medium of some kind (granular, diatomaceous
of the ultimate user of a military water system, except in
earth, woven, or porous) while the liquid passes
the case of turbidity where the maximum permissible
through.
level is measured at the point of entry the distribution
system. Contaminants added to the water under
circumstances controlled by the user, except those
Freshwater - Freshwater has a TDS concen-
resulting from corrosion of piping and plumbing caused
tration of less than 1,500 ppm. Brackish waters
by water quality, are excluded from this definition.
are highly mineralized and have a TDS
concentration between 1,500 ppm and 15,000
Membrane Filtration - A method of quantitative or
ppm. Saltwaters have a TDS concentration
greater than 15,000 ppm.
qualitative analysis of bacterial or particulate matter in a
water sample by filtration through membrane capable of
retaining bacteria.
Gallery - (1) An underground structure designed
and installed for the purpose of collecting
Milligrams Per Liter - A unit of the concentration of water
subsurface water. (2) A passageway in a
structure, such as a dam, used for obtaining
or wastewater constituent. It has replaced the parts per
access to interior parts, or to carry pipes, or to
million unit, to which it is approximately equivalent, in
house machinery.
reporting the results of water analyses.
Ground Water - Water occurring in a stratum
Nonpotable Water - Water that has not been examined,
(aquifer) below the surface of the ground. The
properly treated, and approved by appropriate
term is not applied to water which is percolating
authorities as being safe for soldiers' consumption. All
or held in the top layers of the soil but to that
waters are considered nonpotable until declared potable.
below the water table.
Osmosis - The passage of a liquid from a weak solution
to a more concentrated solution across a
to the existence therein of the carbonates and
semipermeable membrane. The membrane allows the
sulfates (and occasionally the nitrates and
passage of the water (solvent) but not the dissolved
chlorides) of calcium, iron, and magnesium.
solids (solutes). This process tends to equalize the
Causes curding of water when soap is used,
conditions of either side of the membrane.
increased consumption of soap, deposition of
scale in boilers, injurious effects in some
Particulate - A very small solid suspended in water which
industrial processes, and sometimes
can vary widely in size, shape, density, and electrical
objectionable taste in the water. Commonly
charge. Colloidal and dispersed particulates are
computed from the amounts of calcium and
artificially gathered together by the processes of
magnesium in the water and expressed as
coagulation and flocculation.
equivalent calcium carbonate.
Peak Demand - The maximum load placed on a water
Infiltration - (1) The flow or movement of water
system. This is usually the maximum average load over
through the pores of a soil or other porous
a period of time such as peak hourly demand, peak daily
medium. (2) The absorption of liquid water by
demand, or instantaneous peak demand.
the soil, either as it falls as precipitation or from
a stream flowing over the surface. Also called
Permeability - The property of a material which permits
seepage.
appreciable movement of water through it when
saturated and actuated by hydrostatic pressure of the
Influent - Water flowing into a reservoir, basin, or
magnitude normally encountered in natural subsurface
treatment operation.
water. The rate of permeability is measured by the
quantity of water passing through a unit cross section in
Level, Static - The elevation of water table or
a unit time when the gradient of the energy head is
pressure surface when it is not influenced by
unity.
pumping or other form of extraction from the F
round water body. It is the level of ground water
in a well before pumping.
other harmful or objectionable material to water. A
general term that does not necessarily signify the
Maximum Permissible Concentration - The
presence of disease-producing bacteria.
maximum permissible level of a contaminant in
water which is delivered to a free-flowing outlet
A-3
QM 4924
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