This compound is relatively stable and has greater available chlorine than sodium hypochlorite liquid bleach. Calcium hypochlorite is a general oxidizing agent and therefore finds some use in organic chemistry. Calcium hypochlorite can also be used in the haloform reaction to manufacture chloroform. Sodium hypochlorite is most often encountered as a pale greenish-yellow dilute solution commonly known as liquid bleach or simply bleach , a household chemical widely used since the 18th century as a disinfectant or a bleaching agent.
The compound in solution is unstable and easily decomposes, liberating chlorine, which is the active principle of such products. Indeed, sodium hypochlorite is the oldest and still most important chlorine-based bleach. Sodium hypochlorite solutions have been used to treat dilute cyanide waste water, such as electroplating wastes.
In batch treatment operations, sodium hypochlorite has been used to treat more concentrated cyanide wastes, such as silver cyanide plating solutions. Sodium hypochlorite is commonly used as a biocide in industrial applications to control slime and bacteria formation in water systems used at power plants, pulp and paper mills, etc. A chlorine-dosing pump will add a carefully measured amount of diluted chlorine the chlorine is usually diluted using reverse osmosis water to the system as the water passes into a tank.
The amount of chlorine in the water needs to be monitored as the amount required for effective treatment will vary in line with the water quality. It is important that the level stays within the recommended limits, too little and not all the contaminants will be destroyed, too much is bad for human health. Chlorine is effective against almost all bacteria and viruses as well as algae, fungi, some minerals and man-made chemicals pollutants.
Water used for drinking and cooking should be free of pathogenic disease causing microorganisms that cause such illnesses as typhoid fever, dysentery, cholera, and gastroenteritis. Whether a person contracts these diseases from water depends on the type of pathogen, the number of organisms in the water density , the strength of the organism virulence , the volume of water ingested, and the susceptibility of the individual.
Purification of drinking water containing pathogenic microorganisms requires specific treatment called disinfection. Although several methods eliminate disease-causing microorganisms in water, chlorination is the most commonly used. Chlorination is effective against many pathogenic bacteria, but at normal dosage rates it does not kill all viruses, cysts, or worms. When combined with filtration, chlorination is an excellent way to disinfect drinking water supplies.
This fact sheet discusses the requirements of a disinfection system, how to test the biological quality of drinking water, how to calculate the amount of chlorine needed in a particular situation, chlorination equipment, by-products of disinfection, and alternative disinfection methods. A new pathogen screening test is Now Available. Disinfection reduces pathogenic microorganisms in the water to levels designated safe by public health standards.
This prevents the transmission of disease. An effective disinfection system kills or neutralizes all pathogens in the water.
It is automatic, simply maintained, safe, and inexpensive. An ideal system treats all the water and provides residual long-term disinfection. Chemicals should be easily stored and not make the water unpalatable. State and federal governments require public water supplies to be biologically safe. The U. Environmental Protection Agency EPA recently proposed expanded regulations to increase the protection provided by public water systems.
Water supply operators will be directed to disinfect and, if necessary, filter the water to prevent contamination from Giardia lamblia , Coliform Bacteria , Viruses , Heterotrophic Bacteria , Turbidity , and Legionella.
Private systems, while not federally regulated, are also vulnerable to biological contamination from sewage, improper well construction, and poor-quality water sources. Since more than 30 million people in the United States rely on private wells for drinking water, maintaining biologically safe water is a major concern.
The biological quality of drinking water is determined by tests for Total Coliform Bacteria. These organisms are found in the intestinal tract of warm-blooded animals and in the soil. Their presence in water indicates pathogenic contamination, but they are not considered to be pathogens. Public water systems are required to test regularly for Total Coliform Bacteria.
Private system testing is done at the owner's discretion. In an effective disinfected system, the values for free and total chlorine should be similar indicating all organic material and microorganisms in your water distribution system have been disinfected and that there is active chlorine in the water. Unlike most other Queensland drinking water supplies, Mt Crosby water is chloraminated, rather than chlorinated.
This means that some SEQ drinking water retailers are exclusively supplying chloraminated drinking water, some supply only chlorinated water while some supply chloraminated water for part of the year and chlorinated water at other times. If your facility is in SEQ, it is highly recommended you ask your drinking water service provider, which type of disinfectant is provided in your drinking water supply because this will affect any proposed chlorine dosing to be undertaken.
Chlorinating a chloraminated water distribution supply should be carefully considered, and if implemented, closely monitored.
This is because it may result in the production of the potentially harmful disinfection by-products, such as dichloramine and trichloramine and may also result in ineffective disinfection. For this reason chlorinating a chloraminated water distribution supply should only be undertaken by a qualified and appropriately licenced professional.
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