Velocity: The rate of change in position, or the change in speed over a period of time in a specific direction, usually given as metres per second, for a direction.
Vertical flow settling clarifiers:
A type of sedimentation device where the water for processing flows through it vertically.
Virus: Molecules of nucleic acid (RNA or DNA) that can enter cells and replicate in them.
Volatile (VOL-uh-tile): A substance that is capable of being evaporated or easily changed to a vapour at relatively low temperatures. For example, petrol is a highly volatile liquid.
Volumetric: A measurement based on the volume of some factor. Volumetric titration is a means of measuring unknown concentrations of water quality indicators in a sample by determining the volume of a titrant or liquid reagent needed to complete particular reactions.