
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DOI 10.35776/VST.2021.05.06
UDC 628.356.1:621.61
Ovseichuk B. V., Guseinova Elena, Florian Adam
On the operation of blowers controlled by mechanical blades
under extreme conditions
Summary
Reducing energy costs for air supply to aeration systems of the treatment facilities by using adjustable air blowers is an urgent task. A comprehensive analysis of operating single-stage centrifugal air blowers controlled by mechanical rotating blades under low ambient temperatures typical for Russia is presented. In the process of monitoring, the parameters of the air blowers were monitored (air temperature at the compressor inlet, excess pressure at the compressor outlet, vibration level, lubricating oil temperature, temperature of the impeller shaft bearings, input current consumed of the electric drive motor).
Key words
adjustable air blower , excess pressure , air temperature reduction , measurement diagram , parameters of the air blower operation , input current of the electric motor , isentropic performance factor , rotating blade , centrifugal compressor
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DOI 10.35776/VST.2021.05.07
UDC 628.218:628.144
Chupin R. V., Morozova Svetlana
The use of road transport in the systems of group water supply
and wastewater disposal
Summary
Due to the uneven distribution of water resources across the territory of Russia, many communities and even cities lack own water supply sources and water bodies where effluents could be discharge into. To address this problem, group and district water supply and wastewater disposal systems are designed, built and developed. The length of such systems is hundreds and even thousands of kilometers. Significant financial resources are required annually for their construction and operation. Therefore, the issues of the choice of routes, composition of the structures and especially methods of transporting water and wastewater, justification of locating water intakes and treatment facilities are relevant and require special attention and technical and economic analysis of design options. A method is proposed for the comprehensive optimization of the parameters of water supply and wastewater disposal systems that will provide for determining the best ways of transporting water and wastewater (by pipelines or in road-tankers), location of water intakes, water supply and wastewater treatment facilities, optimal pipeline routes and auto routes between these structures and customers.
Key words
system of group water supply and wastewater disposal , method of excess design layouts , method of finding the maximum flow of the minimum cost , road and pipeline transport
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