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APHA color is a color scale sometimes referred to as a "yellowness index" that is used to assess the quality of liquids that are clear to yellowish in color. It is similar to the Hazen color test, to which it is sometimes incorrectly referred. The Hazen color test uses a Pt/Co solution and was developed for water treatment facilities where the ...
Pt/Co scale. The Platinum-Cobalt Scale (Pt/Co scale or Apha-Hazen Scale ) is a color scale that was introduced in 1892 by chemist Allen Hazen (1869–1930). The index was developed as a way to evaluate pollution levels in waste water. It has since expanded to a common method of comparison of the intensity of yellow-tinted samples.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable ...
Advanced oxidation processes (AOPs), in a broad sense, are a set of chemical treatment procedures designed to remove organic (and sometimes inorganic) materials in water and wastewater by oxidation through reactions with hydroxyl radicals (·OH). [1] In real-world applications of wastewater treatment, however, this term usually refers more ...
Topsoil runoff from farm, central Iowa (2011). Water pollution in the United States is a growing problem that became critical in the 19th century with the development of mechanized agriculture, mining, and industry, although laws and regulations introduced in the late 20th century have improved water quality in many water bodies. [1]
Drinking water standards include lists of parametric values, and also specify the sampling location, sampling methods, sampling frequency, analytical methods, and laboratory accreditation (AQC). In addition, a number of standards documents also require calculation to determine whether a level exceeds the standard, such as taking an average.
Water softening is the removal of calcium, magnesium, and certain other metal cations in hard water. The resulting soft water requires less soap for the same cleaning effort, as soap is not wasted bonding with calcium ions. Soft water also extends the lifetime of plumbing by reducing or eliminating scale build-up in pipes and fittings.
Sedimentation (water treatment) The physical process of sedimentation (the act of depositing sediment) has applications in water treatment, whereby gravity acts to remove suspended solids from water. [1] Solid particles entrained by the turbulence of moving water may be removed naturally by sedimentation in the still water of lakes and oceans.