Water purification - Knowledge (XXG)

693: 1598: 1140: 1757: 720:, on the surface of the filter. An effective slow sand filter may remain in service for many weeks or even months, if the pretreatment is well designed, and produces water with a very low available nutrient level which physical methods of treatment rarely achieve. Very low nutrient levels allow water to be safely sent through distribution systems with very low disinfectant levels, thereby reducing consumer irritation over offensive levels of chlorine and chlorine by-products. Slow sand filters are not backwashed; they are maintained by having the top layer of sand scraped off when the flow is eventually obstructed by biological growth. 289: 1731:, and other minerals in water can help to protect against nutritional deficiency. Demineralized water may also increase the risk from toxic metals because it more readily leaches materials from piping like lead and cadmium, which is prevented by dissolved minerals such as calcium and magnesium. Low-mineral water has been implicated in specific cases of lead poisoning in infants, when lead from pipes leached at especially high rates into the water. Recommendations for magnesium have been put at a minimum of 10 mg/L with 20–30 mg/L optimum; for calcium a 20 mg/L minimum and a 40–80 mg/L optimum, and a total 543:

litres per square meter per hour). In general, sedimentation basin efficiency is not a function of detention time or depth of the basin. Although, basin depth must be sufficient so that water currents do not disturb the sludge and settled particle interactions are promoted. As particle concentrations in the settled water increase near the sludge surface on the bottom of the tank, settling velocities can increase due to collisions and agglomeration of particles. Typical detention times for sedimentation vary from 1.5 to 4 hours and basin depths vary from 10 to 15 feet (3 to 4.5 meters).

440: 911: 535:, also called a clarifier or settling basin. It is a large tank with low water velocities, allowing floc to settle to the bottom. The sedimentation basin is best located close to the flocculation basin so the transit between the two processes does not permit settlement or floc break up. Sedimentation basins may be rectangular, where water flows from end to end, or circular where flow is from the centre outward. Sedimentation basin outflow is typically over a weir so only a thin top layer of water—that furthest from the sludge—exits. 1164:, and shadowing caused by the suspended solids. The main disadvantage to the use of UV radiation is that, like ozone treatment, it leaves no residual disinfectant in the water; therefore, it is sometimes necessary to add a residual disinfectant after the primary disinfection process. This is often done through the addition of chloramines, discussed above as a primary disinfectant. When used in this manner, chloramines provide an effective residual disinfectant with very few of the negative effects of chlorination. 1111:

disinfection, or ozonation, is an effective method to inactivate harmful protozoa that form cysts. It also works well against almost all other pathogens. Ozone is made by passing oxygen through ultraviolet light or a "cold" electrical discharge. To use ozone as a disinfectant, it must be created on-site and added to the water by bubble contact. Some of the advantages of ozone include the production of fewer dangerous by-products and the absence of taste and odour problems (in comparison to

583:(DAF) is often used. After coagulation and flocculation processes, water flows to DAF tanks where air diffusers on the tank bottom create fine bubbles that attach to the floc resulting in a floating mass of concentrated floc. The floating floc blanket is removed from the surface and clarified water is withdrawn from the bottom of the DAF tank. Water supplies that are particularly vulnerable to unicellular algae blooms and supplies with low turbidity and high colour often employ DAF. 3882: 425:) may be added to alkaline waters in some circumstances to lower the pH. Alkaline water (above pH 7.0) does not necessarily mean that lead or copper from the plumbing system will not be dissolved into the water. The ability of water to precipitate calcium carbonate to protect metal surfaces and reduce the likelihood of toxic metals being dissolved in water is a function of pH, mineral content, temperature, alkalinity and calcium concentration. 1959: 705: 1013:, releases chlorine on contact with water. Handling the solid, however, requires more routine human contact through opening bags and pouring than the use of gas cylinders or bleach, which are more easily automated. The generation of liquid sodium hypochlorite is inexpensive and also safer than the use of gas or solid chlorine. Chlorine levels up to 4 milligrams per litre (4 parts per million) are considered safe in drinking water. 1618: 1378:. This is the "fur" that builds up on kettle elements, etc., in hard water areas. With the exception of calcium, boiling does not remove solutes of higher boiling point than water and in fact increases their concentration (due to some water being lost as vapour). Boiling does not leave a residual disinfectant in the water. Therefore, water that is boiled and then stored for any length of time may acquire new pathogens. 549:, inclined flat plates or tubes can be added to traditional sedimentation basins to improve particle removal performance. Inclined plates and tubes drastically increase the surface area available for particles to be removed in concert with Hazen's original theory. The amount of ground surface area occupied by a sedimentation basin with inclined plates or tubes can be far smaller than a conventional sedimentation basin. 606: 2071: 1801: 4195: 1419:. The vapour contacts a cool surface where it condenses as a liquid. Because the solutes are not normally vaporised, they remain in the boiling solution. Even distillation does not completely purify water, because of contaminants with similar boiling points and droplets of unvapourised liquid carried with the steam. However, 99.9% pure water can be obtained by distillation. 1955:. Alexander Cruickshank Houston used chlorination of the water to stem the epidemic. His installation fed a concentrated solution of chloride of lime to the water being treated. The chlorination of the water supply helped stop the epidemic and as a precaution, the chlorination was continued until 1911 when a new water supply was instituted. 630: 515:

chemicals are added followed by flocculation basins (detention times range from 15 to 45 minutes) where low energy inputs turn large paddles or other gentle mixing devices to enhance the formation of floc. In fact, coagulation and flocculation processes are ongoing once the metal salt coagulants are added.

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a very fine capillary canal, and fitted with a tap or a screw cap. The tap is turned on, and the cylinder placed in the amount of water required. The chlorine bubbles out, and in ten to fifteen minutes the water is absolutely safe. This method would be of use on a large scale, as for service water carts.

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in a linen bag to treat water. For many decades, Lyster's method remained the standard for U.S. ground forces in the field and in camps, implemented in the form of the familiar Lyster Bag (also spelled Lister Bag). The bag was made of canvas and could hold 36 gallons of water. It was porous and held

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are excellent anti-bacterial material and can decompose toxic halo-organic compounds such as pesticides into non-toxic organic products. Filtered water must be used soon after it is filtered, as the low amount of remaining microbes may proliferate over time. In general, these home filters remove over

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showed that the efficiency of a sedimentation process was a function of the particle settling velocity, the flow through the tank and the surface area of tank. Sedimentation tanks are typically designed within a range of overflow rates of 0.5 to 1.0 gallons per minute per square foot (or 1250 to 2500

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It occurred to me that chlorine gas might be found satisfactory ... if suitable means could be found for using it.... The next important question was how to render the gas portable. This might be accomplished in two ways: By liquefying it, and storing it in lead-lined iron vessels, having a jet with

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companies in London, including minimum standards of water quality for the first time. The Act "made provision for securing the supply to the Metropolis of pure and wholesome water", and required that all water be "effectually filtered" from 31 December 1855. This was followed up with legislation for

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Many municipalities have moved from free chlorine to chloramine as a disinfection agent. However, chloramine appears to be a corrosive agent in some water systems. Chloramine can dissolve the "protective" film inside older service lines, leading to the leaching of lead into residential spigots. This

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A subcategory of sedimentation is the removal of particulates by entrapment in a layer of suspended floc as the water is forced upward. The major advantage of floc blanket clarifiers is that they occupy a smaller footprint than conventional sedimentation. The disadvantages are that particle removal

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The goals of the treatment are to remove unwanted constituents in the water and to make it safe to drink or fit for a specific purpose in industry or medical applications. Widely varied techniques are available to remove contaminants like fine solids, micro-organisms and some dissolved inorganic and

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Portable water purification devices and methods are available for disinfection and treatment in emergencies or in remote locations. Disinfection is the primary goal, since aesthetic considerations such as taste, odour, appearance, and trace chemical contamination do not affect the short-term safety

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has accepted ozone as being safe; and it is applied as an anti-microbiological agent for the treatment, storage, and processing of foods. However, although fewer by-products are formed by ozonation, it has been discovered that ozone reacts with bromide ions in water to produce concentrations of the

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Organic polymers were developed in the 1960s as aids to coagulants and, in some cases, as replacements for the inorganic metal salt coagulants. Synthetic organic polymers are high molecular weight compounds that carry negative, positive or neutral charges. When organic polymers are added to water

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in the UK. The formation of THMs and haloacetic acids may be minimised by the effective removal of as many organics from the water as possible prior to chlorine addition. Although chlorine is effective in killing bacteria, it has limited effectiveness against pathogenic protozoa that form cysts in

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may be used where there is sufficient land and space, as the water flows very slowly through the filters. These filters rely on biological treatment processes for their action rather than physical filtration. They are carefully constructed using graded layers of sand, with the coarsest sand, along

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above the sand. The top layer removes organic compounds, which contribute to taste and odour. The space between sand particles is larger than the smallest suspended particles, so simple filtration is not enough. Most particles pass through surface layers but are trapped in pore spaces or adhere to

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In the literature, there is much debate and confusion over the usage of the terms coagulation and flocculation: Where does coagulation end and flocculation begin? In water purification plants, there is usually a high energy, rapid mix unit process (detention time in seconds) whereby the coagulant

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cause several simultaneous chemical and physical interactions on and among the particles. Within seconds, negative charges on the particles are neutralised by inorganic coagulants. Also within seconds, metal hydroxide precipitates of the iron and aluminium ions begin to form. These precipitates

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disease each year. The WHO estimates that 94% of these diarrhoeal disease cases are preventable through modifications to the environment, including access to safe water. Simple techniques for treating water at home, such as chlorination, filters, and solar disinfection, and for storing it in safe

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uses microorganisms to remove waste products from a contaminated area. Since 1991 bioremediation has been a suggested tactic to remove impurities such as alkanes, perchlorates, and metals. Bioremediation has seen success because perchlorates are highly soluble, making them difficult to remove.

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Water conditioning: This is a method of reducing the effects of hard water. In water systems subject to heating hardness salts can be deposited as the decomposition of bicarbonate ions creates carbonate ions that precipitate out of solution. Water with high concentrations of hardness salts can be

732:, natural sediments in a riverbank are used to provide the first stage of contaminant filtration. While typically not clean enough to be used directly for drinking water, the water gained from the associated extraction wells is much less problematic than river water taken directly from the river. 1479:

to reduce the concentrations of targeted contaminants. ISCO is accomplished by injecting or otherwise introducing oxidizers into the contaminated medium (soil or groundwater) to destroy contaminants. It can be used to remediate a variety of organic compounds, including some that are resistant to

660:. This contaminated water can be disposed of, along with the sludge from the sedimentation basin, or it can be recycled by mixing with the raw water entering the plant although this is often considered poor practice since it re-introduces an elevated concentration of bacteria into the raw water. 791:

use polymer membranes with chemically formed microscopic pores that can be used to filter out dissolved substances avoiding the use of coagulants. The type of membrane media determines how much pressure is needed to drive the water through and what sizes of micro-organisms can be filtered out.

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is an unstable molecule which readily gives up one atom of oxygen providing a powerful oxidising agent which is toxic to most waterborne organisms. It is a very strong, broad spectrum disinfectant that is widely used in Europe and in a few municipalities in the United States and Canada. Ozone

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is formed on the floor of the tank which must be removed and treated. The amount of sludge generated is significant, often 3 to 5 per cent of the total volume of water to be treated. The cost of treating and disposing of the sludge can impact the operating cost of a water treatment plant. The

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allow only positive ions to migrate from the treated water toward the negative electrode and only negative ions toward the positive electrode. High purity deionised water is produced continuously, similar to ion-exchange treatment. Complete removal of ions from water is possible if the right

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Membrane filters are an effective form of tertiary treatment when it is desired to reuse the water for industry, for limited domestic purposes, or before discharging the water into a river that is used by towns further downstream. They are widely used in industry, particularly for beverage

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Pumping and containment – The majority of water must be pumped from its source or directed into pipes or holding tanks. To avoid adding contaminants to the water, this physical infrastructure must be made from appropriate materials and constructed so that accidental contamination does not

1832:, John Gibb, installed an experimental filter, selling his unwanted surplus to the public. This method was refined in the following two decades by engineers working for private water companies, and it culminated in the first treated public water supply in the world, installed by engineer 914:

Pumps used to add required amounts of chemicals to the clear water at a water purification plant before distribution. From left to right: sodium hypochlorite for disinfection, zinc orthophosphate as a corrosion inhibitor, sodium hydroxide for pH adjustment, and fluoride for tooth decay

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Carbon dioxide or other low molecular weight gas can be mixed with contaminated water at high pressure and low temperature to exothermically form gas hydrate crystals. Hydrate may be separated by centrifuge or sedimentation. Water can be released from the hydrate crystals by heating.

50:), but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications. The history of water purification includes a wide variety of methods. The methods used include physical processes such as 216:: Typically located in the headwaters of river systems, upland reservoirs are usually sited above any human habitation and may be surrounded by a protective zone to restrict the opportunities for contamination. Bacteria and pathogen levels are usually low, but some bacteria, 1083:

is becoming more common as a disinfectant. Although chloramine is not as strong an oxidant, it provides a longer-lasting residual than free chlorine because of its lower redox potential compared to free chlorine. It also does not readily form THMs or haloacetic acids

1445:. Contaminants are left on the other side of the membrane. Reverse osmosis is theoretically the most thorough method of large scale water purification available, although perfect semi-permeable membranes are difficult to create. Unless membranes are well-maintained, 1365:

of water is not required, since heat resistant microbes do not affect intestines. The traditional advice of boiling water for ten minutes is mainly for additional safety, since microbes start expiring at temperatures greater than 60 °C (140 °F). Though the

329:) – The first step in purifying surface water is to remove large debris such as sticks, leaves, rubbish and other large particles which may interfere with subsequent purification steps. Most deep groundwater does not need screening before other purification steps. 3375:

Reece, R.J. (1907). "Report on the Epidemic of Enteric Fever in the City of Lincoln, 1904-5." In Thirty-Fifth Annual Report of the Local Government Board, 1905-6: Supplement Containing the Report of the Medical Officer for 1905-6. London:Local Government

1131:. Bromide can be found in fresh water supplies in sufficient concentrations to produce (after ozonation) more than 10 parts per billion (ppb) of bromate—the maximum contaminant level established by the USEPA. Ozone disinfection is also energy intensive. 1065:, which is a by-product regulated to low allowable levels in the United States. Chlorine dioxide can be supplied as an aqueous solution and added to water to avoid gas handling problems; chlorine dioxide gas accumulations may spontaneously detonate. 2019:

up by ropes, purifying water with the help of calcium hypochlorite solution. Each bag had a faucet attached, which was used to flush water for testing, as well as dispensing for use. This became the basis for present day systems of municipal water

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is practised (a process in which river water is injected into an aquifer to store the water in times of plenty so that it is available in times of drought), the groundwater may require additional treatment depending on applicable state and federal

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is commonly used in municipal regions with organic contamination, taste or odors. Many household water filters and fish tanks use activated carbon filters to purify water. Household filters for drinking water sometimes contain silver as metallic

633: 637: 636: 632: 631: 1739:/L. At water hardness above 5 mmol/L, higher incidence of gallstones, kidney stones, urinary stones, arthrosis, and arthropathies have been observed. Additionally, desalination processes can increase the risk of bacterial contamination. 638: 1016:

All forms of chlorine are widely used, despite their respective drawbacks. One drawback is that chlorine from any source reacts with natural organic compounds in the water to form potentially harmful chemical by-products. These by-products,

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membrane. Evaporated water passes from the hot side through pores in the membrane forming a stream of cold pure water on the other side. The difference in vapour pressure between the hot and cold side helps to push water molecules through.

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Pre-chlorination – In many plants the incoming water was chlorinated to minimise the growth of fouling organisms on the pipe-work and tanks. Because of the potential adverse quality effects (see chlorine below), this has largely been

2176: 1115:). No residual ozone is left in the water. In the absence of a residual disinfectant in the water, chlorine or chloramine may be added throughout a distribution system to remove any potential pathogens in the distribution piping. 663:

Some water treatment plants employ pressure filters. These work on the same principle as rapid gravity filters, differing in that the filter medium is enclosed in a steel vessel and the water is forced through it under pressure.

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Aluminum hydroxides are formed within a fairly narrow pH range, typically: 5.5 to about 7.7. Iron (III) hydroxides can form over a larger pH range including pH levels lower than are effective for alum, typically: 5.0 to 8.5.

3679: 1936:) to water to render it "germ-free." Two other investigators confirmed Traube's findings and published their papers in 1895. Early attempts at implementing water chlorination at a water treatment plant were made in 1893 in 1328:

Other popular methods for purifying water, especially for local private supplies are listed below. In some countries some of these methods are used for large scale municipal supplies. Particularly important are distillation

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with some gravel, at the bottom and the finest sand at the top. Drains at the base convey treated water away for disinfection. Filtration depends on the development of a thin biological layer, called the zoogleal layer or

1009:, which is a relatively inexpensive solution used in household bleach that releases free chlorine when dissolved in water. Chlorine solutions can be generated on site by electrolyzing common salt solutions. A solid form, 626:

sand particles. Effective filtration extends into the depth of the filter. This property of the filter is key to its operation: if the top layer of sand were to block all the particles, the filter would quickly clog.

656:) to remove embedded or unwanted particles. Prior to this step, compressed air may be blown up through the bottom of the filter to break up the compacted filter media to aid the backwashing process; this is known as 1404:

90% of the chlorine in a glass of treated water. These filters must be periodically replaced otherwise the bacterial content of the water may actually increase due to the growth of bacteria within the filter unit.

1267:. Several other methods of industrial and residential water treatment are claimed (without general scientific acceptance) to include the use of magnetic and/or electrical fields reducing the effects of hard water. 499:. Amorphous metal hydroxides are known as "floc". Large, amorphous aluminium and iron (III) hydroxides adsorb and enmesh particles in suspension and facilitate the removal of particles by subsequent processes of 1871:

and statistical proof to illustrate the connection between the quality of the water source and cholera cases. His data convinced the local council to disable the water pump, which promptly ended the outbreak.

1531:) is a common disinfectant that can purify water. It is typically produced at chemical plants and transported to the contaminated water. An alternative approach employs a gold-palladium catalyst to synthesize 926:

which pass through the filters and to provide a residual dose of disinfectant to kill or inactivate potentially harmful micro-organisms in the storage and distribution systems. Possible pathogens include

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Distillation removes all minerals from water, and the membrane methods of reverse osmosis and nanofiltration remove most to all minerals. This results in demineralised water which is not considered ideal

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the mandatory inspection of water quality, including comprehensive chemical analyses, in 1858. This legislation set a worldwide precedent for similar state public health interventions across Europe. The

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One of the first steps in most conventional water purification processes is the addition of chemicals to assist in the removal of particles suspended in water. Particles can be inorganic such as

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can be added to raise the pH during water purification processes. Lime addition increases the calcium ion concentration, thus raising the water hardness. For highly acidic waters, forced draft

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are typically set by governments or by international standards. These standards usually include minimum and maximum concentrations of contaminants, depending on the intended use of the water.

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in London in 1829. This installation provided filtered water for every resident of the area, and the network design was widely copied throughout the United Kingdom in the ensuing decades.

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with increasing altitude, it is not enough to affect disinfection. In areas where the water is "hard" (that is, containing significant dissolved calcium salts), boiling decomposes the

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sedimentation basin may be equipped with mechanical cleaning devices that continually clean its bottom, or the basin can be periodically taken out of service and cleaned manually.

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The processes below are the ones commonly used in water purification plants. Some or most may not be used depending on the scale of the plant and quality of the raw (source) water.

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Fluoride Removal: Although fluoride is added to water in many areas, some areas of the world have excessive levels of natural fluoride in the source water. Excessive levels can be

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that rapidly kills many harmful micro-organisms. Because chlorine is a toxic gas, there is a danger of a release associated with its use. This problem is avoided by the use of

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Manufacturers of home water distillers claim the opposite—that minerals in water are the cause of many diseases, and that most beneficial minerals come from food, not water.

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and low land reservoirs: Low land surface waters will have a significant bacterial load and may also contain algae, suspended solids and a variety of dissolved constituents.

3711: 692: 634: 306:. The choice of method will depend on the quality of the water being treated, the cost of the treatment process and the quality standards expected of the processed water. 303: 1628: 1597: 3398:

Fuller, George W. (1909). "Description of the Process and Plant of the Jersey City Water Supply Company for the Sterilization of the Water of the Boonton Reservoir."

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The practice of water treatment soon became mainstream and common, and the virtues of the system were made starkly apparent after the investigations of the physician

1708:. The World Health Organization has investigated the health effects of demineralised water since 1980. Experiments in humans found that demineralised water increased 255:

which collect water from the atmosphere can be used especially in areas with significant dry seasons and in areas which experience fog even when there is little rain.

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with particulates, the high molecular weight compounds adsorb onto particle surfaces and through interparticle bridging coalesce with other particles to form floc.

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to observe for the first time small material particles that lay suspended in the water, laying the groundwork for the future understanding of waterborne pathogens.

2094: 2657: 1300:, United States of America. Radium can be removed by ion exchange, or by water conditioning. The back flush or sludge that is produced is, however, a low-level 1030: 1139: 1095:

to the water after adding chlorine. The chlorine and ammonia react to form chloramine. Water distribution systems disinfected with chloramines may experience

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Nair, Abhilash T.; Ahammed, M. Mansoor; Davra, Komal (1 August 2014). "Influence of operating parameters on the performance of a household slow sand filter".

1156:(UV) is very effective at inactivating cysts, in low turbidity water. UV light's disinfection effectiveness decreases as turbidity increases, a result of the 3456: 3941: 3915: 3574: 1061:

is a faster-acting disinfectant than elemental chlorine. It is relatively rarely used because in some circumstances it may create excessive amounts of

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for periods between a few days and many months to allow natural biological purification to take place. This is especially important if treatment is by

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is a new technology that can provide high quality drinking water by extracting water from the air by cooling the air and thus condensing water vapour.

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can have pH values that range from 7.5 to 8.4 (moderately alkaline). Fresh water can have widely ranging pH values depending on the geology of the

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and rock layers naturally filter the ground water to a high degree of clarity and often, it does not require additional treatment besides adding

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quality (i.e., pathogenic bacteria or the pathogenic protozoa are typically absent), but the water may be rich in dissolved solids, especially

1756: 971:. After the introduction of any chemical disinfecting agent, the water is usually held in temporary storage – often called a contact tank or 3613: 3531: 3498: 3276: 2429:

Neemann, Jeff; Hulsey, Robert; Rexing, David; Wert, Eric (2004). "Controlling Bromate Formation During Ozonation with Chlorine and Ammonia".

2375: 2251: 1399:. If water is held in the carbon block for longer periods, microorganisms can grow inside which results in fouling and contamination. Silver 2844:

John P Osegovic; John Ellington; Leslie Brazel; Brian Blake‐Collins; Miguel Mike DeJesus; Kathryn Sheps; Shelli Tatro; Michael Max (2009).

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Over the next few years, chlorine disinfection using chloride of lime were rapidly installed in drinking water systems around the world.

1896:. Automatic pressure filters, where the water is forced under pressure through the filtration system, were innovated in 1899 in England. 4230: 340:. Storage reservoirs also provide a buffer against short periods of drought or to allow water supply to be maintained during transitory 288: 4017: 2624: 1989:

The technique of purification of drinking water by use of compressed liquefied chlorine gas was developed by a British officer in the

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is accomplished both by filtering out harmful micro-organisms and by adding disinfectant chemicals. Water is disinfected to kill any

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rocks), the water may be capable of dissolving lead from any lead pipes that it is carried in. The addition of small quantities of

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filter are not sufficient for treating all possible contaminants that may be present in water from an unknown source. Even natural

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from ambient hydrogen and oxygen atoms at the use site. The latter was reported to be faster and 10 times more potent at killing

1493: 1251:. Fluoride is usually added after the disinfection process. In the U.S., fluoridation is usually accomplished by the addition of 597:

After separating most floc, the water is filtered as the final step to remove remaining suspended particles and unsettled floc.

130:, while expensive, are the only way to obtain the information necessary for deciding on the appropriate method of purification. 46:. The goal is to produce water that is fit for specific purposes. Most water is purified and disinfected for human consumption ( 4007: 3931: 3904: 3784: 3754: 1982:) at doses of 0.2 to 0.35 ppm. The treatment process was conceived by John L. Leal and the chlorination plant was designed by 1311:

or cause undesirable cosmetic effects such as staining of teeth. Methods of reducing fluoride levels is through treatment with

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can be an effective way to raise the pH, by stripping dissolved carbon dioxide from the water. Making the water alkaline helps

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slightly both assist in greatly reducing plumbo-solvency by creating insoluble lead salts on the inner surfaces of the pipes.

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The first continuous use of chlorine in the United States for disinfection took place in 1908 at Boonton Reservoir (on the

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can also be used as disinfectants. However, chlorine in water is over three times more effective as a disinfectant against

2244: 652: 402: 4185: 148:: The water emerging from some deep ground water may have fallen as rain many tens, hundreds, or thousands of years ago. 2067:

The global water purification market is worth 22 billion dollars. Home water filters and purifiers in India are common.

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that had helped spread the cholera outbreak. William Soper also used chlorinated lime to treat the sewage produced by

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processes work effectively and also helps to minimise the risk of lead being dissolved from lead pipes and from lead

279:: Freshwater bodies that are open to the atmosphere and are not designated as groundwater are termed surface waters. 4147: 4086: 3108:"Health risks from drinking demineralised water. Rolling revision of the WHO Guidelines for drinking-water quality" 2970:

Coates, John D.; Achenbach, Laurie A. (1 July 2004). "Microbial perchlorate reduction: rocket-fuelled metabolism".

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reduction: In areas with naturally acidic waters of low conductivity (i.e. surface rainfall in upland mountains of

439: 1776:. Although his experiment did not succeed, it marked the beginning of a new interest in the field. The fathers of 910: 4215: 4142: 4127: 3860: 3744: 3604:

Eaton, Andrew D.; Greenberg, Arnold E.; Rice, Eugene W.; Clesceri, Lenore S.; Franson, Mary Ann H., eds. (2005).

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Hatzinger, P. B.; Diebold, J.; Yates, C. A.; Cramer, R. J. (1 January 2006). Gu, Baohua; Coates, John D. (eds.).

2032: 1876: 2010:, gave the first practical demonstration of this in 1910. Shortly thereafter, Major William J. L. Lyster of the 1118:

Ozone has been used in drinking water plants since 1906 where the first industrial ozonation plant was built in

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was formed at the same time, water filtration was adopted throughout the country, and new water intakes on the

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efficiency can be highly variable depending on changes in influent water quality and influent water flow rate.

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They are reasonably strong and so can withstand pressure differences across them of typically 2–5 atmospheres.

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To clean the filter, water is passed quickly upward through the filter, opposite the normal direction (called

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Manual-control chlorinator for the liquefaction of chlorine for water purification, early 20th century. From

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Over 2 million people in 28 developing countries use Solar Disinfection for daily drinking water treatment.

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is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from

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had not yet been developed, Snow's observations led him to discount the prevailing theory. His 1855 essay

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with a high surface area. It adsorbs many compounds including many toxic compounds. Water passing through

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Leal, John L. (1909). "The Sterilization Plant of the Jersey City Water Supply Company at Boonton, N.J."

1349:(about 100 °C or 212 F at sea level), is the oldest and most effective way since it eliminates most 100:, viruses, and fungi as well as reduce the concentration of a range of dissolved and particulate matter. 4034: 4001: 3870: 2040: 1910: 1844: 1805: 3547: 3114: 413:

in pipe fittings. Sufficient alkalinity also reduces the corrosiveness of water to iron pipes. Acid (

4172: 4102: 4092: 4029: 3965: 3779: 3749: 3247: 2778: 2015: 1979: 1933: 1868: 1010: 434: 248: 205: 123: 119: 31: 3228: 2540:"Recommendations for using fluoride to prevent and control dental decay caries in the United States" 30:

This article is about treatment of natural water sources (mainly). For treatment of wastewater, see

4157: 4152: 4107: 4066: 3996: 3881: 3665: 2819: 2057: 2007: 2003: 1396: 1006: 878: 788: 740: 333: 110:

A visual inspection cannot determine if water is of appropriate quality. Simple procedures such as

3975: 3957: 3910: 3865: 3835: 2995: 2794: 2446: 2119: 1905: 1760:

Drawing of an apparatus for studying the chemical analysis of mineral waters in a book from 1799.

1240: 1112: 984: 799: 487: 89: 75: 3207: 1292:, a radioactive chemical element. Typical sources include many groundwater sources north of the 1099:, as ammonia is a nutrient for bacterial growth, with nitrates being generated as a by-product. 765:). However no filtration can remove substances that are actually dissolved in the water such as 3514: 2938: 1978:. Chlorination was achieved by controlled additions of dilute solutions of chloride of lime ( 4022: 3899: 3632: 3609: 3527: 3494: 3293: 3272: 3089: 2987: 2950: 2911: 2707: 2551: 2520: 2371: 2323:. Cincinnati, OH: United States Environmental Protection Agency (EPA). 1990. EPA/625/4-89/023. 2300: 2274: 2247: 2156: 1829: 1688: 1507: 1469: 1375: 1312: 1308: 1301: 1260: 1259:

treated with soda ash (sodium carbonate) which precipitates out the excess salts, through the

872: 868: 834: 614: 546: 523:

is a popular cationic (positively charged) organic polymer used in water purification plants.

479: 418: 414: 213: 63: 3266: 3040: 4117: 4071: 4038: 4012: 3986: 3936: 3920: 3774: 3769: 3739: 3649:

Overview and detailed information on US regulatory program and related drinking water topics

3438: 3079: 3071: 3060:"Changes in Blood Lead Levels Associated with Use of Chloramines in Water Treatment Systems" 2979: 2942: 2930: 2901: 2786: 2697: 2510: 2502: 2438: 2343: 2208: 1983: 1958: 1952: 1948: 1863:

conclusively demonstrated the role of the water supply in spreading the cholera epidemic in

1680: 1554: 1391: 1387: 1196: 1058: 998: 864: 712: 618: 394: 337: 200:

content of this water to make it acceptable for drinking, cooking, and laundry use. Primary

161: 115: 67: 2845: 2155:. Denver: AWWA Research Foundation and American Water Works Association. pp. 376–378. 164:, or may be extracted from boreholes or wells. Deep ground water is generally of very high 4137: 4112: 3980: 3970: 3683: 2571: 2321:"Technologies for Upgrading Existing or Designing New Drinking Water Treatment Facilities" 2320: 2129: 2124: 2114: 2099: 1893: 1592: 1438: 1422:

Direct contact membrane distillation (DCMD) passes heated seawater along the surface of a

1046: 1040: 1022: 961: 891: 807: 785: 755: 729: 704: 697: 622: 492: 386: 341: 270: 2890:"Thermodynamic targeting of microbial perchlorate reduction by selective electron donors" 2782: 902:. A water recovery of 99% is possible if the concentrate stream is fed to the RO inlet. 4061: 4043: 3814: 3794: 3759: 3084: 3059: 2587: 2464: 2442: 2415:

Neumann, H. (1981). "Bacteriological safety of hot tap water in developing countries."

2245:

https://www.accessengineeringlibrary.com/content/book/9780071630115?implicit-login=true

1971: 1732: 1705: 1488: 1293: 1270: 1074: 1018: 967: 899: 844: 532: 398: 374: 252: 47: 3646: 3442: 2515: 2491:"Comparison of Chlorine, Bromine, and Iodine as Disinfectants for Swimming Pool Water" 2490: 1579:, and over 10 times more effective than chlorine The catalytic reaction also produces 605: 4209: 3799: 3764: 2931: 2798: 2539: 2061: 1929: 1852: 1765: 1709: 1601: 1346: 1096: 945: 860: 762: 422: 325: 276: 104: 2999: 2450: 4199: 4162: 4081: 1880: 1785: 1769: 1412: 1400: 1330: 1026: 919: 795: 717: 708:

A profile of layers of gravel, sand and fine sand used in a slow sand filter plant.

592: 504: 496: 406: 266: 258: 201: 139: 71: 59: 3185: 2726: 2506: 2070: 1800: 17: 3457:"Disinfecting Water in a Lyster Bag – Communicable Diseases and Field Sanitation" 2365: 2294: 2150: 4097: 3309:

An Act to make better Provision respecting the Supply of Water to the Metropolis

3152: 2075: 1825: 1773: 1717: 1713: 1423: 1371: 1248: 1153: 539: 193: 157: 145: 85:

Water purification can reduce the concentration of particulate matter including

1944:, England was the first to have its entire water supply treated with chlorine. 1764:

The first experiments into water filtration were made in the 17th century. Sir

2863: 2790: 2048: 1789: 1777: 1692: 1264: 1161: 1080: 994: 972: 933: 848: 766: 520: 225: 51: 3323:

Public Water-Supplies: Requirements, Resources, and the Construction of Works

3058:

Miranda, M. L.; Kim, D.; Hull, A. P.; Paul, C. J.; Galeano, M. A. O. (2006).

2946: 2056:

containers could save a huge number of lives each year. Reducing deaths from

1608:) are often used in water purification plants to detect acute water pollution 188:

through which the water has flowed, other ions may also be present including

4194: 4167: 3890: 2052: 1941: 1736: 1724: 1720: 1354: 1316: 1278: 923: 882: 856: 826: 815: 472: 382: 370: 197: 181: 169: 3689: 3672:

Emergency Disinfection of Drinking Water – Camping, Hiking and Travel (CDC)

3093: 2991: 2915: 2906: 2889: 2740: 2711: 2555: 1951:

and a contaminated water supply led to a serious typhoid fever epidemic in

1828:

to purify the water supply dates to 1804, when the owner of a bleachery in

1179:(X-rays, gamma rays, and electron beams) has been used to sterilise water. 674:

Filters out virtually all particles larger than their specified pore sizes.

2524: 1855:

that stated that diseases were caused by noxious "bad airs". Although the

3575:"12% of urban India relies on bottled water, 1 in 4 homes has a purifier" 3427:"A Chemical Method of Sterilizing Water Without Affecting its Potability" 3015:"Researchers develop cheap, simple, on-demand water disinfection process" 2044: 1914: 1350: 1334: 1297: 1244: 1062: 1002: 990: 956: 951: 464: 390: 362: 262: 217: 189: 165: 153: 93: 2347: 1204:, and over six times more effective than an equivalent concentration of 700:) into the ground at the Water purification plant Káraný, Czech Republic 3991: 2983: 1937: 1922: 1813: 1728: 1426: 1274: 1201: 1187: 1128: 1092: 939: 928: 852: 838: 830: 811: 803: 770: 749: 557:

As particles settle to the bottom of a sedimentation basin, a layer of

460: 378: 185: 177: 173: 111: 3523: 3075: 2149:

McGuire, Michael J.; McLain, Jennifer Lara; Obolensky, Alexa (2002).

1889: 1416: 1358: 1289: 1205: 1191: 829:

ions. Ion-exchange resins are also used to remove toxic ions such as

822: 744: 558: 410: 366: 3426: 2764:"Nanomaterials and Water Purification: Opportunities and Challenges" 2564:"CDC Releases New Guidelines on Fluoride Use to Prevent Tooth Decay" 1475:(ISCO) is an advanced oxidation process. It is used for soil and/or 1143:

Cutaway model of UV disinfection unit used in water treatment plants

677:

They are quite thin and so liquids flow through them fairly rapidly.

3548:"Water Purifier Market Size, Share & Growth | Report till 2029" 2741:"Is it true that you can't make a decent cup of tea up a mountain?" 2702: 2685: 671:

Filters out much smaller particles than paper and sand filters can.

579:

When particles to be removed do not settle out of solution easily,

3619: 2069: 1957: 1799: 1755: 1596: 1499:

include field studies conducted in Maryland and the US Southwest.

1446: 1138: 1107: 909: 806:-packed columns to replace unwanted ions. The most common case is 703: 691: 628: 604: 456: 438: 287: 236: 221: 97: 43: 1679:

in the United States of America, became contaminated with excess

617:. Water moves vertically through sand which often has a layer of 1918: 1864: 1119: 483: 452: 448: 149: 3693: 2727:"OA Guide to Water Purification, The Backpacker's Field Manual" 2686:"Water Disinfection for International and Wilderness Travelers" 2074:

Control room and schematics of the water purification plant of

1993:, Vincent B. Nesfield, in 1903. According to his own account: 1611: 1441:

involves mechanical pressure applied to force water through a

818: 491:

combine into larger particles under natural processes such as

160:

as secondary disinfectants. Such water may emerge as springs,

3325:(1st ed.). New York: John Wiley & Sons. p. 493. 2296:

Integrated Design and Operation of Water Treatment Facilities

1627:

deal primarily with the United States and do not represent a

890:

conditions are met. The water is normally pre-treated with a

495:

and through induced mixing which is sometimes referred to as

3606:

Standard Methods For the Examination of Water and Wastewater

2618:"Water fluoridation: a manual for engineers and technicians" 3153:"Water Distillers – Water Distillation – Myths, Facts, etc" 2862:

Wilson, John T. Jr; Wilson, Barbara H. (15 December 1987),

1282: 1091:

It is possible to convert chlorine to chloramine by adding

358: 229: 2888:

Van Trump, James Ian; Coates, John D. (18 December 2008).

1947:

Permanent water chlorination began in 1905, when a faulty

989:

The most common disinfection method involves some form of

3113:. World Health Organization, Geneva. 2004. Archived from 3660: 1636: 743:

are widely used for filtering both drinking water and

224:

will be present. Where uplands are forested or peaty,

4183: 3629:

Introduction to Environmental Engineering and Science

2820:"Puretec Industrial Water | What is Reverse Osmosis?" 471:. Inorganic and organic particles contribute to the 3483:

Combating Waterborne Diseases at the Household Level

3265:

Gunn, S. William A. & Masellis, Michele (2007).

3129: 3127: 2865:

Biodegradation of halogenated aliphatic hydrocarbons

2051:

and hygiene, while 1.8 million people die from

1932:

formally proposed the addition of chloride of lime (

1255:, which decomposes in water, yielding fluoride ions. 531:

Waters exiting the flocculation basin may enter the

4053: 3956: 3889: 3727: 3608:(21 ed.). American Public Health Association. 3208:"The Use of the Microscope in Water Filter History" 2538:Centers for Disease Control and Prevention (2001). 2367:

Ion exchange materials: properties and applications

1687:can result in harmful exposure, including elevated 228:can colour the water. Many upland sources have low 196:. There may be a requirement to reduce the iron or 78:; and the use of electromagnetic radiation such as 3686:– U.S. National Primary Drinking Water Regulations 3668:– Consumer Guide to Drinking Water in the US (EPA) 3573: 1683:(lye) when its treatment equipment malfunctioned. 332:Storage – Water from rivers may also be stored in 304:environmental persistent pharmaceutical pollutants 2679: 2677: 2675: 2489:Koski TA, Stuart LS, Ortenzio LF (1 March 1966). 1449:and other life forms can colonise the membranes. 1288:Radium Removal: Some groundwater sources contain 3136:"Health risks from drinking demineralised water" 975:– to allow the disinfecting action to complete. 3677:Code of Federal Regulations, Title 40, Part 141 2431:Journal of the American Water Works Association 1995: 642:A demo of backwashing on the left filter column 3268:Concepts and Practice of Humanitarian Medicine 2846:"Hydrates for Gypsum Stack Water Purification" 2095:List of water supply and sanitation by country 2047:are attributed to unsafe water and inadequate 1735:(adding magnesium and calcium) of 2 to 4 1247:is added to water with the goal of preventing 781:Removal of ions and other dissolved substances 683:They can be cleaned (back flushed) and reused. 3705: 3041:"Mysterious Glitch Poisons Town Water Supply" 2623:. Centers for Disease Control. Archived from 1625:The examples and perspective in this article 1583:(ROS) that bind and degrade other compounds. 1031:United States Environmental Protection Agency 1029:in large quantities and are regulated by the 696:Slow "artificial" filtration (a variation of 478:The addition of inorganic coagulants such as 8: 3389:American Water Works Association. pp. 100–9. 2762:Savage, Nora; Mamadou S. Diallo (May 2005). 2265: 2263: 2261: 2259: 2043:; 88% of the 4 billion annual cases of 1374:ions, resulting in partial precipitation as 898:, and with gas transfer membranes to remove 3321:Turneaure, F.E. & H.L. Russell (1901). 2411: 2409: 2359: 2357: 821:replacing them with benign (soap friendly) 609:Cutaway view of a typical rapid sand filter 443:Station for complex water treatment SKO-10K 3712: 3698: 3690: 3627:Masters, Gilbert M.; Ela, Wendell (2008). 2595:Centers for Disease Control and Prevention 2568:Centers for Disease Control and Prevention 2336:Water Science and Technology: Water Supply 2288: 2286: 2269:Crittenden, John C., et al., eds. (2005). 1851:. Snow was sceptical of the then-dominant 1361:or impurities. For human health, complete 385:). If the water is acidic (lower than 7), 292:Typical drinking water treatment processes 3083: 2905: 2701: 2514: 2299:. John Wiley & Sons. pp. 74–75. 2235: 2233: 2231: 2229: 2152:Information Collection Rule Data Analysis 1663:Learn how and when to remove this message 381:and the influence of contaminant inputs ( 27:Process of removing impurities from water 3805:Environmentally healthy community design 2271:Water Treatment: Principles and Design. 2105:Organisms involved in water purification 1772:sea water by passing the flow through a 1415:involves boiling water to produce water 4190: 3572:Sharma, Harikishan (29 November 2019). 2141: 1861:On the Mode of Communication of Cholera 1386:Granular activated carbon is a form of 885:and a negative electrode. Ion-exchange 3666:"Water On Tap: What You Need To Know." 3223: 3221: 2293:Kawamura, Susumu (14 September 2000). 2090:History of water supply and sanitation 1752:History of water supply and sanitation 1593:Distilled water § Health concerns 2883: 2881: 881:: Water is passed between a positive 7: 3298:. John Libbey Eurotext. p. 290. 2243:. 6th Edition. New York:McGraw-Hill. 1200:than an equivalent concentration of 613:The most common type of filter is a 3248:"History of the Chelsea Waterworks" 1675:In April 2007, the water supply of 1324:Other water purification techniques 3942:waste-water treatment technologies 2650:"Magnetic Water Treatment Devices" 2443:10.1002/j.1551-8833.2004.tb10542.x 1974:), which served as the supply for 1940:, Germany and in 1897 the city of 1913:was the first to successfully use 1849:1854 Broad Street cholera outbreak 1149:Ultraviolet germicidal irradiation 25: 3927:agricultural wastewater treatment 3647:"Ground Water and Drinking Water" 3338:Journal of the Sanitary Institute 3336:"Typhoid Epidemic at Maidstone". 3064:Environmental Health Perspectives 1917:to disinfect the water supply in 1906:Water chlorination § History 1886:Metropolitan Commission of Sewers 1879:introduced the regulation of the 1124:U.S. Food and Drug Administration 4193: 3880: 3661:American Water Works Association 3522:. World Health Organization and 3516:Water for Life: Making it Happen 3039:Poulsen, Kevin (26 April 2007). 2273:2nd Edition. Hoboken, NJ:Wiley. 2213:American Water Works Association 2006:, Professor of Chemistry at the 1616: 4008:List of energy storage projects 3932:industrial wastewater treatment 3785:Environmental impact assessment 3755:Environmental impact assessment 3618:. Also available on CD-ROM and 3013:Micu, Alexandre (2 July 2021). 2570:. 9 August 2007. Archived from 2239:Edzwald, James K., ed. (2011). 62:; biological processes such as 3631:. Hoboken, NJ: Prentice Hall. 3413:Clean Water and How to Get It. 3356:"A miracle for public health?" 2064:goal in developing countries. 2041:improved drinking water supply 1928:In a paper published in 1894, 1357:disease, but it cannot remove 1208:. Iodine is commonly used for 871:out of solution utilising the 486:) or iron (III) salts such as 344:incidents in the source river. 1: 3443:10.1016/s0033-3506(02)80142-1 2507:10.1128/AEM.14.2.276-279.1966 2364:Zagorodni, Andrei A. (2007). 1212:, and bromine is common as a 1054:Chlorine dioxide disinfection 70:; chemical processes such as 3230:Filtration of water supplies 3178:"Minerals in Drinking Water" 2392:"Disinfection with Chlorine" 2177:"Aeration and gas stripping" 1824:The first documented use of 1235:Additional treatment options 1183:Bromination and iodinisation 859:ions) is treated with lime ( 429:Coagulation and flocculation 243:Atmospheric water generation 204:may also be required. Where 3790:Environmental impact design 3552:fortunebusinessinsights.com 3295:L'histoire des vaccinations 3236:, World Health Organization 2972:Nature Reviews Microbiology 2241:Water Quality and Treatment 2110:Portable water purification 1639:, discuss the issue on the 1226:Portable water purification 1220:Portable water purification 1210:portable water purification 1035:Drinking Water Inspectorate 798:: Ion-exchange systems use 103:The standards for drinking 4247: 4231:Industrial water treatment 4148:High-performance buildings 3311:, (15 & 16 Vict. C.84) 2851:. AIChE Annual Convention. 2469:Center for Disease Control 1903: 1838:Chelsea Waterworks Company 1788:, used the newly invented 1749: 1590: 1223: 1214:swimming pool disinfectant 1146: 1072: 982: 590: 553:Sludge storage and removal 432: 137: 114:or the use of a household 68:biologically active carbon 29: 4143:Heat recovery ventilation 4128:Environmental remediation 3878: 3745:Climate smart agriculture 3491:World Health Organization 2791:10.1007/s11051-005-7523-5 2039:people lack access to an 2033:World Health Organization 993:or its compounds such as 894:unit to remove non-ionic 810:consisting of removal of 232:which require adjustment. 4133:Glass in green buildings 4077:sustainable architecture 3721:Environmental technology 3425:Nesfield, V. B. (1902). 3271:. Springer. p. 87. 3212:History of Water Filters 2947:10.1007/0-387-31113-0_14 2937:. Springer US. pp. 2597:(Report). September 1993 1587:Safety and controversies 1492:Example applications of 1135:Ultraviolet disinfection 128:microbiological analysis 3682:8 February 2009 at the 3415:New York:Wiley. p. 102. 2684:Backer, Howard (2002). 2012:Army Medical Department 1976:Jersey City, New Jersey 1892:were established above 1818:London epidemic of 1854 1782:Antonie van Leeuwenhoek 1712:and the elimination of 1581:reactive oxygen species 1477:groundwater remediation 1443:semi-permeable membrane 1368:boiling point decreases 1337:) and reverse osmosis. 1281:ion and increasing the 1086:disinfection byproducts 1001:. Chlorine is a strong 931:, bacteria, including 845:Precipitative softening 761:preparation (including 581:dissolved air flotation 575:Dissolved air flotation 566:Floc blanket clarifiers 4123:Environmental movement 3820:Sustainability science 3810:Public interest design 3735:Appropriate technology 3411:Hazen, Allen. (1916). 2907:10.1038/ismej.2008.119 2079: 2000: 1991:Indian Medical Service 1967: 1857:germ theory of disease 1821: 1761: 1677:Spencer, Massachusetts 1609: 1345:Bringing water to its 1253:hexafluorosilicic acid 1144: 916: 709: 701: 643: 610: 469:natural organic matter 444: 302:organic materials, or 293: 4002:hydrogen technologies 3916:Solid waste treatment 3292:Bazin, Hervé (2008). 3157:Naturalsolutions1.com 2725:Curtis, Rick (1998). 2073: 1984:George Warren Fuller. 1966:by Joseph Race, 1918. 1964:Chlorination of Water 1961: 1803: 1759: 1750:Further information: 1600: 1591:Further information: 1495:Dechloromonas agitata 1142: 1127:suspected carcinogen 979:Chlorine disinfection 913: 707: 695: 641: 608: 475:and colour of water. 442: 291: 138:Further information: 4173:Water heat recycling 4103:Efficient energy use 4093:Conservation biology 4030:Sustainable lighting 3966:Efficient energy use 3780:Environmental Design 3750:Environmental design 3461:armymedical.tpub.com 3344:: 388. October 1897. 3188:on 30 September 2010 2654:Penn State Extension 2495:Applied Microbiology 2465:"Solar Disinfection" 2031:According to a 2007 2016:calcium hypochlorite 1980:calcium hypochlorite 1934:calcium hypochlorite 1877:Metropolis Water Act 1869:dot distribution map 1867:, with the use of a 1645:create a new article 1637:improve this article 1480:natural degradation 1011:calcium hypochlorite 896:organic contaminants 435:Particle aggregation 361:close to 7 (neither 249:Rainwater harvesting 206:groundwater recharge 32:wastewater treatment 4158:Nature conservation 4153:Land rehabilitation 4108:Energy conservation 3997:carbon-neutral fuel 3905:dispersion modeling 3134:Kozisek F. (2004). 3120:on 7 February 2006. 2783:2005JNR.....7..331S 2771:J. Nanoparticle Res 2588:Fluoridation census 2348:10.2166/ws.2014.021 2058:waterborne diseases 2014:used a solution of 2008:Army Medical School 2004:Carl Rogers Darnall 1699:Demineralized water 1606:Oncorhynchus mykiss 1397:silver nanoparticle 1231:of drinking water. 1007:sodium hypochlorite 879:Electrodeionization 863:) and/or soda-ash ( 736:Membrane filtration 533:sedimentation basin 455:or organic such as 334:bankside reservoirs 184:. Depending on the 3976:Energy development 3958:Sustainable energy 3947:water purification 3911:Industrial ecology 3580:The Indian Express 3182:Aquatechnology.net 2984:10.1038/nrmicro926 2616:Reeves TG (1986). 2120:Water conservation 2080: 2035:(WHO) report, 1.1 1968: 1925:patients in 1879. 1900:Water chlorination 1822: 1762: 1691:. Lead is a known 1610: 1473:chemical oxidation 1241:Water fluoridation 1177:ionizing radiation 1171:Ionizing radiation 1145: 1103:Ozone disinfection 985:Water chlorination 917: 800:ion-exchange resin 710: 702: 644: 611: 601:Rapid sand filters 547:Lamella clarifiers 488:iron(III) chloride 445: 294: 40:Water purification 18:Water disinfection 4181: 4180: 4018:commercialization 3615:978-0-87553-047-5 3533:978-92-4-156293-5 3500:978-92-4-159522-3 3402:AWWA. pp. 110–34. 3278:978-0-387-72264-1 2660:on 15 August 2017 2630:on 7 October 2008 2377:978-0-08-044552-6 2252:978-0-07-163011-5 2209:"Water Knowledge" 2045:diarrheal disease 1830:Paisley, Scotland 1716:, with decreased 1689:blood lead levels 1673: 1672: 1665: 1647:, as appropriate. 1508:Hydrogen peroxide 1503:Hydrogen peroxide 1376:calcium carbonate 1313:activated alumina 1302:radioactive waste 1261:common-ion effect 1154:Ultraviolet light 1025:(HAAs), are both 873:common-ion effect 869:calcium carbonate 867:) to precipitate 847:: Water rich in 841:and many others. 713:Slow sand filters 688:Slow sand filters 639: 615:rapid sand filter 480:aluminium sulfate 419:hydrochloric acid 357:Pure water has a 338:slow sand filters 212:Upland lakes and 80:ultraviolet light 64:slow sand filters 16:(Redirected from 4238: 4216:Water technology 4198: 4197: 4189: 4118:Energy recycling 4039:electric vehicle 4013:Renewable energy 3987:alternative fuel 3937:sewage treatment 3921:Waste management 3884: 3775:Energy recycling 3770:Electric vehicle 3740:Clean technology 3714: 3707: 3700: 3691: 3642: 3623: 3622:by subscription. 3591: 3590: 3588: 3586: 3577: 3569: 3563: 3562: 3560: 3558: 3544: 3538: 3537: 3521: 3511: 3505: 3504: 3493:. 2007. Part 1. 3488: 3478: 3472: 3471: 3469: 3467: 3453: 3447: 3446: 3422: 3416: 3409: 3403: 3396: 3390: 3383: 3377: 3373: 3367: 3366: 3364: 3362: 3352: 3346: 3345: 3333: 3327: 3326: 3318: 3312: 3306: 3300: 3299: 3289: 3283: 3282: 3262: 3256: 3255: 3244: 3238: 3237: 3235: 3225: 3216: 3215: 3204: 3198: 3197: 3195: 3193: 3184:. Archived from 3174: 3168: 3167: 3165: 3163: 3149: 3143: 3142: 3140: 3131: 3122: 3121: 3119: 3112: 3104: 3098: 3097: 3087: 3076:10.1289/ehp.9432 3055: 3049: 3048: 3036: 3030: 3029: 3027: 3025: 3010: 3004: 3003: 2967: 2961: 2960: 2936: 2926: 2920: 2919: 2909: 2894:The ISME Journal 2885: 2876: 2875: 2874: 2872: 2859: 2853: 2852: 2850: 2841: 2835: 2834: 2832: 2830: 2824:puretecwater.com 2816: 2810: 2809: 2807: 2805: 2777:(4–5): 331–342. 2768: 2759: 2753: 2752: 2750: 2748: 2737: 2731: 2730: 2722: 2716: 2715: 2705: 2681: 2670: 2669: 2667: 2665: 2656:. Archived from 2646: 2640: 2639: 2637: 2635: 2629: 2622: 2613: 2607: 2606: 2604: 2602: 2592: 2584: 2578: 2575: 2574:on 8 March 2008. 2559: 2535: 2529: 2528: 2518: 2486: 2480: 2479: 2477: 2475: 2461: 2455: 2454: 2426: 2420: 2413: 2404: 2403: 2401: 2399: 2388: 2382: 2381: 2361: 2352: 2351: 2331: 2325: 2324: 2317: 2311: 2310: 2290: 2281: 2267: 2254: 2237: 2224: 2223: 2221: 2219: 2205: 2199: 2198: 2196: 2194: 2188: 2182:. Archived from 2181: 2173: 2167: 2166: 2146: 2002:U.S. Army Major 1953:Lincoln, England 1949:slow sand filter 1804:Original map by 1681:sodium hydroxide 1668: 1661: 1657: 1654: 1648: 1620: 1619: 1612: 1578: 1577: 1576: 1568: 1567: 1558:than commercial 1555:Escherichia coli 1551: 1550: 1549: 1541: 1540: 1530: 1529: 1528: 1520: 1519: 1392:activated carbon 1388:activated carbon 1243:: in many areas 1197:Escherichia coli 1059:Chlorine dioxide 1023:haloacetic acids 999:chlorine dioxide 865:sodium carbonate 741:Membrane filters 640: 619:activated carbon 395:sodium hydroxide 162:artesian springs 134:Sources of water 116:activated carbon 21: 4246: 4245: 4241: 4240: 4239: 4237: 4236: 4235: 4226:Water treatment 4221:Water pollution 4206: 4205: 4204: 4192: 4184: 4182: 4177: 4138:Green computing 4113:Energy recovery 4049: 3981:Energy recovery 3971:Electrification 3952: 3898:Air pollution ( 3885: 3876: 3723: 3718: 3684:Wayback Machine 3657: 3652: 3639: 3626: 3616: 3603: 3599: 3597:Further reading 3594: 3584: 3582: 3571: 3570: 3566: 3556: 3554: 3546: 3545: 3541: 3534: 3519: 3513: 3512: 3508: 3501: 3486: 3480: 3479: 3475: 3465: 3463: 3455: 3454: 3450: 3424: 3423: 3419: 3410: 3406: 3397: 3393: 3384: 3380: 3374: 3370: 3360: 3358: 3354: 3353: 3349: 3335: 3334: 3330: 3320: 3319: 3315: 3307: 3303: 3291: 3290: 3286: 3279: 3264: 3263: 3259: 3246: 3245: 3241: 3233: 3227: 3226: 3219: 3206: 3205: 3201: 3191: 3189: 3176: 3175: 3171: 3161: 3159: 3151: 3150: 3146: 3138: 3133: 3132: 3125: 3117: 3110: 3106: 3105: 3101: 3057: 3056: 3052: 3038: 3037: 3033: 3023: 3021: 3012: 3011: 3007: 2969: 2968: 2964: 2957: 2928: 2927: 2923: 2887: 2886: 2879: 2870: 2868: 2861: 2860: 2856: 2848: 2843: 2842: 2838: 2828: 2826: 2818: 2817: 2813: 2803: 2801: 2766: 2761: 2760: 2756: 2746: 2744: 2739: 2738: 2734: 2729:. Random House. 2724: 2723: 2719: 2690:Clin Infect Dis 2683: 2682: 2673: 2663: 2661: 2648: 2647: 2643: 2633: 2631: 2627: 2620: 2615: 2614: 2610: 2600: 2598: 2590: 2586: 2585: 2581: 2562: 2550:(RR-14): 1–42. 2544:MMWR Recomm Rep 2537: 2536: 2532: 2488: 2487: 2483: 2473: 2471: 2463: 2462: 2458: 2428: 2427: 2423: 2419:Rep.84:812–814. 2414: 2407: 2397: 2395: 2390: 2389: 2385: 2378: 2363: 2362: 2355: 2333: 2332: 2328: 2319: 2318: 2314: 2307: 2292: 2291: 2284: 2268: 2257: 2238: 2227: 2217: 2215: 2207: 2206: 2202: 2192: 2190: 2189:on 12 July 2014 2186: 2179: 2175: 2174: 2170: 2163: 2148: 2147: 2143: 2139: 2134: 2130:Water treatment 2125:Water recycling 2115:Water softening 2100:Microfiltration 2085: 2029: 1908: 1902: 1894:Teddington Lock 1798: 1754: 1748: 1723:concentration. 1701: 1669: 1658: 1652: 1649: 1634: 1621: 1617: 1595: 1589: 1575: 1572: 1571: 1570: 1566: 1563: 1562: 1561: 1559: 1548: 1545: 1544: 1543: 1539: 1536: 1535: 1534: 1532: 1527: 1524: 1523: 1522: 1518: 1515: 1514: 1513: 1511: 1505: 1486: 1467: 1455: 1453:Crystallization 1439:Reverse osmosis 1436: 1434:Reverse osmosis 1410: 1384: 1359:chemical toxins 1343: 1326: 1237: 1228: 1222: 1185: 1173: 1151: 1137: 1105: 1077: 1071: 1056: 1047:Cryptosporidium 1041:Giardia lamblia 1019:trihalomethanes 987: 981: 962:Giardia lamblia 908: 892:reverse osmosis 808:water softening 786:Ultrafiltration 783: 756:Cryptosporidium 738: 730:bank filtration 726: 724:Bank filtration 698:bank filtration 690: 629: 623:anthracite coal 603: 595: 589: 577: 568: 555: 529: 493:Brownian motion 437: 431: 355: 315: 299: 286: 271:reverse osmosis 166:bacteriological 142: 136: 35: 28: 23: 22: 15: 12: 11: 5: 4244: 4242: 4234: 4233: 4228: 4223: 4218: 4208: 4207: 4203: 4202: 4179: 4178: 4176: 4175: 4170: 4165: 4160: 4155: 4150: 4145: 4140: 4135: 4130: 4125: 4120: 4115: 4110: 4105: 4100: 4095: 4090: 4084: 4079: 4074: 4069: 4064: 4057: 4055: 4051: 4050: 4048: 4047: 4044:hybrid vehicle 4041: 4035:Transportation 4032: 4027: 4026: 4025: 4020: 4010: 4005: 3999: 3994: 3989: 3983: 3978: 3973: 3968: 3962: 3960: 3954: 3953: 3951: 3950: 3944: 3939: 3934: 3929: 3923: 3918: 3913: 3908: 3902: 3895: 3893: 3887: 3886: 3879: 3877: 3875: 3874: 3868: 3863: 3858: 3853: 3848: 3843: 3838: 3833: 3828: 3822: 3817: 3815:Sustainability 3812: 3807: 3802: 3797: 3795:Green building 3792: 3787: 3782: 3777: 3772: 3767: 3762: 3760:Eco-innovation 3757: 3752: 3747: 3742: 3737: 3731: 3729: 3725: 3724: 3719: 3717: 3716: 3709: 3702: 3694: 3688: 3687: 3674: 3669: 3663: 3656: 3655:External links 3653: 3651: 3650: 3643: 3637: 3624: 3614: 3600: 3598: 3595: 3593: 3592: 3564: 3539: 3532: 3506: 3499: 3473: 3448: 3417: 3404: 3391: 3378: 3368: 3347: 3328: 3313: 3301: 3284: 3277: 3257: 3239: 3217: 3199: 3169: 3144: 3123: 3099: 3070:(2): 221–225. 3050: 3031: 3005: 2978:(7): 569–580. 2962: 2955: 2921: 2900:(4): 466–476. 2877: 2854: 2836: 2811: 2754: 2732: 2717: 2703:10.1086/324747 2696:(3): 355–364. 2671: 2641: 2608: 2579: 2577: 2576: 2530: 2501:(2): 276–279. 2481: 2456: 2421: 2405: 2383: 2376: 2353: 2342:(4): 643–649. 2326: 2312: 2305: 2282: 2255: 2225: 2200: 2168: 2161: 2140: 2138: 2135: 2133: 2132: 2127: 2122: 2117: 2112: 2107: 2102: 2097: 2092: 2086: 2084: 2081: 2028: 2025: 1972:Rockaway River 1901: 1898: 1797: 1794: 1747: 1744: 1733:water hardness 1706:drinking water 1700: 1697: 1671: 1670: 1631:of the subject 1629:worldwide view 1624: 1622: 1615: 1588: 1585: 1573: 1564: 1546: 1537: 1525: 1516: 1504: 1501: 1489:Bioremediation 1485: 1484:Bioremediation 1482: 1466: 1460: 1454: 1451: 1435: 1432: 1409: 1406: 1383: 1380: 1342: 1339: 1325: 1322: 1321: 1320: 1305: 1294:Illinois River 1286: 1271:Plumbosolvency 1268: 1256: 1236: 1233: 1224:Main article: 1221: 1218: 1184: 1181: 1172: 1169: 1147:Main article: 1136: 1133: 1122:, France. The 1104: 1101: 1075:Chloramination 1073:Main article: 1070: 1069:Chloramination 1067: 1055: 1052: 1038:water such as 1033:(EPA) and the 983:Main article: 980: 977: 968:cryptosporidia 907: 904: 900:carbon dioxide 782: 779: 737: 734: 725: 722: 689: 686: 685: 684: 681: 678: 675: 672: 602: 599: 588: 585: 576: 573: 567: 564: 554: 551: 528: 525: 430: 427: 375:drainage basin 354: 351: 350: 349: 345: 330: 320: 314: 311: 298: 295: 285: 282: 281: 280: 274: 256: 253:fog collection 246: 240: 233: 210: 135: 132: 48:drinking water 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 4243: 4232: 4229: 4227: 4224: 4222: 4219: 4217: 4214: 4213: 4211: 4201: 4196: 4191: 4187: 4174: 4171: 4169: 4166: 4164: 4161: 4159: 4156: 4154: 4151: 4149: 4146: 4144: 4141: 4139: 4136: 4134: 4131: 4129: 4126: 4124: 4121: 4119: 4116: 4114: 4111: 4109: 4106: 4104: 4101: 4099: 4096: 4094: 4091: 4088: 4087:New Classical 4085: 4083: 4080: 4078: 4075: 4073: 4070: 4068: 4065: 4063: 4059: 4058: 4056: 4052: 4045: 4042: 4040: 4036: 4033: 4031: 4028: 4024: 4021: 4019: 4016: 4015: 4014: 4011: 4009: 4006: 4003: 4000: 3998: 3995: 3993: 3990: 3988: 3984: 3982: 3979: 3977: 3974: 3972: 3969: 3967: 3964: 3963: 3961: 3959: 3955: 3948: 3945: 3943: 3940: 3938: 3935: 3933: 3930: 3928: 3924: 3922: 3919: 3917: 3914: 3912: 3909: 3906: 3903: 3901: 3897: 3896: 3894: 3892: 3888: 3883: 3872: 3869: 3867: 3864: 3862: 3861:refurbishment 3859: 3857: 3854: 3852: 3849: 3847: 3844: 3842: 3839: 3837: 3834: 3832: 3829: 3827: 3824:Sustainable ( 3823: 3821: 3818: 3816: 3813: 3811: 3808: 3806: 3803: 3801: 3800:Green vehicle 3798: 3796: 3793: 3791: 3788: 3786: 3783: 3781: 3778: 3776: 3773: 3771: 3768: 3766: 3765:Ecotechnology 3763: 3761: 3758: 3756: 3753: 3751: 3748: 3746: 3743: 3741: 3738: 3736: 3733: 3732: 3730: 3726: 3722: 3715: 3710: 3708: 3703: 3701: 3696: 3695: 3692: 3685: 3681: 3678: 3675: 3673: 3670: 3667: 3664: 3662: 3659: 3658: 3654: 3648: 3644: 3640: 3638:9780131481930 3634: 3630: 3625: 3621: 3617: 3611: 3607: 3602: 3601: 3596: 3581: 3576: 3568: 3565: 3553: 3549: 3543: 3540: 3535: 3529: 3525: 3518: 3517: 3510: 3507: 3502: 3496: 3492: 3485: 3484: 3477: 3474: 3462: 3458: 3452: 3449: 3444: 3440: 3436: 3432: 3431:Public Health 3428: 3421: 3418: 3414: 3408: 3405: 3401: 3395: 3392: 3388: 3382: 3379: 3372: 3369: 3357: 3351: 3348: 3343: 3339: 3332: 3329: 3324: 3317: 3314: 3310: 3305: 3302: 3297: 3296: 3288: 3285: 3280: 3274: 3270: 3269: 3261: 3258: 3253: 3249: 3243: 3240: 3232: 3231: 3224: 3222: 3218: 3213: 3209: 3203: 3200: 3187: 3183: 3179: 3173: 3170: 3158: 3154: 3148: 3145: 3137: 3130: 3128: 3124: 3116: 3109: 3103: 3100: 3095: 3091: 3086: 3081: 3077: 3073: 3069: 3065: 3061: 3054: 3051: 3046: 3042: 3035: 3032: 3020: 3016: 3009: 3006: 3001: 2997: 2993: 2989: 2985: 2981: 2977: 2973: 2966: 2963: 2958: 2956:9780387311142 2952: 2948: 2944: 2940: 2935: 2934: 2925: 2922: 2917: 2913: 2908: 2903: 2899: 2895: 2891: 2884: 2882: 2878: 2867: 2866: 2858: 2855: 2847: 2840: 2837: 2825: 2821: 2815: 2812: 2800: 2796: 2792: 2788: 2784: 2780: 2776: 2772: 2765: 2758: 2755: 2743:. physics.org 2742: 2736: 2733: 2728: 2721: 2718: 2713: 2709: 2704: 2699: 2695: 2691: 2687: 2680: 2678: 2676: 2672: 2659: 2655: 2651: 2645: 2642: 2626: 2619: 2612: 2609: 2596: 2589: 2583: 2580: 2573: 2569: 2565: 2561: 2560: 2557: 2553: 2549: 2545: 2541: 2534: 2531: 2526: 2522: 2517: 2512: 2508: 2504: 2500: 2496: 2492: 2485: 2482: 2470: 2466: 2460: 2457: 2452: 2448: 2444: 2440: 2436: 2432: 2425: 2422: 2418: 2417:Public Health 2412: 2410: 2406: 2393: 2387: 2384: 2379: 2373: 2369: 2368: 2360: 2358: 2354: 2349: 2345: 2341: 2337: 2330: 2327: 2322: 2316: 2313: 2308: 2306:9780471350934 2302: 2298: 2297: 2289: 2287: 2283: 2280: 2279:0-471-11018-3 2276: 2272: 2266: 2264: 2262: 2260: 2256: 2253: 2249: 2246: 2242: 2236: 2234: 2232: 2230: 2226: 2214: 2210: 2204: 2201: 2185: 2178: 2172: 2169: 2164: 2162:9781583212738 2158: 2154: 2153: 2145: 2142: 2136: 2131: 2128: 2126: 2123: 2121: 2118: 2116: 2113: 2111: 2108: 2106: 2103: 2101: 2098: 2096: 2093: 2091: 2088: 2087: 2082: 2078:, Switzerland 2077: 2072: 2068: 2065: 2063: 2062:public health 2059: 2054: 2050: 2046: 2042: 2038: 2034: 2026: 2024: 2022: 2017: 2013: 2009: 2005: 1999: 1994: 1992: 1987: 1985: 1981: 1977: 1973: 1965: 1960: 1956: 1954: 1950: 1945: 1943: 1939: 1935: 1931: 1930:Moritz Traube 1926: 1924: 1920: 1916: 1912: 1907: 1899: 1897: 1895: 1891: 1887: 1882: 1878: 1873: 1870: 1866: 1862: 1858: 1854: 1853:miasma theory 1850: 1846: 1841: 1839: 1835: 1834:James Simpson 1831: 1827: 1819: 1816:cases in the 1815: 1811: 1807: 1802: 1795: 1793: 1791: 1787: 1783: 1779: 1775: 1771: 1768:attempted to 1767: 1766:Francis Bacon 1758: 1753: 1745: 1743: 1740: 1738: 1734: 1730: 1726: 1722: 1719: 1715: 1711: 1707: 1698: 1696: 1694: 1690: 1684: 1682: 1678: 1667: 1664: 1656: 1646: 1642: 1638: 1632: 1630: 1623: 1614: 1613: 1607: 1603: 1602:Rainbow trout 1599: 1594: 1586: 1584: 1582: 1557: 1556: 1509: 1502: 1500: 1498: 1496: 1490: 1483: 1481: 1478: 1474: 1472: 1464: 1461: 1459: 1452: 1450: 1448: 1444: 1440: 1433: 1431: 1428: 1425: 1420: 1418: 1414: 1407: 1405: 1402: 1401:nanoparticles 1398: 1393: 1389: 1381: 1379: 1377: 1373: 1369: 1364: 1363:sterilisation 1360: 1356: 1352: 1348: 1347:boiling point 1340: 1338: 1336: 1332: 1323: 1319:filter media. 1318: 1314: 1310: 1306: 1303: 1299: 1295: 1291: 1287: 1284: 1280: 1276: 1272: 1269: 1266: 1262: 1257: 1254: 1250: 1246: 1242: 1239: 1238: 1234: 1232: 1227: 1219: 1217: 1215: 1211: 1207: 1203: 1199: 1198: 1193: 1189: 1182: 1180: 1178: 1170: 1168: 1165: 1163: 1159: 1155: 1150: 1141: 1134: 1132: 1130: 1125: 1121: 1116: 1114: 1109: 1102: 1100: 1098: 1097:nitrification 1094: 1089: 1087: 1082: 1076: 1068: 1066: 1064: 1060: 1053: 1051: 1049: 1048: 1043: 1042: 1036: 1032: 1028: 1024: 1020: 1014: 1012: 1008: 1004: 1000: 996: 992: 986: 978: 976: 974: 970: 969: 964: 963: 958: 954: 953: 948: 947: 946:Campylobacter 942: 941: 936: 935: 930: 925: 921: 912: 905: 903: 901: 897: 893: 888: 884: 880: 876: 874: 870: 866: 862: 861:calcium oxide 858: 854: 850: 846: 842: 840: 836: 832: 828: 824: 820: 817: 813: 809: 805: 801: 797: 793: 790: 787: 780: 778: 776: 772: 768: 764: 763:bottled water 759: 757: 752: 751: 746: 742: 735: 733: 731: 723: 721: 719: 714: 706: 699: 694: 687: 682: 679: 676: 673: 670: 669: 668: 665: 661: 659: 655: 654: 649: 627: 624: 620: 616: 607: 600: 598: 594: 586: 584: 582: 574: 572: 565: 563: 560: 552: 550: 548: 544: 541: 536: 534: 527:Sedimentation 526: 524: 522: 516: 512: 508: 506: 502: 501:sedimentation 498: 494: 489: 485: 481: 476: 474: 470: 466: 462: 458: 454: 450: 441: 436: 428: 426: 424: 423:sulfuric acid 420: 416: 415:carbonic acid 412: 408: 404: 400: 396: 392: 388: 384: 380: 376: 372: 368: 364: 360: 353:pH adjustment 352: 348:discontinued. 346: 343: 339: 335: 331: 328: 327: 326:screen filter 321: 317: 316: 312: 310: 307: 305: 296: 290: 283: 278: 277:Surface water 275: 272: 268: 264: 260: 257: 254: 250: 247: 244: 241: 238: 234: 231: 227: 223: 219: 215: 211: 207: 203: 199: 195: 191: 187: 183: 179: 175: 171: 167: 163: 159: 155: 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