Degremont

Suez International

Laure Graveleau

Troy Holst

Marie Secondat

A method for biologically treating effluent involves pouring the effluent into a basin in which mobile supports are submerged for developing a biofilm and for carrying out a treatment by fixed fluidized bed, aerating the effluent in the basin with a distribution of air flow, from the bottom of the basin, according to a floor configuration, the aeration supplying air for treating the nutrients, and keeping the supports moving, regulating the aeration to modulate the air flow depending on at least one parameter taken from the following parameters: the residual oxygen concentration, and/or the concentration of oxygen and the concentration of N&#x2014;NH4, and/or the permitted load; modifying the distribution of the air supply from the floor configuration to a spiral flow configuration when the operating conditions result in an air flow lower than a minimum air flow required to keep the mobile supports moving in the floor configuration.

Method and facility for the aerobic biological treatment of effluent, in particular wastewater

Process for treating effluents containing nitrogen in ammonium form, using a sequential biological reactor (), according to which: a volume of effluents to be treated in one complete cycle is introduced into the biological reactor in one or more successive fractions by volume, each fraction by volume being treated during a subcycle; each subcycle comprises a phase of feeding with a fraction by volume, and at least a first aerated step, during which total or partial oxidation of the ammonium to nitrites takes place by injection of air or of oxygen into the effluent, a settling out and emptying step taking place after the end of the complete cycle; the weight of N&#x2014;NHto be treated is determined from the volume of effluents in the reactor at the end of the feeding phase, and from the difference between the initial N&#x2014;NHconcentration in the reactor and a concentration desired at the end of the aerated step, a maximum aeration time TM is dedicated to the aerated step, and an initial air flow rate Qairinit, for the beginning of the aerated step, is determined by taking into account the weight of N&#x2014;NHto be treated and the maximum aeration time TM.

Process for treating effluents containing nitrogen in ammonium form, and equipment for implementing this process

The invention relates to a method for biologically treating waste water, using a set of micro-organisms having different metabolic spectra, in order to eliminate carbon and nitrogen, even phosphorus. Some of the micro-organisms are fixed to mobile solid carriers () and form a fluidised fixed biomass. Some of the micro-organisms are free to be used in an activated mud treatment. To this end, a first non-aerated treatment zone () is followed by a second aerated treatment zone (); the treated effluent is subjected to a solid/liquid separation by flotation () at a speed higher than 10 m/H; and part of the mud recovered by flotation is recirculated () towards the activated mud treatment, said recirculation being controlled () so that the MES concentration of the effluent subjected to the liquid/solid separation remains compatible with the retained flotation.

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Fresnes, France

Laure Graveleau