Abstract: An apparatus for removing liquid from a solid suspension includes a screw conveyor in a housing having a suspension inlet, a liquid outlet and a separate outlet for the thickened solids. To increase the thickening effect, the faces of the screw threads are coated or treated to cause the coefficient of friction of the front, thrust faces to be higher than that of the rear faces. The coefficients can also be varied longitudinally, either continuously or in stages.

Abstract: A process for treating a liquid effluent, such as waste water, containing biodegradable organic materials in solution and/or in suspension which consists in causing this effluent to flow over an adsorbing material previously seeded with microbian flora and on which said organic materials spread out depending on their ease of adsorption while thus defining successive layers.This process is characterized in that the adsorbing material is in the form of as many independent beds as there are layers, these beds being disposed in series.

Abstract: A flotation apparatus comprising a treatment chamber provided, at one of its ends, with an inlet for the liquid to be treated circulating without turbulence and, at the other end, an outlet for the treated liquid, an inlet pipe for the treatment water under high compression charged with gas being disposed at the lower part of said treatment chamber.In this apparatus the inlet pipe for the water under high compression is located below and in the neighborhood of the inlet for the liquid to be treated in the treatment chamber, an outlet pipe for the treatment water being disposed at the lower part of the chamber, below and in the neighborhood of the outlet for the treated liquid, means for allowing the passage of the micro-bubbles coming from the water under high compression being furthermore provided to create between the two ends of the chamber two distinct, superimposed and parallel flows, the upper one for the liquid to be treated, the lower one for the water under high compression.