WO1994010836A1

WO1994010836A1 - Control of undesirable organisms

Info

Publication number: WO1994010836A1
Application number: PCT/US1993/010916
Authority: WO
Inventors: B. Newton Gossett; Joel S. Gosset
Original assignee: Aqua Motion, Inc.
Priority date: 1992-11-16
Filing date: 1993-11-10
Publication date: 1994-05-26
Also published as: AU5601594A

Abstract

A method and apparatus for producing a composition for control of organisms that are dependent, directly or indirectly, upon nitrogen fixation is disclosed in which the effective control ingredient of the composition is molybdenum or tungsten ions. Such metal ions, for example produced in water, are toxic to pests such as termites or shipworms. The apparatus includes an electronic circuit (62) that periodically reverses current to electrodes (56, 58) made of molybdenum, tungsten, or alloys thereof, the electrodes (56, 58) being positioned adjacent to a conduit (28) for conducting water therethrough.

Description

Control of Undesirable Organisms

Field of the Invention This invention relates to apparatus, methods and compositions for the control of organisms, and, more particularly, relates to control of organisms that are capable, directly or indirectly, of nitrogen fixation.

Background of the Invention Great effort has been historically directed to development of compositions, apparatus and methods for controlling undesirable plant and/or animal life (as used herein, collectively referred to as "organisms") . Prior compositions for controlling termites, shipworms or the like, for example, have included a wide variety of compounds that can be impregnated in cellulose (typically wood) to prevent infestation or directly eradicate such pests.

These compounds have included organic insecticides (such as DDT, dieldrin, chlordane, parathion, and alathion) or other toxic substances incorporated in a bait or attractant (for example, various cellulose extractions) used in mixtures to saturate wood, or the area around wood, to thus control the pest. In some cases, the environmental toxicity of these materials has reduced their application. Some such compounds have even been banned by the U.S. Environmental Protection Agency (EPA) . Baits, traps, and other devices and methods have also been suggested for control of undesirable organisms, and in some cases are utilized in association with various insecticides or the like. Various metallic compounds have been heretofore suggested and/or utilized in wood preservatives, fungicides, and/or insecticides and the like, such compounds including chromated zinc chloride, chromated zinc sulfate, copper sulphate, arsenic compounds, and mercury compounds (U.S. Patent Nos. 2,784,139 and 2,886,486), hexavalent chromium (U.S. Patent No. 3,832,463), alkali metal cyanide with a liquid fungicide which includes mercury, lead, tin, copper, or zinc (U.S. Patent No. 3,993,752), azide and metal salts of iron, aluminum, nickel, manganese, cobalt, zinc, tin and magnesium (U.S. Patent No. 4,132,780), nickel salts (U.S. Patent No. 3,214,332), boron compounds (U.S. Patent No. 4,363,798), and hexachlorocyclopentadiene dimer in organic solvent carrier (U.S. Patent No. 3,858,346). In particular, various molybdenum or tungsten compounds have heretofore been suggested and or utilized for bacteriological and/or pesticidal uses (see U.S. Patent Nos. 2,025,405, 3,290,343, 3,317,571 and 4,504,468). For example, U.S. Patent No. 4,504,468 teaches use of a composition of molybdenum or tungsten salts to control pests which are indirectly capable of nitrogen fixation, such as termites or shipworms, the composition being used with termite baits, soil inoculants, or other ingredients for preserving wood by dipping or pressure treatment. As discussed therein, termites, shipworms and the like are not directly capable of nitrogen fixation, but are dependent upon a symbiotic relationship with bacteria or protozoa residing in the gut of the animal which are capable of nitrogen fixation. The protozoa or bacteria thus produce nitrogen necessary for the animal in the synthesis of protein, and are therefore essential to the nutrition of termites and other similar animals (cellulose being devoid or low in nitrogen) .

The various molybdenum or tungsten compounds heretofore suggested, however, have not always proved easy to apply and/or have been applicable only in particular environments, these compounds requiring off- site formulation, specialized handling and/or application techniques.

Various devices and methods have heretofore been suggested for controlled release of insecticides (see U.S. Patent Nos. 3,909,975, 3,940,875, 4,625,474 and 3,911,611), such devices typically relying on various carriers or the like and being in the nature of immovable installations. Devices utilizing systems of electrolysis for algae, bacteria and/or protozoan life in bodies of water have also been suggested (see U.S. Patent Nos.

4,257,352 and 3,891,535), at least one of these systems utilizing active addition of metal ions to the water (see U.S. Patent No. 3,752,747). Such systems have suggested, however, use of either inert electrodes, or copper or aluminum electrodes, and have thus required some sort of monitoring technique and/or limited the potential application sites in order to maintain safe utilization. Further improvement in the art of control of undesirable organisms could thus still be utilized.

Summary of the Invention This invention provides a composition, method and apparatus for control of undesirable organisms, and particularly such organisms which are capable, either directly or indirectly, of nitrogen fixation. The invention is environmentally safe, easy to use, and is applicable in numerous situations and environments, the composition being capable of formulation either on or off the site of application and requiring no specialized formulation, handling, application or monitoring techniques.

The composition includes molybdenum cations, tungsten cations, and/or cations produce from alloys, compounds or mixtures including molybdenum or tungsten, in fluid (preferably water) , and is particularly effective for controlling termites, shipworms and other such organisms.

The apparatus includes an electrode for producing ions at a part thereof, the electrode being made of molybdenum, tungsten or alloys including molybdenum or tungsten, and being mounted in a conduit having an inlet and an outlet for conducting liquid into and out of the conduit. A control unit is connected with the electrode for applying a voltage thereto.

The apparatus preferably includes first and second electrodes mounted at the conduit between the inlet and outlet for distribution of cations in the liquid stream as it passes between the inlet and outlet. The control unit may include a current reversing circuit for reversing current applied to the electrodes to prolong electrode life. In use, molybdenum or tungsten cations are produced in the fluid, after which the organisms to be controlled are exposed to the ionized fluid.

It is therefore an object of this invention to provide an improved composition, method and apparatus for control of undesirable organisms.

It is another object of this invention to provide for control of undesirable organisms which are capable, directly or indirectly, of nitrogen fixation.

It is still another object of this invention to provide a composition, method and apparatus for control of undesirable organisms which are environmentally safe, easy to use, and are applicable in numerous situations and environments, the composition being capable of formulation either on or off the site of application and requiring no specialized formulation, handling, application or monitoring techniques.

It is yet another object of this invention to provide a method for control of pests by producing cations of molybdenum and/or tungsten in water in areas, or to be applied to areas, infested with, or susceptible to infestation by, termites or shipworms.

It is another object of this invention to provide an apparatus for control of undesirable organisms including an electrode for producing ions at a part thereof, the electrode being made of molybdenum, tungsten, or alloys including molybdenum or tungsten, means for applying voltage to the electrode, and a conduit having an inlet and an outlet for conducting liquid into and out of the conduit and configured to receive the part of the electrode for distribution of ions between the inlet and the outlet.

It is still another object of this invention to provide an apparatus for control of organisms capable, directly or indirectly, of nitrogen fixation including first and second electrodes made of molybdenum or alloys including molybdenum, means for applying a voltage to the electrodes, a current reversing circuit connected with the voltage applying means for reversing current applied to the electrodes, and a conduit having an inlet and an outlet for conducting liquid into and out of the conduit and configured to receive a part of each of the electrodes for distribution of cations in the liquid between the inlet and outlet.

It is yet another object of this invention to provide a method for control of undesirable organisms including the steps of producing molybdenum cations or tungsten cations in a fluid and exposing the organisms to the cations in the fluid.

It is still another object of this invention to provide a composition for control of organisms capable, directly or indirectly, of nitrogen fixation consisting essentially of a fluid having molybdenum ions and/or tungsten ions dispersed therein.

With these and other objects in view, which will become apparent to one skilled in the art as the description proceeds, this invention resides in the novel construction, combination, arrangement of parts, composition and method substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that changes in the precise embodiment of the herein disclosed invention are meant to be included as come within the scope of the claims.

Brief Description of the Drawings The accompanying drawings illustrate a complete embodiment of the apparatus of this invention according to the best mode so far devised for the practical application of the principles thereof, and in which:

FIGURE 1 is a perspective view of the apparatus of this invention;

FIGURE 2 is a sectional view taken through section lines 2-2 of FIGURE 1; and

FIGURE 3 is an electrical block diagram of the control unit of the apparatus of FIGURE 1. Description of the Invention Referring now to the FIGURES, the apparatus of this invention includes control unit 10 connected with ionization unit 12. Control unit 10 is connectable with a power supply module 14 (as represented in FIGURE 3) or may have its own built in power supply, and includes output current control knob 16 (for example a potentiometer or variable resistor) , digital LED readout display 18, power supply input connector 20 and output connector 22 including connecting wires 24 and 26.

As illustrated in FIGURE 2, unit 12 includes conduit 28 having inlet 30, outlet 32 and side channels 34 and 36. Conduit 28 may be made, for example, of 1.5 to 4 inch or larger PVC tubing constructed, generally, in a tee- shaped configuration. Threaded adaptors 38 and 40 (made for example of PVC) are secured in side channels 34 and 36, respectively, and have male plugs 42 and 44 (again made, for example, of PVC) threadable thereinto.

Plugs 42 and 44 each have a recessed area 46 defined between plug wall 48 and fitting head 50. Screws 52 (made of conductive material) are accommodated in a sealing relationship through plug wall 48 of each of plugs 42 and 44, holding spade lug connectors 54 at one side of walls 48 for connection with connecting wires 24 and 26 at different ones thereof, and sealed into electrodes 56 and 58.

Electrodes 56 and 58 are made of substantially pure molybdenum, tungsten, or alloys thereof (for example, molybdenum with tungsten, molybdenum with copper, tungsten with copper, molybdenum with silver, tungsten with silver, or combinations of these materials, with each electrode not necessarily being made of the same material as the other) . The electrodes may be made of one inch diameter rod, though other sizes and configurations (for example, point source electrodes) may be appropriate for various applications, and are of a length so as not to extend into flow pathway 60 through conduit 28 between side channels 34 and 36.

Inlet 30 and/or outlet 32 of conduit 28 may include fittings for adaptation of unit 12 to various applications, such as hose fittings, nozzles, spray heads, pumps for use with still bodies of water, or the like.

FIGURE 3 illustrates one possible arrangement of components for the power supply and control unit of the apparatus of this invention. It should be realized, however, that other arrangements could be utilized depending on use of the apparatus, availability of AC power supply (for example, solar powered or conventional battery powered units could be utilized) , voltage and current requirements (for example, it may be possible to use a single electrode arrangement with substantially increased voltage to the electrode and with very limited amperage, a point source electrode being more likely in such a case) , and the like. Power supply module 14 is connected to a standard 115 volt AC source, converting and rectifying the AC signal to provide a 24 volt DC signal at about 400 itiA at its output to control unit 10. Control unit 10 receives the DC output from power module 14 at off/on and current control circuit 60 for controlling the current output therefrom, either continuously or in steps of about 20 mA, to electrodes 56 and 58.

The signal from circuit 60 is received at reversing circuit 62 including timer 64 for periodically reversing current to the electrodes at selected intervals (for example, about every 18 seconds) , thus reversing polarity of each of the electrodes thereby prolonging the life of the electrodes. The output from control unit 10 is coupled with electrodes 56 and 58 through connecting wires 24 and 26 for ionization of fluid passing through conduit 28 by electrolysis.

It has been found that molybdenum and/or tungsten cations in water are effective in killing all manner of nitrogen fixing bacteria and algae (blue-green algae) , as well as certain fungi and animals having a symbiotic relationship with nitrogen fixing bacteria or the like, such as termites, shipworms, and/or certain protozoa serving as hosts. In the case of molybdenum electrodes, for example, the log K values for molybdenum ((Mo) +3) indicate that it can be effectively ionized, which indications have been shown by applicant's testing. A five volt signal at 50 milliamperes ( a) supplied to electrodes 56/58 (having for purposes of this example seven square inches of electrode surface) will produce about 36 ppm of molybdenum in water at a flow rate of about 600 milliliters per hour ( l/hr) through conduit 28. The cumulative production of molybdenum cations at different rates or accumulation in soil or wood can be increased respectively with time and/or electrode surface area. Thus, with 5.0 volts DC, 50 ma and 68 square inches of electrode surface area in 600 ml of still water, or water flowing at an equivalent rate, 350 ppm of molybdenum will be produced in one hour. Testing indicates that relatively low rates of molybdenum thus produced in water (as little as up to about 350 ppm) substantially reduces the number of bacterial flora in the gut of termites.

Since the termite requires a symbiotic relationship with these intestinal microflora to digest cellulose, killing the nitrogen fixing bacteria will kill the termite (usually in about 17 days) . It has also been found that termites will readily accept molybdenum in their diet.

Molybdenum is considered an essential trace element in humans, and has been shown by various agencies to have little or no toxicity in humans at levels of 9.5 mg/1. Little evidence has yet been presented regarding an upper limit of safe human intake of molybdenum. Indications are that the use of molybdenum as a termiticide, or in other such applications, would have no toxic effects on humans. Neither the National Academy of Science (NAS) nor the World Health Organization (WHO) have recommended a limit for molybdenum in drinking water. It is thus felt that dosages of between about 3,500 and 5,000 ppm molybdenum in water would be both effective and safe (research has not yet been conducted indicating at what level maximum effectiveness is achieved) .

In use, ionization unit 12 is attached to a source of moving fluid and control unit 10 is activated. Settings are selected to produce the level of ion content desired (which may be indicated at readout 18) . If desired, a fitting for selected distribution of ionized water is attached to output 32 of conduit 28, and soil, wood or other surfaces or structures to be treated are exposed to the effluent from ionization unit 12. Alternatively, the effluent may be captured, stored and later applied at a site elsewhere.

Fluid ionized as heretofore set forth can be produced on site in either flowing or still water, or can be produced off site for transportation to and use in the affected area. Since the composition and related method and apparatus of this invention are thought to be relatively safe (both environmentally and in use) , a wide variety of other applications is anticipated, including in the treatment of root fungus in vineyards and farm fields, purification of watering tanks and/or ponds, livestock cleaning, greenhouse and/or home lawn and garden applications, HVAC cleaning and purification, aquarium cleansing, pool cleaning, sewage effluent treatment, and perhaps even in the treatment of drinking water.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for control of undesirable organisms comprising: electrode means for producing ions at a part thereof, said electrode means being made of one of molybdenum, tungsten, and alloys including at least one of molybdenum and tungsten; voltage applying means connected with said electrode means for applying a voltage to said electrode means; and a conduit having an inlet and an outlet for conducting liquid into and out of said conduit and configured to receive said part of said electrode for distribution of ions between said inlet and said outlet.

2. The apparatus of claim 1 wherein said electrode means includes molybdenum.

3. The apparatus of claims 1 or 2 wherein said electrode means includes first and second spaced electrodes.

4. The apparatus of claim 3 wherein said voltage applying means applies signals of opposite polarity to said first and second electrodes.

5. The apparatus of claims 3 or 4 further comprising current reversing means connected with said voltage applying means for periodically reversing the current to said electrodes.

6. An apparatus for control of organisms capable, directly or indirectly, of nitrogen fixation comprising: first and second electrodes made of one of molybdenum and alloys including molybdenum; voltage applying means connected with said electrodes for applying a voltage to said electrodes; a current reversing circuit connected with said voltage applying means for reversing current applied to said electrodes; and a conduit having an inlet and an outlet for conducting liquid into and out of said conduit and configured to receive a part of each of said electrodes for distribution of cations in said liquid between said inlet and said outlet.

7. The apparatus of claim 6 wherein said alloys are one of molybdenum-tungsten alloy, molybdenum-silver alloy, molybdenum-copper alloy and combinations thereof.

8. The apparatus of claims 6 or 7 wherein said electrodes are configured for, in conjunction with said applied voltage, production of at least about 350 ppm of molybdenum in said liquid.

9. The apparatus of claims 6 through 8 wherein said conduit includes a primary channel having said inle and said outlet at opposite ends thereof and first and second side channels opening into said primary channel and having said electrodes therein.

10. The apparatus of claim 9 wherein said side channels are configured for receipt of said electrodes therein so that said parts of said electrodes do not protrude into said primary channel.

11. The apparatus of claims 6 through 10 wherein said current reversing circuit includes a timer for selective periodic current reversal.

12. The apparatus of claims 6 through 11 further comprising a control unit connected with said voltage applying means for controlling current applied to said electrodes.

13. A method for control of undesirable organisms comprising the steps of: producing at least one of molybdenum ions and tungsten ions in a fluid; and exposing said organisms to said ions.

14. The method of claim 13 wherein the step of producing ions includes the step of applying a voltage to an electrode made of one of molybdenum, tungsten, and alloys including at least one of molybdenum and tungsten.

15. The method of claims 13 or 14 further comprising the step of producing said ions in a flowing stream of water by electrolysis.

16. The method of claims 13 through 15 wherein said ions are cations.

17. The method of claim 16 wherein the step of producing cations in fluid includes producing at least up to about 350 ppm of molybdenum at a site where organisms are to be exposed.

18. The method of claims 13 through 17 wherein the step of exposing said organisms includes the step of one of pressure spraying an area having said organisms therein, spraying an area having said organisms thereon, flowing said liquid to an area having said organisms thereat, and producing said cations in a body of liquid having said organisms therein.

19. The method of claims 13 through 18 wherein the step of producing ions in fluid includes producing said ions in fluid at the site of, and at the time of, exposure of said organisms.

20. The method of claims 13 through 19 wherein the organisms are one of termites and shipworms.

21. A composition for control of organisms capable, directly or indirectly, of nitrogen fixation consisting essentially of a fluid having at least one of molybdenum ions and tungsten ions dispersed therein.

22. The composition of claim 21 wherein said fluid is water.

23. The composition of claims 21 or 22 wherein said ions are molybdenum cations.

24. The composition of claims 21 through 23 wherein said ion content is at least about 350 ppm in said fluid.