BREWING SYSTEM, BIOREACTOR PROVIDED WITH SUCH A SYSTEM AND IMPLEMENTATION METHOD THEREOF

Abstract

Said brewing system is intended to be fitted to a bioreactor which can be used in particular in milk and cheese factories, fermented dough production units, breweries, wine-making units or even low-temperature fermentation units in an aerobic or anaerobic environment, in particular lacto-fermentation units for the purpose of preserving vegetables, wastewater treatment stations, fish farming ponds with or without temperature control. According to the invention, said brewing system comprises:—at least one flexible and sealed brewing chamber (2, 3),—means (4) for receiving a fluid referred to as the filling fluid,—means (5, 51, 70, 71) for transferring the filling fluid between the brewing chambers (2, 3), and means (4) for receiving the filling fluid as well as varying the volume of the filling fluid admitted into each brewing chamber.

Claims

1-18. (canceled)

19. A brewing system, comprising: at least one flexible and sealed brewing chamber, each brewing chamber operable to be totally or partially submerged in a reaction volume of a bioreactor; a filling fluid chamber to receive a filling fluid in a manner such that an outer volume of each brewing chamber is variable according to the volume of filling fluid admitted into the filling fluid chamber; and a closed fluid circuit to transfer and circulation of the filling fluid between the brewing chambers and the filling fluid chamber, the closed fluid circuit being operable to vary the volume of the filling fluid admitted into each brewing chamber.

20. The brewing system of claim 19, wherein the filling fluid comprises a heat transfer liquid or water.

21. The brewing system of claim 19, wherein the closed fluid circuit is operable to increase the volume of the filling fluid in a first brewing chamber of the at least one flexible and sealed brewing chamber, while reducing the volume of the filling fluid in a second brewing chamber of the at least one flexible and sealed brewing chamber, then reduce the volume of the filling fluid in the first brewing chamber while increasing the volume of the filling fluid in the second brewing chamber.

22. The brewing system of claim 19, wherein each brewing chamber in the at least one flexible and sealed brewing chamber comprises an inner skin and an outer skin, the outer skin having a high resistance with respect to aggressive liquids and materials characteristic of a reaction species, while the inner skin has a lower resistance with respect to the filling fluid.

23. The brewing system of claim 22, wherein the outer skin is provided with a coating formed by fibres distributed to form a flexible mat that is operable to promote a fixing of bacterial biomass in the brewing chamber.

24. The brewing system of claim 19, wherein the closed fluid circuit comprises, for each brewing chamber: a first pipe which allows flow of the filling fluid from the filling fluid chamber towards the at least one flexible and sealed brewing chamber, and a second pipe which allows an exit of the filling fluid from the at least one flexible and sealed brewing chamber towards the filling fluid chamber.

25. The brewing system of claim 19, wherein: the filling fluid chamber comprises a reservoir for storing the filling fluid, and the reservoir includes a heater for heating the filling fluid.

26. The brewing system of claim 19, further comprising a temperature control unit operable to control a temperature of the filling fluid and maintaining a temperature of the reaction volume in a suitable range of temperature values.

27. The brewing system of claim 19, wherein each brewing chamber has a maximum outer volume of between 1 and 10 cubic metres.

28. The brewing system of claim 19, wherein further comprising a fluid circuit control unit, operable to control the closed fluid circuit.

29. The brewing system of claim 19, wherein further comprising a fastening device operable to fasten each brewing chamber with respect to walls of a tank of the bioreactor and a bottom thereof.

30. The brewing system of claim 29, wherein the fastening device comprises a rigid frame operable to maintain reinforced borders in sealed contact with the bottom and the walls of the tank to prevent any substantial intrusion of matter or of liquid under the brewing chamber.

31. The brewing system of claim 19, further comprising a gas injector operable to inject a pressurised gas, of a biogas or carbon dioxide type, to ensure micro-oxygenation tangential to an outer surface of each brewing chamber.

32. The brewing system of claim 19, wherein the brewing system is arranged in a bioreactor implemented in milk and cheese factories, fermented dough production units, breweries, wine-making units, low-temperature fermentation units in an aerobic or anaerobic environment, lacto-fermentation units for preserving vegetables, wastewater treatment stations, and fish farming ponds with or without temperature control.

33. The brewing system of claim 32, wherein the brewing system is operable to allow stirring of reaction species that are admitted into a reaction volume of the bioreactor.

34. A bioreactor, comprising: at least one tank defining a reaction volume; an input device operable to input a reaction species which are capable of participating in a biochemical reaction inside the reaction volume; an output device operable to output products of the biochemical reaction; and a brewing system operable to stir the reaction species that are admitted into the reaction volume, the brewing system including: at least one flexible and sealed brewing chamber, each brewing chamber operable to be totally or partially submerged in the reaction volume; a filling fluid chamber to receive a filling fluid in a manner such that an outer volume of each brewing chamber is variable according to the volume of filling fluid admitted into the filling fluid chamber; and a closed fluid circuit to transfer and circulation of the filling fluid between the brewing chambers and the filling fluid chamber, the closed fluid circuit being operable to vary the volume of the filling fluid admitted into each brewing chamber.

35. A method for operating a bioreactor of claim 34, the method comprising: admitting the reaction species into the reaction volume; admitting the filling fluid into at least one brewing chamber; conducting a transfer of the filling fluid towards the at least one brewing chamber and/or out of the at least one brewing chamber, to vary an outer volume of the at least one brewing chamber and thereby brew the reaction species.

36. The method of claim 35, wherein the filling fluid is admitted at a temperature greater than a temperature of the reaction species.

37. The method of claim 35, wherein at least three stable values, including a minimum value, an intermediate value, and a maximum value, are assigned to the volume of each brewing chamber.

38. The method of claim 35, further comprising: conducting at least one elementary brewing cycle by: increasing a volume of the filling fluid in a first brewing chamber up to a maximum value, while reducing a volume of the filling fluid in a second brewing chamber until a minimum value; reducing the volume of the filling fluid in the first brewing chamber until a minimum value, while increasing the volume of the filling fluid in the second brewing chamber up to a maximum value; and repeating at least one elementary cycle when necessary.

Description

DRAWINGS

[0102] The invention will be described below, in reference to the appended drawings, given only as non-limiting examples, in which:

[0103] FIG. 1 is a diagram, illustrating the various elements forming a bioreactor that is equipped with a brewing system according to the invention.

[0104] FIG. 2 is a diagram, analogous to FIG. 1, illustrating a first step of implementation of the above bioreactor.

[0105] FIG. 3 is a diagram, analogous to FIG. 1, illustrating a second step of implementation of the above bioreactor.

[0106] FIG. 4 is a diagram, analogous to FIG. 1, illustrating a third step of implementation of the above bioreactor.

[0107] FIG. 5 is a diagram, illustrating on a larger scale a part of a flexible chamber belonging to the above brewing system.

DESCRIPTION

[0108] The bioreactor illustrated in the drawings, which is designated as a whole by the reference I, comprises first of all a tank 1. In the example illustrated, this is a single chamber but, as will be shown below, it is possible to use several tanks mutually placed in communication. The wall 10 of this tank defines a reaction volume V1. For this purpose, input means 11 are provided allowing the admission of reaction species, which are capable of participating in a reaction of the biochemical type inside this reaction volume.

[0109] Moreover output means 12 allow to evacuate, out of the reaction volume, the substrates digested in a substantially complete manner during the reaction. In a manner known per se, these output means can communicate towards separation means, of the conventional type, which allow to separate a solid fraction and a liquid fraction. Moreover the tank is provided with a roof 13, allowing to collect a gaseous fraction of the reaction, in particular biogas. These structural elements 10 to 13 are not part of the invention, so that they will not be described in more detail below.

[0110] In the example illustrated, the wall 10 of the tank defines a single reaction compartment. However, as an alternative not shown, it is possible for this wall to define several compartments. In this respect it is advantageous for the architecture of these compartments to allow the creation and the maintaining of a bioturbation zone. Such an architecture can, for example, be according to the teaching of the French patent 3 045 594 in the name of the applicant.

[0111] The bioreactor further comprises a brewing system according to the invention, which allows to stir the reaction species admitted into the reaction volume, according to a swell movement, the frequency and the amplitude of which are variable and controllable. As will be shown below, this brewing system is capable of conferring suitable dynamics onto the desired biochemical reaction.

[0112] According to an essential element of the invention, this brewing system comprises first of all at least one brewing chamber, of the flexible and sealed type. The example illustrated uses two distinct chambers 2 and 3 of this type with it being understood that, as will be described in detail below, a different number of chambers can be used.

[0113] Flexible and sealed chambers are already known from the prior art, for example from the French Patent Publication No. 2 787 438. In this document each chamber comprises an envelope, which is formed by an inner skin intended to contain water, or an equivalent liquid in terms of aggressivity parameters. Moreover this envelope comprises an outer skin, the resistance of which is clearly higher than that of the inner skin, since this outer skin is intended to come into contact with liquids, the aggressivity of which is significantly greater.

[0114] According to the invention, each chamber 2 and 3 has a structure, of which it can be said that it is inverted with respect to the prior art described in the preceding paragraph. This difference is illustrated schematically in FIG. 5, which shows the envelope 20 of the chamber 2, with it being understood that the envelope 30 of the chamber 3 is identical. In substance this envelope 20 is composed of an inner skin 25, which is intended to come in contact with a filling fluid. Advantageously, this filling fluid is a heat transfer liquid, typically water or an equivalent liquid in terms of aggressivity parameters and density. Consequently, this inner skin has a relatively low resistance to aggressions.

[0115] However, the outer skin 26 of this envelope 20 is intended to come in contact with much more aggressive fluids, in particular aggressive organic effluents. Consequently, it has a resistance to aggressions that is much greater than that of the inner skin 25. This outer skin 26 is advantageously provided with a coating 27, shown schematically, which is formed by fibres referred to as free and short, the rigidity of which is variable. These fibres are distributed so as to form a flexible mat, capable of favouring the fixing of bacterial biomass in the tank.

[0116] Besides the above difference, the manufacturing of these chambers 2 and 3 is substantially identical to that of the chambers of the prior art, in particular described in the French patent above. The envelopes 20 and 30 are typically composed of special cloths made of woven plastic fibres, generally coated with PVC polyvinyl chloride. These envelopes are assembled in a manner known per se, by any suitable means, in particular by being welded and sewed.

[0117] These chambers have mechanical features, which are capable of making them resistant to high external pressures. In this respect, they can in particular resist stresses exerted by agricultural machines. As non-limiting examples, they can have a resistance to a water-gauge pressure of 8 m maximum, or 0.8 bar. Besides this mechanical resistance, these envelopes are capable of resisting over a long term relatively high temperatures, which are those occurring in the context of the implementation of methane digesters.

[0118] These chambers can adopt a wide range of geometric alternatives, which confers onto them a possibility of adaptation in tanks having different architectures. For example mention will be made of an orthogonal geometry, of the type square, rectangle or right-angled triangle. Mention will also be made of a geometry in the shape of a disc, or of a portion of a disc.

[0119] Because of their flexible nature, these chambers 2 and 3 are capable of adopting, in a stable manner, different sizes. When they are inflated in a maximum manner, their size can be between 1 and 10 cubic metres. The limitation of volume is more particularly linked to the flow rates of the pumps that supply them, which must be relatively high to ensure the swell movement required for effective brewing. Moreover, at least one other configuration of a smaller size can be provided. In the example illustrated, each chamber is capable of having a size referred to as minimum which corresponds for example to approximately one third of the maximum size, as well as a size referred to as intermediate which corresponds for example to approximately two thirds of the maximum size.

[0120] Beyond the constraint of dimensioning of the pumps that serve these chambers, the dimensional parameterisation of the chambers depends substantially on the volume of the tanks, their diameter, the tank-bottom surface, but especially on the height of the column of digestates in the tanks. These constraints fall under the technical feasibility of the method, so that the most sensible and the least costly solution for getting around these constraints is to prefer inflatable chambers of a small size disposed side by side. In this respect, the maximum dimension of each chamber does not exceed a voltage of approximately 10 m.sup.3.

[0121] Advantageously, each chamber is fastened onto the tank 10. Preferably, there is a system for fastening onto the bottom 14 of the tank. This fastening system, which is schematically illustrated while being assigned the reference 16, is of any suitable type. In this respect, it can for example be chosen to use a tubular frame anchored at the tank bottom by bolts that pass through the peripheral margin of the chambers. Moreover, it is also possible to use a similar fastening system but installed on the lateral wall 15 of this tank. The fastening of the chamber, with respect to the tank, allows to avoid the possible flotation of this chamber. This phenomenon can in particular occur when the weight of the chamber, inflated with the filling liquid, is less than that of the reaction species contained in the digester. This fastening further allows to deploy the chamber in a satisfactory manner, during the various implementation phases, while preventing the interference of digestates between the tank bottom and the brewing chambers.

[0122] The brewing system according to the invention further comprises a drum 4, allowing the reception of the filling liquid, intended to supply the chambers 2 and 3. This drum 4 is placed under heat exchange, by an exchanger 40 of any suitable type, with a reserve 41 containing a heat transfer fluid, typically hot water. For this purpose a line 42, equipped with a solenoid valve 43, extends between this reserve 41 and this exchanger 40. Downstream of this exchanger, an additional line 44 ensures the recycling of all or part of the heat transfer fluid, in the direction of the reserve 41. This reserve is of any suitable type, known per se: mention will be made in a non-limiting manner of the heating tank of a bain-marie, a boiler supplied with biomethane or biogas, a solar thermal or mixed photovoltaic and thermal plant, a passive system for recovering the heat on the walls of a composting silo in a thermophilic zone, or any combination of the devices listed immediately above.

[0123] The brewing system according to the invention further comprises means for transferring the filling liquid, mentioned above. The drum 4 is first of all placed in communication with each chamber, by this filling liquid. For this purpose, a main intake line 5 extending immediately downstream of the drum, which opens into branch intake lines 50 and 51, each of which is connected to the inner volume of a respective chamber, is provided. The main line 5 is equipped with a temperature sensor 52 of any suitable type, as well as with a flowmeter 53. Moreover, each branch line is equipped with a respective solenoid valve 54, 55.

[0124] A pump 6 is further provided, allowing to move the filling liquid along the lines 5, 50 and 51. Advantageously this pump 6 is capable of moving the filling liquid which can reach a temperature of 60° C. with a parameterisation of barometric pressure adapted to the configuration of the flexible chambers on the following basis (without inferring head losses): [0125] Dp=(Vi−Vm)/T, where Dp is the nominal flow rate of the pump given in m.sup.3/h, Vi is the intermediate volume of a flexible cistern, Vm is the minimum volume of a flexible cistern and T the duration expressed in hours chosen to go from the state Vm to the state Vi, and [0126] Pp=((ρ.Math.Hs)/10).Math.1.25, where Pp is the nominal service pressure of the given pump in bar (10 m water-gauge) (with a prudence factor of 1.25) that the pump must deliver, ρ is the density of the digestates, Hs the height of the column of digestates above the surface of the submerged inflatable drums in the stage Vm.

[0127] Moreover, various pipes allow the return of the filling liquid, from each chamber 2 and 3 towards the drum 4. For this purpose, two branch lines referred to as return are connected onto the envelopes of the chambers. These branch lines 70 71 open into a return line referred to as main, which is placed in communication with the drum 4. Each branch line 70 71 is equipped with a solenoid valve 72 73, as well as with a decompression valve 74 75. Moreover, the main line 7 is equipped with a flowmeter 76, as well as with a solenoid valve 77.

[0128] As shown above, the various branch lines 50,51 70 71 are connected onto the envelopes of the brewing chambers. The mechanical connection of these lines, at these envelopes, is carried out in a manner known per se. For example, the solution described in the aforementioned French Patent Publication No. 2 787 438 can be used.

[0129] The parameterisation of the pump is also dependent on the maximum and minimum volume of the chambers which determines the amplitude of their variation in volume and on the frequency of this variation which is expressed in terms of flow rate. Thus for a chamber of 1 m.sup.3 maximum filling and 0.25 m.sup.3 minimum filling, or a total theoretical amplitude of 0.75 m.sup.3 with a frequency of 30 s or 0.03 Hz the flow rate of the pump should be calculated as follows.

[0130] The real amplitude to be taken into account is (0.75 m.sup.3+0.25 m.sup.3)/2 since when the filling liquid of the first chamber empties into the second chamber under the effect of the pressure of the reaction species contained in the bioreactor the equilibrium is reached when each chamber contains 0.5 m.sup.3. The pump must therefore mobilise 0.25 m.sup.3 to bring the filling of the second chamber to 0.75 m.sup.3. The placement into equilibrium via gravity, without pumping can take 10 seconds and if it is desired for the transfer to take 30 seconds. The pump must therefore mobilise 0.25 m.sup.3 in 20 seconds or 45 m.sup.3/h. The pumping can also occur during the phase of gravitational balancing which substantially shortens the duration of this phase.

[0131] Finally the brewing system according to the invention advantageously comprises control means, which include first of all a control unit 8, shown schematically. This unit is first of all in communication, via a line 81, with a temperature sensor 80, which is submerged in the reaction volume of the tank. Moreover, this control unit 8 is connected, via respective lines 82 and 83, to the flowmeters described above. Finally this unit 8 is capable of controlling the various solenoid valves described above, via control lines that are not shown.

[0132] An example of implementation of the bioreactor 1 equipped with a brewing system according to the invention, as described above, will now be presented, in particular in reference to FIGS. 1 to 4.

[0133] The reaction species are first admitted into the reaction space, via the pipe 11. Moreover, each chamber 2 and 3 is filled via filling liquid, via the successive lines 5, then 50 and 51. The instant at which the initial filling is carried out is globally not important, since this is a system with continuous feeding.

[0134] First it is supposed that, as shown in FIG. 1, each chamber is filled approximately halfway, so as to adopt the intermediate configuration presented above. It is then supposed that, according to the invention, it is desired to carry out a brewing of the reaction species initially admitted into the inner volume V1. The brewing is sequenced in amplitude and in frequency in a robot, and a brewing session can last up to 20 minutes for example.

[0135] For this purpose, this means varying the respective sizes of the two chambers. The transfer means, belonging to the brewing system of the invention, are capable of varying the volumes of filling fluid in the two chambers. Advantageously this volume increases in the first chamber while it decreases in the second chamber, and vice versa.

[0136] In substance, as shown in FIG. 2, the solenoid valves respectively 55 and 72 are closed. This allows to prohibit the flow of filling liquid, on the one hand towards the inside of the chamber 3, on the other hand towards the outside of the channel 2. It is understood that, in these conditions, the chamber 2 tends to fill up, until it adopts its maximum size. First, this chamber reaches a phase of equilibrium with the other chamber, via gravity, then continues to fill up under the effect of the pump. Moreover, the chamber 3 tends to empty itself, until it adopts its minimum size.

[0137] Then, the reverse operation is carried out, namely the solenoid valves 55 and 72 are once again opened while, according to the sequence programmed in the robot, the solenoid valves 54 and 73 are closed. This thus allows to prohibit the flow of filling liquid both into the chamber 2 and out of the chamber 3 while allowing this flow into the chamber 3 and out of the chamber 2. In these conditions, the chamber 2 tends to empty itself, until it adopts its minimum size, while the chamber 3 tends to fill up, until it adopts its maximum size. This configuration is illustrated in FIG. 3.

[0138] It is possible to carry out a repetitive implementation of the elementary cycle described in detail above, namely to make the chambers 2 and 3 go several times in an alternating manner successively into their configurations of FIGS. 2 and 3. These phases of deployment and of retraction of the chambers confers a brewing effect referred to as pulsed, at the bottom of the tank. This induces a positive displacement, also ensuring the thermal transfer with a weak gradient of the digestates received in this tank.

[0139] The use of the inflatable chambers, according to the invention, is very particularly advantageous. Indeed, the brewing thus carried out is substantially non-destructive to the bacterial biomes. Moreover, it is likely to advantageously disturb, both upward and downward in incident curved fallout, the digestates over the entire column. This guarantees the desired swell effect at tank bottom, with effects being transferred throughout the tank. This swell effect is very particularly significant when at least two brewing chambers are used. It is noted that such an effect cannot be obtained, by implementing the teaching of the Chinese document presented above, given that the latter uses a single chamber.

[0140] Finally a transfer of thermal energy is advantageously carried out, according to the invention, via the necessary rise in temperature of the reaction species. This thermal transfer can be controlled, via the control unit. According to the temperature measured by the sensor submerged in the tank, the control unit is capable of controlling the various solenoid valves, so as to make the filling liquid transit into a heat exchanger, inside of which it will be loaded with calories to meet the needs for transfer of these calories in the bioreactor.

[0141] In this respect, the use of a heat transfer liquid as filling fluid allows to ensure two functions simultaneously in an efficient manner, namely the brewing but also the thermal transfer. It is noted that the teaching of the Chinese document above does not allow to carry out these combined functions in a satisfactory manner, given that the filling fluid used is air. However, the latter clearly has worse performance than a liquid, in terms of thermal transfer.

[0142] With regard to the Chinese document, it is also emphasised that it does not mention important factors, which are advantageously taken into account in the present patent application. On the one hand the aggressivity of the digestates for the outer surface of the envelopes, on the other hand the impermeability to water for their inner face, constitute limiting parameters, particularly critical when the volume of the envelope must be varied. However, such parameters are not clearly addressed in this Chinese document.

[0143] According to the invention, the combination of the addition of organic substrates rich in digestible carbon, the dilution of the entering substrates carried out with solutions rich in intensifiers of the bacterial metabolism and this pulsed brewing which also produces a very efficient inertial thermal regulation favours the maintaining of a bioturbation zone in a tank of the digester.

[0144] Indeed, the solid carbon matter, the raw compost, has a low density that maintains it at the surface, the solutes for dilution and for metabolic intensification, the composting percolates close to the density of water are present throughout the volume of the tank while the denser mineral coenzymes rapidly migrate to tank bottoms.

[0145] The pulsed brewing creates a swell movement, the frequency of which is low, but the amplitude of which is significant and which is weakly turbulent. This swell movement, obtained according to the invention, is particularly effective since it adopts the form of a positive-displacement flow coming from the middle of the tank, with emergence of a digestate lens at the centre of the surface of the tank. This leads to the hydraulic collapse of the digestates floating at the periphery and towards the bottom, without the densest fraction being driven towards the top of the tanks but rather maintained at the bottom regardless of the movement of the digestates. These dynamics prevent in particular the formation of a stable floating crust at the surface of the tanks. They further maintain a certain fluidity as well as a reduced coalescence at tank bottom, which is advantageous with a view to a regular extraction by pumping of undesirable sediments.

[0146] Indeed the dense and solid matter with a small particle size but non-colloidal rapidly constitutes at tank bottom a fixing base for dominant bacterial colonies and their symbiotes, commensals and competitors. The minerals, bones, nails, beaks, cartilage, but also bark or fragments of wood form most of these fixing grains. The slow brewing maintains dynamics of exchange in this zone rich in fixed biomass, the bioturbation effect is thus perfectly ensured.

[0147] This tank bottom architecture is certainly favourable to the fixing of active biomass. However, through accumulation, it tends to reduce the reaction volume in the bioreactor. It must consequently be advantageously regulated, via regular extractions.

[0148] The method for implementing the brewing system and the bioreactor that are according to the invention has a remarkable effectiveness, which is based on major factors of maintaining and activating bioturbation mechanisms. The latter comprise the mechanism of biochemical enrichment by partial recycling in the digester of the composts and composting percolates, the maintaining of the tank at optimal temperature with an inertial vector with a weak thermal gradient which also ensures the maintaining at a temperature relatively higher in the bioturbation zone with respect to the rest of the column, as well as the pulsed brewing combined with micro-oxygenation by recirculation of the biogas purified of H.sub.2S.

[0149] The reaction process occurring in the tank can be of any suitable type, namely of the infinitely mixed or multiphase type, with continuous or sequential loading, with free or fixed biomass, mesophilic or thermophilic. Moreover, the invention can be applied to reactions involving all possible ranges of concentration of volatile organic solids.

[0150] As the reaction takes place, the biogas produced is extracted via the roof 13. For reasons of economy and simplification of the automation of the brewing process, a sharing of the heating, pumping, flow rate regulation and thermal transfer means is implemented. In substance, each bioreactor tank receives, as dedicated equipment, only pipes and solenoid valves. This induces that the brewing carried out in a bioreactor tank is organised in a session with a limited duration. In this respect, a duration of 20 minutes is a good period for methane digesters including 3 bioreactor tanks. Indeed, this allows to leave a tank without brewing with swell effect for approximately 40 minutes, which is a time interval easily tolerable on the biochemical level, in particular if oxygenation is maintained during this period.

[0151] Advantageously, the brewing chambers can be used in their configuration referred to as overflowing. For this purpose, as shown in FIG. 4, the 2 chambers 2 and 3 are filled, so that they adopt at the same time their maximum size. It is thus understood that, in these conditions, the sum of the volumes occupied by the chambers and the substrates becomes greater than the volume of the tank. Consequently, a part of the substrates is evacuated by the lines 12, so as to be separated into a liquid fraction and a solid fraction.

[0152] A person skilled in the art can vary in various manners the size of the chambers 2 and 3, according to the time. According to a first possibility not shown, the brewing sequence can comprise several alternating phases of filling then of emptying, for each chamber. Of course other types of variations can be provided, according to that which is desired by a person skilled in the art.

[0153] In the example illustrated, for reasons of dynamics of the fluids and thermodynamics, 2 independent inflatable chambers are used inside the same tank. However, as an alternative, for example in a multiphase digester, it is possible to install a single chamber per tank, in particular if the tank considered corresponds strictly to one phase and if its size is sufficiently small. In the latter case, it is possible for example to provide several tanks disposed next to each other, operating via overflowing.

[0154] In general, a succession of two to three inflatable drums of a small size disposed side by side is preferable to any other arrangement. In this configuration the brewing is thus carried out without it being necessary to have available an adiabatic reserve of hot water of a significant volume at the periphery of the digester to manage the flows and refluxes of the heat transfer fluid. Indeed the volume extracted in a drum is transferred into a neighbouring drum, and so on, so as to create a swell wave at tank bottom as described in more detail above. The outer drum is mobilised to inject a volume of heat transfer fluid, which is incremented above the medium volume, only if it is desired to obtain an overflow effect.

[0155] The implementation of this system for non-destructive transfer, brewing and overflow of the digestates also has the advantage of being completed by a system for injection of biogas purified of H.sub.2S, or of CO.sub.2 under a pressure sufficient to ensure micro-oxidation tangentially to the upper surface of the inflatable drums.

[0156] The brewing system according to the invention, a bioreactor equipped with this brewing system, as well as its implementation method, can be associated with additional structural and functional elements. The latter, which should be taken into account for the correct operation of this bioreactor, are not however part of the invention. They will not therefore be described in more detail. These elements are in particular: [0157] solenoid valves, pumps, flowmeters, volume and temperature sensors, drums and additional heat exchangers, [0158] a system for grinding the entering waste and substrates that allows to reduce their relative size into a particle size not exceeding 25 mm. This device can take the form of a dual-axis slow knife mill served by a loading hopper ensuring the protection of the operator, [0159] a preheating and mixing system consisting of a bain-marie or any other equivalent device loaded gravitationally with the organic substrates and the raw compost coming from the mill and receiving the dilution liquid consisting of percolates, [0160] a lift pump accepting highly turbid flows with a maximum particle size of 35 mm intended to supply the bioreactor in the upper part of the latter, [0161] a network of sensors that measure in real or slightly deferred time the values obtained for the temperature, the pH, the turbidity of the digestates during the various phases, the chemical composition, the temperature and the relative humidity of the biogas and of the purified biomethane, [0162] a set of several programmable industrial robots that process the signals received from the sensors, infer the behaviour of effectors and report on the state of the system on a remote control station, [0163] a network of effectors such as hydraulic or pneumatic solenoid valves that regulate the circulation of the flows of substrates, digestates, eluates controlled by the programmable robots or directly by the human operator, [0164] one or more tanks referred to as auxiliary, distinct from the tank 1 described in the drawings, which act as bioreactors to house the various phases of the biodigestion with the means for introducing and evacuating the treated matter, [0165] a system for degassing the digestates at the end of the methane digestion cycle and which can be a simple decantation chamber impermeable to the gas provided or not with specific brewing devices, [0166] a device for filtering the biogas, with the function of separating and treating CO.sub.2 and CH.sub.4 and which can take the form of a cell for solubilisation in water, solvents, reactants, osmotic filters or any other equivalent device, [0167] a device for dehumidification of the biogas having the function of extracting the H.sub.2O water by condensation, and [0168] a device for filtering the biogas having the function of separating and treating the sulphurated hydrogen (H.sub.2S), the siloxanes and nitrogen oxides and which can take the form of a cell for capturing biologically, with activated carbon, or any other equivalent device.