MITCHELL, Stephen, R. (1219 Minnesota Avenue, Natrona Heights, PA, 15065, US)
| WHAT IS CLAIMED IS:
1. A method for treating a PCB-contaminated surface, comprising the steps of:
(a) preparing a pollution remedial composition;
(b) heating the pollution remedial composition; and
(c) spraying the pollution remedial composition onto the surface.
2. The method of claim 1 , wherein the pollution remedial composition comprises more than 35 volume % but less than 40 volume % of a soluble silicate; from about 0.25 to about 5 volume % of a surfactant; from about 1 to about 5 volume % of a polyol; and the remainder water.
3. The method of claim 1 , wherein the pollution remedial composition is heated to a temperature of between about 120 0 F and 130 °F.
4. The method of claim 1 , wherein the PCB-contaminated surface comprises a coating on a substrate and the coating is comminuted or dissolved by the sprayed composition.
5. The method of claim 1 , including spraying the pollution remedial composition onto the surface at a spray pressure from about 1000 psi to about 3500 psi.
6. The method of claim 2, wherein the pollution remedial composition further comprises a foaming agent.
7. A method for treating a PCB-containing oil, comprising the steps of:
(a) preparing an aqueous pollution remedial composition comprising more than 35 volume % but less than 40 volume % of a soluble silicate; from about 0.25 to about 5 volume % of a surfactant; from about 1 to about 5 volume % of a polyol; and the remainder water; and (b) mixing the aqueous pollution remedial composition with the PCB- containing oil to form an emulsion in which the pollution remedial composition destroys the PCB compounds.
8. The method of claim 7, wherein the volume ratio of the aqueous pollution remedial composition to the PCB-containing oil is about 1:1.
9. The method of claim 7, wherein the volume ratio of the aqueous pollution remedial composition to the PCB-containing oil is in the range from about 2:1 to about 5:1.
10. A pollution remedial composition that foams on application comprising more than 35 volume % but less than 40 volume % of a soluble silicate; up to about 2.5 volume % of a surfactant; from about 1 to about 5 volume % of a polyol; from about 0.25 to about 5 volume % of a foaming agent, and the remainder water.
11. A method for treating a PCB-contaminated surface, comprising the steps of:
(a) preparing a foaming pollution remedial composition; and
(b) applying the foaming pollution remedial composition onto the surface under pressure to produce a foamed pollution remedial composition on application.
12. The method of claim 11, wherein the surface is a generally vertical surface.
13. The method of claim 11 , wherein the surface is an overhead generally horizontal surface.
14. A method for treating a PCB-contaminated source, comprising the steps of:
(a) preparing a pollution remedial composition;
(b) heating the PCB-contaminated source to vaporize PCBs in the source;
(c) condensing the vaporized PCBs;
(d) collecting the condensate; and (e) mixing the condensate with an amount of the pollution remedial composition sufficient to destroy the PCB compounds.
15. The method of claim 14, wherein the source is soil.
16. The method of claim 14, wherein the pollution remedial composition comprises more than 35 volume % but less than 40 volume % of a soluble silicate; from about 0.25 to about 5 volume % of a surfactant; from about 1 to about 5 volume % of a polyol; and the remainder water.
17. The method of claim 1 , wherein the PCB-contaminated surface is concrete.
18. The method of claim 17, further comprising prior to step (a) drilling core holes into the concrete surface.
19. The method of claim 18, wherein the core holes have a 1 inch diameter and a depth of at least about 6 inches.
20. The method of claim 18, wherein the core holes are spaced at about 10 inches from one another.
21. A method for treating a PCB-containing material, comprising the steps of:
(a) preparing a pollution remedial composition comprising more than 35 volume % but less than 40 volume % of a soluble silicate; from about 0.25 to about 5 volume % of a surfactant; from about 1 to about 5 volume % of a polyol; and the remainder distilled water;
(b) applying the pollution remedial composition to the PCB-containing material in an amount effective to destroy the PCB compounds.
22. The method of claim 21 , wherein the PCB-containing material is a PCB- contaminated surface.
23. The method of claim 21 , wherein the PCB-containing material is a PCB- containing oil.
24. The method of claim 21 , wherein the PCB-containing material is a PCB- containing aqueous solution.
25. The method of claim 21 , wherein the PCB-containing material is a PCB- contaminated soil. |
METHOD FOR TREATING PCB-CONTAINING MATERIALS
FIELD OF THE INVENTION
[0001] This invention pertains to methods for treating PCB-containing oils and PCB- contaminated surfaces, soils, and other materials.
BACKGROUND OF THE INVENTION
[0002] Polychlorinated biphenyls ("PCBs") are known to be highly hazardous materials, and PCB-containing wastes pose a disposal problem. For example, PCB-containing oils, also known generally as transformer oils, must be treated for disposal, by encapsulating or preferably by destroying the PCB compounds. As an undesirable alternative, in some countries PCB-containing oils are stored at special waste sites, or left undisturbed.
[0003] U.S. Patent No. 6,436,884 to Spence, herein incorporated by reference, discloses a desirable pollution remedial composition that can be used to destroy PCB compounds. However, use of compositions such as those of Spence occasionally clog make-up and equipment when formulated or used at ambient temperatures, hi addition, application of the compositions to certain coated and uncoated surfaces contaminated to a level well below the surface may not penetrate the surfaces or coatings on the surfaces to an adequate depth for total destruction of the PCBs.
[0004] Aqueous-based pollution remedial compositions are generally not heated due to the increased production costs. It has now been unexpectedly found that heating of an aqueous- based composition actually lowers production costs, since heating substantially facilitates formation of the composition, hi addition, if the aqueous-based composition is produced on- site, clogging of equipment can be virtually eliminated when heating of the composition is employed.
[0005] Often, difficult to treat vertical surfaces such as walls, or overhead surfaces such as ceilings and rafters have become contaminated with PCBs. For example, sea vessel walls and hulls may be coated with PCB-containing paints, or rafters may be contaminated with
PCB dust created by lighting ballasts or insulation materials. Treatment of such surfaces presents a particular challenge since aqueous-based pollution remedial compositions tend to drip off the surface immediately after application, often resulting in PCB contact times too short to achieve the desired remediation.
[0006] If a way could be found to improve the efficiency and performance of known aqueous-based compositions used in the eradication of PCBs, this would represent a useful contribution to the art. In addition, if a pollution remedial composition could be developed such that it would adhere to vertical surfaces and overhead generally horizontal surfaces like overhead ceilings, this would also represent a useful contribution to the art.
[0007] Were a method developed that would ensure penetration of the remedial composition to the depth required to destroy otherwise inaccessible PCBs, this would also represent a useful contribution to the art. In addition, were a method developed by which emulsifϊcation with an aqueous pollution remedial composition would enhance destruction of PCBs contained in PCB-containing oils such as transformer oils, this would also represent a useful contribution to the art.
BRIEF SUMMARY OF THE INVENTION
[0008] In one embodiment of the invention, a method for treating a PCB-contaminated surface is provided, comprising the steps of: (a) preparing a pollution remedial composition; and (b) spraying the pollution remedial composition at specified pressures and temperatures onto and below the surface. When the pollution remedial composition is to be applied to vertical surfaces such as walls, or overhead surfaces such as ceilings and rafters it can be foamed in accordance with the invention to adhere to these or other generally vertical or horizontal surfaces. When the surface is concrete, core holes can be drilled into the concrete surface.
[0009] In another embodiment of the invention, a method for treating a PCB-containing oil is provided, comprising the steps of: (a) preparing an aqueous pollution remedial composition; and (b) mixing the aqueous pollution remedial composition with the PCB-
containing oil to form an emulsion whereby the aqueous pollution remedial composition destroys the PCB compounds.
[0010] In another embodiment of the invention, a method for treating a PCB- contaminated soil is provided, comprising the steps of: (a) preparing a pollution remedial composition; (b) heating the PCB-contaminated soil in such a manner to vaporize PCBs and optionally water; (c) condensing the vaporized PCBs (and water); (d) collecting the condensate; and (e) mixing the condensate with an effective amount of the pollution remedial composition to destroy the PCB compounds.
[0011] In yet another embodiment of the invention, it has now also been unexpectedly found that the use of distilled water in making up the pollution remedial composition greatly increases the efficiency of PCB destruction in all applications.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Broadly, the pollution remedial composition of the present invention contains more than 35 volume % but less than 40 volume % of a soluble silicate; from about 0.05 to about 10 volume % of a surfactant; from about 1 to about 5 volume % of a polyol; and the remainder water.
[0013] The soluble silicate is preferably sodium silicate. The surfactant is preferably Tergitol brand surfactant, aNP-9.5 surfactant sold by Union Carbide. The polyol is preferably polyethylene glycol. The composition may include other constituents as necessary for added benefits.
[0014] In order to inhibit clogging of equipment, for example, feed lines, hoses, and pumps, during the preparation of the aqueous pollution remedial composition, it is preferred that the water be heated prior to addition to the composition to a temperature in the range of from about 45 0 F to about 130 °F. A more preferred water temperature range is from about 120 °F to about 130 °F. Heating in this fashion can speed up the formation of the aqueous pollution remedial composition by a factor of two, or more, and also reduces the viscosity of the composition. Alternatively, the aqueous pollution remedial composition can be mixed
up at ambient temperature, and then heated to the indicated temperatures during the makeup process.
[0015] In order to prevent separation of the prepared aqueous pollution remedial composition in the field (or for temporary storage), it is preferred that the composition be maintained at a temperature of at least about 75 0 F and preferably at a temperature in the range of from about 90 to 100 °F. It is desirable, in addition to elevating the temperature of the composition, that it also be subjected to generally continuous agitation.
[0016] It is also preferred that distilled water be used to make up the pollution remedial composition. It has now been unexpectedly found that the use of distilled water in the pollution remedial compositions can reduce levels of PCBs to about 10 μg/ 100 cm when the pollution remedial composition is applied to surfaces and to less than about 10 ppb when the pollution remedial composition is applied to PCBs contained in aqueous solutions. The use of distilled water in the pollution remedial composition can also reduce the levels of PCBs in PCB-containing oils (transformer oils), when the pollution remedial composition is applied by mixing with the PCB-containing oil to form an emulsion.
[0017] The pollution remedial composition can be applied to surfaces containing PCBs, such as painted or other coated surfaces, and to concrete or other porous surfaces. For example, power washer equipment can be used to apply the pollution remedial composition to a surface. In a preferred embodiment, the power washer equipment will maintain the temperature of the aqueous pollution remedial composition at about 120 - 130 °F. Heating has the additional benefit of inhibiting clogging of the spraying equipment by the aqueous pollution remedial composition.
[0018] When applying the pollution remedial composition to porous surfaces such as concrete, power washing is substantially superior to conventional unpressurized application techniques. For example, core samples taken after application by mop and power washer, respectively, then pulverized, and analyzed by the standard EPA method (gas chromatography), show much more efficient removal of PCBs for the power washed sample
over the mop applied sample. In another example, field tests have shown that forcing the reagent onto and into the concrete using this power washing technique allows the pollution remedial composition to destroy contaminant PCBs at least several inches (2-5 inches) below the surface of the concrete.
[0019] When the pollution remedial composition is applied to concrete or other porous surfaces, effective spray pressures should be at least about 1000 psi, and preferably can range from about 1000 psi to about 3500 psi. Spray heads applying the pollution remedial composition at these pressures can be positioned about 12-14 inches from the surface to be treated. In addition, generally multiple passes of the spray head are preferred. For example, spray treatment of a surface with the pollution remedial composition by using a heated power washer can increase the percentage of PCB destruction by 25-50% due to the increase of penetration of the composition into the PCB-contaminated surface.
[0020] Appropriate power washers include MiTM Heated power washer 4000 series, available from MTM Corp. (Des Moines , Iowa), and Hotsy, available from Hotsy Company (Englewood, Colorado).
[0021] In one embodiment of the invention, a concrete surface contaminated with PCBs can be treated with the pollution remedial composition by first drilling a grid of core holes to the depth of the contamination (as measured by analysis). For example, a grid of core holes having a diameter of about 1 inch, spaced at about 10 inches from one another, each core hole drilled to a depth of about 6-8 inches, may be formed. This drilled concrete grid is then treated with a pollution remedial composition by power washing over the entire concrete surface. The result is that the pollution remedial composition will fill and penetrate the concrete both through the uncored surface of the concrete and through the core holes. Various diameter core holes, core hole depth, and core hole spacing can be employed; these grid parameters will be determined by the extent of PCB contamination to be remediated, the physical parameters of the concrete, and the level of PCB contamination.
[0022] When the pollution remedial composition is applied to painted or coated surfaces (or coated substrates), in addition to power washing as described above, the composition can be heated and applied directly, simply by using a mop, for example. If the pollution remedial composition is used to treat a surface covered with a PCB-containing paint, for example, the paint will comminute or dissolve and run off of the treated surface. PCBs residing in the paint will be destroyed by the pollution remedial composition. In a yet more preferred embodiment, the pollution remedial composition could be sprayed on in such a manner that the paint or coating is comminuted or dissolved, in order to accelerate destruction of PCBs in the paint or coating. The resulting treated paint can be collected and properly disposed of, or if appropriate, further treated to remove or stabilize other hazardous components such as lead, as described, for example, in U.S. Patent Nos. 5,536,899, 5,722,928, and 5,846,178, which are herein incorporated by reference. Lead remediation or stabilization as in the foregoing patents can be carried out ex situ or in situ.
[0023] In another embodiment, the pollution remedial composition can be applied to PCB-contaminated soils by spraying onto the soil or by injecting directly into the soil, thus effecting a reduction in PCB levels of at least about 85-90%.
[0024] In another embodiment, the pollution remedial composition of the present invention can be used to treat heated air-extracted contaminants from soil and other sources. A method of hot air extraction of contaminants, such as PCBs, is described in U.S. Patent 5,213,445, which is herein incorporated by reference. As explained there, the contaminated soil or other contaminated source is heated to vaporize the PCBs (along with moisture and possibly other materials), the vapor is condensed, and the condensate (preferably aqueous) is collected. This collected condensate can then be treated by mixing with an appropriate amount of the pollution remedial composition in order to achieve a yet greater reduction in PCB levels, up to about 100% destruction of PCBs.
[0025] In another embodiment of the invention, the pollution remedial composition can include a foaming agent. Useful foaming agents include anionic surfactants, such as, for example, polyether sulfonates, and the like. A foamed composition allows for a longer
contact period with the surface being treated, and consequently more efficient destruction of the PCBs. The properties of the foamed composition allow for better adherence to a given surface. The foamed pollution remedial composition can also be used to treat otherwise difficult to treat generally vertical surfaces such as walls, as well as overhead generally horizontal surfaces like ceilings and rafters that have become contaminated with PCBs. For example, sea vessel walls and hulls may be coated with PCB-containing paints, or rafters may be contaminated with PCB dust created by lighting ballasts or insulation materials. In order to address these types of remediation applications, a pollution remedial composition including a foaming agent can be used in order to allow for a longer contact period with the difficult to treat surface, and consequently more efficient destruction of potentially harmful PCBs.
[0026] In order to use the pollution remedial composition including a foaming agent, the foaming agent may be added to the pollution remedial composition before application to a surface, for example, a generally vertical surface so that the foam is generated upon application by spraying. For example, a foam nozzle would be used to distribute the foamed pollution remedial composition substantially evenly over broad surface areas.
[0027] The pollution remedial composition can be used to treat transformer oils containing PCBs. In this embodiment of the invention, the aqueous-based pollution remedial composition is combined with a transformer oil and mixed to form an emulsion. These prepared emulsions can be substantially stable, which allows intimate contact of the aqueous-based pollution remedial composition with the PCB contaminants. The aqueous/oil volume ratio can be about 1:1. Alternatively, the amount of the aqueous-based composition can be increased, and aqueous/oil volume ratios can range from about 1.1 : 1 to 2:1, or from about 2:1 to 5:1. Various parameters, such as mixing, agitation, and extraction, for example, can be changed in order to effect maximum destruction of PCBs in the transformer oil. Water-soluble salts can be added to aid in breaking the emulsions and separating the phases after treatment with the aqueous-based pollution remedial composition. The separated treated oil and water phases then can be either properly disposed of, or recycled. Alternatively, after treatment of the transformer oil with the
aqueous-based pollution remedial composition to form an emulsion, where PCBs have been destroyed or reduced to a non-hazardous level, the emulsion itself can be safely discarded.
[0028] A soluble silicate, such as an alkali-metal silicate solution, must be used in the pollution remedial composition of the present invention. One preferred soluble silicate is sodium silicate. Useful commercial sodium silicates include sodium silicate available from Brenntag Chemical Co., Reading, Pennsylvania. In a preferred embodiment, soluble sodium silicate in this invention is present at a level more than 35 volume % but less than 40 volume %, based on the total volume of the final pollution remedial composition.
[0029] Surfactants must be used in the pollution remedial composition of the present invention. In one embodiment of the present invention, the preferred surfactants are the nonionic surfactants. A useful nonionic surfactant is Tergitol, aNP-9.5 surfactant sold by Union Carbide, or available from Dow Chemical Co., Midland, Michigan.
[0030] The surfactant in this invention is present at a level from about 0.05 to about 10%, based on the total volume of the final pollution remedial composition. Preferably, the surfactant should be present at a level from about 0.25 to about 2 volume %.
[0031] The next ingredient used for the present invention is a polyol. Known polyols include different glycols, glycerins, sugars, and polyethylene glycols. These polyols are compatible and miscible with alkali-metal silicate solutions. One preferred polyol for this invention is polyethylene glycol. Propylene glycol can also be used for application to environmentally sensitive sites.
[0032] Polyol in this invention is present at a level from about 1 to about 5%, based on the total volume of the final pollution remedial composition. Preferably, polyol should be present at a level from about 2 to about 5 volume %.
[0033] Water forms the remainder of the pollution remedial composition of the present invention. Water is present in an amount of about 50 volume % or greater, based on the total volume of the final pollution remedial composition. Preferably, it should be present in
an amount greater than 50 volume %. Distilled water is preferred in the pollution remedial compositions.
[0034] In addition, foaming agents can be used in embodiments of the present invention. A preferred foaming agent is Triton X-200 high foam surfactant, available from Dow Chemical Co., Midland, Michigan. When foaming agents are added to the pollution remedial composition, they can be present in an amount from about 0.25 to about 5 volume %, based on the total volume of the final pollution remedial composition.
[0035] Table 1 shows a preferred pollution remedial composition in accordance with the invention:
TABLE 1
[0036] Another preferred pollution remedial composition includes 38.0 volume % soluble silicate; 0.5 volume % surfactant; 4 volume % polyol; and the remainder water.
[0037] The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.
COMPARATIVE EXAMPLE 1 [0038] Analysis of Transformer Oil
[0039] A sample of transformer oil (40 ml) was extracted using USEPA Method 3580 A. The resulting extract was analyzed for PCBs by gas chromatography using USEPA SW-846 Method 8082. The oil was found to contain 3.42 mg/kg of the PCB mixture Aroclor 1260.
COMPARATIVE EXAMPLE 2 [0040] Analysis of Steel Plate Surface having Transformer Oil Spilled on Surface
[0041] A sample of the transformer oil (473 ml) of Comparative Example 1 was poured onto a steel plate. Then, a 100 cm 2 area was wiped gauze saturated with hexane, and the wipe sample was extracted using USEPA Method 3550A, using hexane sonication extraction according to EPA protocol as described in EPA 560/5-85-026. The resulting extract was analyzed for PCBs by gas chromatography using USEPA Method 8082. The oil was found to contain 704 μg/ 100 cm 2 of the PCB mixture Aroclor 1260.
EXAMPLE 1 [0042] Preparation of Reagent A
[0043] A pollution remedial composition (referred to below as Reagent A) is made by adding with agitation, about 0.5 volume % Tergitol surfactant, based on the total volume of the final pollution remedial composition, to distilled water heated to 120-130 °F and present in an amount of about 57.5 volume % to obtain a first substantially homogeneous resultant mixture. Then, with agitation, about 4.0 volume % of polyethylene glycol is added to the first resultant mixture to obtain a second substantially homogeneous resultant mixture. Finally, with agitation, about 38.0 volume % of sodium silicate is added to give a substantially homogeneous final pollution remedial composition. Agitation and heating of the composition at 120-130 °F are maintained until use.
EXAMPLE 2 [0044] Treatment of Transformer Oil by Emulsification with Reagent A
[0045] Equal volumes of Transformer Oil (Comparative Example 1) and Reagent A were combined and mixed in an electric mixer to form a thick white emulsion. This emulsion did not break, except for a small amount of clear aqueous phase that separated out. Centrifuging the emulsified mixture was not effective in breaking the emulsion. The emulsified mixture was next extracted using three methods.
[0046] 1. USEPA Method 3580A. This extract was found to contain 0.39 mg/kg of the PCB mixture Aroclor 1260.
[0047] 2. Modified USEPA Method 3580A. After dilution, the extract was place in an ultrasonic bath for 15 min. The extract was found to contain 0.958 mg/kg of the PCB mixture Aroclor 1260.
[0048] 3. USEPA Method 3550A. This extract was found to contain 1.47 mg/kg of the PCB mixture Aroclor 1260.
[0049] As shown by extraction method 3 (the most aggressive extraction), the PCB concentration in the transformer oil was reduced by over 50% using Reagent A. PCB reduction may be still further improved by adjusting the percentage of surfactant in the pollution remedial composition, or by further or more efficient agitation. Alternatively, PCB reduction may be further improved by increasing the amount of Reagent A used in the treatment of the transformer oil, that is, by increasing the aqueous/oil volume ratio.
EXAMPLE 3 [0050] Treatment of Steel Plate having Spilled Transformer Oil with Reagent A
[0051] A sample of the transformer oil (473 ml) of Comparative Example 1 was poured onto a steel plate. Next, the same area of the steel plate was treated with an equal volume of Reagent A (473 ml). After processing as in Comparative Example 2, the resulting extract
was analyzed for PCBs by gas chromatography using USEPA Method 8082. The oil was found to contain <50 μg/ 100 cm 2 of the PCB mixture Aroclor 1260.
[0052] As shown in this example, treatment of the contaminated steel surface with Reagent A resulted in the destruction of PCBs to below detectable levels. Comparison with Comparative Example 2 demonstrates the level of PCB destruction achieved.
EXAMPLE 4
[0053] Increase in Efficiency of Reagent A Prepared Using Distilled Water
[0054] If a pollution remedial composition were prepared as in Example 1 , but distilled water were replaced with water taken from a municipal water supply in Pittsburgh, Pennsylvania, more of the pollution remedial composition would be required to effect destruction of PCBs in a given volume of a transformer oil sample in comparison to Reagent A (Example 1) used to treat the same volume of transformer oil. That is, due to higher efficiency of PCB destruction using Reagent A, a smaller total volume of pollution remedial composition would be required to effect the same amount of PCB remediation.
EXAMPLE 5
[0055] Reagent A or Foamed Reagent A Used for Treatment of a Ceiling coated with PCB-containing paint.
[0056] If a ceiling coated with a PCB-containing paint were treated using Reagent A by spraying with a heated pollution remedial composition in accordance with the invention, a significant level of PCB destruction would be achieved.
[0057] However, if lower PCB levels are required, a foaming agent (high foam surfactant) may be added in an amount of about 0.25-5 volume % based on the total volume of the pollution remedial composition, and the foamed Reagent A composition sprayed
against the painted surface. It will be found that a foam is formed that will adhere to the ceiling and achieve substantially improved PCB destruction.
EXAMPLE 6
[0058] Elimination of Equipment Clogging Using Heated Reagent A
[0059] On many occasions the feed hose from the Reagent A supply tank to the contaminated area clogs, and in some cases actually needs to be replaced because of buildup. Non-heated pressure washers also clog when constant Reagent A applications and flows are delayed. However, when Reagent A is maintained at a temperature of at least 120 - 130 °F, it is found that none of the above clogging problems remain.
EXAMPLE 7
[0060] Treatment of PCB-Containing Concrete with Reagent A
[0061] If a concrete surface were impregnated with PCBs from leaking transformers, the contaminated concrete could be treated in accordance with this invention. In this case, heated Reagent A could be applied by spraying at a pressure of 1000 psi at a rate of 2-2.5 gal./min./ft over 1 min., with at least 2-3 spraying passes.
[0062] If concrete test cores were taken prior to and following the treatment, it would be found that at least a 90% reduction in PCB levels (up to a depth of 3 inches) would be obtained.
[0063] In the case of particularly severe PCB contamination of the concrete surface, if core holes were bored having a 1 in. diameter and a 6 inch depth, the core holes spaced in a squared grid at an average spacing of 6-10 in. from one another, and the above pollution remedial solution (Reagent A) and spray process were employed, a yet greater reduction in PCB level would be achieved.
[0064] When used in this disclosure, the terms "destroys," "destroying," and "destruction," when used in connection with PCBs, means reacts, reacting, reacted, or reaction to produce generally benign chemical by-products.
[0065] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
[0066] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
[0067] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention.
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