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Ultra-violet
(UV) oxidation:
A process using extremely
short wave-length light that can kill micro-organisms (disinfection) or cleave
organic molecules (photo oxidation) rendering them polarized or ionized and
thus more easily removed from the water.
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Unclassified
waters: Those
waters for which no classification has been assigned and which have not been
identified in Appendix A of 31 Texas Administrative Code, Chapter 307.10 of
Title 31 (relating to definitions).
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Unconsolidated
formations: Naturally
occurring earth formations that have not been lithified. Alluvium, soil, gravel,
clay, and overburden are some of the terms used to describe this type of formation.
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Undercurrent: A current below
the upper currents or surface of a fluid body.
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Underdrain: A concealed drain
with openings through which the water enters when the water table reaches the
level of the drain.
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Underflow: Movement of water
through subsurface material.
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Underground
storage tank:
A tank located all or partially
underground that is designed to hold gasoline or other petroleum products or
chemical solutions.
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Undertow: The current beneath
the surface that sets seaward or along the beach when waves are breaking on
the shore.
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Underwater: Under the surface
of the water; lying, growing, performed, worn, or operating below the surface
of the water, as underwater caverns, underwater operation of a submarine.
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Unit surcharge: A surcharge imposed
for all water use above a threshold level for excess consumption established
based on average per capita or per-household consumption.
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Unloading: The release of
the contaminant that was captured by a filter medium.
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Unsaturated
Zone: The area
above the water table where soil pores are not fully saturated with water.
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Upflow: An upward flow.
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Upwater: Ultra pure water
creation demands a specialised way of working. A number of techniques are used
amongst others; membrane filtration, ion exchanges, sub micron filters, UV and
ozone systems. The produced water is extremely pure and contains none to very
low concentrations of salts, organic/ pyrogene components, oxygen, suspended
solids and bacteria.
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Urban runoff: Storm water from
city streets and adjacent domestic or commercial properties that may carry pollutants
of various kinds into the sewer systems and/or receiving waters.
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USGS: United States
Geological Survey.
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Utility: Public water
service provider.
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UV: Ultra Violet.
Radiation that has a wavelength shorter than visible light. It is often used
to kill bacteria and destroy ozone.
