Treating an organic effluent is disclosed. The effluent is fed in a continuous flow at a rate q via a first chamber maintained at a first pressure and/or directly through a first narrowing to a second chamber or container maintained at a second medium pressure by the injection of air into the second chamber at a rate Q in order to obtain an emulsion in the second chamber. A head loss is generated in the emulsion optionally modified by a second and/or third narrowing or a feed valve for a third chamber maintained at a third pressure in the region immediately downstream of the second or third narrowing and/or valve. A flocculant is injected into the region of the third chamber. The emulsion at atmospheric pressure then being degasified and the emulsion thus degasified being recovered in a filtration or decanting device.