JP2002370097A - Nitrate nitrogen treatment apparatus and treatment method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nitrate nitrogen treatment apparatus capable of simply removing nitrate nitrogen in a large-sized water tank or a closed system such a lakes and marshes or the like at a low cost. SOLUTION: The nitrate nitrogen treatment apparatus, which is constituted so that a water stream generation member like an air bubble generator is provided and a nitrate nitrogen removing material bed comprising a sulfur/ calcium carbonate component is arranged on the way of a water stream route formed from the water stream generation member and, if necessary, a dissolved oxygen lowering member comprising a water permeable material is arranged in the periphery thereof, is sunk in a system wherein water to be treated is housed in a water tank or the like to perform denitrification.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing nitrate nitrogen in closed water bodies in a fish tank or the like.

[0002]

2. Description of the Related Art In recent years, nitrate nitrogen treatment in a closed water area has become a problem. For example, in the case of fish and shellfish breeding in an aquarium, nitrate nitrogen treatment is a common problem from small-scale hobby breeding to large-scale breeding such as land farming. Also, in the natural world, for example, in the case of closed bays and lakes where water replacement is poor, the concentration of nitrate nitrogen is increasing year by year, and this is exerting a considerable adverse effect on the marine environment.

However, in the conventional nitrate nitrogen treatment technology,
When targeting such closed waters, large-scale equipment and enormous cost are required because the original denitrification efficiency is low, such as the need to input a hydrogen donor and the need to have a water circulation device. And the measures for nitrate nitrogen treatment under such closed water conditions were insufficient.

In terms of nitrate nitrogen treatment, WO 00/186
No. 94 proposes an inexpensive and efficient nitrate nitrogen treatment by a sulfur-oxidizing bacterium using a nitrogen-removing material composed of sulfur and a calcium-based component. Since this method performs denitrification by the action of microorganisms, its applicability to nitrate nitrogen treatment in closed water bodies with different environments was questionable.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been developed in view of such circumstances, and solves the above-mentioned problems by using a necessary and minimum nitrogen-removing material comprising sulfur and calcium. Another object of the present invention is to provide an inexpensive and practical method for treating nitrate nitrogen in closed water bodies that enables effective removal of nitrate nitrogen in closed water bodies.

[0006]

According to the present invention, there is provided a closed system for water to be treated in a water tank, comprising a water flow generating member, wherein a sulfur and calcium carbonate system is provided in the water flow path formed by the water flow generating member. This is a nitrate nitrogen treatment apparatus provided with a nitrate nitrogen removal material layer composed of components. Also, the present invention
An apparatus for treating nitrate nitrogen, wherein a dissolved oxygen reducing member made of a water-permeable material is arranged around the nitrate nitrogen removal material layer. Further, the present invention is an apparatus for treating nitrate nitrogen, comprising a filtration member provided upstream of the nitrate nitrogen removal material layer. Here, it is advantageous that the dissolved oxygen reducing member is a porous material made of coral sand or rock wool.

Further, in the present invention, in a closed system such as water to be treated in a water tank, a circulating water flow is formed by a water flow generating member so that water in the water tank is converted into nitrate nitrogen containing sulfur and calcium carbonate-based components. This is a method for treating nitrate nitrogen that is released and circulated again into the water tank after passing through the removal material layer.
Further, the present invention relates to the method for treating nitrate nitrogen, wherein water in a large water tank or a lake is introduced into the water tank, and at least a part of the water in the water tank or the treated water is returned to the large water tank or the lake. is there.

Next, some preferred embodiments of the present invention will be described. a) a rising pipe which has a structure in which a container having at least a part of a water-permeable solid wall is immersed in a water tank or water to be treated, and which rises almost vertically from a lower portion of the container; A gas generating portion for generating a rising water flow inside the pipe, a rising pipe having a tip end of the pipe protruding from the container and reaching the water at the upper part of the container; An apparatus for treating nitrate nitrogen in a closed system water body provided with a nitrate nitrogen removal material layer composed of sulfur and calcium carbonate-based components inside. Here, the riser and the gas generating unit are examples of the water flow generating member. The water permeable solid wall is also an example of the oxygen reducing member.

B) The lower part of the container is a lower filter plate,
An apparatus for treating nitrate nitrogen, wherein a nitrate nitrogen removal material layer is provided thereon, and one or more risers are provided at arbitrary positions. Here, the permeable solid wall is gravel, coral sand,
Any of nonwoven fabric and rock wool or a mixture thereof or a porous material filled with them, or the water-permeable solid wall is a porous material having a rock wool layer, and the porous material is a water-permeable membrane, Advantageously, it is a film, wire mesh or glass. It is also advantageous to have a rock wool layer between the lower filter plate and the nitrate nitrogen removing material layer composed of sulfur and calcium components.

D) An apparatus for treating nitrate nitrogen in which a riser tube having a gas generating section for generating a rising water flow is disposed at the center of the nitrate nitrogen removal material layer. Here, a riser having a gas generating portion for generating a rising water flow is disposed at the center by bending or not bending the lower end of the riser so as to be disposed at the center of the nitrate nitrogen removing material layer. It is advantageous to provide a plurality of water-permeable holes in the central riser, or to provide two or more risers having a gas generator for generating a rising water flow.

E) a rising pipe which is immersed in a water tank or to-be-treated water at least partially comprising a water-permeable solid wall, and which rises almost vertically from a lower part of the container; A gas generator is provided inside the pipe to generate a rising water flow, and gas is introduced from the outside into the gas generator of the riser pipe, where the tip of the pipe protrudes from the container and reaches the water at the top of the container. Then, water is sucked up from the riser to form a circulating water flow in the water tank, and the water in the water tank is passed through the water-permeable solid wall, and the sulfuric acid and the nitric acid composed of the calcium carbonate-based component filled in the container are filled. A method for treating nitrate nitrogen, which is passed through a layer of nitrogen-removing material, sucked up from a riser, released into a water tank, and circulated.

The treatment apparatus of the present invention may be any one having a nitrate nitrogen removing material layer and a water flow generating member passing through the layer. In order to maintain the nitrate nitrogen removing material layer at a predetermined thickness, a container is required. It is preferable to dispose a nitrate nitrogen removing material layer on the shape. The shape of the container is arbitrary, but a rectangular parallelepiped is advantageous from the viewpoint of ease of manufacture, but may be a cylinder or the like. Further, it is not necessary to provide one of these treatment devices in the water tank, and a plurality of treatment devices may be used according to the purpose. The method of use may be, for example, a type connected in series or a type arranged in parallel. Furthermore, in the case of a parallel type, a bubble generating device may be provided for each. Also,
The cylindrical shape and the rectangular parallelepiped shape may be used together, and the arrangement may be parallel or serial. Further, it is preferable that the water flow generating member has a riser tube and a bubble generating portion that protrude into the water from the container.

The container is open at the top or at least partially formed of a water-permeable solid wall. The water in the water tank passes through the nitrate-nitrogen removing material layer at a predetermined speed. A portion composed of a water-permeable solid wall and a water-permeable material are selected. Usually, the container is used in a state of being submerged in water, and the water that has passed through the layer of the nitrate-nitrogen removing material in the container is returned to the water tank from the riser. At this time, it is also advantageous to divide the water tank into two or more tanks, and to preferentially return the water returned from the rising pipe to the water tank to another large water tank or the like.

Here, the water-permeable solid wall may be made of a net or a porous body, and has a granular or fibrous material such as gravel, coral sand, nonwoven fabric and rock wool in contact therewith. Is also good. It is preferable that at least a part of these also serve as a dissolved oxygen lowering member. Preference is given to coral sand or rock wool, because it consumes dissolved oxygen to increase the activity of denitrifying bacteria and is effective for the propagation of oxidizing bacteria which can reduce BOD. When these are granular materials and the like, the outside is a water-permeable membrane, fiber, film,
It is advantageous to wrap in wire mesh or glass. It is also advantageous to provide a lower filter plate to remove SS. Furthermore,
It is also advantageous to provide a rock wool layer between the water permeable solid wall and the nitrate nitrogen removing material layer to widen the breeding ground for denitrifying bacteria.

The nitrate nitrogen removing material comprising sulfur and calcium carbonate-based components used in the present invention is the above-mentioned WO 00
/ 18694 and the like can be used.
Preferably, sulfur and calcium carbonate powder such as limestone powder are mixed at a ratio of about 1: 2 to 2: 1, and the sulfur is melted and integrated, cooled, and pulverized to a predetermined particle size. No. The structure and amount of the nitrate-nitrogen removing material layer can be designed in accordance with the amount of treated water and the concentration of nitrogen content. Generally, the filling amount is preferably 0.05 to 2 times the amount (kg) of the inflow water (kg), and more preferably 0.1 to 1 times the amount. Other processing conditions are WO00 / 18694
The design may be made in accordance with the publication of Japanese Patent Application Laid-Open Publication No. H10-209,878. The particle shape of the nitrate nitrogen removing material is not limited, but preferably has an irregular shape of 20 mm or less. Although the denitrification effect can be exhibited even if the particle shape is 20 mm or more, sometimes the case where an effective flow of water in the treatment tank cannot be obtained may occur.
The method for filling the nitrate nitrogen removing material is not particularly limited, but it is preferable that the material is filled with a bulk specific gravity of 0.5 or more. If the bulk specific gravity is less than 0.5, effective denitrification may not be obtained because sometimes the flow of water flowing in the inorganic packed bed may cause a drift.

The water to be treated, nitrate nitrogen (NO ₂ ^- or NO ₃ ^-)
The device of the present invention is suitable for water in a closed system water area, for example, a water tank for fish farming, a pool, a pond, and the like. The nitrate nitrogen in the water to be treated can correspond to several ppm to several thousand ppm. In the present invention, the gas used for bubble generation is not particularly limited,
Normal air is fine. However, due to the use of sulfur oxidizing and denitrifying bacteria, the treatment effect may be enhanced by the generation of bubbles by nitrogen gas. Since the principle of the nitrate nitrogen treatment in the present invention is based on the nitrate nitrogen removal material and the sulfur oxidizing and denitrifying bacteria, the temperature of the treatment tank is 10 to 50 ° C.
And more preferably 20 to 40 ° C. If the temperature of the treatment tank is lower than 10 ° C. or higher than 50 ° C., it is not preferable because the activity of the sulfur oxidizing and denitrifying bacteria decreases.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus of the present invention and a processing method using the apparatus will be described below in more detail with reference to the drawings. FIG. 1 is a sectional view showing a container-like body and a riser portion of the apparatus of the present invention. The container comprises a water-permeable solid wall 1 and a lower filter plate (3). A nitrate-nitrogen removing material layer (2) is provided inside the container. An ascending pipe (4) is provided almost directly above the lower filter plate (3) of the container, and a gas blowing device (6) for generating an ascending water flow is provided at a lower portion of the ascending pipe. Have been. This device is submerged in a water tank (not shown), and the upper end of the riser (4) has a water level at which it is submerged in water.

The water in the water tank passes through the nitrate nitrogen removing material layer (2) from the solid wall 1, passes through the lower filter plate (3), rises through the riser (4), and is treated. It becomes water (5) and merges into the water tank. At that time, the nitrate nitrogen changes into harmless nitrogen gas by the action of the nitrate nitrogen removal material and the denitrifying bacteria. The filter plate (3) can be like foam glass, and a portion of the water that has passed through the nitrate nitrogen removal material layer may merge directly from the filter plate (3) into the water tank.

In the treatment of nitrate nitrogen in a closed water area,
It is necessary to flow the water to be treated into the treatment tank. Therefore, in the conventional method, ancillary equipment other than the original treatment, such as suction of the water to be treated by a pump, installation of a circulation device, and a stirrer, becomes large-scale. Therefore, in the present invention, by installing an air bubble generating device (6) inside a pipe existing at the center of the apparatus, the rising water flow in the pipe due to the generation of air bubbles causes the sulfur and calcium-based The water to be treated can be drained from the upper permeable solid wall (1) to the nitrate-nitrogen removing material layer composed of the components.

The water-permeable solid layer in FIG. 1 is not particularly limited, but is preferably any of gravel, coral sand, nonwoven fabric, rock wool or a mixture thereof, and more preferably, rock wool. is there. Since rock wool has fine voids, it is most suitable for the propagation of denitrifying bacteria and the like, so that a particularly excellent nitrate nitrogen effect can be obtained. When these cannot maintain a predetermined shape, it is preferable to form the outer shape or the outer shape and the inner shape with a porous resin, wire mesh, foam glass, or the like.

The upper structure of the riser is not limited as long as it has an opening, but it has an L-shape as shown in FIG.
The letter shape is advantageous. There is no particular limitation on the length and thickness of the riser. In the case of a water tank, the riser can be designed according to the height of the water tank, and in the case of a pond or swamp, it can be designed according to the water depth. Further, the structure and size of the lower filter plate are not particularly limited, and a commercially available lower filter device can be used. There is no particular limitation on the installation position or the number of risers installed vertically to the lower filter plate.

FIG. 4 is a sectional view showing another embodiment of the present invention, in which an example in which a rock wool layer (7) is present between a lower filter plate (3) and a nitrate nitrogen removing material layer (2). Show. With such a structure, it is possible to obtain a more excellent effect on the nitrate nitrogen treatment. The other symbols in the figure are the same as those in FIG.

FIG. 5 is a cross-sectional view showing another embodiment of the present invention, wherein the container (10) does not have a water-permeable solid wall at the top,
The water to be treated directly enters the inside from the surface (8) of the nitrate-nitrogen removing material layer (2), contacts and is denitrified, and rises from the lower part (9) of the pipe by gas from the gas blowing device (6). And flows out as treated water (5).

FIG. 6 is a cross-sectional view showing another embodiment of the present invention. The water to be treated flows from the water-permeable solid wall (11), passes through the nitrogen-removing material-filled layer (2) inside, and becomes a plurality of pieces. After entering the hole portion of the riser pipe (12) having the hole, the gas moves from the lower part to the upper part of the pipe by the gas blowing device (6), and merges into the closed system water area as the treated water (5). The water-permeable solid wall (11) capable of obtaining more effective results also in the apparatus shown in FIG. 6 is not limited as long as it has water permeability, but is preferably rock wool. Since rock wool has an excellent effect on the presence of biological bacteria such as denitrifying bacteria, it is possible to perform more effective nitrate nitrogen treatment. Further, the role of preventing segregation of water permeation can be obtained by the fiber structure of rock wool.
Further, rock wool can be used in combination with other fibers, plastics, metals, etc. to increase strength.

FIG. 7 is a cross-sectional view showing another embodiment of the present invention. The water to be treated flows from the water-permeable solid wall (11), and the nitrogen-removing material-filled layer (2) inside, and then the rock wool layer ( 13) Passing pipe with multiple holes (12)
After entering the hole, the water is raised by the gas blowing device (6) to become treated water (5).

FIGS. 8 and 9 are sectional views showing another embodiment of the present invention. The water to be treated flows from the water-permeable solid wall (11) and passes through the nitrogen-removing material-filled layer (2) inside. After passing through the rock wool layer (13) and entering the hole portion of the riser pipe (12) having a plurality of holes, it rises by the gas blowing device (6), and is treated with the treated water (5). Become.
In the embodiment shown in FIGS. 8 and 9, the riser (12) is bent horizontally at the lower part to form a horizontal nitrogen-removing material-filled layer (2).
And has a large contact area.

FIGS. 10 and 11 are cross-sectional views showing another embodiment of the present invention. The water to be treated flows from the water-permeable solid wall (11) and passes through the nitrogen-removing material-filled layer (2) inside. After passing through the rock wool layer (13) and entering the hole portion of the riser pipe (12) having a plurality of holes, the riser pipe (6) rises by the gas blowing device (6) to form the treated water (5). Become. The embodiment shown in FIGS. 10 and 11 is an example in which there are two risers connected by a nitrogen-removing-material-filled layer (2). By providing two or more risers, the amount of circulating water can be increased and the processing capacity can be improved.

In the embodiments shown in FIGS. 4 to 11, the principle shown in FIGS. 2 and 3 can be adopted for the principle of drawing treated water into the apparatus and the upper structure of the pipe. Further, various modifications as described in the apparatus of FIG. 1 are possible. As shown in the above figures, the device of the present invention can be in various modes. For example, there are many types such as a horizontal type and a vertical type, a type having two or more risers, a type having no permeable solid wall, and a type not having a lower filter plate. There is no particular limitation on the method of treating the water to be treated using the apparatus of the present invention, but a method of treating the water in a water tank separate from the water to be treated, a method of directly disposing the water in a water tank or pond having the water to be treated, There are ways to do that.

[0029]

Embodiments of the present invention will be described below. Example 1 Two 60 cm × 30 cm × 30 cm seawater storage tanks were prepared, and 50 L of seawater was added to each tank.
Was installed. The device uses a biofilter 60 made of Nissor for the lower filter plate,
A nitrogen-removing material filling tank composed of 1 kg of molten mixed nitrogen-removing material particles comprising 50 parts by weight of irregularly shaped sulfur and 50 parts by weight of calcium carbonate having a range of 5 to 20 mm, and a lock having a thickness of 7 m made by Shin Nikka Rockwool Co. Wool sheets were used. The bubble generator is a Nisso sheeter 12.
00 was used. All seawater is circulating in a closed system. The temperature of the processing tank was set at 30 ° C. In this seawater storage tank, OK-F-2 manufactured by Otsuka Chemical Co.
g / L, and the change with time of the nitrate nitrogen concentration was examined. From this, it is possible to grasp a favorable removal state of the nitrate nitrogen body. Nitrate nitrogen (NO ₃ ) concentration change (mg /
L) is shown in Table 1.

[0030]

[Table 1]

Example 2 Three water tanks having the same shape as in Example 1 were prepared, and 50 L
, And a nitrate nitrogen treatment apparatus having the shape shown in FIGS. 5, 6 and 7 was installed. In the apparatus according to FIG. 5, a 10 cm × 10 cm × 25 cm height container made of acryl is used, and 50 parts by weight of irregular shaped sulfur and 50 parts by weight of calcium carbonate having a range of 5 to 20 mm are contained therein. A nitrogen removing material consisting of 1 kg of the mixed nitrogen removing material particles was filled, and a VU13 PVC pipe was used as a pipe. On the other hand, in the apparatus according to FIGS. 6 and 7, a 7 m-thick rock wool sheet manufactured by Shin Nikka Rock Wool Co., Ltd. is used.
A nitrogen-removing material consisting of 1 kg of molten mixed nitrogen-removing material particles consisting of 50 parts by weight of irregularly shaped sulfur and 50 parts by weight of calcium carbonate having a range of about 20 mm was filled. In addition, a sheeter 1200 manufactured by Nisso was used as the bubble generator. All seawater is circulating in a closed system. The temperature of the processing tank was set at 30 ° C. In this seawater storage tank, OK
-F-2 was charged so as to have a nitrate nitrogen concentration of 200 mg / L, and the change with time of the nitrate nitrogen concentration was examined. From this, it is possible to grasp a favorable removal state of the nitrate nitrogen body. Table 2 shows the change in the concentration of nitrate nitrogen (NO ₃ ) (mg / L).

[0032]

[Table 2]

[0033]

According to the present invention, a simple, low-cost, and efficient nitrate nitrogen treatment can be effectively applied to the problem of treating a large-scale and large-cost nitrate nitrogen in a tank or seawater. realizable. The effect of the invention is remarkable.

[Brief description of the drawings]

FIG. 1 is a sectional view of a processing apparatus of the present invention.

FIG. 2 is an explanatory view of a riser.

FIG. 3 is an explanatory view of another riser pipe.

FIG. 4 is a sectional view of another processing apparatus of the present invention.

FIG. 5 is a sectional view of another processing apparatus of the present invention.

FIG. 6 is a sectional view of another processing apparatus of the present invention.

FIG. 7 is a sectional view of another processing apparatus of the present invention.

FIG. 8 is a sectional view of another processing apparatus of the present invention.

FIG. 9 is a sectional view of another processing apparatus of the present invention.

FIG. 10 is a sectional view of another processing apparatus of the present invention.

FIG. 11 is a sectional view of another processing apparatus of the present invention.

[Explanation of symbols]

 1: Permeable solid wall 2: Nitrate nitrogen removal material layer 3: Filter plate 4: Up pipe 6: Gas blowing device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B01D 35/027 C02F 1/58 T C02F 1/58 3/28 A 3/28 B01D 35/02 CG

Claims (6)

[Claims] In a closed system such as water to be treated in a water tank,
An apparatus for treating nitrate nitrogen, comprising a water flow generation member, and a nitrate nitrogen removal material layer comprising sulfur and calcium carbonate-based components provided in the middle of a water flow path formed by the water flow generation member. 2. The apparatus for treating nitrate nitrogen according to claim 1, wherein a dissolved oxygen reducing member made of a water-permeable material is arranged around the nitrate nitrogen removal material layer. 3. An upstream side of the nitrate nitrogen removing material layer,
The apparatus for treating nitrate nitrogen according to claim 1, further comprising a filtration member. 4. The apparatus for treating nitrate nitrogen according to claim 1, wherein the dissolved oxygen reducing member is a porous material made of coral sand or rock wool. 5. In a closed system such as water to be treated in a water tank,
By forming a circulating water flow from the water flow generating member, the water in the water tank is allowed to pass through the nitrate nitrogen removing material layer composed of sulfur and calcium carbonate-based components, and then discharged again into the water tank,
A method for treating nitrate nitrogen, comprising circulating. 6. The nitrate nitrogen treatment according to claim 5, wherein water from a large water tank or a lake is introduced into the water tank, and at least a part of the water or the treated water in the water tank is returned to the large water tank or the lake. Method.