Glossary of Water and Wastewater Terms

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5 random terms from our glossary


The water leaving a centrifuge after most of the solids have been removed.


A community's used water and water-carried solids (including used water from industrial processes) that flow to a treatment plant. Stormwater, surface water, and groundwater infiltration also may be included in the wastewater that enters a wastewater treatment plant. The term sewage usually refers to household wastes, but this word is being replaced by the term wastewater.

Storativity (S)

The volume of groundwater an aquifer releases from or takes into storage per unit surface area of the aquifer per unit change in head. Also called the storage coefficient.


A point where a pipe or system structure has been damaged or has a fault. Also called a fault. Also see SURFACED DEFECT.

Septic Tank

A system sometimes used where wastewater collection systems and treatment plants are not available. The system is a settling tank in which settled sludge and floatable scum are in intimate contact with the wastewater flowing through the tank and the organic solids are decomposed by anaerobic bacterial action. Used to treat wastewater and produce an effluent that is usually discharged by subsurface leaching. Also referred to as an interceptor; however, the preferred term is septic tank.