Liquid fertilizer manufacturing device and liquid fertilizer manufacturing method

Abstract

To provide a liquid fertilizer producing apparatus capable of simply producing a liquid fertilizer having a controlled composition ratio of inorganic nitrogen components and a method for producing the liquid fertilizer.SOLUTION: A liquid fertilizer production apparatus for producing liquid fertilizers containing inorganic nitrogen, comprises: control units 24, 26, 28 for setting operating conditions in accordance with a target composition ratio of inorganic nitrogen, a membrane separation unit 20 for biologically treating and membrane separating an organic digestive liquid in accordance with the settings of the control units 24, 26, 28, and an electrodialysis unit 40 for concentrating the separated liquid filtered by the membrane separation unit 20. A liquid fertilizer producing method for producing liquid fertilizer containing inorganic nitrogen, comprises: a control step for setting operating conditions in accordance with the target composition ratio of inorganic nitrogen, a membrane separation step for biologically treating and membrane separating an organic digestive liquid in accordance with the settings of the control step, and an electrodialysis step for concentrating the separated liquid filtered in the membrane separation step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an apparatus and a method for producing liquid fertilizer. [Background technology]

[0002] Liquid fertilizers are useful for the growth of various types of plants, including grains, vegetables, fruits, and flowers. The inorganic nitrogen contained in liquid fertilizers is broadly divided into (1) ammonia nitrogen, (2) nitrate nitrogen, and nitrite nitrogen. Plants have a wide variety of growing conditions, including outdoor cultivation and protected horticulture, and as mentioned above, there are also many different types of plants.

[0003] The composition ratio of inorganic nitrogen required in liquid fertilizer varies depending on the growing conditions and type of plant, and spraying liquid fertilizer that does not have the required composition ratio can cause excessive damage. As a method for producing liquid fertilizer by concentrating digestive fluid of organic matter, Patent Document 1 proposes a method using an ultrafiltration membrane. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-131432 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the method proposed in Patent Document 1, the inorganic nitrogen components in the concentrate obtained by concentrating the digestive fluid of organic matter are mainly ammonia nitrogen, which makes it necessary to change the composition ratio of inorganic nitrogen components depending on the growing conditions and type of plants. Methods for changing the composition ratio of inorganic nitrogen components include, for example, installing equipment such as an activated sludge tank, or spraying liquid fertilizer before planting and leaving it for several days to utilize the nitrification action of microorganisms in the soil. However, all of these methods have the problem of increasing the number of work steps and costs.

[0006] The main object of the present invention is to provide a liquid fertilizer production apparatus and a liquid fertilizer production method that can easily produce liquid fertilizer having an adjusted composition ratio of inorganic nitrogen components. [Means for solving the problem]

[0007] The inventors conducted extensive research into a liquid fertilizer manufacturing apparatus and manufacturing method that can easily adjust the composition ratio of inorganic nitrogen components, and as a result discovered that the above-mentioned problems can be solved by controlling the operating conditions of a membrane separation section that biologically treats the organic digestive liquid and separates it using a membrane, thereby arriving at the present invention.

[0008] That is, the present invention has the following features. [1] A liquid fertilizer manufacturing apparatus for producing liquid fertilizer containing inorganic nitrogen, A control unit that sets operating conditions according to the target composition ratio of inorganic nitrogen; A membrane separation unit that biologically treats the organic digestive liquid and separates it into membranes according to the settings of the control unit; and an electrodialysis section that concentrates the separated liquid filtered by the membrane separation section. [2] The liquid fertilizer manufacturing apparatus described in [1], further comprising a measuring unit for measuring the composition ratio of the separated liquid. [3] A liquid fertilizer manufacturing apparatus as described in [2], wherein the control unit resets the operating conditions based on the measurement values ​​of the measurement unit. [4] The liquid fertilizer production apparatus according to any one of [1] to [3], wherein the membrane separation section is a membrane bioreactor. [5] The liquid fertilizer manufacturing apparatus described in [4], wherein the membrane bioreactor is equipped with a flow rate control device, and the control unit sets the operating conditions of the flow rate control device. [6] A liquid fertilizer manufacturing apparatus as described in [4] or [5], wherein the membrane bioreactor is equipped with a liquid temperature adjustment device, and the control unit sets the operating conditions of the liquid temperature adjustment device. [7] The liquid fertilizer manufacturing apparatus according to any one of [4] to [6], wherein the membrane bioreactor is equipped with a pH adjusting device, and the control unit sets the operating conditions of the pH adjusting device. [8] A liquid fertilizer production method for producing a liquid fertilizer containing inorganic nitrogen, comprising: A method for producing a liquid fertilizer, comprising the following steps (1) to (3): Step (1): A control step of setting operating conditions in accordance with the target composition ratio of inorganic nitrogen; Step (2): A membrane separation step of biologically treating the organic digestive liquid and subjecting it to membrane separation according to the settings of the control step; Step (3): An electrodialysis step for concentrating the separated liquid filtered in the membrane separation step. [9] The method for producing a liquid fertilizer according to [8], further comprising the following step (4): Step (4): A measuring step of measuring the composition ratio of the separated liquid.

[10] A liquid fertilizer manufacturing method as described in [9], in which operating conditions are reset in the control process based on the measured values ​​in the measurement process.

[11] The method for producing a liquid fertilizer described in any one of [8] to

[10] , wherein the membrane separation step is a step using a membrane bioreactor.

[12] The liquid fertilizer production method described in

[11] , wherein the membrane bioreactor is provided with a flow rate adjustment function, and the control process sets operating conditions for the flow rate adjustment function.

[13] The liquid fertilizer production method described in

[11] or

[12] , wherein the membrane bioreactor has a liquid temperature adjustment function, and the control process sets operating conditions for the liquid temperature adjustment function.

[14] The liquid fertilizer production method according to any one of

[11] to

[13] , wherein the membrane bioreactor has a pH adjustment function, and the control step sets operating conditions for the pH adjustment function. Effect of the Invention

[0009] According to the liquid fertilizer production device of the present invention, liquid fertilizer having an adjusted composition ratio of inorganic nitrogen components can be easily produced. According to the liquid fertilizer production method of the present invention, a liquid fertilizer having an adjusted composition ratio of inorganic nitrogen components can be produced by a simple operation. According to the present invention, no additional equipment or work steps are required, and liquid fertilizers with various composition ratios can be quickly provided according to the growing conditions and types of plants. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing an example of an embodiment of a liquid fertilizer manufacturing apparatus of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to these embodiments. The present invention can be implemented in various forms without departing from the spirit of the present invention. The drawings are for the purpose of explaining an example of an embodiment, and are not intended to represent the actual size.

[0012] <Liquid fertilizer production equipment> The liquid fertilizer manufacturing apparatus of the present invention is a liquid fertilizer manufacturing apparatus that produces liquid fertilizer containing inorganic nitrogen, and has a control unit that sets operating conditions in accordance with a target composition ratio of inorganic nitrogen, a membrane separation unit that biologically treats the digestive liquid of organic matter and separates it through membranes in accordance with the settings of the control unit, and an electrodialysis unit that concentrates the separated liquid filtered by the membrane separation unit.

[0013] The liquid fertilizer production apparatus of the present invention preferably has a control unit, a membrane separation unit, and an electrodialysis unit, and further has a measurement unit described below. In addition to these, the liquid fertilizer production apparatus may have equipment incidental to a general liquid fertilizer production apparatus.

[0014] 1 shows, as the equipment related to the present invention, control units 24, 26, 28, a membrane separation unit 20, an electrodialysis unit 40, and measurement units 29, 43. Also, as the equipment that the membrane separation unit 20 may be equipped with, a liquid temperature regulator 23, a pH regulator 25, and a flow rate regulator 27 are shown. In addition, as general equipment, a digestive fluid tank 10, a treated water tank 30, a first flow path 11, a second flow path 21, a third flow path 31, etc. are shown.

[0015] As mentioned above, inorganic nitrogen is broadly classified into (1) ammonium nitrogen, and (2) nitrate nitrogen and nitrite nitrogen. The liquid fertilizer produced in the present invention is a liquid fertilizer containing the inorganic nitrogen, and can contain (1) ammonia nitrogen, and (2) nitrate nitrogen and nitrite nitrogen in any composition ratio. Here, nitrate nitrogen refers to nitric acid or nitrates. In addition, any composition ratio means various composition ratios required depending on the growing conditions and types of plants, that is, the target composition ratio of inorganic nitrogen. The liquid fertilizer of the present invention can contain the inorganic nitrogen at any concentration.

[0016] <Digestive fluid> The digestive fluid used in the present invention is a digestive fluid of organic matter, and is a liquid obtained after fermentation of organic matter such as human waste. The digestive liquid includes digestive liquid from anaerobic fermentation and digestive liquid from aerobic fermentation. The digestive liquid from anaerobic fermentation is a liquid fermented under oxygen-free conditions with air blocked off. The digestive liquid from aerobic fermentation is a liquid fermented under air aeration conditions.

[0017] <Control Unit> The control unit of the present invention sets the operating conditions in accordance with the target composition ratio of inorganic nitrogen. In the present invention, since it is mainly the membrane separation section that adjusts the composition ratio of inorganic nitrogen, the control section sets the operating conditions of the membrane separation section in accordance with the target composition ratio of inorganic nitrogen.

[0018] When the membrane bioreactor described below is equipped with a flow rate regulator, the control unit measures the flow rate of the separated liquid and sets the operating conditions of the flow rate regulator. Hereinafter, this control unit may be referred to as the "control unit (flow rate)."

[0019] When the membrane bioreactor described below is equipped with a liquid temperature regulator, the control unit measures the treatment temperature of the digestive liquid and sets the operating conditions of the liquid temperature regulator. Hereinafter, this control unit may be referred to as the "control unit (liquid temperature)."

[0020] When the membrane bioreactor described below is equipped with a pH adjusting device, the control unit measures the treated pH of the digestive liquid and sets the operating conditions of the pH adjusting device. Hereinafter, this control section may be referred to as the "control section (pH)." The control section may be used alone or in combination of two or more types.

[0021] <Membrane separation section> The membrane separation unit of the present invention biologically treats the digestive liquid and performs membrane separation in accordance with the settings of the control unit. The membrane separation section may have any function as long as it can biologically treat the digestive liquid and perform membrane separation, and a specific example thereof is a membrane bioreactor. The membrane bioreactor is also called a "membrane separation activated sludge process."

[0022] The membrane bioreactor used in the present invention uses a treatment tank containing treated water and activated sludge, and a membrane such as a microfiltration membrane or an ultrafiltration membrane. In the membrane bioreactor, the digestive liquid is treated with activated sludge, whereby nitrification by aerobic bacteria progresses and ammonia nitrogen is converted into nitrate nitrogen and nitrite nitrogen. The treated digestive liquid is filtered through the membrane, and the separated liquid that permeates the membrane is sent to the electrodialysis section. Hereinafter, "membrane bioreactor" may be referred to as "MBR."

[0023] <Electrodialysis section> The electrodialysis unit of the present invention concentrates the separated liquid filtered in the membrane separation unit. As the electrodialysis unit, a known electrodialysis device may be used. An example of the electrodialysis device is DW-1 manufactured by AGC Engineering Co., Ltd.

[0024] An electrodialysis device is a device in which multiple sets of cation exchange membranes and anion exchange membranes are stacked alternately with spacers between them, with a pair of electrodes placed at both ends, and deionization chambers (chamber D), which are spaces separated by anion exchange membranes on the anode side and cation exchange membranes on the cathode side, and concentration chambers (chamber C), which are spaces separated by cation exchange membranes on the anode side and anion exchange membranes on the cathode side, are arranged alternately. When the stock solution is supplied to compartment D, the cations pass through the cation exchange membrane toward the cathode and move to compartment C, which is closer to the cathode. However, because the cathode side of compartment C is separated by an anion exchange membrane, the cations cannot move further to the adjacent compartment D. Similarly, anions move from compartment D to compartment C on the anode side. As a result, they are desalted in compartment D and concentrated in compartment C.

[0025] In the electrodialysis section, the separated liquid to be treated is separated into an electrodialysis concentrate and an electrodialysis desalted liquid. The electrodialysis concentrate has a higher salt concentration than the separated liquid before treatment, and the electrodialysis desalted liquid has a lower salt concentration than the separated liquid before treatment. The function of the electrodialysis section is as described above, and although it can concentrate inorganic nitrogen, it does not actively adjust the composition ratio of inorganic nitrogen.

[0026] <Measurement section> The liquid fertilizer manufacturing apparatus of the present invention may further include a measurement unit that measures a composition ratio of the separated liquid. The separated liquid herein refers to a liquid that has been treated with the activated sludge and filtered through a membrane such as a microfiltration membrane or an ultrafiltration membrane, and the composition ratio refers to the composition ratio of inorganic nitrogen contained in the separated liquid. The measuring unit may be installed at any position as long as it can measure the composition ratio of the separated liquid. Explaining with reference to Fig. 1, it may be installed in the second flow path 21 leading from the membrane separation unit 20 to the next process as in measuring unit 29, or it may be installed in the electrodialysis concentrate flow path 42 as in measuring unit 43.

[0027] The measuring section may be any device capable of measuring the composition ratio of inorganic nitrogen in the separated liquid, and may be an automatic measuring device or a manual measuring device.

[0028] <Setting / controlling operating conditions> The operating conditions set by the control unit include, for example, the residence time of the digestive liquid in the MBR, the treatment temperature of the digestive liquid in the MBR, and the treatment pH of the digestive liquid in the MBR. Here, the residence time of the digestive liquid in the MBR can be adjusted by the flow rate of the separated liquid in the MBR. By adjusting these operating conditions of the MBR, it is possible to adjust the degree to which ammonia nitrogen is converted into nitrate nitrogen and nitrite nitrogen, i.e., the composition ratio of inorganic nitrogen can be adjusted. However, because MBR treatment does not convert nitrate nitrogen and nitrite nitrogen into ammonia nitrogen, the composition ratio of ammonia nitrogen cannot be made higher than that of the digestive liquid, which is the water to be treated.

[0029] If the retention time of the digested liquid in the MBR is increased, nitrification will progress, and the ratio of ammonia nitrogen will tend to decrease and the ratios of nitrate nitrogen and nitrite nitrogen will tend to increase. If the treatment temperature of the digested liquid in an MBR is appropriate, nitrification will proceed, and the ratio of ammonia nitrogen will tend to decrease and the ratios of nitrate nitrogen and nitrite nitrogen will tend to increase. If the treatment pH of the digested liquid in the MBR is appropriate, nitrification will proceed, and the ratio of ammonia nitrogen will tend to decrease and the ratios of nitrate nitrogen and nitrite nitrogen will tend to increase.

[0030] The appropriate range of operating conditions for the MBR described above varies depending on the type and condition of the activated sludge used in the MBR and the characteristics of the digestive liquid used. For this reason, it is necessary to confirm the appropriate range of operating conditions in advance at the laboratory level, or to confirm the appropriate range of operating conditions by operating the actual equipment. The operating conditions may be appropriately set according to the appropriate range confirmed by the above method.

[0031] When it is confirmed by the measurement value of the measurement unit that the composition ratio of inorganic nitrogen obtained under the set operating conditions is different from the target composition ratio of inorganic nitrogen, each control unit resets the operating conditions. In this case, a program may be prepared in advance to monitor the values ​​measured by the measuring units intermittently or continuously, and feed that information back to each control unit so that each control unit can reset the operating conditions.

[0032] In order to realize the operating conditions set by the control unit, the MBR is preferably equipped with a flow rate regulator, a liquid temperature regulator, and a pH regulator. These may be used alone or in combination of two or more. Providing multiple adjustment devices makes it easier to adjust the composition ratio of inorganic nitrogen.

[0033] When the operating conditions are set based on the residence time of the digestion liquid in the MBR, the MBR is equipped with a flow rate regulator, and the control unit (flow rate) measures the flow rate of the separated liquid and sets the operating conditions of the flow rate regulator. The flow rate regulator adjusts the residence time of the digestion liquid in the MBR according to the setting of the control unit (flow rate). If it is confirmed that the obtained composition ratio of inorganic nitrogen is different from the target value, the control unit (flow rate) resets the operating conditions of the flow rate regulator. The flow rate adjusting device may be a known device capable of adjusting the flow rate, and the control unit (flow rate) may be a known system capable of controlling the flow rate.

[0034] When the operating conditions are set based on the treatment temperature of the digestive liquid in the MBR, the MBR is equipped with a liquid temperature regulator, and the control unit (liquid temperature) measures the treatment temperature of the digestive liquid and sets the operating conditions of the liquid temperature regulator. The liquid temperature regulator regulates the treatment temperature of the digestive liquid in the MBR according to the setting of the control unit (liquid temperature). If it is confirmed that the obtained composition ratio of inorganic nitrogen is different from the target value, the control unit (liquid temperature) resets the operating conditions of the liquid temperature adjustment device. The liquid temperature adjusting device may be a known device capable of adjusting the liquid temperature, and the control unit (liquid temperature) may be a known system capable of controlling the liquid temperature.

[0035] When the operating conditions are set based on the treatment pH of the digestive liquid in the MBR, the MBR is equipped with a pH regulator, and the control unit (pH) measures the treatment pH of the digestive liquid and sets the operating conditions of the pH regulator. The pH regulator adjusts the treatment pH of the digestive liquid in the MBR according to the setting of the control unit (pH). If it is confirmed that the obtained composition ratio of inorganic nitrogen is different from the target value, the control unit (pH) resets the operating conditions of the pH adjustment device. The pH adjusting device may be a known device capable of adjusting pH, and the control unit (pH) may be a known system capable of controlling pH. The use of nitric acid when adjusting the treatment pH of the digested liquid in the MBR is preferable because nitric acid itself is inorganic nitrogen and can be effectively used as a component of liquid fertilizer.

[0036] <Liquid fertilizer manufacturing method> The method for producing a liquid fertilizer of the present invention is a method for producing a liquid fertilizer containing inorganic nitrogen, and includes the following steps (1) to (3): Step (1): A control step of setting operating conditions in accordance with the target composition ratio of inorganic nitrogen; Step (2): A membrane separation step of biologically treating the digestive liquid of organic matter according to the settings of the control step; Step (3): An electrodialysis step for concentrating the separated liquid filtered in the membrane separation step.

[0037] <Process (1)> Step (1) is a control step for setting operating conditions in accordance with a target composition ratio of inorganic nitrogen, and its gist is the same as that of the "control unit" explained in the section on the liquid fertilizer manufacturing apparatus. On the other hand, as is clear from the fact that process (1) is referred to as a control process and not a control unit, the control unit does not refer to a specific piece of equipment, but includes the controlling operation and the act of controlling.

[0038] <Process (2)> Step (2) is a membrane separation step in which the digestive liquid of organic matter is biologically treated according to the settings of the control step, and its gist is the same as that of the "membrane separation section" explained in the section on the liquid fertilizer manufacturing equipment. On the other hand, as is clear from the fact that it is referred to as the membrane separation process rather than the membrane separation section in step (2), the membrane separation process does not refer to a specific piece of equipment called the membrane separation section, but includes the operation and act of membrane separation.

[0039] <Process (3)> Step (3) is an electrodialysis step for concentrating the separated liquid filtered in the membrane separation step, and its gist is the same as that of the "electrodialysis section" explained in the section on the liquid fertilizer production apparatus. On the other hand, as is clear from the fact that it is referred to as an electrodialysis process rather than an electrodialysis unit in step (3), the term "electrodialysis process" does not refer to a specific facility called an electrodialysis unit, but includes the operation and act of electrodialysis.

[0040] <Process (4)> The liquid fertilizer production method of the present invention may further include the following step (4): Step (4): A measuring step of measuring the composition ratio of the separated liquid. The purpose of step (4) is the same as that of the "measuring unit" explained in the section on the liquid fertilizer manufacturing apparatus. On the other hand, as is clear from the fact that it is referred to as the measurement process rather than the measurement unit in step (4), the measurement process does not refer to a specific piece of equipment called the measurement unit, but includes the operation and act of measuring.

[0041] The reasons why the following is preferable are the same as those explained in the section on the liquid fertilizer manufacturing apparatus, and details will be omitted. In the liquid fertilizer producing method of the present invention, it is preferable to reset the operating conditions in the control step based on the measured values ​​in the measurement step. The membrane separation step in step (2) is preferably a step using an MBR. It is preferable that the MBR has a flow rate adjustment function, and the operating conditions of the flow rate adjustment function are set in the control step. It is preferable that the MBR has a liquid temperature adjustment function, and the operating conditions of the liquid temperature adjustment function are set in the control step. It is preferable that the MBR has a pH adjustment function and that the operating conditions of the pH adjustment function are set in the control step. It is also preferable that nitric acid is used to adjust the pH of the MBR.

[0042] <Liquid fertilizer> The liquid fertilizer of the present invention is obtained by the liquid fertilizer production apparatus or the liquid fertilizer production method of the present invention, and contains inorganic nitrogen. In addition to the inorganic nitrogen, the liquid fertilizer may contain other additives that are common in fertilizers. It is also possible to add inorganic nitrogen later to adjust the composition ratio of inorganic nitrogen depending on the individual use situation.

[0043] <Application> The liquid fertilizer of the present invention can be used as a general fertilizer, but is particularly suitable for use as a base fertilizer or top dressing in soil culture or hydroponic culture depending on the growing conditions and type of plant. EXAMPLES

[0044] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the following examples and comparative examples, various physical properties were measured by the following methods.

[0045] [Evaluation method] (1) Ammonia nitrogen concentration Analysis was performed using the Nessler method using an HCAH DR2700 spectrophotometer.

[0046] (2) Concentrations of nitrate nitrogen and nitrite nitrogen Measurements were performed by ion chromatography using Tosoh's "IC-2100." The column was a Tosoh TSKgel SuperIC-A HS, and a mixture of NaHCO3 and NaCO3 was used as the mobile phase, and detection was performed by electrical conductivity.

[0047] [Example 1] The raw water used was Chikujo Town digestive fluid, which is a digestive fluid of organic matter and is an aerobic fermentation digestive fluid derived from human waste. The membrane separation section is equipped with an ultrafiltration membrane manufactured by Mitsubishi Chemical Corporation (membrane material: polyvinylidene fluoride, nominal pore size: 0.05 μm, membrane shape: hollow fiber), and has a volume of 2 m 3 An aquarium was used. The digestive fluid was poured into a water tank, and the ultrafiltration membrane was immersed in the digestive fluid. At this time, the temperature of the digestive fluid (treatment temperature) was 25°C. In this state, continuous suction filtration was performed, and the separated liquid was separated into the separated liquid filtered by the ultrafiltration membrane and the dispersion liquid containing the unfiltered sludge. The flow rate of the separated liquid was 60 L / h. The residence time of the digested liquid was 33 hours. The separated liquid obtained was stored in a treated water tank.

[0048] The separated liquid was treated with an electrodialysis device "DW-1 type" (cation ion exchange membrane: CMVN, anion ion exchange membrane: AMVN) manufactured by AGC Engineering Co., Ltd. The electrodialysis voltage was set to 15 V, and the separated liquid was separated into an electrodialysis concentrated liquid and an electrodialysis desalted liquid. The electrodialysis desalted liquid is 1.1m 3 The treated water was returned to the treated water tank at a flow rate of 1000 ml / h, and circulation was performed. The electrodialysis concentrate thus obtained was subjected to measurement of the concentrations of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen. The results are shown in Table 1.

[0049] [Example 2] An electrodialysis concentrate was obtained in the same manner as in Example 1, except that the flow rate of the separated liquid was 30 L / h and the residence time of the digested liquid was 67 hours. The results are shown in Table 1.

[0050] [Example 3] An electrodialysis concentrate was obtained in the same manner as in Example 1, except that the liquid temperature (treatment temperature) of the digested liquid was set to 10°C. The results are shown in Table 1.

[0051] [Table 1]

[0052] As is clear from Table 1, the production method of the present invention (Examples 1 to 3) was able to adjust the composition ratio of ammonia nitrogen / nitrate nitrogen and nitrite nitrogen in the electrodialysis concentrate by setting the operating conditions. This allows the present invention to easily produce a liquid fertilizer with an adjusted composition ratio of inorganic nitrogen components. [Explanation of symbols]

[0053] 10 digestive fluid tank, 11 first flow path 20 Membrane separation section (MBR), 21 Second flow path, 22 Sludge extraction flow path 23 Liquid temperature regulator, 24 control unit (liquid temperature), 25 pH regulator, 26 control unit (pH), 27 flow regulator, 28 control unit (flow), 29 measurement unit 30 treated water tank, 31 third flow path 40 electrodialysis section, 41 electrodialysis desalted liquid flow path, 42 electrodialysis concentrated liquid flow path, 43 measurement section

Claims

1. A liquid fertilizer manufacturing apparatus for producing liquid fertilizer containing inorganic nitrogen, A control unit that sets operating conditions according to the target composition ratio of inorganic nitrogen; A membrane separation unit that biologically treats the organic digestive liquid and separates it into membranes according to the settings of the control unit; an electrodialysis section for concentrating the separated liquid filtered by the membrane separation section; A measurement unit that measures the composition ratio of the separated liquid, A liquid fertilizer manufacturing apparatus, wherein the control unit resets one or more operating conditions among the treatment temperature of the digested liquid, the treatment pH of the digested liquid, and the flow rate of the separated liquid based on the measured value of the composition ratio of the inorganic nitrogen by the measurement unit.

2. A liquid fertilizer manufacturing apparatus as described in claim 1, wherein the composition ratio of the separated liquid is the ratio of ammonia nitrogen to the sum of nitrate nitrogen and nitrite nitrogen in the separated liquid.

3. A liquid fertilizer manufacturing apparatus as described in claim 1 or 2, wherein the control unit reduces the flow rate of the separated liquid when attempting to reduce the ratio of ammonia nitrogen toward a target composition ratio based on the measured value of the inorganic nitrogen composition ratio.

4. A liquid fertilizer manufacturing apparatus as described in claim 1 or 2, wherein the control unit increases the treatment temperature of the digestive liquid when attempting to reduce the ratio of ammonia nitrogen toward a target composition ratio based on the measured value of the inorganic nitrogen composition ratio.

5. A liquid fertilizer manufacturing apparatus as described in claim 1 or 2, wherein the control unit reduces the flow rate of the separated liquid and increases the treatment temperature of the digested liquid when attempting to reduce the ratio of ammonia nitrogen toward a target composition ratio based on the measured value of the inorganic nitrogen composition ratio.

6. The liquid fertilizer production apparatus according to claim 1 or 2, wherein the membrane separation section is a membrane bioreactor.

7. The liquid fertilizer production apparatus according to claim 6 , wherein the membrane bioreactor is provided with a flow rate regulator, and the control unit sets operating conditions of the flow rate regulator.

8. The liquid fertilizer production apparatus according to claim 6 , wherein the membrane bioreactor is provided with a liquid temperature adjustment device, and the control unit sets operating conditions of the liquid temperature adjustment device.

9. The liquid fertilizer production apparatus according to claim 6 , wherein the membrane bioreactor is provided with a pH adjusting device, and the control unit sets operating conditions of the pH adjusting device.

10. A liquid fertilizer production method for producing a liquid fertilizer containing inorganic nitrogen, comprising: Step (1): A control step of setting operating conditions according to a target composition ratio of the inorganic nitrogen; Step (2): A membrane separation step of biologically treating and membrane-separating the organic digestive liquid according to the setting of the control step; Step (3): An electrodialysis step of concentrating the separated liquid filtered in the membrane separation step; Step (4): A measuring step of measuring the composition ratio of the separated liquid, A liquid fertilizer production method, in which in the control step, one or more operating conditions among the treatment temperature of the digested liquid, the treatment pH of the digested liquid, and the flow rate of the separated liquid are adjusted based on the measured value of the composition ratio of the inorganic nitrogen in the measurement step.

11. A liquid fertilizer manufacturing method as described in claim 10, wherein the composition ratio of the separated liquid is the ratio of ammonia nitrogen to the sum of nitrate nitrogen and nitrite nitrogen in the separated liquid.

12. A liquid fertilizer manufacturing method as described in claim 10 or 11, wherein in the control process, the flow rate of the separated liquid is reduced when attempting to reduce the ratio of ammonia nitrogen toward a target composition ratio based on the measured value of the inorganic nitrogen composition ratio.

13. A liquid fertilizer manufacturing method as described in claim 10 or 11, wherein in the control process, when attempting to reduce the ratio of ammonia nitrogen toward a target composition ratio based on the measured value of the inorganic nitrogen composition ratio, the treatment temperature of the digested liquid is increased.

14. A liquid fertilizer manufacturing method as described in claim 10 or 11, wherein in the control process, when attempting to reduce the ratio of ammonia nitrogen toward a target composition ratio based on the measured value of the composition ratio of inorganic nitrogen, the flow rate of the separated liquid is reduced and the treatment temperature of the digested liquid is increased.

15. The method for producing a liquid fertilizer according to claim 10 or 11, wherein the membrane separation step is a step using a membrane bioreactor.

16. The liquid fertilizer producing method according to claim 15, wherein the membrane bioreactor has a flow rate adjusting function, and the control step sets operating conditions for the flow rate adjusting function.

17. The liquid fertilizer producing method according to claim 15, wherein the membrane bioreactor has a liquid temperature adjustment function, and the control step sets operating conditions for the liquid temperature adjustment function.

18. The liquid fertilizer producing method according to claim 15, wherein the membrane bioreactor has a pH adjustment function, and the control step sets operating conditions for the pH adjustment function.

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