Abstract: A plurality of elongated hollow, circular, foraminous substantially vertical tubes contiguously stacked transversely to the direction flowing liquid such as waste water containing foreign matter, i.e., settable solids and free oil, in a coalescer-separator apparatus provide a filter body providing for significant surface area contact by the liquid on both inside and outside surfaces of the tubes to entrap the foreign matter but defining substantially vertical passages permitting the entrapped foreign matter to be gravity separated with the lighter matter coalescing and floating upwardly and the heavier matter settling downwardly so that substantially clarified effluent flows from the apparatus. The stacked tube filter body is contained within an insulated closed container of a sufficient capacity, and the arrays of holes in the tube walls are coordinated with respect to the intended volumetric capacity of the apparatus, so that turbulence in the liquid flowing through the filter body is minimized.

Abstract: Waste water containing pollutants such as suspended solids and emulsified oil is pumped continuously through a self-contained separating or polishing system utilizing a simplified plug-in module to remove the pollutants. The suspended solids are removed by mechanical filtration and the emulsified oil is separated by coalescing oil into floatable droplets which can be skimmed from a water surface and withdrawn for external accumulation. The treated waste water may be returned for further use or pumped to other facilities for further treatment.