Glossary of Terms - C
A B C D E F G H I J K L M N O P Q R S T U V W Z
calcite - 1. Calcium carbonate (CaCO3). 2. A trade name for finely ground grades of marble or limestone, very high in calcium carbonate, which are used to raise the pH reading (reduce the acidity) of low pH (acidic) water or to filter out sediment.
calcium (Ca) - One of the principal elements in the earth's crust. When dissolved, in water, calcium compounds make water hard. The presence of calcium in water is a factor contributing to the formation of scale and insoluble soap curds which are a means of clearly identifying hard water.
calcium carbonate (CaCO3) - A chemical compound found in nature as calcite (in limestone, marble, and chalk) and aragonite (in pearls) and in plant ashes, bones and many shells.
calcium carbonate equivalent - A common basis for expressing the concentration of hardness and other salts in chemically equivalent terms to simplify certain calculations; signifies that the concentration of a dissolved mineral is chemically equivalent to the stated concentration of calcium carbonate.
calcium hypochlorite [Ca(OCl)2] - A chemical compound, used as a bleach and as a source of chlorine in water treatment. Commercial grades contain 70 percent available chlorine. It is specifically useful because it is stable as a dry powder and can be formed into pellets.
capacity - An expression of the quantity of an undesirable material which can be removed from water by a water conditioning medium, i.e., cleaning, regeneration or replacement, as determined under standard test conditions. For ion exchange water softeners, the capacity is expressed in grains of hardness removed between successive regenerations and is related to the pounds of salt used in regeneration. For filters, the capacity may be expressed in the length of time or total gallons delivered between servicing.
capacity curve (ion exchange) - A graph of the ion exchange capacity versus regenerant levels for an ion exchange unit or system.
capillary action - A phenomenon in which water or many other liquids will rise above the normal liquid level in a tiny tube or capillary, due to attraction between molecules of the liquid for each other and the walls of the tube.
carbonaceous - Materials of or derived from organic substances such as coal, coconut shells, wood, etc.
carbonaceous exchanger - Cation ion exchangers of limited capacity, prepared by the sulfonation of coal, lignite, or peat. Often contain both strong and weak acid groups.
carbonate - The CO32- ion.
carbonate alkalinity - Alkalinity due to the presence of the carbonate ion (CO32-).
carbonate hardness - That hardness in water caused by bicarbonates and carbonates of calcium and magnesium. Carbonate hardness is also called temporary hardness because it can be precipitated by boiling.
carbon chloroform extract (CCE) - A measure of the organic matter in a water. To get this measurement, the matter adsorbed from water by activated carbon is extracted from carbon with chloroform, using a specific standardized procedure.
carbon dioxide (CO2) - A gas present in the atmosphere and formed by the decay of organic matter; the gas in carbonated beverages; in water it forms carbonic acid (H2CO3).
carboxylic - An organic acidic group which contributes cation exchange ability to some resins.
carcinogen - Any substance which tends to produce cancer in an organism.
carcinogenic - Cancer-producing.
cartridge - Any removable preformed or prepackaged component containing a filtering medium, ion exchanger, membrane, or other treatment material which fits inside a housing to make up a cartridge filter. Also called an element.
cartridge filter - A device often used for single faucet water treatment, made up of a housing and a removable cartridge (element). In high flow rate commercial applications, the elements are clustered in a large housing and the elements are cleanable and reusable. In residential use disposable elements are used.
cathode - The negative pole of an electrolytic system; an electrode where reduction occurs. (See anode.)
cathodic protection - A corrosion control system in which the metal to be protected is made to serve as a cathode, either by the deliberate establishment of a galvanic cell or by impressed current. (See anode.)
cation - A positively charged ion in an electrolyte solution, attracted to the cathode under the influence of a difference in electrical potential. Calcium, magnesium and sodium are cations.
cation exchange - The ion exchange process in which cations in solution are exchanged for other cations available from an ion exchange product.
cation exchange resin - An ion exchange material possessing reverse exchange ability for cations. Sulfonated polystyrene copolymer divinylbenzene exchange resin is used almost exclusively today in ion exchange water softeners.
caustic - 1. Caustic soda (NaOH) or any compound chemically similar to caustic soda. 2. Any substance capable of burning or destroying animal flesh or tissue. The term is usually applied to strong bases.
caustic soda - The common name for sodium hydroxide.
CCE - Abbreviation for "carbon chloroform extract".
channeling - The flow of water or other solution through a limited number of passages in a filter or ion exchanger bed, instead of distributed flow through all passages in the bed. May be due to fouling of the bed and plugging of many passages, poor distributor design, flow rates which are too low, faulty operational procedures, or other causes.
charcoal - an adsorbent carbon product which has about one-third the surface area of activated carbon.
check valve - A valve which will only allow water to pass in one direction but will close to prevent flow (backflow) in the opposite direction.
chelate - To form a complex chemical compound in which an ion, usually metallic, is bound into a stable ring structure.
chelating agent - A chemical compound sometimes fed to water to tie up undesirable metal ions, keep them in solution, and eliminate or reduce the normal effects of the ion. (See sequestering agent.)
chemical stability - Resistance to attack by chemical action. This term is often applied to the resistance of ion exchange resins to breakdown due to contact with aggressive solutions.
chloramines - Chemical complexes formed from the reaction between ammonia and chlorine being used to disinfect many municipal water supplies. Unlike chlorine, chloramines do not combine with organics in the water to form potentially dangerous trihalomethanes (THMs).
chlorinator - A device designed to feed chlorine gas, pellets, or solutions of such as hypochlorites, into a water supply in proportion to the flow of water.
chlorination - The treatment process in which chlorine gas or a chlorine solution is added to water for disinfection and control of microorganisms. Chlorination is also used in the oxidation of dissolved iron, manganese, and hydrogen sulfide impurities.
chlorine (Cl2) - A gas widely used in the disinfection of water and as an oxidizing agent for organic matter, manganese, iron, and hydrogen sulfide.
chlorine demand - A measure of the amount of chlorine which will be consumed by organic matter and other oxidizable substances in a water before a chlorine residual will be found.
clear water iron - See ferrous iron.
coagulant - A material, such as alum, which will form a gelatinous precipitate in water and cause the agglomeration (collection) of finely divided particles into larger particles which can then be removed by settling and/or filtration.
coagulant aid - A material which is not a coagulant, but which improves the effectiveness of a coagulant - often by forming larger or heavier particles, speeding the reactions, or by permitting reduced coagulant dosage.
coagulation - The process in which very small, finely divided solid particles are clumped into larger particles caused by the use of chemicals.
COD - The abbreviation for "Chemical Oxygen Demand".
coliform bacteria - A particular group of bacteria primarily found in human and animal intestines and wastes. These bacteria are widely used as indicator organisms to show the presence of such wastes in water and the possible presence of pathogenic (disease-producing) bacteria. Escherichia coli (E. coli) is one of the fecal coliform bacteria widely used for this purpose.
collector - A device or system designed to collect backwash water from a filter or ion exchange bed. May also be used as an upper distributor to spread the flow of water in down-flow column operation. (See distributor.)
colloid - Very finely divided solid particles which do not settle out of a solution. The removal of colloidal particles usually requires coagulation.
colony-forming units (cfu) - See heterotrophic plate count.
color - The shade or tint imparted to water by substances in true solution, and thus not removed by mechanical filtration; most commonly caused by dissolved organic matter, but may be produced by dissolved mineral matter.
color throw - The discharge of color to the effluent of a filter or ion exchange system by any component. It usually occurs after a period of standing which allows slowly soluble colored matter to accumulate in the system.
column operation - The process in which the solution to be treated is passed through a bed, or column (as in a tank), of filter media or ion exchanger; may be either up-flow or down-flow.
combined available residual chlorine - The concentration of residual chlorine which is combined with ammonia (NH3) and/or organic nitrogen in water as chloramines (or other chloro derivative) yet is still available to oxidize organic matter and utilize its bacterial properties. The combined chlorine compounds are more stable than free chlorine forms, but are somewhat slower in reaction.
compensated hardness - A calculated value based upon the total hardness, the magnesium-to-calcium ratio, and the sodium, iron, manganese concentrations in a water. This value is used to correct for the reduction in hardness removal capacity of a cation exchange water softener, which is caused by the presence of these substances. No single method of calculation has been uniformly accepted.
composite sample - A mixture of a number of single or "grab" samples, intended to produce a typical or average sample. May be made up of equal volumes of individual samples, or of single samples proportioned to variations in flow or usage.
conductance - In water conditioning, the readiness of water to carry electricity; the reciprocal of electrical resistance. The unit of measure for conductance is the siemens (formally called mho), which is the reciprocal of the ohm. (See conductivity, resistance, specific conductance.)
conductivity - The quality or power to carry electrical current; in water; related to the concentration of ions capable of carrying electrical current. (See conductance, electrolyte.)
connate water - Water deposited simultaneously with rock formations and held with essentially no flow; usually occurs deep in the earth, and usually is high in minerals due to long contact with rock.
contained bed - See packed bed.
contaminant - 1. Any undesirable physical, chemical, or microbiological substance or matter in a given water source or supply. Anything in water which is not H2O may be considered a contaminant. 2. Any foreign component present in another substance.
contamination - The introduction of any contaminant into a water source or supply.
corrosion - The gradual decomposition or destruction of a material by oxidation or chemical actions, often due to an electrochemical reaction.
Crenothrix polyspora - One of several types of bacteria which utilize iron in their metabolism and are capable of depositing gelatinous ferric hydroxide. (See iron bacteria.)
cross connection - A direct link between a potable water system and a non-potable water system, which permits undesirable substances to be drawn into the potable water.
cross-sectional area - The area of a plane at a right angle to the direction of flow through a tank or vessel; often expressed in square feet, and related to the flow rate. (Example: 5 gallons per minute per square foot of ion exchanger bed area.)
Cryptosporidium - A common intestinal parasite found in waters contaminated by sewerage or runoff containing animal waste. It causes diarrhea, nausea, and cramps. Individuals with weakened immune systems are at particular risk. Although resistant to chlorine and most oxidizing agents, it is effectively removed by filtration to 1 micron, and can be destroyed by boiling.
cube - A cubic foot of ion exchanger or filter medium.
cubic foot - The volume of a cube whose sides have the length of one foot. The common basis for the measurement of the volume of ion exchangers or loose filter media.
cycle - A series of events or steps which ultimately lead back to the starting point, such as the exhaustion-regeneration cycle of an ion exchange system.