The Importance Of Biochemical Oxygen Demand (BOD) In The Water Analysis Sector

A high standard of living involves a high demand for water and, at the same time, causes much greater pollution of this essential element for life. The resultant interference in the natural cycle can often overwhelm natural processes of recovery, so that, in addition to products arising from the decomposition of natural substances (e.g., proteins, greases, carbohydrates) there is a build-up of anthropogenous additives such as pesticides, effluents and garbage, which contaminate drinking water supplies with their toxic or hormonal effects. They may also consume such large quantities of oxygen that water resources become fouled. To prevent the threat of possible danger to health, or the very existence of certain species, it is essential to determine the quality of a water source before water is drawn off for consumption.

Water quality is dependent on its constituents, which can be divided into organic and inorganic substances. Given the wide range of natural and synthetic compounds which exist, an analysis of the individual constituents is not a practical proposition and, in any case, a complex affair. In practice, in order to arrive at significant milestones which will permit an evaluation of water quality, rapid methods of analysis are used which consider groups of parameters, rather than the individual parameters themselves. In this connection, BOD is employed to determine the aerobic destructibility of organic substances. As long ago as 1870, Frankland carried out the first BOD measurements, which were very similar to the dilution method in use today.