RESULTS OF PILOT TESTS OF THE VSEP TECHNOLOGY ON THE EXAMPLE OF PURIFICATION OF CONTAMINATED ACID WASHING WATERS BY NANOFILTRATION

Shown are the results of a series of pilot tests for the purifi cation of waste (contaminated) acidic wash water formed during the production of graphite by the leaching method. The tests were carried out in laboratory and pilot modes (on-site) on the “LP” series machine. Purifi cation was simulated using nanofi ltration membranes using VSEP technology. This technology of vibro- membrane fi ltration makes it possible to purify such waters without preliminary purifi cation and the use of reagents (antiscalant) with a %Recovery more than 90 %. The mechanism for choosing the optimal sheet polymer membrane and the mechanism for determining the best working pressure are shown. Concentration series were carried out to determine the stability of the process and the duration of the fl ushing interval. The test results allow the design of an industrial water purifi cation system.

EFFECTIVENESS ANALYSIS OF SOFTENING METHODS OF WATER FROM NATURAL SOURCES

The results of chemical analysis of natural waters from surface (river, water supply) and underground (well, well) sources are given. Water selection for analysis was carried out in a number of cities and villages of the Samara and Penza regions. The analysis was performed on the following indicators: total stiff ness, hydrogen index, calcium, magnesium, iron cations, chlorides, sulfates, hydrocarbonates, permanganate oxidability. The most common chemical indicator of water quality exceeding MPC was identifi ed. The negative impact of rigid water on the operation of boiler units and household needs is shown. Various methods of water softening are illuminated. The results of determination of water hardness before softening and after fi ltration through a layer of cationite and anionite are presented. Based on the obtained indicators, recommendations are given on the selection of softening methods for various types of boilers.

EFFECTIVENESS ANALYSIS OF SOFTENING METHODS OF WATER FROM NATURAL SOURCES

The results of chemical analysis of natural waters from surface (river, water supply) and underground (well, well) sources are given. Water selection for analysis was carried out in a number of cities and villages of the Samara and Penza regions. The analysis was performed on the following indicators: total stiff ness, hydrogen index, calcium, magnesium, iron cations, chlorides, sulfates, hydrocarbonates, permanganate oxidability. The most common chemical indicator of water quality exceeding MPC was identifi ed. The negative impact of rigid water on the operation of boiler units and household needs is shown. Various methods of water softening are illuminated. The results of determination of water hardness before softening and after fi ltration through a layer of cationite and anionite are presented. Based on the obtained indicators, recommendations are given on the selection of softening methods for various types of boilers.

Laparoscopic Surgery in COVID-19 Era in a Tertiary Hospital in Nepal

Introduction: There is great concern and risk of transmission of COVID-19 infection from the aerosolized smoke during laparoscopic surgery although there is a lack of enough literature to prove this. To minimize these risks and get the benefi t of laparoscopic surgery, we used a low-cost fi ltration system connected to an underwater seal bag fi lled with a 5% sodium hypochlorite solution.Materials and Methods: This is a retrospective study of prospectively maintained data of cases of laparoscopic surgeries using a low-cost fi ltration device system connected with an underwater seal bag fi lled with 5% sodium hypochlorite solution. Use of personal protective equipment, minimal staff in operative theatre, preoperatively testing of patients before admission for surgery was done. During surgery, minimal use of electrocautery in low power setting maintaining low pneumoperitoneum and cautious desuffl ation of smoke during and end of the procedure from one of the trocars fi tted to heat and moisture exchanger Filter, connected through a tube to 5 % sodium hypochlorite solution in underwater seal bag was performed.Results: During the lockdown from May 2020 to October 2020, 41 elective laparoscopic surgeries were done. All patients were tested negative before the procedure. No staff in operation theatre developed symptoms of COVID-19 or tested positive for COVID-19 infection for up to 2 weeks period.Conclusions: In this Pandemic situation, we have to co-habit with this SARS-Cov-2 virus. Minimally invasive surgeries can be continued with safety measures with modifications like the use of low-cost filtration devices for smoke filtration and evacuation.

4D modeling of concentrating mill tailings dam protecting dike soil consolidation

Introduction. The research aims to study concentrating mill tailings dam protecting dike soil consolidation on the example of a mining enterprise of the Kola Peninsula. Research methodology. The research is based on 4D modeling (taking into account a time factor) using PLAXIS software solution. The computer hydro-geomechanical 3D model of the concentrating mill tailings dam fragment has been developed allowing to investigate both geomechanical and fi ltration processes, and their collateral infl uence on protecting dike and alluvial beach soil consolidation. The following options of tailings dam hydro-geomechanical condition development are considered: a reference state at the current parameters of operation, increase in the level of water-saturated tail deposits and the subsequent consolidation of bulk and alluvial soils within 1, 2, 3, 5, 10, 15, 20, 30, 50 and 80 days. Research results and analysis. The received results have been analyzed on the dynamics of the tailings dam hydro-geomechanical condition therefore revealing its behavior in time. It has been established that the nature of bulk and alluvial soils consolidation is identical, however, differs signifi cantly in terms of quantity. Conclusions. Dependences of bulk and alluvial soils consolidation of the tailings dam hydraulic engineering construction on consolidation time are established providing a scientifi c and technical basis for its mechanical state and stability assessment, and for engineering recommendations about the terms of the following stage of dams building.

Refi ning of nickel alloys using foam ceramic fi lters

It is shown that fi ltration of nickel alloy by ceramic foam fi lters is effective way to reduce the number of non-metallic inclusions. Features of fi ltration refi ning of KhN45MVTYuBR alloy are studied. The effect of fi ltration refi ning on the microstructure and the chemical composition of the alloy is studied. The prospects for application of ceramic foam fi lters to improve the microstructure of the alloy KhN45MVTYuBR are shown.

INFLUENCE OF FILTRATION IN THE BODY OF AN ACTIVE PROTECTIVE STRUCTURE ON THE FLOW CHARACTERISTICS

The article describes the numerical model of the fl ow that envelops the shore protection structure in the form of a stream spur. Various from the point of view of permeability, spur body material options are considered. To model turbulent fi ltration as local resistance in the fl ow, a formula is proposed that relates the fi ltration coeffi - cient to the hydraulic resistance coeffi cient of a permeable medium. As a result of the simulation, images were obtained in the form of a planned distribution of velocities and pressures in the vicinity of the structure. The obtained materials indicate the relative position of the transit and whirlpool zones of the fl ow. Conclusions are drawn about the nature of the stream fl owing around the shore protection structure and the eff ect of fi ltration in the body of the structure on the characteristics of this stream.

THE EFFECT OF ANIONIC AND NONIONIC CO-SURFACTANT FOR IMPROVING SOLUBILITY OF POLYOXY-BASED SURFACTANT FOR CHEMICAL FLOODING

Surfactant is one of the crucial components for chemical flooding to recover oil production in the tertiary stage of the low primary and secondary recovery oil field. The mechanism is performed by decreasing the interfacial tension of oil and water which enhancing microscopic displacement efficiency. The present study showed the effect of commercial nonionic and anionic co-surfactant Tergitol, Teepol, Merpol, and SDS on the solubility of polyoxy based-surfactant (POS) through compatibility analysis, fi ltration ratio analysis, and IFT measurement. Whereas the presence of Teepol and Merpol did not change the original compatibility of POS in all concentrations, the addition of co-surfactant Tergitol and SDS were able to alter the solubility of POS from milky solution into a clear transparent solution. However, the most important characteristic of surfactant for reducing the IFT of oil-water was affected by the addition of co-surfactant which does not have sufficient IFT to release the trapped oil in the reservoir. Thus, exposing the mixture of surfactant and co-surfactant for a few days at the reservoir temperature has changed the visual appearance of solution from a clear transparent solution into a milky suspension, indicating the occurrence of thermal degradation. These results suggest that the addition of anionic and nonionic co-surfactant improved the solubility of POS, but increased the IFT. It can be concluded that the compatibility of POS in the brine can then be achieved by mixing it with suitable co-surfactant. Screening the other co-surfactant is required to obtain the one that enhances the compatibility as well as maintaining the ultralow IFT of POS.

THEORETICAL FEATURES AND PRACTICAL APPLICATION OF AERATION OF MULTICOMPONENT DYNAMIC GEOLOGICAL ENVIRONMENTS

A mathematical model of gas fi ltration through a porous medium is described, which describes the movement of air during high-pressure forced aeration, which is needed to maintain a high metabolic rate of oil-destroying microorganisms. Aeration is necessary to create an aerobic environment when applying a promising method of sanitation of the geological environment by injecting a special composition containing oil-destroying microbial additives into the lenses of oil products. The equation of fi ltration in polar coordinates is obtained, taking into account the experimental data, which describes the dynamics of gas movement in a porous medium under conditions of forced high-pressure aeration. The functional dependences are revealed, when obtaining the values of which one can solve the obtained fi ltration equation.

STUDY OF THE POSSIBILITY OF USING MICROWAVE RADIATION FOR THE TREATMENT OF LIQUID MUNICIPAL WASTE

The article is devoted to the study of the infl uence of microwave electromagnetic radiation (UHF EMP) on the properties of sewage sludge. The possibility of using microwave radiation for their processing is shown. The results of experiments confi rming the positive eff ect of the process under study on the degree and speed of compaction of a mixture of precipitation and activated sludge, improvement of their moisture yield, an increase in the yield of heavy metal impurities in decanted water, a decrease in the specifi c resistance of fi ltration and capillary suction of the sediment, precipitation. A hypothesis is proposed for the eff ect of UHF EMP on wastewater sludge.