System and method for electrochemical disinfection

1 . A method for electrochemical disinfection of an aqueous solution, the method comprising the steps of:

providing one or more disinfecting cells for retaining an aqueous solution, each disinfecting cell including one or more electrode pairs positioned therein;

arranging the one or more disinfecting cells along a flow path, the flow path including an inlet to and an outlet from the one or more disinfecting cells;

determining at the one or more disinfecting cells an electrical conductivity, or specific conductance of the aqueous solution;

determining, in each of the one or more disinfecting cells, a temperature of the aqueous solution within the disinfecting cell by the measurement of an electric current drawn by the aqueous solution, wherein the temperature of the aqueous solution is directly proportional to the electric current being drawn by the aqueous solution;

determining the electrical conductivity by detecting an increase or decrease in the electric current drawn by the aqueous solution and determining, from the electrical conductivity, a voltage to apply across the one or more electrode pairs at a current sufficient to produce disinfection species therein; and

passing the current from the one or more electrode pairs to the aqueous solution to produce a modified aqueous solution.

2 . The method of claim 1 , wherein 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.

3 . The method of claim 2 , further comprising the step of determining from the electrical conductivity, or specific conductance of the aqueous solution at the inlet, an initial voltage to apply across the one or more electrode pairs.

4 . The method of claim 3 , wherein the initial voltage is determined such that the current drawn by the aqueous solution upon application of the voltage across the one or more electrode pairs does not exceed a peak current rating of an electrical supply supplying voltage to one or more electrode pairs.

5 . The method of claim 1 , wherein determining the electrical conductivity, or specific conductance of the aqueous solution includes detecting an increase or decrease in the current drawn by the aqueous solution due to a change in aqueous solution temperature upon application of the voltage across the one or more electrode pairs.

6 . The method of claim 1 , wherein the one or more electrode pairs are segmented into two or more segments, each segment being configured to individually apply voltage to the aqueous solution.

7 . The method of claim 6 , wherein individually applying the voltages across the two or more segments increases or decreases an effective surface area of the one or more electrode pairs.

8 . The method of claim 1 , wherein the one or more electrode pairs are at least in part 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.

9 . The method of claim 1 , wherein the one or more electrode pairs are formed at least in part from a material selected from the group consisting of metal, conductive polymer, carbon, carbon impregnated polymer.

10 . The method of claim 1 , further comprising the step of measuring a flow rate of the aqueous solution flowing through the flow path to calculate the voltage to be applied in order to draw the current sufficient to produce the disinfection species therein, and increasing or decreasing the flow rate of the aqueous solution flowing through the flow path to regulate a residency time of the aqueous solution in the one or more disinfecting cells in order for the voltage applied to allow the aqueous solution to draw the current sufficient to produce the disinfection species therein.

11 . A system for electrochemical disinfection of an aqueous solution, the system comprising:

one or more disinfecting cells for retaining an aqueous solution, each disinfecting cell including one or more electrode pairs positioned therein;

the one or more disinfecting cells arranged along a flow path, the flow path including an inlet to and an outlet from the one or more disinfecting cells; and

a controller configured to:

regulate a flow of an aqueous solution from the inlet to the one or more disinfecting cells;

determine at the one or more disinfecting cells an electrical conductivity, or specific conductance of the aqueous solution;

determine, in each of the one or more disinfecting cells, a temperature of the aqueous solution within the disinfecting cell by the measurement of an electric current drawn by the aqueous solution, wherein the temperature of the aqueous solution is directly proportional to the electric current being drawn by the aqueous solution;

determine the electrical conductivity by detecting an increase or decrease in the electric current drawn by the aqueous solution and determine, from the electrical conductivity, a voltage to apply across the one or more electrode pairs at a current sufficient to produce disinfection species therein; and

pass the current from the one or more electrode pairs to the aqueous solution to produce a modified aqueous solution.

12 . The system of claim 11 , wherein the controller is further configured to determine an electrical conductivity gradient of the aqueous solution and thereby calculate the voltage to apply across the one or more electrode pairs continuously.

13 . The system of claim 11 , wherein the controller is further configured to determine from the electrical conductivity, or specific conductance of the aqueous solution at the inlet an initial voltage to apply across the one or more electrode pairs.

14 . The system of claim 13 , wherein the initial voltage is determined such that the current drawn by the aqueous solution upon application of the voltage across the one or more electrode pairs does not exceed a peak current rating of an electrical supply supplying voltage to one or more electrode pairs.

15 . The system of claim 11 , wherein determining the electrical conductivity, or specific conductance of the aqueous solution includes detecting an increase or decrease in the current drawn by the aqueous solution upon application of the voltage across the one or more electrode pairs.

16 . The system of claim 11 , wherein the one or more electrode pairs are segmented into two or more segments, each segment being configured to individually apply voltage by the controller to allow effective management of changes in an aqueous solution conductivity gradient.

17 . The system of claim 16 , wherein individually applying the voltage across the two or more segments increases or decreases the effective electric current drawn by the aqueous solution by virtue of electrode surface area.

18 . The system of claim 11 , wherein the one or more electrode pairs are at least in part 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.

19 . The system of claim 11 , wherein the one or more electrode pairs are formed at least in part from a material selected from the group consisting of metal, conductive polymer, carbon and carbon impregnated polymer.

20 . The system of claim 11 , wherein the controller is further configured to measure a flow rate of the aqueous solution flowing through the flow path and to increase or decrease the flow rate of the aqueous solution flowing through flow path to regulate a residency time of the aqueous solution in the one or more disinfecting cells.

21 . A method for electrochemical disinfection of an aqueous solution, the method comprising the steps of:

passing the aqueous solution along a flow path from an inlet to an outlet, the flow path including at least first and second disinfecting cells positioned along the flow path such that the aqueous solution passing the first disinfecting cell subsequently passes the second disinfecting cell, each disinfecting cell including at least one electrode pair between which an electric current is passed through the aqueous solution to produce disinfection species therein during its passage along the flow path, and wherein at least one of the disinfecting cells includes at least one segmented electrode, the segmented electrode comprising a plurality of electrically separable segments allowing an effective surface area of the segmented electrode to be controlled by selectively activating the segments such that upon application of a voltage to the activated electrode segment(s), current drawn will depend in part upon the effective surface area;

determining the aqueous solution conductivity, or specific conductance at the inlet;

determining from measured aqueous solution conductivity, or specific conductance a required voltage and current to be delivered to the aqueous solution by the first disinfecting cell to raise the concentration of disinfection species therein by a first amount;

determining a modified aqueous solution conductivity, or specific conductance resulting from operation of the first disinfecting cell;

determining from the modified aqueous solution conductivity, or specific conductance a required voltage and current to be delivered to the aqueous solution by the second disinfecting cell to raise the concentration of disinfection species therein by a second amount; and

activating segments of the segmented electrode in a manner to effect delivery of desired current and voltage by the segmented electrode.