Disinfection germicidal range

A pH range of 5.5 to 8.5 and a temperature range of 45 to 110°F is required. The bacteria require at least 10 parts per million (ppm) nitrogen and 5 ppm phosphorus. The optimum bioremediation will occur between 3 and 5 mg/liter dissolved oxygen. Extreme salinity, strong acids, caustics, disinfectants, germicides, and chlorine may limit the activity or kill the bacteria. 

Absorption of UV-C radiation by cellular constituents of organisms may lead to severe cell mutations and cell death. Therefore, this wavelength band is often called the germicidal range. It is used in UV disinfection processes to inactivate bacteria, viruses and other microorganisms (cf Chapter 9). At the Earths surface sunlight contains no VUV and UV-C radiation because of their efficient absorp-... 

Phenol has a wide range of uses, including in the preparation of phenolic and epoxy resins (bisphenol-A), nylon-6 (caprolactam), 2,4-D, selective solvents for refining lubricating oils, adipic acid, salicylic acid, phenolphthalein, pentachlorophenol and other derivatives in germicidal paints as a laboratory reagent and in dyes and indicators and as a slimicide, biocide and general disinfectant (Lewis, 1993). The world demand for phenol by use in 1993 was reported as (%) phenolic resins, 35 bisphenol-A, 30 caprolactam, 15 alkylphenols, 7 aniline, 5 and others, 8 (Wallace, 1996). 

Sterilization. Certain ranges of ultraviolet rays can kill bacteria. This property is used in sterilizing water, milk and other foodstuffs, and medicinal facilities and equipment. Also, modern food and drug plants often use germicidal lamps to disinfect their products and the containers. 

Other Cresol-type Disinfectants and Antiseptics. Various non-irritant germicides of low toxicity, and therefore particularly suitable for disinfecting the skin and for application to wounds, contain different amounts of chloroxylenol, dichloroxylenol, benzyl cresols, o-phenylphenol, chloro-benzylphenols, special narrow-range boiling fractions of coal tar distillates, etc. They are usually dissolved in a soap, such as castor oil soap, and essential oil solution as they are only sparingly soluble in water. The various phenol coefficient tests, and particularly the Chick-Martin test, are of value in standardising such preparations, but they are of little value in determining their practical efficacy as antiseptics. For such purposes, other more specific tests are required which are beyond the scope of this book. 

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