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 Z5 random terms from our glossary
pressure control
A switch that operates on changes in pressure. Usually this is a diaphragm pressing against a spring. When the force on the diaphragm overcomes the spring pressure, the switch is activated
variable frequency drive (VFD)
An electronic device that is used to vary the frequency of an electric current applied to motor. While the motor is not running, it is first connected to a low-frequency source; then, the frequency is incresaed gradually until the motor and pump (or other driven machine) are operating at the desired speed. This allows operators to precisely control the rotational speed of the motor.
aerobic digestion (air-o-bick)
The breakdown of wastes by microorganisms in the presence of dissolved oxygen (DO). This digestion process may be used to treat only waste activated sludge, or trickling filter sludge and primary (raw) sludge, or waste sludge from activated sludge treatment plants designed without primary settling. The sludge to be treated is placed in a large aerated tank where aerobic microorganisms decompose the organic matter in the sludge. This is an extension of the activated sludge process.
laminar
Smooth or viscous flow; not turbulent flow.
sliplining
A pipe rehabilitation technique accomplished by inserting flexible polyethylene pipe into an existing, deteriorated pipe.
