Chemical dosing systems (Swimming pools)
Introduction
Chlorination[1] is the procedure for disinfecting water using chlorine or chlorinated compounds. Chlorine gas can be used, but sodium hypochlorite (bleach) is normally used in tanks (Pivaque 1998) due to its greater ease of storage and dosage. In some cases, other chlorinated compounds are used, such as chlorine dioxide (ClO), calcium hypochlorite or chloroisocyanuric acid"). In 1908, waterborne diseases (cholera, typhoid fever, dysentery and hepatitis A) were eliminated in the United States.
History
In an article published in 1894, it was formally proposed to add chlorine to water to make it "germ-free." Two other authorities supported this proposal and published it in many other articles in 1895.[2] The first attempts to implement water chlorination in a water treatment plant were made in 1893 in Hamburg, Germany. In 1897, the town of Maidstone, England, was the first to treat its entire water supply with chlorine.[3].
Permanent water chlorination began in 1905, when a faulty slow sand filter and a contaminated water supply caused a severe typhoid epidemic in Lincoln, England. Alexander Cruickshank Houston used water chlorination to stop the epidemic. His installation fed the water to be treated with a concentrated solution of so-called chloride of lime. gas dissolved in lime water (diluted calcium hydroxide) to form calcium hypochlorite (chlorinated lime). Chlorination of the water supply helped stop the epidemic and, as a precaution, chlorination was continued until 1911, when a new water supply was brought into operation.[5]
The first continuous use of chlorine in the United States for disinfection occurred in 1908 at the Boonton Reservoir (on the Rockaway River), which served as a supply for Jersey City, New Jersey. Chlorination was achieved by controlled additions of dilute solutions of chloride of lime (calcium hypochlorite) at doses of 0.2 to 0.35 ppm. The treatment process was conceived by John L. Leal and chlorination plant was designed by George Warren Fuller").[7] In the following years, chlorine disinfection using chloride of lime (calcium hypochlorite) was rapidly implemented in drinking water systems around the world.[8].
The technique of purifying drinking water by using compressed liquefied chlorine gas was developed by a British officer in the Indian Medical Service"), Vincent B. Nesfield, in 1903. According to his own account: "It occurred to me that chlorine gas might prove satisfactory... if suitable means of using it could be found... The next important question was how to make the gas portable. This could be achieved in two ways: by liquefying it and storing it in iron vessels lined with lead, with a very fine capillary jet, and provided with a tap or screw cap, the tap is opened and the cylinder is placed in the "The necessary amount of water. The chlorine bubbles and in ten or fifteen minutes the water is absolutely safe. This method would be useful on a large scale, such as for service water carts."[9].