Chlorination
- Slovak term: Slovenský termín
- Chlorination is a chemical method for disinfecting water. Free chlorine inactivates pathogens in the water and provides a barrier against re-contamination (WHO 2004).
Explanation
Chlorination is the most commonly used drinking-water disinfection process, having demonstrated its effectiveness over nearly 100 years of use to inactivate microbial pathogens (with the notable exception of Cryptosporidium). Chlorination can be achieved by using liquefied chlorine gas, sodium hypochlorite solution, or calcium hypochlorite granules and on-site chlorine generators. Moreover, residual chlorine disinfection is used to provide a partial safeguard against low-level contamination and growth with the distribution system. While chlorine can react with organic matter to produce disinfection-by-products, risks to health from these by-products are extremely small in comparison to risks associated with in adequate disinfection, and it is important that disinfection should not be compromised to control such by-products. Chlorination acts as an oxidant and can remove or assist in the removal of some chemicals. At the household level, chlorination can be used as an emergency measure or as part of everyday life. When water quality cannot be trusted, a carefully measured amount of concentrated chlorine solution is added to a container with a known amount of clear water. The mixture is stirred and left for at least 30 minutes, to let the chlorine react and oxidize any organic matter in the water. After this, the water is safe to drink.
Example
“The results of these studies show conclusively that chlorination and storage of water in either a "safe" (specially designed) vessel or even a traditional vessel reduces diarrheal disease by about 20-48% and significantly improves the microbial quality of water (by reducing thermotolerant (or fecal) coliforms, E. coli, V. cholerae and other microbial contaminants)."
References
- WHO (2004), Water treatment and pathogen control: process efficiency in achieving safe drinking-water
- WHO (2004) Guidelines for Drinking-water Quality
- WHO (2002), Managing water in the home: accelerated health gains from improved water supply
- Brikké F and Bredero M (2003) Linking technology choice with operation and maintenance in the context of community water supply and sanitation: A reference document for planners and project staff
- Parr J, Smith M, Shaw R (1995) Chlorination of community water supplies. Waterlines,
- 14(2):15–18 (Technical Brief, No. 46).
- White GC (1986) The handbook of chlorination, 2nd ed. New York, Van Nostrand Reinhold.
