Reactors and methods for biological treatment of wastewater

Abstract

This invention relates to a reactor for biological wastewater treatment, comprising: - a chamber capable of containing a mixture of wastewater and sludge at different liquid levels, each liquid level being defined by sludge concentration and / or density; - an apparatus for determining the minimum and maximum liquid levels for sludge extraction in the chamber, comprising: • a measuring device capable of measuring the sludge concentration and / or density of the wastewater and sludge mixture at different liquid levels; • a selection device capable of selecting a maximum and minimum sludge concentration and / or density value; • a derivation device capable of deriving the minimum extraction liquid level corresponding to the selected maximum concentration value and the maximum extraction liquid level corresponding to the selected minimum concentration value; - an extraction device capable of extracting sludge at a variable liquid level between the minimum and maximum extraction liquid levels.

Description

Technical Field

[0001] This invention belongs to the field of wastewater purification, and more specifically to the field of biological wastewater treatment, namely, treatment using an activated sludge system.

[0002] Based on the following simplified mechanism, the activated sludge method can reproduce the self-healing function of rivers in industry:

[0003] Pollution + Microorganisms + O2 → Microorganisms + H2O + CO2

[0004] Activated sludge is sludge containing microorganisms, and therefore it is most commonly derived from wastewater treatment. It is essentially composed of bacteria. The bacteria are primarily responsible for removing pollutants from wastewater.

[0005] Activated sludge is most commonly found in the form of flocculent particles of various sizes with a wide range of characteristics, and in some applications it is particularly found in the form of sludge granules (also known as biomass particles and biomass pellets).

[0006] In particular, the present invention aims to improve the efficiency of the activated sludge by selecting sludge based on its separation capacity. Existing technology

[0007] Activated sludge systems are designed to remove carbon-based, nitrogen-based, and phosphorus-based pollutants from wastewater.

[0008] carbon-based pollution

[0009] Bacteria present in activated sludge will search for substances necessary to maintain their activity rate in the medium to be treated (typically the effluent to be treated).

[0010] The bacterial culture contained in this sludge includes autotrophic cells, which absorb the energy required from the external medium to convert water, carbon dioxide, and inorganic salts into their own substances and thus form a potential energy reservoir that can be used at any time; and heterotrophic cells, which, in contrast, cannot perform this synthesis and use nutrients (oxidizing them into simpler materials). The energy thus released is directly used for the cells' needs. In this case, it involves degrading nutrients (also called nutrient substrates) and using the energy released thereby.

[0011] To remove carbon from the effluent, heterotrophic cells are used aerobically because oxygen is associated with the degradation reaction. Organic carbon exists in the form of CO2 and biomass.

[0012] Typically, glucose degradation can be schematically illustrated, for example, according to the following equation:

[0013]

[0014] The main nutrient substrates of these bacteria are proteins, carbohydrates, and lipids, but they can adapt to the consumption of other organic substrates (such as alcohols, phenols, aldehydes, hydrocarbons, etc.).

[0015] Bacterial cultures undergo different growth phases and a slow-growth phase. During the lag phase, microorganisms adapt to the nutrient medium: then the growth rate is zero or weakly positive. When the cell reproduction rate reaches its maximum in the presence of an unlimiting concentration of substrate, this is called exponential growth. This will stop as the concentration of the nutrient substrate decreases, which slows the growth rate, causes growth to cease, and may even lead to a regression from the slow phase. A lack of nutrients leads to a decrease in the quality of the microorganisms.

[0016] Therefore, a bacterial culture rich in heterotrophic cells and fully oxidized is required to ensure the removal of carbon-based contaminants. However, bacterial growth requires the presence of other nutrients, particularly nitrogen and phosphorus contained in the effluent, and these elements also need to be removed.

[0017] Nitrogen pollution

[0018] The wastewater also contains various nitrogen-based compounds: proteins, urea, and decomposition products (such as nitrogen in mineral form). The biological removal of these compounds occurs in two steps: nitrification and denitrification, which occur sequentially over time.

[0019] Nitrification involves the conversion of ammonia (NH4+) into nitrogenous substances by autotrophic cells. + 4) Organic nitrogen in the form of nitrogen is oxidized to nitrous acid (NO). - 2), and then oxidized to nitric acid (NO). - 3) According to the following equation:

[0020]

[0021] Autoaerobic bacteria grow at a slower rate than heteroaerobic bacteria. According to the following equation, nitrification can also occur during the aerobic phase of heteroaerobic bacteria:

[0022]

[0023] Denitrification is a process in which heterotrophic cells reduce nitrate nitrogen to a lower oxidized state. It occurs during the anaerobic / anoxic phase according to the following equation:

[0024]

[0025] Phosphorus-based pollution

[0026] Phosphorus removal is also a very important activity, especially since the proliferation of algae on the surface of water bodies significantly restricts the exchange of air and solar energy, thus leading to eutrophication of the water bodies.

[0027] In fact, phosphorus is mainly involved in energy storage or release mechanisms. Studies on the possibility of biological phosphorus removal have shown that unaerated activated sludge releases phosphorus and reabsorbs oxygen once oxygen concentrations recover. The presence of certain bacteria, known as PAO (phosphorus accumulating organisms), is responsible for this phenomenon.

[0028] Biological phosphorus removal utilizes this complex phenomenon and employs PAO bacteria. The idea behind biological phosphorus removal, compared to other organisms, is to provide PAOs with optimal conditions to promote their growth. Therefore, biological phosphorus removal is based on the following observations:

[0029] -PAO is able to store phosphorus in the form of polyphosphate within its cells;

[0030] - Under anaerobic and / or hypoxic conditions, PAO assimilates fermentation products (acetic acid or fatty acids, such as those stored in intracellular macromolecules like polyhydroxybutylene PHB) by using the energy from stored polyphosphates, thus releasing inorganic phosphorus.

[0031] Under aerobic conditions, the stored fermentation products are used to generate energy and for the growth of the bacteria. The energy used is also used to rebuild polyphosphate reserves through the reabsorption of inorganic phosphorus absorbed from the medium. Polyphosphate reserves increase with the growth of PAO bacteria.

[0032] Under aerobic conditions, the reabsorption of inorganic phosphorus is higher than that under aerobic / anaerobic conditions. Therefore, through a series of aerobic / anaerobic and aerobic conditions, it is possible to achieve a gradual accumulation of phosphorus in the form of polyphosphate in these microorganisms, up to a value of up to 10% of its dry weight.

[0033] This entire process results in the removal of approximately 50% to 65% of phosphorus from the wastewater to be treated.

[0034] As shown above, this alternation of anaerobic / anoxic and aerobic conditions / phases is valuable in all other cases of removing carbon-based and nitrogen-based pollution: it makes it possible to regulate the removal of organic carbon required for all steps of the treatment and the proliferation of the microorganisms responsible for its removal; to provide the oxygen required for nitrification while subsequently achieving denitrification in anaerobic and / or anoxic phases; and to enhance phosphorus accumulation in microorganisms during aerobic phases.

[0035] By subjecting biomass to anaerobic and / or anoxic and aerobic conditions, water must be biologically treated in a dedicated reactor, which simultaneously enables phosphorus removal, nitrification, and denitrification.

[0036] Biological treatment of water can be carried out in a continuous reactor. In this case, anaerobic / anoxic and aerobic conditions are achieved through defined anaerobic / anoxic and aerobic zones.

[0037] Biological treatment of water can be carried out alternately in batch or sequential reactors. Sequential biological treatment of water consists of contacting the water to be treated with sludge contained in the reactor, typically through fluidization. This type of reactor is called an SBR, or sequencing batch reactor. In this case, anaerobic / anoxic and aerobic conditions are not carried out through defined anaerobic / anoxic and aerobic zones, but rather through a continuous progression of anaerobic / anoxic and aerobic phases.

[0038] The treated water (i.e., water that has depleted carbon-based, nitrogen-based, and / or phosphorus-based pollution) must then be separated from the sludge for recycling, and sometimes undergoes further treatment (referred to as tertiary treatment).

[0039] Most typically, the separation of treated water and sludge is achieved by settling the sludge at the bottom of the reactor.

[0040] However, sludge exists in water as particles of varying sizes, particularly small particles that set poorly and are typically less than one-tenth of a millimeter in diameter. Therefore, they settle slowly, meaning that biological treatment of the water requires a relatively long time.

[0041] To overcome this drawback, it is preferable to retain only selected sludge particles in the wastewater treatment reactor. The term "granular sludge" is also used. Sludge particles are defined as particles that are tightly aggregated communities of microbial species, typically with a size between 0.1 and 5 mm, and exhibit settling characteristics much faster than conventional activated sludge. Their density is typically between 1.02 and 1.10 kg / L.

[0042] In contrast to the settling rate of approximately 1 m / h for flocculated sludge, the settling rate of the granular sludge under discussion is at least 10 m / h. Therefore, sludge particles that are larger and heavier than other sludge particles have better settling ability.

[0043] In fact, as mentioned in the introduction, sludge is derived from treated wastewater, and the microorganisms that constitute it are derived from complex and uncontrollable phenomena that produce flocculent particles of varying sizes, particularly in filamentous form. Only specific conditions make it possible to obtain granules.

[0044] Therefore, it is necessary to be able to select particles that settle more easily and remove particles that do not settle easily: this is called sludge particle selection.

[0045] The choice can be made either outside the reactor or inside the water treatment reactor.

[0046] In patent WO 2016 / 004082, biological treatment is carried out in a continuous mode, wherein the continuous selection steps of biomass particles (also referred to as granules) occur on the biomass stream leaving the reactor, or by sampling the biomass in the aerobic zone of the reactor. One condition for the effective implementation of this method is the presence of defined anaerobic and / or anoxic zones within the reactor, which contains suitable biodegradable organic material in the form of acetate or fatty acids. Depending on the ratio between the available fatty acids or acetates in the medium and the phosphorus to be extracted, the PAO is able to absorb all phosphorus released in the anaerobic zone and is able to extract other phosphates present in the wastewater, thus making it possible to clearly remove phosphates through the final extraction of phosphate-filled biomass.

[0047] Particle selection systems are located outside the reactor: they can be gravimetric selectors (hydrocyclones, centrifuges, external gravity decanters, etc.) for separating the densest sludge aggregates, or size selectors (screens, filters, membrane devices) for separating the largest sludge aggregates.

[0048] These systems are designed to select the densest and / or largest particles and remove other sludge particles, such as filaments and light flocs, from the process. These methods and systems require large and expensive equipment that is either unusable or difficult to use in actual treatment reactors that bring the water to be treated into contact with sludge particles or flocculation.

[0049] Patents CN 103848497 (DHV) and WO 2004 / 024638 (TU Delft) describe the method, particularly in the name The method described below involves a reaction occurring in an SBR reactor. The actual volume of the sludge particles comprises an external aerobic phase and an internal anaerobic phase. Therefore, patent application WO 2004 / 024638 discloses an SBR (Sequencing Batch Reactor) containing a bed of biomass particles. In the first step, wastewater to be treated is introduced under anaerobic conditions via the bottom of the reactor. The feed flow rate is selected to be relatively slow, thus avoiding the formation of a fluidized bed of biomass particles. After the feed of the wastewater to be treated into the reactor is complete, a non-stirred lag period is observed in the reactor, during which the wastewater to be treated comes into contact with the biomass particles. During this phase, the nutrient substrates present in the water are assimilated by the biomass, and the particles subsequently undergo an increase in their volume and density, particularly promoting the development of PAO (phosphorus accumulating organisms).

[0050] The second step consists of aeration of the reactor via a ramp located in the lower part of the reactor. Nitrogenous pollutants in the water to be treated are then at least partially degraded through nitrification-denitrification. PAO development and phosphate extraction are also permitted. During the third step, the extracted particles are then settled within the reactor before being extracted from the treated water, which has been depleted of nitrogenous pollutants. The technique described herein makes it possible to reduce the concentration of both nitrogenous and phosphorus-based pollutants in water.

[0051] The text mentions a step of selecting particles based on their settling ability, but does not specify how to make the selection.

[0052] Patent application WO 2012 / 175489 from Veolia describes a method similar to the TU Delft patent, employing an SBR reactor. This method further includes an anaerobic step of stirring and forming a fluidized bed of biomass particles. After several cycles, a method for extracting poorly settled particles or fine particles is performed. Extraction is carried out through a stationary system that also collects the treated water and allows extraction from the surface of the treated water. Such a system extracts poorly settled sludge particles by leaching at the top of the reactor. The problem is that the loop for recovering the treated water and the extraction loop share common sections. Therefore, the treated water can contain sludge, particularly small-diameter sludge particles, leading to low-quality treated water and subsequent expensive and lengthy treatment (e.g., filtration, flotation, and possibly clarification treatment with the addition of chemical products such as coagulants and flocculants).

[0053] Degremont's patent application WO 2009 / 050347 describes an SBR reactor configured in two compartments, the first compartment containing a bed of sludge particles and the second compartment containing water to be treated, which is discharged into the first compartment under hydraulic stress (generated by a sequence of depressurization / return to atmospheric pressure). This results in movement on the particle bed, which thus generates pulses and expansions. A concentration zone, including a closed device and located in the second compartment, can be opened during the resuspension of unsettled sludge, making it possible to recover non-agglomerated sludge. This corresponds to the stage that allows water to enter the second compartment. This recovery zone is fixed and located at the bottom of the compartment. In this patent application, the selection and extraction of poorly settling sludge particles is carried out by recovery at the bottom of the reactor compartment, and particularly at its fixed level. This is disadvantageous in that it either extracts sludge particles with good settling ability or does not extract all sludge with poor settling ability, resulting in the extraction of a mixture of various sludge qualities, which requires subsequent selection steps among the sludge particles based on their settling ability. To limit this defect, extensive and long-term treatment / recycling cycles will be required, rather than simply extracting the poor-quality sludge.

[0054] Patent application WO 2007 / 089141 discloses a method for implicitly using an SBR reactor to purify wastewater, wherein wastewater is introduced via the bottom of the reactor to contact sludge particles containing microorganisms, then oxygen-containing gas is injected under these sludge particles, and finally these sludge particles settle. Particles with poor settling ability are extracted from the reactor via a discharge point located at a fixed height in the reactor (e.g., between 50% and 98% of the reactor height).

[0055] The extraction systems mentioned in the above patent applications are difficult to adapt to changes in the operating conditions of the processing system (load, flow rate, solid concentration, temperature). This deficiency is found in all the cited applications. Therefore, it is difficult to control good particle separation in order to obtain particles with the desired settling ability.

[0056] Therefore, the main objective of this invention is to enable the selection and extraction of sludge particles within a water treatment reactor based on their settling ability, and more specifically, to eliminate the aforementioned defects of existing technology systems. Summary of the Invention

[0057] To achieve this effect, the subject of this invention is a reactor for biological treatment of wastewater, comprising:

[0058] - Capable of containing a mixture of wastewater and sludge at different levels, each level defined by sludge concentration and / or density;

[0059] - An apparatus for determining the minimum and maximum liquid levels during sludge extraction in a chamber, comprising:

[0060] • A measuring device capable of measuring the sludge concentration and / or density of a mixture of wastewater and sludge at different liquid levels;

[0061] • A selection device that allows selection of the maximum and / or minimum sludge concentration and / or density values;

[0062] • A derivation device capable of deriving the lowest extraction liquid level corresponding to the selected maximum extraction value and the highest extraction liquid level corresponding to the selected minimum concentration value;

[0063] - An extraction device capable of extracting sludge at a variable level between the lowest and highest extraction levels.

[0064] Therefore, the present invention comprises a reactor for biological treatment of wastewater, the reactor including a selective sludge extraction device.

[0065] The sludge to be extracted is selected using devices for determining the extraction liquid level as a function of the characteristics of the sludge present at these levels. Some of these measuring devices are described below. The selection principle is based on the determination of the lowest and highest liquid levels for sludge extraction, which are determined by measuring the concentration and / or density of the sludge to be extracted. This therefore makes it possible to selectively extract the sludge in a more precise and targeted manner than with existing technology devices, based on the sludge's settling ability, which is related to the sludge's concentration and / or density.

[0066] Extraction is performed using extraction devices, some of which are described below, and this makes it possible to extract sludge between the lowest and highest extraction levels.

[0067] The sludge extraction device has a means of changing the extraction liquid level of the sludge.

[0068] Combining the device for determining the minimum and maximum extraction levels with the extraction device makes it possible to actually perform selective extraction within the reactor. In other words, it eliminates the need for large, expensive equipment, most of which cannot be practically used within the processing reactor and therefore require additional loops and / or chambers.

[0069] Therefore, the device according to the invention makes it possible to extract sludge with weak settling ability more safely and accurately, while retaining sludge with better settling ability.

[0070] Therefore, one advantage of the present invention is that it has an apparatus for extracting sludge with weak settling ability, which makes it possible to extract the sludge within the treatment reactor, the extraction being sufficiently precise to avoid subsequent steps of separating the treated water and sludge outside the reactor, and / or subsequent steps of selecting among different sludge particles outside the reactor.

[0071] Therefore, another advantage of this invention is that it retains only dense sludge particles (or granules) in the reactor. In fact, some of these particles have a better substrate-concentration and electron acceptor gradient between the center (anaerobic) and the edge (aerobic / anoxic) of the particle; this gradient makes it possible for anaerobic centers to grow, allowing more organisms (such as PAO) to be accommodated within them. This thus makes it possible to use the invention for processes such as biological phosphorus removal without requiring selective aerobic, anaerobic, and / or anoxic zones or a sequential aerobic, anaerobic, and / or anoxic time zones.

[0072] Another advantage of the present invention is the improved performance of the treatment and the distribution of tertiary treatment methods (filtration, clarification, etc.), which are sometimes performed after biological water treatment steps and are largely dependent on the sludge settling capacity and the associated settling rate.

[0073] Another advantage is that because sludge particles with weak settling ability are extracted from the reactor, smaller reactors can be designed.

[0074] Finally, another advantage is the ability to extract substances floating in the water (bubbles, fat, floating sludge, foam, etc.), thus preventing their accumulation and inherent problems. For example, the extractor can be positioned such that extraction occurs directly below or on the free level in the reactor.

[0075] According to an advantageous embodiment, the biotreatment reactor further includes a recirculation device capable of recycling the extracted sludge back to the chamber. This makes it possible to improve selectivity by repeating the selective extraction process several times.

[0076] sludge extraction device

[0077] According to one embodiment, the extraction device includes:

[0078] - An extractor, which includes at least a first part having at least one opening on the inner side of the chamber and a second part capable of allowing sludge to exit the chamber;

[0079] - A changing device that can change the position of the extractor's opening, particularly the liquid level of the opening between the lowest and highest extraction liquid levels.

[0080] For all content in this specification, the term "opening" should be understood to mean "at least one opening".

[0081] According to one embodiment, the second part of the extractor further includes a sealed channel at one of the liquid levels in the wall of the chamber to allow sludge to exit the reactor chamber.

[0082] According to one embodiment, the extractor includes a pump, and the changing device includes means for changing the liquid level of the pump in the chamber. The opening of a first portion of the extractor corresponds to the pump inlet, in other words, it is the pump's inlet. A second portion of the extractor is connected to the pump outlet; in other words, the pump's delivery makes it possible to recover sludge from the outside of the chamber.

[0083] Such a system is easy to implement and makes it possible to continuously change the extraction liquid level.

[0084] Alternatively, extraction may include a pump or any other device placed on the outdoor side, and may allow the sludge to leave the reactor chamber.

[0085] Regarding the previous solution, the pump was located outside the chamber. Therefore, the pump did not occupy any space within the chamber. For example, it did not disrupt the reactions occurring within the reactor. This was also advantageous in terms of pump cleaning and maintenance, as the pump did not come into direct contact with the water and sludge being treated.

[0086] According to one embodiment, the extractor includes a tube having a first end with an opening on the indoor side and a second end connected to a second portion of the extractor, and the changing device includes means for moving the tube to either side of its second end in such a way as to change the position of the first end of the tube.

[0087] Such a system is very easy to implement.

[0088] According to one embodiment, the extractor includes a flexible hose having a first end with an opening on the indoor side and a second end connected to a second portion of the extractor, and the changing device includes means for moving the first end of the flexible hose.

[0089] Such a system is easy to implement and highly adaptable because not only is the height of the opening variable, but the distance between the first end and the wall of the chamber can also be modified. For example, it is possible to recover sludge at the liquid level on the wall of the chamber, especially at the liquid level on the wall of the attached extraction device.

[0090] According to one specific embodiment, the device for moving a first end of a flexible hose includes a component connected to the first end of the flexible hose, the component being capable of engaging a screw such that when the screw is actuated, the component is driven to move vertically along the screw.

[0091] This makes it possible to easily, quickly, and, for example, remotely control the first end of the tube.

[0092] The component can be sheet-like or disc-like. For example, it can slide inside the cylinder.

[0093] According to another embodiment, the extractor includes a reservoir connected to a second part of the extractor and has a groove on the interior side, and includes a door having an opening facing the groove, the reservoir and the door being assembled in such a way that fluid cannot circulate between them, and the alteration device includes means for moving the door in a substantially vertical motion.

[0094] In this case, the alteration device therefore includes means for moving the door. The door can be moved easily, quickly, and remotely. For example, this requires vertical translational movement of the door, as well as a considerable vertical displacement on the reactor, or the addition of mechanical means suitable for converting horizontal or rotational movement into said vertical translational movement.

[0095] According to another embodiment, the extractor includes a first cylindrical tube having a generally straight groove on the inner side and a second cylindrical tube having a generally spiral groove on the inner side, one of the cylindrical tubes being placed inside the other and connected to a second portion of the extractor, the first and second tubes being assembled in such a way that fluid cannot circulate between them, the alteration device including means for rotating one of the tubes relative to the other tube.

[0096] These alteration devices make it possible to easily, quickly, and remotely control the opening between the two cylindrical tubes, which corresponds to the intersection between the two slots. This also corresponds to the opening of the first section of the extractor. The alteration device requires rotational movement of one of the tubes and therefore does not require vertical displacement above the reactor. Finally, it makes fine rotation possible, and thus fine alteration of the extract level.

[0097] The assembly of the extraction device described above makes it possible to continuously change the extraction liquid level.

[0098] According to another embodiment, the extractor includes a set of tubes positioned at different liquid levels within a chamber, each tube including a first end having an opening on the inner side of the chamber and a second end connected to a second portion of the extractor, and the changing device includes a set of valves capable of opening or closing the tubes. In this system, it is not necessary to apply movement and / or displacement to all or part of the reactor. Sufficient control is provided over the opening of one or more valves. These extraction devices make it possible to discretely and discontinuously change the extraction liquid level.

[0099] The proposed extraction devices are very diverse, and they can all be easily integrated into existing reactors. An advantage is that they can be selected based on the reactor, its chamber, and / or the environment.

[0100] Device for determining the level of the extract.

[0101] According to one embodiment, the measuring device includes a transmitting device capable of emitting a signal within a mixture of wastewater and sludge, and a receiving device capable of receiving a signal from the emitted signal after traveling a given distance within the wastewater and sludge mixture. The signal transmission / reception technique is non-invasive, easy to implement, allows for near-instantaneous information transfer, and avoids the need for sampling.

[0102] According to one specific embodiment, the signal is a wave, and the transmitting device and / or the receiving device includes a sensor capable of being immersed below the surface of the wastewater and sludge mixture and capable of transmitting and / or receiving waves. A single sensor can serve as both a transmitter and a receiver.

[0103] According to one specific embodiment, the wave is ultrasound. Ultrasonic technology makes it possible to provide accurate and rapid information, making it particularly suitable for this invention. Furthermore, it is not necessary to change the liquid level into which the ultrasonic probe is immersed.

[0104] According to another specific embodiment, the signal is radiation, the transmitting device includes a radiation source, and the receiving device includes a radiation detector configured to receive radiation from the emitted radiation that has traveled a given distance through the wastewater and sludge mixture.

[0105] According to one specific implementation, the biotreatment reactor further includes an immersion riser.

[0106] According to one embodiment, the radiation source (which is a radiation detector) is placed in an immersion riser, and the radiation detector (which is a radiation source) is placed at the liquid level on the outdoor wall.

[0107] In another specific embodiment, the radiation source and the radiation detector are placed at the liquid level on the exterior wall. In this case, backscattering of the signal is used, thus avoiding the need to insert an immersion riser into the chamber. Furthermore, to perform measurements at different liquid levels, it is sufficient to move the single sensor acting as both transmitter and receiver.

[0108] According to a specific implementation scheme, the radiation is gamma radiation.

[0109] According to one embodiment, the measuring device includes a probe and an immersion device capable of immersing the probe at different liquid levels in a mixture of wastewater and sludge to measure the concentration of sludge at these different liquid levels. This makes it possible to measure the concentration at different liquid levels and thus correlate the concentration with the liquid level.

[0110] According to one specific implementation scheme, the probe for measuring sludge concentration includes an optical absorber.

[0111] The subject of this invention is also a method for biologically treating wastewater in a reactor according to the invention, comprising the following steps:

[0112] - Determine the minimum and maximum extraction levels of sludge in the chamber;

[0113] - Extract sludge between the lowest and highest extraction levels.

[0114] According to a preferred embodiment, the method includes a sludge settling step.

[0115] According to one embodiment, the method includes the step of introducing wastewater into a chamber.

[0116] According to one embodiment, the method includes the step of treating wastewater by reactive biological treatment with activated sludge.

[0117] According to one embodiment, the method further includes the step of extracting treated water at a level above the highest sludge extraction level.

[0118] According to one implementation, the step of extracting treated water occurs after the step of introducing wastewater into the chamber and after the sludge settling step. This model is suitable for variable level reactors.

[0119] According to one implementation, the step of introducing wastewater into the chamber is performed simultaneously with and after the sludge settling step, followed by the extraction of treated water. This model is suitable for stationary level reactors.

[0120] According to one embodiment, the method includes the step of recycling the extracted sludge back to the bioreactor. This makes it possible to improve the precision of selection by repeating the selective extraction process several times.

[0121] According to one specific implementation, the reactor is a sequential reactor, and all steps are repeated at least once. This also makes it possible to improve the accuracy of selection. Attached Figure Description

[0122] The invention will now be understood more clearly, and other advantages will emerge from reading the detailed description of several embodiments given by way of example, illustrated in the accompanying drawings, wherein:

[0123] - Figure 1 An example of a reactor according to the present invention is shown;

[0124] - Figures 2A to 2G Several reactors according to several embodiments of the present invention are shown, including ultrasonic probes and different extraction devices;

[0125] - Figure 3A and 3B Two reactors are shown according to two different embodiments, including a system comprising a gamma radiation source and a gamma radiation detector placement;

[0126] - Figures 4A to 4F A method for use in a variable-bed SBR reactor according to one embodiment of the present invention is shown;

[0127] - Figures 5A to 5F Another embodiment of the invention is shown, applied to a fixed-bed SBR reactor;

[0128] - Figures 6A to 6F A method applied to a continuous reactor according to an embodiment of the present invention is shown;

[0129] - Figure 7 The graph shows the sludge height as a function of sludge concentration and settling time, with the concentration before settling being 4 g / L.

[0130] - Figure 8A and 8B This graph shows the sludge concentration or suspended solids (MES) concentration obtained on the sludge bed after 110 minutes of settling for two different reactors, R1 (Jougne) and R2 (Pithiviers). Detailed Implementation

[0131] Figure 1 An example of a reactor 1 according to the invention is shown. The reactor 1 includes a chamber 3. The chamber 3 includes one or more vertical walls 3a, a bottom wall 3b, an opening 3c at the top, and optionally a rim 3d.

[0132] During wastewater treatment, chamber 3 is filled with a mixture of wastewater and sludge 2. Once the sludge has settled, water is present in the upper part of the reactor chamber. Water can be drawn through the chamber opening 3c by a device capable of extracting water and including a floating section 4a, such that the extraction system follows the free surface of the water, and an immersed pipe 4b connected to the floating section through which water can be drawn and extracted from the chamber (arrow A).

[0133] The heaviest and / or densest sludge particles are at the bottom, and they can be removed at the liquid level on the bottom wall 3b of the chamber. In between, there is a residual mixture in a stratified form, that is, it has several liquid levels N1, N2, N3, N4, N5, N6, etc., each liquid level being defined by the sludge concentration and / or density in mixture 2.

[0134] The reactor 1 according to the invention makes it possible to selectively extract sludge that is least likely to settle in the mixture 2. For this purpose, the reactor includes means 10 for determining the minimum and maximum liquid levels of sludge extraction in a chamber including a measuring device 11 (e.g., a measuring probe). The measuring probe makes it possible to measure the sludge concentration and / or density in the mixture. As illustrated, the measuring probe 11 may be immersed in the mixture or not. Depending on the type of probe selected, it may be at a fixed or variable immersion depth.

[0135] The measuring probe 11 is connected to a selection device 12 and a derivation device 13. The selection device 12 makes it possible to verify whether the measurement corresponds to the sludge to be extracted, and the derivation device 13 makes it possible to correlate the measurement with the corresponding liquid level. These measuring devices 10 are connected to the sludge extraction device 20, and more specifically to a changing device 22 for selecting the extraction liquid level. The changing device 22 changes the liquid level at the opening 21a of the extractor 21.

[0136] The reactor 1 according to the invention therefore includes a device 20 for extracting sludge, the extraction liquid level of which can be varied.

[0137] The extracted sludge can be discharged (arrow B) or recycled back into reactor 1 (arrow C).

[0138] The reactor 1 may include a device 30 for recycling the extracted sludge into the chamber 3.

[0139] The extraction device 20 may include a device 23 that makes it possible to transport the extracted sludge for discharge or to recycle it into the reactor 1.

[0140] Figures 2A to 2G Several reactors 1 according to several embodiments of the present invention are shown, said reactor 1 comprising an ultrasonic probe and various extraction devices.

[0141] In all the following figures, the extractor 21 is partially introduced into chamber 3 and partially immersed in the wastewater and sludge mixture 2.

[0142] exist Figures 2A to 2G In an embodiment (not fully shown for 2F), the extractor 21 includes a second portion 21b, which in this case is combined with an outlet circuit 21b that allows sludge to exit chamber 3.

[0143] The outlet circuit 21b may include at least one fixed pipe that passes through the wall of the chamber 3 in a sealed manner.

[0144] It can be any other device used to pass through the wall. The wall can be a vertical wall or a bottom wall.

[0145] More broadly, the outlet circuit 21b may include hoses and / or pipes or any device capable of allowing sludge to exit chamber 3. These may be devices that do not require passage through the vertical or bottom wall of the chamber, for example, using the opening 3c of the chamber.

[0146] Additionally, the extraction device 20 may include a three-way system 23, which includes a pipe 23a equipped with two valves 23b and 23c (or a three-way valve) to guide the extracted sludge out of the reactor B, or to recycle the sludge C into the reactor. The three-way system 23 is connected to an outlet circuit 21b.

[0147] Additionally, the outlet circuit 21b may include a valve 21c. For example, the valve may enable control over the opening or closing of the outlet circuit 21b and the three-way system 23.

[0148] exist Figure 2A In the embodiment shown, the extractor 21 includes a pump 210 that is introduced into the chamber 3 and immersed in the mixture 2, and the changing device 22 is capable of changing the liquid level of the pump 210 in the chamber. For example, it may be a winch 220, making it possible to control the winding and unwinding of cables, chains, or any other type of wire 221 connected to the pump.

[0149] The sludge extraction level corresponds to the level of the pump in the chamber, and more specifically to the level of the pump's inlet 210a. The pump outlet 210b (delivery port) is connected to the outlet circuit 21b in such a way that it causes the pumped sludge to leave the chamber 3.

[0150] according to Figure 2A The outlet circuit 21b includes a flexible hose portion and a fixed tube portion that pass through the wall of chamber 3.

[0151] exist Figures 2B to 2G In the illustrated embodiment, the extraction device 20 may include a pump or any other device for removing sludge from chamber 3.

[0152] exist Figure 2B In the illustrated embodiment, the extractor 21 includes a tube 211 having a first end 211a with an opening in the chamber 3, and a second end 211b connected to the outlet circuit 21b. The tube 211 is rigid and movable about its second end 211b, which forms a hinge. A control device 22 includes, for example, a winch 220, which makes it possible to control the winding and unwinding of a cable, chain, or any other type of wire 221 connected to the first end 211a of the tube. In this way, the liquid level at the first end 211a, and therefore the liquid level at the opening of the tube, and ultimately the sludge extraction liquid level, changes.

[0153] exist Figure 2C The illustrated implementation scheme is the same as Figure 2BThe difference in the embodiment shown is that the tube 211 can have a variable length, for example, it can be telescopic, and the control device 22 can include a motor 222 that rotates and is capable of rotating the tube 211 about its second end 211b. In this way, the liquid level at the first end 211a, and therefore the liquid level at the opening of the tube, and ultimately the sludge extraction liquid level, changes.

[0154] exist Figure 2D In the illustrated embodiment, the extractor 21 includes a flexible hose 212 with a first end 212a having an opening in the chamber 3 and a second end 212b connected to the outlet circuit 21b. The first end 212a is connected to an assembly 223 that engages with a screw 224 (e.g., a worm screw). Thus, when the screw 224 is actuated, the assembly 223 is driven to move vertically along the screw. In this way, the liquid level at the first end 212a, and therefore the liquid level at the opening of the hose, and ultimately the sludge extraction liquid level, changes.

[0155] The component 223 can be plate-shaped or disc-shaped. In the example shown, it slides inside the cylinder 225. The screw 224 can be manually actuated or actuated by a device such as a rotating (not shown) electric motor.

[0156] exist Figure 2E In the illustrated embodiment, the extractor 21 includes a reservoir 213 connected to an outlet circuit 21b, wherein the walls have grooves 213a and include a door 214 having an opening 214a facing the straight grooves 213a. The door 214 slides in a sealing manner along the inner wall of the reservoir having the grooves (or alternatively along the outer wall); this is because there is no sludge and no liquid must circulate between the door 214 and the inner wall of the reservoir 213. The changing device 22 includes a motor 226 operating in a translational mode and connected to the door 214 to cause the door to move substantially vertically. In this way, the liquid level at the opening 214a of the door opposite the grooves 213a of the reservoir changes, and thus the sludge extraction liquid level in the reservoir 213 changes, and then the liquid level outside the chamber 3 changes via the outlet circuit 21a.

[0157] exist Figure 2FIn the illustrated embodiment, the extractor 21 comprises a first cylindrical tube 215 having a straight groove 215a and a second cylindrical tube 216 having a generally spiral groove 216a, one of which is positioned inside the other, and the first and second tubes are assembled in such a manner that fluid cannot circulate between the two tubes. The inner tube is connected to the outlet circuit 21b. The changing device 22 includes an electric motor 227 capable of causing one of the tubes to rotate relative to the other. Sludge passage occurs at the liquid level at the intersection of the straight groove 215a and the spiral groove 216a. In this way, the liquid level at the opening 21a corresponding to the intersection changes, and thus the sludge extraction liquid level in the inner tube changes, and then the liquid level outside the chamber 3 changes via the outlet circuit 21b.

[0158] exist Figure 2G In the illustrated configuration, the extraction device includes a set of tubes 217 positioned at different liquid levels within a chamber 3 and passing through at least one vertical wall of the chamber. Each tube has a first end 217a open in the chamber 3, and a second end 217b connected to a collector 21d. The collector 21d is connected to the outlet circuit 21b. The control device 22 includes a set of valves 228 capable of opening or closing the tubes.

[0159] In this figure, the collector 21d and the valve 228 are located outside the chamber, which requires several channels to enter the chamber.

[0160] Advantageously, the collector 21d can be placed in the chamber 3, which avoids having multiple channels into the chamber (with the associated risk of leakage).

[0161] One or more valves 228 can be placed in chamber 3.

[0162] Alternatively, the connection between the tube 217 and the collector 21d can pass through the upper opening of the chamber 3, without having to pass through the vertical or bottom wall of the chamber.

[0163] exist Figures 2B to 2G In the embodiments shown, it is sometimes necessary to provide a pump or any other device to extract or suck sludge from the reactor.

[0164] exist Figures 2A to 2GIn the embodiment shown, the measuring device 11 of the measuring apparatus 10 includes an ultrasonic sensor immersed below the surface of the wastewater and sludge mixture. The ultrasonic sensor makes it possible to send ultrasonic waves into the mixture (and then operate as a transmitter), and then receive the returned ultrasonic waves after the ultrasonic waves have traveled a given distance in the wastewater and sludge mixture (and then operate as a receiver). The sensor is connected to the selection device 12 and the derivation device 13.

[0165] Figure 3A and 3B A reactor according to another embodiment of the invention is shown, including another measuring device 11. Furthermore, an extraction device 20, which may be one of the previously shown devices, is shown schematically, and a recycling device 30 is also presented.

[0166] exist Figure 3A and 3B In the embodiment shown, the measuring device 11 capable of measuring sludge concentration and / or density includes a system comprising a gamma radiation source 110 and a gamma radiation detector 111, otherwise referred to as a gamma measurement system. The gamma radiation detector 111 is configured to receive gamma radiation 113 that has traveled a given distance from the emitted gamma radiation 112 within the wastewater and sludge mixture 2.

[0167] exist Figure 3A In the illustrated embodiment, the reactor 1 includes a partially introduced chamber 3 and, in the illustrated example, an immersion riser 5 immersed in the mixture 2. A radiation source 110 is placed in the immersion riser. A radiation detector 111 is placed close to the outer wall (e.g., a vertical wall) of the chamber 3. The detector 111 is connected to the selection device 12 and the guiding device 13.

[0168] exist Figure 3B In the embodiment shown, the radiation source 110 and the radiation detector 111 are placed close to the outer wall (e.g., a vertical wall) of the chamber 3. In this case, the system operates by backscattering. The detector 111 is connected to the selection device 12 and the derivation device 13.

[0169] Alternatively, instead of an ultrasonic probe or gamma measurement system, an optical probe can be installed to measure turbidity at different liquid levels.

[0170] All the implementation schemes described above can be combined with each other.

[0171] The reactor described in relation to the previous figures can be an SBR batch reactor, a continuous reactor, or any other effluent treatment reactor.

[0172] Methods for biological treatment of wastewater typically include all or some of the following stages, and will be referred to as:

[0173] - Filling stage: Wastewater is allowed to enter the reactor;

[0174] - Reaction phase: biological removal of pollutants (organic matter, nitrogen, and phosphorus); including an aeration phase and optionally anaerobic and anoxic phases;

[0175] - Settling stage: Separating sludge and treated water through sludge settling;

[0176] - Extraction stage: Extract the treated water.

[0177] The selective extraction process preferably includes a settling stage, in which sludge in the reservoir can settle. Depending on the reactor type (continuous, SBR, pulsed or non-pulsated, mixed or unmixed, etc.), this corresponds to the interruption or reduction of hydraulic and / or mechanical agitation of the wastewater and sludge mixture, and the interruption or reduction of the injection of fluidizing gas and / or aeration gas, etc. Particles with strong settling ability reach the lower layer of the sludge, while particles with weak settling ability remain in the upper layer.

[0178] After a sufficient period of time for settling to occur (e.g., between 0.1 and 4 hours), the minimum and maximum extraction levels are determined. The extractor extracts sludge at a first extraction level between the minimum and maximum extraction levels, continuing for a period of time to extract the desired amount of sludge. The extractor then withdraws sludge at a second extraction level between the minimum and maximum extraction levels.

[0179] The extraction liquid level was adjusted and the subsequent sludge extraction operation was performed several times.

[0180] Advantageously, to improve selectivity, the extracted sludge stream can be recycled back into the chamber. In practice, in this case, selectivity is improved by repeating the selective extraction process several times.

[0181] Through examples Figures 4A to 4F 5A to 5F and 6A to 6F present three types of method cycles that can be applied to different reactor types.

[0182] The method according to the present invention applied to a variable level SBR reactor is shown in Figures 4A to 4F middle.

[0183] The reactor shown comprises two compartments: an anaerobic / anoxic first compartment (referred to as the selector compartment), through which wastewater and sludge are injected together, the sludge originating from a recycle in the second compartment (referred to as the main zone).

[0184] The water treatment cycle consists of the following: each stage lasting approximately 30 minutes, including filling and reaction, reaction, settling, and extraction. The treated water is then pumped through extraction system 4 to the upper liquid level of the reactor. Figure 4D Arrow A) Discharge. The maximum height of the liquid in the reactor is approximately six meters, and there is a variable-level extractor 21.

[0185] At the end of or during the settling phase, selective extraction is performed at several variable levels between lower and higher extraction levels. The extraction levels are variable. During the first extraction phase (e.g., lasting fifteen minutes), the extracted sludge is recycled back into the chamber. Figure 4D Arrow C), or discharge ( Figure 4E Arrow B) is used to facilitate the removal of weakly settling particles.

[0186] The method according to the present invention applied to a fixed-level SBR reactor is shown in Figures 5A to 5F .

[0187] To maintain a constant liquid level, the filling and extraction phases occur simultaneously. Wastewater is introduced via the bottom of the chamber (under anoxic or anaerobic conditions). The treated water is then extracted through the extraction system 4 to the upper liquid level of the reactor. Figure 5A Arrow A) is discharged.

[0188] The next stage is the reaction stage, in which aeration and / or mixing occur in the reactor, making it possible to treat the wastewater.

[0189] Using extraction device 20, selective extraction is performed at several variable levels between lower and higher extraction levels, during the final portion of the settling period and / or during the subsequent filling and extraction phases. During the first extraction portion (e.g., fifteen minutes), the extracted sludge is either extracted or recycled into the chamber. Figure 5E Arrow C), or discharge ( Figure 5F Arrow B) is used to facilitate the removal of weakly settling particles.

[0190] In the two SBR methods presented, there is a stepwise selection of fast-settling particles through several repeated loops.

[0191] The method of the present invention applied to a conventional continuous flow reactor is shown in Figures 6A to 6F (e.g., conventional activated sludge (CAS), integrated immobilized membrane activated sludge (IFAS), or membrane bioreactor (MBR)). In these cases, there is no stage where sludge can freely and statically settle, nor is there a compartment where said free and static settling occurs. Through the extraction system 4, there is a continuous inflow of wastewater or a mixture of water and sludge (arrow D) and an outflow of treated water (arrow A). The aeration tank can be aerated intermittently, aerated only, or mixed only.

[0192] In the method according to the invention, mixing and / or aeration of the aeration tank is interrupted for one to two hours, allowing the sludge to settle at the bottom of the tank after a period of time (sedimentation phase) that varies, for example, between 0.1 and 4 hours.

[0193] Using extraction device 20, selective extraction is performed at several variable liquid levels between lower and higher extraction levels to facilitate the selective discharge of particles with weaker sedimentation. Figure 6E Arrow C indicates the recirculation of sludge into the reactor, and Figure 6F Arrow B indicates the discharge of sludge. The extraction height can be adjusted during the extraction stage.

[0194] In all the presented embodiments, the extraction device 20 also makes it possible to extract floating reactor material (foam, fat, floating sludge, foam, etc.) from the water to prevent its accumulation and inherent problems, which occur not only during the settling phase but also during other phases. The extraction device can be arranged such that the extraction occurs directly below or above the free level in the reactor.

[0195] In addition, one or more steps of conventional sludge extraction at the bottom of the reactor and / or sludge recycling can be carried out in parallel with the method according to the invention.

[0196] The methods described above will all work better and / or be more advantageous if the organisms can develop slowly in the sludge to achieve a dense structure (e.g., phosphorus-accumulating organisms (PAO), denitrifying bacteria, or methanogenic bacteria), as mentioned in the introduction of this paper.

[0197] In addition, an anaerobic ammonia oxidation process is carried out to process NH4+. + Anaerobic bacteria that oxidize ammonium can develop in dense granular environments, and the coexistence of ammonia and nitrite in the absence of oxygen promotes their growth. These bacteria have the advantage of enabling relatively inexpensive oxidation of ammonia and also carrying out denitrification, which consumes less organic matter.

[0198] Figure 7 A graph showing sludge height as a function of sludge concentration for a given reactor, with a concentration of 4 g / L before settling, is displayed, and extraction is carried out at higher concentrations (e.g., 5–7 g / L).

[0199] For this type of reactor, the optimal settling time for sludge extraction appears to be 130 minutes. Concentration levels can be established, and effective selective extraction may be possible. It is possible to refine concentration measurements to facilitate more precise extraction.

[0200] Figure 8A and 8B This graph shows the sludge concentration or suspended solids (MES) concentration obtained on the sludge bed (LB) after 110 minutes of settling for two different reactors, R1 (Jougne) and R2 (Pithiviers).

[0201] In both cases, by extrapolating the concentration as a function of bed height, concentration measurement makes it possible to obtain a linear model. For a given reactor, this model can be used in the measuring device 10, and particularly in the selection device 12.

[0202] The reactor and method according to the invention can be advantageously applied when denser particles are added to or generated in the sludge.

[0203] For example, activated carbon in the form of dense particles can be added to sludge. In practice, activated carbon particles can be used to adsorb trace pollutants, particularly drug residues in wastewater. By allowing selective extraction and retention of the densest sludge, the reactors and methods according to the invention facilitate the retention of activated carbon in the reactor for a longer period.

[0204] The device used to determine the extraction level can be adapted to more precisely target activated carbon particles: the minimum extraction level must be just above the level of the sludge containing activated carbon particles so that the activated carbon is not extracted along with particles that have weak settling ability. Due to the extended residence time of the activated carbon, the adsorption capacity may be higher and / or the amount of activated carbon to be added to the sludge can be reduced.

[0205] Another example of an advantageous application of the invention relates to the acquisition of struvite (NH4MgPO4) precipitate. Struvite deposition in water treatment reactors can lead to extremely low development efficiency due to blockages in hoses, pumps, and other equipment; however, struvite is another device for utilizing sludge as a slowly assimilated agricultural fertilizer. Preferably, the struvite is retained at the bottom of the reactor and recovered from the bottom during or after wastewater treatment. The struvite can form in wastewater containing ammonium, magnesium, and phosphate in compatible molar proportions. The reactor and method according to the invention promote this retention of struvite precipitate in the reactor, making it possible to recover the precipitate during subsequent extraction and / or treatment steps (e.g., separation from remaining dense sludge).

[0206] Struvite precipitates can also originate from anaerobic digester effluent, which is transferred to the reactor according to the invention. Aeration and / or mechanical or hydraulic stirring are interrupted after the reaction stage. A sedimentation stage allows precipitate to settle. Selective extraction makes it possible to retain struvite precipitates in the reactor, preferably at the bottom, so that they can be pumped out and transferred to a dewatering unit for fertilizer production. The device used to determine the extraction level can be modified for more precise targeting of struvite precipitates: the minimum extraction level will be just above the level of the sludge containing struvite, so as not to be extracted along with particles with weak settling ability.

Claims

1. A reactor (1) for biological wastewater treatment, comprising: selecting and extracting sludge particles based on their settling ability, including: - A chamber (3) capable of containing a mixture of wastewater and sludge (2), wherein water is in the upper part of the reactor chamber when the sludge has settled, the heaviest and / or densest sludge particles are in the bottom of the reactor chamber, and there is a residual mixture in a stratified form between the water and the heaviest and / or densest sludge particles, having several liquid levels, each liquid level being defined by sludge concentration and / or density; - An apparatus (10) for determining the minimum and maximum liquid levels of sludge extraction in the residual mixture, comprising: • A measuring device (11) capable of measuring the sludge concentration and / or density of a mixture of wastewater and sludge at different liquid levels; • A selection device (12) that allows selection of the maximum sludge concentration and / or density value and the minimum sludge concentration and / or density value; • A derivation device (13) is capable of deriving the lowest extraction liquid level corresponding to the selected maximum sludge concentration value and the highest extraction liquid level corresponding to the selected minimum sludge concentration value based on the measurement results of the measuring device (11), wherein the measuring device is connected to the selection device and the derivation device. - An extraction device (20) capable of extracting sludge at a variable level between the lowest and highest extraction levels from the remaining mixture, wherein the measuring device, the selection device and the derivation device are connected to the extraction device.

2. The reactor (1) of claim 1, further comprising a recirculation device (30) capable of recirculating the extracted sludge back into the chamber.

3. The reactor (1) according to any one of claims 1 and 2, wherein the extraction device (20) comprises: - Extractor (21), which includes at least a first part having at least one opening (21a) on the inner side of the chamber (3) and a second part (21b) capable of allowing sludge to leave the chamber; - A changing device (22) that can change the position of the opening (21a) of the extractor (21).

4. The reactor (1) of claim 3, wherein the changing device (22) is capable of changing the position of the opening of the extractor (21) between the lowest extraction liquid level and the highest extraction liquid level.

5. The reactor of claim 3, wherein the extractor (21) includes a pump (210), and the changing device (22) includes means for changing the liquid level of the pump in the chamber.

6. The reactor of claim 3, wherein the extractor (21) comprises a tube (211) having a first end (211a) having an opening in the chamber (3) and a second end (211b) connected to the second portion (21b) of the extractor (21), and the changing device (22) comprises means for moving the tube to either side of its second end (211b) in such a way as to change the position of the first end of the tube.

7. The reactor of claim 3, wherein the extractor (21) comprises a flexible hose (212) having a first end (212a) having an opening inside the chamber (3) and a second end (212b) connected to a second end of the extractor (21), and the changing device (22) comprises means for moving the first end of the flexible hose.

8. The reactor of claim 7, wherein the device for moving a first end (212a) of a flexible hose (212) includes a component (223) connected to the first end of the flexible hose, the component being capable of engaging a screw (224) such that when the screw (224) is actuated, the component (223) is driven to move perpendicularly along the screw.

9. The reactor of claim 3, wherein the extractor (21) comprises a reservoir (213) connected to the second portion (21b) of the extractor (21) and having a groove (213a) on the inner side, and includes a door (214) having an opening (214a) facing the groove (213a), the reservoir (213) and the door (214) being assembled in such a manner that fluid cannot circulate between them, and the alteration device (22) includes means for moving the door in substantially vertical motion.

10. The reactor of claim 3, wherein the extractor (21) comprises a first cylindrical tube (215) having a substantially straight groove (215a) on the inner side; and a second cylindrical tube (216) having a substantially spiral groove (216a) on the inner side, one of the cylindrical tubes being placed inside the other and connected to the second portion (21b) of the extractor (21), the first and second cylindrical tubes being assembled in such a manner that fluid cannot circulate between them, and the changing device (22) comprising means for rotating one of the cylindrical tubes relative to the other cylindrical tube.

11. The reactor of claim 3, wherein the extractor (21) comprises a set of tubes (217) placed at different liquid levels in the chamber, each tube (217) having a first end (217a) and a second end (217b), the first end (217a) having an opening inside the chamber (3); the second end (217b) being connected to the second portion (21b) of the extractor (21), and the changing device (22) comprising a set of valves (228) capable of opening or closing the tubes.

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