System and method for determining at least one operating parameter of a biological treatment plant for the production of biogas with recovery of nitrogenous nutrients

Abstract

The invention describes the coupling of an anaerobic biological system (110) with a bioelectrochemical system (120) to intensify the operation of the anaerobic system and recover the ammoniacal nitrogen contained in a digestate (3). The invention determines at least one operating parameter of an evaporation extraction system removing volatile organic matter from a liquid medium as a function of a value of a ratio characteristic of the mixture of this volatile organic matter with the digestate (3), this ratio being representative of a quantity of biodegradable organic matter relative to a quantity of ammonium ions.The value of this ratio is determined as a function of (bi) a target yield of ammonium ions extracted from the bioelectrochemical treatment system or a target concentration of ammonium ions separated by this system, and (bii) the value of at least one parameter representative of the capacity of the electrochemical treatment system to separate ammonium ions and at least one digestate quality parameter. Abstract figure: Figure 1.

Description

Title of the invention: System and method for determining at least one operating parameter of a biological treatment plant for the production of biogas with recovery of nitrogenous nutrients Field of invention

[0001] The present invention relates to the field of effluent treatment by an anaerobic biological system producing biogas and digestate, and in particular the coupling of such an anaerobic biological system with a bioelectrochemical system allowing the intensification of the operation of the anaerobic biological system and the recovery of the ammoniacal nitrogen contained in the digestate produced. State of the art

[0002] Anaerobic biological treatment corresponds to a cascade of biochemical reactions allowing the conversion of organic matter present in an anaerobic biological system into biogas, mainly a mixture of carbon dioxide and methane. The remaining materials are called digestate.

[0003] Most anaerobic biological processes have as their main objective the production of energy in the form of biogas. However, the recovery of nutrients from digestates is increasingly being studied due to the increase in the price of inorganic fertilizers, particularly nitrogen fertilizers, and the scarcity of resources, particularly phosphorus.

[0004] Thus, many methods for recovering nutrients from digestate have been developed in recent years. One method consists of treating the digestate by an electrochemical process which allows the ammoniacal nitrogen contained in the digestate to be recovered by electrodialysis or by migration from an anode compartment to a cathode compartment. The concentrated ammoniacal nitrogen stream thus recovered can then be separated and concentrated by stripping and absorption. This method has the advantage of limiting the quantity of chemical reagents necessary for its implementation but requires significant electrical energy consumption due to the significant potential difference which must be applied to the system for the implementation of the electrochemical process.

[0005] It is possible to reduce energy consumption significantly by replacing the electrochemical process with a bioelectrochemical process in which at least one of the redox reactions is catalyzed by electroactive microorganisms. However, the implementation of this type of process is difficult to control because the needs of the electroactive microorganisms for biodegradable material are in competition with biogas production from the digestion stage.

[0006] There is therefore a need to achieve a coupling of an anaerobic biological system producing biogas and digestate with a bioelectrochemical digestate treatment system which makes it possible both to produce biogas and to optimize the recovery of nitrogenous nutrients contained in the digestate at lower cost. Summary of the invention

[0007] To this end, a method is proposed for determining at least one operating parameter of a biological treatment plant for an input containing carbonaceous material and nitrogen compounds, the plant comprising: - an anaerobic biological system producing biogas, notably methane, and digestate, and - an extraction-evaporation system adapted to extract a portion of a liquid medium containing biodegradable organic matter and to separate it by evaporation into a volatile fraction containing volatile organic matter and a concentrated fraction returned to the liquid medium, - a bioelectrochemical treatment system receiving the digestate or a liquid fraction thereof and said volatile fraction, this bioelectrochemical treatment system comprising electroactive microorganisms and at least one separator capable of allowing ammonium ions to pass when a potential difference is applied.

[0008] According to the invention, the determination method comprises: (a) a step of acquiring (ai) a value of at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions, and (aii) a value of at least one quality parameter of the digestate or its liquid fraction, representative of a quantity of ammonium ions relative to a total quantity of cations, (b) a step of determining a value of a ratio characteristic of the mixture of said volatile fraction with the digestate or its liquid fraction, representative of a quantity of biodegradable organic matter relative to a quantity of ammonium ions, this value being determined as a function of (bi) a target yield of ammonium ions extracted from the bioelectrochemical treatment system or a target concentration of separated ammonium ions present in the bioelectrochemical treatment system, and (bii) the values acquired in step (a), (c) a step of determining at least one operating parameter of the extraction-evaporation system as a function of the value of the ratio determined in step (b), the at least one operating parameter of the extraction-evaporation system being chosen from the evaporation temperature, the evaporation pressure, the frequency of extraction of the portion from the liquid medium, the flow rate of the portion extracted from the liquid medium.

[0009] The at least one operating parameter of the extraction-evaporation system determined by the method according to the invention makes it possible to extract the quantity of volatile biodegradable organic matter just necessary for the operation of the bioelectrochemical treatment system, optionally taking into account the presence of biodegradable organic matter present in the digestate. This makes it possible not to modify the operating conditions of the anaerobic biological system, which can then be operated in such a way as to maximize the production of biogas. Indeed, even under conditions of optimization of the production of biogas, there is formation of a certain quantity of biodegradable organic matter within the anaerobic biological system, in particular due to the presence of ammonium ions.

[0010] Ammonium ions are in fact known to cause an inhibitory effect on anaerobic digestion by partially blocking the biochemical reactions of methanization and thus leading to a certain accumulation of biodegradable organic matter.

[0011] This biodegradable organic matter typically comprises organic compounds capable of being oxidized by electroactive microorganisms, namely essentially volatile fatty acids (VFAs), and / or alcohols (methanol, ethanol, etc.), or even other organic molecules of the micropollutant type. VFAs are fatty acids whose carbon chain contains at most 6 carbon atoms. These are mainly acetic acid or acetate, propionic acid or propionate and butyric acid or butyrate, but also isobutyric acid or isobutyrate (iC4 or isoC4), valeric acid or valerate (C5), isovaleric acid or isovalerate (iC5 or isoC5), 2-methyl butyrate (2-mb), caproic acid or caproate (C6).

[0012] During optimal operation of an anaerobic biological system, aimed at maximizing the production of biogas, a large majority of this biodegradable organic matter is thus degraded by the biochemical reactions involved to produce methane. However, the remaining quantity can accumulate and degrade the operation of the digestion system. Thus, the extraction-evaporation of these compounds, at least in part, by an extraction-evaporation system, makes it possible to extract these inhibitory compounds from the anaerobic biological system, thus improving its operation and making it possible to provide the bioelectrochemical treatment step with the biodegradable matter necessary for its proper operation and the recovery of ammonium ions.

[0013] In one embodiment, the anaerobic biological system may be a two-phase anaerobic digestion system, the liquid medium then being the contents of a fermenter, in particular a hydrolysis and acidogenesis reactor, located upstream of a digester, in particular an anaerobic digester, producing the biogas and the digestate. The installation may then comprise a two-phase anaerobic digestion system comprising a fermenter implementing a first phase, advantageously a hydrolysis and acidogenesis phase, and a digester implementing a second phase, advantageously an acetogenesis and methanogenesis phase, and producing biogas, in particular methane, and a digestate. The extraction-evaporation system is then adapted to extract a portion of the contents of the fermenter and to separate it by evaporation into a volatile fraction containing volatile organic matter and a concentrated fraction returned to the fermenter.

[0014] The acquisition step (a) may comprise one or more of the following characteristics: - the at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions is chosen from at least one parameter representative of the capacity of the at least one separator to allow the ammonium ions to pass, and a parameter representative of a concentration gradient of the cations on either side of the at least one separator, - the at least one parameter representative of the capacity of the electrochemical treatment system to separate ammonium ions is at least one parameter representative of the capacity of the at least one separator to allow ammonium ions to pass, and its value is estimated or determined from intrinsic characteristics of the separator, - the at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions is at least one parameter representative of a concentration gradient of the cations on either side of the at least one separator, and its value is estimated or calculated, - at least one quality parameter of the digestate or its liquid fraction is chosen from the ratio of its ammonium ion concentration to its conductivity or the ratio of its ammonium ion concentration to its total cation concentration, - the value of at least one quality parameter of the digestate or its liquid fraction is estimated or calculated based on the concentration of the digestate or its liquid fraction in ammonium ions, and its conductivity or its total concentration in cations.

[0015] The invention also provides a method for the biological treatment of an input containing carbonaceous material and nitrogen compounds to produce biogas and recover ammonium ions, by means of a biological treatment installation as previously described, the method comprising: - a step of determining at least one operating parameter of the extraction-evaporation system implementing the determination method according to the invention, - an anaerobic biological treatment stage producing biogas and digestate, in particular under conditions for maximizing biogas production, - an extraction-evaporation step during which a portion of the contents of a liquid medium containing biodegradable organic matter is extracted and then subjected to evaporation to separate a volatile fraction and a concentrated fraction, and the concentrated fraction is returned to the liquid medium, this extraction-evaporation step being implemented using the at least one operating parameter of the extraction-evaporation system previously determined to separate a volatile fraction containing a determined quantity of biodegradable organic matter and obtain a mixture of the volatile fraction with the digestate or a liquid fraction of the digestate comprising biodegradable organic matter and ammonium ions according to the ratio value determined in step (b) of the determination method, - a bioelectrochemical treatment step during which electroactive microorganisms oxidize the biodegradable organic matter contained in the mixture of the volatile fraction with the digestate or its liquid fraction, at least part of the ammonium ions contained in the digestate or its liquid fraction migrates through the at least one separator and an effluent enriched in ammonium ions is extracted from the bioelectrochemical treatment system.

[0016] This method thus makes it possible to recover a target value of ammonium ions, which can be optimized, while optimizing the production of biogas. In addition, the bioelectrochemical treatment step makes it possible to treat the nitrogen present in the digestate at a lower cost since a sufficient quantity of biodegradable organic matter is introduced to migrate the ammonium ions present in the digestate or its liquid fraction. In particular, the method according to the invention makes it possible to limit the accumulation of biodegradable organic matter in the enclosure containing the liquid medium. This can make it possible to promote subsequent methanogenesis reactions and the production of biogas, in particular when the enclosure containing the liquid medium is part of an anaerobic biological system, for example is a fermenter of a two-phase digestion system.

[0017] In one embodiment, the anaerobic biological treatment step may comprise a first phase implemented in a fermenter, advantageously to carry out hydrolysis and acidogenesis, and a second phase implemented in a digester to produce biogas and digestate, advantageously by acetogenesis and methanogenesis, in particular under conditions of maximizing biogas production. The liquid medium is then the contents of the fermenter.

[0018] In one embodiment of the biological treatment method: - the determining step can further determine at least one operating parameter of the bioelectrochemical treatment system, and - during the bioelectrochemical treatment step, the bioelectrochemical treatment system is implemented using at least one operating parameter of the bioelectrochemical treatment system determined during the determination step.

[0019] The invention also relates to a system for determining at least one operating parameter of a biological treatment installation as previously described receiving an input containing carbonaceous material and nitrogen compounds, the system comprising: - means for acquiring (ai) a value of at least one parameter representative of the capacity of the electrochemical treatment system to separate ammonium ions, and (aii) a value of at least one quality parameter of the digestate or its liquid fraction, representative of a quantity of ammonium ions relative to a total quantity of cations, - first determination means adapted to determine a value of a characteristic ratio of the mixture of said volatile fraction with the digestate or its liquid fraction, representative of a quantity of biodegradable organic matter relative to a quantity of ammonium ions, as a function of (bi) a target yield of ammonium ions extracted from the bioelectrochemical treatment system or a target concentration of separated ammonium ions present in the bioelectrochemical treatment system, and (bii) the values received from the acquisition means, - second determination means adapted to determine at least one operating parameter of the extraction-evaporation system as a function of the value of the ratio determined by the first determination means, the at least one operating parameter being chosen from the evaporation temperature, the evaporation pressure, the frequency of extraction of the portion from the liquid medium, the flow rate of the portion extracted from the liquid medium.

[0020] The determination system may comprise at least one of the following characteristics: - the acquisition means are means for acquiring at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions chosen from at least one parameter representative of the capacity of the at least one separator to allow the ammonium ions to pass, and a parameter representative of a concentration gradient of the cations on either side of the at least one separator, - the acquisition means are adapted to estimate or determine from intrinsic characteristics of the at least one separator the value of at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions which is at least one parameter representative of the capacity of the at least one separator to allow ammonium ions to pass through, - the acquisition means are adapted to estimate or calculate the value of at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions which is at least one parameter representative of a concentration gradient of the cations on either side of the at least one separator, - the acquisition means are adapted to estimate or calculate the value of at least one quality parameter of the digestate or its liquid fraction as a function of the concentration of the digestate or its liquid fraction in ammonium ions, and of its conductivity or its total concentration in cations, - the first determination means are adapted to determine the target yield of extracted ammonium ions or the target concentration of separated ammonium ions as a function of a subsequent treatment of an effluent containing the ammonium ions extracted from the at least one recovery compartment, this treatment being chosen from struvite precipitation and stripping, - the first determination means are adapted to determine a characteristic ratio of the mixture chosen from the C / N ratio of the quantity of carbon to the quantity of nitrogen, the COD / NH4+ ratio of the chemical oxygen demand to the concentration of ammonium ions, the AGV / NH4+ ratio of a concentration of volatile fatty acids to the concentration of ammonium ions, the DB05 / NH4+ ratio of the biological oxygen demand at 5 days to the concentration of ammonium ions.

[0021] The second determining means may be adapted to determine at least one operating parameter of the bioelectrochemical treatment system as a function of the value of the ratio determined in step (b), of the value of at least one quality parameter of the digestate or of its liquid fraction acquired in step (a), the at least one operating parameter of the bioelectrochemical treatment system being chosen from the residence time of the digestate or of its liquid fraction in the at least one anode compartment, the flow rate of effluent enriched in ammonium ions extracted from the bioelectrochemical treatment system, a potential difference applied to the bioelectrochemical treatment system.

[0022] This determination system typically comprises a computer, or more generally at least one processor or any other type of digital calculator. The determination system may also comprise a plurality of separate processors or digital calculators, forming different means of the system, cooperating with each other.

[0023] Finally, the invention also relates to an installation for the biological treatment of an input containing carbonaceous material and nitrogen compounds to produce biogas and recover ammonium ions, the installation comprising: - an anaerobic biological system producing biogas and digestate, - an extraction-evaporation system adapted to extract a portion of the contents of a liquid medium containing biodegradable organic matter and to separate it by evaporation into a volatile fraction containing volatile organic matter and a concentrated fraction returned to the liquid medium, - a bioelectrochemical treatment system receiving the digestate or a liquid fraction thereof and said volatile fraction, this bioelectrochemical treatment system comprising electroactive microorganisms and at least one separator capable of allowing ammonium ions to pass when a potential difference is applied.

[0024] According to the invention, the installation further comprises: - a system for determining at least one operating parameter according to the invention, - a system for regulating the at least one operating parameter adapted to receive the at least one operating parameter from the determination system and to modify the corresponding operating parameter of the extraction-evaporation system, and optionally of the bioelectrochemical treatment unit, using the at least one operating parameter determined by the determination system.

[0025] In one embodiment, the anaerobic biological system may be a two-phase anaerobic digestion system as previously described. Definitions

[0026] By electroactive microorganisms is meant microorganisms capable of exchanging electrons with solid and conductive surfaces.

[0027] BOD: Biological Oxygen Demand (quantity of oxygen required to oxidize all organic (biodegradable) matter biologically)

[0028] DBO5: Biological oxygen demand measured after 5 days

[0029] COD or DCOtot: Chemical oxygen demand (measurement of the totality of oxidizable substances, whether biodegradable or not). COD can be measured according to the NFT 90-101-February 2001 or ISO 6060-1989 standard.

[0030] The methanogenic potential (noted BMP) corresponds to the maximum quantity of methane produced by a compound during its degradation.

[0031] The term "evaporation" refers to the general process by which any substance passes from the liquid state to the gaseous state. When the liquid contains water, the resulting gas may contain more or less vapor depending on the evaporation conditions. Thus, the term "evaporation" includes degassing where the gaseous phase is composed mainly of incondensable products, possibly saturated with water. The term "evaporation" also includes processes in which the gaseous phase is composed mainly of vapor and non-condensable products. Detailed description of the invention

[0032] Other features and advantages of the invention will emerge from reading the description given below of a particular embodiment of the invention, given for information purposes, but not as a limitation, with reference to the appended drawings in which:

[0033] [Fig. 1] is a schematic representation of a biological treatment installation according to one embodiment of the invention;

[0034] [Fig.2] is a schematic representation of a biological treatment facility according to one embodiment comprising a two-phase anaerobic digestion system coupled to an extraction-evaporation system and a bioelectrochemical treatment system;

[0035] [Fig.3] is a partial representation of an installation according to an embodiment of the invention,

[0036] [Fig.4] is a flowchart of the determination method according to one embodiment of the invention.

[0037] In the figures, the same elements are designated by the same references.

[0038] The present invention relates to a treatment installation and method biological processing of an input containing carbonaceous matter and nitrogen compounds in order to produce biogas, and in particular methane, while recovering the nitrogen present in the input, in order to use it.

[0039] For this purpose, the invention uses a system and a method for determining at least one operating parameter of a biological treatment installation comprising an anaerobic biological system, for example a two-phase anaerobic digestion system, an extraction-evaporation system and a bioelectrochemical treatment system coupled to the anaerobic biological system, directly or via a phase separation system and / or a purification system, and also coupled to the extraction-evaporation system. In particular, the system and the method make it possible to determine at least one operating parameter of the extraction-evaporation system of the installation, and optionally at least one operating parameter of the bioelectrochemical treatment system.

[0040] Biological treatment installation

[0041] The system and the determination method according to the invention are suitable for determining at least one operating parameter of an installation comprising: - an anaerobic biological system producing biogas and digestate, and - an extraction-evaporation system suitable for extracting a portion of the contents of a liquid medium containing biodegradable organic matter and for separating it by evaporation into a volatile fraction containing volatile organic matter and into a concentrated fraction returned to the liquid medium, - a bioelectrochemical treatment system receiving the digestate or a liquid fraction thereof and said volatile fraction, this bioelectrochemical treatment system comprising electroactive microorganisms and at least one separator capable of allowing ammonium ions to pass when a potential difference is applied.

[0042] The installation may further comprise an enclosure containing the liquid medium coupled to the extraction-evaporation system.

[0043] In a preferred embodiment, the enclosure containing the liquid medium may be part of an anaerobic biological system, for example a two-phase anaerobic digestion system comprising a fermenter implementing a first phase, typically a first phase of hydrolysis and acidogenesis, and a digester implementing a second phase producing biogas and a digestate, typically a second phase of acetogenesis and methanogenesis. The enclosure containing the liquid medium is then the fermenter.

[0044] The liquid medium from which the extraction-evaporation system takes a portion to separate it by evaporation may be any liquid medium, typically aqueous, containing biodegradable organic matter. As previously described, this biodegradable organic matter may comprise volatile fatty acids and possibly low molecular weight fermentation compounds (alcohols, etc.). It may in particular be a sludge, advantageously partially digested. The liquid medium may in particular also comprise microorganisms and / or enzymes, and optionally other volatile substances, such as, but not limited to, carbon dioxide, ammonia, hydrogen sulfide or other odorous compounds reduced to the sulfur state. The liquid medium may be the contents of an enclosure forming part of an anaerobic biological system, which may or may not be the one producing the biogas and digestate of the present invention.In a preferred embodiment, the liquid medium is the contents of a fermenter of a two-phase anaerobic digestion system.

[0045] The extraction-evaporation system may comprise at least one evaporator adapted to separate said volatile fraction and the concentrated fraction, and optionally one or more pipes, valves and / or pumps. The liquid fraction containing water vapor, ammonia and other volatile substances, such as volatile fatty acids, is collected and sent to the bioelectrochemical treatment system, optionally after condensation and / or treatment with a liquid effluent.

[0046] The extraction-evaporation system may further comprise one or more of the following devices: - at least one condenser adapted to separate said volatile fraction into a condensable fraction and a non-condensable fraction sent to the bioelectrochemical treatment system, - at least one treatment device in which either the volatile fraction or the non-condensable fraction of this volatile fraction is treated with a liquid effluent in order to extract the biodegradable organic matter and capture it in the liquid effluent which is then sent to the bioelectrochemical treatment system.

[0047] In one embodiment, the extraction-evaporation system may in particular comprise a pipe for extracting a portion of the contents of the liquid medium, an evaporator of this portion into a volatile fraction containing volatile organic matter and a concentrated fraction, and a pipe for returning the concentrated fraction to the liquid medium.

[0048] The bioelectrochemical treatment system is particularly suitable for treating the digestate or a liquid fraction thereof. Thus, the electroactive microorganisms are selected from microorganisms capable of oxidizing the biodegradable organic matter of the digestate or its liquid fraction. This selection may be a selection of a pure strain added voluntarily to the system or a selection by a biological process from a mixed microbial culture.

[0049] The ammonium ions separated during the application of a potential difference can typically be extracted from the bioelectrochemical treatment system, for example by an extraction system. This extraction system comprises for example a pipe connected to a pump or any other device allowing the withdrawal of a fluid.

[0050] Typically, the bioelectrochemical treatment system may comprise at least one recovery compartment equipped with an extraction system, and electroactive microorganisms capable of oxidizing by releasing electrons the biodegradable organic matter contained in the mixture of said volatile fraction with the digestate or its liquid fraction. These microorganisms are typically separated from the at least one recovery compartment by the at least one separator capable of allowing ammonium ions to pass through so that, under the application of a potential difference, the ammonium ions contained in the digestate or its liquid fraction migrate through the separator to through the separator, for example towards a recovery compartment.

[0051] Examples of embodiments of this installation are described below with reference to Figures 1 to 3.

[0052] As shown in Figures 1 and 2, the treatment facility 100 comprises an anaerobic biological system 110, adapted to produce biogas and digestate, an extraction-evaporation system 160 and a bioelectrochemical treatment system 120 adapted to treat the digestate or a liquid fraction thereof.

[0053] As shown [Fig. 1], the anaerobic biological system 110 may have an inlet 111 through which the input 1 to be treated enters, an outlet 112 for evacuating the biogas 2 product and an outlet 113 to evacuate the digestate 3 product.

[0054] The installation 100 shown [Fig.l] further typically comprises an enclosure 101 in which there is a liquid medium containing biodegradable organic matter.

[0055] This enclosure 101 comprises an outlet 114 and an inlet 115 connected to the extraction-evaporation system 160.

[0056] The anaerobic biological system may be adapted to implement a one- or two-phase anaerobic biological treatment step.

[0057] In the embodiment of [Fig.2], the enclosure containing the liquid medium is part of the anaerobic biological system which is, in this example, a two-phase anaerobic digestion system 110.

[0058] This anaerobic digestion system 110 comprises a fermenter 110-1 implementing a first phase, for example a hydrolysis and acidogenesis phase, and a digester 110-2 implementing a second phase producing the biogas 2 and the digestate 3, for example a second phase of acetogenesis and methanogenesis and.

[0059] The fermenter 110-1 is an enclosure containing the liquid medium within the meaning of the invention and typically comprises the inlet 11 through which the input 1 to be treated enters and an outlet 110-11 for the sludge 1' leaving the first phase of the anaerobic digestion step. It also comprises the outlet 114 and the inlet 115 connected to the extraction-evaporation system 160. This fermenter 110-1 can be operated under conditions adapted to implement the first phase, typically to maximize the hydrolysis and acidogenesis reactions, while limiting the acetogenesis and methanogenesis reactions. This can be obtained in a manner known to those skilled in the art via a control of the residence time.

[0060] The digester 110-2 typically comprises an inlet 110-21 through which the sludge 1' from the fermenter 110-1 enters, the outlet 112 of biogas 2 and the outlet 113 of the digestate 3. This digester 110-2 can be operated under conditions adapted to implement the second phase, typically to maximize the acetogenesis and methanogenesis reactions, and thus the production of biogas, in particular methane. This can be obtained in a manner known to those skilled in the art via control of the residence time.

[0061] Regardless of the embodiment, each of the enclosure 101, the fermenter 110-1 and the digester 110-2 may comprise one or more bioreactors mounted in parallel or in series adapted for implementing anaerobic digestion in one or two phases in the presence of suitable microorganisms. These may be bioreactors with continuous, semi-continuous or discontinuous feed ("batch"). For example, a sequential reactor also called an SBR reactor (Sequential Batch Reactor), a mixed culture reactor with continuous feed (Meteor™-IFAS), a fixed or free culture reactor, ...

[0062] The extraction-evaporation system 160 is adapted to extract a portion 6 of the contents of the enclosure 101 or the fermenter 110-1 and to separate it by evaporation into a volatile fraction 7 containing volatile organic matter and into a concentrated fraction 8 returned to the enclosure 101 or to the fermenter 110-1. For this purpose, the extraction-evaporation system may comprise at least one evaporator 162. The extraction-evaporation system 160 may further comprise one or more pipes, valves and / or pumps.

[0063] In one embodiment, as shown in Figures 1 and 2, the extraction-evaporation system 160 may comprise an extraction pipe 161 for a portion 6 of the contents of the enclosure 101 or the fermenter 110-1, an evaporator 162 for this portion into a volatile fraction 7 containing volatile organic matter and a concentrated fraction 8, and a return pipe 163 into the enclosure 101 or the fermenter 110-1 for the concentrated fraction. The evaporator 162 then comprises an inlet 162a receiving the portion 6, an outlet 162b for the concentrated fraction and an outlet 162c for the volatile fraction 7. The latter is connected to the biological treatment system 120.

[0064] The evaporator 162 may include one or more reservoirs, one or more containers, or one or more devices that may be used in part for evaporation reactions for the removal of solutes or solvents. Water is a typical solvent and volatile compounds are typical solutes. Both of these reactions are governed by physical laws. The hydraulic retention time of an evaporator is often on the order of minutes or hours. The evaporator may be under negative pressure (with the digester pressure serving as a reference) or under vacuum.

[0065] The evaporator 162 may be a forced circulation evaporator, a rising or falling film evaporator, an agitated thin film evaporator, a multiple effect evaporator, a self-cleaning evaporator, or a flash evaporator, also known as a flash cooling process, or any other evaporation system. This evaporator may act as a degassing tank when the operating temperature is above the boiling point of the extracted portion of the digester, or as a boiler when the operating temperature is equal to or below the boiling point of the extracted portion of the digester.

[0066] The evaporator 162 is generally equipped with a system for limiting and controlling the evaporation pressure and temperature within the evaporator, for example, vacuum generating equipment, such as a vacuum pump, connected to the headspace of the evaporator.

[0067] The evaporator 162 is preferably external to the enclosure 101 or to the fermenter 110-1 and is a separate device from these. This allows different materials of construction to be used for a generally larger enclosure or fermenter, which may be under atmospheric or positive pressure, and for a generally smaller evaporator, which may be under vacuum or negative pressure (the pressure of the enclosure or fermenter being used as a reference).

[0068] The digestate 3 then enters via an inlet 121 into the bioelectrochemical treatment system 120. The latter also comprises an inlet 121' for the volatile fraction 7 coming from the evaporator 162, a first outlet 122 for evacuating the treated digestate 4, a second outlet 123 for evacuating an effluent 5 enriched in ammonium ions. However, provision may be made for the volatile fraction 7 to enter the bioelectrochemical treatment system 120 via the same inlet as the digestate 3.

[0069] In the embodiment shown [Fig.3], the extraction-evaporation system 160 comprises an evaporator 162, and a condenser 164 receiving the volatile fraction 7 evaporated by the evaporator 162 and / or at least one device 165 for treating the volatile fraction 7 or a non-condensable fraction of the volatile fraction 7. These different devices are connected by one or more pipes, valves and / or pumps.

[0070] This treatment device 165 is adapted to capture in a liquid effluent 9 the biodegradable organic matter contained in the volatile fraction or a non-condensable fraction thereof. It is then the liquid effluent comprising the captured biodegradable organic matter leaving the treatment device 165 which is sent to the bioelectrochemical treatment system.

[0071] The condenser 164 is typically connected to a source of cold fluid (not shown) and comprises a first outlet 164a for a condensable fraction 7'a and a second outlet 164b for a non-condensable fraction 7'b. The condensable fraction 7'a typically contains water, and optionally other volatile substances that partially condense or dissolve in the water, such as ammonia, CO2, sulfur compounds or volatile fatty acids. The non-condensable fraction 7'b contains the biodegradable organic matter, typically VFAs, and optionally ammonia and / or dihydrogen and / or CO2 and / or methane.

[0072] The volatile fraction 7, or its non-condensable fraction 7'b, can be sent directly to the bioelectrochemical treatment system 120 or can advantageously undergo treatment with a liquid effluent 9 in the treatment device 165 (also called a "scrubber") in order to produce a liquid stream 10 containing the liquid effluent and the biodegradable organic matter and a gaseous stream 11, containing for example dihydrogen, and / or ammonia and / or CO2 and / or methane. The liquid effluent 9 is thus chosen according to the nature of the biodegradable organic matter to be captured. When the latter essentially contains VFAs, the liquid effluent 9 can be a basic aqueous medium, for example an aqueous sodium hydroxide solution. Suitable solvents can also be considered; however, it is preferable to use a basic aqueous medium. It is then the liquid stream 10 which is sent to the bioelectrochemical treatment system.

[0073] The treatment device 165 may be a washing device or a scrubber such as a spray tower, a venturi scrubber, a membrane scrubber or any other type of scrubber.

[0074] In some embodiments, the facility 100 may comprise one or more optional digestate treatment systems 140, configured to separate a liquid fraction 3a from the digestate 3 before its treatment in the bioelectrochemical treatment system and / or to remove impurities from the digestate before its entry into the system 120. The optional treatment system 140 may thus be a phase separation system typically comprising one or more decanters or clarifiers or filters. The optional treatment system 140 may also be a system for removing impurities, for example by screening.

[0075] The bioelectrochemical treatment system 120 comprises at least one separator 124 capable of allowing ammonium ions to pass through. It further comprises at least one recovery compartment 125 equipped with an extraction system 126 (here comprising a pipe 126a connected to a pump 126b), and electroactive microorganisms capable of oxidizing by releasing electrons the biodegradable organic matter contained in the mixture of the volatile fraction 7 with the digestate 3 or with its liquid fraction 3a and separated from the recovery compartment 125 by the separator 124 so that, under the application of a potential difference, the ammonium ions contained in the digestate or its liquid fraction migrate through the separator towards the recovery compartment.

[0076] Generally, the separator allows the passage of ions (cations or anions) between the anodic and cathodic compartments. It may comprise one or more ion exchange membranes, a porous ceramic material allowing the passage of ions, or other. When it has two ion exchange membranes, it may further comprise an inter-membrane compartment.

[0077] As shown in Figures 1 and 2, the bioelectrochemical treatment system 120 typically comprises at least one anode compartment 127 coupled to the anaerobic biological system 110 or to the digester 110-2 so as to receive the digestate or a liquid fraction thereof, and in which there are electroactive microorganisms capable of oxidizing the organic matter of the digestate and its liquid fraction. This anode compartment 127 is also coupled to the extraction-evaporation system 160, and in particular to its evaporator 162. The bioelectrochemical treatment system further comprises at least one compartment ca 128, at least one ammonium ion extraction system 126, and optionally at least one intermediate compartment 129 (e.g. an intermembrane compartment), these different compartments being separated by separators. In addition, in the usual manner, it typically comprises at least one electrode 130 in each of the anode and cathode compartments as well as means 131 for applying a potential difference between the anodes and cathodes.

[0078] In a preferred embodiment shown [Fig.2], the bioelectrochemical treatment system 120 comprises an intermediate or inter-membrane compartment 129, which is located between the anode compartment 127 and the cathode compartment 128. The separator 124 capable of allowing ammonium ions to pass is then located between the anode compartment 127 and the intermediate compartment 129 which serves as a recovery compartment 125 and is equipped with the extraction system 126. Another separator 124' separates the recovery compartment 125, 129 from the cathode compartment 128. The effluent 5 rich in ammonium ions is extracted from the intermediate compartment 125, 129 via the extraction system 126.

[0079] In another embodiment (shown [Fig.l]), the bioelectrochemical treatment system 120 does not include an intermediate compartment 129. In this case, the ammonium ion recovery compartment 125 serves as the cathode compartment 128 and is equipped with the extraction system 126. The separator 124 capable of allowing ammonium ions to pass then separates the anode 127 and cathode 128, 125 compartments. The effluent 5 rich in ammonium ions is extracted from the cathode compartment via the extraction system 126.

[0080] Regardless of the embodiment, the bioelectrochemical treatment system 120 may comprise at least one bioelectrochemical reactor - in particular a microbial electrolysis or electrosynthesis reactor.

[0081] A reactor in which only the anode compartment comprises electroactive microorganisms may be used, in particular in an abiotic bio-anode / cathode configuration, to couple the treatment of organic matter from the digestate in the anode compartment (by bio-electrochemical oxidation of the COD), either with the production of H2 from H2O at the cathode in the case of a microbial electrolysis process, or with a reduction of O2 at the cathode for a microbial cell.

[0082] Alternatively, a reactor may be used whose anode and cathode compartments contain electroactive microorganisms. By operating as a microbial electrolyzer, this type of reactor can be used in bioelectrosynthesis processes coupling treatment of the digestate at the anode and synthesis of carbon molecules at the cathode. By operating as a microbial fuel cell, this type of reactor can be used to couple treatment of the digestate at the anode with denitrification treatment at the cathode of the digestate or another effluent.

[0083] In one embodiment, the bioelectrochemical treatment system can thus be used as a microbial fuel cell to produce electric current. In another embodiment, the bioelectrochemical treatment system can be used as an electrolysis system or a microbial electrosynthesis system. It can then be used to produce dihydrogen (H2) or chemical molecules of interest (methane, organic acids, alcohol, etc.). When methane is produced, the total quantity of methane produced by the installation according to the invention can be increased.In this case, the at least one cathode compartment comprising electroactive microorganisms may comprise at least one inlet for a carbon source, typically injected in the form of gas, such as CO2, biogas, or syngas, and / or introduced in solution in the form of organic carbon, for example acetate, and / or in the form of mineral carbon, in particular a bicarbonate.

[0084] In general, electroactive microorganisms are present in the form of a biofilm on the surface of the electrode. The latter may be flat, brush-shaped or in granular form, in a fixed or fluidized bed. Examples of reactors that can be used are described in documents FR3123347A1 and WO2020 / 053529A1.

[0085] Regardless of the embodiment, the separator may comprise a cation exchange membrane and an anion exchange membrane separated from each other by an inter-membrane compartment comprising a system for extracting molecules (typically soluble molecules) present within the compartment. The inter-membrane compartment is thus capable of collecting the ions or molecules produced in the anodic and / or cathodic compartments. The molecules recovered at this inter-membrane compartment comprise, for example, ammonium salts, and, depending on the composition of the digestate, other salts such as phosphate salts or others.

[0086] When such an inter-membrane compartment is present, the membranes can be positioned so that the anode compartment is separated from the cathode compartment by, going from the anode compartment to the cathode compartment, a cation exchange membrane and an anion exchange membrane. For example, it is then possible to recover carboxylic acids synthesized at the cathode, as well as cations (eg NH4+) from the anode compartment.

[0087] The electrochemical treatment system may comprise a multistack type structure, with a (horizontal) succession of an anodic compartment, a first intermembrane compartment, a cathodic compartment, a second intermembrane compartment, it being understood that one end of this succession is an anode, and the other is a cathode.

[0088] The biological treatment installation according to the invention may further comprise a or several treatment systems 150 for the effluent 5 rich in ammonium ions leaving the bioelectrochemical treatment system 120, making it possible in particular to separate and purify the nitrogen contained in the effluent. This system 150 may comprise one or more columns adapted to carry out stripping of the nitrogen followed by absorption, or one or more reactors adapted to precipitate the ammonium ions in the form of struvite.

[0089] According to the invention, the installation 100 comprises a system 200 for determining at least one operating parameter configured to implement the determination method according to the invention, as well as a regulation system 300 adapted to receive the at least one operating parameter from the determination system, and to modify the corresponding operating parameter of the extraction-evaporation system 160, and optionally of the bioelectrochemical treatment system, using the at least one operating parameter determined by the determination system.

[0090] The determination system 200 is described in detail below. It typically comprises one or more processors, for example microprocessors or microcontrollers. The processor(s) may have storage means which may be a random access memory (RAM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, an external memory or the like. These storage means may, among other things, store received data, a control model and one or more computer programs. The determination system 200 also comprises communication means, optionally bidirectional, with the regulation system 300 and / or with sensors and / or measuring and / or determination means.

[0091] The regulation system 300 typically comprises means for adjusting the operating parameters of the installation, and in particular of the extraction-evaporation system 160, and optionally of the bioelectrochemical treatment system. These adjustment means are, for example, valves, pumps, a liquid medium heating system, a pressure gauge, etc., in communication with the determination system.

[0092] The regulation system can thus typically comprise valves, solenoid valves, pumps, regulating the quantities of fluids entering and leaving the extraction-evaporation system 160, and optionally from the bioelectrochemical treatment system, a system for maintaining the temperature and / or pressure of the evaporator 162, one or more sensors, chosen from a temperature sensor of the evaporator 162, a pressure sensor of the evaporator 162, a flow rate sensor of the flows entering and leaving the evaporator 162, and optionally from the bioelectrochemical treatment system, a sensor for measuring the nitrogen content of the input, a measuring sensor organic matter of the digestate or a liquid fraction thereof, a sensor for measuring the content of cations and / or ammonium ions of the digestate or a liquid fraction thereof, cooperating with each other and with the determination system.

[0093] The regulation system may further comprise a control loop making it possible to modify the operating parameter(s) as a function of data received from the sensors and operating parameter(s) received from the determination system.

[0094] Method and system for determining at least one operating parameter

[0095] As shown schematically [Fig.4], the determination method according to the invention comprises: (a) a step of acquiring (ai) a value of at least one parameter representative of the capacity of the electrochemical treatment system to separate ammonium ions, and (aii) a value of at least one quality parameter of the digestate or its liquid fraction, (b) a step of determining a value of a ratio characteristic of the mixture of said volatile fraction with the digestate or its liquid fraction determined as a function of (bi) a target yield of ammonium ions extracted from the bioelectrochemical treatment system, for example extracted from the recovery compartment, or a target concentration of separated ammonium ions present in the bioelectrochemical treatment system, for example in the recovery compartment thereof, and (bii) the values acquired in step (a), (c) a step of determining at least one operating parameter of the extraction-evaporation system as a function of the value of the ratio determined in step (b).

[0096] Acquisition step (a) serves to acquire, by measurement, modeling or empirically, the values of at least one parameter representative of the capacity of the electrochemical treatment system to separate ammonium ions and of at least one quality parameter of the digestate or its liquid fraction.

[0097] The at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions may in particular comprise at least one parameter representative of the capacity of the at least one separator to allow the ammonium ions to pass, and a parameter representative of a concentration gradient of the cations on either side of the at least one separator.

[0098] The parameter representing the capacity of the at least one separator to allow ammonium ions to pass typically depends on the intrinsic properties of the separator. It is in particular typically linked to the diffusion coefficient of the separator and to its thickness. The value of this parameter can be determined, in particular calculated, from of diffusion coefficient values and the dimensions of the separator, or else be estimated empirically or by means of a model, for example based on Fick's law. When it is estimated, it could for example be a loss parameter expressed as a percentage and representing a rate of ammonium ions which can pass through the separator.

[0099] The parameter representative of a concentration gradient of the cations on either side of the at least one separator depends on the flows entering and leaving the electrochemical treatment system. The value of this parameter can thus be estimated from a model or empirically, or else determined, in particular by calculation, for example as a function of an extraction rate of the ammonium ions (or of the effluent 5 enriched in ammonium ions) from the bioelectrochemical treatment system, of the residence time of the digestate or of its liquid fraction inside the bioelectrochemical treatment system.

[0100] The at least one quality parameter of the digestate or its liquid fraction is a parameter representative of a quantity of ammonium ions relative to a total quantity of cations. The value of this parameter may be estimated, in particular by means of a model or empirically, or measured as a function of the concentration of ammonium ions in the digestate or its liquid fraction, and of its conductivity or its total concentration of cations. For example, the ratio of its concentration of ammonium ions to its conductivity or the ratio of its concentration of ammonium ions to its total concentration of cations, measured for example by ion chromatography, may be used as a parameter. When estimated, this parameter may be a safety coefficient taking into account the non-specificity of ion migration within the system, the value of which is for example between 0 and 1, in particular between 0.2 and 1.

[0101] Thus, the acquisition step (a) may comprise a step of receiving parameter values, and optionally a step of determining parameter values.

[0102] During step (a), other operating parameters of the bioelectrochemical treatment system may also be acquired, such as a potential difference applied or applicable to the bioelectrochemical treatment system, and / or the residence time of the digestate or its liquid fraction in the bioelectrochemical treatment system, and / or the flow rate of effluent enriched in ammonium ions extracted from the bioelectrochemical treatment system. It is then possible to carry out this determination as a function of a particular bioelectrochemical treatment system that one wishes to use, and in particular of its dimensions and the operating parameter ranges used for this particular system.In this case, it is not necessary to control the operating parameters of the bioelectrochemical treatment system to enable the desired recovery of the amount of ammonium ions during the bioelectrochemical treatment step, since the ratio determined during this . step (b) is applicable to the different possible operating conditions of the particular bioelectrochemical treatment system.

[0103] During step (a), other quality parameters of the digestate or its liquid fraction may also be optionally acquired, such as its temperature and the fraction of non-hydrolyzed methanization substrate. The temperature will have a direct effect on the microbial kinetics of the anodic biofilm while the fraction of non-hydrolyzed methanization substrate corresponds to a potential biodegradable substrate for the bioelectrochemical treatment system.

[0104] Step (a) can be implemented by acquisition means 210 of the determination system 200, adapted to acquire (ai) the value of the at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions, and (aii) the value of the at least one quality parameter of the digestate or of its liquid fraction, representative of a quantity of ammonium ions relative to a total quantity of cations. These acquisition means 210 are optionally also adapted to implement the different embodiments of step (a) previously described.

[0105] These acquisition means 210 may comprise one or more processors and memories, in particular for storing values and models, and / or means of communication, in particular with sensors and / or means of measuring and / or determining values of the aforementioned parameters.

[0106] Step (b) makes it possible to determine the value of a characteristic ratio of the mixture of said volatile fraction with the digestate or its liquid fraction as a function of (bi) a target yield of ammonium ions extracted from the bioelectrochemical treatment system, for example from its recovery compartment, or a target concentration of separated ammonium ions present in the bioelectrochemical treatment system, for example in its recovery compartment, and (bii) the values of the at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions and of the at least one quality parameter acquired in step (a). This step involves determining the quantity of biodegradable material that the microorganisms of the bioelectrochemical treatment system must degrade to release enough electrons to ensure the passage of a target quantity of ammonium ions to the other side of the at least one separator.This quantity of biodegradable material can, for example, be estimated by material balance or determined by a kinetic model taking into account the phenomena of ionic migration and diffusion within the bioelectrochemical treatment system, these methods being well known in bioelectrochemistry.

[0107] This ratio can for example be chosen from the C / N ratio of the quantity of carbon to the quantity of nitrogen, the COD / NH4+ ratio of the chemical oxygen demand to the ammonium ion concentration, the VFA / NH4+ ratio of a volatile fatty acid concentration to the ammonium ion concentration and the DB05 / NH4+ ratio of the 5-day biological oxygen demand to the ammonium ion concentration. VFA and NH4+ concentrations can be determined by conventional acid-base titrations.

[0108] For example, the COD / NH4+ ratio can be from 0.25 to 10 gCOD / gN.

[0109] The target yield of extracted ammonium ions or the target concentration of separated ammonium ions can be determined as a function of the desired quality of effluent enriched in ammonium ions and / or as a function of the desired quality for the digestate or its liquid fraction, for example if the nitrogen content is desired to be below a threshold.

[0110] The target yield of extracted ammonium ions or the target concentration of separated ammonium ions can also be determined as a function of a subsequent treatment of an effluent containing the ammonium ions extracted from the bioelectrochemical treatment system, and in particular of a treatment such as struvite precipitation, or stripping. Those skilled in the art will be able to determine these thresholds as a function of the technology used.

[0111] Step (b) can be implemented by first determination means 220 of the determination system 200, adapted, in particular programmed, to determine the value of a characteristic ratio of the digestate or of its liquid fraction, representative of a quantity of biodegradable organic matter relative to a quantity of ammonium ions, and to determine this value as a function of (bi) a target yield of ammonium ions extracted from the bioelectrochemical treatment system, for example in its recovery compartment, or a target concentration of separated ammonium ions present in the bioelectrochemical treatment system, for example in its recovery compartment, and (bii) the values of the at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions and of the at least one quality parameter received from the acquisition means.These first determination means 220 may optionally also be adapted, in particular programmed, to implement the different embodiments of step (b). These first determination means 220 may comprise one or more processors and one or more memories for storing the determined values, and optionally models.

[0112] Step (c) makes it possible to determine at least one operating parameter of the extraction-evaporation system as a function of the value of the ratio determined in step (b). This operating parameter is chosen from the evaporation temperature, the evaporation pressure, the frequency of extraction of the portion from the liquid medium, the flow rate of the portion extracted from the liquid medium.

[0113] The evaporation temperature may be the operating temperature of the evaporator. It is typically within the operating temperature range of the enclosure containing the liquid medium or at a lower or higher temperature. It will be noted that when the enclosure is the fermenter of a two-phase digestion system, it may operate in a temperature range of 15 to 70°C. It may thus be a mesophilic fermenter, typically operating from 30 to 45°C, or a thermophilic fermenter, typically operating from 45 to 70°C.

[0114] The evaporation pressure may be the pressure inside the evaporator. Typically, this pressure is 33 to 800 millibars absolute pressure.

[0115] The operating parameter(s) of the extraction-evaporation system may be determined using models or charts, in particular so as to separate a volatile fraction containing a determined quantity of biodegradable organic matter and thus obtain a mixture of the volatile fraction with the digestate or a liquid fraction of the digestate comprising biodegradable organic matter and ammonium ions according to the ratio value determined in step (b). These charts may be produced from experimental measurements or found in the literature. These models or charts may advantageously take into account characteristics of the devices constituting the extraction-evaporation system, and in particular the evaporator, the condenser and / or the treatment device in order to obtain at the outlet of the extraction system, a flow 7, 7'b or 10 containing a determined quantity of biodegradable organic matter.

[0116] The operating parameter(s) of the extraction-evaporation system can be determined according to laws well known to those skilled in the art, such as: - The law of conservation of mass or Lavoisier's law, - The acid-base balance of the species to be extracted. The chemical equilibrium of acid dissociation can be written symbolically as AH A + H+, where the volatile AH form is a generic acid dissociating into its conjugate base A, and into the hydrogen ion proton H+. The balance of these chemical species AH, A and H+ between the enclosure containing the liquid medium and the extraction-evaporation system is a function of the pH. - Henry's law which makes it possible to determine in the extraction-evaporation system (gas phase) the content of AGVs extracted by the increase in pH of the concentrated fraction returned to the liquid medium. - Determination of the pH of this concentrated fraction, by measurement or calculation, for example as described by: Moscoviz, Roman, and Julie Jimenez. "Improving anaerobic digestion mass balance calculations through stoichiometry and usual substrate characterization." Bioresource Technology 337 (2021): 125402.

[0117] In one embodiment, step (c) may comprise the determination of at least one operating parameter of the extraction-evaporation system as a function of the value of the ratio determined in step (b) and the pH value of the concentrated fraction produced by the extraction-evaporation system. In this case, the acquisition step (a) may further comprise the acquisition (aiii) of a pH value of this concentrated fraction, this acquisition being able to be carried out by measurement and / or by calculation.

[0118] The ratio determined in step (b) of the method according to the invention can be determined so as to allow the desired recovery of ammonium ions, whatever the operating conditions of the bioelectrochemical treatment system. In this case, it is not necessary to control the operating parameters of the bioelectrochemical treatment system.

[0119] In certain embodiments, the ratio determined in step (b) is however not determined taking into account the operating parameters of the bioelectrochemical treatment system. In this case, step (c) may also comprise the determination of at least one operating parameter of the bioelectrochemical treatment system as a function of the value of the ratio determined in step (b), of the value of at least one quality parameter of the digestate or of its liquid fraction acquired in step (a). This operating parameter may be chosen from the residence time of the digestate or of its liquid fraction in the bioelectrochemical treatment system, the flow rate of effluent 5 enriched in ammonium ions extracted from the bioelectrochemical treatment system (for example from the at least one recovery compartment of the latter), and a potential difference applied to the bioelectrochemical treatment system.

[0120] The applied potential difference can be modified by changing the voltage applied to the bioelectrochemical treatment system operating as an electrolyzer, or by changing the resistance applied to the bioelectrochemical treatment system operating as a battery.

[0121] The operating parameter(s) of the bioelectrochemical treatment system can then be determined using charts or models, depending on the microorganisms used in the system. Models describing the link between microbial kinetics and electric current in bioelectrochemical systems are for example described in the following article: Desmond-Le Quéméner, E., Moscoviz, R-, Bemet, N., Marcus, A. Modeling of interspecies electron transfer in anaerobic microbial communities. Current Opinion in Biotechnology (2021).

[0122] Step (c) can be implemented by second determination means 230 of the determination system 200, adapted, in particular programmed to determine at least one operating parameter of the extraction-evaporation system 160 in function of the value of the ratio determined by the first determination means 220,1' at least one operating parameter comprising the evaporation temperature, the evaporation pressure, the frequency of extraction of the portion from the liquid medium, the flow rate of the portion extracted from the liquid medium. These second determination means 230 can optionally also be adapted, in particular programmed, to implement the different embodiments of step (c).

[0123] These second determination means 230 may comprise one or more processors and one or more memories for storing the determined values, and optionally models.

[0124] The previously described determination method and system 200 can be used in a biological treatment method as described below.

[0125] Biological treatment process

[0126] The method for biological treatment of an input containing carbonaceous matter and nitrogen compounds makes it possible to produce biogas, and in particular methane, while recovering the nitrogen present in the input, in order to recover it. The biological treatment method according to the invention can be implemented by means of a biological treatment installation as previously described.

[0127] Input

[0128] The method and the biological treatment installation according to the invention are suitable for treating an input containing carbonaceous material and nitrogen compounds. The carbonaceous material can be in dissolved, colloidal or particulate form.

[0129] This input may contain any carbonaceous material suitable for fermentation reactions, including, but not limited to, mining, agricultural, industrial or domestic derived materials, including virgin products or waste from any process producing carbonaceous material, including the organic fraction of municipal solid waste and sewage sludge.

[0130] The input containing carbonaceous materials may be, but is not limited to, a sludge produced in a liquid treatment train in a sewage treatment plant or any other sludge.

[0131] Such sludge may be, but is not limited to, primary sludge from the discharge of a primary clarification process, or biological sludge from a secondary biological process in wastewater treatment, such as, but not limited to, waste activated sludge, or a combination of primary sludge and biological sludge.

[0132] The primary sludge may have been previously thickened, for example to reach a dry matter content of 2 to 15% by mass.

[0133] The input used in the present invention may have been previously subjected to a or several sub-steps chosen from a thickening step, a filtration step (“screening”), a dehydration step, a heat treatment step and a dilution step.

[0134] This heat treatment step may comprise a thermal hydrolysis process (THP) and / or a hydrothermal carbonization process (HTC). In a THP process, the sludge, the dry matter content of which is generally between 12% and 25% by mass, is maintained at a temperature between 140°C and 170°C, generally for 30 to 60 minutes. The HTC process generally operates at temperatures between 180°C and 280°C for a period of several minutes to several hours in a non-oxidizing atmosphere.

[0135] The input used in the present invention may have a dry matter content of 1 to 50% by mass, preferably 1 to 40% by mass or 1 to 35% by mass, for example 2 to 15% by mass or 15 to 30% by mass, or 17 to 25% by mass, or in any interval defined by two of these limits. The dry matter content may be determined gravimetrically, for example following the protocol proposed in the following report: Standard Methods for the Examination of Water and Wastewater American Public Health Association, Washington, DC (2005).

[0136] The input also contains water. Any presence of water sufficient for the implementation of biological reactions within the anaerobic biological system is considered suitable.

[0137] The method according to the invention can in particular make it possible to treat inputs having high nitrogen contents.

[0138] Anaerobic biological treatment step

[0139] The anaerobic biological treatment step of the process may be carried out in an anaerobic biological system as previously described.

[0140] The anaerobic biological system can be operated under operating conditions that maximize biogas production.

[0141] This anaerobic biological treatment step can be carried out under mesophilic or thermophilic temperature conditions. The hydraulic residence time and the solids residence time can be from 5 to 100 days.

[0142] The anaerobic biological treatment step may be one-phase or two-phase.

[0143] Notably, in one embodiment, the anaerobic biological treatment step of the method is a two-phase anaerobic digestion step that may be implemented in a two-phase anaerobic biological system as previously described.

[0144] This operation in one or two phases, as well as the different reactions of hydrolysis, acidogenesis, acetogenesis and methanogenesis, are notably described in the standard NF ISO 19388. As defined in this standard, a phase corresponds to a particular metabolic pathway, a two-phase process thus being implemented according to two distinct metabolic pathways.

[0145] In particular, during the first phase of a two-phase step, a fermenter is implemented, typically to carry out hydrolysis and acidogenesis, and during the second phase a digester is implemented to produce biogas and digestate, typically by acetogenesis and methanogenesis.

[0146] The fermenter and the digester can then be operated under the usual operating conditions to maximize the biogas production of the system. Under these conditions, the implementation of the first phase, for example via hydrolysis and acidogenesis reactions, in the fermenter typically makes it possible to produce a quantity of biodegradable organic matter (VFAs and / or alcohols) sufficient to allow extraction of the quantity necessary for the implementation of the bioelectrochemical treatment step. Thus, a portion of this biodegradable organic matter is taken by the extraction-evaporation system to feed the bioelectrochemical treatment system, the remainder being transformed totally or in part during the implementation of the second phase, for example via acetogenesis and methanogenesis reactions.

[0147] Advantageously, the part of this biodegradable organic matter taken by the extraction-evaporation system provides the bioelectrochemical treatment system with all of the biodegradable organic matter that it needs.

[0148] It may nevertheless happen that biodegradable organic matter remains in the digestate. This remaining quantity, for example determined by models and / or experiments, may then be taken into account during determination step c). Step (c) may then comprise a step of determining the remaining quantity of biodegradable organic matter in the digestate, and the at least one operating parameter of the extraction-evaporation system may then be determined as a function of the value of the ratio determined in step (b) and this remaining quantity. This may also be implemented when the extraction-evaporation system is implemented on any liquid medium.

[0149] This two-phase digestion step can be carried out under mesophilic or thermophilic temperature conditions.

[0150] The hydraulic residence time and the solids residence time may be the same, for example 0.5 to 6 days in the fermenter and 6 to 100 days in the digester.

[0151] The digestate produced during the anaerobic biological treatment step can be sent directly to the bioelectrochemical treatment step or can be sent to a liquid-solid digestate separation step allowing the digestate to be separated into a solid fraction and a liquid fraction, such as for example a step of centrifugation or filtration. The liquid fraction of the digestate is then sent to the bioelectrochemical treatment stage.

[0152] In one embodiment, the digestate, or its liquid fraction, may in particular have a COD / Ammoniacal Nitrogen ratio of 0.25 to 10 gCOD / gN. In particular, this ratio may correspond to the ratio of the concentration of VFAs to the concentration of ammonium ions (VFA / Ammoniacal Nitrogen). The exact value of this ratio determined in step b) will generally vary depending on the desired NH4+ capture yield, the concentration of NH4+ ions in the digestate, as well as the ratio of NH4+ to the other cations in the digestate.

[0153] Alternatively or in combination, the digestate or its liquid fraction may have one or more of the following characteristics: - a total ammoniacal nitrogen concentration of 0.5 to 7gN / L or 0.5 to 5gN / L, or in any interval defined by two of these limits, - a conductivity of 10 to 150 mS / cm or 10 to 75 mS / cm or in any interval defined by two of these limits, - a molar ratio of the ammonium ion concentration to the total cation concentration (NH4+ / total cations) of 0.25 to 1 mol / mol or 0.75 to 1 mol / mol or in any interval defined by two of these limits.

[0154] The concentration of total ammoniacal nitrogen can be measured by colorimetric method, by acid-base dosage, or by ion chromatography.

[0155] Conductivity can be measured according to standard NF EN 27888-January 1994 or IS 7888:1985.

[0156] Such characteristics of the digestate or its liquid fraction can make it possible to improve the operation of the bioelectrochemical treatment system.

[0157] Extraction-evaporation step

[0158] This step involves extracting a portion of the contents of a liquid medium containing biodegradable organic matter, then subjecting it to evaporation to separate a volatile fraction and a concentrated fraction, and returning the concentrated fraction to the liquid medium, optionally to a first phase of a two-phase anaerobic digestion step. It can be implemented in the extraction-evaporation system previously described.

[0159] Typically, upon evaporation, some of the water and other volatile substances contained in the withdrawn portion of the liquid medium, such as, but not limited to, carbon dioxide, ammonia, volatile fatty acids, optionally low molecular weight fermentation compounds, hydrogen sulfide or other sulfur-reduced odorous compounds, are evaporated from the withdrawn portion, forming a volatile fraction 7, and reducing the volume of portion 6, forming a concentrated fraction 8. Concentrated fraction 8 optionally contains microorganisms and / or enzymes which are returned to the liquid medium.

[0160] Evaporation may be controlled as a function of evaporation temperature, evaporation pressure, frequency of extraction of the portion from the liquid medium and / or flow rate of portion extracted from the liquid medium.

[0161] The evaporation can be carried out at a temperature and pressure chosen to avoid damaging the microorganisms and / or enzymes possibly contained in the portion to be evaporated. A person skilled in the art knows how to choose a temperature and / or pressure which do not damage and / or degrade the microorganisms and / or enzymes depending on their nature.

[0162] The pressure is typically the operating pressure of the evaporator. It may be a negative pressure relative to the pressure inside the enclosure containing the liquid medium, with vacuum being a possibility of negative pressure. This pressure is generally lower than the pressure inside the enclosure containing the liquid medium.

[0163] When, at the operating pressure of the evaporator, its temperature is higher than the boiling point of the portion extracted from the enclosure containing the liquid medium (which generally corresponds to the boiling point of water), degassing occurs and the volatile fraction is vapor composed mainly of non-condensable substances and little or no vapor.

[0164] When, at the operating pressure of the evaporator, its temperature is equal to or lower than the boiling point of the portion extracted from the enclosure containing the liquid medium, evaporation occurs during which the volatile fraction is composed mainly of vapor and non-condensable elements. As the pressure is lower than in the previous case, the quantity of non-condensables extracted should be greater.

[0165] Typically, the evaporation temperature is as high as possible, but similar to, lower than, or higher than the temperature of the enclosure containing the liquid medium.

[0166] This extraction-evaporation step may further comprise one or more of the following steps: - a step of condensation of said volatile fraction to separate it into a condensable fraction and a non-condensable fraction sent to the bioelectrochemical treatment step, for example implemented in at least one condenser, - a treatment step with a liquid effluent, during which either the volatile fraction or the non-condensable fraction of this volatile fraction is treated with a liquid effluent in order to extract the biodegradable organic matter and capture it in the liquid effluent which is then sent to the bioelectrochemical treatment step, for example implemented in at least one treatment device.

[0167] Bioelectrochemical treatment step

[0168] This step is implemented in a bioelectrochemical treatment system, in particular of the type previously described with reference to the biological treatment installation.

[0169] In one embodiment, the bioelectrochemical treatment step may comprise the implementation of a reaction chosen from a reaction for reducing dioxygen or nitrate and a reaction for producing dihydrogen or organic molecules of interest chosen from organic acids, alcohols, methane. This may make it possible to improve the recovery of the digestate or its liquid fraction treated. In particular, when the molecule of interest is methane, the total quantity of methane produced during the implementation of the method according to the invention may be increased. Thus, in a preferred embodiment, the bioelectrochemical treatment step comprises a methane production step. The bioelectrochemical treatment system may thus operate as a microbial fuel cell or an electrolyzer.

[0170] Whatever the embodiment, the method according to the invention may further comprise at least one step of recovering the nitrogen contained in said effluent enriched in ammonium ions chosen from (i) a stripping step followed by a step of absorbing the nitrogen, (ii) a step of precipitating the ammonium ions in the form of struvite (NH4 MgPO4 • 6 H2O).

[0171] The stripping step can typically be carried out in at least one column in which the effluent circulates countercurrent to a gas which can be air, or in a column containing a membrane (membrane stripping). This stripping step makes it possible to shift the chemical equilibrium of the effluent towards the gas phase (NH3gas). The adsorption step can typically be carried out in at least one column in which the gas phase leaving the stripping step is brought into contact with an absorbent, for example a sulfuric acid solution. The succession of stripping and absorption makes it possible to concentrate the nitrogen, for example in the form of ammonium sulfate in the case of washing with sulfuric acid.

[0172] The step of precipitation of ammonium ions in the form of struvite can typically be carried out in a reactor in which a source of magnesium and / or phosphorus is generally added to the effluent, for example as described in the publication: Desmidt E, Ghyselbrecht K, Zhang Y, et al. Global phosphorus scarcity and full-scale p-recovery techniques: a review. Crit Rev Env Sci Technol. (2015).

Claims

Claims

1. Method for determining at least one operating parameter of an installation (100) for biological treatment of an input containing carbonaceous material and nitrogen compounds, the installation comprising: - an anaerobic biological system (110) producing biogas and digestate, - an extraction-evaporation system (160) adapted to extract a portion (6) of a liquid medium containing biodegradable organic matter and to separate it by evaporation into a volatile fraction (7) containing volatile organic matter and into a concentrated fraction (8) returned to the liquid medium, - a bioelectrochemical treatment system (120) receiving the digestate (3) or a liquid fraction (3a) thereof and said volatile fraction (7), this system comprising electroactive microorganisms and at least one separator (124) capable of allowing ammonium ions to pass when a potential difference is applied said method comprising: (a) a step of acquiring (ai) a value of at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions, and (aii) a value of at least one quality parameter of the digestate or its liquid fraction, representative of a quantity of ammonium ions relative to a total quantity of cations, (b) a step of determining a value of a ratio characteristic of the mixture of said volatile fraction with the digestate or its liquid fraction, representative of a quantity of biodegradable organic matter relative to a quantity of ammonium ions, this value being determined as a function of (bi) a target yield of ammonium ions extracted from the bioelectrochemical treatment system or a target concentration of separated ammonium ions present in the bioelectrochemical treatment system, and (bii) the values acquired in step (a), (c) a step of determining at least one operating parameter of the extraction-evaporation system as a function of the value of the ratio determined in step (b), the at least one operating parameter of the extraction-evaporation system being chosen from the evaporation temperature, evaporation pressure, frequency of extraction of the portion from the liquid medium, flow rate of portion extracted from the liquid medium.

2. Determination method according to claim 1, characterized in that the acquisition step (a) comprises one or more of the following characteristics: - the at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions is chosen from at least one parameter representative of the capacity of the at least one separator to allow the ammonium ions to pass, and a parameter representative of a concentration gradient of the cations on either side of the at least one separator, - the at least one parameter representative of the capacity of the electrochemical treatment system to separate ammonium ions is at least one parameter representative of the capacity of the at least one separator to allow ammonium ions to pass, and its value is estimated or determined from intrinsic characteristics of the separator, - the at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions is at least one parameter representative of a concentration gradient of the cations on either side of the at least one separator, and its value is estimated or calculated, - at least one quality parameter of the digestate or its liquid fraction is chosen from the ratio of its ammonium ion concentration to its conductivity or the ratio of its ammonium ion concentration to its total cation concentration, - the value of at least one quality parameter of the digestate or its liquid fraction is estimated or calculated based on the concentration of the digestate or its liquid fraction in ammonium ions, and its conductivity or its total concentration in cations.

3. A determination method according to any one of claims 1 or 2, characterized in that the determination step (b) comprises one or more of the following characteristics: - the characteristic ratio of the mixture is chosen from the C / N ratio of the quantity of carbon to the quantity of nitrogen, the COD / NH4+ ratio of the chemical oxygen demand to the concentration of ammonium ions, the AGV / NH4+ ratio of a concentration of volatile fatty acids to the concentration of ammonium ions, the DB05 / NH4+ ratio of the demand biological oxygen at 5 days on the concentration of ammonium ions, - the target yield of extracted ammonium ions or the target concentration of separated ammonium ions are determined based on a subsequent treatment of an effluent containing the ammonium ions extracted from the bioelectrochemical treatment system, this treatment being chosen from struvite precipitation and stripping.

4. A method according to any one of claims 1 to 3, characterized in that step (c) further comprises: - determining at least one operating parameter of the bioelectrochemical treatment system as a function of the value of the ratio determined in step (b), the value of at least one quality parameter of the digestate or its liquid fraction acquired in step (a), the at least one operating parameter of the bioelectrochemical treatment system being chosen from the residence time of the digestate or its liquid fraction in the bioelectrochemical treatment system, the flow rate of effluent enriched in ammonium ions extracted from the bioelectrochemical treatment system, a potential difference applied to the bioelectrochemical treatment system.

5. Method for biological treatment of an input containing carbonaceous material and nitrogen compounds to produce biogas and recover ammonium ions, by means of a biological treatment installation (100) comprising: - an anaerobic biological system (110) producing biogas and digestate, and - an extraction-evaporation system (160) adapted to extract a portion (6) of the contents of a liquid medium containing biodegradable organic matter and to separate it by evaporation into a volatile fraction (7) containing volatile organic matter and into a concentrated fraction (8) returned to the liquid medium, - a bioelectrochemical treatment system (120) receiving the digestate or a liquid fraction thereof and said volatile fraction, said bioelectrochemical treatment system comprising electroactive microorganisms and at least one separator (124) capable of allowing ammonium ions to pass upon application of a potential difference, said method comprising: - a step of determining at least one operating parameter of the extraction-evaporation system implementing the determination method according to any one of claims 1 to 4, - an anaerobic biological treatment step producing biogas and a digestate, - an extraction-evaporation step during which a portion of the contents of a liquid medium containing biodegradable organic matter is extracted and then subjected to evaporation to separate a volatile fraction and a concentrated fraction, and the concentrated fraction is returned to the liquid medium, this extraction-evaporation step being implemented using the at least one operating parameter of the extraction-evaporation system previously determined to separate a volatile fraction containing a determined quantity of biodegradable organic matter and obtain a mixture of the volatile fraction with the digestate or a liquid fraction of the digestate comprising biodegradable organic matter and ammonium ions according to the ratio value determined in step (b) of the determination method,- a bioelectrochemical treatment step during which electroactive microorganisms oxidize the biodegradable organic matter contained in the mixture of the volatile fraction with the digestate or its liquid fraction, at least part of the ammonium ions contained in the digestate or its liquid fraction migrates through the at least one separator and an effluent enriched in ammonium ions is extracted from the bioelectrochemical treatment system.,

6. Biological treatment method according to claim 5, characterized in that the bioelectrochemical treatment step further comprises the implementation of a reaction chosen from a reaction for reducing dioxygen or nitrate and a reaction for producing dihydrogen or organic molecules of interest chosen from organic acids, alcohols, methane.

7. Biological treatment method according to claim 5 or 6, characterized in that it further comprises at least one step of recovering the nitrogen contained in said effluent enriched in ammonium ions chosen from (i) a stripping step followed by a step of absorption of the nitrogen, (ii) a step of precipitation in the form of struvite of the ammonium ions.

8. Biological treatment method according to any one of claims 5 to 7, characterized in that:

9. - the determining step further determines at least one operating parameter of the bioelectrochemical treatment system, and - during the bioelectrochemical treatment step, the bioelectrochemical treatment system is implemented using at least one operating parameter of the bioelectrochemical treatment system determined during the determination step. System for determining (200) at least one operating parameter of a biological treatment installation for an input containing carbonaceous material and nitrogen compounds, the installation (100) comprising: - an anaerobic biological system (110) producing biogas and digestate, - an extraction-evaporation system (160) adapted to extract a portion (6) of the contents of a liquid medium containing biodegradable organic matter and to separate it by evaporation into a volatile fraction (7) containing volatile organic matter and into a concentrated fraction (8) returned to the liquid medium, - a bioelectrochemical treatment system (120) receiving the digestate or a liquid fraction thereof and said volatile fraction, said bioelectrochemical treatment system comprising electroactive microorganisms and at least one separator (124) capable of allowing ammonium ions to pass when a potential difference is applied, said system comprising: - means for acquiring (210) (ai) a value of at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions, and (aii) a value of at least one quality parameter of the digestate or its liquid fraction, representative of a quantity of ammonium ions relative to a total quantity of cations, - first determining means (220) adapted to determine a value of a characteristic ratio of the mixture of said volatile fraction with the digestate or its liquid fraction, representative of a quantity of biodegradable organic matter relative to a quantity of ammonium ions, as a function of (bi) a target yield of ammonium ions extracted from the bioelectrochemical treatment system or a target concentration of separated ammonium ions present in the bioelectrochemical treatment system, and (bii) the values received from the acquisition means, - second determination means (230) adapted to determine at least one operating parameter of the extraction-evaporation system as a function of the value of the ratio determined by the first determination means, the at least one operating parameter of the extraction-evaporation system being chosen from the evaporation temperature, the evaporation pressure, the frequency of extraction of the portion from the liquid medium, the flow rate of the portion extracted from the liquid medium.

10. Determination system (200) according to claim 9, characterized in that it comprises at least one of the following characteristics: - the acquisition means (210) are means for acquiring at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions chosen from at least one parameter representative of the capacity of the at least one separator to allow the ammonium ions to pass, and a parameter representative of a concentration gradient of the cations on either side of the at least one separator, - the acquisition means (210) are adapted to estimate or determine from intrinsic characteristics of the at least one separator the value of at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions which is at least one parameter representative of the capacity of the at least one separator to allow the ammonium ions to pass,- the acquisition means (210) are adapted to estimate or calculate the value of at least one parameter representative of the capacity of the electrochemical treatment system to separate the ammonium ions which is at least one parameter representative of a concentration gradient of the cations on either side of the at least one separator, - the acquisition means (210) are adapted to estimate or calculate the value of at least one quality parameter of the digestate or of its liquid fraction as a function of the concentration of the digestate or of its liquid fraction in ammonium ions, and of its conductivity or of its total concentration in cations, - the first determination means (220) are adapted to determine the target yield of extracted ammonium ions or the target concentration of separated ammonium ions as a function of a subsequent treatment of an effluent containing the extracted ammonium ions, of at least one recovery compartment, this treatment being chosen from struvite precipitation and stripping, - the first determining means (220) are adapted to determine a characteristic ratio of the mixture chosen from the C / N ratio of the quantity of carbon to the quantity of nitrogen, the COD / NH4+ ratio of the chemical oxygen demand to the concentration of ammonium ions, the AGV / NH4+ ratio of a concentration of volatile fatty acids to the concentration of ammonium ions, the DBO5 / NH4+ ratio of the biological oxygen demand at 5 days to the concentration of ammonium ions.

11. Determination system (200) according to claim 9 or 10, characterized in that the second determination means (230) are adapted to determine at least one operating parameter of the bioelectrochemical treatment system as a function of the value of the ratio determined in step (b), of the value of at least one quality parameter of the digestate or of its liquid fraction acquired in step (a), the at least one operating parameter of the bioelectrochemical treatment system being chosen from the residence time of the digestate or of its liquid fraction in the at least one anode compartment, the flow rate of effluent enriched in ammonium ions extracted from the bioelectrochemical treatment system, a potential difference applied to the bioelectrochemical treatment system.

12. Installation (100) for biological treatment of an input containing carbonaceous material and nitrogen compounds to produce biogas and recover ammonium ions, the installation comprising: - an anaerobic biological system (110) producing biogas (2) and digestate (3), - an extraction-evaporation system (160) adapted to extract a portion (6) of the contents of a liquid medium containing biodegradable organic matter and to separate it by evaporation into a volatile fraction (7) containing volatile organic matter and into a concentrated fraction (8) returned to the liquid medium, - a bioelectrochemical treatment system (120) receiving the digestate (3) or a liquid fraction (3a) thereof and said volatile fraction (7), this bioelectrochemical treatment system comprising electroactive microorganisms and at least one separator (124) capable of allowing ammonium ions to pass when a potential difference is applied, characterized in that it comprises: - a system for determining (200) at least one operating parameter according to any one of claims 9 to 11, - a regulation system (300) adapted to receive the at least one operating parameter from the determination system, and to modify the corresponding operating parameter of the extraction-evaporation system, and optionally of the bioelectrochemical treatment system, using the at least one operating parameter determined by the determination system.

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