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Calcium |
One of the principal
elements in the earth's crust. When dissolved, in water, calcium is a
factor contributing to the formation of scale and insoluble soap curds
which are a means of clearly identifying hard water. |
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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. |
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Calcium Hypochlorite |
A chemical compound, [Ca(Cl
0)24H2O], used as a bleach and as a source of chlorine in water treatment;
specifically useful because it is stable as a dry powder and can be formed
into tablets. |
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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. |
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Capacity Curve |
A graph of the capacity
versus regenerant levels for an ion exchange unit or system. |
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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. |
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Carbon Chloroform Extract |
The matter adsorbed from a
stream of water by activated carbon, and then extracted from the activated
carbon with chloroform, using a specific standardized procedure; a measure
of the organic matter in a water. |
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Carbon Dioxide |
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. |
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Carbonaceous |
Materials of or derived
from organic substances such as coal, lignite, peat, etc. |
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Carbonaceous Exchanger |
Ion exchange material
produced by the sulfonation of carbonaceous matter. |
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Carbonate |
The CO32 ion. |
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Carbonate Alkalinity |
Alkalinity due to the
presence of the carbonate ion (CO32). |
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Carbonate Hardness |
Hardness due to the
presence of calcium and magnesium bicarbonates and carbonates in water;
the smaller of the total hardness and the total alkalinity. (See temporary
hardness.) |
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Carbonic Acid Formed |
It does not contribute to
total dissolved solids, but does have a pronounced effect on specific
resistance. This effect must be included when estimating the water quality
from a weak base deionizer. Carbonate and bicarbonate alkalinity are
destroyed by cation resin and converted to carbonic acid. To calculate
carbonic acid formed add the carbonates, bicarbonates, and twice the
carbon dioxide. |
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Carboxylic |
An organic acidic group (COOH)
which contributes cation exchange ability to some resins. |
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Cartridge |
Any removable preformed or
prepackaged component containing a filtering media or ion exchanger. |
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Cathode |
The negative pole of an
electrolytic system; an electrode where reduction occurs. (See anode.) |
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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.) |
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Cation |
An ion with a positive
electrical charge. Calcium, magnesium and sodium are cations. |
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Cation Exchange |
Ion exchange process in
which cations in solution are exchanged for other cations from an ion
exchanger. |
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Cation Load Factory |
This is the sum of calcium,
magnesium, sodium, and potassium. It is the sum of all cations. |
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Caustic |
Any substance capable of
burning or destroying animal flesh or tissue. The term is usually applied
to strong bases. |
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Caustic Soda |
The common name for sodium
hydroxide. |
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Cc |
Abbreviation for
"carbon chloroform extract". |
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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. |
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Chelate |
To form a complex chemical
compound in which an ion, usually metallic, is bound into a stable ring
structure. |
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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.) |
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Chemical Stability |
Resistance to attach by
chemical action. |
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Chlorides |
Salts of chloride are
generally soluble. High concentrations contribute to corrosion problems. |
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Chlorinator |
A device designed to feed
chlorine gas or solutions of its compounds, such as hypochlorite, into a
water supply. |
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Chlorine |
A gas, C2, widely used in
the disinfection of water and an oxidizing agent for organic matter, iron,
etc. |
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Chlorine Demand |
A measure of the amount of
chlorine consumed by oxidizable substances in a water before a chlorine
residual will be found. |
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Chronic Health Effect |
The possible result of
exposure over many years to a drinking water contaminant at levels above
its MCL. |
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Coagulant |
A material, such as alum,
which will cause the agglomeration of finely divided particles into larger
particles which can then be removed by settling and/or filtration. |
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Coagulant Aid |
A material which is not a
coagulant, but which improves the effectiveness of a coagulant by forming
larger or heavier particles, speeding the reactions, or by permitting
reduced coagulant dosage. |
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Coagulation |
The process in which very
small, finely divided solid particles are agglomerated into larger
particles. |
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Cod |
The abbreviation for
"Chemical Oxygen Demand". |
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Coliform Bacteria |
A group of microorganisms
used as indicators of water contamination, and the possible presence of
pathogenic (disease producing) bacteria. |
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Coliform |
A group of related bacteria
whose presence in drinking water may indicate contamination by
disease-causing microorganisms. |
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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 downflow
column operation. (See distributor.) |
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Colloid |
Very finely divided solid
particles which do not settle out of a solution; intermediate between a
true dissolved particle and a suspended solid which will settle out of
solution. The removal of colloidal particles usually requires coagulation. |
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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. As measured in a water
analysis, only the intensity of yellow color is reported. |
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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. |
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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 upflow or downflow. |
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Combined Available
Chlorine |
The chlorine present as
chloramine or other chlorine derivatives in a water, but still available
for disinfection and the oxidation of organic matter. Combined chlorine
compounds are more stable than free chlorine forms, but are somewhat
slower in disinfection action. |
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Community Water System |
A water system which
supplies drinking water to 25 or more of the same people year-round in
their residences. |
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Compensated Hardness |
A calculated value based on
the total hardness, the magnesium to calcium ratio and the sodium
concentration of a water. It is used to correct for the reductions in
hardness removal capacity caused by these factors in zeolite exchange
water softeners. No single method of calculation has been widely accepted. |
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Compliance |
The act of meeting all
state and federal drinking water regulations. |
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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. |
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Concentration Factor |
A number used to estimate
the scaling potential in reverse osmosis systems when the TADS rejection
is expected to exceed 90%; equal to the reciprocal of 1 minus the recovery
ratio. When multiplied by the feed TADS, the result is the approximate
waste water TADS. (See recovery, rejection.) |
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Conductance |
In water conditioning, the
readiness of water to carry electricity; the reciprocal of electrical
resistance. The unit of measure for conductance is the mho (reciprocal
ohm). Used to approximate the dissolved solids content of water. (See
conductivity, resistance, specific conductance.) |
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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.) |
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Connate Water |
Water deposited
simultaneously with rock and held with essentially no flow; usually occurs
deep in the earth, and usually is high in minerals due to long contact. |
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Contaminant |
Anything found in water
(including microorganisms, minerals, chemicals, radionuclides, etc.) which
may be harmful to human health. |
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Contamination |
The presence of foreign
matter in a substance which reduces the value of the substance, or
interferes with its intended use. |
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Conversion |
See "recovery". |
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Corrosion |
The disintegration of a
metal by electrochemical means. |
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Crenothrix Polyspora |
A genus of filamentous
bacteria which utilize iron in their metabolism, and cause staining,
plugging and taste and odor problems in water systems. (See iron
bacteria.) |
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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. |
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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.) |
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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 micrometer, and can be destroyed by boiling. |
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Cryptosporidium |
A microorganism commonly
found in lakes and rivers which is highly resistant to disinfection.
Cryptosporidium has caused several large outbreaks of gastrointestinal
illness, with symptoms that include diarrhea, nausea, and/or stomach
cramps. People with severely weakened immune systems (that is, severely
immuno-compromised) are likely to have more severe and more persistent
symptoms than healthy individuals. |
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Cube |
A slang expression
sometimes used to mean a cubic foot of ion exchanger or filter media. |
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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. |
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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. |
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Cysts |
Common cysts include
Cryptosporidia and Giardia. Because cysts have a "hard shell,"
they are able to survive in hostile environments, such as the presence of
chlorine or absence of water. It is because of this hard shell that they
are hard to kill. Once the cyst is ingested, the shell is discarded and
the organisims infect the intestines, causing diarrhea, headaches,
abdominal cramps, nausea and vomiting. |