WO2002012138A1

WO2002012138A1 - Installation and method for purifying waste water or effluents in particular industrial

Info

Publication number: WO2002012138A1
Application number: PCT/FR2001/002533
Authority: WO
Inventors: Abderrazack Djenani
Original assignee: Abderrazack Djenani
Priority date: 2000-08-07
Filing date: 2001-08-02
Publication date: 2002-02-14
Also published as: FR2812627B1; AU2001284104A1; FR2812627A1

Abstract

The invention concerns a method whereby an effluent (A) is first neutralised and then subjected to an aerobic biological treatment and a process of evaporation in a first bioreactor (1) whereof the content is subjected to a physico-chemical treatment which separates water from sludge. The treated water (12) is then subjected to a filtering treatment where all its remaining impurities are eliminated while the remaining skimmed sludge (13) is transferred to a second bioreactor (2), an effluent (B) having slower biodegradation than that of effluent (A) and the retentate (24) derived from the filtering are subjected to an aerobic biological treatment and an evaporation process in a second bioreactor (2). The content of the bioreactor (2) is then subjected to a sludge treatment. The sludge is then treated for its conditioning while the residual water (17) of the bioreactor (2) is directed to the first bioreactor (1) to complete its biodegradation. The invention is of particular interest for builders of purifying stations and industries producing polluting waste.

Description

[INSTALLATION AND PROCESS FOR THE PURIFICATION OF WASTE OR RESIDUAL WATERS, ESPECIALLY INDUSTRIAL

The present invention relates to a process for the continuous purification of waste or residual water, in particular industrial water, and to the installation necessary for its implementation in a purification station.

The term used water, effluent or discharge means any waste of urban or industrial origin in the form of an aqueous solution. Such water usually requires prior treatment in a treatment plant before it can be discharged into a watercourse or reused as it is in industrial installations.

In various activity sectors, and in particular in the chemical, pharmaceutical, agrochemical, metallurgical, electronic or in that of surface treatments, textiles or pulp, industries consume a lot of water and generate quantities significant wastewater. For the latter, global water management is a primary necessity.

Due to strict regulations which impose on polluting industries the treatment of their waste water before discharge, the treatment of industrial water is of vital economic importance for the industry and several solutions have been considered. Conventionally, wastewater treatment can be done in two different ways which are sometimes combined.

The first method consists of a physicochemical treatment during which chemical additives are added to the wastewater in order to coagulate the impurities present in it. After decantation, the coagulated impurities settle at the bottom of a decanter or a settling tank and form sludge while the purified water can be transferred or reused. However, the sludge is heavily loaded with impurities and therefore difficult to recover. which results in high costs for further processing. In addition, the purification rates obtained by this treatment method are limited.

The second method consists of a biological treatment during which the wastewater is admitted at regular rate into a basin containing an endogenous bacterial fauna capable of breaking down the polluting molecules. The size of the basin is conditioned by the time necessary for bacteria to digest the polluting molecules and a decanter then separates the biological sludge from the treated water. However, in industries, the effluents are often very complex and come from several workshops. These discharges, once mixed and diluted often limit the yield of the biological treatment plant, for example due to the presence of a non-precipitable chemical oxygen demand (COD) and / or biological inhibitors which harm the functioning and efficiency of biomass.

The choice of treatment method depends on the biodegradability ratio of the effluent. According to the prior art, when the two processes are combined, the physico-chemical treatment always comes upstream from the biological treatment and traditionally, the effluents are mixed and diluted but not dissociated. Having to pay heavy taxes depending on the degree of pollution of water discharged into the environment, industries are looking for an optimal ratio between the cost of treating wastewater and the rate of purification of the latter, the ideal being for them to fully recycle their effluents and not to reject anything.

Process improvements pre-existing have been realized but none fully meets the needs of the industry. In addition, these improvements cannot always be adapted to preexisting installations, which involves many additional costs, and these improvements generally involve a significant additional occupation of the ground, which is extremely penalizing when the available space is reduced. In addition, conventional treatment methods often require difficult maintenance, which results in considerable loss of time and money.

Finally, they do not produce recyclable water of constant quality over time and therefore do not meet the most demanding industrial needs. However, provision has been made to overcome this defect by using a membrane treatment, but this process often encounters problems of clogging of the membranes due to too high pollutant loads which lead to too high costs due to the hydraulics (strong decrease permeability, too frequent cleaning cycles ...).

Consequently, it follows from the preceding remarks that the current effluent treatment methods do not always give satisfaction to the industries.

In order to meet the current requirements of the industry and to overcome the defects of the prior art raised above, the object of the present invention is threefold.

A first object of the invention is to provide a reliable, economical and practical process for rational and progressive purification depending on the discharges from the industrial site and the legislative constraints of one or more different effluents according to their degree of biodegradability. This process should be easily implemented continuously with optimal treatment capacity and simplified maintenance while limiting the production of waste such as sludge. A second object of the present invention is to provide a secure and modular device, with simplified maintenance and having a low occupancy of the ground for its implementation in order to be able to easily adapt it to existing effluent treatment installations if necessary. and to increase their yield.

Finally, a final object of the present invention is to provide a process and an installation capable of transforming waste water of all kinds into recyclable water, of constant quality, allowing the manufacturer to ultimately minimize the overall cost of water ( make-up and recycling) and completely free oneself from its environment (zero rejection).

The method according to the invention makes it possible to simultaneously treat two effluents each having a different degree of biodegradability and collected separately at the source. In the context of the present description, the second effluent (effluent B) has a slower biodegradation than that of the first effluent (effluent A). .

One or the other or each of the effluents A and B is or are constituted (s) in unit form or of a mixture of effluents of the same general characteristics. According to this process, the effluent A is first neutralized, then undergoes an aerobic biological treatment and an evaporation process in a first bioreactor. After treatment in this first bioreactor, its content undergoes a physico-chemical treatment which separates the water from the sludge. The resulting water then undergoes a physical treatment in particular by filtration, for example tangential of the type membrane, by which it is rid of its last impurities while the sludge from the physico-chemical treatment, effluent B and the retentate (concentrate * of impurities) from the separation treatment undergo an aerobic biological treatment and a process of evaporation in a second bioreactor. Continuously or periodically, a determined volume of the content of this second bioreactor is then subjected to a sludge treatment. The latter are treated for conditioning while the residual water from the treatment in this second bioreactor is directed to the first bioreactor.

This invention advantageously makes it possible to adapt the purification process to the nature of the effluents to be treated and to treat them simultaneously according to their degree of biodegradability.

Other characteristics and advantages of the invention will appear on reading the following description made with reference to FIG. 1 which represents the diagram of an example of installation with an at least first bioreactor 1 and with at least a second bioreactor 2, installation intended to implement the method according to the invention.

After a possible prior neutralization of the pH of an effluent A using at least one device 3 for diffusing neutralizer into the liquid and using a device 4 for absorbing the neutralizer, this effluent A is transferred to the at least first biological reactor 1 hereinafter called bioreactor 1. This bioreactor 1 is made of a suitable material. Its dimensions are defined as a function of the volume of the effluent to be treated, of the time necessary for endogenous or exogenous bacteria, selected and sown with nutrients at determined frequencies and quantities, to digest the polluting molecules and according to variations in volume and pollutant load of the effluent. In this bioreactor 1, the effluent A is brought to a temperature of about 20 to 30 ° C by means for example of a coil-type heat exchanger and continuously agitated using a stirring device. 5.

In order to implement the evaporation and oxygenation process, a quantity of air produced by one or more compressor (s) 6 is, for example, permanently injected into the bioreactor 1 by one or more ramp (s) d ventilation 7 through fine nozzles.

The quantity of compressed air blown depends on the volume of the bioreactor 1 and of the effluent A It allows the latter to evaporate. This oxygenation, necessary for the maintenance and development of endogenous or exogenous bacteria specific to effluent A ensuring the degradation of the biodegradable compounds contained in this effluent A, also allows the oxidation of certain polluting compounds and maintains a permanent evaporation of this effluent.

This step ensures the biodegradation of dissolved and particulate pollution.

In a variant of the embodiment of the invention, it is envisaged to subject the compressor (s) ^' 6 to dissolved oxygen and redox probes which can be located in biological reactors 1 and 2 for limit energy consumption, rather than using permanent air diffusion.

Preferably on a daily basis, but also possibly continuously, a determined volume of effluent from the biological reactor 1 passes through a physico-chemical treatment module comprising several compartments, in order to allow the molecules of effluent A, dispersed in the solutions of the compartments (8, 9, 10 and 11) and partially degraded, to be added with chemicals, for example products from the company AQUAPROX marketed under the brand AQUAPROX MFC 3300, 8590, 8700 for coagulants of mineral and organic cationic type and the brand AQUAPROX MFA 8220 E for anionic flocculants , which coagulate them into water insoluble flocs.

These flocs are raised to the surface of the water by blowing, for example, pressurized water. Thus, the fine air bubbles are fixed on the flocs and entrain them towards the surface of the water. The upper volume is preferably removed by mechanical skimming, thus separating the treated water 12 from the skimmed sludge 13 made up of polluting molecules, particles and bacteria.

In this phase, by thus eliminating a good part of the biomass developed in the biological reactor 1, the efficiency of the remaining biomass is favored while limiting the growth of the biomass which is always generating biological sludge. This characteristic allows a significant reduction in the production of sludge.

In a variant of this preferred embodiment, the modularity of the process makes it possible to install the membrane processing unit at this stage of the process. However, at this level of treatment, in certain effluents, the concentrations of mineral salts

(sodium, sulfate, chloride and the like) and in non-biodegradable organic molecules (hard COD) are too important for the membrane treatment, by tangential filtration and can lead to a strong decrease in the permeability of the membranes.

In this case, the membrane processing unit by tangential filtration must be placed further in the process.

The skimmed liquid sludge 13 is transferred through a conduit 14 to the at least second bioreactor 2 while the treated water 12 can be directed to a storage tank 18 while waiting to undergo the physical separation treatment for example by tangential filtration of membrane type and according to the technique known as concentration by higher pressure in order to rid this treated water 12 of its last impurities.

In order to limit or avoid the precipitation of salts in the membranes, it may be advantageous to inject mineral-type sequestrants, for example sodium hexametaphosphate (HMP) which can be used with acid to avoid, for example, the precipitation of calcium carbonate (C _a C0 ₃ ) in the storage tank 18, upstream of the membrane treatment by tangential filtration, or of organic type such as the products marketed under the brands "PERMATREAT 391", KEMAZUR DE 47 "," HYPERSPERSE AF200 "or even" FLOCON 135 and 260 ".

Preferably, the final treatment for the separation of ions from water molecules will be a membrane treatment by tangential filtration, in particular reverse osmosis by concentration, which is the membrane separation technique having the lowest molecular weight cut-off threshold. . This preferred technology has the advantage of separating water molecules from dissolved salts, inorganic molecules and organic molecules with a molecular weight between 10 and 100 Daltons and retaining molecules of a few Angstrδ s (10 ^{~ 7} mm) and monovalent salts under a working pressure up to 80 bars. However, depending on the nature of the liquid to be treated and the use of the treated water to recycle, it is possible to replace the reverse osmosis unit with other membrane techniques, namely: microfiltration, ultrafiltration, nanofiltration or by frontal filtration processes using submerged or separate membrane modules with or without permeate suction such as the process developed under the brand name "BIOSEP" by the company "OTV" or those, identical, developed by the company "ZENON" or the process "PLEIADE" developed by the company "RHODIA".

Other electro-membrane techniques can advantageously complement them. two aerobic biological treatments of effluents such as membrane electrolysis, electrodialysis and / or ion exchange resins (REI). It is also possible to replace the final treatment by tangential membrane filtration with a finishing treatment carried out by adsorption on activated carbon in powder (CAP) or in grains (CAG) or any similar finishing process for example of the biofilter type and / or all gravity separation process. It is also possible to use an electro-chemical separation treatment.

Membrane treatment by tangential filtration is carried out when the physico-chemical parameters of the water impose it, in particular as regards residual COD, conductivity, and other similar parameters, for the purpose of recycling the treated water during of the industrial process. The filtration installation comprises at least pipes or conduits for the circulation of the water to be treated, a pressurizing pump (20 to 80 bars) either volumetric or centrifugal, a recirculation pump, the module or modules reverse osmosis (flat modules, tubular modules, spiral modules or hollow fiber modules), an expansion valve or an energy recovery turbine, devices for regeneration and cleaning of the membranes, a heat exchanger which makes it possible to maintain the water to be treated at the desired temperature, one. or several upstream and downstream storage tanks as well as all the measuring devices and necessary controls (pressures, flow rates, speed, temperature ...). Its operation takes place according to various processes, in particular by batch or batch process, by continuous recycling process or by continuous process.

The use of ^' tangential membrane filtration at the end of the purification process makes it possible, on the one hand, to eliminate the clogging problems generally encountered in the presence of too high pollutant loads and the inevitable consequences of loss of effectiveness of the treatment linked to this clogging phenomenon, and on the other hand, to develop a particularly efficient treatment in order to obtain quality water, perfectly meeting the requirements of an industrial process and which the biological treatment supplemented by the physical treatment does not allow -chemical. Advantageously, this additional membrane treatment makes it possible, for example, to eliminate non-recipitable COD, suspended matter, microorganisms or chlorides, in order to produce recyclable water, of constant quality over time and which can meet the most demanding criteria. more selective of an industrial process.

A supply pump 19 supplies a concentration tank 20 with treated water 12 coming from the physico-chemical treatment and which has been stored in the storage tank 18. With the aid of a recirculation pump 21, this treated water 12 passes under pressure in a casing module made of a suitable material comprising the membrane filtration modules 22 of organic or mineral type, chosen according to their selectivity, their cut-off threshold, their degree of porosity, their shape, their surface and conditions for their application, such as, for example, membranes made of carbon fiber composites sold by the company CARBONE LORRAINE, or even tubular ceramic membranes. Preferably, the permeate 23 (that is to say the water freed of its impurities) which is the transmembrane flow is permanently evacuated to a storage tank 25. An outlet or supply pump 26 directs it then towards the outside for example towards the industrial process installations while the retentate 24 (that is to say the impurity concentrate) which is the tangential flow returns to the concentration tank 20 and is periodically evacuated towards the or the bioreactor (s) 2.

The sludge from the skimmed sludge 13 (concentrate of impurities and biomass) is brought to and stored in the biological reactor 2.

Advantageously, this biological reactor 2 is designed to receive an effluent B which may consist of several effluents of the same general characteristics, the biodegradation of which is slower than that of effluent A which may also consist of several effluents of the same general characteristics.

The sizing of this bioreactor 2 made of suitable material is conditioned by the volume of the effluent B to be treated, by the time necessary for its biodegradation, as well as by the volume of the liquid sludges from the physico-chemical treatment and by the amount of retentate. produced by the membrane process by tangential filtration by concentration loop of the tangential flow (retentate or concentrate of the pollutant load separated from the water under a pressure of up to 80 bars).

As in the case of the bioreactor 1, the bioreactor 2 will include a stirring device 5 and aeration-oxygenation device 7 and a means for bringing the effluent B to temperature, for example a coil type heat exchanger.

According to a preferred mode where the biological reactor 2 operates at high volume load and at high mass load, to ensure and accelerate aerobic or anaerobic biodegradation of effluent B and where it is brought to a temperature of about 35 to 70 ° C, its internal face may present thermal and anti-corrosion protection, as by example of PTFE known under the name TEFLON. The heating of reactor 2 can for example benefit from a recovery of the calories of the industrial process and, combined with the permanent injection of compressed air, it allows a significant evaporation of the effluent without atmospheric pollution.

The permanent or intermittent oxygenation in the biological reactor 2 ensures the oxidation of the organic and inorganic compounds of the effluent B. This range of temperatures in which the preferred working temperature is found in the biological reactor 2 guarantees the permanent elimination by lysis of microorganisms. This characteristic makes it possible to reduce the volume of biological sludge. This working temperature also allows odor control.

Due to the working temperature and pressure, it is also possible to cause the precipitation of mineral salts contained in the effluents. These salts, evacuated here with the sludge can no longer precipitate in the tangential filtration membranes, which makes it possible to gain in efficiency of permeability and to save cycles of regeneration and cleaning of the membranes. Effluent B, stirred and aerated in the reactor

2, is mixed there with the liquid sludge 13 coming from the physico-chemical treatment which, progressively, biologically inactivates but remains chemically active for the absorption and / or adsorption of the pollutants of this effluent B, in particular the heavy metals often present in industrial waste waters and which are in the form of divalent cations. This characteristic also makes it possible to trap volatile organic compounds and polluting vapors during evaporation, which makes it possible to carry out this evaporation continuously without generating atmospheric pollution. Thus, by using for example an injection of compressed air of the order of 130 m ³ per hour through fine nozzles, at the abovementioned temperatures, it is possible to evaporate approximately 10 m ³ of effluent per day. A higher temperature of 5 ° C with an air injection of 180 m ³ per hour allows an evaporation of about 25 m ³ of effluent per day.

The evaporation caused in biological reactors 1 and 2 allows an optimization of the process according to variations in the volume and the polluting load of the incoming flow. In other words, it makes it possible to adapt this treatment system to the evolution of discharges from the industrial site.

Continuously or preferably periodically, a determined volume of the contents of reactor 2 is directed to a device for treating biological sludge

(amalgams of biological sludge and pollutants) comprising for example a neutralization tank 15 and a compression and mechanical dehydration unit 16 and / or a centrifuge. In this system, the sludge is conditioned and stored and then removed off site to be treated and recovered.

The resulting treated water 17 coming from the treatment of and with biological sludge in the bioreactor 2, is redirected to the biological reactor 1 to be mixed there with the effluent A and to be treated therein biologically. A large quantity of pollutant molecules of effluent B having been digested during the stay in the biological reactor 2, after dewatering and / or separation by centrifuge of the biological sludge, this effluent B can join 1 effluent A without consequence on the biomass developed in the biological reactor 1 to complete its biodegradation.

For general reasons of warming up and maintaining the quantity of sludge injected at their inlet temperature and ensuring gradual homogenization and uniformization between the liquids entering one and / or the other bioreactors, the bioreactor (1) and / or (2) present (s) in (x). high injection point (s) of the deflection structures which isolate them and slow down the injected liquids before they are mixed with the ambient medium. These deflection structures may be upper interior compartments open transversely or by their bottom to be located after a certain difference in height downward relative to the corresponding injection point, in communication with each other and with the internal volume of the corresponding bioreactor. The method according to the invention is intended to be easily adapted to any type of industry requiring purification of waste water. It relates to the chemical, pharmaceutical, agrochemical, metallurgical, electronic, that of surface treatments, textiles or pulp, as well as all industries generally consuming water and generating waste water. In its complete configuration, this process is particularly suitable for treating the five-day biochemical oxygen demand (BOD5), suspended solids (MES), the chemical oxygen demand (COD) and the chemical demand for soluble oxygen. , non-biodegradable and non-precipitable (hard COD).

It is also possible to provide for the application of the method according to the invention for the production of drinking water, for example from surface water in order to eliminate micro-pollutants such as pesticides. more and more frequent in this type of water, organic matter and substances generating taste and odor, ammonia, mineral salts and pathogenic germs such as bacteria, viruses and pathogenic proteins for example prion type. This process can also be adapted to the treatment of industrial or urban wastewater consisting of a single effluent and can be applied to the treatment of seawater. It must be understood that, in this case, it is the same effluent which arrives at the entrance to bioreactor 1 and at the entrance to bioreactor 2.

Depending on the type of pre-existing treatment plant, it is also planned to adapt the process described without departing from the scope of the invention, in particular by applying the membrane device in place of the physicochemical treatment, for example when the nature and pollution load of the discharges do not require very extensive treatment.

According to this variant, it is possible to design a tangential filtration unit of the membrane type with two stages capable of operating at the same pressure or at different pressures, for example reverse bi-osmosis, bi-icrofiltration, bi-ultrafiltration, bi-nanofiltration, operating in a loop, one stage of which will be connected to bioreactor 1 operating at a pressure for example of 20 bars with evacuation of the retentate (concentrate of impurities mixed with biomass) to bioreactor 2 while the treated water ( permeate) is stored for recycling in the industrial process, and a second stage operating at a pressure for example of 40 bars or more, coupled to the bioreactor 2 with evacuation of the permeate to the bioreactor 1 and / or to the storage 18 of treated water 12 for recycling, and the retentate or concentrate of impurities to a centrifuge-type separation unit, the residual separation water of which will be transferred to bioreactor 1.

The operation of such an installation may be carried out in a batch or batch process, in a continuous recycling process or in a continuous process.

Many other variants and improvements of the process described can also be envisaged without departing from the scope of the invention. One can for example, equip the installation upstream of the biological reactors 1 and 2 with filtration pre-treatment devices, physical separation and / or adsorption of the activated carbon column type or any other. Likewise, it is possible to carry out aerobic or anaerobic biological pretreatment of effluent B in one or more specific bioreactor (s) upstream of bioreactor 2.

Likewise, a coagulation / flocculation station can be provided upstream of the sludge treatment unit to improve the hydraulic performance of the treatment system.

It is also possible to envisage the injection into the biological reactor 1 of any product capable of ensuring the fixation of the biomass and / or of adsorption, such as for example activated carbon (PAC) sold under the brand PICAFLO HP.

Anaerobic or strict anaerobic treatment in the biological reactor 2 can represent an advantageous alternative for the treatment of effluents.

Operation is also possible at normal effluent temperatures without generating evaporation.

In addition, the tangential filtration unit, ^for example membrane, has been selected for its adequacy with the needs of the installation, but it is possible to replace it by any process. alternative to ensure the physical separation of ions from water molecules as indicated above and / or filtration or finishing.

The design of the tangential filtration unit ^• Membrane example can also be performed to generate specific water to industrial processes, including the production of deionized water, sterile water or the like.

In addition, in at least one of the biological reactors, preferably in the biological reactor 2, it is possible to use carbon dioxide (C0 ₂ ) in the supercritical state (temperature above 31 ° C and pressure above 74 bars ) which may have advantageous characteristics for dissolving organic compounds.

Finally, it can be envisaged to provide in the installation, purges, sampling stations, pre-filtration devices, probes, on-line analyzers and detection and alarm systems, operating and control devices for pressure, speed, temperature, fluid, sound level and a heat exchanger and an expansion valve for the tangential membrane filtration unit. We can automate the operation of the installation and manage it remotely by remote monitoring.

The installation can also include a post-treatment to restore the physico-chemical balance of the treated water, for example a carbon-carbon balance.

Effluents A and B can also come from different places, for example for one, from an urban wastewater collection and for the other, from an industrial site.

Claims

1. A process for the continuous purification of waste or residual water, in particular industrial water, from two effluents A and B collected separately at the source, the degree of biodegradability of which is different from each other, B being less biodegradable than A, with a view to producing clean water of constant quality, possibly recyclable and / or potable, characterized in that the effluents A and B are treated in parallel separately and simultaneously respectively in an at least first bioreactor (1) and in at least a second bioreactor ( 2), in that the effluent A is first neutralized then undergoes in the bioreactor (1) an aerobic biological treatment at the same time as an evaporation allowing the optimization of the process, that after this treatment, a sample is taken volume of effluent in this bioreactor (1) to pass it through a physico-chemical treatment module which separates the treated water (12) from the sludge (13), this treated water (12) being very transferred to a storage unit (18) from which it is removed to undergo filtration in a filtration unit while the skimmed sludge (13) from the physico-chemical treatment and consisting of impurities and biomass are immediately transferred to at least one bioreactor (2) designed to receive and simultaneously treat effluent B, the biodegradation of which is slower than that of effluent A and in which this effluent B undergoes at least one biological treatment and one evaporation allowing an optimization in function variations in the volume and the pollutant load of the incoming flow, and then at least one treatment of the sludge by physical separation (15-16) in which the resulting residual water (17) is redirected to the bioreactor (1) to complete its biodegradation by endogenous or exogenous bacteria from effluent A.

2. Purification process according to claim 1 characterized in that the elimination of dissolved and particulate pollution of effluents A and B is carried out in the bioreactors (1) and (2), in the physico-chemical treatment module, in the biological sludge treatment unit and in the filtration unit.

3. Purification process according to claim 1 or 2 characterized in that the effluent B undergoes at least two aerobic biological treatments, one in the bioreactor (2) and the other in the bioreactor (1), a treatment extraction of biological sludge and pollutants, a physico-chemical treatment and a physical separation finishing treatment.

4. Purification process according to claim 1 or 2 or 3 characterized in that permanently or periodically eliminates an amount of volume in the two bioreactors (1) and (2) by evaporation and by extraction of impurities and biomass from the physico-chemical treatment and the treated water (12) resulting from the physico-chemical treatment is discharged by transfer to a filtration unit and by evacuation of the biological sludge from the bioreactor (2).

5. Purification process according to claims 1 to 4 characterized in that evaporation in the two bioreactors (1) and (2) is caused by the diffusion of pressurized air through fine nozzles and by the temperature of the effluents.

6. Purification process according to claim 1 characterized in that the effluent A or B is composed of several effluents with the same characteristics.

7. Purification process according to claim 1 characterized in that the filtration is tangential filtration.

8. Purification process according to the preceding claim characterized in that the tangential filtration is of the membrane type. .

9. Purification process according to claim 8 characterized in that the tangential filtration of the membrane type is carried out discontinuously or in batches, by simple continuous process or by recycling.

10. Purification process according to claim 8 or 9 characterized in that the transmembrane flow is removed.

11. Purification process according to any one of claims 7 to 10 characterized in that the tangential flow is returned to a concentration tank (20) and that periodically, it is transferred to the bioreactor (2).

12. Purification process according to claim 7 or 8 characterized in that the concentration of the retentate is produced by a concentration loop of the tangential flow.

13. Purification process according to claim 8, characterized in that the tangential membrane filtration is of the double-stage type, one stage of which is connected to the bioreactor (1) and preferably operates at a pressure of 20 bars with evacuation of the retentate towards the bioreactor (2) while the permeate is stored for recycling in the industrial process, and a second stage of which preferably operates at a pressure of 40 bars or more, coupled to the bioreactor (2) with evacuation of the permeate to the bioreactor (1) and / or to the storage tank for the treated water for recycling, and the retentate or concentrate of impurities to a centrifuge-type separation unit whose residual separation water is transferred to the bioreactor ( 1).

14. Purification process according to the preceding claim characterized in that the tangential filtration operates in a loop according to different pressures by reverse osmosis or bi-microfiltration, or bi-ultrafiltration, or bi-nanofiltration.

15. Purification process according to claim 12 or 13 characterized in that the tangential filtration operates at the same pressure for each of the stages.

16. Purification process according to claim 1 characterized in that the filtration of the final treatment of the water resulting from the physicochemical treatment is a frontal filtration of membrane type.

17. Purification process according to claim 1 characterized in that the biological reactor (2) operates at high volume load and at high mass load to ensure and accelerate the biodegradation of effluent B.

18. Purification process according to any one of the preceding claims, characterized in that the sludge from the second reactor (2) is conditioned in a sludge conditioning device (15, 16).

19. Purification process according to the preceding claim, characterized in that the conditioning of the sludge comprises a neutralization step coming after the biological treatment and a step of separation and mechanical dehydration or centrifugation.

20. Purification process according to any one of the preceding claims, characterized in that it comprises a step of neutralizing the pH of the first effluent A in a device for neutralizing the pH (3, 4) and in that the stage of neutralization of the pH of the first effluent A takes place before the biological treatment of purification of this effluent A.

21. Purification process according to any one of the preceding claims, characterized in that the biological treatment. carried out in reactors (1) and (2) comprises aerobic biological treatment, aeration, agitation and evaporation.

22. Purification process according to any one of claims 1 to 20, characterized in that the treatment of effluent B in the biological reactor (2) is an anaerobic or strict anaerobic treatment.

23. Purification process according to any one of the preceding claims, characterized in that the biological treatment in the reactor (1) is carried out at a temperature of about 20 to 30 ° C.

24. Purification process according to any one of the preceding claims, characterized in that the biological treatment in the reactor (2) is carried out at a temperature of about 35 to 70 ° C.

25. Purification process according to any one of the preceding claims, characterized in that the biological treatment in the reactor (1) and / or the reactor (2) is carried out at normal effluent temperatures.

26. Purification process according to any one of the preceding claims, characterized in that the working temperature in the bioreactor (2) is such that the skimmed sludge (13) resulting from the physico-chemical treatment and transferred into the bioreactor (2 ) are gradually biologically inactivated by ther olysis but remain chemically active for the absorption and adsorption of heavy metals contained in effluent B, volatile organic compounds and polluting vapors of effluent B.

27. Purification process according to any one of the preceding claims, characterized in that the physico-chemical treatment is carried out downstream of the bioreactor (1) and comprises the addition of chemicals in this effluent which coagulate the polluting molecules and the biomass of this effluent in large flocs insoluble in water, these flocs being brought up to the surface of the water by blowing pressurized water and removed from the upper volume by mechanical skimming, thus separating the water (12) skimmed sludge (13), an amalgam of polluting molecules and biomass.

28. Purification process according to the preceding claim characterized in that the elimination of an amount of biomass developed in the bioreactor (1) promotes the efficiency of aerobic biological treatment in this bioreactor (1) while significantly reducing the volume sludge.

29. Purification process according to the preceding claim, characterized in that the biodegradation of the effluent B is accelerated by the addition in the bioreactor (2) of biomass originating from the bioreactor (1) and resulting from the physicochemical treatment.

30. Purification process according to any one of the preceding claims, characterized in that sequestrants and / or acid are injected into the effluent stored in the tank 18 before its filtration treatment.

31. Process for the continuous purification of industrial waste water according to any one of the preceding claims, characterized in that carbon dioxide (C0) in the supercritical state is injected into the bioreactor (2).

32. Purification process according to any one of the preceding claims, characterized in that the effluents A and B come from the same effluent.

33. Purification process according to claim 1 characterized in that the mineral salts contained in the effluents of the bioreactors (1) and (2) are precipitated which are thus removed with the sludge.

34. Purification process according to claim 1 characterized in that the biomass is fixed and the polluting compounds are adsorbed by activated carbon powder CAP.

35. Method according to any one of the preceding claims, characterized in that the flows entering one and / or the other of the bioreactors are isolated from each other with a view to their uniformization and progressive homogenization.

36. Installation for the treatment and depollution of industrial waste water receiving and treating two effluents A and B, effluent B having a slower biodegradation than that of the first effluent A, characterized in that it makes it possible to implement the method according to any one of the preceding claims.

37. Installation according to the preceding claim, characterized in that the physico-chemical treatment module which separates the water from the sludge comprises several compartments, a device for adding chemicals to the effluent to be treated in order to coagulate the molecules of 1 effluent and the biomass in large flocs insoluble in water, in that it comprises a device for bringing these flocs to the surface of the water by blowing pressurized water and a mechanical skimming device for evacuate the upper volume, thus separating the water (12) from the skimmed sludge (13).

38. Installation according to any one of the preceding claims 36 or 37, characterized in that the aeration and evaporation devices comprise one or more compressor (s) (6) for produce air, and one or more rail (s) of ventilation (7) comprising fine through which air nozzles is injected into the liquid contained in ^'each of the bioreactors.

39. Installation according to the preceding claim, characterized in that the compressor (s) (6) are controlled by dissolved oxygen and redox probes which are located in the biological reactors (1) and (2).

40. Installation according to any one of claims from 36 to 39, characterized in that it includes pre-treatment devices, in particular biological, physical or physicochemical.

41. Installation according to any one of claims from 36 to 40, characterized in that it comprises a coagulation / flocculation station upstream of the sludge treatment unit.

42. Installation according to any one of the preceding claims from 36 to 41, characterized in that it comprises electro-membrane devices for treating the water resulting from the physicochemical treatment.

43. Installation according to any one of the preceding claims from 36 to 42 characterized in that it comprises means for carrying out a finishing treatment by adsorption on activated carbon in powder (CAP) or in grain (CAG) of water. treated (12) resulting from the physico-chemical treatment.

44. Installation according to any one of the preceding claims from 36 to 41 characterized in that a biofilter and / or gravity separation means provide a finishing treatment for the treated water (12) resulting from the physico-chemical treatment.

45. Installation according to any one of the preceding claims from 36 to 41, characterized in that it comprises means for subjecting the treated water (12) resulting from the physico-chemical treatment to a electro-chemical separation treatment.

46. Treatment and depollution installation according to any one of the preceding claims from 36 to 41, characterized in that it comprises a frontal filtration unit of membrane type for the final treatment of the water resulting from the physico-chemical treatment.

47. Installation according to any one of the preceding claims from 36 to 46 characterized in that the bioreactor (s) comprise deflection structures at the entry points of the flows entering their internal ambient environment.

48. Installation according to any one of claims 36 to 47, characterized in that it is automated and / or managed remotely by remote monitoring.

49. Installation according to any one of claims 36 to 48, characterized in that it comprises a post-treatment to restore the physico-chemical balance of the treated water.