Abstract: A method for treating at least one liquid fluid comprising a high water content, and including a volatile fraction and a heavy fraction, in order to separate said two fractions. Said method consists in burning at least one gas fluid, recuperating the heat released by said combustion for subsequently heating the liquid fluid. The heated liquid fluid is pressurised and then expanded so as to separate the volatile fraction from the heavy fraction. The volatile fraction is then burnt with the gas fluid. The heavy fraction is extracted from the process to be subsequently treated. The invention also concerns an installation for implementing the treatment method.

Abstract: In a biological water purification process polluted water, including surface water to be made potable, sewage water or industrial water, is percolated through a submerged fixed bed of granular material such as activated carbon, chamottes, raw clays, etc., with an oxygenated gas being upwardly injected at an intermediate level of the bed. The water and gas delivery rates are controlled to satisfy the following relations: ##EQU1## wherein Q.sub.1 is the delivery of oxygenated gas in m.sup.3 /hr,Q.sub.2 is the delivery of water to be treated in m.sup.3 /hr,.epsilon. is the porosity of the granular material bed,.alpha. is the maximum fraction of the volume that can be occupied by the gas without affecting the effectiveness of the treatment,S is the bed section in m.sup.2,h is the height of the bed in meters,v is the vertical component of the average speed of the ascending gas bubbles in m/hr,K.sub.1 is a constant corresponding to the fraction of volume of bed occupied by immobilized gas pockets in m.sup.3,K.sub.