GB2613533A

GB2613533A - Electrocoagulation system

Info

Publication number: GB2613533A
Application number: GB2114803.6A
Authority: GB
Inventors: Bostock John; Tito Duarte
Original assignee: Aguahold Ltd
Current assignee: Aguahold Ltd
Priority date: 2021-10-15
Filing date: 2021-10-15
Publication date: 2023-06-14
Also published as: GB202114803D0; WO2023062388A1

Abstract

An electrode array 800 for an electrocoagulation reactor comprises a first plurality of electrodes 801; a second plurality of electrodes 803 electrically isolated from the first plurality of electrodes; a first electrode connector 807 electrically connected to each electrode of the first plurality of electrodes; a second electrode connector 805 electrically connected to each electrode of the second plurality of electrodes; a first sealing member between first and second electrodes of the first plurality of electrodes and surrounding the first electrode connector; and a second sealing member between first and second electrodes of the second plurality of electrodes and surrounding the second electrode connector. A method of monitoring an electrode array in an electrocoagulation reactor comprises: measuring an electrical parameter associated with providing current to the electrode array; comparing the measured electrical parameter with a predetermined value; and performing an electrode condition-dependent operation based on the comparison, wherein the electrical parameter may be the total charge passed by the electrode array, or a potential difference applied to the electrode array, or the rate of change of a potential difference applied to the electrode array. An electrocoagulation reactor module and a modular electrocoagulation system are also claimed.

Description

Electrocoagulafion system The present disclosure relates to an electrode array, an electrocoagulation reactor, an electrocoagulation reactor module, a modular electrocoagulation system, an electrocoagulation system with hydrogen recovery and a method of monitoring the condition of an electrode array in an electrocoagulation reactor.

Background

Coagulation is an ubiquitous process in wastewater treatment plants across the globe. The process objective is to capture (dissolved or suspended) contaminants in a waste stream and render its physical removal from the liquid phase (water) possible and/or efficient. Coagulation has two outputs: 1. Treated water-water from which contaminants have been removed.

2. Effluent sludge -solid sludge formed by the contaminants removed from solution.

Coagulation is effected by the addition of a coagulation agent (typically aluminium or iron) which, once in solution, forms insoluble compounds (aluminium hydroxide or iron hydroxide) that bind to contaminants and aggregate (coagulate) into macroscopic particles. These macroscopic particles (the floc) can then be physically removed from the liquid phase in a multitude of ways (e.g. settlement, flotation, filtration).

Using conventional chemical coagulation, the addition of aluminium or iron is carried out via dosing of soluble metal salts (e.g. aluminium sulphate or iron chloride) into the effluent stream via dosing stations. A key aspect of the logistics of chemical coagulation is the need to transport and store large volumes of corrosive chemicals and its associated health and safety infrastructure.

An alternative to chemical coagulation is electro-coagulation (EC). The fundamental principles of contaminant removal in EC are the same as in chemical coagulation; the difference lies in the mechanism of sourcing the coagulation agent. While in chemical coagulation this is achieved via dosing a reagent (a soluble metal salt, e.g. ferric chloride) into the effluent stream, in EC this is carried out by controlled corrosion of metallic plates (electrodes), typically of aluminium or steel. The rate of corrosion (which equates to the amount of metaVcoagulant dosed into solution), may be controlled by adjusting the current provided to the EC reactors.

The process is carried out by circulating effluent through the EC reactors whilst these are 'energised'. By controlling the effluent flow rate and current intensity, the treatment intensity (the dosing rate) is controlled. The plate material is spent as part of the process, 5 and consequently the reactors have a finite lifetime.

Typically, an EC reactor (also known as an EC cell) consists of an array of rectangular flat plates (electrodes) arranged parallel to each other. Two approaches to the configuration of the electrical connections to the EC reactor exist: monopolar and bipolar. These differ in the way that the electrodes are wired. In a monopolar configuration, all electrodes are physically connected to a power source and arranged in two groups: positive and negative. Each electrode is either positive or negative at any given time. In a bipolar cell configuration, only the outer electrodes on the array are physically connected to the power supply. The inner electrodes are polarised indirectly and hence each electrode has both opposing polarities (positive and negative).

Summary

This summary introduces concepts that are described in more detail in the detailed 20 description. It should not be used to identify essential features of the claimed subject matter, nor to limit the scope of the claimed subject matter.

In one aspect, an electrode array for an electrocoagulafion reactor comprises: a first plurality of electrodes; a second plurality of electrodes electrically isolated from the first plurality of electrodes; a first electrode connector electrically connected to each electrode of the first plurality of electrodes; a second electrode connector electrically connected to each electrode of the second plurality of electrodes; a first sealing member between first and second electrodes of the first plurality of electrodes and surrounding the first electrode connector; and a second sealing member between first and second electrodes of the second plurality of electrodes and surrounding the second electrode connector.

Optionally, each electrode connector comprises a plurality of (conducting) intermediate portions, each intermediate portion being positioned and providing an electrical connection between electrodes of the respective plurality of electrodes, and each electrode connector may comprise a main shaft passing through holes in the respective plurality of intermediate portions and passing through holes in the respective plurality of electrodes, optionally wherein each main shaft electrically connects the respective plurality of intermediate portions. First and second ends of each main shaft may be threaded, and each corresponding electrode connector may further comprise a first end nut connected to the first end of the main shaft and a second end nut connected to the second end of the main shaft, wherein the corresponding plurality of electrodes and plurality of intermediate portions are pressed together by the first end nut and the second end nut.

Each electrode connector may further comprise an external connection nut connected to the corresponding main shaft and configured to mate with an external connection shaft, 10 optionally wherein each external connection nut is one of the first end nuts, where each electrode connector may further comprise the external connection shaft.

Each sealing member may comprise a plurality of sealing member portions, each sealing member portion being positioned between electrodes of the respective plurality of electrodes and/or may comprise a plurality of 0-rings, each 0-ring configured to provide a seal between one of the first and second sealing members and the respective electrode connector. Each sealing member may be configured to provide a seal between respective first and second electrodes of the first or second plurality of electrodes and the respective electrode connector. Each sealing member may comprise a first and/or second sealing member end portion configured to seal an end of the respective electrode connector, optionally wherein the first sleeve end portion is configured to provide a seal between the respective electrode connector and a housing for receiving the electrode array.

The array may further comprise a plurality of electrode spacers, each electrode spacer being positioned between two electrodes of the first or second plurality of electrodes, and optionally wherein each electrode spacer is attached to an edge of an electrode of the first or second plurality of electrodes. Each electrode of the first and second plurality of electrodes may be uniformly spaced apart from adjacent electrodes of the first and second plurality of electrodes.

Each electrode connector may be made of a base metal such as brass, aluminium or copper. A base metal may be known as a non-noble metal or may be a metal that is not resistant to corrosion. The first and second pluralities of electrodes may comprise aluminium or iron.

In another aspect, an electrocoagulation reactor comprises: a first housing portion; a second housing portion connected to the first housing portion: a reactor inlet in the first housing portion and comprising a first reversable connector; a reactor outlet in the second housing portion and comprising a second reversable connector; a flow path between the reactor inlet and the reactor outlet, wherein the flow path is configured to receive an electrode array; and a first electrode array port and a second electrode array port in the first housing portion or the second housing portion.

The flow path is a path for fluid or effluent to be proceed by the reactor. The electrode array ports (e.g. access holes, through holes or connection holes) allow electrical connections to or from an electrode array to pass through the housing. The housing portions may be cylindrical and ensure that the majority/totality of the flow through the housing circulates through an electrode array housed therein. The housing may further comprise an electrode array housing for receiving an electrode array, wherein the electrode array housing has a square cross section. Reversible connectors for the reactor inlet and outlet are discussed in further detail below. Each reversible connector may be configured to connect to a complimentary reversible connector, and optionally wherein each reversible connector comprises a union nut, a threaded region, a screw connection or fitting, bayonet mount or fitting, clip fitting, lockable fitting or connector, clamp connector, or latch connecter.

The electrocoagulation reactor may comprise the electrode array, and optionally further comprise: a first sealing member between a first electrode connector of the electrode array and the first electrode array port; and a second sealing member between a second electrode connector of the electrode array and the second electrode array port. Optionally, the electrode array comprises a plurality of sacrificial electrodes and/or comprises aluminium or iron electrodes.

The reactor may further comprise a sealing member between the first housing portion and the second housing portion. When the first housing portion is disconnected from the second housing portion, an electrode array may be inserted into the flow path. The reactor may further comprise a long-nut configured to screw onto a connection shaft connected to the electrode pack, wherein when the long-nut is tightened, the electrode pack is pulled towards an inner wall of the reactor.

The electrode array may be any electrode array as described above and/or may be 35 configured to be operated in a monopolar configuration.

In another aspect, an electrocoagulation system comprises an electrocoagulation reactor as described above.

In another aspect, an electrocoagulation reactor module comprises: an electrocoagulation reactor comprising a reactor inlet and a reactor outlet; a module inlet configured to admit fluid into the electrocoagulation reactor module; a module outlet configured to discharge fluid from the electrocoagulation reactor module; a first conduit connecting the module inlet to the reactor inlet; and a second conduit connecting the reactor outlet to the module outlet. The module inlet and the module outlet may each comprise a reversible connector, optionally wherein each reversible connector is configured to connect to a complimentary reversible connector, and further optionally wherein each reversible connector comprises a union nut, a threaded region, a screw connection or fitting, bayonet mount or fitting, clip fitting, lockable fitting or connector, clamp connector, or latch connecter.

The electrocoagulation reactor may comprise an electrode array between the reactor inlet and the reactor outlet. The electrode array may comprise a plurality of sacrificial electrodes and/or comprise a plurality of aluminium or iron electrodes. The electrocoagulation reactor may comprise an electrode array as described above. The electrocoagulation reactor may be an electrocoagulation reactor as described above. The reactor module may comprise a frame, wherein the electrocoagulation reactor, first conduit and second conduit are located within the frame, optionally wherein the frame is an exterior frame. A frame can be, for example, a box or case and is configured to support and/or contain the components of the module.

The reactor module may comprise a valve in the first conduit and/or second conduit, the valve being configured to selectively isolate the electrocoagulation reactor from the module inlet and/or module outlet. The reactor module may also comprise a further electrocoagulation reactor, wherein the first conduit connects the module inlet to an inlet of the further electrocoagulation reactor, and wherein the second conduit connects the module outlet to an outlet of the further electrocoagulation reactor. There may be a plurality of valves in the first conduit and/or second conduit, the plurality of valves being configured to selectively isolate the further electrocoagulation reactor from the module inlet and/or module outlet.

The reactor module may further comprise: a lower manifold outlet; a lower manifold configured to connect the module inlet, lower manifold outlet and reactor inlet; an upper manifold inlet; and an upper manifold configured to connect the module outlet, upper manifold inlet and reactor outlet. The module inlet may be a lower manifold inlet and the module outlet may be an upper manifold outlet. When the module comprises a further reactor, this is also connected to the manifold in parallel with the first reactor.

In another aspect, a first electrocoagulation reactor module as described above and a second electrocoagulation reactor with upper and lower manifolds as described above is configured such that the module inlet of the first electrocoagulation reactor is connected to the lower manifold outlet of the second electrocoagulation reactor and the module outlet of the first electrocoagulation reactor is connected to the upper manifold inlet of the second electrocoagulation reactor.

In another aspect, a connector for connecting an electrocoagulation reactor module, as described above, to a second module, is provided.

In another aspect, a modular electrocoagulation system comprises: an electrocoagulation reactor module comprising: a reactor module inlet configured to admit fluid into the electrocoagulation reactor module; and a reactor module outlet configured to discharge fluid from the electrocoagulation reactor module; an auxiliary module comprising: an auxiliary module inlet configured to admit fluid into the auxiliary module; and an auxiliary module outlet configured to discharge fluid from the auxiliary module, wherein the reactor module inlet is connected to the auxiliary module outlet, or the reactor module outlet is connected to the auxiliary module inlet. An electrocoagulation system is a system for adding a coagulation agent to a fluid or effluent stream, and a reactor module is the part of the system that generates the coagulation agent electrochemically. The benefit of such a modular system is that plant expansion is straightforward and does not require bespoke fabrication of specific elements or software adaptation.

Optionally, each of the inlets and outlets comprises a reveisable connector, optionally 30 wherein the reversible connector comprises a union nut, a threaded region, a screw connection or fitting, bayonet mount or fitting, clip fitting, lockable fitting or connector, clamp connector, or latch connecter.

The electrocoagulation reactor module may be an electrocoagulation reactor module as 35 described above. The auxiliary module may be one of: a process module comprising a pump configured to circulate fluid in the system; a mixing module configured to receive fluid from the reactor module and agitate, mix or circulate the fluid e.g. with air; and a filtration module configured to concentrate or remove coagulated particles from a fluid. The mixing module may comprise a holding tank configured to receive the fluid and a recirculation pump configured to recirculate the fluid in the holding tank.

The electrocoagulation reactor module may further comprise one or more further auxiliary modules each connected to each other and the electrocoagulation reactor module, wherein each of the further auxiliary modules is one of a process module comprising a pump configured to circulate fluid in the system; a mixing module configured to receive fluid from the reactor module and agitate the fluid; and a filtration module configured to concentrate or remove coagulated particles from a fluid. A filtration module may comprise: a membrane rig; a mesh filter; a settling tank; and/or a skimmer.

The electrocoagulation reactor module may further comprise a control module electrically connected to the electrocoagulation reactor module and configured to control the electrocoagulation reactor module and auxiliary module. Each module may comprise a control panel configured to control the respective module, optionally wherein power and/or data connections are provided between each control panel. The control module may comprise a central control panel configured to control the control panels of the other modules. Each module may comprise a frame configured to encompass the respective module, optionally wherein the frame is an exterior frame. Each frame may be mounted on wheels or otherwise be configured to be mobile/make the respective module mobile. Each module is a component of the modular electrocoagulation system. The inlet/outlet of each module may be fluid or effluent inlet/outlet.

In another aspect, an electrocoagulation system comprises: an electrocoagulation reactor configured to electrochemically dose effluent with a coagulation agent, wherein dosing generates hydrogen gas as a by-product; and a hydrogen recovery apparatus connected to the electrocoagulation reactor and configured to recover the hydrogen gas. The hydrogen recovery apparatus may be a compressor, a cryogenic distillation apparatus, a pressure swing absorption apparatus, an electrochemical separation apparatus or a membrane separation apparatus, or the hydrogen recovery apparatus may be a fuel cell configured to use the hydrogen gas to generate electricity. Optionally, the electrocoagulation system further comprises a conduit between the electrocoagulation reactor and the hydrogen recovery apparatus, wherein the conduit is configured to transport the hydrogen gas from the electrocoagulation reactor to the hydrogen recovery apparatus. The hydrogen gas may be transported from the electrocoagulation reactor to the hydrogen recovery apparatus in the effluent or without the effluent. The hydrogen recovery apparatus may be a modular hydrogen recovery apparatus.

The electrocoagulation reactor may comprise an electrode array, and optionally the electrode array comprises a plurality of sacrificial electrodes and/or the electrode array comprises iron or aluminium electrodes. The electrode array may be an electrode array as described above. The electrocoagulation reactor may be an electrocoagulation reactor as described above.

In another aspect, a method of operating an electrocoagulation system comprises: reducing water into hydrogen in an electrocoagulation reactor; and recovering the hydrogen at a hydrogen recovery apparatus. The electrocoagulation system may be an electrocoagulation system as described above.

In another aspect, a method of monitoring the condition of an electrode array in an electrocoagulation reactor comprises: providing the electrode array with a current; measuring an electrical parameter associated with providing the current; comparing the measured electrical parameter with a predetermined value; and performing an electrode condition-dependent operation based on the comparison. The electrical parameter may be the total charge passed by the electrode array and the predetermined value a predetermined charge value, or the electrical parameter may be a potential difference applied to the electrode array and the predetermined value a predetermined potential difference value. The electrical parameter may also be the rate of change of a potential difference applied to the electrode array and the predetermined value a predetermined rate of change value.

The predetermined value may be a limit or threshold, and the electrode condition dependent operation may be performed if the measured electrical parameter is below the predetermined limit or threshold. Comparing the measured electrical parameter with a predetermined value may comprise determining that the electrical parameter is above a predetermined value or does not exceed a predetermined value. The electrode array may comprise sacrificial electrodes that are oxidised during operation, optionally wherein the sacrificial electrodes comprise iron or aluminium. The current may be a constant current.

The electrode condition dependent operation may comprise: determining that the electrode array needs to be replaced; generating a warning message; triggering an alarm; initiating cleaning of the electrode array; or disabling the electrode array. The electrode array may be configured to operate in a unipolar configuration. Advantageously, the electrode array may then degrade more evenly, increasing the reliability of the need to perform the electrode condition dependent operation.

In another aspect, an electrocoagulation system comprises: an electrocoagulation reactor comprising an electrode array; a current source connected to the electrode array; a measurement device configured to measure an electrical parameter associated with operating the current source; a processor; and a computer-readable medium comprising instructions which, when executed by the processor, causes the processor to perform a method as described above. The measurement device may comprise a voltmeter, ammeter, current integrator, current sensor and/or programmable logic controller. The current source may be a constant current source.

In another aspect, a computer-readable medium is provided, wherein the computer-readable medium comprises instructions which, when executed by a processor, causes the processor to perform a method as described above.

Brief Description of the Drawings

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates a modular electrocoagulation (EC) system 100; Figure 2 illustrates a control module 200; Figures 3a-c illustrate an EC module 300; Figures 4a-d illustrate a process module 400; Figures 5a-d illustrate a mixing module 500; Figures 6a-d illustrate a membrane module 600; Figures 7a and 7b illustrate block diagrams of a modular EC system 100; Figures 8a-k illustrate an electrode array 800 and components of the electrode array 800; Figure 9a-e illustrate an EC reactor 303; Figures 10a and 10b are block diagrams of a electrocoagulation system 1000 with hydrogen recovery apparatus 1001; Figure 11 is a flow diagram of a method of operating an electrocoagulation system 1000; Figure 12 is a flow diagram of a method of monitoring the condition of an electrode array 800; and Figure 13 is a block diagram of an electrode monitoring system 1300.

Detailed Description

Figure 1 illustrates a modular electrocoagulafion (EC) system 100. In the system 100, components for performing discrete electrocoagulafion steps have been 'encapsulated' into modular units, each modular unit performing a specific role in the system 100. The system 100 comprises a control module 200, an EC module 300, a process module 400, a mixing module 500 and a membrane module 600. The control module 200, EC module 300, process module 400, mixing module 500 and membrane module 600 are each shown individually in Figures 2, 3, 4, 5 and 6, respectively. The core module is the EC module 400 which is configured to add a coagulation agent to an effluent stream. The term effluent or effluent stream should be understood to comprise any kind of aqueous solution or mixture to be purified by the modular EC system 100. The other modules 100, 200, 400, 500 may be connected to the EC module 300 as necessary, depending on the specific requirements of a given system 100. Thus, the other modules 100, 200, 400, 500 may be termed auxiliary modules. The system 100 is not limited to comprising the above described modules and it is envisaged that other modules may be added to the system 100.

Each module comprises a control panel 201, 301, 401, 501, 601. Each control panel 201, 301, 401, 501, 601 is terminated with sets of plugin sockets at the base/bottom. Cables terminated with reciprocating quick-release plugs connect to the base of the panels and 'daisy-chain' the control panels such that mains power is distributed across the panels and therefore between each module and the control module 200. The plugs are 'off-the-shelf connectors that are secured to their respective sockets by a latch mechanism.

Figure 2 illustrates the control module 200. The control module 200 is the central control unit of the system 100 that communicates with each individual module 300, 400, 500, 600 and manages the system 100 as a whole. From the central control panel 201, a user can interface with the system 100 using a front end touch screen (not shown) and change parameters, start and stop operations and retrieve information. This can also be done remotely via a wireless connection. Plant management code executed by a plant computer (not shown) in the central control panel 201 carries out operations in specific sequences and timings that can be setup by an operator/system administrator. The functions it performs are within the standard remit of process control and the corresponding code may be developed using commercially available software. The control module 200 also comprises a DC rectifier 203. This is the power unit that provides DC power to the EC reactors 303, 305 of the EC module 300 when in operation.

The control module 200 comprises an exterior frame 205. All of the components of the control module i.e. the central control panel 201 and DC rectifier 203 are contained within the exterior frame 205, which defines the boundaries and exterior dimensions of the module 200 and enables to module 200 to be readily transported and installed. The frame may also be known as or be part of a box or container.

Figure 3a illustrates the EC module 300. The EC module 300 receives effluent (from the process module 400 in the present embodiment), adds coagulation agent to the effluent and then ejects the effluent with coagulation agent, passing it to the next module (which in the present embodiment is the mixing module 500). Local control panel 301 is configured to control the components of the EC module 300. The EC module 300 houses first and second EC reactors 303, 305. The EC reactors 303, 305 comprise aluminium electrodes which are an electrochemical source of coagulation agent. Other metals may be used for the electrodes, such as iron/steel. As discussed in further detail below, the EC reactors 303, 305 are made to be 'plug and play'. The contents of the EC reactors 303, 305 are consumable items and require regular replacement. The EC module 300 design and EC reactor 303, 305 design enable efficient operation of the system 100, for example by reducing downtime during routine maintenance or EC reactor replacement. As explained above, the EC reactors 303, 305 receive DC power from the DC rectifier 203 of the control module 200. Figure 3b illustrates the EC module 300 with no EC reactor installed, one EC reactor 303 installed and two EC reactors 303, 305 installed. While the exemplary EC reactor 303 with electrode array 800 described below is preferred, any suitable EC reactor may be used in the EC module 300. The module may also be configured to operate with only one EC reactor or more than two EC reactors i.e. it is not limited to the configuration of Figure 3a The EC module 300 further comprises a lower manifold inlet 307 (i.e. a fluid or hydraulic inlet) for receiving effluent (from the first process outlet 489 of process module 400, in the present case) and an upper manifold outlet 309 (i.e. a fluid or hydraulic outlet) for ejecting effluent comprising coagulation agent (back to process module 400 via second process inlet 479, in the present case). The lower manifold inlet 307 is connected to a lower manifold outlet 308 via a lower manifold 306. The upper manifold outlet 309 is connected to an upper manifold inlet 310 via an upper manifold 312. The upper and lower manifold inlets and outlets 307, 308, 309, 310 are terminated with reversible plug and play connecters, as discussed below. This allows additional EC modules 300 to be readily added to the system 100 to expand the capacity of the system 100. That is, in an expanded configuration, the lower manifold outlet 308 the EC module 300 can be connected to the lower manifold inlet 307 of a second EC module 300 (not shown). In accordance with the following discussion, effluent entering the first and second EC modules 300 passes into the lower manifolds 306, passes up through the EC reactors 303, 305 of each respective EC module 300 and into the respective upper manifolds 312. Effluent entering the upper manifold 312 of the second EC module 300 then exits the respective upper manifold 312 via the respective upper manifold outlet 309 and enters the upper manifold 312 of the first EC module 300 via the respective upper manifold inlet 310. In this manner, any number of EC modules 300 can be connected or chained together, as required. As would be understood, the upper manifold inlet 310 and lower manifold outlet 308 of the end EC module 300 of the chain of EC modules 300 are each sealed with a cap. Similarly, if only one EC module 300 is required, then the upper manifold inlet 310 and lower manifold outlet 308 are sealed, or the EC module 300 may be provided without an upper manifold inlet 310 and lower manifold outlet 308.

Returning to the description of a single EC module 300, drain valves 311 can be used to drain fluid/effluent from the EC module 300. Manual isolation values 333 enable each EC reactor 303, 305 to be hydraulically isolated such that they can be readily and safely removed and replaced without needing to shutoff the inlet 307. These are installed for safety/redundancy and effectively serve the same purpose as automated valves 313. Automated valves 313 open/close flow to a respective EC reactor 303, 305 during normal/automated operation as determined by the control software. That is, automated valves 313 control flow between the lower manifold 306 and the EC reactors 303, 305. A first conduit 319 connects the fluid inlet 307 to a reactor inlet 323 of the first EC reactor 303 (via the lower manifold 306) and a second conduit 321 connects the upper manifold outlet 309 to a reactor outlet 325 of the first EC reactor 303 (via the upper manifold 312). Analogous further conduits, inlets and outlets fiuidically connect the second EC reactor 305 in parallel with the first EC reactor 303. The EC module 300 also comprises a frame 315 and wheels 317 that provide a similar function to those of the control module 200.

The EC module 300 comprises the following advantageous features: * 'Plug and play' -both inlet and outlet 307, 309 and electronic connections to other modules are made via plug points so installation and/or expansion requires minimal effort. 'Plug and play' type connections, also known as reversible connections, for fluid conduits include but are not limited to: a union nut, a threaded region, a screw connection or fitting, bayonet mount or fitting, clip fitting, lockable fitting or connector, clamp connector, latch connecter and Camlock connector. Camlock connectors are readily available connectors, comprising either a male or female connector, where a lever mechanism on one part is configured to lock the complementary part in place. These connections may be used between the respective inlets and outlets of all modules. The module inlets and outlets are not necessarily directly connected to each other, for example, intermediate pipework may be inserted between the plug and play connections.

* Plug and play EC reactors 303, 305 -the EC reactors 303, 305 are connected hydraulically and electrically via simple and secure connections, as described in further detail below, to enable quick exchange of reactors during maintenance tasks.

* Valve arrangement 311, 313 -this is such that the plant can remain in operation whilst reactors are being replaced.

* Polarity reversal (1) -because the electrode packs in the EC reactors 303, 305 are connected in a monopolar configuration, at any given time half of the electrodes are positively polarised and the other half negatively polarised. By regularly reversing the polarity of the electrodes, the whole electrode pack can be used up evenly (which increases the lifetime of the pack).

* Polarity reversal (2) -polarity reversal also provides an electrode cleaning effect through the displacement of particulate matter settled on the electrode surface (hydrogen bubbles generated at the negatively polarised electrode physically displace particles and other surface contamination).

Figures 4a-c illustrate the process module 400. The process module 400 houses equipment required to perform basic process functions such as local control panel 401 configured to control the components of the process module 400, air compressor 403 for providing compressed air for automated valve operation and process pump 405 for supplying/circulating effluent in the system 100. Figure 4d illustrates the process module 400 without air compressor 403 in place. Effluent enters the system via first process inlet 499 and is pressurised via pump 405. If suitably pressurised effluent is available, pump 405 is not required. Pressurised effluent then leaves the process module 400 via first process outlet 489 and returns from an adjacent module (in this case EC module 300) to the process module 400 via second process inlet 479 and exits to an adjacent module (in this case mixing module 500) via second process outlet 469. Sensors for measurement of various process variables are included in the process module 400. These include a pH sensor 467, conductivity sensor 466, temperature sensor 468, pressure sensor 465 and flow sensors 464, 469. The process variables are transmitted to the central control panel 201 where they are used to monitor system performance and initiate any process adjustments, if needed. The individual components of the process module are standard 5 components, although the way they are grouped as a self-contained unit is unique. Grouping the particular array of equipment/instrumentation into the module means it encompasses all the necessary functionality in a compact footprint. Like the other modules, 'plug-and-play' hydraulic and electrical connections allow for the module to be installed in various combinations of system modules without alteration of the design. The 10 process module 400 also comprises a frame 409 and wheels 411 that provide a similar function to those of the control module 200 and EC module 300.

Figures 5a-d illustrate the mixing module 500. This module collects the output from the EC reactor module 300 (i.e. the dosed effluent stream) and homogenises it to maximise the use of the dosed coagulant. Control panel 501 controls the individual components of the mixing module 500 (in this case, mixing pump 507 and automated valve 599). The dosed effluent enters via fluid input 503. It then passes into a holding tank 505. The dosed effluent is recirculated within holding tank 505 using a recirculation pump 507. The dosed effluent exits the mixing module 500 via a fluid outlet 509 and enters the membrane module 600. The mixing module 500 also comprises a frame 511 and wheels 513, that provide a similar function to those of the control module 200, EC module 300 and process module 400.

Figures 6a-d, illustrate the membrane module 600. The membrane module 600 separates liquid of the effluent from precipitated particulate matter. At this stage, target contaminants in the effluent have bound to floc particles (e.g. comprising aluminium or iron) which are of greater size than the porosity of the filtering elements (the membranes) in the membrane module 600. In the membrane module 600, the particles are concentrated into a sludge whilst the liquid is discharged with a very low (or zero) solids load. The use of membranes differs from typical filtration in that it employs a 'cross-flow' filtration mechanism rather than the typical 'front-end' filtration, however the filtration technology itself is conventional and can be substituted for alternative filtration systems. Control panel 601 controls the individual components of the membrane module 600 i.e. a feed pump 628, recirculation pump 629, backpulse pump 627, automated valves 679 (for clean discharge), 678 (for backpulse) and 677 (for sludge discharge). Effluent enters the hydraulic (or fluid) input 603 of the membrane module 600 from the mixing module 500. The hydraulic input 603 comprises a holding tank configured to prevent pump 628 from running dry, although this is optional. A water level sensor 694 is provided in the holding tank of the hydraulic input 603 for this purpose. The membrane module 600 comprises a temperature sensor 695, pressure sensor 696, flow sensor 697, pH sensor 698 and conductivity sensor 699 for quality control purposes.

With reference to Figure 6d, arrows indicate the flow direction of effluent input (long dashes), permeate (i.e. clean water or treated effluent 103, alternating long/short dashes) and retentate (i.e. sludge or solids waste 105, short dashes).

The membrane module 600 also comprises a frame REF and wheels REF, that provide a similar function to those of the control module 200, EC module 300, process module 400 and mixing module 500.

Advantageous features of the membrane module are: * Modular membrane housings -these can be replaced and fitted with membrane elements of different porosities to meet particular process treatment targets.

* Hardware combination -the hardware included in the module (e.g. pumps, tanks and back-pulsing facility) is such that the module can function as a stand-alone unit.

The membrane module 600 is also a filtration module. Accordingly, the membrane module 600 may be replaced with different filtration modules. These different filtration modules provide a similar function to the membrane module i.e. they separate and/or concentrate coagulated contaminants from treated effluent. As such, they may comprise, for example, a mesh filter, settling tank, or skimmer.

Each of the above modules may be provided individually i.e. not as a complete or partial system. Furthermore, all of the above modules need not be provided together. For 30 example, only a selection of the above modules may be combined to provide an EC system 100.

Figure 7a is a block diagram of a modular EC system 100 comprising a reactor module 300 fluidically connected to a second (generic) module 700. A fluidic connection is a connection that enables the transfer of fluid from one module to the other, such as a pipe or conduit. Figure 7b is a block diagram corresponding to the system 100 of Figure 1. Figure 7b additionally shows an effluent source 101 that is fed into the system 100 and the two outputs of the system 100: treated effluent 103 and solids sludge 105. The system 100 of Figure 7b comprises a process module 400, an EC module 300, a mixing module 500 and a membrane module 600 fluidically connected in series. Effluent is fed into the process module 400 from the effluent source 101. It then passes from the process module 400 to the EC module 300, from the EC module 300 to the mixing module 500, and finally from the mixing module 500 to the membrane module 600, where it is processed before leaving the system 100 as treated effluent 103 and solids sludge 105. A control module 200 is in electrical communication with each of the other modules 300, 400, 500, 600 and controls and/or receives data from each of the other modules 300, 400, 500, 600.

Figure 8a-k illustrate an electrode array 800, also known as an electrode pack. During operation of an EC system or reactor comprising the electrode array 800, electrodes 801, 803 of the array 800 are consumed as they are electrically oxidised and release metal ions (the coagulation agent) into effluent. In an EC system or reactor, the electrode array 800 is analogous to the ink cartridge in a printer, since it is a consumable item that holds the 'active ingredient'.

The electrodes 801,803 are made of iron or aluminium (including steel and other alloys). The electrodes 801, 803 comprise a first plurality of electrodes 801 and a second plurality of electrodes 803. The constituent electrodes of the first plurality of electrodes 801 are held together and electrically connected to each other by a first electrode connector 805. The constituent electrodes of the second plurality of electrodes 803 are held together and electrically connected to each other by a second electrode connector 807. The first and second plurality of electrodes 801, 803 overlap and alternate with each other in an interdigitated configuration. This enables the electrode array 800 to be operated in a monopolar configuration, which can increase the utilisation of the electrodes, i.e. how much of each electrode is consumed before the electrode array 800 must be replaced, and also encourages uniform degradation of each electrode.

As illustrated in Figures 8c and 8d, in order to help retain the relative positions of the first and second plurality of electrodes 801, 803, spacers 813 are provided along edges of the electrodes 801, 803. Figure 8d illustrates a single spacer in cross-section. The spacers comprise U-shaped channels 815 and can be push fit onto the sides of the electrodes 801, 803. They are made of any suitable insulating material such as rubber or plastic. A locating bar 811 (made of brass in order to improve current distribution) passes through guide holes 809 in each of the electrodes 801, 803 in order to further stabilise the relative positions of the electrodes 801, 803 and facilitate assembly of the electrode array 800. As illustrated in Figure 8e, the electrode array 800 is housed in a plastic box section 816, to help maintain physical integrity and guide flow, which is open at the top and bottom such that effluent can enter and exit.

As stated above, the electrode array 800 requires regular replacement in an EC system as it has a finite lifetime determined by the amount of metal it holds. Consequently, the time required to assemble an electrode array 800 impacts significantly on its overall cost. Furthermore, the electrode connectors 805, 807 can be reused since they should not degrade in use, and so the spent electrode array may be disassembled in order to recover the electrode connectors 805, 807/reinstall new electrodes 801, 803. As such, the electrode connectors 805, 807 are constructed such that assembly/disassembly time is minimised.

The electrode connectors 805, 807 electrically connect the constituent electrodes of the first and second plurality of electrodes 801, 803. Crucially, any metal (or electrical conducting) components of the electrode connectors 805, 807 are sealed such that when the electrode assembly 800 is submerged in effluent, these metal components cannot be contacted by the effluent, to prevent them from being corroded during operation. The electrode connectors 805, 807 each comprise two distinct portions: a sleeve 817, 819, 821 and an electrical connection element 827, 829, 831, 833, 835, 837 surrounded by the respective sleeve 817, 819, 821. With reference to Figure 8f, each sleeve 817, 819, 821 comprises first and second sleeve end portions 817, 819 (also illustrated in Figures 8h and 8k) and a plurality of intermediate sleeve portions 821 (also illustrated in Figure 8g). The sleeve portions 817, 819, 821 are hollow. The sleeve portions 817, 819, 821 are made of plastic, but any suitable material that is impermeable to water and insulating may be used instead. As can be seen from Figures 8g and 8h, the inside of each sleeve portion 817, 819, 821 is recessed in order to accommodate an 0-ring 823. The first and second sleeve end portions 817, 819 are located on the outer sides of the first and last electrodes of each plurality of electrodes 801, 803. Between every two directly adjacent electrodes of each plurality of electrodes 801, 803 there is an intermediate sleeve portion 821. As can be seen more clearly in Figure 8k, different configurations of the second sleeve end portions 819 are possible. In one configuration, a second sleeve end portion 819 comprises an inner portion 824 and a terminating cap 825. The inner portion 824 comprises a lip and is configured to be screwed against an electrode when second end nut 833 (discussed in detail below) is tightened. An 0-ring 826a provides a seal between the corresponding electrode and the inner portion 824. The inner portion 824 is cylindrical and the inside of the inner portion 824 is threaded, while the terminating cap 825 comprises a corresponding threaded portion. As such, the terminating cap 825 is configured to screw into the inner portion 824, providing a seal around the corresponding end of the electrical connection element 827, 829, 831, 833, 835, 837. An 0-ring 826b between the inner portion 824 and a lip of the terminating cap 825 ensures a water-tight seal between these components.

In an alternative configuration, the second sleeve end portion 819 comprises a major cavity 818a and a minor cavity 818b extending from the major cavity 818a. The inside of the minor cavity 818b is threaded and configured to screw directly onto the threaded portion of the main shaft 827 of the corresponding electrical connection element 827, 829, 831, 833, 835, 837 (discussed in detail below). The major cavity 818a is configured to accommodate the second end nut 833 which is also screwed on the threaded portion of the main shaft 827. Thus, the second sleeve end portion 819 is configured to screw directly onto the end of an electrical connection element 827, 829, 831, 833, 835, 837 and form a seal against an electrode. An 0-ring 826 ensures that a water-tight seal is provided between the second sleeve end portion 819 and the corresponding electrode. While Figure 8k illustrates one of each of these configurations of the second sleeve end portions 819, the same type of second sleeve end portion 819 can be used for each sleeve portion 817, 819, 821.

Thus, the sleeve portions 817, 819, 821 provide a water-tight seal against each electrode 801, 803 and house the electrical connection element 827, 829, 831, 833, 835, 837 of the electrode connectors 803, 805. As can be seen from at least Figure 8k, the respective first and second sleeve end portions 817, 819 on each electrode connector 803, 805 may be different lengths to account for the interdigitated configuration of the electrodes and ensure that the ends of each electrode connector are aligned.

With reference to Figure 8j which illustrates the electrode connectors 805, 807 without the sleeves 817, 819, 821 and electrodes 801, 803, and Figure 8k which is a cross-section of the electrode connectors 805, 807 in a fully assembled electrode array 800, each electrical connection element 827, 829, 831, 833, 835, 837 of the electrode connectors 803, 805 comprises a main shaft 827. Each main shaft 827 passes through holes in each electrode of the plurality of electrodes 801, 803, each hole having a similar diameter to the diameter of each main shaft 827. Each main shaft 827 also passes through a plurality of annular intermediate portions 831. The main shaft provides an electrical connection between the respective plurality of electrodes 801, 803. Each intermediate portion 831 is positioned between two directly adjacent electrodes of each plurality of electrodes 801, 803 and comprises a hole through which the main shaft 827 passes. The intermediate portions 831 act as spacers between the electrodes 801, 803 and also provide a reliable low resistance electrical connection between the electrodes 801, 803 and each electrical connection element/electrode connector 803, 805.

In order to secure the electrodes 801, 803 and intermediate portions 831 together, each end of each main shaft 827 is threaded, and one end of each main shaft 827 is connected to a first electrical connection element end portion 829 (also known as a first end nut) and the opposing end is connected to a second electrical connection element end portion 833 (also known as a second end nut). As such, the first electrical connection element end portion 829 and second electrical connection element end portion 833 are annular and each comprise a corresponding internal threaded portion configured to mate with the corresponding threaded portions on each main shaft 827. When the end portions 829, 833 are screwed onto the corresponding main shaft 827, they press together the intervening plurality of electrodes 801, 803 and intermediate portions 831 and hold them in place, as well as promoting good electrical contact.

As can be seen from at least Figure 8k, the respective first electrical connection element end portions 829 and second electrical connection element end portions 833 on each electrode connector 805, 807 may be different lengths in order to align the ends of each electrode connector and accommodate for the offset interdigitated electrodes 801, 803. Furthermore, each first electrical connection element end portion 829 is connected to an external connection shaft 835. Each external connection shaft 835 enables each electrode connector 805, 807 to be connected to a power supply when part of an EC system such as the EC system 100 described above and also provides a connection through the housing of an EC reactor comprising the electrode array 800, such as the EC reactor 303 described above and below. Each external connection shaft 835 is threaded at each end. As such, one end screws into the internal threaded portion of one of the first electrical connection element end portions 829, where it abuts the corresponding main shaft 827.

Each end portions 829 comprises a flat section on the outside to enable its use as a nut and securely tighten the array of electrodes and spacers. The opposing end of the external connection shaft 835 is connected to an external connection shaft nut 837.

The electrically conductive components of each electrode connector 803, 805 i.e. the main shafts 827, end and intermediate portions 829, 831, 833, connection shafts 835 and external connection shaft nut 837 are made of brass, although any suitable metal could be used instead. Crucially, these components do not need to be electrochemically inert since they are shielded from effluent by the sleeve portions 817, 819, 821.

In operation, each electrode connector 805, 807 physically connect all the electrodes of one of the plurality of electrodes 801, 803 to the power/current source (i.e. in a monopolar configuration) whilst ensuring that all connections are dry despite being submerged. This is of significance because monopolar operation provides greater control over electrode pack usage e.g. packs can be used to >90% of their metal content.

An EC reactor 303 is illustrated in Figures 9a-c. As will become evident from the following discussion, the EC reactor 303 may be readily removed from an EC system or EC module, such as but not limited to the EC system 100 or EC module 300 disclosed above, and is also configured such that an electrode array, such as but not limited to an electrode array 800 as disclosed above, may be readily installed/replaced in the module.

A housing of the EC reactor 303 comprises a main housing or first housing portion 327 and a cap or second housing portion 329. The housing is configured to receive an electrode array 800. The main housing comprises a reactor inlet 323 comprising a first reversable connector configured to reversibly connect to a conduit in an EC system. The cap 329 comprises a reactor outlet 325 comprising a second reversable connector also configured to reversibly connect to a conduit in an EC system. Thus, the EC reactor 303 can be readily inserted into and removed from an EC system.

A sealing member (not illustrated) is provided between the housing portions 327, 329. The sealing member is a rubber gasket that is cut to shape to match the profile of the housing portions 327, 329. Bolts 328 pass through the housing portions 327, 329 and clamp the housing portions 327, 329 together. Thus, the EC reactor may be readily opened and closed to remove a spent electrode array 800 and insert a new one. The shape of the sealing member matches the profile of the respective ends of the housing portions 327, 329, i.e. it is square in the present example. The second housing portion 329 comprises first and second electrode array ports 331, 333. The electrode array ports 331, 333 allow electrical connectors of the electrode array to pass through the housing of the EC reactor 303.

Figures 9d and 9e illustrate a top-down view of EC reactor 303 with and without second housing portion 329. A completed electrode array 800 (terminated at first electrical connection element end portion 829) is dropped into the housing 327. Then an external connection shaft 835 is screwed into each first electrical connection element end portion 829. After that, an internally threaded long-nut 339 is screwed onto each external connection shaft 835. An 0-ring 341 at the end of each first electrical connection element end portion 829 provides a seal with the inner wall of the second housing portion 329.

Long-nut 339 (also known as a housing nut) abuts first electrical connection element end portion 829. Long-nut 339 has a similar internal diameter to the outer diameter of external connection shaft 835, which threads/screws into the corresponding long-nut 339. With reference to Figure 9e, removable cover 335 is attached to the second housing portion 329 using a cover T-nut 337 to protect the connection points (e.g. connection shafts 835 10 and external connection shaft nuts 837) for cables leading to a power supply.

The inventors have identified that there is an opportunity improve EC system energy efficiency by recovering the hydrogen which is generated as a by-product during dosing of the coagulation agent in an EC reactor. Ordinarily, this hydrogen is vented to the ambient atmosphere and lost. Figure 10a illustrates a block diagram of an EC system 1000 with hydrogen recovery apparatus 1001. The system 1000 comprises an EC reactor 303 configured to electrochemically dose effluent with a coagulation agent, wherein dosing generates hydrogen gas as a by-product; and a hydrogen recovery apparatus 1001 connected to the EC reactor 303 and configured to recover the hydrogen gas.

The hydrogen recovery apparatus 1001 is a compressor configured to capture and store the hydrogen in a storage vessel as pressurised hydrogen gas. Alternatively, the hydrogen storage apparatus may be a cryogenic distillation apparatus, a pressure swing absorption apparatus, an electrochemical separation apparatus or a membrane separation apparatus, all of which are known to the skilled person. Alternatively, the hydrogen recovery apparatus 1001 may be a fuel cell configured to use the hydrogen gas to generate electricity.

A conduit is provided between the EC reactor 303 and the hydrogen recovery apparatus 1001, wherein the conduit is configured to transport the hydrogen gas from the EC reactor to the hydrogen recovery apparatus. Specifically, the hydrogen gas is transported from the EC reactor 303 to the hydrogen recovery apparatus 1001 in the effluent, although in other embodiments, the hydrogen gas is transported from the EC reactor 303 to the hydrogen recovery apparatus 1001 without the effluent. The EC reactor 303 is in accordance with the electrocoagulation reactor 303 described above and illustrated in Figure 9c, although any suitable EC reactor may be used instead.

With reference to Figure 10b, in an embodiment, the EC system 1000 is the EC system 100 described above and illustrated in Figures 1 or 7b, with the addition of a hydrogen recovery apparatus 1001. In this case, the EC reactor 303 is provided in EC module 300. The hydrogen recovery apparatus 1001, which may be any of the above-described hydrogen recovery apparatuses 1001, is connected to the EC reactor 303 in the EC module via the mixing module 500. In detail, when dosed effluent 101 enters the holding tank 505 of the mixing module 500, the hydrogen gas present in the effluent 101 spontaneously diffuses out of the effluent and into a cavity at the top of the holding tank. From here it is pumped or travels spontaneously via a conduit to the hydrogen recovery apparatus 1001. As such, in contrast to the above-described holding tank 505, the holding tank 505 may be sealed at the top to prevent the hydrogen gas from escaping into the ambient atmosphere.

In other embodiments, the hydrogen recovery apparatus 1001 is plumbed into a closed loop in parallel with the EC reactor 303 or is placed in line between the EC reactor 303 and the mixing module 500. In these embodiments, the hydrogen recovery apparatus 1001 may be a fuel cell, such as a PEM fuel cell, configured to convert hydrogen in the effluent stream into electricity, without the need to separate or store the hydrogen gas. Alternatively, a membrane separation apparatus may be used to extract the hydrogen from the effluent.

With reference to the flow diagram of Figure 11, a method of operating an electrocoagulafion system 1000 comprises reducing 1101 water into hydrogen in an electrocoagulafion reactor 303; and recovering 1103 the hydrogen at a hydrogen recovery apparatus 1001. The electrocoagulafion system 1000 is an electrocoagulafion system 1000 as illustrated in Figure 10a or 10b.

Figure 12 is a flow diagram for a method 1000 of monitoring the condition of an electrode array 800 in an EC reactor 303. The EC reactor 303 and electrode array 800 are as described above, however, the method may be performed with any suitable EC reactor or electrode array. The method comprises providing 1201 the electrode array 800 with a current; measuring 1203 an electrical parameter associated with providing the current; comparing 1205 the measured electrical parameter with a predetermined value; and performing 1207 an electrode condition-dependent operation based on the comparison.

In one embodiment, the electrical parameter is the total charge passed by the electrode array 800 and the predetermined value is a predetermined charge threshold.

In other embodiments, the electrical parameter is a potential difference applied to the electrode array 800 or the rate of change of a potential difference applied to the electrode array 800, and the predetermined value is a predetermined potential difference threshold 5 or predetermined rate of change threshold, respectively.

The electrode condition dependent operation is performed if the measured electrical parameter is below the respective predetermined threshold and comprises determining that the electrode array needs to be replaced. Alternatively or additionally, the operation comprises generating a warning message; triggering an alarm; initiating cleaning of the electrode array; or disabling the electrode array. The electrode array 800 is configured to operate in a unipolar configuration. As such, the electrode array is expected to degrade/be consumed in a predictable manner. The inventors have identified that by monitoring the charge consumed by the electrode during operation, once the charge reaches a threshold, the charge value can be used to identify that the electrode array 800 needs replacing before system performance drops significantly. Alternatively, since the voltage required to pass a given current (e.g. to maintain a constant current) increases over time, by monitoring this voltage or rate of change of this voltage, the point at which it becomes necessary to replace the electrode array 800 can also be identified. These predetermined values can be determined by modelling behaviour of the system using standard electrochemical models based on Faraday's law, or they can be determined empirically. By way of example, a pack containing 36 kg of iron will hold a theoretical charge of 124,052,142 C. Once a predetermined value of 10% is remaining (i.e. 12,405,214 C) the pack can be regarded as 'spent and is replaced. Other uses of voltage monitoring include identifying anomalous operation if the voltage becomes unexpectedly high. As a result, a warning message can be sent to an operator, or the EC reactor 303 can be shut down in order to prevent damage to the EC reactor. Furthermore, a high voltage can be indicative of the need to initiate a cleaning cycle, thus ensuring optimum operation of an EC system e.g. if typical operational voltage for a given site is 5 V but this rapidly increases to a predetermined threshold value (e.g. 10 V) then a cleaning cycle can be triggered.

The described methods may be implemented using computer executable instructions. A computer program product or computer readable medium may comprise or store the computer executable instructions. The computer program product or computer readable medium may comprise a hard disk drive, a flash memory, a read-only memory (ROM), a CD, a DVD, a cache, a random-access memory (RAM) and/or any other storage media in which information is stored for any duration (e.g. for extended time periods, permanently, brief instances, for temporarily buffering, and/or for caching of the information). A computer program may comprise the computer executable instructions. The computer readable medium may be a tangible or non-transitory computer readable medium. The term "computer readable" encompasses "machine readable".

Also disclosed, and with reference to the block diagram of Figure 13, is an EC system 1300 configured to perform electrode array monitoring comprising: an electrocoagulation reactor 303 comprising an electrode array 800; a constant current source 1301 connected to the electrode array 800; a measurement device 1303 configured to measure an electrical parameter associated with operating the current source 1301; a processor 1305 configured to control the constant current source 1301 and receive the electrical parameter measurement from the measurement device 1303; and a computer-readable medium 1307 comprising instructions which, when executed by the processor, causes the processor to perform a method according to Figure 12. The EC system is as illustrated in Figure 1 and 7b, although the EC system may be any suitable system with the addition of the above-described electrode array monitoring apparatus. The measurement device comprises a voltmeter, ammeter, current integrator, current sensor and programmable logic controller.

Also disclosed is a computer-readable medium comprising instructions which, when executed by a processor, causes the processor to perform a method according to Figure 12.

The embodiments of the invention shown in the drawings and described above are exemplary embodiments only and are not intended to limit the scope of the appended claims, including any equivalents as included within the scope of the claims. Various modifications are possible and will be readily apparent to the skilled person in the art. It is intended that any combination of non-mutually exclusive features described herein are within the scope of the present invention. That is, features of the described embodiments can be combined with any appropriate aspect described above and optional features of any one aspect can be combined with any other appropriate aspect.

Claims

Claims 1. An electrode array for an electrocoagulation reactor comprising: a first plurality of electrodes; a second plurality of electrodes electrically isolated from the first plurality of electrodes; a first electrode connector electrically connected to each electrode of the first plurality of electrodes; a second electrode connector electrically connected to each electrode of the second plurality of electrodes; a first sealing member between first and second electrodes of the first plurality of electrodes and surrounding the first electrode connector; and a second sealing member between first and second electrodes of the second plurality of electrodes and surrounding the second electrode connector.
2. An electrode array for an electrocoagulation reactor according to claim 1, wherein each electrode connector comprises a plurality of intermediate portions, each intermediate portion being positioned and providing an electrical connection between electrodes of the respective plurality of electrodes.
3. An electrode array for an electrocoagulation reactor according to claim 2, wherein each electrode connector comprises a main shaft passing through holes in the respective plurality of intermediate portions and passing through holes in the respective plurality of electrodes, and optionally wherein each main shaft electrically connects the respective plurality of intermediate portions.
4. An electrode array for an electrocoagulation reactor according to claim 3, wherein first and second ends of each main shaft are threaded, and each corresponding electrode connector further comprises a first end nut connected to the first end of the main shaft and a second end nut connected to the second end of the main shaft, wherein the corresponding plurality of electrodes and plurality of intermediate portions are pressed together by the first end nut and the second end nut.
5. An electrode array for an electrocoagulation reactor according to claim 4, wherein each 35 electrode connector further comprises an external connection nut connected to the corresponding main shaft and configured to mate with an external connection shaft, and optionally wherein each external connection nut is one of the first end nuts, and further optionally further comprising the external connection shaft.
6. An electrode array for an electrocoagulation reactor according to any preceding claim, 5 wherein each sealing member comprises a plurality of sealing member portions, each sealing member portion being positioned between electrodes of the respective plurality of electrodes.
7. An electrode array for an electrocoagulation reactor according to any preceding claim, 10 further comprising a plurality of 0-rings, each 0-ring configured to provide a seal between one of the first and second sealing members and the respective electrode connector.
8. An electrode array for an electrocoagulation reactor according to any preceding claim, wherein each sealing member is configured to provide a seal between respective first and 15 second electrodes of the first or second plurality of electrodes and the respective electrode connector.
9. An electrode array for an electrocoagulation reactor according to any preceding claim, wherein each sealing member comprises a first and/or second sealing member end portion configured to seal an end of the respective electrode connector, optionally wherein the first sleeve end portion is configured to provide a seal between the respective electrode connector and a housing for receiving the electrode array.
10. An electrode array for an electrocoagulation reactor according to any preceding claim, further comprising a plurality of electrode spacers, each electrode spacer being positioned between two electrodes of the first or second plurality of electrodes, and optionally wherein each electrode spacer is attached to an edge of an electrode of the first or second plurality of electrodes.
11. An electrode array for an electrocoagulation reactor according to any preceding claim, wherein each electrode of the first and second plurality of electrodes is uniformly spaced apart from adjacent electrodes of the first and second plurality of electrodes
12. An electrode array for an electrocoagulation reactor according to any preceding claim, 35 wherein each electrode connector is made of a base metal, and optionally made of brass, aluminium or copper.
13. An electrode array for an electrocoagulation reactor according to any preceding claim, wherein the first and second pluralities of electrodes comprise aluminium or iron.
14. An electrocoagulation reactor, the reactor comprising: a first housing portion; a second housing portion connected to the first housing portion; a reactor inlet in the first housing portion and comprising a first reversable connector; a reactor outlet in the second housing portion and comprising a second reversable connector; a flow path between the reactor inlet and the reactor outlet, wherein the flow path is configured to receive an electrode array; and a first electrode array port and a second electrode array port in the first housing portion or the second housing portion
15. An electrocoagulation reactor according to claim 14, wherein each reversible connector is configured to connect to a complimentary reversible connector, and optionally wherein each reversible connector comprises a union nut, a threaded region, a screw connection or fitting, bayonet mount or fitting, clip fitting, lockable fitting or connector, clamp connector, or latch connecter.
16. An electrocoagulation reactor according to claim 14 or 15, further comprising the electrode array.
17. An electrocoagulation reactor according to claim 16, further comprising: a first sealing member between a first electrode connector of the electrode array and the first electrode array port; and a second sealing member between a second electrode connector of the electrode array and the second electrode array port.
18. An electrocoagulation reactor according to claims 16 or 17, wherein the electrode array comprises a plurality of sacrificial electrodes and/or comprises aluminium or iron electrodes.
19. An electrocoagulation reactor according to any of claims 14 to 18, wherein when the first housing portion is disconnected from the second housing portion, an electrode array may be inserted into the flow path.
20. An electrocoagulation reactor according to any of claims 14 to 19, wherein the electrode array is an electrode array according to any of claims 1 to 13.
21. An electrocoagulation reactor according to any of claims 16 to 20, further comprising a housing nut passing through the first or second electrode array port and connected to the electrode array, wherein when the housing nut is tightened, the electrode array is sealed against the housing.
22. An electrocoagulation reactor according to any of claims 14 to 21, wherein the electrode array is configured to be operated in a monopolar configuration.
23. An electrocoagulation system comprising an electrocoagulation reactor according to any of claims 14 to 22. 15
24. An electrocoagulation reactor module, the module comprising: an electrocoagulation reactor comprising a reactor inlet and a reactor outlet; a module inlet configured to admit fluid into the electrocoagulation reactor module; a module outlet configured to discharge fluid from the electrocoagulation reactor module; a first conduit connecting the module inlet to the reactor inlet; and a second conduit connecting the reactor outlet to the module outlet.
25. An electrocoagulation reactor module according to claim 24, wherein the module inlet and the module outlet each comprise a reversible connector, and optionally wherein each reversible connector is configured to connect to a complimentary reversible connector, and further optionally wherein each reversible connector comprises a union nut, a threaded region, a screw connection or fitting, bayonet mount or fitting, clip fitting, lockable fitting or connector, clamp connector, or latch connecter.
26. An electrocoagulation reactor module according to claim 24 or 25, wherein the electrocoagulation reactor comprises an electrode array between the reactor inlet and the reactor outlet.
27. An electrocoagulation reactor module according to claim 26, wherein the electrode array comprises a plurality of sacrificial electrodes and/or comprises a plurality of aluminium or iron electrodes.
28. An electrocoagulation reactor module according to claim 26 or 27, wherein the electrocoagulation reactor comprises an electrode array according to any of claims 1 to 13.S
29. An electrocoagulation reactor module according to any of claims 24 to 28, wherein the electrocoagulation reactor is an electrocoagulation reactor according to any of claims 14 to 23.
30. An electrocoagulation reactor module according to any of claims 24 to 29, further comprising a frame, wherein the electrocoagulation reactor, first conduit and second conduit are located within the frame, and optionally wherein the frame is an exterior frame.
31. An electrocoagulation reactor module according to any of claims 24 to 30, further 15 comprising a valve in the first conduit and/or second conduit, the valve being configured to selectively isolate the electrocoagulation reactor from the module inlet and/or module outlet.
32. An electrocoagulation reactor module according to any of claims 24 to 31, further 20 comprising a further electrocoagulation reactor, wherein the first conduit connects the module inlet to an inlet of the further electrocoagulation reactor, and wherein the second conduit connects the module outlet to an outlet of the further electrocoagulation reactor.
33. An electrocoagulation reactor module according to claim 32, further comprising a 25 plurality of valves in the first conduit and/or second conduit, the plurality of valves being configured to selectively isolate the further electrocoagulation reactor from the module inlet and/or module outlet.
34. An electrocoagulation reactor module according to any of claims 24 to 33, further comprising: a lower manifold outlet; a lower manifold configured to connect the module inlet, lower manifold outlet and reactor inlet; an upper manifold inlet; and an upper manifold configured to connect the module outlet, upper manifold inlet and reactor outlet.
35. A first electrocoagulation reactor module according to the electrocoagulation reactor module of any of claims 24 to 34 and a second electrocoagulation reactor module according to the electrocoagulation reactor module of claim 34, wherein the module inlet of the first electrocoagulation reactor is connected to the lower manifold outlet of the second electrocoagulation reactor and the module outlet of the first electrocoagulation reactor is connected to the upper manifold inlet of the second electrocoagulation reactor.
36. A connector for connecting an electrocoagulation reactor module according to any of claims 24 to 34 to a further module. 10
37. A modular electrocoagulation system, the system comprising: an electrocoagulation reactor module comprising: a reactor module inlet configured to admit fluid into the electrocoagulation reactor module; and a reactor module outlet configured to discharge fluid from the electrocoagulation reactor module; and an auxiliary module comprising: an auxiliary module inlet configured to admit fluid into the auxiliary module; and an auxiliary module outlet configured to discharge fluid from the auxiliary module, wherein the reactor module inlet is connected to the auxiliary module outlet, or the reactor module outlet is connected to the auxiliary module inlet.
38. A modular electrocoagulation system according to claim 37, wherein each of the inlets and outlets comprises a reversable connector, and optionally wherein the reversible connector comprises a union nut, a threaded region, a screw connection or fitting, bayonet mount or fitting, clip fitting, lockable fitting or connector, clamp connector, or latch connecter.
39. A modular electrocoagulation system according to claim 37 01 38. wherein the electrocoagulation reactor module is an electrocoagulation reactor module according to any of claims 24 to 34.
40. A modular electrocoagulation system according to any of claims 37 to 39, wherein the auxiliary module is one of: a process module comprising a pump configured to circulate fluid in the system; a mixing module configured to receive fluid from the reactor module and agitate the fluid; and a filtration module configured to concentrate or remove coagulated particles from a fluid
41. A modular electrocoagulation system according to claim 40, further comprising one or more further auxiliary modules each connected to each other and the electrocoagulation reactor module, wherein each of the further auxiliary modules is one of: a process module comprising a pump configured to circulate fluid in the system; a mixing module configured to receive fluid from the reactor module and agitate the fluid; and a filtration module configured to concentrate or remove coagulated particles from a fluid.
42. A modular electrocoagulation system according to claim 40 or 41, wherein the filtration module comprises: a membrane rig; a mesh filter; a settling tank; and/or a skimmer.
43. A modular electrocoagulation system according to any of claims 37 to 42, further comprising a control module electrically connected to the electrocoagulation reactor module and configured to control the electrocoagulation reactor module and auxiliary 25 module.
44. A modular electrocoagulation system according to any of claims 37 to 43, wherein each module comprises a control panel configured to control the respective module, and optionally wherein power and/or data connections are provided between each control 30 panel.
45. A modular electrocoagulation system according to claim 44, wherein, when dependent on claim 43, the control module comprises a central control panel configured to control the control panels of the other modules.
46. A modular electrocoagulation system according to any of claims 37 to 45, wherein each module comprises a frame configured to encompass the respective module, and optionally wherein the frame is an exterior frame.
47. A modular electrocoagulation system according to any of claims 37 to 46, wherein each module is a component of the modular electrocoagulation system.
48. An electrocoagulation system, the system comprising: an electrocoagulation reactor configured to electrochemically dose effluent with a 10 coagulation agent, wherein dosing generates hydrogen gas as a by-product; and a hydrogen recovery apparatus connected to the electrocoagulation reactor and configured to recover the hydrogen gas.
49. An electrocoagulation system according to claim 48, wherein the hydrogen recovery 15 apparatus is a compressor, a cryogenic distillation apparatus, a pressure swing absorption apparatus, an electrochemical separation apparatus or a membrane separation apparatus.
50. An electrocoagulation system according to claim 48 or 49, wherein the hydrogen 20 recovery apparatus is a fuel cell configured to use the hydrogen gas to generate electricity.
51. An electrocoagulation system according to any of claims 48 to 50, further comprising a conduit between the electrocoagulation reactor and the hydrogen recovery apparatus, 25 wherein the conduit is configured to transport the hydrogen gas from the electrocoagulation reactor to the hydrogen recovery apparatus.
52. An electrocoagulation system according to claim 51, wherein the hydrogen gas is transported from the electrocoagulation reactor to the hydrogen recovery apparatus in the 30 effluent or without the effluent.
53. An electrocoagulation system according to any of claims 48 to 52, wherein the hydrogen recovery apparatus is a modular hydrogen recovery apparatus.
54. An electrocoagulation system according to any of claims 48 to 53, wherein the electrocoagulation reactor comprises an electrode array, and optionally wherein the electrode array comprises a plurality of sacrificial electrodes and/or wherein the electrode array comprises iron or aluminium electrodes.
55. An electrocoagulation system according to any of claims 48 to 54, wherein the 5 electrode array is an electrode array according to any of claims 1 to 13.
56. An electrocoagulation system according to any of claims 48 to 55, wherein the electrocoagulation reactor is an electrocoagulation reactor according to any of claims 14 to 22.
57. A method of operating an electrocoagulation system, the method comprising: reducing water into hydrogen in an electrocoagulation reactor; and recovering the hydrogen at a hydrogen recovery apparatus.
58. The system or method of any of claims 48 to 57, wherein the electrocoagulation system is a modular electrocoagulation system according to any of claims 37 to 47.
59. A method of monitoring the condition of an electrode array in an electrocoagulation reactor, the method comprising: providing the electrode array with a current; measuring an electrical parameter associated with providing the current; comparing the measured electrical parameter with a predetermined value; and performing an electrode condition-dependent operation based on the comparison.
60. A method of monitoring the condition of an electrode array in an electrocoagulation reactor according to claim 59, wherein the electrical parameter is the total charge passed by the electrode array and the predetermined value is a predetermined charge value.
61. A method of monitoring the condition of an electrode array in an electrocoagulation 30 reactor according to claim 59 or 60, wherein the electrical parameter is a potential difference applied to the electrode array and the predetermined value is a predetermined potential difference value.
62. A method of monitoring the condition of an electrode array in an electrocoagulation 35 reactor according to any of claims 59 to 61, wherein the electrical parameter is the rate of change of a potential difference applied to the electrode array and the predetermined value is a predetermined rate of change value.
63. A method of monitoring the condition of an electrode array in an electrocoagulation reactor according to any of claims 59 to 62, wherein the predetermined value is a limit or threshold.
64. A method of monitoring the condition of an electrode array in an electrocoagulation reactor according to claim 63, wherein the electrode condition dependent operation is performed if the measured electrical parameter is below the predetermined limit or threshold.
65. A method of monitoring the condition of an electrode array in an electrocoagulation reactor according to any of claims 59 to 64, wherein the electrode condition dependent operation comprises: determining that the electrode array needs to be replaced; generating a warning message; triggering an alarm, initiating cleaning of the electrode array; or disabling the electrode array.
66. A method of monitoring the condition of an electrode array in an electrocoagulation reactor according to any of claims 59 to 65, wherein the electrode array is configured to operate in a unipolar configuration.
67. A method of monitoring the condition of an electrode array in an electrocoagulation 25 reactor according to any of claims 59 to 66, wherein the electrode array comprises sacrificial electrodes that are oxidised during operation, and optionally wherein the sacrificial electrodes comprise iron or aluminium.
68. A method of monitoring the condition of an electrode array in an electrocoagulation 30 reactor according to any of claims 59 to 67, wherein the current is a constant current.
69. An electrocoagulation system comprising: an electrocoagulation reactor comprising an electrode array; a current source connected to the electrode array; a measurement device configured to measure an electrical parameter associated with operating the current source; a processor; and a computer-readable medium comprising instructions which, when executed by the processor, causes the processor to perform a method according to any of claims 59 to 68.
70. An electrocoagulafion system according to claim 69, wherein the measurement device 5 comprises a voltmeter, ammeter, current integrator, current sensor and/or programmable logic controller.
71. An electrocoagulation system according to claim 69 or 70, wherein the current source is a constant current source.
72. A computer-readable medium comprising instructions which, when executed by a processor, causes the processor to perform a method according to any of claims 59 to 68.