Systems and methods for treating biologically contaminated water streams - Patents.com

Abstract

[Solution] A system for treating a biologically-contaminated stream to lyse pathogens within the biologically-contaminated stream is provided, the system including a flash vessel configured to receive the biologically-contaminated stream and separate steam from liquid in the biologically-contaminated stream, a blower configured to receive the separated steam from the flash vessel and compress the separated steam for reintroduction into the biologically-contaminated stream, a circulation pump configured to receive the separated liquid from the flash vessel and pressurize the separated liquid into a circulating stream, a preheat exchanger configured to receive treated water from the circulating stream and preheat the biologically-contaminated stream, and a pressure reduction device configured to reduce the pressure of the biologically-contaminated stream prior to receipt by the flash vessel.

Description

[Technical field]

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 145,912, filed February 4, 2021, which is incorporated herein by reference.

[0002] The present disclosure relates to the treatment of biologically contaminated water, for example in municipal or industrial water treatment plants. More specifically, the present disclosure relates to systems and methods for cell lysis of biologically contaminated water, destruction of pathogens in biologically contaminated water, and dewatering of biologically contaminated water streams. [Background technology]

[0003] Contaminated water with high levels of organic matter, measured in terms of Biological Oxygen Demand (BOD), often undergoes a biological treatment process to remove the organic matter from the contaminated water. This process creates an environment favorable for the exponential growth of biological organisms, mainly bacteria, which utilize the organic waste in the contaminated water for cell reproduction. As a result of the biological treatment process, the organic matter is removed from the water (reducing the BOD level in the water) and a large number of biological organisms are produced. One type of biomass produced is often called activated sludge. The excess biomass produced is called waste activated sludge (WAS).

[0004] One problem associated with such biological treatment processes concerns the final disposal of the solids in the contaminated waste. WAS, i.e., biomass that is no longer needed in a biological treatment process, is typically disposed of as a reusable product (as fertilizer) or in a landfill. However, WAS is not a waste that can be simply disposed of. This is because WAS contains pathogens (disease-causing bacteria) and it also tends to retain water. Therefore, it is difficult to reduce the total volume of WAS using conventional water separation techniques. Disposal of WAS is a major problem, as almost every municipal wastewater treatment plant in the United States (approximately 16,000 of them) generates WAS every day.

[0005] In many locations in the United States, WAS is dewatered to a solids content of about 20% and a moisture content of about 80%. It is then sent to a landfill for disposal. Larger municipal facilities often use digesters to treat WAS, which produces natural gas for energy production, slightly reduces final disposal volumes, and, most importantly, destroys pathogens, making WAS safer for reuse applications. However, even with digesters, WAS dewatering does not improve; that is, a ratio of about 20% solids to 80% moisture remains.

[0006] Assuming a standard-sized wastewater treatment plant (one of 16,000 systems in the United States) produces 3,000 pounds of dry WAS per day, this means that approximately 15,000 pounds of dewatered WAS are shipped for reuse or disposal per day. The cost of disposing of WAS in landfills across the United States is rising and is consistently above $50 per ton. This creates significant costs for wastewater treatment plants across the country. Summary of the Invention [Means for solving the problem]

[0007] The inventors have found it advantageous to develop a system that can condition the sludge like a digester by destroying pathogens. Additionally, there is a need for a system that can dewater the WAS to a higher solids / moisture ratio to reduce disposal costs and increase the potential for reuse.

[0008] The systems and methods described in this disclosure are operable to treat and condition biological wastewater streams (such as WAS) with solids to moisture ratios of up to 4% to 96% or more. Such conditioning of the biological wastewater stream prepares it for further processing through digesters and / or dewatering techniques. The systems and methods described herein enhance both the digestion and dewatering processes. In applications using digesters, the systems and methods can increase the processing rate, thereby allowing the digester to handle a higher flow rate in a smaller digester size. Other benefits include an expected increase in biogas (methane) production of an additional 25% when used in combination with an anaerobic digester. Additionally, an expected reduction in solids production of an additional 25% when used in combination with an aerobic or anaerobic digester. For dewatering, the systems and methods can improve the dewaterability of the biological wastewater stream to reduce the overall volume of material to be disposed of. It is estimated that the benefits of improved digestion and dewatering outweigh the additional operating and energy costs associated with the systems and methods described herein.

[0009] In one example, a system for treating a biological wastewater stream to lyse pathogens therein is provided that includes a flash vessel configured to receive the biological wastewater stream and separate vapor from liquid in the biological wastewater stream, a blower configured to receive the separated vapor from the flash vessel and compress the separated vapor for reintroduction into the biological wastewater stream, a circulation pump configured to receive the separated liquid from the flash vessel and pressurize the separated liquid into a circulating stream, a preheat exchanger configured to receive treated water from the circulating stream and preheat the biological wastewater stream, and a pressure reduction device configured to reduce the pressure of the biological wastewater stream prior to receipt by the flash vessel.

[0010] In one example, the system may further include a mist separator disposed between the flash vessel and the blower, the mist separator may be operable to extract liquid from the separated vapor.

[0011] In one example, a biologically contaminated wastewater stream joins the circulating stream between the circulating pump and the pressure let down device. The treated water is separated from the circulating stream between the pump and the joining of the circulating stream with the biologically contaminated wastewater stream. Further, a heat exchanger can be provided operable to heat the biologically contaminated wastewater stream before it is directed to the pressure let down device.

[0012] In another example, a system is provided for treating a biologically-contaminated wastewater stream to lyse pathogens therein. The system can include a heat source configured to add heat to a circulating stream having a biologically-contaminated stream containing pathogens and solids, a flash vessel configured to receive the circulating stream and separate vapor from liquid from the circulating stream, and a blower configured to receive the separated vapor from the flash vessel. The blower can compress the separated vapor and then reintroduce the separated vapor into the circulating stream to recover the latent heat of vaporization.

[0013] The system may further include a circulation pump configured to receive the separated liquid from the flash vessel and pressurize the separated liquid into the circulating stream, and a pressure let-down device configured to reduce the pressure of the circulating stream before the flash vessel receives the circulating stream. The pressure let-down device and the circulating pump may cause cell wall destruction of pathogenic bacteria in the circulating stream. The system may further include a preheat exchanger configured to receive treated water from the circulating stream and recover heat from the treated water by preheating an inlet water to be added to the circulating stream.

[0014] In one example, the heat source is a heat exchanger. In another example, the heat source includes adding make-up steam to the circulating stream.

[0015] In one example, the separated vapor is reintroduced into the circulation stream between the flash vessel and the circulation pump.

[0016] In another example, a method for recovering water from pathogens in biologically contaminated water vapor is provided, the method comprising the steps of preheating a biologically contaminated water stream using heat from a treated water stream, adding the preheated biologically contaminated water stream to a circulating stream, pressurizing and heating the circulating stream, reducing the pressure of the circulating stream, separating vapor from liquid in the circulating stream, compressing the vapor and reintroducing the vapor into the circulating stream, and discharging the treated water stream from the circulating stream.

[0017] In one example, the recycle stream is pressurized between separation of the vapor from the liquid and adding the pre-heated biologically-contaminated water stream to the recycle stream.

[0018] In one example, the method can further include adding additional heat to the circulating stream after adding the preheated biologically-contaminated water stream to the circulating stream. The method can also include extracting a liquid stream from the vapor prior to compressing the vapor and adding the liquid stream to the circulating stream. In one example, the vapor can be reintroduced into the circulating stream prior to pressurizing the circulating stream. [Brief description of the drawings]

[0019] Additional features and advantages of embodiments of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, features of the invention. [Figure 1] FIG. 1 is a schematic diagram of a system for treating biologically contaminated water in an exemplary embodiment. [Diagram 2] FIG. 2 is a schematic diagram of a system for treating biologically contaminated water in an exemplary embodiment. [Diagram 3] 3 is a schematic diagram of a system for treating biologically contaminated water in an exemplary embodiment. Reference will now be made to the exemplary embodiment illustrated, and specific terminology will be used herein to describe the same, with the understanding that they are not intended to limit the scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Before describing the embodiments of the present invention, it is to be understood that the present disclosure is not limited to the specific configurations, process steps, or materials disclosed herein, but extends to equivalents thereof that would be recognized by those skilled in the relevant art. It is also to be understood that the terminology used herein is used only for the purpose of describing specific examples or embodiments, and is not intended to be limiting. The same reference numbers in different drawings represent the same elements. The numbers provided in the flow charts and processes are provided for clarity in the description of the steps and operations, and do not necessarily indicate a particular order or sequence.

[0021] Furthermore, the described features, structures, or characteristics may 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, formulations, processes, and the like, to provide a thorough understanding of various embodiments of the present invention. However, those skilled in the art will recognize that such specific embodiments are not limiting of the overall inventive concept set forth 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, a reference to a "stream" includes a reference to one or more such streams, and a reference to an "organism" includes a reference to one or more such organisms.

[0023] In this disclosure, "comprise," "comprising," "containing," "having," and the like can have the meanings given to them in U.S. patent law, and also mean "includes," "including," and the like, and are generally construed as open-ended terms. The terms "consisting of" or "consists of" are closed terms, including only those components, configurations, steps, and the like specifically recited in association with such terms, and are in accordance with U.S. patent law. "Consisting essentially of" or "consists essentially of" have the meanings generally given by U.S. patent law. In particular, although such terms are generally closed terms, there are exceptions that permit the inclusion of additional items, materials, components, steps, or elements that do not materially affect the basic and novel characteristics or function of the item in association therewith. For example, trace elements that are present in the composition but do not affect the nature or properties of the composition would be permitted under the term "consisting essentially of" even if they are not expressly recited in the list of items following such terms. When open-ended terms such as "having" or "including" are used in the description herein, it will be understood that direct support should be provided for the phrase "consisting of," as well as the phrase "consisting essentially of," as if expressly set forth above, or vice versa.

[0024] The terms "first," "second," "third," "fourth," etc., used in the specification and claims are used to distinguish between similar elements and are not necessarily used to describe a particular sequential or chronological order. It should be understood that any such terms used may be interchanged under appropriate circumstances, such as when the embodiments described herein can operate in sequences other than those shown or otherwise described herein. Similarly, when a method is described as having a series of steps, the order of such steps presented is not necessarily the only order in which such steps may be performed, and some of the described steps may optionally be omitted and / or certain other steps not described herein may be added to the method.

[0025] 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 in the surrounding or adjacent area, similarly located, in a single device or composition, or in multiple comparable devices or compositions, in a group or class, in multiple groups or classes, or by comparison to the known state of the art.

[0026] As used herein, the term "microorganism" refers to any organism that is too small to be seen individually by the naked eye. Some microorganisms may contain a cell wall or other membrane that contains cellulose or lipid structures that house components such as internal organelles and nucleic acids, and may further contain water or other liquids. Examples of such microorganisms may include, but are not limited to, algae, bacteria, spores, viruses, protozoa, etc. As used herein, the term "pathogen" refers to any disease-promoting microorganism.

[0027] As used herein, "biological wastewater," "biologically contaminated wastewater," and "biologically contaminated water" may be used interchangeably, and these and similar terms refer to a composition or solution (e.g., an aqueous solution) that contains a measurable amount of at least one microorganism.

[0028] As used herein, the term "coupled" is defined as directly or indirectly connected in a chemical, mechanical, electrical, or non-electrical manner. Objects described herein as "adjacent" one another may be in physical contact with one another, in close proximity to one another, or in the same general region or area as one another, depending on the context in which the phrase is used. Objects or elements that are "directly coupled" are in physical contact with one another.

[0029] The appearances of the phrases "in one embodiment" or "in one aspect" in this specification 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, property, attribute, state, configuration, item, or result. For example, an object that is "substantially" enclosed means that the object is completely enclosed or nearly completely enclosed. The exact allowable range of deviations from absolute completeness may depend on the particular circumstances in some cases. Generally speaking, however, near perfection results in the same overall result as absolute and complete completion would. The use of "substantially" also applies when used in a negative sense, referring to the complete or nearly complete absence of an action, property, attribute, state, configuration, item, or result. For example, a composition that is "substantially free" of particles is completely devoid of particles or nearly completely devoid of particles, which has the same effect as the complete absence of particles. That is, a composition that is "substantially free" of a component or element may still actually contain such an item, so long as there is no measurable effect of it.

[0031] As used herein, the term "about" is used to provide flexibility in that a given value may be "slightly greater" or "slightly less" than the endpoints of a certain numerical range. Unless otherwise specified, the use of the term "about" in conjunction with a particular number or numerical range should be understood to support such numerical term or range without the term "about." For example, for convenience and brevity, a numerical range of "about 50 angstroms to 80 angstroms" should be understood to support the range "50 angstroms to 80 angstroms." Furthermore, it should be understood that when the term "about" is used herein, the actual numerical value is supported. For example, a description of "about" 30 should be interpreted to support values ​​slightly above and slightly below 30 as well as the actual numerical value of 30.

[0032] In this specification, a number of items, components, compositional elements, and / or materials may be presented in common lists for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. As such, individual members of such lists and any other members of the same list should not be construed as de facto equivalents based solely on their representation within a common group, unless expressly stated otherwise.

[0033] Concentrations, amounts, levels and other numerical data may be expressed or presented in a range format herein. Such range formats are used merely for convenience and brevity, and it should be understood that such range formats should be interpreted flexibly to include not only the numerical values ​​explicitly recited as limits of the range, but also all individual numerical values ​​or subranges or fractional units contained within the range, as if each numerical value and subrange were explicitly recited. As an example, a numerical range of "about 1 to about 5" should be interpreted not only to include the explicitly recited values ​​of about 1 to about 5, but also to include each value and subrange within the recited range. Thus, this numerical range includes each value, e.g., 2, 3, 4, and subranges, e.g., 1 to 3, 2 to 4, 3 to 5, etc., as well as each 1, 2, 3, 4, and 5. This same principle also applies to ranges recited with only one numerical value as the minimum or maximum value. Moreover, such interpretation should be applied regardless of the width or characteristics of the range being recited.

[0034] References throughout this specification to "one example" mean that a particular feature, structure, or characteristic described in connection with that example is included in at least one embodiment. Thus, appearances of the phrase "in one example" in various places throughout this specification are not necessarily all referring to the same embodiment.

[0035] This disclosure describes a thermal system that uses heat to break down (lyse) biological (e.g., bacterial) cells in biologically contaminated water, such as waste activated sludge (WAS). For example, raising the temperature of the liquid above 100°C weakens and begins to burst the bacterial cell walls. Furthermore, rapid changes in pressure cause the bacterial cells to expand and / or contract based on the external pressure exerted on the cells, further weakening and breaking down the cell walls. The systems and methods disclosed herein can use either or both techniques to lyse cells in the contaminated water, thereby releasing water trapped within the cells. Additionally, the increased temperature and rapid pressure changes denature large chain polymers and complex organic molecules in the contaminated water.

[0036] As described in more detail below, the present disclosure can use the addition of steam and pressure to heat the contaminated water in the system above its boiling point at standard atmospheric pressure. The system can then use a pump to circulate the boiled contaminated water through an orifice. This can continually increase and decrease the pressure of the liquid, which in turn increases and decreases the pressure on the cell walls of organisms in the contaminated water. Additionally, steam generated by active boiling in the system can be collected, compressed through a blower, and reinjected into the liquid stream. This can recover the latent heat of vaporization from the boiled solution, improving efficiency.

[0037] The system can achieve cell lysis and denaturation of the contaminated water while keeping in mind the energy conservation. The outgoing contaminated water can be sent to a heat exchanger that can recover heat energy by transferring it back to the incoming contaminated water. Additionally, as mentioned above, the liberated water in the form of steam can be compressed and reinjected into the incoming contaminated water to recover the latent heat of vaporization. Overall, it is estimated that the system can cause complete cell destruction of the contaminated water stream with an energy demand of about 500 KWH per ton of dry contaminated water solids. With a typical energy cost of $0.08 / KWH, this comes to a cost of $40 per ton of dry contaminated water solids. For comparison, the estimated cost of treating wet contaminated water solids is $50 per ton (which can be 5 times the volume of the dry ton), a typical rate for landfill disposal in this country. Comparing these two values, disposal costs can be significantly reduced by using the system and method described herein. Considering that pathogens are also killed in the contaminated water, the product can be considered for landfill disposal as well as the possibility of reuse is increased.

[0038] As mentioned above, the system can be used in combination with a digester. The system can increase the treatment rate, which allows the digester to handle a larger flow rate in a smaller size digester. In some examples, the system can be implemented as a pre-treatment before the digester to manage the flow of biologically contaminated wastewater streams into the digester. In some examples, the system can be configured as a slipstream that circulates from the back to the front of the digester. In some examples, the digester can be an anaerobic digester.

[0039] Non-limiting examples of systems and methods will now be described with reference to the drawings. Figure 1 is a schematic block diagram illustrating one embodiment of a system for providing water treatment services. A system 1 is provided that is operable to treat contaminated water by dissolving cell walls to release water and fluids within the cells, thereby facilitating filtration of the water and thus minimizing solids for disposal. The system 1 is further operable to destroy dangerous pathogens by temperature and residence time in accordance with EPA specifications, further contributing to ease of disposal of solids.

[0040] The system 1 can include a biologically contaminated water feed stream 100 entering the system 1 and a treated water stream 119 exiting the system 1. The biologically contaminated water feed stream 100 can come from any upstream device or process that generates 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. Also, the contaminated water stream 100 can contain different concentration ranges of solids (e.g., 0%-30%). The treated water 119 exiting the system 1 can be sent for further processing or solids separation, which is not shown here. The solids content and volume of the treated water 119 can be the same as or slightly higher than the contaminated feed steam 100.

[0041] System 1 takes in a biologically contaminated water stream 100 and preheats it in a preheat exchanger 101 using the thermal treatment water stream 118 as a heat source. This helps recover heat from the system 1 and improve the efficiency of the system 1, thus reducing the energy costs associated with the system 1. The preheated biologically contaminated water stream 102 is then combined with the recycle stream 106.

[0042] The circulation of the contaminated water in the circulation stream 106 will now be described, beginning with the flash vessel 103 shown in Figure 1. Liquid at the bottom of the flash vessel 103 leaves the flash vessel 103 and is drawn into the circulation pump 105 via line 104.

[0043] The circulation pump 105 is operable to increase the pressure of the contaminated water in the circulation stream 106. For example, the circulation pump 105 may increase the pressure of the circulation stream 106 from about 15 PSIG to about 100 PSIG. The flow rate through the circulation pump 105 may be, for example, about 5 times to about 400 times the flow rate of the biologically contaminated water supply 100. The circulation pump 105 discharges into the circulation stream 106. The main circulation stream 106 then branches into a portion 106A of the main circulation stream 106 and a thermally treated water stream 118 which then enters the heat exchanger 101 and exits the system 1 as treated water stream 119 as described above.

[0044] Circulation pump 105 may be a centrifugal pump, a positive displacement pump, a diaphragm pump, or other type of pump. The preheated contaminated water supply 102 joins with portion 106A of main circulation flow 106 to form portion 106B of main circulation flow 106. Compressed steam 114 from blower 113 may be injected into portion 106B of main circulation flow 106 via steam sparger 115 to heat portion 106C of main circulation flow 106.

[0045] Make-up steam 116 can be introduced into the main circulation 106C via steam sparger 117 to provide supplemental heat to the portion 106D of the circulation stream 106. Make-up steam 116 can be provided from an external source to add thermal energy to the system 1. The steam spargers 115 and 117 can be perforated pipes, eductors, or other devices capable of mixing steam and liquid in a pipe. The heated portion 106D of the main circulation stream 106 can then be forced through the pressure reduction device 107 to form steam in the portion 106E of the circulation stream 106, which can then be introduced into the flash sparger 108 in the flash vessel 103, where the steam and liquid are separated. The pressure reduction device 107 can be an orifice plate, a valve, a gate, a door, a constriction (e.g., a venturi), a filter, a joint, a bend, or any other device or configuration that creates a pressure drop. The pressure reduction device 107 is where much of the cell lysis can occur due to the change from high temperature and high pressure to low pressure. In some embodiments, the pressure drop may be from about 100 PSIG to about 50 PSIG. In some other embodiments, the drop may be from about 150 PSIG to about 15 PSIG. In some embodiments, the pressure drop may be from a higher pressure to a lower pressure, and may be from about a 10% pressure drop to about a 90% pressure drop. In other embodiments, the drop may be about 20%, 30%, 40%, 50%, 60%, 70%, 80%, or any other percentage drop therebetween, as needed to achieve a particular result. Such pressure drops may contribute significantly to the lysis of microcellular organisms, as described herein. The temperature in the main circulation stream 106 may range from 150 degrees to 300 degrees Fahrenheit, which is sufficient to destroy all pathogens introduced into the system 1 via the biologically contaminated water stream 100.

[0046] To increase efficiency, vapor from the flash vessel 103 may be captured and directed through line 109 into a mist eliminator 110 where the mist is separated from the vapor. Liquid recovered from the mist eliminator 110 is reintroduced into the flash vessel 103 through line 111. Dry vapor from the mist eliminator 110 may be directed through line 112 and compressed in a blower 113. For example, the pressure at the outlet of the blower 113 may be between 5 PSIG and 30 PSIG. The blower 113 may be a rotating lobe, fan, centrifugal, or other type of compressor. The compressed vapor from the blower 113 is directed through line 114 and reintroduced into the main circulation flow 106 of the portion 106B via a steam sparger 115 as described above. This process of capturing and reintroducing vapor helps recover latent heat in the system 1 to increase the overall efficiency.

[0047] As mentioned above, the hot treated water 118 from the main circulation 106 is separated from the circulation line 106 and directed to the preheater 101 which cools the treated water discharge stream 119 while heating the biologically contaminated water feed 119. The preheater 101 may be a plate and frame, spiral, shell and tube, or other type of heat exchanger.

[0048] FIG. 2 is a schematic block diagram illustrating another embodiment of a system for providing water treatment services. System 2 shown in FIG. 2 is similar to FIG. 1, with like parts labeled with like identifiers. System 2 is operable to treat contaminated water by dissolving cell walls, which facilitates filtration of the water, thus minimizing waste solids. System 2 is further operable to destroy dangerous pathogens by temperature and residence time in accordance with EPA specifications, further contributing to ease disposal of solids.

[0049] System 2 may include a biologically contaminated water feed stream 100 entering system 2 and a treated water stream 119 exiting system 2. Biologically contaminated water feed stream 100 may come from any upstream device or process that generates contaminated water, such as, but not limited to, waste activated sludge digesters, filters, centrifuges, hospitals, pharmaceutical manufacturing, food plants, etc. Also, the contaminated water stream 100 may contain 0%-30% solids. The treated water 119 exiting system 2 may be sent for further processing or solids separation, which is not shown here. The solids content and volume of the treated water 119 may be the same as or slightly higher than the contaminated steam feed stream 100.

[0050] System 2 takes in biologically contaminated water stream 100 and preheats it in preheat exchanger 101 using thermal treatment water stream 118 as a heat source. This helps recover heat from system 2 and improve the efficiency of system 2, thus reducing the energy costs associated with system 2. The preheated biologically contaminated water stream 102 then joins recycle stream 106.

[0051] The circulation of the contaminated water in the circulation stream 106 will now be described, starting with the flash vessel 103 shown in Figure 2. The liquid at the bottom of the flash vessel 103 leaves the flash vessel and is drawn into the circulation pump 105 via line 104. Unlike the system 1 shown in Figure 1, compressed steam provided by the blower 113 is injected through line 214 into the main circulation stream 106 via steam sparger 215A in line 104 to further heat the main circulation stream 106 in portion 104A. The portion 104A of the main circulation stream is then sent to the circulation pump 105.

[0052] The circulation pump 105 is operable to increase the pressure of the contaminated water in the circulation stream 106. For example, the circulation pump 105 may increase the pressure of the circulation stream 106 from 15 PSIG to 100 PSIG. The flow rate through the circulation pump 105 may be, for example, 5-400 times the flow rate of the biologically contaminated water supply 100. The circulation pump 105 discharges into the circulation stream 106. The main circulation stream 106 then branches into a portion 106A of the main circulation stream 106 and a thermally treated water stream 118 which then enters the heat exchanger 101 and exits the system 1 as treated water stream 119 as described above.

[0053] The circulation pump 105 may be a centrifugal positive displacement pump, a diaphragm pump, or other type of pump. The preheated contaminated water supply 102 is combined with the portion 106A of the main circulation flow 106 to form the portion 106B of the main circulation flow 106. Make-up steam 116 may be introduced into the main circulation 106B via a steam sparger 117 to provide supplemental heat to the portion 106C of the circulation flow 106. Make-up steam 116 may be provided from an external source to add thermal energy to the system 1.

[0054] The steam spargers 215A and 117 may be perforated pipes, eductors, or other devices capable of mixing steam and liquid in the pipes. The heated portion 106D of the main circulation stream 106 may then be forced through the pressure reduction device 107 to form steam in the portion 106E of the circulation stream 106, which may then be introduced into the flash sparger 108 in the flash vessel 103 where the steam and liquid are separated. The pressure reduction device 107 may be an orifice plate, a valve, or other device that creates a pressure reduction. The pressure reduction device 107 is where much of the cell lysis can occur due to the change from high temperature and high pressure to low pressure. The temperature in the main circulation stream 106 may range from 150 degrees to 300 degrees Fahrenheit, which is sufficient to destroy all pathogens introduced into the system 1 via the biologically contaminated water stream 100.

[0055] To increase efficiency, vapor from the flash vessel 103 may be captured and directed through line 109 into a mist eliminator 110 where the mist is separated from the vapor. Liquid recovered from the mist eliminator 110 may be directed through line 111 and reintroduced into the flash vessel 103. Dry vapor from the mist eliminator 110 may be directed through line 112 and compressed in a blower 113. For example, the pressure at the outlet of the blower 113 may be between 5 PSIG and 30 PSIG. The blower 113 may be a rotating lobe, fan, centrifugal, or other type of compressor. The compressed vapor from the blower 113 is then directed through line 214 and reintroduced into the main circulation 106 via a steam sparger 215A as described above. This process of capturing and reintroducing vapor helps recover latent heat in the system 2 to increase the overall efficiency.

[0056] As mentioned above, the hot treated water 118 from the main circulation 106 is separated from the circulation line 106 and directed to the preheater 101 which cools the treated water discharge stream 119 while heating the biologically contaminated water feed 119. The preheater 101 may be a plate and frame, spiral, shell and tube, or other type of heat exchanger.

[0057] FIG. 3 is a schematic block diagram illustrating another embodiment of a system for providing water treatment services. System 3 shown in FIG. 3 is similar to FIG. 1 and FIG. 2, with like parts labeled with like identifiers. System 3 is operable to treat contaminated water by dissolving cell walls, which facilitates filtration of the water, thus minimizing solids that are discarded. System 3 is further operable to destroy dangerous pathogens by temperature and residence time in accordance with EPA specifications, further contributing to ease disposal of solids.

[0058] The system 3 can include a biologically contaminated water feed stream 100 entering the system 3 and a treated water stream 119 exiting the system 3. The biologically contaminated water feed stream 100 can come from any upstream device or process that generates contaminated water, such as, but not limited to, waste activated sludge digesters, filters, centrifuges, hospitals, pharmaceutical manufacturing, food plants, etc. Also, the contaminated water stream 100 can contain 0%-30% solids. The treated water 119 exiting the system 3 can be sent for further processing or solids separation, which is not shown here. The solids content and volume of the treated water 119 can be the same as or slightly higher than the contaminated steam feed stream 100.

[0059] System 3 takes in biologically contaminated water stream 100 and preheats it in preheat exchanger 101 using thermal treatment water stream 118 as a heat source. This helps recover heat from system 3 and improve the efficiency of system 3, thus reducing the energy costs associated with system 3. The preheated biologically contaminated water stream 102 then joins recycle stream 106.

[0060] The circulation of the contaminated water in the circulation stream 106 will now be described, beginning with the flash vessel 103 shown in Figure 3. Liquid at the bottom of the flash vessel 103 leaves the flash vessel 103 and is drawn into the circulation pump 105 via line 104.

[0061] The circulation pump 105 is operable to increase the pressure of the contaminated water in the circulation stream 106. For example, the circulation pump 105 may increase the pressure of the circulation stream 106 from 15 PSIG to 100 PSIG. The flow rate through the circulation pump 105 may be, for example, 5-400 times the flow rate of the biologically contaminated water supply 100. The circulation pump 105 discharges into the circulation stream 106. The main circulation stream 106 then branches into a portion 106A of the main circulation stream 106 and a thermally treated water stream 118 which then enters the heat exchanger 101 and exits the system 1 as treated water stream 119 as described above.

[0062] The circulation pump 105 may be a centrifugal pump, a positive displacement pump, a diaphragm pump, or other type of pump. The preheated contaminated water supply 102 merges with portion 106A of the main circulation flow 106 to form portion 106B of the main circulation flow 106.

[0063] 3, portion 106B of the circulating flow 106 may be directed into a heat exchanger 321. The heat exchanger has a heat input 316 that is taken from an external source to provide heat to the heat exchanger 321. A return line 322 is provided that exits the heat exchanger 321. In some embodiments, the heat input 316 and return line 322 may be part of a closed loop fluid flow that provides heat to the system 3 from an external source. The heat exchanger 321 adds thermal energy to the main circulating flow 106 that exits the heat exchanger 321 at portion 106C of the main circulating flow.

[0064] Compressed steam 114 from blower 113 can be injected into main circulation stream 106 in portion 106C via steam sparger 115 to further heat main circulation stream 106 in portion 106D. Steam sparger 115 can be a perforated pipe, an eductor, or other device capable of mixing steam and liquid in a pipe. The heated portion 106D of main circulation stream 106 can then be forced through pressure let down device 107 to form steam in portion 106E of circulation stream 106, which can then be introduced to flash sparger 108 in flash vessel 103 where the steam and liquid are separated. Pressure let down device 107 can be an orifice plate, a valve, or other device that creates a pressure let down. Pressure let down device 107 is where much of the cell lysis can occur due to the change from high temperature and high pressure to low pressure. The temperature in the main circulation flow 106 may be in the range of 150°F to 300°F, which is sufficient to destroy any pathogens introduced into the system 1 via the biologically contaminated water flow 100.

[0065] In some embodiments, a pressure increase in the circulating stream can induce or cause lysis of the cellular microorganisms (e.g., bacteria). In other embodiments, a pressure drop or change in the circulating stream can induce or cause lysis of the cellular microorganisms. In yet other embodiments, heat applied to the circulating stream can induce or cause lysis of the cellular microorganisms. In further embodiments, a combination of two or more of the above (e.g., a pressure increase, a pressure drop, or temperature) can induce or cause lysis of the cellular microorganisms in the circulating stream. In some embodiments, one or more of these conditions (e.g., any individual, any combination of two, or a combination of all three) can be sufficient for 5%-100% of the cellular microorganisms in the circulating stream. In other embodiments, one or more of these conditions or events can be sufficient to lyse 20%-100% of the cellular microorganisms in the circulating stream. In other embodiments, the amount of lysed cellular microorganisms can be greater than 50%, 60%, 70%, 80%, 90%, or 95%. In some embodiments, one or more of these conditions or events may kill, destroy, or otherwise inactivate (e.g., by denaturation, etc.) other non-cellular pathogens in the circulating stream, such as viruses and other nucleic acid material. As previously discussed, lysis of cellular material, including cellular microorganisms, and release of liquids (such as water) and other internal materials significantly reduces the solids discharged by the system, allowing for further recovery or repurposing of the water.

[0066] To increase efficiency, vapor from the flash vessel 103 may be captured and directed through line 109 into a mist eliminator 110 where the mist is separated from the vapor. Liquid recovered from the mist eliminator 110 may be directed through line 111 and reintroduced into the flash vessel 103. Dry vapor from the mist eliminator 110 may be directed through line 112 and compressed in a blower 113. For example, the pressure at the outlet of the blower 113 may be between 5 PSIG and 30 PSIG. The blower 113 may be a rotating lobe, fan, centrifugal, or other type of compressor. The compressed vapor from the blower 113 is directed through line 114 and reintroduced into the main circulation flow 106 in portion 106C via a steam sparger 115 as described above. This process of capturing and reintroducing vapor helps recover latent heat in the system 1 to increase the overall efficiency.

[0067] As mentioned above, the hot treated water 118 from the main circulation 106 is separated from the circulation line 106 and directed to the preheater 101 which cools the treated water discharge stream 119 while heating the biologically contaminated water feed 119. The preheater 101 may be a plate and frame, spiral, shell and tube, or other type of heat exchanger.

[0068] While the foregoing examples illustrate the principles of the present invention in one or more specific applications, it will be apparent to those skilled in the art that numerous modifications in form, use, and details of implementation may be made without the exercise of imagination and without departing from the principles and concepts of the present invention. Accordingly, it is not intended that the present invention be limited, except as by the scope of the claims which follow.

Claims

1. 1. A system for treating a biologically contaminated water stream, comprising: a flash vessel configured to receive the biologically contaminated water stream and separate vapor from liquid in the biologically contaminated water stream; a blower configured to receive the separated vapor from the flash vessel and compress the separated vapor for reintroduction into the biologically-contaminated water stream; a circulation pump configured to receive the separated liquid from the flash vessel and pressurize the separated liquid into a circulation stream; a preheat exchanger configured to receive treated water from the circulating stream and to preheat the biologically contaminated water stream; a pressure reduction device configured to reduce the pressure of the biologically-contaminated water stream prior to receipt by the flash vessel; A system having

2. 10. The system of claim 1, further comprising a mist separator disposed between the flash vessel and the blower, the mist separator operable to extract liquid from the separated vapor.

3. 2. The system of claim 1, wherein the biologically contaminated water stream joins the circulating stream between the circulating pump and the pressure drop device.

4. 4. The system of claim 3, wherein the treated water is separated from the circulating stream between the pump and the confluence of the circulating stream with the biologically contaminated water stream.

5. 10. The system of claim 1, further comprising a heat exchanger operable to further heat the biological water stream before the physiologically contaminated water stream is directed to the pressure drop device.

6. 10. The system of claim 1, wherein the circulating pump pressurizes the circulating flow to a pressure sufficient to lyse at least a portion of microcellular organisms in the circulating flow.

7. 1. A system for treating a biologically contaminated water stream, comprising: a heat source configured to add heat to a circulating stream having a biologically contaminated water stream containing microorganisms and solids; a flash vessel configured to receive the recycle stream and separate vapor from liquid therefrom; a blower configured to receive the separated vapor from the flash vessel, compress the separated vapor, and reintroduce the separated vapor into the circulating stream to recover latent heat of vaporization; a circulation pump configured to receive the separated liquid from the flash vessel and pressurize the separated liquid into the circulation stream; a pressure reduction device configured to reduce the pressure of the circulating stream before the flash vessel receives the circulating stream, the pressure reduction device and the circulating pump causing disruption of cell walls of microorganisms in the circulating stream; a preheat exchanger configured to receive treated water from the circulation flow and recover heat from the treated water by preheating an inlet water to be added to the circulation flow; A system having

8. 7. The system of claim 6, further comprising a mist separator disposed between the flash vessel and the blower, the mist separator operable to extract liquid from the separated vapor.

9. The system of claim 6 , wherein the heat source is a heat exchanger.

10. The system of claim 6 , wherein the heat source comprises adding make-up steam to the circulating stream.

11. 7. The system of claim 6, wherein the separated vapor is reintroduced into the circulation stream between the flash vessel and the circulation pump.

12. 1. A method for recovering water from microorganisms in a biologically contaminated water stream, comprising: preheating the biologically-contaminated water stream using heat from the treated water stream; adding said preheated biologically contaminated water stream to a circulation stream; pressurizing and heating the circulating stream; reducing the pressure of the circulating stream; separating vapor from liquid in said circulating stream; compressing the vapor and reintroducing the vapor into the circulation stream; Discharging the treated water stream from the circulation stream. The method according to claim 1,

13. 12. The method of claim 11, wherein the recycle stream is pressurized between separating the vapor from the liquid and adding the preheated biologically-contaminated water stream to the recycle stream.

14. 12. The method of claim 11, further comprising the step of adding additional heat to said circulating stream after adding said pre-heated biologically contaminated water stream to said circulating stream.

15. 12. The method of claim 11 further comprising the steps of extracting a liquid stream from the vapor prior to compressing the vapor and adding the liquid stream to the circulation stream.

16. 12. The method of claim 11, wherein the steam is reintroduced into the recycle stream prior to pressurizing the recycle stream.

17. 1. A method for maximizing water recovery from a biologically contaminated water stream, comprising: lysing microcellular organisms in said contaminated water stream using pressure, or heat, or a combination thereof.

18. 20. The method of claim 17, wherein the pressure is a pressure increase, a pressure decrease, or a combination thereof.

19. 20. The method of claim 18, wherein the pressure is a pressure increase and a pressure drop.

20. 20. The method of claim 17, wherein between 5% and 100% of the microcellular organisms in the contaminated water stream are lysed.

21. 20. The method of claim 17, wherein the microcellular organism comprises a bacterium.

22. 20. The method of claim 17, further comprising the step of inactivating any other undissolved pathogens in the water stream.

23. 1. A method for reducing the weight of solids obtained from a biologically contaminated water stream, comprising: lysing microcellular organisms in said water stream and releasing water therefrom; combining the released water with other water in the contaminated water stream; separating the solids from the water; The method according to claim 1, 24. The method of claim 23, wherein the lysing is performed using pressure or heat or a combination thereof.

24. 20. The method of claim 17, wherein the pressure is a pressure increase, a pressure decrease, or a combination thereof.

25. 20. The method of claim 18, wherein the pressure is a pressure increase and a pressure decrease.

26. 20. The method of claim 17, wherein between 5% and 100% of the microcellular organisms in the contaminated water stream are lysed.

Images