423CAUSTIC SODA: Also known as sodium hydroxide and is used to raise pH.
CAUSTIC: NaOH (also called Sodium Hydroxide) is a strong chemical used in the treatment
process to neutralize acidity, increase alkalinity or raise the pH value.
CEILING AREA: The specific gravity of ammonia gas is 0.60. If released, this gas will accumulate
first at the ceiling area. Cl2 gas will settle on the floor.
CELL POTENIAL: The force in a galvanic cell that pulls electron through reducing agent to
oxidizing agent.
CENTRIFUGE: Equipment used to separate substances based on density by rotating the tubes
around a centered axis
CESIUM (also Caesium): Symbol Cs- A soft, silvery-white ductile metal, liquid at room
temperature, the most electropositive and alkaline of the elements, used in photoelectric cells and
to catalyze hydrogenation of some organic compounds.
CHAIN OF CUSTODY (COC): A record of each person involved in the possession of a sample
from the person who collects the sample to the person who analyzes the sample in the
laboratory.
CHECK VALVE: Allows water to flow in only one direction.
CHELATION: A chemical process used to control scale formation in which a chelating agent
"captures" scale-causing ions and holds them in solution.
CHEMICAL FEED RATE: Chemicals are added to the water in order to improve the subsequent
treatment processes. These may include pH adjusters and coagulants. Coagulants are
chemicals, such as alum, that neutralize positive or negative charges on small particles, allowing
them to stick together and form larger particles that are more easily removed by sedimentation
(settling) or filtration. A variety of devices, such as baffles, static mixers, impellers and in-line
sprays, can be used to mix the water and distribute the chemicals evenly.
CHEMICAL LAW: Certain rules that pertain to the laws of nature and chemistry.
CHEMICAL OXIDIZER: KMnO4 or Potassium Permanganate is used for taste and odor control
CHEMICAL REACTION RATE: In general, when the temperature decreases, the chemical
reaction rate also decreases. The opposite is true for when the temperature increases.
CHEMICAL REACTION: The change of one or more substances into another or multiple
substances.
CHEMISORPTION: (or chemical adsorption) Is adsorption in which the forces involved are
valence forces of the same kind as those operating in the formation of chemical compounds.
CHLORAMINATION: Treating drinking water by applying chlorine before or after ammonia. This
creates persistent disinfectant residual called chloramines.
CHLORAMINES: A group of chlorine ammonia compounds formed when chlorine combines with
organic wastes in the water. Chloramines are not effective as disinfectants and are responsible
for eye and skin irritation as well as strong chlorine odors.
CHLORINATION: The process in water treatment of adding chlorine (gas or solid hypochlorite)
for purposes of disinfection.
CHLORINE DEMAND: Amount of chlorine required to react on various water impurities before a
residual is obtained. Also, means the amount of chlorine required to produce a free chlorine
residual of 0.1 mg/l after a contact time of fifteen minutes as measured by iodmetic method of a
sample at a temperature of twenty degrees in conformance with Standard methods.
CHLORINE FEED: Chlorine may be delivered by vacuum-controlled solution feed chlorinators.
The chlorine gas is controlled, metered, introduced into a stream of injector water and then
conducted as a solution to the point of application.
CHLORINE, FREE: Chlorine available to kill bacteria or algae. The amount of chlorine available
for sanitization after the chlorine demand has been met. Also known as chlorine residual.
CHLORINE: A chemical used to disinfect water. Chlorine is extremely reactive, and when it
comes in contact with microorganisms in water it kills them. Chlorine is added to swimming pools
to keep the water safe for swimming. Chlorine is available as solid tablets for swimming pools.
Some public water system’s drinking water treatment plants use chlorine in a gas form because
of the large volumes required. Chlorine is very effective against algae, bacteria and viruses.
Protozoa are resistant to chlorine because they have thick coats; protozoa are removed from
drinking water by filtration.