Nicholas P. Cheremisinoff. Handbook of Solid Waste Management and Waste Minimization Technologies
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Upflow Tank - (1) A sedimentation tank in which water or waste water enters near
the bottom and rises vertically, typically through a blanket of previously settled
solids. The clarified liquid flows out at the top and settled sludge flows out the
bottom. (2) A vertical-flow tank.
Upset - An upset digester does not decompose organic matter properly. The digester
is characterized by low gas production, high volatile acid/alkalinity relationship, and
poor liquid/solids separation. A digester in an upset condition is sometimes called a
"sour" or "stuck" digester.
Upstream Side - The feed side of the filter.
Uronic Acid - Class of acidic compounds of the general formula
HOOC(CHOH)
n
CHO that contain both carboxylic and aldehydic groups, are
oxidation products of sugars, and occur in many polysaccharides; especially in the
hemicelluloses.
Useful Life - Determined when contamination causes an adverse flow rate, low
efficiency, or high differential pressure.
UV Ozone - A powerful wastewater treatment process employing ozone in solution
and ultraviolet light; oxidizes COD and toxic substances, removes color, and
disinfects.
V
Vacuum - A space condition that is characterized by pressure lower than
atmospheric. This condition is created when air is pumped out of an unvented space.
Vacuum Breaker - A device for relieving a vacuum or partial vacuum formed in a
pipeline to prevent backsiphoning.
Vacuum Filter - A filter used to accomplish sludge dewatering and consisting of a
cylindrical drum mounted on a horizontal axis, covered with filter medium, and
revolving partially submerged in a dilute sludge mixture. See vacuum filtration.
Vacuum Filtration - A continuous filtration operation that is typically accomplished
on a rotating cylindrical drum. As the drum rotates, part of its circumference is
subject to an internal vacuum that draws sludge to the filter medium and removes
water for subsequent treatment. The dewatered sludge cake is released by a scraper.
Vacuum Gauge - A gauge that indicates the pressure of the air or gas in a partial
vacuum.
Vadose Zone - Unsaturated zone of soil above the groundwater, extending from the
bottom of the capillary fringe all the way to the soil surface.
Valence - An integer representing the number of hydrogen atoms with which one
atom of an element (or one radical) can combine (negative valence), or the number
of hydrogen atoms the atom or radical can displace (positive valence).
Valve - A device installed in a pipeline to control the magnitude and direction of
flow. It consists of a shell and a disc or plug fitted to the shell.
Valve Seat - The surface on which a valve rests.
Valve Throttling - To control or modulate flow through a system by manually or
automatically opening or closing a valve to various degrees. In a pumped system,
changing the discharge valve to various positions between full open and full closed
regulates the amount of discharge head. Gate valves and plug valves are often used
to throttle the discharge of centrifugal pumps.
Vapor - (1) The gaseous form of any substance. (2) A visible condensation such as
fog, mist, or steam that is suspended in air.
Vapor Dispersion - The movement of vapor clouds or plumes in the air due to
wind, gravity, spreading, and mixing.
Vapor Extraction - A technique that makes use of a partial vacuum to remove
volatile and semi-volatile contamination, such as hydrocarbons, from soils.
Vapor Pressure - Pressure exerted by a vapor in a confined space. It is a function
of the temperature.
Vapor Recovery System - A system by which the volatile gases from gasoline are
captured instead of being released into the atmosphere. Recovery systems may be
required for gasoline stations in some cities and other nonattainment areas.
Vaporization - The process by which a substance such as water changes from the
liquid or solid state to the gaseous state.
Variable-frequency Drive (VFD) - An electronic controller that adjusts the speed of
an electric motor by modulating the power being delivered. These drives provide
continuous control, matching motor speed to the specific demands of the work being
performed.
V-belt Drive - A type of pump coupling that consists of a belt of triangular shape
running on sheaves or pulleys with similarly shaped grooves. The movement of the
belt in the groove creates a wedging action that improves the traction of the system
and therefore gives it more pulling power than a round or flat belt system.
V-belt Drive Pulley - A disc-shaped object that rotates around a fixed center. The
outside edges of the disk are grooved to hold the belts. Also known as a sheave.
Vector - (i) Plasmid or virus used in genetic engineering to insert genes into a cell,
(ii) Agent, usually an insect or other animal, able to carry pathogens from one host
to another.
Vector Attraction - The characteristic of sewage sludge that attracts rodents, flies,
mosquitoes or other organisms capable of transporting infectious agents.
Vector Attraction Reduction - Decreasing the characteristic of sewage sludge that
attracts rodent, flies, mosquitoes, or other organisms capable of transmitting
infectious agents.
Vegetative - Actually growing state.
Vegetative Cell - Growing or feeding form of a microbial cell, as opposed to a
resting form such as a spore.
Velocity Head - (1) The vertical distance or height through which a body would
have to fall freely, under the force of gravity, to acquire the velocity it possesses. It
is equal to the square of the velocity divided by twice the acceleration of gravity. (2)
The theoretical vertical height through which a liquid body may be raised by its
kinetic energy.
Velocity Meter - A vaned water meter that operates on the principle that the vanes
of the wheel move at approximately the same velocity as the flowing water.
Venturi Aerator - A submerged jet aeration device in which the liquid to be aerated
is pumped through a nozzle within a larger diameter tube, causing air entrainment
and vigorous liquid mixing.
Venturi Meter - A differential meter for measuring the flow of water or other fluid
through closed conduits or pipes. It consists of a Venturi tube and one of several
proprietary forms of flow-registering devices. The difference in velocity heads
between the entrance and the contracted throat is an indication of the rate of flow.
Venturi Scrubber - A device that removes submicron particles and reactive trace
gases from gas streams by passing the gas at high velocity through the scrubbing
liquor, ensuring vigorous mixing.
Vertical Pump -(I)A reciprocating pump in which the piston or plunger moves in
a vertical direction. (2) A centrifugal pump in which the pump shaft is in a vertical
position.
Vertical Screw Pump - A pump, similar in shape, characteristics, and use to a
horizontal screw pump, but which has the axis of its runner in a vertical position.
Vesicles - Spherical structures, formed intracellularly, by some arbuscular
mycorrhizal fungi.
Viable Count - Measurement of the concentration of live cells in a microbial
population.
Vibration Sensor - An on-line sensor to monitor trends in equipment vibration to
detect problems before failure.
Vibrio - (1) Curved, rod-shaped bacterial cell. (2) Bacterium of the genus Vibrio.
Virion - Virus particle; the virus nucleic acid surrounded by protein coat and in
some cases other material.
Virulence - Degree of pathogenicity of a parasite.
Virus - Any of a large group of submicroscopic infective agents that typically
contain a protein coat surrounding a nucleic acid core and are capable of growth
only in a living cell.
Viscosity - Molecular attractions with a fluid that makes it resist a tendency to
deform under applied forces.
V-notch Weir - A triangular weir with the apex of the triangle submerged in fluid.
Void - A pore or open space in rock or granular material not occupied by solid
matter. It may be occupied by air, water, or other gaseous or liquid material. Also
called interstice or void space.
Volatile - A volatile substance is one that is capable of being evaporated or changed
to a vapor at a relatively low temperature. Volatile substances also can be partially
removed by air stripping.
Volatile Acids - Fatty acids containing six or fewer carbon atoms. They are soluble
in water and can be steam distilled at atmospheric pressure. They have pungent
odors and are often produced during anaerobic decomposition.
Volatile Organic Compounds (VOCs) - Substances such as solvents that are liquid
at room temperature, but vaporize significantly and take part in the generation of
ozone pollution in the lower atmosphere.
Volatile Solids (VS) - Materials, typically organic, that can be driven off from a
sample by heating, typically to 55O
0
C with nonvolatile inorganic solids (ash)
remaining.
Volatile Suspended Solids (VSS) - That fraction of suspended solids, including
organic matter and volatile inorganic salts, that will ignite and burn when placed in
an electric muffle furnace at 55O
0
C.
Volume Resistivity - Or specific resistivity of a material, expressed in W/cm.
Resistance to electrical current flow through the bulk of an object.
Volute - One of the two main components of a centrifugal pump; the other is the
impeller. The volute forces the liquid to discharge from the pump. This is
accomplished by offsetting the impeller in the volute and by maintaining a close
clearance between the impeller and the volute at the cutwater.
Vortex - A revolving mass of water in which the streamlines are concentric circles
and the total head for each streamline is the same.
VS/L - Measure of volatile solids, usually expressed as g VS/l/day (grams volatile
solids per liter per day).
W
Waste Activated Sludge (WAS) - Solids removed from the activated-sludge process
to prevent an excessive buildup in the system.
Waste Incineration - Incineration of waste at high temperatures in two stages to
promote efficient combustion to an ash and carbon dioxide.
Waste Minimization - The analysis and revision of the use of materials, processes,
equipment, and procedures in order to reduce the unnecessary use of energy and
resources, to reduce the generation of effluents and wastes, and to recycle where
practical.
Wastewater - The used water and solids from a community that flow to a treatment
plant. Stormwater, surface water, and groundwater infiltration also may be included
in the wastewater that enters a wastewater treatment plant. The term "sewage"
usually refers to household wastes, but this word is being replaced by the term
wastewater.
Water-retention Curve - Graph showing soil-water content as a function of
increasingly negative soil water potential.
Wastewater Treatment Plant (WWTP) - A plant that treats urban wastewater and
some of the runoff collected in the combined sewer system, and discharges the
treated effluent to a receiving waterbody.
Water Column - (1) Water above the valve in a set of pumps. (2) A measure of
head or pressure in a closed pipe or conduit.
Water Content - Water contained in a material expressed as the mass of water per
unit mass of oven-dry material.
Water Hammer - The phenomenon of oscillations in the pressure of water about its
normal pressure in a closed conduit, flowing full, which results from a too-rapid
acceleration or retardation of flow. Momentary pressures greatly in excess of the
normal static pressure may be produced in a closed conduit by this phenomenon.
Water Treatment Plant (WTP) - A plant that treats raw water for use as potable
(drinkable) water.
Watershed - A topographically defined area or region of land drained by a
river/stream or system of rivers/streams such that all outflows are discharged
through a single outlet.
Wearing Ring - A replaceable metal ring that is incorporated in the pump at the
point where the clearance between the pump casing and the impeller are the closest.
The wear ring can be placed on the casing, on the impeller, or at both locations.
When these rings reach their wear limits, they can be replaced. This restores the
design clearance on the parts and keep the pump operating as efficiently as possible.
Weathering - All physical and chemical changes produced in rock by atmospheric
agents.
Weeping Tile - A weeping tile (or foundation drain) is a perforated pipe that is
located along the foundation of buildings to collect groundwater infiltration flows
and route them to a sump pump for disposal on the surface, or a sewer service for
disposal in a sewer.
Weir - A device that has a crest and some side containment of known geometric
shape, such as a V, trapezoid, or rectangle, and is used to measure flow of liquid.
The liquid surface is exposed to the atmosphere. Flow is related to the upstream
height of water above the crest, position of crest with respect to downstream water
surface, and geometry of the weir opening.
Wet Air Oxidation - A process that treats wastewater containing high strength or
hazardous organic chemicals by a combination of high temperature and pressure that
creates highly reactive hydroxyl radicals.
Wet Well - A component of a pumping station that creates a reservoir of the fluid
from which the pumps draw their suction.
Wetlands - Areas that are inundated or saturated by surface or groundwater at a
frequency and duration sufficient to support, under normal circumstances, a
prevalence of vegetation typically adapted for life in saturated soil conditions.
Wetlands generally include swamps, marshes, bogs and similar areas. Constructed
wetlands for wastewater treatment are not included.
White Rot Fungus - Fungus that attacks lignin, along with cellulose and
hemicellulose, leading to a marked lightening of the infected wood.
Wild Type - Strain of microorganism isolated from nature. The usual or native form
of a gene or organism.
Winogradsky Column - Glass column with an anaerobic lower zone and an aerobic
upper zone, which allows growth of microorganisms under conditions similar to
those found in nutrient-rich water and sediment.
Wire-to-water Efficiency - The ratio of mechanical output of a pump to the
electrical input at the meter.
Worm Gear Reducer - A gear consisting of a short-rotating screw and a toothed
wheel.
Woronin Body - Spherical structure associated with the simple pore in the septa
separating hyphal compartments of fungi in the phylum Ascomycota.
X
Xenobiotic - Compound foreign to biological systems. Often refers to human-made
compounds that are resistant or recalcitrant to biodegradation and decomposition.
Xerophile - Organism adapted to grow at low water potential, i.e., very dry
habitats.
Y
Yeast - Fungus whose thallus consists of single cells that multiply by budding or
fission.
Z
Z-list - OSHA's Toxic and Hazardous Substances Tables (Z-I, Z-2, and Z-3) of air
contaminants; any material found on these tables is considered hazardous.
Zone of Saturation - The layer beneath the surface of the land in which all openings
are filled with water.
Zoogleal Film - A complex population of organisms that form a "slime growth" on
a trickling-filter medium and break down the organic matter in wastewater.
Zoogleal Mass - Jelly-like masses of bacteria found in both the trickling-filter and
activated sludge processes.
Zoospore - An asexual spore formed by some fungi that usually can move in an
aqueous environment via one or more flagella.
Zygospore - Thick-walled resting spore resulting from fusion of two gametangia of
fungi in the phylum Zygomycota.
Zygote - In eukaryotes, the single diploid cell resulting from the union (fusion) of
two haploid gametes.
Zymogenous Flora - Refers to microorganisms, often transient or alien, that
respond rapidly by enzyme production and growth when simple organic substrates
become available. Also called copiotrophs.
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Index
Index terms Links
A
acetaldehyde 191
acetate 102
acetic acid 16
acetone 16 190
acetonitrile 191
acrylic engineering polymers 189
acrylic fibers 190
acrylonitrile butadiene styrene 189
acrylonitrile 190
activated alumina 191
activated carbon 191 192
activated sludge 145 192
aerobic bacteria 102 181
Aerometric Information Retrieval System (AIRS) 272
afterburners 49 62
agglomerates 133
aggregate 150
agrochemicals 189
agro-industry chemicals 194
air emissions 18
air permitting 18
air pollution control devices 147
air pollution control 148
air pollution controls 7 158 168