Glossary of Water and Wastewater Terms

A B C D E F G H I J K L M N O P Q R S T U V W Y Z

5 random terms from our glossary

Permissible Exposure Limit (PEL)

The legal limit in the United States for exposure of a worker to a hazardous substance (such as chemicals, dusts, fumes, mists, gases, or vapors) or agents (such as occupational noise). OSHA sets enforceable permissible exposure limits (PELs) to protect workers against the health effects of excessive exposure. OSHA PELs are based on an 8-hour time-weighted average (TWA) exposure. Permissible exposure limits are listed in the Code of Federal Regulations (CFR) Title 29 Part 1910, Subparts G and Z. Also see TIME-WEIGHTED AVERAGE (TWA). Also see TIME-WEIGHTED AVERAGE (TWA).

Alliance Of Certified Operators, Lab Analysts, Inspectors, And Specialists (ACEOPS)

A professional organization for operators, lab analysts, inspectors, and specialists dedicated to improving professionalism; expanding training, certification, and job opportunities; increasing information exchange; and advocating the importance of certified operators, lab analysts, inspectors, and specialists. For information on membership, visit AceOps at aceops.org or phone (515) 266-0248.

Float on the System

A method of operating a water storage facility. Daily flow into the facility is approximately equal to the average daily demand for water. When consumer demands for water are low, the storage facility will be filling. During periods of high demand, the facility will be emptying.

CSO

Combined Sewer Overflow. Wastewater that flows out of a combined sewer (or lift station) as a result of flows exceeding the hydraulic capacity of the sewer or stoppages in the sewer. CSOs exceeding the hydraulic capacity usually occur during periods of heavy precipitation or high levels of runoff from snow melt or other runoff sources.

Total Dynamic Head (TDH)

When a pump is lifting or pumping water, the vertical distance (in feet or meters) from the elevation of the energy grade line on the suction side of the pump to the elevation of the energy grade line on the discharge side of the pump. The total dynamic head is the static head plus pipe friction losses.