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UDC 628.35:661.5

Stepanov S. V.

Specific features of designing oil refinery wastewater biological treatment facilities

Summary

Oil refinery wastewater is characterized by the presence of organics resistant to oxidation and practically total absence of phosphorus. The procedure of designing oil-containing wastewater biological treatment with nitrification-denitrification is used both for aeration tanks and membrane bioreactors. Designing is carried out with the use of kinetic relationships for all the regulated pollutants. During the experiments kinetic constants and coefficients of nitrification and denitrification processes, oxidation of organic substances (as BOD and COD), oil products, phenols and synthetic surfactants for waste­water of a number of oil refineries were obtained. Calculations algorithm includes the following stages: determining initial data – pollutant concentrations and wastewater flow rates; choosing the process flow scheme of the treatment facilities; calculating specific rate of biological treatment process on the basis of kinetic constants and coefficients; calculating activated sludge growth, nitrogen and phosphorus losses in the process of assimilation; estimating the retention time for oxidation of separate ingredients of pollutants and denitrification; determining the maximum aerobic process time in respect to the limiting component and treatment level in respect to other ingredients; calculating the required air consumption; checking the necessity of dosing phosphorus compounds for nutrient makeup. To improve the denitrification efficiency the configuration of the facilities was enlarged with a mixed liquor deaerator. The process design of a membrane bioreactor differs from the design of aeration tanks with nitrification-denitrification by correction of specific oxidation rate with account of the obtained kinetic constants and coefficient of inhibition with metabolism products at higher concentrations of activated sludge in the bioreactor. The experimental results allowed supplementing the procedure of designing wastewater biological treatment facilities with nitrification-denitrification developed by NII VODGEO.

Key words

wastewater , biological treatment , nitrification , activated sludge , membrane bioreactor , denitrification , oil refinery , kinetic constant

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UDC 628.35:62-278:725.42

Kharkina O. V., Strelkov A. K., Stepanov S. V., Stashok Yu. E., Sven Baumgarten, Josef Sheren

Treatment of Syzran oil refinery industrial wastewater in membrane bioreactor

Summary

The results of investigating biomembrane technology of Syzran oil refinery industrial wastewater treatment are presented. The kinetic parameters of nitrification-denitrification processes are determined. It was demonstrated that biomembrane technology provided for the intensification of these processes alongside with meeting the requirements set to the effluent quality in relation to nitrogen compounds whether with or without addition of biodegradable substrate. The experimental data proved the possibility of either using the effluent for industrial closed-loop water system makeup after partial desalination or (and) discharging it into surface water bodies after polishing with sorption.

Key words

nitrification , oil products , activated sludge , membrane bioreactor , denitrification

DOI 10.35776/VST.2022.02.05
UDC 628.32:22.765

Semin M. M., Tokarev Nikolai, Iavtushenko Marina, Lobanov Fedor, Chukalina Tat’iana, Plekhanov A. V.

Use of a chemical regulator at the wastewater treatment facilities operated by MUE Vodokanal of Podolsk

Summary

Possible use of natural minerals based on calcium carbonate (monocalcite) to correct pH (carbonate-bicarbonate equilibrium) in order to improve the treatment effect of activated sludge bacteria in the aeration tank and the sedimentation properties of activated sludge in the secondary settling tank is considered. The sedimentation properties of activated sludge are corrected because of the interaction between functional oxygen-bearing substrata of activated sludge flocculation bacteria and calcium ions. As a result, firm, rapidly settling flocs are formed and, consequently, the value of the sludge index decreases compared to the technological line and settling line operating in the regular mode. It is recommended to use a chemical regulator to normalize the operation of the aeration tank in winter (possible bioflotation), spring and autumn periods at high hydraulic loads.

Key words

calcium carbonate , sludge index , aeration tank , secondary settling tank , activated sludge , bioflotation

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UDC 628.356.1

Meshengisser Yu. M.

The past and future of the domestic aerator engineering (on the occasion of the 25th anniversary of the first RF Patent «Tube aerator»)

Summary

The stages of development of the domestic production and use of aeration systems in wastewater treatment – from traditional perforated pipes to high efficient aeration systems are described. The drawbacks and advantages of aerators, their applicability under certain conditions are designated. In the years ahead the development of  not just aerators is planned but of aeration systems that include the entire equipment set for saturating water with oxygen: regulated air blowers, delivering and distributing pipelines with shutoff and control valves, comprehensive automated air supply control systems, aerators, systems of quick-detachable fittings and other elements that provide for optimal supplying air to the aeration tanks and if necessary for easily changing the system configuration in the process of retechnologisation of the treatment facilities.

Key words

biological treatment , activated sludge , aerator , aeration system , air-lift effect

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UDC 628.35

SHVETSOV V. N., MOROZOVA K. M., Stepanov S. V.

Designing facilities for municipal and industrial wastewater biological treatment in aeration tanks with nutrients removal

Summary

Biological treatment facilities are the basic facilities for the purification of domestic, municipal and industrial wastewater of most of the industries (chemical, petrochemical, oil refining, food, textile, consumer goods, coke-chemical industries, agriculture etc.). However until now there has been no scientifically-grounded method of designing wastewater biological treatment facilities with nitrogen and phosphorus removal in the Russian Federation. Many years of extensive research carried out by NII VODGEO and «Water Supply and Wastewater Disposal» chair of the Samara State Technical University at the laboratory and pilot plants, at the operating facilities with processing data bulks provided for developing an adequate method of designing aeration tanks with nutrients removal. The presented method is a supplement of the method of process design of biological treatment facilities stated in SNiP 2.04.03-85 with regard to designing aeration tanks with nitri-denitrification and biological phosphorus removal; and provides for the calculations of upgrade and new construction of the facilities for biological treatment of municipal, domestic and industrial wastewater. Behind the process design is the concept of the process description with enzyme kinetics equations. The method includes the following stages: substantiation of the relevant basic data on the flow rates and qualitative composition of wastewater; determination of the process flow scheme and burden balance calculation of all the critical pollution components; determination of the kinetic constants and coefficients of enzyme kinetics equations of the transformation of each basic pollution component (BOD, nitrogen compounds, phosphorus etc.) and activated sludge growth by the statistical analysis of the operation data and chemico-analytical analysis of wastewater samples of the operating treatment facilities, by experimental data or on the basis of the available analogies; calculation of the volume of all the elements of the facilities with determination of the limitative component and treatment level in relation to other pollutants; final correction of the vo­lumes and parameters of all the process zones with account of the requirements to the level of treatment in relation to all the dictating pollution components. An example of the calculation is set. It is noted that the computation algorithm and formulas included into the method provide for designing any complicated process flow schemes with nitrogen and phosphorus removal applied both to municipal and industrial wastewater. The method provides for calculating not only the rate of removing BOD and nitrogen compounds but also other certain pollution components (oil products, detergents, fats etc.) offering additional opportunities of the wastewater biological treatment method. The method is especially useful in designing industrial wastewater biological treatment facilities because most of the foreign methods are mainly focused on the purification of domestic and municipal wastewater to the concentrations adopted in those countries. The method is developed on the principle of essential sufficiency; however is contains 70 design parameters and 28 formulas and equations. Accordingly the calculations are performed in Microsoft Office Excel which makes it possible for users even with middle software skills. Herewith it is possible to perform calculations straight for several options interactively and/or upgrade the treatment facilities in the process of their operation.

key words

biological treatment , nitrification , denitrification , nitrogen , phosphorous , activated sludge , kinetic constants , process design method , industrial and municipal wastewater

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UDC 628.35:661.5

SHVETSOV V. N., MOROZOVA K. M.

Procedure of designing wastewater biological treatment facilities
with nutrients removal

Summary

The procedure of designing wastewater biological treatment facilities with nitrification-denitrification is presented. Biological treatment facilities shall be designed on the basis of experimentally determined kinetic constants, nitrification and denitrification process factors, and for every limiting value depending on the requirements to the quality of treatment. Kinetic constants and factors required for designing municipal wastewater treatment facilities are given. Design algorithm is set out including the following stages: substantiation of the initial data on flow rates and qualitative wastewater composition according to the required level of reliability (more than 85–90% probability); selection of the process flow scheme – number of steps and(or) stages, operation procedure and lay out; determination of kinetic constants of equations of enzyme kinetics of every basic pollution component transformation from experimental data or from the available data base; preliminary calculation of excess activated sludge volume and adjustment of nitrogen and phosphorus mass balance; determination of limiting pollution component that needs maximum time to be oxidized; calculation of the facility capacity by limiting component with determination of the treatment level for other pollution components. The results of the long-term experimental studies of nitrification-denitrification processes with different types of municipal and industrial wastewater provide for supplementing the method of aeration tank design specified in SNiP 2.04.03-85 with formulae and data for design and optimization of aeration tank operation with nitrogen and phosphorus removal.

Key words

wastewater , biological treatment , nitrification , activated sludge , kinetic constants , denitrification

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UDC 628.35:661.5/.63.001.2

SHVETSOV V. N., MOROZOVA K. M., Domnin K. V., Arkhipova Elena

Designing nitrification-denitrification retrofit at the biological treatment facilities

Summary

The results of studies carried out at the Khabarovsk wastewater treatment facilities are presented. The developed process flow sheet of wastewater biological treatment included nitrification-denitrification processes to eliminate nitrogen compounds according to the set standards. The process flow sheet provided for retrofitting dephosphatation zone to ensure maximum level of phosphorus removal at the biological treatment stage in order to reduce chemical consumption at the subsequent treatment stages. The process design of the biological treatment facilities was carried out.

Key words

treatment facilities , wastewater , nitrification , dephosphatization , activated sludge , denitrification

UDC 628.35
DOI 10.35776/VST.2023.05.06

Нездойминов В. И., Рожков В. С., Zavorotnyi Dmitrii, Chernyshev Valentin, Vasil’eva Iuliia

Municipal wastewater treatment systems based on airlift bioreactors

Summary

The aspects of municipal wastewater biological treatment with activated sludge with the cultivation of phosphorus-accumulating microorganisms and simultaneous nitri-denitrification are considered. Improved schemes for the biological removal of organic pollutants, nitrogen and phosphorus compounds based on airlift bioreactors (BOSEB technology) are presented. The main results of pilot studies are submitted that acknowledge the effectiveness of the proposed technology in the treatment of municipal wastewater. The features of the operation of an activated sludge blanket type tank built into an airlift bioreactor have been studied. It has been experimentally established that during the operation of the sludge blanket tank, either the presence or absence of phosphorus-accumulating microorganisms in the activated sludge biocenosis does not affect the efficiency of removing suspended solids. Empirical dependences have been obtained for the calculation of the facilities for sludge separation in a self-renewing activated sludge blanket. It has been established that the main controlled parameter of the biological treatment process is the dissolved oxygen concentration in the saturation zone (upper part of the airlift bioreactor), which should be in the range of 1.6–2.4 g/m³. An economic evaluation of the effectiveness of the proposed solutions was carried out in comparison with the SBR process. The advantages of the BOSEB technology are presented in relation to the schemes of enhanced biological removal of phosphorus accepted in the Russian Federation and abroad.

Key words

biological treatment , activated sludge , airlift bioreactor , flock blanket clarification

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UDC 628.35

Dubovik Ol’ga, Markevich R. M., Antonov K. V.

Improvement of biological removal of nitrogen and phosphorus compounds from wastewater under the conditions of cascade denitrification

Summary

In view of ever toughening requirements to wastewater treatment the optimization and intensification of wastewater treatment facilities operation become priority areas. The flow process scheme of wastewater biological treatment at the Minsk Wastewater Treatment Plant is represented by traditional aeration tanks and aeration tanks with organized cascade denitrification scheme. The main component of this scheme is the lack of inner recycle and possibility of dispersed inflow of clarified wastewater over the aeration tank zones. This provides for the presence of easily oxidizable organic substances in every anoxic zone. In view of building-up of pollutants in incoming wastewater and toughening the requirements to their removal the intensification of the biological stage has been an important aspect of the treatment facilities operation. The research objective was the scheme of cascade denitrification at the operating treatment facilities for the optimization of which different options of clarified wastewater distribution over the aeration tank zones were used. Wastewater entering the cascade denitrification is characterized by insufficient quantity of organic substances because a significant amount of industrial wastes. To increase the amount of organic substances it was decided to take out of service the primary settling tank and to reduce the frequency of sludge removal. The chosen optimal distribution of clarified wastewater over the aeration tank zones and increase of organic loading the efficiency of phosphate removal increased from 60 to 70%; and that of nitrogen removal – from 61 to 67%.

Key words

wastewater , biological treatment , nitrification , activated sludge , nutrients removal , cascade denitrification

DOI 10.35776/VST.2021.10.03
UDC 628.35:615.076

Dubovik Ol’ga, Markevich R. M., Gavrilovich Ekaterina, Grebenchikova Irina, Ivanovich Vadim

Improving the hydrobiological analysis of activated sludge
at the Minsk wastewater treatment facilities

Summary

Based on the accumulated experience in operating the Minsk Wastewater Treatment Facilities and a review of information sources, a scheme for the hydrobiological analysis of activated sludge was determined, and a form for recording the results of the analysis was provided. For the quantitative account of filamentous microorganisms, an original five-point system was developed. Based on the literature data analysis, favorable conditions for the mass growth of filamentous microorganisms found in activated sludge were determined. Over a long period of time, including different seasons of the year, the improved methodology was tested for monitoring the state of the sludge suspension at two sites of the treatment facilities: traditional four-line continuous-flow aeration tanks at the first site and bioreactors with cascade denitrification at the second site. The species of filamentous microorganisms, permanently living in wastewater treatment structures, have been identified, and the dominant species have been determined. The results of the analysis of filamentous forms and sedimentation characteristics of activated sludge are compared. Conclusions were made about the features of the biocenosis in the aeration tanks at the first site and in the bioreactors at the second site; about the identity of the species composition of the filamentous bacteria communities, the effect of the wastewater composition and treatment conditions (sludge load, occurrence of zones with different levels of aeration) on the properties of the sludge suspension.

Key words

wastewater treatment , sludge index , activated sludge , active sludge dosage , hydrobiological analysis , filamentous form of microorganisms , point-based system

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UDC 628.336

Koulakov A. A., Terekhova E. M., Kutsevol M. A.

Improvement of municipal wastewater sludge treatment methods

Summary

The introduction of the process schemes of removing nitrogen and phosphorus from wastewater demands a customized approach to handling the generated sludge. Permanent residence of sludge during thickening in anoxic conditions results in its septicity, deterioration of dewatering properties and phosphorus yield into supernatant. The results of the study of possible enhancement of municipal wastewater sludge thickening processes through the example of the Vologda wastewater treatment facilities that use nitrification-denitrification and biological dephosphorization in wastewater treatment are presented. During sludge dewatering in belt filter presses two return flows are generated – filtrate and washwater. Filtrate contains residual flocculant that can be reused. It was found that adding 10–15% filtrate from the dewatering facilities to the sludge during thickening resulted in increasing the thickening rate within first 30 minutes of the process, in particular; this fact provides for almost double reduction of the sludge amount. It is noted that 3 hours preaeration of sludge during thickening reduces the time of thickening by increasing the settling rate from 0.8 to 1.2–1.4 mm/min. A process flow scheme of sludge processing that includes two-stage thickening with preaeration and filtrate dosing and subsequent mechanical dewatering has been developed. Combining preaeration and filtrate dosing provides for reducing the sludge thickening time to 3–6 hours; improving its dewatering properties and reducing the dosage of flocculant during dewatering.

Key words

filtrate , activated sludge , compaction , wastewater sludges , dephosphatization , preaeration

DOI 10.35776/VST.2021.07.03
УДК 628.35

Kharkina O. V., Iskalieva Karina, Malich Ekaterina

Comparison of aeration tank calculations using ASM2d and ATV models

Summary

A comparison is made of the results of calculating aeration tanks by ATV model (Standard ATV-DVWK-A131 E «Dimension of Single-Stage Activated Sludge Plants 2000»), that is a stochastic «table» model, and by ASM2d model, that is referred to as theoretical and describes, unlike ATV, biological wastewater treatment processes using enzymatic kinetics formulas. Calculations are performed for the same input data. The calculation results show essentially limited use of ATV model; this model, as originally given in the description of this model by the designers, provides for calculating aeration tanks only for a single value of the effluent quality in terms of ammonia nitrogen as 1 mg/l and does not provide for calculating aeration tanks in terms of nitrites. Moreover, the comparison of ATV and ASM2d show that achieving the specified quality of effluent in terms of ammonia nitrogen as 1 mg/l is possible only at specific values of the kinetic constants determined by the authors in this article; whereas, any change in at least one kinetic parameter of the wastewater results in an increase in the required aerobic age of activated sludge and, as a consequence, in the calculated volume of the aerobic zone by tens of percent, which proves the risk of not achieving the required effluent quality while using ATV model even for ammonium nitrogen concentration of 1 mg/l. Taking into account the fact that ATV Method does not provide for calculating aeration tanks for the effluent quality in terms of nitrites, the results of our calculation show that the aerobic age of activated sludge of 4.05 days for a temperature of 17 ºС proposed in ATV will make it possible to achieve the effluent quality in terms of nitrite nitrogen, 0.35–0.52 mg/l N–NO2, proving the unavailability of ATV, if the requirements to the effluent quality in terms of nitrites are specified. The authors, on the basis of the calculations, make conclusions about the risk of failure to achieve the effluent quality in terms of ammonia nitrogen as well as 1 mg/l while using ATV, because ATV is a stochastic model, that is, all dependencies presented in this method have been determined for the specific operating conditions. Moreover, as specified in the ATV description, this method, even in limited conditions, is applicable strictly for urban wastewater. The calculations show that if there are requirements for the effluent quality in terms of nitrites, regardless of the required concentration value of nitrites, the ATV method is absolutely not suitable, while ASM2d, taking into account the fact that it is based on the formulas of enzymatic kinetics, provides for calculating aeration tanks for any required effluent quality in terms of both ammonium nitrogen and nitrite nitrogen and is applicable for any type of wastewater.

Key words

biological treatment , nitrification , activated sludge , kinetic constants , industrial and municipal wastewater , comparative calculation of the biological treatment facilities , ATV and ASM2d process calculation methods , aerobic age of activated sludge , theoretical and stochastic models

DOI 10.35776/VST.2022.05.03
UDC 628.35

Kharkina O. V.

Comparison of the results of calculating aeration tanks according to the method of Danilovich–Epov and ASM2d model (part 1)

Summary

The analysis of the method proposed by D. A. Danilovich and A. N. Epov for calculating aeration tanks that implement nitrogen and phosphorus removal technologies is carried out. A comparison of the results of calculations by this method and ASM2d method is given. It is shown that, in contrast to the ASM2d method that refers to theoretical models and describes the processes of biological wastewater treatment using the formulas of enzyme kinetics, the method under consideration is, in essence, an empirical calculation that contains constants that are invariable and, for the most part, not having the physical meaning. Since empirical models make a connection between the parameters obtained on the basis of the experimental data of a particular object under strictly limited conditions, these models can only be applied if all the parameters of another object exactly match the data of the object the proposed model was compiled for. Accordingly, using any empiric models, including the method under consideration, at the facilities that were not the objects for the compilation of these empiric models, leads to the risk of obtaining incorrect calculation results. Based on the performed calculations, the risks and constraints of using the method proposed by Danilovich and Epov for the calculation of biological treatment facilities are shown. In the first part of the paper, a design analysis was carried out to determine the values of the aerobic age of activated sludge that were the basic values for calculating the volume of aerobic zones of aeration tanks.

Key words

wastewater , biological treatment , nitrification , denitrification , activated sludge , kinetic constants , theoretical and empirical mathematical models , comparative calculation of the biological treatment facilities , ASM2d

DOI 10.35776/VST.2022.11.03
UDC 628.35

Kharkina O. V.

Comparison of the results of calculating aeration tanks according to the method of Danilovich–Epov and ASM2d model
(рart 2)

Summary

The analysis of the method for calculating aeration tanks proposed by D. A. Danilovich and A. N. Epov, based on the German ATV method, is continued. Due to certain limitations of the empirical ATV methodology developed on the basis of the data on the wastewater the authors were able to study, the ATV methodology cannot be applied anywhere except the treatment facilities where those studies were carried out. The Methodology has been compared with ASM2d model (a matrix of enzyme kinetics equations describing the growth rates of microorganisms and the rates of the corresponding biochemical processes), as well as with the NII VODGEO/SamGTU method that is a completely theoretical model, and the calculation formulas being enzyme kinetics equations. Calculations of aeration tanks according to the formulas of enzyme kinetics were laid down in SNiP «Sewerage. External Networks and Structures» in 1974; whereas in SNiP 1984, the calculation was given in the form of a proven methodology for biological treatment facilities for the oxidation of organic compounds. The empirical approach proposed in the Methodology opens not only a technological question about the scope of its application, but also the question of its expediency in general. The use of empirical approaches, to which the Methodology belongs, formally connects the inherent parameters in the form of invariable coefficients and empirical dependencies obtained experimentally in a narrow range of parameters and conditions of a particular object bringing the risks of significant errors. It is shown that the Methodology for municipal wastewater provides for underestimated volumes of aeration tanks by tens of percent compared with the results of calculations using the theoretical methods ASM2d and VODGEO/SamGTU developed by V. N. Shvetsov, S. V. Stepanov, K. M. Morozova that describe wastewater treatment processes using enzyme kinetics formulas. Herewith, it is shown that ASM2d and the VODGEO/SamGTU methodology give a high convergence of the results within differences of less than 10% which allows to speak about the robustness of the ASM2d model and the VODGEO/SamGTU methodology, and the limitations of the Method that can be used only for rough estimates.

Key words

wastewater , biological treatment , nitrification , denitrification , activated sludge , kinetic constants , theoretical and empirical mathematical models , ASM2d , NII VODGEO/SamGTU methodology , enzyme kinetics equations , comparative calculation

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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UDC 628.35:661.5

Gogina Elena, Gul’shin I. A.

Nitrogen removal in a circulation oxidation ditch model
under the conditions of lowered concentration of organics in wastewater

Summary

The summarized results of the third stage of an integrated study of energy efficient processes of wastewater treatment in circulation oxidation ditches are presented. The experiment was carried out in a laboratory model of a circulation oxidation ditch with horizontal directional flow of mixed liquor. The impact of low concentration of dissolved oxygen in the bioreactor volume (at 0.5 mg/l level) and low concentration of organic pollutants in the incoming model wastewater on the treatment efficiency and biomass stabi­lity was studied. The highest efficiency of total nitrogen removal was reached at the specific organics load on activated sludge (BOD) R = 0.07 g/(g∙day), average dissolved oxygen concentration 0.5 mg/l and 7.5 hours aeration time. At that the concentration of ammonium nitrogen in the effluent was about 0.6 mg/l; the concentration of nitrate nitrogen was 9.6 mg/l. The operation of the bioreactor at lowered dissolved oxygen concentrations resulted in partial biomass bulking. The sedimentation properties of activated sludge changed; however stayed at satisfactory level.

Key words

wastewater , nitrification , energy efficiency , activated sludge , denitrification , circulation oxidation ditch , biological removal of nitrogen

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UDC 628.1/.2:543.31

Egorova Yu. A., Bykova P. G., Kichigin V. I., Nesterenko O. I., Strelkova T. A.

Ecoanalytical control and monitoring of the water quality
in Samara municipality

Summary

In Samara municipality the industrial control of natural and drinking water quality is carried out by an accredited water quality testing center. The control is executed according to the program developed by «Samarskie Kommunal’nye Sistemy» LLC and approved by the Samara Area Department of the Federal Service for Supervision of Consumers Protection and Welfare. The control is performed at all the stages of water treatment beginning from the water source to water posts in the distribution network. Monitoring the water conditions in the surface water source provides for controlling the treatment facilities operating mode and selecting the required chemical dosages at every stage of the treatment process. Industrial quality control of the wastewater coming to the municipal treatment facilities and of the effluent is carried out by a chemical and bacteriological accredited testing laboratory at every process unit from the recei­ving chamber to the discharge to the Saratov water reservoir (before the discharge the effluent is biologically tested for acute toxicity). Sludge generated in the process of wastewater treatment is tested at every stage for physical, chemical microbiological, parasitological, toxicological and radiological parameters. The efficiency of the biological treatment facilities is evaluated basing on the results of hyd­robiological analysis of activated sludge. The laboratory facilities and continuous renovation of the basic infrastructure are described. Special attention is paid to the laboratory staff development and achievements.

Key words

biological treatment , monitoring , water treatment , activated sludge , permanganate oxidizability , water and effluent quality control , ecoanalytical control

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UDC 628.336.1:54:57

Shchetinin A. I.

Elemental Composition of Activated Sludge

Summary

A review of literary data on elemental composition of activated sludge components generated in the course of wastewater biological treatment is presented. Empiric formulas of activated sludge organic matter, organic matter of different microorganisms, RNA and DNA, carbohydrates, fats, fulvic acids and humic acids are considered. On the basis of literary data on seven cellular components for Escherichia coli cells the empiric formula has been obtained; this formula is proposed for biomasses of all microorganisms of activated sludge. A ratio ThOD : VSS = 1,42 coinciding with the known values; for cellular substance COD : N : P = 50 : 5 : 1, which is close to the known BCOD : N : P = 100 : 5 : 1. for the initial substrate is typical for this elemental composition. Components described make it possible to determine the elemental composition of extracellular substances of activated sludge.

Key words

microorganisms , activated sludge , wastewater biological treatment , elemental composition , proteins , nucleic acids

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UDC 628.356

Kevbrina M. V., Belov N. A., Akmentina A. V., Ostapenko R. V.

The efficiency of aeration systems at the Moscow wastewater treatment facilities under field operating conditions

Summary

Aeration systems of aeration tanks are key elements of the wastewater treatment facilities. The main task in operating different types of aeration systems is ensuring high efficient atmospheric oxygen utilization at low energy consumption. The specialists of R&D Centre of «Mosvodokanal» JSC investigated the results of the long-term operation of the aeration systems at the Moscow wastewater treatment facilities under field operating conditions. The dependence of the aeration system efficiency on the ratio of surface areas of aerated zone and aeration tank; the air flow rate through one aerator at different options of aerators layout along the aeration tank length was studied. Regulating specific air consumption in the aeration tank zones provides for the optimal use of the available oxidation potential of the facilities without increasing aeration expenses or decreasing the efficiency of wastewater treatment. It was stated that when designing and choosing aeration systems it is necessary to find a balance between the surface area of the aerated zone in the aeration tank and efficiency of the aeration system. It was shown that when introducing nitrification-denitrification technologies without increasing capital and operating expenses for purchasing and maintaining mixing and aeration equipment both short-term and long-term shutdown of the aerators is possible to provide for alternate aeration without any efficiency loss. Perennial studies of the aeration systems produced by different manufacturers showed that the efficiency of the aeration systems during long-term operation is reduced by 25% of the design value. Therefore when choosing and designing an aeration system the reduction of the aeration system efficiency during the operation at the existing treatment facilities shall be taken into account aside from the required number of aerators and their layout.

Summary

wastewater , biological treatment , aeration tank , activated sludge , aeration system , efficiency of oxygen transfer