Field

This invention relates to adjusting parameters of a fluid, such as adjusting pH and electrode potential (or reduction/oxidation (REDOX) potential), without using additional chemicals or agents. The invention also relates to adding energy to a fluid to effect the disruption of chemical bonds. Embodiments may be used to promote and control a wide range of chemical reactions, including reactions for the destruction of toxic compounds and drugs, to promote sedimentation of particulate matter, to precipitate heavy metals or selected compounds, to kill microorganisms, and to destroy biological compounds.

Background

Particles, such as particulate matter, droplets, and microorganisms may acquire or release electrons ffom/to a surrounding fluid medium due to a difference in surface energy. As a result, they tend to become negatively or positively charged. A second layer of counter ions may then bond to the particle surface forming what is referred to as an electrical double layer. Since like charges repel, as charge increases, it becomes more difficult for particles to agglomerate or flocculate or to take part in chemical reactions. The electrical double layer may also inhibit direct chemical interaction with material contained within the particle. By adjusting the REDOX potential of the fluid, through the addition or removal of electrons, it is often possible to weaken or eliminate the electrical double layer and thus promote agglomeration/flocculation and chemical interactions. It is also possible to damage cell walls of microbes, disrupt ion transport into and out of cells, and disrupt DNA bonds, leading to cell death.

To promote the disruption of chemical bonds, in addition to adding or removing electrons, it is also necessary to add energy. This energy flow may be significantly greater than that required to simply add or remove electrons, so some means is required to control energy flow independently of electron flow.

Typically, REDOX potential of a fluid is adjusted by adding chemicals such as acids, bases, salts, or other chemicals which disassociate into ions. If water is present, hydrogen (as hydronium) and hydroxide ions will be formed, altering the pH of the fluid. Once the desired chemical reactions occur, it then becomes necessary to use more and/or further additives to stop the reaction and/or to neutralize undesirable ions. In many instances, further processing is required to remove unwanted chemicals or constituents, generated during the neutralization process, from the desired end product.

When processing aqueous based fluids, by altering the REDOX potential through the addition or removal of electrons, the hydrogen ion concentration may be altered. In this manner, the equivalent of a pH shift can be achieved, without the addition of chemicals. However, because the counter ions may not be generated, chemical reaction pathways may differ at a given REDOX potential when compared to REDOX potentials achieved through chemical addition.

If DC current were to be forced to flow in a loop from cathode to anode, as would occur in a conventional electrolytic cell, there would typically be no net addition or removal of electrons. Thus, there would be no change in REDOX potential. To effect the desired change in REDOX potential, a means is required to add or remove electrons. Furthermore, when DC current flows through a conventional water based working fluid electrolytic cell, hydrogen gas is formed at the cathode and oxygen gas at the anode. This consumes a significant amount of energy. To minimize energy consumption, a means is required to add or remove electrons while minimizing the splitting of water into hydrogen and oxygen gas.

Summary

According to one aspect of the invention there is provided an apparatus, comprising: a vessel for containing a fluid to be treated; a variable DC voltage source; two or more electrodes disposed such that they contact the fluid in the vessel and are electrically connected to the variable DC voltage source; wherein the fluid is electrically isolated from ground except via an electrode; wherein the variable DC voltage source provides an output voltage that varies relative to ground.

In one embodiment the two or more electrodes are electrically connected to the variable DC voltage source such that one or more electrode is always a cathode and one or more electrode is always an anode. In one embodiment the two or more electrodes are electrically connected to the variable DC voltage source such that one or more first electrode is alternately a cathode for a first period of time and then an anode for a second period of time, and, simultaneously, one or more second electrode is alternately an anode for the first period of time and then a cathode for the second period of time.

In one embodiment the apparatus may comprise an electrical connection to ground via one or more anode electrode.

In one embodiment a waveform of the variable DC voltage has a positive voltage offset relative to ground greater than or equal to one-half of a waveform peak-to-peak voltage and less than the waveform peak-to-peak voltage.

In one embodiment the variable DC voltage varies within a range of about 1 volt and about 500 volts.

In one embodiment the voltage offset provides a minimum waveform voltage of negative 4.5 volts relative to ground.

In one embodiment a voltage applied to the cathode electrode is between negative 4.5 volts relative to ground and positive 500 volts relative to ground.

In one embodiment a voltage applied to the anode electrode is as low as negative 4.5 volts relative to ground.

In one embodiment the apparatus is used with an aqueous fluid to lower a pH of the fluid to a minimum of zero or less or to raise the pH to 14 or greater without the use of an additional chemical or agent.

In one embodiment the apparatus is used to increase electrode potential of the fluid to a more positive value or to lower the electrode potential of the fluid to a more negative value without the use of an additional chemical or agent.

In one embodiment the apparatus is used to add or remove electrons from the fluid.

In one embodiment the apparatus is used to increase conductivity of the fluid without the use of an additional chemical or agent such as an electrolyte.

In one embodiment the apparatus is used to precipitate at least one metal from the fluid. In one embodiment the apparatus is used to destroy or reduce or eliminate at least one biological contaminant in the fluid, or to destroy or reduce or eliminate toxicity of at least one chemical compound in the fluid.

In one embodiment the apparatus is used to kill, destroy, or render unviable at least one microorganism in the fluid.

Another aspect of the invention relates to a method for adjusting electrode potential of a fluid, comprising: containing the fluid within a vessel; exposing the fluid to two or more electrodes electrically connected to a variable DC voltage source, wherein the fluid is electrically isolated from ground; and applying a variable DC voltage that varies relative to ground to the two or more electrodes; wherein the electrode potential of the fluid is adjusted without use of an additional chemical or agent.

The method may comprise adjusting pH of the fluid, comprising providing an electrical connection to ground via the one or more anode electrode.

In one embodiment of the method, the waveform has a positive voltage offset relative to ground greater than or equal to one-half of a waveform peak-to-peak voltage and less than the waveform peak-to-peak voltage.

In one embodiment of the method, the variable DC voltage varies within a range of about 1 volt and about 500 volts.

In one embodiment of the method, the positive voltage offset provides a minimum waveform voltage of negative 4.5 volts relative to ground.

In one embodiment of the method, a voltage applied to the cathode electrode is between negative 4.5 volts relative to ground and positive 500 volts relative to ground.

In one embodiment of the method, a voltage applied to the anode electrode is as low as negative 4.5 volts relative to ground.

In one embodiment, the method lowers the pH of an aqueous fluid to a minimum of zero or raises the pH of an aqueous fluid to 14 or greater without the use of an additional chemical or agent. In one embodiment, the method increases electrode potential of the fluid to a more positive value or lowers the electrode potential of the fluid to a more negative value without the use of an additional chemical or agent.

In one embodiment, the method adds or removes electrons from the fluid.

In one embodiment, the method increases conductivity of the fluid without the use of an additional chemical or agent such as an electrolyte.

In one embodiment, the method comprises precipitating at least one metal from the fluid.

In one embodiment, the method comprises destroying, reducing, or eliminating at least one biological contaminant in the fluid, or destroying, reducing, or eliminating toxicity of at least one chemical compound in the fluid.

In one embodiment, the method comprises killing, destroying, or rendering unviable at least one microorganism in the fluid.

Brief Description of the Drawings

For a greater understanding of the invention, and to show more clearly how it may be carried into effect, embodiments will be described, by way of example, with reference to the accompanying drawings, wherein:

Fig. 1 is a block diagram of a generalized embodiment of the invention.

Fig. 2 is a schematic diagram according to an embodiment of the invention.

Fig. 3 is a schematic diagram according to another embodiment of the invention.

Fig. 4 is a schematic diagram according to another embodiment of the invention.

Fig. 5 is a schematic diagram according to another embodiment of the invention.

Fig. 6 is a schematic diagram according to another embodiment of the invention.

Fig. 7 is a schematic diagram according to another embodiment of the invention.

Fig. 8 is a schematic diagram according to another embodiment of the invention.

Fig. 9 is a schematic diagram according to another embodiment of the invention. Fig. 10 is a schematic diagram according to another embodiment of the invention.

Detailed Description of Embodiments

Many technologies have been proposed to overcome the limitations of the prior approaches noted above. The use of electrochemistry where DC current flows between electrodes is one example. This typically requires the addition of a chemical or agent which disassociates into ions to provide required conductivity of the fluid. Typically, in such prior approaches, the electrical power source is isolated from ground so while ions are generated, there is no net change in charge within the fluid. Thus, there is no net change in pH directly attributable to the electric current. Fluid energy levels (number of excited electrons where the term“excited electrons” refers to electrons which have moved from the ground state or valence band to the conduction band) can be increased utilizing such an approach, but cannot be reduced. Any changes to electrical conductivity of the fluid are minimal, apart from those associated with the added chemical or agent. An approach based on pulsed electromagnetic fields has also been utilized to disrupt bonds. Very high voltages are typically required for pulsed electrical fields (e.g., several thousand volts) and very high current flows are typically required for fluctuating magnetic fields. These technologies can be used to increase but not to decrease energy levels within a fluid. Also, they have no ability to alter pH. Finally, they have minimal effect on fluid conductivity. Thus, effects on electrical double layers are minimal. Radiation technologies which generate and apply high energy photons have also been used to disrupt bonds (ultraviolet radiation, for example). However, these approaches also do not change pH, can increase but not decrease fluid energy levels, and have minimal effect on conductivity.

Described herein are apparatus and methods that use radiant energy transfer to supplement conduction energy transfer to the fluid being processed. Embodiments provide cost- effective and safe control of REDOX potential of fluids while minimizing energy loss due to water splitting into hydrogen and oxygen gas.

For many chemical reactions, Pourbaix diagrams have been developed which indicate both the pH and the electrode potentials required to achieve specific end products. Embodiments described herein and variants thereof permit these parameters to be adjusted to meet the requirements indicated by the appropriate Pourbaix diagram, without adding additional chemicals or agents. This will apply to a wide range of chemical reactions, including reactions for the destruction of toxic compounds and drugs.

Embodiments use a direct current provided by a variable frequency/variable voltage power source to promote radiant energy transfer to supplement conductive energy transfer to the fluid via electric current. Without wishing to be bound by theory, it is suggested that the variable ffequency/variable voltage power source generates photons which transfer energy to electrons throughout the working fluid via radiant energy transfer through capacitive coupling, which supplements conduction energy transfer. Thus, energy transfer can occur into low

electrical/thermal conductivity fluids. The photons disrupt bonds within molecules to facilitate the formation of ions throughout the fluid. For example, water may be further disassociated into hydrogen and hydroxide ions. As the number of ions increases, conductivity of the fluid also increases. This facilitates the flow of electrons throughout the fluid which aids in the

disruption/formation of electrical double layers on particles (e.g., particulate matter, droplets, microorganisms) within the fluid. By adjusting the electrode potential of the fluid relative to the surface potential of particles being treated, the disruption/formation of electrical double layers on particles can be controlled.

As used herein, the term“ground” refers to an electrical ground, which is a zero-voltage reference level. A ground may also be referred to as a sink or a source, which can absorb or supply, respectively, electrical current without a change in electrical potential from zero volts. In practical application such as the embodiments described herein, a ground may approximate these characteristics.

As used herein, the term“fluid” refers to a liquid or a gas. Thus, embodiments described herein may be applicable to both liquids and gases.

As used herein, the term“electrode potential” is considered to be equivalent to“REDOX potential” and“EH”. In embodiments described herein, a voltage associated with a standard hydrogen electrode is assumed to be the zero voltage reference. Fluids with a higher availability of electrons would have a negative charge, and those with fewer electrons (more positive hydrogen ions) would have a positive charge.

Thus, if electrons are removed from a fluid, the concentration of hydrogen ions increases (where water is the working fluid), the REDOX potential becomes more positive, and the pH decreases. Conversely, if electrons are added, the REDOX potential becomes more negative as the added electrons neutralize the positive hydrogen ions and form negatively charged hydroxide ions, thus increasing the pH. When working with conventional chemistry, at a given fluid temperature, there is a direct correlation between REDOX potential and pH. However, when REDOX potential is changed due to electron addition/removal, the hydrogen ion concentration (pH) may not follow conventional pH calibration curves, and will be more dependent upon the band gap energies of contaminants within the water. With significant levels of complex contaminants, the associated relationship between REDOX potential (EH) and pH will be equivalently complex, requiring development of calibration curves specific to the application. Thus, when utilizing electron addition/removal technology, the use of pH for process control may prove less informative than using REDOX potential.

To destroy toxic compounds, it is first necessary to disrupt bonds within the compound. To do so, it is necessary to deliver sufficient energy to the bond site. When working with conductive fluids, the energy can be transferred from atom to atom utilizing either AC or DC current. However, with low conductivity fluids, radiant energy transfer may be required. This can be achieved using variable electromagnetic fields. The apparatus and methods described herein may be operated to deliver the energy required to disrupt bonds within both conductive and nonconductive fluids, while minimizing energy absorbed by the working fluid (through water splitting, as an example). To kill microorganisms, it is necessary to deliver energy to bond sites within the organisms, so as to disrupt these bonds and either kill the organism or prevent reproduction. Again, the apparatus and methods described herein may be operated to deliver the energy required to disrupt bonds within both conductive and nonconductive fluids, while minimizing energy absorbed by the working fluid. In many instances, it is desirable to remove or neutralize negatively charged particles or ions from polar solvents such as water or salt solutions. Often, this can be accomplished by increasing the electrode potential of the fluid. The apparatus and methods described herein may be operated to increase (i.e., make it more positive) the electrode potential within fluids, while minimizing energy absorbed by the working fluid. This will lower the pH of the fluid by forming hydrogen ions which will combine with the negative ions to form a neutral molecule. After the second hydrogen ion of a water molecule disassociates, an electrically neutral oxygen atom will remain. Two neutral oxygen atoms will then combine to form oxygen gas which will exit the fluid.

Conversely, if electrons are added (e.g., via a suitably located ground connection) the number of electrons within the fluid will increase, thereby decreasing the electrode potential (i.e., become more negative). The positive ions will“capture” electrons and become electrically neutral. This will reduce the concentration of positively charged ions, which will raise the pH of the fluid. As part of the process hydrogen ions will be neutralized and will bond together to form hydrogen gas which will exit the fluid.

Thus, according to embodiments, when working with aqueous fluids, the hydrogen ion concentration and the electrode potential can be adjusted. By controlling electrode potential (through electron addition/removal) hydrogen ion concentration in aqueous fluids can also be controlled. In this manner, a desired reaction (acid catalyzed reaction or base catalyzed reaction) may be promoted and then stopped upon achieving the desired end product, without the need to add additional chemicals or agents. This reduces the amount of chemicals required, reduces the amount of chemicals discharged to waste, improves product quality, and reduces processing costs.

Fig. 1 is a block diagram of a generalized embodiment. Referring to Fig. 1 , a vessel 10 contains a fluid 12 to be treated. First and second electrodes, which may be cathode and anode electrodes l4a and l4b, respectively, are disposed such that they are in contact with the fluid 12 in the vessel 10. The electrodes may be made of suitable materials, such as iron with an outer layer of nickel. A direct current source 16 that outputs a variable DC voltage (i.e., a DC voltage that varies, oscillates, or is pulsed relative to ground) is connected to the electrodes l4a and l4b. At least one of the amplitude of the variable voltage and the frequency of oscillation may be variable, or at least one of the amplitude and frequency may be fixed. The fluid in the vessel is electrically isolated from ground, except in embodiments where a ground connection is provided by one or more electrodes. For example, in the generalized embodiment of Fig. 1, the anode is connected to ground. In general, the circuit is connected to ground in a manner which permits electrons to be drawn from or delivered to ground. The direct current source 16 may provide a variable DC voltage having a selected waveform, and the waveform may have a voltage offset to ensure that the output voltage remains equal to or greater than the voltage of the ground connection. For example, the offset may provide a minimum voltage of - 4.5 volts relative to the ground connection. An actuator 18, such as a stirrer or a pump, may optionally be disposed in the vessel to promote circulation of the fluid between the electrodes l4a and l4b.

Embodiments include a DC power supply that provides a variable DC voltage to the electrodes, as noted above. The variable DC voltage may be an oscillating or pulsed DC voltage that is produced by, e.g., a half wave or full wave rectifier circuit, such as that used to rectify an AC voltage. In embodiments where the AC voltage is derived from the AC line voltage (e.g., via a transformer), such as the 60 Hz line voltage in North America, a half wave rectifier will provide a pulsed DC output voltage at 60 Hz (see, e.g., Fig. 3), and a full wave rectifier will produce a pulsed DC output voltage at 120 Hz (see, e.g., Fig. 2). Thus, the simplest way to implement the variable DC power supply is to use an unfiltered rectifier output. In other embodiments, the variable DC power supply may be implemented with circuitry that provides other waveforms, such as square waveforms, triangular waveforms, and saw tooth waveforms, and optionally allows for adjustment of parameters such as amplitude, frequency, and duty cycle of the waveforms. In other embodiments, an oscillating, cyclic, or pulsed DC voltage may be obtained by implementing a switch or switching network at the output of a DC power supply. Here, a filtered or substantially constant DC power supply can be used, or even a battery, since the switch or switching network can be operated to cycle or pulse the DC voltage on and off, or between two or more selected voltages. Such an embodiment allows for simple adjustment of the pulsed output frequency by controlling the switching frequency. In some embodiments the electrodes are connected to the variable DC voltage such that at least one first electrode is always an anode and at least one second electrode is always a cathode. In other embodiments the electrodes are connected to the variable DC voltage such that at least one first electrode and at least one second electrode oppositely alternate between anode and cathode. The at least one first electrode and the at least one second electrode may alternate between anode and cathode according to the pulsed frequency of the variable DC power supply. In various embodiments, the waveform peak-to-peak voltage may be within the range of about 1 volt to about 500 volts, or about 1 volt to about 250 volts, or about 1 volt to about 100 volts, or about 1 volt to about 24 volts, or about 1 volt to about 12 volts. Operation, according to an embodiment, will now be described with reference to Figs. 1 and 2. A fluid to be treated is placed in the vessel 10. The hydrogen ion concentration of the fluid 12 in the vessel 10 is then adjusted. To increase the hydrogen ion concentration and thus lower pH, electrons are removed as required. This is accomplished by using the direct current source 16 to apply a variable voltage between electrodes l4a, l4b, which may be configured as concentric cylindrical electrodes, and connecting the anode directly to an electron sink such as ground. Optionally, to enhance efficiency, a non-conductive cathode may be utilized as shown in Fig. 9. The actuator 18 may be used to direct the fluid to flow between the electrodes l4a, l4b. The schematic diagram of Fig. 2 shows a circuit configuration.

Referring to Fig. 2, a direct current source is implemented using a variable

frequency/voltage AC source 20 connected to a transformer primary side windings 22a, 22b (which may also be a single continuous winding), with the transformer secondary side windings 24a, 24b and center-tap 24c connected to a full-wave rectifier including diodes 26a, 26b. The use of a transformer advantageously isolates the output circuit (secondary side) from the main source of power (primary side), thus limiting the risk of uncontrolled high energy electrical discharge. The transformer also reduces current loading within the AC source which may reduce overall cost of the direct current source. The anodes of the diodes are connected together and to the cathode electrode (-). The transformer center-tap 24c is connected to the anode electrode (+), and optionally connected to ground. Thus, in this embodiment, the waveform of the variable voltage applied to the electrodes is a half sine wave having a minimum voltage of zero volts and a maximum (i.e., peak voltage) determined by setting the AC input voltage at the variable AC source 20. In some embodiments, the maximum voltage is 12 volts peak or less. Low voltages in the range of about 12 volts peak are suitable for most applications. For example, in some embodiments, the maximum voltage is 6 volts peak or less. However, higher voltages may be used in applications where the goal is to disrupt very strong bonds. The use of higher voltages may result in currents greater than the rating of the transformer, particularly as the pH moves further from 7 and the fluid becomes more conductive, requiring appropriate design

considerations. The schematic diagram of Fig. 5 shows another circuit configuration which is similar to that of Fig. 2, with multiple parallel plate type electrodes and without a ground connection at the anode. This configuration may be used to add electrons. The variable voltage may be achieved by providing a direct current output in a selected waveform. The waveform may be a half sine wave, a full sine wave, a square wave, a saw tooth wave, etc. The frequency may be in the range of 1 Hz to about 300 MHz. The shape of the waveform is not critical, although certain process conditions may be optimized by selecting a certain waveform or frequency. The waveform may be provided with a voltage offset equal to or greater than half the peak-to-peak voltage so that the voltage on the anode never drops below ground potential (i.e., zero volts). Suitable circuit diagrams for alternative waveforms are not shown, as these will be readily apparent to those of ordinary skill in the art. Good results may be achieved with a single cathode electrode surrounded by the anode electrode, as shown in Fig. 2. However, greater numbers of anodes and cathodes may be used in this embodiment and other embodiments described herein, or variants thereof.

For example, using the configuration of Fig. 2 with water as the fluid, a pH of less than 0 and electrode potentials exceeding +760 mV as measured within the vessel or +400 mV as measured when isolated have been achieved using a peak to neutral voltage supplied to the rectifier in the order of 6 volts rms. At the primary side of the transformer the input voltage was approximately 120 volts AC at a frequency of 60 Hz (i.e., the line voltage and frequency), and the input current was in the order of 1 A (as measured using a simple amp meter), which is an approximation due to the high ripple produced by the rectification circuit. The output frequency was double the line frequency (120 Hz). Other configurations which result in electron removal may be utilized.

When removing electrons from aqueous fluids, the theoretical minimum negative cathode voltage required to reduce the pH to a specified value is in the order of -(1.229 - pH x 0.0592) volts, where pH is the desired pH of the process fluid. Note that the peak voltage must be adjusted higher (i.e., more negative) to overcome various resistance losses and provide desired current flow. However, if the voltage is adjusted significantly higher, energy will be wasted through the production of excess oxygen. Thus, it is desirable to monitor the current. This may be done using any suitable method, although a measurement technique should not be confounded by factors such as voltage reflection caused by the diodes, standing waves in the circuit, etc., and should be capable of measuring current at frequencies in the order of 300 MHz. The maximum current will of course be limited by the maximum current capability of the electrical power supply equipment used, but also upon the type of electrode used and the application. As an example, for the chloralkali process, a maximum recommended current density would be in the order of 0.4 amps per square centimeter of electrode contact surface area to prevent excessive erosion of the iron/nickel electrodes used. Non-aqueous fluids require different voltages to generate equivalent positive ion concentrations, but in many instances they behave similarly. Note also that for optimal control, the fluid should remain electrically isolated from electron sources or sinks except for contact with the electrodes.

Conversely if it is necessary to raise the pH, electrons may be added as required. For example, according to the embodiments shown in Figs. 3 and 4, this may be accomplished by applying a variable voltage between the electrodes l4a, l4b using a power supply where the current inlet (i.e., the positive terminal) is connected to ground (or some other electron source other than the fluid), optionally through a device, such as a resistor 38, as shown in Fig. 3. The embodiment of Fig. 3 includes a variable AC source 20 connected to a transformer primary side windings 32a, 32b. The transformer secondary side windings 34a, 34b are connected to a full- wave rectifier including diodes 36a, 36b. The cathodes of the diodes are connected together and to the resistor 38. The resistor (or other device) 38 may be variable, which can be used to cause a voltage drop in the range of about, e.g., 0 - 2 volts. A pump or other actuator (e.g., 18 in Fig. 1) may be used to direct the fluid to flow between the electrodes. Good results were achieved with multiple anode electrodes and multiple cathode electrodes located between the anode electrodes, as shown schematically in Fig. 3. Several experiments were run using this configuration with water and pH values in excess of 14 were attained. The electrode potentials at 14 pH were in the order of -570 mV as measured within the vessel or -400 mV as measured when isolated. The minimum theoretical voltage drop required across the combined inlet resistance (i.e., variable resistor 38 + diodes 36a, 36b) applied to the cathode l4a is in the order of (pH x 0.0592) volts where pH is the desired pH of the process fluid. A significantly greater voltage drop will tend to waste energy through the production of excess amounts of hydrogen gas, and will tend to reduce reaction rates by reducing current flow. The maximum voltage applied to the cathode must be positive relative to ground for direct current to flow (i.e., a higher electron concentration on the cathode than on the anode). Note that the actual working voltage can be adjusted higher to overcome various resistance losses and provide desired current. The desired current will be based upon acceptable electrode erosion levels as discussed above. Non-aqueous based fluids require different voltages but in many instances they behave similarly. Note again that the process fluid must remain electrically isolated from electron sources or sinks except for contact with the electrodes.

Other configurations which result in electron addition may be utilized. For example, in the embodiment shown in Fig. 4, both secondary windings 44a, 44b of the transformer are connected in phase. This doubles the peak current available to the cathode l4a and does not double the frequency (as in the embodiment of Fig. 3), resulting in an output voltage that varies cyclically at the line frequency (e.g., 60 Hz).

Fig. 6 shows an alternative embodiment implemented with a variable AC power supply, a transformer having a center-tapped secondary winding 64a, 64b, and diodes 66a, 66b to provide a variable DC current, and an inductor 68 connected in parallel with the electrodes l4a, l4b used to treat the process fluid. This configuration forms a harmonic oscillator (i.e., a resonant circuit including the inductor 68 and the electrodes) which increases photon flow between the electrodes l4a, l4b, thereby providing a significant increase in energy transfer to the process fluid. The resonant circuit allows the electrodes l4a, l4b to oppositely alternate between anode and cathode at the resonant frequency, with the electron charge on the electrodes remaining more negative than ground.

Fig. 7 shows an alternative embodiment similar to that of Fig. 6, which includes the resonant circuit of inductor 68 and the electrodes l4a, l4b, and is implemented with a second variable DC power supply, including variable AC source 20b, primary winding 72, center-tapped secondary winding 74a, 74b, and diodes 76a, 76b, connected between the anode electrode l4b and the ground connection. The second power supply is used to lower the anode electrode potential. This increases the voltage potential between the process fluid and the anode which enhances energy transfer from the fluid to the anode and from there to ground, and allows the electrode potential of the process fluid to be reduced below ground potential. This significantly enhances the ability to precipitate metals from the fluid. In this embodiment the anode electrodes are not directly connected to ground. As in the embodiment of Fig. 6, the resonant circuit allows the electrodes l4a, 14b to oppositely alternate between anode and cathode at the resonant frequency.

Fig. 8 shows an alternative embodiment which may be used to lower the REDOX potential of the treatment fluid, making it more negative. This embodiment is implemented with a variable DC power supply including variable AC source 20, primary winding 82, center-tapped secondary winding 84a, 84b, and diodes 86a, 86b, with the electrodes l4a, l4b connected between the diodes. A DC power supply 87 is connected between the transformer center-tap and ground to provide a DC voltage offset. Using an implementation based on this embodiment, it is possible to add both energy (via variable EM field) and electrons to the fluid without having electrons exit the fluid. With this embodiment, "current X resistance" losses (IR losses) are minimized. Also, because electrons cannot exit (neither of the electrodes serves as an anode due to the presence of opposing diodes86a, 86b) oxygen gas is not released. Thus, minimal energy is expended splitting water molecules into hydrogen and oxygen (the splitting of water is typically not required for treating contaminants within the water, thus any energy so spent is wasted). Furthermore, by trapping electrons within the fluid, it is possible to lower the REDOX potential to a greater extent than would typically be possible should the anode be directly connected to ground. This may permit treatment of contaminants which cannot be accomplished at higher (less negative) REDOX levels. It is noted that the DC power supply 88 is optional but in many applications it improves system performance.

The embodiment of Fig. 9 is implemented with a variable DC power supply including variable AC source 20, primary winding 92, center-tapped secondary winding 94a, 94b, and diodes 96a, 96b. A DC power supply 97 is connected between the transformer center-tap and ground to provide a DC voltage offset. The electrodes are implemented with an anode 90a and a cathode 90b. However, the cathode is coated with a material which is non-conductive with regards to electron flow, and does not absorb energy from the variable EM field at the energy levels being utilized. The accumulation of electrons on the cathode causes electrons within the fluid to move to the anode and exit to ground. The loss of electrons increases the REDOX potential of the fluid (i.e., makes it more positive). Again, as there is no flow of electrons from the cathode to the anode, minimal water splitting occurs which in turn minimizes IR energy loss. Finally, because there is no inflow of electrons, the REDOX level can be elevated (more positive) beyond the levels which can typically be achieved with conventional DC circuits utilizing conductive anodes and cathodes. This may permit promotion of higher energy chemical reactions than could otherwise be achieved. The DC power supply 98 is optional but may improve system performance in some applications. The embodiment of Fig. 10 combines features of the embodiments of Figs. 6 and 8. This embodiment includes a variable DC power supply implemented with variable AC source 20, primary transformer winding 102, center-tapped secondary winding l04a, l04b, and diodes l06a, l06b, and includes a DC power supply 107 connected between the diodes and ground to provide a DC voltage offset. An inductor 108 is connected in parallel with the electrodes lOOa, lOOb. This configuration allows the secondary windings to be part of the resonant LC circuit. As in the embodiments of Figs. 6 and 7, the resonant circuit allows the electrodes lOOa, lOOb to oppositely alternate between anode and cathode at the resonant frequency.

It will be appreciated that embodiments based on the description presented herein may be configured and used to treat fluid samples such as water, to create conditions required to kill or destroy, or render unviable a wide range of microorganisms including, for example, bacteria, oocysts, and prions, to destroy or reduce toxicity of biological compounds and organic contaminants, and to promote sedimentation of particulate matter and to precipitate heavy metals and various compounds such as calcium carbonate.

The invention is further described by way of the following non-limiting examples.

Working Example 1

An embodiment was built and used to promote sedimentation of particulate matter and to precipitate heavy metals in a fluid sample (an oil field produced water sample containing the metals and approximately 22,000 ppm sodium (as sodium chloride)).

A pipe-in-pipe electrode configuration was used with a 41 mm outside diameter stainless steel inner electrode and a 52.5 mm inside diameter stainless steel outer electrode.

Approximately 15 L of the fluid was added to a vessel. Power was supplied to the electrodes using a circuit as shown in Fig. 2, with a DC pulse amplitude of 4.5 volts at a frequency of 120 Hz. The fluid was circulated between the electrodes until the pH of the fluid reached 1. The pH was measured using a REED Model SD-230 pH/ORP (oxidation/reduction potential) meter. Treatment was then ceased and the fluid left to set for 12 hours. A sample was drawn from the top of the vessel (without disturbing material which had settled to the bottom) and sent, along with an untreated sample of the starting fluid, to an independent lab for analysis.

Without process optimization, metal content was reduced as follows:

Aluminum from 12 ppb to 1 ppb;

Barium from 46 ppm to 7 ppm;

Iron from 80 ppb to 16 ppb;

Manganese from 130 ppb to 2 ppb;

Phosphorus from 29 ppb to 6 ppb;

Silicon from 9.8 ppm to 4 ppm;

Sulphur from 8.1 ppm to 0 ppb;

Tin from 2 ppb to 0 ppb;

Working Example 2

An embodiment was built and used to kill or destroy microorganisms. The fluid sample was a microbial contaminated fluid sample in which the microbes were total coliform bacteria.

Approximately 15 L of the sample were placed in a vessel. Mild steel parallel plate electrodes were used with a gap spacing of approximately 5 mm. Power was supplied to the electrodes using the circuit configuration shown in Fig. 4, with a DC pulse amplitude of 4.5 volts at a frequency of 60 Hz. The fluid was circulated between the electrodes until the pH reached 11.5. The pH was measured using a REED Model SD-230 pH/ORP meter.

A sample of the untreated starting fluid and two samples of the treated fluid were taken to an independent lab for analysis. The untreated fluid sample was plated and was completely overgrown with colonies, making it impossible to obtain a plate count. For the treated fluid samples, plating resulted in three colonies in one sample and one colony in the second sample.

All cited publications are incorporated herein by reference in their entirety. Equivalents

While the invention has been described with respect to illustrative embodiments thereof, it will be understood that various changes may be made to the embodiments without departing from the scope of the invention. Accordingly, the described embodiments are to be considered merely exemplary and the invention is not to be limited thereby.