Venturi scrubbers are wet scrubbers that use a change in gas velocity to shear liquid streams (usually water) into tiny target droplets into which particulate and soluble gases are transferred. They are considered as a workhorse of the available air pollution control technologies given their low capital cost, reliability, and effectiveness on a variety of applications. They tend to use more energy than alternative designs, particularly on applications treating over 50,000 actual cubic feet per minute (acfm) of gases. Venturi scrubbers are used where the collected product can be handled wet. They are often used on processes, such as calciners and dryers, wherein the blowdown from the scrubber can be returned to a wet portion of the process. They can also handle the heavy-dust loadings, which can occur from these sources. Venturi scrubbers can ingest dust loadings of over 30 grs/dscf (grains per dry standard cubic foot) if designed correctly. Figure 19.1 shows a rectangular throat Venturi scrubber, a workhorse of the wet scrubbing industry.