bbk 000000

UDC 628.237

Fedorov Sviatoslav Viktorovich, Vasilyev V. M., Klementyev M. N.

Study of gas evolution in a sewer section

Summary

Transportation of wastewater through sewer networks is accompanied by the generation and evolution of gases from the flow. For a quantitative assessment of the gas evolution process a sewer section model has been developed in the ANSYS CFX finite element analysis package. The model takes into account the combined flow of wastewater, entrained air and sewage gas (e.g. carbon dioxide) coming from the collector tray. Monitoring was carried out in a section of the domestic sewage system (DN = 500 mm) in the industrial zone of Obukhovo in St. Petersburg. The measured values of the vacuum pressure are in the range of model calculations. The process of designing a computational area of the sewer section and establishing initial and boundary conditions is presented. As a result of modeling the dependences of the carbon dioxide concentration and the pressure of the gas-air environment in the underroof space of the pipeline with different slopes and filling levels were obtained. The results obtained can serve as a basis for the approach to predicting the process of gas evolution in sewer sections.

Key words

monitoring , simulation , ecological safety , sewerage network , carbon dioxide , hydrogen sulfide , methane , ammonia , gas evolution intensity

Скачать/download (PDF) free access

DOI 10.35776/VST.2022.09.07
UDC 628.16.081.32

Ahmed Sameh Abdelfattah Araby, Gogina Elena

Study of the competitive adsorption of a mixture of phenol and ammonia nitrogen on activated carbon

Summary

Phenol and ammonia nitrogen are considered typical pollutants present in industrial wastewater from various industries. Application of the response surface methodology (RSM) was used to develop a mathematical model for the simultaneous adsorption of phenol and ammonia nitrogen on activated carbon. The combined effect of pH, carbon doses, the initial concentration of phenol, and the initial concentration of ammonia nitrogen on the efficiency of adsorption was studied. Simulation using RSM gave a nontransformed quadratic model for phenol removal and a square root transformed linear model for ammonia nitrogen removal. The results of the study showed a positive effect of increasing the carbon dose on the adsorption of phenol, while an increase in the initial concentration of phenol had a negative effect on the efficiency of its adsorption. Almost complete removal of phenol was achieved within 90 minutes at pH4. In addition, the adsorption of ammonia nitrogen improved with increasing pH and carbon dose. The presence of ammonia nitrogen adversely affected the removal of phenol with pH increasing. However, the presence of phenol does not affect the adsorption of ammonia nitrogen.

Key words

wastewater , simulation , phenols , adsorption , ammonia nitrogen , activated carbon

DOI 10/35776/MNP.2019.09.09
UDC 628.2+532.54

Dezhina I. S., Orlov V. А., Zotkin S. P.

The study of the surface texture of pipes with the purpose
of increasing their transporting capacity

Summary

The results of exploratory research on the transportation of water and sand in specially designed laboratory and work benches including a platform with replaceable modular polymer elements (troughs) with artificial roughness are presented. The methodology of experiments on large benches with modular piped elements using photo- and film equipment as well as devices for determining velocity, filling and slope is presented. The nature of the turbulence zones with a different texture of the inner surfaces of the troughs in the form of obstructions of different height is revealed. The results of hydraulic experiments are presented in two modes: single-phase (water without foreign inclusions) and two-phase (water mixed with sand of different fractional composition). According to the results of experimental studies the areas of effective operation of modular troughs for sand transportation for various textures of artificial roughness of pipes of sewer systems were identified. The expediency of using corrugated inner walls of pipelines transporting wastewater for the efficient removal of sand belts settled on the bottom and walls of the pipes is substantiated.

Key words

simulation , transporting capacity , gravity sewers , artificial pipe roughness , microturbulence

Скачать/download (PDF) free access

DOI 10.35776/VST.2022.08.05
UDC 628.35

Epov A. N., Danilovich Dmitrii

On the discussion on the comparison of methods for calculating aeration tanks with the removal of nitrogen and phosphorus (for the discussion)

Summary

The arguments of the authors of the book «Calculation and process engineering of processes and facilities for the removal of nitrogen and phosphorus from municipal wastewater» are given in response to the critical article by O. V. Khar’kina in the «VST» journal on the method proposed for calculating aeration tanks. Based on the literature review, it is shown that the calculation of aeration tanks in terms of the sludge age is not empirical, however based on the kinetic laws; and, herewith, in the field of application recommended by the authors, the use of a smaller number of empirical coefficients is required eliminating their choice. Explanations are given why accounting for the concentration of dissolved oxygen and calculation for the nitrite nitrogen concentrations less than 0.05 mg/l should not be included in the calculation procedure. Explanations are given for the dependence of kinetic coefficients on the concentrations in the effluent because of the change in the species composition of nitrifiers according to the theory of competitive exclusion of species. Information is provided on the successful comparison of the methods proposed by the authors with the simulation in the GPS-X program and on the operation of a new block of the Liubertsy Wastewater Treatment Facilities (Moscow), calculated according to the method. The operation of the block testifies to the complete sufficiency of the volume of the aerobic zone of the aeration tanks.

Key words

wastewater , biological treatment , nitrification , simulation , sludge age , kinetic coefficients

bbk 000000

UDC 581.526.325

Babaev A. V., Zamana G. T., Puklakov V. V.

Model prediction of water quality patterns
in the Mozhaiskoe water reservoir under the heat wave conditions

Summary

The issues of water quality in water reservoirs used for public water supply are of primary concern. Intensive phytoplankton development in them is a most common problem in water supply. Therefore the selection of tools that provide for predicting to a high degree of accuracy the processes of water quality formation in water reservoirs under various hydro meteorological summer conditions is a task of primary importance. The results of the model prediction of the basic water quality patterns under the heat wave conditions and of the diagnostic calculation of the environmental conditions of the Mozhaiskoe water reservoir in 2014 carried out according to GMV-MGU model and verified by the field studies data are presented. The verification showed good reproduction of the water quality patterns of the Mozhaiskoe water reservoir by the model. The comparison of the model prediction results, diagnostic calculation and field studies data showed that the model prediction of the water reservoir conditions for the minimum winter storage decrease, low flow spring tide and excessive summer heat is coherent with the actual 2014 pattern when similar hydro meteorological conditions were observed. GMV-MGU model can be used for predictions and diagnostic calculations of water quality patterns in the water reservoirs used for public water supply in the process of planning the measures on operating and long-term control of hydroengineering facilities and water intakes operation.

Key words

simulation , water quality , reservoir , phytoplankton , heat wave , anoxia

bbk 000000

UDC 628.22:532.542

Chupin V. R., Melekhov E. S., Chupin R. V.

Pressure Movement of Flows in Gravity Manifolds

Summary

A new approach to the design of water disposal systems based on their simulation with hydraulic chains with unrecorded withdrawals and inflows of runoffs is offered. It makes it possible, on one hand, to determine the presence of counterflows in the network, possible effusions of flows on the ground surface, volumes of runoffs running out, carrying capacity of a water disposal system and, on the other hand, to simulate various conditions of flow transportation with due regard for possible cloggings, encrustation of pipes and other violations which can occur during the operation.

Key words

wastewater , head , water disposal system , collector , hydraulic design , well , simulation