SYSTEMS AND METHODS FOR TREATMENT OF CONTAMINATED FOAM STREAMS USING REACTIVE METAL OXIDES

Abstract

A method and system for the destruction of PFAS compounds using reactive metal oxides is disclosed herein. The method includes introducing a metal oxide into a vessel, where the vessel is heated to a temperature in a range of approximately 300 C. to approximately 700 C. The method also includes introducing a contaminated stream to the vessel, where the contaminated stream includes one or more PFAS compound. The method also includes reacting the contaminated stream with the metal oxide. The method also includes, resultant to the reacting, producing a solid non-toxic product.

Claims

1. A method for the destruction of PFAS compounds, the method comprising: (a) introducing a metal oxide into a vessel, wherein the vessel is heated to a temperature in a range of approximately 300 C. to approximately 700 C.; (b) introducing a contaminated stream to the vessel, wherein the contaminated stream comprises one or more PFAS compound; (c) reacting the contaminated stream with the metal oxide or hydrohide; and (d) resultant to the reacting, producing a solid non-toxic product.

2. The method of claim 1, wherein the metal oxide comprises CaO, wherein the CaO is produced by the thermal decomposition of Ca(OH)2 under an air atmosphere.

3. The method of claim 1, wherein the metal oxide comprises CaO, wherein the CaO is produced by the thermal decomposition of Ca(OH)2 under an inert gas atmosphere.

4. The method of claim 3, wherein the inert gas atmosphere comprises nitrogen, argon, or a combination thereof.

5. The method of claim 1, wherein the metal oxide comprises CaO, wherein the CaO is produced by the thermal decomposition of Ca(OH)2 under vacuum conditions.

6. The method of claim 1, wherein the metal oxide comprises CaO, wherein the CaO is produced by the thermal decomposition of Ca(OH)2 over a period of at least one minute.

7. The method of claim 1, wherein the metal oxide comprises CaO, wherein the CaO is produced by the thermal decomposition of Ca(OH)2 at moderate temperatures within the range of approximately 400 C. to 500 C. over a period of one minute.

8. The method of claim 1, wherein the metal oxide comprises MgO, wherein the MgO is used as the metal oxide under an air atmosphere.

9. The method of claim 1, wherein MgO is used as the metal oxide under an inert gas atmosphere.

10. The method of claim 9, wherein the inert gas atmosphere comprises nitrogen, argon, or a combination thereof.

11. The method of claim 1, wherein MgO is used as the metal oxide under vacuum conditions.

12. The method of claim 1, wherein MgO is used as the metal oxide produced by thermal decomposition over a period of at least one minute.

13. The method of claim 1, wherein MgO is used as the metal oxide at moderate temperatures within the range of approximately 400 C. to 500 C. over a period of one minute.

14. The method of claim 1, wherein the vessel comprises a packed bed filled with CaO, MgO, Ca(OH)2, Mg(OH)2, or combinations thereof.

15. The method of claim 1, wherein the vessel comprises a fluidized bed filled with CaO, MgO, Ca(OH)2, Mg(OH)2, or combinations thereof.

16. The method of claim 1, wherein the vessel comprises a spouted bed filled with CaO, MgO, Ca(OH)2, Mg(OH)2, or combinations thereof.

17. The method of claim 1, wherein the vessel comprises a kiln with CaO, MgO, Ca(OH)2,Mg(OH)2, or combinations thereof.

18. The method of claim 1, wherein the non-toxic product comprises a non-toxic calcium fluoride (CaF2).

19. The method of claim 1, wherein the non-toxic product comprises a non-toxic magnesium fluoride (MgF2).

20. The method of claim 1, wherein the contaminated stream comprises PFAS-contaminated solid waste.

21. The method of claim 1, wherein the contaminated stream comprises PFAS-contaminated gaseous or vapor waster.

22. The method of claim 1 further comprising, prior to introducing the metal oxide and the contaminated stream into the vessel, pre-mixing the metal oxide with the contaminated stream.

23. The method of claim 1, wherein the metal oxide comprises commercially available CaO.

24. The method of claim 1, wherein the metal oxide comprises commercially available MgO.

25. A system for the destruction of PFAS compounds, the system comprising: (a) a vessel comprising (i) an inlet to receive a contaminated stream, wherein the contaminated stream comprises a PFAS compound, (ii) an interior to house the contaminated stream, and (iii) one or more outlets configured to allow solid product removal and steam removal from the vessel; (b) a metal oxide, wherein (i) the metal oxide is housed within the interior of the vessel, (ii) the metal oxide has enhanced chemical reactivity with the PFAS compound in the contaminated stream, and (iii) the metal oxide reacts with the PFAS compound at temperatures ranging from approximately 300 C. to 700 C. to produce a solid non-toxic product; and (c) a heat source configured to heat the vessel to a reaction temperature in a range of approximately 300 C. to 700 C.

26. The system of claim 25, wherein the metal oxide comprises Ca(OH)2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH)2 under an air atmosphere.

27. The system of claim 25, wherein the metal oxide comprises Ca(OH)2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH)2 under an inert gas atmosphere.

28. The system of claim 27, wherein the inert gas atmosphere comprises nitrogen, argon, or a combination thereof.

29. The system of claim 25, wherein the metal oxide comprises Ca(OH)2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH)2 under vacuum conditions.

30. The system of claim 25, wherein the metal oxide comprises Ca(OH)2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH)2 over a period of at least one minute.

31. The system of claim 25, wherein the metal oxide comprises Ca(OH)2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH)2 at moderate temperatures within a range of approximately 400 C. to 500 C. over a period of one minute.

32. The system of claim 25, wherein the metal oxide comprises MgO, and the heat source is configured to produce MgO as the metal oxide under an air atmosphere.

33. The system of claim 25, wherein the metal oxide comprises MgO, and the heat source is configured to produce MgO under an inert gas atmosphere.

34. The system of claim 33, wherein the inert gas atmosphere comprises nitrogen, argon, or a combination thereof.

35. The system of claim 25, wherein the metal oxide comprises MgO, and the heat source is configured to produce MgO under vacuum conditions.

36. The system of claim 25, wherein the metal oxide comprises MgO, and the heat source is configured to produce MgO over a period of at least one minute.

37. The system of claim 25, wherein the metal oxide comprises MgO, and the heat source is configured to produce MgO at moderate temperatures within a range of approximately 400 C. to 500 C. over a period of one minute.

38. The system of claim 25, wherein the vessel comprises a packed bed filled with CaO, MgO, Ca(OH)2, Mg(OH)2, or combinations thereof.

39. The system of claim 25, wherein the vessel comprises a fluidized bed filled with CaO, MgO, Ca(OH)2, Mg(OH)2, or combinations thereof.

40. The system of claim 25, wherein the vessel comprises a spouted bed filled with CaO, MgO, Ca(OH)2, Mg(OH)2, or combinations thereof.

41. The system of claim 25, wherein the vessel comprises a kiln with CaO, MgO, Ca(OH)2,Mg(OH)2, or combinations thereof.

42. The system of claim 25, wherein the non-toxic product comprises a non-toxic calcium fluoride (CaF2).

43. The system of claim 25, wherein the non-toxic product comprises a non-toxic magnesium fluoride (MgF2).

44. The system of claim 25, wherein the metal oxide comprises commercially available CaO.

45. The system of claim 25, wherein the metal oxide comprises commercially available MgO.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other advantages of the present invention will be apparent from the following detailed description of the invention in conjunction with embodiments as illustrated in the accompanying drawings, in which:

[0030] FIG. 1 depicts a continuous foam fractionation system for use with water contaminated with PFAS, in accordance with certain embodiments of the present disclosure.

[0031] FIG. 2 depicts a process for removing and disposing of concentrated PFAS using a continuous foam fractionation system for use with water contaminated with PFAS, in accordance with certain embodiments of the present disclosure.

[0032] FIG. 3 depicts a supercritical water oxidation method for use in a process for removing and disposing of concentrated PFAS using a continuous foam fractionation system for use with water contaminated with PFAS, in accordance with certain embodiments of the present disclosure.

[0033] FIG. 4 depicts a block diagram of a method for using a continuous foam fractionation system to treat water contaminated with PFAS, in accordance with certain embodiments of the present disclosure.

[0034] FIG. 5 depicts a diagram of a modular system that allows for flexibility in flow and concentration based on capabilities and needs of a system, in accordance with certain embodiments of the present disclosure.

[0035] FIG. 6 depicts a diagram of a system that allows for flow routing using a plurality of inlet ports, in accordance with certain embodiments of the present disclosure.

[0036] FIG. 7 depicts a diagram demonstrating the ability to increase concentration in system that allows for the modular components in a system flexible foam fractionation to be removed from a housing, in accordance with certain embodiments of the present disclosure.

[0037] FIG. 8 depicts a foam fractionation system with ports for adding additional surfactant, in accordance with certain embodiments of the present disclosure.

[0038] FIG. 9 depicts an angled foam fractionation column, in accordance with certain embodiments of the present disclosure.

[0039] FIG. 10 depicts a schematic continuous process for treating PFAS/PFOA contaminated foam streams with reactive metal oxides, in accordance with embodiments of the present disclosure.

[0040] FIG. 11 depicts a schematic of the first step of a two-step batch process for treating PFAS/PFOA contaminated foam streams with reactive metal oxides, showing the capture of PFAS/PFOA contaminated foam in accordance with embodiments of the present disclosure.

[0041] FIG. 12 depicts a schematic of the second step of a two-step batch process for treating PFAS/PFOA contaminated foam streams with reactive metal oxides, showing the actual destruction of the PFAS/PFOA compounds in accordance with embodiments of the present disclosure.

[0042] FIG. 13 depicts an apparatus PFAS/PFOA mineralization, in accordance with certain embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0043] The present disclosure relates to system and methods for using foam fractionation to remove a PFAS contaminant from a water source. In accordance with one or more embodiments, the systems and methods disclosed herein relate to the separation, concentration, and destruction of PFAS from a source of water that is contaminated with PFAS.

[0044] As discussed above, the man-made PFAS chemical compounds are highly stable because of the mentioned carbon-fluorine bonds, which are longstanding and do not readily decompose in the environment. Additionally, PFASespecially PFAS from products in which it was used as a repellant and protective coatinghas cumulated in various water supplies. Even with largescale efforts to phase out the use of PFAS compounds, elevated levels of the forever chemicals remain present throughout the environment. PFAS may be found in areas near prevalent uses of prior PFAS products (such as near fire training facilities) and in locations where PFAS has migrated through water and air.

[0045] In some non-limiting embodiments, prevalent PFAS, such as PFOS and PFOA, may be removed from water using the methods and systems disclosed herein.

[0046] Additionally, based on the EPA's revised guidelines published in May 2016 and recent regulation efforts, water distribution and filtering facilities are now aware of the limits of a combined lifetime exposure of 70 parts per trillion (ppt) for PFOS and PFOA. In some cases, the systems described herein can maintain a concentration of PFAS in treated water to be below the regulated and advised levels.

[0047] In certain embodiments, the overall process, can be characterized by taking a PFAS-concentration of at least 100 ppm PFAS by weight (in some embodiments at least 500 ppm or at least 1000 ppm PFAS) to 1 ppm or less, or 0.1 ppm or less, or 0.01 ppm or less. Alternatively, by taking a PFOA-concentration of at least 100 ppm PFOA by weight (in some embodiments at least 500 ppm or at least 1000 ppm PFOA) to 1 ppm or less, or 0.1 ppm or less, or 0.01 ppm or less, or 1.0 ppb or less, or 0.1 ppb or less, or 0.01 ppb or less PFOA; in some embodiments in the range of 1 ppm to 5 ppt (part per trillion) PFOA. Alternatively, by taking a PFOS-concentration of at least 100 ppm PFOS by weight (in some embodiments at least 500 ppm or at least 1000 ppm PFOS) to 1 ppm or less, or 0.1 ppm or less, or 0.01 ppm or less, or 1.0 ppb or less, or 0.1 ppb or less, or 0.01 ppb or less PFOS; in some embodiments in the range of 1 ppm to 5 ppt (part per trillion) PFOS. The process can also be characterized by the same levels of destruction beginning with a PFAS concentration of less than 100 ppm. In some embodiments, PFAS-contaminated water comprising at least 1000 ppt of at least one (or at least 3 or at least 4 or at least 5 or at least 6) compound selected from the group consisting of PFHxA (perfluorohexanoic acid), PFHpA (perfluoroheptanoic acid), PFOA, PFBS (perfluorobutane sulfonate), PFHxS (perfluorohexane sulfonate), PFHpS (perfluoroheptane sulfonate), and PFOS and combinations thereof, treated by the process is (are) reduced by at least 2 (or at least 3 or at least 4 or at least 5) orders of magnitude. In some embodiments, PFAS-contaminated water comprising at least 100 ppt of at least one (or at least 3 or at least 4 or at least 5 or at least 6) compound selected from the group consisting of PFBA (perfluorobutanoic acid), PFPeA (perfluoropentanoic acid), PFHxA, PFHpA, PFOA, 6:2 FTS (6:2 fluorotelomer sulfonate), and 8:2 FTS (8:2 fluorotelomer sulfonate) and combinations thereof, treated by the process is (are) reduced by at least 2 (or at least 3 or at least 4 or at least 5) orders of magnitude and/or reduced to 5 ppt (or 1 ppt) or less.

[0048] FIG. 1 depicts a continuous foam fractionation system for use with water contaminated with PFAS, in accordance with certain embodiments of the present disclosure.

[0049] In some embodiments, separation of PFAS from a source of contaminated water may be achieved using foam fractionation. In such an embodiment, and in accordance with the system shown in FIG. 1, hydrophobic moleculesincluding the PFAS molecules contaminating the watercan be removed and extracted as a foam. Specifically, in such an embodiment, air can be introduced to a container to produce gas bubbles. In some embodiments, the container is a column, a tank, a vessel, a tube, or combinations thereof. In embodiments of the present disclosure, multiples containers are utilized in order to allow for continuous foam fractionation. In the embodiment of FIG. 1, the configuration allows for air to rise through of contaminated water. In such an embodiment, as air rises through the contaminated water bubbles may be formed. Such bubbles, in this embodiment and as depicted in FIG. 1, allow for the removal of hydrophobic molecules. In such an embodiment, the bubbles will have an air-water interface with a large surface area. The groups on PFAS molecules adsorb to the bubbles of the foam and form a surface layer enriched in PFAS that can subsequently be removed.

[0050] In some embodiments, the gas introduced to the system of FIG. 1 may be compressed air or nitrogen. In other embodiments, the gas introduced to the system can be an oxidizing gas, such as ozone.

[0051] In some embodiments, the gas is introduced from the base of the container that houses the contaminated water. Further, in some embodiments, the pressure of the container can operate to facilitate the movement of the gas bubbles through the contaminated water and help to form a foam layer.

[0052] FIG. 1 shows that the initial inlet in the fractionation column can operate as a point of entrance for a feed stream, where the feed stream contains both water and the PFAS contaminant. As further shown in FIG. 1, the introduction of air from the base of the fractionation column can rise to cause bubbles to propel through the feed in the container and ultimately cause the collection of foam concentrated with the PFAS contaminant at the top of the system of FIG. 1.

[0053] FIG. 1 also shown that the feed outlet in one fractionation column can be operatively connected to allow the feed stream to immediately feed into the next fractionation column. In some embodiments, the feed outlet is placed at an upper region of each fractionation column.

[0054] Further, as depicted in FIG. 1, in some embodiments, at the top of each fractionation column, there can exist an outlet that allows the feed stream to flow from one foam fractionation column to the next. In some embodiments, the system can include a series of fractionation columns, which can be used to increasingly purify the water by the continuous foam fractionation. In such an embodiment, the PFAS in feed stream will be repeatedly gathered as the feed stream passes through each column. In such an example, the feed stream entering the system will have an initial concentration of PFAS. Following, after the feed stream passes through the first foam fractionation column, the feed stream, which now may be referred to as the purified stream, will have a lower concentration of PFAS. In such an embodiment, this is because many of the PFAS molecules have been removed and isolated in the foam that rests atop the purified stream. Thus, as mentioned, in such embodiments, the concentration of PFAS in the purified stream exiting each column will be lower than that of the feed stream that initially entered the column.

[0055] Further, in some embodiments, the system can discharge the feed stream, which can then be referred to as the cleaned stream, once it has a sufficient amount of the PFAS removed. For example, in some embodiments, the cleaned stream can be removed from the system when there is less than 70 parts per trillion (i.e., below the regulatory recommended amount from the EPA's guidance) of PFAS remaining in the cleaned stream. In certain embodiments, the final amount of PFAS left in the cleaned stream may be 1 ppm or less, or 0.1 ppm or less, 0.01 ppm or less, 0.001 ppm (1 ppb) or less, 0.0001 ppm (0.1 ppb) or less, 0.00001 ppm (0.01 ppb) or less, or 0.000001 ppm (0.001 ppb or 1 ppt) or less.

[0056] Prior PFAS/PFOA treatment processes, produced gaseous exhaust streams contaminated with residual PFAS/PFOA vapors, toxic gases or vapors, or their mixtures. Release of these streams into environment may be problematic without further treatment. The common method to treat such exhaust streams is to send them through a bed of activated carbon or some other treatment media that capture PFAS/PFOA and other pollutants via adsorption or ion exchange. Such treatment methods are non-destructive, therefore, only convert the gaseous waste stream into solid waste stream containing the same pollutants.

[0057] The present disclosure utilizes chemically reactive media to capture pollutants and irreversibly destroy such contaminates. The present disclosure provides a method and system for PFAS/PFOA destruction using calcium and magnesium oxides and hydroxides to produce reactive forms of CaO and MgO and, subsequently, use these oxides to destroy PFAS/PFOA compounds.

[0058] As is also shown in FIG. 1, the system can also include a final outlet that can discharge the feed stream. In some embodiments, the cleaned stream, which will include primarily water or aqueous solution, once discharged from the final outlet of the system may be released back into the environment. In such an embodiment, the cleaned stream can contain minimal amounts of PFAS, such that the concentration of PFAS in the cleaned stream does not pose a risk to humans, animal, or wildlife that the water source may reach once back in the environment.

[0059] In the embodiment depicted in FIG. 1, the process can be a fully continuous, multistage process. In such an embodiment, the process can have a high throughput. Further, such an embodiment presents the benefit of having an unlimited scalability, where the process can be used on a small scale for testing small portions of potentially contaminated water, or on a large scale where vast amounts of contaminated water may be run through the continuously run system. Because of the continuous foam fractionation, the system depicted in FIG. 1 may be easily operated without the need for excessive interaction and invention from operators of the system.

[0060] In some embodiments, the system as depicted in FIG. 1 may include a feed stream that has an effective amount of a surfactant added therein. In such an embodiment, the surfactant can interact with the PFAS contaminant to create a complexing agent. Accordingly, such a system may be utilized to effective remove light PFAS from a contaminated water source. For example, light PFAS, referring to PFAS with C-4 or less, which may not rise in a standard foam fractionation process may be removed in an enhanced manner through the use of such surfactant. Specifically, in such an embodiment, the light PFAS foam layer comprises the complexing agent. Surfactants may be introduced at different locations. For example, in some embodiments, the surfactants may be introduced prior to the feed stream entering the column. In other embodiments, the surfactants may be introduced to a purified stream in a series of active columns. Moreover, in some embodiments, the system may include multiple surfactant addition points, where the surfactants are added to the feed stream, the purified stream, or combinations thereof.

[0061] In some embodiments, where the later columns in the system generate an insufficient amount of foam due to depletion of surfactant from the feed stream in the earlier columns, the system and process can further include adding additional surfactant into various columns throughout the system, which ensures that sufficient surfactant is present in all columns of the system. In such an embodiment, there can be a significant benefit of allowing for the addition of more columns to the system. Accordingly, in some embodiment, the foam fractionation system include ports for surfactant addition throughout the foam fractionation columns to achieve the target separation.

[0062] As shown in FIG. 8, which depicts a foam fractionation system with ports for adding additional surfactant, in accordance with certain embodiments of the present disclosure, the ports may be installed into a certain number of columns. For example, and as shown in FIG. 8, the ports for adding surfactant may be added into every other column. The addition of surfactants at the ports can allow for the volume of foam produced can be optimized in each stage. In some embodiments, different surfactant amounts and/or types may be injected at different points.

[0063] In some embodiments of the system, once a contaminated water source is identified, the contaminated water source is then fed to the system in a feed stream, as is shown in FIG. 1 and discussed above. Further, in this embodiment, the feed stream once in a foam fractionation column may be super-saturated with air. In such an example, the air can be pumped, injected, or flowed through the contaminated water in the foam fractionation column. Because the feed stream is super saturated, the air bubbles rise through the water, while proteins, amphipathic species, and contaminants adsorb to the surface of the air bubbles. In such an embodiment, the air bubbles can then collects as a foam on top of the feed stream in the foam fractionation column.

[0064] In some embodiments, the system of FIG. 1 may be utilized with pH and/or ionic strength adjustments. In such an embodiment, particular additives may be added to the feed stream entering the system in order to control the system at a particular operating pH. In certain embodiments, being used either in conjunction with the pH control additives or independently, particular additives may be added to the feed stream entering the system in order to control the system at a particular operating ionic strength. In such an example, the system of FIG. 1 may be used not only with ground water from PFAS contaminated locations, but also with highly contaminated streams containing large amounts of inorganics in addition to PFAS.

[0065] FIG. 2 depicts a process for removing and disposing of concentrated PFAS using a continuous foam fractionation system for use with water contaminated with PFAS, in accordance with certain embodiments of the present disclosure. In such embodiments as shown in FIG. 2 the foam collected from the initial system as shown in FIG. 1 may be further run through continuous fractionation systems. For example, the stored and collected PFAS contaminates collected in the foam layer of one process may then be run through the inlet of a further foam fractionation system having similar characteristics, structure, and conditions as those described in accordance with FIG. 1. In some embodiments, the concentrated PFAS entering a foam fractionation continuous, multistage system may enter the system and then a highly concentrated PFAS may be collected in the foam layer of that system. In some embodiments, once the PFAS is highly concentrated, the PFAS may then be sent to a device for permanent destruction. For example, the PFAS may be sent to a supercritical water oxidation method.

[0066] In some embodiments, the foam fractionation system of FIG. 2 may include different arrangements of foam fractionation columns that are tailored to specific requirements. In certain embodiments, the specific requirements are pre-determined.

[0067] In some embodiments, the specific requirements include, but are not limited to, the amount of wastewater to be processed, the flow at which the processing needs to be carried out, and a degree of PFAS concentration required.

[0068] There can be a variety of possible arrangements for the process, one embodiment of such process shown in FIG. 2. As shown in FIG. 2, eight foam fractionation columns can be used to treat the incoming water contaminated with PFAS and to convert it to clean water. As also shown in FIG. 2, the foam produced by these columns can be further treated in two groups of foam fractionation columns, for example with each consisting of four columns. In embodiments where there are large amounts of wastewater to be treated, the process may use additional columns connected in parallel.

[0069] FIG. 3 depicts a supercritical water oxidation method for use in a process for removing and disposing of concentrated PFAS using a continuous foam fractionation system for use with water contaminated with PFAS, in accordance with certain embodiments of the present disclosure. The disclosure and teachings of U.S. Pat. No. 11,401,180 B2, entitled Destruction of PFAS via an oxidation process and apparatus suitable for transportation to contaminated sites are incorporated by reference in their entirety.

[0070] A preferred system 300 is illustrated in FIG. 3. In the embodiment of FIG. 3, PFAS-contaminants 302, as can be extracted by the system of FIGS. 1 and 2, enters mixing tee 304. In certain preferred embodiments, the PFAS-contaminants enters the tee at ambient conditions (room temperature) or relatively low temperature so that the inlet line is not corroded. In the mixing tee, the PFAS-contaminants 302 are mixed with hot, clean water 306, which may be, for example, 650 C. The combined stream can be at a combined temperature.

[0071] The oxidant 324 can be in either stream 302 or 306. In preferred embodiments, the oxidant 324 is in stream 306 to prevent premature reaction. Combined stream 308 passes into Supercritical Water Oxidation (SCWO) reactor 310. In some embodiments, the SCWO reactor 310 is a vertical tube, in respect to gravity, surrounded by insulation and heating means for start-up. Temperature in the SCWO reactor 310 in certain embodiments is in the range of 500 to 700 C.

[0072] The effluent 312 can passes into a salt separator 314 where salt can be removed manually or through exhaust system 316. In such an embodiment, the system is left as brine 318. Salt can be a mixture of sodium chloride, sodium fluoride, sodium sulfate, sodium nitrate or corresponding salts of other alkali or alkaline earth elements.

[0073] Fluid 320, in certain embodiments, leaves the separator and is routed through a heat exchanger 322, in the direction indicated such that temperature of fluid 320 is highest where the clean water 306 leaves the heat exchanger.

[0074] In some embodiments, after passing the heat exchanger, the clean water 306 may optionally be passed through heater 326 to heat the water to 600 C. or higher. After passing through the heat exchanger, effluent 328 can leave the system and optionally be neutralized at any point after exiting the SCWO reactor 310. In some embodiments, all or a portion of the effluent can also be recycled into the system and/or released into the environment or a water treatment facility.

[0075] Referring to FIG. 4, which depicts a block diagram of a method for using a continuous foam fractionation system to treat water contaminated with PFAS, the method may be initiated by determining a water source containing contaminants. In certain preferred embodiments, a water source that has been contaminated with PFAS is identified. For example, in some embodiments, the water source may be contaminated with PFOS or PFOA, or combinations thereof. In some embodiments of the present disclosure, the method may be used to isolate and identify whether a suspected water source does in fact contain PFAS.

[0076] As shown in FIG. 4, method 400 beings at step 402. At step 402, the method includes providing a feed stream to an inlet of an active column. In some embodiments, the feed stream can include a PFAS contaminant. In some embodiments, the feed stream may predominately include water or an aqueous solution. In certain embodiments, the feed stream may include organic contaminants, inorganic contaminants, or combinations thereof. In certain embodiments, the feed stream may include one or more additives. For example, the feed stream can include additives allowing for the feed stream to be at a set pH. In another example, the feed stream can include additives that allow for the feed stream to have a particular ionic strength.

[0077] At step 404, the method includes introducing the feed stream into an interior of the active column. For example, in such an embodiment, the feed stream can be housed within a column for foam fractionation. At step 406, the method includes flowing gas through a base of the active column into the interior of the active column. In some embodiments, the gas may be introduced via a porous gas nozzle. In certain embodiments, the gas may be introduced via a venturi device where the compressed gas drives water flow, which in turn can mix the gas and water streams. In other embodiments, the gas may be introduced via a water vacuum pump device where water flow generates suction that introduces gas stream into a water stream. Moreover, in some embodiments, the gas can be introduced near an impeller, a mixer, or a combination thereof to generate gas-water mixing.

[0078] The gas, in certain embodiments, may be compressed air, oxygen, nitrogen, carbon dioxide, or combinations thereof. In some embodiments, the gas may be any gaseous phase chemical composition that will allow for contaminant adsorption on the surface of gas bubbles of the gas.

[0079] At step 408, the method includes, as a result of the flowing of the gas into the interior of the active column, rising gas through the feed stream in the interior of the active column to form gas bubbles in the feed stream.

[0080] At step 410, as a result of the gas bubbles in the feed stream, the method includes forming a foam layer. In some embodiments, the foam layer is situated atop the feed stream in the interior of the active column. In certain embodiments, the foam layer can include at least a part of the PFAS contaminant that was initially present in the feed stream. After the foam layer is formed, in some embodiments, the interior of the active column can include both the foam layer and a purified stream, where the purified stream is the result of the PFAS contaminant being removed from the feed stream.

[0081] At step 412, the method includes passing the purified stream into a next column. In some embodiments, the next column operates as the active column and the purified stream operates as the feed stream.

[0082] Following, at decision block 414, the method progresses to determine whether the solution flowing through the system as the filtered stream contains a sufficiently low level of contaminant to result in a cleaned stream. In some embodiments, the decision block 414 determinations are decided prior to the construction of a system for conducting the method 400. In such an embodiment, the calculation of the quantity of PFAS contaminant removed at each column can be performed. In this embodiment, based on the calculation, the system is designed to contain the number of columns that will achieve a cleaned stream containing a sufficiently low level of contaminant. Such an embodiment will have a static number of columns that the feed stream and/or filtered stream will pass through in the system.

[0083] If the decision at block 414 is negative (i.e., the purified stream contains an amount of PFAS that may pose a health risk or is greater than a pre-determined amount of PFAS contaminant), then the method restarts at step 404.

[0084] If the decision at block 414 is affirmative (i.e., there is a sufficiently minimal amount of PFAS remaining in the purified stream such that the water in the stream does not pose either a health risk or is less than a pre-determined amount of PFAS contaminant), then the method continues to step 416. In some embodiments, as the number of columns in the system performing the method is predetermined, the decision at block 414 does not change the architecture of the system performing method 400.

[0085] At step 416, the method includes collecting the foam layer. At step 418, the method includes disposing of the foam layer.

[0086] FIG. 5 depicts a diagram of a modular system that allows for flexibility in flow and concentration based on capabilities and needs of a system, in accordance with certain embodiments of the present disclosure.

[0087] As shown in FIG. 5, the foam fractionation process may be utilized in a flexible and modular system. For example, in some embodiments and as shown in FIG. 5, the system can be physically adjusted to meet specific pre-determined needs. Such flexibility allows for adjustment without the need for expensive redesign and rebuilding of an entire foam fractionation system.

[0088] The number of systems in parallel determines the total flow capacity, as shown in FIG. 5. Further, as shown in FIG. 5, the number of systems in series determines the total concentration.

[0089] FIG. 6 depicts a diagram of a system that allows for flow routing using a plurality of inlet ports, in accordance with certain embodiments of the present disclosure.

[0090] In some embodiments, as shown in FIG. 6, the system can allow for the flow to be routed based on the use of a plurality of inlet ports, where the number of inlet ports utilized affects the flow. Further, as shown in FIG. 6, the system can allow for the concentration of the PFAS in the foam to be increased based on routing the flow from the flexible foam fractionation system through additional stages in the multistage process. Further, as shown FIG. 6, the use of multiple inlets B and the use of multi-stage connections. A through process columns with diameters X can allow for increased flow and increased concentration, respectively.

[0091] FIG. 7 depicts a diagram demonstrating the ability to increase concentration in system that allows for the modular components in a system flexible foam fractionation to be removed from a housing, in accordance with certain embodiments of the present disclosure.

[0092] In certain embodiments, the system can include modular components that may be freely movable, such that the modular components allow portions of the foam fractionation system to be taken out of a housing and expanded in number to increase flow or concentration as needed on site. In such an embodiment, the process can involve placing the foam fractionation columns on modular skids that can be fit into housings and taken out as needed. As shown by FIG. 7, removing the foam fractionation columns and portions of the system from a particular housing may allow for increased concentration.

[0093] In some embodiments, the system for foam fractionation can include a containerized system with external skids. Such a system could be deployed to increase either concentration or flow. Further, such an embodiment can be utilized to provide temporary increase in capability. In some embodiments, the system could be utilized to progressively increase the capacity of a system as need increases. Moreover, in some embodiments, the system may increase concentration where destruction is not available to save on storage space until destruction of the PFAS contaminants is available.

[0094] FIG. 9 depicts an angled foam fractionation column, in accordance with certain embodiments of the present disclosure.

[0095] As shown earlier in respect to FIG. 1, in some embodiments, the foam fractionation columns are vertical. In such embodiments, compressed air is injected into the liquid phase at the bottom of the column, which generates a foam that rises to the top. Further, in such embodiments, as the foam travels upward, extra water may travel with it leading to a wet foam (i.e., a foam that has retained a significant amount of water).

[0096] In some embodiments, to increase effective foam fractionation, the process can produce and utilize a relatively dry foam. A dry foam can increase the efficiency of the foam fractionation because the concentration of the target molecules in the foamate is maximized when the volume of water is minimized. Moreover, drainage from bubble breakage increases solute concentrations in the foam due to the elevated solute concentrations in liquid that originates from bubbles.

[0097] Accordingly, as shown in FIG. 9, in some embodiments, the foam fractionation system can include angling of the top portion of the foam fractionation columns. As shown in FIG. 9, when the top portion of the column is installed at an angle, , the vertical distance a retained water molecule needs to travel to reach either the liquid phase or the wall of the column is decreased (L2<L1). In such an embodiment, this decrease facilitates the drainage of water from the foam, leading to more concentrated foamate. In certain embodiments, angle, , is 45 as is shown in FIG. 9. This angle can be convenient to implement since pipe fittings facilitating 45 are commercially available.

[0098] In some embodiments, the disposal of the foam layer is through the treatment of the PFAS/PFOA-contaminated foam stream using a reactive metal oxide. FIG. 10 depicts a schematic continuous process for treating PFAS/PFOA contaminated foam streams with reactive metal oxides, in accordance with embodiments of the present disclosure.

[0099] PFAS and PFOA compounds can be decomposed using calcium compounds at moderate temperatures of 300-700 C., with the reaction producing non-toxic calcium fluoride (CaF.sub.2) as a solid product. The general reaction between PFAS/PFOA compounds and calcium oxide can be described as:

PFAS/PFOA+CaO.fwdarw.CaF.sub.2+H.sub.2O+CO.sub.2+immobilized solid products

[0100] In certain embodiments, the reaction does not require elevated pressures and there is no evidence of corrosion caused by formation of hydrofluoric acid (HF).

[0101] Furthermore, the synthesis of calcium oxide (CaO) with enhanced chemical reactivity can maximize its effectiveness in PFAS destruction. Methods such as thermal decomposition of calcium hydroxide (Ca(OH).sub.2) at 400-500 C. have been established to produce highly reactive CaO, a crucial factor in efficient PFAS removal.

[0102] Accordingly, in embodiments of the present disclosure, calcium hydroxide (Ca(OH).sub.2) can serve as a decomposing agent for PFAS, and this equivalence enables the development of PFAS destruction processes using both CaO and Ca(OH).sub.2. Additionally, magnesium oxide (MgO) shares similar chemical properties with CaO, providing an alternative for PFAS removal processes. Reactive MgO can be produced through the thermal decomposition of magnesium hydroxide (Mg(OH).sub.2) at around 400-500 C., offering potential utility in PFAS elimination.

[0103] Significantly, the method of the present disclosure may operates at atmospheric pressure, eliminating the need for high-pressure equipment and associated safety concerns. Furthermore, the risk of corrosion due to hydrofluoric acid (HF) formation can be significantly reduced or eliminated. The mineralization process effectively converts fluorine into CaF.sub.2, a non-corrosive solid, negating the requirement for expensive, corrosion-resistant alloys. Beyond PFAS/PFOA treatment and destruction, this process displays the capability to decompose various toxic compounds, making it suitable for treating complex waste streams containing multiple pollutants.

[0104] A general approach to continuously treat PFAS/PFOA contaminated foam streams with reactive metal oxides is presented schematically in FIG. 10. The process, as shown in the embodiment depicted in FIG. 10, is carried out in a high temperature reactor. In some embodiments, the high temperature reactor operates at 300 to 700 C. Further, in embodiments, the high temperature reactor contains metal oxides, preferably reactive forms of CaO or MgO.

[0105] In certain embodiments, such as those where incoming stream is delivered at lower temperature, a suitable heater or heat exchanger can be used to pre-heat the foam contaminated with PFAS/PFOA and other pollutants. In other embodiments, heat may be delivered directly to the reactor. Several types of reactors can be used including packed bed, kiln (calciner) fluidized bed, or spouted bed reactors. The reaction can be carried out at any pressure, for example atmospheric or near atmospheric pressure. The effluent, pollutant-free gas stream can be released directly to atmosphere.

[0106] FIGS. 11 and 12 depicts a schematic batch process for treating PFAS/PFOA contaminated foam streams with reactive metal oxides, in accordance with embodiments of the present disclosure. Specifically, the batch treatment of PFAS/PFOA-contaminated foam is presented in FIGS. 11 and 12. In certain embodiments, the batch treatment of PFAS/PFOA-contaminated foam is a two-step process consisting of, first as shown in FIG. 11, capture of PFAS/PFOA contaminated foam, and then, second as shown in FIG. 12, the actual destruction of these compounds.

[0107] In the first step, shown schematically on FIG. 11, the foam stream from the foam fractionation processes can be introduced into a vessel containing one or more metal oxides, for example but not limited to CaO or MgO.

[0108] The vessel can be at room or slightly elevated temperature, which both allow for formation of hydroxides via reaction between metal oxide and water. In such an embodiment, the reaction can effectively convert the foam stream into a solid hydroxide mixed with PFAS/PFOA compounds as well as with other pollutant potentially present in the foam form the foam fractionation process.

[0109] In some embodiments, the foam immobilization temporarily converts the foam stream into a solid which can be further treated at a later time. Such temporary storage can be convenient for low volume from streams that can be treated periodically once sufficient quantities are collected. As the reaction between metal oxides and water is exothermic, especially of CaO is used, in some embodiments, the system and method further include the application and use of a suitable heat removal mechanism.

[0110] In the second step, shown schematically in FIG. 12, the vessel used to immobilize foam components can be connected to a second vessel, for example a reactor, containing metal oxides capable of high-temperature destruction of PFAS/PFOA. The connection, in certain embodiments, may be made using a pipe or tubing allowing for transfer of hot gases and vapors between the two vessels.

[0111] The second vessel containing fresh metal oxide, in preferred in embodiments, is heated first to temperature required for PFAS/PFOA compounds, such as for example but not limited to between approximately 300 to 700 C. Once the oxide is heated to this temperature, the oxide will be highly reactive towards PFAS/PFOA and towards other pollutants. At the same time, the oxide loses its reactivity towards water since it is at above the decomposition temperature of its hydroxide form. Accordingly, in such an embodiment, the metal oxide at high temperature acts effectively as a selective reactor/filter, reacting with pollutants but allowing for free passage of water vapor.

[0112] In some embodiments, the release of foam components previously immobilized can be realized by a controlled heating of the collection vessel. The process, for example, can release PFAS/PFOA compounds, other pollutants, water vapor, and combinations thereof.

[0113] FIG. 13 depicts an apparatus for the PFAS/PFOA mineralization, in accordance with certain embodiments of the present disclosure.

[0114] In some embodiments, and as shown in FIG. 13, the PFAS/PFOA-contaminated waste can be mixed with metal oxide and placed in a metal vessel connected with a vapor trap. In such an embodiment, tests may then be carried out using two reaction vessels connected in series. Further, in such an embodiment, the apparatus, in whole or in significant part, can operate at atmospheric pressure. Solids remaining in the vessels and vapors condensed in the cold trap may then be analyzed for PFAS/PFOA content.

[0115] As shown in FIG. 13, the PFAS/PFOA mineralization may include an electric oven. The electric oven, in some embodiments, may be capable of reaching temperatures of 600 C. The electric oven, or any exterior vessel for heating in the apparatus, may contain a stainless-steel interior vessel, which in certain embodiments contains PFAS/PFOA-contaminated waste along with CaO oxides, MgO oxides, or combinations thereof.

[0116] The apparatus may further contain venting, through for example but not limited to a ventilation stainless-steel tube, for venting water steam and the gaseous reaction products. In some embodiments, and displayed in FIG. 13, the venting tube may lead the water steam and gaseous reaction products into an operatively connected cold trap. The cold trap, as part of the apparatus shown in FIG. 13, facilitates product condensation. The cold trap, in some embodiments, can be a water-ice bath. From the cold trap, the condensed product may be collected and the non-condensable product may be vented into a fume hood.

[0117] In collected condensed product can include solid waste, which will be inorganic salt residue produced by evaporation of the aqueous solution containing PFAS/PFOA pollutants. Accordingly, in some embodiments, the pollutant-free solid reaction products may be easily disposed.

[0118] Consistent with the above disclosure, the examples of systems and methods enumerated in the following clauses are specifically contemplated and are intended as a non-limiting set of examples.

[0119] Clause 1. A method for using foam fractionation to remove a PFAS contaminant from a water source, the method includes providing a feed stream to an inlet of an active column, where the feed stream comprises the PFAS contaminant and water; introducing the feed stream into an interior of the active column; flowing gas through a base of the active column into the interior of the active column; as a result of the flowing of the gas into the interior of the active column, rising gas through the feed stream in the interior of the active column to form gas bubbles in the feed stream; as a result of the gas bubbles in the feed stream, forming a foam layer, wherein the foam layer is situated atop the feed stream in the interior of the active column, the foam layer comprises at least a part of the PFAS contaminant, and after the foam layer is formed, the interior of the active column comprises the foam layer and a purified stream; passing the purified stream into a next column, wherein the next column operates as the active column and the purified stream operates as the feed stream; continuously repeating foam fraction steps until the feed stream becomes a cleaned stream, wherein a cleaned stream comprises water and at or below a final concentration of the PFAS contaminant; collecting the foam layer; and disposing of the foam layer.

[0120] Clause 2. The method of any foregoing clause further including adding an effective amount of a surfactant to the feed stream.

[0121] Clause 3. The method of any foregoing clause further comprising, after collecting the foam layer, utilizing the foam layer as the feed stream.

[0122] Clause 4. The method of any foregoing clause further including interacting the surfactant the PFAS contaminant to create a complexing agent, where the foam layer comprises the complexing agent.

[0123] Clause 5. The method of any foregoing clause, where the PFAS contaminant in the feed stream has an initial PFAS concentration, the at least a part of the PFAS contaminant in the foam layer has removed PFAS concentration, and a remaining PFAS contaminant in the cleaned stream has a final PFAS concentration.

[0124] Clause 6. The method of any foregoing clause, where the initial PFAS concentration is equal to that of the removed PFAS concentration added to the final PFAS concentration, and where the removed PFAS concentration is greater than or equal to the final PFAS concentration.

[0125] Clause 7. The method of any foregoing clause, where the foam fractionation is continuous.

[0126] Clause 8. The method of any foregoing clause, where disposing of the foam layer comprises sending the foam layer to a supercritical water oxidation reactor.

[0127] Clause 9. The method of any foregoing clause further including releasing the cleaned stream into an environment.

[0128] Clause 10. A system for using foam fractionation to remove a PFAS contaminant from a water source, the system including a feed stream comprising water and one or more contaminants; a gas, where the gas is operable to induce a plurality of bubbles to form in the feed stream, and create a foam layer to form at and above the interface of the feed stream, where the foam layer comprises the one or more contaminants in the feed stream; and a plurality of columns, where each column in the plurality of columns comprises a feed inlet, wherein the feed inlet is configured to receive the feed stream, each column in the plurality of columns is operably configured to separate the one or more contaminants in the feed stream into a foam layer and a purified stream, each column in the plurality of columns comprises a gas inlet, wherein the gas inlet is configured to allow the gas to enter the column, each column in the plurality of the columns comprises a foam outlet, each column in the plurality of the columns comprises a feed outlet, wherein the feed outlet is configured to discharge the purified stream, and each column in the plurality of the columns is coupled to one or more other column in the plurality of the columns to allow a continuous passage of the feed stream through the plurality of columns.

[0129] Clause 11. The system of any foregoing clause, where the one or more contaminants comprise PFAS.

[0130] Clause 12. The system of any foregoing clause, where the foam outlet is operatively connected to a foam storage tank.

[0131] Clause 13. The system of any foregoing clause, where the foam storage tank is operatively connected to a device for destroying the one or more contaminants.

[0132] Clause 14. The system of any foregoing clause further comprising a supercritical water oxidation reactor.

[0133] Clause 15. The system of any foregoing clause further comprising a removal device for removing at least a portion of the foam layer from each column in the plurality of columns.

[0134] Clause 16. The system of any foregoing clause, where the feed inlet is configured to introduce the feed stream into each column in the plurality of columns through an upper region of each column in the plurality of columns.

[0135] Clause 17. The system of any foregoing clause, where the feed outlet is configured to introduce the discharge stream into each column in the plurality of columns through a lower region of each column in the plurality of columns.

[0136] Clause 18. A method for using foam fractionation to remove a PFAS contaminant from a water source, the method including selecting a feed stream, where the feed stream comprises the PFAS contaminant and water; providing the feed stream to a column, where the column is operatively connected to a series of fractionation columns, the series of fractionation columns perform continuous foam fractionation, and the column and each fractionation column in the series of fractionation columns operate at an operating pressure, where the operating pressure is identical between the column and each fractionation column in the series of fractionation columns; super-saturating the feed stream with air; resultant from the operating pressure of the column, generating a plurality of bubbles in the feed stream; resultant from the generating of a plurality of bubbles, creating a foam layer; collecting the foam layer; and passing the foam layer through a supercritical water oxidation reactor.

[0137] Clause 19. The method of any foregoing clause further comprising adding an effective amount of a surfactant to the feed stream.

[0138] Clause 20. The system of any foregoing clause further comprising, after collecting the foam layer, discharging a cleaned stream from a final column in the series of fractionation columns.

[0139] Clause 21. The system of any foregoing clause, where the PFAS contaminant in the feed stream has an initial PFAS concentration, the foam layer has a removed PFAS concentration, and the cleaned stream has a final PFAS concentration.

[0140] Clause 22. The system of any foregoing clause, where the initial PFAS concentration is equal to that of the removed PFAS concentration added to the final PFAS concentration, and where the removed PFAS concentration is greater than or equal to the final PFAS concentration.

[0141] Clause 23. The method of any foregoing clause further comprising releasing the cleaned stream into an environment.

[0142] Clause 24. A flexible and modular system for utilizing foam fractionation to remove a PFAS contaminant from a water source, the system including a feed stream including water and one or more contaminants; a gas, operable to induce a plurality of bubbles to form in the feed stream, and create a foam layer at and above the interface of the feed stream, where the foam layer includes the one or more contaminants in the feed stream; a plurality of foam fractionation columns, where each column in the plurality of columns includes a feed inlet, configured to receive the feed stream, each column is operably configured to separate the one or more contaminants in the feed stream into a foam layer and a purified stream, each column includes a gas inlet, configured to allow the gas to enter the column, each column includes a foam outlet, each column includes a feed outlet, configured to discharge the purified stream, each column is coupled to one or more other columns to allow a continuous passage of the feed stream through the plurality of columns, and the system is configurable in a variety of arrangements; a plurality of inlet ports, where the system allows for the flow to be routed based on the use of the plurality of inlet ports; and a plurality of modular components, where the plurality of modular components are configured to be removed from a housing to allow for increased concentration.

[0143] Clause 25. The system of any foregoing clause, where one or more foam fractionation columns in the plurality of foam fractionation columns are connected in parallel.

[0144] Clause 26. The system of any foregoing clause, where the plurality of foam fractionation columns include a number of foam fractionation systems, where the number of foam fractionation systems are physically adjustable to meet a pre-determined need.

[0145] Clause 27. The system of any foregoing clause, where the plurality of foam fractionation columns includes a number of foam fractionation systems, where a width established by the number of foam fractionation systems determines the total flow capacity.

[0146] Clause 28. The system of any foregoing clause, where the plurality of foam fractionation columns includes a number of foam fractionation systems, where the number of foam fractionation systems in series determines the total degree of water purification.

[0147] Clause 28. The system of any foregoing clause, where the plurality inlet ports are configured to affect the flow and increase concentration of the one or more contaminants in the foam layer.

[0148] Clause 30. The system of any foregoing clause, where the plurality of foam fractionation columns are oriented to route the flow through additional stages in the multistage process, where the routing allows for increased flow and increased concentration.

[0149] Clause 31. The system of any foregoing clause, where the modular components are freely movable.

[0150] Clause 32. The system of any foregoing clause, where the modular components allow for one or more foam fractionation columns in the plurality of foam fractionation columns to be taken out of a housing.

[0151] Clause 33. The system of any foregoing clause, where the modular components are operatively configured to be received by skids that fit into containers, where the skids are removable from the containers.

[0152] Clause 34. The system of any foregoing clause, where removing the foam fractionation columns and portions of the system from a housing allows for increased concentration.

[0153] Clause 35. The system of any foregoing clause, further including a containerized system with external skids.

[0154] Clause 36. The system of any foregoing clause, where the containerized system with external skids are configured to be deployed to increase either concentration or flow.

[0155] Clause 37. The system of any foregoing clause, where the containerized system provides a temporary increase in capability.

[0156] Clause 38. The system of any foregoing clause, where the containerized system progressively increases the capacity as need increases.

[0157] Clause 39. An angled foam fractionation column for removing one or more PFAS contaminants from a water source, the column comprising: a feed inlet configured to receive a feed stream comprising water, one or more PFAS contaminants, and an effective amount of a surfactant, wherein the surfactant interacts with the PFAS contaminant to form a complexing agent facilitating the removal of light PFAS; a gas inlet configured to allow the entry of a gas operable to induce a plurality of bubbles in the feed stream and create a foam layer at and above the interface of the feed stream, wherein the foam layer comprises the complexing agent and the one or more contaminants; a foam outlet for discharging the foam layer; a feed outlet configured to discharge a purified stream; and a top portion angled at an angle () with respect to the vertical axis of the column, wherein the angled top portion decreases the vertical distance a retained water molecule needs to travel, facilitating the drainage of water from the foam and resulting in a more concentrated foamate.

[0158] Clause 40. The angled foam fractionation column of any foregoing clause, where the angle () of the top portion is approximately 45 degrees to optimize the drainage of water from the foam.

[0159] Clause 41. The angled foam fractionation column of any foregoing clause, where the angling of the top portion results in minimizing the volume of water retained in the foam, thereby producing a relatively dry foam.

[0160] Clause 42. The angled foam fractionation column of any foregoing clause, where the production of a relatively dry foam increases the concentration of the target PFAS contaminants in the foamate.

[0161] Clause 43. The angled foam fractionation column of any foregoing clause, where the increased concentration of PFAS contaminants in the foamate is facilitated by the elevated solute concentrations in the liquid that originates from bubble breakage.

[0162] Clause 44. The angled foam fractionation column of any foregoing clause further including a mechanism for injecting compressed air into the liquid phase at the bottom of the column to generate foam.

[0163] Clause 45. The angled foam fractionation column of any foregoing clause, where the compressed air induces a plurality of bubbles in the feed stream, creating a foam layer at and above the interface of the feed stream.

[0164] Clause 46. The angled foam fractionation column of any foregoing clause, where the foam layer comprises a complexing agent formed by the interaction of the surfactant and the one or more PFAS contaminants, facilitating the removal of light PFAS.

[0165] Clause 47. The angled foam fractionation column of any foregoing clause, where the decreased vertical distance a retained water molecule needs to travel due to the angled top portion facilitates the drainage of water, leading to a more concentrated foamate.

[0166] Clause 48. The angled foam fractionation column of any foregoing clause, where the column is part of a system comprising a plurality of such columns, each coupled to one or more other columns allowing continuous passage of the feed stream and comprising ports for surfactant addition located throughout various columns to optimize the volume of foam produced in each stage and ensure sufficient surfactant presence.

[0167] Clause 49. A system for using foam fractionation to remove a PFAS contaminant from a water source, the system comprising a feed stream comprising water, one or more PFAS contaminants, and an effective amount of a surfactant, wherein the surfactant interacts with the PFAS contaminant to form a complexing agent facilitating the removal of light PFAS; a gas, operable to induce a plurality of bubbles in the feed stream and create a foam layer at and above the interface of the feed stream, wherein the foam layer comprises the complexing agent and the one or more contaminants; a plurality of columns, wherein each column comprises a feed inlet configured to receive the feed stream and a gas inlet configured to allow the gas to enter, each column is operably configured to separate the contaminants into a foam layer and a purified stream, each column comprises a foam outlet and a feed outlet configured to discharge the purified stream, each column is coupled to one or more other columns allowing continuous passage of the feed stream, the plurality of columns comprise a plurality of ports for surfactant addition, wherein the plurality of ports are located throughout various columns in the plurality of columns to optimize the volume of foam produced in each stage and ensure sufficient surfactant presence, and the plurality of ports for adding surfactants are installed in a configuration enabling the addition of surfactants at different columns, such as every other column.

[0168] Clause 50. The system of any foregoing clause, where the system is adaptable to incorporate different surfactant amounts and/or types at different points, enabling the addition of more columns for enhanced separation.

[0169] Clause 51. The system of any foregoing clause, where at least one column in the plurality of columns comprises an angled top portion, where the angled top portion is disposed at an angle () with respect to the vertical axis of the column, facilitating the drainage of water from the foam and resulting in a more concentrated foamate; the decrease in vertical distance a retained water molecule needs to travel due to the angled top portion enhances the efficiency of foam fractionation by maximizing the concentration of target molecules in the foamate; and the angle () is configured to minimize the volume of retained water in the foam, thereby producing a relatively dry foam and increasing solute concentrations in the foamate from the drainage of bubble breakage; and

[0170] Clause 52. The system of any foregoing clause, wherein the angle () is approximately 45 degrees.

[0171] Clause 53. A method for continuous capture and destruction of PFAS compounds from foam streams using metal oxides, the method including providing a foam stream, where the foam stream comprises one or more PFAS contaminants; introducing the foam stream into a high-temperature reactor; introducing a metal oxide into the high-temperature reactor; reacting the foam stream with the metal oxide in the high-temperature reactor; as a result of the reaction, producing a purified gas stream, and forming immobilized solid products, where the immobilized solid products comprise at least one of the one or more PFAS contaminants; collecting the immobilized solid products; and disposing of the immobilized solid products.

[0172] Clause 54. The method of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 under an air atmosphere.

[0173] Clause 55. The method of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 under an inert gas atmosphere.

[0174] Clause 56. The method of any foregoing clause, where the inert gas atmosphere includes nitrogen, argon, or a combination thereof.

[0175] Clause 57. The method of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 under vacuum conditions.

[0176] Clause 58. The method of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 over a period of at least one minute.

[0177] Clause 59. The method of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 at moderate temperatures within a range of approximately 400 C. to 500 C. over a period of one minute.

[0178] Clause 60. The method of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO as the metal oxide under an air atmosphere.

[0179] Clause 61. The method of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO under an inert gas atmosphere.

[0180] Clause 62. The method of any foregoing clause, where the inert gas atmosphere includes nitrogen, argon, or a combination thereof.

[0181] Clause 63. The method of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO under vacuum conditions.

[0182] Clause 64. The method of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO over a period of at least one minute.

[0183] Clause 65. The method of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO at moderate temperatures within a range of approximately 400 C. to 500 C. over a period of one minute.

[0184] Clause 66. The method of any foregoing clause, where the vessel includes a packed bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0185] Clause 67. The method of any foregoing clause, where the vessel includes a fluidized bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0186] Clause 68. The method of any foregoing clause, where the vessel includes a spouted bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0187] Clause 69. The method of any foregoing clause, where the vessel includes a kiln with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0188] Clause 70. The method of any foregoing clause, where the non-toxic product includes a non-toxic calcium fluoride (CaF.sub.2).

[0189] Clause 71. The method of any foregoing clause, where the non-toxic product includes a non-toxic magnesium fluoride (MgF.sub.2).

[0190] Clause 72. The method of any foregoing clause, where the operating temperature is in the range of approximately 300 C. to approximately 700 C.

[0191] Clause 73. A method for batch process capture and destruction of PFAS compounds from foam streams using metal oxides, the method including providing a foam stream, where the foam stream includes water and a PFAS contaminant; introducing the foam stream into a collection vessel, where the collection vessel includes an inlet for receiving the foam stream, an outlet for transporting the contents of the collection vessel to a reactor, where the reactor is operatively configured to receive the contents of the collection vessel, and an interior housing containing a metal oxide; conducting a first reaction at a temperature suitable for forming hydroxides between the metal oxide and the water in the foam stream; resultant to the first reaction, immobilizing the foam components on the metal oxides to form immobilized foam components; pre-heating the reactor to an operating temperature, where the operating temperature renders the metal oxide highly reactive towards the PFAS contaminant; after the pre-heating of the reactor, gradually heating the immobilized foam components in the collection vessel to the operating temperature; transporting the immobilized foam components from the collection vessel to the reactor; conducting a second reaction in the reactor, where the second reaction causes the destruction of the PFAS contaminant; collecting a purified gas stream resulting from the destruction of the PFAS contaminant through the second reaction; and releasing the purified gas from the reactor.

[0192] Clause 74. The method of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 under an air atmosphere.

[0193] Clause 75. The method of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 under an inert gas atmosphere.

[0194] Clause 76. The method of any foregoing clause, where the inert gas atmosphere includes nitrogen, argon, or a combination thereof.

[0195] Clause 77. The method of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 under vacuum conditions.

[0196] Clause 78. The method of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 over a period of at least one minute.

[0197] Clause 79. The method of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 at moderate temperatures within a range of approximately 400 C. to 500 C. over a period of one minute.

[0198] Clause 80. The method of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO as the metal oxide under an air atmosphere.

[0199] Clause 81. The method of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO under an inert gas atmosphere.

[0200] Clause 82. The method of any foregoing clause, where the inert gas atmosphere includes nitrogen, argon, or a combination thereof.

[0201] Clause 83. The method of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO under vacuum conditions.

[0202] Clause 84. The method of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO over a period of at least one minute.

[0203] Clause 85. The method of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO at moderate temperatures within a range of approximately 400 C. to 500 C. over a period of one minute.

[0204] Clause 86. The method of any foregoing clause, where the vessel includes a packed bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0205] Clause 87. The method of any foregoing clause, where the vessel includes a fluidized bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0206] Clause 88. The method of any foregoing clause, where the vessel includes a spouted bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0207] Clause 89. The method of any foregoing clause, where the vessel includes a kiln with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0208] Clause 90. The method of any foregoing clause, where the non-toxic product includes a non-toxic calcium fluoride (CaF.sub.2).

[0209] Clause 91. The method of any foregoing clause, where the non-toxic product includes a non-toxic magnesium fluoride (MgF.sub.2).

[0210] Clause 92. The method of any foregoing clause, where the operating temperature is in the range of approximately 300 C. to approximately 700 C.

[0211] Clause 93. The method of any forgoing clause, where the metal oxide comprises commercially available CaO.

[0212] Clause 94. The method of any forgoing clause, where the metal oxide comprises commercially available MgO.

[0213] Clause 95. The system of any forgoing clause, where the metal oxide comprises commercially available CaO.

[0214] Clause 96. The system of any forgoing clause, where the metal oxide comprises commercially available MgO.

[0215] Clause 97. A method for the destruction of PFAS compounds, the method including introducing a metal oxide into a vessel, where the vessel is heated to a temperature in a range of approximately 300 C. to approximately 700 C.; introducing a contaminated stream to the vessel, where the contaminated stream comprises one or more PFAS compound; reacting the contaminated stream with the metal oxide; and resultant to the reacting, producing a solid non-toxic product.

[0216] Clause 98. The method of any foregoing clause, where the metal oxide includes CaO, where the CaO is produced by the thermal decomposition of Ca(OH).sub.2 under an air atmosphere.

[0217] Clause 99. The method of any foregoing clause, where the metal oxide includes CaO, where the CaO is produced by the thermal decomposition of Ca(OH).sub.2 under an inert gas atmosphere.

[0218] Clause 100. The method of any foregoing clause, where the inert gas atmosphere includes nitrogen, argon, or a combination thereof.

[0219] Clause 101. The method of any foregoing clause, where the metal oxide includes CaO, where the CaO is produced by the thermal decomposition of Ca(OH).sub.2 under vacuum conditions.

[0220] Clause 102. The method of any foregoing clause, where the metal oxide includes CaO, where the CaO is produced by the thermal decomposition of Ca(OH).sub.2 over a period of at least one minute.

[0221] Clause 103. The method of any foregoing clause, where the metal oxide includes CaO, where the CaO is produced by the thermal decomposition of Ca(OH).sub.2 at moderate temperatures within the range of approximately 400 C. to 500 C. over a period of one minute.

[0222] Clause 104. The method of any foregoing clause, where the metal oxide includes MgO, where the MgO is used as the metal oxide under an air atmosphere.

[0223] Clause 105. The method of any foregoing clause, where MgO is used as the metal oxide under an inert gas atmosphere.

[0224] Clause 106. The method of any foregoing clause, where the inert gas atmosphere includes nitrogen, argon, or a combination thereof.

[0225] Clause 107. The method of any foregoing clause, where MgO is used as the metal oxide under vacuum conditions.

[0226] Clause 108. The method of any foregoing clause, where MgO is used as the metal oxide produced by thermal decomposition over a period of at least one minute.

[0227] Clause 109. The method of any foregoing clause, where MgO is used as the metal oxide at moderate temperatures within the range of approximately 400 C. to 500 C. over a period of one minute.

[0228] Clause 110. The method of any foregoing clause, where the vessel includes a packed bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0229] Clause 111. The method of any foregoing clause, where the vessel includes a fluidized bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0230] Clause 112. The method of any foregoing clause, where the vessel includes a spouted bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0231] Clause 113. The method of any foregoing clause, where the vessel includes a kiln with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0232] Clause 114. The method of any foregoing clause, where the non-toxic product includes a non-toxic calcium fluoride (CaF.sub.2).

[0233] Clause 115. The method of any foregoing clause, where the non-toxic product includes a non-toxic magnesium fluoride (MgF.sub.2).

[0234] Clause 116. The method of any foregoing clause, where the contaminated stream includes PFAS-contaminated solid waste.

[0235] Clause 117. The method of any foregoing clause, where the contaminated stream includes PFAS-contaminated gaseous or vapor waster.

[0236] Clause 118. The method of any foregoing clause further including, prior to introducing the metal oxide and the contaminated stream into the vessel, pre-mixing the metal oxide with the contaminated stream.

[0237] Clause 119. A system for the destruction of PFAS compounds, the system including a vessel including an inlet to receive a contaminated stream, where the contaminated stream includes a PFAS compound, an interior to house the contaminated stream, and one or more outlets configured to allow solid product removal and steam removal from the vessel; a metal oxide, where the metal oxide is housed within the interior of the vessel, the metal oxide has enhanced chemical reactivity with the PFAS compound in the contaminated stream, and the metal oxide reacts with the PFAS compound at temperatures ranging from approximately 300 C. to 700 C. to produce a solid non-toxic product; and a heat source configured to heat the vessel to a reaction temperature in a range of approximately 300 C. to 700 C.

[0238] Clause 120. The system of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 under an air atmosphere.

[0239] Clause 121. The system of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 under an inert gas atmosphere.

[0240] Clause 122. The system of any foregoing clause, where the inert gas atmosphere includes nitrogen, argon, or a combination thereof.

[0241] Clause 123. The system of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 under vacuum conditions.

[0242] Clause 124. The system of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 over a period of at least one minute.

[0243] Clause 125. The system of any foregoing clause, where the metal oxide includes Ca(OH).sub.2, and the heat source is configured to produce CaO by the thermal decomposition of the Ca(OH).sub.2 at moderate temperatures within a range of approximately 400 C. to 800 C. over a period of about one minute.

[0244] Clause 126. The system of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO as the metal oxide under an air atmosphere.

[0245] Clause 127. The system of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO under an inert gas atmosphere.

[0246] Clause 128. The system of any foregoing clause, where the inert gas atmosphere includes nitrogen, argon, or a combination thereof.

[0247] Clause 129. The system of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO under vacuum conditions.

[0248] Clause 130. The system of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO over a period of at least one minute.

[0249] Clause 131. The system of any foregoing clause, where the metal oxide includes MgO, and the heat source is configured to produce MgO at moderate temperatures within a range of approximately 400 C. to 500 C. over a period of about one minute.

[0250] Clause 132. The system of any foregoing clause, where the vessel includes a packed bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0251] Clause 133. The system of any foregoing clause, where the vessel includes a fluidized bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0252] Clause 134. The system of any foregoing clause, where the vessel includes a spouted bed filled with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0253] Clause 135. The system of any foregoing clause, where the vessel includes a kiln with CaO, MgO, Ca(OH).sub.2, Mg(OH).sub.2, or combinations thereof.

[0254] Clause 136. The system of any foregoing clause, where the non-toxic product includes a non-toxic calcium fluoride (CaF.sub.2).

[0255] Clause 137. The system of any foregoing clause, where the non-toxic product includes a non-toxic magnesium fluoride (MgF.sub.2).

[0256] Clause 138. The method of any forgoing clause, where the metal oxide comprises commercially available CaO.

[0257] Clause 139. The method of any forgoing clause, where the metal oxide comprises commercially available MgO.

[0258] Clause 140. The system of any forgoing clause, where the metal oxide comprises commercially available CaO.

[0259] Clause 141. The system of any forgoing clause, where the metal oxide comprises commercially available MgO.

REFERENCES

[0260] Wang, F., L. Xingwen, L. Xiao-yan, and S. Kaimin, Effectiveness and mechanisms of defluorination of per fluorinated alkyl substances by calcium compounds during waste thermal treatment. Environmental Science and Technology, 2015. 49: p. 4672-5680. [0261] Riedel, T.P., et al., Low temperature thermal treatment of gas-phase fluorotelomer alcohols by calcium oxide. Chemosphere, 2021. 272: p. 129859. [0262] Koper, O.B., Properties of High Surface Area Calcium Oxide and its Reactivity Towards Chlorocarbons, 1996, Kansas State University. [0263] Koper, O.B., Y.X. Li, and K.J. Klabunde, Destructive Adsorption of Chlorinated Hydrocarbons on Ultrafine (Nanoscale) Particles of Calcium Oxide. Chemistry of Materials, 1993. 5: p. 500-505. [0264] Koper, O.B., Properties of High Surface Area Calcium Oxide and its Reactivity Towards Chlorocarbons, Ph.D. Thesis, 1996, Kansas State University. [0265] Koper, O.B. and K.J. Klabunde, Destructive Adsorption of Chlorinated Hydrocarbons on Ultrafine (Nanoscale) Particles of Calcium Oxide. 3. Chloroform, Trichloroethene, and Tetrachloroethene. Chemistry of Materials, 1997. 9: p. 2481-2485. [0266] Koper, O.B., S. Rajagopalan, S. Winecki, and K.J. Klabunde, Metal Oxides for Chlorocarbon and Organophosphonate Remediation, in Environmental Applications of Nanomaterials, G.E. Fryxell and G. Cao, Editors. 2012, Imperial College Press. p. 3-24. [0267] Winecki, S., Selected Environmental Applications of Nanocrystalline Metal Oxides, in Nanoscale Materials in Chemistry: Environmental Applications, L.E. Erickson, R.T. Koodali, and R.M. Richards, Editors. 2010, ACS Symposium Series. p. 77-95. [0268] Klabunde, J.K., L.E. Erickson, O.B. Koper, and R.M. Richards, Review of Nanoscale Materials in Chemistry: Environmental Applications, in Nanoscale Materials in Chemistry: Environmental Applications, L.E. Erickson, R.T. Koodali, and R.M. Richards, Editors. 2010, ACS Symposium Series. p. 1-13.