What does the term 'entrain' refer to in water distribution?

The term 'entrain' in the context of water distribution refers to the process of trapping or carrying along gas bubbles or particulate matter within a fluid flow. This is particularly relevant in various water treatment and distribution processes, where air or gas bubbles may be introduced into the water stream. When bubbles are entrained, they can affect the physical behavior of the water, potentially impacting processes such as mixing and transportation in the distribution system. Understanding this concept is crucial for effectively managing water quality and flow characteristics in a distribution network.

Other options like filtering out contaminants, disinfecting water, or stabilizing pH levels involve different processes and mechanisms that do not align with the specific definition of entrainment.