Filter (water)

Information about Filter (water)

An industrial water filter with geared motor

A water filter is a device which removes impurities from water by means of a fine physical barrier, chemical processes and/or biological process. Filters are used to cleanse water for irrigation, drinking water, aquariums, and swimming pools.

Water filters are primarily used to soften water and remove chemicals such as chlorine. Some scientists believe that the contaminants found in drinking unfiltered drinking water can be harmful to your health, even increasing the risk of developing cancer. The most common problem with unfiltered water, however, is a bad taste or smell.

Water filters are also used by recreational hikers, by aid organizations during humanitarian emergencies, and by the military. These filters are usually small, portable and light (1-2 pounds or less) and usually filter water by working a mechanical hand pump, although some use a siphon drip system to force water through. Dirty water is pumped via a screen-filtered flexible silicon tube through a specialized filter, ending up in a water bottle (or other container, such as a Camel Back). These types of filters work to remove bacteria, protozoa and cysts, all of which can cause disease. Popular and reliable makers of these small, portable water filters include General Ecology, Innova Pure Water, Katadyn,Mountain Safety Research, and Pure Water 2GO. Filters include fine meshes, which must be replaced, and ceramic filters which must have their outside abraded off when it becomes clogged with impurities.

These water filters should not be confused with devices or tablets that are water purifiers. Water purifiers satisfy higher EPA standards, and also remove viruses, such as hepatitis A and rotavirus, among others.

In a domestic emergency, where water needs will last beyond those of stored, bottled water, a device that is specifically certified as a water purifier, and not a water filter, is preferred.

The physics of filters is based on sieving, adsorption, ion exchanges and other processes. Unlike a sieve or screen, a filter can remove particles much smaller than the holes through which the water passes.

Examples

External links

History of Water Filters - History of water and water treatment.
Types of Filters - a comparison of the Slow sand filter, Rapid sand filter, Pressure filter & Diatomaceous earth filter. (Mountain Empire Community College, Water/Wastewater Distance Learning)
Filtration info from New Mexico State University

Water is a common chemical substance that is essential to all known forms of life.^[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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Irrigation is the artificial application of water to the soil usually for assisting in growing crops. In crop production it is mainly used to replace missing rainfall in periods of drought, but also to protect plants against frost.
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Drinking water is water that is intended to be ingested by humans. Water of sufficient quality to serve as drinking water is termed potable water whether it is used as such or not.
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aquarium (plural aquariums or aquaria) is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Aquaria are primarily used for fishkeeping, although invertebrates, amphibians, marine mammals, and aquatic plants
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swimming pool(3,000L), swimming bath(500L), or wading pool(30 L) is an artificially enclosed body of water intended for swimming or water-based recreation. There are many standard sizes; the largest and deepest is the Olympic size.
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1, 3, 5, 7
(strongly acidic oxide)
Electronegativity 3.16 (Pauling scale)
Ionization energies
(more) 1st: 1251.2 kJmol⁻¹
2nd: 2298 kJmol⁻¹
3rd: 3822 kJmol⁻¹

Atomic radius 100 pm
Atomic radius (calc.
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siphon (also spelled syphon) is a continuous tube that allows liquid to drain from a reservoir through an intermediate point that is higher than the reservoir, the up-slope flow being driven only by hydrostatic pressure without any need for pumping.
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Mountain Safety Research, Inc.

Subsidiary of Cascade Designs
Founded 1969
Headquarters Seattle, Washington, USA

Key people Larry Penberthy, Founder
Industry sporting goods and outdoor gear
Website http://www.msrgear.
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ceramic is derived from the Greek word κεραμικός (keramikos). The term covers inorganic non-metallic materials which are formed by the action of heat.
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Water purification is the process of removing contaminants from a raw water source. The goal is to produce water for a specific purpose with a treatment profile designed to limit the inclusion of specific materials; most water is purified for human consumption (drinking water).
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Adsorption is a process that occurs when a gas or liquid solute accumulates on the surface of a solid or, more rarely, a liquid (adsorbent), forming a molecular or atomic film (the adsorbate).
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Ion exchange is an exchange of ions between two electrolytes or between an electrolyte solution and a complex. In most cases the term is used to denote the processes of purification, separation, and decontamination of aqueous and other ion-containing solutions with solid polymeric
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In general, a sieve separates wanted/desired elements from unwanted material using a tool such as a mesh, net or other filtration or distillation methods. The word "sift" derives from this term.
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Screen may mean:

Window screen, a wire mesh that covers a window opening
Fire screen
Windshield (windscreen), protects the driver of a vehicle
Screen-printing (silk-screening), a method of printing
Projection screen, a viewing surface

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A media filter is a type of filter utilizing a bed of sand, crushed granite or other material to filter water for drinking, swimming pools, aquaculture, irrigation, and other applications.
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A screen filter is a type of filter utilizing a rigid or flexible screen to separate sand and other fine particles out of water for irrigation or other applications. These are generally not recommended for filtering out organic matter such as algae, since these types of
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A disk filter is a type of water filter used primarily in irrigation, similar to a screen filter, except that the filter cartridge is made of a number of disks stacked on top of each other like a pile of poker chips.
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Slow sand filters are used in water purification for treating raw water to produce a potable product. They are typically 1 to 2 metres deep, can be rectangular or cylindrical in cross section and are used primarily to treat surface water.
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The rapid sand filter or rapid gravity filter is a type of filter used in the purification of water and is commonly used in municipal water treatment facilities.
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cloth filter is a simple and cost-effective appropriate technology method for reducing the contamination of drinking water. Water collected in this way has a greatly reduced pathogen count - though it will not necessarily be perfectly safe, it is an improvement for poor people with
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Backwash is the backwards flow of air or water. Backwash can be created naturally by waves rebounding off a beach or other obstacle. It is created by propulsion devices such as an oar or engine.
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Reverse osmosis is a separation process that uses pressure to force a solvent through a membrane that retains the solute on one side and allows the pure solvent to pass to the other side.
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Distillation is a method of separating chemical substances based on differences in their volatilities in a boiling liquid mixture. Distillation usually forms part of a larger chemical process, and is thus referred to as a unit operation.
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A sand separator or hydro cyclone is a device which utilizes centrifugal force to separate sand or other heavy particles out of water. The separated material drops down into a tank or reservoir where it can be removed later or in the case of in-well separators, the
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A settling basin, settling pond or decant pond is a place where very fine particles from water are removed by means of gravity. The dirty water enters the basin at one end and the cleaner water is taken out at the other end by decanting.
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Swimming pool sanitation refers to both visual clarity and levels of microflora, such as bacteria and viruses in swimming pools. The goal of sanitation is to prevent the spread of diseases and pathogens between users.
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Mountain Empire Community College is a two-year college located in Big Stone Gap, Virginia, and is one of the 23 schools in the Virginia Community College System. The college serves residents of Dickenson, Lee, Scott, and Wise counties, as well as the City of Norton.
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