FR2993877A1 - Installation, useful for treating an aqueous effluent charged with nitrogen from e.g. aquarium, comprises a reactor comprising catalyst, and a unit for pumping a part of recirculating flow of fluid from fluid chamber towards chamber - Google Patents

Abstract

The installation for treating an aqueous effluent charged with nitrogen in the presence of a catalyst (3) on a porous support comprising two metals, comprises: a reactor (2) comprising the catalyst provided between a chamber of catalyst feed stream and a fluid chamber (5) for discharging the fluid flow from the catalyst; a unit (6) for pumping a part of the recirculating flow of fluid from the fluid chamber towards the chamber; and a feed device (7) for supplying hydrogen gas and/or formic acid to a recirculating circuit. The installation for treating an aqueous effluent charged with nitrogen in the presence of a catalyst (3) on a porous support comprising two metals, comprises: a reactor (2) comprising the catalyst provided between a chamber of catalyst feed stream and a fluid chamber (5) for discharging the fluid flow from the catalyst; a unit (6) for pumping a part of the recirculating flow of fluid from the fluid chamber towards the chamber; and a feed device (7) for supplying hydrogen gas and/or formic acid to a recirculating circuit. The first metal comprises copper, tin, zinc, indium, nickel, silver, iron, cobalt, or germanium. The feed device is connected with the recirculation circuit placed downstream from a throttle equipping the recirculation circuit to permit recirculation of hydrogen gas by a venturi effect. The feed device is formed by an electrolysis device including two electrodes to produce hydrogen and oxygen, respectively. The electrodes are placed in compartments of the electrolysis device. One of the compartments of the electrode producing oxygen is provided with a vent for an evacuation of oxygen in the atmosphere. The compartment of the electrode producing hydrogen communicates with the recirculation circuit via a tube radial to the recirculation circuit and placed downstream from the throttle of the recirculation circuit. The tube emerges in the compartment of the electrode producing hydrogen or in a space communicating with the compartment. A formic acid feeding attachment includes a formic acid tank, a pump for supplying formic acid to the recirculation circuit from the tank, a pH measuring unit to measure the pH of the recirculation circuit, and a unit for controlling the pump according to data provided by the pH measuring unit. The fluid chamber is provided with a unit for separating gas/liquid such as a baffle, an upstream compartment and a downstream compartment for a circulation by overflow of the upstream compartment towards the downstream compartment. The pumping unit is present in an entry placed in the downstream compartment below an overflow area. The chamber comprises an input for supplying fluid independent of an outlet of the recirculation circuit in the chamber. The pumping unit comprises two outputs. The input of the chamber independent of the outlet of the recirculation circuit and the output of evacuation of flow of fluid outside the reactor are connected to an installation of modification of mineralization of the effluent to be treated such as an electrodialyzer. The electrodialyzer includes two electrodes placed inside an enclosure and a set of anionic and cationic membranes alternatively placed between two series of cells. Each cell of the first series of cells is provided with a fluid input and a fluid output. The fluid inputs are in communication with a fluid distributor. The fluid outputs emerge in a fluid collector. The fluid distributor is connected to the output of evacuation of flow of fluid outside the reactor. The fluid collector is connected to the input of supply flow of fluid. Each cell of the second series of cells is provided with an input and an output of fluid. The electrodialyzer further comprises a probe for measuring a dissolved total salt concentration of the effluent and a unit for inverting a polarity of the electrodes according to data provided by the probe.

Description

The present invention relates to an installation and a method for treating an aqueous effluent charged with nitrogenous chemical species, using a catalyst comprising at least two porous support metals.

It relates more particularly to a water treatment facility, such as an aquarium, fish farm, septic tank, groundwater, watercourse, sewage treatment plant with a view to reducing or eliminating wastewater treatment plants. nitrogenous species that it contains without harm to the environment for fauna and flora. Over the past decades, it has been found that the nitrogen content of water has increased considerably to non-standard concentrations of more than 50 mg / ml. It has therefore become very important to develop water treatment processes to reduce or eliminate their nitrite and nitrate content. Various methods for reducing nitrites and nitrates, in particular chemically, have been described. These processes use a catalyst comprising one or more metals on a porous support. In the presence of hydrogen, the catalyst reduces the nitrogen species into increasingly simple molecules until nitrogen and gaseous oxygen are obtained. This technology effectively converts almost all nitrates into nitrogen and oxygen. This technology consumes little energy and is sustainable over time. However, until now, this technology has remained on a laboratory scale and has been tested only over a short period of time and on low volume samples. An object of the present invention is therefore to provide a treatment plant whose design allows a continuous treatment of an effluent to be treated without impact on fauna and flora possibly present and without harm to the environment.

Another object of the present invention is to provide an effluent treatment plant whose design allows optimization of the operation of the catalyst.

For this purpose, the subject of the invention is an installation for treating an aqueous effluent charged with nitrogenous chemical species, using a catalyst comprising at least two metals M, M 'on a porous support, the first metal M being selected from platinum (Pt), palladium (Pd), ruthenium (Ru), iridium (Ir), rhodium (Rh), the second metal M 'being selected from copper (Cu), tin (Sn), zinc (Zn), indium (In), nickel (Ni), silver (Ag), iron (Fe) or cobalt (Co), germanium (Ge), characterized in that said installation comprises a reactor comprising said catalyst arranged between a feed chamber of the fluid flow catalyst and a fluid flow evacuation chamber derived from said catalyst, pumping means capable of recirculating a part of the flow of fluid from the evacuation chamber towards the supply chamber and a device for supplying gaseous hydrogen and / or formic acid thereto. recirculation.

The presence of a recirculation circuit makes it possible to easily and controllably feed the catalyst into a reducing agent, such as hydrogen or formic acid, also called methanoic acid.

In a first embodiment of the invention, the reducing agent supply device is a device for supplying gaseous hydrogen. Preferably, the hydrogen gas supply device communicates with the recirculation circuit at a zone of the recirculation circuit disposed downstream of a throat equipping said recirculation circuit to allow, by venturi effect, a supply circuit recirculating hydrogen gas.

This solution makes it possible to dispense with additional pumping means for supplying the reactor with reducing agent.

Preferably, the device for supplying gaseous hydrogen is formed by an electrolysis device comprising two electrodes each capable of producing one hydrogen (dihydrogen), the other oxygen (oxygen).

This electrolysis device can, in an equivalent manner, be formed by a proton exchange membrane cell called PEM cell. The electrolyte may be the effluent to be treated. However, it is preferable to use an independent and controlled electrolyte, such as baking soda to avoid incompatibilities between the electrode and the electrolyte, and parasitic chemical reactions. Generally, the electrodes are each arranged in a compartment of the electrolysis device. Preferably, the hydrogen electrode is disposed at a level higher than the level of the oxygen electrode. The electrode compartments are separated from each other by a porous partition on its lower half and sealed on its upper half. The oxygen electrode compartment is provided with a vent for venting oxygen into the atmosphere and the hydrogen electrode compartment communicates with the recirculation circuit via a radial tube. recirculation circuit and disposed downstream of the throat of said recirculation circuit, this tube opening into said compartment of the hydrogen electrode or in a space communicating with said compartment. The presence of a vent allows simple and rapid removal of oxygen which is toxic to the catalyst. Such a device is able to self-regulate. The hydrogen gas produced accumulates in its compartment and dries said electrode so that the production of hydrogen is interrupted until a sufficient quantity of hydrogen gas is evacuated. In a variant, the reducing agent supply device is a formic acid supply device. In this case, the formic acid feed device comprises a formic acid reservoir, a pump, preferably peristaltic, formic acid supply of the recirculation circuit from said reservoir, a pH meter capable of measuring the pH recirculation circuit and control means of the pump according to the data provided by said pH meter.

Of course, a mixed solution combining the reducing agent supplying devices described above can also be envisaged. Preferably, the evacuation chamber is provided with gas / liquid separation means, such as a baffle, compartmentalizing said evacuation chamber in at least one upstream compartment and a downstream compartment, for overflow circulation of said compartment. upstream to the downstream compartment, and the pumping means have a suction inlet disposed in the downstream compartment below the overflow overflow area.

The overflow overflow makes it possible to eliminate a portion of the gases from the flow of fluid circulating inside the reactor. These gases can be captured inside a foam disposed in the circuit of the flow of fluid flowing in the discharge chamber of the reactor. Inside this foam, the gas bubbles agglutinate and rise to the surface of the contents of the chamber by flotation. Preferably, the feed chamber of the reactor supplied with fluid flow by the recirculation circuit furthermore comprises a fluid flow supply inlet independent of the outlet of the recirculation circuit in said chamber, and the pumping means comprise two outputs, one supply of the recirculation circuit, the other discharge of the fluid flow outside the reactor. Although the effluent to be treated may be the fluid directly supplying the reactor, and in particular the fluid flow supply chamber of said catalyst, a solution in which a fluid stream capable of being enriched with anions contained in the effluent to be treated to feed the reactor is preferred. In this case, the inlet of the reactor feed chamber, independent of the outlet of the recirculation circuit, and the outlet of the flow of fluid outside the reactor are each connected to a modification plant of the reactor. the mineralization of the effluent to be treated, such as an electrodialyzer. Preferably, the electrodialyzer comprises, arranged inside an enclosure, at least two electrodes and a plurality of anionic and cationic membranes arranged alternately delimiting between them two series of cells, each cell of said first series of cells being provided with a fluid inlet and a fluid outlet, the fluid inlets being in communication with a fluid distributor and the fluid outlets opening into a fluid manifold, the fluid distributor being connected to the outlet, 20 of fluid flow discharge outside the reactor, the fluid collector being connected to the fluid flow supply inlet, the reactor feed chamber, each cell of the second series of cells, provided with an inlet and a fluid outlet, being able to be supplied with effluent to be treated. Preferably, the electrodialyzer comprises a probe for measuring the concentration of dissolved total salts of the effluent generally expressed by measuring the conductivity in pS / cm and means for inverting the polarity of the electrodes according to the data. provided by said measuring probe. It is thus possible to use the electrodialyzer as a means of demineralization or dilution of the effluent to be treated and of mineralization or concentration of the flow of fluid flowing inside the reactor. The mineral concentration of the flow of fluid circulating inside the reactor is thus chosen as high as possible for optimum operation of the catalyst while maintaining an acceptable mineral concentration range in the effluent to be treated. Moreover, the presence of an electrodialyzer allows non-ionized molecules, in particular organic compounds and colloids to remain in the effluent to be treated without these latter entering the reactor because they can be toxic to the catalyst. The electrodialyzer supplied with effluent to be treated may comprise, upstream of its inlet, a device for filtering said effluent. The invention also relates to a method for treating an aqueous effluent charged with nitrogenous chemical species by means of an installation of the aforementioned type, said method comprising a step of electrodialysis of said effluent to charge a flow of fluid flowing through the the interior of said anionic electrodialyser from said effluent, a step of supplying the reactor comprising the catalyst with the flow of fluid loaded with anions from said effluent, a step through which the catalyst passes through the fluid flow, a recirculation step of a portion of said fluid stream from the catalyst inside the reactor in parallel with a step of evacuating the other part of the fluid flow to the electrodialyzer and a step of supplying gaseous hydrogen and / or Formic acid of the recirculating fluid stream. The invention will be better understood on reading the following description of exemplary embodiments, with reference to the appended drawings in which: FIG. 1 represents a schematic sectional view of an installation according to the invention; FIG. 2 represents a schematic view of the hydrogen gas supply device of the recirculation circuit; FIG. 3 represents a schematic view of the formic acid feed device of the recirculation circuit; Figure 4 shows a schematic view of the reactor discharge chamber.

As mentioned above, the plant 1, object of the invention, is more particularly intended for the treatment of aqueous effluent E loaded nitrogenous chemical species, such as aquarium water, fish farming or other. This treatment is carried out using a catalyst 3 comprising at least two metals M, M 'on a porous support. This catalyst may be a bimetallic catalyst M-M '. In this case, M is a group VIIIA metal, M 'is a metal having an oxidation potential E0 (MIn + / M1) of less than 0.8 V / ERH and 80% of the atoms of the metal M' are part of particles bimetallic in which the atomic ratio M '/ M is equal to the overall atomic ratio M' / M of the catalyst.

Preferably, the total amount of metal M and metal M 'fixed on the support is between 0.5 and 5% by weight. The atomic ratio M '/ M is between 0.8 and 1.1. The total quantity of bimetallic catalyst introduced into the reaction medium is greater than 0.2 g. The metal M is platinum or palladium. The metal M 'is selected from the group consisting of Cu, Ag, Sn and Ge. The porous support is alumina, a silica or a silico-aluminate. Preferably, the bimetallic catalyst is a Pt / Cu on alumina catalyst obtained by catalytic reduction of a copper solution with hydrogen in the presence of a Pt / Al 2 O 3 catalyst. An example of manufacture of such a catalyst is described in particular in patent FR-2,798,375. In another embodiment of the invention, the porous support catalyst is a XYMgAl-shaped catalyst where X is at least one noble metal selected from Pd, Pt, Ru, Ir and Rh, Y is at least a non-noble metal selected from Cu, Sn, Zn, In, Ni, Ag, Fe or Co, Mg is magnesium and Al is aluminum. An example of such a catalyst is described in EP-1,466,664. The installation comprises: - a reactor 2 in the form of an enclosure comprising the catalyst 3, a fluid feed catalyst chamber 4, a chamber 5 for evacuating the flow of fluid from said catalyst, said catalyst 3 being disposed between said supply and discharge chambers 4, - pumping means 6 shown here inside the evacuation chamber 5 and able to recirculate part of the fluid flow from the evacuation chamber 5 towards the feed chamber 4 of the reactor 2 and a device 7 for supplying gaseous hydrogen and / or formic acid to the recirculation circuit 16. The reactor fluid feed chamber 4 comprises at least two fluid inlets, one formed by the outlet 41 of the recirculation circuit 16 in said chamber, the other via a flow supply inlet 42. of fluid connected to an electrodialyzer 20. The evacuation chamber 5 is provided with means 19 for gas / liquid separation formed here by a baffle of the partition type compartmenting said chamber 5 into an upstream compartment 25 and a downstream compartment taken in the direction of circulation of the fluid flow inside said reactor 2. The flow of fluid from the upstream compartment of the evacuation chamber 5 passes above said partition which does not extend to the ceiling of the chamber to penetrate in the downstream compartment. This downstream compartment of the evacuation chamber 5 houses the pumping means 6 and a cellular material, such as a foam, responsible for retaining most of the gases contained in the circulating fluid stream. These gas bubbles agglutinate before rising to the surface of said compartment while the rest of the fluid flow is pumped by said pumping means 6. The pumping means 6 thus have a suction inlet 61 and two outlets shown at 62 and 63 in the figures. The outlet 62 feeds the recirculation circuit 16 of the fluid flow reactor while the outlet 63 is an outlet for discharging the flow of fluid outside the reactor 2. This outlet 63 of the flow of fluid flow is here shown connected to an electrodialyzer 20 to which the reactor feed chamber is connected at the inlet. In particular, the electrodialyzer comprises, disposed inside an enclosure 21, two electrodes 22, 23, namely an electrode preferably stainless steel or titanium and a carbon or graphite electrode or any other material conductive and weakly resistant, a plurality of alternately anionic and cationic parallel membranes 24 delimiting between them two series of parallel cells represented for the first series of cells at 25 and for the second series of cells at 25 '. The membranes are water-impermeable and cation-permeable for cationic membranes and anions for anionic membranes in the presence of an electric field. Conventionally, in such an electrodialysis device, during the action of the electric field, the anionic membranes allow the passage of anions and the cationic membranes pass the cations. The anions thus leave cells 25 'of the second series of cells inside which the effluent to be treated circulates to accumulate inside the cells of the first series of cells, these cells of the first series of cells being able to supply the reactor 2 with fluid flow. All the nonionized molecules and the colloids remain in the E effluent. The whole of the electrodialyzer is thus formed of an alternation of dilution or demineralization cells and of concentration or mineralization cells which make it possible to enrich minerals the flow of fluid flowing inside said cells. Each cell 25 of the first series of cells, lined with an anionic membrane and a cationic membrane, is provided with a fluid inlet 26 and a fluid outlet 27, the fluid inlets 26 being in communication with each other. a fluid distributor 28 and the fluid outlets 27 opening into a fluid manifold 29, each cell 25 'of the second series of cells, provided with an inlet and a fluid outlet, being capable of being fed with effluent E to treat. In the example shown, the fluid manifold 29 and the fluid distributor 28 of the electrodialyzer are each formed of horizontal tubes generally disposed outside the chamber of the electrodialyzer. In the example shown, the electrodialyzer comprises three cells 25 supplied with fluid flow by the fluid distributor 28 and opening into the fluid manifold 29. These cells 25 are each separated by a cell 25 'through which the effluent to be treated flows from the inlet towards the outlet of said cell. These circulation cells of the effluent to be treated are here four in number. The distributor 28 is supplied with fluid by the pump pumping means 6 of the plant, the outlet 63 for discharging fluid flow outside the reactor is connected to said distributor 28. The fluid collector 29 of the reactor The electrodialyzer is connected to the inlet 42 for supplying fluid flow to the feed chamber 4 of the reactor 2. A loop circulation is thus established between the reactor and the electrodialyzer. The electrodialyser 20 comprises a probe 30 for measuring the concentration of dissolved total salts of the effluent and means for inverting the polarity of the electrodes 22, 23 as a function of the data provided by said measurement probe 30. It thus becomes possible to concentrate the flow of fluid flowing in the cells of the first series of cells inside the electrodialyzer or to maintain inside this flow of fluid a substantially constant mineral concentration to allow optimal operation. catalyst. Thus, by way of example, it is considered in FIG. 1 that the electrode 23 (right electrode) is the cathode and the electrode 22 (left electrode) is the anode and that the positive membranes permeable to the anions form the right wall of the first cells 25. In this configuration, the flow of fluid flowing in the first series of cells 25 is enriched at least in anions to form a concentrate of nitrogen anions. If the polarity of the electrodes 22 and 23 is reversed, the flow of fluid flowing in the first series of cells 25 can no longer be concentrated into anions. In addition to the circuit for recirculating the flow of fluid between the reactor and the electrodialyser, the installation comprises a circuit 16 for recirculation internal to the reactor as mentioned above. This recirculation circuit 16, which makes it possible to reintroduce part of the flow of fluid leaving the evacuation chamber of the reactor 2 into the feed chamber 4 of the reactor 2, is associated with a device 7 for supplying a reducing agent. formed of either hydrogen gas or formic acid. This feed device 7 is here shown disposed above the discharge chamber 5 of the reactor. When the supply device 7 is a hydrogen gas supply device, this device communicates with the recirculation circuit 16 at a zone of the recirculation circuit 16 disposed downstream of a throat 17 fitted to said circuit 16. recirculation to allow, by venturi effect, a supply of the recirculation circuit 16 hydrogen gas.

In the example shown, the device 7 for supplying gaseous hydrogen is formed by an electrolysis device comprising two electrodes 8, 9 able respectively to produce one of hydrogen and the other of oxygen. . The electrodes 8, 9 are each disposed in a compartment 10, 11 of the electrolysis device. The compartment 11 of the oxygen electrode 9 is provided with a vent 12 for venting oxygen in the atmosphere and the compartment 10 of the hydrogen electrode 8 communicates with the recirculation circuit 16 via a radial tube 18 to said recirculation circuit 16 and disposed downstream of the throat 17 of said recirculation circuit 16. This tube 18 opens into said compartment 10 of the hydrogen electrode 8 or in a space communicating with said compartment 10.

It is the hydrogen gas produced by one of the electrodes which regulates the production of hydrogen by drying said electrode more or less depending on the amount of gas present in the electrode compartment. with hydrogen. The two compartments are separated by a watertight partition 13 over part of its height, in this case its upper half. Both compartments are surmounted by an electrolyte tank 14 formed here by baking soda. The hydrogen gas thus produced is sucked by the venturi effect in the recirculation circuit of the reactor and ensures optimum operation of the catalyst. Alternatively or additionally, the feed device may be a formic acid feed device. In this case, the formic acid supply device (see FIG. 3) comprises a formic acid reservoir 31, a pump 32, preferably peristaltic, for supplying formic acid to the recirculation circuit 16 from said reservoir 31. a pH meter 33 capable of measuring the pH of the recirculation circuit 16 and the control means of the pump 32 according to the data provided by said pH meter 33. In this case of operation, the pH is maintained between 4 and 6 5. Of course, the installation comprises conventionally, a control unit for managing at least the operation of the electrodialyzer, reactor pumping means, the peristaltic pump when present, and the power supply. different electrodes. This control unit is conventionally an electronic unit and / or computer processing and calculation. Said unit may be in the form of an electronic circuit provided with a microcontroller or a microprocessor associated with a data storage memory. Said unit is able, from input data from the sensors, such as the aforementioned probe, or from stored data, to output control signals from the means of the plant, as described above. . The operation of an installation as described above is therefore as follows. The effluent E to be treated is introduced into the electrodialyzer 20 through a flow inlet disposed generally in the upper part of the enclosure of said electrodialyzer. This effluent circulates inside the second series of cells 25 'of said electrodialyser from the inlet to the outlet of each of the cells of this second series of cells. During this crossing, the effluent is demineralized. The anions, in particular the NO2- and NO3- ions of said effluent pass through the anionic membranes impermeable to water but permeable to said anions of the cells 25 'and penetrate into the cells 25. The situation is similar for the cations. The flow of fluid contained in said first series of cells 25 thus concentrates in anions. This flow is fed via the fluid collector 29 of the electrodialyzer into the fluid flow supply chamber 4 of the reactor 2. Under the action of the pump 6 of the reactor 2, this fluid flow passes through the catalyst 3 enters the upstream compartment and then the downstream compartment of the reactor 5 discharge chamber 2. Part of the fluid flow is discharged through the outlet 63 of the pumping means to the fluid distributor 28 of the electrodialyzer which re-supplies by the inputs 26 each cell 25 of the first series of cells of the electrodialyzer while the other part of the fluid stream recirculates inside the reactor 2 and feeds, through the inlet 41, the feed chamber 4 of the reactor 2. During this recirculation, the recirculating fluid flow inside the reactor is charged with hydrogen gas or formic acid via the feed device 7 disposed on said recirculation circuit 16 . The effluent to be treated circulates continuously in the electrodialyzer to allow a controlled and continuous supply of the fluid reactor to be treated.

Claims (10)

REVENDICATIONS1. Installation (1) for treating an aqueous effluent (E) charged with nitrogenous chemical species, using a catalyst (3) comprising at least two metals M, M 'on a porous support, the first metal M being chosen among platinum (Pt), palladium (Pd), ruthenium (Ru), iridium (Ir), rhodium (Rh), the second metal M 'being selected from copper (Cu), tin ( Sn), zinc (Zn), indium (In), nickel (Ni), silver (Ag), iron (Fe) or cobalt (Co), germanium (Ge), characterized in that said plant (1) comprises a reactor (2) comprising said catalyst (3) arranged between a fluid supply catalyst chamber (4) (3) and a fluid flow evacuation chamber (5) from said catalyst (3), pumping means (6) adapted to recirculate a part of the fluid flow from the evacuation chamber (5) towards the supply chamber (4) and a device (7) supplying gaseous hydrogen and / or acid form of the recirculation circuit (16). 2. Installation (1) according to claim 1, characterized in that the device (7) for supplying gaseous hydrogen communicates with the recirculation circuit (16) at a zone of the recirculation circuit (16) disposed in downstream of a throat (17) equipping said recirculation circuit (16) to allow, by venturi effect, a supply of the recirculation circuit (16) hydrogen gas. 3. Installation (1) according to one of claims 1 or 2, characterized in that the device (7) for supplying gaseous hydrogen is formed by an electrolysis device comprising two electrodes (8, 9) capable of producing respectively, one, hydrogen, the other, oxygen. 4. Installation (1) according to claim 3 taken in combination with claim 2, characterized in that the electrodes (8, 9) are each disposed in acompartment (10, 11) of the electrolysis device, in that the compartment (11) of the oxygen electrode (9) is provided with a vent (12) for venting oxygen to the atmosphere and in that the compartment (10) of the hydrogen electrode (8) communicates with the recirculation circuit (16) via a tube (18) radial to said recirculation circuit (16) and disposed downstream of the throat (17) of said recirculation circuit (16), this tube (16) 18) opening into said compartment (10) of the hydrogen electrode (8) or into a space communicating with said compartment (10). 5. Installation (1) according to one of claims 1 to 4, characterized in that the formic acid feed device comprises a reservoir (31) of formic acid, a pump (32), preferably peristaltic, d supply of formic acid to the recirculation circuit (16) from said reservoir (31), a pH meter (33) capable of measuring the pH of the recirculation circuit (16) and pump control means (32) in according to the data provided by said pH meter (33). 6. Installation (1) according to one of claims 1 to 5, characterized in that the chamber (5) discharge is provided with gas / liquid separation means, such as a baffle, compartmentalizing said chamber (5) in at least one upstream compartment and one downstream compartment for overflow circulation from said upstream compartment to the downstream compartment, and in that the pump means (6) have a suction inlet (61) arranged in the downstream compartment below the overflow overflow area. 7. Installation (1) according to one of claims 1 to 6, characterized in that the chamber (4) for supply of the reactor (2) supplied with fluid flow by the recirculation circuit (16) further comprises a inlet (42) supply fluid flow independent of the outlet (41) of the recirculation circuit (16) in said chamber (4), and in that the means (6) for pumping comprise two outlets (62, 63) , one (62) for supplying the recirculation circuit (26), the other (63) for discharging the flow of fluid outside the reactor. 8. Installation (1) according to claim 7, characterized in that the inlet (42) of the reactor supply chamber (4) (2) independent of the outlet (41) of the recirculation circuit (16) and the outlet (63) discharging fluid flow outside the reactor are each connected to an installation for modifying the mineralization of the effluent (E) to be treated, such as an electrodialyzer (20). 9. Installation (1) according to claim 8, characterized in that the electrodialyseur (20) comprises, disposed within an enclosure (21), at least two electrodes (22, 23) and a plurality of membranes (24) alternating anionic and cationic members delimiting between them two series of cells (25, 25 '), each cell (25) of said first series of cells being provided with a fluid inlet (26) and an outlet (27), the fluid inlets (26) being in communication with a fluid distributor (28) and the fluid outlets (27) opening into a fluid manifold (29), the fluid distributor (28) being connected to the fluid flow outlet (63) outside the reactor, the fluid manifold (29) being connected to the fluid flow supply inlet (42) of the chamber (4). ) of the reactor (2), each cell (25 ') of the second series of cells, provided with an input and an output fluid, being able to be supplied with effluent (E) to be treated. 10. Installation (1) according to claim 9, characterized in that the electrodialyzer (20) comprises a probe (30) for measuring the concentration of dissolved total salts of the effluent and polarity inversion means of the electrodes (22,23) according to the data provided by said measuring probe (30).