Bioelectrochemical wastewater treatment system, electrode assembly, and bioelectrochemical wastewater treatment method

Abstract

An improved bioelectrochemical wastewater treatment method and system (1) is disclosed. The electrode assembly (4) is characterized by a series of interconnectable electrode modules (5). Each electrode module (5) includes a first electrode consisting of an anode and cathode pair coated with electrogenic microorganisms adapted to generate electrons through the consumption of organic matter in the wastewater. The electrode module (5) includes a second electrode consisting of an anode and cathode pair and a body that supports and separates the first and second electrodes. The electrode module (5) also includes an interface for physically connecting to at least one other electrode module.

Description

[Technical Field]

[0001] The present invention relates to improved systems and methods for the treatment of wastewater or organic waste and the generation of electricity and / or fuel, and in particular to the application of bioelectrochemical systems (BES) such as microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) for use in such systems and methods. [Background technology]

[0002] Bioelectrochemical systems (BES) are increasingly finding application in wastewater treatment. These systems generally contain electrodes coated with specific microorganisms that can purify wastewater, for example, through the oxidation of organic compounds to carbon dioxide. Furthermore, these systems and processes can produce useful by-products, including electricity, gaseous fuels such as methane and hydrogen, fertilizer, solid fuels such as biochar or charcoal, bioplastics, and other valuable products. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 012647 Summary of the Invention [Problem to be solved by the invention]

[0004] The exact function and effectiveness of a BES varies depending on the system's configuration. Generally, an anode is placed in a chamber into which the wastewater to be purified is introduced. The anode is coated with exoelectrogenic bacteria that produce electrons, carbon dioxide, and protons (i.e., hydrogen ions) as organic matter is broken down. The electrons are conducted directly to the anode, while the protons remain in aqueous solution.

[0005] In a microbial fuel cell (MFC) configuration, for example, oxygen and hydrogen ions are reduced at the cathode to produce water, and electricity is generated by a circuit between the anode and cathode. In an anaerobic microbial electrochemical cell (MEC) configuration, an external power source connected between the electrodes drives hydrogen production at the cathode while increasing the oxidation level of organic matter at the anode. Alternatively, certain methanogenic microorganisms may be used to generate methane.

[0006] Such systems are becoming increasingly popular for their application within municipal wastewater treatment plants and for the treatment of waste in chemical or food processing industries. These applications tend to be implemented through the connection of existing plant infrastructure to large-scale, purpose-built bioelectrochemical systems designed for the specific needs of the plant. For example, input parameters such as wastewater flow rate, its moisture content, organic loading rate, and chemical oxygen demand need to be optimally balanced with outputs such as treated water purity, biogas volume, and electrical energy.

[0007] Therefore, existing BES architectures tend to focus on specific wastewater treatment applications and are not adequate to accommodate a wide range of different applications where input and output parameters vary widely. Therefore, it is impractical to deploy many BES architectures on smaller scales, in remote locations, and / or to retrofit BES functionality into existing waste treatment infrastructure.

[0008] It is against this background that the present invention was made. [Means for solving the problem]

[0009] According to a first aspect of the present invention, there is provided a bioelectrochemical wastewater treatment system as set forth in claim 1.

[0010] The system includes a wastewater treatment tank, an electrode assembly, and at least one of an external power source or a load, and circuitry may be provided for connecting the external power source or the load to the electrode assembly.

[0011] The tank ideally consists of a wastewater intake and a treated water outlet. In some embodiments, the tank may be any suitable vessel or container for holding the wastewater to be treated. For example, the tank may take the form of a bag in an anaerobic bag digester. In some embodiments, the tank may extend to a reservoir or specially constructed wetland, with wastewater entering the tank via an upstream source and treated water flowing from a downstream source. However, it is preferred that the tank be a sealed container with a specific wastewater intake, treated water outlet, and ideally, a gas port that can harvest and utilize gases produced via the bioelectrochemical process. Of course, there may be multiple intakes, outlets, and gas ports. Furthermore, the tank may be divided into a sequence of adjacent chambers, thereby forcing the wastewater to follow a nonlinear path between the intake and outlet, which may advantageously increase the treatment period and increase contact between the wastewater and the electrode assembly.

[0012] Preferably, in use, the electrode assembly is submerged in the wastewater treatment tank between the intake and the discharge. Preferably, the electrode assembly includes a set of electrode modules, which are interconnectable. Ideally, one or more of the set of electrode modules includes a first electrode and a second electrode comprising an anode-cathode pair. The first electrode, ideally the anode of the anode-cathode pair, can be provided with a biocoating of electrogenic microorganisms adapted to generate electrons through the consumption of organic matter in the wastewater. The coating can include electromethanogenic microorganisms, thereby producing both electricity and methane through the consumption of organic matter in the wastewater. The coating can also include hydrogenotrophic microorganisms capable of producing biogas through the conversion of organic matter, hydrogen, and / or carbon dioxide. Each coating can use a heterogeneous set of microorganisms. Examples of microorganisms for this purpose include bacteria of the genera Geobacter and Shewanella.

[0013] In some embodiments, the second electrode, ideally comprising an anode-cathode pair, does not necessarily have to be coated with microorganisms, while in other embodiments, at least a portion of the second electrode may have a similar coating.

[0014] Ideally, the body of the electrode module supports the first and second electrodes and physically and electrically separates them.

[0015] To facilitate modularity, the electrode modules include interfaces that can be connected to one another. Furthermore, the interfaces may be configured to physically connect the electrode module to at least one other electrode module. Preferably, the interfaces are configured and arranged to physically connect the electrode module to at least two other electrode modules, thereby enabling a chain of electrode modules to be defined. Additionally, the interfaces are further arranged to electrically connect the electrodes of the interconnected electrode modules. In particular, the interfaces facilitate connection between the first and second electrodes of one electrode module and the first and second electrodes of each of the other connected electrode modules. Thus, in a set of electrode modules, all of the first electrodes are electrically connected to one another, and, independently of this, all of the second electrodes are electrically connected to one another.

[0016] Preferably, the system also includes a circuit that electrically connects the electrodes of the set of electrode modules to a power source or an electrical load. The system may be configured to control switching between the power source or the load depending on the configuration of the bioelectrochemical system thus defined. Typically, when the system operates in a microbial fuel cell (MFC) configuration, for example, the circuit electrically connects the electrodes of the set of electrode modules to the electrical load. When the system operates in a microbial electrolysis cell (MEC) configuration, for example, the circuit electrically connects the electrodes of the set of electrode modules to the power source. The power source may include a solar panel. The electrical load may include another system according to one aspect of the present invention. Thus, the circuits of different systems may be interconnected, for example, with the MFC supplying power to the MEC.

[0017] The modularity of the resulting system is particularly advantageous and overcomes, at least in part, the shortcomings of existing systems described in the preamble. For example, an electrode assembly can be composed of a set of electrode modules, so that its size, shape, and capacity can be adapted to a variety of different profiles of wastewater treatment tanks. The rate of BOD reduction, biogas and / or electricity generation can be modified by connecting a greater or lesser number of modules together, as appropriate.

[0018] It should be noted that the electrode modules are preferably in a membrane-less configuration, eg, without a proton exchange membrane between them.

[0019] Preferably, at least one of the first electrode and the second electrode (ideally the anode) is a brush electrode. At least one of the first electrode and the second electrode (ideally the cathode) is a pocket electrode. The electrode module may comprise a set of electrode holders. Each holder may include a complementary interface that allows connection between at least two holders. The complementary interface may include at least one of a sliding interface and a snap-fit interface.

[0020] Preferably, each electrode is elongate so as to define a longitudinal axis. Preferably, the first electrode and second electrode are carried by the body such that their respective longitudinal axes are substantially parallel to each other.

[0021] Preferably, each electrode module further comprises a plurality of holders at least partially defining a body for supporting and separating the electrodes.

[0022] At least one pair of holders can be spaced apart from one another by at least one elongated post and fixed relatively to one another to define an elongated framework within which each electrode is held such that the longitudinal axes of the elongated frameworks are substantially parallel to one another.

[0023] Preferably, each holder defines a plurality of spaced apart connection regions for releasably holding each electrode, and the connection regions of each holder may include a plurality of slots capable of enclosing the mounting portions of the respective electrodes to prevent relative movement of the electrodes.

[0024] Preferably, the mounting portion of the electrode is capable of moving in and out of the respective slot during engagement or removal of the electrode.The mounting portion of the electrode is preferably electrically conductive.

[0025] At least one of the plurality of holders may include a pair of conductor tracks, each of which may be arranged to hold a conductor for electrical connection to a respective electrode. Specifically, the first track may operate via the first electrode, and the second track may operate via the second electrode.

[0026] At least one of the holders can include clamping portions having a clamping configuration in which the clamping portions are compressed toward each other to capture the electrodes in place. In their clamping configuration, the clamping portions can compress the first and second conductors against the respective first and second electrodes. The conductors can span multiple electrode modules.

[0027] The holder and the conductor can at least partially define an interface for physically and electrically connecting the electrode module with at least one other electrode module of the set. The electrode assembly can include a junction box. The interface can include a junction box.

[0028] The electrode assembly may include a shell for isolating the electrode assembly from other electrode assemblies. The electrode assembly may include a resilient rod. The rod may be wrapped around the electrode module of the electrode assembly. Thus, the shell is ideally a primarily open structure, allowing waste to flow freely through and across the electrodes.

[0029] As noted above, the systems of the present invention can be applied to anaerobic bag fermentors and therefore used to enhance their operation, particularly for biogas generation. The electrode assemblies described above can be incorporated into anaerobic digesters, among other reactors, and numerous other waste treatment reactors to enhance their operation.

[0030] Preferably, the interface of one electrode module comprises a coupling member for coupling with a complementary coupling member of another electrode module. One coupling member may be a plug and the other may be, for example, a socket. Ideally, the interface of each electrode module of the set includes a coupling member such as a plug or socket for coupling with a complementary coupling member such as a socket or plug of another electrode module of the set.

[0031] Ideally, the complementary coupling members are shaped and arranged for a push-fit or snap-fit connection, and the interface may include a latch to prevent uncoupling of the connected complementary coupling members.

[0032] The body of each electrode module may be elongate and thus define a first end and a second end. Ideally, the interface of each electrode module includes first and second complementary coupling members disposed towards the respective first and second ends of the body. Advantageously, this allows a series of elongate electrode modules to be connected to one another.

[0033] Preferably, the system comprises a buoy. Preferably, the buoy is arranged to float in the wastewater treatment tank in use. Ideally, the buoy includes a connector constructed and arranged to connect with an interface of the electrode module. Thus, in use, a set of electrode modules are suspended from the buoy and submerged in the wastewater to be treated. In certain embodiments, the buoy's connector is further coupled to a power source or circuit leading to a load. Advantageously, this allows for easy assembly of the system, as only a single connection is required.

[0034] Preferably, the system includes a weight. Ideally, the weight includes a connector constructed and arranged to connect with an interface of the electrode module. When both the buoy and weight are used together, this pulls the interconnected set of electrode modules (buoy on top, weight on bottom) into a vertical position between the buoy and weight.

[0035] Advantageously, the buoy / weight placement ensures that the electrodes remain submerged within the wastewater treatment tank, which is important if the tank contains a gas headspace. If the microorganisms coated on the electrodes enter the headspace, they cannot consume the organic matter in the wastewater, thereby preventing effective treatment of the wastewater. Furthermore, the microbial population cannot thrive without an organic food source and will decline over time.

[0036] The electrode assembly preferably includes at least two sets of interconnectable electrode modules. Additionally, the buoy may include at least two corresponding connectors for connecting with each set of electrode modules. The at least two connectors may be positioned and spaced apart from one another to isolate each set of electrode modules from one another during use. The system may include a separation strut for this purpose, or alternatively, the at least two connectors may simply be positioned on the buoy at differently spaced locations.

[0037] It should be noted that the buoy can be made from one or more buoyant elements. For example, the buoy can be a matrix of buoyant elements (e.g., ball floats) interconnected and separated by separating struts. Alternatively, the buoy can be constructed from a single unit comprising a low-density material. The buoy can, for example, comprise one or more inflatable bladders.

[0038] Advantageously, if the buoy is inflatable, even at least partially, this allows the buoy to occupy a smaller volume during transport than when in use within the wastewater treatment tank.

[0039] The system may also include one or more weights. Ideally, there should be one for each set of electrode modules. In some embodiments, the weights may be interconnected and separated from one another by supports. This preferably coincides with the separation at the top of the electrode sets, so that each electrode set is ideally suspended between the weight and the buoy in a vertical and parallel orientation. This allows for optimal distribution of wastewater treatment sites across the tank and prevents shorting of electrodes.

[0040] As noted above, in certain embodiments of the present invention, the tank may take other forms and is not necessarily sealed for the purposes of the present invention. The wastewater treatment tank may, for example, be open at its top. In this example, the system preferably further includes a gas trap configured and arranged to capture gases emitted by the electrode assembly, particularly from the electrodes of the anode-cathode pair defined by one or more electrode modules. The gas trap is ideally configured to attach to the electrode assembly above the electrode modules to capture gases such as methane and / or hydrogen. Advantageously, this allows flexibility in the selection of the wastewater tank; i.e., it does not necessarily need to include a gas port.

[0041] Particularly contemplated is the deployment of certain aspects of the system in outdoor environments, such as wetland environments. In such embodiments, the gas trap and / or buoy typically float on the surface of the wastewater being treated. Additionally, they can support other components of the system, such as an external power source or load. For example, they can support solar panels and connect them to the electrode module. A further advantage is the ability to contact or circulate water across the back of the solar panels, which has the benefit of cooling them and thereby increasing their performance. This also typically increases the temperature of the reaction sites adjacent to the system's electrodes, again improving reaction efficiency and, therefore, the efficiency of decomposition of organic matter in the wastewater.

[0042] The body of each electrode module is ideally constructed from a flexible material, which advantageously allows the electrode module to be rolled up and easily transported to remote locations, and which is ideally porous to allow for the passage of wastewater.

[0043] Preferably, the electrode assembly includes multiple electrode modules positioned between the water intake and the outlet with varying spacing between the anode-cathode pairs defined by the electrode modules. This spacing may vary depending on the location of the anode-cathode pairs between the water intake and the outlet. For example, the spacing between the anode-cathode pairs defined by the electrode modules is ideally wider closer to the water intake and narrower closer to the outlet. Advantageously, the higher the organic matter density, the more likely the water intake will become clogged. Thus, providing wider spacing near the water intake can offset this risk. As the wastewater moves through the tank toward the outlet, the organic matter density decreases. Therefore, it is advantageous to decrease the spacing between the anode-cathode pairs defined by the electrode modules to proportionally increase treatment effectiveness. Ultimately, it is beneficial for the spacing to be narrowest closest to the water intake and closest to the outlet.

[0044] To facilitate retrofitting of electrode assemblies into vessels such as anaerobic bag fermenters, aspects of the present invention may allow the electrode assembly to be switched between an unexpanded and an expanded configuration. In the unexpanded configuration, the electrode assembly occupies a small volume and can therefore be easily inserted into such vessels. The electrode assembly can then be switched to the expanded configuration to increase its volume and thereby maximize the effectiveness of the electrodes.

[0045] In certain embodiments, the electrode assembly comprises an at least partially expandable support. Expanding the support places the electrode assembly in an expanded configuration, and contracting the support places the electrode assembly in an unexpanded configuration. For example, the support may include a gas conduit having spurring branches on which the electrodes are supported. Forcing gas into the gas conduit can switch the electrode assembly to an expanded configuration in which the branches fan out. The electrode assembly may also include a sufficiently weighted portion to remain submerged in the wastewater to be treated despite the introduction of air into the gas conduit.

[0046] In a second particular aspect of the present invention, there is provided an electrode assembly for use with a wastewater treatment system. Preferably, the electrode assembly is configured to be submerged within a wastewater treatment tank and includes a set of interconnectable electrode modules as described above with respect to the first aspect. Specifically, each electrode module includes at least one of the following: a first electrode consisting of an anode and cathode pair coated with electrogenic microorganisms adapted to generate electrons through consumption of organic matter in the wastewater; a second electrode consisting of an anode and a cathode pair; a body that ideally supports and separates the first and second electrodes; An interface for physically connecting the electrode module with at least one other electrode module.

[0047] Of course, the interface may also be arranged to electrically connect the first and second electrodes of the electrode module with the respective first and second electrodes of other connected electrode modules of the set.

[0048] In a third particular aspect of the present invention, there is provided a bioelectrochemical wastewater treatment process comprising at least one of: Providing an electrode assembly, for example by interconnecting a set of electrode modules; The electrode assembly is submerged in a wastewater treatment tank, the electrode assembly being positioned between the wastewater intake and the treated water outlet in the tank, the tank including the wastewater intake and the treated water outlet; and The electrodes of a set of electrode modules are electrically connected to an external power source or load via a circuit.

[0049] Ideally, or each electrode module includes at least one of the following: a first electrode consisting of an anode-cathode pair coated with electrogenic microorganisms adapted to generate electrons through consumption of organic matter in the wastewater; a second electrode consisting of an anode-cathode pair; a body that ideally supports and separates the first and second electrodes; an interface for physically connecting the electrode module with at least one other of the set, the interface may be further configured to electrically connect the first electrode and the second electrode of the electrode module with the respective first electrode and second electrode of the other connected electrode modules of the set; It will be understood that features and advantages of different aspects of the present invention may be combined with or substituted for one another where the context permits. For example, a feature of a system described in relation to the first aspect of the present invention may also be present on an electrode assembly described in relation to the second aspect of the present invention. Moreover, such a feature may itself constitute a further aspect of the present invention. For example, an electrode module of an electrode assembly of a system according to the first aspect may itself constitute a further aspect of the present invention. [Brief explanation of the drawings]

[0050] In order that the invention may be more readily understood, embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a schematic diagram of a wastewater treatment system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram of the system of FIG. 1 as seen from above. [Figure 3] FIG. 3 is a schematic diagram of a wastewater treatment system according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram of a first variant of the system of FIG. 3, seen from above. [Figure 5] FIG. 5 is a schematic diagram of a second variant of the system of FIG. 3, seen from above. [Figure 6] FIG. 6 is a schematic diagram of a wastewater treatment system according to a third embodiment of the present invention. [Figure 7] FIG. 7 is a schematic diagram of an electrode module used in any one of the wastewater treatment systems of FIGS. [Figure 8] FIG. 8 is a schematic diagram of a buoy for use in the wastewater treatment system of FIGS. [Figure 9] FIG. 9 is a schematic diagram of a weight used in the wastewater treatment system of any one of FIGS. [Figure 10] FIG. 10 is a schematic diagram of a wastewater treatment system according to a fourth embodiment of the present invention. [Figure 11] FIG. 11 is a schematic diagram of an alternative electrode module to that shown in FIG. [Figure 12] FIG. 12 is a schematic diagram of an alternative electrode module to that shown in FIG. [Figure 13] FIG. 13 is a schematic diagram of a wastewater treatment system according to a fifth embodiment of the present invention. [Figure 14] FIG. 14 is a perspective view of an electrode assembly having two identical sets of interconnected electrode modules in a further exemplary embodiment of the invention. [Figure 15]FIG. 15 is a perspective view of the electrode assembly of FIG. 14, showing the two electrode modules separated from each other. [Figure 16] FIG. 16 is a partial perspective view of the top ends of two electrode modules of FIG. 14 interconnected with one another. [Figure 17] 17 is a perspective view of the frame of one of the electrode modules of FIG. 14, defined by the holders and struts separated. [Figure 18] FIG. 18 is a perspective exploded view of one of the electrode modules of FIG. [Figure 19] FIG. 19 is a top view of the electrode module of FIG. [Figure 20] FIG. 20 is a partial perspective view of the top end of the electrode module of FIG. 19 showing the progression of the physical and electrical connections of the electrodes. [Figure 21] FIG. 21 is a partial perspective view of the top end of the electrode module of FIG. 19 showing the progression of the physical and electrical connections of the electrodes. [Figure 22] FIG. 22 is a partial perspective view of the top end of the electrode module of FIG. 19 showing the progression of the physical and electrical connections of the electrodes. [Figure 23] 23 is a partial side view of the arrangement of components of the electrode module shown in FIG. 21. FIG. [Figure 24] 24 is a perspective top view of the holder members of the electrode module of FIG. 14. FIG. [Figure 25] FIG. 25 is a perspective bottom view of the member of FIG. [Figure 26] FIG. 26 is a schematic diagram of a wastewater treatment system, the components of which are extensions to various embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0051] 1 is a schematic diagram of a wastewater treatment system 1 according to a first embodiment of the present invention. The system 1 includes a wastewater treatment tank 2 containing wastewater or organic waste 3 for treatment. The system 1 also includes an electrode assembly 4. The electrode assembly 4 includes a plurality of electrode modules 5, a circuit 6, and an external electrical device 7, which may be a power source or a load depending on the configuration of the system 1. The circuit 6 connects the external electrical device 7 to the electrode assembly 4.

[0052] System 1 further includes a buoy 8 that floats on the surface of wastewater 3 and supports electrode assembly 4. Within tank 2, above the surface of wastewater 3, is a gas headspace 23. Tank 2 includes a water intake 20 through which wastewater 3 passes into tank 2, an outlet 21 through which treated water is removed from tank 2, and a gas port 22 in communication with headspace 23.

[0053] In alternative embodiments, the tank is replaced by any suitable vessel or container for holding wastewater to be treated, and can take on different sizes, shapes, and configurations. For example, the tank of FIG. 1 can be replaced by bags from an anaerobic bag digester 2c, as shown in FIG. 13. In certain embodiments, the "tank" extends into a water reservoir or specially constructed wetland, with wastewater flowing into it via an upstream source and treated water flowing from a downstream source, and the "tank" being at least partially open at its top.

[0054] However, the tank 1 in the embodiment of Figure 1 is sealed so that gases produced by the bioelectrochemical process can be extracted from the headspace 23 via gas port 22 and thereby collected and utilized.

[0055] Alternatively, there may be multiple inlets, outlets, and gas posts. Additionally, the tank may be divided into a series of adjacent chambers, which forces the wastewater to follow a non-linear path between the inlets and outlets, thereby advantageously increasing the treatment period and increasing contact between the wastewater and the electrode assemblies.

[0056] The electrode assembly 4 is submerged in the wastewater 3 of the wastewater treatment tank 2 between an inlet 20 and an outlet 21. The electrode assembly 4 has seven sets of electrode modules 5, only four of which are shown schematically in FIG. 1. Each electrode module 5 is identical and interconnected with adjacent electrode modules in the same set. While there are advantages associated with mass production of identical electrode modules 5, it will be appreciated that in alternative embodiments, the electrode modules need not be identical.

[0057] FIG. 7 is a schematic diagram of one of these electrode modules 5. Each electrode module 5 comprises electrodes including a first electrode 51 that functions as the anode 51 of an anode-cathode pair and a second electrode 52 that functions as the cathode 52 of an anode-cathode pair. The anode 51 is provided with a biocoating of electrogenic microorganisms adapted to generate electrons through the consumption of organic matter in wastewater. The coating includes a heterogeneous culture of electromethanogenic microorganisms that can produce both electricity and methane through the consumption of organic matter in wastewater. The cathode of the anode-cathode pair is not coated with microorganisms in this embodiment, but this may alternatively be the case. Each electrode module 5 also includes a body 50 that supports the first and second electrodes. The body 50 is a flexible, porous, and elongated structure that physically and electrically separates the anode, located on one flat surface of the body 50, from the cathode, located on the other flat surface of the body 50.

[0058] Figures 11 and 12 are schematic diagrams of an electrode module that replaces the electrode module shown in Figure 7. As can be seen, the flexible body 50 allows for rolling of the electrode module 5, which allows for easy transport and configuration flexibility. This also allows for easy incorporation of the electrode into various tanks through small ports in the tank 2. Figures 11a, 11b, 11c, and 11d show alternative shapes that the electrode module can take to fit a particularly shaped tank 2.

[0059] Referring to FIG. 7 , each electrode module 5 includes an interface 53 that can connect to two other electrode modules 5. The elongated body 50 of the electrode module 5 defines first and second ends, each of which includes a portion of the interface 53. Specifically, the interface 53 includes a plug 54 disposed toward the first, upper end of the electrode module 5 and a socket 55 disposed toward the second, lower end of the electrode module 5. The plug 54 and socket 55 are complementary and allow for a push-fit connection between adjacent electrode modules 5 within a pair, which electrically and physically connects the adjacent electrode modules 5 to each other. Alternatively, other quick-release couplings or fasteners can be used to form the connection. A latch is also provided as part of the plug-and-socket arrangement to prevent unintentional disconnection. The fastening method allows the electrode modules to be distributed and adapted to various container shapes.

[0060] In alternative embodiments, the interface may include other complementary coupling members instead of the plug 54 and socket 55. Nevertheless, the interface serves to electrically connect corresponding electrodes 51, 52 of the interconnected electrode modules 5. Thus, in each set of electrode modules 5, all of the first electrodes 51 (anodes) are electrically connected to each other, and independently of this, all of the second electrodes 52 (cathodes) are electrically connected to each other.

[0061] 1, each set of electrode modules 5 is suspended between a ball float 81, which acts as a buoying member of the buoy 8, and a weight 9. To this end, each ball float 81 and weight 9 has a connector that allows the chain of sets of electrode modules 5 to be linked.

[0062] 8 is a schematic diagram of the ball float 81, and FIG. 9 is a schematic diagram of the weights 9, each separated. The ball float 81 includes a connector 85, similar to the socket 55 of the electrode module 5, in that it can be complementary connected to the plug 54 of the electrode module 5. Furthermore, the connector 85 electrically couples to the power source or circuit 6 leading to the load 7. Advantageously, this allows for easy assembly of the system, as only a single connection is required. The weight 9 also includes a connector 94, similar to the plug 54 of the electrode module 5, in that it can be complementary connected to the socket 55 of the electrode module 5.

[0063] Returning to FIG. 1, each ball float 81 and buoy 8 generally floats on the surface of the wastewater 3 in the tank 2, with each set of electrode modules suspended from the buoy 8 and submerged in the wastewater to be treated by a weight 9, with each interconnected set of electrode modules 5 positioned vertically between the buoy 8 and the weight 9.

[0064] Figure 2 is a schematic diagram of the interior of the tank 2 shown in Figure 1, viewed from above. Referring to Figure 2, a matrix of seven ball floats 81 are held equally spaced from one another by separating struts 82 which also allow electrical connection of each set of electrode modules 5 to the circuit 6. The even spacing prevents short circuits and also promotes optimal distribution of the electrode module sets, thereby facilitating wastewater treatment facilities throughout the tank 2.

[0065] In alternative embodiments, different component arrangements are possible: FIG. 3 is a schematic diagram of a wastewater treatment system 1 according to a second embodiment of the present invention. Similar components are designated by the same reference numerals. In this second embodiment, the buoy 8 is not composed of individual buoy members 81, but rather of a single unit in the form of an inflatable bladder. While a side view of an inflatable bladder buoy 8 is shown schematically in FIG. 3, it will be understood that many variations and shapes of such a buoy 8 are possible. FIGS. 4 and 5 are schematic top views of the system of FIG. 3 incorporating two exemplary variations of buoys 8a, 8b. In each case, separating struts are not required but can be used, and connectors 85 for suspending each set of electrode modules 5 are simply located on the underside of the bodies of the buoys 8a, 8b at different spaced positions, as outlined by dashed lines in FIGS. 4 and 5.

[0066] In a further alternative, the buoys may be constructed of a low-density material. However, an advantage of the inflatable bladder variant is that they can be deflated to take up a small amount of space for transportation and then inflated on-site for use. Similarly, the individual ball floats of the first embodiment may be inflatable. Also, in alternative embodiments, the weights may have alternative arrangements. For example, the weights 9 for each set of electrode modules may be freely hanging, as in FIGS. 1 and 3, or may be connected to each other by struts and separated from each other. In the latter case, this preferably coincides with the separation at the top of the electrode sets, so that each set of electrodes is suspended between the weights and the buoy in an ideally vertical and parallel orientation. As mentioned above, this allows for optimal even distribution throughout the wastewater treatment plant's tanks and also prevents short-circuiting of the electrodes.

[0067] However, in some cases, it may be advantageous to select an uneven distribution of electrode modules. Figures 1 and 3 show an upflow tank in which the intake 20 is located at the bottom of the tank and the outlet 21 is near the top, so that the fluid flow is generally vertical. As mentioned, other tank designs are possible and compatible with the present invention, and alternative electrode module distributions may be more appropriate.

[0068] 6, for example, is a schematic diagram of a wastewater treatment system according to a third embodiment of the present invention, showing a lateral flow tank 2a in which the wastewater fluid flows generally horizontally. In a further alternative, the tank may be compartmentalized with the flow of the wastewater fluid being forced along a non-linear (typically up and down) path.

[0069] In FIG. 6, the sets of electrode modules are intentionally unevenly distributed, with irregularly spaced electrode modules 5 spaced wider closer to the intake and narrower closer to the outlet. Advantageously, the higher the density of organic matter passing through the intake, the greater the likelihood of clogging. Thus, providing wider spacing near the intake offsets this risk. As the wastewater moves through the tank toward the outlet, the density of organic matter decreases. Therefore, it is advantageous to decrease the spacing between the anode-cathode pairs defined by the electrode modules to proportionally increase treatment effectiveness. Finally, it is beneficial for the spacing to be widest nearest the intake 20 and narrowest nearest the outlet 21.

[0070] Similar advantages can be realized in an upflow reactor with reference to Figure 10, which is a schematic diagram of a wastewater treatment system according to a fourth embodiment of the present invention, where the electrode density increases from bottom to top, i.e., towards the outlet.

[0071] Further embodiments may replace the buoys and / or weights with a frame or support that is insertable into the tank 2, the frame holding and maintaining the electrode modules 5 at a particular position within the tank 2 in a particular arrangement.

[0072] Further embodiments may include tanks that are open at their tops. In such alternatives, the system preferably further comprises a gas trap configured and arranged to capture gases released by the electrode assembly, particularly from the electrodes of the anode-cathode pair defined by the set of one or more electrode modules. The gas trap is ideally configured to attach to the electrode assembly above the electrode modules to capture gases such as methane and / or hydrogen. Advantageously, this allows flexibility in the selection of the wastewater tank; i.e., the gas port 22 need not necessarily be sealed or even included.

[0073] Particularly contemplated is the deployment of certain aspects of the system in outdoor environments, such as wetland environments. In such embodiments, the gas trap and / or buoy typically float on the surface of the wastewater being treated. Additionally, they can support other components of the system, such as an external power source or load 7. For example, a solar panel can be supported and connected to the electrode module. A further advantage resides in contacting or circulating water across the back of the solar panels, which has the benefit of cooling them and thereby increasing their performance. This also typically increases the temperature of reaction sites adjacent to the system's electrodes, again improving reaction efficiency and, therefore, the efficiency of decomposition of organic matter in the wastewater.

[0074] To facilitate retrofitting of electrode assemblies into vessels such as anaerobic bag fermenters, as shown in FIG. 13, embodiments of the present invention may allow the electrode assembly to be switched between an unexpanded and an expanded configuration. In the unexpanded configuration, the electrode assembly occupies a small volume and can therefore be easily inserted into such vessels. The electrode assembly can then be switched to the expanded configuration to increase its volume and thereby maximize the effectiveness of the electrodes.

[0075] In certain embodiments, the electrode assembly comprises an at least partially expandable support that, when expanded, places the electrode assembly in an expanded configuration and when contracted, places the electrode assembly in an unexpanded configuration. For example, the support may include a gas conduit having spurting branches on which the electrodes are supported. Forcing gas into the gas conduit can switch the electrode assembly to an expanded configuration in which the branches separate and fan out. The electrode assembly may also include a sufficiently weighted portion to remain submerged in the wastewater to be treated despite the introduction of air into the gas conduit.

[0076] In other embodiments, the expanded configuration can be defined by electrode modules that can be connected together with fixed supports that fit into containers of a particular size and shape, thereby expanding the surface area of the working electrodes.

[0077] In each of the described embodiments, circuitry 6 electrically connects the electrodes 5 of each set of electrode modules to a power source or load 7. System 1 can be configured to control switching between power sources or loads depending on the configuration of the bioelectrochemical system thus defined. The electrical load can include another system according to an aspect of the present invention. Thus, the circuits of different systems may be interconnected, for example, with system 1 configured as an MFC supplying power to a system configured as an MEC.

[0078] The resulting modularity of System 1 is particularly advantageous and overcomes, at least in part, the shortcomings of existing BESs described in the preamble. For example, because electrode assembly 4 can be configured with different combinations of electrode modules 5, its size, shape, and capacity can be adapted to a variety of different profiles of wastewater treatment tanks. Furthermore, embodiments of System 1 can be applied to anaerobic bag fermenters and thus used to enhance their operation, particularly for biogas generation.

[0079] 14 is a perspective view of an electrode assembly 4 according to another embodiment of the present invention, having a set of two identical interconnected electrode modules 5, which can be substituted for the electrode modules described above in various systems illustrating the present invention.

[0080] Figure 15 is a perspective view of the electrode assembly of Figure 14, with the two electrode modules 5 shown separated from each other. Each electrode module 5 has eight separate electrodes defined by four brush anodes 51 and four pocket cathodes 52. Note that in alternative embodiments, the electrodes designated as anodes can instead be used as cathodes, and vice versa.

[0081] The electrodes 51, 52 are elongated in shape, each generally defining a longitudinal axis. The electrodes 51, 52 are connected to a pair of wide, L-shaped electrode holders 10 that slide into locking engagement with one another, as shown in the partial perspective view of FIG. 16 . In particular, each holder 10 has complementary sliding and snap-fit interfaces 10s and 10i that allow the electrode modules 5 to slide and lock together as a whole. The holders 10 for each electrode module 5 are joined back-to-back to form a wide, cross-shaped configuration. Thus, the electrode assembly 4, consisting of two joined electrode modules 5, collectively comprises a cluster of 16 electrodes.

[0082] Each electrode module 5 comprises a set of elongated struts 35 of box-shaped cross section which join together with the electrode holder 10 to define a frame for holding and maintaining the position and alignment of the electrodes 51, 52. Figure 17 shows the frame of the electrode module 5 defined by the holder 10 and a portion of the struts 35.

[0083] 14, electrodes 51 and 52 are secured to a first upper holder 10a, through a second intermediate holder 10b, and onto a third lower holder 10c, with their longitudinal axes held parallel to one another. Elongated struts 35 similarly straddle the holders 10a, 10b, and 10c, aligning with the electrodes and providing frame rigidity and preventing pivotal movement where the holders 10 are connected to the electrodes.

[0084] Thus, the posts 35 and holder 10 function similarly to the body 50 of the electrode (e.g., FIG. 7 above), particularly in terms of supporting and separating the electrodes 51, 52 from one another. However, while the aforementioned body 50 is flexible, the posts 35 and holder 10 are rigid. Nevertheless, the electrode module 50 can be easily assembled and disassembled, allowing for modular expansion of the electrode assembly 4 to be used across a wide range of applications, including relatively small-scale BES suitable for remote facilities, or convenient retrofitting to existing waste treatment infrastructure.

[0085] 18 is a perspective exploded view of one of the electrode modules 5, illustrating how the various components of the electrode module 5 can be assembled together. As shown, the electrode module 5 further includes a set of flanged nuts 36, end caps 37, flanged bolts 38, and titanium anode conductors 13 and cathode conductors 14.

[0086] The upper and lower holders 10a, 10c are two-piece structures with respective inner members 10x, 10y adjacent the electrodes 51, 52 and respective outer members 10w, 10z at the outer ends of the electrode module 5. The holder members 10w-10z and the intermediate holder 10b are each made from a single piece of injection-molded plastic material. The walls 10p and webs 10q extend along vertical planes, which facilitates easy removal from the mold during manufacturing. The inner and outer members 10w-10z can be made from a common mold, reducing manufacturing cost and complexity.

[0087] The inner and outer members 10w-10z define a pair of central bolt holes through which the threads of corresponding flanged bolts 38 can pass into nuts 36 on the support posts 35. Each box-section support post 35 has an end cap 37 securely fastened (e.g., welded) to the interior of its other hollow end, which encloses a flanged nut 36. Thus, by threading the bolts 38, each pair of inner and outer members can be clamped together and securely fastened to its respective support post 35. The upper holder 10a further clamps the conductors 13, 14 in place such that the anodes 51 are electrically connected to each other via the first anode conductor 13 and the cathodes 52 are electrically connected to each other via the second cathode conductor 14.

[0088] Each anode electrode 51 is a brush electrode, having a twisted wire core that runs through and terminates at each end in a wire loop 51a. The conductive brush filaments captured by the wire core extend radially outward from the core at regular lengths, resulting in the electrode 51 forming a wide, cylindrical brush along substantially its entire longitudinal length. The filaments of the brush anode 51 are biocoated with electrogenic microorganisms for consumption of organic matter in the wastewater 3. The brush provides a convenient way to maximize the surface area-to-volume ratio of the anode 51, allowing for a relatively high rate of organic waste consumption.

[0089] Each cathode electrode 52 is a pocket electrode, a hollow, marine-grade stainless steel structure whose shape resembles a flattened tube with a crimped end 52a. The pocket is filled with conductive granular activated carbon (GAC), representing a way to increase the electrode's surface area and, over time, promote the growth of microorganisms that aid in the breakdown of waste materials. The walls of the pocket electrode are meshed or perforated to allow wastewater to enter the pocket, while the GAC is retained during operation.

[0090] The crimped end 52a of the cathode 52 and the loop 51a of the anode are the attachment points of the electrodes. They are conductive and act as physical and electrical attachment joints to hold the electrodes in place and allow connection to the circuit 6.

[0091] 19 shows the electrode module 5 from above, including the upper holder 10a to which the electrodes 51, 52 and support posts 35 are connected. The top member 10w of the holder 10a is omitted for clarity. The sliding interface 10s includes cooperating rail and bracket arms. The snap-fit interface 10i includes resilient hook arms whose ends rest within hook pits.

[0092] Figures 20, 21 and 22 are partial perspective views of the top end of the electrode module 5 of Figure 19, showing the progressive assembly of components to enable physical and electrical connection of the electrodes 51, 52. Figure 23 is a partial side view of the arrangement of components shown in Figure 21.

[0093] FIG. 24 is a top perspective view of the member 10w of the upper holder 10a, and FIG. 25 is a bottom perspective view of the member 10w of the upper holder 10a, showing the conductors 13 and 14 fitted into their respective tracks. The tracks are defined by notches in the web 10q that crisscross the peripheral wall 10p of the holder member 10w. The track housing the upper outer conductor 13 is surrounded by a protrusion 10r that hooks underneath the anode conductor 13, preventing it from falling out of the track once positioned. This keeps the anode conductor 13 elevated and out of contact with the end 52a of the cathode 52. The conductors 13 and 14 are sufficiently resilient so that they snap back into shape. This allows the anode conductor 13 to be deflected past the protrusion 10r and snap into its respective track.

[0094] 19-25, conductor tracks are defined within the upper holder 10a to accommodate the conductors 13, 14. The anode conductors 13 follow outer and upper tracks that pass through the wire loops 51a of each anode 51, compressing them into each wire loop 51a during assembly, thereby ensuring reliable electrical contact between each anode 51 and the anode conductor 13. The cathode conductors 14 follow inner and lower tracks that pass through the crimped ends 52a of the cathodes 52. The upper anode conductors 13 pass over the crimped ends 52a of each cathode 52, but are vertically separated so as not to contact them. Tightening the bolts 38 clamps the first and second members 10w, 10x of the upper holder 10a together, compressing the cathode conductors against the flat surfaces of the crimped ends 52a of the cathodes 52, again ensuring reliable electrical contact.

[0095] Conductors 13, 14 lead to a central junction area 10j, with the end of each conductor turning upward to effectively define a prong to which a socket in the central junction box 56 (as shown in Figure 14) can be connected, which in turn leads to circuit 6, as described above.

[0096] Each of the upper holder 10a, the middle holder 10b, and the lower holder 10c has spaced slots defined therein to accommodate the spaced connections of the electrodes 51, 52. Thus, each holder defines a plurality of spaced connection areas that releasably hold each electrode.

[0097] The electrodes 51 and 52 are inserted into position by lateral sliding of the vertically oriented electrodes relative to the vertically oriented frame defined by the support posts 35 and the holders 10a, 10b, and 10c. Such lateral sliding thus occurs along a plane perpendicular to the longitudinal axis of each electrode 51 and 52. To enable this, each of the slots is led laterally inward from the peripheral wall 10 and bounded by a web 10q. Additionally, the slots for the wire loop ends 51a of the anode 51 each terminate in a T-shaped recess 10t bisected by a central lateral divider. In the case of the upper holder 10, the divider of the inner (lower) member 10x acts as a seat to support the underside of the loop 51a, the upper half of which projects upward to contact the conductor 13. When the outer (upper) member 10w is lowered over the inner clamping member 10x, a T-shaped recess on the underside of member 10w forms a hood over the upper half of wire loop 51a, enclosing it and preventing removal.

[0098] Nevertheless, once the members 10w, 10x are separated, the slots allow the electrodes 51, 52 to be easily slid onto the holder 10, facilitating quick assembly of each electrode module 5 and, conversely, allowing quick disassembly or replacement of the electrodes, for example, for maintenance purposes.

[0099] Advantageously, the cathodes 52 are connected to the upper and lower holders 10a, 10c with the crimped ends 52a of adjacent cathodes oriented perpendicular to one another, which strengthens the resulting structure and makes it less prone to twisting or twisting at the joints between the electrodes and holders.

[0100] Referring to FIG. 14, the electrode assembly 4 also includes an outer shell 30 made of multiple elastic fiberglass rods 31 helically wound around an internal volume containing a cluster of electrodes 51 and 52. The rods 31 terminate at both ends in connecting eyelets 32 that snap into lugs 11 defined around the upper and lower holders 10a and 10c. When interconnected, the lugs 11 and eyelets 32 can rotate relative to one another. The intermediate holder 10b defines a channel 12 through which the rods pass and are retained by the intermediate holder 10c. The rods 31 are bent to wrap around the holder 10c, which introduces elastic tension into the rods 31, keeping them in place relative to the holder and ensuring that the resulting shell 30 defined by the rods is elastic. Thus, the shell 20 acts as a barrier between the electrodes 51 and 52 and structures, such as other electrodes, that could potentially cause short circuits.

[0101] Thus, the shell 30 advantageously allows different sets of similar electrode assemblies to be installed in tanks of various sizes, shapes, and configurations without the need to rigidly fix each one of the electrode assemblies in place, thereby increasing the flexibility and modularity of the system.

[0102] The shell 30 protects the electrode assembly from contact with other items, but it is a primarily open structure, allowing waste 3 to flow freely through and throughout the electrodes 51, 52.

[0103] This electrode assembly and other electrode assemblies 4 described herein can be used in a variety of wastewater treatment systems, further extended examples of which are described herein.

[0104] FIG. 26 is a schematic diagram of a wastewater treatment system 1 that is an extension to various embodiments of the present invention.

[0105] The system 1 has features in common with those described above, namely a wastewater treatment tank 2 in which wastewater or organic waste 3 is contained for treatment, an electrode assembly 4 with a plurality of electrode modules 5, and a circuit 6 connecting them to an external electrical device 7. However, additional components make it possible to realize specific advantages and functions for specific use cases.

[0106] For example, system 1 can function as a portable electro-methanogenic reactor (EMR) for waste treatment, bioenergy recovery, nutrient (e.g., nitrogen (N), phosphorus (P), and potassium (K)) extraction, and water recovery. This system 1 outputs useful electricity, biogas, and fluid products.

[0107] To this end, the system further comprises a pretreatment tank 120 configured to pretreat the wastewater or organic waste before introducing the wastewater 3 into the wastewater treatment tank 2 containing the electrode module 5. A first pump 19 controls the flow rate from the pretreatment tank 120 to the wastewater tank 2 via a water intake 20, and similarly a second pump 18 controls the flow rate from an external source to the pretreatment tank 120.

[0108] It should be noted that in certain embodiments, the pretreatment tank may also contain electrodes, typically for the purpose of developing a different microbial community optimized to degrade the waste to a certain point under different operating conditions than the main reaction tank 2 and prior to introduction into the main tank 2.

[0109] Other actuators, such as additional pumps and valves, may also be provided. In particular, in this embodiment, the system 1 comprises a pre-treatment actuator 121 in the form of a heater configured to heat the contents of the tank 120 to within a predetermined temperature range. Alternatively, and depending on the use case, the pre-treatment actuator 121 may instead or in addition comprise a mechanical breakdown actuator (e.g., a grinder).

[0110] The pretreatment process depends on the feedstock composition and aims to modify its structure and properties to improve biomass utilization by enzymes and microorganisms. Different methods include physical, thermal (high temperature, 50-80°C), chemical, or biological (i.e., fungal or fermentative). These are selected depending on the feedstock and application. For example, fecal sludge pretreatment benefits from operating the heater 121 to achieve a thermophilic temperature range and kill pathogens in the pretreatment tank 120. Fecal sludge pretreatment also accelerates the hydrolysis stage of waste decomposition, which causes a decrease in pH, before entering the primary reactor, where the waste can be further decomposed through various stages to achieve methanogenesis.

[0111] Following pumping from the pretreatment tank 120 to the main tank 2 containing the electrode modules 5, mechanical breakdown of the solid waste, such as with a grinder, can enhance microbial degradation of organic compounds. Mechanical breakdown of the waste aids in its interaction with the electrode surface area. Contact with biofilms capable of decomposing the waste is improved, as is mass transfer interaction between the waste and the electrode surface. Mechanical breakdown of the waste increases the effectiveness of internal mixing within the EMR reactor, increasing mass transfer on the electrodes. Increased mixing due to initial mechanical breakdown of the waste helps prevent biofouling. Specifically, mixing minimizes biofilms on the electrodes that increase in thickness beyond a certain threshold (measured in microns), which reduces energy recovery efficiency. Increased mixing effectiveness allows for optimization of shear forces to stimulate removal of dead biofilms on the electrode surface, reducing maintenance and cleaning requirements. Alternatively, biological pretreatment, such as fungal or fermentation processes, can be used.

[0112] When configured as an EMR, the system 1 also includes a gas scrubbing component. In particular, the gas port 22, through which gas is extracted from the headspace 23, is connected to a gas scrubber 122 configured, among other things, to remove hydrogen sulfide. Carbon dioxide can also be scrubbed. To this end, the gas scrubber 122 can use a gas scrubbing medium with a high surface area to volume ratio, such as GAC (granulated activated carbon) or equivalent (e.g., iron), and / or can use catalytic methods. Silica scrubbing can also be performed by the scrubber 122 to reduce moisture. Once scrubbed, the gas can be transferred to a gas reservoir 124 for storage prior to use.

[0113] The system 1 also outputs a treated product, such as water, via treated water outlet 21. This is typically filtered through a multi-stage filter, e.g., using GAC (granulated activated carbon), microfilters (0.004-0.1 microns) to remove helminth eggs, pathogens, and viruses, and may also be subjected to pasteurization, ultraviolet irradiation, chlorination, and / or ozonation for this purpose. The water can then be supplied to product reservoir 130.

[0114] Other useful products besides water can also be output (e.g., fertilizer), and these can have their own outlets and reservoirs, but for simplicity only a single outlet 21 and product reservoir 130 are shown. On the other hand, post-treatment of the solids settled in the main reaction tank 2, located in a settling chamber (not shown), can be circulated into a thermophilic EMR tank operating at low temperatures, which pasteurizes the waste so that it is safe to discharge into the environment and can be used as a soil conditioner or fertilizer.

[0115] The system 1 also generates electrical energy via the circuit 6 which can be delivered to a load 7 which can charge an electrical energy store 110 .

[0116] System 1 may be optimized for the output of one or more of these products and / or for efficient operation in general. For example, biogas generation, organic matter removal, or biofilm growth may be optimized. To this end, system 1 further comprises a controller 100 and a set of sensors 102, 103, and 104. As a schematic example, as shown in FIG. 26, a first sensor 102 is located in pretreatment tank 120, a second sensor 103 is located in wastewater tank 2, and a third sensor 104 is located in gas scrubber 122. However, it will be understood that sensors may be located in different locations (e.g., between tanks, in headspace 23, as part of each electrode module 5), and that multiple sensors may be used per location.

[0117] Additionally, the sensor itself may have self-regulating properties independent of the controller 100. For example, the electrode module 5 may include three wires that connect to a modular potentiostat. Two of these wires apply set voltages to the anode and cathode, while the third connects to a reference electrode. The reference electrode allows the potentiostat to adjust the applied voltage in response to biofilm growth on the electrode module.

[0118] Nevertheless, as a general principle of operation, the controller 100 receives signals from sensors that indicate properties of the materials (e.g., feedstock, wastewater, gas) that the system handles. Properties detected by the sensors or that can otherwise be inferred by the controller 100 from these properties may include temperature, liquid turbidity, electrode current density, electrode voltage potential, biogas composition (particularly the percentages of methane, carbon dioxide, hydrogen, and hydrogen sulfide), biogas flow rate, pH, alkalinity, amount of VFA (volatile fatty acids), COD (chemical oxygen demand), and BOD (biochemical oxygen demand).

[0119] It should be noted that COD and BOD often require manual laboratory testing; however, these metrics can be inferred automatically and in real time by system 1. Electrode modules are placed in different locations relative to the intake 20 and outlet 21 within wastewater treatment tank 2. Sensors allow for measurement of electrode current densities at two different locations (e.g., one near intake 20 and the other near outlet 21). These are used by controller 100 to determine the difference between the electrode current densities and, therefore, infer the oxygen demand and quality of the effluent leaving outlet 21.

[0120] In response to the sensor data, the controller 100 is configured to adjust the system treatment accordingly (e.g., heating, physical action, fluid flow rate, electrode voltage / current). For example, the controller 100 is communicatively coupled to the pump 19 to control the flow rate to the wastewater tank 2. Similarly, the controller 100 is communicatively coupled to the pretreatment actuator 121 to control the applied heat level and / or rate of the physical treatment. In another embodiment, a dosing pump can be used to introduce an amount of buffer solution in response to, for example, pH level. The controller 100 may also include a clock to automate scheduling, for example, when feedstock is pumped via the pump 18 to the pretreatment tank 120.

[0121] Generally, the controller 100 is configured to slow down the flow rate to each tank 120,2 via pumps 18,19 in response to detecting higher COD or VFA content and / or low pH (i.e., pH less than 6) in the wastewater, and vice versa.

[0122] Furthermore, the controller 100 is configured to control the voltage applied to the electrode module to control the pH, increasing or decreasing the applied voltage to increase or decrease the production of hydrogen ions, thereby enabling the controller 100 to responsively and intelligently control the pH without the need for adding a buffer solution.

[0123] Additionally, the controller 100 is configured to increase the flow rate in response to detecting a decrease in current density at the electrode module over time, which is an indicator that the amount of organic matter in the wastewater 3 is also decreasing. Thus, a higher flow rate can be maintained by the controller 100.

[0124] Also, by sensing changes in current density (and biofilm growth), the controller 100 can adjust the power distribution to the electrode modules 5. To this end, each module 5 may be connected individually or with a localized controller that allows each module to draw exactly how much power it needs from one shared cable.

[0125] Thus, storage in the electrical energy storage unit 110, gas storage 124, and other product storage 130 can be established and accessed by consumers via corresponding electrical outlets 112, gas outlets 126, and product outlets 136, respectively.

[0126] The features described above in connection with FIG. 26 typically relate to components of system 1 at a particular wastewater treatment site, executed by one controller 100. However, other controllers 100a may be deployed at other sites. Thus, system 1 can be tailored to different sites and use cases. This relates to how each controller 100, 100a is configured to control the hardware at each site, as well as the hardware itself. For example, agricultural waste treatment uses larger pipes and does not require pre- and post-treatment heating (i.e., pathogen kill is less relevant). For industrial applications, more intensive wastewater treatment may be appropriate. Filters for filtering smaller particle sizes allow for the use of smaller pipes. For sanitary waste treatment, a higher pathogen kill configuration is more appropriate (and therefore higher heating temperatures can be applied).

[0127] Nevertheless, an additional complementary feature set for all of these use cases, illustrated in FIG. 26, is the additional use of a remote server 210 that can perform central remote monitoring of each controller 100, 100a, and each site, as such.

[0128] Specifically, each controller 100, 100a further includes a communications module that allows it to exchange data (including all sensor and control data) with a remote server 210 via a network 200 (e.g., the Internet). The remote server 210 includes a user interface 220. The user interface 220 allows monitoring and control staff to monitor the status of each site and send configuration instructions to each controller 100, 100a to reconfigure each controller and improve control at each site. Such monitoring enables predictive component use and allows maintenance to be performed at the right place and at the right time. This enhances the benefits discussed above, particularly with regard to the modularity of the electrode module 5, allowing for better and more timely parts collection, replacement, and reuse.

[0129] Additionally, the server 210 can interface with end-user devices 230 (e.g., via a mobile app or web application) to enable end-user monitoring and control. Specifically, the end-user can view key metrics related to the local BES (e.g., energy generation) and receive simple alerts related to routine maintenance. Furthermore, the end-user devices 230 can be configured to allow customers to purchase resources output by the local BES. This allows for metering of the electric outlets 112, gas outlets 126, and product outlets 136. A user submits a payment and request to the server 210 for access to resources at a particular site, and in response to payment confirmation, the server 210 instructs the controller 100 at that site to unlock each outlet 112, 126, 136 for a predetermined usage period or quantity.

[0130] While the present invention has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the scope of the appended claims.

Claims

1. In a bioelectrochemical wastewater treatment system (1), a wastewater treatment tank (2) having a wastewater intake (20) and a treated water discharge (21); an electrode assembly (4) configured to be submerged in the wastewater treatment tank (2) between the water intake (20) and the discharge (21); A circuit (6), Equipped with The electrode assembly (4) comprises a series of interconnectable electrode modules (5), Each of the electrode modules (5) comprises: a first electrode (51) consisting of an anode and cathode pair coated with electrogenic microorganisms adapted to generate electrons through consumption of organic matter in wastewater; a second electrode (52) consisting of an anode and a cathode pair; a body (50) supporting and separating the first electrode and the second electrode; an interface (53) for physically connecting the electrode module with at least one other electrode module, the interface being configured to electrically connect the first electrode and the second electrode of the electrode module with the first electrode and the second electrode of each of the other electrode modules, the interface having a readily detachable coupling member for coupling with a complementary coupling member of the other electrode module; The circuit electrically connects the electrodes of the series of electrode modules to an external power source or load (7).

2. each said electrode being elongated so as to define a longitudinal axis; 2. The bioelectrochemical wastewater treatment system of claim 1, wherein the first electrode and the second electrode are held by the body such that their respective longitudinal axes are parallel to one another.

3. 3. The bioelectrochemical wastewater treatment system of claim 1 or 2, wherein each of the electrode modules further comprises a plurality of holders at least partially defining the body for supporting and separating the electrodes.

4. At least one pair of said holders are fixedly spaced apart from each other by at least one elongated post to define an elongated framework; 4. The bioelectrochemical wastewater treatment system of claim 3, wherein each of the electrodes is held within the framework such that a longitudinal axis of the framework and a longitudinal axis of the electrode are parallel to each other.

5. 5. The bioelectrochemical wastewater treatment system of claim 3 or 4, wherein each said holder defines a plurality of spaced apart connection areas for releasably holding a respective electrode.

6. 6. The bioelectrochemical wastewater treatment system of claim 5, wherein the connection region of each holder comprises a plurality of slots capable of enclosing a mounting portion of each electrode to prevent relative movement of each electrode.

7. 7. The bioelectrochemical wastewater treatment system of claim 6, wherein the mounting portions of the electrodes are slidable into and out of their respective slots during installation or removal of the electrodes.

8. 7. The bioelectrochemical wastewater treatment system according to claim 5 or 6, wherein the electrode attachment portions are electrically conductive.

9. At least one of the plurality of holders has a pair of conductive tracks; 9. The bioelectrochemical wastewater treatment system of claim 3, wherein each conductive track has a conductor for electrically connecting to a respective electrode, a first track operating through the first electrode, and a second track operating through the second electrode.

10. At least one of the plurality of holders has a clamp portion, 10. The bioelectrochemical wastewater treatment system of claim 3, wherein the clamping portions have a clamping structure that compresses the clamping portions toward each other to capture the electrodes in place.

11. 11. The bioelectrochemical wastewater treatment system of claim 10, wherein the clamping portion compresses the first and second conductors against the first and second electrodes of each of the plurality of modules in the clamping configuration.

12. 12. The bioelectrochemical wastewater treatment system of claim 9, wherein the combination of the holder and the conductor at least partially constitutes the interface (53) for physically and electrically connecting the electrode module with at least one other electrode module.

13. 13. The bioelectrochemical wastewater treatment system according to any one of claims 1 to 12, wherein the coupling members of the interface (53) of each electrode module have a first complementary coupling member and a second complementary coupling member, one of the first complementary coupling member and the second complementary coupling member being a plug and the other being a socket.

14. The body (50) of each electrode module is elongated having a first end and a second end; 14. The bioelectrochemical wastewater treatment system of claim 13, wherein the first and second complementary coupling members of the interface of each electrode module are disposed toward the first and second ends of the body, respectively.

15. a buoy (8) for floating within the wastewater treatment tank; 15. The bioelectrochemical wastewater treatment system of any one of claims 1 to 14, wherein the buoy has connectors constructed and arranged to connect with the interfaces of the interconnectable series of electrode modules, thereby suspending the series of electrode modules from the buoy in use.

16. 16. The bioelectrochemical wastewater treatment system of claim 15, further comprising a weight (9) having connectors (94) constructed and arranged to connect with the interfaces of the interconnectable series of electrode modules, thereby, in use, retracting the electrode assembly into a vertical position between the buoy and the weight.

17. The electrode assembly (4) has at least two sets of interconnectable electrode modules, the buoy has at least two corresponding connectors for connecting with each of the electrode modules; 17. The bioelectrochemical wastewater treatment system of claim 15 or 16, wherein at least two of the connectors are spaced apart from one another on the buoy to separate the electrode modules from one another in use.

18. The bioelectrochemical wastewater treatment system according to any one of claims 15 to 17, wherein the buoy (8) is a swim bladder.

19. The wastewater treatment tank (2) has an open top end, 19. The bioelectrochemical wastewater treatment system of claim 1, further comprising a gas trap configured to be attached to the electrode assembly above the electrode module, the gas trap capturing gases released by each electrode of the anode and cathode pairs.

20. The wastewater treatment tank (2) has an open top end, a gas trap configured to be attached to the electrode assembly above the electrode module and configured to capture gases emitted by each electrode of the anode and cathode pairs; The bioelectrochemical wastewater treatment system according to any one of claims 15 to 18, wherein at least one of the gas trap and the buoy supports the external power source or the load.

21. A bioelectrochemical wastewater treatment system as described in claim 20, wherein at least one of the gas trap and the buoy supports the external power source, and the external power source has a solar panel.

22. The electrode assembly (4) has a plurality of the electrode modules (5) arranged between the water intake (20) and the water outlet (21); 22. The bioelectrochemical wastewater treatment system according to any one of claims 1 to 21, wherein the spacing between the anode and cathode pairs defined by the electrode module (5) is widest closest to the water intake and narrowest closest to the outlet.

23. the electrode assembly (4) being switchable between an unexpanded configuration and an expanded configuration; the electrode modules of the electrode assembly occupy a smaller volume in the unexpanded configuration than in the expanded configuration; The electrode assembly (4) has a support that is at least partially expandable, 23. The bioelectrochemical wastewater treatment system of any one of claims 1 to 22, wherein the electrode assembly is in the expanded configuration when the support is expanded and the electrode assembly is in the unexpanded configuration when the support is contracted.

24. The electrode assembly has a shell that isolates it from other electrode assemblies; The bioelectrochemical wastewater treatment system according to any one of claims 1 to 23, wherein the shell comprises an elastic rod wound around the electrode modules of the electrode assembly.

25. an actuator (18, 19) for controlling the flow rate of wastewater flowing into the wastewater treatment tank (2) and / or the flow rate of wastewater flowing out of the wastewater treatment tank (2); a controller (100) operably connected to the actuator for controlling the flow rate; The bioelectrochemical wastewater treatment system of any one of claims 1 to 24, further comprising:

26. sensors (102, 103, 104) communicatively connected to the controller (100); 26. The bioelectrochemical wastewater treatment system of claim 25, wherein the controller (100) receives signals from the sensors indicative of properties of materials treated by the system (1) and adjusts the actuators in response.

27. The controller (100) has a communication module for connecting to a remote server (210) via a network (200); The controller (100) communicates status data to the remote server (210) and receives configuration data transmitted from the remote server (210) in response to the communication; 27. The bioelectrochemical wastewater treatment system of claim 26, wherein the configuration data includes data for operating the controller (100) to control the actuators (18, 19) in response to signals received from the sensors.

28. An electrode assembly (4) configured to be submerged in a wastewater treatment tank (2) for use in a wastewater treatment system (1), comprising: a series of interconnectable electrode modules (5); Each of the electrode modules (5) comprises: a first electrode (51) consisting of an anode and cathode pair coated with electrogenic microorganisms adapted to generate electrons through consumption of organic matter in wastewater; a second electrode (52) consisting of an anode and a cathode pair; a body (50) supporting and separating the first electrode and the second electrode; an interface (53) for physically connecting the electrode module with at least one other electrode module, the interface being configured to electrically connect the first electrode and the second electrode of the electrode module with the first electrode and the second electrode of each of the other electrode modules, the interface having a readily detachable coupling member for coupling with a complementary coupling member of the other electrode module; An electrode assembly comprising:

29. 1. A bioelectrochemical wastewater treatment method comprising: providing an electrode assembly having a series of interconnectable electrode modules; Each of the electrode modules (5) comprises: a first electrode (51) consisting of an anode and cathode pair coated with electrogenic microorganisms adapted to generate electrons through consumption of organic matter in wastewater; a second electrode (52) consisting of an anode and a cathode pair; a body (50) supporting and separating the first electrode and the second electrode; an interface (53) for physically connecting the electrode module with at least one other electrode module, the interface being configured to electrically connect the first electrode and the second electrode of the electrode module with the first electrode and the second electrode of each of the other electrode modules, the interface having a readily detachable coupling member for coupling with a complementary coupling member of the other electrode module; and a wastewater treatment tank having a wastewater intake and a treated water outlet, the electrode assembly being submerged between the intake and the outlet; The electrodes of the series of electrode modules are electrically connected to an external power source or load via a circuit.

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