Glossary of Terms

Glossary of Terms - A

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Alkylbenzene sulfonate
Generally means 100% retention of particulates of the size equal to the filter rating.
Filter rating meaning that 99.9 percent (or essentially all) of the particles larger than a specified micron rating will be trapped on or within the filter.
The amount of a chemical that enters the body of an exposed organism.
To take up or drink in, as a sponge imbibes water. The process of assimilation of molecules into the structure of a solid. One substance taken into the body of another substance
The fraction of a chemical making contact with an organism that is absorbed by the organism.
Estimate of the largest amount of chemical to which a person can be exposed on a daily basis that is not anticipated to result in adverse effects (usually expressed in mg/kg/day).
Water treatment equipment that when installed and operating is exposable and available for proper and thorough cleaning and inspection using only simple tools such as a screwdriver, pliers, or an open-end wrench. Equipment which is easily available for cleaning and inspection without having to use any tools at all is often referred to as readily accessible equipment.
A vessel or tank which receives and stores product water for use on demand.
How closely an instrument measures the true or actual value of the process variable being measured or sensed.
A substance which releases hydrogen ions when dissolved in water. Most acids will dissolve the common metals and will react with a bas to form a neutral salt and water.
Drainage of water from areas that have been mined for coal or other mineral ores; the water has low pH, sometimes less than 2.0 (is acid), because of its contact with sulfur-bearing material. Acid drainage is harmful because it often kills aquatic organisms.
Precipitation which has been rendered (made) acidic by airborne pollutants.
(uh-SID-ick) The condition of water or soil which contains a sufficient amount of acid substances to lower the pH below 7.0.
(uh-SID-uh-fe-KAY-shun) The addition of an acid (usually nitric or sulfuric) to a sample to lower the pH below 2.0. The purpose of acidification is to "fix" a water sample so it won't change until it is analyzed. The sample is then said to be "acidified."
The quantitative capacity of a water or water solution to neutralize an alkali or base. It is usually measured by titration with a standard solution of sodium hydroxide and expressed in terms of its calcium carbonate equivalent.
The volume of water which would cover an area of one acre to a depth of one foot. It is equal to 43,560 cubic feet or 325,851 gallons.
The concentration of lead or copper in water specified at Code of Federal Regulations 141.80(c) which determines, in some cases, the treatment requirements contained in subpart I of this code that a water system is required to complete.
A medium made by treating aluminum ore so that it becomes porous and highly adsorptive. Activated alumina will remove several contaminants including fluoride, arsenic, and selenium. This activated carbon medium requires periodic cleaning with an appropriate regenerant such as alum, acid, and/or caustic.
Adsorptive particles or granules usually obtained by heating carbonaceous material in the absence of air or in steam and possessing a high capacity to selesctivel remove trace and soluble components from solution.
Removal of soluble components from aqueous solution by contact with highly adsorptive granular or powdered carbon.
Activated carbon block is a blend of fine activated carbon (e.g., 80 X 325 mesh activated carbon), water, and a suitable binder (such as polyethylene or a similar material) that is mixed and molded and hardened or extruded to a cartridge filter of any size and shape. Sometimes specialized media are added along with activated carbon to provide customized performances for specific contaminants. The binder is particularly designed and chosen to hold the carbon and other media in a fixed solid matrix, yet, not to plug up the pores of the activated carbon. Even though the binder does occlude a portion of the adsorption sites, the finer mesh size gives activated carbon block filters faster adsorption kinetics and generally two to four times greater adsorption capacity than equivalent volumes of loose granular activated carbon. Activated carbon block filters typically have a 0.5 to 1 micron filtration capability, making it also helpful for particulate filtration, insoluble lead reduction, and demonstrating, in some cases, removal of Giardia and Cryptosporidium.
Treatment process in which water is brought into contact with highly adsorptive granular or powdered carbon to remove soluble components. Process may be applied to raw water, primary effluent, or chemically clarified wastewater for nonspecific removal of organics, or to secondary effluent as a polishing process to remove specific organcs.
A material usually formed from the reaction of a dilute silicate solution with a dilute acid and used as a coagulant aid.
An energy-expending mechanism by which a cell moves a chemical across the cell membrane from a point of lower concentration to a point of higher concentration, against the diffusion gradient.
A single exposure to a toxic substance which results in severe biological harm or death. Acute exposures are usually characterized as lasting no longer than a day.
The ability of a substance to cause poisonous effects resulting in severe biological harm or death soon after a single exposure or dose. Also, any severe poisonous effect resulting from a single short-term exposure to a toxic substance.
Combined effect of two or more chemicals equal to the sum of their individual effects.
The liquid, gas, or solid substance which is adsorbed as molecules, atoms, or ions.
A material, usually solid, capable of holding gases, liquids, and/or suspended matter at its surface and in exposed pores. Activated carbon is a common adsorbent used in water treatment.
The process in which matter adheres to the surface of an adsorbent.
The process in which air is brought into intimate contact with water, often by spraying water through air, or by bubbling air through water. Aeration may be used to add oxygen to the water for the oxidation of matter such as iron, or to cause the release of dissolved gases such as carbon dioxide or hydrogen sulfide from the water.
An action or process conducted in the presence of air, such as aerobic digestion of organic matter by bacteria.
Characteristics of water which affect its taste, odor, color, and appearance (and may affect the objects touched by the water) but which do not in themselves have any adverse health effects in otherwise potable water. Suggested Maximum Contaminant Levels (MCLs) for various aesthetic contaminants in drinking water are part of the National Secondary Drinking Water Regulations issued by the USEPA. These aesthetic standards are advisory only, not enforceable by the USEPA. See Also: Health Contaminant Drinking Water Drinking Water Standards Potable (Drinking) Water Safe Drinking Water Act (SDWA) Safe Water Club Soda Community Water System Zone of Saturation Bottled Artesian Water Bottled Distilled Water Bottled Fluoridated Water Bottled Mineral Water Bottled Natural Water Lime Soap Bottled Spring Water Brackish Water Brine Internal Water Treatment Ion Exchange Health Contaminant Drainage Basin Drinking Water Drinking Water Standards Municipal Water Permutit Process Phosphate Potable (Drinking) Water Etching External Water Treatment United States Pharmacopeia (USP) Water Softening WFI Sulfur (S) Safe Drinking Water Act (SDWA) Safe Water Sewage Silica Sodium Carbonate Softened Water Soft Water Health Contaminant Potable (Drinking) Water Safe Drinking Water Act (SDWA) Safe Water
A tank used to store a chemical solution of known concentration for feed to a chemical feeder. Also called a day tank.
The coalescence of dispersed suspended matter into larger flocs or particles which settle rapidly.
A mass or cluster of soil particles, often having a characteristic shape.
Synthetic chemicals (pesticides and fertilizers) used in agricultural production.
A situation where air enters the filter media. Air is harmful to both the filtration and backwash processes. Air can prevent the passage of water during the filtration process and can cause the loss of filter media during the backwash process.
A device which allows water, but not air, to pass through it. An air check is a typical component of a treatment system using a regenerant eductor.
A device used to dry out (desiccate) air by removing the water vapor. An air dryer may be used in ozone generation, for example, to produce higher concentrations of ozone and lessen the production of corrosive nitrous oxides.
A clear, vertical space between a water or drain line and the flood level of a receptacle used to prevent backflow or siphonage from the receptacle in the event of a negative pressure or vacuum. Most plumbing codes require the air gap to be at least twice the diamter of the water or drain line with a minimum of 11/2 inches.
Pumping dry air into a container to assist with the withdrawal of a liquid or to force a liquefied gas such as chlorine out of a container.
A technique for removal of volatile substances from a solution. Employs the principles of Henry's Law to transfer volatile pollutants from a solution of high concentration into an air stream of lower conentration. The process ordinarily is designed so that the solution containing the volatile pollutant contacts large volumes of air.
A switch that operates when some preset low, high, or abnormal condition exists.
A class of organic coumounds containing one or more hydroxly groups (OH)
Small primitive plants containing chlorophyll commonly found in surface water. Excessive growths may create taste and odor problems and consume dissolved oxygen during decay.
Sudden, massive growths of microscopic and macroscopic plant life, such as green or blue-green algae, which develop in lakes and reservoirs.
Any substance or chemical specifically formulated to kill or control algae.
A type of organic compound in which the characteristic chemical groups are linked to a straight or branched carbon chain, as opposed to a carbon ring structure. In complex structures, the chains may also be cross-linked. See Also: Heterocyclic Organic Aromatic Organic
Organic acids with carbon atoms arranged in branched or unbranched open chains rather than in rings.
Portion of a sample.
A group of water soluble mineral compounds usually considered to have moderate strengths as bases as opposed to the causic or stongly basic hydroxides, although this differentiation is not always made. In general, the term is applied to the carbonates, borates, phosphates, and silicates when these are present in the water or solution.
The condition of water or soil which contains a sufficient amount of alkali substances to raise the pH above 7.0.
The quantitative capacity of a water or water solution to neutralize an acid. It is usually measured by titration with a standard acid solution of a sulfuric acid and expresssed in terms of its calium carbonate equivalent.
There are three different tests used for testing alkalinity, usually performed in this order: The pH alkalinity test will indicate the presence or absence of hydroxide alkalinity. A pH reading of 8.3 or above indicates the presence of hydroxide alkalinity. The phenolphthalein test measures "P alkalinity" which is made up of all hydroxide alkalinity plus 1/2 of the carbonate alkalinity. The Methyl Orange test measures the "M alkalinity" which is the remaining 1/2 of the carbonate alkalinity plus all of the bicarbonate alkalinity. See Also: Base Alkali Alkalinity Hydroxide Alkalinity Detergent Methyl Orange Methyl Orange Alkalinity Phenolphthalein Phosphate Soap Base Alkali Alkalinity Hydroxide Alkalinity Detergent Methyl Orange Methyl Orange Alkalinity Phenolphthalein Phosphate Soap
A generic term covering a wide range of anionic surfactants and detergent processing aids. The alkylaryl sulfonates of primary interest to the detergent industry are the surfactants classified as linear alkylate sulfonates, usually sodium salts, and the processing aids ammonium, potassium, or sodium salts of toluene, xylene, or cumene sulfonates. They are used to solubilize the active ingredients in some liquid detergents. See Also: Linear Alkyl Sulfonate (LAS) Linear Alkyl Sulfonate (LAS) Alkylbenzene Sulfonate (ABS) Alkylbenzene Sulfonate (ABS) Alkylbenzene Sulfonate (ABS) Linear Alkyl Sulfonate (LAS) Alkylbenzene Sulfonate (ABS) Alkylbenzene Sulfonate (ABS) Emulsification Wetting Agent
A major class of aklylaryl sulfonate surfactants used in detergents; usually a sodium salt. ABS is anionic and high sudsing. Prior to the mid-1960s, the form of ABS most widely used in detergent formulations resisted biodegradation. In 1965, detergent manufacturers voluntarily replaced ABS nationally in household laundry products by a more rapidly biodegradable variety of ABS called linear alkylate sulfonate, or LAS. SEE ALSO alkylaryl sulfonate; linear alkylate sulfonate; surfactant. See Also: Linear Alkyl Sulfonate (LAS) Alkylaryl Sulfonate Alkylaryl Sulfonate Alkylaryl Sulfonate Linear Alkyl Sulfonate (LAS) Alkylaryl Sulfonate Alkylaryl Sulfonate Emulsification Wetting Agent
One of several possible forms of a substance. Ozone [O3] is a triatomic allotrope of oxygen (O2).
Relating to mud and/or sand deposited by flowing water. Alluvial deposits may occur after a heavy rainstorm.
An electric current that reverses its direction (positive/negative values) at regular intervals.
A dual automatic softener system functioning with one unit in service and one on standby. When a predetermined gallonage of softened water has passed or when a monitor detects hard water breakthrough, the idle or standby unit automatically goes into service. The spent unit then regenerates and becomes the idle/standby unit.
A common name for aluminum sulfate (Al2(SO4)3, used as a coagulant.
A stable, natural, glassy aluminum silicate mineral from volcanic ash which is used as a water treatment filtration medium. See Also: Pumicite Pumicite Pumicite Pumicite
Environmental or surrounding conditions.
A group of compounds formed by the reaction of an organic acid with ammonia or an amine.
An alkaline gas composed of nitrogen and hydrogen (NH3).
A small, single-celled animal or protozoan.
The strength of an electric current measured in amperes. The amount of electric current flow, analgous to the flow of water in gallons per minute.
The unit used to measure current strength. The current produced by an electromotive force of one volt acting through a resistance of one ohm.
Based on the electric current that flows between two electrodes in a solution.
A condition in which there is no air or no available free oxygen.
An organism that can thrive in the absence of oxygen (air), such as bacteria in a septic tank.
The readout of an instrument by a pointer (or other indicating means) against a dial or scale.
A device which conducts periodic or continuous measurement of some factor such as chlorine, fluoride, or turbidity. Analyzers operate by any of several methods including photocells, conductivity or complex instrumentation.
Unit of wavelength of light equal to one tenth of a millimicron or one ten millionth of a millimeter.
Investigations using animals as surrogates for humans on the expectation that results in animals are pertinent to humans.
A negatively charged ion in solution such as bicarbonate, chloride, or sulfate.
See Ion Exchange Membrane.
A polymer having negatively charged groups of ions; often used as a filter aid and for dewatering sludges.
A ring-shaped space located between two circular objects, such as two pipes.
The positive pole of an electrolytic system; the metal which goes into solution in a galvanic cell. Anodes of metals such as magnesium or zinc are sometimees installed in water heaters or other tanks to deliberately establish galvanic cells to control corrosion of the tank through the sacrifice of the anode.
Interference or inhibition of the effect of one chemical by the action of another chemical.
A filter medium produced from crushed anthracite coal and screened to specific mesh sizes.
anti, against + sepsis, decay. Preventing or inhibiting the growth and multiplication of microorganisms, especially pathogenic microorganisms, without necessarily destroying them. See Also: Aseptic Aseptic Procedure Sterilize Sterilization Aseptic Aseptic Procedure Sterilize Sterilization Aseptic Aseptic Aseptic Procedure Disinfect Disinfection Sterilize Sterilization Sanitization Sanitize Aseptic Aseptic Procedure Disinfect Sterilize Sanitization Sanitizer Biocide Aseptic Aseptic Procedure Disinfect Sporicide Sanitization Sanitize
Advanced Oxidation Process.
Water rights to or ownership of a water supply which is acquired for the beneficial use of water by following a specific legal procedure.
Machinery, appliances, structures, and other parts of the main structure necessary to allow it to operate as intended, but not considered part of the main structure.
Plants or animal life living in, growing in, or adapted to water.
(A-kwee-us) Something made up of, similar to, or containing water; watery.
A layer or zone below the surface of the earth which is capable of yielding a significant volume of water.
A form of calcium carbonate that appears in pearls.
A type of organic compound in which the characteristic chemical groups are linked to a particular type of six-member hexagonal carbon ring which contains three double bonds, typified by benzene. Such rings have peculiar stability and chemical character, and are present in the rather reactive and highly versatile compounds derived from petroleum and coal tar. The name refers to the strong and not unpleasant odor characteristic of most substances of this nature. See Also: Organic Heterocyclic Organic Aliphatic
(are-TEE-zhun) Water held under pressure in porous rock or soil confined by impermeable geologic formations. An artesian well is free flowing. See Also: Confined Aquifer
a, not + sepsis, decay. 1. Free or freed from pathogenic organisms and their toxins. 2. A sterile condition, free from germs, infection, and any form of life. See Also: Aseptic Procedure Antiseptic Aseptic Procedure Sterilize Sterilization Antiseptic Antiseptic Aseptic Procedure Disinfect Disinfection Sterilize Sterilization Sanitization Sanitize Antiseptic Aseptic Procedure Disinfect Sterilize Sanitization Sanitizer Biocide Antiseptic Aseptic Procedure Disinfect Sporicide Sanitization Sanitize
A method used to prevent microbial contamination; equipment and tools are cleaned and sanitized, disinfected, or sterilized; personnel wear sanitary or sterilized gloves and sometimes clean caps and masks. See Also: Aseptic Antiseptic Aseptic Sterilize Sterilization Antiseptic Aseptic Disinfect Disinfection Sterilize Sterilization Sanitization Sanitize Antiseptic Aseptic Disinfect Sterilize Sanitization Sanitizer Biocide Antiseptic Aseptic Disinfect Sporicide Sanitization Sanitize
A device which creates movement of air, liquids, and granular substances by suction.
A test for a particular chemical or effect.
See Reagent Grade Water. Reagent grade water is used for chemical analysis and physical laboratory testing.
Not similar in size, shape, form, or arrangement of parts on opposite sides of a line, point, or plane.
The smallest particle of an element that can exist either alone or in combination with similar particles of the same element or of a different element.
A spectroscopy chemical analytical technique used for determining the metal elements in water by measuring the well-defined characteristic light wave lengths absorbed by each respective element when the element has been thermally excited into an atomic vapor. The sample to be analyzed is atomized into an atomic vapor by either aspirating the sample into a specific flame (in flame AA) or by vaporization with a tube of graphite that is electrically heated to a temperature between 1500 and 2800 degrees C (in flameless AA). A light beam of specific characteristic wave lengths is directed through the vapor, into a monochromator that further defines the very small range of wave lengths to be analyzed, and into a detector that measures the amount of light absorbed by the atomized element. Identification of the element is possible because each element has its own well-defined characteristic absorption wave length. The amount of absorbance measured is proportional to the concentration of the element in the sample. See Also: Fahrenheit Induced Infiltration Spectroscopy AAMI Grade Water Spectrometer Induced Infiltration Spectroscopy Emission Spectroscopy
The process in which solids are worn down or ground down by friction often between particles of the same material. Filter media are subject to attrition during backwashing, regeneration and service.
A cleaning product designed specifically for use in automatic dishwashers. It must produce little or no suds or foam because too much foam can inhibit the washing action. Its important functions include the following: Tie up water hardness minerals to permit the detergent to do its cleaning job. Make water wetter (reduce surface tension) to penetrate and loosen soil. Emulsify greasy or oily soil. Suppress foam caused by protein soils such as egg and milk. Help water to sheet off surfaces, thus minimizing water spots. Protect china patterns and metals from the corrosive effects of heat and water alone. Basic ingredients in most automatic dishwasher detergents include: Surfactant (nonionic) - lowers the surface tension of water so that it will more quickly wet out the surfaces and the soils, thus allowing water to sheet off dishes and not dry in spots. The surfactant also helps remove and emulsify fatty soils like butter and cooking fat. Nonionic surfactants are used because they generally have the lowest sudsing characteristics. Builder (complex phosphates) - combines with water hardness minerals (primarily calcium and magnesium) and holds them in solution so that the minerals cannot combine with food soils and so that neither the minerals themselves nor the mineral/food soil combination will leave insoluble spots or film on dishes. Corrosion inhibitor (sodium silicate) - helps protect machine parts, prevent the removal of china patterns, and the corrosion of metals such as aluminum. Fragrance (optional) - covers the chemical odor of the base product and stale food odors. Oxidizing agent - helps break down protein soils like egg and milk, aids in removing such stains as coffee or tea, and lessens spotting of glassware. Processing aids - generally inert materials that allow the active ingredients to be combined into a usable form. Suds suppressor - controls foam from food soils, especially protein soils.
A water softener (or filter) that is equipped with a clock timer which automatically initiates the backwash and/or regeneration process at certain preset intervals of time. All operations, including bypass of treated or untreated water (depending upon design), backwashing, brining, rinsing, and returning the unit to service are performed automatically.
auto, self + trophe, nourishment. Capable of obtaining food or nourishment from simple raw materials. Autotrophic organisms or autotrophs are organic compound producers such as algae, plants, and certain bacteria that use carbon dioxide or carbonates, inorganic nitrogen, water, and an energy source such as photosynthesis from sunlight to make (or synthesize) complex molecules. Opposite of heterotrophic. See Also: Heterotrophic Microorganisms
A measure of the amount of chlorine available in chlorinated lime, hypochlorite compounds, and other materials that are used as a source of chlorine when compared with that of elemental (liquid or gaseous) chlorine.
The vertical distance from the sand surface to the underside of a trough in a sand filter. This distance is also called freeboard.
The number of molecules in a gram-molecular weight or the number of atoms in a gram-atomic weight of any substance: its value being 6.023 x 10E23. For example, oxygen with an atomic weight of 16 has 6.023 x 10E23 atoms in 16 grams.
See Longitudinal Flow
The direction in which material being pumped flows around the impeller or flow parallel to the impeller shaft.
An imaginary line running along the center of a shaft (such as an impeller shaft).