That portion of sludge from the secondary clarifier in the activated sludge process that is wasted to avoid a buildup of solids in the system.

Sludge withdrawn from the secondary clarifier in the activated sludge process, consisting of micro-organisms, non-living organic matter, and inorganic materials.

A common method of disposing of pollutants in wastewaters. In the process, large quantities of air are bubbled through wastewaters that contain dissolved organic substances in open aeration tanks. Bac [..]

The process of method of bringing about intimate contact between air and a liquid.

A chamber for injecting air into water.

Bacteria that require free (elementary) oxygen for growth.

Bacteria that grow in the absence of free oxygen and derive oxygen from breaking down complex substances.

The process by which bacteria and other types of microorganisms consume dissolved oxygen and organic substances in waste water, using the energy released to convert organic carbon into carbon dioxide [..]

A quantitative measure of the oxygen needed by bacteria and microorganisms for the biological oxidation of organic wastes in a unit volume of waste water. BOD is generally measured in milligrams per l [..]

A quantitative measure of the amount of oxygen required to oxidize all organic compounds in a unit volume on waste water - non-biodegradable as well as the BOD. The COD level can be determined more re [..]