Glossary of Terms for Onsite Wastewater Treatment and Dispersal
Below is a list of terms used throughout the field of onsite wastewater treatment and this site.
-
A
- Absorption:
- The process by which one substance is physically taken into and included
with another substance. [3]
- Acute toxicity:
- Exposure that will result in significant response shortly after exposure
(typically a response is observed within 48 or 96 hours). [1]
- Adsorption:
- The adhesion of molecules to the surface of solid bodies or liquids with
which they are in contact. [3]
- Advanced treatment:
- Removal of dissolved and suspended materials remaining after normal biological
treatment when required for water reuse or for the control of eutrophication
in receiving waters. [1]
- Aerobic:
- Growing in the presence of oxygen, as in aerobic bacteria or aerobic treatment.
[2]
- Aerobic treatment unit:
- A container of various configurations that provides for aerobic degradation
or decomposition of wastewater constituents by bringing the wastewater into
direct contact with air by some mechanical means. [4]
- Alternative system:
- An onsite sewage system other than a conventional gravity system or a conventional
pressure distribution system. Properly operated and maintained alternative
systems provide equivalent or enhanced treatment performance as compared to
conventional gravity systems. [4]
- Anaerobic:
- Growing in the absence of oxygen, as in anaerobic bacteria in a septic tank.
[2]
- Anoxic process:
- The process by which nitrate-nitrogen is converted biologically to nitrogen
gas in the absence of oxygen. The process is also known as anoxic denitrification.
[1]
- Approved:
- A written statement of acceptability, in terms of the requirements in local
and state regulations issued by the local health officer. [4]
- Approved list:
- A list of approved systems and products, developed by local health departments
which may contain the following: list of proprietary devices approved by the
department; list of specific systems meeting Treatment Standard 1 and Treatment
Standard 2; list of experimental systems approved by the department; and list
of septic tanks, pump chambers, and holding tanks approved by the department.
[4]
- Attached-growth processes:
- Biological treatment processes in whihc the microorganisms responsible for
the conversion of the organic matter or other constituents in the wastwater
to gases and cell tissue are attached to some inert medium, such as rocks,
slag, or specifically designed ceramic or plastic materials. Attached-growth
treatment processes are also known as fixed-film processes. [1]
-
index
B
- BADCT:
- Arizona regulatory terminology that means the best available demonstrated
control technology, process, operating method, or other alternative to achieve
the greatest degree of discharge reduction determined for a facility by the
ADEQ Director under A.R.S. § 49-243. [5]
- Baffles:
- Deflectors, vanes, guides, grids, gratings, or similar devices constructed
or placed in flowing water, wastewater, or slurry systems as a check or to
effect a more uniform distribution of velocities; absorb energy; divert, guide,
or agitate the liquids; and check eddies. [3]
- Ball valve:
- A simple non-return valve consisting of a ball resting on a cylindrical
seat within a fluid passageway. [3]
- Biochemical oxygen demand (BOD):
- A standard test that measures the strength of wastewater by determining
the quantity of oxygen that is naturally consumed by the wastewater under
standard conditions. Generally it is measured in mg/L. [2]
- Biological filter:
- A bed of sand, gravel, broken stone, or other medium through which wastewater
flows or trickles, which depends on biological action for effectiveness. [3]
- Biomat:
- The biological mat (biomat) is a black, jelly-like mat about one
to two inches thick, that forms at the gravel-soil interface at the bottom
and sidewalls of the drainfield trench. The biomat is composed of microorganisms
(and their byproducts) that anchor themselves to soil and rock particles,
and whose food is the organic matter in the septic tank effluent. Since the
biomat has a low permeability, it serves as a valve to slow down and control
the rate of flow out of the trench into the drainfield soil, and also serves
as a filter to provide effluent treatment. Also known as a clogging mat.[3]
- Blackwater:
- That portion of the wastewater stream that originates from toilets. It includes
feces, urine, and associated flush waters. [4]
index
C
- Cesspool:
- A lined or partially lined underground pit into which raw household wastewater
is discharge and from which the liquid seeps into the surrounding soil. Sometimes
called leaching cesspool. [3]
- Chemical oxygen demand (COD):
- A standard test that measures the amount of the organic matter in wastewater
that can be oxidized (burned up) by a very strong chemical oxidant. [2]
- Chronic toxicity:
- Exposure that will result in sublethal response over a long term, often
one-tenth of the life span or more. [1]
- Clarification:
- Any process or combination of processes, the primary purpose of which is
to reduce the concentration of suspended matter in a liquid. Term formerly
used as a synonym of settling or sedimentation. In recent years,
the latter terms are preferable when describing the settling process. [3]
- Cleanout:
- Any structure or device which is designed to provide access for the purpose
of removing deposited or accumulated materials. [3]
- Clogging mat:
- See biomat.
- Coliform:
- One type of bacteria. The presence of coliform-type bacteria is an indication
of possible pathogenic bacterial contamination. Fecal coliforms are
those coliforms found in the feces of various warm-blooded animals, whereas
the term coliform also includes other environmental sources. [2]
- Constituent:
- Individual components, elements, or biological entities such as suspended
solids or ammonia nitrogen. [1]
- Contaminants:
- Constituents added to the water supply through use. [1]
- Conventional gravity system:
- An onsite sewage system consisting of a septic tank and a subsurface soil
absorption system with gravity distribution of the effluent. [4]
- Conventional pressure distribution system:
- An onsite sewage system consisting of a septic tank and a subsurface soil
absorption system with pressure distribution of the effluent. [4]
- Creeping failure:
- A condition where the biomat becomes so intensely developed that no water
can flow through it eventually causing system malfunction. [2]]
index
D
- Daily flow rate:
- Arizona regulatory terminology that means the average daily flow calculated
for the month that has the highest total flow during the calendar year. [5]
- Decentralized wastewater management:
- Collection, treatment, and disposal/reuse of wastewater from individual
homes, clusters of homes, isolated communities, industries, or institutional
facilities, as well as from portions of existing communities at or near the
point of waste generation. [1]
-
- Denitrification:
- The anaerobic biological reduction of nitrate-nitrogen to nitrogen gas.
Also removal of total nitrogen from a system. [3]
- Design life:
- The estimated length of time befor the system will have to be replaced or
rehabilitated. [6]
- Detention Time:
- The period of time that a water or wastewater flow is retained in a basin,
tank, or reservoir for storage or completion of physical, chemical, or biological
reaction. [3]
- Direct reuse site:
- Arizona regulatory terminology that means an area where reclaimed water
is applied or impounded. [5]
- Disinfection:
- The process of destroying pathogenic organisms in water and wastewater.
[2]
- Dissolved Oxygen:
- The concentration of oxygen (normally a gas) dissolved in water. It is a
function of temperature and pressure. The colder the water, the more oxygen
it will hold. In general, fish require 5.0 mg/L in a stream. [2]
- Domestic Wastewater:
- Wastewater that is generated from sanitary fixtures and appliances, food
handling, etc. [2]
- Drain Pipes:
- A pipe or conduit that carries untreated runoff water to nearby waterways
to reduce flooding of pavements. Not to be confused with sewers which carry
wastewater. [2]
- Drywell:
- A well which is a bored, drilled, or driven shaft or hole whose depth is
greater than its width and is designed and constructed specifically for the
disposal of storm water. [5]
index
E
- Effluent:
- Wastewater, partially or completely treated, flowing out of a reservoir,
tank, treatment component, or disposal component. [4]
- Eutrophication:
- The process by which a waterbody becomes over-enriched with nutrients. While
this is a naturally-occurring process, it can be accelerated by human activities
and generally results in a less-diversified and less-desirable waterbody.
[2]
index
F
-
- Facultative processes:
- Biological treatment processes in which the organisms can function in the
presence or absence of molecular oxygen. [1]
- Failure:
- Inability of water to penetrate the soil. [6]
- Fecal coliform:
- Indicator bacteria common to the digestive systems of warm-blooded animal
that is cultured in standard tests to indicate contamination from sewage or
level of disinfection. Generally measured as colonies/100 mL. [2]
- Fixed-film processes:
- See attached-growth processes.
- Flocculate:
- To cause (soil) to form small lumps or masses. [3]
- Flow rate (or discharge or "Q"):
- Minimum design pumping rate required to deliver effluent in a timely fashion
to a gravity system and to pressurize a pressure manifold of low pressure
pipe laterals. [2]
- French drain:
- An underground passageway for water through the interstices among stones
placed loosely in a trench. [3]
index
G
- Grease interceptor (trap):
- In plumbing, a receptacle designed to collect and retain grease and fatty
substances normally found in kitchen or similar wastes. It is installed in
the drainage system between the kitchen or other point of production of the
waste and the building sewer. [3]
- Greywater:
- That portion of the wastewater stream that originates in sinks, tubs, showers,
laundry; i.e., all portions of the wastewater stream excluding toilet wastes.
[4]
index
H
- Hydraulic loading rate:
- An empirically-derived design and operating parameter that relates to ponding,
surface shearing rate, and hydraulic detention time. Usually repored in units
of volume of wastewater (including recycle) per unit cross-sectional area
per day.. [1]
index
I
- Industrial wastewater:
- Wastewater from industrial processes or contaminated with wastewater from
industrial processes. [2]
- Infiltration:
- (1) The flow or movement of water through the interstices of pores of soil
or other porous medium.[3] (2) Groundwater seeping
into a collection system. [2]
- Inflow:
- Direct rainflow, such as rooftop drains, into a collection system. [2]
- Influent:
- Wastewater, partially or completely treated, or in its natural state (raw
wastewater) that flows into a reservoir, tank, treatment component, or disposal
component. [4]
- Inorganic:
- The minerals, salts, etc. present in wastewater not attributed to carbon
molecules of the organic. Examples include iron, silver, lead, sodium. [2]
index
J
K
L
- Limiting factor:
- The condition that limits treatment capacity usually either groundwater
or bedrock. [6]
- Low pressure pipe (LPP):
- Lateral 1" - 2" pipe with small orifices (5/32" - 1/4") through which effluent
is\ distributed to trench under low pressure (2 to 5 feet). [2]
index
M
- Mastic:
- Any of various pasty materials used as protective coatings or cements. [3]
index
N
- Nitrification:
- The oxidation of ammonia-nitrogen to nitrate-nitrogen in wastewater by biological
or chemical reactions. [3]
-
- Nutrients:
- The minerals and other materials that provide food for living organisms.
Traditionally, nitrogen, phosphorous, and potassium are thought of as the
most important elemental nutrients for streams and lakes. [2]
index
O
- Onsite wastewater treatment facility (sewage system):
- An integrated arrangement of components for a residence, building, industrial
establishment, or other places not connected to a public sewer system which:
conveys, stores, treats, and/or provides subsurface soil treatment and disposal
on the property where it originates or upon adjacent or nearby property; and
includes piping, treatment devices, other accessories, and soil underlying
the disposal component of the initial and reserve areas. [4]
- Operational life:
- Arizona regulatory terminology that means the designed or planned useful
period during which a facility remains operational while continuing to be
subject to permit conditions, including closure requirements. Operational
life does not include post-closure activities. [5]
- Organic:
- The molecules, cells, etc. in wastewater from living organisms based on
elemental carbon. [2]
- Orifice:
- Discharge hole in low pressure lateral or pressure manifold. [2]
index
P
- Parameter:
- A measurable factor such as temperature. [1]
- Pathogens:
- Organisms that cause disease. Examples in wastewater include Salmonella,
Vibro Cholera, and Entamoeba histolytica. [2]
- Percolation:
- Seepage through a permeable material. [3]
- Permeable:
- Having pores or openings that permit liquids or gases to pass through. [3]
- pH:
- A measure of the acid or base quality of water that is the negative log
of the hydrogen ion concentration. The scale ranges from 1-14. A pH of 7.0
is neutral with 13.0 being very basic and 1.0 being very acidic. [2]
- Pressure manifold:
- Three inch to eight inch pipe with larger orifices (1/2" - 1") through which
effluent is distributed to gravity supply lines that in turn feed conventional
gravity trenches. [2]
- Pressure distribution:
- A system of small diameter pipes equally distributing effluent throughout
a trench or bed. [4]
- Primary treatment:
- Removal of a portion of the suspended solids and organic matter from the
wastewater. [1]
- Pump chamber:
- A tank or compartment following the septic tank which contains a pump, floats,
and volume for storage of effluent. Effluent is pumped from the pump chamber
to another pretreatment process or to the disposal component. In certain types
of pressure distribution systems, this may also be called a "surge tank."
If a siphon is used in lieu of a pump, this will be called a "siphon
chamber.". [4]]
index
Q
R
- Reserve area:
- An area of land approved for the installation of a conforming system and
dedicated for replacement of the onsite sewage system upon its failure. [4]
- Restrictive layer:
- A stratum impeding the vertical movement of water, air, and growth of plant
roots, such as hardpan, clay pan, fragipan, caliche, some compacted soils,
bedrock, and unstructured clay soils. [4] [4]
index
S
- Scum (cake):
- A layer of wastewater particles floating on the liquid surface in a septic
tank. [3]
- Secondary treatment:
- Removal of biodegradable organics and suspended solids. Disinfection is
also typically included in the definition of conventional secondary treatment.
[1]
- Septage:
- The semi-liquid material that is pumped out of septic (or interceptor) tanks,
consisting of liquid, scum, and sludge. [2]
- Septic tank:
- A water-tight pretreatment receptacle receiving the discharge of sewage
from a building sewer or sewers, designed and constructed to permit separation
of settleable and floating solids from the liquid and detention and anaerobic
digestion of the organic matter prior to discharge of the liquid. [4]
- Setback:
- Arizona regulatory terminology that means a minimum horizontal distance
maintained between a feature of a discharging facility and a potential point
of impact. [5]
- Settleable solids:
- Suspended solids, in mL/L, that will settle out of suspension within a specified
period of time. [1]
- Sewage:
- Untreated wastes from toilets, baths, sinks, lavatories, laundries, and
other plumbing fixtures in places of human habitation, employment, or recreation.
[5]
- Sewer:
- A pipe or conduit that carries wastewater. Not to be confused with drain
pipes which carry untreated runoff water to nearby waterways to reduce flooding
of pavements. [2]
- Soil absorption capacity:
- In subsurface effluent disposal, the ability of the soil to absorb water.
[3]
- Subsurface soil absorption system:
- A system of trenches of three feet or less in width, or beds between three
and ten feet in width, containing distribution pipe within a layer of clean
gravel designed and installed in original, undisturbed soil for the purpose
of receiving effluent and transmitting it into the soil. Also known as leach
fields, drainfields, and absorption fields. [4]
- Suspended-growth processes:
- Biological treatment processes in which the microorganisms responsible for
the conversion of the organic matter or other constituents in the wastewater
to gases and cell tissue are maintained in suspension within the liquid. [1]
index
T
- Tertiary treatment:
- Removal of residual suspended solids, usually by granular medium filtration.
Disinfection is also typically a part of tertiary treatment. Nutrient removal
is often included in this definition. [1]
- Total solids:
- The mineral, cells, etc. left in wastewater after evaporation of the water
fraction at 103°C. Usually measured in mg/L. [2]
- Total suspended solids:
- The mineral, cells, etc. in wastewater retained on a standard filter paper
after filtration followed by drying at 103°C. Usually measured in mg/L.
[2]
- Toxicity:
- The adverse effect which a biologically active substance has, at some concentration,
on a living entity. [3]
- Trace element:
- Any element in water or wastewater that, for reasons associated with natural
distribution, industrial uses, solubility, or other factors, is present at
very low concentrations. [3]
- Trap:
- (1) A device used to prevent a material flowing or carried through a conduit
from reversing its direction of flow or movement or from passing a given point.
(2) A device to prevent the escape of air from sewers through a plumbing fixture
or catch basin. [3]
- Treatment standard 1:
- A thirty-day average of less than 10 mg/L of biochemical oxygen demand (BOD),
10 mg/L of total suspended solids (TSS), and a thirty-day geometric mean of
less than 800 fecal coliform colonies per 100 mL. [4]
- Treatment standard 2:
- A thirty-day average of less than 10 mg/L of biochemical oxygen demand (BOD),
10 mg/L of total suspended solids (TSS), and a thirty-day geometric mean of
less than 800 fecal coliform colonies per 100 mL. [4]
- Total suspended solids (TSS):
- A measurement of the solids that either float on the surface of, or are
in suspension in, water or wastewater. A measure of wastewater strength often
used in conjunction with biochemical oxygen demand (BOD). [4]
- Typical sewage:
- Arizona regulatory terminology that means sewage in which the total suspended
solids (TSS) content does not exceed 430 mg/L, the five-day biochemical oxygen
demand (BOD) does not exceed 380 mg/L, and the content of fats, oils, and
greases (FOG) does not exceed 75 mg/L. [5]
index
U
V
- Vertical separation:
- The depth of unsaturated, original, undisturbed soil of Soil Types 1B-6
between the bottom of a disposal component and the highest seasonal water
table, a restrictive layer, or Soil Type 1A. [4
index
W
- Wastewater:
- The liquids generated from industrial processes, sanitary fixtures and appliances,
food handling, etc. [2]
- Wastewater reclamation:
- Processing of wastewater for reuse. [3]
- Waters of the United States:
- Federal regulatory terminology that means:
- All waters that are currently used, were used in the past, or may be
susceptible to use in interstate or foreign commerce, including all waters
that are subject to the ebb and flow of the tide;
- All interstate waters, including interstate wetlands;
- All other waters such as intrastate lakes, rivers, streams (including
intermittent streams), mudflats, sandflats, wetlands, sloughs, prairie
potholes, wet meadows, playa lakes, or natural ponds the use, degradation,
or destruction of which would affect or could affect interstate or foreign
commerce including any waters:
- That are or could be used by interstate or foreign travelers for
recreational or other purposes;
- From which fish or shellfish are or could be taken and sold in interstate
or foreign commerce; or
- That are used or could be used for industrial purposes by industries
in interstate commerce;
- All impoundments of waters defined as waters of the United States under
this definition;
- Tributaries of waters identified in subsections (1) through (4);
- The territorial sea; and
- Wetlands adjacent to waters (other than waters that are themselves wetlands)
identified in subsections (1) through (6). [5]
-
- X
index
Y
-
-
-
- Zero discharge:
- (1) Complete recycling of water. (2) Discharge of essentially pure water.
(3) Discharge of a treated effluent containing no substance at a concentration
higher than that found normally in the local environment. [3]
References definitions were adapted from
- Crites, R. and G. Tchobanoglous. 1998. Small and Decentralized Wastewater
Management Systems. Boston: McGraw-Hill Co., Inc.
- Hoover, M.T., T.A. Disy, M.A. Pfeiffer, N. Dudley, R.B. Mayer, and B. Buffington.
1996. North Carolina subsurface wastewater system operators training school
manual. Soil Science Department, College of Agriculture and Life Sciences,
North Carolina State University, Raleigh, NC and North Carolina Department
of Environment, Health, and Natural Resources, Raleigh, NC.
- Kahn, L., B. Allen, and J. Jones. 2000. The Septic System Owner's Manual.
Bolinas, CA: Shelter Publications .
- Trotta, P., J. Ramsey, and S. Hoban. 2000. The basics and fundamentals of
onsite wastewater treatment course. Flagstaff, AZ: Northern Arizona University.
- Arizona Department of Environmental Quality. Aquifer Protection Permits. R18-9-101.
January 1, 2001. Phoenix, AZ: ADEQ.
- Burks, B.D. and M.M. Minnis. 1994. Onsite Wastewater Treatment Systems.
Madison, WI: Hogarth House, Ltd.
