System and method for electrochemical disinfection

Abstract

The invention relates to a method for electrochemical disinfection of an aqueous solution, the method comprising the steps of: providing one or more disinfection cells for storing an aqueous solution, each disinfection cell comprising one or more electrode pairs located therein; arranging the one or more disinfection cells along a flow path, the flow path comprising an inlet to the one or more disinfection cells, and an outlet from the one or more disinfection cells; determining a conductivity or specific conductance of the aqueous solution at the one or more disinfection cells; determining a voltage to apply across the one or more electrode pairs at a current sufficient to generate a disinfecting species therein as a function of the conductivity or specific conductance of the aqueous solution; and passing the current from the one or more electrode pairs to the aqueous solution to generate a modified aqueous solution.

Description

TECHNICAL FIELD

[0001] The present invention relates generally to disinfection of aqueous solutions, and more particularly, to electrochemical systems and methods for disinfection of aqueous solutions. BACKGROUND

[0002] Providing clean drinking water is vital to life. The quality of drinking water varies by location and often requires removal of microorganisms, such as bacteria (including Legionella) and other organisms, organic matter, pathogens, and combinations of these contaminants, before it can be safely consumed.

[0003] In areas where water is limited, wastewater can also be a valuable resource. However, contaminants must also be removed before it can be safely reused for irrigation, recreational use, or discharged to the environment.

[0004] Water disinfection methods have been proposed, such as heat disinfection, use of chlorine, chlorine dioxide, monochloramine, metal ions, ultraviolet light, and other such methods. However, conventional disinfection methods have difficulty in effectively eliminating Legionella and other harmful bacteria in water supply systems. Inadequate disinfection results in occasional outbreaks of Legionella-caused illness, and chlorine is identified as a source of potentially harmful disinfection byproducts, which leads to the need to develop alternative disinfection technologies, including electrochemical technologies.

[0005] In physical or electromechanical disinfection processes, microorganisms are removed or killed by irradiation with ultraviolet light or ionizing radiation, heating to high temperatures, ultrasound, or by separation through membrane filtration. The main disadvantage of physical disinfection methods is that these processes are only effective in the immediate surroundings of their operating devices.

[0006] It would be desirable to provide a method and system that improves or at least mitigates one or more of the above problems, or provides an alternative.

[0007] It would also be desirable to provide a method and system that improves or overcomes one or more of the disadvantages or inconveniences of known water disinfection methods and systems.

[0008] The citation of a patent, patent publication, or other publication herein is not intended to be an admission that any of the foregoing is prior art to the present invention, that the inventor or inventors were aware of any of the foregoing, or that any of the foregoing is numerically or logically antecedent to the present invention. SUMMARY

[0009] According to one aspect of the present application, there is provided a method for electrochemical disinfection of an aqueous solution, the method comprising the steps of: providing one or more disinfection tanks for storing an aqueous solution, each disinfection tank comprising one or more electrode pairs located therein; arranging the one or more disinfection tanks along a flow path, the flow path comprising an inlet to the one or more disinfection tanks, and an outlet from the one or more disinfection tanks; determining the electrical conductivity or specific conductance of the aqueous solution at the one or more disinfection tanks; determining a voltage to apply across the one or more electrode pairs at a current sufficient to generate a disinfection species therein, in dependence on the electrical conductivity or specific conductance of the aqueous solution; and passing a current from the one or more electrode pairs to the aqueous solution to generate a modified aqueous solution. The modified aqueous solution can have a higher concentration of disinfection species therein. The one or more disinfection tanks not only store the aqueous solution, but also facilitate the flow of the aqueous solution therethrough.

[0010] Advantageously, the method is suitable for electrochemically disinfecting a contaminated aqueous solution by passing a current from the one or more electrode pairs to the aqueous solution, thereby modifying contaminants therein by exposure to disinfection species (e.g. reactive oxygen species, hydrogen peroxide, ozone, oxygen, hydroxyl radicals, chlorine, and mixtures thereof). The species of disinfection species can depend on the aqueous solution. The voltage applied to the electrodes can be alternating current (AC) or direct current (DC). In either case, the power supply can be provided by a single-phase power supply or a three-phase power supply.

[0011] In one or more embodiments, the steps of determining the electrical conductivity or specific conductance of the aqueous solution and determining the voltage to apply across the one or more electrode pairs are performed continuously along the flow path.

[0012] In one or more embodiments, the method further comprises the step of determining an initial voltage to apply across the one or more electrode pairs in dependence on the electrical conductivity or specific conductance of the aqueous solution at the inlet. The inlet can be connected to the flow path in which the disinfection tanks are located.

[0013] In one or more embodiments, the initial voltage is determined such that the current induced by the aqueous solution when the voltage is applied across the one or more electrode pairs does not exceed the rated peak current of the power supply or the rated peak current of a power supply control device providing the voltage to the electrode pairs. The rated peak current can be the maximum current that the power supply can handle without tripping or being damaged or irreversibly damaged. Advantageously, this can also provide protection for the power supply and power supply control device providing the voltage to the electrode pairs.

[0014] In one or more embodiments, determining the electrical conductivity or specific conductance comprises detecting an increase or decrease in the current induced by the aqueous solution when the voltage is applied across the one or more electrode pairs. Advantageously, the electrical conductivity or specific conductance gradient is thereby regulated.

[0015] In one or more embodiments, the one or more pairs of electrodes are divided into two or more segments, each segment configured to individually apply a voltage to the aqueous solution. Individually applying a voltage across two or more segments increases or decreases the effective surface area of the one or more pairs of electrodes. Advantageously, the conductivity or specific conductance gradient is thereby modulated. By activating individual segments of a segmented electrode, very precise delivery of a desired current and voltage can be achieved through the segmented electrode. Individual segmented electrodes can be divided into segments of varying size to allow for selection of combinations of segments to provide increased precision of desired effective area selection. For example, when a segmented electrode is divided into three segments, the ratio of the relative effective areas of the segments is 1 :2:4, i.e., the segments preferably constitute four-sevenths, two-sevenths, and one-seventh of the total effective electrode area, respectively. In such an embodiment, appropriate activation of the three electrode segments allows for selection of any one of the seven available effective areas. Alternative segment area ratios and numbers of segments can be provided. For example, dividing one or more pairs of electrodes into n segments, the ratio of the effective surface areas of the individual segments is 1 :2:... :2 (n-1) .

[0016] In one or more embodiments, the two or more segments have uniform size.

[0017] In one or more embodiments, the two or more segments have different sizes.

[0018] In one or more embodiments, the one or more pairs of electrodes are substantially parallel and lie in a generally horizontal plane relative to the flow path.

[0019] In one or more embodiments, the one or more pairs of electrodes are substantially perpendicular and lie in a generally vertical plane relative to the flow path.

[0020] In one or more embodiments, wherein the one or more pairs of electrodes are at least partially coated with a material selected from the group consisting of boron-doped diamond (BDD), mixed metal oxide (MMO), antimony-doped tin oxide, and combinations thereof. Such materials can be used for anodic electrochemical reactions. The materials can include layered structures and include various binding materials.

[0021] In one or more embodiments, the one or more pairs of electrodes are at least partially formed of a material selected from the group consisting of a metal, a conductive polymer, carbon, a carbon-impregnated polymer.

[0022] In one or more embodiments, wherein the one or more pairs of electrodes are made of an electrically conductive inert material, such as graphite, carbon, and combinations thereof. Such materials can be used for anodic electrochemical reactions. The materials can include layered structures and include various binding materials.

[0023] In one or more embodiments, the method further comprises the step of measuring the flow rate of the aqueous solution flowing through the flow path. The method can further comprise the step of increasing or decreasing the flow rate of the aqueous solution flowing through the flow path to regulate the residence time of the aqueous solution in one or more of the disinfection cells. The residence time for a given volume of aqueous solution to receive electrical energy from the electrodes can be determined by measuring the flow rate of the aqueous solution through the channel. The flow rate can also be limited by one or more thresholds associated with the flow rate and / or pumping or regulation of the aqueous solution.

[0024] In one or more embodiments, the method further comprises the step of measuring the temperature of the aqueous solution flowing through the flow path. The temperature of the aqueous solution is also directly proportional to the current induced by the aqueous solution. The current can be effectively used to determine an increase or decrease in the temperature of the aqueous solution. Higher temperatures can assist in reducing the power of the disinfection cells while maintaining or increasing the rate of disinfection. Although higher temperatures can be achieved by pre-heating the incoming aqueous solution if necessary, heating the solution is not essential for the production of disinfection species.

[0025] In one or more embodiments, the method further comprises the steps of determining the temperature of the aqueous solution within the disinfection cells by measuring the current induced by the disinfection cells; and providing the temperature as feedback to a temperature controller configured to adjust the applied voltage to effectively heat or reduce heating of the aqueous solution.

[0026] In one or more embodiments, the method further comprises the steps of measuring the temperature of the aqueous solution at the outlet; and providing the temperature as feedback to a temperature controller configured to adjust the applied voltage to effectively heat or reduce heating of the aqueous solution.

[0027] In one or more embodiments, one or more of the disinfection cells are arranged in series along the flow path.

[0028] In one or more embodiments, the method can further comprise the step of not applying a voltage across one or more of the electrode pairs if the conductivity or specific conductance of the aqueous solution is outside a predetermined range. Advantageously, this can also provide protection for the power supply and power control device providing the voltage to the electrode pairs.

[0029] According to another aspect of the application, there is provided a system for electrochemical disinfection of an aqueous solution, the system comprising: one or more disinfection tanks for storing the aqueous solution, each disinfection tank comprising one or more pairs of electrodes located therein; the one or more disinfection tanks being arranged along a flow path, the flow path comprising an inlet to the one or more disinfection tanks, and an outlet from the one or more disinfection tanks; and a controller configured to: regulate flow of the aqueous solution from the inlet to the one or more disinfection tanks; determine electrical conductivity or specific conductance of the aqueous solution at the one or more disinfection tanks; determine a voltage to apply across the one or more pairs of electrodes at a current sufficient to generate a disinfecting species therein, in dependence on the electrical conductivity or specific conductance of the aqueous solution; and pass a current from the one or more pairs of electrodes to the aqueous solution to generate a modified aqueous solution.

[0030] In one or more embodiments, the controller is further configured to determine the electrical conductivity or specific conductance of the aqueous solution continuously, and to determine the voltage to apply across the one or more pairs of electrodes. The controller can determine the electrical conductivity or specific conductance via the sensor by a directly transmitted signal or via a digital universal interface or other bus.

[0031] In one or more embodiments, the controller is further configured to determine an initial voltage to apply across the one or more pairs of electrodes in dependence on the electrical conductivity or specific conductance of the aqueous solution at the inlet.

[0032] In one or more embodiments, the initial voltage is determined such that a current caused by the aqueous solution when the voltage is applied across the one or more pairs of electrodes does not exceed a rated peak current of a power supply.

[0033] In one or more embodiments, determining the electrical conductivity or specific conductance of the aqueous solution comprises detecting an increase or decrease in a current caused by the aqueous solution when the voltage is applied across the one or more pairs of electrodes.

[0034] In one or more embodiments, the one or more pairs of electrodes are divided into two or more segments, each segment being configured to be individually applied with a voltage by the controller. Advantageously, a conductivity or specific conductance gradient is thereby regulated.

[0035] In one or more embodiments, varying voltages are individually applied across the two or more segments to effectively increase or decrease an effective surface area of the one or more pairs of electrodes.

[0036] In one or more embodiments, the two or more segments have uniform dimensions.

[0037] In one or more embodiments, the two or more segments have different dimensions.

[0038] In one or more embodiments, the one or more pairs of electrodes are divided into n segments, the ratio of the effective surface area of each segment being 1 :2 :... :2 (n-1) .

[0039] In one or more embodiments, the one or more pairs of electrodes are substantially parallel and lie in a plane that is approximately horizontal with respect to the flow path.

[0040] In one or more embodiments, the one or more pairs of electrodes are substantially perpendicular and lie in a plane that is approximately vertical with respect to the flow path.

[0041] In one or more embodiments, the one or more pairs of electrodes are at least partially coated with a material selected from the group consisting of boron-doped diamond (BDD), mixed metal oxide (MMO), antimony-doped tin oxide, and combinations thereof.

[0042] In one or more embodiments, the one or more pairs of electrodes are at least partially formed of a material selected from the group consisting of a metal, a conductive polymer, carbon, and a carbon-impregnated polymer.

[0043] In one or more embodiments, the one or more pairs of electrodes are made of a conductive inert material, such as graphite, carbon, and combinations thereof.

[0044] In one or more embodiments, the controller is further configured to measure the flow rate of the aqueous solution flowing through the flow path.

[0045] In one or more embodiments, the controller is further configured to increase or decrease the flow rate of the aqueous solution flowing through the flow path to regulate the residence time of the aqueous solution in the one or more disinfection cells.

[0046] In one or more embodiments, the controller is further configured to measure the temperature of the aqueous solution flowing through the flow path.

[0047] In one or more embodiments, the controller is further configured to measure the temperature of the aqueous solution at the outlet; and provide the temperature as feedback to a temperature controller configured to heat or reduce the heating of the aqueous solution.

[0048] In one or more embodiments, the one or more disinfection cells are arranged in series along the flow path.

[0049] In one or more embodiments, the controller is further configured to not apply a voltage, or to vary the voltage, on the one or more pairs of electrodes if the conductivity or specific conductance of the aqueous solution is outside a predetermined range, thereby regulating the specific conductance gradient.

[0050] According to another aspect of the present application, there is provided a method for electrochemical disinfection of an aqueous solution, the method comprising the steps of: passing the aqueous solution from an inlet along a flow path to an outlet, the flow path comprising at least a first disinfection cell and a second disinfection cell arranged along the flow path such that aqueous solution passing through the first disinfection cell subsequently passes through the second disinfection cell, each disinfection cell comprising at least one electrode pair between which an electric current is passed through the aqueous solution to generate a disinfecting species therein during its passage along the flow path, and at least one of the disinfection cells comprising at least one segmented electrode comprising a plurality of electrically separable segments such that the effective surface area of the segmented electrode is controlled by selectively activating the segments such that when a voltage is applied to an activated electrode segment, the resulting electric current will depend in part on the effective surface area; determining and simultaneously regulating the electrical conductivity or conductivity gradient of the aqueous solution at the inlet and subsequent disinfection cells; determining the voltage and current required to be delivered by the first disinfection cell to the aqueous solution to increase the concentration of disinfecting species therein by a first amount in dependence on the measured electrical conductivity or specific conductivity of the aqueous solution; determining the electrical conductivity or specific conductivity of the modified aqueous solution resulting from operation of the first disinfection cell; determining the voltage and current required to be delivered by the second disinfection cell to the aqueous solution to increase the concentration of disinfecting species therein by a second amount in dependence on the electrical conductivity or specific conductivity of the modified aqueous solution; and activating segments of the segmented electrode in a manner to deliver the desired current and voltage through the segmented electrode.

[0051] Advantageously, the method is suitable for electrochemically disinfecting a contaminated aqueous solution by modifying contaminants therein by exposure to disinfecting species (e.g. reactive oxygen species, hydrogen peroxide, ozone, oxygen, hydroxyl radicals, chlorine and mixtures thereof) by gradually passing an electric current from the one or more electrode pairs to the aqueous solution. The voltage applied to the electrodes can be alternating current (AC) or direct current (DC). BRIEF DESCRIPTION OF DRAWINGS

[0052] The present application will now be described in further detail with reference to the drawings. It is to be understood that the specific details illustrated in the accompanying drawings are not to be regarded as limiting the general nature of the preceding description of the present application.

[0053] Figure 1 A simplified block diagram of an aqueous solution flow path through n disinfection cells according to an embodiment of the present application is shown;

[0054] Figure 2 A flow diagram of a method of electrochemical disinfection of an aqueous solution through n disinfection cells according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0055] The present invention is applicable to the disinfection of aqueous solutions by employing an advanced oxidation process via electrochemical disinfection that generates disinfecting species such as hydroxyl radicals (OH).

[0056] In one embodiment, the aqueous solution is water, which will be used to facilitate the description of the present invention in connection with this exemplary, but non-limiting, application. The present invention is also suitable for incorporation with water heating systems, where higher temperatures can help reduce the power of the disinfection tank while maintaining or increasing the disinfection rate. Higher temperatures can be achieved, if necessary, by pre-heating the input aqueous solution, but heating the solution is not necessary for the generation of disinfecting species.

[0057] The term electrochemical disinfection generally relates to the modification of contaminants, including microorganisms, by passing an electric current through the aqueous component of an aqueous solution with the aid of a coated electrode.

[0058] The term "coated" as used herein in connection with "coated electrode" can refer to the attachment of a material to the outer surface of another material. The attachment can be partial or complete covering of the surface of another material, and can be any mechanical, chemical or other force or combination.

[0059] The term "manufacture" can refer to the production of one or more electrode pairs, which can be made of electrically conductive inert materials, such as graphite, carbon and combinations thereof.

[0060] Figure 1 A simplified block diagram of a system 100 for electrochemical disinfection of aqueous solutions in accordance with an embodiment of the present invention is shown. An aqueous solution is caused to flow through three disinfection tanks 102, 104 and 106 arranged along a flow path 108. The flow path 108 includes an inlet 110 leading to the disinfection tanks 102, 104 and 106, and an outlet 112 exiting from the disinfection tanks 102, 104 and 106. The disinfection tanks 102, 104 and 106 store the aqueous solution as it flows through the flow path, and those skilled in the art will recognize suitable designs for providing this functionality, such as tubes or pipes.

[0061] In one or more embodiments, the disinfection tanks 102, 104 and 106 are housed within, or integrated with, a body 114. The body 114 is preferably made of a non-conductive material, such as a synthetic plastic material. However, the body 114 can be connected to a conductive metal water pipe, such as a copper pipe. Accordingly, the body 114 includes Figure 1A ground 116 is shown to electrically ground any metal piping connected to the system 100. Ideally, the ground 116 is connected to the power supply ground of the electrical installation in which the disinfection system of the present embodiment is installed. Since the ground 116 can cause a current to flow through the water passing through the system 100 by way of the electrode voltage, activation of the ground fault protection connected to the power supply of the system can be achieved in the form of a circuit breaker or residual current device (RCD). In a preferred form of the embodiment, the system 100 includes a ground fault circuit protection device.

[0062] When the outlet tap or cock (not shown) is opened, the aqueous solution flows through the body 114 as shown by the flow path arrow 108.

[0063] In the illustrated embodiment, the flow path 108 is provided with three disinfection cells 102, 104 and 106 which include respective pairs of electrodes 102a, 104a and 106a. However, it will also be appreciated that additional or fewer disinfection cells can be used. The electrodes can be a metal or non-metal conductive material coated with boron-doped diamond (BDD), mixed metal oxide (MMO) or antimony-doped tin oxide or a combination of BDD, MMO or antimony-doped tin oxide, such as a conductive plastic material, carbon or carbon impregnated material or the like.

[0064] It is important that the electrode substrate and coating are selected from a group of conductive materials (or combinations of materials) to minimise chemical reactions and / or electrolysis while promoting the production of disinfecting species.

[0065] The pairs of electrodes can also be made from conductive inert materials such as graphite, carbon and combinations thereof.

[0066] In one or more embodiments, one electrode of each pair of electrodes 102a, 104a and 106a is divided into two or more segments, each segment configured to apply a separate voltage. The segmented electrodes 102a, 104a and 106a of each pair of electrodes are connected to a common switched power path 118 by separate voltage power supply control devices Q1, Q2,..., Qn, while the other electrode 102b, 104b and 106b of each pair of electrodes is connected to an input single phase neutral or three phase voltage source 120 respectively. The independent voltage power supply control devices Q1, Q2,..., Qn switch the common power supply in accordance with power supply management controls provided by a controller 122. The controller 122 can include a microprocessor which interacts with other components of the system 100 to regulate or measure the flow rate of the aqueous solution, detect ground faults, measure the temperature at the inlet 110 and / or outlet 112 (or at other locations along the flow path 108), and / or measure the current 124 induced by the aqueous solution at the disinfection cells 102, 104 and 106 (or at other locations along the flow path 108).

[0067] The current supplied to the sanitizing cell 102 (and possibly to the sanitizing cells 104 and 106) is measured by a current measuring device 124. Only one current measuring device 124 is shown. However, it should be understood that the current at each of the sanitizing cells 102, 104, 106 can be measured by a separate current measuring device 124. For example, the current measurement by a Hall current sensor electrically connected to the output of the power supply control device Ql, Q2,..., Qn is transmitted to the power supply management controller 122.

[0068] In one or more embodiments, the current measuring device 124 is connected to the power supply control device Ql, Q2,..., Qn so as to be operable to determine the current from the single or three phase power supply 120 caused by the aqueous solution. A current amplifier can be used to amplify the output signal of the current measuring device 124. The controller 122 then receives the amplified signal and compares it to a threshold level. The calculated current threshold level is typically set in the ampere range so that the current caused by the aqueous solution remains at or near the threshold level only when the aqueous solution is flowing through the flow path 108. When the system 100 is in use, the controller 122 continues to compare the output of the current measuring device 124 to the threshold level, makes appropriate adjustments to the selection of the electrode pair combination, and makes appropriate adjustments to the voltage supplied to the electrode pairs 102a, 104a and 106a so as to maintain a substantially constant current to facilitate the generation of the sanitizing species in the aqueous solution while always ensuring that the current handling capacity of the power supply is not exceeded. However, when the system 100 enters a non-use state, such as a standby mode, the controller 122 will correspondingly remove the voltage applied to the sanitizing cells 102, 104 and 106.

[0069] As a non-limiting example, the current measuring device 124 can be capable of sensing a small increase in the detected current through the aqueous solution to determine the ideal voltage to apply to the electrode pairs 102a, 104a and 106a for the generation of sanitizing species therein. That is, the current measurement is provided as an input signal to the controller 122 as the power supply controller through the input interface 124.

[0070] In one or more embodiments, the controller 122 can also receive a signal through the input interface 124 from a flow rate measuring device or a flow rate switch 126 including a flow rate limit located proximate the inlet 110 of the body 114. The volume of the aqueous solution passing between any of the electrode pairs 102a, 104a and 106a can be precisely determined by measuring the flow rate. Similarly, the residence time of a given volume of the aqueous solution to receive electrical energy from the electrodes can be determined by measuring the flow rate of the aqueous solution through the channel. It should be understood that the flow rate can be limited by one or more threshold values related to the flow rate and / or the pumping or regulation of the aqueous solution.

[0071] Disinfection of the aqueous solution is performed by exposing the charged solution to the coated electrodes in the disinfection cell (as described above). The advanced oxidation process is facilitated by providing the current required by the aqueous solution being disinfected.

[0072] Thus, the current flowing through the aqueous solution can be used as a measure of the aqueous solution conductivity or specific conductance, and thus the required variation of the selected applied voltage and electrode combination to cause a current sufficient to generate disinfecting species can be determined.

[0073] The conductivity or specific conductance, and thus the specific conductance of the aqueous solution, varies with temperature, thereby causing a specific conductance gradient along the aqueous solution flow path 108. In one or more embodiments, the controller 122 also receives a signal from an input temperature measuring device 128 through the signal input interface 124 to measure the aqueous solution temperature at the inlet 110. An output temperature measuring device 130 can also be provided to measure the aqueous solution temperature at the outlet 112. The signal from the output temperature measuring device 130 can be provided as feedback to the controller 122, thereby allowing continuous monitoring of the aqueous solution temperature.

[0074] The system 100 of the present embodiments is also capable of accommodating variations in the aqueous solution conductivity or specific conductance, whether arising from the particular location in which the system is installed or arising from time to time at a single location, or due to variations in the aqueous solution temperature. In this regard, the aqueous solution conductivity or specific conductance is determined to be directly proportional to the current induced in the aqueous solution flowing through the disinfection cells 102, 104 and 106.

[0075] For a given applied voltage, variations in the aqueous solution conductivity or specific conductance will cause variations in the amount of current induced by each electrode. The present embodiments monitor the variations and ensure that the system 100 induces the desired current level by using the determined conductivity or specific conductance value, thereby initially selecting a commensurate electrode segment combination before operating the system. The electrodes shown by 102a, 104a, 106a are divided into a plurality of electrode segments 102ai and 102aii, 104ai, 104aii, 106ai and 106aii.

[0076] For each respective electrode, the ai segment is made to typically form about one third or two thirds of the active area of the electrode, the aii segment is made to typically form about two thirds or one third of the active area of the electrode, and so on. The appropriate segment or appropriate combination of segments is selected so that the effective area of the electrode is any one of three available values of electrode area. Thus, for a highly conductive aqueous solution, a smaller electrode area can be selected so that for a given voltage, the current induced by the electrode is prevented from rising above a desired level or a safety level, while still maintaining the current induced to promote electrochemical disinfection. Conversely, for a poorly conductive aqueous solution, a larger electrode area can be selected so that the current induced is required to achieve the desired disinfection. Selection of segments can be simply achieved by appropriate activation or deactivation of the power switching devices Q1,..., Qn.

[0077] In particular, the combined surface area of the selected electrode segments is specifically calculated to ensure that the rated maximum current value of the power supply system is not exceeded.

[0078] In one or more embodiments, the controller 122 receives various monitored input signals and makes the necessary calculations for electrode active area selection, desired voltage and current for the electrode pair to promote electrochemical disinfection of the aqueous solution flowing through the flow path 108. The controller 122 controls the voltage supply individually according to each of the single phase power supply 120 or three separate phases of the three phase power supply 120 connected to each of the electrode segments 102, 104 and 106.

[0079] The voltage supply is controlled individually by independent control signals from the controller 122 to the power switching devices Q1,..., Qn. Thus, it will be appreciated that based on the various parameters for which the controller 122 receives typical input signals, the computing device under the control of the software program or firmware within the controller 122 calculates the control pulses required by the power switching devices to supply the required voltage to achieve the desired disinfection of the aqueous solution flowing through the flow path 108, which will be discussed in Figure 2 .

[0080] In some embodiments, the controller 122 also converts the readings from the current measuring device 124, temperature sensors 128 and 130, flow rate measuring device or flow rate switch 126 including flow rate restriction, power switching devices Q1,..., Qn, and so on, to digital values and communicates the information to the digital communication device 132 based on these digital values. It will be appreciated that filtering methods can also be used, such as but not limited to, those that can be particularly suitable for implementation in firmware including moving average filters, uniform weighting filters, and so on, or combinations of these filters. This information can then be communicated through a wired digital communication service such as but not limited to Ethernet, RS485, and so on, or a wireless connection such as an 802.11 Wi-Fi network or Bluetooth TM) to other devices (such as a computer, smartphone, tablet, laptop, desktop, server computer, and other forms of computer systems) for processing by the application 134 or a cloud computing platform. Advantageously, this can provide remote monitoring and / or configuration of the system 100 to facilitate an operator to modify parameters such as flow rate or electrical power based on the properties of the water solution being disinfected. For example, for purifying drinking water, the flow rate can be decreased and / or the temperature increased when the solution conductivity is low. Furthermore, system maintenance and management can also be facilitated by the digital communication method employed.

[0081] It will be appreciated that there can be various control implementation means. For example, in various embodiments, the system 100 can include an artificial intelligence based control mechanism, which can partly use a cloud based service. As mentioned above, a decision can be made whether to increase or decrease the flow rate (i.e. increase or decrease the residence time of the water solution in the disinfection tank) or the voltage (and subsequently the current) based on the multi-sensor inputs provided to the controller 122 (or to other platforms through the wireless transceiver 132) through the interface 124. This cooperation between the communication and computation can happen automatically in the controller 122, the application 134 or a cloud hosted application. Furthermore, the controller 122 can perform machine learning based on the input data. Based on this information, the system 100 can preemptively make changes to the flow rate, voltage, temperature, etc.

[0082] It will be appreciated that any suitable digital communication protocol can be used for the communication, including but not limited to Wi-Fi 802.11, 6LowPan / ZIGBEE TM 802.15, Ethernet 802.3, 802.11 and 802.15.4 and RS485.

[0083] The wireless transceiver 132 can also be adapted to facilitate a remote firmware update mechanism and communication with the controller 122. As will be appreciated by the skilled person, the remote firmware update mechanism can be adapted, together with the controller 122, to periodically check a remote repository for updates, download firmware updates, and compare the downloaded firmware with the existing firmware to determine the necessity of installing the downloaded firmware, etc.

[0084] Figure 2 A flowchart of a method for electrochemical disinfection of a water solution according to one embodiment of the present application is shown, including reference Figure 1 to the embodiments discussed.

[0085] The method 200 starts at start block 202, and at step 204, the conductivity or specific conductance of the water solution is determined at the inlet of a first disinfection tank comprising a first electrode pair. In one or more embodiments, the voltage supplied from the voltage supply control device (i.e. reference Figure 1Q1) The conductivity or specific conductance is determined by measuring the current induced through the aqueous solution when an initial voltage is applied across the first electrode pair.

[0086] At step 206, the voltage to be applied across the first electrode pair at a current sufficient to generate disinfecting species in the aqueous solution is determined based on the conductivity or specific conductance of the aqueous solution. At step 208, the electrode segment combination is determined. For example, when a segmented electrode is divided into three segments, the ratio of the relative effective areas of the segments can be 1 :2:4, i.e., the segments preferably make up four-sevenths, two-sevenths, and one-seventh, respectively, of the total effective electrode area. In one or more embodiments, all segments can be activated for aqueous solutions having a relatively low conductivity or specific conductance, and one or more of the segments can be activated for aqueous solutions having a relatively high conductivity or specific conductance.

[0087] After the applied voltage and electrode segment combination are determined, the current induced by the aqueous solution is then measured at step 210.

[0088] At step 212, it is determined whether the system current limit has been exceeded. If the system current limit has been exceeded, the method ends at step 218. If the system current limit has not been exceeded, it is determined at step 214 whether there is sufficient current to generate the disinfecting species required for disinfection.

[0089] In one or more embodiments, the method returns to step 216 such that the conductivity or specific conductance is continuously determined and the voltage supplied and electrode combination in all of the disinfection tanks 102, 104, and 106 are appropriately changed to maintain a substantially constant current to facilitate the efficient generation of disinfecting species in the aqueous solution. Advantageously, by returning to step 216, the method is able to accommodate changes in the conductivity or specific conductance of the aqueous solution, whether it is caused by the particular location in which the system is installed or is a temporary increase or decrease in mineral content or temperature that occurs from time to time at a single location.

[0090] In one or more embodiments, steps 210-216 can be repeated for n disinfection tanks until the method ends at step 218.

[0091] It should be appreciated that one or more general purpose or special purpose controller or processor (or "processing device") such as a microcontroller, a microprocessor, a digital signal processor, a custom processor and a field programmable gate array (FPGA), and singly or in combination with stored program instructions (including software and firmware) that control one or more processors to implement some, most or all of the functions in the methods and / or apparatus described herein, can be included in some embodiments. Additionally, some or all of the functions can be implemented in hardware, for example, a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), where various functionality or some combination of functions are implemented in custom logic. Of course, combinations of the two approaches should also be understood to be within the scope of the present disclosure.

[0092] The use of the term "include", as used in this specification (including the claims) should be interpreted as explicitly reciting the presence of the stated features, integers, steps or components but not the exclusion of one or more other features, integers, steps or components or groups thereof.

[0093] While the application has been described in connection with limited number of embodiments, it will be understood that numerous alternatives, modifications and variations of the present application are as possible in light of the foregoing description. Accordingly, the present application is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the disclosed application.

Claims

1. A method for electrochemical disinfection of aqueous solutions, the method comprising the following steps: One or more disinfection tanks are provided for storing aqueous solutions, each disinfection tank including one or more electrode pairs located therein; The one or more disinfection pools are arranged along a flow path, the flow path including an inlet leading to the one or more disinfection pools and an outlet leaving the one or more disinfection pools; The conductivity or specific conductivity of the aqueous solution is measured in one or more disinfection tanks; The current in each disinfection tank is determined, thereby determining whether the temperature in the disinfection tank increases or decreases. The change in conductivity caused by the change in current detected by the temperature change of the aqueous solution in the disinfection tank is determined, thereby determining the voltage applied to the one or more electrode pairs at a current sufficient to generate disinfectant therein. and The current is passed from the one or more electrode pairs to the aqueous solution to produce a modified aqueous solution.

2. The method as described in claim 1, wherein, The steps of measuring the conductivity or specific conductivity of the aqueous solution and determining the voltage applied to the one or more electrode pairs are performed continuously along the flow path.

3. The method of claim 2, further comprising the step of determining an initial voltage applied to the one or more electrode pairs based on the conductivity or specific conductivity of the aqueous solution at the inlet.

4. The method of claim 3, wherein, The initial voltage is determined such that the current induced by the aqueous solution when a voltage is applied to the one or more electrode pairs does not exceed the rated peak current of the power source supplying the voltage to the one or more electrode pairs.

5. The method according to any one of claims 1 to 4, wherein, Determining the conductivity or specific conductivity of the aqueous solution includes detecting the increase or decrease in current caused by the aqueous solution due to temperature changes when a voltage is applied to one or more electrode pairs.

6. The method according to any one of claims 1 to 4, wherein, The one or more electrode pairs are divided into two or more segments, each segment being configured to apply a voltage to the aqueous solution individually.

7. The method of claim 6, wherein, Applying voltage individually to the two or more segments increases or decreases the effective surface area of ​​the one or more electrode pairs.

8. The method of claim 6, wherein, The two or more segments have uniform dimensions.

9. The method of claim 6, wherein, The two or more segments have different dimensions.

10. The method of claim 9, wherein, The one or more electrode pairs are divided into n segments, and the ratio of the effective surface area of ​​each segment is 1:2:……:2 (n-1) .

11. The method according to any one of claims 1 to 4, wherein, The one or more electrode pairs are substantially parallel and located in a plane that is generally horizontal relative to the flow path.

12. The method according to any one of claims 1 to 4, wherein, The one or more electrode pairs are substantially perpendicular and located in a plane that is generally perpendicular to the flow path.

13. The method according to any one of claims 1 to 4, wherein, The one or more electrode pairs are at least partially coated with a material selected from the group consisting of boron-doped diamond (BDD), mixed metal oxide (MMO), antimony-doped tin oxide, and combinations thereof.

14. The method according to any one of claims 1 to 4, wherein, The one or more electrode pairs are formed at least in part from a material selected from the group consisting of metals, conductive polymers, carbon, and carbon-impregnated polymers.

15. The method according to any one of claims 1 to 4, wherein, The one or more electrode pairs are formed of a conductive inert material, including graphite, carbon, and combinations thereof.

16. The method of any one of claims 1 to 4, further comprising the step of measuring the flow rate of the aqueous solution flowing through the flow path to calculate the voltage required to generate an electric current sufficient to produce a disinfectant therein.

17. The method of claim 16, further comprising the step of increasing or decreasing the flow rate of the aqueous solution flowing through the flow path to regulate the residence time of the aqueous solution in the one or more disinfection tanks, the residence time being such that a voltage is applied to induce a current in the aqueous solution sufficient to generate a disinfectant substance therein.

18. The method of any one of claims 1 to 4, further comprising the step of measuring the temperature of the aqueous solution flowing through the flow path at the outlet of the disinfection system to calculate the change in conductivity.

19. The method of claim 18, further comprising the steps of: measuring the temperature of the aqueous solution at the outlet; and The temperature is provided as feedback to a temperature controller, which is configured to increase or decrease the heating of the aqueous solution.

20. The method according to any one of claims 1 to 4, wherein, The one or more disinfection pools are arranged in series along the flow path.

21. The method of any one of claims 1 to 4, further comprising the step of: if the conductivity or specific conductivity of the aqueous solution exceeds a predetermined range, then not applying a voltage to the one or more electrodes, or changing the voltage.

22. A system for electrochemical disinfection of aqueous solutions, the system comprising: One or more disinfection tanks for storing aqueous solutions, each disinfection tank including one or more electrode pairs located therein; The one or more disinfection pools are arranged along a flow path, the flow path including an inlet leading to the one or more disinfection pools and an outlet exiting from the one or more disinfection pools; and The controller is configured as follows: Regulate the flow of the aqueous solution from the inlet to the one or more disinfection tanks; The conductivity or specific conductivity of the aqueous solution is measured in one or more disinfection tanks; The current in each disinfection tank is determined, thereby determining whether the temperature in the disinfection tank increases or decreases. The change in conductivity caused by the change in current detected by the temperature change of the aqueous solution in the disinfection tank is determined, thereby determining the voltage applied to the one or more electrode pairs at a current sufficient to generate disinfectant therein. and An electric current is passed from the one or more electrode pairs to the aqueous solution to produce a modified aqueous solution.

23. The system of claim 22, wherein, The controller is further configured to continuously measure the conductivity gradient of the aqueous solution and thereby calculate the voltage applied to the one or more electrode pairs.

24. The system of claim 22, wherein, The controller is further configured to determine the initial voltage applied to the one or more electrode pairs based on the conductivity or specific conductivity of the aqueous solution at the inlet.

25. The system of claim 24, wherein, The initial voltage is determined such that the current induced by the aqueous solution when a voltage is applied to the one or more electrode pairs does not exceed the rated peak current of the power source supplying the voltage to the one or more electrode pairs.

26. The system as claimed in any one of claims 22 to 25, wherein, Determining the conductivity or specific conductivity of the aqueous solution includes detecting the increase or decrease in current caused by the aqueous solution when a voltage is applied to one or more electrode pairs.

27. The system as claimed in any one of claims 22 to 25, wherein, The one or more electrode pairs are divided into two or more segments, each segment being configured to apply voltage individually via the controller to achieve effective management of varying aqueous conductivity gradients.

28. The system of claim 27, wherein, Applying voltage individually to the two or more segments increases or decreases the effective current induced by the aqueous solution through the increase or decrease of the electrode surface area.

29. The system of claim 27, wherein, The two or more segments have uniform dimensions.

30. The system of claim 27, wherein, The two or more segments have different dimensions.

31. The system of claim 30, wherein, The one or more electrode pairs are divided into n segments, and the ratio of the effective surface area of ​​each segment is 1:2:……:2 (n-1) .

32. The system as claimed in any one of claims 22 to 25, wherein, The one or more electrode pairs are substantially parallel and located in a plane that is generally horizontal relative to the flow path.

33. The system as claimed in any one of claims 22 to 25, wherein, The one or more electrode pairs are substantially perpendicular and located in a plane that is generally perpendicular to the flow path.

34. The system as claimed in any one of claims 22 to 25, wherein, The one or more electrode pairs are at least partially coated with a material selected from the group consisting of boron-doped diamond (BDD), mixed metal oxide (MMO), antimony-doped tin oxide, and combinations thereof.

35. The system as claimed in any one of claims 22 to 25, wherein, The one or more electrode pairs are formed at least in part from a material selected from the group consisting of metals, conductive polymers, carbon, and carbon-impregnated polymers.

36. The system as claimed in any one of claims 22 to 25, wherein, The one or more electrode pairs are made of a conductive inert material, including graphite, carbon, and combinations thereof.

37. The system as claimed in any one of claims 22 to 25, wherein, The controller is further configured to measure the flow rate of the aqueous solution flowing through the flow path.

38. The system of claim 37, wherein, The controller is further configured to increase or decrease the flow rate of the aqueous solution flowing through the flow path to regulate the residence time of the aqueous solution in the one or more disinfection tanks.

39. The system as claimed in any one of claims 22 to 25, wherein, The controller is further configured to measure the temperature of the aqueous solution flowing through the flow path to calculate the change in the conductivity of the aqueous solution.

40. The system of claim 39, wherein, The controller is further configured to measure the temperature of the aqueous solution at the outlet; and The temperature is provided as feedback to a temperature controller configured to increase or decrease the heating of the aqueous solution and to enable the system to calculate the change in the conductivity of the aqueous solution.

41. The system as claimed in any one of claims 22 to 25, wherein, The one or more disinfection pools are arranged in series along the flow path.

42. The system as claimed in any one of claims 22 to 25, wherein, The controller is further configured to not apply voltage to the one or more electrode pairs if the conductivity or specific conductivity of the aqueous solution exceeds a predetermined range.

43. A method for electrochemical disinfection of aqueous solutions, the method comprising the following steps: The aqueous solution is directed from an inlet to an outlet along a flow path, the flow path including at least a first disinfection tank and a second disinfection tank arranged along the flow path, such that the aqueous solution passing through the first disinfection tank subsequently passes through the second disinfection tank, each disinfection tank including at least one electrode pair, between which current flows through the aqueous solution to generate disinfectant therein during its passage along the flow path, and at least one of the disinfection tanks including at least one segmented electrode, the segmented electrode including a plurality of electrically separated segments, such that the effective surface area of ​​the segmented electrode is controlled by selectively activating the segments, such that when a voltage is applied to the activated electrode segment, the resulting current will depend in part on the effective surface area; The conductivity or specific conductivity of the aqueous solution at the inlet is measured; The voltage and current required to increase the concentration of the disinfectant in the aqueous solution by a first amount are determined based on the measured conductivity or specific conductivity of the aqueous solution. The conductivity or specific conductivity of the modified aqueous solution generated by the operation of the first disinfection tank was measured. The voltage and current required to increase the concentration of the disinfectant in the aqueous solution by a second amount are determined based on the conductivity or specific conductivity of the modified aqueous solution. and The segments of the segmented electrode are activated in a manner that effectively delivers the desired current and voltage through the segmented electrode.

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