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Terms & Definitions
A - B - C -
D - E - F - G
- H - I - J - K
- L - M - N - O
- P - Q - R - S
- T - U - V - W
- X - Y - Z
A
- ABSORPTION:
- The penetration of one substance into the inner structure of another.
-
- ACIDULATE:
- Treatment with acid to lower the pH. Also refers to an emulsion breaking process.
-
- ACTIVATED SLUDGE:
- Sludge particles produced in raw or settled wastewater (primary
effluent) by the growth of microbiological organisms. Activate sludge
is different from primary sludge in
that the sludge particles contain many living
organisms (bacteria, fungi & protozoa), which use the incoming
wastewater as a source of food.
-
-
ACTIVATED SLUDGE PROCESS:
- A biological wastewater treatment process which
converts soluble organics into settable insoluble solids through the
use of microorganisms. The solids are
collected in a sedimentation step (see Secondary
Clarifier) and returned to the aeration basin (RAS) or wasted
(WAS) as the operation characteristics of the system dictate.
-
- ACRYL AMIDE:
- The chemical compound that results when one hydrogen atom in
ammonia is replaced by acrylic acid.
-
- ACRYL ATE:
- A salt or ester of acrylic acid.
-
-
ADVANCED WASTE TREATMENT:
- Any process that upgrades treated wastewater
to meet specific reuse standards. May also be referred to as tertiary
treatment.
-
- ADSORPTION:
- The adherence of dissolved colloidal or finely divided solids onto
the surface of solid particle or body in which they come into
contact.
-
- AERATION:
- The process of air addition. In wastewater treatment, this process
serves two purposes: 1). Mixing & 2). Oxygen addition to support
microorganisms.
-
- AERATION TANK:
- The tank where raw or returned activated sludge is mixed
and aerated.
-
- AEROBES:
- Bacteria that must have dissolved oxygen present to survive.
-
- AEROBIC:
- A condition in which dissolved or “free” oxygen is present in the
aquatic environment.
-
- AEROBIC BACTERIA:
- Bacteria that live and reproduce only in an environment
where dissolved oxygen is present.
-
- AEROBIC DIGESTION:
- The decomposition of wastes by microorganisms in the
presence of dissolved oxygen.
-
- AGGLOMERATION:
- The growth or clumping of smaller particles into larger particles or floc,
which will rapidly settle.
-
- ALUM:
- Aluminum sulfate coagulant. Usually provided in liquid form but can be
used in “dry” form as well.
-
- ANAEROBIC:
- A condition in which “free” or dissolved oxygen is not present.
-
- ANAEROBIC BACTERIA:
- Bacteria that live and reproduce in an environment
containing no “free” or dissolved oxygen.
-
- ANAEROBIC DIGESTION:
- Wastewater solids, usually at 5% solids, that are decomposed by bacteria
in the absence of dissolved oxygen.
-
- ANIONIC SURFACTANT:
- An ionic type of cleaning product that contains
a negatively charge surface-active agent.
-
- ASEPTIC:
- A sterile or germ free environment.
B
- BOD:
- An abbreviation for the term, Biochemical Oxygen Demand. It is the rate at
which microorganisms’ use dissolved oxygen in water or wastewater
for the conversion of dissolved organics into cellular material.
-
-
BIOCHEMICAL OXYGEN DEMAND TEST:
- A laboratory procedure that measures the rate of oxygen use under
controlled conditions of time and temperature.
-
- BIOMASS:
- A mass or clump of living organisms feeding on wastes, dead organisms
or debris in wastewater.
-
- BULKING:
- Clouds of billowing sludge usually associated with algae or bacteria in
secondary clarifiers when the sludge becomes too light to settle
properly.
C
- CENTRIFUGE:
- A mechanical device that uses gravitational forces at high speed to
separate solids from liquids.
-
-
CHEMICAL OXYGEN DEMAND:
- A measure of the rate of oxygen consumption by
organic and inorganic compounds in wastewater.
-
- CLARIFICATION:
- Any process or combination of processes whose major purpose
is reducing the concentration of suspended matter in a liquid phase.
-
- COAGULANT AID:
- Any chemical or substance used to assist coagulation.
-
- COAGULATION:
- The use of chemicals to cause small particles to agglomerate into
larger particles, thus making separation of solids from liquid
easier.
-
- COLLOIDS:
- Very finely divided particles that remain dispersed in a liquid phase for
long periods of time due to their electrical charge and small size.
-
-
CONTACT STABILIZATION:
- In contact stabilization, which is a modification of the conventional
activated sludge process, two (2) aeration tanks
are used. One tank is used for separate re-aeration of return sludge,
usually for at least four (4) hours, before it flows into the other
tank
where it is mixed with raw primary wastewater.
D
- DENITRIFICATION:
- A condition in which nitrite or nitrate ions are reduce to nitrogen gas.
The resulting bubbles often cause floating sludge in secondary clarifiers or
gravity thickeners.
-
- DIGESTER:
- A tank in which sludge is placed to allow decomposition by microorganisms.
-
-
DISSOLVED AIR FLOTATION (DAF) UNIT:
- A mechanical device which facilitates the separation of solids from the
liquid phase be use of super-saturated air
to generate floatation bubbles.
-
- DISSOLVED OXYGEN:
- Molecular oxygen dissolved in water or wastewater and is
usually abbreviates as DO.
E
- EFFLUENT:
- Wastewater or other liquid flowing from a tank, process or container.
-
- EQUALIZATION BASIN:
- A holding basin in which variations in flow or concentration are averaged.
F
- FACULTATIVE BACTERIA:
- Bacteria that can live under aerobic or anaerobic
conditions.
-
- FLOCCULATION:
- The gathering together of finer particles to form larger
particles.
G
- GRAS:
- GRAS means generally recognized as safe. It is the
designation given to substances that are considered safe for direct or
indirect additives to foods. For a substance to be considered GRAS it had to
meet certain criteria. There are two basic ways for a substance to be
designated as GRAS. The criteria for this process is given in detail in the
Code of Federal Regulations Title 21, Volume 3, Parts 170.30. The Federal
code is searchable from: http://www.access.gpo.gov/nara/cfr/cfr-retrieve.html#page1
H
I
- INFLUENT:
- Wastewater or other liquid flowing into a tank, container or
process.
J
- JAR TEST:
- A laboratory procedure for estimation of the amount of chemical that
will be needed to achieve selected water quality standards.
K
L
M
- MSDS
- Material Safety Data Sheet - an MSDS provide important
product information for proper handling, storage, shipping and other areas
that employees dealing with said product should know.
-
- MIXED LIQUOR:
- The mixing of activated sludge with raw wastewater and
return sludge in an aeration tank. Mixed liquor may also refer
to the contents of aerobic and anaerobic digesters.
-
-
MIXED LIQUOR SUSPENDED SOLIDS (MLLS):
- The suspended
solids in the mixed liquor of an aeration tank. Comprised of volatile
and non-volatile suspended solids.
-
- MIXED LIQUOR VOLATILE SUSPENDED SOLIDS (MLVSS):
- The organic or volatile
suspended solids in the mixed liquor of an aeration tank. Commonly
used to indicate viable bacteria content when compared to MLLS.
-
-
MOTILE:
- Organisms
that exhibit or are capable of movement.
N
- NSF
- NSF
is the only standards development and certification organization with over
50 years of dedicated service to public health safety and environmental
quality. The NSF Mark certifies a product as meeting rigorous public health
safety standards.
-
- NPDES PERMIT:
-
National Pollutant Discharge Elimination Discharge System
permit is the regulatory document that was designed to control all
discharges of pollutants from point sources into U.S. waterways.
-
-
NITRIFICATION
-
A
process in which bacteria change ammonia or organic
nitrogen in wastewater into form of oxidized nitrogen, usually
nitrate.
-
- NUTRIENTS
- Substances that are required for supporting living plants and organisms.
O
-
ORTHOPHOSPHATE
- Salt
or acid containing phosphorus as PO4.
-
- OXIDATION
- Oxidation
is the addition of oxygen, removal of hydrogen or the
removal of electrons from an element or compound.
P
-
Water intended for drinking, or general public consumption
or use.
-
-
- pH
- The
reciprocal of the logarithm of the hydrogen ion concentration.
-
POLYELECTROLYTE
- A
high molecular weight substance that is formed be either a natural or
synthetic process. Often called a “polymer”.
- POLYMER
- Natural
polymers may be of biological origin or derived from starch products, cellulose derivatives and
alginates. Synthetic polyelectrolyte
consist of simple substances that have been made into complex, high molecular weight substances.
-
-
PRIMARY TREATMENT
- The
first major and in some cases the only treatment
step taken in a wastewater treatment plant. Usually sedimentation.
Q
R
S
-
SEDIMENTATION
- The
process of deposition of suspended matter carried by
water, wastewater or other liquid by gravity.
-
-
SLUDGE VOLUME INDEX
(SVI)
- A test used to indicate the settling ability of activated sludge in the secondary clarifier.
-
-
SECONDARY TREATMENT
- A wastewater treatment process used to convert dissolved or suspended materials into a form more readily separated
from the water being treated.
-
- SEPTIC
- A
condition produced by anaerobic bacteria. If severe, the water turns black,
gives off a foul odor and contains little or no dissolved oxygen.
-
- SHOCK LOAD
- The
arrival at a process or plant of a waste that is toxic to organisms in sufficient quantity or strength to cause operational problems.
T
-
TERTIARY TREATMENT
-
A
process that removes specific wastes not generally removed by conventional treatment processes.
U
V
-
VOLATILE SOLIDS
- The
quantity of solids in water, wastewater or other liquids lost on ignition of the dry solids at 600oC.
W
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