Glossary of Terms - S
A :B :C :D :E :F :G :H :I :J :K :L :M :N :O :P :Q :R :S :T :U :V :W :X :Y :Z :
An anode made of suitable metal placed in a water heater tank to protect the tank from corrosion. Anodes of metals such as aluminum, magnesium, or zinc are sometimes installed in water heaters and other tanks to control corrosion of the tank. The introduction of the anode creates a galvanic cell in which the magnesium or zinc will go into solution (be corroded) more quickly than the metal of the tank, thereby imparting a cathodic (negative) charge to the tank metal(s) and thus preventing tank corrosion.
This corroding of the anode metal is called "the sacrifice of the anode".
Condition of exposure under which there is a "practical certainty" that no harm will result in exposed individuals.
The national legislation first passed by the U.S. Congress and signed into law by the President in 1974 and amended in 1986.
The SDWA directs the U.S. Environmental Protection Agency to promulgate and enforce standards for safe drinking water necessary to protect public health at public water systems serving 25 or more people for an average of 60 days per year.
The law also contains provision for delegating primary enforcement responsibility to states and for protecting underground sources of drinking water.
See Also: Aesthetic Contaminants Health Contaminant Drinking Water Drinking Water Standards Potable (Drinking) Water 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 Aesthetic Contaminants 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 Water Sewage Silica Sodium Carbonate Softened Water Soft Water Aesthetic Contaminants Health Contaminant Potable (Drinking) Water Safe Water
Water that does not contain harmful bacteria, or toxic materials or chemicals. Water may have taste and odor problems, color and certain mineral problems and still be considered safe for drinking.
See Also: Aesthetic Contaminants Health Contaminant Drinking Water Drinking Water Standards Potable (Drinking) Water Safe Drinking Water Act (SDWA) 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 Aesthetic Contaminants 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) Sewage Silica Sodium Carbonate Softened Water Soft Water Aesthetic Contaminants Health Contaminant Potable (Drinking) Water Safe Drinking Water Act (SDWA) Drinking 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 Aesthetic Contaminants 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) Sewage Silica Sodium Carbonate Softened Water Soft Water
The annual quantity of water that can be taken from a source of supply over a period of years without depleting the source beyond its ability to be replenished naturally in "wet years."
Spanish name for sea salt.
A hydrometer which measures the percent of salt as NaCl in brine or other salt solutions. A 100 percent reading on a salimeter is about 26.4 percent salt by weight at 60 degrees F. Some people use the term "salinometer" to refer to a salimeter.
Consisting of, or containing, salt.
Any solution with the total dissolved solids (TDS) usually ranging from 15,000 to 30,000 mg/L.
For example, a solution of sodium chloride and water, usually containing other salts also.
May also be called saline water.
The relative concentration of dissolved salts, usually sodium chloride, in a given water. A measure of the concentration of dissolved mineral substances in water.
An instrument for determining the salt concentration (salinity) of brine water by measuring the electrical conductivity of the solution.
A salinometer is sometimes called a salt gauge.
1. Chemistry A chemical compound formed by the neutralization of an acid with a base. For example, H2SO4 (acid) + 2NaOH (base) = Na2SO4 (salt) + 2H2O (water). 2. Water Treatment Sodium chloride (NaCl) or potassium chloride (KCl), both of which are used in solution form to regenerate cation exchange water softeners and some dealkalizers. 3. Common table salt, which is sodium chloride (NaCl).
See Also: Sodium Chloride (NaCl) Common Salt Brackish Water Brine Dry-Salt Saturator Tank Wet-Salt Saturator Tank Sodium Chloride (NaCl)
Evaporated salt or fine rock salt which is mechanically compressed into dense blocks, weighing about 50 pounds each, which are sometimes used in residential water softeners.
The creation of salt encrustment and cementing together of salt particles in dry storage brine tanks which causes tight bonding of the entire salt mass to the walls of the brine tank and prevents the salt from dropping into the incoming water for brine makeup.
See Also: Mushing
Sodium sulfate (Na2SO4) which is only 90-99 percent pure (i.e., contains 1-10 percent of substances other than Na2SO4).
Salt cake is made by heating rock salt with sulfuric acid, producing muriatic acid and salt cake.
In an ion exchange water softener, the hardness removal capacity calculated as grains of hardness removed divided by the weight of salt in pounds that is used to achieve that amount of hardness reduction.
Operational salt efficiency refers to the salt efficiency performance of a water softener under conditions of actual or simulated long term use (six months or more) in a household where gallons of water usage typically varies from day to day.
An ion exchange process in which neutral salts in water are converted to their corresponding acids or bases.
A strong base anion exchanger resin can convert a salt solution to caustic (base) (for example, NaCl + ROH = RCl + NaOH); and a strong acid cation exchanger can convert a salt to acid (for example, NaCl + HR = NaR + HCl).
A regular test used on an ion exchange resin to determine the capacity of a used resin versus the standard rated capacity of the resin when fresh.
The general term for all water over 1,000 ppm (mg/L) total dissolved solids.
Fresh Water - <1,000 TDS
Brackish - 1,000-5,000 TDS
Highly Brackish - 5,000-15,000 TDS
Saline - 15,000-30,000 TDS
Sea Water - 30,000-40,000 TDS
Brine - 40,000-300,000+ TDS
Soil particles between 0.05 and 2.0 mm in diameter.
The oldest and most basic filtration process, which generally uses two grades of sand (coarse and fine) for turbidity removal or as a first stage roughing filter or prefilter in more complex processing systems.
Municipal water treatment systems often used gravity rapid-rate sand filters. Pressure-type sand filters plus coagulants are used for commercial applications.
For home use or for small swimming pools, a pressure sand filter is also used.
A mechanical device to separate fine sand or other abrasive material from water in wells with faulty screens. The hydrocyclone separator is one form of a sand trap.
A sewer that transports only waste waters (from domestic residences and/or industries) to a waste water treatment plant.
An on-site review of the water source, facilities, equipment, operation, and maintenance of a public water system for the purpose of evaluating the adequacy of the facilities for producing and distributing safe drinking water.
The act of sanitizing. Sanitization is not an absolute phenomenon; it is a partial removal or inactivation of microorganisms. Depending on the system, a sanitization operation should reduce the viable organism population by 50 to 99.9 percent, but it should completely eliminate enteric pathogen-related organisms such as Salmonella and E. coli.
(Disinfection by comparison, should reduce 99.9 to 99.9999 percent of viable microorganisms.)
See Also: Antiseptic Aseptic Aseptic Procedure Disinfect Disinfection Sterilize Sterilization Sanitize Antiseptic Aseptic Aseptic Procedure Disinfect Sterilize Sanitizer Biocide Antiseptic Aseptic Aseptic Procedure Disinfect Sporicide Sanitize
To reduce the number of bacterial contaminants to safe levels as judged by public health requirements. To make clean and free or inactivation of dirt, filth, and conditions injurious to health.
Generally considered to reduce germ count by 50 to 99.9 percent.
The USEPA requires that sanitizing claims must show a 99.9 percent microbial reduction in five minutes.
See Also: Antiseptic Aseptic Aseptic Procedure Disinfect Disinfection Sterilize Sterilization Sanitization Biocide Antiseptic Aseptic Aseptic Procedure Disinfect Sporicide Sanitization
An agent that results in the reduction of bacterial numbers to accepted public health limits by sanitizing. Sanitizers are applied in the cleaning operations of inanimate objects.
See Also: Antiseptic Aseptic Aseptic Procedure Disinfect Sterilize Sanitization
Organisms living on dead or decaying organic matter. They help natural decomposition of organic matter in water.
A solution which contains the maximum amount of the dissolved substance (solute) that a solution of this kind can normally hold at this temperature.
The area below the water table where all open spaces are filled with water.
In water chemistry, means the state of a solution (water) when it holds the maximum equilibrium quantity of dissolved matter at a given temperature and pressure. The limit when no more of a given substance will dissolve.
A device which produces a fluoride solution for the fluoridation process. The device is usually a cylindrical container with granular sodium fluoride on the bottom. Water flows either upward or downward through the sodium fluoride to produce the fluoride solution.
A coating or precipitate deposited on surfaces such as kettles, water pipes, or steam boilers that are in contact with hard water.
Waters that contain carbonates or bicarbonates of calcium or magnesium are especially likely to cause scale when heated.
Also called hard water scale.
In water treatment applications, a polymer matrix or ion exchanger that is used specifically to remove organic species from the feedwater before the water is to pass through the deionization process.
Cubic feet of air per minute at standard conditions of temperature, pressure, and humidity (0 degrees C/14.7 psia/50% relative humidity).
A sizing system of arbitrary numbers that specifies the I.D. (inside diameter)and O.D. (outside diameter) for each diameter pipe. This term is sued for steel, wrought iron, and some types of plastic pipe. Also used to describe the strength of some types of plastic pipe.
See Safe Drinking Water Act.
(SECK-key) Disc - A flat, white disc lowered into the water by a rope until it is just barely visible. At this point, the depth of the disc from the water surface is the recorded seechi disc transparency.
See Drinking Water Standards.
As relates to waste water treatment, the process which makes up the second step in treating waste water and removes suspended and dissolved solids and biochemical oxygen demand (BOD) from the waste water which has already undergone primary treatment.
The quantity of sediment arriving at a specific location.
Rock that results from the consolidation of layers of loose sediment made up of various kinds of organic and inorganic matter.
The process in which solid suspended particulates settle out of a liquid (water). Usually the water or liquid is subjected to little or no movement. The process may be accelerated by feeding a coagulant such as alum. Also referred to as "settling".
The percolation of water through the soil from unlined channels, ditches, water courses, and water storage facilities.
Seize up occurs when an engine overheats and a part expands to the point where the engine will not run.
Also called "freezing."
The tendency of an ion exchanger to "prefer" (have more attraction for) certain kinds of ions over others, as if the resin were ranking the types of ions in order to be removed: most preferred ion, second most preferred, etc.
The respective region or zone within an ion exchanger or adsorption medium bed where individual ions or substances accumulate and are removed from the water in order of their individual respective preferences for the medium.
Because different substances each have different affinities or selectivity preference for the treatment medium, removal occurs in different zones of the medium bed.
The zone for the ion or substance with the lowest selectivity will proceed through the bed first, and the zone for the highest selectivity substance will proceed through the bed last.
See Also: Selective Ion Exchanger
Semiconductor Equipment and Materials International.
The group which has set the electronics grade purified water standards.
An aquifer that is partially confined by a soil layer (or layers) of low permeability through which recharge and discharge can occur.
Usually a thin, organic film which will allow the passage of some ions or materials while preventing the passage of others. Some membranes will only allow the passage of anions; other will allow the passage of cations. Some membranes reject most dissolved susbstances but allow the passage of water.
An electrical or electronic device which measures the quality of the product water leaving the treatment cycle.
A sensing meter which measures conductivity or resistivity (resulting from TDS) is used for deionization, electrodialysis and reverse osmosis.
In a cation water softener, sensors used are either as:
1. electronic devices which measure hardness in effluent softened water, or 2. probes which detect the slightly different electrical impedance between that caused by calcium/magnesium and sodium ions. The sensor is immersed in the resin bed and triggers regeneration.
See Also: Monitoring Light Sensor
A spiral-wound membrane element or cartridge used in cross flow membrane systems.
A diseased state caused by the presence of pathogenic microorganisms in the bloodstream.
The liquid and semisolid contents removed by pumping from a septic tank.
A condition produced by bacteria when all oxygen supplies are depleted. If severe, bottom deposits appear and water turns black, gives off foul odors, and the water has a greatly increased chlorine demand.
An on-site system designed to treat and dispose of domestic sewage; a typical septic system consists of a tank that receives wastes from a residence or business and a system of tile lines or a pit for disposal of the liquid effluent that remains after decomposition of the solids by bacteria in the tank.
See Also: Antiseptic Aseptic Aseptic Procedure Sterilize Sterilization Septic Tank Dry-Salt Saturator Tank Wet-Salt Saturator Tank Service Unit
A tank (usually underground) into which the solid matter of household sewage flows and is held for decomposition caused by bacteria.
Septic tanks are common in rural areas where no municipal sewage system is available.
See Also: Antiseptic Aseptic Aseptic Procedure Sterilize Sterilization Septic System Community Water System Municipal Water
Bacteria multiplying in the bloodstream.
One action occurring after or followed by others in a given order--as opposed to simultaneous actions.
A chemical reaction in which certain ions are bound into a stable, water soluble compound, thus preventing undesirable action by the ions.
A chemical compound sometimes fed into water to tie up undesirable ions, keep them in solution, and eliminate or reduce the normal effects of the ions. For example, polyphosphates can sequester hardness and prevent reactions with soap.
A chemical reaction in which certain ions are bound into a stable water-soluble compound so that they (ions) are prevented from certain normal but undesirable actions.
For example, the sequestration of iron to prevent it from oxidizing, precipitating, and staining.
See Also: Chelating Agent Sequestering Agent Chelating agent
The arrangement of two or more filtering steps, one following the other, in order to remove increasingly finer particulates at each stage and provide for filtration of all sizes of suspended solids.
Cartridge-style units often employ this method, using depth prefilters (compressed fibers) followed by surface filtration with a micromembrane cartridge element.
The rate in U.S. gallons per minute (gpm) or liters per minute (L/min) at which a given water processing system can deliver product water. The rating may be for intermittent peak flow or constant flow.
A one-liter sample of water collected in accordance with CFR Section 141.86(b)(3) of the code of Federal Regulations, that has been standing for at least six hours in a service line.
The pipeline extending from the water main to the building served or to the consumer's system.
That portion of the operating cycle of a water conditioning unit in which treated water is being delivered, as opposed to the period when the unit is being backwashed, recharged, or regenerated.
A term sometimes applied to softeners or filters which are regenerated or backwashed at a central point and transported to the point of use for connection to the water system. Also known as portable exchange units.
Attached firmly to a permanent base and not free to move about.
Bacteria grow and multiply faster when attached (sessile) in water systems, than when free-floating (planktonic) in water. Attached sessile cells form a larger colony; their polysaccharide containing glycocalyx slime layer helps adhere other bacteria cells and nutrients which float past and also acts as a protective layer which resists chemical disinfectant penetration.
This sessile microbial colonization is known as biofilm in water systems.
The position at which the control or controller is set.
This is the same as the desired value of the process variable.
The combination of liquids or water carrying wastes from homes, businesses, institutions, and industries.
In some cases, storm water, groundwater, and surface water may be included in the sewage flow. In the larger sense, sewage is the water supply of a community after the water supply has been used.
See Also: 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 Aesthetic Contaminants 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 Silica Sodium Carbonate Softened Water Soft Water
An underground system of conduits (pipes and/or tunnels) that collect and transport waste waters and/or runoff; gravity sewers carry free-flowing water and wastes; pressurized sewers carry pumped waste waters under pressure.
The network of sewers that carries sewage from point of origin to point of treatment.
A well sunk in easily-penetrated ground to a point which is below the water table but usually less than about 30 feet in depth.
The action of low temperature water flowing at high rates which splits and separates particle agglomerations, and prevents the formation of floc deposits during the coagulant feed/filtration process.
This action may also tear away from the filter any previous deposits or suspended matter.
The separation and insulation of metal parts of a pipe joint by a special fitting which will not conduct electric current.
The fitting prevents corrosion caused by galvanic action between two different metals.
Shielding can also be a protective cover or barrier that prevents transmittance of heat or radiation to or from a component of water treatment equipment.
The arrival at a water treatment system of raw water containing unusual amounts of algae, colloidal matter, color, suspended solids, turbidity, or other pollutants.
A condition that occurs in tanks or basins when some of the water travels faster than the rest of the flowing water.
This is usually undesirable since it may result in shorter contact, reaction, or settling times in comparison with the theoretical (calculated) or presumed detention times.
The International System (SI) of units that was adopted and recommended for use in science and technology by the 11th General Conferece on Weights and Measures in 1960.
This coherent system of units is built from the following seven SI base units:
Physical Name of SI Unit Symbol for Quantity SI Unit
length meter m
mass kilogram kg
time second s
electric ampere A current
thermodynamic kelvin K temperature
amount of mole mol substance
luninous candela cd intensity
Formerly called mho.
The siemens (S) is the SI unit of conductance equal to the reciprocal of the ohm.
The SI unit of ionizing radiation dose equivalent.
One sievert (Sv) equals 100 rems.
As used in water chemistry, a collective term encompassing dissolved, undissolved, and colloidal silica. Silica is present in almost all minerals and is found in fresh water in a range of 1 to 100 mg/L.
In undissolved form, silica exists as minute particulate and as encapsulated silica as small as 0.02 micron colloids and polymers. In dissolved form, it can appear as a silicate, silicon dioxide (SiO2), and as silicic acid (H2SiO3).
Usually expressed as SiO2 mg/L in water analysis.
Silica concentrations above 120 mg/L in reverse osmosis waste streams (concentrate water) may cause silica deposition which is difficult to remove from the membrane.
See Also: 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 Aesthetic Contaminants 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 Sodium Carbonate Softened Water Soft Water Etching
A synthetic hydrated sodium alumino silicate with ion exchange properties once widely used in ion exchange water softeners.
Soil particles between 0.05 and 0.002 millimeter in approximate diameter.
A test used to measure the level of suspended solids in feedwater for membrane filtration systems.
The test consists of the time it takes to filter 500 milliliters of the test water through a 47 millimeter diameter, 0.45 micron rated microporous filter under a constant pressure of 30 psig.
The SDI of feedwater to a reverse osmosis membrane should be maintained at less than 5, preferably less than 3.3.
SDI = 100 (1-t1/t2)/T
t1 = time to filter 500 mL of water initially,
t2 = time to filter 500 mL of water after T minutes (T is usually 15 minutes.)
To reproduce the action of some process, usually on a smaller scale.
A building constructed as a single-family residence that is currently used as either a residence or a place of business.
A pump that has only one impeller. A multistage pump has more than one impeller.
(reverse osmosis) Process used in a multiple (2-6) membrane reverse osmosis system in which a portion of the concentrate stream is split off and routed back to the inlet and mixed with the feedwater.
This increases the flow across the membrane without increasing the amount of feedwater and increases the overall recovery rate. The pump capacity will affect the amount of water to be recirculated and the recovery rate.
(reverse osmosis) A reverse osmosis system in which the water is passed through the membrane(s) only once by using a single high-pressure pump.
A place in the environment where a compound or material collects.
To react calcium oxide (lime or quicklime) with water to form calcium hydroxide (slaked or hydrated lime) plus heat.
See Also: Lime (CaO) Lime Softening Burnt Lime (CaO) Hydrated Lime Hot-Lime Softening Hot Lime-Soda Softening Hot Process Softening Municipal Softening Quicklime Water Softening Salinometer Soap Soda Ash Soap Curd
The slope or inclination of a trench bottom or a trench side wall is the ratio of the vertical distance to the horizontal distance or "rise over run."
See Also: Hydraulic Grade Line Energy Grade Line (EGL) United States Pharmacopeia (USP) WFI
Underdrain lateral pipes which have many tiny openings (as though they had been partially cut around the perimeter with a hacksaw) instead of orifices (drilled 1/4 in. or 3/16 in. holes.)
The action of a medium (filter, ion exchanger, or membrane) casting off into the effluent stream any substance intended for removal from the water.
Sloughing may be caused by shearing action or by ion selectivity.
A process involving passage of raw water through a bed of sand at low velocity (generally less than 0.4 m/h) resulting in substantial particulate removal by physical and biological mechanisms.
The semi-fluid solid matter collected at the bottom of a system tank or watercourse as a result of the sedimentation or settling of suspended solids or precipitates.
An abnormally high concentration of an undesirable substance which passes through a water system. Usually brief or intermittent in nature, and often related to an upset of a system. For example, a slug of iron may occur during high flow which disturbs and suspends previously deposited iron precipitates.
A watery mixture or suspension of insoluble (not dissolved) matter; a thin watery mud or any substance resembling it (such as a grit slurry or a lime slurry).
Copper or stainless steel pipe with a small diameter of 0.5 inches or 15 mm.
Such pipe is commonly found in pump-assisted hot water central heating systems.
Secondary Maximum Contaminant Levels. Secondary MCLs for various water quality indicators are established to protect public welfare.
Suggested No Adverse Response Level. The concentration of a chemical in water that is expected not to cause an adverse health effect.
One of a class of chemical compounds which posesses cleaning properties formed by the reaction of a fatty acid with a base or alkali. Sodium and potassium soaps are soluble and useful, but can be converted to insoluble calcium and magnesium soaps (curd) by the presence of these hardness ions in water.
The insoluble precipitate that forms when soap is used in hard water. Soap curd and lime soap are synonymous
See Also: Lime (CaO) Lime Softening Burnt Lime (CaO) Hydrated Lime Hot-Lime Softening Hot Lime-Soda Softening Hot Process Softening Municipal Softening Quicklime Water Softening Salinometer Slake Soap Soda Ash Lime Soap Soap Carbonate Hardness Bicarbonate Hardness Lime Soap Hardness Hard Water Total Hardness (TH)
synthetic organic chemicals.
(Na2CO3) A common water treatment chemical, sodium carbonate, which is used for pH modification, as an alkaline builder in some soaps and detergents, and in the lime-soda ash water softening process.
See Also: Lime Softening Hot Lime-Soda Softening Hot Process Softening Municipal Softening Lime Softening Hot Lime-Soda Softening Detergent Municipal Softening Water Softening Sodium Carbonate Lime (CaO) Lime Softening Burnt Lime (CaO) Ion Exchange Hydrated Lime Hot-Lime Softening Hot Lime-Soda Softening Hot Process Softening Municipal Softening Rated Capacity Water Softening Rated Capacity Hexametaphosphate Calcite Carbonate Hardness Bicarbonate Hardness Hardness Hardness as Calcium Carbonate Plastic Pipe Calcium Carbonate Total Hardness (TH)
Water which has been impregnated with carbon dioxide (CO2) so that it will be effervescent when not under pressure. Same as carbonated water, seltzer water, and sparkling water.
See Also: Lime Softening Club Soda Hot Lime-Soda Softening Hot Process Softening Municipal Softening Water Softening Soda Ash Sodium Carbonate
(Na+) A metallic element found abundantly in compounds in nature, but never existing alone.
Sodium compounds are highly soluble and do not form curds when used with soaps or detergents.
Many sodium compounds are used in the water treatment industry. Most notable is the use of sodium chloride as a regenerant in the cation exchange water softening process.
(NaHCO3) A mild alkali, commonly called baking soda.
Sodium bicarbonate is used in powdered hard surface cleaners and some presoak formulations to provide alkaline cleaning at a controlled level.
(Na2CO3) A fairly strong alkaline salt occurring naturally as soda ash.
A solution of sodium carbonate (soda ash) may be used with a simple proportionate chemical feed pump system to raise the pH of a water supply. Each mg/L of carbon dioxide in water requires a minimum of 2.5 mg/L of soda ash for neutralization.
Sodium carbonate finds wide use as a builder in laundry detergents and as a source of alkalinity in powdered hard surface cleaners and presoak products. Sodium carbonate supplies alkaline cleaning power and also softens water by precipitating the hardness minerals out of solution.
It is also called soda ash and is available on the retail market in a hydrated crystalline form under the name "washing soda."
See Also: Detergent Phosphate Backflow Chromatography Cross Connection Liquid Chromatography Gas Chromatograph (GC) Gas Chromatography (GC) Organic Turbidity Jackson Turbidity Unit (JTU) High Performance Liquid Chromatography (HPLC) Mass Spectrometry (MS) Alkalinity Aromatic Autotrophic Hydrogen Ion Concentration Heterocyclic Heterotrophic Heterotrophic Microorganisms Hexametaphosphate Nephelometer Nephelometric Nephelometric Turbidity Unit (NTU) Vacuum Breaker United States Pharmacopeia (USP) WFI Sodium Hexametaphosphate Sodium Metaphosphate Lime Softening Club Soda Hot Lime-Soda Softening Hot Process Softening Municipal Softening Water Softening Soda Ash Soda Water Lime Softening Hot Lime-Soda Softening Detergent Municipal Softening Water Softening Soda Ash 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 Aesthetic Contaminants 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 Softened Water Soft Water Lime Soap Permutit Process Phosphate Water Softening
The chemical name for common table salt.
Sodium chloride is also widely used for regeneration of ion exchange water softeners and in some dealkalizer systems.
See Also: Salt Common Salt Brackish Water Brine Dry-Salt Saturator Tank Wet-Salt Saturator Tank Salt
The sodium salt of citric acid.
Sodium citrate sequesters hardness minerals and is used as a builder in some nonphosphate products. Its principal application is in liquid laundry detergents; it also is used in some presoak products.
The cation exchange water softening process in which sodium ions in the resin are exchanged for hardness ions in the water.
Sodium chloride is commonly used for resin regeneration.
(Na2S2O4) A crystalline salt which is a strong reducing agent and the main ingredient in several resin cleansers that are used to clean iron-fouled ion exchange resin beds.
A strong alkaline compound used as a regenerant for anion exchange resin in deionization systems and for the pH modification of low pH (acid) water.
Sodium hydroxide is also called caustic, caustic soda, or lye.
Liquid bleach; used as a source of chlorine in water treatment.
Laundry bleach available from grocery stores is 5.25 percent chlorine and commercial strength bleach available from swimming pool suppliers or chemical companies is usually 12.5 percent chlorine.
Any of several complex phosphates with excellent sequestering properties.
See Also: Hexametaphosphate Sodium Hexametaphosphate
(Na2SiO2 or SiO2,Na2) Glassy polymeric silicates used to prevent corrosion by formation of a thin passivating film on metal surfaces in boilers and other water systems.
(Na5P3O10) A crystalline salt used chiefly as a water softener, sequestering agent, and deflocculating agent, especially in soaps and detergents.
Any water which contains less than 1.0 gpg (17.1 mg/L) of hardness minerals expressed as calcium carbonate.
Any water that is treated to reduce hardness minerals to 1.0 gpg (17.1 mg/L) or less, expressed as calcium carbonate.
Computer programs; the list of instructions that tell a computer how to perform a given task or tasks.
A measure of the soil's susceptibility to raindrop impact, runoff, and other erosional processes.
A vertical section of the earth's highly weathered upper surface often showing several distinct layers or horizons.
The arrangement of soil particles into aggregates.
The proportions of soil particles (sand, silt, and clay) in a soil profile.
Common salt which is produced by solar evaporation in shallow ponds or lagoons and used in water softener regeneration.
A metallic compound used to seal the joints between pipes.
Until recently, most solder contained 50 percent lead. The use of lead solder containing more than 0.2 percent lead is now prohibited for pipes carrying potable water.
An aquifer that supplies 50 percent or more of the drinking water of an area.
A magnetically (electrical coil) operated mechanical device.
Solenoids can operate a small valve or a switch.
An electrical device operated by a magnetic coil to make the valve either open for flow or close to shut off water flow.
This type of valve is used extensively for flow control and direction on many water processing systems.
(In water and waste water laboratory analyses) The matter dissolved or suspended in water or waste water.
The substance which is dissolved in a solvent. Dissolved solids, such as the minerals found in water, are solutes.
A mixture in which one or more substances (solutes) are dissolved into another substance (solvent), usually a liquid, in such a way that the solute is equally distributed (homogeneous) throughout the solvent in the form of either molecules (as in a sugar solution) or ions (as in a salt solution).
A mechanical device, such as a power driven pump or an eductor system, designed to feed a solution of a water treatment chemical into the water system usually in proportion to flow.
The liquid, such as water, in which other materials (solutes) are dissolved.
The concentration of dissolved solids on the surface (absorption) of suspended solids or solids contained in a fixed bed.
A pipe or tube used for measuring the depths of water.
Brine that contains a high concentration of calcium, magnesium, or other substances that would interfere with its use or reuse for effective regeneration of exhausted ion exchange resin.
The scale or range of values an instrument is designed to measure.
See Also: Effective Range Range
A perforated pipe in an aerator or ozone contact compartment through which the air or ozone-containing air is sprayed into the water, and which allows for the diffusion of the air or ozone into the water.
A rapid method of estimating the total dissolved solids (TDS) content of a water supply.
Its measurement indicates the capacity of a sample of water to transmit an electrical current, which is associated with the concentration of ionized substances in the water. An alternate method is the measurement of specific (electrical) resistance.
The unit of measure for specific conductance is siemens (formerly called mhos) per centimeter which is 1.0 divided by specific resistance. When the numbers get too small, the microsiemens ( S) is used.
For example, 100 mg/L of NaCl dissolved in water causes a specific conductance of 212 microsiemens per centimeter, whereas a 1,000 mg/L solution of NaCl in water would result in 2,000 microsiemens per centimeter.
It is well known that pure water is a very poor conductor of an electric current. However, when ionizable compounds (salts, etc.) are dissolved in the water, the solution becomes a conductor of electric current. The nature of the ionized compound and the amount of it dissolved are responsible for the specific conductance (or specific resistance) of the solution.
The more salts dissolved, the greater is the specific conductance.
See Also: Conductivity Electrical Conductivity Specific Resistance Conductance Conductivity Electrical Conductivity Specific Resistance Conductance Conductivity Electrical Conductivity Specific Resistance Specific Resistance
The ratio of the weight of a specific volume of a substance compared to the weight of the same volume of pure water at 4oc
The capacity for resisting the flow of electrical current.
In the case of liquids, such as water, specific resistance is the resistance of a 1.0 centimeter cube, which is the resistance offered by the liquid between two electrode plates 1 cm. square and placed 1 cm. apart.
The unit of measure is ohms-centimeter, and specific resistance is the reciprocal of specific conductance.
One hundred milligrams per liter of NaCl dissolved in water causes a specific resistance of 4,716 ohms-centimeter, whereas a 1,000 mg/L solution of NaCl in water would result in 500 ohms-cm.
See Also: Specific Conductance Conductivity Electrical Conductivity Specific Conductance Specific Conductance Conductance Conductivity Electrical Conductivity Specific Conductance
The quanity of water that a unit volume of saturated permeable rock or siol will yield may be expressed as a ratio or as a percentage by volume
A chemical analytical instrument used in spectroscopy.
See Also: Atomic Absorption Spectroscopy AAMI Grade Water Induced Infiltration Spectroscopy Emission Spectroscopy
A technique used in chemical analyses which is based on the principle that many substances, when crossed by a beam of light, allow a unique and well-defined fraction of that light to pass or emit a well-defined fraction of radiation when returning from an atomic vapor state to their fundamental state.
The characteristic wave length pattern of the absorbed or emitted light can be used to identify the particular substance with great certainty.
The quantity of the light absorbed or emitted is proportional to the concentration of the substance.
Spectroscopy is one of the most frequently used analytical methods for water analyses. Ultraviolet light (UV) spectroscopy (using light wave lengths between 10 and 390 nanometers) and infrared (IR) spectroscopy (using light wave lengths between 780 and 300,000 nanometers) are used particularly to identify and quantify organic molecules. Atomic absorption spectroscopy (AA) is used to identify and quantify inorganic elements.
Spectroscopy is also called spectrometry and spectrophotometry.
See Also: Atomic Absorption Spectroscopy Induced Infiltration Emission Spectroscopy Atomic Absorption Spectroscopy Induced Infiltration Adsorption Emission Spectroscopy Atomic Absorption Spectroscopy AAMI Grade Water Spectrometer Induced Infiltration Emission Spectroscopy Atomic Absorption Spectroscopy Fahrenheit Induced Infiltration Atomic Absorption Spectroscopy AAMI Grade Water Spectrometer Induced Infiltration Emission Spectroscopy
The measure of the bead roundness or "whole bead" count of beads in an ion exchange resin product or other bead form absorbent or filter medium.
A very common construction configuration for one style of reverse osmosis membrane and cartridge filter element.
In RO membranes, the membrane sheets are assembled in layers around a perforated mandrel product water tube, with coarse mesh spacer screens between the layers, to form a complete module element.
In cartridge filter elements, the filtration material, such as fiber cord, is continuously wound around a perforated mandrel core tube.
The art of proportionally blending a stream of treated water with a stream of untreated water from the same source to achieve a lower measurement of a given contaminant in the blended stream, thus not removing all of the contaminant but still meeting the water quality desired, such as meeting a maximum contaminant level requirement for delivered water.
Split-stream operation makes it possible to treat less than the full flow of water.
Excavated material such as soil from the trench of a water main.
In general, the reproductive body of an organism capable of reproducing the organism under favorable conditions. In water, most spores resist adverse conditions which would readily destroy the parent organism. The spore is sometimes considered the resting state of the organism.
An agent that destroys microbial spores. By definition, sterilizing agent.
See Also: Microbiocide Sterilize Biocide Antiseptic Aseptic Aseptic Procedure Disinfect Sanitization Sanitize
A place where groundwater flows naturally from the soil or rock formation onto the land surface or into a body of surface water.
A spring is sometimes used as a source of water for a shallow dug well.
Theoretical center of a pipeline. Also, the guideline for laying a course of bricks.
Water obtained from an underground formation from which water flows naturally to the surface, or would flow naturally to the surface if it were not collected underground.
The ability of an ion exchange product or filter medium to withstand physical and chemical degradation in cycle-after-cycle operations.
A chromium alloy with substantially 50 percent or more iron and usually with some nickel (typically 12 to 30 percent chromium and zero to 22 percent nickel) that is practically inert toward rusting and corrosion.
The nickel content of ss contributes to improved corrosion resistance. Austenitic stainless steel contains 16 to 26 percent chromium, six to 22 percent nickel, low (less than 0.15 percent) carbon, and cannot be hardend by heat treatment; ferritic ss contains 15 to 30 percent chromium, low (0.1 percent) carbon, and cannot be hardened by heat treatment; martensitic ss contains 12 to 20 percent chromium, controlled carbon and other additives, and can be hardened by heat treatment which increases the tensile strength from 80,000 to 200,000 psi.
A physical or chemical quantity whose value is known exactly and is used to calibrate or standardize instruments.
The statistical classification standard published by the United States Office of Management and Budget (OMB) that assigns an industry number to businesses and business units by type of economic activity.
It is the classification standard underlying all establishment-based Federal economic statistics classified by industry type.
The system uses from a one-digit to a four-digit classification number depending on how narrowly the business unit is defined. There are 11 one-digit groupings and over 1,000 four-digit groupings.
Household and industrial water treatment equipment manufacturing, for example, is in SIC 3589, water conditioning service is in SIC 7389, distribution of water conditioning equipment is in SIC 5074, manufacturing of fluid power control valves is in SIC 3492, manufacturing of water treatment chemicals is in SIC 2899, manufacturing of distilled water is also in SIC 2899, manufacturing of pharmaceutical water or of water purification tablets is in SIC 2834, manufacturing of carbonated and flavored bottled water is in SIC 2086, bottling natural, spring, or mineral water is in SIC 5149, and retailing bottled water is in SIC 5499.
The abbreviation for the name of the reference book "Standard Methods for the Examination of Water and Wastewater", widely used in water and wastewater testing and analysis.
A joint publication of the American Public Health association, American Water Works Association and the Water Pollution Contol Federation which outlines the procedures used to analyze the impurities in water and waste water.
The aliquot of finished drinking water that is examined for the presence of coliform bacteria.
A solution in which the exact concentration of a chemical or compound is known.
To compare with a standard.
In chemistry, to find out the exact strength of a solution by comparing it with a standard of known strength, or to set up an instrument or device to read a standard. This allows you to adjust the instrument so that it reads accurately, or enables you to apply a correction factor to the readings.
Chemically, starch refers to complex carbohydrates obtained from vegetable sources.
In home laundry usage, the term has been expanded to cover products that perform the same function as starch, i.e., supplying body or stiffness to fabrics, but that are based on synthesized chemicals such as carboxymethylcellulose or polyvinyl acetate. The latter are called synthetic or plastic starches.
Vegetable starch comes as:
dry, uncooked starch (lump, cube, or powder), which must be mixed with hot water or cooked before use; pre-cooked flakes, which can be mixed with cold water; a concentrated pre-cooked solution; and a concentrated solution in an aerosol container for spraying directly on fabrics while ironing. Synthetic or plastic starches come as liquids and in aerosol form for direct application. The liquids are available in soluble form, which is removed in the next laundering. More durable varieties last through several washes.
Besides supplying body and stiffness, starch gives ironed articles a fresh smooth appearance, helps garments stay clean longer because of the harder, smoother surface, and facilitates soil removal in the next wash since the soil becomes imbedded in the starch, not the fabric.
Devices used to start up large motors gradually to avoid severe mechanical shock to a driven machine and to prevent disturbance to the electrical lines (causing dimming and flickering of lights).
The agency of the State or Tribal government which has jurisdiction over public water systems.
During any period when a State or Tribal government does not have primary enforcement responsibility pursuant to Section 1413 of the Safe Drinking Water Act, the term "State" means the Regional Administrator, U.S. Environmental Protection Agency.
Fixed in position, resting, or without motion, as opposed to dynamic or moving.
When water is not moving, the vertical distance (in feet) from a specific point to the water surface is the static head.
(The static pressure in psi is the static head in feet times 0.433 psi/ft.)
See Also: Static Pressure Osmosis Head Loss Delta P Static Pressure Biostat Static Pressure Osmosis Head Loss Delta P Static Pressure
The static pressure in psi is the static head in feet times 0.433 psi/ft.
The static pressure in psi is the static head in feet times 0.433 psi/ft.
See Also: Static Head Osmosis Head Loss Delta P Static Head Biostat Static Head Pressure Drop Friction Losses
A system or process in which the reactants are not flowing or moving.
The vertical distance in feet from the center line of the pump discharge down to the surface level of the free pool while no water is being drawn from the pool or water table.
The elevation or level of the water table in a well when the pump is not operating. The level or elevation to which water would rise in a tube connected to an artesian aquifer, or basin, or conduit under pressure.
That portion of a machine which contains the stationary (non-moving) parts that surround the moving parts (rotor).
The flow in U.S. gallons per minute (or liters per minute) at which a water processing filter or ion exchanger will deliver its rated capacity.
For water softeners, this flow is based upon delivering softened water from an incoming raw water of 20 grains per gallon total hardness as calcium carbonate.
The method of regenerating ion exchange resin beds several times with the same regenerant, but at a higher concentration each time.
The method is usually used to avoid calcium sulfate precipitation when sulfuric acid is employed as a regenerant for cation bed units of deionizer systems that are being used to decationize unsoftened feedwater.
A process in which all living organisms are destroyed and residual removed from liquid.
An instrument used to magnify sounds and convey them to the ear.
Based on the assumption that the actions of a chemical substance results from probabilistic events.
Related to the proportions in which chemicals combine to form compounds and the weight relations in chemical reactions.
Stoichiometry is the mathematical and theoretical study of how chemicals combine.
A formula for calculating the rate of fall of particles through a liquid medium.
The rate at which a spherical particle will rise or fall when suspended in a liquid medium varies as the square of the particle's radius, as the density of the particle, and as the viscosity of the fluid.
The maximum volume of water available for use from the water storage tank, e.g., the amount available from a RO or distiller water storage tank.
A compartment used to accumulate the product water from a water treatment unit so sufficient quantity and/or pressure is available for intermittent periods of higher flow rate water use.
A sewer that collects and transports surface runoff to a discharge point (infiltration basin, receiving stream, treatment plant).
The formation of separate layers (of temperature, plant, or animal life) in a lake or reservoir.
Each layer has similar characteristics such as all water in the layer has the same temperature.
See Also: Hydraulic Classification Thermal Stratification
In ion exchange applications, a bed in which two exchangers of different classes and different densities have been placed in the same column (bed), such as weak base anion resin on top of a strong base anion exchanger, or in cation exchange systems, a weak acid on top of a strong acid resin.
See Also: Energy Grade Line (EGL) Hydraulic Classification
A cartridge-style filter element constructed by continuous spiral winding of natural or synthetic yarn around a preformed product water tube core and then building it up in layers to form a depth-type filter element.
A crop production system that involves planting alternating strips of row crops and close-growing forage crops; the forage strips intercept and slow runoff from the less protected row crop strips.
A cation exchange resin with an exchange site/active group (usually sulfonic) capable of splitting neutral salts (NaCl, MgSO4, Ca[NO3]2, etc.) to form their corresponding free acids (HCl, H2SO4, HNO3, etc.).
See Also: Chelation Chelating Agent Organic Iron Humic Substances Free Acid Form Weak Acid Cation Exchangers Total Acidity
An anion exchange resin with an exchange site/active group [usually quaternary amine, -N(CH3)+++] capable of splitting neutral salts (NaCl, CaSO4, KNO3, etc.) to form their corresponding free bases (NaOH, Ca[OH]2, KOH, etc.).
(C8H8) A fragrant, liquid, unsaturated hydrocarbon used chiefly in the manufacture of synthetic rubber, resins, and plastics.
Styrene is the prime ingredient in many cation and anion exchange resins.
Of intermediate duration, usually used to describe studies or levels of exposure between five and 90 days.
Aquatic vegetation, such as sea grasses, that cannot withstand excessive drying and therefore live with their leaves at or below the water surface.
SAVs provide an important habitat for young fish and other aquatic organisms.
The distance between the water surface and the media surface in a filter.
A pump designed to fit inside the well casing and to operate below the water level in a drilled well.
A cartridge-type membrane filter used in fine particle separation applications to remove particulates of less than one micron in size.
The negative pressure [in feet (meters) of water or inches (centimeters) of mercury vacuum] on the suction side of the pump.
The pressure can be measured from the center line of the pump down to (lift) the elevation of the hydraulic grade line on the suction side of the pump.
Sulfate-reducing bacteria, such as Desulfovibrio, and the single-celled aerobic sulfur-oxidizers of the genus Thiobacillus.
The sulfate-reducing bacteria contribute to tuberculations and galvanic corrosion of water pipes and to hydrogen sulfide taste and odor problems in water. Thiobacillus, by its production of sulfuric acid, has contributed to acid corrosion of metals.
(-SO2OH) A specific acidic group which forms the exchange site active group in certain cation exchange resins and gives these resins their ion exchange capability.
A yellowish, solid element (S). The term is also used as a slang expression to refer to water containing hydrogen sulfide gas.
Water containing objectionable amounts of hydrogen sulfide gas which causes an offensive "rotten egg" odor.
The addition of excess amounts of chlorine to a water supply to speed chemical reactions or insure disinfection with short contact time. The chlorine residual following superchlorination is high enough to be unpalatable, and thus dechlorination is commonly employed before the water is used.
Federal law which authorizes USEPA to manage the cleanup of abandoned or uncontrolled hazardous waste sites.
The clear liquid lying above a sediment or precipitate.
An unstable condition of a solution (water) in which the solution contains a substance at a concentration greater than the saturation concentration for the substance.
Any person who owns or operates a public water system.
Material of a specific graded particle size (such as gravel) used as a subfill to support the primary medium bed.
In larger diameter systems (tanks), this bed improves the collection of processed water and promotes more uniform distribution of the backwashing water.
Filtration that occurs at the surface layer (as opposed to within the body depth) of the filter and is accomplished by passing the material to be filtered over a grating, screen, sieve, or membrane fabric with microsized holes.
The size of the holes in the filter determines what materials will pass through and what will be filtered out (held back).
One of the guidelines for the design of settling tanks and clarifiers in treatment plants.
Used by operators to determine if tanks and clarifiers are hydraulically (flow) over- or underloaded.
Also called overflow rate.
A mechanism for removing water or waste water from a sump or wet well.
Precipitation, snow melt, or irrigation in excess of what can infiltrate the soil surface and be stored in small surface depressions; runoff is a major transporter of nonpoint source pollutants.
The result of attraction between molecules of a liquid which causes the surface of the liquid to act as a thin elastic film under tension. Surface tension causes water to form spherical drops and to reduce penetration into fabrics. Soaps, detergents, and wetting agents reduce surface tension and increase penetration by water.
All water naturally open to the atmosphere (rivers, lakes, reservoirs, streams, impoundments, seas, estuaries, etc.) and all springs, wells, or other collectors which are directly influenced by surface water.
A contraction of the term "surface-active agent"
A chamber or tank connected to a pipe and located at or near a valve that may quickly open or close or a pump that may suddenly start or stop.
When the flow of water in a pipe starts or stops quickly, the surge chamber allows water to flow into or out of the pipe and minimize any sudden positive or negative pressure waves or surges in the pipe.
Solid particles in water which are not in solution.
Brine that contains sufficient sodium or potassium content and is relatively low in calcium, magnesium, or other interfering substances such that it is effective for use or reuse in regenerating exhausted ion exchange resin.
See Also: Reclaimed Brine
Fresh water. Palatable water. Not salt water.
The expansion of certain ion exchange resins when converted into a specific ionic state.
This is a reversible expansion, as the resin may well shrink as it becomes exhausted. Some exchangers will expand as they exhaust.
Cation exchange water softening resins will generally swell when exhausted (loaded with hardness ions) and will shrink when regenerated with heavier salt dosages of 10 to 15 pounds of sodium chloride (NaCl) or potassium chloride (KCl) per cubic foot of resin.
Standard cation softening resin (8 percent polystyrene/DVB), in the calcium form, will shrink about 5 percent in volume when treated with a 25 percent salt-brine solution.
The combined action of several chemicals which produces a greater effect than would be obtained by simply adding together the effects produced by each chemical separately.
Synergism is also called synergy.
A manufactured cleaning agent.
Detergents can be classified as anionic, cationic, or nonionic.
Man-made organic substances including herbicides, pesticides, and various industrial chemicals and solvents.
Synthetic organic chemicals are generally considered dangerous in drinking water at concentrations above the USEPA maximum contaminant levels.
Often referred to as SOCs.
A complete integrated series consisting of various components and perhaps multiple water treatment processes which can be tested, installed, and operated as a singular unit of equipment.
For example, a single RO treatment system generally consists of two or more stages of media filtration plus cross flow membrane filtration and water storage.
A public water system which supplies drinking water to consumers via a single service line.
Relating to whole body, rather than its individual parts.
Effects observed at sites distant from the entry point of a chemical due to its absorption and distribution into the body.