Systems and methods for encapsulating coal combustion residuals and constructing buildings and structures from coal combustion residuals

Abstract

Systems and methods for remediating coal combustion residual (CCR) deposits at a site. CCR deposits are mixed with an encapsulating material to form a CCR composite material. The CCR composite material can remain in place, be re-injected back into the site, and / or used to construct a building component.

Description

SYSTEMS AND METHODS FOR ENCAPSULATING COAL COMBUSTION RESIDUALS AND CONSTRUCTING BUILDINGS AND STRUCTURES FROM COAL COMBUSTION RESIDUALSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of United States Provisional Patent Application No. 63 / 672.590 (pending), filed on July 17, 2024, and entitled "‘SYSTEMS AND METHODS FOR ENCAPSULATING COAL COMBUSTION RESIDUALS AND CONSTRUCTING BUILDINGS AND STRUCTURES FROM COAL COMBUSTION RESIDUALS,'’ the entirety of which is incorporated herein by refence. The present application also claims the benefit of United States Provisional Patent Application No. 63 / 725,436 (pending), filed on November 26, 2024, and entitled “SYSTEMS AND METHODS FOR ENCAPSULATING COAL COMBUSTION RESIDUALS AND CONSTRUCTING BUILDINGS AND STRUCTURES FROM COAL COMBUSTION RESIDUALS,” the entirety of which is incorporated herein by refence.FIELD

[0002] The present disclosure relates to systems and methods for encapsulating coal combustion residuals. The present disclosure also relates to systems and methods for using encapsulated coal combustion residuals for beneficial uses, such as to construct buildings and other structures.BACKGROUND

[0003] In one application of coal, the coal is burned to provide the heat required to operate high-pressure steam boilers, including in coal-fired electric power plants operated by electric power utilities such as the Tennessee Valley Authority and Duke Energy. The burning of coal results in a residual particulate material called coal combustion residual ("CCR"), also referred to as “coal ash.” CCR, a solid byproduct from coal-based power plants, can include fly ash, bottom ash, boiler slag, flue gas desulfurization (FGD) solids, or combinations thereof. CCR accumulates in vast quantities in such applications. The accumulated CCR is expensive to store, and storage of CCR presents significant environmental risks. In recent years, regulatory7authorities have taken an increasingly negative view of the manner in which CCR is stored, and regulations have been put in place to require that CCR is handled in a manner different from past practices.

[0004] In the United States, the management of CCR is regulated at both the federal and state levels. The federal rules dealing with CCR include 80 Fed. Reg. § 21302 (Apr. 17. 2015), which regulates coal ash as a solid waste, but not as a hazardous waste. 80 Fed. Reg. § 21302 sets minimum standards for disposal and / or disposition of CCR. Other additional state and federal regulations also apply to CCR disposal. 80 Fed. Reg. § 21302 includes detailed standards for the design and location of CCR landfills and impoundments, groundwater monitoring, remediation, structural integrity and final closure of landfills and impoundments.

[0005] However, 80 Fed. Reg. § 21302 does not regulate practices that meet the definition of "beneficial" uses of CCR, which must meet all of the following conditions: (1) the CCR must provide a functional benefit; (2) the CCR must substitute for the use of a virgin material, conserving natural resources that would otherwise need to be obtained through practices such as extraction; (3) the use of the CCR must meet relevant product specifications, regulatory standards, or design standards when available, and when such standards are not available, the CCR is not used in excess quantities; and (4) when unencapsulated use of CCR involves placement on the land of 12,400 tons or more in non-roadway applications, the user must demonstrate and keep records, and provide such documentation upon request, that environmental releases to groundwater, surface water, soil and air are comparable to or lower than those from analogous products made without CCR, or that environmental releases to groundwater, surface water, soil and air will be at or below relevant regulatory and healthbased benchmarks for human and ecological receptors during use. In accordance with 80 Fed. Reg. at § 21349, any use of CCR that fails to comply with each of these criteria, above, will be considered to be disposal of CCR and subject to all disposal requirements in 80 Fed. Reg. § 21302. Whereas, encapsulated beneficial uses of CCR are uses that include binding the CCR into a sold matrix that minimizes mobilization of the CCR into the surrounding environment.

[0006] Accordingly, there is a need to have encapsulated formulation mix-designs which allow for a long-lasting CCR-based product that meets leachability testing standards.

[0007] One of the challenges involved in encapsulating CCR has been finding materials that can reasonably treat the millions of tons of CCR that exist on many sites. The encapsulation materials should meet desired specifications of hydraulic conductivity, leachability, compressive strength, cost, and environmental impact. While cementitious materials such as Original Portland Cement have been used to encapsulate CCR on relatively small sites, the amount Original Portland Cement required to reach the desired hydraulic conductivity, leachability’, and compressive strength throughout larger quantities of CCR has been found to be too expensive in many applications. Such large quantities of Original Portland Cement havealso been found difficult to acquire and transport to sites while also releasing undesirable quantities of carbon dioxide into the atmosphere. The amount of time that it takes to combine such quantities of such binders with the CCR has also proven undesirable.

[0008] One potential solution identified in small-scale tests is to use the process of Microbially Induced Calcite Precipitation (MICP) to create a cementitious material within the CCR. MICP is a natural process whereby many species of bacteria produce calcium carbonate when exposed to a particular environment. MICP has been studied for the past few decades as a way to improve hydraulic conductivity, leaching of heavy metals, and compressive strength. MICP materials have also been noted for potential use for carbon dioxide sequestration and the ability of "self-repair" upon being damaged by restarting the MICP reaction. Despite the potential benefits, MICP has rarely been used on full-scale projects to date and has not yet found use in soil remediation outside of limited testing scenarios. Some of the difficulties in obtaining the desired material specifications that have kept MICP largely confined to laboratory and field testing include maintaining the proper soil moisture levels throughout the addition of the MICP materials, property disbursing the MICP materials throughout the soil, and keeping the MICP reaction from reacting too quickly while the materials are still being added to the soil.

[0009] Studies on the potential of MICP to improve both soil strength and remediation efforts have been performed by Malcolm Burbank and his teams at the University of Idaho starting in 2011 with the publication of ‘‘Precipitation of calcite by indigenous microorganisms to strengthen liquefiable soir (Burbank, M._ Weaver, T., Green, T. Williams. B.. and Crawford, R, Geomicrobiology Journal). While this study showed the potential of MICP to strengthen liquifiable soils, other studies, including “Investigating the Potential for Microbially induced Carbonate Precipitation to Treat Mine Waste” (Dylan Proudfoot, Loran Brooks, Christopher H. Gammons, Edwin Barth, Diana Bless, Raja M. Nagisetty. and Ellen G. Lauchnor, Journal of Hazardous Materials, 2021), have demonstrated the ability of MICP to decrease the mobility of various pollutants. However, a number of challenges of performing MICP in CCR for practical improvement remained. These studies, like many others, focused on using indigenous microbes to perform the MICP reaction. This is due to the fact that many bacteria inhabiting a wide range of soils are capable of preforming the MICP reaction, and thus, the vast majority of soils have a substantial population of MICP capable microbes already present. Such conditions require only the addition of calcium and urea to initiate the MICP reaction. Ash of various kinds including CCR, however, is different from most of the soils that MICP has been tested on in that it generally contains few microorganisms, nor organic compounds for them to survive on, as a result of the firing process. As such, for MICP enhancement of ash, exogenousbacteria capable of performing MICP must be added. Treatment with exogenous bacteria has been studied with various soils but comes with a few additional challenges. Growing or transporting the large bacteria quantities to a site to be treated is no easy feat, but proposed solutions to meet this challenge include growing the bacteria on site via mobile bioreactors (WO2021245627A1). However, properly mixing the live bacteria into the soil has remained a difficult process. Some studies have explored the use of MICP in ash; however, they have primarily focused on its effect on Municipal Solid Waste derived fly-ash. Such studies including “Effect of Microbially Induced Calcium Carbonate Precipitation Treatment on the Solidification and Stabilization of Municipal Solid Waste Incineration Fly Ash (MSWI FA) - Based Materials Incorporated with Metakaolin’' (Mengzhu Song, Tian Lan, Yuan Meng, Tongyao Ju, Zhehong Chen, Pengfei Shen, Yufeng Du. Yongchi Deng, Siyu Han, Jianguo Jiang, Chemosphere, 2022) and “Stabilization of Fly Ash Using Cementing Bacteria. Assessment of Cementation and Trace Element Mobilization” (Isabel Gonzalez, Maria Auxiliadora Vazquez, Antonio J. Romero-Baena, and Cinta Barba-Brioso, Journal of Hazardous Materials, 2017) further demonstrate the ability of MICP to remedy some leaching problems but constitute a very different base material and setting for instituting MICP. The very few studies that have examined the effects of MICP on effectively pure CCR have only done so at very small scales in laboratory' settings. For example, “Enhancement of Coal Ash Compressibility Parameters Using Microbial-Induced Carbonate Precipitation” (Brina M. Montoya, Shahin Safavizadeh. and Mohammed A. Gabr. Journal of Geotechnical and Geoenvironmental Engineering, 2019) used approximately five cubic inches of CCR at a time. The study involved testing very' specific mixes of materials comprising CCR. The CCR was saturated with more than double its liquid limit, causing thorough liquefaction. This cannot be done throughout reasonably large areas of effect in the field as it greatly destabilizes the CCR and would be very dangerous. After thoroughly liquifying the CCR, the researchers slowly passed a large amount of MICP treatment solution across one inch of CCR at low pressure. Such a slow process is not viable for realistic use cases of MICP in CCR.

[0010] Accordingly, there is a need to for methods of successfully distributing MICP into CCR to encapsulate the CCR, while controlling moisture content and reaction timing, in applications at industrial scale sites.BRIEF SUMMARY

[0011] The present disclosure includes a method of remediating coal combustion residual (CCR) deposits at a site. The method includes mixing CCR with an encapsulating material to encapsulate the CCR with the encapsulating material, forming encapsulated CCR.

[0012] The present disclosure includes a CCR site including a CCR stack having a low moisture content area and a high moisture content area. Gypsum sis incorporated into the high moisture content area. The gypsum may be in the form of a gypsum base at a base of the CCR stack. A vertical groundwater barrier can be positioned above the gypsum base.

[0013] The present disclosure includes CCR encapsulated throughout at the particulate level, encapsulated in bulk via surrounding hydraulic barriers, or combinations thereof. Additional wastes can be encapsulated with the CCR.

[0014] The present disclosure includes an encapsulated CCR material, The material includes CCR and an encapsulating material encapsulating the CCR.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] So that the manner in which the features and advantages of the systems and methods of the present disclosure may be understood in more detail, a more particular description briefly summarized above may be had by reference to the embodiments thereof which are illustrated in the appended drawings that form a part of this specification.

[0016] FIG. 1 depicts a pumped storage hydro facility with MICP encapsulated CCR coated with a biopolymer coating, a biopolymer base, and biopolymer impoundment for the upper reservoir in accordance with embodiments of the present disclosure.

[0017] FIG. 2 depicts a CCR site near a natural water source, showing the water table, soil, and CCR content.

[0018] FIG. 3 depicts a CCR site with gypsum and a cement base.

[0019] FIG. 4 depicts a CCR site with gypsum, a cement base, and a biogeopolymer layer.

[0020] FIG. 5 depicts a CCR site with gypsum base and a biogeopolymer layer.

[0021] FIG. 6 depicts a CCR site with gypsum aggregate and a biogeopolymer layer.

[0022] FIG. 7 is a flow chart of a method of encapsulating CCR.

[0023] FIG. 8 is a CCR encapsulated in a bulk matrix material.

[0024] FIG. 9 is CCR coated with an encapsulating material.

[0025] FIGS. 10, 11, and 12 depict exemplary structures made at least partially of encapsulated CCR.

[0026] FIGS. 13A-13C depict a process for removing CCR, encapsulating the CCR, and replacing the encapsulated CCR at a site.

[0027] FIGS. 14A-14C depict a process for injecting an encapsulating material into CCR at a site to form encapsulated CCR at the site.

[0028] Systems and methods according to present disclosure will now be described more fully with reference to the accompanying drawings, which illustrate various exemplary embodiments. Concepts according to the present disclosure may. however, be embodied in many different forms and should not be construed as being limited by the illustrated embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough as well as complete and will fully convey the scope of the various concepts to those skilled in the art and the best and preferred modes of practice.DETAILED DESCRIPTION

[0029] Certain aspects of the present disclosure include systems and methods for encapsulating CCR. The present disclosure also relates to systems and methods for using the encapsulated CCR in beneficial applications, such as for constructing buildings and other structures. By encapsulating CCR and then using the encapsulated CCR, the systems and methods disclosed herein provide for the remediation of CCR deposits in novel manners that include, but are not limited to, mere containment of the CCR.

[0030] The methods include mixing CCR deposits with an encapsulating material to form an encapsulated CCR, also referred to herein as a CCR composite material. The CCR composite material can remain in place at the site; be extracted, formed, and replaced back into the site, and / or be used to construct a building component or other useful and beneficial structure. The CCR composite material can be used in a manner that qualifies as a beneficial use under 80 Fed. Reg. §21349, or can be formed solely as ameans of CCR containment and / or disposal.Encapsulating Materials - Geopolymers

[0031] The systems and methods disclosed herein include encapsulation of CCR in an encapsulating material. In some embodiments, the encapsulating material has a low permeability, low leachability, sufficient structural strength for constructing buildings and other structures, or combinations thereof. In some embodiments, the encapsulating material has a permeability of less than lxlOE-4 cm / s. or less than lxl0E-5, or less than lxlOE-6. In some embodiments, the encapsulating material has aleachabihty that meets or exceeds relevantregulatory' requirements. In some embodiments, the structural strength of the encapsulating material can be tailored to the particular application.

[0032] The encapsulating material can be geopolymer. The geopolymer can be an inorganic polymer formed by chemical reaction of material containing aluminosilicate, such as fly ash with an alkaline activator, such as sodium hydroxide and sodium silicate. The geopolymer can include a mixture of alkaline liquid blended with high silica and aluminum CCR to form a non-Portland cement. The mixture of the geopolymer can include lime to speed up curing time and decrease leachability of the encapsulating material.

[0033] In some embodiments, the geopolymer is a biogeopolymer. The biogeopolymer can include a biomass produced oil with minerals mixed therein. The biogeopolymer can include bio-based components, including organic or biological additives, such as starch, lignin, cellulose, chitosan, derived from natural or renewable sources.

[0034] In some embodiments, mixing the geopolymer with the CCR includes forming (e.g., polymerizing) the geopolymer in the presence of the CCR. Constituents of the geopolymer can be mixed with the CCR and then react with aluminosilicates in the CCR to form the geopolymer, with portions of the CCR being entrapped within the geopolymer. In some embodiments, organic oils, a constituent of the biogeopolymer, react and form polymers similar to cellulose once mixed, with portions of the CCR being entrapped within the biogeopolymer.MIPC

[0035] In some embodiments, the encapsulating material is a biocement formed via MICP. The biocement formed via MICP can include a mixture of microbes, urea, and calcium to form calcium carbonate / cal cites. The MICP process can enhance soil properties including compressive strength, hydraulic conductivity, and leachability. In the MICP reaction, CaCO3 precipitates and binds with the CCR.

[0036] In some embodiments, the CCR contains few, if any, microorganisms and little, if any, organic compounds sufficient for the microorganisms to survive on (e.g., as a result of the firing process of the coal). Embodiments of the present disclosure include enhancement of the CCR to make the CCR suitable for MICP processing. For example, enhancement of the CCR can include the addition of exogenous bacteria capable of performing MICP to the CCR. In some embodiments, a Cutter Soil Mixer (CSM) is used to introduce and mix live, exogenous, MICP-capable bacteria into CCR or soils containing the CCR. While a CSM typically introduces (e.g., injects) a binder while mixing, the CSM can be modified to, instead, inject the bacteria into the CCR / soil while mixing.

[0037] Embodiments of the MICP process are performed while controlling the moisture level of the CCR / soil in order to avoid liquefaction of the CCR / soil, while also ensuring that the MICP is effectively mixed into the CCR. In addition to avoiding liquification, maintaining the moisture levels relatively low also shortens the cure time of the MICP produced biocement. In some embodiments, the MICP process is performed without dewatering, due to the undesirable costs of effluent extraction and separate remediation or disposal, apart from the CCR.

[0038] In some embodiments, a total amount of dewatering or relocating of water in a CCR site can be reduced by increasing a molar concentrations of the MICP treatment solution used. A higher than normal concentration of the MICP treatment solution of urea and calcium can be reached, in a timely manner, by heating the water needed to dissolve the chemicals of the MICP treatment solution Heating the MICP treatment solution to achieve a higher concentration. After being concentrated, the MICP treatment solution can cooled before being mixed into a reactant material (e.g., before being mixed with the CCR). Cooling the MIPC treatment solution can temporarily slow the MICP reaction after it is added to the CCR. In some embodiments the heating is to a temperature of about 60°C. In some embodiments, the cooling is to a temperature that is above the freezing point for the solution.

[0039] In making the MICP treatment solution, the dissolution of urea in water is an endothermic reaction, while the dissolution of some calcium compounds, such as calcium chloride, in water is a exothermic reaction. Urea and calcium, dissolved in water, do not react. Thus, embodiments of the methods disclosed herein provide for adding calcium (or calcium compounds) to the water before adding the urea to the water. This order of addition decreases the amount of energy needed to heat and then cool the MICP treatment solution when preparing the concentrated, chilled urea and calcium for the MICP process.MIPC - Introduction Methods

[0040] Effectively introducing the MICP treatment solutions into the CCR in situ utilizing low moisture CCR and concentrated MICP treatment solutions can include using novel infusion and / or mixing methods. Such methods are, preferably, able to mix the MICP treatment solutions into the CCR at considerable depths, such as in situations where regions of the CCR are over one hundred feet deep beneath the surface. Such infusion / mixing methods are, preferably, also capable of working in a wide range of CCR materials including all classes of fly ash, flue gas desulfurized gypsum, and common contaminants such as various soils and even municipal, industrial, and other solid wastes of various classes.

[0041] One such novel method of introducing MICP treatment solutions into CCR disclosed herein includes the use of Cutter Soil Mixing, or similar equipment, to deliver and mix the MICP treatment solutions. The Cutter Soil Mixing equipment can be a stock CSM or aCSM that is modified to improve the ahi 11 ty to effectively deliver and mix the MICP treatment solutions into the CCR. For example, CSM equipment includes a fluid pumping line. The fluid pumping line can be modified, if needed, to be usable to pump the MICP treatment solutions, such as by supplementing the fluid pumping line with additional hoses for fluid delivery to the mixing head of the CSM. Such a need for additional hoses may be to deliver the appropriate quantity of fluids at different pressures, to keep the MICP treatment solutions separate as they move to the mixing head so as keep the reaction from starting within the machine and necessitating cleaning to keep the fluid lines from clogging, or for various other reasons. Additional modifications to mixing equipment may or may not be necessary.

[0042] Another novel method of introducing MICP treatment solutions into CCR is through the use of pressurized injection. Pressurized injection can be performed using various types of bored pipes, manchette and double packer, or similar methods. While MICP treatment of soils, via injection, has been tested before, such methods have utilized low pressure and dewatering wells to cause a weak pressure gradient and slow flow of MICP materials moving only on the order of a few feet per day through very loose and high moisture soils. To rapidly and effectively treat reasonably large areas of CCR by the injection of MICP treatment solutions, the pressurized injection should provide the MICP treatment solutions quickly and across significant distances. To move the MICP solutions quickly, without necessitating dewatering where it is otherwise unnecessary the MICP treatment solutions can be put under substantial pressure. In some such embodiments, microbes that are suited for surviving higher pressures are used in the MICP solutions. Such microbes can be subjected to environmental conditions and / or selective pressure that better prepare the population of microbes for surviving in high pressure environments (such as when injected into the CCR at high pressure). For example, the most commonly used bacteria species for MICP reactions is Sporosarcina Pasteurii. Sporosarcina Pasteurii is one of many species of microbes that can enter a form of dormancy by taking on its endospore state. When bacteria are in an environment that the bacteria cannot properly function within, the bacteria can release a spore that they carry inside of them. Such spores are significantly hardier and can wait, dormant, until within a more suitable environment at which time the spores become fully functioning cells again. Some methods disclosed herein include inducing the endospore state in the microbes used in the MICP process as a means of preparing the bacterial population to better survive high-pressureinjection into the CCR. The induction the endospore state is not limited to use for surviving high-pressure injection, and can also be used in other various forms of mechanical mixing with CCR disclosed herein, such as via the Cutter Soil Mixing method.

[0043] In some embodiments the MICP treatment solutions are introduced into CCR in a manner that ensures that the MICP reaction takes place as homogenously as possible throughout the soil / CCR being treated. In some embodiments, the method include first incorporating the urea and calcium into the CCR. and then incorporating a microbial solution into the CCR after the urea and calcium have been dispersed within the CCR. In relatively high-moisture environments, the urea and calcium can be dispersed as solid pellets to dissolve in the moisture that is already present in the CCR / soil; thereby, reducing the total pre-cure moisture in the product material. One such novel method of delivering the urea and calcium as solid pellets is via the use of Cutter Soil Mixer equipment, or similar soil mixing equipment capable of delivering small solids. In such embodiments, the pelletized urea and calcium may be delivered and mixed into the soil (including at depth) via a Cutter Soil Mixer, after which the Cutter Soil Mixer (or an additional Cutter Soil Mixer or equipment with similar applicable capabilities) would return to the same area and disperse the microbial solution to begin the MICP reaction. Such a novel method of application of the urea and calcium as solids could also be applied ex situ for the same novel purposes of reducing the total pre-cure moisture of the product while ensuring the MICP reaction takes place homogenously. Such methods of introducing materials (e.g., minerals) as solid pellets can also be used to apply other materials in pelletized form via Cutter Soil Mixer and similar equipment for a variety of purposes. One such example being the novel in situ or ex situ application of solid Calcium Sulfate for the purpose of decreasing the amount of porewater present via the hydration of Calcium Sulfate into gypsum. Such Calcium Sulfate may come from the partial or total dehydration of CCR derived gypsum from on and / or off site.MICP - Reaction Timing

[0044] Another aspect of the MICP process that has posed a challenge in the past is the extremely quick onset of the reaction upon mixing of the MICP treatment solutions. While the MICP reaction can take weeks to finish and can restart years later upon damage to the product material, the MICP reaction begins essentially instantaneously when the components of the MICP treatment solutions are brought together. This quick onset of reaction can pose a challenge and result in a suboptimal product as the reaction can cause problems in the injection / mixing equipment and can stop the solutions from moving and mixing throughout the material to be treated as effectively as would otherwise be possible. To remedy such problems,embodiments of the methods disclosed herein include suing multiple independent processes to temporarily slow the MICP reaction upon first mixing of the treatment solutions.

[0045] In some embodiments, inducing an endospore state in the microbes can be used to slow the initial MICP reaction. The additional time provided by inducing such a state provides the microbes and other components of the MICP treatment solutions sufficient time to be thoroughly mixed with the other components, including with the CCR. before the calcium carbonate product of the reaction is formed and begins to precipitate and inhibit further movement.

[0046] As previously discussed, the urea and calcium solutions can be cooled, after mixing. Furthermore, the microbial solution can be cooled after growing, which can facilitate keeping the microbes alive for a longer period of time. In addition to other benefits previously discussed, the cooling of these solutions, which remain separate until use, provides for colder final MICP treatment solution, which has been found to slow the initial MICP reaction.

[0047] Another novel method by which to slow / delay the initial MICP reaction is byadding excess nutrients to the MICP treatment solutions. As the MICP bacteria predominantly initiate the ureolytic reaction in ureolytic MICP only after other food sources have been diminished, adding excess nutrients to the MIPC treatment solutions, to last for a specified amount of time after the mixing process, can temporarily slow and / or stall the initiation of the MICP reaction. This novel method can also be used to adjust the period of time before the MICP reaction begins to take place in earnest. Meanwhile, additional bacteria can be grown in place after mixing the MIPC treatment solutions with the target material to be treated. Such additional nutrients can be added at the time of treatment via their own solution or can be added into any of the component treatment solutions ahead of time. For example, there may be some benefits to adding excess nutrients to the bacterial solution and other benefits to adding the additional nutrients to the other component solutions. For example, adding the additional nutrients to the bacterial solution may help the bacteria grow faster while still having excess nutrients left over, provide a buffer period for the bacteria to survive near optimal populations if the expected time of MICP initiation is delayed, or provide other benefits. Meanwhile, adding the additional nutrients separately or with the urea or calcium solutions allows for an exact amount of nutrients to be added beforehand that will only be used by the microbes after mixing has occurred.

[0048] An further method of producing an MICP treatment solution having a temporarily slowed / delayed reaction is through the novel application of traditional cement retardants to the MICP process. Such retardants can include incorporation of sulfates such asgy psum, sulfonates such as lignosulfonates, phosphonates, and other common cement retardants into the MICP treatment solutions.

[0049] The present disclosure provides for the concept of a completely mixed MICP treatment solution that initially, temporarily reacts slowly. Such a novel product can be used for facilitate transportation of MICP treatment solutions, compatibility of MICP treatment solutions with machines, more effective mixing of MICP treatment solutions, and others purposes.

[0050] The use of novel MICP treatment methods and products disclosed herein also enable the CCR to be treated ex situ as well as in situ. The effective bulk treatment of CCR ex situ was not previously possible and is a novel concept. The effective ex situ treatment of CCR via MICP may benefit from a slower acting treatment solution that allows for the treated CCR to be handled and disposed of far more easily. It may also result in a stronger final product material as the MICP process. Such ex situ and in situ treatment as disclosed herein can be done on the same site of CCR. Such processes, alone or together, can be done on the same quantity of CCR or to combine multiple quantities of CCR.Disposal of Pollutants

[0051] The MICP process and other CCR encapsulating methods disclosed herein can be used to contain and / or dispose of pollutants, including carbon dioxide and other effluents.

[0052] For example, the MICP process and other CCR encapsulating methods disclosed herein can be used for carbon sequestration. The MICP process itself is substantially carbon-negative, while additional carbon-dioxide from other sources can be added to the CCR before encapsulation. Such a process can, for example, include the novel process of adding carbon-dioxide to the water to remain in the CCR unit and / or the MICP treatment solutions being added into the CCR. As another novel example, non-liquid carbon-dioxide could be added to the CCR and encapsulated by a non-permeable containment structure, even if the interior bulk of CCR is untreated.

[0053] The methods disclosed herein can include disposing of effluents in the CCR. For example, polluted water from other effluent producing sites, such as one or more other CCR sites or from other sections of the same CCR site requiring some dewatering to achieve the optimal moisture content for the MICP process, can be added to the CCR. Additionally, effluents from non-CCR sources can be disposed of in the CCR to be encapsulated therewith. Such a method of pollutant disposal can be used with any of the CCR encapsulation methods disclosed herein with the provision that liquid pollutants fully solidified, as liquid is not desirable, and in some cases not allowed, that liquid reside in the CCR, even if fully surroundedby a containment structure providing low hydraulicly conductive barriers. Non-CCR solid wastes can also be disposed of with the CCR via the same disposal methods.Encapsulated CCR Structures

[0054] In some embodiments the encapsulating material is used to form exterior surfaces about the CCR to entomb (encapsulate) an interior quantity of CCR. In some such embodiments, the encapsulating material surrounds an entirely of the CCR such that all surfaces of the CCR are surrounded by the encapsulating material (e.g., a cube of CCR surrounded by six connected walls of encapsulating material). In some such embodiments, biogeopolymer encapsulates the bulk of interior quantity of CCR, and the particulates of the CCR are further encapsulated on a particulate level by another encapsulating material, such as the geopolymer or MICP. In other such embodiments, the biogeopolymer encapsulates the bulk of interior quantity of CCR, and the particulates of the CCR are not further encapsulated on a particulate level.

[0055] In some embodiments the encapsulating material of MICP I biocement is used to form exterior surfaces about the CCR to entomb (encapsulate) an interior quantity of CCR. In some such embodiments, the encapsulating material surrounds an entirety of the CCR such that all surfaces of the CCR are surrounded by the encapsulating material (e.g., a cube of CCR surrounded by six connected walls of encapsulating material). In some such embodiments, MICP I biocement encapsulates the bulk of interior quantity of CCR, and the particulates of the CCR are further encapsulated on a particulate level by another encapsulating material, such as the geopolymer and / or lime. In other such embodiments, the MICP / biocement encapsulates the entirety' of the CCR on a particulate level. In some such embodiments, The CCR is further entombed in a non-CCR or partially-CCR derived material such as any variety of traditional cements, tars, and other materials. In other such embodiments, the MICP / biocement encapsulates the bulk of interior quantity of CCR, and the particulates of the CCR are not further encapsulated on a particulate level.

[0056] In some embodiments the encapsulating material of MICP / biocement, biogeopolymer, and geopolymer is used to form exterior surfaces about the CCR to entomb (encapsulate) an interior quantity of CCR. In some such embodiments, the encapsulating material surrounds an entirety of the CCR such that all surfaces of the CCR are surrounded by the encapsulating material (e.g., a cube of CCR surrounded by six connected walls of encapsulating material). In some such embodiments, the combination of MICP / biocement, biogeopolymer, and geopolymer encapsulates the bulk of interior quantity of CCR, and the particulates of the CCR are further encapsulated on a particulate level by another encapsulatingmaterial. In other such embodiments, the entirety' of the CCR is encapsulated by a combination of MICP / biocement, biogeopolymer, and geopolymer. In other such embodiments, the combination of MICP / biocement, biogeopolymer, and geopolymer encapsulates the bulk of interior quantity of CCR, and the particulates of the CCR are not further encapsulated on a particulate level.

[0057] In some embodiments the biogeopolymer is used to coat the surface of the concerned material (e.g., CCR) on a particular level in the saturation zone, and the MICP / biocement or geopolymer is used to create the entombing surfaces that surround the bulk of the CCR above the saturation zone, thus creating a multi-sided (e.g., six-sided) tomb made of any combination of the biogeopolymer, MICP / biocement, and / or geopolymer. In some such embodiments, the internal mass of CCR is further encapsulated on a particulate level.

[0058] In some embodiments, the biogeopolymer is injected at high pressure into the bulk of the CCR and mixed with the CCR and encapsulates the CCR; thereby, forming a structure in-situ at the site of the CCR deposit. Injection of the biogeopolymer can be done at any angle (vertical or horizontal).

[0059] In some embodiments, the MICP / biocement is formed by combining urease producing bacteria with urea and calcium. In some such embodiments, the bacteria and calcium are already present in the CCR, and only the urea needs to be added. In other such embodiments, the CCR is devoid of urease producing bacteria and / or biologically available calcium and requires that they be introduced into the CCR.

[0060] In some embodiments, the biocement is created by the process of Enzyme Induced Calcite Precipitation (EICP), whereby urease enzymes are directly added to the CCR, urea, and calcium mixture in place of urease producing bacteria.

[0061] In some embodiments, the MICP / biocement forming materials are injected into the CCR and mixed with the CCR and encapsulates the CCR; thereby, forming a structure in- situ at the site of the CCR deposit. Injection of the biocement forming materials can be done at any angle (vertical or horizontal).

[0062] In some embodiments, the microbes are subjected to environmental pressures in order to induce their endospore state. In some such embodiments, the endospore state of the microbes is used so that they can better survive the harsh processes of transportation, injection, and / or mixing. In other such embodiments, the endospore state of the microbes is used so that the MICP reaction is temporarily slowed so that the microbes have time to be thoroughly mixed into the CCR before they begin the MICP process in earnest.

[0063] In some embodiments, water carries the microbes, urea, and / or calcium into the CCR to be mixed. In some embodiments, the microbes are grown in a solution of nutrients. In some such embodiments, the microbial grow th solution contains an amount of urea and / or calcium to selectively breed more microbes that are best suited to producing urease and / or growing in alkaline environments.

[0064] In some embodiments, the water used to grow and / or transport the microbes into the CCR is effluent from the CCR. In some embodiments, the water used as a solvent for the nutrients, urea, and / or calcium is effluent from the CCR. In some such embodiments, the water is obtained from dewatering of the CCR.

[0065] In some embodiments, the calcium and / or urea solutions are mixed into the CCR approximately simultaneously as the microbial and / or urease solutions.

[0066] In some embodiments, a solution of additional nutrients can be added to the bacterial growth solution, the urea solution, the calcium solution and / or an additional solution. In some such embodiments the additional nutrients help the microbes to continue growing after mixing with the CCR. In other such embodiments, the additional nutrients give the microbes a food source to be preferentially used before urea, thus temporarily slowing / delaying the onset of significant urease production and the MICP reaction.

[0067] In some embodiments, the microbe, nutrient, urea, and / or calcium solutions are cooled before mixing in order to temporarily slow the MICP reaction.

[0068] In some embodiments, the nutrient, urea, and / or calcium solution(s) are heated in order to create more concentrated solutions. In some such embodiments, more concentrated solutions are preferred as to create more calcite and / or require the addition of less water to the CCR

[0069] In some embodiments, the nutrient, urea, and / or calcium solution(s) are heated to decrease the amount of time that it takes the solute to dissolve into the solvent.

[0070] The encapsulated CCR formed by any of the methods disclosed herein can be used to construct buildings and other structure. In one embodiment, the encapsulated CCR can be used to form components of a CCR-based pumped-storage hydro-electric facility, including, but not limited to, the foundation, berms, center mass, and other components of the facility. For example, the encapsulated CCR can be used to form an upper-reservoir of a pumped- storage hydro-electric facility.

[0071] Any one or more of the biogeopolymer, MICP / bio-cement, and geopolymer can be used alone or as part of a mixture with various other materials in the construction of astructure. The encapsulated CCR materials disclosed herein can be formulated to meet or exceed any groundwater or drinking water standards.

[0072] In some embodiments, lignin and / or bio-oils are added to the biogeopolymer to extend the curing time of the encapsulated CCR composite.

[0073] In some embodiments, the biogeopolymer is applied to the CCR using an atomizer. Application of the biogeopolymer using an atomizer creates a non-permeable laminate coating on the CCR particulates. In some embodiments, the atomizer is a low pressure atomizer capable of handling the minerals involved in the process.

[0074] In some embodiments, the biogeopolymer is used to construct a non-permeable vertical and / or horizontal subsurface structure in-situ via the removal and replacement of a wide range of materials from a site.

[0075] Some embodiments include the use of any combination of the biogeopolymer, MICP / bio-cement, and / or geopolymer (together or alone) to create an entombing structure to surround and encapsulate the bulk material to be contained (e.g., CCR) on top of, adjacent to, or within soil mixing, both vertically or horizontally.

[0076] While described in reference to encapsulation of CCR, the methods, systems, and encapsulating materials disclosed herein can be used to encapsulate various materials including, but not limited to, CCR, contaminated soils, hazardous materials, mine-tailings, and other contaminated materials that require encapsulation.Gypsum

[0077] Embodiments of the present disclosure include systems and methods for using gypsum in the management (e.g., containment and / or dilution) of CCR. The gypsum can be used to complete CCR projects, remediating problem constituents on site. In some embodiments, formulations, preparations, alterations, and / or applications, one or more types of gypsum, including FGD gypsum, are used for encapsulation of CCR and other waste materials. Gypsum, including processed gypsum, can be used to improve ground conditions on contaminated and / or non-contaminated sites.

[0078] The systems and methods disclosed herein may use one or more different types of gypsum. In some embodiments, the gypsum originates from FGD, a component of CCR.

[0079] The gypsum may be used in a crystalline state or an amorphous state. The gypsum can be stabilized in a crystalline state by use of binders including, but not limited to, cement, silicates, and / or aluminates, which can be used as aggregate or fill material that is unaffected by moisture that would typically cause the gypsum to enter an amorphous state. When used in a crystalline state, the gypsum crystals may be pure, contain binders forpreserving the cry stalline state, and / or contain other materials (such as urea) that are added for purposes other than preserving the crystalline state.

[0080] In some embodiments, the gypsum is chemically and / or physically altered prior to use. The gypsum may be di-hydrate, hemi-hydrous, or anhydrous gypsum. In embodiments where the gypsum is dehydrated, the gypsum may be dehydrated via calcination, mechanical dewatering methods (e.g., vacuum filters, rotary drum filters, or centrifuges), or gravity drainage and evaporation. The absorption potential of gypsum is increased by calcination, dewatering and / or grinding processes. Calcined gypsum absorbs water when placed into high moisture content areas.

[0081] In some embodiments, the gypsum is used as a reactant before or after use in the method. In other embodiments, the gypsum is not used as a reactant before or after used in the method. The gypsum may be chemically altered in situ via the addition of reactants or an electrical current.

[0082] In some embodiments, calcium (Ca) in gy psum (CaSC ) is split from sulfate (SO4) for use as a source of calcium in the methods disclosed herein. Such methods can involve both chemical and electrolytic processes preformed in situ and / or ex situ.

[0083] The gypsum can be processed to produce aggregate gypsum of various specific sizes. For example, the gypsum may be ground, pelletized, or otherwise processed to have a specific, or non-specific, particle size.

[0084] The gypsum may be used pure or as part of a mixture with other components. For example, the gypsum can be mixed with other CCR products. The gypsum may be used as a diluent to dilute any component of CCR (including pore water or CCR contaminated, nonpore water). The gypsum may be mixed with materials to form a bio-geopolymer while the gypsum is in a crystalline or amorphous state. The gypsum may be used as a diluent to allow fly ash materials (CCR) and water to be in the safe PPM for groundwater and / or drinking water standards.

[0085] The gy psum can be used for encapsulation of CCR and / or other waste material sites. The gypsum may be used to prepare a section of CCR for various forms of in situ reactions of other materials. This includes, but is not limited to, lowering moisture content, limiting the flow of water and other materials in place, and / or controlling the flow of added materials.

[0086] The gypsum can be used for ground improvement as well. For example, some embodiments of the method include the injection of calcined gypsum into high moisture subsurface area to give the ground added strength and stability.

[0087] The method disclosed herein can include using the gypsum to displace or adsorb water to create a water barrier, or to lower moisture content without necessarily creating a water barrier. The gypsum may be used to weaken a flow of water by deflecting the water, spreading the flow of water, or partially obstructing the flow of water.

[0088] In some embodiments, the gy psum is used to form a monolithic slab of pure gypsum or gypsum-based cement utilizing a variety’ of binders. The gypsum may be used to control the flow of other injected or otherwise placed materials. The gypsum may add strength to an area in or around a mass of CCR.

[0089] In some embodiments, the gy psum is from on site or is transported from off site. The gypsum can be used in situ without being moved or altered.

[0090] The gypsum can be placed into high-moisture areas to establish foundational preparations for coatings or cementitious barriers. Barriers containing other products, include but are not limited to polymers, bentonite, silanes. The gypsum can be armored to reduce or eliminate deterioration in strength values.

[0091] In some embodiments, gypsum can be added underground with mix buckets, trenching, or axis holes.

[0092] When performing in situ encapsulation of a CCR site, to efficiently use binding agents which are the costliest component of the encapsulation formulation mix design, the moisture content for the area to be in situ encapsulated is preferred to be in the 20% moisture content range. When gypsum is altered by calcination, grinding, or drying, along with any other method described in this application, once the gypsum is placed in the high moisture content area the g psum with absorb water creating a lower moisture content area for the minerals and soils which are to be in situ encapsulated. When calcined gypsum is placed in a high moisture content area it has the additional attribute in that it does not contain or release into the environment any constituents of concern.

[0093] The gypsum can also be armored such that the g psum will retain a high compressive strength and will not degrade when soaked in water. One possible application of this is for use as the bottom part of a gypsum base that is in direct contact with the groundwater, and in the manufacture of gypsum-based aggregate that is used to solidify an area. Subsequently, a different formulation of gy psum can be used to absorb water in the area directly above the armored gypsum.

[0094] With calcined gypsum not containing constituents of concerns, gy psum can be mixed with other materials, including CCR products, to dilute the amount of heavy metal released into the environment.

[0095] In some embodiments, enzyme induced calcite precipitation (EICP) is used in the method disclosed herein. For example, urease can be directly injected with urea and calcium salts, rather than being produced by a bacteria in situ.

[0096] In some embodiments, clay aggregate is used to fill each gypsum-pile hole to provide additional stability, especially for equipment.

[0097] In some embodiments, the gypsum is dehydrated to hemi-hy drate or an-hy drous calcium sulfate before being mixed with the CCR, and undergoes a hydration reaction when mixed with the CCR that converts the hemi-hydrate or an-hydrous calcium sulfate back into gypsum di-hydrate.

[0098] In some embodiments, the gypsum is crystalized by adding silicates or aluminates (optionally derived from the CCR).

[0099] In some embodiments, the gypsum is used as a source of calcium ions for the MICP reaction by being broken down via chemical reactants or electrolysis.Bottom Ash[000100] In some embodiments, bottom ash is used in the MICP treatment solutions. Bottom as has been found to provide for a stronger reaction product in MICP reactions. Additionally, bottom ash is suitable for use in relatively high-moisture environments. For example, binding CCR, which can be powder like in consistency, in an MICP reaction when the CCR site is adjacent or near a body of water can be challenging due to the high moisture content in the soil / CCR. The high moisture content can inhibit the bridging of the natural aggregates during the MICP reaction. Thus, in some embodiments, CCR aggregates, such as bottom ash, are added into the MICP reactants to reduce the overall w ater content as a function of weight percentage. Bottom ash has been found to function better than fly ash in such high- moisture environments because bottom as tends to be denser and have a larger average particle size. The bottom ash can displace the water present in the environment. A moisture content of the CCR / soil below 33% wl. is, in some embodiments, desired. Therefore, in some embodiments, when the moisture content of the CCR / soil is above 33% wt., then bottom ash is added. In some embodiments,Figures[000101] Some embodiments of the present disclosure will now be described with reference to the Figures.[000102] FIG. 1 depicts an embodiment of a structure made in accordance with the present disclosure. Structure 100 is a pumped storage hydro facility with MICP encapsulated CCR coated with a biopolymer coating. In particular, structure 100 includes MICPencapsulated CCR 102a positioned above grade (i.e., above ground level) and MICP encapsulated CCR 102b positioned below grade (i.e., below ground level). The MICP encapsulated CCR 102a and 102b is include CCR that is encapsulated via an MICP reaction on a particulate level. The MICP encapsulated CCR 102a and 102b is further encapsulated on a bulk level via a bio-geopolymer, including a bio-geopolymer base 104 and bio-geopolymer walls 106. A top surface of the structure further includes an additional bio-geopolymer laminate 108a. including a thin portion 108b. The structure 100 is shaped to form an upper reservoir 110 for containment of water.[000103] FIG. 2 depicts a CCR site 200 with a CCR stack 202 positioned proximate a river 204 and soil 206. The water table 208 at the CCR site 200 is shown, and generally corresponds with a water level of the river 204. The CCR stack 202 includes a relatively low- moisture content area 210 above the water table 208 and a relatively high-moisture content area 212 below the water table 208. The low-moisture content area 210 has a moisture content of approximately 22 wt.%. The high-moisture content area 212 has a moisture content of approximately 47 wt.%.. and is not filled with gypsum. The CCR site 200 is representative of existing site conditions with a high-moisture content areas.[000104] FIG. 3 depicts a CCR site 300 with a CCR stack 302 positioned proximate a river 304 and soil 306. The water table 308 at the CCR site 300 is shown, and generally corresponds with a water level of the river 304. The CCR stack 302 includes a relatively low- moisture content area 310 above the water table 308 and a relatively high-moisture content area 312 below the water table 308. The low-moisture content area 310 has a moisture content of approximately 22 wt.%. The high -moisture content area 312 has a moisture content of approximately 47 wt.%. The high-moisture content area 312 has been injected with gypsum 314 (e.g., armoured gypsum pre-fill). A bio-geopolymer base 316 is positioned in the high- moisture content area 312 below the water table 308. Also, a bio-geopolymer wall 318 is positioned between one side of the CCR stack 302 and the soil 306.[000105] FIG. 4 depicts a CCR site 400 with a CCR stack 402 positioned proximate a river 404 and soil 406. The water table 408 at the CCR site 400 is shown, and generally corresponds with a water level of the river 404. The CCR stack 402 includes a relatively low- moisture content area 410 above the water table 408 and a relatively high-moisture content area 412 below the water table 408. The low-moisture content area 410 has a moisture content of approximately 22 wt.%. The high-moisture content area 412 has a moisture content of approximately 47 wt.%. The high-moisture content area 412 has been injected with gypsum 414. A cement sub-floor 420 is positioned at a based of the CCR stack 402, betw een the CCRstack 402 and soil 406. The cement sub-floor 420 can be jet grouted into the gypsum 414 to form a groundwater barrier. A bio-geopolymer base 416 is positioned in the high-moisture content area 412 below the water table 408 and above the cement sub-floor 420. Also, a biogeopolymer wall 418 is positioned between one side of the CCR stack 402 and the soil 406. The bio-geopolymer base 416 can be jet grouted directly above the cement sub-floor 420 for additional environmental protection.[000106] FIG. 5 depicts a CCR site 500 with a CCR stack 502 positioned proximate a river 504 and soil 506. The water table 508 at the CCR site 500 is shown, and generally corresponds with a water level of the river 504. The CCR stack 502 includes a relatively low- moisture content area 510 above the water table 508 and a relatively high-moisture content area 512 below the water table 508. The low-moisture content area 510 has a moisture content of approximately 22 wt.%. The high -moisture content area 512 has a moisture content of approximately 47 wt.%. The high-moisture content area 512 has been injected with gypsum to form a gypsum base 514. The gy psum base is positioned between the CCR stack 502 and soil 506. A bio-geopolymer base 516 is positioned in the high-moisture content area 512 below the water table 508 and above the gypsum base 514. Also, a bio-geopolymer wall 518 is positioned between one side of the CCR stack 502 and the soil 506. The gypsum base 514 can include ground gypsum, calcined gy psum, or a combination of ground and calcined gy psum.[000107] FIG. 6 depicts a CCR site 600 with a CCR stack 602 positioned proximate a river 604 and soil 606. The water table 608 at the CCR site 600 is shown, and generally corresponds with a water level of the river 604. The CCR stack 602 includes a relatively low- moisture content area 610 above the w ater table 608 and a relatively high-moisture content area 612 below the water table 608. The low -moisture content area 610 has a moisture content of approximately 22 wt.%. The high-moisture content area 612 has a moisture content of approximately 47 wt.%. The high-moisture content area 612 has been injected with gypsum to form a gypsum aggregate 614. The gypsum aggregate 614 is positioned between the CCR stack 602 and soil 606. A bio-geopolymer base 616 is positioned in the high-moisture content area 612 below the water table 608 and above the gypsum aggregate 614. Also, a biogeopolymer wall 618 is positioned between one side of the CCR stack 602 and the soil 606. [000108] FIG. 7 depicts a flow chart of an embodiment of the methods disclosed herein. The method of remediating coal combustion residual (CCR) deposits at a site, method 700, includes mixing step 702. In mixing step 702, CCR is mixed with an encapsulating material. The mixing results in the encapsulation of the CCR with the encapsulating material, forming encapsulated CCR. The CCR can include fly ash, bottom ash, boiler slag, flue gasdesulfurization (FGD) solids, or combinations thereof. The encapsulation of the CCR can be on a bulk level, such as is show the biopolymer walls floors, ceiling, and laminate in FIG. 1. That is, a bulk portion of CCR can be surrounded by an encapsulating material. While FIG. 1 is two dimensional, showing a floor, ceiling, and two side walls, one skilled in the art would understand that the CCR deposit can be surrounded on all sides by such walls (e.g., including the surface represented by the front of the drawing page and the surface that would be on the opposing side of the front surface of the drawing page). Also, the encapsulation of the CCR can be on a particular level. As shown in FIG. 8, a matrix of the encapsulating material 802 can be formed that contains the CCR 804 (or components of the CCR that remain after an MICP reaction) therein. For example, the CCR 804 can be a distrusted phase within the matrix phase of the encapsulating material 802. Alternatively and / or additionally, as shown in FIG. 9, a coating of the encapsulating material 902 can be formed around particles and / or aggregates of CCR 904 (or components of the CCR that remain after an MICP reaction). Thus, the encapsulated CCR can be bound within a sold matrix of the encapsulating material such that mobility of the CCR is inhibited.[000109] The method 700 includes an extracting step 701 where the CCR is extracted from a CCR deposit at the site. For example, the CCR can be dug or otherwise removed from the site prior to the mixing. Alternatively, the encapsulating material can be introduced into CCR and mixed therew ith, in situ, without the extraction step, such as via use of a CSM or high pressure injection.[000110] The method 700 includes replacement step 703 in which, after mixing the CCR with the encapsulating material, the CCR is reintroduced into the site. This step would, of course, not be necessary where extraction was not performed.[000111] The method 700 includes a forming step 704 in which a structure is formed with the encapsulated CCR. The structure can be a building and / or containment structure that includes w alls, a floor, a ceiling, or combinations thereof, as shown in FIG. 1.[000112] FIG. 10 depicts an exemplary structure made of the encapsulated CCR. Building 1000 includes walls 1002. a floor 1004, and a roof 1006, each of is made, at least partially, of an encapsulated CCR 1008 in accordance with the present disclosure. The portions of the building 1000 made of the encapsulated CCR 1008 can be non-loadbearing or lightloadbearing portions of the building.[000113] FIG. 11 depicts a barrier 1100 (e g., a Jersey barrier) made, at least partially, of an encapsulated CCR 1102 in accordance with the present disclosure.[000114] FIG. 12 depicts a roadway 1200 made, at least partially, of an encapsulated CCR 1202 in accordance with the present disclosure.[000115] The encapsulated CCR disclosed herein can be used in applications where cement would typically be used (e.g., applications where high strength cement is not required). For example, the encapsulated CCR disclosed herein can be used to construct Jersey barriers, roadways, non-loadbearing or light-loadbearing walls, or other structures.[000116] FIG. 13A depicts a site 1300 having a CCR deposit 1304 at in the ground 1302. In FIG. 13B, the CCR deposit 1304 has been removed, leaving a hole 1306. In FIG. 13C, the encapsulated CCR 1308 is replaced into the hole at the site.[000117] FIG. 14A depicts a site 1400 having a CCR deposit 1404 at in the ground 1402. In FIG. 14B, an introduction device 1410 (e.g., a CSM or high-pressure injector) is introducing encapsulating material 1412 into the CCR deposit 1404 and mixing it therewith. In FIG. 14C, after the mixing is complete the CCR deposit 1404 has been converted into encapsulated CCR 1408.[000118] Although the present embodiments and advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

CLAIMSWhat is claimed is:

1. A method of remediating coal combustion residual (CCR) deposits at a site, the method comprising mixing CCR with an encapsulating material to encapsulate the CCR with the encapsulating material, forming encapsulated CCR.

2. The method of claim 1. wherein the CCR comprises fly ash. bottom ash, boiler slag, flue gas desulfurization (FGD) solids, or combinations thereof.

3. The method of claim 1, wherein the encapsulated CCR is bound within a sold matrix of the encapsulating material such that mobility of the CCR is inhibited.

4. The method of claim 1, comprising, prior to mixing the CCR with the encapsulating material, extracting the CCR from a CCR deposit at the site.

5. The method of claim 4, comprising, after mixing the CCR with the encapsulating material, replacing the CCR into the site.

6. The method of claim 4, comprising forming a structure with the encapsulated CCR7. The method of claim 6. wherein the structure comprises a wall.

8. The method of claim 6, wherein the structure comprises a floor, a ceiling, or combinations thereof.

9. The method of claim 6, wherein the structure qualifies as a beneficial use under 80 Fed. Reg. §21349.

10. The method of claim 1, wherein the CCR is mixed with the encapsulating material, in situ, at the site.

11. The method of claim 1, wherein the CCR is mixed with the encapsulating material, ex situ, remote from the site.

12. The method of claim 1, wherein the encapsulating material exhibits low permeability, low leachability, sufficient structural strength for constructing a structure, or combinations thereof.

13. The method of claim 1, wherein the encapsulating material comprises a geopolymer.

14. The method of claim 13, wherein the geopolymer comprises an inorganic polymer formed by chemical reaction of the CCR with an alkaline activator.

15. The method of claim 14, wherein the geopolymer is formed by mixing the alkaline activator with the CCR to form a non-Portland cement.

16. The method of claim 15, wherein the lime is mixed with the alkaline activator and the CCR.

17. The method of claim 13, wherein the geopolymer is a biogeopolymer.

18. The method of claim 1. wherein the encapsulating material is a biocement.

19. The method of claim 1. wherein the biocement is formed via MICP.

20. The method of claim 19, wherein the mixing of the CCR with the encapsulating material comprises mixing the CCR with an MICP treatment solution to form calcium carbonate of the biocement.

21. The method of claim 20. wherein the MICP treatment solution comprises microbes, urea, and calcium.

22. The method of claim 21, wherein the MICP treatment solution comprises exogenous bacteria.

23. The method of claim 20, comprising, prior to mixing the CCR with the MICP treatment solution, increasing a molar concentrations of the MICP treatment solution.

24. The method of claim 23, wherein increasing the molar concentrations of the MICP treatment solution comprises heating the MICP treatment solution.

25. The method of claim 24, comprising, after the heating and prior to the mixing, cooling the MICP treatment solution.

26. The method of claim 21, comprising preparing the MICP treatment solution including mixing the calcium with water and, after mixing the calcium, mixing the urea with the water.

27. The method of claim 20, wherein mixing the MICP treatment solution with the CCR includes Cutter Soil Mixing the MICP treatment solution into the CCR.

28. The method of claim 20, wherein mixing the MICP treatment solution with the CCR includes introducing the microbes, urea, and calcium separately into the CCR.

29. The method of claim 20, wherein mixing the MICP treatment solution with the CCR includes injecting the MICP treatment solution into CCR under pressure.

30. The method of claim 29, wherein, prior to the injection, a population of the microbes are subjected to high pressure conditions.

31. The method of claim 20, wherein, prior to the mixing, the microbes are in an endospore state.

32. The method of claim 20, wherein the mixing includes mixing the urea and calcium with the CCR, and, after mixing the urea and calcium with the CCR, mixing the microbes with the CCR.

33. The method of claim 32, wherein, prior to the mixing, the urea and calcium are solid pellets.

34. The method of claim 20, comprising mixing solid calcium sulfate with the CCR, wherein, after the mixing of the calcium sulfate with the CCR, hydration of the calcium sulfate into gypsum occurs.

35. The method of claim 20, comprising cooling the urea, calcium, and microbes prior to the mixing.

36. The method of claim 20, comprising incorporating nutrients into the MICP treatment solution, wherein the nutrients are nutrients that the microbes consume.

37. The method of claim 36, wherein incorporating nutrients into the MICP treatment solution delays initiation the MICP reaction.

38. The method of claim 20, comprising adding a cement retardant to the MICP treatment solution.

39. The method of claim 38, wherein the cement retardant comprises sulfates, sulfonates, phosphonates, or combinations thereof.

40. The method of claim 38, wherein the cement retardant comprises gypsum, lignosulfonates, or combinations thereof.

41. The method of claim 1, comprising incorporating pollutants into the encapsulated CCR.

42. The method of claim 41, wherein the pollutants comprise carbon dioxide, and wherein the carbon dioxide is sequestered in the encapsulated CCR.

43. The method of claim 1, comprising forming a structure from the encapsulated CCR.

44. The method of claim 43, wherein the structure encapsulates a bulk quantity of CCR45. The method of claim 44. wherein the structure comprises a floor, walls, and a ceiling.

46. The method of claim 44, wherein the structure entirely surrounds the bulk quantity of CCR.

47. The method of claim 1, comprising encapsulating a bulk quantity of CCR within a structure.

48. The method of claim 47, wherein the structure comprises a biopolymer or biocement formed via an MICP reaction with CCR, and wherein the bulk quantity’ of CCR within the structure is further encapsulated, on a particulate level, via a biopolymer or biocement formed via an MICP reaction with CCR.

49. The method of claim 20, comprising subjecting the microbes to environmental pressures to induce an endospore state.

50. The method of claim 1, comprising applying a biogeopolymer onto the CCR using an atomizer to form a non-permeable laminate coating on the CCR.

51. The method of claim 20, wherein the MICP treatment solution comprises bottom ash.

52. The method of claim 1, comprising extracting the CCR at the site prior to the mixing, and depositing the encapsulated CCR into the site after the mixing, wherein the extracting, mixing, and depositing are performed about an entire perimeter of the site such that walls made of the encapsulated CCR composite material surround the site.

53. The method of claim 52, wherein the extracting, mixing, and depositing are performed at a bottom depth of the site such that a foundation made of the encapsulated CCR is below the site.

54. The method of claim 53, wherein the extracting, mixing, and depositing are performed at a top of the site such that a cap made of the encapsulated CCR is above the site, and such that a portion of the CCR deposit is entirely surrounded by and encapsulated by the encapsulated CCR.

55. The method of claim 52, further comprising: extracting an additional portion of the CCR at the site; mixing the additional portion of the CCR with a second encapsulating material to form a second encapsulated CCR; and building a structure with the second encapsulated CCR.

56. The method of claim 1, wherein the encapsulating material comprises a polymer.

57. The method of claim 13. wherein the geopolymer comprises a mixture of alkaline liquid blended with high silica and forms a non-Portland cement when mixed with the CCR.

58. The method of claim 57, wherein the geopolymer further comprises lime.

59. The method of claim 1, wherein the encapsulating material comprises a microbiologically induced calcium carbonate precipitation (MICP) biocement.

60. The method of claim 59, wherein the MICP biocement is formed from a mixture of one or more solutions containing microbes, nutrients, urea, and calcium to form calcium carbonate.

61. The method of claim 60, wherein the one or more solutions of microbes, nutrients, urea, and calcium are cooled to a low temperature before being added to the CCR to temporarily slow the MICP reaction.

62. The method of claim 60, wherein the one ore more solutions containing the urea and calcium are heated during preparation to absorb into a minimal amount of water for production of a concentrated solution.

63. The method of claim 60, wherein the one or more solutions contain an amount of nutrients at the time of mixing with each other and the CCR to temporarily slow the MICP reaction by providing the microbes with a food source to preferentially consume before producing substantial amounts of urease to react with the urea.

64. The method of claim 60, wherein the microbes are subjected to environmental pressures in order to induce a transition to their endospore state.

65. The method of claim 64, wherein the microbes are mixed with the one or more solutions and CCR while in the endospore state for the purpose of temporarily slowing the MICP reaction.

66. The method of claim 64, wherein the microbes are induced into their endospore state to more successfully survive the transportation and mixing processes.

67. The method of claim 60, wherein the one or more solutions of microbes, nutrients, urea, and calcium solutions are injected into the CCR under pressure.

68. The method of claim 60, wherein the one or more solutions of microbes, nutrients, urea, and calcium are mechanically mixed into the CCR in situ at the site.

69. The method of claim 68, wherein the one or more solutions of microbes, nutrients, urea, and calcium are mechanically mixed into the CCR in situ via the use of mixing equipment.

70. The method of claim 69, wherein the mixing equipment comprises a Cutter Soil Mixer.

71. The method of claim 1, wherein the encapsulated CCR is used to entomb the CCR deposit by forming exterior walls that surround an interior portion of the CCR deposit.

72. The method of claim 71 , wherein the CCR in the interior of the CCR deposit is not encapsulated on a particulate level.

73. The method of claim 71, further comprising:extracting the interior portion of the CCR deposit; and mixing the extracted interior portion of the CCR deposit with a second encapsulating material to form a second encapsulated CCR.

74. The method of claim 73, wherein the second encapsulating material is the same as the encapsulating material.

75. The method of claim 73, further comprising depositing the second encapsulated CCR back into the site.

76. The method of claim 75, further comprising forming a building structure with the second encapsulated CCR.

77. The method of claim 1, wherein the encapsulated CCR surrounds an entirety of the CCR deposit such that all surfaces of the CCR deposit are surrounded by the encapsulated CCR.

78. The method of claim 1, wherein the mixing causes the encapsulating material to coat surfaces of particulates of the CCR.

79. The method of claim 1, wherein the encapsulating material is mixed with the CCR by injecting the encapsulating material at high pressure into the CCR deposit thereby forming the CCR composite material in-situ at the site.

80. The method of claim 1 , further comprising using the encapsulated CCR to form a building or other structure.

81. The method of claim 80, wherein the building comprises a pumped-storage hydro-electric facility.

82. The method of claim 80, wherein the building includes a foundation, berms, and center mass.

83. The method of claim 80, wherein the building comprises an upper-reservoir of a pumped-storage hydro-electric facility.

84. The method of claim 1, wherein the encapsulated CCR meets or exceeds groundwater or drinking water standards.

85. The method of claim 1, wherein the encapsulating material comprises a biogeopolymer mixed with lignin and / or bio-oils.

86. The method of claim 1, wherein the encapsulating material comprises a biogeopolymer, and wherein mixing the biogeopolymer with the CCR deposit comprises applying the biopolymer onto the CCR deposit using an atomizer.

87. The method of claim 86, wherein the biogeopolymer forms a non-permeable laminate coating on particulates of the CCR deposit.

88. The method of claim 1, wherein the encapsulated CCR is used to construct a non-permeable vertical and / or horizontal subsurface structure via in-situ removal and replacement of the CCR deposit.

89. The method of claim 1, wherein the encapsulating material comprises gypsum.

90. The method of claim 89, wherein the gypsum is FGD gypsum.

91. The method of claim 89, wherein the gypsum is in a crystalline state.

92. The method of claim 91, wherein the gypsum is mixed with a binder.

93. The method of claim 92, wherein the binder comprises cement, silicate, aluminate, or combinations thereof.

94. The method of claim 89, wherein the gypsum is in an amorphous state.

95. The method of claim 89. wherein the gypsum is di -hydrate, hemi -hydrous, or anhydrous gypsum.

96. The method of claim 89, further comprising dehydrating the gypsum.

97. The method of claim 96, wherein dehydrating the gypsum comprises calcination, mechanical dewatering, or gravity drainage and evaporation.

98. The method of claim 97, wherein the mechanical dewatering comprises vacuum filtering, rotary drum filtering, or centrifugal separation.

99. The method of claim 89, wherein the gypsum is calcined gy psum.

100. The method of claim 89, wherein the gypsum is used as a reactant prior to mixing with the CCR.

101. The method of claim 89, wherein the gy psum is chemically altered in situ via addition of reactants or an electrical current.

102. The method of claim 89, wherein the gypsum is chemically altered ex situ via addition of reactants or an electrical current.

103. The method of claim 89, comprising processing the gypsum to produce aggregate gypsum.

104. The method of claim 89, comprising grinding or pelletizing the gypsum.

105. The method of claim 89, wherein the gypsum is pure.

106. The method of claim 89, wherein the gypsum is part of a mixture.

107. The method of claim 106, wherein the mixture comprises CCR products.

108. The method of claim 106, wherein the mixture is or forms a bio-geopolymer.

109. The method of claim 106, wherein the mixture comprises fly ash material and water.

110. The method of claim 89, comprising positioning gypsum into a high moisture subsurface area of the site.

111. The method of claim 110, wherein the positioning comprises injecting.

112. The method of claim 110, wherein the gypsum is calcined.

113. The method of claim 110, wherein the gypsum displaces and / or adsorbs water and forms a water barrier or lower moisture content area at the site.

114. The method of claim 110. wherein the gypsum weakens a flow of water by deflecting the water, spreading the flow of water, or partially obstructing the flow of water.

115. The method of claim 89, wherein the gypsum is a monolithic slab of gypsum or gypsum-based cement.

116. The method of claim 110, wherein the gypsum is armored.

117. The method of claim 110, wherein the positioning comprises positioning gypsum at a base of the site.

118. The method of claim 117, further comprising positioning a cement groundwater barrier at the base of the site.

119. The method of claim 118, wherein the cement groundwater barrier is j et grouted into the gypsum to form a groundwater barrier.

120. The method of claim 118, further comprising positioning a vertical groundwater barrier above the cement groundwater barrier.

121. The method of claim 120. wherein the vertical groundwater barrier is a biogeopolymer vertical groundwater barrier.

122. The method of claim 118, wherein the gy psum forms a gypsum base at the site.

123. The method of claim 122. further comprising positioning a vertical groundwater barrier above the gypsum base.

124. The method of claim 122, wherein the vertical groundwater barrier is a biogeopolymer vertical groundwater barrier.

125. The method of claim 122, wherein the gy psum base comprises ground gypsum, calcined gypsum, or a combination of ground and calcined gypsum.

126. The method of claim 122. wherein the gypsum base comprises gypsum aggregate.

127. The method of claim 110, wherein the gy psum absorbs water at the site creating a lower moisture content area.

128. The method of claim 1, further comprising injecting urease, urea, and calcium at the site to initiate enzy me induced carbonate precipitation (EICP).

129. The method of claim 110. further comprising filling each gy psum-pile hole with clay aggregate.

130. The method of claim 20, wherein the urea and calcium are applied as solids.

131. The method of claim 130, wherein the urea and calcium solids are applied as solid pellets.

132. The method of claim 131, wherein the urea and calcium pellets are applied in situ via conveyance of the pellets through Cutter Soil Mixer.

133. The method of claim 131, wherein the urea and calcium pellets are added to the CCR to be dissolved by water already present in the CCR.

134. The method of claim 133, wherein the urea and calcium pellets are added to the CCR to be dissolved by water already present in the CCR for the purpose of lowering the total pre-cure moisture level of the product material.

135. The method of claim 20, wherein the urea and calcium are applied first such that they can be spread throughout the CCR before the microbial solution is added and the MICP process begins.

136. The method of claim 110, wherein the gypsum is delivered in situ as pellets via a Cutter Soil Mixer.

137. The method of claim 136, wherein the gy psum is applied for the purpose of lowering the total pre-cure moisture level of the product material.

138. The method of claim 20. wherein the MICP treatment solution contain cement retardants.

139. A CCR site comprising: a CCR stack having a low moisture content area and a high moisture content area; gypsum incorporated into the high moisture content area; and a cement groundwater barrier at a base of the CCR stack.

140. The CCR site of claim 139, wherein the cement groundwater barrier is jet grouted into the gypsum to form a groundwater barrier at the base of the CCR stack.

141. The CCR stie of claim 139, comprising a vertical groundwater barrier positioned above the cement ground w ater barrier.

142. The CCR site of claim 141, wherein the vertical groundwater barrier is a biogeopolymer vertical groundwater barrier.

143. A CCR site comprising: a CCR stack having a low moisture content area and a high moisture content area; a gypsum base at a base of the CCR stack; anda vertical groundwater barrier positioned above the gypsum base.

144. The CCR site of claim 143, wherein the vertical groundwater barrier is a biogeopolymer vertical groundwater barrier.

145. A CCR site comprising;CCR encapsulated throughout at the particulate level, encapsulated in bulk via surrounding hydraulic barriers, or combinations thereof; and additional wastes encapsulated with the CCR.

146. The site of claim 145, wherein the additional wastes include additional CCR wastes from other sites or impoundments.

147. The site of claim 145, wherein the additional wastes include solid waste.

148. The site of claim 145, wherein the additional wastes include liquid effluents from other sites.

149. The site of claim 145, wherein the additional wastes include gaseous wastes to be sequestered.

150. The site of claim 149, wherein the gaseous waste includes as carbon-dioxide.

151. An encapsulated CCR material, the material comprising:CCR; and an encapsulating material encapsulating the CCR.

152. The material of claim 151, wherein the CCR comprises fly ash, bottom ash, boiler slag, flue gas desulfurization (FGD) solids, or combinations thereof.

153. The material of claim 151 , wherein the encapsulated CCR is bound within a sold matrix of the encapsulating material such that mobility of the CCR is inhibited.

154. The material of claim 151, wherein the encapsulating material comprises a geopolymer.

155. The material of claim 154, wherein the geopolymer comprises an inorganic polymer formed by chemical reaction of the CCR with an alkaline activator.

156. The material of claim 155, wherein the geopolymer is formed by mixing the alkaline activator with the CCR to form a non-Portland cement.

157. The material of claim 156, wherein the lime is mixed with the alkaline activator and the CCR.

158. The material of claim 154, wherein the geopolymer is a biogeopolymer.

160. The material of claim 151, wherein the encapsulating material is a biocement.

161. The material of claim 160, wherein the biocement is formed via MICP.

162. The material of claim 151, comprising pollutants in the encapsulated CCR.

163. The material of claim 162, wherein the pollutants comprise carbon dioxide, and wherein the carbon dioxide is sequestered in the encapsulated CCR.

164. The material of claim 151, wherein the encapsulating material comprises gypsum. of the CCR deposit; and mixing the extracted interior portion of the CCR deposit with a second encapsulating material to form a second encapsulated CCR.

165. A construction material made encapsulated CCR, the construction material comprising:CCR; and an encapsulating material encapsulating the CCR.

166. The material of claim 165, wherein the encapsulating material comprises a geopolymer.

167. The material of claim 165, wherein the encapsulating material comprises a biogeopolymer.

168. The material of claim 165, wherein the encapsulating material comprises a gypsum.

169. The material of claim 165, wherein the encapsulating material comprises a biocemnet.

170. The material of claim 169, wherein the biocement is formed via an MICP reaction in the presence of the CCR.

171. The material of claim 165, wherein the encapsulating material is a matrix phase of the of construction material and the CCR is a distributed phase of the construction material and is distributed throughout the matrix phase.

172. The material of claim 165, wherein the encapsulating material is a coating disposed about surfaces of the CCR.

173. A structure comprising encapsulated CCR, the encapsulated CCR including CCR and an encapsulating material encapsulating the CCR.

174. The structure of claim 173. wherein the structure comprises a wall.

175. The structure of claim 173, wherein the structure comprises a barrier.

176. The structure of claim 173, wherein the structure comprises a road.

177. The structure of claim 173, wherein the structure comprises a block or brick.

178. The structure of claim 173, wherein the encapsulating material comprises a geopolymer.

179. The structure of claim 173, wherein the encapsulating material comprises a biogeopolymer.

180. The structure of claim 173, wherein the encapsulating material comprises a gypsum.

181. The structure of claim 173, wherein the encapsulating material comprises a biocemnet.

182. The structure of claim 181. wherein the biocement is formed via an MICP reaction in the presence of the CCR.

183. The structure of claim 173, wherein the encapsulating material is a matrix phase of the of construction material and the CCR is a distributed phase of the construction material and is distributed throughout the matrix phase.

184. The structure of claim 173, wherein the encapsulating material is a coating disposed about surfaces of the CCR.

185. A method of conducting an MICP reaction, the method comprising: providing a first solution containing microbes; providing one or more second solutions containing urea and calcium; and mixing the first solution with the one or more second solutions to form a biocement.

186. The method of claim 185, wherein the microbes comprise bacteria.

187. The method of claim 185, wherein providing the one or more second solutions includes heating the one or more second solutions.

188. The method of claim 186, comprising, after the heating and prior to the mixing, cooling the one or more second solutions.

189. The method of claim 185, wherein the one or more second solutions comprise a one solution of urea and another solution of calium.

190. The method of claim 185, wherein providing the one or more second solutions comprises mixing the calcium with water and, after mixing the calcium, mixing the urea with the water.

191. The method of claim 185, wherein the microbes are in an endospore state.

192. The method of claim 185, wherein the urea and calcium are solid pellets.

193. The method of claim 185, comprising cooling the first solution and the one or more second solutions prior to the mixing.

194. The method of claim 185, comprising incorporating nutrients into the first solution and / or the one or more second solutions, wherein the nutrients are nutrients that the microbes consume.

195. The method of claim 185, comprising adding a cement retardant to the first solution and / or the one or more second solutions.

196. The method of claim 195, wherein the cement retardant comprises sulfates, sulfonates, phosphonates, or combinations thereof.

197. The method of claim 195, wherein the cement retardant comprises gypsum, lignosulfonates, or combinations thereof.

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