BR102021013839A2 - AGROINDUSTRIAL EFFLUENT CONCENTRATION PROCESS BY REDUCING THE WATER CONTENT AND USE OF THE CONCENTRATE PRODUCT AND PROCESS BY-PRODUCTS - Google Patents

Abstract

The present invention provides a process for concentrating agro-industrial effluents, in particular vinasse. The process uses concentrated vinasse as a product, which tends to reduce the logistics of transporting this effluent, as well as reducing greenhouse gas emissions associated with agroindustry processes and activities. The electrolytic concentration of vinasse has hydrogen and oxygen gases as by-products. From the by-products obtained above, it is possible to provide a chain of use in order to add value to them. This chain of values includes the use of oxygen, a by-product of the electrolytic vinasse concentrator, to produce electrical energy from the oxy-flame type combustion of a fuel, additionally generating electrical energy from the condensation energy of the water contained in the Exhaust gas flow of oxy-flame combustion system generated by combustion of a fuel with oxygen gas, additionally providing separation of the content of exhaust gas stream from oxy-flame combustion, exemplary applicable for capture and storage of (CCS) or carbon capture and utilization (CCU), and additionally, the production of chemical inputs by the chemical reaction of hydrogen gas, a by-product of the vinasse electrolytic concentrator, with a current rich in carbon dioxide, for example, nitrogen gas .

Description

AGROINDUSTRIAL EFFLUENT CONCENTRATION PROCESS BY REDUCING THE WATER CONTENT AND USE OF THE CONCENTRATE PRODUCT AND PROCESS BY-PRODUCTS Field of Invention:

[001] The present invention is part of the field of chemistry and effluent treatment, and refers to a process for the treatment and concentration of agro-industrial wastewater, more specifically, it refers to a process for the concentration of agro-industrial effluents, preferably vinasse , by reducing the water content through electrolysis, and additionally using the by-products of the process as a value chain enabled by the electrolytic concentration of its agro-industrial effluents.

Fundamentals of the Invention:

[002] Agroindustrial processes, such as the production of biofuels, or more broadly those associated with fermentation, tend to generate large amounts of effluents, including, but not limited to, vinasse, which, for example, is a by-product of the producing industries of bioethanol and may have a high water content, generally greater than 95% (CORTES-RODRÍGUEZ et al., 2018). Vinasse can be used as fertilizer, for example, through fertigation processes, although this is related to economic and environmental problems.

[003] Like fertilizer, agro-industrial effluents such as vinasse can represent an economical and low-carbon alternative to commercial fertilizers (a term used interchangeably here with mineral fertilizers to refer to synthetic fertilizers). However, when applied to field crops as produced (i.e., in natura), vinasse can cause environmental problems and related economic constraints, including, but not limited to, greenhouse gas emissions and high transportation logistics costs. .

[004] It is known that the application of vinasse to the sugarcane plantation is responsible for promoting greater release of greenhouse gases, being related, although not limited to, burning of fossil fuels (e.g. diesel) by vehicles during the transport of these effluents and promotion of greater amounts of greenhouse gas emissions from the soil of the sugar cane plantation, (CARMO, et. al, 2012), (CHRISTOFOLETTI, et. al, 2013), (OLIVEIRA, et. al, 2013), (GALLO, et. al, 2019).

[005] The economic concern is related to the cost of transporting vinasse, which tends to become uneconomical versus mineral fertilizers, as the distance from the production source to the point of application becomes considerable (RABELO, et. al, 2015) , et. al, 2018). In addition, mineral fertilizers associate a greater carbon footprint with commodities sold by associated agricultural industries.

[006] On the other hand, reducing the amount of water in effluents can bring benefits associated with the aforementioned economic and environmental concerns. For example, the evaporative concentration of vinasse is one of the ways to carry out such a reduction thermally, however, it tends to involve high heat demands and investment costs (NAKASHIMA & OLIVEIRA JÚNIOR, 2020). These factors may have restricted the implementation of this evaporative process in the sugar and alcohol industry, for example.

[007] In addition, there is a global desire for systems and processes with zero emission of greenhouse gases, and even more for systems and processes with negative emission of greenhouse gases, where in agriculture these emissions can reach large scales. Furthermore, processes with negative greenhouse gas emissions potentially stimulate increased profitability of products sold by industries, such as green market trends.

[008] In view of the above and in order to solve the problems and limitations in the technical field in question, described above, the objective of the invention is to provide a way to treat and remove water from agro-industrial effluents, preferably, although not limited to vinasse, through electrolysis, and thus enable a chain of values from the use of by-products of this process, which overcome the economic aspects, concerns and environmental problems mentioned in this document.

[009] Hydrogen (H2) and oxygen (O2) gases generated in the effluent electrolytic concentration process, in particular vinasse, can become commodities for the agroindustry, or can be used as inputs in advanced combustion processes or combined with other molecules for the synthesis of synthetic chemical molecules or in biological processes, thus characterizing the invention as advantageous compared to technologies found in the state of the art related to the technical field in question.

State of the art

[010] In the state of the art, there are several documents that present vinasse treatment processes, however, the vast majority employing other techniques and conditions, and covering different solutions of the present invention.

[011] Document CN104371780B uses electricity from abandoned wind or solar sources to decompose organic matter, contained in industrial effluents, by electrolysis and the use of by-products to obtain synthetic natural gas through coal gasification. Document WO2016035288A1 refers to a process for producing electrolyzed functional water useful for plant growth. Document BR1120140194602 deals with an electrode and an electrochemical method for reducing the chemical demand for oxygen, that is, decomposition of organic matter from industrial effluents, in line with the document cited above.

[012] Corrêa's master's thesis (Corrêa, 2010), entitled "Production of Hydrogen from Vinasse", deals with a biological and an electrochemical method to reduce the chemical demand for oxygen and, consequently, the environmental impacts arising from the use of vinasse by the sugar and alcohol industries, as well as the production of hydrogen, through anaerobic digestion or electrolysis, for application as an alternative fuel.

[013] Document US20070062820 deals with a system for treating wastewater by electrolysis, where the objective is to generate oxygen necessary to promote the microbial decomposition of the organic matter contained in these effluents. In addition, this patent document proposes the use of the by-product of this electrolytic process, called hydrogen, to feed a fuel cell and thus reduce the overall energy consumption of the treatment process.

[014] Document KR101915261B1 deals with a method to produce energy for a wastewater treatment plant. In the process, water separated from the wastewater treatment process is used to generate hydrogen, which is used, together with CO2 from biogas combustion, to produce methane, which is used to feed the power generation system by burning of biogas and thus generate extra energy.

[015] Document PI0401563-0 deals with a process and equipment for treating vinasse. The process refers to the decomposition of the organic matter contained in the stillage by electrolysis. The equipment refers to an evaporation column for removing the water contained in the vinasse treated by electrolysis. The non-gaseous residue from the evaporation column is an organo-mineral fertilizer. Document US9512017B2 deals with a new electrolytic cell for treating effluents which promotes the reduction of the effluent's chemical demand for oxygen due to the decomposition of organic matter by electrolysis.

[016] As described above, there is no state-of-the-art document that deals with reducing the volume of agro-industrial effluents, particularly vinasse, by reducing the water fraction through electrolysis. Documents were found dealing with the concentration of vinasse by thermal means. Documents were also found that deal with the decomposition of organic matter contained in effluents through electrolysis. There are also documents that aim to reduce the chemical oxygen demand of vinasse, in one document, concomitantly producing hydrogen to be used as an alternative fuel. However, no precedent was found for the use of direct electric current, applied in a direct and controlled manner, for the electrolytic concentration of vinasse. Such a process has as by-products hydrogen and oxygen gases, which can serve as commodities and used as inputs in combustion processes of the oxy-flame type, or in the synthesis of synthetic chemical molecules, making the process, as a whole, economically viable and associated with a circular economy concept. Also, no such value chain was found in the state of the art, especially in the present context of sugar and alcohol plants.

Brief description of the invention

[017] The present invention provides a process for the concentration of agro-industrial effluents, in particular vinasse, by reducing the water fraction using electrochemical means, and obtaining a chain of values from the use of by-products of this concentration process . The process in question comprises a way to reach the concentration of agro-industrial effluents, in particular vinasse, comprising the steps of: (i) providing an electrochemical cell (for example, an electrolyser) comprising a cathode and an anode; (ii) provide an effluent flow in contact with the anode and the cathode; (iii) electrochemically decompose the water contained in the effluent; (iv) electrochemically produce hydrogen gas at the cathode, from water (or one of its dissociated ions) contained in the effluent; (v) electrochemically produce oxygen gas at the anode, from water (or one of its dissociated ions) contained in the effluent.

[018] From the products and by-products of the process, the present invention also highlights a chain of uses for adding value to the by-products of the electrolytic concentration of agro-industrial effluents, in particular vinasse, comprising, but not limited to, the following steps: ( i) use of oxygen gas, generated at the anode of the electrochemical cell from water (or one of its dissociated ions) contained in the effluent, together with a renewable fuel (e.g. sugarcane bagasse and biogas) or non-renewable (e.g. natural gas) and shale gas) for the production of electricity in an oxy-flame type combustion system; (ii) destination of the exhaust gas from the oxy-flame combustion system, generated by the combustion between a fuel and oxygen gas from the electrolytic concentration of the effluent, for carbon capture and storage (CCS) or capture and use of carbon (CCU), after condensation of the water present in the exhaust gas; (iii) use of the exhaust gas flow from the oxy-flame combustion system, generated by the combustion between a fuel and oxygen gas from the electrolytic concentration of the effluent, for the generation of electricity through the extraction of condensation energy from water present in the exhaust gas; (iv) use of hydrogen gas, generated at the cathode of the electrochemical cell from water (or one of its dissociated ions) contained in the effluent, together with other inputs (for example nitrogen gas from the air or carbon dioxide generated by the system oxy-flame combustion) for the production of chemical inputs in a chemical or electrochemical reactor, such as, for example, the synthesis of ammonia through the Haber-Bosch process or the synthesis of urea through the Bosch-Meiser process; (v) use of the concentrated effluent, through electrolysis of the water (or its dissociated ions) contained in the effluent, for the production of biogas in a biodigester.

Brief description of figures

[019] In FIGURE 1 is shown the representative flowchart of the process of electrolytic concentration of vinasse, highlighting each of the steps of the process.

[020] FIGURE 2 shows a schematic drawing of the vinasse electrolytic concentrator, used in the electrolysis step. Vinasse as input and concentrated vinasse as output and product of the process.

[021] FIGURE 3 shows a type of schematic diagram of the use of an effluent, in particular vinasse, and various energy sources to produce chemical inputs, and their use in various exemplary ways: electrolytic concentration of vinasse, sources of electric energy, concentrated vinasse and the by-products produced hydrogen and oxygen gases, respectively, as a product and by-products of the process and exemplary ways of using such product and by-products, conferring several advantages to the process.

Detailed description of the invention:

[022] The present invention relates to a process of treating and concentrating an agroindustrial effluent, specifically vinasse, by reducing its water concentration through electrolysis, producing concentrated vinasse as a product and hydrogen and oxygen gases as by-products. "Concentrated vinasse" refers to vinasse containing post-electrolysis water concentration lower than that of pre-electrolysis, observing variations in the physicochemical properties of pre-electrolysis vinasse.

[023] As shown in FIGURE 1, the invention comprises the following steps: (a) supply a stream of vinasse, from the fermentation of sugarcane, to the electrolyser; (b) carry out pre-treatment of the vinasse stream, if necessary; (c) carry out electrolysis of the water present in the stillage; (d) recirculate the concentrated stillage for new electrolysis, if necessary; (e) remove the concentrated vinasse from the electrolyser and collect the gaseous by-products, ie hydrogen and oxygen gases, whether or not they undergo a separation process. If there is pre-treatment, it may include, but is not limited to, the following sub-steps: sedimentation, flotation, filtration, pH correction.

[024] According to FIGURE 1 and FIGURE 2, with regard to the applicability of the invention, the following steps can be defined for a vinasse treatment: (i) provide an electrolytic vat (that is, a container capable of to contain a predetermined volume of vinasse, according to FIGURE 2); (ii) provide two electrodes (ie, a cathode and an anode) connected through an external electrical circuit; (iii) supply a volume of vinasse to the vat, whether pre-treated or not, so as to close the electrical circuit; (iv) supplying a continuous electric current to the cell electrodes; (v) concentrate the vinasse, through the electrolytic decomposition of the water contained therein, having concentrated vinasse as a product; (vi) produce, as a by-product of the vinasse electrolytic concentration process, hydrogen gas at the cathode and oxygen gas at the anode, from the water (or one of its dissociated ions) contained in the vinasse; (vii) direct the concentrated vinasse out of the electrolytic vat; (viii) collect the gaseous by-products, ie hydrogen and oxygen gases, whether or not they undergo a separation process.

[025] The recirculation step may include the use of electrolysers in series or the recirculation of concentrated vinasse in the electrolyser. Gases from electrolysis, specifically hydrogen and oxygen gases, are collected and may or may not go through a separation process. The physicochemical properties of vinasse are not exactly defined. Being a product of biological activities, its composition and temperature in the electrolyser input stream are variable.

[026] For the purpose of the electrolysis process in the electrolytic vinasse concentrator, the cathode catalyst and the anode catalyst may be a metallic catalyst or a non-metallic catalyst or a combination thereof. The electrolyte is the agro-industrial effluent, being in contact with the anodic and cathodic electrodes. The electrolyser may or may not contain a membrane (i.e., a selective semipermeable ion exchange material and electrical insulator) or a mesh (i.e., a permeable electrical insulator and non-ion conductor), in this case, the effluent, in particular the vinasse , acts as an electrolyte for the anode and cathode.

[027] A membrane or a mesh can be employed between the anode and cathode to separate these electrodes, allowing ions to flow, while avoiding a harmful electrical short circuit. It should be noted that the anode and cathode are spaced apart to prevent an electrical short circuit when a membrane or mesh is not present. The membrane and the mesh are insoluble in the effluent and the flow of hydrogen gas, a by-product generated in the effluent electrolytic concentration process, particularly vinasse, may or may not undergo separation or purification processes. It will be noted that the flow of oxygen gas, a by-product generated in the effluent electrolytic concentration process, particularly vinasse, may or may not undergo separation or purification processes.

[028] When the electrolyser of the vinasse electrolytic concentrator comprises a mesh or a membrane, the cathode may be in a cathode compartment and the anode may be in an anode compartment, and the mesh or membrane separates the cathode compartment from the anode compartment . When present, a mesh does not act to selectively transport ions, although it can prevent electrical contact between the cathode and anode while minimizing their separation to help minimize the ionic resistance of the electrolyser. It will be noted that a mesh allows the electrolyte (vinasse) to pass between the cathode and anode compartments. The mesh can be made of an organic material, such as a polymeric material, or an inorganic material, such as a ceramic material, or a combination thereof.

[029] When the electrolyser of the vinasse electrolytic concentrator comprises a membrane, the cathode will be in a cathode compartment and the anode will be in an anode compartment, with the membrane separating the cathode compartment from the anode compartment. Where the electrolyser comprises a membrane, the electrolyte may be different for each compartment, with the membrane acting to mediate the exchange of relevant ions between the compartments. It will be appreciated that a membrane can be made of an organic or an inorganic material, or a combination of both.

[030] Exposure of the effluent to the electrolyser of the vinasse electrolytic concentrator reduces the concentration of water in the effluent stream, thus, the water contained in the effluent flow, in particular the vinasse, can be directly electrochemically converted to oxygen gas at the anode and hydrogen gas at the cathode. By "direct electrochemical conversion" is meant that water is converted into oxygen gas at the anodic surface and into hydrogen gas at the cathode surface, without the involvement of other chemical reagents. The same applies to the cathode. The electrochemical reactions described here do not involve radical species.

[031] When water (solvent), or its dissociated ions, contained in the effluent flow, in particular vinasse, is electrochemically converted at the anode and cathode, the anode and cathode additionally comprise a catalyst, which may have the same material composition or not. Therefore, the cathode and anode may comprise a catalyst (hereinafter referred to as cathode catalyst and anode catalyst, respectively, such as nanoparticulate Pt dispersed on a high surface area conductive matrix), which is capable of catalyzing reduction and oxidation reactions, respectively.

[032] Ο cathode catalyst may or may not be supported by organic or inorganic materials or a combination thereof. The cathode catalyst can be an organic or inorganic material or a combination thereof. The anodic catalyst may or may not be supported by organic or inorganic materials, or a combination thereof. When a membrane or a mesh is used in the electrolyser of the vinasse electrolytic concentrator, a semipermeable layer may or may not be present on the anode and cathode electrode, to prevent ions other than water dissociated ions from reaching the catalyst and the membrane.

[033] The process of the present invention can be carried out at low temperatures, without external heating being provided. However, the effluent stream may comprise residual heat, that is, the effluent stream may be supplied to the electrolyser of the vinasse electrolytic concentrator at temperatures that exceed the ambient temperature around the electrolyser. Thus, the process of the present invention can be carried out at temperatures from about 15°C to close to the boiling point of water present in the effluent.

[034] The boiling point of water in the effluent, and therefore the upper limit of the temperature at which electrolysis can operate, is a function of the ambient pressure and the composition of the effluent. Water boils at about 373 K (~100°C or ~212°F) at ambient pressure of 1 atm and correlates positively with ambient pressure. The dependence of boiling temperature on wastewater composition is a colligative property of the solution and, in general, is positively correlated with solute concentration. Effluents may or may not show azeotropic behavior in their phase diagram (temperature versus composition).

[035] The pH of the effluent may vary. For example, when considering effluent from fermentation-based processes, in particular vinasse, the pH of the effluent entering the electrolyser may be in the range of about 3 to about 6. The effluent stream may or may not be used in the electrolyser without modification. When modified, one or more additives can be added to the effluent stream before entering the electrolyser of the vinasse electrolytic concentrator. Examples of such additives include a base, such as sodium hydroxide, or an acid, such as phosphoric acid, or a salt, such as sodium bicarbonate, or a combination thereof. One or more additives can promote the efficiency of the electrolytic concentration of vinasse and the productivity of plantations, when the concentrated effluent, which leaves the electrolytic concentrator of vinasse, is applied as fertilizer.

[036] The concentrated vinasse before or after the incineration process promotes reductions in greenhouse gas emissions and costs associated with agroindustry processes, for example, minimizing transport logistics. The efficiency of the electrolysis process, of the vinasse electrolytic concentrator, in general, correlates with the acidity or alkalinity of the wastewater. For example, in the case of catalysts that are optimal in an acid medium, that is, pH < 7, the lower the pH, the higher the concentration of H+ ions and, therefore, the higher the reaction rate and the lower the overpotential (greater energy efficiency of the electrolysis process). Something analogous occurs for alkaline media, pH > 7, with the distinction that the evolution of oxygen gas will be more efficient the higher the pH. In general, the closer to pH = 7, the lower the efficiency of the process, with the exception of situations that use catalysts suitable for neutral media.

[037] It will be appreciated that, during the process, a single electrolyser may be used or a plurality of electrolysers, where such a plurality of electrolysers may be connected in series or in parallel to each other. It will also be appreciated that the electrolyte can be recirculated to, for example, but not limited to, minimize the use of additives.

[038] As shown in FIGURE 3, for the purpose of the value chain for the by-products of the process, the uses that compose it are based on the availability of the product of the electrolytic vinasse concentrator (concentrated vinasse), the by-products of the concentration process electrolysis of vinasse (hydrogen and oxygen gases), secondary products from processes proposed for the value chain (e.g. electrical energy), as well as by-products of secondary processes (carbon dioxide and condensation water). In this way, the value chain of the present invention deals with examples of possible uses for these by-products, adding several advantages to the process.

[039] Therefore, the present invention also refers to ways of using the product and by-products, generated by the process of electrolytic concentration of effluent, in particular vinasse, by the same industry as inputs or commodities. As an input, the concentrated vinasse product can be used as a fertilizer, before or after the incineration process, with reduced logistics costs compared to non-concentrated vinasse, and with a consequent reduction in greenhouse gas emissions.

[040] As a commodity, hydrogen gas can be sold directly as commodities (for example, oil refining and cracking, metal refining and heat generation) or it can be mixed with fuels produced or not in the same industry, for example, biogas and ethanol, promoting the flammability of the fuel and reducing the emission of greenhouse gases generated in the combustion of these fuels, where, in the case of biogas, this mixture could also minimize or eliminate the need for separation processes related to the removal of diluting molecules fuel, such as carbon dioxide.

[041] The oxygen gas by-product can also be sold directly as commodities or can be used in the oxy-flame type combustion of renewable fuels (for example, solid waste, semi-solids, substances from the same industry) or non-renewable fuels (for example, shale gas, natural gas) for the production of electricity. The exhaust stream from oxy-flame combustion can be routed before or after separation or purification processes to carbon capture and storage or carbon capture and utilization processes.

[042] When carbon capture and storage is considered, the exhaust flow from the oxy-flame combustion that has or has not gone through separation or purification processes can be directed to geological sites or be absorbed by suitable absorbents. When carbon capture and utilization is considered, the exhaust stream from the oxy-flame combustion that has or has not gone through separation or purification processes can be directed to systems to convert the molecule or molecules contained in that stream into other molecules or carbon molecules. interest in chemical transformations, this may or may not use hydrogen gas or oxygen gas.

[043] Examples of products of interest include, but are not limited to, fertilizers (e.g., ammonia and urea), chemical inputs, "dense energy carriers" (e.g., ammonia and methanol), as well as synthetic fuels and hydrocarbons in for the agro-industry itself or other industries. Hydrogen gas or oxygen gas, by-products of the vinasse electrolytic concentrator, may find additional applications to those already mentioned or not in this document, for example, although not limited to, biomass recovery, food processing, oil recovery and refining, production and manufacture of metals, methanol production, electronics, cosmetics, waste incineration (concentrated vinasse), as fuel, for energy storage, in engines and turbines for the agro-industry itself or other industries. In addition to being able to be used as chemical reagents together with other molecules, for example, in the production of commodities and chemical inputs for the agroindustry itself or other industries.

[044] The concentrated effluent, product of the electrolytic vinasse concentrator, can be used for the production of biogas in biodigesters. The concentrated vinasse, a product of the electrolytic vinasse concentrator, can be used as fertilizer directly or after the biogas production process. It will also be noted that the concentrated vinasse, a product of the electrolytic vinasse concentrator, or the residue from the biogas production process, whether undergoing biological activity or not, can be incinerated with oxygen gas, a by-product of the electrolytic vinasse concentrator, and then be used as fertilizer.

REFERENCES

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[046] Christofoletti, C. A., J. P. Escher, J. E. Correia, J. E. U. Marinho and C. S. Fontanetti (2013). "Sugarcane vinasse: Environmental implications of its use." Waste Management 33(12): 2752-2761.

[047] Cortes-Rodriguez, E. E., N. A. Fukushima, R. Palacios-Bereche, A. V. Ensinas and S. A. Nebra (2018). "Vinasse concentration and juice evaporation system integrated to the conventional ethanol production process from sugarcane - Heat integration and impacts in cogeneration system." Renewable Energy 115: 474-488.

[048] da Silva Neto, J. V., W. L. R. Gallo and E. A. A. Nour (2020). "Production and use of biogas from vinasse: Implications for the energy balance and GHG emissions of sugar cane ethanol in the Brazilian context." Environmental Progress & Sustainable Energy 39(1): 13226.

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Claims (18)

Process for the concentration of agro-industrial effluents, in particular vinasse, characterized by comprising the steps of:

• (a) supplying an agro-industrial effluent stream to the electrolyser;
• (b) optionally perform pre-treatment of the agro-industrial effluent stream;
• (c) performing electrolysis of the water present in the vinasse, which comprises (i) providing an electrochemical cell comprising a cathode and an anode, (ii) providing an effluent flow in contact with the anode and cathode connected through a circuit external electrical, (iii) electrochemically decompose the water contained in the effluent by means of a continuous electric current, (iv) electrochemically produce hydrogen gas at the cathode, from the water, or one of its dissociated ions, contained in the effluent, (v ) Electrochemically produce oxygen gas at the anode, from water, or one of its dissociated ions, contained in the effluent;
• (d) optionally recirculating the concentrated agro-industrial effluent for new electrolysis; It is
• (e) remove the concentrated agro-industrial effluent from the electrolyser and collect the hydrogen and oxygen gas by-products, whether or not they undergo a separation process.

Process, according to claim 1, characterized by the fact that the pre-treatment of the agro-industrial effluent comprises preferably sedimentation, flotation, filtration and pH correction. Process, according to claim 1, characterized in that step (c) involves the direct and electrochemical production of hydrogen gas at the cathode, and in which the cathode comprises a cathode catalyst, preferably a cathode catalyst of organic or inorganic material or a combination thereof. Process, according to claim 3, characterized by the fact that the cathode catalyst is supported or not on organic or inorganic materials, or a combination thereof. Process, according to claim 1, characterized in that step (c) involves the direct and electrochemical production of oxygen gas at the anode, and in which the anode comprises an anode catalyst, preferably an anode catalyst of organic or inorganic material or a combination thereof. Process, according to claim 5, characterized by the fact that the anodic catalyst is supported or not on organic or inorganic materials or a combination thereof. Process, according to any one of the preceding claims, characterized in that it is conducted at a temperature between 15°C and even close to the boiling temperature of the effluents within the system. Process, according to any one of the preceding claims, characterized in that the solvent is preferably water. Process according to any one of the preceding claims, characterized in that the effluent additionally comprises a compound, a base or an acid or a salt or a combination thereof. Process according to any one of the preceding claims, characterized in that step (d) optionally includes the use of electrolysers in series. Process, according to any one of the preceding claims, characterized in that the electrolyser optionally contains a membrane or a mesh for the passage of ions. Process, according to any one of the preceding claims, characterized in that the pH of the effluent entering the electrolyser is in the range of 3 to 6. Process according to any one of the preceding claims, characterized in that one or more additives are optionally added to the effluent stream before entering the electrolyser. Use of hydrogen gas, a byproduct generated at the cathode of the electrochemical cell of the process as defined in claims 1 to 13, characterized by being in the production of chemical inputs in a chemical or electrochemical reactor. Use of oxygen gas, a by-product generated at the anode of the electrochemical cell in the process as defined in claims 1 to 13, characterized by being in the production of electricity in an oxy-flame type combustion system. Use, according to claim 15, characterized by the fact that the exhaust gas from the oxy-flame combustion system is intended for capturing and storing carbon or capturing and using carbon after condensation of the water present in the exhaust gas. Use, according to claims 15 or 16, characterized in that the exhaust gas from the oxy-flame combustion system is optionally used for the generation of electrical energy by extracting the condensation energy from the water present in the exhaust gas . Use of the concentrated product of the process, as defined in claims 1 to 13, characterized by being in the production of biogas in a biodigester.

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