Oxygen depletion

Oxygen is used in these microbiolreactions to degrade substrates, in this case organic wastes, to produce energy required for ceU synthesis and for respiration. A minimum residual of 0.5 to 2.0 mg/L DO is usually maintained in the reactors to prevent oxygen depletion in the treatment systems. 

The value of the saturation concentration,, is the spatial average of the value determined from a clean water performance test and is not corrected for gas-side oxygen depletion therefore K ji is an apparent value because it is determined on the basis of an uncorrected. A tme volumetric mass transfer coefficient can be evaluated by correcting for the gas-side oxygen depletion. However, for design purposes, can be estimated from the surface saturation concentration and effective saturation depth by... 

The reaction can be followed by measurement of dye formation. The rate of oxygen depletion can be measured using an oxygen electrode. Additional reagents can be added to prevent the formation of oxygen from the generated HpOp. The reactions ate as follows ... 

A typical fermentation medium for penicillin production contains lactose, com steep Hquot, and calcium carbonate (3,153,154). In most industrial processes the carbohydrate source, glucose, beet molasses, or lactose, is continuously added to the fermentation. The rate of glucose addition must be carefully monitored, by pH or rate of oxygen depletion, because the synthesis of penicillin is markedly reduced in the presence of excess glucose. 

As rust accumulates, oxygen migration is reduced through the corrosion product layer. Regions below the rust layer become oxygen depleted. An oxygen concentration cell then develops. Corrosion naturally becomes concentrated into small regions beneath the rust, and tubercles are born. 

Dissolved oxygen is the enemy of anaerobic bacteria. Naturally occurring corrosion consumes oxygen. Without convective replenishment, oxygen-depleted zones form and corrosion by anaerobes is usually worse. 

The process has two main sources of waste water. These are the condensate streams from the steam strippers. The principal pollutant in both wastewater streams is phenol. Phenol is of concern primarily because of its toxicity, oxygen depletion, and turbidity. In addition, phenol can cause objectionable taste and odor in fish flesh and potable water. 

The maximum temperature the drains and the water sinks can accept (bearing in mind thermal stresses and corrosion in discharge pipelines, and algae growth and oxygen depletion in the watercourses)... 

FIGURE 19.30 (a) Pyruvate reduction to ethanol in yeast provides a means for regenerating NAD consumed in the glyceraldehyde-3-P dehydrogenase reaction, (b) In oxygen-depleted muscle, NAD is regenerated in the lactate dehydrogenase reaction. 

The effect of deposits has been referred to in relation to organic matter. Oxygen depletion can, of course, also occur under other types of deposit. Water velocity plays some part here, as with a good flow deposition is less likely. 

Crevices, because they collect deposits and may promote corrosion by causing oxygen depletion in the crevice, thereby setting up a corrosion cell in which the areas receiving less oxygen corrode at a higher rate. 

In fed-batch mode residual substrate concentration may be maintained at very low levels. Ibis would reduce substrate costs, may remove catabolic repressive effects and may avoid possible toxic effects of the substrate. The fed-batch mode of operation may also avoid oxygen depletion of the culture during rapid growth. 

In reality, oxygen concentration never reaches the concentration defined in the proposed model, since the microbial activities at optimal and maximum cell density would reach the point where oxygen depletion takes place.5... 

The following chapter is a case study of how the three problem areas illustrated (dissolved oxygen depletion, erosion/deposition, and potentially toxic trace elements) may be successfully addressed on a major river system using quantitative, semi-quantitative and qualitative approaches respectively. 

The goals of this chapter do not include a "state of the art" literature review which would be appropriate for a more in-depth discussion of one particular problem area. Rather the intent is to illustrate mechanistic approaches to river quality assessment using the three globally relevant water quality problem areas discussed in the previous chapter dissolved oxygen depletion, erosion/deposition, and potentially toxic trace elements. The information provided does not include all rationale, methology or approaches used in the study as this is beyond the scope of the chapter. Additional general information on application of the intensive river quality assessment approach in the Willamette River basin may be found elsewhere (4-9, 11-14, 17). 

Ingall, E. D. and Jahnke, R. A. (1994). Evidence for enhanced phosphorus regeneration from marine sediments overlain by oxygen depleted waters. Geochim. Cosmochim. Acta 58, 2571-2575. 

Jankowski T, Livingstone DM, Blihrer H, Forster R, Niederhauser P (2006) Consequences of the 2003 European heat wave for lake temperature profiles, thermal stability, and hypolimnetic oxygen depletion implications for a warmer world. Limnol Oceanogr 51 815-819... 

Niimberg GK (2002) Quantification of oxygen depletion in lakes and reservoirs with the hypoxic factor. Lake Reserv Manage 18 299-306... 

The vibrational teiaperatnre does not change appreciably until we reach spectrum 10 in the sequence shown in Figure 1, i.e., until oxygen depletion has nearly stopped the reaction. Our crude estimate of the vibrational temperature based on the centroid position and the assumption that all vibrational temperature are the same suggests that the vibrational temperature, like the rotational teia-perature, falls below the surface temperature. This cannot be the case because the emission intensity would be too low to detect in our system if the asymmetric temperature were in fact that low. Our Interpretation 1 that symmetric stretch and bending have cooled to the point where they make very little contribution to the emission,... 

Figure 5.258. Dissolved oxygen profiles at time T = 1500 for three different floe sizes, all other conditions identical. Note how the larger floe becomes oxygen depleted at its centre. These results were replotted from the steady-state results.

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