Glossary of Water and Wastewater Terms

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5 random terms from our glossary

logarithmic scale (LOG-uh-RITH-mick)

A scale on which each equal increment increases by a factor of 10 (e.g., 100, 101, 102) instead of by 1 (e.g., 1, 2, 3, 4), and the corresponding numbers are 100 = 1, 101 = 10, 102 = 100, etc. For numbers less than 1, the corresponding numbers are 10-1 = 0.1, 10-2 = 0.01, 10-3 = 0.001, etc. On a logarithmic scale, there are no zero or negative values. Instead, the scale starts with the smallest positive factor of 10 desired to display the data. This type of scale is typically used to display skewed data and show relative differences.

rabbling

The process of moving or plowing the material inside a furnace by using the center shaft and rabble arms.

retention

(1) That part of the precipitation falling on a drainage area that does not escape as surface stream flow during a given period. It is the difference between total precipitation and total runoff during the period, and represents evaporation, transpiration, subsurface leakage, infiltration, and, when short periods are considered, temporary surface or underground storage on the area. (2) The delay or holding of the flow of water and water-carried wastes in a pipe system. This can be caused by a restriction in the pipe, a stoppage, or a dip. Retention also means the time water is held or stored in a basin or wet well. Also called detention.

GHS

See Globally Harmonized System of Classification and Labeling of Chemicals.

volatile solids

Those solids in water, wastewater, or other liquids that are lost on ignition of the dry solids at 1,022°F (550°C). Also called organic solids and volatile matter.