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-as of [25 JULY 2024]–
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*a ‘water filter’ removes ‘im-purities’ by lowering ‘contamination’ of ‘water’ using either a…*
‘fine physical barrier’
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‘chemical process’
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‘bio-logical process’
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Filters cleanse water to different extents for purposes such as…
providing agricultural irrigation,
accessible drinking water,
public and private aquariums,
and the safe use of ponds and swimming pools
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Methods of filtration
Filters use sieving, adsorption, ion exchanges, biofilms and other processes to remove unwanted substances from water.
Unlike a sieve or screen, a filter can potentially remove particles much smaller than the holes through which its water passes
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Types
Water treatment plant filters
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Types of water filters include
media filters,
screen filters,
disk filters,
slow sand filter beds,
rapid sand filters,
cloth filters,[1]
and biological filters such as algae scrubbers
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Point-of-use filters
Point-of-use filters for home use include granular-activated carbon filters (GAC) used for carbon filtering, depth filter, metallic alloy filters, microporous ceramic filters, carbon block resin (CBR), microfiltration and ultrafiltration membranes.
Some filters use more than one filtration method
An example of this is a multi-barrier system. Jug filters can be used for small quantities of drinking water. Some kettles have built-in filters, primarily to reduce limescale build-up.
Standard Flowmatic cartridge style filters are added to existing plumbing; the filter cartridges are cylinders 10 inches (254 mm) long by 2.5 inches (64 mm) in diameter. They are made by multiple manufactures and are available in 0.5-100 micron ratings as well as activated carbon.
Some common substances that filtration does not remove are arsenic, bacteria, chlorides, fluoride, nitrates, perechlorates, pharmaceuticals, sodium and viruses.[2]
Portable water filters[edit]
Water filters are used by hikers,[3] aid organizations during humanitarian emergencies, and the military. These filters are usually small, portable and lightweight (1-2 pounds/0.5-1.0 kg or less), and usually filter water by working a mechanical hand pump, although some use a siphon drip system to force water through while others are built into water bottles. Dirty water is pumped via a screen-filtered flexible silicon tube through a specialized filter, ending up in a container. These filters work to remove bacteria, protozoa and microbial cysts that can cause disease. Filters may have fine meshes that must be replaced or cleaned, and ceramic water filters must have their outside abraded when they have become clogged with impurities.
These water filters should not be confused with devices or tablets that disinfect water which remove or kill viruses such as hepatitis A and rotavirus.
Certification in the United States[edit]
Three organizations are accredited by the American National Standards Institute, and each one of them certified products using American National Standard Institute/National Science Foundation standards. Each American National Standards Institute/National Science Foundation standard requires verification of contaminant reduction performance claims, an evaluation of the unit, including its materials and structural integrity, and a review of the product labels and sales literature. Each certifies that home water treatment units meet or exceed National Standard Institute/National Science Foundation and Environmental Protection Agency drinking water standards. American National Standard Institute/National Science Foundation standards are issued in two different sets, one for health concerns (such as removal of specific contaminants (Standard 53, Health Effects) and one for aesthetic concerns (Aesthetic Effects, such as improving taste or appearance of water). Certification from these organizations will specify one or both of these specific standards.
NSF International[edit]
NSF International as it is now known started out as the National Sanitation Foundation in 1944 at the University of Michigan School of Public Health.[4] The NSF’s water treatment Device Certification Program requires extensive product testing and unannounced audits of production facilities. One goal of this not for profit organization is to provide assurance to consumers that the water treatment devices they are purchasing meet the design, material, and performance requirements of national standards.[4]
Underwriters Laboratories[edit]
Underwriters Laboratories, Inc., is an independent, accredited testing and certification organization that certifies home water treatment units which meet or exceed EPA and American National Standard Institute/National Science Foundation drinking water standards of contaminant reduction, aesthetic concerns, structural integrity, and materials safety.
Water Quality Association[edit]
The Water Quality Association is a trade organization that tests water treatment equipment, and awards its Gold Seal to systems that meet or exceed ANSI/NSF standards for contaminant reduction performance, structural integrity, and materials safety.[5]
Filters that use reverse osmosis, those labeled as “absolute one micron filters,” or those labeled as certified by an American National Standards Institute (ANSI)- accredited organization to American National Standard Institute/National Science Foundation Standard 53 for “Cyst Removal” provide the greatest assurance of removing Cryptosporidium. As with all filters, follow the manufacturer’s instructions for filter use and replacement.[6]
Water polishing[edit]
The term water polishing can refer to any process that removes small (usually microscopic) particulate material, or removes very low concentrations of dissolved material from water. The process and its meaning vary from setting to setting: a manufacturer of aquarium filters may claim that its filters perform water polishing by capturing “micro particles” within nylon or polyester pads just as a chemical engineer can use the term to refer to the removal of magnetic resins from a solution by passing the solution over a bed of magnetic particulate.[7] In this sense, water polishing is simply another term for whole house water filtration systems. Polishing is also done on a large scale in water reclamation plants.[8]
History[edit]
2,000 years ago, Mayan drinking water filtration systems used crystalline quartz and zeolite. Both minerals are used in modern water filtration. “The filters would have removed harmful microbes, nitrogen-rich compounds, heavy metals such as mercury and other toxins from the water”.[9]
Persian engineer Al-Karaji (c. 953–1029) wrote a book, The Extraction of Hidden Waters, which gave an early description of a water filtration process.[10]
During the 19th and 20th centuries, water filters for domestic water production were generally divided into slow sand filters and rapid sand filters (also called mechanical filters and American filters). While there were many small-scale water filtration systems prior to 1800, Paisley, Scotland is generally acknowledged as the first city to receive filtered water for an entire town. The Paisley filter began operation in 1804 and was an early type of slow sand filter. Throughout the 1800s, hundreds of slow sand filters were constructed in the UK and on the European continent. An intermittent slow sand filter was constructed and operated at Lawrence, Massachusetts in 1893 due to continuing typhoid fever epidemics caused by sewage contamination of the water supply.[11] The first continuously operating slow sand filter was designed by Allen Hazen for the city of Albany, New York in 1897.[12] The most comprehensive history of water filtration was published by Moses N. Baker in 1948 and reprinted in 1981.[11]
In the 1800s, mechanical filtration was an industrial process that depended on the addition of aluminium sulfate prior to the filtration process. The filtration rate for mechanical filtration was typically more than 60 times faster than slow sand filters, thus requiring significantly less land area. The first modern mechanical filtration plant in the U.S. was built at Little Falls, New Jersey for the East Jersey Water Company. George W. Fuller designed and supervised the construction of the plant which went into operation in 1902.[13] In 1924, John R. Baylis developed a fixed grid backwash assist system which consisted of pipes with nozzles that injected jets of water into the filter material during expansion.[14]
See also[edit]
Backwashing (water treatment)
Carbon filtering
Distillation
Reverse osmosis
Reverse osmosis plant
Sand separator
Settling basin
Swimming pool sanitation
Water softening
Kinetic Degradation Fluxion Media
References[edit]
^ “Types of Filters”. Mountain Empire Community College. Retrieved 2008-10-01.
^ “Contaminant Reduction Claims Guide – NSF International”. Nsf.org. Retrieved 23 August 2018.
^ Leadem, Tim (2015-04-20). Hiking the West Coast of Vancouver Island: An Updated and Comprehensive Trail Guide. Greystone Books. ISBN 9781771641470.
^ Jump up to: a b “Mission, Values and History – NSF International”. Nsf.org. Retrieved 2016-06-30.
^ “Who We Are”. Lisle, IL: Water Quality Association. Retrieved 2018-05-02.
^ “Water Health Series: Filtration Facts”. Washington, D.C.: United States Environmental Protection Agency (EPA). September 2005. Brochure. 816-K-05-002.
^ “Water Polishing Process.” (Patent description.) Retrieved 2009-11-26.
^ “ALGAL TURF SCRUBBER SYSTEMS FOR POLLUTION CONTROL” (PDF). Hydromentia.com. Retrieved 2016-06-30.
^ “Ancient Maya built sophisticated water filters”. phys.org. Retrieved 2020-12-03.
^ Ataie-Ashtiani, Behzad; Simmons, Craig T. (15 August 2019). “The millennium old hydrogeology textbook The Extraction of Hidden Waters by the Persian mathematician and engineer Abubakr Mohammad Karaji (c. 953–c. 1029)”. Hydrology and Earth System Sciences Discussions: 1–19. doi:10.5194/hess-2019-407. ISSN 1027-5606.
^ Jump up to: a b Baker, Moses N. (1981). The Quest for Pure Water: the History of Water Purification from the Earliest Records to the Twentieth Century. 2nd Edition. Vol. 1. Denver: American Water Works Association, 64-80.
^ “Allen Hazen.” (1930). Jour. American Water Works Association. 22:9, 1268-70.
^ Fuller, George W. (1902). “The Filtration Works of the East Jersey Water Company, at Little Falls, New Jersey.” Transactions of the ASCE. 29 (February)): 153-202.
^ Baylis, John R. (1959). “Review of Filter Bed Design and Methods of Washing.” Journal AWWA. 51:11 1433-54.
External links[edit]
Media related to Water filters at Wikimedia Commons
en.wikipedia.org /wiki/Water_filter
Water filter
Contributors to Wikimedia projects10-13 minutes 6/27/2004
DOI: 10.5194/hess-2019-407, Show Details
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*FILTERED OR TAP?*
(lifehacker link)
lifehacker.com /do-i-need-to-drink-filtered-water-or-is-the-tap-okay-563167069
Do I Need to Drink Filtered Water or Is the Tap Okay?
Adam Dachis, Elizabeth Yuko6-8 minutes 10/17/2019
Image for article titled Do I Need to Drink Filtered Water or Is the Tap Okay?
Photo: Shutterstock
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There are a lot of different forms of drinking water out there:
tap,
bottled,
filtered,
the kind with added electrolytes—
the list goes on.
But do we really need to spend the money on fancy water, or is it OK straight from the tap? Here’s what you need to know.
—
Dear Lifehacker,
We have so many kinds of bottled water and filtering options.
While I prefer the taste over tap water, does it really matter?
Does tap water pose any risk, or can I drink it without cause for concern?
Sincerely,
Water Boggled
Dear W.B.,
Generally speaking—in most parts of the United States, at least—you can drink from the tap without any risk to your health.
If you choose to buy water, you should do so because you prefer the taste or because you fall into a small group of people who put themselves at risk by drinking tap water (more on this later).
But generally speakin, the water from your faucet will serve you well.
Here’s what you need to know.
G/O Media may get a commission
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Differences between water types
To learn more about the differences between water types and their health benefits (or lack thereof), we spoke with Dr. Carly Stewart—the medical expert over at Money Crashers. She explains:
There are three different types of drinking water to choose from: tap water, filtered water and bottled water. However, the differences between each type are less distinct than you might think. For example, according to the Natural Resources Defense Council, approximately 25 percent of bottled water is nothing more than bottled tap water. Also, federal regulations that govern the manufacturers of bottled water are typically much less strict than those regarding tap water.
Let’s break it down a bit more:
Tap water
And not all tap water is created equal. For instance, “city water” is regularly tested and treated to a certain standard, and may have additions like fluoride. “Well water,” on the other hand, comes from well, a well, and doesn’t undergo the same treatment and testing as its municipal counterpart. For this reason, people with compromised immune systems may be advised against drinking well water, though is generally safe for everyone else.
Filtered water
Filtered water is exactly what it sounds like: tap water that has gone through some sort of filter that can clear out many safety concerns like bacteria, heavy metals and pesticides. But it’s not as easy as buying a filter and automatically having perfect water. First, you have to figure out what you’re trying to filter out, and then buy the appropriate system. For example, if you want to get rid of bacteria, then a point-of-entry aerator—which uses high-pressure air jets to filter out contaminants that easily turn into gases—wouldn’t work. Don’t waste your money on an expensive filtration system unless you know exactly what you want to remove from your water.
Bottled water
Which brings us to bottled water. A 2019 study from the World Wildlife Fund International found that bottled water is no safer to drink than tap water, but can cost up to 1,000 times as much. And while most bottled water gets filtered, the water you drink may come from the tap in another location. So before you waste your money on what you already have in your home, check the bottle to learn how the water gets filtered. If it doesn’t say, it might just come from the tap.
Tap water-related health benefits and risks
In general, tap water provides the same health benefits as any other type of water: it keeps you hydrated, helps your blood flow, lubricates joints and other tissues, and is necessary for lots of the biological processes that keep us alive. Though, as Stewart explains, tap water may contain fluoride in some areas, which could help with oral health (but may not be doing as much as we initially thought it did).
So what about health risks? As we mentioned before, if you tap water comes from a well, then it may not be safe for people at high-risk of infection, like those undergoing chemotherapy, or who are HIV-positive or pregnant, Stewart explains. In those cases, she suggests consulting your doctor to figure out your best water option.
At this point we also need to mention that not all municipal water systems are doing enough to keep the local population safe, including in places like Flint, Michigan and parts of New Jersey. Of course, these are different situations and cases where tap water has been deemed unsafe—but it’s not the norm. Make sure to pay attention to any local alerts regarding your water. For example, you may receive notice that your community has a boil-water advisory, where it recommends that any drinking water is boiled before consumption, usually for a set, short-term basis after something like a water main break.
The bottom line: under most circumstances, tap water gets the job done.
What to do if you don’t like the flavor of your tap water
When you don’t like the way tap water tastes, but do enjoy filtered water in a bottle, you might think to turn to a filtration device. While it’ll cut out many contaminants, Stewart explains that you can’t get rid of everything:
Using a filtration device for your tap water can help if you don’t like the taste of it, as this removes certain contaminants, such as pesticide and chlorine residues. However, there are some chemicals that a filter cannot remove, such as nitrates and most home filtering systems are not designed to filter out bacteria or viruses.
As a result, if a traditional filter doesn’t do the trick (or you just find them frustratingly slow) you might want to try another solution, like a filtered water cooler. If you don’t want to spend much money, you might consider buying water flavorings at your grocery store or getting discount water in bulk from stores like Costco.
You may also prefer a non-standard filter. If you like Dasani water, for example, you can filter your water the same way. Reverse osmosis filters tend to produce a taste preferred by more people. They cost a bit more than your average screw-on filter or filter pitcher and require a bit more work, but cost far less than buying bottled water in the long run.
Regardless of how you go about it, most people don’t need to get water from any specific location.
Drink what best suits your tastebuds and your budget.
Love,
Lifehacker
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This story was originally published on 6/25/13 and was updated on 10/17/19 to provide more thorough and current information
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*👨🔬🕵️♀️🙇♀️*SKETCHES*🙇♂️👩🔬🕵️♂️*
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💕💝💖💓🖤💙🖤💙🖤💙🖤❤️💚💛🧡❣️💞💔💘❣️🧡💛💚❤️🖤💜🖤💙🖤💙🖤💗💖💝💘
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*🌈✨ *TABLE OF CONTENTS* ✨🌷*
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🔥🔥🔥🔥🔥🔥*we won the war* 🔥🔥🔥🔥🔥🔥