Low energy ejector desalination system

Abstract

Systems and methods for treating a raw wastewater feed stream using an array of ejectors and evaporators for maximum heat integration in a water treatment system. The array of ejectors works as a heat pump to increase the pressure and temperature of a two-phase distillate stream used, in part, to heat the raw wastewater feed stream. The systems and methods utilize heat from a liquid distillate stream and a concentrated liquid wastewater stream to pre-heat the raw wastewater feed stream and produce a liquid distillate product stream.

Description

LOW ENERGY EJECTOR DESALINATION SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application, U.S. Patent Nos. 11,097,203 and 11,607,622, and PCT Patent Application Serial Nos. PCT / US20 / 21906 and PCT / US22 / 44590, which are incorporated herein by reference, are commonly assigned to Bechtel Energy Technologies & Solutions, Inc.FIELD OF THE DISCLOSURE

[0002] The present disclosure generally relates to treatment and desalination of seawater, produced water, and other high salinity water; it also has applicability to treatment of nuclear wastewater and other treatment processes requiring evaporator-based treatment. More particularly, the present disclosure relates to use of a low energy ejector desalination system (LEEDS), employing an array of ejectors and evaporators for maximum heat integration in a water treatment system.BACKGROUND

[0003] Thermal desalination processes that use steam as a heating medium typically use a vapor conditioning system to extract heat from the available steam through heat transfer. When these processes use vapor compression, either thermal or mechanical, they typically require auxiliary steam for start-up and to enhance normal operations.

[0004] The auxiliary steam for start-up and to enhance normal operations generally requires a fossil-fuel fired boiler to make the steam. The boiler for the auxiliary steam will usually require an air emissions permit to address emissions from fossil fuel combustion, which can include carbon monoxide, nitrogen oxides, and carbon dioxide. Permitting the boiler can be a challenge for facilities that do not normally produce steam (such as LNG) or facilities in environmentally sensitive areas or in other areas where air emission permits are difficult to obtain.Eliminating the need for the boiler has the further advantage of avoiding combustion of the boiler fuel and the associated emissions.BRIEF DESCRIPTION OF THE DRAWING

[0005] The present disclosure is described below with reference to the accompanying drawing, in which like elements are referenced with like numerals, and in which:

[0006] FIG. 1 is a schematic diagram illustrating one embodiment of a LEEDS system according to the present disclosure.DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

[0007] The subject matter of the present disclosure is described with specificity, however, the description itself is not intended to limit the scope of the disclosure. The subject matter thus, might also be embodied in other ways, to include different structures, steps and / or combinations similar to and / or fewer than those described herein, in conjunction with other present or future technologies. Although the term "step" may be used herein to describe different elements of methods employed, the term should not be interpreted as implying any particular order among or between various steps herein disclosed unless otherwise expressly limited by the description to a particular order. Other features and advantages of the disclosed embodiments will be or will become apparent to one of ordinary skill in the art upon examination of the following figure and detailed description. It is intended that all such additional features and advantages be included within the scope of the disclosed embodiments. Further, the illustrated figure is only exemplary and is not intended to assert or imply any limitation with regard to the environment, architecture, design, or process in which different embodiments may be implemented. All streams described are carried by physical lines. To the extent that temperatures and pressures are referenced in the following description, those conditions are merely illustrative and are not meant to limit the disclosure. For convenience, the components identified in FIG. 1 are listed below:

[0008] The present disclosure overcomes one or more deficiencies in the prior art by providing systems and methods for treatment and desalination of wastewater that does not require auxiliary steam during start-up or to enhance normal operations, thus eliminating the need to use (and obtain an air emissions permit for) a boiler for the auxiliary steam. The ability to treat high salt content wastewater without requiring steam augmentation is a primary feature that sets the system apart from conventional systems. This feature is principally accomplished by an array of ejectors and evaporators for maximum heat integration in the water treatment system.

[0009] In one embodiment, the present disclosure includes a system for treating raw wastewater, comprising: i) a plurality of heat exchangers to heat a respective mixed aqueous feed stream containing raw wastewater and create a respective two-phase stream; ii) a plurality of columns, wherein each column is in fluid communication with a respective one of the plurality of heat exchangers for separating the respective two-phase stream into a vapor distillate stream and a concentrated liquid wastewater stream; iii) a plurality of ejectors, wherein each ejector is in fluid communication with at least two of the plurality of columns for combining the vapor distillate stream from one of the plurality of columns and a liquid distillate stream from another one of the plurality of columns to produce an ejector two-phase stream; iv) a separator in fluid communication with the plurality of ejectors for separating the ejector two-phase stream into another vapor distillate stream and the liquid distillate stream, wherein the vapor distillate stream from the another one of the plurality of columns and the another vapor distillate stream are in fluidcommunication; and v) wherein the vapor distillate stream from each column except the one of the plurality of columns is fluidly connected to an adjacent one of the plurality of columns for heating the mixed aqueous feed stream in the adjacent one of the plurality of columns with a respective heat exchanger.

[0010] In another embodiment, the present disclosure includes a method for treating raw wastewater, comprising: i) heating a plurality of mixed aqueous feed streams containing raw wastewater in a respective heat exchanger to create a plurality of respective two-phase streams; ii) separating each two-phase stream in a respective column into a vapor distillate stream and a concentrated liquid wastewater stream; iii) combining the vapor distillate stream from one column and a liquid distillate stream from another column in a plurality of ejectors to produce another two- phase stream; iv) separating the another two-phase stream in the another column into another vapor distillate stream and the liquid distillate stream, wherein the another vapor distillate stream and the vapor distillate stream from the another column are in fluid communication; and v) using the vapor distillate stream from each column except the one column to heat one of the plurality of mixed aqueous feed streams in an adjacent column with the respective heat exchanger.

[0011] Referring now to FIG 1, the system 100 is a low energy ejector desalination system for processing a pre-treated or pre-conditioned raw wastewater feed stream 102, which may comprise aqueous feed streams with or without saline water and / or a high concentration of suspended and / or dissolved solids. The pre-treatment or pre-conditioning of the raw wastewater feed stream 102 minimizes scaling and corrosion in the heat exchangers and other associated equipment. The pre-treatment or pre-conditioning may include chemical precipitation, coagulation, and flocculation, softening by precipitation and ion exchange, addition of anti-scalantand anti-corrosion chemicals, pH adjustment, and other means to prevent scaling and corrosion in the associated equipment.

[0012] The raw wastewater feed stream 102 is sent to a heat exchanger system 104 where heat is transferred from a distillate product steam 106 and a concentrated wastewater product stream 108 to the raw wastewater feed stream 102 to produce a heated raw wastewater feed stream 102. The heat exchanger system 104 may include two or more heat exchangers arranged in series (as shown) or in parallel. The heated raw wastewater feed stream 102 is mixed with a first concentrated liquid wastewater stream 112a exiting an outlet in the bottom of a first column 122a to produce a first mixed aqueous feed stream 114a that may be pumped, partially, through to a first falling film heat exchanger 116a positioned in the first column 122a using a first column pump 126a. Another portion of the first mixed aqueous feed stream 114a may also be mixed with a second concentrated liquid wastewater stream 112b exiting an outlet in the bottom of a second column 122b to produce a second mixed aqueous feed stream 114b as shown. Alternatively, a portion of the first concentrated liquid wastewater stream 112a may be mixed with the second concentrated liquid wastewater stream 112b exiting the outlet in the bottom of the second column 122b to produce the second mixed aqueous feed stream 114b while another portion of the first concentrated liquid wastewater stream 112a is mixed with the heated raw wastewater feed stream 102 to produce the first mixed aqueous feed stream 114a.

[0013] The first mixed aqueous feed stream 114a is distributed through the first falling film heat exchanger 116a, which heats the first mixed aqueous feed stream 114a and creates a two- phase mixed aqueous feed stream. A hot vapor distillate is separated from the two-phase mixed aqueous feed stream in the first column 122a after it leaves the first falling film heat exchanger 116a. The hot vapor distillate collects above the first falling film heat exchanger 116a in the firstcolumn 122a and exits an outlet in the top of the first column 122a as a first column hot vapor distillate stream 132a. Concentrated liquid wastewater, which may include brine, is separated from the two-phase mixed aqueous feed stream in the first column 122a after the hot vapor distillate leaves the first falling film heat exchanger 116a. The concentrated liquid wastewater collects below the first falling film heat exchanger 116a in the first column 122a and exits an outlet in the bottom of the first column 122a as the first concentrated liquid wastewater stream 112a.

[0014] The first column hot vapor distillate stream 132a is drawn into a first ejector 134a by suction, where it is mixed with and compressed by a high- temperature fourth column liquid distillate stream 142d, which functions as a motive fluid. Optionally, the first column hot vapor distillate stream 132a may be drawn into multiple ejectors 134a, 134b, 134c, 134d by suction through an ejector manifold, where it is mixed with and compressed by the fourth column liquid distillate stream 142d. Preferably, each ejector 134a-134d is a static liquid-gas ejector (with no moving parts). The first ejector 134a (and optionally each ejector) produces a two-phase distillate stream 136, which is at a temperature slightly higher than that of the first column hot vapor distillate stream 132a. The two-phase distillate stream 136 is ejected into a separator 137. The separator 137 separates the two-phase distillate stream 136 into the fourth column liquid distillate stream 142d and a separated hot vapor distillate stream 146.

[0015] The separated hot vapor distillate stream 146 enters a hot side inlet of a fourth falling film heat exchanger 116d and rises upward through individual heating elements, which heats a fourth mixed aqueous feed stream 114d distributed downward through the fourth falling film heat exchanger 116d between the individual heating elements and creates a two-phase mixed aqueous feed stream. A hot vapor distillate is separated from the two-phase mixed aqueous feed stream in the fourth column 122d after it leaves the fourth falling film heat exchanger 116d. Theseparated hot vapor distillate stream 146 combines with the hot vapor distillate that collects above the fourth falling film heat exchanger 116d and exits an outlet in the top of the fourth column 122d as another fourth column hot vapor distillate stream 132d. The fourth column liquid distillate stream 142d falls downward through the individual heating elements of the fourth falling film heat exchanger 116d and exits an outlet near the bottom of the fourth column 122d. The fourth column liquid distillate stream 142d is then sent to a distillate tank 138 where it is collected and heated during start-up operations.

[0016] Concentrated liquid wastewater, which may include brine, is separated from the two-phase mixed aqueous feed stream in the fourth column 122d after the hot vapor distillate leaves the fourth falling film heat exchanger 116d. The concentrated liquid wastewater collects below the fourth falling film heat exchanger 116d in the fourth column 122d and exits an outlet in the bottom of the fourth column 122d as the fourth concentrated liquid wastewater stream 112d. A portion of a third mixed aqueous feed stream 114c is mixed with the fourth concentrated liquid wastewater stream 112d exiting the outlet in the bottom of a fourth column 122d to produce the fourth mixed aqueous feed stream 114d that may be, partially, pumped through to the fourth falling film heat exchanger 116d using a fourth column pump 126d. Another portion of the fourth mixed aqueous feed stream 114d may be sent to a brine flash tank 154, which produces the concentrated wastewater product stream 108 and a brine flash tank vapor distillate stream 156 that is sent to the third column 122c. Alternatively, a portion of the fourth concentrated liquid wastewater stream 112d may be sent through the heat exchanger system 104 as the concentrated wastewater product stream 108 while another portion of the fourth concentrated liquid wastewater stream 112d is mixed with the third mixed aqueous feed stream 114c to produce the fourth mixed aqueous feed stream 114d.

[0017] A portion of the fourth column liquid distillate stream 142d exits an outlet in the bottom of the distillate tank 138 and is pumped through to the first ejector 134a (and optionally each ejector through an ejector manifold), using a distillate tank pump 140. Optionally, a separate distillate tank pump may be used for each ejector (instead of an ejector manifold) when multiple ejectors are used. Another portion of the fourth column liquid distillate stream 142d may be sent from the distillate tank 138, once it meets a predetermined temperature and level, to a first distillate flash tank 148a where it is separated into a first flashed vapor distillate stream 150a and a first flashed liquid distillate stream 152a. Alternatively, a portion of the fourth column liquid distillate stream 142d may be sent from the distillate tank 138 through the heat exchanger system 104 as the distillate product steam 106.

[0018] The another fourth column hot vapor distillate stream 132d may be combined with the first flashed vapor distillate stream 150a to form a first combined vapor distillate stream 158a. The first combined vapor distillate stream 158a or, alternatively, the another fourth column hot vapor distillate stream 132d enters a hot side inlet of a third falling film heat exchanger 116c and rises upward through individual heating elements, which heats a third mixed aqueous feed stream 114c distributed downward through the third falling film heat exchanger 116c between the individual heating elements and creates a two-phase mixed aqueous feed stream. A hot vapor distillate is separated from the two-phase mixed aqueous feed stream in the third column 122c after it leaves the third falling film heat exchanger 116c. The first combined vapor distillate stream 158a or, alternatively, the another fourth column hot vapor distillate stream 132d combines with the hot vapor distillate that collects above the third falling film heat exchanger 116c and exits an outlet in the top of the third column 122c as a third column hot vapor distillate stream 132c. A third column liquid distillate stream 142c is formed from condensation and falls downward throughthe individual heating elements of the third falling film heat exchanger 116c and exits an outlet near the bottom of the third column 122c. The third column liquid distillate stream 142c is then combined with the first flashed liquid distillate stream 152a to form a first combined liquid distillate stream 160a, which is sent to a second distillate flash tank 148b where it is separated into a second flashed vapor distillate stream 150b and a second flashed liquid distillate stream 152b. Alternatively, the third column liquid distillate stream 142c may be sent to the distillate tank 138 where it is collected and heated during start-up operations.

[0019] Concentrated liquid wastewater, which may include brine, is separated from the two-phase mixed aqueous feed stream in the third column 122c after the hot vapor distillate leaves the third falling film heat exchanger 116c. The concentrated liquid wastewater collects below the third falling film heat exchanger 116c in the third column 122c and exits an outlet in the bottom of the third column 122c as a third concentrated liquid wastewater stream 112c. A portion of a second mixed aqueous feed stream 114b is mixed with the third concentrated liquid wastewater stream 112c exiting the outlet in the bottom of a third column 122c to produce the third mixed aqueous feed stream 114c that may be, partially, pumped through to the third falling film heat exchanger 116c using a third column pump 126c. Another portion of the third mixed aqueous feed stream 114c may also be mixed with the fourth concentrated liquid wastewater stream 112d exiting an outlet in the bottom of the fourth column 122d to produce the fourth mixed aqueous feed stream 114d as shown. Alternatively, a portion of the third concentrated liquid wastewater stream 112c may be mixed with a portion of the second mixed aqueous feed stream 114b to produce the third mixed aqueous feed stream 114c while another portion of the third concentrated liquid wastewater stream 112c is mixed with the fourth concentrated liquid wastewater stream 112d to produce the fourth mixed aqueous feed stream 114d.

[0020] The third column hot vapor distillate stream 132c may be combined with the second flashed vapor distillate stream 150b to form a second combined vapor distillate stream 158b. The second combined vapor distillate stream 158b or, alternatively, the third column hot vapor distillate stream 132c enters a hot side inlet of a second falling film heat exchanger 116b and rises upward through individual heating elements, which heats the second mixed aqueous feed stream 114b distributed downward through the second falling film heat exchanger 116b between the individual heating elements and creates a two-phase mixed aqueous feed stream. A hot vapor distillate is separated from the two-phase mixed aqueous feed stream in the second column 122b after it leaves the second falling film heat exchanger 116b. The second combined vapor distillate stream 158b or, alternatively, the third column hot vapor distillate stream 132c combines with the hot vapor distillate that collects above the second falling film heat exchanger 116b and exits an outlet in the top of the second column 122b as a second column hot vapor distillate stream 132b. A second column liquid distillate stream 142b is formed from condensation and falls downward through the individual heating elements of the second falling film heat exchanger 116b and exits an outlet near the bottom of the second column 122b. The second column liquid distillate stream 142b is then combined with the second flashed liquid distillate stream 152b to form a second combined liquid distillate stream 160b, which is sent to a third distillate flash tank 148c where it is separated into a third flashed vapor distillate stream 150c and a third flashed liquid distillate stream 152c. Alternatively, the second column liquid distillate stream 142b may be sent to the distillate tank 138 where it is collected and heated during start-up operations.

[0021] Concentrated liquid wastewater, which may include brine, is separated from the two-phase mixed aqueous feed stream in the second column 122b after the hot vapor distillate leaves the second falling film heat exchanger 116b. The concentrated liquid wastewater collectsbelow the second falling film heat exchanger 116b in the second column 122b and exits an outlet in the bottom of the second column 122b as the second concentrated liquid wastewater stream 112b. A portion of the first mixed aqueous feed stream 114a is mixed with the second concentrated liquid wastewater stream 112b exiting the outlet in the bottom of a second column 122b to produce the second mixed aqueous feed stream 114b that may be, partially, pumped through to the second falling film heat exchanger 116b using a second column pump 126b. Another portion of the second mixed aqueous feed stream 114b may also be mixed with the third concentrated liquid wastewater stream 112c exiting an outlet in the bottom of the third column 122c to produce the third mixed aqueous feed stream 114c as shown. Alternatively, a portion of the second concentrated liquid wastewater stream 112b may be mixed with a portion of the first mixed aqueous feed stream 114a to produce the second mixed aqueous feed stream 114b while another portion of the second concentrated liquid wastewater stream 112b is mixed with the third concentrated liquid wastewater stream 112c to produce the third mixed aqueous feed stream 114c.

[0022] The second column hot vapor distillate stream 132b may be combined with the third flashed vapor distillate stream 150c to form a third combined vapor distillate stream 158c. The third combined vapor distillate stream 158c or, alternatively, the second column hot vapor distillate stream 132b enters a hot side inlet of a first falling film heat exchanger 116a and rises upward through individual heating elements, which heats the first mixed aqueous feed stream 114a distributed downward through the first falling film heat exchanger 116a between the individual heating elements and creates the two-phase mixed aqueous feed stream. The third combined vapor distillate stream 158c or, alternatively, the second column hot vapor distillate stream 132b combines with the hot vapor distillate that collects above the first falling film heat exchanger 116a and exits the outlet in the top of the first column 122a as the first column hot vapor distillate stream132a. A first column liquid distillate stream 142a is formed from condensation and falls downward through the individual heating elements of the first falling film heat exchanger 116a and exits an outlet near the bottom of the first column 122a. The first column liquid distillate stream 142a is then combined with the third flashed liquid distillate stream 152c to form a third combined liquid distillate stream 160c, which is sent to a fourth distillate flash tank 148d where it is separated into a fourth flashed vapor distillate stream 150d and the distillate product steam 106. Alternatively, the first column liquid distillate stream 142a may be sent to the distillate tank 138 where it is collected and heated during start-up operations.

[0023] Concentrated liquid wastewater, which may include brine, is separated from the two-phase mixed aqueous feed stream in the first column 122a after the hot vapor distillate leaves the first falling film heat exchanger 116a. The concentrated liquid wastewater collects below the first falling film heat exchanger 116a in the first column 122a and exits an outlet in the bottom of the first column 122a as the first concentrated liquid wastewater stream 112a.

[0024] The system 100 is unique, simple, and environmentally safe. The system 100 is made more efficient by using an array of ejectors and evaporators for maximum heat integration in the system 100. The system 100 further yields a value-added distillate product stream 106 and concentrated wastewater product stream 108. Compared to a similar system using a single evaporator and a single ejector, the system 100 can produce the largest temperature differential (2x) and compression ratio (Cr=3.52) when operating in a vacuum condition of 5psia. The system 100 thus lowers energy requirements for evaporation, reduces the evaporator size and lowers operating temperatures, which improves the evaporator lifespan.

[0025] While the present disclosure has been described in connection with presently preferred embodiments, it will be understood by those skilled in the art that it is not intended tolimit the disclosure in those embodiments. For example, the system 100 may be modified to include additional ejectors, evaporators and related components to address the specific needs of a particular project. In addition, the system 100 can be applied to treat other aqueous streams with a high concentration of suspended solids such as the production of high quality distilled or demineralized water, the reduction of volume of aqueous streams, and the recovery of products where evaporation is employed. It is therefore contemplated that various alternative embodiments and modifications may be made to the disclosed embodiments without departing from the spirit and scope of the appended claims and equivalents thereof.

Claims

CLAIMS1. A system for treating raw wastewater, comprising: a plurality of heat exchangers to heat a respective mixed aqueous feed stream containing raw wastewater and create a respective two-phase stream; a plurality of columns, wherein each column is in fluid communication with a respective one of the plurality of heat exchangers for separating the respective two-phase stream into a vapor distillate stream and a concentrated liquid wastewater stream; a plurality of ejectors, wherein each ejector is in fluid communication with at least two of the plurality of columns for combining the vapor distillate stream from one of the plurality of columns and a liquid distillate stream from another one of the plurality of columns to produce an ejector two-phase stream; a separator in fluid communication with the plurality of ejectors for separating the ejector two-phase stream into another vapor distillate stream and the liquid distillate stream, wherein the vapor distillate stream from the another one of the plurality of columns and the another vapor distillate stream are in fluid communication; and wherein the vapor distillate stream from each column except the one of the plurality of columns is fluidly connected to an adjacent one of the plurality of columns for heating the mixed aqueous feed stream in the adjacent one of the plurality of columns with a respective heat exchanger.

2. The system of claim 1, wherein the another one of the plurality of columns encloses the separator.

3. The system of claim 2, wherein each column is fluidly connected to one of the liquid distillate stream and a respective another liquid distillate stream.

4. The system of claim 3, further comprising: a distillate tank in fluid communication with the liquid distillate stream and each respective another liquid distillate stream; and a pump fluidly connecting the distillate tank to the plurality of ejectors.

5. The system of claim 3, further comprising: a distillate tank in fluid communication with the liquid distillate stream; and a pump fluidly connecting the distillate tank to the plurality of ejectors.

6. The system of claim 5, further comprising: a plurality of distillate flash tanks wherein at least one of the plurality of distillate flash tanks is fluidly connected to the distillate tank and each one of the plurality of distillate flash tanks is fluidly connected to an adjacent one of the plurality of distillate flash tanks.

7. The system of claim 6, wherein each one of the plurality of distillate flash tanks is positioned downstream of and in fluid communication with a respective one of the liquid distillate stream and the another liquid distillate stream.

8. The system of claim 7, wherein each one of the plurality of distillate flash tanks includes a flashed vapor distillate stream in fluid communication with one of a respective one of the plurality of columns and the plurality of ejectors.

9. The system of claim 2, further comprising: a raw wastewater feed stream in fluid communication with the concentrated liquid wastewater stream from the one of the plurality of columns.

10. The system of claim 9, wherein a portion of each mixed aqueous feed stream is fluidly connected to one of the concentrated liquid wastewater stream from an adjacent one of the plurality of columns and a brine flash tank.11 . The system of claim 10, wherein the brine flash tank is fluidly connected to a concentrated wastewater product stream and a brine flash tank vapor distillate stream.

12. A method for treating raw wastewater, comprising: heating a plurality of mixed aqueous feed streams containing raw wastewater in a respective heat exchanger to create a plurality of respective two-phase streams; separating each two-phase stream in a respective column into a vapor distillate stream and a concentrated liquid wastewater stream; combining the vapor distillate stream from one column and a liquid distillate stream from another column in a plurality of ejectors to produce another two-phase stream; separating the another two-phase stream in the another column into another vapor distillate stream and the liquid distillate stream, wherein the another vapor distillate stream and the vapor distillate stream from the another column are in fluid communication; and using the vapor distillate stream from each column except the one column to heat one of the plurality of mixed aqueous feed streams in an adjacent column with the respective heat exchanger.

13. The method of claim 12, wherein each column produces one of the liquid distillate stream and a respective another liquid distillate stream.

14. The method of claim 13, further comprising: sending the liquid distillate stream from the another column and each another liquid distillate stream to a distillate tank; and pumping a portion of the liquid distillate stream and each another liquid distillate stream from the distillate tank to the plurality of ejectors.

15. The method of claim 13, further comprising:sending the liquid distillate stream from the another column to a distillate tank; and pumping a portion of the liquid distillate stream from the distillate tank to the plurality of ejectors.

16. The method of claim 15, further comprising: sending another portion of the liquid distillate stream from the distillate tank to a distillate flash tank; and sending each another liquid distillate stream to a respective another distillate flash tank.

17. The method of claim 15, wherein the distillate flash tank and each another distillate flash tank are in fluid communication and produce a respective flashed vapor distillate stream in fluid communication with one of a respective column and the plurality of ejectors.

18. The method of claim 12, further comprising: mixing a raw wastewater feed stream and the concentrated liquid wastewater stream from the one column to produce one of the plurality of mixed aqueous feed streams.

19. The method of claim 18, further comprising: sending a portion of each mixed aqueous feed stream from a respective column to one of the concentrated liquid wastewater stream from an adjacent respective column and a brine flash tank.

20. The method of claim 19, wherein the brine flash tank is fluidly connected to a concentrated wastewater product stream and a brine flash tank vapor distillate stream.

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