Chloramination is the treatment of

drinking water Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, ...

with a chloramine

disinfectant A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than s ...

. Both

chlorine Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is ...

and small amounts of

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogeno ...

are added to the water one at a time which react together to form chloramine (also called combined chlorine), a long lasting

. Chloramine disinfection is used in both small and large water treatment plants.

Use

In the United States, the maintenance of what is called a "residual" of disinfectant that stays in the

water distribution system A water distribution system is a part of water supply network with components that carry potable water from a centralized treatment plant or wells to consumers to satisfy residential, commercial, industrial and fire fighting requirements. Defini ...

while it is delivered to people's homes is required by the

Environmental Protection Agency A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...

(EPA). The EPA regulations give two choices for disinfectant residual — chlorine or chloramine. Many major water agencies are changing to chloramine to better meet current and anticipated federal drinking water regulations and to protect the

public health Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...

Chlorine versus chloramine

There are many similarities between chlorine and chloramine. Both provide effective residual disinfection with minimal risk to public health. Both are

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

and

amphibians Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arb ...

. Both chlorine and chloramine react with other compounds in the water to form what are called "disinfection byproducts". The difference is that chlorine forms many byproducts, including

trihalomethane In chemistry, trihalomethanes (THMs) are chemical compounds in which three of the four hydrogen atoms of methane () are replaced by halogen atoms. Many trihalomethanes find uses in industry as solvents or refrigerants. THMs are also environm ...

s (THM) and

haloacetic acids Haloacetic acids are carboxylic acids in which a halogen atom takes the place of a hydrogen atom in acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formul ...

(HAA), whereas chloramine forms a significantly lower amount of THMs and HAAs but also forms ''N''-nitrosodimethylamine (NDMA). One of the principal benefits of chloramine is that its use reduces the overall levels of these regulated contaminants compared to chlorine.

Adverse effects

Chloramine is toxic to fish and amphibians. Chloramine, like chlorine, comes in direct contact with their bloodstream through fish

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

and must be removed from water added to aquariums and fish ponds. It must also be removed from water prior to use in

dialysis Dialysis may refer to: *Dialysis (chemistry), a process of separating molecules in solution **Electrodialysis, used to transport salt ions from one solution to another through an ion-exchange membrane under the influence of an applied electric pote ...

machines, since water comes into direct contact with the bloodstream during treatment. Since the 1980s, most dialysis machines are built with filters to remove chloramines. Chloramine is generally considered a problem in

brewing Brewing is the production of beer by steeping a starch source (commonly cereal grains, the most popular of which is barley) in water and fermenting the resulting sweet liquid with yeast. It may be done in a brewery by a commercial brewer, ...

beer; like chlorine it can react with and change some of the natural plant flavors that make up the beer, and it may slow or alter the yeast. Because chloramine dissipates much more slowly than chlorine from water, beer-makers prefer carbon filtration and / or Campden tablets to neutralize it in the water. People have no trouble digesting chlorine or chloramine at the levels found in public drinking water; this water is not introduced directly into the human bloodstream. In the United States, the

United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it ...

set minimum and maximum health-based safe levels for chloramine in drinking water. Elsewhere, similar oversight agencies may set drinking water quality standards for chloramine. Two home builders filed lawsuits against Moulton Niguel Water District in 2012, (in Orange County CA), arguing that pinhole leaks in copper water piping in their homes was due to faulty water treatment with chloramine. Pinhole leaks cause expensive damage to people's homes, and the builders claim that they must repipe houses at great expense to deal with the problem. Officials observed that only the two builders have filed suit, but as of late 2013 the number of lawsuits had expanded. Nitrogenous

disinfection by-product Disinfection by-products (DBPs) result from chemical reactions between organic and inorganic matter in water with chemical treatment agents during the water disinfection process. Chlorination disinfection byproducts Chlorinated disinfection age ...

s are liable to convert to nitrosamines by the action of chlorination and chloramination. Other NDBPs include halonitroalkanes, halonitriles, and haloamides.

Removing monochloramine from water

Chloramines should be removed from water for

, aquariums,

hydroponic Hydroponics is a type of horticulture and a subset of hydroculture which involves growing plants, usually crops or medicinal plants, without soil, by using water-based mineral nutrient solutions in aqueous solvents. Terrestrial or aquatic plan ...

applications, and homebrewing beer.. Chloramine must be removed from water prior to use in kidney dialysis machines because it can cause hemolytic anemia if it enters the blood stream. In hydroponic applications, chloramine stunts the growth of plants. When a chemical or biological process that changes the chemistry of chloramines is used, it falls under reductive dechlorination. Other techniques use physical—not chemical—methods for removing chloramines.

Ultraviolet light

The use of

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiati ...

light for chlorine or chloramine removal is an established technology that has been widely accepted in pharmaceutical, beverage, and dialysis applications. UV is also used for disinfection at aquatic facilities.

Ascorbic acid and sodium ascorbate

Ascorbic acid Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) a ...

(vitamin C) and

sodium ascorbate Sodium ascorbate is one of a number of mineral salts of ascorbic acid (vitamin C). The molecular formula of this chemical compound is C6H7NaO6. As the sodium salt of ascorbic acid, it is known as a mineral ascorbate. It has not been demonstrate ...

completely neutralize both

and chloramine, but degrade in a day or two, which makes them usable only for short-term applications. SFPUC determined that 1000 mg of

vitamin C Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) a ...

tablets, crushed and mixed in with bath water, completely remove chloramine in a medium-size bathtub without significantly depressing pH.

Activated carbon

Activated carbon Activated carbon, also called activated charcoal, is a form of carbon commonly used to filter contaminants from water and air, among many other uses. It is processed (activated) to have small, low-volume pores that increase the surface area avail ...

has been used for chloramine removal long before catalytic

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes ...

, a form of activated carbon, became available; standard activated carbon requires a very long contact time, which means a large volume of carbon is needed. For thorough removal, up to four times the contact time of catalytic carbon may be required. Most

units now depend on

granular activated carbon Activated carbon, also called activated charcoal, is a form of carbon commonly used to filter contaminants from water and air, among many other uses. It is processed (activated) to have small, low-volume pores that increase the surface area avail ...

(GAC) filters, two of which should be placed in series so that chloramine breakthrough can be detected after the first one, before the second one fails. Additionally,

sodium metabisulfite Sodium metabisulfite or sodium pyrosulfite (IUPAC spelling; Br. E. sodium metabisulphite or sodium pyrosulphite) is an inorganic compound of chemical formula Na2S2O5. The substance is sometimes referred to as disodium metabisulfite. It is used a ...

injection may be used in certain circumstances.

Campden tablets

Home brewers use reducing agents such as sodium metabisulfite or potassium metabisulfite (both proprietorially sold as Campden tablets) to remove chloramine from brewing

fermented beverages This is a list of fermented foods, which are foods produced or preserved by the action of microorganisms. In this context, Fermentation in food processing, fermentation typically refers to the fermentation of sugar to ethanol, alcohol using yeas ...

. However, residual sulfite can cause off flavors in beer so potassium metabisulfite is preferred.

Sodium thiosulfate

Sodium thiosulfate is used to dechlorinate

tapwater Tap water (also known as faucet water, running water, or municipal water) is water supplied through a tap, a water dispenser valve. In many countries, tap water usually has the quality of drinking water. Tap water is commonly used for drinking, ...

for aquariums or treat effluent from wastewater treatments prior to release into rivers. The reduction reaction is analogous to the iodine reduction reaction. Treatment of tapwater requires between 0.1 and 0.3 grams of pentahydrated (crystalline) sodium thiosulfate per 10 L of water. Many animals are sensitive to chloramine, and it must be removed from water given to many animals in zoos.

Other methods

Chloramine, like chlorine, can be removed by boiling and aging. However, time required to remove chloramine is much longer than that of chlorine. The time required to remove half of the chloramine (

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...

) from of water by boiling is 26.6 minutes, whereas the half-life of free chlorine in boiling 10 gallons of water is only 1.8 minutes. Aging may take weeks to remove chloramines, whereas chlorine disappears in a few days.

References

{{Reflist

External links

Chloramines in Drinking Water
at

EPA The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...

Citizens Concerned About Chloramine (CCAC)
Water treatment Chlorine