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Impact of Water Chlorination
The use of water chlorination to disinfect public water supplies, which began in the early 1900s, has had major impacts on the incidence of waterborne disease in the U.S. and worldwide. Christman of the Chlorine Chemistry Council1, credits filtration and chlorination of drinking water with responsibility for a large part of the 50 % increase in life expectancy that has occurred in developed countries during the twentieth century. He also notes that Life magazine recently cited drinking water chlorination and filtration as one of the most significant public health advances of the millennium.
The U.S. EPA in an article on the history of water treatment2, noted that the use of drinking water chlorination, beginning in the early 1900s, led to a dramatic decrease in the incidence of waterborne diseases like typhoid, cholera, and dysentery. For example, typhoid fever in the U.S. dropped from an incidence of about 100 per 100,000 in 1900 to 33.8 per 100,000 in 19203, and to 0.1 per 100,000 in 20064.
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The Handbook of Chlorination
An authoritative reference that contains almost anything you want to know about water chlorination is the "Handbook of Chlorination and Alternative Disinfectants" by George Clifford White. The 1998, 4th Edition is the last version written by George Clifford White. A 2010 update, "White's Handbook of Chlorination and Alternative Disinfectants," written by Black and Veatch, is now also available. Both of these 1000+ page books are a wealth of information about drinking water chlorination systems, including the history of water chlorination.
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The History of Water Chlorination before 1900
Although most of the developments in the use of chlorine as a water supply disinfectant took place after 1900, a few noteworthy events in the use of chlorine as a disinfectant prior to 1900 are as follows:1, 5, 6
- 1846 - Dr. Ignaz Semmelweis instituted a requirement for physicians at a Vienna Hospital to wash their hands with soap and chlorine water to reduce infections and child bed fever in patients.
- 1854 - Dr. John Snow used chlorine in an attempt to disinfect the Broad Street Pump water supply in London, which he had identified as a cause of a cholera outbreak due to sewage contamination.
- 1879 - William Soper of England used chlorinated lime to treat the feces of typhoid patients before disposal into the sewer.
- 1893 - Chlorine was used on a plant scale basis for drinking water disinfection in Hamburg, Germany.
- 1897 - Sims Woodhead temporarily sterilized the potable water distribution mains at Maidstone, Kent, in England, using a bleach solution.
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The History of Water Chlorination in the early 1900s
- 1903 - The first use of chlorine gas for disinfection of drinking water in Middlekerke, Belgium. (Previous chlorination was with hydrated lime, chloride of lime or bleaching powder.)
- 1908 - The water utility in Jersey City, NJ became the first in the U.S. to use full scale water chlorination, using sodium hypochlorite. Dr. John Leal, a chemist, and George Warren Fuller, an engineer, conceived and designed the water chlorination system that was put into use in Jersey City, NJ.
- 1908 - At the Union Stockyards in Chicago, IL, the Bubbly Creek Filter Plant began chlorination of their water supply using chloride of lime.
- 1910 - In Youngstown, Ohio, C. R. Darnall was the first to use compressed chlorine gas from a steel cylinder for a water chlorination system. This is the most common method in use for water chlorination today.
- 1914 - The U.S. Department of the Treasury enacted a set of standards calling for a maximum bacterial concentration of 2 coliforms per 100 ml in drinking water, effectively requiring drinking water disinfection and leading to a dramatic increase in the use of drinking water chlorination by treatment plants.
- 1920s - 1930s - Drinking water filtration and chlorination had virtually eliminated epidemics of waterborne diseases in the U.S.
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Water Chlorination Concerns
Although there was some opposition to water chlorination, perhaps due to effects on the taste of early chlorinated water, the positive public health effects were so apparent that the use of water chlorination spread rapidly after its first U.S. use in Jersey City and Chicago.
Beginning in the 1970s, the presences of disinfection byproducts (DBPs) formed by reaction of chlorine with other compounds in the water was noted and possible health effects of DBPs were investigated. This led to the first DBP rule in 1979. U.S. EPA set an interim maximum contaminant level of 0.10 mg/L for trihalomethanes. As additional knowledge about DBPs was gained, a Stage 1 Disinfectants and Disinfection Byproducts Rule was issued in 1998, and a Stage 2 Disinfectants and Disinfection Byproducts Rule was issued in 2006. More information is available from U.S. EPA8.
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References and Image Credits
1. Christman, K.A., Chlorine, Chlorine Chemistry Council, Arlington, VA, USA, Available at http://www.cepis.org.pe/eswww/caliagua/simposio/enwww/ponencia/ponen8.doc
2. US Environmental Protection Agency. The history of drinking water treatment. Available at http://www.epa.gov/safewater/consumer/pdf/hist.pdf
3. Centers for Disease Control and Prevention. Achievements in public health, 1900–1999: safer and healthier foods. MMWR 1999; 48(40): 905.
4. Centers for Disease Control and Prevention. Summary of notifiable diseases- United States, 2006. MMWR 2008; 55(53): 17.
5. Hall, E.L, and Dietrich, A.M., A Brief History of Drinking Water, Rhode Island Water Resources Board, Available at http://www.wrb.state.ri.us/program_eohistory.html
6. Curtis, M. and Johnston, E., Chlorine Disinfection, Civil Engineering Department, Virginia Tech, Available at http://www.cee.vt.edu/ewr/environmental/teach/wtprimer/chlorine/chlorine.html
7. The American Chemistry Council's Chlorine Chemistry Division, A Giant Step for Public Health: Chlorination in Chicago & Jersey City, Available at http://www.americanchemistry.com/100years/CityHistory.pdf
8. US Environmental Protection Agency. Microbial and Disinfection Byproduct (MDBP) Rules. Available at http://pubweb.epa.gov/ogwdw/mdbp/mdbp.html#trihalomethanes
9. Image of a water tap: http://www.flickr.com/photos/julien_harneis/589759829/
10. Image of a glass of water: http://www.flickr.com/photos/malias/45580483/