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. Nitrification: 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
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
Non-woven: A porous web or sheet produced by mechanically, chemically or thermally bonding together polymers, fibers or filaments. Nucleic acid: An organic acid consisting of joined nuceleotide complexes; the principal tyes are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nutrients: 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 presense of oxygen, such as Pseudomonas flourescens. A few strains of this species are capable of utilizing
Oil Retention Boom: A floating baffle used to contain and prevent the spread of
Open area: The proportion of total screen area that is open space. Expressed as a
Organic matter: All of the degradable organics. Living material containing carbon
Organic nitrogen: The nitrogen combined in organic molecules such as proteins,
ORP: 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. OSHA: 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
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.
Oxidation: Combining elemental compounds with oxygen to form a new
Oxidizing bacteria: Any substance such as oxygen (02) and chlorine (Clj), 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.
Ozonation: The application of ozone to water, wastewater, or air, generally for the
Parisitism: One organism living on or in another to obtain nourishment, without
Particle: A relatively small subdivision of matter ranging in diameter from a few angstroms (as with gas molecules) to a few millimeters (as with large raindrops). The particle can have various shapes and dimensions.
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.
PAH: Polycyclic Aromatic Hydrocarbons, (rarely used as abbreviation for
PCB: Polychlorinated biphenyls. Aka polychloro-biphenyls. Difficult to remediate chemical used in old-style transformers. Concentrated PCBs used to be referred to
Percolation: The movement or flow of water through soil or rocks.
Peristaltic pump: A type of positive displacement pump.
Permeability: Ability of a membrane or other material to permit a substance to pH: 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.
Phenol: An organic compound that is an alcohol derivative of benzene.
Phototroph: A microorganism which gains energy from sunlight (radiant
PIB: Product Information Bulletin. General information on a product.
Pin Floe: Excessive solids carryover. May occur from time to time as small suspended sludge particles in the supernatant. There are two kinds: grey -ashlike, inert, has low BOD - indicates old sludge; and brown, but a portion neither settles nor rises, has high BOD - indicates young sludge.
Plain weave: Another name for square weaves. See weave patterns.
Plane wave: An electromagnetic wave with electric and magnetic components ppm: Parts Per Million - the unit commonly used to designate the concentration of a substance in a wastewater in terms of weight ie. one pound per million pounds, etc. ppm is synonymous with the more commonly used term mg/L (milligrams per
Pollution: 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.
Polyculture: Fish farming in which 2 or more compatible or symbiotic species of fish are grown together. Also known as Multiculture.
Polymer: 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 floes for easier removal from water. All polyelectrolytes are polymers, but not all polymers are
Pore size: The distance between two adjacent warp or weft threads, measured in the projected plane. Only applies to fabrics above 10 microns.
Potable water: Water that does not contain objectionable pollution, contamination, minerals, or infective agents and is considered satisfactory for drinking. POWT: Publicly Owned Treatment Works, as opposed to an industrially owned
Predation: One species benefits at the expense of another. 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,
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.
PRD: Plain Reverse Dutch weave. See weave patterns.
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.
Procaryotic organism: Microorganisms which do NOT have an organized nucleus surrounded by a nuclear membrane. Bacteria and blue-green algae fit in this category.
Protozoa: 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 20° C (32 to 68° F).
Putrefaction: Biological decomposition of organic matter with the production of ill-smelling products associated with anaerobic conditions.
Pyrogenic: A fever-producing substance. The presence of these substances is determined by the Limulus Amebocyte Lysate (LAL) test and measured in EU/ml (endotoxin units per milliliter).
Was this article helpful?