Process selection based on contaminant properties
Other considerations in process selection
Removal efficiency
Reliability
Indicates a process’s ability to continuously meet the treatment objective.
Some processes are very reliable and are able to meet treatment objectives despite changes in raw-water quality or operating parameters. 
A process must have mechanical and hydraulic reliability.
Consumer expect to have water available continuously.
Process that require very little maintenance, have few moving parts, or operate by gravity tend to be more reliable than process with many complex components