fine gas bubbles (20–80 microns) which become attached to the impurities to be
removed and rise to the water surface together. The impurities or pollutants to be
removed that are on the water surface are called float or scum which are scooped
off by sludge collection means. The clarified water is discharged from the
flotation clarifier’s bottom. The gas flow rate is about 1% of influent liquid flow
rate. The attachment of gas bubbles to the impurities can be a result of physical
entrapment, electrochemical attraction, surface adsorption, and/or gas stripping.
The specific gravity of the bubble-impurity agglomerate is less than one, resulting
in buoyancy or non-selective flotation (i.e., Save-All).
Eutrophication Over-enrichment of a water body with nutrients, resulting in
excessive growth of organisms and depletion of oxygen concentration.
Ground water The supply of fresh water found beneath the earth’s surface (usually
in aquifers) which is often accessed through wells and springs.
Hydrologic cycle The cycle of water through its natural process of evaporation and
precipitation: from the sea, through the atmosphere, to the land and back to the
sea.
Lake An inland body of water, fresh or salt, of considerable size usually greater
than 50 acres (200,000 square meters) and occupying a basin or hollow on the
earth’s surface.
pH An expression of both acidity and alkalinity on a scale of 0–14, with
7 representing neutrality; numbers less than 7 indicate increasing acidity and
numbers greater than 7 indicate increasing alkalinity. Acid rain can increase the
pH level of the water in a lake, thereby killing all life.
Photosynthesis The manufacture by plants of carbohydrates and oxygen from
carbon dioxide and water in the presence of chlorophyll, using sunlight as an
energy source. Plants thereby absorb carbon from the atmosphere with the
process and store it in their forms.
Phytoplankton Usually microscopic aquatic plants, sometimes consisting of only
one cell.
Plankton Those organisms that are unable to maintain their position or distribution
independent of the movement of water or air masses.
Pollution The contamination of a natural ecosystem, especially with reference to
the activity of humans.
Precipitation Any and all forms of water, whether liquid or solid, that fall from the
atmosphere and reach the earth’s surface. A day with measurable precipitation is a
day when the water equivalent of the precipitation is equal to or greater than
0.2 mm.
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
from there to rivers, lakes, or oceans.
Water resources Water in various forms, such as rain, snow, ice, clouds, surface
water, ground water, reclaimed water, or reused water – that is potentially useful
for domestic, industrial, commercial, or recreational applications.
6 Basic Hydrology, Water Resources, and DAF Boat Plant for Lake Restoration
295
removed and rise to the water surface together. The impurities or pollutants to be
removed that are on the water surface are called float or scum which are scooped
off by sludge collection means. The clarified water is discharged from the
flotation clarifier’s bottom. The gas flow rate is about 1% of influent liquid flow
rate. The attachment of gas bubbles to the impurities can be a result of physical
entrapment, electrochemical attraction, surface adsorption, and/or gas stripping.
The specific gravity of the bubble-impurity agglomerate is less than one, resulting
in buoyancy or non-selective flotation (i.e., Save-All).
Eutrophication Over-enrichment of a water body with nutrients, resulting in
excessive growth of organisms and depletion of oxygen concentration.
Ground water The supply of fresh water found beneath the earth’s surface (usually
in aquifers) which is often accessed through wells and springs.
Hydrologic cycle The cycle of water through its natural process of evaporation and
precipitation: from the sea, through the atmosphere, to the land and back to the
sea.
Lake An inland body of water, fresh or salt, of considerable size usually greater
than 50 acres (200,000 square meters) and occupying a basin or hollow on the
earth’s surface.
pH An expression of both acidity and alkalinity on a scale of 0–14, with
7 representing neutrality; numbers less than 7 indicate increasing acidity and
numbers greater than 7 indicate increasing alkalinity. Acid rain can increase the
pH level of the water in a lake, thereby killing all life.
Photosynthesis The manufacture by plants of carbohydrates and oxygen from
carbon dioxide and water in the presence of chlorophyll, using sunlight as an
energy source. Plants thereby absorb carbon from the atmosphere with the
process and store it in their forms.
Phytoplankton Usually microscopic aquatic plants, sometimes consisting of only
one cell.
Plankton Those organisms that are unable to maintain their position or distribution
independent of the movement of water or air masses.
Pollution The contamination of a natural ecosystem, especially with reference to
the activity of humans.
Precipitation Any and all forms of water, whether liquid or solid, that fall from the
atmosphere and reach the earth’s surface. A day with measurable precipitation is a
day when the water equivalent of the precipitation is equal to or greater than
0.2 mm.
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
from there to rivers, lakes, or oceans.
Water resources Water in various forms, such as rain, snow, ice, clouds, surface
water, ground water, reclaimed water, or reused water – that is potentially useful
for domestic, industrial, commercial, or recreational applications.
6 Basic Hydrology, Water Resources, and DAF Boat Plant for Lake Restoration
295