Water is the universal solvent. Many compounds that can dissolve in water are used as food sources by a variety of microbiological life forms. These microorganisms are themselves water-based and their constituent molecules are designed to function in aqueous environments. Thus, water can widely support the growth of microorganisms.

Some of this growth is advantageous. For example, the strains of yeast whose fermentative abilities make possible the brewing of beer, the production of wine, and the baking of bread. In addition, the growth of bacteria in polluted water is used as a means of decontaminating the water. The bacteria are able to use the pollutant compound as a food source. In contrast, some forms of microbial growth can detrimental to products being produced or dangerous to the health of people consuming the water. Ensuring the quality of water from a microbiological standpoint is thus of extreme...