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3 edition of The effect of a surface active agent on oxygen transfer in air-water systems found in the catalog.

The effect of a surface active agent on oxygen transfer in air-water systems

Khalil H. Mancy

The effect of a surface active agent on oxygen transfer in air-water systems

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Published .
Written in English


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Statementby K.H. Mancy.
ID Numbers
Open LibraryOL19546291M


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The effect of a surface active agent on oxygen transfer in air-water systems by Khalil H. Mancy Download PDF EPUB FB2

Using sodium lauryl sulfate, the effect of a surface active agent on oxygen transfer rate in bubble aeration was studied experimentally. It was found that the value of liquid film coefficient in bubble aeration was reduced by the addition of small amounts of sodium lauryl sulfate, less than ppm, to about one-fourth of that obtained in the case without the by: 7.

Oxygen Transfer Review 29 Surfactant Effects on Oxygen Transfer 35 Alpha, Beta and Theta Factors 40 Summary 43 3 Experimental Design 44 Dynamic Surface Tension Apparatus 44 Sensitivity Analysis for Pressure Head 48 Equations for Surface Tension 49 Aeration Apparatus 52 Surfactants surfactants to oxygen permeability and addressed the importance of experimental methodology.

The The effect of a surface active agent on oxygen transfer in air-water systems book mass transfer rate in the airwater surface layer was calculated by using an original technique and the results were compared to the surface tension values obtained by the Du Nouy ring method.

Abstract. This review paper is primarily concerned with the mechanics of oxygen absorption across the free surface of natural bodies of water. A summary is given of basic concepts related to the solution of oxygen in water, to the rate at which oxygen is absorbed by water, and to the manner in which turbulence in the water influences the absorption or reaeration process, A review is given of.

Those lowering surface tension increase oxygen transfer rate which might be due to decreased bubble size rather than any direct-interfacial film effect. CO 2 accumulation: In cases of secondary metabolism of microorganisms CO 2 plays a role, both in dissolved and in gaseous phase, on oxygen transfer in the liquid.

Our present knowledge. Air Flowrate Study the effect of air flowrate on the value of the mass transfer coefficient. With the agitation rate set at rpm, perform the experiment with several air flowrates: Lmin, Lmin, Lmin, Lmin and Lmin.

Convert these volumetric flowrates into superficial gas velocities. Effect of oxygen vector. Oxygen vectors are compounds that enhance the OTR through microorganisms when added to growth media owing to their higher oxygen solubilization capacity than that of water.

The main oxygen vectors used in biotechnology are hydrocarbons and perfluorocarbons, as well as oil added as an antifoaming agent.

bubble to the water surface, while at the same time the absorption of oxygen will cause a decrease in surface area. The two effects are thus compensatory in character. However, their relative influence on the area change for the two gases investigated must be more clearly defined.

In an attempt to ac count for expansion, the mean of the. transfer rate of oxygen from air to waste water subjected to biologically treatment. the rate of oxygen transfer essential for specification of aerator to be utilize this process Fine bubble aeration is known for a higher oxygen transfer efficiency than surface aeration, but equipment costs as well as maintenance.

Reduced water velocity and pumping effect Bubble detention time maximized. weight percent of oxygen in air minutes per day. SOR. (SOTE)() Air Rate scfm. SOR SOTE. Oxygen Transfer Testing. Clean Water Oxygen Transfer Testing. The effect of dispersed n dodecane or n hexadecane on the airtoaqueous phase overall volumetric oxygen transfer coefficient in a simulated (cellfree) stirredtank fermentor is described.

The oil volume fraction ranged from zero to ; the ionic strength of the aqueous phases was varied from 0 to The airtoaqueous phase coefficients in both oilfree (K L a) and. low rate of oxygen transfer, sufficient oxygen to meet the requirements of aerobic waste treatment does not enter water through normal surface air-water interface.

To transfer the large quantities of oxygen that are needed, additional interfaces must be formed. Oxygen can be supplied by means of air or pure oxygen. sludge plants. The effect of surfactants on oxygen transfer is also studied and a method to determine the floc volume of activated sludge is developed.

The α-factor, i. the relationship of wastewater to clean water oxygen transfer coefficient, is chosen to enable comparison of oxygen transfer coefficients. Here are four key variables that can affect kLa values: 1. Gas bubble size. When gas bubble size decreases, surface area and gas residency time increases, causing bubbles to stay in the culture longer.

Thus, there is a greater opportunity for oxygen to release mass transfer into the cell culture medium. Molder E, Tenn T, Tenno T () Research of oxygen mass transfer through the air-water surface at low bulk concentrations of surfactants.

Proc Est Acad Sci 58(2) Article CAS Google Scholar Oliveira MEC, Minkowycz WJ () Simulation of oxygen mass transfer in aeration systems.

Heat Mass Transf 25(6) transfer for the air bubbles and one for the oxygen transfer at the water surface. The model appeared to be sensitive for which initial guesses that was used for the estimated parameters and it was assumed to reduce the models usability.

Model nr 3 considered that the dissolved oxygen equilibrium concentration in water is depth dependent and. Oxygen Transfer Efficiency There are different types of aeration systems, but subsurface or diffused aeration systems are most common, especially for large plants in urban areas For these types of aeration systems, it is common to define the oxygen transfer efficiency, expressed as a percent, as follows: 2,in 2,out 2,in (O O) OTE O.

β is used to correct the test system oxygen transfer rate for differences in oxygen solubility due to constituents in the water such as salts, particulates, and surface-active substances β ( is commonly used for ww) 11 () () Cs tap water C s wastewater.

The oxygen transfer in diffused aeration systems can be divided into two processes: bubble oxygen transfer and surface oxygen transfer. Bubble oxygen transfers into the water across the bubble-water interface as the bubbles rise from the diffuser to the water surface. Surface. Surface active agents Dyes Gaseous Formaldehyde Ethylene oxide action of water and oxygen.

In the presence of water much lower temperature. 43 Sterilisation and Disinfection chamber of Litre capacity and surrounded by a water jacket.

Air is removed from sterilizer by evacuation, humidification and conditioning. transfer occurs. Oxygen transfer occurs across the bubble interfaces as the bubbles rise through the water column.

Oxygen transfer also occurs across the water surface where oxygen in the air dissolved into water. At the water surface, oxygen transfer is driven by. surface to entrain DO in the aeration tanks (mechanical aeration) or through introducing oxygen into the aeration tanks through porous devices (diffused aeration).

Aeration systems are designed to increase the air-water interface within a process liquid, allowing for sufficient oxygen transfer required to support the biological processes.

transfer of ozone to the wastewater. The amount of ozone that will dissolve in wastewater at a constant temperature is a function of the partial pressure of the gaseous ozone above the water or in the gas feed stream. It is critical that all ozone disinfection systems be pilot tested and calibrated prior to installation to.

The dissolved oxygen concentration, for all practical purposes, will be zero and the KLa may then be calculated from the equation: (where OTR is the oxygen transfer rate) Disadvantages i) slow, ii) effected by surface active agents iii) Rheology of solution not like media Cu or Co 2.

) and is expected to prevail in most environmental systems. Factors Impacting Nucleation The size and number of bubbles nucleated depends on the history of the water body and type of suspended particles (Keller ).

The number of nucleation sites generally increases in the presence of surface active agents (Jackson ). Rough. The oxygen-transfer coefficient is directly proportional to the dynamic gas holdup. Stagnant gas holdup does not influence the rate of oxygen transfer.

The results suggest that dynamic gas holdup largely determines the specific interfacial area (a), whereas the interstitial liquid velocity largely controls the oxygen-transfer coefficient (K L).   Oxygenation systems are naturally much more efficient than straight aeration with air being 79 percent nitrogen and only about 21 percent oxygen.

Likewise, percent oxygen offers about five times the oxygenation capacity of a forced air system. Oxygen may be injected into wastewater in a number of ways.

In supplemental systems, the oxygen. A typical aeration system increases the amount of Oxygen in the system by (air has about 21 Oxygen). More recently, plants have begun using pure Oxygen transfer systems, which use liquid Oxygen (LOx) and specially designed delivery devices to achieve Oxygen transfer on the order of.

Oxygen enters water bodies primarily by transfer from the atmosphere across the air-water interface and to a lesser extent by the action of photosynthetic organisms (See Biotic Factors for explanation). Transfer of oxygen across the air-water interface is facilitated by increasing the surface area exposed to the atmosphere.

Experimental treatments with air showed similar, but much less dramatic effect of the gas flow rate to water flow rate ratio and water inlet velocity on K L a 20, SOTE, SAE, and SOTE, when compared to treatments with PSA oxygen. The best oxygen transfer performance was achieved with an inlet water velocity of m s 1 and oxygen.

Chapter Water Sources, Impurities in Water and Chemistry. Abundant supplies of fresh water are essential to the development of industry. Enormous quantities are required for the cooling of products and equipment, for process needs, for boiler feed, and for sanitary and potable water supply.

Oxygen is added to water by: Re-aeration: Oxygen from air is dissolved in water at its surface, mostly through turbulence. Examples of this include: Water tumbling over rocks (rapids, waterfalls, riffles) Wave action Photosynthesis (during daylight) Plants produce oxygen when they photosynthesize.

Notice that this pressure is less than the external air. Therefore, the oxygen will flow from the inspired air in the lung (P O 2 mm Hg) into the bloodstream (P O 2 mm Hg) (Figure ). In the lungs, oxygen diffuses out of the alveoli and into the capillaries surrounding the alveoli.

LECTURE NOTES Subject: Surface Chemistry and Nuclear Chemistry Faculty: Dr. Monalisa Mohapatra Subject Code: CH 2nd Semester 2yr and 8th Semester 5yr Int.

Module-I: (10 Hours) Phase Rule and Catalysis: Derivation of Phase Rule, Brief Concept on One and Two Component System, Application of Phase Rule to Three Component Systems of Both Solids.

temperature as wind action mixes the water from top to bottom. As air temperatures increase in spring and sum-mer, lake water also warms up. Surface water warms more rapidly than deeper water.

Because the warmer, surface water is lighter than the colder, deeper water, these lakes separate into three distinct thermal layers (Fig. Acids and Alkalies The pH in a biological system, such as in surface water or treatment plants, is an important factor because a sudden change can cause serious damage.

The measurement used to determine the required dosage of neutralizing agent, either Ca(OH)2 oris termed acidity or alkalinity, respectively. This process utilizes air-water contact to transfer oxygen. As the water is propelled into the air, it breaks into small droplets.

Collectively, these small droplets have a large surface area through which oxygen can be transferred. Upon return, these droplets mix with the rest of the water and thus transfer their oxygen back to the ecosystem.

Sleep, Stress, Pain, and Cortisol. A pilot study evaluated diurnal rhythms in cortisol correlated with changes in sleep, pain, and stress (anxiety, depression, and irritability), as monitored by subjective reporting [].

Twelve subjects with complaints of sleep dysfunction, pain, and stress were grounded to Earth during sleep in their own beds using a conductive mattress pad for 8 weeks.

However, it may be that, due to a particular set of field conditions, a surface water may have to be treated. Demonstrated oxygen transfer rate effects due to water chemistry differences between the field conditions and the prior test data used to predict the field performance may be considered in agreeing upon any water quality modifications.

Comparative respiratory physiology: the fundamental mechanisms and the functional designs of the gas exchangers John N Maina Department of Zoology, University of Johannesburg, Johannesburg, South Africa Abstract: Acquisition of molecular oxygen (O2) from the external fluid media (water and air) and the discharge of carbon dioxide (CO2) into the same milieu is the primary role of respiration.

Human respiratory system - Human respiratory system - Transport of oxygen: Oxygen is poorly soluble in plasma, so that less than 2 percent of oxygen is transported dissolved in plasma. The vast majority of oxygen is bound to hemoglobin, a protein contained within red cells.

Hemoglobin is composed of four iron-containing ring structures (hemes) chemically bonded to a large protein (globin). Other sources of oxygen include the air and inflowing streams.

Oxygen concentrations are much higher in air, which is about 21% oxygen, than in water, which is a tiny fraction of 1 percent oxygen. Where the air and water meet, this tremendous difference in concentration causes oxygen molecules in the air to dissolve into the water.