Ammonia removal apparatus and ammonia removal method

Abstract

To provide an ammonia removal apparatus that is relatively small in size, energy-saving, and inexpensive in terms of both construction cost and operation cost, and an ammonia removal method using the same.SOLUTION: An ammonia removal apparatus and an ammonia removal method use a mesh fiber disc made of polyvinylidene chloride fibers as a carrier, and form a high-concentration microbial membrane dominated by Bacillus bacteria on this mesh fiber disc. Furthermore, by rotating this mesh fiber disc inside a treatment tank, nitrification and denitrification of ammonia nitrogen are performed almost simultaneously in a single tank. This enables the apparatus to be compact in scale, thereby achieving space saving and reduced construction cost. In addition, since the inside of the treatment tank is brought into an aerobic state by the rotation of the mesh fiber disc, the operation cost (electric power cost) can be kept low with energy saving. Furthermore, by removing ammonia nitrogen from the waste liquid, the treated water can be used as a fertilizer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ammonia removal apparatus for converting ammonia nitrogen in wastewater into nitrogen gas and removing it, and an ammonia removal method using this ammonia removal apparatus. [Background technology]

[0002] In recent years, there has been a demand to reduce carbon dioxide emissions, which are believed to be a cause of global warming. One method of reducing carbon dioxide emissions is the use of biomass fuels. Biomass fuels are fuels produced from plants that have absorbed carbon dioxide through photosynthesis, as well as from the excrement of animals that eat these plants, food waste, etc., and are said to produce no substantial increase in the amount of carbon dioxide when burned.

[0003] In addition, dairy farming and livestock farming generate large amounts of livestock waste, including livestock and poultry excrement and bedding. Systems that ferment this livestock waste to obtain methane gas and use it to generate electricity can reduce commercial electricity consumption and sell the surplus electricity. They also use the waste heat and hot water generated during power generation as a heat source for livestock and agricultural facilities. Furthermore, the digestate, the residue after methane fermentation, contains a high organic carbon content and decomposes slowly, making it suitable for use as fertilizer. However, this digestate contains high concentrations of harmful ammonia nitrogen, which, if used as fertilizer, could impair crop growth and potentially seep underground and contaminate groundwater. Furthermore, if it flows out to the surface, it could disrupt the ecosystems of the rivers it flows into and contaminate the water quality. Therefore, the ammonia nitrogen must be removed before it can be used as fertilizer.

[0004] Here, Patent Document 1 below is an example of a method for removing ammonia from wastewater. Another common method for removing ammonia nitrogen from wastewater is the nitrification-denitrification method using activated sludge. In this activated sludge method, the wastewater is first aerated to create aerobic conditions, and the ammonia nitrogen in the liquid is converted to nitrate nitrogen by nitrifying bacteria in the activated sludge (nitrification). Next, the wastewater is placed under anaerobic conditions, and the microorganisms in the activated sludge use the oxygen in the nitrate nitrogen to oxidize and decompose the organic matter. As a result, the nitrogen component in the nitrate nitrogen is converted into nitrogen gas and released into the air (denitrification). When the wastewater is digested liquid, the organic matter required for denitrification is often not present in a decomposable form. Therefore, denitrification is usually performed by adding easily decomposable organic matter, such as methanol. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-135031 Summary of the Invention [Problem to be solved by the invention]

[0006] However, these conventional methods for removing ammonia nitrogen using activated sludge have the problem of high operating costs (electricity costs) due to the large amount of oxygen required for aeration during the nitrification process, which requires powerful blowers with high power consumption. For example, in methane gas power generation using livestock waste, a significant amount of electricity is consumed to remove ammonia from the digester liquid, significantly reducing the commercial electricity consumption and carbon dioxide reduction benefits of biomass power generation. Furthermore, at least two tanks are required for nitrification and denitrification, and in the case of cyclic denitrification, at least four tanks are required: first and second nitrification tanks and first and second denitrification tanks. This results in large equipment scale and high construction costs. Furthermore, the cost of organic materials such as methanol added during denitrification is also required.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide an ammonia removal apparatus that is relatively small in apparatus scale, energy-saving, and low in both construction cost and operation cost, and an ammonia removal method using the same.

Means for Solving the Problems

[0008] The present invention (1) A storage tank 20 for storing wastewater containing ammonia nitrogen, an ammonia removal tank 50 for decomposing ammonia nitrogen in the wastewater and discharging it as nitrogen gas, and a sedimentation tank 22 for solid-liquid separation of the treated water after ammonia nitrogen removal, and the ammonia removal tank 50 A net-like fiber disk 52 formed by making fibers of polyvinylidene chloride into a net shape and molding it into a disk shape, a holding part 54 for holding a plurality of the net-like fiber disks 52 coaxially and holding them in the tank so that the lower part is immersed in the wastewater, and a rotating part 56 for rotating the net-like fiber disk 52 together with the holding part 54. By providing an ammonia removal apparatus 80 having the above, the above problems are solved. (2) By further providing a treatment water tank 24 for obtaining the separated liquid which is the supernatant of the sedimentation tank 22 and storing it as liquid fertilizer, the ammonia removal apparatus 80 according to the above (1) is provided, and the above problems are solved. (3) By further providing a dehydration part 26 for dehydrating the sediment deposited in the sedimentation tank 22, a slag removal part 28 for collecting impurities in the wastewater before the ammonia removal tank 50, and a compost generation part 30 for composting the dehydrated sediment dehydrated by the dehydration part 26 and the impurities collected by the slag removal part 28, the ammonia removal apparatus 80 according to the above (1) is provided, and the above problems are solved. (4) A seeding step S102 of seeding Bacillus bacteria on a net-like fiber disk 52 formed by making fibers of polyvinylidene chloride into a net shape and molding it into a disk shape, A dominant optimization step S104 of growing and dominant-optimizing the Bacillus bacteria on the net-like fiber disk 52, While rotating the lower part of the reticulated fiber disk 52 while holding it in the tank so that it is immersed in the wastewater containing ammonia nitrogen, the nitrifying bacteria on the surface layer of the microbial film attached to the reticulated fiber disk 52 under aerobic conditions convert the ammonia nitrogen in the wastewater into nitrate nitrogen, and the Bacillus bacteria in the inner layer of the microbial film under anaerobic conditions consume the oxygen in the nitrate nitrogen and decompose and release it into nitrogen gas, thereby providing an ammonia removal method characterized by having an ammonia removal step S106, and solving the above problems. (5) A solid-liquid separation step S108 of solid-liquid separating the treated water after ammonia nitrogen removal by a sedimentation method, and a liquid fertilizer acquisition step S110 of using the separated liquid, the supernatant, as liquid fertilizer, thereby providing the ammonia removal method according to the above (4), and solving the above problems. (6) A collection step S103 of collecting impurities in the wastewater before the ammonia removal step, A dehydration step S112 of dehydrating the sediment separated by solid-liquid separation, And a composting step S114 of composting the dehydrated sediment dehydrated in the dehydration step and the impurities collected in the collection step, thereby providing the ammonia removal method according to the above (5), and solving the above problems.

Effects of the Invention

[0009] The ammonia removal device and ammonia removal method according to the present invention use a reticulated fiber disk composed of polyvinylidene chloride fibers as a carrier, and form a high-concentration microbial film body in which Bacillus bacteria are dominant on this reticulated fiber disk. Then, by rotating this reticulated fiber disk in the treatment tank, nitrification and denitrification of ammonia nitrogen can be carried out almost simultaneously in one tank. Thereby, the scale of the device can be made compact, and space saving and reduction of construction costs can be achieved. In addition, the ammonia removal device and the ammonia removal method according to the present invention make the inside of the treatment tank aerobic by rotating the reticulated fiber disk. Therefore, aeration by a blower that consumes a large amount of power is not required, and energy can be saved and the operating cost (power cost) can be kept low. Furthermore, by removing ammonia nitrogen from the waste liquid, the treated water can be used as fertilizer.

Brief Description of the Drawings

[0010] [Figure 1] It is a schematic configuration diagram of the ammonia removal device according to the present invention. [Figure 2] It is a schematic configuration diagram of the ammonia removal tank constituting the present invention. [Diagram 3] It is a process flowchart of the ammonia removal method according to the present invention. [Figure 4] It is a graph of the experimental results of the ammonia removal tank and the ammonia removal process of the present invention.

Embodiments for Carrying Out the Invention

[0011] Embodiments of the ammonia removal device 80 and the ammonia removal method according to the present invention will be described with reference to the drawings. Here, FIG. 1 is a schematic configuration diagram of the ammonia removal device 80 according to the present invention. The waste liquid to be treated by the present invention includes not only the digested liquid after methane fermentation of livestock waste, but also the digested liquid after methane fermentation using raw garbage, food waste, paper waste, organic matter derived from animals and plants, and others as raw materials, sludge treatment return water in sewage and other water treatment facilities, etc. It is applicable to all waste liquids containing ammonia nitrogen.

[0012] First, the ammonia removal apparatus 80 according to the present invention includes a storage tank 20 for storing wastewater containing ammonia nitrogen, an ammonia removal tank 50 for decomposing the ammonia nitrogen in the wastewater and releasing it as nitrogen gas, and a settling tank 22 for performing solid-liquid separation of the treated water after ammonia nitrogen removal. Furthermore, when the wastewater contains relatively large impurities such as garbage or plant fragments, it is preferable to provide a residue removal unit 28 for collecting the impurities in the wastewater upstream of the ammonia removal tank 50, i.e., between the storage tank 20 and the ammonia removal tank 50. The residue removal unit 28 is not particularly limited, and any known member capable of separating and collecting impurities of a predetermined size or larger can be used, such as a net or slit with a predetermined mesh size, a sieve, or a belt screen.

[0013] The impurities collected in the residue removal section 28 are preferably composted in the composting section 30. The composting section 30 is not particularly limited, and in addition to compost, any known composting device such as a commercially available composting machine can be used.

[0014] The settling tank 22 allows the treated water from the ammonia removal tank 50 to stand and separates the solids and liquids, and may be, for example, a well-known settling tank with a generally conical hopper at the bottom. The supernatant liquid, which is the supernatant liquid obtained after solid-liquid separation in the settling tank 22, is stored in the treated water tank 24. In particular, when digested liquid made from livestock waste is used as the waste liquid, the supernatant liquid is rich in phosphoric acid and potassium, which are necessary for plant growth, as well as organic nitrogen, which is not decomposed in the ammonia removal tank 50. For this reason, the supernatant liquid can be used as liquid fertilizer as is.

[0015] In addition, the precipitate deposited in the sedimentation tank 22 is appropriately removed and sent to the dehydration unit 26. Then, the precipitate is dehydrated in this dehydration unit 26. Note that the dehydration unit 26 is not particularly limited, and well-known dehydrators such as a filter press or a belt press can be used. Further, it is preferable that the dehydrated precipitate dehydrated in the dehydration unit 26 is sent to the compost production unit 30 described above for composting. In addition, since the drainage during dehydration can be used as liquid fertilizer in the same manner as the desorbed liquid of the sedimentation tank 22, it is preferably refluxed to the storage tank 20 or the slag removal unit 28.

[0016] Next, the ammonia removal tank 50, which is a characteristic configuration of the present invention, will be described. Here, FIG. 2 is a schematic configuration diagram of the ammonia removal tank 50 constituting the present invention. In FIG. 2, the treatment tank 40 is shown in a transparent state with a broken line. First, the ammonia removal tank 50 of the present invention includes a treatment tank 40 having a substantially cylindrical upper portion, a net-like fiber disk 52 accommodated in the treatment tank 40, a holding portion 54 that holds a plurality of the net-like fiber disks 52 coaxially in the treatment tank 40, and a rotating portion 56 that rotates the net-like fiber disk 52 together with the holding portion 54. Note that a weak aeration device may be provided at the bottom of the treatment tank 40 to peel off the excessive microbial film attached to the net-like fiber disk 52. The peeled microbial film is sent to the sedimentation tank 22 together with the treated water from which ammonia nitrogen has been removed.

[0017] Here, as the net-like fiber disk 52, a fiber of polyvinylidene chloride is formed into a three-dimensional non-woven net and molded into a disk shape. Note that the polyvinylidene chloride fiber to be used is preferably about 3500 denier to 4500 denier. In addition, the bulk density of the net-like fiber disk 52 is 45 kg / m 3 ~65 kg / m 3 and the specific surface area is 100 m 2 / m 3 ~300 m 2 / m 3, it is preferable to use those with a space ratio of 95% to 98%. Here, polyvinylidene chloride has a high affinity with microorganisms having a sewage purification function including Bacillus bacteria. For this reason, in the reticulated fiber disk 52 formed with the fibers of polyvinylidene chloride as a three-dimensional network, the purification microorganisms form a three-dimensional microbial film body that fills the voids of the network using these reticulated fibers as a carrier. This three-dimensional microbial film body has a specific surface area several times larger than that of the planar microbial film formed on the conventional plate-shaped carrier, and has an extremely large amount and high concentration of microbial film. For this reason, it has a purification ability (nitrification ability, denitrification ability) superior to that of the prior art.

[0018] Further, the holding part 54 holds a plurality of reticulated fiber disks 52 as described above and has a rotating shaft. The rotating shaft is fixed so as to penetrate the center of each reticulated fiber disk 52, and a plurality of reticulated fiber disks 52 are arranged coaxially and held, and are rotatably supported at a predetermined height position in the treatment tank 40. Further, a supply pipe 40a for supplying wastewater from the storage tank 20 (debris removal part 28) and a water supply pipe 40b for sending the treated water in the treatment tank 40 to the sedimentation tank 22 are connected to the treatment tank 40. Further, the water level of the wastewater in the treatment tank 40 is maintained below the reticulated fiber disk 52, generally to the extent that it does not touch the rotating shaft of the holding part 54. As a result, the lower part of the reticulated fiber disk 52 is immersed in the wastewater, and the upper part is exposed above the water surface.

[0019] Further, the rotating part 56 is a well-known rotating mechanism such as a motor, and rotates the reticulated fiber disk 52 in the treatment tank 40 by rotating the rotating shaft of the holding part 54. Since the reticulated fiber disk 52 is held at a position where the lower part is immersed in the wastewater as described above, the immersion position of the reticulated fiber disk 52 changes at a constant speed as the rotating part 56 rotates.

[0020] Next, the ammonia removal method according to the present invention will be described. Here, FIG. 3 is a process flowchart of the ammonia removal method according to the present invention. In FIG. 3, an example will be described in which the digested liquid after methane fermentation of livestock waste is used as the wastewater containing ammonia nitrogen, and the desorbed liquid after ammonia removal is used as liquid fertilizer and the solid matter is used as compost.

[0021] First, when the reticulated fiber disks 52 in the ammonia removal tank 50 are new, they are seeded with Bacillus bacteria (for example, Bacillus subtilis) (seeding step S102). As mentioned above, Bacillus bacteria have a high affinity for polyvinylidene chloride, so by seeding, the Bacillus bacteria adhere to the fiber surface and grow, achieving a sufficient bacterial cell density.

[0022] Concurrently, wastewater containing ammonia nitrogen, such as digested liquid obtained after methane fermentation of livestock waste, is stored in storage tank 20. Next, the wastewater is poured into treatment tank 40. At this time, it is preferable to collect impurities in the wastewater using residue removal unit 28 (collection step S103). The impurities collected by residue removal unit 28 are preferably sent to compost generation unit 30 and composted.

[0023] When the wastewater reaches a predetermined water level in the treatment tank 40, the lower part of the reticular fiber disk 52 is submerged to a predetermined position. Next, the rotating unit 56 is rotated at a speed of 1 rpm to 10 rpm. The residence time of the wastewater in the ammonia removal tank 50 is approximately 10 hours to 50 hours, depending on the concentration of ammonia nitrogen in the wastewater and the capacity of the ammonia removal tank 50. As a result, various purification microorganisms, including Bacillus bacteria, attach to and grow on the reticular fiber disk 52, filling the voids in the mesh and forming a microbial film. Since Bacillus bacteria have a particularly fast growth rate among these purification microorganisms, pre-seeding them in step S102 maintains a sufficient bacterial density within the microbial film and allows them to become dominant in the microbial film formed on the reticular fiber disk 52 (dominance step S104). Bacillus bacteria are characterized by their ability to decompose a variety of organic matter and their fast decomposition rate, resulting in excellent denitrification performance. It also has a high affinity with nitrifying bacteria and does not inhibit the nitrification of ammonia nitrogen. Furthermore, it has a high antagonistic effect on sulfate-reducing bacteria, suppressing the production of hydrogen sulfide by sulfate-reducing bacteria and preventing the generation of foul odors.

[0024] In addition, in the ammonia removal tank 50 of the present invention, air is taken into the waste liquid in the treatment tank 40 by the rotation of the net-like fiber disk 52 to create aerobic conditions. The power consumption of the rotating part 56 at this time is 1 / 10 or less of the power consumption of the blower in the method using activated sludge. Therefore, the ammonia removal device 80 and the ammonia removal method according to the present invention can operate with less power consumption than the conventional method using activated sludge, and even when methane gas power generation is performed, the effects of saving commercial power generated by biomass power generation and reducing carbon dioxide can be fully enjoyed.

[0025] And as described above, due to the rotation of the net-like fiber disk 52, the surface layer of the microbial film body is in an aerobic state. However, oxygen does not reach the inner side of the microbial film body, and it is basically in an anaerobic state. As a result, nitrifying bacteria that are abundant on the surface layer of the microbial film body convert ammonia nitrogen (NH4-N) into nitrate nitrogen (NO X N), and bacteria such as Bacillus in the inner layer of the microbial film body under anaerobic conditions consume the oxygen in the nitrate nitrogen and decompose the organic matter. As a result, the nitrogen component in the nitrate nitrogen is released into the air as nitrogen gas (N2) and disappears from the liquid (ammonia removal step S106).

[0026] In this way, in the ammonia removal device 80 and the ammonia removal method according to the present invention, nitrification and denitrification are almost simultaneously performed within the net-like fiber disk 52 of one ammonia removal tank 50. Therefore, as shown by the white circles in FIG. 4 described later, the amount of nitrate nitrogen in the liquid hardly changes. In addition, since nitrification and denitrification can be performed in one tank (ammonia removal tank 50), it is possible to save space and reduce construction costs compared to the conventional method using activated sludge.

[0027] Furthermore, since the organic matter necessary for denitrification exists in the microbial film body of the reticulated fiber disk 52, separate addition of organic matter becomes unnecessary. Therefore, the member cost of the organic matter to be added can be reduced. However, in the ammonia removal apparatus 80 and the ammonia removal method according to the present invention, the denitrification rate can be increased by separately adding organic matter. Even in this case, expensive methanol is not necessarily required as the organic matter to be added, and inexpensive substances such as sake lees from a sake brewery, bran and rice bran from a rice polishing factory, etc., which are mostly treated as industrial waste, can be dissolved in water and used.

[0028] Then, the treatment liquid from which ammonia nitrogen has been removed in the ammonia removal tank 50 is discharged into the sedimentation tank 22 through the water supply pipe 40b. Then, it is left standing in the sedimentation tank 22, and solids settle downward for solid-liquid separation (solid-liquid separation step S108). Also, among the treated water that has undergone solid-liquid separation in the sedimentation tank 22, the supernatant desorbed liquid is stored in the treated water tank 24. Incidentally, when the digestive juice of livestock waste is used as the waste liquid, as described above, in addition to phosphoric acid and potassium, the desorbed liquid contains organic nitrogen and can be used as a liquid fertilizer containing all the nitrogen, phosphorus, and potassium necessary for plant growth (liquid fertilizer acquisition step S110). Therefore, the liquid fertilizer stored in the treated water tank 24 is appropriately withdrawn and sprayed on the required farmland, etc.

[0029] Also, among the treated water that has undergone solid-liquid separation in the sedimentation tank 22, the sediment deposited at the bottom is appropriately withdrawn and sent to the dehydration unit 26 for dehydration (dehydration step S112). Incidentally, the water generated during dehydration contains fertilizer components necessary for plant growth, similar to the desorbed liquid of the sedimentation tank 22 stored in the treated water tank 24, so it is preferably refluxed to the storage tank 20 or the slag removal unit 28 for reuse. Also, the dehydrated sediment is sent to the compost production unit 30. Then, in the compost production unit 30, together with the impurities collected by the slag removal unit 28, predetermined measures are taken for composting (composting step S114). In this way, the obtained compost is appropriately carried out and used in the required farmland, etc.

[0030] Next, the experimental results of the ammonia removal tank 50 and the ammonia removal step S106 of the present invention will be described. First, a reticulated fiber disk 52 with a microbial film dominated by Bacillus bacteria attached thereto was prepared. Next, a simulated waste liquid in which 30 g of ammonium chloride as ammonia nitrogen was dissolved was introduced into an experimental tank (treatment tank 40) in which the reticulated fiber disk 52 was installed. The concentration of ammonia nitrogen in this simulated waste liquid was about 110 mg / L. Next, the reticulated fiber disk 52 was rotated at 1 rpm. Then, the amounts of ammonia nitrogen and nitrate nitrogen in the simulated waste liquid were measured. The measurement of the amount of ammonia nitrogen was performed using the Nessler colorimetric method, and the measurement of the amount of nitrate nitrogen was performed using the UV2 wavelength method (220 nm, 250 nm). The results are shown in the graph of Fig. 4(a). Here, the black circles in Fig. 4 indicate the amount of ammonia nitrogen, and the white circles indicate the amount of nitrate nitrogen.

[0031] From the graph of Fig. 4(a), it can be seen that the amount of ammonia nitrogen decreases with the passage of time. Also, it can be seen that the amount of nitrate nitrogen hardly changes. From this, it can be understood that ammonia nitrogen in the simulated waste liquid is nitrified and then quickly used for oxidative decomposition and released as nitrogen gas, and removed from the waste liquid.

[0032] Next, the experimental results using actual sludge treatment return water as wastewater under the same conditions as above are shown in Fig. 4(b). Also in Fig. 4(b), it can be seen that only the amount of ammonia nitrogen decreases with the passage of time as in Fig. 4(a). From this, it can be understood that the ammonia removal device 80 and the ammonia removal method according to the present invention can remove ammonia nitrogen even in actual digested liquid.

[0033] As described above, the ammonia removal apparatus 80 and ammonia removal method according to the present invention use a three-dimensionally configured polyvinylidene chloride fiber reticular fiber disc 52 as a carrier, and form a high-concentration microbial membrane dominated by Bacillus bacteria on the reticular fiber disc 52. The reticular fiber disc 52 (microbial membrane) is then rotated in the treatment tank 40, creating an aerobic state in the surface layer of the microbial membrane, converting ammonia nitrogen to nitrate nitrogen for nitrification. The inner layer of the microbial membrane is then anaerobic, and denitrification occurs, releasing the nitrogen component of nitrate nitrogen as nitrogen gas as a result of oxidative decomposition of organic matter by the dominant Bacillus bacteria. This allows for the removal of harmful ammonia nitrogen from the wastewater. Furthermore, particularly in the case of wastewater that is a digestive liquor after methane fermentation, the supernatant liquid after solid-liquid separation can be used as liquid fertilizer, and the solids can be dehydrated and used as compost for agricultural use. This allows for the construction of a recycling-oriented livestock farming system that minimizes carbon dioxide emissions.

[0034] Furthermore, the ammonia removal apparatus 80 and ammonia removal method according to the present invention can perform nitrification and denitrification almost simultaneously in one tank by using the reticulated fiber disks 52 as a carrier, as described above. This eliminates the need for multiple tanks for nitrification and denitrification, allowing for a compact system. This saves space and reduces construction costs.

[0035] Furthermore, the ammonia removal device 80 and ammonia removal method according to the present invention create an aerobic state inside the treatment tank 40 by rotating the reticulated fiber disks 52. This eliminates the need for aeration using a power-hungry blower, saving energy and reducing operating costs (electricity costs). This effectively saves commercial electricity and reduces carbon dioxide emissions even when methane gas power generation is performed.

[0036] Furthermore, there is no need to add organic matter such as methanol during denitrification, and if it is necessary, inexpensive organic matter such as sake lees, rice bran, and bran, which are easily available even in rural areas, can be used, thereby reducing component costs.

[0037] Furthermore, the configurations, members, operating mechanisms, piping routes, etc. of each tank of the ammonia removal device 80 shown in this example are merely examples, and the present invention can be implemented with modifications without departing from the gist of the present invention. Also, each step of the ammonia removal method according to the present invention shown in this example is merely an example. It is possible to change the order of the steps or appropriately incorporate necessary steps. Additionally, the present invention can be implemented with modifications without departing from the gist of the present invention.

Explanation of Reference Numerals

[0038] 20 Storage tank 22 Sedimentation tank 24 Treated water tank 26 Dewatering section 28 Slag removal section 30 Compost generation section 50 Ammonia removal tank 52 Net-like fiber disk 54 Holding section 56 Rotating section 80 Ammonia removal device S102 Seeding step S103 Collection step S104 Dominance optimization step S106 Ammonia removal step S108 Solid-liquid separation step S110 Liquid fertilizer acquisition step S112 Dewatering step S114 Composting step

Claims

1. A storage tank for storing wastewater containing ammonia nitrogen, An ammonia removal tank for decomposing ammonia nitrogen in the wastewater and discharging it as nitrogen gas, A sedimentation tank for solid-liquid separation of the treated water after ammonia nitrogen removal, and comprising: The ammonia removal tank, A reticulated fiber disk formed by shaping fibers of polyvinylidene chloride into a reticulated and disk-shaped form, A holding part for holding a plurality of the reticulated fiber disks coaxially arranged such that the lower part is immersed in the wastewater in the tank, A rotating part for rotating the reticulated fiber disk together with the holding part, and an ammonia removal device characterized by having the same.

2. The ammonia removal device according to claim 1, further comprising a treatment water tank for obtaining the separated liquid which is the supernatant of the sedimentation tank and storing it as liquid fertilizer.

3. A dehydration part for dehydrating the sediment deposited in the sedimentation tank, A slag removal part for collecting impurities in the wastewater before the ammonia removal tank, The ammonia removal device according to claim 1, further comprising a compost production part for composting the dehydrated sediment dehydrated by the dehydration part and the impurities collected by the slag removal part.

4. A seeding step of seeding Bacillus bacteria on a reticulated fiber disk formed by shaping fibers of polyvinylidene chloride into a reticulated and disk-shaped form, A dominance optimization step of growing and optimizing the Bacillus bacteria on the reticulated fiber disk, By rotating while holding the lower part of the reticulated fiber disk immersed in the wastewater containing ammonia nitrogen in the tank, the nitrifying bacteria on the surface layer of the microbial film attached to the reticulated fiber disk under aerobic conditions convert ammonia nitrogen in the waste liquid into nitrate nitrogen, and the Bacillus bacteria in the inner layer of the microbial film under anaerobic conditions consume oxygen in the nitrate nitrogen and decompose and release it as nitrogen gas. An ammonia removal method characterized by having an ammonia removal step.

5. A solid-liquid separation step of solid-liquid separating the treated water after ammonia nitrogen removal by a sedimentation method, A liquid fertilizer obtaining step of using the separated liquid which is the supernatant of the solid-liquid separation as liquid fertilizer, and the ammonia removal method according to claim 4, further comprising the same.

6. A collection step of collecting impurities in the wastewater before the ammonia removal step, A dehydration step of dehydrating the sediment separated by solid-liquid separation, The ammonia removal method according to claim 5, further comprising a composting step of composting the dehydrated sediment dehydrated by the dehydration step and the impurities collected by the collection step.

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