Browse Our Extended Glossary of Terms.

We have compiled an extensiive list of helpful remediation and scientific terms to assist clients and researchers. Use the alphabetic guide below and/or the scroll bar to find the term or terms desired.

Abiotic Factors
Non living; moisture, soil, nutrients, fire, wind, temperature, climate.

The taking in or soaking up of one substance into the body of another by molecular or chemical action (as tree roots absorb dissolved nutrients in the soil).

Absorption Field
A system of properly sized and constructed narrow trenches partially filled with a bed of washed gravel or crushed stone into which perforated or open joint pipe is placed. The discharge from the septic tank is distributed through these pipes into trenches and surrounding soil. While seepage pits normally require less land area to install, they should be used only where absorption fields are not suitable and well-water supplies are not endangered.

A substance that dissolves in water with the formation of hydrogen ions, contains hydrogen which may be replaced by metals to form salt, and/or is corrosive.

The capacity of water or wastewater to neutralize bases. Acidity is expressed in milligrams per liter of equivalent calcium carbonate. Acidity is not the same as pH.

Activated Sludge
Sludge particles produced in raw or settled wastewater (primary effluent) by the growth of organisms (including zoogleal bacteria) in aeration tanks in the presence of dissolved oxygen. The term “activated” comes from the fact that the particles are teeming with fungi, bacteria, and protozoa. Activated sludge is different from primary sludge in that the sludge particles contain many living organisms which can feed on the incoming wastewater.

The gathering of a gas, liquid, or dissolved substance on the surface or interface zone of another substance.

Adenosine diphosphate. See ATP.

The process of adding air to water. In wastewater treatment, air is added to freshen wastewater and to keep solids in suspension.

Aeration Tank
The tank where raw or settled wastewater is mixed with return sludge and aerated. This is the same as an aeration bay, aerator, or reactor.

An organism that requires free oxygen for growth.

Alkaline Substance
Chemical compounds in which the basic hydroxide ion (OH-) is united with a metallic ion, such as sodium hydroxide (NaOH) or potassium hydroxide (KOH). These substances impart alkalinity to water and are employed for neutralization of acids. Lime is the most commonly used alkaline material in wastewater treatment.

Astringent crystalline double sulfate of an alkali. K2SO4AL2 (SO4)3 24H2O. Used in the processing of pickles and as a flocking agent. Excess aluminum in the environment can be hazardous.

Ammonia Oxidation
Test drawn during manufacturing process to evaluate the ammonia oxidation rate for the nitrifiers.

Ambient Temperature
Temperature of the surroundings.

An organism that lives and reproduces in the absence of dissolved oxygen, instead deriving oxygen from the breakdown of complex substances.

Very dry. No water or dampness is present.

Anti Fouling
The process of removing the accumulation, or preventing its accumulation. In industrial processes bio-dispersants can be used to control biofouling.

Antibiotic Resistance
When antibiotics are incorrectly used (to treat bacteria that are not sensitive to the specific antibiotic or to treat viruses, which NEVER respond to antibiotics) and are not taken for the full term prescribed (usually from 5 to 21 days, depending on the specific antibiotic and disease being treated), surviving pathogenic organisms develop immunity to the antibiotic and pass it along to descendants and might choose to pass the trait along to unrelated bacteria via a process known as horizontal gene transfer.

A negatively charged ion in an electrolyte solution, attracted to the anode under the influence of a difference in electrical potential. Chloride is an anion.

API Separator
A facility developed by the Committee on Disposal or Refinery Wastes of the American Petroleum Institute for separation of oil from wastewater in a gravity differential and equipped with means for recovering the separated oil and removing sludge

The cultivation of fresh-water and marine species (the latter type is often referred to as mariculture). Aquacultural ventures occur worldwide. China grows macroalgae (seaweeds) and carp. Japan cultures a wide range of marine organisms, including yellowtail, sea bream, salmonids, tuna, penaeid shrimp, oysters, scallops, abalone, and algae. Russia concentrates on the culture of fish such as sturgeon, salmon, and carp. North America grows catfish, trout, salmon, oysters, and penaeid shrimp. Europe cultures flatfish, trout, oysters, mussels, and eels. Presently, plant aquaculture is almost exclusively restricted to Japan, China, and Korea, where the national diets include substantial amounts of macroalgae.

A genus of phyllopod Crustacea found in salt lakes and brines; brine shrimp.

Free from living germs of disease, fermentation or putrefaction.

To take in, similar to eating food.

Attached Growth Processes
Wastewater treatment processes in which the microorganisms and bacteria treating the wastes are attached to the media in the reactor. The wastes being treated flow over the media. Trickling filters, bio-towers, and RBCs are attached growth reactors. These reactors can be used for removal of BOD, nitrification, and denitrification.

Adenosine triphosphate. Chemical energy generated by substrate oxidations is conserved by formation of high-energy compounds such as adenosine diphosphate (ADP) and adenosine triphosphate (ATP) or compounds containing the thioester bond.

A unique form of metabolism found only in bacteria. Inorganic compounds (e.g., NH3, NO2-, S2, and Fe2+) are oxidized directly (without using sunlight) to yield energy. This metabolic mode also requires energy for CO2 reduction, like photosynthesis, but no lipid-mediated processes are involved. This metabolic mode has also been called chemotrophy, chemoautotrophy, or chemolithotrophy.

Advanced Waste Treatment – any process of water renovation that upgrades treated wastewater to meet reuse requirements.

Living organisms, microscopic in size, which usually consist of a single cell. Most bacteria use organic matter for their food and produce waste products as a result of their life processes.

Bacterial Photosynthesis
A light-dependent, anaerobic mode of metabolism. Carbon dioxide is reduced to glucose, which is used for both biosynthesis and energy production. Depending on the hydrogen source used to reduce CO2, both photolithotrophic and photoorganotrophic reactions exist in bacteria.

A substance which dissociates (separates) in aqueous solution to yield hydroxyl ions, or one containing hydroxyl ions (OH-) which reacts with an acid to form a salt or which may react with metal to form a precipitate.

Batch Process
A treatment process in which a tank or reactor is filled, the wastewater (or solution) is treated or a chemical solution is prepared and the tank is emptied. The tank may then be filled and the process repeated. Batch processes are also used to cleanse, stabilize or condition chemical solutions for use in industrial manufacturing and treatment processes.

Bench Scale Analysis
Also known as: “bench test”. A method of studying different ways of treating wastewater and solids on a small scale in a laboratory.
Benzene An aromatic hydrocarbon which is a colorless, volatile, flammable liquid. Benzene is obtained chiefly from coal tar and is used as a solvent for resins and fats in dye manufacture.

Binary Fission
During binary fission, a single cell divides transversely to form two new cells called daughter cells. Both daughter cells contain an exact copy of the genetic information contained in the parent cell.
Biocatalysis Chemical reactions mediated by biological systems (microbial communities, whole organisms or cells, cell-free extracts, or purified enzymes aka catalytic proteins).

Biotic Potential
All the factors that contribute to a species increasing its number. Reproduction, migration, adaptation etc.

Biochemical Oxygen Demand – the rate at which microorganisms use the oxygen in water or wastewater while stabilizing decomposable organic matter under aerobic conditions. In decomposition, organic matter serves as food for the bacteria and energy results from this oxidation.

BOD Test
A procedure that measures the rate of oxygen use under controlled conditions of time and temperature. Standard test conditions include dark incubation at 20oC for a specified time (usually 5 days).

Biodegradable Organic matter that can be broken down by bacteria to more stable forms which will not create a nuisance or give off foul odors.

A slime layer which naturally develops when bacteria attach to an inert support that is made of a material such as stone, metal, or wood. There are also non-filamentous bacteria that will produce an extracellular polysaccharide that acts as a natural glue to immobilize the cells. In nature, nonfilament-forming microorganisms will stick to the biofilm surface, locating within an area of the biofilm that provides an optimal growth environment (i.e., pH, dissolved oxygen, nutrients). Since nutrients tend to concentrate on solid surfaces, a microorganism saves energy through cell adhesion to a solid surface rather than by growing unattached and obtaining nutrients randomly from the medium. Pseudomonas and Nitrosomonas strains are especially well known for their ability to form a strong biofilm.
Bioflocculation The clumping together of fine, dispersed organic particles by the action of certain bacteria and algae.

A mass or clump of living organisms feeding on the wastes in wastewater, dead organisms and other debris.

A new discipline that studies nature’s best ideas and then imitates these designs and processes to solve human problems. Biomimicry (from bios, meaning life, and mimesis, meaning to imitate) is a design discipline that seeks sustainable solutions by emulating nature’s time-tested patterns and strategies, e.g., a solar cell inspired by a leaf.(borrowed from Janine Menyus – The Biomimicry Institute)

The deliberate alteration of an ecosystem by adding or removing species, especially predators

The use of biological agents, such as bacteria or plants, to remove or neutralize contaminants, as in polluted soil or water.

Bioremediation is the use of organisms to break down and thereby detoxify dangerous chemicals in the environment. Plants and microorganisms are used as bioremediators. The technology can take advantage of a natural metabolic pathway or genetically modify an organism to have a particular toxic “appetite.”

Any process that increases the rates of biological degradation, usually by the addition of nutrients, oxygen, or other electron donors and acceptors so as to increase the number of indigenous microorganisms available for degradation of contaminants.

An attached culture system. A tower filled with a media similar to rachet or plastic rings in which air and water are forced up a counterflow movement in the tower.

The clogging of the filtering medium of a microscreen or a vacuum filter when the holes or spaces in the media become sealed off due to a buildup of grease or the material being filtered.

A solution or liquid whose chemical makeup neutralizes acids or bases without a great change in pH.

Bulking Sludge
Clouds of billowing sludge that occur throughout secondary clarifiers and sludge thickeners when sludge becomes too light and will not settle properly. In the activated sludge process, bulking is usually caused by filamentous bacteria. This condition can be mediated by applying Nu-Bind and Clear-Flo 7015 to the system.
Cation exchange capacity The ability of a soil or other solid to exchange cations (positive ions such as calcium) with a liquid.

Cess Pools
This system is similar to a septic tank in performance. Sewage water usually seeps through the open bottom and portholes in the sides of the walls. These can also clog up with overuse and the introduction of detergents and other material which slow up the bacterial action.

Viable micro-organisms (bacteria, yeasts & mould) capable of growth under the prescribed conditions (medium, atmosphere, time and temperature) develop into visible colonies (colony forming units) which are counted. The term colony forming unit (CFU) is used because a colony may result from a single micro-organism or from a clump / cluster of micro-organisms.

An organism that obtains its energy from the oxidation of chemical compounds and uses only organic compounds as a source of carbon, e.g. nitrifiers.

An organism that obtains its energy from the oxidation of chemical compounds.

Chemical Precipitation
Precipitation induced by addition of chemicals; the process of softening water by the addition of lime and soda ash as the precipitants.

Compounds formed by the reaction of hypochlorous acid (or aqueous chlorine) with ammonia.

The application of chlorine to water or wastewater, generally for the purpose of disinfection, but frequently for accomplishing other biological or chemical results.

A class of protozoans distinguished by short hairs on all or part of their bodies.

Citric Acid
Derived from citrus fruit or by the fermentation of crude sugar, also used as antioxidant, sequestrant, dispersing agent. Helps adjust pH. No toxicity in diluted amounts.

Chemical oxygen demand – the amount of oxygen in mg/l required to oxidize both organic and oxidizable inorganic compounds.

A process in which suspended material is removed from wastewater. This may be accomplished by sedimentation, with or without chemicals, or filtration.

Settling tank, sedimentation basin. A tank or basin in which wastewater is held for a period of time, during which the heavier solids settle to the bottom and the lighter material will float to the water surface.

Chemicals which cause very fine particles to clump (floc) together into larger particles. This makes it easier to separate the solids from the water by settling, skimming, draining, or filtering.
Coliform bacteria Non-pathogenic microbes found in fecal matter that indicate the presence of water pollution; are thereby a guide to the suitability for potable use.

Very small, finely divided solids (particles that do not dissolve) that remain dispersed in a liquid for a long time due to their small size and electrical charge.

Combined Available Chlorine
The concentration of chlorine which is combined with ammonia (NH3) as chloramine or as other chloro derivatives, yet is still available to oxidize organic matter.

Combined Sewer
A sewer designed to carry both sanitary wastewaters and storm or surface-water runoff.

When two organisms coexist, with one organism deriving food or other benefits from another, without causing harm to the other organism. Often this relationship offers two-way benefits. For a more powerful version of this co-operation see synergism.

A natural consortium of commensal bacteria residing in saliva and the digestive system of fish, crustaceans and mammals, including humans, are necessary for proper digestion of foods into simple water-soluble compounds that can easily pass through intestinal walls to feed the host’s body.

A natural consortium of commensal bacteria will take up residence in the skin and coat of mammals, reducing objectionable odors from sweat and excess production of natural oils, meant to lubricate and protect the skin from the environment, when disinfectants are avoided in soaps, shampoos and skin care products. These commensal bacteria will try to protect their natural home by mechanically preventing invasion by pathogenic (disease-causing fungi and bacteria). Many natural commensal bacteria are exploited by pharmaceutical companies to produce antibiotics, used to cure some of the worst pathogenic organisms, but incorrect use and overuse of antibiotics is leading some pathogenic organisms to develop resistance to the most commonly used antibiotics. Natural commensal bacteria will produce a cocktail of antibiotics or will vary the antibiotics they produce to discourage pathogens they encounter from developing resistance.

Comminution Shredding
A mechanical treatment process which cuts large pieces of waste into smaller pieces so that they won’t plug pipes or damage equipment.

Contact Stabilization
Contact stabilization is a modification of the conventional activated sludge process. In contact stabilization, two aeration tanks are used. One tank is for separate reaeration of the return sludge for at least four hours before it is permitted to flow into the other aeration tank to be mixed with the primary effluent requiring treatment.

Conventional Treatment
The preliminary treatment, sedimentation, flotation, trickling filter, rotating biological contactor, activated sludge and chlorination of wastewater.

Changing from one substance to another. As food matter is changed to cell growth or to carbon dioxide.

Cell residence time – the amount of time in days that an average “bug” remains in the process. Also termed “sludge age”.

Dissolved air flotation – one of many designs for waste treatment.

Declining Growth
A growth phase in which the availability of food begins to limit cell growth.
Degradation A growth phase in which the availability of food begins to limit cell growth.

An anaerobic biological reduction of nitrate nitrogen to nitrogen gas, the removal of total nitrogen from a system, and/or an anaerobic process that occurs when nitrite ions are reduced to nitrogen gas and bubbles are formed as a result of this process. The bubbles attach to the biological floc in the activated sludge process and float the floc to the surface of the secondary clarifiers. This condition is often the cause of rising sludge observed in secondary clarifiers or gravity thickeners. (See Nitrification)

Dead plant and animal matter, usually consumed by bacteria, but some remains.

Dew Point
The temperature to which air with a given quantity of water vapor must be cooled to cause condensation of the vapor in the air.

D/I Unit
Deionizing unit frequently used to maintain water quality in aquariums. Advantages: does not waste water like the R/O unit, is designed to be hooked up to either a faucet or household piping system, the anion & cation resins can be regenerated (with another expensive unit) indefinitely, and these systems allow a larger water flow (up to 2,000 gallons a day), than an R/O system, but cost dramatically more too.

Diatomaceous Earth
A fine, siliceous (made of silica) “earth” composed mainly of the skeletal remains of diatoms (single cell microscopic algae with rigid internal structure consisting mainly of silica). Tests prove that DE leaches unacceptable amounts of silicate into the water for fish health. If used as a filter substance, a silicone removing resin should be employed afterwards.

Diffused Air Aeration
A diffused air activated sludge plant takes air, compresses it, and then discharges the air below the water surface of the aerator through some type of air diffusion device.

A tank in which sludge is placed to allow decomposition by microorganisms. Digestion may occur under anaerobic (most common) or aerobic conditions.

The process designed to kill most microorganisms in wastewater, including essentially all pathogenic (disease-causing) bacteria. There are several ways to disinfect, with chlorine being the most frequently used in water and wastewater treatment plants.

Distribution Box
Serves to distribute the flow from the septic tank evenly to the absorption field or seepage pits. It is important that each trench or pit receive an equal amount of flow. This prevents overloading of one part of the system.
Dissolved solids Chemical substances either organic or inorganic that are dissolved in a waste stream and constitute the residue when a sample is evaporated to dryness.

The rotating mechanism that distributes the wastewater evenly over the surface of a trickling filter or other process unit.

DO Dissolved Oxygen
A measure of the oxygen dissolved in water expressed in milligrams per liter.

Dissolved Oxygen Uptake Ratio, reported as mg DO/L/hour, a test that is used to measure how much oxygen is being consumed by the microbes in a wastewater treatment plant, to assure that the biomass is receiving sufficient dissolved oxygen.

The study of all aspects of how organisms interact with each other and/or their environment.

Groupings of various organisms interacting with each other and their environment.

Escherichia coli – one of the non-pathogenic coliform organisms used to indicate the presence of pathogenic bacteria in water.

Wastewater or other liquid – raw (untreated), partially or completely treated – flowing from a reservoir, basin, treatment process, or treatment plant.

Energy grade line – a line that represents the elevation of energy head in feet of water flowing in a pipe, conduit, or channel.

Electrolytic Process
A process that causes the decomposition of a chemical compound by the use of electricity.

A liquid mixture of two or more liquid substances not normally dissolved in one another, one liquid held in suspension in the other.

Endogenous Respiration
A reduced level of respiration (breathing) in which organisms break down compounds within their own cells to produce the oxygen they need.

Of intestinal origin, especially applied to wastes or bacteria.

Organic substances (proteins) produced by living organisms and act as catalysts to speed up chemical changes.

Environmental Resistance
All biotic and abiotic factors combining to limit explosion.

Equalizing Basin
A holding basin in which variations in flow and composition of liquid are averaged. Such basins are used to provide a flow of reasonably uniform volume and composition to a treatment unit. Also called a balancing reservoir.

Bodies of water which are located at the lower end of a river and are subject to tidal fluctuations.

The kingdom that describes ALL organisms (plants, fungi, animals, fish, birds, etc.) that have an organized nucleus surrounded by a nuclear membrane. The other major kingdom is the Procaryotes (containing only the primitive bacteria and Archae)

Bodies of water which are located at the lower end of a river and are subject to tidal fluctuations.

Facultative Anaerobe
A bacterium capable of growing under aerobic conditions or anaerobic conditions in the presence of an inorganic ion i.e. SO4, NO3.

Facultative Pond
The most common type of pond in current use. The upper portion (supernatant) is aerobic, while the bottom layer is anaerobic. Algae supply most of the oxygen to the supernatant.

Fatty Acid Methyl Ester, a means of identifying bacteria by analysis of the fatty acids in their cells. This is often done as an initial screening until a company is sure that a bacterial strain is one they wish to use commercially, and then 16S rRNA identification may be completed for a more definite identification and fingerprint of the strain, to keep competitors from copying that strain.
Fatty acids

A type of heterotrophic metabolism in which an organic compound rather than oxygen is the terminal electron (or hydrogen) acceptor. Less energy is generated from this incomplete form of glucose oxidation than is generated by respiration, but the process supports anaerobic growth.

Filamentous Organisms
Organisms that grow in a thread or filamentous form. Common types are Thiothrix, Actinomycetes, and Cyanobacteria (aka blue-green algae). This is a common cause of sludge bulking in the activated sludge process. Variously known as “pond scum”, “blue-green algae”, or “moss”, when it appears in a pond/lake, and confused with algae. Cyanobacteria form a symbiotic relationship with some varieties of algae, making the combination very difficult to combat in lakes and ponds. Filamentous organisms and Actinomycetes will naturally stick to solid surfaces. Common types of Cyanobacteria are: Oscillatoria, Anabaena, and Synechococcus. Other filament formers include: Spirogyra, Cladophora, Rhizoclonium, Mougeotia, Zygnema and Hydrodictyon. Nocardia is another filament former, which causes foaming and interferes with flocculation in a waste treatment plant.

Filter Aid
A chemical (usually a polymer) added to water to help remove fine colloidal suspended solids.

Floating Matter
Matter which passes through a 2000 micron sieve and separates by flotation for an hour.

Clumps of bacteria and particulate impurities or coagulants that have come together and formed a cluster. Found in aeration tanks and secondary clarifiers.

The process of forming floc particles when a chemical coagulant or flocculent such as alum or ferric chloride is added to the wastewater.

Food – represents BOD in the F/M ratio. Expressed in pounds

Fats, Oils and Greases. A measure of the non-petroleum based fats in waste treatment.

A ratio of the amount of food to the amount of organisms. Used to control an activated sludge process.

Flow Equalization System

A device or tank designed to hold back or store a portion of peak flows for release during low-flow periods.

Food Chain
Very simple pathway of nutrient flow. Ex. Carnivore > herbivore > plant.

The conversion of soluble and suspended materials into gas during anaerobic decomposition. In clarifiers the resulting gas bubbles can become attached to the settled sludge and cause large clumps of sludge to rise and float on the water surface. In anaerobic sludge digesters, this gas is collected for fuel or disposed of using a waste gas burner.

Generation Time
The time required for a given population to double in size. This time can be as short as 20 minutes or as long as a week.

Genetic Engineering
Scientists isolate a strand of DNA responsible for specific desired talents, but other undesirable traits, such as being slow-growing, finicky, and delicate or belonging to a pathogenic organism, make the source strain unsuitable for large-scale commercial growth to produce desired raw enzymes or end product. This isolated strand of desired DNA is often coupled with a gene for resistance to a specific antibiotic that is not native to a selected, safe, fast-growing, robust production strain so that exposing the genetically engineered cell to high levels of the antibiotic will kill off ALL clone offspring cells that did not incorporate the desired plasmid.

The USEPA FIFRA regulations PROHIBIT the uncontrolled release of genetically engineered organisms into the environment, to reduce the risk of unstable, engineered strains passing antibiotic resistance, immunity to chlorine bleach, survival of autoclaving or radiation exposure, etc. to unrelated species in the environment, potentially reducing our ability to effectively treat extremely dangerous pathogenic organisms, via horizontal gene transfer to Bacillus anthracis, Corynebacterium diptheriae, Streptococcus pyogenes, Clostridium botulinum, Clostridium tetanai, Legionella pneumoniae etc. , increasing the spread of Anthrax, Diptheria, Flesh-eating disease, Rheumatic fever, Botulism and Tetanus, Legionnaire’s Disease, the diseases caused by the species named above.

Glyoxylate Cycle
A modification of the Krebs cycle, which occurs in some bacteria. Acetyl coenzyme A is generated directly from oxidation of fatty acids or other lipid compounds.

Gram Positive
Bacterial cells which retain the crystal violet stain during a staining procedure. Most strains of bacilli are gram positive.

Gram Negative
Bacteria cells which lose the crystal violet during the decolorizing step and are then colored by the counter stain. Pseudomonas and Thiobacillus are examples of gram negative strains.

The heavy material present in wastewater, such as sand coffee grounds, eggshells, gravel and cinders.

Halophilic or Halotolerant
Bacteria which thrive in a highly salt environment, up to 25% NaCl.
Headworks The facilities where wastewater enters a wastewater treatment plant. The headworks may consist of bar screens, comminutors, a wet well and pumps.


Any chemical used to destroy or inhibit plant growth, especially of weeds or other undesirable vegetation. There are well over a hundred chemicals in common usage as herbicides. Many of these are available in several formulations or under several trade names. The variety of materials are conveniently classified according to the properties of the active ingredient as either selective or nonselective. Selective herbicides are those that kill some members of a plant population with little or no injury to others. Nonselective herbicides are those that kill all vegetation to which they are applied. Further subclassification is by method of application, such as preemergence (soil-applied before plant emergence) or postemergence (applied to plant foliage). Additional terminology sometimes applied to describe the mobility of post-emergence herbicides in the treated plant is contact (nonmobile) or translocated (mobile—that is, killing plants by systemic action).

A microorganism which uses organic matter for energy and growth.

Hours of Retention Time.

Horizontal Gene Transfer
The process by which bacteria and Archaea transfer genes to other bacteria or Archaea, especially obvious when a sudden environmental change forces resident bacteria or Archaea to seek a faster method of evolution than will occur slowly due to mutations of native DNA. Methods used include:

Conjugation – One cell binds to another cell, often unrelated, opening a connection through which it can pass a strand of DNA, copied from its primary DNA, into a separate contained packet of DNA, called a plasmid, to the recipient cell, without risking spilling cell contents from either donor or recipient cell into the environment. Conjugation is often a two-way transfer that enhances survival of both participants. If bacteria develop antibiotic resistance due to improper application of antibiotics (incorrect selection of treatment antibiotic, insufficient dosage to kill ALL bacteria exposed to the antibiotic), escaping bacteria may choose to pass antibiotic resistance along in plasmids to other bacteria they encounter in their environment (whether they normally live in hospitals, sewage systems, lakes, ponds, rivers or turf that is grazed by livestock.
DNA scavenging – One cell samples DNA strands strewn about during cell wall breakdown following death of bacterial cells that were intolerant of primary environmental conditions (temperature, pH, salinity, available food sources, antibiotics produced by native bacteria to keep them dominant, etc.), sometimes delivering beneficial enzyme pathways to the resident species. When horizontal gene transfer happens naturally in the environment, huge leaps in adaptation can occur, creating new species very distinct from parental strains.

House Sewer
The pipeline connecting the house and drain and the septic tank.

The dark organic material in soils, produced by the decomposition of soils. The matter that remains after the bulk of detritus has been consumed (leaves, roots). Humus mixes with top layers of soil (rock particles), supplies some of the nutrients needed by plants -increases acidity of soil; inorganic nutrients more soluble under acidic conditions, become more available, e.g. wheat grows best at pH 5.5-7.0. Humus modifies soil texture, creates loose, crumbly texture that allows water to soak in and nutrients retained; permits air to be incorporated into soil.
Hydraulic loading Hydraulic loading refers to the flows (MGD or m3/day) to a treatment plant or treatment process.

Any of a class of organic compounds composed only of carbon and hydrogen. The carbon atoms form the framework, and the hydrogen atoms attach to them. Hydrocarbons, the principal constituents of petroleum and natural gas, serve as fuels, lubricants, and raw materials for production of plastics, fibres, rubbers, solvents, explosives, and industrial chemicals. All burn to carbon dioxide and water with enough oxygen or to carbon monoxide without it. The two major categories are aliphatic, with the carbon atoms in straight or branched chains or in nonaromatic rings, and aromatic (see aromatic compound). Aliphatic compounds may be saturated (paraffins) or, if any carbon atoms are joined by double or triple bonds, unsaturated (e.g., olefins, alkenes, alkynes). All but the simplest hydrocarbons have isomers (see isomerism). Ethylene, methane, acetylene, benzene, toluene, and naphthalene are hydrocarbons.

Hydrogen Sulfide Gas
Hydrogen sulfide is a gas with a rotten egg odor. This gas is produced under anaerobic conditions. Hydrogen sulfide is particularly dangerous because it dulls your sense of smell so that you don’t notice it after you have been around it for a while and because the odor is not noticeable in high concentrations. The gas is very poisonous to your respiratory system, explosive, flammable, and colorless.

The process in which carbohydrates and starches are simplified into organic soluble organics, usually by facultative anaerobes.

Hydroponics is a method of growing plants in nutrient-rich water instead of soil. People have grown plants using hydroponics for about 50 years. This method is useful in places that have poor soil or for producing special plants for research. Growing conditions can be more closely controlled with hydroponics than out in the field: crops are not bothered by weeds or insects in their protected, watery environments, and their water and mineral needs are perfectly met in the large tanks in which they grow. Without soil, plants can also be grown closer together. One problem with hydroponics, though, is that plants often have trouble supporting themselves when their roots aren’t in soil, which can keep them from reaching full growth. Sometimes the roots of hydroponic plants are put in sand or gravel to fix the problem, or the plants are supported by wires. In the future, if people live in space stations-or on other planets-they will need to use hydroponics to raise food and to recycle carbon dioxide and oxygen.

Absorbing or attracting moisture from the air.

The conversion of dewatered wastewater solids by combustion (burning) to ash, carbon dioxide, and water vapor.

The seepage of groundwater into a sewer system, including service connections. Seepage frequently occurs through defective or cracked pipes, pipe joints, connections or manhole walls.

The liquid – raw (untreated) or partially treated – flowing into a reservoir, basin, treatment process or treatment plant.

To introduce a seed culture into a system.
Inorganic waste Waste material such as sand, salt, iron, calcium, and other mineral materials which are only slightly affected by the action of organisms. Inorganic wastes are chemical substances of mineral origin; whereas organic wastes are chemical substances usually of animal or plant origin.

The common boundary layer between two substances such as between water and a solid (metal) or between water and a gas (air) or between a liquid (water) and another liquid (oil).

Within same species; Elk vs. Elk

Between two different species, such as tomato and weeds.

The process of adding electrons to, or removing electrons from, atoms or molecules, thereby creating ions. High temperatures, electrical discharges, and nuclear radiation can cause ionization.

Kick Net
500 micron white mesh net is designed to meet the requirements of groups performing USEPA Rapid Bioassessment Protocols for Benthic Invertebrates. (Benthic = bottom dwelling)

Krebs Cycle
The oxidative process in respiration by which pyruvate (via acetyl coenzyme A) is completely decarboxylated to CO2. The pathway yields 15 moles of ATP (150,000 calories).

A complex polymer that occurs in woody material of higher plants. It is highly resistant to chemical and enzymatic degradation. Lignin is composed of various intermolecular linkages between phenylpropanes and guaiacyl, syringyl, p-hydroxyphenyl, and biphenyl nuclei. Analysis of the metabolic pathway has shown that the dimeric lignin compounds are degraded to protocatechuate or 3OMGA (3-O-methylgallic acid) and that these compounds are cleaved by protocatechuate 4,5-dioxygenase encoded by ligAB. Among the dimeric lignin compounds, the degradation of ß-aryl ether and the biphenyl structure is the most important, because ß-aryl ether is most abundant in lignin (50%) and the biphenyl structure is so stable that its decomposition is rate-limiting in lignin degradation. Sphingomonas paucimobilis is able to degrade a wide variety of dimeric lignin compounds, including ß-aryl ether, biphenyl, and diarylpropane.

The conversion of large solid particles of sludge into very fine particles which either dissolve or remain suspended in wastewater.

Log Growth
A growth phase in which cell production is maximum.

A disintegration or breakdown of cells which releases organic matter.

Lyophilization, Lyophilize
Freeze-drying, (sometimes spelled incorrectly as liophilization).

MacConkey Streak
Laboratory test for the presence of gram negative bacteria. We use this test to detect contamination of Bacillus products such as CF 1000, 1002, 4002 and some of the Enz-Odor® products.

An element required in large proportion by plants and other life forms for survival and growth. Macronutrients include Nitrogen (N), Potassium (K), and Phosphorous (P).

Masking Agent
Substance used to cover up or disguise unpleasant odors. Liquid masking agents are dripped into wastewater, sprayed into the air, or evaporated (using heat) with the unpleasant fumes or odors and then discharged into the air by blowers to make an undesirable odor less noticeable.

M Microorganisms
Small organisms which require a microscope to be seen. M represents the SS in the mixed liquor and is part of the F/M ratio.

Mean Cell Retention Time – days. An expression of the average time that a microorganism will spend in an activated sludge process.

Mechanical Aeration
The use of machinery to mix air and water so that oxygen can be absorbed into the water. Some examples are paddle wheels, mixers, rotating brushes to agitate the surface of an aeration tank; pumps to create fountains; and pumps to discharge water down a series of steps forming falls or cascades.

The material in the trickling filter on which slime accumulates and organisms grow. As settled wastewater trickles over the media, organisms in the slime remove certain types of wastes thereby partially treating the wastewater. Also the material in a rotating biological contactor (RBC) or in a gravity or pressure filter.

Methyl ethyl ketone.

Compounds containing sulfur which have an extremely offensive skunk-like odor. Also sometimes described as smelling like garlic or onions.

Mesophilic Bacteria
A group of bacteria that grow and thrive in a moderate temperature range between 68 F (20oC) and 113 F (45oC).

All of the processes or chemical changes in an organism or a single cell by which food is built up (anabolism) into living protoplasm and by which protoplasm is broken down (catabolism) into simpler compounds with the exchange of energy.

Million gallons daily – refers to the flow through a waste treatment plant.

Milligrams per liter = ppm (parts per million) – expresses a measure of the concentration by weight of a substance per unit volume.

A unit of length. One millionth of a meter or one thousandth of a millimeter. One micron equals 0.00004 of an inch.

An element required by plants and bacteria, in proportionately smaller amounts, for survival and growth. Micronutrients include: Iron (Fe), Manganese (MN), Zinc (Zn), Boron (B), and Molybdenum (Mo).

Methyl Isobutyl Ketone.

The name coined by a resident of Milwaukee, Wisconsin for “sewage sludge”, so he could scam people into buying sludge instead of paying to dispose of it! When this ingredient is listed in a septic product, you can be assured that the product is fraudulent! You don’t use sludge to get rid of sludge!

The smallest division of a compound that still retains or exhibits all the properties of the substance.

Aquaculture in which one species is grown.

Motile organisms exhibit or are capable of movement.

Mixed Liquor – the combination of raw influent and returned activated sludge. (no, not mixed drinks for human consumption)

Mixed Liquor Suspended Solids – The volume of suspended solids (see SS) in the mixed liquor (see ML) of an aeration tank.

Mixed Liquor Volatile Suspended Solids – the volume of organic solids that can evaporate at relatively low temperatures (550oC) from the mixed liquor of an aeration tank. This volatile portion is used as a measure or indication of microorganisms present. Volatile substances can also be partially removed by air stripping.

MPN Index
Most Probable Number of coliform-group organisms per unit volume of sample water. Expressed as a density or population of organisms per 100 mL of sample water

Abbreviation for either Multiple Antibiotic Resistant Staph. or Methicillyn Antibiotic Resistant Staph. We do not use Staph. in our products and we test to verify that with QC8. We also test the strains we select with common antibiotics and refuse to use any strains that are resistant to the most commonly used antibiotics, despite other favorable traits, since we do not want to risk responsibility for passing negative traits to pathogens found in nature.

Material Safety Data Sheet – a document that provides pertinent information and a profile of a particular hazardous substance or mixture. An MSDS is normally developed by the manufacturer or formulator of the hazardous substance or mixture. The MSDS is required to be made available to employees and operators whenever there is the likelihood of the hazardous substance or mixture being introduced into the workplace. Some manufacturers prepare MSDS for products that are NOT considered to be hazardous to show that the product or substance is NOT hazardous.

Two species living together in a relationship in which both benefit from the association.

Ammonia nitrogen.

Hospital-acquired infections. Specific species are most well-known for Nosocomial transmission and rarely pass from human to human within their native environments. Since many people are taken to hospitals for physical trauma (car crash, surgery needed, etc.) or disease (including cancer, viral or bacterial infections, malfunctioning organs needing transplant), their naturally-protective immune systems may be damaged by the injury. disease or even by treatment (radiation, chemotherapy, drugs to cancel transplant resistance, etc.), improving the ability of any bacteria present to spread from patient to patient and among hospital staff, themselves. Nosocomial strains spread in hospital environments by developing increased virulence factors that enhance spread of infection. Whether acquired by mutation or “horizontal gene transfer”, every Nosocomial infection seeks to add antibiotic resistance genes that enable them to escape treatment with antibiotics that used to rapidly rescue hospital patients by killing them off. At this time, the most common Nosocomial bacteria belong to the following species: Serratia marcescans, Acinetobacter baumanii, Alcaligenes faecalis, Pseudomonas aeruginosa, Legionella pneumophila and the one infective strain of Escherichia coli, strain 0157. Although rarely causing serious infections, most health authorities also monitor the import and transfer of Stenotrophomonas maltophila, because this species is known for having more genes for antibiotic-resistance than any other known species and is suspected of passing along these genes via horizontal gene transfer, a terrifying prospect.

NPDES Permit
National Pollutant Discharge Elimination System permit is the regulatory agency document issued by either a federal or state agency which is designated to control all discharges of pollutants from point sources into U.S. waterways. NPDES permits regulate discharges into navigable waters from all point sources of pollution, including industries, municipal wastewater treatment plants, sanitary landfills, large agricultural feed lots and return irrigation flows.

An aerobic process in which bacteria change the ammonia and organic nitrogen in wastewater into oxidized nitrogen (usually nitrate). The second-stage BOD is sometimes referred to as the “nitrification stage” (first-stage BOD is called the “carbonaceous stage”).

Nitrifying Bacteria
Bacteria that change the ammonia and organic nitrogen in wastewater into oxidized nitrogen (usually nitrate).

Nitrogen Fixation
Conversion of atmospheric nitrogen into organic nitrogen compounds available to green plants; a process that can be carried out only by certain strains of soil bacteria. None of these are present in our products.

Nucleic Acid
An organic acid consisting of joined nucleotide complexes; the principal types are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

Substances which are required to support living plants and organisms. Major nutrients are carbon, hydrogen, oxygen, sulfur, nitrogen and phosphorus. Nitrogen and phosphorus are difficult to remove from wastewater by conventional treatment processes because they are water soluble and tend to recycle.

Obligate Aerobe
Bacteria which require the presence of oxygen, such as Pseudomonas flourescens. A few strains of this species are capable of utilizing nitrate to allow anaerobic respiration.

Oil Retention Boom
A floating baffle used to contain and prevent the spread of floating oil on a water surface.

Organic Matter
All of the degradable organics. Living material containing carbon compounds. Used as food by microorganisms.

Organic Nitrogen
The nitrogen combined in organic molecules such as proteins, amines, and amino acids.

Oxidation reduction potential – the degree of completion of a chemical reaction by detecting the ratio of ions in the reduced form to those in the oxidized form as a variation in electrical potential measured by an ORP electrode assembly.

The Williams-Steiger Occupational Safety and Health Act of 1970 (OSHA) is a law designed to protect the health and safety of industrial workers and treatment plant operators. It regulates the design, construction, operation and maintenance of industrial plants and wastewater treatment plants. The Act does not apply directly to municipalities, EXCEPT in those states that have approved plans and have asserted jurisdiction under Section 18 of the OSHA Act. Wastewater treatment plants have come under stricter regulation in all phases of activity as a result of OSHA standards, which also refers to the federal and state agencies which administer OSHA.

Organic Waste
Waste material which comes mainly from animal or plant sources. Organic waste generally can be consumed by bacteria and other small organisms. Inorganic wastes are chemical substances of mineral origin.

Any form of animal or plant life.

Combining elemental compounds with oxygen to form a new compound. A part of the metabolic reaction.

Oxidizing Bacteria
Any substance such as oxygen (O2) and chlorine (Cl2) that can accept electrons. When oxygen or chlorine is added to wastewater, organic substances are oxidized. These oxidized organic substances are more stable and less likely to give off odors or to contain disease bacteria.

The application of ozone to water, wastewater, or air, generally for the purposes of disinfection or odor control.

One organism living on or in another to obtain nourishment, without providing any benefit to the host organism.

Free suspended solids.

Pathogenic Organisms
Bacteria, viruses or cysts which cause disease (typhoid, cholera, dysentery) in a host (such as a person). There are many types of bacteria (non-pathogenic) which do NOT cause disease. Many beneficial bacteria are found in wastewater treatment processes actively cleaning up organic wastes.

Polycyclic Aromatic Hydrocarbons. (rarely, but sometimes used as the abbreviation for polyaluminium hydroxide).

Polychlorinated biphenyls. Aka polychloro-biphenyls. Difficult to remediate chemical used in old-style transformers. Concentrated PCBs used to be referred to as “1268”.

The movement or flow of water through soil or rocks.

Peristaltic Pump
A type of positive displacement pump

pH is an expression of the intensity of the basic or acidic condition of a liquid. Mathematically, pH is the logarithm (base 10) of the reciprocal of the hydrogen ion concentration. The pH may range from 0 to 14, where 0 is most acidic, 14 most basic, and 7 is neutral. Natural waters usually have a pH between 6.5 and 8.5.

An organic compound that is an alcohol derivative of benzene.

A microorganism which gains energy from sunlight (radiant energy).

Product Information Bulletin. General information on a product.

Pin Floc
Excessive solids carryover. May occur from time to time as small suspended sludge particles in the supernatant. There are two kinds: grey – ash like, inert, has low
BOD – indicates old sludge; and brown, but a portion neither settles nor rises, has high BOD – indicates young sludge

One species benefits at the expense of another.

Parts Per Million – the unit commonly used to designate the concentration of a substance in a wastewater in terms of weight i.e. one pound per million pounds, etc. ppm is synonymous with the more commonly used term mg/L (milligrams per liter).

The impairment (reduction) of water quality by agriculture, domestic or industrial wastes (including thermal and radioactive wastes) to such a degree as to hinder any beneficial use of the water or render it offensive to the senses of sight, taste, or smell or when sufficient amounts of waste creates or poses a potential threat to human health or the environment.

Fish farming in which 2 or more compatible or symbiotic species of fish are grown together. Also known as Multiculture.

A chemical formed by the union of many monomers (a molecule of low molecular weight). Polymers are used with other chemical coagulants to aid in binding small suspended particles to form larger chemical flocs for easier removal from water. All polyelectrolytes are polymers, but not all polymers are polyelectrolytes.

Potable Water
Water that does not contain objectionable pollution, contamination, minerals, or infective agents and is considered satisfactory for drinking.

Publicly Owned Treatment Works, as opposed to an industrially owned facility or pipe system.

Preliminary Treatment
The removal of metal, rocks, rags, sand, eggshells, and similar materials which may hinder the operation of a treatment plant. Preliminary treatment is accomplished by using equipment such as racks, bar screens, comminutors, and grit removal systems.

Pretreatment Facility
Industrial wastewater treatment plant consisting of one or more treatment devices designed to remove sufficient pollutants from wastewaters to allow an industry to comply with effluent limits established by the US EPA General and Categorical Pretreatment Regulations or locally derived prohibited discharge requirements and local effluent limits. Compliance with effluent limits allows for a legal discharge to a POTW.

Primary Treatment
A wastewater treatment process that takes place in a rectangular or circular tank and allows those substances in wastewater that readily settle or float to be separated from the water being treated.

A commercial product containing selected strains of natural commensal species of bacteria, known to thrive in the acid pH of the digestive system, while producing valuable food-digesting enzymes, without causing any harm to the host organism. Such products often contain “Probiotic” nutrients, compounds which selectively encourage growth of the included beneficial bacteria, enhancing their ability to “out-compete” undesirable organisms, including pathogenic (disease-causing) species.

Microorganisms which do NOT have an organized nucleus surrounded by a nuclear membrane. Bacteria and Archaea stand alone in this primitive kingdom. Plants, fungi, animals, birds, fish and all other organisms fit into the kingdom of “Eucaryotes”.

A group of motile microscopic animals (usually single-celled and aerobic) that sometimes cluster into colonies and often consume bacteria as an energy source.

Psychrophilic Bacteria
Bacteria whose optimum temperature range is between 0 and 20oC (32 to 68oC), such as those found in Clear-Flo® 7018.

Biological decomposition of organic matter with the production of ill-smelling products associated with anaerobic conditions.

Evenly spaced parallel metal bars or rods located in the influent channel to remove rags, rocks, and cans from wastewater.

Return activated sludge – settled activated sludge that is collected in the secondary clarifier and returned to the aeration basin to mix with incoming raw settled wastewater.

Return Activated Sludge Volatile Suspended Solids.

Rotating biological contactor – an attached culture wastewater treatment system

A pure chemical substance that is used to make new products or is used in chemical tests to measure, detect, or examine other substances.

The use of water or wastewater within (internally) a facility before it is discharged to a treatment system.

Biological reductions/oxidations. These reactions usually require enzymes to mediate the electron transfer. The sediment in the bottom of a lake, sludge in a sewerage works or septic tank will have a very low redox potential and will likely be devoid of any oxygen. This sludge or waste water will have a very high concentration of reductive anaerobic bacteria, indeed the bulk of the organic matter may in fact be bacteria. As the concentration of oxygen increases the oxidation potential of the water will increase. A low redox potential or small amount of oxygen is toxic to anaerobic bacteria, therefore as the concentration of oxygen and redox potential increases the bacterial population changes from reductive anaerobic bacteria to oxidative aerobic bacteria. Measurement of REDOX potential is also referred to as ORP.

Reducing agent Any substance, such as the base metal (iron) or the sulfide ion that will readily donate (give up) electrons. The opposite of an oxidizing agent.

Refractory Materials
Material difficult to remove entirely from wastewater such as nutrients, color, taste, and odor-producing substances and some toxic materials.

The energy producing process of breathing, by which an organism supplies its cells with oxygen and relieves itself of carbon dioxide. A type of heterotrophic metabolism that uses oxygen in which 38 moles of ATP are derived from the oxidation of 1 mole of glucose, yielding 380,000 cal. (An additional 308,000 cal is lost as heat.)

Retention Basin
Rhizosphere Soil surrounding plant roots.

R/O Unit
Reverse Osmosis Unit for water purification in small aquariums and miniature yard-ponds, utilizes a membrane under pressure to filter dissolved solids and pollutants from the water. Two different filter membranes can be used: the CTA (cellulose triacetate) membrane is less expensive, but only works with chlorinated water and removes 50-70% of nitrates, and the TFC membrane, which is more expensive, removes 95% of nitrates, but is ruined by chlorine. R/O wastes water and a system that cleans 100 gallons a day will cost from $400 to $600 with membrane replacement adding to the cost. A unit that handles 140 gallons a day will cost above $700.00.

Respiration rate – the weight of oxygen utilized by the total weight of MLSS in a given time.

Water running down slopes rather than sinking in (again, result of poor humus content) Ex. erosion due to deforestation.

Bacteria that breakdown bodies of dead plants and animals (non-living organic material), returning organic materials to the food chain. Saprophytic bacteria are usually non-pathogenic, too. Most of our products are saprophytic.

Sodium Adsorption Ratio – this ratio expresses the relative activity of sodium ions in the exchange reactions with the soil.

Cubic feet of air per minute at standard conditions of temperature, pressure and humidity (0, 14.7 psi and 50% relative humidity).

Secondary Treatment
A wastewater treatment process used to convert dissolved or suspended materials into a form more readily separated from the water being treated. Usually the process follows primary treatment by sedimentation. The process commonly is a type of biological treatment process followed by secondary clarifiers that allow the solids to settle out from the water being treated.

The process of subsidence and deposition of suspended matter from a wastewater by gravity.

Introduction of microorganisms (such as CLEAR-FLO® 1000 series for aquaculture, 4000 series for grease, and 7000 series for industrial and municipal wastewater) into a biological oxidation unit to minimize the time required to build a biological sludge. Also referred to as inoculation with cultured organisms.

Seine Net
A net designed to collect aquatic organisms inhabiting natural waters from the shoreline to 3′ depths is called a seine net. Most often a plankton seine.

A condition produced by anaerobic bacteria. If severe, the wastewater turns black, gives off foul odors, contains little or no dissolved oxygen and creates a high oxygen demand.

Septicity is the condition in which organic matter decomposes to form foul-smelling products associated with the absence of free oxygen. If severe, the wastewater turns black, gives off foul-odors, contains little or no dissolved oxygen and creates a heavy oxygen demand.

Septic Tank
Untreated liquid household wastes (sewage) will quickly clog your absorption field if not properly treated. The septic tank is a holding tank in which this treatment can take place. When sewage enters the septic tank, the heavy solids settle to the bottom of the tank; the lighter solids, fats and greases partially decompose and rise to the surface and form a layer of scum. The solids that have settled to the bottom are attacked by bacteria and form sludge.

Settleable Solids
Those solids in suspension which will pass through a 2000 micron sieve and settle in one hour under the influence of gravity.

The used water and water-carried solids from homes that flow in sewers to a wastewater treatment plant. The preferred term is wastewater.

Shock Load
The arrival at a plant of a waste which is toxic to organisms in sufficient quantity or strength to cause operating problems. Possible problems include odors and sloughing off of the growth or slime on a trickling-filter media. Organic or hydraulic overloads also can cause a shock load.

Trickling-filter slimes that have been washed off the filter media. They are generally quite high in BOD and will lower effluent quality unless removed.

The settleable solids separated from liquids during processing; the deposits of foreign materials on the bottoms of streams or other bodies of water.

Sludge Age
A measure of the length of time a particle of suspended solids has been retained in the activated sludge process.

Intermittent releases or discharges of industrial wastes.

Matter or compounds capable of dissolving into a solution.
Soluble BOD Soluble BOD is the BOD of water that has been filtered in the standard suspended solids test.

The sediment oxygen demand (SOD) is the rate of the dissolved oxygen consumption in a water body (river, lake or ocean) due to the decomposition of organic matter deposited on the bottom sediment. In shallow nutrient-rich coastal waters in Hong Kong, where algal blooms frequently occur, very high SOD (due to the decomposition of settled algal detritus) has been measured. This may lead to severe oxygen depletion, resulting in massive fish kills. The SOD is often a significant component of the dissolved oxygen budget; its determination provides an important input to mathematical models used in water quality control and environmental impact assessment studies.

A liquid mixture of dissolved substances, displaying no phase separation.

Specific Gravity
Weight of a particle, substance or chemical solution in relation to an equal volume of water.

Spec. Sheet
Specification Sheet. Detailed information of a product including, tests, color, odor, specific gravity, bacterial strains, other major ingredients, etc.

SS Suspended Solids
Solids in suspension in water which can be filtered out on a lab filter.

To convert to a form that resists change. Organic material is stabilized by bacteria which convert the material to gases and other relatively inert substances. Stabilized organic material generally will not give off obnoxious odors.

Stagnation or inactivity of the life processes within organisms.

The removal or destruction of all living microorganisms, including pathogenic and other bacteria, vegetative forms and spores.

Storm Sewer
A separate pipe, conduit or open channel (sewer) that carries runoff from storms, surface drainage and street wash, but does not include domestic and industrial wastes. Storm sewers are often the recipients of hazardous or toxic substances due to the illegal dumping or hazardous wastes or spills created by accidents involving vehicles and trains transporting these substances.

Standard Temperature (25oC) and Pressure (300 mm Mercury).

STP Test
Laboratory test for nitrifiers. For CF1100, 7110 & 1400 to be within specifications, this test must show a positive color change result (from fuschia to yellow) within 7 days. When testing the 50X concentrate of these three products, a positive color change is expected within 24 hours.
Substrate The base on which an organism lives. The soil is the substrate of most seed plants where rocks, soil, water, or other tissues are substrates for other organisms.

Liquid removed from a tank once the solids have settled. When hydrating Clear-Flo formulas, the supernatant is the bran-free liquid which can then be applied by sprayer, without clogging the sprayer.

Supernatant commonly refers to the liquid between the sludge on the bottom and the scum on the surface of an anaerobic digester. This liquid is usually returned to the influent wet well or to the primary clarifier.

Surface-active agent. The active agent in detergents that possesses a high cleaning ability. Used in a spray solution to improve its sticking and wetting properties when applied to plants, algae, or petroleum.

When two or more organisms coexist in a relationship that is strongly co-operative, so that their combined effect exceeds a simple sum of their individual effects.

Breaking down organic compounds and converting the degradation products into new cell growth. An energy using process.

Sludge volume – a settling test using a two liter settleometer to measure sludge quality expressed in percent and related to time, i.e. 80% in five minutes or 30% in 30 minutes. Also used to determine the rate of settling.

Sludge volume index – a settling test used to measure sludge quality.

The volume of sludge blanket divided by the daily volume of sludge pumped from the thickener.

The value obtained in a 30 minute settleometer test.
Taxonomy The classification, nomenclature, and laboratory identification of organisms (Do not confuse with taxidermy – stuffing dead animals)

Total Dissolved Solids is commonly estimated from the electrical conductivity of the water. Pure water is a poor conductor of electricity. Impurities dissolved in the water cause an increase in the ability of the water to conduct electricity. Conductivity is usually expressed in units of microsimens, formerly micromhos or in mg/l, therefore becoming an indirect measure of the level of impurities in the water.

Thermophilic Bacteria
Hot temperature bacteria. A group of bacteria that grow and thrive in temperatures above 113oF (45oC), such as Bacillus licheniformis. The optimum temperature range for these bacteria in anaerobic decomposition is 120oF (49oC) to 135oF (57oC).

Total organic carbon – a measure of the amount of organic carbon in water.

Another method of measuring organic matter in wastewater involves the oxidation of the sample to stable end products in a platinum-catalyzed combustion chamber at 900 degrees C. Total oxygen demand is determined by measuring the oxygen content of the inert carrier gas, nitrogen. TOD measurements are becoming more popular because of their quickness in determining what is entering the plant and how the plant is responding. Analysis time is approximately 5 minutes. The results obtained generally will be equivalent to those obtained in the COD test.

A substance which is poisonous to a living organism.

The relative degree of being poisonous or toxic. A condition which may exist in wastes and will inhibit or destroy the growth or function of certain organisms.

The process by which water vapor is released to the atmosphere by living plants, a process similar to people sweating.

Trickling Filter
An attached culture wastewater treatment system. A large tank generally filled with rock or rings (see Bio-Tower). Wastewater is sprayed over the top of the media, providing the opportunity for the formation of slimes or biomass to remove wastes from the wastewater, through revolving arms which have spray nozzles. Water is pumped from the bottom of a trickle filter to a secondary clarifier.

Total suspended solids.

The amount of suspended matter in wastewater, obtained by measuring its light scattering ability.

Single celled organism, such as bacteria.

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.

An insect or other organism capable of transmitting germs or other agents of disease.

Actual growing state.

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.

Measure of volatile solids, usually expressed as g VS/L/day = grams volatile solids per liter per day.

Waste activated sludge, mg/L. The excess growth of microorganisms which must be removed from the process to keep the biological system in balance.

“sewage” usually refers to household wastes, but this word is being replaced by the term “wastewater”.

A wall or plate placed in an open channel and used to measure the flow of water.

Zoogleal Film
A complex population of organisms that form a “slime growth” on a trickling-filter media 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.