a throat section of a venturi for passing a flow of fluid therethrough comprises a plurality of spaced parallel physical barriers . the physical barriers are oriented parallel to the direction of fluid flow through the throat section . the throat section is installed in a throat zone of a venturi scrubber defined by an upstream zone having an unobstructed upstream section , a throat zone having the throat section , and a downstream section . the spaces between adjacent barriers are from about 3 / 16 inches to about 8 inches so as to create free stream zones between adjacent barriers . each barrier may have a selected length which decreases with distance from the axis of the throat section . a method for treating a stream of effluent fluid containing entrained particulates by introducing the effluent fluid and target droplets into the throat section so as to promote impaction therebetween is also described .