Apparatus for removing suspended impurities from a liquid (e.g., wastewater), methods of use, and systems including such apparatus. In an embodiment, an apparatus may include a vessel defining a chamber for receiving gas induced liquid influent through an inlet, the influent including suspended impurities. A riser tube may be provided within the vessel, in fluid communication with the inlet so that liquid influent introduced into the vessel through the inlet is introduced into the riser tube. One or more coalescing members may be disposed within the riser tube. The coalescing members may be sufficiently small to be easily removable by hand, without requiring a crane. The coalescing members may be freely disposed within the riser tube, rotatable within the flow of the liquid influent, aiding the coalescing members in exhibiting some degree of “self-cleaning”, so as to be less prone to fouling and clogging.
