Glossary

Aeration Basin
A basin or tank used to degrade organic matter. Diffused air is used to accomplish this treatment process.

Bar Screens
A screen or screens consisting of parallel bars, either vertical or inclined, that is placed in a flow to remove debris. The screenings are raked from the screen by manual or mechanical means.

Biological Filtration
The process of passing a liquid through the medium of a biological filter, thus permitting contact with attached living organism films that adsorb and absorb fine suspended, colloidal, and dissolved solids and release end products of biochemical action.

Biological Oxidation
The process whereby living organisms in the presence of oxygen convert the organic matter contained in wastewater into a more stable or a mineral form.

BOD
Abbreviation for biochemical oxygen demand The quantity of oxygen used in the biochemical oxidation of organic matter in a specified time, at a specified temperature, and under specified conditions.

Disinfection
The process of adding chemicals or other means to destroy viral or bacterial content in the treated wastewater prior to discharge to the receiving stream.

Effluent
Completely treated wastewater flowing out of the treatment plant.

Effluent Filters
The process that causes treated wastewater to pass through a bed of media (sand and/or anthracite) to physically remove particulate matter from the flow.

Flocculation
In water and wastewater treatment, the agglomeration of colloidal and finely divided suspended matter after coagulation by gentle stirring by either mechanical or hydraulic means. In biological wastewater treatment where coagulation is not used, agglomeration may be accomplished biologically.

Grit
The heavy suspended mineral matter present in water or wastewater, such as sand, gravel, cinders.

Grit Removal Equipment
Equipment to remove heavy suspended matter from the treatment plant flow.

Influent Water
Liquid flowing into a reservoir, basin, treatment plant, or treatment process.

Headworks
Initial treatment process which can include bar screens, flow metering and grit removal equipment.

Pipe
A closed conduit that diverts or conducts water from one location to another.

Primary Clarifier
A device designed to permit solids to settle and be separated from the flow. Also known as a settling tank or sedimentation basin.

Sanitary Sewer
A sewer that carries liquid and waterborne wastes from residences, commercial buildings, industrial plants, and institutions together with minor quantities of ground, storm, and surface water that are not admitted intentionally.

Secondary Clarifier
The settling basin which follows the aeration basins and allows for separation of solids from the flow stream. This equipment also allows for the return of solids to the aeration basins.