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Definitions & Abbreviations

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AL (Action Level): The concentration of a contaminant, which, if exceeded, triggers a treatment or other requirement, which a water system must follow.

Backwash, Backwash Water: A backward flow of water through a filter bed, allowing trapped debris and floc to be cleared from the filter media.

Backwash Station: An area, just downstream from the equalization station, where backwash water, from the filter cleaning process, is pumped to the Thickener Tanks.

Chlorine: A highly reactive gas, used as a disinfectant in water treatment.

Clearwell: A finished water storage area. Filtered water enters the Clearwell from the filter beds. Clearwell water is pumped to the distribution system, once it is treated with orthophosphate.

Coagulant: A material, such as PACl (polyaluminum chloride), which will form a precipitate in water, and cause the agglomeration of finely divided particles into larger particles, which can then be removed by settling and/or filtration.

Coliform, Coliform bacteria: A group of bacteria that are normally abundant in the intestinal tracts of human and other warm-blooded animals and are used as indicators (being measured as the number of individuals found per 100 milliliter of water) when testing the sanitary quality of water.

Contaminant: Any physical, chemical, biological, or radiological substance or matter in water that may be harmful to human health or which degrades the palatability of water.

Decant: The draw off from the upper layer of liquid after the heaviest material has settled

Disinfection, Disinfectant: is a treatment, which destroys or renders inactive, harmful microorganisms (bacteria, viruses and cysts) to levels deemed to be safe by public health standards; viable microorganisms may still be present.

Disinfection By-Products (DBP): Byproducts of the disinfection of water by chlorine and chlorine compounds. DBP are regulated by the EPA because they are considered harmful in concentrated amounts. Trihalomethanes (THM’s) and Halogenated Acetic Acids (HAA’s) are among the most regulated DBP’s.

Distribution System: The system of pipes and valves supplying water to communities and industries.

Equalization Basin: An area upstream from the filter beds that collects backwash water from the filter cleaning process. The backwash contents from the equalization basin are directed into the backwash station. .

Filter Beds: 40 rapid, anthracite sand, filters designed to remove undissolved or suspended particles from water by recirculating the water through anthracite media. Filtered water is directed into the Clearwell to await distribution demand.

Filter Aid: A nonionic polymer or a positively charged coagulant such as polyaluminum chloride used to “tighten” filters, and improve filtration. A filter aid is only used, when necessary.

Floc: The clumps or tufts formed when suspended particles combine with chemical substance or compound that promotes the combination, agglomeration, aggregation or coagulation of suspended particles in the water.

Flocculation Chambers: Chambers with large, slow moving paddles. The slow mixing action promotes floc formation.

Fluoride: Sodium silicofluoride, a fluoride compound added to drinking water, to promote dental health.

HAA (Halogenated Acetic Acids): Organic compounds, which are disinfection by-products of the chlorination of drinking water, currently the EPA lists HAA’s as a health advisory

Intake: A structure located in the Emerald Channel at the Northeastern portion of Lake Erie, just downstream from the Niagara River, which provides source water for Buffalo Water Authority’s water treatment process.

Low Lift Pumps: Centrifugal pumps that direct water from the raw water conduit to the underground flocculation and settling basins.

MCL (Maximum contaminant level): The highest level of contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology

MCLG (Maximum contaminant level goal): The level of contaminant in drinking water below which there is no known or expected risks to health, MGLGs allow for a margin of safety.

MRDL (Maximum Residual Disinfectant Level): The highest level of a disinfectant (chlorine) allowed in drinking water (4.0 ppm). There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.

n/a (NA): Not any. NLS: No limit set. ND: Not Detected.

NTU (Nephelometric Turbidity Units): A measure of clarity (turbidity) of water; turbidity in excess of 5NTU is just noticeable to the average person.

Nonionic polymer: A long-chained, non-charged compound used to concentrate floc into sludge, and also used as a filter-aid, in the water treatment process

Ortho- phosphate: A chemical blend used as a TT (Treatment Technique) used to reduce the level of lead and copper contamination in drinking water.

Pathogenic: Disease causing

ppb: Parts per billion, or micrograms per liter (mg/L).

ppm: Parts per million, or milligrams per liter (mg/L).

Polyaluminum Chloride: A coagulant used in water treatment, used to form floc and also used as a filter-aid, in the water treatment process

Potable water: water of a quality suitable for drinking, that meets drinking water standards.

Rapid Mix (Chemical Induction Unit): A structure designed to mix chemicals in the treated water conduit.

Raw Water: Lake Erie water, used by the Buffalo Water Authority as its source water.

Raw Water Conduit: Large metal pipe bringing untreated lake water from the intake to the onshore screen house, then to the chemical treatment points at the water treatment plant.

Screen House: An onshore treatment building containing a series of large, traveling screens. These screens are designed to remove large objects and debris from lake water prior to chemical water treatment.

Sedimentation, Settling: The process of suspended solid particles settling out (going to the bottom of the vessel) in water.

Settling Basins: Large, underground basins allowing heavy floc to settle out of treated water, prior to filtration. The Buffalo Water Authority has 2 settling basins, north & south.

Sludge: Concentrated backwash floc. Sludge is directed to an onsite lagoon.

Source Water: See Raw Water.

Thickening Tanks: An onsite backwash treatment facility designed to concentrate and separate filter backwash into its’ sludge and decant components. The Thickening Tanks use a nonionic polymer and settling tubes to treat filter backwash.

TOC (Total Organic Carbon); SUVA (Specific Ultraviolet Absorption); DOC (Dissolved Organic Carbon); UV254: A measure of the organic content of the water. This is a precursor to disinfection by-product when combined with the chlorination of drinking water

Treated Water Conduit: Large metal pipe directing chemically treated water to various stages of the water treatment process.

TT (Treatment Technique): A required process intended to reduce the level of contamination in drinking water.

TTHM (Total Trihalomethane): Organic compounds, which are disinfection by-products of the chlorination of drinking water. Some people who drink water with TTHMs in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous system, and may have an increased risk of getting cancer.

Turbidity is a measure of the cloudiness of the water. We monitor it because it is a good indicator of the effectiveness of our filtration system. State regulations require that turbidity must always be below 5 NTU. The regulations require that 95% of the turbidity samples collected have measurements below 0.5 NTU.

Washwater Tanks: Tanks, holding potable water, used to backwash filter beds.

Weir: is a structure that extends across the width of a channel and is used to impound, measure, or in some way alter the flow of water through the channel.

90th % Value: The value reported for lead & copper represents the 90th %. A % is a value on a scale of 100 that indicates the % of a distribution that is equal to or below it. The 90th % is equal to or greater than 90% of the lead & copper values detected at your water system.