Calibration: The process of setting
equipment to a satandard measure.
Catchment: The area of land from which surface and ground water drains
into a river or other watercourses (streams, wetlands).
Chemicals: The product of residual disinfectant concentration (C)
in milligrams per litre determined before or at taps providing water for human consumption, and the
corresponding disinfectant contact time (t) in minutes.
Chemical addition: The adding of extra chemicals to a process to bring about a change.
Chemical characteristics: The characteristics or properties of a chemical, including physical, chemical and biological.
Chemical dosing: Involves the addition
of chemicals in a process. For example dosing with coagulants.
Chloramination: A form of disinfection
which involves dosing water with chlorine and ammonia.
Chloramines (KLOR-uh-means): Compounds formed by the reaction of
hypochlorous acid (or aqueous chlorine) with ammonia.
Chlorination (KLOR-uh-NAY-shun): The application of chlorine to water,
generally for the purpose of disinfection, but frequently for accomplishing other biological or chemical results
(aiding coagulation and controlling tastes and odours).
Chlorine: Highly toxic chemical
used for disinfection of water, usually comes in a yellow/green gas.
Chlorine meter: An electronic meter containing a sensor which can measure chlorine levels in water or air.
Coagulant (CO-ag-YOU-lents): Chemicals that cause very fine particles to
clump together into large particles. This makes it easier to separate the solids from the water by settling, skimming,
draining, or filtering.
Coagulate: Chemical process used as a precursor to flocculation for the removal
of colloidal material.
Coagulation (CO-ag-you-LAY-shun): The clumping together of very fine particles
into larger particles caused by the use of chemicals (coagulants). The chemicals neutralise the electrical charges of
the fine particles and cause destabilisation of the particles. This clumping together makes it easier to separate the
solids from the water by settling, skimming, draining, or filtering.
Coliform (COAL-i-form):
A group of bacteria (faecal coli forms) which are found in the intestine of warm blooded animals (including humans) and
also in plants, soil, air and water. The presence of coliform bacteria is an indication that the water is polluted and
may contain pathogenic organisms.
Colloidal matter: Very fine particles which do not settle (or precipitate) but
remain in suspension in a liquid. Removed from the water by coagulation and subsequent settling and/or filtration.
Colloids (COE-loids): Very small, finely divided solids (particles that do not
dissolve) that remain dispersed in liquid for a long time due to their small size and electrical charge. When most of
the particles in water have a negative electrical charge, they tend to repel each other. This repulsion prevents the
particles from clumping together, becoming heavier, and settling out.
Colorimetric measurement: A means of measuring unknown chemical concentrations
in water by measuring a sample's colour intensity. The specific colour of the sample , developed by the addition of
chemical reagent, is measured with a photoelectric colorimeter or is compared with "colour standards" using, or
corresponding with , known concentrations of the chemical.
Colour: A visual property that humans sense as black, red, blue etc. Caused by the wavelength on object reflects that interacts with the eye.
Combustion products: Combustion products, for example, water, or ash,
or carbon dioxide, are formed by burning. Heat chemically alters organic compounds, converting them into stable
inorganic substances like carbon dioxide and water.
Some combustion products can be explosive or toxic. Combustion Product Hazards are listed as required on MSDSs.
Always follow MSDS directions for personal protective equipment and other safety precautions.
Composite (proportional) sample (COM-pas-it):
A composite sample is a collection of individual samples obtained at regular
intervals, usually every one or two hours during a 24-hour time span.
Each individual sample is combined with the others in proportion to the
rate of flow when the sample was collected. The resulting mixture (composite
sample) forms a representative sample and is analysed to determine the
average conditions during the sampling period.
Compound:
A substance composed of two or more elements whose composition is constant. For example,
table salt (sodium chloride NaCl) is a compound.
Consumer: An individual or organisation that uses drinking water.
Corrective action: Procedures to be followed when monitoring results indicate
a deviation occurs from acceptable criteria (adapted from Codex Alimentarius).
Corrosive: A substance that causes
a destructive effect on another substance. For example an acid.
Clarification: A process used to improve water by separating and removing suspended solids from the water.
Clarifier: A large circular or rectangular basin or tank in which wateris held for a specific time to allow heavy suspended solids to settle.
Clarified Water: Water that has had suspended solids removed to reduce turbidity, usually by one of several clarification processes.
Cryptosporidium: Cryptosporidium is a micro-organism commonly found in lakes and
rivers that is highly resistant to disinfection. Cryptosporidium has caused several large outbreaks of gastrointestinal
illness, with symptoms that include diarrhoea, nausea and stomach cramps. People with severely weakened immune systems
(ie, severely immuno-compromised people) are likely to have more severe and more persistent symptoms than healthy individuals
(adapted from United States Environmental Protection Agency).
Cyanobacteria: Cyanobacteria is a bacteria containing chlorophyll and phycobilins,
commonly known as 'blue-green algae'.