W

W

Waste Water

Water that has been used.   

1. (RO, ultrafiltration, electrodialysis) The stream of water (not product water) created as the result of processing water--the reject water or concentrate.  

2. (ion exchange and filtration) The spent water used in the total backwash/and or regeneration cycle. 3. The used water and solids from a residence or a community (including used water from industrial processes) that flow to a septic system or a treatment plant.   Storm water, surface water, and groundwater infiltration also may be included in the waste water that enters a waste water treatment plant. The term sewage usually refers to household wastes, but this word is being replaced by the term waste water.

Waste Water Treatment Plant

A facility that receives waste waters (and sometimes runoff) from domestic and/or industrial sources, and by a combination of physical, chemical, and biological processes reduces (treats) the waste waters to less harmful byproducts; known by the acronyms WWTP, STP (sewage treatment plant), and POTW (publicly owned treatment works).

Water

[H2O] An odorless, colorless, tasteless liquid which exists as ice in solid form (phase) and steam in vapor form (phase). It freezes at 32 degrees F (0 degrees C) and boils at 212 degrees F (100 degrees C). Water is a polar liquid with high dielectric constant which accounts for its solvent power; it is called the universal solvent. It is a weak electrolyte; in pure water, only about two molecules in every 1,100,000,000 separate into H3O+ and OH- ions. Water is only slightly compressible. It is the liquid that descends from the clouds as rain and forms lakes, streams, and seas (oceans). Water is a major constituent of all living matter. Also referred to as H2O (dihydrogen oxide) and HOH (hydrogen hydroxide).

Water Bloom

A prolific growth of plankton, including blue-green algae, which may occur and be so dense that it imparts a greenish, yellowish, or brownish color to water near the surface of a lake, pond, or reservoir.

Water Budget

A summation of inputs, outputs, and net changes to a particular water resource system over a fixed period. Also, water balance model.

Water Closet

A flushable toilet.

Water Conditioner

SEE water treatment device

Water Conditioning

SEE water treatment.

Water Cycle

SEE Hydrologic Cycle

Water Density (maximum)

The maximum density of water is reached at 39 degrees Fahrenheit (4 degrees Centigrade). It becomes less dense at both higher and lower temperatures.

Water Flooding

A process in underground mining such as oil recovery in which oil or a mineral from underground formations is replaced by an infusion of warm, softened water thus bringing the underground substance to the surface for recovery.     Also known as oil well flooding.

Water Flux

SEE Flux

Water Glass

The common name of a sodium silicate (Na2O x SiO2) substance used for corrosion control in potable waters. It is also an ingredient used in the manufacture of synthetic gel zeolite.  SEE ALSO silica.    It is also an ingredient used in the manufacture of synthetic gel zeolite.

Water Hammer

The shock wave or series of waves caused by the resistance of inertia to an abrupt change (acceleration or deceleration) of water flow through a water piping system.     Water hammer may produce an instantaneous pressure many times greater than the normal pressure.     For this reason, many building codes now require the installation of a "water hammer arrestor," a device to absorb these shock waves and prevent damage to appliances such as washing machines.

Water Head

SEE Head

Water Jacket

An outer casing which holds water or through which water flows and circulates to absorb heat and cool the interior of the mechanism or machinery that the water jacket is surrounding.

Water of Hydration

Water which has been chemically combined with a substance to form a hydrate and which can then be removed (as by heating) without essentially changing the chemical composition of the substance.

Water Processing

SEE Water Conditioning

Water Purveyor

An agency or person that supplies water (usually potable water).

Water Regain

SEE Water Retention

Water Retention

The amount of water, expressed as a percent of the wet weight of an ion exchanger, retained within the resin bead and on the surface of fully swollen and drained ion exchange media.     Also called water regain.

Water Softener

A device, product, or equipment that reduces the presence of water hardness to less than 1 gpg expressed as calcium carbonate (CaCO3) equivalent via chemical, physical, or other means. In residential and commercial applications, the most common water softener consists of a pressurized water treatment device in which hard water is passed through a bed of cation exchange media (either inorganic or synthetic organic) for the purpose of exchanging calcium and magnesium ions for sodium or potassium ions, thus producing a softened water which is more desirable for laundering, bathing, and dishwashing. This cation exchange process was originally called zeolite softening or the Permutit Process. Most modern water softeners use a sulfonated bead form of styrene/divinylbenzene (DVB) cation resin. Distillation, electrodialysis, nanofiltration, deionization, and reverse osmosis water treatment systems are also capable of measurably removing calcium and magnesium ions from water and therefore act as water softeners. SEE ALSO no-salt water softener; physical water treatment device.

Water Softener Salt

Salt suitable for regenerating residential and commercial cation exchange water softeners. Most commonly used for this purpose is sodium chloride (NaCl) in crystal or pelletized form. Rock grade salt should be 96-99 percent NaCl; evaporated salt should be 99+ percent NaCl.     Potassium chloride (KCl) may also be used for the regeneration cycle in the cation exchange process, thus minimizing the amount of sodium added to both the softened water and the spent regenerant water going to the drain.

Water Softening

A water treatment process for hard water whereby the concentration of hardness minerals is decreased.  The process, itself, does not necessarily produce soft water or softened water. SEE ALSO ion exchange; lime and soda ash softening; lime softening; water softener.

Water Solubility

The maximum concentration of a chemical compound which can result when it is dissolved in water. If a substance is water soluble, it can very readily disperse through the environment.

Water Source

The basic origin of a water, either a surface source (such as a lake, river, or reservoir) or a subsurface source (such as a well). After treatment and pumping via pipe lines, the treated and pumped water becomes a water supply.

Water Spotting

Cloudy milk-like film, spots, streaks, or heavy white deposits left on surfaces after water has dried from them, especially noticeable on clear glassware and cars after washing.     Spotting is caused by minerals that had been dissolved in the water remaining behind after the water has evaporated away.     Soft water spotting can be wiped off easily with a damp cloth or rinsed off with a little fresh water. Hard water deposits, on the other hand, are comprised of the more tenacious calcium and magnesium salts. Hard water films typically require harsh abrasives or an acid cleaner to remove them.     A third type of water residue film is due to silica (SiO2) deposits. Silica spotting is rare, but it is more difficult or impractical to be removed when it does occur.     If glassware films won't dissolve in acids such as vinegar or lemon juice, they may be due to silica spotting or etching. If the spot won't dissolve in acid, but can be scratched off with a razor blade or pinpoint, it's likely a silica film.

Water Spotting

Cloudy milk-like film, spots, streaks, or heavy white deposits left on surfaces after water has dried from them, especially noticeable on clear glassware and cars after washing.     Spotting is caused by minerals that had been dissolved in the water remaining behind after the water has evaporated away.     Soft water spotting can be wiped off easily with a damp cloth or rinsed off with a little fresh water. Hard water deposits, on the other hand, are comprised of the more tenacious calcium and magnesium salts. Hard water films typically require harsh abrasives or an acid cleaner to remove them.     A third type of water residue film is due to silica (SiO2) deposits. Silica spotting is rare, but it is more difficult or impractical to be removed when it does occur.     If glassware films won't dissolve in acids such as vinegar or lemon juice, they may be due to silica spotting or etching. If the spot won't dissolve in acid, but can be scratched off with a razor blade or pinpoint, it's likely a silica film.

Water Storage Pond

An impound for liquid wastes, so designated as to accomplish some degree of biochemical treatment of the wastes.

Water Supplier

A person who owns or operates a public water system.

Water Supply

SEE Water Source

Water Supply System

The collection, treatment, storage, and distribution of potable water from source to consumer.

Water Table

The level of groundwater. The upper surface of the zone of saturation of groundwater above an impermeable layer of soil or rock (through which water cannot move) as in an unconfined aquifer. This level can be very near the surface of the ground or far below it.

Water Treatment

Any method of purposefully changing the quality of water between its source and point of use.

Water Treatment Device

Any point-of-use or point-of-entry device that changes the quality of the water supply by any means, including, but not limited to, filtration, distillation, adsorption, ion exchange, reverse osmosis, or other treatment.

Water Treatment Lagoon

An impound for liquid wastes, so designed as to accomplish some degree of biochemical treatment of the wastes.

Water Well

An excavation where the intended use is for the location, acquisition, development, or artificial recharge of groundwater (excluding sandpoint wells).

Waterborne Disease

A disease, caused by a bacterium or organism able to live in water, which can be transmitted by water.

Waterborne Disease Outbreak

The significant occurrence of acute infectious illness, epidemiologically associated with the ingestion of water from a public water system that is deficient in treatment, as determined by the appropriate local or state agency.

Waterless Hand Cleaner

A paste, gel, or lotion that does not require rinsing. Waterless hand cleaners are useful when facilities for hand washing are not available and are also helpful in removing difficult soils.     Available for use from dispensers, or directly from their own containers, they are usually oil-in-water emulsions.     They are available with or without scrubbers. The scrubbers may be organic, (e.g., particles of polyethylene or polystyrene) or inorganic (pumice).

Waterlogged Tank

A tank (as in a domestic water well pumping system) in which too much water has accumulated and has replaced some of the air in the tank's air cushion causing a disruption in the normal pressure pattern needed for pumping and uniform water flow.

Watershed

The land area that drains into a stream. An area of land that contributes runoff to one specific delivery point; large watersheds may be composed of several smaller "subsheds," each of which contributes runoff to different locations that ultimately combine at a common delivery point.

Watertight

A condition existing in water treatment equipment and materials of such precision of construction and fit as to be impermeable to water unless sufficient pressure occurs to cause rupture.

Watt

A unit of power equal to one joule per second. The power of a current of one ampere flowing across a potential difference of one volt.

Weak Acid Cation Exchangers

Those cation exchange products with functional groups which, in the hydrogen form, are not capable of splitting neutral salts to form their corresponding free acids.  Weak acid cation exchange resins have a much higher (three to four times higher) regeneration efficiency than their strong acid counterparts, but in the hydrogen form can only exchange cations that are associated with alkalinity.  The cations associated with sulfates, chlorides, and nitrates, for example, cannot be removed with weak acid cation exchanger in the hydrogen form.  Hydrogen form weak acid cation exchangers that have been neutralized with sodium hydroxide to the sodium form, however, can effectively remove both carbonate and noncarbonate water hardness cations; thus weak acid cation resins can be used to soften waters that, because of high total dissolved solids, are not possible or practical to treat with strong acid cation resins.

Weak Base Anion Exchangers

Those anion exchange products with functional groups which are not capable of splitting neutral salts to form corresponding free bases.     Weak base anion exchange resins have a much higher (three to four times higher) regeneration efficiency than their strong base counterparts, but can only exchange mineral acid anions such as sulfate, chloride, and nitrate.     The anions associated with weak acids, such as carbonates, bicarbonates, silicates, and organic acids, for example, cannot be removed with weak base anion exchange.

Weight Concentration Ratio

In ultrafiltration applications, the ratio of the initial weight of the feedwater to the weight of the reject water remaining at any time during the ultrafiltration process.

Weir

1. A dam-like wall or plate placed in an open channel and used to measure the flow of water. The depth of the flow over the weir can be used to calculate the flow rate, or a chart or conversion table may be used. 

2. A wall or obstruction used to control flow (from settling tanks and clarifiers) to assure uniform flow rate and avoid short-circuiting.

Weir Diameter

Many circular clarifiers have a circular weir within the outside edge of the clarifier. All the water leaving the clarifier flows over this weir.     The diameter of the weir is the length of a line from one edge of a weir to the opposite edge and passing through the center of the circle formed by the weir.

Weir Loading

A guideline used to determine the length of weir needed on settling tanks and clarifiers in treatment plants. Used by operators to determine if weirs are hydraulically (flow) overloaded.

Well

A bored, drilled, or driven shaft, or a dug hole, whose depth is greater than the largest surface dimension and whose purpose is to reach underground water supplies or oil, or to store or bury fluids below ground.

Well Field

Area containing one or more wells that produces usable amounts of water.

Well Head

A particular well site location, as differentiated from other well site locations, that exist in the same water system.

Well Monitoring

The measurement, by on-site instruments or laboratory methods, of the quality of water in a well.

Well Plug

A watertight and gastight seal installed in a bore hole or well to prevent movement of fluids.

Wet Chemistry

Laboratory procedures used to analyze a sample of water using liquid chemical solutions (wet) instead of, or in addition to, laboratory instruments.

Wetlands

Any number of tidal and nontidal areas characterized by saturated or nearly saturated soils most of the year that form an interface between terrestrial (land-based) and aquatic environments; include freshwater marshes around ponds and channels (rivers and streams), brackish and salt marshes; other common names include swamps and bogs.

Wet-Salt Saturator Tank

A type of brine tank, so named because the saturated brine is always above the undissolved salt level, used on large commercial water softeners and older manual residential softeners.     Most automatic home-sized water softeners now use dry-salt saturator tanks.

Wetting Agent

A compound that increases the ability and speed with which a liquid displaces air from a solid surface, thus improving the process of wetting that surface. Wetting agents are all surfactants. They function by lowering surface and interfacial tension.     Soap and detergent surfactants serve as wetting agents in washing products, in addition to their other functions. In automatic dishwashing, nonionic surfactants are sometimes introduced into the last rinse for the purpose of maximizing drainage of water from dishes and utensils.

WFI

Water For Injection.

WHO

World Health Organization.

Whole-House Treatment

SEE Point-of-Entry (POE) Treatment

Wire-to-Water Efficiency

The efficiency of a pump and motor together.     Also called the overall efficiency.

Withdrawal

The process of taking water from a source and conveying it to a place for a particular type of use.

Withdrawal

The process of taking water from a source and conveying it to a place for a particular type of use.

Working Pressure

SEE Operating Pressure

World Health Organization (WHO)

A part of the United Nations. The WHO, which is headquartered in Geneva, Switzerland, has compiled recommended standards for drinking water.

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Updated on Mon, 09 Aug 2021 by Tanya

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