Various implementations include a fluid treatment device. The device includes an outer tube, an inner tube, a plurality of blades, and a media. The outer tube includes an inner surface. The inner tube is coaxially disposed within the outer tube. An outer surface of the inner tube and the inner surface of the outer tube define an annulus that axially extends between the ends of the inner tube. The plurality of blades is disposed within the annulus. The plurality of blades is configured to alter a component of a flow direction of fluid flowing over the blades in a circumferential direction and/or a radial direction. The media is disposed within the inner tube. The inner tube defines a plurality of perforations extending between its outer surface and inner surface. The annulus defines an entire flow path of fluid flowing between the outer tube and the inner tube.