Oxygen utilization

The amount of oxygen used in the degradation process is called the biochemical oxygen demand (BOD). A standard test has been devised to measure BOD in which the oxygen utilized by microorganisms in contact with the wastewater over a 5-day period at 20°C is measured. 

It may be denitrihed. This happens when microbes hungry for oxygen utilize... 

J-C Marchon, T Mashiko, CA Reed. How does nature control cytochrome redox potentials In C Ho, ed. Electron Transport and Oxygen Utilization. New York Elsevier North-Holland, 1982, pp 67-72. 

RR Respiration rate - the weight of oxygen utilized by the total weight of MLSS in a given time. 

Oxygen uptake rate (OUR) The actual rate at which oxygen utilization takes place and is given by ( o/Yo2) C, , where p is specific growth... 

Fig. 10-15 Organic carbon fluxes with depth in the water column normalized to mean annual primary production rates at the sites of sediment trap deployment. The undulating line indicates the base of the euphotic zone the horizontal error bars reflect variations in mean annual productivity as well as replicate flux measurements during the same season or over several seasons vertical error bars are depth ranges of several sediment trap deployments and uncertainities in the exact depth location. (Reproduced with permission from E. Suess (1980). Particulate organic carbon flux in the oceans - surface productivity and oxygen utilization, Nature 288 260-263, Macmillan Magazines.)...

The key to imderstanding these remineralization reactions is the parameter Apparent Oxygen Utilization (AOU), defined as... 

Suess, E. (1980). Particulate organic carbon flux in the oceans-surface productivity and oxygen utilization. Nature 288, 260-263. 

Carbon monoxide cyanogen, hydrogen cyanide nitrites arsine aniline, dimethyl aniline, toluidine nitrobenzene hydrogen sulphide (causes respiratory paralysis by impairment of oxygen utilization in the central nervous system). 

As stated in section 5.1.1, some bacteria derive energy from food sources without the use of oxygen, whereas others are able to use this gas. The pathway of oxygen utilization itself is also a stepwise series of reactions and thus the overall picture emerges of cellular metabolism characterized by multistep reactions. 

Perlmutter JS, Powers WJ, Herscovitch R Fox PT, Raichle ME. Regional asymmetries of cerebral blood flow, blood volume, and oxygen utilization and extraction in normal subjects. J Cereb Blood Flow Metab 1987 7 64-67. 

Oxygen-utilizing organisms have generally evolved specific enzyme-mediated systems that serve to protect the cell from such reactive species. These enzymes include SOD and catalase or glutathione peroxidase (GSH-px), which catalyse the following reactions ... 

Acrolein was the most toxic of 15 herbicides tested for toxicity to fish (USEPA 1980). Responses by rainbow trout (Oncorhynchus mykiss) surviving 77 pg acrolein/L, a concentration that killed 50% in about 21 h, were characteristic of respiratory irritants (McKim et al. 1987). These responses included a steady increase in cough rate decreases in ventilation rate, oxygen utilization, and heart... 

While the above discussion describes testing of aerobic microbial activity, the same scenario is applicable for anaerobic bioreactions. The primary difference is the analytical parameter. The uptake of carbon dioxide, nitrate degradation, sulfate reduction, or iron reduction may be monitored instead of oxygen utilization. 

Both Kalckar and the Russians measured the ratio of atoms of phosphorus yielding ATP to the atoms of oxygen utilized (P/O ratio) and found values significantly greater than 1, the figure expected if a phosphate group had been introduced into a cycle intermediate, as in the glycolytic pathway. 

Leonardo da Vinci. Animals unable to survive in an atmosphere that did not support combustion. van Leeuwenhoek. Lenses used to examine bacteria. Laviosier and Laplace. Amount oxygen utilized by guinea pigs directly proportional to their energy (heat) production... 

The rate of oxygen utilization is related to the intrinsic rate of carbon burning by the ratio of CO to CO2 produced in the burning reaction. This relation can be expressed in terms of a constant a that is defined as the moles of coke burned per mole of O2 consumed, and varies between 1 and 2. The relation between the two rates is given by... 

The rate of oxygen utilization (/ ) is given by the rate of diffusion of oxygen across the exterior surface of the bead. 

Low utilizations, particularly oxygen utilization, yield high performance. Low utilizations, however, result in poor fuel use. Optimization of this parameter is required. State-of-the-art utilizations are on the order of 85% and 50% for the fuel and oxidant, respectively. 

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