scholarly journals Water disinfection under the helium influence

2021 ◽  
Vol 4 (3(60)) ◽  
pp. 6-8
Author(s):  
Iryna Koval
Keyword(s):  
Natural Waters ◽  
Unit Volume ◽  
Aqueous Media ◽  
Reaction Medium ◽  
Research Process ◽  
Water Disinfection ◽  
Bacterial Cells ◽  
Treatment Technology ◽  
Running Water ◽  
Number Of Microorganisms

The object of research is the process of water disinfection at the influence of gas from bacteria of a particular genus with different amounts per unit volume of water. Due to the annual increase in the amount of pollutants in natural waters, new opportunities to improve microbiological indicators of water quality are being explored. There are many different ways to disinfect it, both physical and chemical. However, no single method has been found to purify aqueous media from microorganisms that would ensure their effective destruction. It is proposed to study the activity of specific microorganisms during the bubbling of inert gas through the aqueous medium. The microorganisms studied were rod-shaped sporogenic cells of Bacillus cereus bacteria type. The test gas was inert helium. The study used continuous gas bubbling throughout the process, which allowed to mix microbial water efficiently and prevent the formation of stagnant zones in the reaction medium. In particular, active gas mixing facilitates its access to each cell. The gas supply rate corresponded to 0.2 cm3/s, and its flow rate was 0.7 dm3 for one hour of bubbling through microbial water. The duration of the entire research process was 7200 s. The constant temperature of the microbial water (T=288±1 K) was maintained during the experiment by cooling the glass reactor with running water. An in-depth method of culturing bacterial cells was used. A decrease in the number of microorganisms was observed throughout the helium supply process, despite the different initial amounts in the water. The highest destruction degree of bacillus (77.06 %) was obtained at the lowest studied concentration in water (NM01=3.4·104 CFU/cm3). This is due to the fact that less microbial load provides better conditions for access of helium to the cell and their effective destruction. The proposed method of water purification allowed to achieve a sufficiently high degree of water disinfection from sporogenic rod-shaped bacteria after the action of helium alone. In particular, it has been experimentally proven that the efficiency of the water disinfection process depends on the concentration of microorganisms per unit volume of water. Due to the treatment of contaminated water with gas, it is possible to obtain high rates of its purification and the application of this method for practical purposes in water treatment technology.

scholarly journals Influence of Aerobic Bacteria Concentration on the Process of its Survival in the Presence of Oxygen

2020 ◽  
Keyword(s):  
Unit Volume ◽  
Aqueous Media ◽  
Oxygen Atmosphere ◽  
Aerobic Bacteria ◽  
Bacterial Cells ◽  
High Concentration ◽  
Aquatic Medium ◽  
Subsequent Decrease ◽  
Before And After ◽  
Number Of Microorganisms

Purpose of the study is to study the viability of aerobic microorganisms in an oxygen atmosphere with different initial content in the aquatic medium. Compare the effect of gas on different concentrations of bacteria per unit volume of the water. Methods. Aerobic bacteria of the genus Bacillus cereus bacteria type were the studied microorganisms. Model aqueous media were created on the basis of distilled deaerated water with the addition of bacteria of a particular type. Oxygen was bubbled into the microbial water throughout the process at a rate of 0.2 cm3/s. The duration of the study was 2 hours, during which the total gas consumption corresponded to 1.4 dm3. The number of microorganisms (NM) before and after the experiments was determined by counting the colonies that grew on the Petri dishes. Results. A two-stage process of oxygen exposure to aerobic bacteria was detected - accumulation and reduction of its number per unit volume of water during all experiments. At the first stage of the process, there was an increase of NM during 1800-3600 s with its subsequent decrease (II stage). With an increase in the microbial load in the water from 102 to 104 CFU/cm3, the duration of the process of bacterial accumulation was decreased in two times. An active reproduction of bacterial cells was investigated at the low concentration of bacteria in the water, and its active reduction - at the high concentration that is explained by cells destruction under conditions of constant supply of oxygen of the established rate. Conclusions. The oxygen influence on the change of the number of aerobic microorganisms in the aquatic medium is explained. It is investigated that the oxygen action on bacteria in the water divides the process of its viability into two stages: accumulation (I stage) and reduction of its number (II stage). It is shown that the duration of the process of bacteria accumulation in the oxygen atmosphere depends on its initial amount in the water, namely with increasing of the initial NM per unit volume of the water, the duration of the stage of microorganisms accumulation decreases significantly.

scholarly journals THE EFFICIENCY OF THE WATER PURIFICATION PROCESS FROM BACTERIA DEPENDING ON THE GAS NATURE

2021 ◽  
pp. 41-44
Author(s):  
Iryna Koval
Keyword(s):  
Carbon Dioxide ◽  
Water Treatment ◽  
Water Purification ◽  
High Efficiency ◽  
Total Duration ◽  
Reaction Medium ◽  
Microbial Count ◽  
Bacterial Cells ◽  
Subsequent Decrease ◽  
Number Of Microorganisms

A study of the influence of different gas nature on the efficiency of water purification from rod-shaped bacteria of the Bacillus cereus type is presented. The action of oxygen, carbon dioxide and inert argon and helium were used. The investigated water was model microbial water obtained on the basis of deaerated distilled water with the introduction of a pure culture of bacteria in the amount of 7 · 104 CFU/cm3. The total duration of the process was 2 hours at a reaction medium with temperature of 288 ± 1 K. The change in the number of microorganisms from the duration of gas bubbling is shown, depending on its nature. The degrees of destroyed microorganisms were calculated after each sampling of water (Dd), which was taken after each 30 min of the process. Studying the influence of different modes of water treatment, the largest number of destroyed bacterial cells was studied in an atmosphere of carbon dioxide (Dd = 91.0 %), and the smallest - in an atmosphere of oxygen (Dd = 34.73%). A two-stage process of number of microorganisms change was detected in the oxygen atmosphere: an increase in the first stage during 1800 s and a subsequent decrease in the second stage. After CO2 bubbling with a rate of 0.2 cm3/s through an aqueous medium with a volume of 75 cm3, the microbial count decreased by two orders of magnitude, which is apparently due to an increase in the acidity of the test medium. Having found a high efficiency of CO2 on the process of bacterial cells destruction, this gas should be used in water treatment processes, as well as in combination with other reagents or physical methods of water treatment to enhance the destructive effect on micro-objects.

scholarly journals Chromate Reduction in Serratia marcescens Isolated from Tannery Effluent and Potential Application for Bioremediation of Chromate Pollution

2002 ◽  
Vol 2 ◽  
pp. 972-977 ◽  
Author(s):  
M.A. Mondaca ◽  
V. Campos ◽  
R. Moraga ◽  
C.A. Zaror
Keyword(s):  
Natural Waters ◽  
Waste Treatment ◽  
Environmental Concern ◽  
Electron Microscopic Examination ◽  
Tannery Effluent ◽  
Chromate Reduction ◽  
Bacterial Cells ◽  
Electron Microscopic ◽  
Treatment Processes ◽  
Transmission Electron

Pollution of aquatic systems by heavy metals has resulted in increasing environmental concern because they cannot be biodegraded. One metal that gives reason for concern due to its toxicity is chromium. Cr(VI) and Cr(III) are the principal forms of chromium found in natural waters. A chromate-resistant strain of the bacterium S. marcescens was isolated from tannery effluent. The strain was able to reduce Cr(VI) to Cr(III), and about 80% of chromate was removed from the medium. The reduction seems to occur on the cell surface. Transmission electron microscopic examination of cells revealed that particles were deposited on the outside of bacterial cells. A stable biofilm was formed in less than 10 h, reaching around 1010cfu attached per milligram of activated carbon. These findings demonstrate that immobilizedS. marcescensmight be used in industrial waste treatment processes.

scholarly journals Study of Semi-Dry High Target Solidification/Stabilization of Harmful Impurities in Phosphogypsum by Modification

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 462
Author(s):  
Fenghui Wu ◽  
Can Yang ◽  
Guangfei Qu ◽  
Liangliang Liu ◽  
Bangjin Chen ◽  
...  
Keyword(s):  
Raw Materials ◽  
Reaction Medium ◽  
Calcium Carbide ◽  
Economic Cost ◽  
Treatment Technology ◽  
Polyaluminum Chloride ◽  
Industrial Solid Waste ◽  
Filling Materials ◽  
Leaching Toxicity ◽  
And Storage

Phosphogypsum (PG) treatment is one of the research hotspots in the field of environmental protection. Many researchers both at home and abroad have devoted themselves to studies on harmless resource treatment of PG, but the treatment technology is unable to meet the demand of PG consumption due to the huge production and storage demands. In order to solve the problem of PG pollution, this study explored the different solidified effects of various modification formulations on the hazardous components in PG, using industrial solid waste calcium carbide slag (CCS) as an alkaline regulator; Portland cement (PC), polyaluminum chloride (PAC) and CaCl2 as the main raw materials of the solidification and stabilization formula and the water content in PG as the reaction medium. The results showed that CCS (0.5%), PC (0.4%) and PAC (0.3%) had a more significant solidified effect on phosphorus (P) and fluoride (F). PAC was added in two steps and reacted under normal temperature and pressure, and its leaching toxicity meets the requirements of relevant standards, which laid an excellent foundation for PG-based ecological restoration materials and filling materials, with low economic cost, simple process and strong feasibility. This will provide great convenience for the later mining and metallurgy.

Greener routes to organics and nanomaterials: Sustainable applications of nanocatalysts

2013 ◽  
Vol 85 (8) ◽  
pp. 1703-1710 ◽  
Author(s):  
Rajender S. Varma
Keyword(s):  
Heterocyclic Compounds ◽  
Large Scale ◽  
Aqueous Media ◽  
Reaction Medium ◽  
Waste Minimization ◽  
Synthetic Activity ◽  
Coupling Reactions ◽  
Structured Catalysts ◽  
Strategic Approach ◽  
Solvent Free Conditions

Sustainable synthetic activity involving alternate energy input and greener reaction medium under aqueous or solvent-free conditions is summarized. This includes the synthesis of heterocyclic compounds, coupling reactions, and a variety of reactions catalyzed by basic water or recyclable and reusable magnetic nanocatalysts in aqueous media using microwave (MW) irradiation. Micropine-structured catalysts and magnetic nanoferrites and their post-synthetic modification with ligands and other nanometals serve as sustainable nanocatalysts in benign media. The strategic approach attempts to fulfill most of the green chemistry principles in a comprehensive manner and aims to create sustainable functional chemicals that may find large-scale use with significant waste minimization.

Микродвигатели новое направление создания технологий очистки воды и сточных вод (обзор)

2019 ◽  
pp. 54-60
Author(s):  
V. Kofman
Keyword(s):  
Heavy Metals ◽  
Catalytic Properties ◽  
Aqueous Media ◽  
Ultrasonic Waves ◽  
Water Disinfection ◽  
Energy Sources ◽  
Chemical Gradients ◽  
Electric And Magnetic Fields ◽  
Removal Of Heavy Metals ◽  
Autonomous Movement

Микродвигатели представляют собой автономные, выполняющие определенные функции самодвижущиеся микроустройства на основе неорганических, органических или биологических материалов. В конструкции микродвигателя реализованы две функции: автономное движение и эффективный захват и/или деструкция различных химических веществ, в том числе загрязняющих. Для обеспечения автономного движения устройство микродвигателей предусматривает создание локальных термических, акустических, химических градиентов, проистекающих из ассиметричной морфологии или поверхностной структуры. Движение обеспечивается за счет использования различных источников энергии, включая свет, электрические и магнитные поля, ультразвуковые волны или химическое топливо . Хаотичная траектория движения микродвигателей в объеме раствора обеспечивает высокоэффективное взаимодействие иммобилизованных на их поверхности реагентов с целевыми загрязняющими или детектируемыми веществами. Наиболее проработанный принцип создания автономного движения заключается в возникновении импульса отдачи при ассиметричном образовании в результате химической реакции газовых микропузырей. В настоящее время основные исследования применения микродвигателей в процессах водоочистки проводятся по направлениям анализа водных сред, удаления тяжелых металлов, органических загрязняющих веществ, красителей и нефтепродуктов, а также обеззараживания воды. По оценкам, микродвигателям присущи уникальные возможности в области детектирования и удаления загрязняющих веществ в водной среде вследствие сочетания адсорбционных и каталитических свойств с автономным перемещением.Micromotors are autonomous, performing certain functions, selfpropelled microdevices based on inorganic, organic or biological materials. Implemented in a micromotor design are two functions: autonomous movement and effective capture and/or destruction of various chemicals, including pollutants. To ensure autonomous movement the micromotor device provides for the creation of local thermal, acoustic, chemical gradients arising from asymmetric morphology or surface structure. The movement is provided through the use of various energy sources including light, electric and magnetic fields, ultrasonic waves or chemical fuel. The chaotic trajectory of micromotors throughout the solution provides for the highly efficient interaction of the chemicals immobilized on their surface with the targeted pollutants or detectable substances. The most elaborated principle of creating autonomous movement is the generation of a recoil impulse at asymmetric formation of gas microbubbles as a result of a chemical reaction. Currently, the main studies on the use of micromotors in water purification processes are carried out in the areas of analysis of aqueous media, removal of heavy metals, organic pollutants, dyes and oil products, as well as water disinfection. It is estimated that micromotors possess unique capabilities in the field of detection and removal of pollutants in aqueous media due to a combination of adsorption and catalytic properties with autonomous movement.

scholarly journals Use of the aqueous extract of Eucalyptus microcorys for the treatment in microcosm, of water containing Enterococcus faecalis: hierarchisation of cells' inhibition factors

2018 ◽  
Vol 1 (1) ◽  
pp. 47-56
Author(s):  
Tamsa Arfao Antoine ◽  
Lontsi Djimeli Chretien ◽  
Noah Ewoti Olive Vivien ◽  
Moussa Djaouda ◽  
Yaouba Aoudou ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Aqueous Extract ◽  
Water Disinfection ◽  
Bacterial Cells ◽  
Extract Concentration ◽  
Light Intensities ◽  
Incubation Periods ◽  
Incubation Duration ◽  
Major Factors ◽  
Aquatic Microcosm

Abstract An experimental study in aquatic microcosm was carried out to determine the major factors involved in the inhibition of Enterococcus faecalis in the presence of aqueous extract of Eucalyptus microcorys. The planktonic bacterial cells remained in various concentrations of the aqueous solution at light intensities which fluctuated between 0 and 3,000 lx and incubation periods which ranged from 3 to 24 hours. A hierarchisation of studied factors revealed that the aqueous extract concentration, followed by experimental temperature, light intensity and incubation duration influence the inhibition of E. faecalis cells, respectively, with a rate of 86.82%, 7.03%, 5.25% and 0.90%. The cell abundances dropped significantly at 1.5% (λ = 0.491 and F = 5.518) and 2% (λ = 0.568 and F = 4.055) concentrations coupled with 1,000, 2,000 and 3,000 lx. The highest light intensities and extract concentration produce the highest log removal values. The disinfectant properties of E. microcorys were evaluated by the Chick–Watson model. This Chick–Watson model so obtained varied between log (N/No) = −0.09 Ct and log (N/No) = −0.17 Ct for extract concentrations of 1, 1.5 and 2%. Aqueous extract of E. microcorys could be used for water disinfection.

scholarly journals A pulsed light system for the disinfection of flow through water in the presence of inorganic contaminants

2014 ◽  
Vol 13 (2) ◽  
pp. 406-412 ◽  
Author(s):  
Mary Garvey ◽  
Neil Rowan
Keyword(s):  
Uv Light ◽  
Water Disinfection ◽  
Bacterial Cells ◽  
Limited Data ◽  
Inorganic Contaminants ◽  
Test Species ◽  
Bacterial Endospores ◽  
Effective Form ◽  
Pulsed Uv Light ◽  
Flow Through

The use of ultraviolet (UV) light for water disinfection has become increasingly popular due to on-going issues with drinking water and public health. Pulsed UV light has proved to be an effective form of inactivating a range of pathogens including parasite species. However, there are limited data available on the use of pulsed UV light for the disinfection of flowing water in the absence or presence of inorganic contaminants commonly found in water sources. Here, we report on the inactivation of test species including Bacillus endospores following pulsed UV treatment as a flow through system. Significant levels of inactivation were obtained for both retention times tested. The presence of inorganic contaminants iron and/or manganese did affect the rate of disinfection, predominantly resulting in an increase in the levels of inactivation at certain UV doses. The findings of this study suggest that pulsed UV light may provide a method of water disinfection as it successfully inactivated bacterial cells and bacterial endospores in the absence and presence of inorganic contaminants.

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