Water purification

purificationwater purifierpurifiedwater filtrationfiltration plantfiltrationwater treatmentpurify waterdrinking waterdrinking water treatment
Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water.wikipedia
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Activated carbon

activated charcoalactive carbonactive charcoal
The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.
Activated carbon is used in methane and hydrogen storage, air purification, solvent recovery, decaffeination, gold purification, metal extraction, water purification, medicine, sewage treatment, air filters in gas masks and respirators, filters in compressed air, teeth whitening, production of hydrogen chloride in dark and many other applications.

Ultraviolet germicidal irradiation

UV irradiationultraviolet disinfectionultraviolet light
The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.
UVGI is used in a variety of applications, such as food, air, and water purification.

Reverse osmosis

reverse-osmosisReverse Osmosis Water Purification UnitRO
The water is normally pre-treated with a reverse osmosis unit to remove non-ionic organic contaminants, and with gas transfer membranes to remove carbon dioxide.
Reverse osmosis (RO) is a water purification process that uses a partially permeable membrane to remove ions, unwanted molecules and larger particles from drinking water.

Water quality

qualitywaterchemical hydrology
The standards for drinking water quality are typically set by governments or by international standards.
In urbanized areas around the world, water purification technology is used in municipal water systems to remove contaminants from the source water (surface water or groundwater) before it is distributed to homes, businesses, schools and other recipients.

Slow sand filter

slow sand filtersslow sand filtrationFilter Beds
The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.
Slow sand filters are used in water purification for treating raw water to produce a potable product.

Rapid sand filter

rapid sand filtrationRapid gravity filterrapid gravity filtration
The most common type of filter is a rapid sand filter.
The rapid sand filter or rapid gravity filter is a type of filter used in water purification and is commonly used in municipal drinking water facilities as part of a multiple-stage treatment system.

Backwashing (water treatment)

backwashingbackwashBackwashing technology
To clean the filter, water is passed quickly upward through the filter, opposite the normal direction (called backflushing or backwashing) to remove embedded or unwanted particles.
In terms of water treatment, including water purification and sewage treatment, backwashing refers to pumping water backwards through the filters media, sometimes including intermittent use of compressed air during the process.

Sedimentation (water treatment)

sedimentationclarificationsedimentation tank
The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.
Sedimentation in potable water treatment generally follows a step of chemical coagulation and flocculation, which allows grouping particles together into flocs of a bigger size.

Synthetic membrane

membranemembranesartificial membrane
Ultrafiltration membranes use polymer membranes with chemically formed microscopic pores that can be used to filter out dissolved substances avoiding the use of coagulants.
The best known synthetic membrane separation processes include water purification, reverse osmosis, dehydrogenation of natural gas, removal of cell particles by microfiltration and ultrafiltration, removal of microorganisms from dairy products, and Dialysis.

Ion-exchange resin

ion exchange resinion-exchange resinsAmberlyst
Ion exchange: Ion exchange systems use ion exchange resin- or zeolite-packed columns to replace unwanted ions.
The most common examples are water softening and water purification.

Flocculation

flocculateagglomerationdeflocculant
The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.
Flocculation and sedimentation are widely employed in the purification of drinking water as well as in sewage treatment, storm-water treatment and treatment of industrial wastewater streams.

Water chlorination

chlorinationchlorinatedchlorine
The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.

Portable water purification

water purification tabletspoint of usePoint of use water treatment
Iodine is commonly used for portable water purification, and bromine is common as a swimming pool disinfectant.
Portable water purification devices are self-contained, easily transported units used to purify water from untreated sources (such as rivers, lakes, and wells) for drinking purposes.

Drinking water

potable waterpotableclean water
Most water is purified and disinfected for human consumption (drinking water), but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications.

Allen Hazen

In 1904, Allen Hazen 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.
From 1888 to 1893, Hazen headed the research team at this innovative research institute into water purification and sewage treatment.

Cryptosporidium

CryptosporidiidaeC. parvum'' lifecyclemicrobial parasite
For drinking water, membrane filters can remove virtually all particles larger than 0.2 μm—including giardia and cryptosporidium. 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.
Many treatment plants that take raw water from rivers, lakes, and reservoirs for public drinking water production use conventional filtration technologies.

Chlorine

Clchlorine gaschlorinated
The most common disinfection method involves some form of chlorine or its compounds such as chloramine or chlorine dioxide.
Chlorine is presently an important chemical for water purification (such as in water treatment plants), in disinfectants, and in bleach.

Ion exchange

ion-exchangecation exchangeanion exchanger
Ion exchange: Ion exchange systems use ion exchange resin- or zeolite-packed columns to replace unwanted ions.
A typical example of application is preparation of high-purity water for power engineering, electronic and nuclear industries; i.e. polymeric or mineralic insoluble ion exchangers are widely used for water softening, water purification, water decontamination, etc.

Zeolite

zeoliteszeoliticdachiardite
Ion exchange: Ion exchange systems use ion exchange resin- or zeolite-packed columns to replace unwanted ions.
Zeolites are widely used as ion-exchange beds in domestic and commercial water purification, softening, and other applications.

Clear well

After the introduction of any chemical disinfecting agent, the water is usually held in temporary storage – often called a contact tank or clear well – to allow the disinfecting action to complete.
A clear well (sometimes spelled as "clearwell") is a component of a municipal drinking water purification system.

Humic substance

humic acidhumichumic acids
The presence of humic acid in water intended for potable or industrial use can have a significant impact on the treatability of that water and the success of chemical disinfection processes.

Rainwater harvesting

water harvestingrain water harvestingrainwater collection
Solar panels can also be used for harvesting most of the rain water falling on them and drinking quality water, free from bacteria and suspended matter, can be generated by simple filtration and disinfection processes as rain water is very low in salinity.

Aluminium sulfate

aluminum sulfatealuminium sulphateAl 2 (SO 4 ) 3
The addition of inorganic coagulants such as aluminum sulfate (or alum) or iron (III) salts such as iron(III) chloride cause several simultaneous chemical and physical interactions on and among the particles.
Aluminium sulfate is used in water purification and as a mordant in dyeing and printing textiles.

Sand filter

sand filtrationsandsand-filter
Sir Francis Bacon attempted to desalinate sea water by passing the flow through a sand filter.
Sand filters are used as a step in the water treatment process of water purification.

Sodium hydroxide

caustic sodaNaOHsodium
If the water is acidic (lower than 7), lime, soda ash, or sodium hydroxide can be added to raise the pH during water purification processes.
Sodium hydroxide is sometimes used during water purification to raise the pH of water supplies.