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Chlorine (NaDCC)

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Chlorine began to be widely used as a disinfectant in the early 1900’s. It revolutionized drinking water treatment and dramatically reduced the incidence of waterborne diseases. Chlorine remains the most widely used chemical for water disinfection in the United States.
NaDCC, also known as sodium dichloroisocyanurate or sodium troclosene, is one form of chlorine used for disinfection. It is often used to treat water in emergencies, and is now widely available for household water treatment.
NaDCC tablets are available with different chlorine content (e.g. 3.5 mg to 10 g) to treat from 1 to 3000 litres at a time. They are usually effervescent (meaning that escaping carbondioxide gas causes the tablets to dissolve quickly, with a 'fizz'), allowing the tablet to dissolve in less than 1 minute.
 
When added to water, NaDCC releases hydrochloric acid which reacts through oxidization with microorganisms and kills them.
 
Three things can happen when chlorine is added to water:
 
# Some chlorine reacts through oxidization with organic matter and the pathogens in the water and kills them. This portion is called consumed chlorine.
# Some chlorine reacts with other organic matter and forms new chlorine compounds. This portion is called combined chlorine.
# Excess chlorine that is not consumed or combined remains in the water. This portion is called free residual chlorine (FRC). The FRC helps prevent recontamination of the treated water.
 
==History and social context==
 
==Suitable conditions ==
Unlimited amounts of water can be processed at a time, depending on the amount of active chlorine.
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==What is a NaDCC?Technical specification== ====Operation====Chlorine began Each product should have its own instructions for correct dosing. In general, the user adds the correct sized tablet for the amount of water to be widely used as a disinfectant in treated, following the early 1900’sproduct instructions. It revolutionized drinking water treatment Then they agitate the container, and dramatically reduced wait for the incidence amount of waterborne diseasestime instructed on the package, normally 30 minutes (“contact time”). Chlorine remains the most widely The water is then disinfected and ready to be used chemical for water disinfection in the United States.NaDCC, also known as sodium dichloroisocyanurate or sodium troclosene, is one form The effectiveness of chlorine used for disinfection. It is often used to treat water in emergenciesaffected by turbidity, organic matter, temperature and is now widely available for household pH. For high turbidity levels, the water treatmentshould first be strained through a cloth or be sedimented before adding chlorine. These processes will remove some of the suspended particles and improve the reaction between the chlorine and pathogens. NaDCC tablets are available The manufacturer’s instructions for specific sodium hypochlorite products need to be followed. The required dose and contact time varies with different chlorine content water quality (e.g. 3.5 mg to 10 g) to treat from 1 to 3000 litres at a time. They are usually effervescent (meaning that escaping carbondioxide gas causes the tablets to dissolve quicklyturbidity, pH, with a 'fizz'temperature), allowing the tablet to dissolve in less than 1 minute.
==How Does It Remove Contamination?==When added to waterUse a 30 minute minimum contact time. If the pH is above 7.5, NaDCC releases hydrochloric acid which reacts through oxidization with microorganisms a higher Free Residual Clorine concentration of 0.6 mg/litre should be used and kills themthe contact time should be extended to 1 hour.
Three things can happen The contact time should be increased to 1 hour when chlorine the temperature is added between 10˚ and 18˚C. It should be increased to water:two or more hours when the temperature falls below 10˚C.
# Some chlorine reacts through oxidization with organic matter and the pathogens in the water and kills them. This portion is called consumed chlorine.# Some chlorine reacts with other organic matter and forms new chlorine compounds. This portion is called combined chlorine.# Excess chlorine that is not consumed or combined remains in the water. This portion is called free residual chlorine (FRC)Manufacturer’s instructions for specific NaDCC products need to be followed. The FRC helps prevent recontamination batch volume depends on size of the treated watercontainer used by the household.
==Operation==Each product should have its own instructions for correct dosingRequired dose and contact time varies with water quality (e. In general, the user adds the correct sized tablet for the amount of water to be treated, following the product instructionsg. Then they agitate the containerturbidity, and wait for the amount of time instructed on the packagepH, normally 30 minutes (“contact time”temperature). The water is then disinfected and ready minimum contact time to be usedneeded is 30 minutes.
The effectiveness of Free residual chlorine is affected by turbidity, organic matter, temperature and pH. For high turbidity levels, the water should first be strained through a cloth or be sedimented before adding chlorine. These processes will remove some of the suspended particles and improve the reaction between the chlorine and pathogensprotects against recontamination.
Most users cannot determine the dosing quantity themselves; proper use requires simple instructions from the manufacturer. Users often use less than the recommended dose to save money.
====Treatment efficiencyEfficiency====
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Toxoplasma oocysts and cryptosporidium oocysts are highly resistant to chlorine disinfection <ref name=cdcp07/>. Chlorine alone should not be expected to inactivate these pathogens in drinking water.
==Operating criteria==*'''Flow rate:''' Not applicable*'''Batch volume:''' Unlimited*'''Daily Some NaDCC products claim that there is no bad odour or taste after use. Chlorine reacts with organic matter naturally present in water supply:''' Unlimited to form by-products such as trihalomethanes (THMs), which are potentially cancer-causing. Lantagne et al. (2008)<ref>[[#lantagne08|Lantagne et al. (2008)]]</ref> indicate that THM levels produced during household chlorination may fall below World Health Organization (WHO) guideline values.
The manufacturer’s instructions for specific sodium hypochlorite products need to be followed====Maintenance====Chlorine requires a supply chain, market availability and regular purchase. The required dose and contact time varies with water It also requires quality (econtrol process to ensure product reliability.g. turbidity, pH, temperature)Sourcing suitable plastic containers to manufacture chlorine solutions can sometimes be a challenge.
Use a 30 minute minimum contact time. If the pH is above 7.5, a higher Free Residual Clorine concentration of 0.6 mg/litre Products should be used and the contact time should be extended protected from exposure to 1 hourtemperature extremes or high humidity.
The contact time should ====Manufacturing====NaDCC tablets cannot be increased to 1 hour when the temperature is between 10˚ produced locally, but they can be bought in bulk and 18˚C. It should be increased to two or more hours when the temperature falls below 10˚Cpackaged locally.
Manufacturer’s instructions Materials and facilities required are simply the tablets and packaging materials. Workshop space is required for specific NaDCC products need to be followed. The batch volume depends on size of the container used by packaging the householdtablets.
Required dose and contact time varies with water quality (e.g. turbidity, pH, temperature). The minimum contact time to Anyone can be needed is 30 minutes.  ==Robustness==Free residual chlorine protects against recontaminationtrained for light packaging work.
Most users cannot determine the dosing quantity themselves; proper use requires simple NaDCC tablets do not contain hazardous chemicals, they are safe to handle and store. Manufacturer’s instructions from the manufacturer. Users often use less than the recommended dose to save moneyshould be followed.
Chlorine requires a supply chain, market availability and regular purchase. It also requires quality control process to ensure product reliability. Sourcing suitable plastic containers to manufacture chlorine solutions can sometimes be a challenge.  ====Estimated lifespanLifespan====
Chlorine deteriorates over time, especially in liquid form. Liquid chlorine products should be used within 3 months of being manufactured.
If stored in strip packs, the product has a shelf-life of five years. If stored in tubs, it has a three year shelf-life.
==Manufacturing requirements== =====Worldwide producers=Suppliers====Medentech Ltd. manufactures Aquatabs for water disinfection, hospital surface infection control and general environmental disinfection.  =====Local production=====NaDCC tablets cannot be produced locally, but they can be bought in bulk and packaged locally.  =====Materials and facilities=====Tablets and packaging materials =====Fabrication Facilities=====Workshop space is required for packaging the tablets.  =====Labour=====Anyone can be trained for light packaging work.  =====Hazards=====NaDCC tablets do not contain hazardous chemicals, they are safe to handle and store. Manufacturer’s instructions should be followed.  ==Maintenance requirements==Products should be protected from exposure to temperature extremes or high humidity.
==Cost==
Note: Program, transportation and education costs are not included.
==OtherCountry experiences==Some NaDCC products claim that there is no bad odour or taste after use. Chlorine reacts with organic matter naturally present in water to form by-products such as trihalomethanes (THMs), which are potentially cancer-causing. Lantagne et al. (2008)<ref>[[#lantagne08|Lantagne et al. (2008)]]</ref> indicate that THM levels produced during household chlorination may fall below World Health Organization (WHO) guideline values. ==Manuals==
==Movies==
==External linksLinks==
*[http://www.cawst.org CAWST (Centre for Affordable Water and Sanitation Technology)]
* [http://www.aquatabs.com Aquatabs]
* [http://www.medentech.com Medentech Ltd.]
 
==Footnotes==
<references/>
==Acknowledgements==
This article is based on a factsheet from [http://www.cawst.org/ Centre for Affordable Water and Sanitation Technology (CAWST)], which is gratefully acknowledged.
 
==Footnotes==
<references/>
==References==
 
* Clasen, T. and P. Edmondson (2006). Sodium dichloroisocyanurate (NaDCC) tablets as an alternative to sodium hypochlorite for the routine treatment of drinking water at the household level. International Journal of Hygiene and Environmental Health Volume 209, Issue 2, pp. 173-181.
* Clasen, T., Saed, T., Boisson, S., Edmondson, P., and O. Shipin. (2007). Household Water Treatment Using Sodium Dichloroisocyanurate (NaDCC) Tablets: A Randomized, Controlled Trial to Assess Microbiological Effectiveness in Bangladesh. Am. J. Trop. Med. Hyg., 76(1), 2007, pp. 187–192.
* Lantagne, D.S., Blount, B. C., Cardinali, F., and R. Quick, R (2008). Disinfection by-product formation and mitigation strategies in point-of-use chlorination of turbid and non-turbid waters in western Kenya. Journal of Water and Health, 06.1, 2008.
* Molla, N., (2007). Practical Household Use of the Aquatabs Disinfectant for Drinking Water Treatment in the Low-Income Urban Communities of Dhaka, Bangladesh. Thesis, Asia Institute of Technology, School of Environment, Resources and Development.
 
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