JP2012075384A - System for automatic denitrification of closed water area - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to exactly and quickly suppress increase in nitric acid concentration without changing water, when breeding fishes in a closed water area.SOLUTION: There is provided a system including denitrification circulation tank 7 taking in water in a closed water area 2 and reducing the nitric acid contained in the taken-in water to be converted into nitrogen gas, a water flooding means 13 for taking in water in the closed water area 2 into the denitrification circulation tank 7, a circulation means 16 for circulating water in the denitrification circulation tank 7, an extrusion means 20 for returning the water in the denitrification circulation tank 7 to the closed water area 2, a water level detection means 23 set in the denitrification circulation tank 7 to detect the water level in the denitrification circulation tank 7, a heater 24 set in the denitrification circulation tank 7, and an oxidation-reduction potentiometer 25 set in the denitrification circulation tank 7 to measure the oxidation-reduction potential of water in the denitrification circulation tank 7, wherein the inside of the denitrification circulation tank 7 is divided into a denitrification area 10 having a denitrification part 12 and a circulation area 11 for circulating water in the denitrification part 12 to the denitrification area again.

Description

  The present invention relates to an automatic denitrification system for closed water areas that can automatically reduce nitric acid in closed water areas such as aquaculture, sacrifice, and ornamental fish display to convert it into nitrogen gas. Part of the water in the closed water system is taken into the denitrification circulation tank. If nitric acid is present in the water taken into the denitrification circulation tank, the denitrification treatment is repeated until the nitric acid is exhausted, and after the nitric acid is exhausted. The water in the denitrification circulation tank is returned to the closed system water area, which makes it possible to keep the nitric acid concentration in the closed system water area constant at a low value without having to deal with water exchange. The present invention relates to an improved invention of the system.

  As is well known, when raising seafood in closed waters such as aquaculture, ginger, and ornamental fish display, ammonia nitrogen generated from waste products and food residues from seafood is toxic. Since it is strong, the accumulation of ammonia nitrogen is not allowed in order to prevent the killing of the fish and shellfish reared. For this reason, in these closed waters, ammonia nitrogen generated from waste products from fish and seafood and food residues is generally converted to less toxic nitrate nitrogen by treatment with aerobic bacteria called biofiltration. Has been oxidized ("nitrification").

  And, as a specific method, for example, put sand as a filtering material in the main body, adhere aerobic bacteria to this sand and configure a filtration device, by a pump, the water in the water tank, A general method is to circulate while passing through the filtration device. According to this method, toxic substances such as ammonia contained in the aquarium water are nitrified by aerobic bacteria while the aquarium water passes through the filtration device. It can be changed to nitrate nitrogen which is weakly toxic.

  In this way, a filtration device using aerobic bacteria can nitrify toxic substances such as ammonia contained in aquarium water to less toxic nitrate nitrogen, but this nitrate nitrogen also accumulates excessively. If the concentration is increased, an adverse effect occurs. Therefore, a certain allowable range is set for the concentration.

  On the other hand, since nitric acid is the final substance of nitrification and accumulates in closed water bodies, it was previously said that when the concentration of nitrate nitrogen exceeded the allowable range, water had to be replaced. In the case of aquaculture, sacrifice, large-sized ornamental fish display, etc., it has been pointed out that the labor, time, cost, etc. required for water exchange work are large.

  Therefore, in the past, the present inventor has proposed an automatic denitrification system capable of completely suppressing an increase in the concentration of nitric acid in a closed water area without changing water when raising seafood in the closed water area. .

  That is, in this conventional automatic denitrification system, the denitrification circulation tank for taking in the water in the closed water system and the nitric acid contained in the water taken into the denitrification circulation tank are reduced and converted to nitrogen gas. And a dewatering tower for taking water in the closed water area into the denitrification circulation tank, and a circulation means for circulating the water in the denitrification circulation tank through the denitrification tower And an extruding means for returning the water in the denitrification circulation tank to the closed system water area, taking a part of the water in the closed system water area into the denitrification circulation tank, and the water taken into this denitrification circulation tank Circulates between the denitrification tower and the denitrification circulation tank, reducing the nitric acid contained in the water taken into the denitrification circulation tank to convert it into nitrogen gas. After running out of water, the water in the denitrification circulation tank that does not contain nitric acid is returned to the closed water area. This makes it possible to keep the nitric acid concentration in the closed water area constant at a low value without having to deal with water changes when raising seafood in closed water areas such as aquaculture, sacrifice, and ornamental fish displays. did.

JP 2010-88307 A JP 2003-103294 A JP 9-38683 A JP-A-9-155380 JP 2002-159244 A Special Table 2000-513224 Japanese Patent Laid-Open No. 03-049630 Japanese Patent Publication No. 07-055116 Japanese Patent No. 3769680

  However, in the above-described conventional automatic denitrification system, the denitrification circulation tank for taking in the water in the closed water area and the nitric acid contained in the water taken into the denitrification circulation tank are reduced to nitrogen gas. A denitrification tower for conversion is provided separately and independently, and the denitrification circulation tank and the denitrification tower are communicated by the circulation means, and the water taken into the denitrification circulation tank through the circulation pump in the path of the circulation means Is circulated between the denitrification tower and the denitrification circulation tank, because the water in the denitrification circulation tank has been pressed into the denitrification tower by the circulation pump, There was a problem in that the air was entrained and the circulation stopped.

  In addition, in a denitrification tower in a conventional automatic denitrification system, a bacteria implantation part for implanting denitrification bacteria as anaerobic bacteria in a cylindrical container (“column”), and nutrients of the denitrification bacteria In this configuration, when anaerobic bacteria increase in the denitrification tower, slime is generated, which causes the bacteria implantation part In such a case, there has been a problem that the press-fitting of the water in the denitrification circulation tank into the denitrification tower by driving the circulation pump does not proceed smoothly. .

  Furthermore, in the aforementioned automatic denitrification system, a nitrate ion meter was used as a nitric acid concentration detection means for detecting the nitric acid concentration contained in the water taken into the denitrification circulation tank. In the case of seawater, the nitrate ion meter cannot detect the nitric acid concentration accurately and quickly.

  Therefore, the present invention takes the water in the closed system water area into the denitrification circulation tank, reduces the nitric acid contained in the water taken into the denitrification circulation tank to convert it into nitrogen gas, and the denitrification is completed. When water is returned to a closed system, and when seafood is bred in a closed system such as aquaculture, sacrifice, and ornamental fish display, the concentration of nitric acid in the closed system is reduced without any need for water exchange. In an automatic denitrification system in a closed water area that makes it possible to keep it constant, the concentration of nitric acid in the denitrification circulation tank can be detected accurately and quickly, and the denitrification of water taken into the denitrification circulation tank can be performed. It is an object to provide an automatic denitrification system for closed water areas that can be reliably performed.

The automatic denitrification system for closed water areas of the present invention is
An automatic denitrification system for closed water areas,
A denitrification circulation tank for taking in water in a closed water body and reducing nitric acid contained in the taken-in water to convert it into nitrogen gas;
Water filling means for taking water in a closed system water area into the denitrification circulation tank;
A circulation means for circulating the water in the denitrification circulation tank;
Extrusion means for returning the water in the denitrification circulation tank to the closed water area;
A water level detecting means for detecting a water level in the denitrification circulation tank, disposed in the denitrification circulation tank;
A heater disposed in the denitrification circulation tank;
An oxidation-reduction potentiometer for measuring the oxidation-reduction potential of water in the denitrification circulation tank, disposed in the denitrification circulation tank;
Control means for controlling the operation of the entire system,
The denitrification circulation tank is
The inside of the denitrification area for taking in the water in the closed system water area by the partition plate and reducing nitric acid contained in the taken water to convert it into nitrogen gas, and the water that has passed through the denitrification area Divide it into a circulation area to circulate again to the denitrification area,
The denitrification area has a bacteria implantation part for implanting anaerobic bacteria and a biodegradable polymer as a nutrient for the anaerobic bacteria, and allows water containing nitric acid to pass through. , Comprising a denitrification part that can convert nitric acid contained in water to nitrogen gas,
In the lower part, the partition plate has a communication part in which the denitrification area and the circulation area communicate with each other, and water that has passed through the denitrification part can be moved to the circulation area,
Taking in water from a closed water area into the denitrification area of the denitrification circulation tank by the water filling means,
By circulating the water taken into the denitrification area by the circulation means between the circulation area and the denitrification area while passing through the denitrification part, the nitric acid contained in the water taken into the denitrification area is removed. Reduced to nitrogen gas,
It is possible to return the water in the denitrification circulation tank not containing nitric acid to the closed water body by the extrusion means.

  When anaerobic bacteria (“denitrifying bacteria”) respirate nitrate under anaerobic conditions, nitrate is reduced and converted to nitrogen gas (this is called “denitrification”), but the closure of the present invention. In the automatic denitrification system of the system water area, it has a denitrification circulation tank for taking in the water in the closed system water area and reducing nitric acid contained in the taken water to convert it into nitrogen gas, and in the closed system water area Water filling means for taking the water in the denitrification circulation tank, circulation means for circulating the water in the denitrification circulation tank, and extrusion means for returning the water in the denitrification circulation tank to the closed system water area The denitrification circulation tank has a denitrification area for taking in the water in the closed system water area by the partition plate and reducing nitric acid contained in the taken water to convert it into nitrogen gas. Then, the water that has passed through the denitrification area is recycled to the denitrification area again. The denitrification area is divided into a circulation area, a bacteria implantation part for implanting anaerobic bacteria, and a biodegradable polymer as a nutrient for the anaerobic bacteria, and nitric acid. A denitrification unit is provided that allows the nitric acid contained in the water to be reduced and converted to nitrogen gas by passing the contained water, and the partition plate communicates with the denitrification area and the circulation area in the lower part. A water filling step that allows the water that has passed through the denitrification section to move to the circulation area, and in this configuration, incorporates a part of the water in the closed water area into the denitrification area of the denitrification circulation tank; In the denitrification area, the nitric acid contained in the water taken into the denitrification area is reduced until the nitric acid contained in the water taken into the denitrification area is reduced and converted to nitrogen gas, and contained in the water in the denitrification area Denitrification when the nitric acid that had been used is gone It is set to be performed an extrusion step of returning the water in the ring chamber in a closed system waters.

  Therefore, according to the present invention, when raising seafood in closed water areas such as aquaculture, ginger, ornamental fish display, etc., the increase in nitric acid concentration is completely suppressed, and the closed water area does not respond by changing water. It is possible to keep the nitric acid concentration in the inside constant at a low value.

  And at this time, in this invention, the inside of a denitrification circulation tank is divided | segmented into a denitrification area and a circulation area by a partition plate, and the denitrification area is contained in water by allowing the water containing nitric acid to pass through. It is equipped with a denitrification unit that can convert nitric acid into nitrogen gas by reducing it, and in this way, in the denitrification circulation tank, it takes in water in the closed water area and reduces nitric acid contained in the taken-in water Therefore, a denitrification circulation tank for taking in the water in the closed system water area and a denitrification tower for reducing nitric acid contained in the water taken into the denitrification circulation tank are provided separately, A conventional automatic denitrification system in which a denitrification tower is connected by a circulation means and a circulation pump is interposed in the circulation means, and water in the denitrification circulation tank is pressed into the denitrification tower by this circulation pump. Unlike that, the circulation stops Theft can be prevented.

  Further, in the automatic denitrification system of the present invention, a denitrification part having a bacteria implantation part for implanting anaerobic bacteria and a biodegradable polymer as a nutrient for anaerobic bacteria in the denitrification area. Unlike conventional automatic denitrification systems in which a denitrification tower is configured by alternately packing bacteria in the column and biodegradable polymer in a sandwich shape in the column, even when anaerobic bacteria increase, There is no hindrance to the taken-in water passing through the denitrification section, and denitrifying bacteria can be reliably propagated.

  Furthermore, in the automatic denitrification system of the present invention, an oxidation-reduction potentiometer for measuring the oxidation-reduction potential of water in the denitrification circulation tank is disposed in the denitrification circulation tank. Based on the measurement results, the presence or absence of nitric acid contained in the water taken into the denitrification circulation tank is judged, so the concentration of nitric acid contained in the water taken into the denitrification circulation tank using a nitrate ion meter is determined. Unlike the conventional automatic denitrification system that has been detected, the concentration of nitric acid can be detected accurately and quickly even when the water in the closed system is seawater.

  Moreover, in the automatic denitrification system for closed system water areas of the present invention, a water filling process for moving a part of the water in the closed system water area to the denitrification circulation tank, and a circulation process for circulating the water in the denitrification circulation tank; In the circulation process, oxygen is not introduced from the outside into the denitrification circulation tank, and dissolved oxygen is immediately depleted by anaerobic bacterial oxygen respiration. Therefore, it is possible to quickly increase the denitrification activity of anaerobic bacteria in the denitrification circulation tank.

It is a figure for demonstrating the whole system of the Example of the automatic denitrification system of the closed water area of this invention. It is a figure for demonstrating the control system of the Example of the automatic denitrification system of the closed water area of this invention. It is a flowchart for demonstrating the effect | action of the Example of the automatic denitrification system of the closed water area of this invention. It is the waveform which showed a mode that ORP decreased by denitrification.

  In the automatic denitrification system for closed water areas of the present invention, water in closed water areas such as aquaculture, sacrifice, and ornamental fish display is taken in, and nitric acid contained in the taken water is reduced and converted to nitrogen gas. A denitrification circulation tank, a water filling means for taking water in the closed water area into the denitrification circulation tank, a circulation means for circulating the water in the denitrification circulation tank, and a denitrification circulation tank And an extrusion means for returning the water to the closed water area.

  Further, in the denitrification circulation tank, a water level detection means for detecting the water level in the denitrification circulation tank and a heater for maintaining the water temperature in the denitrification circulation tank above a certain level are arranged. Further, an oxidation-reduction potentiometer for measuring the oxidation-reduction potential of water in the denitrification circulation tank is disposed in the denitrification circulation tank, and these water level detection means, heater, and oxidation-reduction The electrometer is connected to control means for controlling the operation of the entire system.

  The inside of the denitrification circulation tank is divided into a denitrification area and a circulation area by a partition plate. The denitrification area takes in water in the closed water area and reduces nitric acid contained in the taken-in water. In this area, there is a denitrification section that has a bacteria implantation section for implanting anaerobic bacteria and a biodegradable polymer as a nutrient for anaerobic bacteria. Thus, the denitrification section allows the water taken from the closed water area to pass through, thereby reducing nitric acid contained in the water and converting it into nitrogen gas.

  On the other hand, the circulation area is an area for circulating the water that has passed through the denitrification unit again to the denitrification area and passing through the denitrification unit.

  In addition, the partition plate has a communication portion in the lower portion where the denitrification area and the circulation area communicate with each other, and water that has passed through the denitrification portion passes through the communication portion to the circulation area. It can be moved.

  And the automatic denitrification system of the closed system water area of the present invention, in such a configuration, the water of the closed system water area is taken into the denitrification area of the denitrification circulation tank by the water filling means, and after the water filling, The water taken into the denitrification area is converted to nitrogen gas by passing through the denitrification section to reduce the nitric acid contained in the water, and the water taken into the denitrification area is free of nitric acid. Until it is determined that the water passed through the denitrification section is circulated between the circulation area and the denitrification area by the circulation means, and when it is determined that the water in the denitrification area is no longer containing nitric acid, the extrusion means Therefore, the water in the denitrification circulation tank is returned to the closed water area.

  Here, the operation of the water filling means, the circulation means, and the extrusion means is automatically controlled by the control means, whereby the water filling step, the circulation step, and the extrusion step may be automatically executed, thereby minimizing the minimum amount. Each process can be performed with effort.

  As an example of automatic control, for example, when the water level detection means detects a decrease in the water level in the denitrification circulation tank, a method of taking water in the closed water area into the denitrification circulation tank by the water filling means can be considered. According to this, water filling can be performed automatically.

  In addition, as an example of automatic control, it is determined that nitric acid is present in the water in the denitrification circulation tank based on the oxidation-reduction potential value of the water in the denitrification circulation tank by the oxidation-reduction potentiometer. If the water in the denitrification circulation tank is determined to be no longer present in the water in the denitrification circulation tank, the water in the denitrification area is passed between the circulation area and the denitrification area while passing through the denitrification section by the circulation means. When it is judged that nitric acid is not present in the water in the denitrification circulation tank, a method of returning the water in the denitrification circulation tank to the closed system water area by an extrusion means can be considered, Based on the measurement result obtained by the oxidation-reduction potentiometer, the circulation process and the extrusion process can be automatically executed.

  The circulation means includes a submersible pump disposed in the circulation area, a base end portion connected to the submersible pump, a tip end portion communicating with the denitrification area, and a three-way valve interposed in the middle of the path. The water filling means comprises a water filling passage whose base end communicates with the closed water area and the tip communicates with the denitrification area, and the water filling means of the closed water area through the water filling flow path. Constructed by a take-in pump for taking water into the denitrification area, the extruding means is an extruding flow path whose leading end communicates with the closed water area and whose proximal end is connected to the circulating flow path via the three-way valve. When the water in the closed system water area is taken into the denitrification circulation tank, the water in the closed system water area is taken into the denitrification circulation tank via the water filling channel and the intake pump. The three-way valve when circulating the water between the denitrification area and the circulation area. The water in the denitrification circulation tank is circulated with the denitrification area through the submersible pump and the circulation channel while allowing the circulation area and the denitrification area to communicate with each other through the circulation channel and passing through the denitrification unit. When circulating between areas and returning the water in the denitrification circulation tank to the closed system water area, the part from the base end to the three-way valve in the circulation channel and the extrusion channel are communicated by switching the three-way valve. Then, the water in the denitrification circulation tank may be pushed out to the closed system water area through the submersible pump, the part from the base end to the three-way valve in the circulation channel, and the extrusion channel. It is possible to reduce the cost by simplifying the configuration of the entire system.

  In addition, as a biodegradable polymer in the denitrification part, a polymer derived from vegetable oil may be used, and thus a highly safe denitrification system can be obtained.

  An embodiment of an automatic denitrification system (hereinafter simply referred to as “automatic denitrification system”) according to the present invention will be described with reference to the drawings. FIG. 1 illustrates the entire automatic denitrification system of this embodiment. 1 indicated by a dotted line in the figure is a main part of the automatic denitrification system of the present embodiment.

  In FIG. 1, reference numeral 2 denotes a water tank as a closed system water area, and the automatic denitrification system of this embodiment is intended to automatically denitrify nitric acid contained in the water in the water tank 2.

  Further, in the figure, reference numeral 3 denotes a filtration device, and this filtration device 3 has a landing portion such as dredged sand to which aerobic bacteria are adhered, and the water in the water tank 2 is filtered. 3 circulates through the aerobic bacteria adhering to the landing area, and the ammonia nitrogen generated in the aquarium 2 that originates from waste products from seafood and food residues is present in the weakly toxic nitric acid It is supposed to be oxidized to nitrogen.

  That is, the filtration device 3 communicates with the water tank 2 by a circulation path 4, and the circulation path 4 has a first circulation path 401 having a base end portion communicating with the water tank 2 and a distal end portion communicating with the filtration device 3. And a second circulation path 402 having a base end communicated with the filtration device 3 and a distal end communicated with the water tank 2, and a filtration pump 5 is interposed in the path of the second circulation path 402.

  Then, when the filtration pump 5 is driven, the water in the water tank 2 is circulated through the first circulation path 401, the filtration device 3, and the second circulation path 402, and the automatic denitrification system of the present embodiment. Assumes a water tank equipped with such a filtering device 3.

  In addition, since the filtration apparatus using aerobic bacteria is conventionally well-known, detailed description is abbreviate | omitted. As is well known, in FIG. 1, reference numeral 601 denotes aeration, and reference numeral 602 denotes an aeration stone for generating aeration.

  Next, in the figure, 7 is a denitrification circulation tank. That is, the automatic denitrification system of the present embodiment has a denitrification circulation tank 7 having a shape capable of storing water therein, and the water in the water tank 2 is contained in the denitrification circulation tank 7. Part of it is taken in and nitric acid contained in the taken-in water is reduced and converted to nitrogen gas.

  Here, the denitrification circulation tank 7 will be described. In the present embodiment, the denitrification circulation tank 7 has a partition plate 8 disposed therein, and the partition plate 8 allows the denitrification circulation tank 7 to be disposed therein. The interior is divided into a denitrification area and a circulation area.

  That is, in the figure, 10 is a denitrification area, and this denitrification area 10 is an area for taking in water in a closed system water area and reducing nitric acid contained in the taken water to convert it into nitrogen gas. And a denitrification section for denitrifying water taken into the denitrification area 10 is provided at the bottom.

  That is, 12 is a denitrification part in the figure, and in the present embodiment, the denitrification part 12 includes a bacteria implantation part 1201 for implanting anaerobic bacteria, and a biodegradable polymer 1202 as a nutrient of the anaerobic bacteria. When the water taken into the denitrification area 10 passes, nitric acid contained in the water that has passed through the denitrification unit 12 is reduced and converted to nitrogen gas.

  That is, under anaerobic conditions, denitrifying bacteria, which are anaerobic bacteria, respire nitrate, thereby denitrifying the action of reducing nitric acid to nitrogen gas. In the automatic denitrification system of this embodiment, A denitrification unit 12 having a bacteria implantation part 1201 for implanting denitrification bacteria, which are anaerobic bacteria, is arranged at the bottom of the denitrification area 10, and water taken into the denitrification area 10 By passing through the denitrification unit 12, the nitric acid contained in the water taken into the denitrification circulation tank 5 is reduced and converted to nitrogen gas by denitrifying bacteria.

  In this example, as the bacterial implantation part 1201, cinnabar sand capable of efficiently depositing denitrifying bacteria is used, and the biodegradable polymer and 1202 are derived from vegetable oil. Using this polymer, safety is ensured. That is, in this example, since a natural raw material is used as a biodegradable polymer, a chemical substance that should be a concern is not trapped in the cultured fish, which is a food material, and the danger to humans is extremely low. There is also an advantage that the impact on the environment is extremely low when the water of the closed water system flows out of the closed system.

  Furthermore, in this example, as the vegetable oil-derived biodegradable polymer, the trade name Matterby KF-01U / 130 manufactured by Novamont, Italy is used, thereby preventing the generation of hydrogen sulfide.

  That is, for example, when seawater is subjected to anaerobic conditions, sulfuric acid is reduced by the anaerobic bacterium, sulfate-reducing bacteria, so that highly toxic hydrogen sulfide may be generated. It may be killed. However, as a result of experiments by the inventor, no hydrogen sulfide was generated when the above-mentioned Matterby KF-01U / 130 was used as a biodegradable polymer. Therefore, in the automatic denitrification system of this embodiment using the Matterby KF-01U / 130 as a biodegradable polymer, even when seawater is circulated, no toxic hydrogen sulfide is generated.

  In the figure, 25 is an oxidation-reduction potentiometer for measuring the oxidation-reduction potential of the water taken into the denitrification circulation tank 7, and 2501 is an electrode part of the oxidation-reduction potentiometer. In the nitrogen system, as will be described later, the oxidation-reduction potential meter 25 measures the oxidation-reduction potential in the denitrification circulation tank 7, and based on the measurement result, the presence or absence of nitric acid in the water in the denitrification circulation tank 7 Is going to judge.

  Next, the circulation area 11 will be described. In the figure, 11 is a circulation area. That is, in this embodiment, the inside of the denitrification circulation tank 7 is divided into left and right by the partition plate 8, and the circulation area 11 is formed in an arrangement adjacent to the denitrification area 10.

  The denitrification area 10 and the circulation area 11 adjacent to the denitrification area 10 communicate with each other by a communication portion 9 formed at the lower end portion of the partition plate 8, thereby passing the denitrification portion 12 in the denitrification area 10. Water can be moved to the circulation area.

  In the figure, reference numeral 23 denotes a water level detecting means for detecting the water level of the water taken into the denitrification circulation tank 7, and a float switch is used as the water level detecting means 7 in this embodiment.

  In the figure, reference numeral 24 denotes a heater, and the heater 24 maintains the temperature of water in the denitrification circulation tank 7 at a certain level or more. That is, when the water temperature falls below 25 ° C., the activity of the denitrifying bacteria is extremely lowered and the speed of denitrification is slowed. Therefore, in this embodiment, the heater 24 is placed in the denitrification circulation tank 7 as a countermeasure for the water temperature in winter. The water temperature in the denitrification circulation tank 7 can be kept at 25 ° C. or higher.

  Next, in the figure, reference numeral 13 denotes water filling means for taking the water in the water tank 2 into the denitrification circulation tank 7 and filling the denitrification circulation tank 7, and in this embodiment, the water filling means 13 is: A water filling passage 14 having a proximal end communicating with the second circulation path 402 and a tip communicating with the denitrification circulation tank 7, and a two-way valve 15 interposed in the middle of the path of the water filling passage 14. It consists of.

  In this configuration, the filtration pump 5 is driven to open the two-way valve 15 in a state where the water in the water tank 2 is circulated through the filtration device 3, so that the water tank 2 passes through the filtration device 3. A part of the water that returns to is taken into the denitrification circulation tank 7.

  However, it is not always necessary to configure the water filling means also using the circulation path 4. The base end of the water filling flow path 14 is communicated with the water tank 2, and the intake pump is interposed in the path of the water filling flow path 14. The water in the water tank 2 may be directly taken into the denitrification circulation tank 7 by driving the pump.

  Next, in the figure, 16 is a circulation means. That is, in the present embodiment, the water that has passed through the denitrification unit 12 in the denitrification area 10 is moved to the circulation area by the circulation means 16 and the water that has been moved into the circulation area 11 is again removed. It is going to circulate to.

  That is, in this embodiment, the circulation means 16 connects the submersible pump 17 disposed inside the circulation area 11 and the base end portion to the submersible pump 17 and communicates the tip end portion with the denitrification area 10. The circulation channel 18 is provided.

  With this configuration, when the submersible pump 17 is driven, the submersible pump 17 sucks the water in the circulation area 11 and returns the sucked water to the denitrification area 10 via the circulation channel 18. This makes it possible to circulate the water in the denitrification circulation tank 7.

  Then, along with this, as the water in the circulation area 11 decreases, the water in the denitrification area 10 passes through the denitrification section 12 and is formed at the lower end portion of the partition plate 8 as indicated by the arrow. It moves to the circulation area 11 through the part 9.

  Therefore, it is possible to eliminate nitric acid contained in the water taken into the denitrification circulation tank 7 by repeating this circulation.

  Therefore, according to the present embodiment, the water in the denitrification area 10 is circulated between the denitrification area 10 and the circulation area 11 while passing through the denitrification section 12 only by driving the submersible pump 17. Since the water in the denitrification circulation tank 7 can be denitrified, it is possible to completely suppress the increase in the nitric acid concentration in the water tank and keep the nitric acid concentration constant at a low value without dealing with water exchange. is there.

  Next, in the figure, 20 is an extrusion means for returning the water in the denitrification circulation tank 5 to the water tank 2. In this embodiment, the extrusion means 20 is a flow path for extrusion whose tip communicates with the water tank 2. The base end of the extrusion flow path 20 is connected to the circulation flow path 18 via a three-way valve 19. In other words, in the present embodiment, the circulation flow path 18 has a three-way valve 19 interposed in the path, and the three-way valve 19 is used as a boundary, and the proximal end side circulation-use circulation pump 17 is connected to the proximal end portion. When the water in the denitrification circulation tank 5 is returned to the water tank 2 when the water is returned to the water tank 2, the flow path 18a and the front end portion are separated into a flow path 18b for leading end circulation. The flow path 18a is used.

  That is, when the water in the denitrification circulation tank 5 is returned to the water tank 2, the three-way valve 19 is switched to connect the proximal-end circulation flow path 18 a and the extrusion flow path 20, and the submersible pump 17 is driven in this state. . Then, the submersible pump 17 sucks the water in the circulation area 11, and the sucked water is returned to the water tank 2 through the proximal-end circulation flow path 18 a and the extrusion flow path 20.

  However, it is not always necessary to perform extrusion using a part of the circulation channel 18, and the base end of the extrusion channel 20 communicates with the circulation area 11 or the denitrification area 10, The water in the denitrification circulation tank 7 may be returned to the water tank 2 by interposing an extrusion pump and driving the extrusion pump.

  Next, reference numeral 21 in the figure denotes a control panel containing control means. In the automatic denitrification system 1 of this embodiment, the water filling, circulation and extrusion processes are automatically performed under the control of the control means. The control means controls the operation of the entire system.

  Here, the control system of the automatic denitrification system 1 of this embodiment will be described with reference to the block diagram of FIG. 2. The automatic denitrification system 1 of this embodiment has a microcomputer as the control means 22. The float switch 23, the heater 24, the oxidation-reduction potentiometer 25, and the submersible pump 17 are connected to the control means 22.

  In this embodiment, as the two-way valve 15 and the three-way valve 19, an electric two-way valve and a three-way valve are used, and the two-way valve 15 and the three-way valve 19 are connected to the control means 22, In addition, an operation switch 26, a power source 27, and the like are connected to the control means 22.

  Then, when the float switch 23 detects that the water level in the denitrification circulation tank 7 has become equal to or less than a preset value, the control means 22 opens the two-way valve 15 to perform the water filling, and removes the water. The water pump 17 is driven to circulate until the nitric acid in the water taken into the nitrification circulation tank 7 runs out, and when it is determined that the nitric acid in the water taken into the denitrification circulation tank 7 has run out, While the pump 17 is continuously driven, the three-way valve 19 is switched so that the extrusion flow path 20 and the proximal-side circulation flow path 18a communicate with each other, and in the winter, the heater 24 is operated to denitrify and circulate. The water temperature in the tank 7 is to be maintained at 25 ° C. or higher.

  Next, a method for automatically denitrifying water in the water tank 2 using the automatic denitrification system 1 of the present embodiment configured as described above will be described with reference to the flowchart of FIG. In the automatic denitrification method, first, the denitrification circulation tank 7 is filled with water. That is, in step 1, the control means 22 keeps the second circulation path 402 and the denitrification circulation tank 7 in communication through the water filling flow path 14 for a predetermined time while the filtration pump 5 is driven. By switching the two-way valve 15, a predetermined amount of water that passes through the filtration device 3 and returns to the water tank 2 is taken into the denitrification circulation tank 7 to be filled with water. Note that the amount of water to be taken in is not particularly limited, and it is preferable to set the time for controlling the two-way valve 15 in the control means 22 in advance according to the capacity of the denitrification circulation tank 7.

  Next, the control means 22 determines the presence or absence of nitric acid in the denitrification circulation tank 7 based on the measurement result of the oxidation-reduction potentiometer 25. When it is determined that nitric acid is present, the controller 22 circulates and determines that nitric acid is not present. Or when it is judged that nitric acid has been exhausted by the circulation, extrusion is performed.

  That is, when the control means 22 determines that nitric acid is present in the denitrification circulation tank 7, in step 2, the proximal-side circulation channel 18 a and the distal-side circulation channel are determined until it is determined that nitric acid is not present. The three-way valve 19 is switched so that 18 b communicates and the submersible pump 17 is driven to circulate the water in the denitrification area 10 between the denitrification area 10 and the circulation area 11 while passing through the denitrification section 12. Then, the water in the denitrification circulation tank 7 is denitrified.

  When the water taken into the denitrification circulation tank 7 has no nitric acid or no nitric acid has been removed by the circulation, the control means 22 communicates with the proximal-side circulation flow path 18a and the extrusion flow path 20. Thus, the three-way valve 19 is switched and the submersible pump 17 is driven to return the water in the circulation area 11 to the water tank 2 (extrusion in step 3).

  When the water level in the denitrification circulation tank 7 is reduced to a predetermined value set in advance by the extrusion in step 3, the above steps 1 to 3 are repeated, thereby automatically denitrifying the water in the water tank 2. Go on.

  Here, a method for determining the presence or absence of nitric acid based on the redox potential (“ORP”) of water taken into the denitrification circulation tank 7 will be described. Although a method using an oxidation-reduction potential has been proposed, particularly in this embodiment, the ORP of water in the water tank 2 taken into the denitrification circulation tank 7 is denitrified in the denitrification circulation tank 7, Focusing on the decrease through three stages, the presence or absence of nitric acid is determined according to this stage.

  That is, since the water immediately after being taken into the denitrification circulation tank 7 contains dissolved oxygen (“DO”) and nitric acid, the ORP is approximately +100 or more. When denitrification is started by nitrifying bacteria, DO is consumed by the denitrifying bacteria in the denitrification circulation tank 7 and the DO decreases, and the ORP starts to decrease accordingly, until the DO becomes zero. descend. This is the first stage, and the ORP when DO is completely consumed is approximately +50.

  Next, since the DO in the water is depleted at the end of the first stage, the denitrifying bacteria take respiration by depriving oxygen from the nitric acid, thereby starting to decrease the nitric acid. Along with this, the ORP gradually decreases until the nitric acid is completely consumed. This is the second stage, and the ORP when the nitric acid is completely consumed is approximately 0 or less.

  After the nitric acid is completely consumed, the ORP starts to decrease rapidly again, stops decreasing at about minus 450, and thereafter, the reduction of sulfuric acid starts, thereby generating highly toxic hydrogen sulfide. . FIG. 4 shows a waveform showing the decrease in the ORP. In the figure, the point A is the first stage end point, the DO is almost exhausted at the point A, and the portion B is consumed with nitric acid. In the second stage, the point C is an approximate point where the second stage ends and the third stage starts.

  Therefore, in the automatic denitrification system of this embodiment, the ORP of the water in the water tank 2 taken into the denitrification circulation tank 7 is reduced through three stages by denitrification in the denitrification circulation tank 7 in this way. Focusing on the process, the ORP when it is assumed that the nitric acid is completely consumed is taken as one guideline, and when the measurement result by the oxidation-reduction potentiometer becomes 0 or less, the inside of the denitrification circulation tank 7 It is judged that the nitric acid contained in the water taken in is no longer present, and that time is used as a measure for the end of circulation and the start of extrusion.

  Thus, in the automatic denitrification system of the present embodiment, the redox potential meter 25 is disposed in the denitrification circulation tank 7 to measure the redox potential of water in the denitrification circulation tank 7, and the measurement result Therefore, the presence of nitric acid contained in the water taken into the denitrification circulation tank 7 is judged, so the concentration of nitric acid contained in the water taken into the denitrification circulation tank is detected using a nitrate ion meter. Unlike conventional automatic denitrification systems, the concentration of nitric acid can be detected accurately and quickly even when the water in the closed system is seawater.

  As described above, the ORP of water in the water tank 2 taken into the denitrification circulation tank 7 decreases through three stages due to denitrification in the denitrification circulation tank 7, but each stage ends. Since the ORP value at the time varies depending on the water quality, the presence or absence of nitric acid may be determined by capturing the inflection point of the waveform indicated by the ORP.

  That is, as described above, when nitric acid starts decreasing in the second stage, the ORP gradually decreases until the nitric acid is completely consumed, and after the point C after the nitric acid is completely consumed, the ORP is again reduced. It begins to decline rapidly. Therefore, it may be determined that the nitric acid has been exhausted by capturing the time when the ORP has decreased slowly and then decreased rapidly.

  As described above, according to the automatic denitrification system of the present embodiment, it is possible to denitrify water in the aquarium, so that seafood is raised in closed water areas such as aquaculture, sacrifice, and ornamental fish display. In this case, it is possible to keep the nitric acid concentration in the closed water area constant at a low value without performing water exchange.

  And at this time, in the automatic denitrification system of the present embodiment, the water filling step for moving a part of the water in the water tank to the denitrification circulation tank and the circulation step for circulating the water in the denitrification circulation tank are separated. Since batch processing is performed as a process, it is possible to quickly increase the denitrification activity of anaerobic bacteria in the denitrification circulation tank.

  That is, for example, when seawater rich in dissolved oxygen is taken into a denitrification circulation tank and water filling is performed, oxygen enters the denitrification circulation tank. At this time, in general, denitrifying bacteria are facultative anaerobic bacteria that die when exposed to even a little oxygen, so they will not die even if oxygen is present. Activity becomes weak. Therefore, for example, when water filling and circulation are performed in parallel, oxygen is successively supplied into the denitrification circulation tank, so that the activity of the denitrifying bacteria cannot be increased and effective denitrification is performed. It becomes difficult.

  However, in this example, since the water filling process and the circulation process are batch-processed as separate processes, in the circulation process, oxygen does not enter the denitrification circulation tank from the outside, and aerobic bacteria The water taken into the denitrification circulation tank 5 by water filling due to oxygen respiration is immediately depleted of dissolved oxygen and becomes anaerobic, so that the denitrification activity of anaerobic bacteria in the denitrification circulation tank can be quickly increased. Is possible.

  Furthermore, in the present embodiment, the partitioning plate divides the inside of the denitrification circulation tank into a denitrification area and a circulation area, and the nitric acid contained in the water by passing water containing nitric acid through the denitrification area. Is equipped with a denitrification unit that can convert the nitrogen gas into nitrogen gas, and the circulation area is equipped with a submersible pump. By driving the submersible pump, the water in the denitrification area passes through the denitrification unit. Circulated between the denitrification area and the circulation area, and in this way, in the denitrification circulation tank, water in the closed system water area is reduced and nitric acid contained in the taken-in water is reduced. A denitrification circulation tank for taking in water in the water area and a denitrification tower for reducing nitric acid contained in the water taken into the denitrification circulation tank are separately provided, and the denitrification circulation tank and the denitrification tower are circulated. And a circulation pump in the circulation means path. Intervening, unlike the conventional automatic denitrification system water was pressed into a de 窒塔 denitrification circulating tank by the circulation pump, the circulation can be prevented from stopping.

  Further, in the automatic denitrification system of the present embodiment, a denitrification section having a bacteria implantation section for implanting anaerobic bacteria and a biodegradable polymer as a nutrient for anaerobic bacteria in the denitrification area. Unlike conventional automatic denitrification systems in which denitrification towers are constructed by alternately packing bacteria in the column and biodegradable polymers in a sandwich shape, even when anaerobic bacteria increase In addition, there is no hindrance to the taken-in water passing through the denitrification section, and it is possible to reliably propagate the denitrification bacteria.

  Furthermore, in the automatic denitrification system of the present embodiment, an oxidation-reduction potentiometer for measuring the oxidation-reduction potential of water in the denitrification circulation tank is disposed in the denitrification circulation tank, and this oxidation-reduction potentiometer. The concentration of nitric acid contained in the water taken into the denitrification circulation tank using a nitrate ion meter is determined based on the measurement results of Unlike conventional automatic denitrification systems that have detected water, the concentration of nitric acid can be detected accurately and quickly even when the water in the closed water system is seawater.

  According to the automatic denitrification system of the present invention, it is possible to keep the nitric acid concentration in the closed water area constant at a low value without performing water exchange. Applicable in general.

DESCRIPTION OF SYMBOLS 1 Automatic denitrification system 2 Water tank 3 Filtration apparatus 4 Circulation path 401 1st circulation path 402 2nd circulation path 5 Filtration pump 601 Aeration 602 Air stone 7 Denitrification circulation tank 8 Partition plate 9 Communication part 10 Denitrification area 11 Circulation area DESCRIPTION OF SYMBOLS 12 Denitrification part 1201 Bacteria implantation part 1202 Biodegradation polymer 13 Water filling means 14 Water filling flow path 15 Two-way valve 16 Circulation means 17 Submersible pump 18 Circulation flow path 18a Base end side circulation flow path 18b Front end side circulation flow Channel 19 Three-way valve 20 Extrusion means (Extrusion channel)
21 Control plate 22 Control means 23 Float switch 24 Heater 25 Redox potentiometer 2501 Electrode part 26 Operation switch 27 Power supply

Claims (6)

An automatic denitrification system for closed water areas,
A denitrification circulation tank (7) for taking in the water in the closed water area (2) and reducing nitric acid contained in the taken-in water to convert it into nitrogen gas;
Water filling means (13) for taking the water in the closed water area (2) into the denitrification circulation tank (7);
A circulation means (16) for circulating water in the denitrification circulation tank (7);
Extrusion means (20) for returning the water in the denitrification circulation tank (7) to the closed water area (2);
A water level detection means (23) disposed in the denitrification circulation tank (7) for detecting the water level in the denitrification circulation tank (7);
A heater (24) disposed in the denitrification circulation tank (7);
An oxidation-reduction potentiometer (25) disposed in the denitrification circulation tank (7) for measuring the oxidation-reduction potential of water in the denitrification circulation tank (7);
Control means (22) for controlling the operation of the entire system,
The denitrification circulation tank (7)
The denitrification area (10) for reducing the inside of the closed system water area (2) by the partition plate (8) and reducing the nitric acid contained in the taken water into nitrogen gas by the partition plate (8); The water that has passed through the denitrification area (10) is divided again into a circulation area (11) for circulation to the denitrification area (10),
In the denitrification area (10), there are a bacteria implantation part (1201) for implanting anaerobic bacteria, and a biodegradable polymer (1202) as a nutrient of the anaerobic bacteria, The denitrification part (12) which reduced the nitric acid contained in water by making the water containing nitric acid pass, and was able to convert it into nitrogen gas was provided,
The partition plate (8) has a communication part (9) in which the denitrification area (10) and the circulation area (11) communicate with each other in the lower part, and the water that has passed through the denitrification part (12). Can be moved to the circulation area (11),
The water filling means (13) takes in water in the closed water system (2) into the denitrification area (10) of the denitrification circulation tank (7),
By circulating the water taken into the denitrification area (10) by the circulation means (16) between the circulation area (11) and the denitrification area (10) while passing through the denitrification section (12). The nitric acid contained in the water taken into the denitrification area (10) is reduced and converted to nitrogen gas,
An automatic denitrification system for a closed water system that enables the water in the denitrification circulation tank (7) not containing nitric acid to be returned to the closed water system (2) by the extrusion means (20).   The operation of the water filling means (13), the circulation means (16), and the pushing means (20) is automatically controlled by the control means (22). Automatic denitrification system.   When the control means (22) controls that the water level detection means (23) detects that the water level in the denitrification circulation tank (7) has dropped to a preset value, the water filling means (13) The automatic denitrification system for closed system water areas according to claim 2, wherein water in the closed system water area (2) is taken into the denitrification circulation tank (7) by means of the above. Based on the control of the control means (22), based on the redox potential of water in the denitrification circulation tank (7) by the redox potentiometer (25),
When it is determined that nitric acid is present in the water in the denitrification circulation tank (7), the circulation means (16) causes the water in the denitrification area (10) to be denitrified ( 12) circulate between the circulation area (11) and the denitrification area (10) while passing through
When it is determined that nitric acid is not present in the water in the denitrification circulation tank (7), the extrusion means (20) causes the water in the denitrification circulation tank (7) to be closed in the closed water area (2). The automatic denitrification system for closed water bodies according to claim 2, wherein The circulation means (16) is for returning the water that has passed through the denitrification section (12) in the denitrification area (10) to the denitrification area (10) again.
A submersible pump (17) disposed in the circulation area (11);
A circulation channel (18) having a base end connected to the submersible pump (17) and a tip communicating with the denitrification area (10), and a three-way valve (19) interposed in the path. And comprising
The water filling means (13) includes a water filling channel (14) having a proximal end communicating with the closed water body (2) and a distal end communicating with the denitrification area (10), and the water filling channel ( 14) a pump for intake (5) for taking water from the closed water area (2) into the denitrification area (10) via 14),
The extrusion means (20) has a distal end communicating with the closed water body (2) and a proximal end connected to the circulation passage (18) via the three-way valve (19). )
When the water in the closed system water area is taken into the denitrification circulation tank (7), the water in the closed water area (2) is denitrified through the water filling channel (13) and the intake pump (5). Into the circulation tank (7),
When circulating the water in the denitrification circulation tank (7), the circulation area (11) and the denitrification area (10) are switched via the circulation channel (18) by switching the three-way valve (19). The water in the denitrification circulation tank (7) is denitrified with the circulation area (11) via the submersible pump (17) and the circulation channel (18) while passing through the denitrification section (12). Circulate between areas (10)
When returning the water in the denitrification circulation tank (7) to the closed system water area (2), the three-way valve (19) is switched from the proximal end of the circulation channel (18) by switching the three-way valve (19). To the extrusion flow path (20), the submersible pump (17), the part from the proximal end to the three-way valve (19) in the circulation flow path (18), and the extrusion flow The closed system water area according to any one of claims 1 to 4, wherein water in the denitrification circulation tank (7) is pushed out to a closed system water area (2) through a flow path (20). Automatic denitrification system.   The automatic denitrification system for a closed water system according to any one of claims 1 to 5, wherein the biodegradable polymer (1202) provided in the denitrification section (12) is a polymer derived from vegetable oil. .

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