Ammonia nitrogen recovery apparatus and system for recovering ammonia nitrogen using the same

Abstract

The present invention comprises: a first supply unit for supplying a first solution containing ammoniacal nitrogen; a second supply unit for supplying a second solution containing water; a third supply unit for supplying a third solution containing sodium sulfate; an oxidation electrode unit and a reduction electrode unit disposed at a predetermined distance from the oxidation electrode unit; and a plurality of unit cells comprising one or more cation exchange membranes, a bipolar membranes, and anion exchange membranes arranged sequentially to sequentially partition a first flow path fluidly connected to the first supply unit, a second flow path fluidly connected to the second supply unit, and a third flow path fluidly connected to the third supply unit, wherein the plurality of unit cells are arranged sequentially; and a membrane contact unit for producing an ammonium sulfate solution through contact between the ammonia gas contained in the first flow path discharge water and the sulfuric acid contained in the second flow path discharge water, wherein the first flow path discharge water discharged from the first flow path and the second flow path discharge water discharged from the second flow path are respectively supplied. The present invention provides an ammonia nitrogen recovery device comprising an ammonia gas conversion unit, wherein the ammonia gas conversion unit further comprises a solution supply unit separately provided to supply sulfuric acid contained in the second flow path discharge water to the membrane contact unit, and the second flow path discharge water is supplied to the membrane contact unit through the solution supply unit.

Description

Technology Field

[0001] The present invention relates to an ammonia nitrogen recovery device using electrodialysis to recover ammonia nitrogen contained in wastewater, etc., an ammonia nitrogen recovery system using the same, and a method for recovering ammonia nitrogen. Background Technology

[0002] Ammonia nitrogen (NH3, NH4) + ) is nitrogen that exists as ammonia or ammonium salts among various nitrogen compounds, and is important as an indicator of water pollution and is a factor in the eutrophication of water bodies.

[0003] To control such ammonia nitrogen, an ammonia stripping process is generally used. Ammonia stripping separates ammonia nitrogen from wastewater by raising the temperature of the wastewater, supplying a strong air supply, and using chemicals to raise the pH. However, this separation has the disadvantage of incurring high operating costs due to the use of alkaline chemicals to maintain a high pH (above 11).

[0004] In addition, while efficient recovery is possible in a short time, it has the disadvantage of lower efficiency when processing large volumes.

[0005] Accordingly, there is a need for technology to efficiently remove and recover ammoniacal nitrogen even at large volumes.

[0006] Meanwhile, if we examine the prior art Korean patent (10-2024-0146308), an ammonia nitrogen recovery device using an electrodialysis device is disclosed in which an ammonium sulfate solution discharged to a first discharge section (610) is supplied to a second supply section (120) and flowed into the stack.

[0007] Here, when the ammonium sulfate solution is supplied to the second flow path (420) inside the stack, sulfate ions (SO4 2- ) hydrogen ions (H) generated in the anode membrane +It combines with ) to form sulfuric acid (H2SO4).

[0008] At this time, the ammonium ions contained in the ammonium sulfate solution (, NH4 + There was a problem with leakage of ammonium ions passing through the anion exchange membrane (350) and moving to the third flow path.

[0009] Figure 9 shows ammoniacal nitrogen (NH3, NH4 + This is a graph showing experimental results that confirm the leakage state of ). Figure 9 (A) shows the results of checking the leakage of ammonia nitrogen according to the thickness of the ion exchange membrane, and it was confirmed that more leakage occurred as the thickness of the ion exchange membrane became thinner. Figure 9 (B) shows the results of checking the leakage of ammonia nitrogen according to the length of the stack, and it was confirmed that more leakage occurred as the length of the stack increased, i.e., as the fluid flow increased, i.e., the residence time increased.

[0010] Furthermore, when actual wastewater (e.g., anaerobic digestate) is supplied into the stack for a process to recover ammoniacal nitrogen, the pH in specific channels within the stack increases due to the ammoniacal nitrogen contained in the actual wastewater. At this time, due to the increased pH, calcium ions (Ca) contained in the actual wastewater 2+ There was a problem with precipitation. Calcium ions form as precipitates, causing scaling that impairs the performance of the ion exchange membrane.

[0011] Figure 10 is a photograph showing the condition of the waste liquid before and after the experiment, confirming the state in which calcium ions were precipitated. As shown in the photograph, the state in which calcium ions were precipitated after the experiment could be confirmed.

[0012] Figure 11 shows that as a result of checking the XRD peaks to confirm whether calcium ions were precipitated, Calcium Sulfate Hydrate (Ca(SO4)·(H2O)0.8) and Vaterite (CaCO3) were confirmed.

[0013] Accordingly, there is a need for technology to efficiently remove and recover ammoniacal nitrogen even at large volumes while preventing the leakage of ammonium ions and the precipitation of calcium ions. The problem to be solved

[0014] The purpose of the present invention is to provide an ammonia nitrogen recovery device using electrodialysis for recovering ammonia nitrogen contained in wastewater, etc.

[0015] In particular, the purpose is to provide an electrodialysis stack, an ammonia nitrogen recovery device using the same, and a nitrogen recovery system that prevents the leakage of ammonium ions and the precipitation of calcium ions, enables efficient processing even at large volumes, and minimizes contamination of the ion exchange membrane and electrodes placed inside. means of solving the problem

[0016] A first supply unit for supplying a first solution containing ammoniacal nitrogen; a second supply unit for supplying a second solution containing water; a third supply unit for supplying a third solution containing sodium sulfate; an oxidation electrode unit and a reduction electrode unit disposed at a predetermined distance from the oxidation electrode unit; and a plurality of unit cells comprising one or more cation exchange membranes, a positive membranes, and anion exchange membranes arranged sequentially to partition a first flow path fluidly connected to the first supply unit, a second flow path fluidly connected to the second supply unit, and a third flow path fluidly connected to the third supply unit, between the oxidation electrode unit and the reduction electrode unit, wherein the plurality of unit cells are arranged sequentially; and a membrane contact unit for producing an ammonium sulfate solution through contact between the ammonia gas contained in the first flow path discharge water and the sulfuric acid contained in the second flow path discharge water, wherein the first flow path discharge water discharged from the first flow path and the second flow path discharge water discharged from the second flow path are respectively supplied. The ammonia gas conversion unit includes a solution supply unit separately provided to supply sulfuric acid contained in the second flow path discharge water to the membrane contact unit, and the second flow path discharge water is supplied to the membrane contact unit through the solution supply unit, thereby providing an ammonia nitrogen recovery device.

[0017] Additionally, the ammonia nitrogen recovery device further comprises a control unit configured to control the flow of first to third solutions, first flow path discharge water, and second flow path discharge water, wherein the control unit comprises: a first operating mode for producing second flow path discharge water in an ammonia gas conversion unit; a second operating mode for treating ammonia nitrogen by contacting the first flow path discharge water and the second flow path discharge water in a membrane contact unit and producing an ammonium sulfate solution; and a third operating mode for adjusting the pH of the ammonia gas conversion unit, wherein the control unit controls the operation to select one or more of the first to third operating modes as needed.

[0018] Additionally, the first operating mode includes a concentration mode for concentrating the second flow path discharge water and a transfer mode for transferring the concentrated second flow path discharge water to a solution supply unit, and the control unit includes controlling to stop the operation of the concentration mode when the transfer mode is operated.

[0019] Additionally, the control unit controls the second flow path discharge water produced in the second operation mode and received in the second supply unit to be supplied to each of the first to third flow paths when operating in the third operation mode, and controls the pH-controlled discharge water discharged after passing through each of the first to third flow paths to be circulated to the second supply unit.

[0020] Additionally, the first supply unit includes a first line that is fluidly movably connected to one or more first flow paths, the second supply unit includes a second line that is fluidly movably connected to one or more second flow paths, the third supply unit includes a third line that is fluidly movably connected to one or more third flow paths, and may include a fourth line that fluidly movably connects the first flow path and the membrane contact part so that the first flow path discharge water discharged through each first flow path is supplied to the membrane contact part, and may include a fifth line that fluidly movably connects the second flow path and the second supply unit so that the second flow path discharge water discharged through each second flow path is re-supplied to the second supply unit, and may include a sixth line that fluidly movably connects the third flow path and the third supply unit so that the third flow path discharge water discharged through each third flow path is re-supplied to the third supply unit.

[0021] Additionally, the solution supply unit includes a seventh line fluidly connected to the second supply unit to supply the second flow path discharge water contained in the second supply unit to the solution supply unit, the solution supply unit includes an eighth line fluidly connected to the membrane contact unit to supply the second flow path discharge water to the membrane contact unit, and the solution supply unit may include a ninth line fluidly connected to the solution supply unit and the membrane contact unit to transfer the ammonium sulfate solution produced at the membrane contact unit to the solution supply unit.

[0022] In addition, the ammonia gas conversion unit described above; the one or more membrane contact units described above; and the control unit provided for controlling the flow of first to third solutions, first flow path discharge water, and second flow path discharge water, wherein the ammonia gas conversion unit includes first and second ammonia gas conversion units, and the membrane contact unit includes first to third membrane contact units, and the control unit includes a first operating mode for producing second flow path discharge water in the ammonia gas conversion unit; a second operating mode for treating ammonia nitrogen by contacting the first flow path discharge water and the second flow path discharge water in the membrane contact unit and producing an ammonium sulfate solution; and a third operating mode for adjusting the pH of the ammonia gas conversion unit, and the control unit controls the operation to select one or more of the first to third operating modes as needed.

[0023] Additionally, the control unit includes controlling the first and second ammonia gas conversion units to a selected control mode among the first to third operating modes so that they are simultaneously operated in the same operating mode or different operating modes as needed.

[0024] In addition, the control unit includes controlling the operation of a selected membrane contact part among the first to third membrane contact parts as needed.

[0025] In addition, the control unit controls the first ammonia gas conversion unit and the second ammonia gas conversion unit to operate alternately so that the ammonia nitrogen recovery system operates continuously. Effects of the invention

[0026] According to the present invention, ammoniacal nitrogen contained in wastewater, water, and sodium sulfate solution can be effectively recovered by efficiently arranging the flow paths of wastewater, water, and sodium sulfate solution.

[0027] In addition, the ammonia nitrogen recovery device according to the present invention can prevent leakage of ammonium ions and prevent membrane scaling caused by the precipitation of ions such as calcium.

[0028] In addition, it enables efficient processing even at high volumes, minimizes contamination of the internal ion exchange membranes and electrodes, and reduces operating costs by not using alkaline chemicals or sulfuric acid.

[0029] In addition, operating costs can be reduced by producing the acidic solution used in the stack during the CIP process (third operating mode) for cleaning the internal flow paths of the stack. Brief explanation of the drawing

[0030] FIGS. 1 and 2 are drawings illustrating an ammonia nitrogen recovery device using electrodialysis according to an embodiment of the present invention. FIGS. 3 and 4 are drawings illustrating a first operating mode of a nitrogen recovery device according to an embodiment of the present invention. FIG. 5 is a diagram illustrating a second operating mode of a nitrogen recovery device according to one embodiment of the present invention. FIG. 6 is a diagram illustrating a third operating mode of a nitrogen recovery device according to one embodiment of the present invention. FIG. 7 is a diagram illustrating a nitrogen recovery system using a nitrogen recovery device according to one embodiment of the present invention. Figure 8 is a graph showing the experimental results of a nitrogen recovery device according to one embodiment of the present invention. Figures 9 to 11 are graphs and photographs confirming the problems of ammoniacal nitrogen leakage and calcium ion precipitation of the prior art. Specific details for implementing the invention

[0031] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0032] Additionally, identical or corresponding components are assigned the same or similar reference numbers regardless of drawing symbols, and redundant descriptions thereof are omitted; furthermore, for the convenience of explanation, the size and shape of each illustrated component may be exaggerated or reduced.

[0033] Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0034] In addition, the phrase "connected through a line" in this document may mean that a fluid is connected using a flow path such as a pipe or piping to move.

[0035] Additionally, in this document, 'a ~part in which a solution is received' may refer to a storage tank or vessel capable of receiving a fluid or solution.

[0036] Additionally, for the sake of convenience of explanation, spacers, gaskets, etc., generally placed between each ion exchange membrane have been omitted in this document.

[0038] An ammonia nitrogen recovery device using electrodialysis according to one embodiment of the present invention (hereinafter also referred to as the 'ammonia nitrogen recovery device' or 'nitrogen recovery device') provides an ammonia nitrogen recovery device using an electrodialysis stack and a membrane contactor.

[0040] Hereinafter, with reference to the attached FIGS. 1 to 6, an ammoniacal nitrogen recovery device (10) according to one embodiment of the present invention and a nitrogen recovery system using the same will be described in detail.

[0041] FIGS. 1 and FIGS. 2 are drawings illustrating an ammonia nitrogen recovery device (10) according to the present invention.

[0042] Referring to FIGS. 1 and 2, an ammonia nitrogen recovery device (10) according to one embodiment of the present invention includes an ammonia gas conversion unit (100) and a membrane contact unit (500).

[0043] The above ammonia gas conversion unit (100) includes a first supply unit (110) that supplies a first solution containing ammoniacal nitrogen, a second supply unit (120) that supplies a second solution containing water, and a third supply unit (130) that supplies a third solution containing sodium sulfate.

[0044] Here, the first solution may be a solution containing ammoniacal nitrogen, for example, anaerobic digestion treated water containing ammoniacal nitrogen or wastewater containing ammoniacal nitrogen and a mixed solution containing one or more of these, but is not limited thereto, and any solution (fluid) containing ammoniacal nitrogen may be applied.

[0045] Additionally, the second solution may be a solution containing water, for example, water, a sulfuric acid solution produced in an ammonia gas conversion unit, a diluted sulfuric acid solution, and a mixed solution containing one or more of these.

[0046] Here, the second solution may preferably be a diluted sulfuric acid solution obtained by mixing water with a sulfuric acid solution, and using a diluted sulfuric acid solution has the advantage of lowering the energy consumption rate because the electrical resistance is lower than when using water.

[0047] In particular, the diluted sulfuric acid solution may use the sulfuric acid solution that is the second flow path discharge water produced and discharged from the ammonia gas conversion unit (100) described later, i.e., the stack, or the discharged sulfuric acid solution may be diluted with water and used.

[0048] The third solution above may be a solution containing sodium sulfate, and may be a sodium sulfate solution in which sodium sulfate is dissolved in a solvent, such as water, distilled water, etc.

[0049] Additionally, the ammonia gas conversion unit (100) includes an oxidation electrode unit (210) and a reduction electrode unit (250) positioned at a predetermined distance from the oxidation electrode unit (210).

[0050] Additionally, the ammonia gas conversion unit (100) includes a cation exchange membrane (310), an anode membrane (330), and an anion exchange membrane (350) arranged to sequentially partition a first flow path (410) fluidly connected to a first supply unit (110), a second flow path (420) fluidly connected to a second supply unit (120), and a third flow path (430) fluidly connected to a third supply unit (130) between an oxidation electrode unit (210) and a reduction electrode unit (250).

[0051] Here, the cation exchange membrane (310), the anode membrane (330), and the anion exchange membrane (350) each include one or more, and the cation exchange membrane (310), the anode membrane (330), and the anion exchange membrane (350) may be arranged sequentially between the oxidation electrode and the reduction electrode.

[0052] That is, a first flow path (410) can be formed between the cation exchange membrane (310) and the anode membrane (330), a second flow path (420) can be formed between the anode membrane (330) and the anion exchange membrane (350), and a third flow path (430) can be formed between the anion exchange membrane (350) and the cation exchange membrane (310).

[0053] The above ammonia gas conversion unit (100) may be an electrodialysis stack including an anode membrane (330).

[0054] The above ammonia gas conversion unit (100) includes a power supply unit (PS) provided to apply voltage to each of the oxidation electrode unit (210) and the reduction electrode unit (250).

[0055] In the drawing of FIG. 2, three triplets, which are unit cell structures composed of a cation exchange membrane, an anode membrane, and an anion exchange membrane, are shown sequentially from the oxidation electrode (210) toward the reduction electrode (250), but it should be understood that additional triplets may be included.

[0056] In particular, the ion exchange membrane positioned closest to the oxidation electrode (210) may be a cation exchange membrane (310'), and the ion exchange membrane positioned closest to the reduction electrode (250) may be an anion exchange membrane (350').

[0057] Here, an electrode solution channel (440) may be formed between the oxidation electrode (210) and the cation exchange membrane (310') closest to the oxidation electrode (210), and an electrode solution channel (440) may be formed between the reduction electrode (250) and the anion exchange membrane (350') closest to the reduction electrode (250).

[0058] An electrode solution supply unit (not shown) for supplying an electrode solution may be fluidly connected to the electrode solution flow path (440), and the electrode solution flow paths (440) may be fluidly connected to each other so that the electrode solution circulates.

[0059] The electrode solution channel (440) is fluidly connected to the third supply unit (130) so that the third solution can be supplied to the electrode solution channel (440).

[0060] As described above, when supplying the third solution, a sodium sulfate solution, to the electrode solution flow path (440), sodium ions (Na + ) and sulfate ions (SO4 2- ) passes through the cation exchange membrane (310') and the anion exchange membrane (350') respectively and moves to the adjacent first flow path (410) and second flow path (420), and can be discharged as the first flow path discharge water and the second flow path discharge water, respectively.

[0061] Furthermore, when supplying the third solution, a sodium sulfate solution, to the third Euro (430), sodium ions (Na + ) and sulfate ions (SO4 2- ) passes through the anion exchange membrane (350) and cation exchange membrane (310) that partition the third flow path, respectively, and moves to the adjacent first flow path (410) and second flow path (420), and can be discharged as the first flow path discharge water and second flow path discharge water, respectively.

[0062] The first supply unit (110) includes a first line (L1) that is fluidly movably connected to one or more first flow paths (410), the second supply unit (120) includes a second line (L2) that is fluidly movably connected to one or more second flow paths (420), and the third supply unit (130) includes a third line (L3) that is fluidly movably connected to one or more third flow paths (430).

[0063] Here, the third supply unit (130) and the electrode solution flow path (440) can be fluidly connected through the third line (L3).

[0064] Each of the above first flow paths (410) discharges a first flow path discharge water, which is a solution containing ammonia gas generated during the process of a first solution supplied from the first supply unit (110) passing through the first flow path (410).

[0065] The above ammonia gas conversion unit (100) includes a fourth line (L4) that fluidly connects the first flow path and the membrane contact part to supply the first flow path discharge water discharged from each first flow path (410) to the membrane contact part (500).

[0066] Each of the above second flow paths (420) discharges a second flow path discharge water, which is a sulfuric acid solution generated during the process of the second solution supplied from the second supply unit (120) passing through the second flow path (420).

[0067] The above ammonia gas conversion unit (100) includes a fifth line (L5) that fluidly connects the second flow path and the second supply unit (120) to recirculate the second flow path discharge water discharged from each second flow path (420) to the second supply unit (120).

[0068] Each of the above third channels (430) discharges a third channel discharge water, which is a sodium sulfate solution in which at least a portion is consumed as the third solution supplied from the third supply unit (130) passes through the third channel (430).

[0069] The above ammonia gas conversion unit (100) includes a sixth line (L6) that fluidly connects the third flow path and the third supply unit (130) to resupply the third flow path discharge water discharged from each third flow path (430) to the third supply unit (130).

[0070] The first to third lines above can be connected to the inlet side of each flow path, and the fourth to sixth lines can be connected to the discharge side of each flow path.

[0071] The above ammonia gas conversion unit (100) supplies at least a portion of the sulfuric acid solution received in the second supply unit (120) to the membrane contact unit (500) and includes a solution supply unit (170) provided to receive the sulfuric acid solution transferred from the second supply unit (120).

[0072] Additionally, the solution supply unit (170) can receive the ammonium sulfate solution produced in the membrane contact unit (500).

[0073] That is, the solution supply unit (170) can receive the sulfuric acid solution transferred from the second supply unit (120) and the ammonium sulfate solution produced and transferred from the membrane contact unit (500), and accordingly, the solution supply unit (170) can receive a mixed solution in which the sulfuric acid solution and the ammonium sulfate solution are mixed.

[0074] The above solution supply unit (170) includes a seventh line (L7) that is fluidly movable and connected to the second supply unit (120).

[0075] The above solution supply unit (170) includes an 8th line (L8) that is fluidly movable to supply a sulfuric acid solution to a membrane contact unit (500).

[0076] The above solution supply unit (170) includes a ninth line (L9) that is fluidly movably connected to the membrane contact unit (500) to supply the ammonium sulfate solution produced in the membrane contact unit (500) to the solution supply unit (170).

[0077] The above membrane contact portion (500) can produce an ammonium sulfate solution by supplying the first flow path discharge water supplied from the first flow path (410) and the second flow path discharge water supplied from the solution supply portion (170), respectively, and through contact between the ammonia gas contained in the first flow path discharge water and the sulfuric acid solution contained in the second flow path discharge water.

[0078] At this time, the membrane contact portion (500) includes a treated water receiving portion (620) in which wastewater, for example, treated wastewater, is discharged after ammonia nitrogen has been treated by contact between the first flow path discharge water supplied from the first flow path (410) and the second flow path discharge water supplied from the solution supply portion (170). The treated water receiving portion (620) can be fluidly connected to the membrane contact portion (500) through the 10th line (L10), and the treated wastewater can be discharged into a water system through a discharge line (L10') provided in the treated water receiving portion (620).

[0079] The above-mentioned treated water receiving section (620) may include a sewage treatment plant capable of linked treatment, but is not limited thereto.

[0080] Here, the membrane contact portion (500) is a membrane contactor, and when a sulfuric acid solution is flowed on one side and a solution containing ammonia gas is flowed on the other side with a membrane having fine holes between them, the ammonia gas passes through the membrane and moves toward the sulfuric acid solution side due to the difference in gas partial pressure, and the sulfuric acid solution and the ammonia gas react to produce an ammonium sulfate solution.

[0081] Additionally, the above-mentioned membrane contact portion (500) includes a solution storage portion (600) for receiving the produced ammonium sulfate solution.

[0082] The above solution storage unit (600) can receive and receive the ammonium sulfate solution supplied from the solution supply unit (170) to the solution supply unit (170) from the membrane contact unit (500), and the received ammonium sulfate solution can be used as fertilizer, i.e., liquid fertilizer, and can be used as liquid fertilizer by additionally mixing other substances used for liquid fertilizer.

[0083] The above solution storage unit (600) may include a 11th line (L11) that is fluidly movably connected to the solution supply unit (170).

[0084] Meanwhile, the ammonia nitrogen recovery device (10) may additionally include a control unit (C; C1 to C11, which may be referred to as the first to eleventh control units) for controlling the flow of one or more fluids.

[0085] The above control unit may include a pump (P) and a valve (B), and can control the flow rate and flow of the fluid using the pump (P) or the valve (B).

[0086] That is, in each of the aforementioned lines (L1 to L11), a pump (P; P1 to P11, which may be referred to as the first to eleventh pumps) may be disposed for controlling the flow rate of the fluid and controlling the flow of the fluid, but is not limited thereto, and a pump (P) may be disposed optionally as needed.

[0087] In addition, each of the aforementioned lines (L1 to L11) may be equipped with a respective valve (B; B1 to B11, which may be referred to as the first to eleventh valves) for controlling the flow of fluid and regulating the fluid flow, but is not limited thereto, and a valve (B) may be optionally provided as needed.

[0088] In the following description, a control unit (C) for controlling fluid flow may refer to a pump or valve, or a pump and a valve.

[0089] In addition, the ammonia nitrogen recovery device (10) may further include one or more sensing units (S; S1 to S11, which may be referred to as the first to fourth sensing units) for detecting the state of the fluid flowing through each line (L1 to L11).

[0090] That is, each of the aforementioned lines (L1~L11) may have a respective sensor unit for monitoring the state of the fluid, but is not limited thereto, and a sensor unit (S) may be selectively placed as needed.

[0091] Here, the sensing unit (S) may include one or more sensors for measuring at least one selected of the fluid flow rate, pressure, and conductivity, but is not limited thereto, and sensors may be selectively placed on the lines as needed, and sensors required for each line may be selected and placed.

[0093] Meanwhile, an ammonia nitrogen recovery device (10) according to one embodiment of the present invention may further include a control unit provided to control the flow of the first to third solutions, the first flow path discharge water, and the second flow path discharge water.

[0094] Specifically, an ammonia nitrogen recovery device (10) according to one embodiment of the present invention includes a first operating mode (initial operating mode) for producing a sulfuric acid solution in an ammonia gas conversion unit (100), a second operating mode (normal operating mode) for treating wastewater (anaerobic digestion treated water, etc.) containing ammonia nitrogen and producing fertilizer, and a third operating mode (cleaning operating mode) for adjusting the pH of the ammonia gas conversion unit (100) (for cleaning the ammonia gas conversion unit).

[0095] The above nitrogen recovery device (10) may additionally include a control unit (not shown) for selectively performing first to third operating modes as needed.

[0096] The above first to third supply units (110, 120, 130) may additionally include first to third control units (C1 to C3) for controlling fluid flow, each disposed on the first to third lines (L1 to L3).

[0097] The above control unit is electrically connected to each control unit (C1 to C3) arranged on the first to third lines and can control the flow of the first to third solutions contained in each supply unit.

[0098] For example, the control unit may control the flow and flow rate of the solution by selectively opening and closing or adjusting the opening degree of one or more of the first to third valves, or control the flow and flow rate of the solution by adjusting the rotational speed of one or more of the first to third pumps corresponding to a selected flow rate value.

[0099] As stated above, in this document, a control unit may refer to a valve or a pump. For example, the first to eleventh control units may each be the first to eleventh valves or the first to eleventh pumps.

[0100] Additionally, the nitrogen recovery device (10) may further include a fourth control unit (C4) positioned on the fourth line (L4), and the control unit may be electrically connected to the fourth control unit (C4) to control the flow of the first flow path discharge water.

[0101] Additionally, the nitrogen recovery device (10) may further include a seventh control unit (C7) positioned on the seventh line (L7), and the control unit may be electrically connected to the seventh control unit (C7) to control the flow of concentrated second flow path discharge water supplied from the second supply unit (120) to the solution supply unit (170).

[0102] Additionally, the nitrogen recovery device (10) may further include an eighth control unit (C8) positioned on an eighth line (L8), and the control unit may be electrically connected to the eighth control unit (C8) to selectively control the eighth control unit to control the flow of the first flow path discharge water and / or the mixed solution of the first flow path discharge water and ammonium sulfate solution mixed, which is supplied from the solution supply unit (170) to the membrane contact unit (500).

[0103] Additionally, the nitrogen recovery device (10) may further include a first control unit (C11) disposed on a first line (L11), and the control unit may be electrically connected to the first control unit (C11) to selectively control the first control unit to control the flow of the ammonium sulfate solution contained in the solution supply unit (170) and / or the mixed solution in which the ammonium sulfate solution and the second flow path discharge water are mixed.

[0104] Here, in addition to the aforementioned valves, the valves may be additionally placed on each line as needed and electrically connected to a control unit to control the flow of fluid flowing through each line, thereby enabling the automatic operation of the device.

[0106] FIGS. 3 and 4 are drawings illustrating a first operating mode of a nitrogen recovery device (10) according to one embodiment of the present invention.

[0107] Referring to FIGS. 3 and FIGS. 4, the nitrogen recovery device (10) can be operated in a first operating mode by a control unit.

[0108] The first operating mode above includes a concentration mode for concentrating the second flow path discharge water (sulfuric acid solution) and a transfer mode for transferring the concentrated second flow path discharge water (sulfuric acid solution) to the solution supply unit (700).

[0109] First, the nitrogen recovery device (10) may additionally include a circulation line (L1') provided to circulate fluid discharged from each first flow path (410) to a first supply unit (110), and the circulation line (L1') may be branched from at least a portion of the fourth line (L4) and connected to allow fluid movement to the first supply unit (110).

[0111] Referring to FIG. 3, the control unit can control the first solution or water contained in the first supply unit to be supplied to the respective first flow paths and recirculated to the first supply unit through the circulation line (L1') when operating in the concentration mode of the first operating mode, and control the second and third solutions to be supplied to the second and third flow paths, respectively, to produce the second flow path discharge water (sulfuric acid solution).

[0112] Specifically, the control unit operates the first to third control units (C1 to C3) to operate the first to third solutions so that they are supplied to their respective flow paths. At this time, the first solution may be operated to move along the circulation line (L1') branched from the first line (L1) and the fourth line and circulate to the first supply unit (110).

[0113] For example, the control unit operates the first valve (B1) to an open state and the fourth valve (B4) to a closed state so that the first solution or water circulates to the first supply unit through the circulation line (L1'), and controls the second and third valves (B2, B3) to an open state respectively so that the second and third solutions are supplied to the second and third flow paths (420, 430) respectively.

[0114] At the same time, the control unit controls the power supply unit (PS) to apply voltage to the oxidation electrode unit (210) and the reduction electrode unit (250).

[0115] When the first to third solutions are supplied respectively as described above, the sulfate ions (SO4) among the sodium sulfate contained in the third solution supplied to the third flow path 2- ) passes through the anion exchange membrane (350) partitioning the third Euro (430) and moves to the second Euro (420).

[0116] At this time, the anode membrane (330) partitioning the second flow path (420) decomposes the water contained in the second solution by the voltage applied to each electrode and supplies hydrogen ions onto the second flow path (420).

[0117] Here, the anode membrane (330) is composed of a cation exchange layer and an anion exchange layer, and when current is applied to the oxidation electrode and the reduction electrode, water decomposition, i.e., H2O, occurs at the junction of the cation exchange layer and the anion exchange layer. + Wow OH - It is a membrane that is decomposed and through which cations and anions cannot move through the anode membrane (330).

[0118] In particular, the anion exchange layer of the anode membrane (330) may be positioned to face the oxidation electrode portion (210), and the cation exchange layer may be positioned to face the reduction electrode portion (250).

[0119] As described above, in the second flow path (420), hydrogen ions supplied by the water decomposition of the anode membrane and sulfate ions moved from the third flow path combine to form a sulfuric acid solution (H2SO4), which flows along the fifth line (L5) as the second flow path discharge water and is received in the second supply unit (120).

[0120] Here, in the third flow path (430), as the sulfate ions and sodium ions among the supplied third solution move through the respective membranes to adjacent flow paths, the discharge water of the third solution from which the sulfate ions and sodium ions have been consumed can be recirculated to the third supply unit (130) along the sixth line (L6). Sodium sulfate may be additionally supplied to the third supply unit (130), and the third solution containing the additionally supplied sodium sulfate may be arranged to circulate from the third supply unit (130) along the third line (L3), the third flow path (430), and the sixth line (L3) in sequence to the third supply unit (130).

[0121] The above control unit can control the concentration mode to be operated for a preset time or a preset cycle (number of times) so that the sulfuric acid solution is concentrated in the second supply unit (120).

[0122] In addition, the control unit controls the operation to terminate the sulfuric acid solution concentration mode and operate in the transfer mode when the sulfuric acid solution contained in the second supply unit is concentrated to a predetermined concentration.

[0123] Referring to FIG. 4, the control unit controls the first to third control units (C1 to C3) to stop the supply of the first to third solutions to the first to third flow paths when operating in the first operating mode, and controls the seventh control unit (C7) so that the second flow path discharge water (sulfuric acid solution) moves along the seventh line (L7) and is transferred to the solution supply unit (170).

[0124] For example, in the transfer mode of the first operating mode, when the second flow path discharge water is received by the second supply unit, the control unit controls the seventh valve from a closed state to an open state to supply the second flow path discharge water to the solution supply unit (170). At this time, the first to third valves can each be controlled from an open state to a closed state.

[0125] Through the above process, in the first operating mode, the second flow path discharge water is stored in a separately provided solution supply unit (170), and the stored second flow path discharge water (sulfuric acid solution) is directly supplied to the membrane contact unit (500), thereby having the effect of fundamentally preventing the leakage of ammonium ions that occurred in the existing technology.

[0126] As described above, when the second Euro discharge water is received in the solution supply unit (170), the control unit terminates the first operating mode and controls the operation to run in the second operating mode.

[0127] Here, the control unit can be controlled to operate for a preset time, and can be controlled to stop the operation of the first operation mode and operate the second operation mode when the internal water level of the supply unit exceeds a reference value through a sensor capable of measuring the level of the fluid contained therein based on the storage capacity of at least one of the second supply unit (120) and the solution supply unit (170).

[0129] FIG. 5 is a diagram illustrating a second operating mode of a nitrogen recovery device (10) according to one embodiment of the present invention.

[0130] Referring to FIG. 5, the nitrogen recovery device (10) can be operated in a second operating mode by a control unit.

[0131] The above second operating mode includes a continuous operating mode that produces an ammonium sulfate solution that can be used as fertilizer while treating wastewater, a discharge operating mode that discharges the treated water (treated wastewater) into a water system, and a fertilizer supply mode for utilizing the ammonium sulfate solution as fertilizer, and the control unit can control the operation by selecting at least one of the continuous operating mode, the discharge operating mode, and the fertilizer supply mode in the second operating mode.

[0132] For example, the control unit can select and control a continuous operation mode and a discharge operation mode, control to operate by selecting only the continuous operation mode, or control by selecting all modes.

[0133] The above control unit can control the operation of the continuous operation mode during the second operation mode by supplying the first to third solutions to the respective first to third flow paths, thereby allowing sulfate ions and sodium ions in the third solution to selectively pass through an adjacent membrane and be supplied from the third flow path to an adjacent flow path, converting the ammoniacal nitrogen contained in the first solution into ammonia gas in the first flow path, and producing the aforementioned sulfuric acid solution in the second flow path.

[0134] Specifically, the control unit controls all first to third control units to an operating state during the continuous operation mode of the second operation mode, thereby operating to supply the first to third solutions to the first to third flow paths, respectively. At this time, the fourth control unit is also controlled to an operating state so that the first solution does not flow into the circulation line (L1') but flows along the fourth line (L4).

[0135] For example, the control unit controls the first to third valves (B1 to 3) to be all open in the continuous operation mode of the second operation mode, thereby operating to supply the first to third solutions to the first to third flow paths, respectively.

[0136] In addition, the control unit can control the first to third control units, the fourth control unit (C4), and the eighth control unit (C8) to each be in an operating state in the second operating mode so that fluid flows along each line, and control the seventh control unit (C7) so that fluid does not flow in the seventh line, thereby operating so that fluid corresponding to each line flows along the first to third lines, the fourth line, and the eighth line.

[0137] For example, the control unit can operate by controlling the first to third valves, the fourth valve, and the eighth valve to each open state in the second operating mode, and controlling the seventh valve to a closed state so that fluid flows.

[0138] At the same time, the control unit controls the power supply unit (PS) to apply voltage to the oxidation electrode unit (210) and the reduction electrode unit (250). The voltage application may be maintained following the first operating mode described above.

[0139] Specifically, when the first to third solutions are supplied as described above, the sulfate ions (SO4) among the sodium sulfate contained in the third solution supplied to the third flow path 2-) passes through the anion exchange membrane (350) partitioning the third flow path (430) and moves to the second flow path (420), and sodium ions (Na + ) passes through the cation exchange membrane (310) partitioning the third Euro (430) and moves to the first Euro (410).

[0140] At this time, in the anode membrane (330) partitioning the first flow path (410), an anion exchange layer is arranged to face the oxidation electrode portion (210), so that hydroxide ions (OH) generated by the water decomposition of the anode membrane - ) supplies to the first Euro (410).

[0141] Accordingly, the pH in each first flow path (410) is raised by the hydroxide ions generated by the water splitting of the bipolar membrane, and the ammonium ions can be more easily converted into ammonia gas by shifting the equilibrium.

[0142] As described above, the first flow path discharge water, which is a solution containing ammonia gas generated in the first flow path, is supplied to the membrane contact part (500) along the fourth line (L4).

[0143] At the same time, in the anode membrane (330) partitioning the second Euro (420), a cation exchange layer is arranged to face the reduction electrode portion (250), so that hydrogen ions (H) generated by water decomposition of the anode membrane are present. + ) supplies the second Euro (420).

[0144] Accordingly, the second flow path (420) discharge water, which is a sulfuric acid solution produced by the combination of sulfate ions and hydrogen ions supplied from an adjacent flow path, is supplied to the second supply unit (120) along the fifth line (L5), and the sulfuric acid solution is concentrated as it is stored in the second supply unit.

[0145] At this time, the second flow path discharge water (sulfuric acid solution) received in the solution supply unit (170) through the transfer mode during the first operating mode is supplied to the membrane contact unit (500) along the 8th line (L8). As described above, the first flow path discharge water and the second flow path discharge water generate an ammonium sulfate solution ((NH4)2SO4) at the membrane contact unit (500) and are recirculated to the solution supply unit (170) along the 9th line (L9). In this way, when the ammonium sulfate solution discharged to the solution supply unit (170) is recirculated to the membrane contact unit (500) to circulate the ammonium sulfate solution, a high concentration of ammonium sulfate solution can be produced through the membrane contact unit (500).

[0146] At the same time, the treated water from which ammonia nitrogen has been removed can be supplied to the treated water receiving section (620) along the 10th line (L10).

[0147] Here, when the control unit selects a discharge operation mode as needed, it can measure the concentration of total ammoniacal nitrogen through the detection unit (S6) placed in the 10th line (L10), and when it is below the reference value, discharge it into the water system through the discharge line (L10').

[0148] That is, in the discharge operation mode, when the value measured through the detection unit is below the reference value, the control unit can control the discharge control unit (C10') placed in the discharge line (L10') to, for example, control the discharge valve (B10') to open the discharged water.

[0149] Additionally, in the second operating mode, when the fertilizer production mode is selected, that is, when the ammonium sulfate solution or concentrated ammonium sulfate solution contained in the solution supply unit (170) is supplied to the solution storage unit (600) to be used as fertilizer, the control unit can control the 11th control unit (C11) to, for example, control the 11th valve (B11) from a closed state to an open state to supply the ammonium sulfate solution from the solution supply unit (170) to the solution storage unit (600) through the 11th line.

[0150] Here, in the fertilizer production mode, the control unit can control the first control unit when the internal water level of the supply unit exceeds a reference value through a sensor capable of measuring the level of the fluid containing the ammonium sulfate solution in the solution supply unit (170) based on the storage capacity of the solution supply unit (170), for example, by controlling the first valve (B11) from a closed state to an open state to allow the solution to flow into the solution storage unit (600).

[0151] In addition, when the internal capacity is exceeded or a preset operating time has elapsed, the aforementioned valve may be automatically controlled to control the flow of the solution into the solution storage unit.

[0153] FIG. 6 is a diagram illustrating a third operating mode of a nitrogen recovery device (10) according to one embodiment of the present invention.

[0154] Referring to FIG. 6, the nitrogen recovery device (10) can be operated in a third operating mode by a control unit.

[0155] The above third operating mode can be controlled by a control unit to clean each flow path within the ammonia gas conversion unit (100, electrodialysis stack) and to prevent the precipitation of calcium ions (CaCO3) due to an increase in pH of the flow path inside the stack.

[0156] First, the nitrogen recovery device (10) may additionally include a first branch line (L21) branched from the second line (L2) and fluidly connected to the first line (L1), and a second branch line (L23) branched from the second line (L2) and fluidly connected to the third line (L3).

[0157] The above-mentioned first branch line (L21) may be configured to supply the second flow path discharge water (sulfuric acid solution) contained in the second supply unit (120) from the second line (L2) to the first line (L1) for pH control of the flow path inside the stack.

[0158] Additionally, the first branch line (L21) may further include a first branch line control unit (C21) configured to allow the second Euro discharge water (sulfuric acid solution) to flow into the first line (L1).

[0159] Additionally, the second branch line (L22) may be configured to supply the second flow path discharge water (sulfuric acid solution) contained in the second supply unit (120) from the second line (L2) to the third line (L3) for pH control of the flow path inside the stack.

[0160] Additionally, the second branch line (L22) may further include a second branch line control unit (C22) configured to allow the second Euro discharge water (sulfuric acid solution) to flow into the third line (L3).

[0161] Additionally, the nitrogen recovery device (10) may further include a third branch line (L23) that branches off from the fourth line (L4) and is fluidly connected to the fifth line (L5).

[0162] The above third branch line (L23) may be configured so that the pH-regulating discharge water flows from the fourth line (L3) to the fifth line (L5) in order to circulate the discharge solution (pH-regulating discharge water) discharged after the pH of the second flow path (sulfuric acid solution) supplied for pH adjustment passes through each first flow path (410) and the pH of the flow path is adjusted (after lowering the pH) to the second supply unit (120).

[0163] Additionally, the third branch line (L23) may further include a third branch line control unit (C23) configured to allow pH-controlled discharge water to flow into the fifth line (L5).

[0164] Additionally, the nitrogen recovery device (10) may further include a fourth branch line (L24) that branches off from the sixth line (L6) and is fluidly connected to the fifth line (L5).

[0165] The above-mentioned fourth branch line (L24) may be configured so that the pH-regulating discharge water flows from the sixth line (L6) to the fifth line (L5) in order to circulate the discharge solution (pH-regulating discharge water) discharged after the second flow path discharge water (sulfuric acid solution) supplied for pH adjustment passes through each third flow path (430) and the pH of the flow path is adjusted (after lowering the pH) to the second supply unit (120).

[0166] Additionally, the fourth branch line (L24) may further include a fourth branch line control unit (C24) configured to allow pH-controlled discharge water to flow into the fifth line (L5).

[0167] The above control unit may terminate the second operating mode to operate the third operating mode. At this time, the control unit may terminate the second operating mode by controlling the first to eleventh control units (C1 to C11) so that fluid does not flow in all flow paths. Here, the control unit controls the power supply unit (PS) so that voltage is not applied to the oxidation electrode unit (210) and the reduction electrode unit (250).

[0168] Next, the control unit controls the second control unit (C2) so that the second flow discharge water (concentrated sulfuric acid solution) flows through the first to third flow paths, respectively, and controls the first and second branch line control units (C21, C22) provided in the first and second branch lines (L21, L23), respectively, so that, for example, the second valve and the first and second branch line valves are switched from a closed state to an open state, thereby controlling the operation of the third operating mode.

[0169] In addition, the control unit controls the third and fourth branch line control units (C23, C24) to control the pH-controlled discharge water discharged through the first to third paths, respectively, to circulate along the fifth line (L5) to the second supply unit (120), for example, to control the third and fourth branch line valves to switch from a closed state to an open state so that the third operating mode is operated.

[0170] Accordingly, the second flow path discharge water (concentrated sulfuric acid solution) flows along each of the first to third lines and is supplied to the first to third flow paths (410 to 430) to adjust the pH within each flow path, and the discharged pH-adjusted discharge water is transferred back to the second supply unit (120).

[0171] Here, the second supply unit (120) used in the third operating mode may be referred to as a pH control supply unit. That is, the pH control supply unit may be the second supply unit (120).

[0173] Accordingly, the pH of the internal flow path of the stack is lowered, which prevents the precipitation of calcium ions.

[0174] Here, the second flow path discharge water (sulfuric acid solution) supplied to each flow path from the second supply unit (pH control supply unit) may be the second flow path discharge water diluted by adding water.

[0175] As described above, pH-controlled wastewater supplied from the pH-controlled supply unit (120) and discharged through each of the first to third flow paths can be transferred back to the pH-controlled supply unit (120) and then discharged to the outside along the wastewater discharge line (L2') which is fluidly movable to the pH-controlled supply unit (120, second supply unit).

[0176] After the third operating mode is terminated as described above, water is supplied to the second supply unit (120) again, and the first operating mode described above can be performed.

[0177] Meanwhile, the first sensing unit (S1) may include a sensor positioned on the first line (L1) on the first supply unit side and configured to measure the flow rate and pressure of the first solution flowing through the first line (L1), respectively.

[0178] Additionally, the second sensing unit (S2) may include a sensor positioned on the second line (L2) on the second supply unit side and configured to measure the flow rate and pressure of the second solution flowing through the second line (L2), respectively.

[0179] Additionally, the third sensing unit (S3) may include a sensor positioned on the third line (L3) on the third supply unit side and configured to measure the flow rate, pressure, and conductivity of the third solution flowing through the third line (L3), respectively.

[0180] Here, the conductivity measuring sensor may be provided to measure the concentration of the solution flowing through the channel.

[0181] Additionally, the fourth detection unit (S4) may include a sensor arranged on the fourth line (L4) through which the first flow path discharge water (a solution containing ammonia gas) discharged from the ammonia gas conversion unit (100) flows, and configured to measure the pH of the first flow path discharge water flowing through the fourth line (L4).

[0182] Additionally, the fifth sensing unit (S5) may include a sensor arranged to measure the flow rate, pressure, and conductivity of the second flow path discharge water (sulfuric acid solution) supplied to the membrane contact unit (500) by flowing through the eighth line (L8) and / or the ammonium sulfate solution discharged from the membrane contact unit (500) and the mixed solution thereof, respectively.

[0183] Additionally, the fifth detection unit (S6) is positioned on the 10th line (L10) and may include a sensor for measuring the concentration of total ammoniacal nitrogen (TAN) in the treated wastewater that flows through the 10th line (L10) and is supplied to the treated water receiving unit (620). Referring again to FIG. 2, the first to third solutions are supplied to the first to third flow paths of the ammonia gas conversion unit, respectively, and the electrode solution is supplied to the electrode side. The movement of ions under the condition where current is applied to the oxidation electrode (211) and the reduction electrode (351) is described as follows.

[0184] In the first flow path, sodium ions (Na+) contained in the electrode solution (e.g., the third solution) supplied to the oxidation electrode (211) or sodium ions (Na+) contained in the third solution supplied to the third flow path each pass through the cation exchange membrane (310) and move to the first flow path (410), and hydroxide ions (OH-) formed by water decomposition in the anode membrane (330) are supplied to the first flow path (410), and as the pH in the first flow path rises due to the hydroxide ions, the ammoniacal nitrogen contained in the first solution is converted into a gaseous form, and the first flow path discharge water containing ammonia gas is discharged.

[0185] Additionally, in the second flow path, hydrogen ions (H+) formed by water decomposition in the anode membrane (330) are supplied to the second flow path (420), and at the same time, sulfate ions (SO4) contained in the third solution supplied to the third flow path are supplied. 2- ) passes through the anion exchange membrane (350), and in the second flow path (420), a sulfuric acid solution (H2SO4) is formed and discharged from the second flow path.

[0186] Additionally, in the third flow path, sodium ions (Na+) contained in the third solution supplied to the third flow path pass through the cation exchange membrane (310) and move to the first flow path (410), and sulfate ions (SO4 2- ) passes through the anion exchange membrane (350) and moves to the second flow path (420), so that the third solution, which has a lower concentration than the initial concentration of the supplied third solution, is discharged as the third flow path discharge water and can be re-supplied to the third supply unit (130).

[0187] As described above, by using wastewater as the first solution supplied to the first flow path, water or a diluted sulfuric acid solution as the second solution supplied to the second flow path, and a sodium sulfate solution as the third solution supplied to the third flow path, and by placing a cation exchange membrane (310') as the ion exchange membrane closest to the oxidation electrode side and an anion exchange membrane (350') as the ion exchange membrane closest to the reduction electrode side, the foreign substances that may be formed on the electrode side and the foreign substances formed on the ion exchange membrane can be minimized, thereby providing an electrodialysis stack, an ammonia nitrogen recovery device using the same, and an ammonia nitrogen recovery system using the same.

[0188] FIG. 7 is a drawing showing a nitrogen recovery system (11) using a nitrogen recovery device (10) according to one embodiment of the present invention described above.

[0189] Referring to FIG. 7, the nitrogen recovery system (11) may include one or more ammonia gas conversion units (100; 100a, 100b) and one or more membrane contact units (500).

[0190] Specifically, the ammonia gas conversion unit may include a first ammonia gas conversion unit (100a) and a second ammonia gas conversion unit (100b), but is not limited thereto.

[0191] Additionally, the above-mentioned membrane contact portion (500; 500a, 500b, 500c) may include a first membrane contact portion (500a), a second membrane contact portion (500b), and a third membrane contact portion (500c), but is not limited thereto.

[0192] The above nitrogen recovery system (11) may, as needed, have the first ammonia gas conversion unit (100a) and the second ammonia gas conversion unit (100b) simultaneously operated in a selected operating mode among the same first to third operating modes.

[0193] For example, the first and second ammonia gas conversion units (100a, 100b) can be operated in a first operating mode or a second operating mode to produce second flow path discharge water or / and first flow path discharge water.

[0194] Additionally, the nitrogen recovery system (11) may, as needed, have the first ammonia gas conversion unit (100a) and the second ammonia gas conversion unit (100b) simultaneously operated in a selected operating mode among the first to third operating modes that are different from each other.

[0195] For example, when the first ammonia gas conversion unit (100a) is operated in a first operation mode or a second operation mode to produce the second flow path discharge water or / and the first flow path discharge water, the second ammonia gas conversion unit (100b) is operated in a third operation mode, so that the first ammonia gas conversion unit and the second ammonia gas conversion unit are controlled to operate alternately, thereby enabling continuous operation.

[0196] In addition, the first membrane contact part (500a), the second membrane contact part (500b), and the third membrane contact part (500c) can be operated alternately, and if replacement of any one of the first to third membrane contact parts is required, the remaining two membrane contact parts can be operated so as to enable continuous operation.

[0197] Meanwhile, FIG. 8 is a graph showing the removal rate of ammonia nitrogen according to the change in concentration of a first solution containing ammonia nitrogen in an ammonia nitrogen recovery device according to one embodiment of the present invention.

[0198] The experimental result graph confirmed that as the concentration of the first solution (wastewater) containing ammoniacal nitrogen increased, the removal rate of total ammoniacal nitrogen (TAN) contained in the wastewater increased.

[0199] In addition, it was confirmed that the removal rate of total ammonia nitrogen (TAN) contained in wastewater increases as the flow rate of the supplied solution increases. Explanation of the symbols

[0201] 100: Ammonia gas conversion unit 110: 1st supply unit 120: Second supply unit (pH control supply unit) 130: Third supply unit 170: Solution supply unit 210: Oxidation electrode section 250: Reduction electrode section 310: Cation exchange membrane 330: Bipolar Tabernacle 350: Anion exchange membrane 500: Separator contact part 600: Solution reservoir 620: Treated water receiving section (linked sewage treatment plant)

Claims

Claim 1 A first supply unit for supplying a first solution containing ammoniacal nitrogen; a second supply unit for supplying a second solution containing water; a third supply unit for supplying a third solution containing sodium sulfate; an oxidation electrode unit and a reduction electrode unit disposed at a predetermined distance from the oxidation electrode unit; and a plurality of unit cells comprising one or more cation exchange membranes, a bipolar membranes, and anion exchange membranes arranged sequentially to sequentially partition a first flow path fluidly connected to the first supply unit, a second flow path fluidly connected to the second supply unit, and a third flow path fluidly connected to the third supply unit, wherein the plurality of unit cells are arranged sequentially; and a separation membrane contact unit for producing an ammonium sulfate solution through contact between the ammonia gas contained in the first flow path discharge water and the sulfuric acid contained in the second flow path discharge water, wherein the first flow path discharge water discharged from the first flow path and the second flow path discharge water discharged from the second flow path are respectively supplied. An ammonia gas conversion unit comprising, wherein the ammonia gas conversion unit further comprises a solution supply unit separately provided to supply sulfuric acid contained in the second flow path discharge water to the membrane contact unit, wherein the second flow path discharge water is supplied to the membrane contact unit through the solution supply unit, and further comprises a control unit provided to control the flow of the first to third solutions, the first flow path discharge water, and the second flow path discharge water, wherein the control unit comprises a first operating mode for producing the second flow path discharge water in the ammonia gas conversion unit; a second operating mode for treating ammonia nitrogen by contacting the first flow path discharge water and the second flow path discharge water in the membrane contact unit and producing an ammonium sulfate solution; and a third operating mode for adjusting the pH of the ammonia gas conversion unit, wherein the control unit controls the operation to select one or more of the first to third operating modes as needed. Claim 2 delete Claim 3 In claim 1, the first operating mode includes a concentration mode for concentrating the second flow path discharge water and a transfer mode for transferring the concentrated second flow path discharge water to a solution supply unit, and the control unit controls the operation of the concentration mode to stop when the transfer mode is operated, an ammonia nitrogen recovery device. Claim 4 An ammonia nitrogen recovery device according to claim 1, wherein the control unit controls the second flow path discharge water produced in the second operation mode and received in the second supply unit to be supplied to each of the first to third flow paths when operating in the third operation mode, and controls the pH-controlled discharge water discharged through each of the first to third flow paths to be circulated to the second supply unit. Claim 5 An ammonia nitrogen recovery device according to claim 1, wherein the first supply unit comprises a first line fluidly movably connected to one or more first flow paths, the second supply unit comprises a second line fluidly movably connected to one or more second flow paths, the third supply unit comprises a third line fluidly movably connected to one or more third flow paths, the first supply unit comprises a fourth line fluidly movably connecting the first flow path and the membrane contact part so that the first flow path discharge water discharged through each first flow path is supplied to the membrane contact part, the second supply unit comprises a fifth line fluidly movably connecting the second flow path and the second supply unit so that the second flow path discharge water discharged through each second flow path is re-supplied to the second supply unit, and the third flow path and the third supply unit fluidly movably connecting the third supply unit so that the third flow path discharge water discharged through each third flow path is re-supplied to the third supply unit. Claim 6 An ammonia nitrogen recovery device according to claim 1, wherein the solution supply unit comprises a seventh line fluidly movably connected to the second supply unit to supply the second flow path discharge water contained in the second supply unit to the solution supply unit, the solution supply unit comprises an eighth line fluidly movably connected to the membrane contact unit to supply the second flow path discharge water to the membrane contact unit, and the solution supply unit comprises a ninth line fluidly movably connected to the solution supply unit and the membrane contact unit to transfer the ammonium sulfate solution produced at the membrane contact unit to the solution supply unit. Claim 7 An ammonia nitrogen recovery system comprising: one or more ammonia gas conversion units according to claim 1; one or more membrane contact units according to claim 1; and a control unit provided to control the flow of first to third solutions, first flow path discharge water and second flow path discharge water, wherein the ammonia gas conversion unit comprises first and second ammonia gas conversion units, the membrane contact unit comprises first to third membrane contact units, and the control unit comprises: a first operating mode for producing second flow path discharge water in the ammonia gas conversion unit; a second operating mode for treating ammonia nitrogen by contacting the first flow path discharge water and the second flow path discharge water in the membrane contact unit and producing an ammonium sulfate solution; and a third operating mode for adjusting the pH of the ammonia gas conversion unit, wherein the control unit controls the operation to select one or more of the first to third operating modes as needed. Claim 8 In claim 7, the control unit controls the first and second ammonia gas conversion units to a selected control mode among the first to third operating modes so that, as needed, the first and second ammonia gas conversion units are simultaneously operated in the same operating mode or in different operating modes, an ammonia nitrogen recovery system. Claim 9 In claim 7, the control unit controls the operation of a selected membrane contact among the first to third membrane contacts as needed, an ammonia nitrogen recovery system. Claim 10 In claim 7, the control unit controls the first ammonia gas switching unit and the second ammonia gas switching unit to operate alternately so that the ammonia nitrogen recovery system is operated continuously, an ammonia nitrogen recovery system.

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