Systems and methods for removing ammonia from aqueous streams

Abstract

A system for separating ammonia from an aqueous stream. The system can include a flash vessel configured to receive an aqueous stream and to separate a flashed vapor from liquid in the aqueous stream. An ammonia enrichment unit can be disposed at an upper portion of the flash vessel configured to receive the flashed vapor. The ammonia enrichment unit can include a mass transfer device configured to separate an ammonia-enriched stream at an upper portion of the ammonia enrichment unit from a bottoms liquid having a lower concentration of ammonia than the ammonia-enriched stream.

Description

[0001] SYSTEMS AND METHODS FOR REMOVING AMMONIA FROM AQUEOUS STREAMS

[0002] PRIORITY DATA

[0003] This application claims the benefit of United States Provisional Patent Application Serial No. 63 / 519,195, filed August 11, 2023, which is incorporated by reference in its entirety.

[0004] BACKGROUND

[0005] The present disclosure is directed to treatment of aqueous streams containing ammonia. Ammonia is a commonly-produced chemical with a variety of uses in industry. Ammonia can be used as a refrigerant, in dyes, in chemical processes, and in the manufacture of fertilizer, among many other applications. However, ammonia is also a common contaminant in municipal, industrial, and agricultural wastewater. This ammonia can be damaging to the environment and to human health. Therefore, removing ammonia can be a major part of wastewater treatment. Ammonia can be found in sewage due to the decomposition of nitrogen-containing compounds from biological material. Sewage also contains many pathogenic microorganisms that can be removed during treatment of the sewage. A combination of ammonia and pathogenic microorganisms can also be found in a variety of other types of municipal, industrial, and agricultural wastewater.

[0006] SUMMARY

[0007] The present disclosure describes systems and methods for removing ammonia from an aqueous stream. In one example, a system for removing ammonia from an aqueous stream includes a flash vessel configured to receive an aqueous stream and to separate a flashed vapor from liquid in the aqueous stream. The system also includes an ammonia enrichment unit disposed at an upper portion of the flash vessel configured to receive the flashed vapor. The ammonia enrichment unit includes a mass transfer device configured to separate an ammonia-enriched stream at an upper portion of the ammonia enrichment unit from a bottoms liquid having a lower concentration of ammonia than the ammonia-enriched stream.

[0008] In some examples, the systems for removing ammonia from an aqueous stream can be integrated into a system for treating wastewater, and the aqueous stream can be a biological wastewater stream. These systems can be operable to treat and condition a biological wastewater stream (such as waste activated sludge or WAS) with up to or greater than about a 4% solids to 96% water ratio. With the biological wastewater stream so conditioned, it is ready for further treatment either through a digester and / or dewatering technology. The systems and methods set forth herein can enhance both a digestion and a dewatering process. For an application using a digester, the systems and methods can improve the processing rate thereby allowing the digester to process larger flows within a smaller sized digester. As another advantage, when used in conjunction with an anaerobic digester, an additional up to 25% or more increase in the generation of bio-gas (methane) is expected. Furthermore, when used in conjunction with cither an aerobic or anaerobic digester, an additional 25% or more reduction in the generation of solids is expected. For dewatering, the systems and methods can improve the dewaterability of the biological wastewater stream to reduce the overall volume of the material to be disposed. It is estimated that the benefits of improved digestion and dewatering outweigh the additional operating and energy costs associated with the systems and methods set forth herein.

[0009] BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Additional features and advantages of invention embodiments will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention; and, wherein:

[0011] FIG. 1 is a schematic view of an example system for removing ammonia from an aqueous stream in accordance with an exemplary embodiment;

[0012] FIG. 2 is a schematic view of another example system for removing ammonia from an aqueous stream in accordance with an exemplary embodiment;

[0013] FIG. 3 is a schematic view of another example system for removing ammonia from an aqueous stream in accordance with yet another exemplary embodiment;

[0014] FIG. 4 is a schematic view of an additional example system for removing ammonia from an aqueous stream in accordance with another exemplary embodiment;

[0015] FIG. 5 is a schematic view of another example system for removing ammonia from an aqueous stream in accordance with another exemplary embodiment; FIG. 6 is a schematic view of a system for treating biologically contaminated water, which incorporates a system for removing ammonia, in accordance with an exemplary embodiment;

[0016] FIG. 7 is a schematic view of another system for treating biologically contaminated water in accordance with an exemplary embodiment; and

[0017] FIG. 8 is a schematic view of another system for treating biologically contaminated water in accordance with an exemplary embodiment.

[0018] Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.

[0019] DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0020] Before invention embodiments are described, it is to be understood that this disclosure is not limited to the particular structures, process steps, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular examples or embodiments only and is not intended to be limiting. The same reference numerals in different drawings represent the same element. Numbers provided in flow charts and processes are provided for clarity in illustrating steps and operations and do not necessarily indicate a particular order or sequence.

[0021] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of compositions, dosage forms, treatments, etc., to provide a thorough understanding of various invention embodiments. One skilled in the relevant art will recognize, however, that such detailed embodiments do not limit the overall inventive concepts articulated herein, but are merely representative thereof.

[0022] It should be noted that as used herein, the singular forms “a,” “an,” and, “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a stream” includes reference to one or more of such streams, and reference to “the organism” includes reference to one or more of such organisms. In this disclosure, “comprises,” “comprising,” “containing” and “having” and the like can have the meaning ascribed to them in U.S. Patent law and can mean “includes,” “including,” and the like, and are generally interpreted to be open ended terms. The terms “consisting of’ or “consists of’ are closed terms, and include only the components, structures, steps, or the like specifically listed in conjunction with such terms, as well as that which is in accordance with U.S. Patent law. “Consisting essentially of” or “consists essentially of” have the meaning generally ascribed to them by U.S. Patent law. In particular, such terms are generally closed terms, with the exception of allowing inclusion of additional items, materials, components, steps, or elements, that do not materially affect the basic and novel characteristics or function of the itcm(s) used in connection therewith. For example, trace elements present in a composition, but not affecting the compositions nature or characteristics would be permissible if present under the “consisting essentially of” language, even though not expressly recited in a list of items following such terminology. When using an open ended term, like “comprising” or “including,” in the written description it is understood that direct support should be afforded also to “consisting essentially of’ language as well as “consisting of” language as if stated explicitly and vice versa.

[0023] The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that any terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Similarly, if a method is described herein as comprising a series of steps, the order of such steps as presented herein is not necessarily the only order in which such steps may be performed, and certain of the stated steps may possibly be omitted and / or certain other steps not described herein may possibly be added to the method.

[0024] As used herein, comparative terms such as “increased,” “decreased,” “better,” “worse,” “higher,” “lower,” “enhanced,” “maximized,” “minimized,” and the like refer to a property of a device, component, composition, or activity that is measurably different from other devices, components, compositions or activities that are in a surrounding or adjacent area, that are similarly situated, that are in a single device or composition or in multiple comparable devices or compositions, that are in a group or class, that are in multiple groups or classes, or as compared to the known state of the art.

[0025] As used herein, “remove” can refer to complete removal or partial removal of a particular element. In particular, to “remove ammonia from an aqueous stream” can refer to removing a portion of the ammonia in the aqueous stream, as complete removal of all ammonia present in the stream may not be practical. Similarly, to “separate” can refer to complete separation or partial separation.

[0026] As used herein, the term “microorganism” refers to any organism that is too small to be individually viewed with a naked eye. Some microorganism may include a cell wall or other membrane, including a cellulosic or lipidic structure that houses internal organelles and components, such as nucleic acids, etc., and may further contain water or other fluids. Examples of such microorganisms can include without limitation, algae, bacteria, spores, virus, protozoa, etc. As used herein the term “pathogen” refers to any disease promoting microorganism.

[0027] As used herein, the term “biological wastewater,” “biologically contaminated wastewater,” and “biologically contaminated water” can be used interchangeably and these as well as like terms refer to a composition or solution (e.g. an aqueous solution) that contains a measurable amount of at least one microorganism.

[0028] The term “coupled,” as used herein, is defined as directly or indirectly connected in a chemical, mechanical, electrical or nonelectrical manner. Objects described herein as being “adjacent to” each other may be in physical contact with each other, in close proximity to each other, or in the same general region or area as each other, as appropriate for the context in which the phrase is used. “Directly coupled” objects or elements are in physical contact with one another.

[0029] Occurrences of the phrase “in one embodiment,” or “in one aspect,” herein do not necessarily all refer to the same embodiment or aspect.

[0030] As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is cither completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, a composition that is “substantially free of” particles would either completely lack particles, or so nearly completely lack particles that the effect would be the same as if it completely lacked particles. In other words, a composition that is “substantially free of’ an ingredient or element may still actually contain such item as long as there is no measurable effect thereof.

[0031] As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint. Unless otherwise stated, use of the term “about” in accordance with a specific number or numerical range should also be understood to provide support for such numerical terms or range without the term “about”. For example, for the sake of convenience and brevity, a numerical range of “about 50 angstroms to about 80 angstroms” should also be understood to provide support for the range of “50 angstroms to 80 angstroms.” Furthermore, it is to be understood that in this specification support for actual numerical values is provided even when the term “about” is used therewith. For example, the recitation of “about” 30 should be construed as not only providing support for values a little above and a little below 30, but also for the actual numerical value of 30 as well.

[0032] As used herein, a plurality of items, structural elements, compositional elements, and / or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.

[0033] Concentrations, amounts, levels and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges or decimal units encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “about 1 to about 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc., as well as 1, 2, 3, 4, and 5, individually. This same principle applies to ranges reciting only one numerical value as a minimum or a maximum. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described.

[0034] Reference throughout this specification to “an example” means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment. Thus, appearances of the phrases “in an example” in various places throughout this specification are not necessarily all referring to the same embodiment.

[0035] Description of Embodiments

[0036] The present disclosure describes systems and methods for separating ammonia from an aqueous stream. These systems and methods can be used with any type of aqueous stream that contains ammonia. In certain examples, however, the aqueous stream can include contaminated water that has been treated or which will be treated by a biological treatment process.

[0037] Contaminated water having high levels of organic material measured in terms of Biological Oxygen Demand (BOD) is often treated using a biological treatment process to remove organic material from the contaminated water. This process creates an environment favorable for exponential growth of biological organisms (primarily bacteria) that utilize the organic waste in the contaminated water for cell reproduction. The result of a biological treatment process is that the organic material is removed from the water (BOD levels in the water decrease) and a large population of biological organisms are created. One type of biomass that is created is often referred to as activated sludge. The excess biomass that is produced is referred to as waste activated sludge (WAS).

[0038] One problem associated with such a biological treatment process concerns the final disposal of the solids in the contaminated waste. WAS, or the biomass that is no longer needed within the biological treatment process is generally disposed either as a reusable product (as a fertilizer) or at a landfill. However, WAS is not a simple waste product to dispose. This is because WAS contains pathogens (disease causing bacteria), and it readily retains water. Therefore, it is difficult to reduce the overall volume of the WAS using traditional water separation technologies. The disposal of WAS is an abundant problem as nearly every municipal wastewater treatment plant in the United States creates WAS daily (approximately 16,000 locations).

[0039] In many locations around the USA, WAS is dewatered to approximately 20% solid content and 80% water content. Then it is shipped to a landfill for disposal. Larger municipal plants will often employ digesters to process the WAS which creates some natural gas for energy production, slightly reduces final disposal volumes, and most importantly, destroys the pathogens rendering the WAS safer for reuse applications. However, even when digesters arc employed, dewatering the WAS does not improve. That is, there still remains about a 20% solids to 80% water ratio.

[0040] If a standard sized wastewater treatment plant (just 1 of the 16,000 systems in the USA) produces 3,000 Ibs. / day of dry WAS, this means that approximately 15,000 Ibs. / day of the dewatered WAS will be shipped off for reuse or disposal. Disposal costs for WAS at landfill sites around the US is rising and is regularly above $50 / ton. This presents a significant cost for wastewater treatment plants around the country.

[0041] The presence of ammonia in wastewater can present additional challenges. Ammonia can be harmful to the biological organisms used in biological water treatment processes. Thus, ammonia in wastewater can decrease the efficiency of using biological treatment processes to remove organic material in the wastewater. Additionally, ammonia that remains in WAS can be considered a pollutant and can make it more difficult to dispose of.

[0042] Accordingly, the systems and methods for separating ammonia can be particularly useful in processes for wastewater treatment. The present disclosure describes certain thermal systems that use heat to break down (lyse) organism (e.g. bacterial) cells in biologically contaminated water, such as waste activated sludge (WAS). For example, by increasing the temperature of a liquid above 100°C, bacterial cell walls will begin to weaken and rupture. Additionally, rapidly changing pressures will cause a bacterial cell to expand and / or contract based on the external pressures placed on the cell to further weaken and break down cell walls. The systems and methods can utilize one or both techniques to lyse the cells in the contaminated water, thereby releasing water that had been trapped inside the cell. Additionally, the increased temperature and rapid pressure changes serves to denature larger chain polymers and complex organic molecules in the contaminated water.

[0043] As will be described in more detail below, the present disclosure can utilize the addition of steam and pressure to heat the contaminated water in the system above a boiling temperature at standard atmospheric pressure. Then, using a pump, the system can cycle the boiling contaminated water across an orifice. This can continually raise and lower the liquid pressure thereby raising and lowering the pressure against organism cell walls in the contaminated water. Furthermore, the vapors created from active boiling in the system can be collected and compressed through a blower and then can be reinjected into the liquid stream. This can help recover the latent heat of evaporation from the boiling solution, increasing efficiency.

[0044] A process for removing ammonia from the contaminated water stream can be incorporated with this treatment process. In some examples, the contaminated water can be heated and pumped to a high pressure and then released into a flash vessel. The sudden change in pressure at high temperature can lyse cells as explained above. The flash vessel can separate steam in a vapor phase from liquid contaminated water. The vapor phase in the flash vessel can contain a relatively larger concentration of ammonia than the liquid phase. The ammonia can then be further concentrated using an ammonia enrichment unit positioned at an upper portion of the flash vessel. In some examples, the ammonia enrichment unit can operate like a small distillation column with packing material, trays, or other mass transfer devices for separating ammonia from water. An ammonia-enriched stream can be collected at the top of the ammonia enrichment unit, while liquid water can drip back down into the flash vessel. Thus, a significant amount of ammonia can be removed from the contaminated water stream while the stream is also being treated by lysing cells.

[0045] The system can accomplish cell lysis and denaturing of the contaminated water, while also removing ammonia from the water, while also being mindful to conserve energy. Outgoing contaminated water can be sent through a heat exchanger that can recover heat energy by transferring it back to the incoming contaminated water that is just entering. Additionally, as stated earlier, liberated water in the form of steam can be compressed and reinjected back into the incoming contaminated water to recover the latent heat of vaporization. In all, it is estimated that the system will be able to create complete cell destruction of the contaminated water stream at an energy demand of approximately 500 KWH / ton dry contaminated water solids. At a standard energy cost of 0.08 / KWH, this is a cost of $40 / ton dry contaminated water solids. In comparison, an estimated disposal cost of $50 / wet ton contaminated water solids (which could be 5 times the volume of dry tons) is a common rate for landfill disposal in the country. Comparing these two values, utilizing the systems and methods set forth herein can result in a significant reduction of disposal costs. When considering that the pathogens will be also be killed in the contaminated water, the possibility of reuse increases instead of only considering the product for landfill disposal.

[0046] As mentioned above, the system can be used in conjunction with a digester. The system can improve the processing rate thereby allowing the digester to process larger flows within a smaller sized digester. In some examples, the system can be implemented as a pretreatment in front of a digester and can manage the flow of a biologically contaminated wastewater stream to the digester. Because the system removes ammonia from the wastewater, the wastewater can be more suitable for treatment in the digester using organisms to which ammonia would be toxic. In some examples, the system can be configured as a slip stream circulating from the back of a digester to the front. In some examples, a digester can be an anaerobic digester.

[0047] Several example embodiments of the system and methods are described below. FIG. 1 shows one example system 100 for removing ammonia from an aqueous stream. This example includes a flash vessel 103 that is configured to receive an aqueous stream 106 and to separate the aqueous stream into a flashed vapor and a liquid within the flash vessel. The aqueous stream can undergo a reduction in pressure when entering the flash vessel or prior to entering the flash vessel, and the reduction in pressure can trigger partial evaporation of the aqueous stream. The evaporated steam can fill an upper part of the flash vessel, and the unevaporated liquid can collect in a lower part of the lash vessel. The vapor phase and the liquid phase can include water and a variety of other compounds and materials besides water, such as ammonia. As used herein, “steam” can refer to the vapor phase separated from the liquid phase in the flash vessel, which can be primarily water vapor but can also include ammonia and other compounds. This vapor phase can also be referred to as “flashed vapor.” The term “steam” can also be used to describe pure water vapor from other sources, such as make-up steam that can be added to the system for heating or other purposes. The system 100 in FIG. 1 also includes an ammonia enrichment unit 130 at an upper portion of the flash vessel 103. The ammonia enrichment unit is configured to receive flashed vapor from the flash vessel. In this particular example, the ammonia enrichment unit is a column that extends from a roof of the flash vessel, with an opening from the flash vessel into the ammonia enrichment unit. The ammonia enrichment unit includes a mass transfer device 131 configured to separate an ammonia-enriched stream 133 at an upper portion of the ammonia enrichment unit from a bottoms liquid having a lower concentration of ammonia than the ammonia-enriched stream. The bottoms liquid is not shown in the figure, but the bottoms liquid can run freely back down from the ammonia enrichment unit into the flash vessel. The liquid in the flash vessel exits through a liquid line 104.

[0048] In some examples, the ammonia enrichment unit can be a separate unit from the flash vessel, while in other examples the ammonia enrichment unit can be integrated into the flash vessel. The ammonia enrichment unit can be a portion of the flash vessel at an upper portion of the flash vessel that includes appropriate mass transfer devices to concentrate ammonia into an ammonia-enriched stream. In other examples, the ammonia enrichment unit can extend from the flash vessel. The ammonia enrichment unit can extend from the top surface, or roof, of the flash drum, as shown in FIG. 1. In other examples, the ammonia enrichment unit can extend from a sidewall of the flash vessel. The upper portion of the flash vessel can be defined as any portion of the vessel that is above the liquid collected at the bottom of the vessel. Thus, when the ammonia enrichment unit is located at an upper portion of the flash vessel, the vapor can flow into the ammonia enrichment unit but the liquid in the bottom of the flash vessel does not flow into the ammonia enrichment unit.

[0049] The ammonia enrichment unit can include an opening leading to an upper portion of the flash vessel, which can allow vapor to flow from the flash vessel into the ammonia enrichment unit. The opening can also allow liquid to flow from the ammonia enrichment unit back into the flash vessel. In other examples, the ammonia enrichment unit can be a separate vessel from the flash vessel, and the ammonia enrichment unit can be connected to the flash vessel by a pipe or pipes. In one such example, a vapor pipe can carry vapor from the flash vessel to the ammonia enrichment unit, and a liquid pipe can carry bottoms liquid from the ammonia enrichment unit back to the flash vessel. Alternatively, a liquid pipe can carry the bottoms liquid from the ammonia enrichment vessel and mix the bottoms liquid back into another liquid stream somewhere else in the system, such as a recycle stream of the liquid collected int the flash vessel.

[0050] The flash vessel can have any size suitable for the flow rate of the aqueous stream. In various examples, the flash vessel can have a diameter from about 0.5 m to about 10 m, or from about 1 m to about 8 m, or from about 1 m to about 5 m. The flash vessel can be oriented vertically or horizontally. The height (for a vertical flash vessel) or length (for a horizontal flash vessel) can be from about 1 m to about 30 m in some examples, or from about 2 m to about 20 m, or from about 3 m to about 10 m.

[0051] In certain examples, the ammonia enrichment unit can include a column. The column can be formed as a housing that has a height taller than a diameter or width of the column. A mass transfer device or multiple such devices can be contained within the housing to separate the ammonia-enriched stream from the bottoms liquid. The column can extend from an upper portion of the flash vessel as described above. In some examples, the column can be formed as an integral part of the flash vessel housing, while in other examples the column can be a separate piece that is attached onto the flash vessel. In further examples, the column can have a diameter that is less than a diameter of the flash vessel. For example, the diameter of the column can be from about 5% to about 75% of the diameter of the flash vessel, or from about 10% to about 50% of the diameter of the flash vessel, or from about 10% to about 30% of the diameter of the flash vessel. In certain examples, the column can have a diameter from about 0.1 m to about 3 m, or from about 0.2 m to about 2 m, or from about 0.3 m to about 1 m. The column can have a height sufficient to accommodate the mass transfer devices within the ammonia enrichment unit. In some examples, the height can be from about 0.5 m to about 10 m.

[0052] The ammonia enrichment unit can include a mass transfer device configured to separate the ammonia-enriched stream at an upper portion of the ammonia enrichment unit from a bottoms liquid having a lower concentration of ammonia than the ammonia-enriched stream. Examples of mass transfer devices can include random packing, structured packing, distillation column trays, liquid distributors, reflux pumps, reflux condensers, and others. The mass transfer device can be configured to perform multiple separation stages in which ammonia is separated from water. In some examples, the number of separation stages can be from 2 to 10. In some examples, the mass transfer device can include a packing material, such as random packing, structured packing, or a combination thereof. FIG. 2 shows an example system 100 that includes random packing 137. The random packing material can be a material with a high surface area per volume. High surface area can provide for a large amount of liquid-vapor interface area, which can allow ammonia to leave the liquid phase and concentrate in the vapor phase while liquid flows downward through the packing material. A variety of random packing materials can be used, such as rings, spheres, and engineered random packing materials. Random packing materials can be made up of small individual pieces that are randomly filled in the interior of the ammonia enrichment unit 130. The example shown in FIG. 2 also includes a liquid distributor 132, which is another type of mass transfer device that can be included in the ammonia enrichment unit. The liquid distributor can distribute liquid droplets more evenly when the droplets fall into the packing material. The liquid distributor can include a variety of features for distributing the liquid, such as tubes, perforations, plates, nozzles, sprayers, and so on. This example system also includes an ammonia-enriched stream 133, a flash vessel 103, an aqueous stream 106, and a liquid line 104.

[0053] In other examples, a structured packing material can be used in the ammonia enrichment unit. The structured packing material can be a larger, stationary piece that is designed to have a large surface area and to direct liquid to spread out over a large surface area is the liquid flows through the structured packing material. In some examples, the structured packing material can include complex channels for the liquid to flow through. The structured packing material can be sized and shaped to fit within the ammonia enrichment unit. Some types of structured packing material that can be used include corrugated structured packing, honeycomb structured packing, and others.

[0054] The mass transfer device can also include distillation column trays. These can operate similarly to a distillation column, with a liquid aqueous phase flowing downward on the trays, and a vapor phase with higher ammonia concentration bubbling upward past the trays. The trays can include features for increase contact between the vapor phase and the liquid phase, such as perforations, bubble caps, weirs, valves, baffles, and others. The number of trays can be selected to provide a desired level of separation. In some examples, the number of trays can be from 1 to 10, or from 2 to 6, or from 2 to 5, or from 2 to 4 or more. FIG. 3 shows another example system 100 that includes distillation column trays 138 in the ammonia enrichment unit 130. When this system is in operation, a liquid phase can flow downward from tray to tray while vapor rises to flow out an outlet at the top of the unit as the ammonia-enriched stream 133. The liquid can flow from the bottom tray back into the flash vessel 103 so that the liquid from the ammonia enrichment unit mixes with the liquid separated from the aqueous stream 106 in the flash vessel. This liquid flows out of the flash vessel through a liquid line 104.

[0055] The mass transfer device can also include a reflux line. The reflux line can recycle a portion of the ammonia-enriched stream back to the ammonia enrichment unit. In certain examples, the reflux line can recycle a portion of the ammonia-enriched stream in liquid form. This liquid reflux stream can be introduced back into the ammonia enrichment unit near the top of the unit, so that the liquid can flow back down through any packing material, distillation trays, or other devices inside the unit. This can provide additional contact time between the liquid phase and the vapor phase to allow more separation of the ammonia from the aqueous liquid phase.

[0056] In certain examples, the reflux stream can be converted from a vapor to a liquid using a reflux condenser. The reflux condenser can be connected to the reflux line to condense the portion of the ammonia-enriched stream that is to be recycled back to the ammonia enrichment unit. FIG. 4 shows an example system 100 that includes a reflux condenser 140. In this example, an ammonia-enriched stream 133 flows out of the ammonia enrichment unit 130. The ammonia-enriched stream then passes through the reflux condenser to condense at least a portion of the stream into liquid. The condensed stream is then split into a reflux line 142 and a product stream 144. The reflux line leads back to an upper portion of the ammonia enrichment unit. The liquid reflux can flow down through the mass transfer device 131, such as packing materials, trays, or others. As in the previous examples, this system also includes a flash vessel 103, an aqueous stream 106, and a liquid line 104 at the bottom of the flash vessel.

[0057] The separation of ammonia can be affected by the design of the ammonia enrichment unit, as described above, and by several operational parameters. These parameters can include the flow rate of the aqueous stream into the flash vessel, the fraction of the aqueous stream that evaporates in the flash vessel, the flow rate of the ammonia-enriched stream, the flow rate of any reflux streams, the temperatures at various locations in the ammonia enrichment unit, pressure in the flash vessel, and others. The temperatures at the top and bottom of the ammonia enrichment unit can be close to the boiling temperature of water, which can depend on the pressure within the ammonia enrichment unit.

[0058] In some examples, the temperature at the top and / or at the bottom of the ammonia enrichment unit can be from about 90 °C to about 200 °C, or from about 100 °C to about 180 °C, or from about 100 °C to about 150 °C, or from about 120 °C to about 180 °C, or from about 100 °C to about 120 °C.

[0059] In certain examples, the temperature at the top of the ammonia enrichment unit can be lower than the temperature at the bottom of the ammonia enrichment unit. The temperature difference between the top and bottom can be from about 0.01 °C to about 20 °C, or from about 0.1 °C to about 10 °C, or from about 0.1 °C to about 5 °C, or from about 5 °C to about 10 °C, in some examples.

[0060] The pressure in the ammonia enrichment unit can be from about 0 PS1G to about 100 PSIG, or from about 0 PSIG to about 50 PSIG, or from about 0 PSIG to about 30 PSIG, or from about 15 PSIG to about 50 PSIG, or from about 15 PSIG to about 30 PSIG, in some examples.

[0061] The concentration of ammonia in the ammonia-enriched stream can depend on the various parameters described above. The initial concentration of ammonia in the aqueous stream can also affect the final concentration in the ammonia-enriched stream. A variety of types of aqueous streams can be treated using the systems described herein, hi various example, the initial concentration of ammonia in the aqueous stream can be from about 20 ppm to about 200,000 ppm, or from about 20 ppm to about 50,000 ppm, or from about 20 pm to about 10,000 ppm, or from about 20 ppm to about 5,000 ppm, or from about 20 ppm to about 1,000 ppm, or from about 20 ppm to about 500 ppm, or from about 500 ppm to about 1,000 ppm, or from about 1,000 ppm to about 5,000 ppm, or from about 5,000 ppm to about 10,000 ppm. The concentration of ammonia in the ammonia-enriched stream can be higher than the initial concentration of ammonia in the aqueous stream. In some examples, the ammonia concentration in the ammonia-enriched stream can be from about 5 wt% (10,000 ppm) to about 75 wt%, or from about 10 wt% to about 50 wt%, or from about 20 wt% to about 50 wt%, or from about 25 wt% to about 50 wt%, or from about 30 wt% to about 50 wt%, or greater than 25 wt%, or greater than 30 wt%, or greater than 50 wt%.

[0062] The ammonia-enriched stream can flow out of an upper portion of the ammonia enrichment unit. The ammonia enriched stream can then be disposed of, used as-is, or further treated. In some examples, the ammonia can be used or sold as a product as-is. The ammonia can also be further purified and then used or sold. In other examples, the ammonia can be converted to another product, such as an ammonium salt. Additional processing of the ammonia, such as purification or conversion to another product, can be performed by an ammonia processing unit. The ammonia processing unit can be connected to the ammonia- enriched stream and configured to receive the ammonia-enriched stream.

[0063] In some examples, the ammonia processing unit can be configured to convert ammonia in the ammonia-enriched stream into an ammonium salt. An acid stream can be configured to supply an acid to the ammonia processing unit to react with the ammonia to form the ammonium salt. The ammonium salt can then be sold or used as a product. Acids that can be used to react with the ammonia include sulfuric acid, nitric acid, hydrochloric acid, and others. The ammonium salt formed from the reaction can include ammonium sulfate, ammonium nitrate, ammonium chloride, or others.

[0064] FIG. 5 shows another example system 100 that includes an ammonia processing unit 134. The ammonia processing unit is configured to receive the ammonia-enriched stream 133 from the ammonia enrichment unit 130. An acid stream 135 also flows to the ammonia processing unit so that the acid can react with the ammonia in the ammonia processing unit. An ammonium salt-containing stream 136 flows out of the ammonia processing unit as a product stream. This system also includes a mass transfer device 131 in the ammonia enrichment unit, a flash vessel 103, an aqueous stream 106, and a liquid line 104 as in the other examples.

[0065] The systems described herein can also include a steam outlet in the flash vessel, where a portion of the steam in the flash vessel can flow out through the steam outlet instead of being concentrated by the ammonia enrichment unit. In other words, a first portion of the vapor in the flash vessel can flow out through the steam outlet while a second portion can flow up into the ammonia enrichment unit. The steam outlet can be located below the ammonia enrichment unit. The steam within the flash vessel can have a lower ammonia concentration compared to the ammonia-enriched stream at the top of the ammonia enrichment unit. Therefore, the portion of the steam that is released through the steam outlet can have the lower ammonia concentration. In certain examples, the steam outlet can include a cover or shield to prevent liquid from flowing out with the steam. In some examples, the steam from the steam outlet can be compressed and reinjected into another stream in the system to increase the temperature and / or pressure of the stream. The steam can be injected using a steam sparger in some examples. In certain examples, the steam can be injected by a steam sparger into the aqueous stream before the aqueous stream enters the flash vessel.

[0066] In further examples, a mist separator, or demister, can be connected to the steam outlet. The mist separator can extract liquid from the steam. The liquid extracted by the mist separator can then be recycle into the flash vessel or added to another stream in the system.

[0067] The systems described herein can be configured to treat biologically contaminated water. Accordingly, in some examples the aqueous stream can comprise biologically contaminated water. The systems can also include additional equipment configured to treat biologically contaminated water. Several example water treatment systems are described below, which can each incorporate the systems for separating ammonia described herein. It is noted that any of the features of the systems for separating ammonia can be included in the water treatment systems.

[0068] FIG. 6 is a schematic block diagram illustrating an embodiment of a system 200 to provide water treatment services. The system is provided that is operable to treat contaminated water by lysing cell walls to release water and fluid within the cells, thus making the water easier to filter and therefore minimizing the solids to dispose. The system is further operable to destroy dangerous pathogens by temperature and residence time in accordance with EPA specifications, further contributing to making the solids easier to dispose. Additionally, the system can separate ammonia from the contaminated water as described above.

[0069] The system 200 can include a biologically contaminated water feed stream 201 entering the system and a treated water stream 119 leaving the system. The biologically contaminated water feed stream can come from any upstream equipment or processes that produces contaminated water, such as but not limited to, waste activated sludge digesters (e.g. aerobic or anaerobic digesters), filters, centrifuges, hospitals, pharmaceutical manufacturing, food plants, etc. Furthermore, the contaminated water stream can contain differing concentration ranges of solids (e.g. 0% to 30%). The treated water leaving the system can be sent for further treating or solids separation, which is not shown here. The solids content and volume of the treated water can be the same or slightly more than the contaminated feed steam.

[0070] The system 200 takes the biologically contaminated water stream 201 and preheats it in a preheater exchanger 101 using the hot treated water stream 118 as a heat source. This recovers heat from the system and makes the system more efficient, thus helping to reduce energy costs associated with the system. The preheated biologically contaminated water stream 102 then joins a circulation stream (aqueous stream) 106.

[0071] The circulation of the contaminated water in the circulation stream 106 will now be described beginning with a flash vessel 103 shown in FIG. 6. The liquid in the bottom of the flash vessel exits the flash vessel to the circulation pump 105 suction via a line 104.

[0072] The circulation pump 105 is operable to raise the pressure of the contaminated water in the circulation stream 106. For example, the circulation pump can increase the pressure of the circulation stream from about 0 PSIG to about 50 PSIG. The flow rate through the circulation pump can be, for example, from about 5 to about 400 times the flow rate of the biologically contaminated water feed 201. The circulation pump discharges into the circulation stream. The main circulation stream then splits into a part 106A of the main circulation stream and into a hot treated water stream 118 that then enters the heat exchanger 101 and exits the system 200 as the treated water stream 119, as described above.

[0073] The circulation pump 105 can be a centrifugal, positive displacement, diaphragm, or other type of pump. The preheated contaminated water feed 102 joins with part 106A of the main circulation stream 106 to form pail 106B of the main circulation stream. Compressed steam 114 from a blower 113 can be injected via a steam sparger 115 into the main circulation stream at part 106B to heat the main circulation stream at part 106C.

[0074] Makeup steam 116 can be introduced to the main circulation 106C via a steam sparger 117 to provide make up heat to the circulation stream 106 at part 106D. The makeup steam can be provided from an external source to add heat energy to the system 200. The steam spargers 115 and 117 can be a perforated pipe, eductor, or other device that can mix the steam and liquid in the pipe. The heated part 106D of the main circulation stream can then be flashed through a pressure drop device 107 to form steam in part 106E of the circulation stream which can then be introduced to the flash sparger 108 in the flash vessel 103 where the steam and liquid are separated. The pressure drop device can be an orifice plate, valve, gate, door, constriction (e.g. a venturi), filter, junction, bend, or other device or configuration that creates a pressure drop. The pressure drop device is where much of the cell lysing can occur due to the high temperatures and change from high to low pressure. In some embodiments, the drop in pressure can be from about 100 PSIG to 50PSIG. In some other embodiments, the drop can be from about 150 PSIG to about 15 PSIG. In some embodiments, the pressure drop can be from a higher pressure to a lower pressure can be from about a 10% drop in pressure to about a 90% drop in pressure. In other embodiments, the drop can be about 20%, 30%, 40%, 50%, 60%, 70%, 80%, or other percentage drops in between as needed in order to achieve a specific result. Such pressure drops can significantly contribute to the lysing of microcellular organisms as discussed herein. Temperatures in the main circulation stream can range from 150 to 300 degrees Fahrenheit which is sufficient to destroy all pathogens that were introduced into the system via the biologically contamination water stream 201.

[0075] At the top of the of flash vessel 103, a smaller diameter ammonia enrichment unit 130 received vapor from the flash vessel. The ammonia enrichment unit includes mass transfer devices, including packing 137 and a liquid distribution device 132. Other types of mass transfer devices such as trays could be used. In other examples, the mass transfer system can also include the return of some of the ammonia-enriched stream 133 back to the ammonia enrichment unit as reflux. As the vapors pass through the ammonia enrichment unit 130 the concentration of ammonia will increase. This ammonia-enriched stream is directed to an ammonia processing unit 134 which can recover the ammonia in a usable form 136. This can involve the addition of an acid stream 135 such as sulfuric or nitric acid.

[0076] To increase efficiency, steam from the flash vessel 103 can be captured from a steam outlet located beneath the ammonia-enrichment unit. This portion of the steam can be directed through line 109 to enter a mist eliminator 110 where any mist is separated from the steam. Tiquid recovered from the mist eliminator is directed through line 111 to be reintroduced to the flash vessel. The dry steam from the mist eliminator can be directed through line 112 to be compressed in the blower 113. For example, the pressure on the outlet of the blower can be between 5 and 30 PSIG. The blower can be a rotary lobe, fan, centrifugal, or other type of compressor. The compressed steam from the blower is directed through line 114 to be reintroduced to the main circulation stream 106 at part 106B via the steam sparger 115, as mentioned above. This process of steam capture and reintroduction helps to recover latent heat in the system 200 to increase its overall efficiency.

[0077] As mentioned above, hot treated water 118 from the main circulation 106 is separated from the circulation line 106 and is directed to the preheater 101 where it heats the biologically contaminated water feed 119 while cooling the treated water outlet stream 119. The preheater 101 can be a plate and frame, spiral, shell and tube, or other type of heat exchanger.

[0078] FIG. 7 is a schematic block diagram illustrating another embodiment of a system 200 to provide water treatment services. The system shown in FIG. 7 is similar to FIG. 6 and like parts are labeled using like identifiers. The system is operable to treat contaminated water by lysing cell walls, thus making the water easier to filter and therefore minimizing the solids to dispose. The system is further operable to destroy dangerous pathogens by temperature and residence time in accordance with EPA specifications, further contributing to making the solids easier to dispose.

[0079] The system 200 can include a biologically contaminated water feed stream 201 entering the system and a treated water stream 119 leaving the system. The biologically contaminated water feed stream can come from any upstream equipment or processes that produces contaminated water such as but not limited to waste activated sludge digesters, filters, centrifuges, hospitals, pharmaceutical manufacturing, food plants, etc. Furthermore, the contaminated water stream can contain from 0% to 30% solids. The treated water leaving the system can be sent for further treating or solids separation, which is not shown here. The solids content and volume of the treated water can be the same or slightly more than the contaminated feed steam.

[0080] The system 200 takes the biologically contaminated water stream 201 and preheats it in a preheater exchanger 101 using the hot treated water stream 118 as a heat source. This recovers heat from the system and makes the system more efficient, thus helping to reduce energy costs associated with the system. The preheated biologically contaminated water stream 102 then joins a circulation stream 106. The circulation of the contaminated water in the circulation stream 106 will now be described beginning with a flash vessel 103 shown in FIG. 7. The liquid in the bottom of the flash vessel exits the flash vessel to the circulation pump 105 suction via line 104. Unlike the example system shown in FIG. 6, compressed steam from the blower 113 is fed through line 214 to be injected via a steam sparger 215A into the line 104 of the main circulation stream 106 to further heat the main circulation stream 106 in part 104A. Part 104A of the main circulation stream then goes to the circulation pump 105.

[0081] The circulation pump 105 is operable to raise the pressure of the contaminated water in the circulation stream 106. For example, the circulation pump can increase the pressure of the circulation stream by 15 to 100 PSIG. The flow rate through the circulation pump can be, for example, from 5 to 400 times the flow rate of the biologically contaminated water feed 201. The circulation pump discharges into the circulation stream. The main circulation then splits into a part 106 A of the main circulation stream and into a hot treated water stream 118 that then enters the heat exchanger 101 and exits the system 200 as the treated water stream 119, as described above.

[0082] The circulation pump 105 can be a centrifugal positive displacement, diaphragm, or other type of pump. The preheated contaminated water feed 102 joins with part 106A of the main circulation stream 106 to form part 106B of the main circulation stream. Makeup steam 116 can be introduced to the main circulation 106B via a steam sparger 117 to provide make up heat the circulation stream at part 106C. The makeup steam can be provided from an external source to add heat energy to the system 200.

[0083] The steam spargers 215A and 117 can be a perforated pipe, eductor or other device that can mix the steam and liquid in the pipe. The heated part 106D of the main circulation stream 106 can then be flashed through a pressure drop device 107 to form steam in pail 106E of the circulation stream which can then be introduced to the flash sparger 108 in the flash vessel 103 where the steam and liquid are separated. The pressure drop device can be an orifice plate, valve, or other device that creates a pressure drop. The pressure drop device is where much of the cell lysing can occur due to the high temperatures and change from high to low pressure. Temperatures in the main circulation stream can range from 150 to 300 degrees Fahrenheit which is sufficient to destroy all pathogens that were introduced into the system 200 via the biologically contamination water stream 201. To increase efficiency, a portion of the steam from the flash vessel 103 can be captured and directed through line 109 to enter a mist eliminator 110 where any mist is separated from the steam. Liquid and solids recovered from the mist eliminator is directed through line 111 to be reintroduced to the flash vessel. The dry steam from the mist eliminator can be directed through line 112 to be compressed in the blower 113. For example, the pressure on the outlet of the blower can be between 5 and 30 PSIG. The blower can be a rotary lobe, fan, centrifugal, or other type of compressor. The compressed steam from the blower is then directed through line 214 to be reintroduced to the main circulation 106 via the steam sparger 215 A, as mentioned above. This process of steam capture and reintroduction helps to recover latent heat in the system 200 to increase its overall efficiency.

[0084] The portion of steam from the flash vessel 103 that is not directed to the mist eliminator 110 can be received by the ammonia enrichment unit 130. The ammonia enrichment unit includes packing 137 and a liquid distribution device 132, which can concentrate ammonia at the top of the unit in an ammonia-enriched stream 133. The ammonia-enriched stream flows to an ammonia processing unit 134, which also receives an acid stream 135. The acid reacts with the ammonia to form an ammonium salt that flows out as a product stream 136.

[0085] As mentioned above, hot treated water 118 from the main circulation 106 is separated from the circulation line and is directed to the preheater 101 where it heats the biologically contaminated water feed 201 while cooling the treated water outlet stream 119. The preheater 101 can be a plate and frame, spiral, shell and tube, or other type of heat exchanger.

[0086] FIG. 8 is a schematic block diagram illustrating another embodiment of a system 200 to provide water treatment services. The system shown in FIG. 8 is similar to FIGS. 6 and 7, and like parts are labeled using like identifiers. The system is operable to treat contaminated water by lysing cell walls, thus making the water easier to filter and therefore minimizing the solids to dispose. The system is further operable to destroy dangerous pathogens by temperature and residence time in accordance with EPA specifications, further contributing to making the solids easier to dispose.

[0087] The system 200 can include a biologically contaminated water feed stream 201 entering the system and a treated water stream 119 leaving the system. The biologically contaminated water feed stream can come from any upstream equipment or processes that produces contaminated water such as but not limited to waste activated sludge digesters, filters, centrifuges, hospitals, pharmaceutical manufacturing, food plants, etc. Furthermore, the contaminated water stream can contain from 0% to 30% solids. The treated water leaving the system can be sent for further treating or solids separation, which is not shown here. The solids content and volume of the treated water can be the same or slightly more than the contaminated feed stream.

[0088] The system 200 takes the biologically contaminated water stream 201 and preheats it in a preheater exchanger 101 using the hot treated water stream 118 as a heat source. This recovers heat from the system and makes the system more efficient, thus helping to reduce energy costs associated with the system. The preheated biologically contaminated water stream 102 then joins a circulation stream 106.

[0089] The circulation of the contaminated water in the circulation stream 106 will now be described beginning with a flash vessel 103 shown in FIG. 8. The liquid in the bottom of the flash vessel exits the flash vessel to the circulation pump 105 suction via a line 104.

[0090] The circulation pump 105 is operable to raise the pressure of the contaminated water in the circulation stream 106. For example, the circulation pump can increase the pressure of the circulation stream by 15 to 100 PSIG. The flow rate through the circulation pump can be, for example, from 5 to 400 times the flow rate of the biologically contaminated water feed 201. The circulation pump discharges into the circulation stream 106. The main circulation then splits into a part 106 A of the main circulation stream and into a hot treated water stream 118 that then enters the heat exchanger 101 and exits the system 200 as the treated water stream 119, as described above.

[0091] The circulation pump 105 can be a centrifugal, positive displacement, diaphragm, or other type of pump. The preheated contaminated water feed 102 joins with pail 106A of the main circulation stream 106 to form pail 106B of the main circulation stream.

[0092] As shown in FIG. 8, part 106B of the circulation stream 106 can be directed into a heat exchanger 321. The heat exchanger comprises a heat input 316 that is taken from an external source to provide heat to the heat exchanger. A return line 322 is provided exiting the heat exchanger. In some embodiments, the heat input and the return line can be part of a closed loop fluid flow to bring heat to the system 3 from an external source. The heat exchanger adds heat energy to the main circulation stream which exits the heat exchanger at part 106C of the main circulation stream.

[0093] Compressed steam 114 from a blower 113 can be injected via a steam sparger 115 into the main circulation 106 at part 106C to further heat the main circulation stream at part 106D. The steam sparger 115 can be a perforated pipe, eductor, or other device that can mix the steam and liquid in the pipe. The heated part 106D of the main circulation stream 106 can then be flashed through a pressure drop device 107 to form steam in part 106E of the circulation stream which can then be introduced to the flash sparger 108 in the flash vessel 103 where the steam and liquid are separated. The pressure drop device can be an orifice plate, valve, or other device that creates a pressure drop. The pressure drop device is where much of the cell lysing can occur due to the high temperatures and change from high to low pressure. Temperatures in the main circulation stream can range from 150 to 300 degrees Fahrenheit which is sufficient to destroy all pathogens that were introduced into the system 200 via the biologically contamination water stream 201.

[0094] In some embodiments, the pressure increase on the circulation stream can induce or cause lysing of cellular microorganisms (e.g. bacteria). In other embodiments, the drop or change in pressure on the circulation stream can be induce or otherwise cause lysing of cellular microorganisms. In yet another embodiment, the heat exerted on the circulation stream can induce or otherwise cause lysing of cellular microorganisms. In further embodiments, a combination of two or more of the above (e.g. pressure increase, pressure drop, or temperature) can induce or otherwise cause lysing of cellular microorganisms in the circulation stream. In some embodiments, one or more of these conditions (e.g. any individually, any combination of two, or a combination of all three) can be sufficient to between 5% and 100% of cellular microorganisms in the circulation stream. In another embodiment, one or more of these conditions or events can be sufficient to lyse from 20% to 100% of cellular microorganism in the circulation stream. In another embodiment, the amount of cellular microorganisms lysed can be greater than 50%, 60%, 70%, 80%, 90%, or 95%. In some embodiments, one or more of these conditions or events can kill, destroy, or otherwise deactivate or inactivate other non-ccllular pathogens in the circulation stream, such as viruses and other nucleic acid materials (e.g. by denaturation, etc.). As previously mentioned, the lysing of cellular materials, including cellular microorganisms and release of liquid (e.g. water) and other internal materials can dramatically reduce the resultant solids output by the system and allow further recapture or diversion of water.

[0095] To increase efficiency, steam from the flash vessel 103 can be captured and directed through line 109 to enter a mist eliminator 110 where any mist is separated from the steam. Liquid recovered from the mist eliminator is directed through line 111 to be reintroduced to the flash vessel. The dry steam from the mist eliminator can be directed through line 112 to be compressed in the blower 113. For example, the pressure on the outlet of the blower can be between 5 and 30 PSIG. The blower can be a rotary lobe, fan, centrifugal, or other type of compressor. The compressed steam from the blower is directed through line 114 to be reintroduced to the main circulation stream 106 at part 106C via the steam sparger 115, as mentioned above. This process of steam capture and reintroduction helps to recover latent heat in the system 200 to increase its overall efficiency.

[0096] As mentioned above, hot treated water 118 from the main circulation 106 is separated from the circulation line and is directed to the preheater 101 where it heats the biologically contaminated water feed 201 while cooling the treated water outlet stream 119. The preheater can be a plate and frame, spiral, shell and tube, or other type of heat exchanger.

[0097] The present disclosure also describes methods of separating ammonia from an aqueous stream. The methods can utilize any of the systems and equipment described above. In one example, a method of separating ammonia from an aqueous stream can include flashing the aqueous stream in a flash vessel to separate a flashed vapor from liquid in the aqueous stream. Ammonia can be concentrated from the flashed vapor in an ammonia-enriched stream at an upper portion of an ammonia enrichment unit. The ammonia enrichment unit can be disposed at an upper portion of the lash vessel. The ammonia enrichment unit can comprise a mass transfer device configured to separate the ammonia-enriched stream from a bottoms liquid having a lower concentration of ammonia than the ammonia-enriched stream.

[0098] In some examples, the mass transfer device can comprise random packing, structured packing, or a combination thereof. The mass transfer device can also, or alternatively, include a liquid distributor, distillation column trays, a reflux line, a reflux condenser, or a combination thereof. The method of separating ammonia can also include refluxing a portion of the ammonia-enriched stream to the ammonia enrichment unit. The refluxed portion of the ammonia-enriched stream can also be condensed and returned into the ammonia enrichment unit as a liquid. The method can also include returning the bottoms liquid to the aqueous stream in the flash vessel.

[0099] In further examples, the method can include converting ammonia in the ammonia- enriched stream to an ammonium salt. This can be accomplished by reacting the ammonia with an acid selected from the group consisting of sulfuric acid, nitric acid, hydrochloric acid, and combinations thereof.

[0100] The methods can also include removing steam from the flash vessel through a steam outlet located below the ammonia enrichment unit in the flash vessel, compressing the steam, and reintroducing the steam into the aqueous stream. Additionally, liquid can be extracted from the steam using a mist separator before compressing the steam. The steam can be reintroduced into the aqueous stream using a steam sparger to sparge the compressed steam into the aqueous stream.

[0101] In certain examples, the aqueous stream that is used in the methods can be a biologically contaminated water stream. In some such methods, the method can also include recirculating the separated liquid from the flash vessel using a circulation pump that pressurizes the separated liquid into a circulation stream, passing the circulation stream through a heat exchanger to preheat the biologically contaminated water stream, and lowering the pressure of the biologically contaminated water stream using a pressure drop device prior to receipt by the flash vessel.

[0102] Any of the various features and components of the systems described above can also be used in the methods described herein. Similarly, any equipment or features described in the methods can be incorporated in the systems described herein.

[0103] Example Embodiments

[0104] The following examples embodiments pertain to specific technology embodiments and point out specific features, elements, or steps that may be used or otherwise combined in achieving such embodiments.

[0105] In Example 1 there is provided a system for removing ammonia from an aqueous stream which comprises a flash vessel configured to receive an aqueous stream and to separate a flashed vapor from liquid in the aqueous stream and an ammonia enrichment unit disposed at an upper portion of the flash vessel configured to receive the flashed vapor, wherein the ammonia enrichment unit comprises a mass transfer device configured to separate an ammonia-enriched stream at an upper portion of the ammonia enrichment unit from a bottoms liquid having a lower concentration of ammonia than the ammonia-enriched stream.

[0106] In Example 2, the mass transfer device of example 1 comprises random packing, structured packing, or a combination thereof.

[0107] In Example 3, the mass transfer device of any preceding example comprises a liquid distributor.

[0108] In Example 4, the mass transfer device of any preceding example comprises distillation column trays.

[0109] In Example 5, the number of distillation column trays in Example 4 is from 1 to 10.

[0110] In Example 6, the mass transfer device of any preceding example includes a reflux line configured to recycle a portion of the ammonia-enriched stream to the ammonia enrichment unit.

[0111] In Example 7, the system of Example 6, further comprises a reflux condenser configured to condense the portion of the ammonia-enriched stream such that the portion of the ammonia-enriched stream is returned into the ammonia enrichment unit as a liquid.

[0112] In Example 8, the mass transfer device of any preceding example is further configured to return the bottoms liquid to the aqueous stream in the flash vessel.

[0113] In Example 9, the ammonia enrichment unit of any preceding example comprises a column.

[0114] In Example 10, the column of example 9 extends from an upper housing of the flash vessel and wherein the column has a smaller diameter than the flash vessel.

[0115] In Example 11, the system any preceding example, further comprises an ammonia processing unit configured to receive the ammonia-enriched stream.

[0116] In Example 12, the ammonia processing unit of example 11 is configured to convert ammonia in the ammonia-enriched stream into an ammonium salt.

[0117] In Example 13, the system any preceding example, further comprises an acid stream configured to supply an acid to the ammonia processing unit to react with the ammonia to form the ammonium salt. In Example 14, the flash vessel of any preceding example further comprises a steam outlet located below the ammonia enrichment unit.

[0118] In Example 15, the system of any preceding example further comprises a blower configured to receive the steam from the steam outlet and compress the separated steam for reintroduction into the aqueous stream.

[0119] In Example 16, the system of any preceding example further comprises a mist separator disposed between the steam outlet and the blower, the mist separator operable to extract liquid from the steam.

[0120] In Example 17, the system of any preceding example further comprises a steam sparger configured to sparge the compressed steam into the aqueous stream.

[0121] In Example 18, the aqueous stream of any preceding example is a biologically contaminated water stream.

[0122] In Example 19, the system of any preceding example further comprises a circulation pump configured to receive the separated liquid from the flash vessel and to pressurize the separated liquid into a circulation stream; a preheater exchanger configured to receive the circulation stream and preheat the biologically contaminated water stream; and a pressure drop device configured to lower the pressure of the biologically contaminated water stream prior to receipt by the flash vessel.

[0123] In Example 20, there is provided a method of separating ammonia from an aqueous stream, comprising flashing the aqueous stream in a flash vessel to separate a flashed vapor from liquid in the aqueous stream; and concentrating ammonia from the flashed vapor in an ammonia-enriched stream at an upper portion of an ammonia enrichment unit, wherein the ammonia enrichment unit is disposed at an upper portion of the lash vessel, wherein the ammonia enrichment unit comprises a mass transfer device configured to separate the ammonia-enriched stream from a bottoms liquid having a lower concentration of ammonia than the ammonia-enriched stream.

[0124] In Example 21, the mass transfer device of Example 20 comprises random packing, structured packing, or a combination thereof.

[0125] In Example 22, the mass transfer device of cither of Examples 20 or 21 comprises a liquid distributor. In Example 23, the mass transfer device of any of Examples 20-22 comprises distillation column trays.

[0126] In Example 24, the method of any of examples 20-23 further comprises refluxing a portion of the ammonia-enriched stream to the ammonia enrichment unit.

[0127] In Example 25, the method of any of examples 20-24 further comprises condensing the portion of the ammonia-enriched stream and returning the portion of the ammonia- enriched stream into the ammonia enrichment unit as a liquid.

[0128] In Example 26, the method of any of examples 20-25, further comprises returning the bottoms liquid to the aqueous stream in the flash vessel.

[0129] In Example 27, the method of any of examples 20-26 further comprises converting ammonia in the ammonia-enriched stream to an ammonium salt.

[0130] In Example 28, the ammonia of example 27 is converted to the ammonium salt by reacting the ammonia with an acid selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, citric acid and combinations thereof.

[0131] In Example 29, the method of any of examples 20-28 further comprises removing steam from the flash vessel through a steam outlet located below the ammonia enrichment unit in the flash vessel, compressing the steam, and reintroducing the steam into the aqueous stream.

[0132] In Example 30, the method of any of examples 20-29 further comprises extracting liquid from the steam using a mist separator before compressing the steam.

[0133] In Example 31 , the steam in example 30 is reintroduced into the aqueous stream using a steam sparger to sparge the compressed steam into the aqueous stream.

[0134] In Example 32, the aqueous stream of any of examples 20-31 is a biologically contaminated water stream.

[0135] In Example 33, the method of example 32, further comprises recirculating the separated liquid from the flash vessel using a circulation pump that pressurizes the separated liquid into a circulation stream; passing the circulation stream through a heat exchanger to preheat the biologically contaminated water stream; and lowering the pressure of the biologically contaminated water stream using a pressure drop device prior to receipt by the flash vessel. While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

Claims

CLAIMSWhat is claimed is:

1. A system for removing ammonia from an aqueous stream comprising: a flash vessel configured to receive an aqueous stream and to separate a flashed vapor from liquid in the aqueous stream and an ammonia enrichment unit disposed at an upper portion of the flash vessel configured to receive the flashed vapor, wherein the ammonia enrichment unit comprises a mass transfer device configured to separate an ammonia-cnrichcd stream at an upper portion of the ammonia enrichment unit from a bottoms liquid having a lower concentration of ammonia than the ammonia-enriched stream.

2. The system of claim 1, wherein the mass transfer device comprises random packing, structured packing, or a combination thereof.

3. The system of claim 1, wherein the mass transfer device comprises a liquid distributor.

4. The system of claim 1, wherein the mass transfer device comprises distillation column trays.

5. The system of claim 4, wherein the mass transfer device comprises a number of distillation column trays from 1 to 10.

6. The system of claim 1, wherein the mass transfer device includes a reflux line configured to recycle a portion of the ammonia-enriched stream to the ammonia enrichment unit.

7. The system of claim 6, further comprising a reflux condenser configured to condense the portion of the ammonia-cnrichcd stream such that the portion of the ammonia-cnrichcd stream is returned into the ammonia enrichment unit as a liquid.

8. The system of claim 1, wherein the mass transfer device is further configured to return the bottoms liquid to the aqueous stream in the flash vessel.

9. The system of claim 1, wherein the ammonia enrichment unit comprises a column.

10. The system of claim 9, wherein the column extends from an upper housing of the flash vessel and wherein the column has a smaller diameter than the flash vessel.

11. The system of claim 1, further comprising an ammonia processing unit configured to receive the ammonia-cnrichcd stream.

12. The system of claim 11, wherein the ammonia processing unit is configured to covert ammonia in the ammonia-enriched stream into an ammonium salt.

13. The system of claim 12, further comprising an acid stream configured to supply an acid to the ammonia processing unit to react with the ammonia to form the ammonium salt.

14. The system of claim 1, wherein the flash vessel further comprises a steam outlet located below the ammonia enrichment unit.

15. The system of claim 14, further comprising a blower configured to receive the steam from the steam outlet and compress the separated steam for reintroduction into the aqueous stream.

16. The system of claim 15, further comprising a mist separator disposed between the steam outlet and the blower, the mist separator operable to extract liquid from the steam.

17. The system of claim 16, further comprising a steam sparger configured to sparge the compressed steam into the aqueous stream.

18. The system of claim 1, wherein the aqueous stream is a biologically contaminated water stream.

19. The system of claim 18, wherein the system further comprises: a circulation pump configured to receive the separated liquid from the flash vessel and to pressurize the separated liquid into a circulation stream; a preheater exchanger configured to receive the circulation stream and preheat the biologically contaminated water stream; and a pressure drop device configured to lower the pressure of the biologically contaminated water stream prior to receipt by the flash vessel.

20. A method of separating ammonia from an aqueous stream, comprising: flashing the aqueous stream in a flash vessel to separate a flashed vapor from liquid in the aqueous stream; and concentrating ammonia from the flashed vapor in an ammonia-enriched stream at an upper portion of an ammonia enrichment unit, wherein the ammonia enrichment unit is disposed at an upper portion of the lash vessel, wherein the ammonia enrichment unit comprises a mass transfer device configured to separate the ammonia-enriched stream from a bottoms liquid having a lower concentration of ammonia than the ammonia-enriched stream.

21. The method of claim 20, wherein the mass transfer device comprises random packing, structured packing, or a combination thereof.

22. The method of claim 20, wherein the mass transfer device comprises a liquid distributor.

23. The method of claim 20, wherein the mass transfer device comprises distillation column trays.

24. The method of claim 20, further comprising refluxing a portion of the ammonia-enriched stream to the ammonia enrichment unit.

25. The method of claim 24, further comprising condensing the portion of the ammonia- enriched stream and returning the portion of the ammonia-enriched stream into the ammonia enrichment unit as a liquid.

26. The method of claim 20, further comprising returning the bottoms liquid to the aqueous stream in the flash vessel.

27. The method of claim 20, further comprising converting ammonia in the ammonia- enriched stream to an ammonium salt.

28. The method of claim 27, wherein the ammonia is converted to the ammonium salt by reacting the ammonia with an acid selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, citric acid and combinations thereof.

29. The method of claim 20, further comprising removing steam from the flash vessel through a steam outlet located below the ammonia enrichment unit in the flash vessel, compressing the steam, and reintroducing the steam into the aqueous stream.

30. The method of claim 29, further comprising extracting liquid from the steam using a mist separator before compressing the steam.

31. The method of claim 30, wherein the steam is reintroduced into the aqueous stream using a steam sparger to sparge the compressed steam into the aqueous stream.

32. The method of claim 20, wherein the aqueous stream is a biologically contaminated water stream.

33. The method of claim 32, further comprising: recirculating the separated liquid from the flash vessel using a circulation pump that pressurizes the separated liquid into a circulation stream;passing the circulation stream through a heat exchanger to preheat the biologically contaminated water stream; and lowering the pressure of the biologically contaminated water stream using a pressure drop device prior to receipt by the flash vessel.

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