What points one should know regarding wet scrubber design for boiler?

Talking in general regarding the wet scrubber one can say that it is a specially designed device that is basically used for removal of various pollutants from exhausted gases or from furnaces or another device. The devices are based on the use of scrubbing liquid for the removal of the pollutants. But the general information related to the wet scrubber is already known to the people and therefore that is not something needed to be discussed.