Oxygen, Oxidants, and Reductants

Oxygen is a vitally important species in water (see Chapter 3). In water, oxygen is consumed rapidly by the oxidation of organic matter, CH2O  

Unless the water is reaerated efficiently, as by turbulent flow in a shallow stream, it rapidly loses oxygen and will not support higher forms of aquatic life. 

In addition to the microorganism-mediated oxidation of organic matter, oxygen in water may be consumed by the biooxidation of nitrogenous material 

Although BOD is a reasonably realistic measure of water quality insofar as oxygen is concerned, the test for determining it is time-consuming and cumbersome to perform. Total organic carbon (TOC) is frequently measured by catalytically oxidizing carbon in the water and measuring the CO2 that is evolved. It has become a popular test in place of BOD because TOC is readily determined instrumentally. 

FIGURE 4.4 Oxygen sag curve resulting from the addition of oxidizable pollutant material to a stream. 

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Korzhinskii, D.S. 1963. Correlation between activity of oxygen, oxidity and reduction potential in endogenic mineral formation. Izvestiya of Academy of Sciences of USSR. Geological seria. No. 3. 54-61. (In Russian)... 

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