Scrubbers remove odors, pollutants, acid gases and chemical wastes from air and liquid streams or from biogas. In a wet scrubber, the polluted stream flows counter current past water or a liquid chemical, which removes the undesirable component of the gas or liquid. Chemical scrubbing typically requires large amounts of caustic chemicals.
Accurate level monitoring of water in the scrubber vessel requires a control to feed the correct amount of make-up water to the recycle reservoir. Located in the wet scrubber shell, the level-monitoring device for water-out control should be equipped with a level alarm.