Glossary Of Water Treatment Industry Terms . . . "F"
fecal - Matter containing or derived
from animal or human wastes or feces.
filter- A device or system for the removal
of solid particles (suspended solids).
filter area - The effective area
through which water passes through filter media, often expressed in
square feet. (See cross sectional area.)
filter medium - (See medium.)
filtrate - The effluent liquid from
fines - Extremely small particles of
filter media or ion exchange material, often the result of breakage
or chemical or physical deterioration.
fixed solids - The suspended or
dissolved solids remaining after ignition, usually at 600oCl;
usually due to inorganic matter which is not volatilized at the ignition
fixture - In plumbing, a permanently
installed device in which water is used, such as a faucet or toilet.
fixture unit - An arbitrary unit
assigned to different types of plumbing fixtures, and used to estimate
flow rate requirements and drain capacity requirements.
floc - An agglomeration of finely divided
suspended particles in a larger, usually gelatinous particle the result
of physical attraction or adhesion to a coagulant compound.
flocculation - The process of
causing a "floc" to form after treatment with a coagulant
by gentle stirring or mixing. (See coagulation.)
flow control- A device designed
to limit or restrict the flow of water or regenerant; may include
a throttling valve, an orifice of fixed diameter, or a pressure compensating
flow rate- The quantity of water
or regenerant which passes a given point in a specified unit of time,
often expressed in gallons per minute.
fluoridation- The addition of
a fluoride compound to a water supply for the reduction in incidence
of dental caries.
flush tank- A tank or chamber in
which water is stored for rapid release.
flush valve- A self-closing valve
designed to release a large volume of water when tripped.
FMA - Abbreviation for free mineral acidity
(see mineral acidity).
fouling - The process in which undesirable
foreign matter accumulates in a bed of water conditioning media, clogging
pores and coating surfaces and thus inhibiting or retarding the proper
operation of the bed.
free available chlorine - The concentration
of residual chlorine present as dissolved gas, hypochlorous acid or
hypochlorite, not combined with ammonia or in other less readily available
freeboard- The vertical distance
between a bed of filter media or ion exchange material and the overflow
or collector for backwash water; the height above the bed of granular
media available for bed expansion during backwashing; may be expressed
either as a linear distance or a percentage of bed depth.
free carbon dioxide - Carbon dioxide
present in water as the gas, or as carbonic acid, but not that combined
in carbonates or bicarbonates.
free chlorine- See free available
free mineral acidity - See mineral acidity.