JP2022061133A - Biological reaction device used for water treatment, water bottom purifying device using the same, and aquaponics apparatus - Google Patents

Abstract

To provide a biological reaction device capable of purifying water at high speed by performing simultaneous treatments with aerobic bacteria and with anaerobic bacteria.SOLUTION: A biological reaction device 1 includes: a filter medium 2; purifying bacteria grown in the filter medium 2; treated water introducing and discharging means 3 and 4 through which treated water is introduced into the biological reaction device 1, flows inside the filter medium 2, and is discharged; and aeration means 5. The purifying bacteria include Bacillus subtilis, nitrifying bacteria, and denitrifying bacteria. The Bacillus subtilis, the nitrifying bacteria or nitrifying archaebacteria, and the denitrifying bacteria grow in the same filter medium 2. The filter medium 2 is immersed in the treated water, and nitrifying and denitrifying of nitride contained in the treated water are simultaneously conducted in the same filter medium 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a biological reaction apparatus that can be used for treatment of sewage and clean water, or various other water treatments. It is also an invention relating to a water bottom purification device using the above-mentioned biological reaction device for purifying the water bottom on which organic matter is deposited.

Advanced water purification is performed by combining physical purification and purification using a biological reaction device using microorganisms such as bacteria. In purification using a biological reaction device, the removal of organic substances and the removal of nitrogen compounds such as ammonia and nitric acid are mainly performed.

In sewage treatment, the removal of ammoniacal nitrogen is particularly important. In the most common sewage treatment, the biological reactor consists of two filtration tanks, an aerobic tank with a high dissolved oxygen concentration and an anaerobic tank with a low dissolved oxygen concentration.
For example, a wastewater treatment device including an anaerobic filter bed tank 1 (anaerobic tank) that decomposes organic matter by anaerobic bacteria and a contact aeration tank 2 (aerobic tank) that decomposes organic matter by aerobic bacteria has been proposed. (For example, Patent Document 1).

In addition, a single-layer septic tank that doubles as an aerobic tank and an anaerobic tank has been developed for the purpose of downsizing the equipment and simplifying the processing.
For example, by controlling the operation of the blower 7 and changing the dissolved oxygen concentration over time to create an aerobic state and an anaerobic state alternately, treatment with aerobic bacteria and anaerobic bacteria is realized in one tank. (For example, Patent Document 2 and Patent Document 3).

Aerobic and anaerobic bacteria are propagated in different floating filter media, a filter medium for aerobic bacteria with a heavy specific density is suspended in the lower part of the tank, and a filter medium for aerobic bacteria with a heavy specific density is suspended in the upper part, and aeration means in the middle. There is also an example in which (aeration means) is provided and the water to be treated is made into an ascending stream to create an aerobic state and an anaerobic state in one tank, and treatment with aerobic bacteria and anaerobic bacteria is realized (for example). Patent Document 4).

Japanese Patent Application Laid-Open No. 4-298290 Japanese Patent Application Laid-Open No. 11-165190 JP-A-6-328099 JP 2001-269688

The biological reaction apparatus described in Patent Document 1 requires two filtration tanks, an aerobic tank and an oxygen-free tank, and also requires complicated return control of the amount of activated sludge and sludge treatment. Therefore, there are various problems that the device configuration becomes complicated, the device becomes large, and the processing time becomes long.

In the method described in Patent Document 2 and Patent Document 3 in which the dissolved oxygen concentration is changed over time by so-called intermittent aeration, the amount of aeration is made highly accurate so that aerobic bacteria and anaerobic bacteria are sufficiently activated. Need to be adjusted. Since the optimum amount of aeration changes depending on the degree of contamination of the water to be treated, the water temperature, etc., an advanced control system is required. Further, since the treatment with aerobic bacteria and the treatment with anaerobic bacteria are alternately performed, the purification efficiency is not high.

The same applies to the method of changing the dissolved oxygen concentration depending on the location described in Patent Document 4, and advanced control of the aeration amount is required. Further, the treatment with anaerobic bacteria is performed on the upstream side of the flow of the water to be treated, and the treatment with aerobic bacteria is performed on the downstream side. The treatment with anaerobic bacteria is a treatment for reducing and denitrifying nitrite and nitric acid generated by the treatment with aerobic bacteria. Therefore, since the processing direction is opposite to the progress of the reaction, the processing efficiency as a whole is lowered.

Therefore, in each of the methods described in Patent Documents 2 to 4, treatment with aerobic bacteria and treatment with anaerobic bacteria are performed separately.
The present invention has been made to solve the above-mentioned problems, and simultaneously performs treatment with aerobic bacteria and treatment with anaerobic bacteria, which could not be realized in the past. This enables high-speed water purification that is unmatched in the past.

The biological reaction apparatus used for water treatment according to the present invention is
With filter media
Purifying microorganisms that grow on the filter media and
The introduction route that guides the water to be treated to the filter medium and
A drainage route for draining the water to be treated that has come into contact with the filter medium,
It is equipped with an aeration means for supplying oxygen to the water to be treated guided by the filter medium.
The purifying microorganisms are Bacillus subtilis and nitrifying bacteria, which are aerobic microorganisms, and denitrifying bacteria, which are anaerobic microorganisms.
The above Bacillus subtilis, nitrifying bacteria, and denitrifying bacteria grow in the same filter medium and
The nitrogen compound contained in the water to be treated is nitrified and denitrified at the same time.

Further, the water bottom purification device according to the present invention includes the biological reaction device used for the above water treatment and the above-mentioned biological reaction device.
An ascending current generating means that sends water to be treated to the biological reaction device,
It is equipped with.

Since the biological reaction apparatus used for the water treatment of the present invention is configured as described above, nitrification and denitrification of the nitrogen compound can be performed at the same time. As a result, nitrification and denitrification can be performed at an extremely high speed as compared with a conventional biological reaction apparatus.
Therefore, it is possible to increase the speed and efficiency of water treatment.
Further, since the device configuration is simple, the device can be miniaturized.

In addition, the generation of excess activated sludge is small, and the cost of treating excess sludge can be reduced. Furthermore, since nitrification and denitrification proceed at the same time, the water to be treated is not biased to the acidic side. Therefore, it is not necessary to add alkali for neutralization, and the cost and labor of pH adjustment are not required.

It is an internal permeation side view of the biological reaction apparatus used for the water treatment of this invention. It is an internal permeation side view of the biological reaction apparatus used for water treatment of this invention, and shows the case where the aeration means is arranged on the downstream side. This is an experimental result showing the dependence of the water quality treated by the biological reactor used for the water treatment of the present invention on dissolved oxygen, and is a case where the aeration means is arranged on the upstream side. This is an experimental result showing the dependence of the water quality treated by the biological reactor used for the water treatment of the present invention on dissolved oxygen, and is a case where the aeration means is arranged on the downstream side. This is an experimental result showing the particle size dependence of the water quality filter medium treated by the biological reaction apparatus used for the water treatment of the present invention. It depends on the acclimatization period of the water quality treated by the biological reaction apparatus used for the water treatment of the present invention. It is a reference figure, and it depends on the acclimatization period of water quality when Bacillus subtilis is not propagated. It is an internal permeation side view of the biological reaction apparatus used for the water treatment of Embodiment 2 of this invention. It is a side view of the water bottom purification apparatus of Embodiment 3 of this invention. It is a side view of the aquaponics apparatus of Embodiment 4 of this invention.

The biological reaction apparatus used for water treatment of the present invention can be used for various water treatments such as sewage treatment, clean water treatment, agricultural wastewater and livestock wastewater treatment, that is, water purification.
As with the conventional biological reaction device, it is intended to be used in combination with physical filtration, chemical treatment, and the like. Of course, depending on the application, water can be purified by itself.

Although some good embodiments will be described below, the present invention is not limited to these embodiments, but includes a wide range of similar invention concepts.
First, in the first embodiment, the basic requirements of the biological reaction apparatus used for the water treatment of the present invention will be described with a focus on a fixed filter medium configuration. Next, in the second embodiment, the flow filter medium configuration will be mainly described. Then, in the third embodiment, as an application of the biological reaction apparatus used for the water treatment of the present invention, a method for removing organic substances deposited on the bottom of the water will be described.

Embodiment 1.
<Structure>
FIG. 1 is an internal permeation side view of the biological reaction apparatus used for the water treatment of the present invention.
As shown in FIG. 1, the biological reaction device 1 used for water treatment according to the present invention includes a filter medium 2, a purifying microorganism that grows on the filter medium 2, an introduction route 3 that guides water to be treated to the filter medium 2, and a filter medium 2. It is provided with a drainage path 4 for draining the water to be treated that comes into contact with the filter medium 2, and an aeration means 5 for supplying oxygen to the water to be treated guided to the filter medium 2. The water to be treated is introduced into the biological reaction device 1 from the introduction path 3, flows through the filter medium 2, and is drained from the drainage path 4.

The filter medium 2 may be any as long as it can propagate microorganisms. For example, gravel, gravel, resin, ceramic and the like are suitable. The filter medium 2 is immersed in the water to be treated. Alternatively, even if the filter medium 2 is not completely immersed in the water to be treated, the water to be treated may be dropped on the filter medium 2 like a shower.

Purifying microorganisms are Bacillus subtilis, nitrifying bacteria, and denitrifying bacteria, and grow in the same filter medium 2.
Here, Bacillus subtilis is an aerobic bacterium, and is Bacillus subtilis or Bacillus natto (Bacillus subtilis var. Natto).
Nitrifying bacteria are aerobic bacteria, nitrite bacteria (ammonia-oxidizing bacteria) and nitrifying bacteria (nitrite-oxidizing bacteria). Nitrifying bacteria are bacteria that oxidize ammonia in the soil to nitrite (ammonia responsible bacteria) or archaea (ammonia correctly archaea). Nitrate bacteria are bacteria that oxidize nitrite to nitric acid.

Denitrifying bacteria are facultative anaerobic bacteria, which have the effect of reducing nitric acid HNO3 or nitrite HNO2, converting them into nitrogen gas and releasing them into the air, and are also called denitrifying bacteria.

It is a major point of the present invention that by growing (propagating) Bacillus subtilis, nitrifying bacteria, and denitrifying bacteria in the same filter medium 2, a cooperative relationship between them is created. When grown in the same filter medium 2, these purifying microorganisms are considered to propagate in the optimum location in the filter medium 2 so that each can work most efficiently. Therefore, each can work cooperatively with each other. That is, a synergistic and highly efficient purification reaction may occur. In particular, if the nitrification reaction and the denitrification reaction occur at the same time, there is a possibility that the nitrogen compound can be converted into nitrogen gas with very high efficiency. Further, at this time, the organic matter oxidation reaction by Bacillus subtilis may accelerate the nitrification and denitrification reactions.

The aeration means 5 introduces oxygen into the water to be treated by using a pump, an air diffuser, or the like. Pure oxygen may be introduced or air may be introduced. Alternatively, it may be a fine bubble of air or oxygen. In FIG. 1, the aeration means 5 is described in the biological reaction device 1, but before introducing the water to be treated into the biological reaction device 1, for example, another water tank is provided, and the water to be treated is provided there. Oxygen may be dissolved. Therefore, the aeration means 5 does not necessarily have to be in the biological reaction device 1.

<Verification experiment>
Several experiments were conducted to verify the performance of the biological reactor used for the water treatment of the present invention. In the following, these experimental conditions and experimental results will be described in detail.

(Verification experiment 1)
The water tank of the biological reaction device 1 was a water tank having a length and width of 1 m and a height of 1 m and 20 cm, and about 1 ton of water to be treated was put in the water tank. Then, the water to be treated was introduced at a flow rate of 150 L / min and drained.
As the water to be treated to be introduced into the biological reaction apparatus 1, relatively dirty river water was used, and ammonium sulfate was mixed with the water to bring the ammonia nitrogen concentration to 10 mg / L.

As the filter medium 2, sand having an average particle size of 3 mm was used. The total volume of sand is 300L. By continuing to run the water to be treated for one month, Bacillus subtilis, nitrifying bacteria, and denitrifying bacteria were propagated and acclimatized to this filter medium 2.

Nitrogen gas is introduced into the water to be treated in advance to make the dissolved oxygen concentration (DO) almost zero, and the aeration amount of the aeration means 5 is changed to change the dissolved oxygen concentration of the water to be treated in the biological reaction apparatus 1. Changed. The dissolved oxygen concentration was measured in the vicinity of the aeration means 5. That is, the dissolved oxygen concentration of water before the oxygen was consumed by the purifying microorganism was measured.
As shown in FIG. 1, the aeration means 5 was arranged on the upstream side (introduction path 3 side) of the flow of the water to be treated with respect to the filter medium 2, and the dissolved oxygen concentration was measured at the location indicated by A.
For comparison, a similar experiment was also performed by changing the position of the aeration means. As shown in FIG. 2, the aeration means 5a was arranged on the downstream side (drainage path 4 side) of the flow of the water to be treated with respect to the filter medium 2, and the dissolved oxygen concentration was measured at the location indicated by B.

The water quality was determined by the rate of removal of nitrogen compounds in the water drained from the treated water drainage means 4. That is, it was evaluated by measuring the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen.
The water temperature of the water to be treated is 25 ° C.

FIG. 3 shows the water quality evaluation result when the aeration means is arranged on the upstream side of the flow of the water to be treated with respect to the filter medium 2 (in the case of FIG. 1), and FIG. It is a water quality evaluation result when it is arranged on the downstream side of the flow (in the case of FIG. 2). The horizontal axis is the dissolved oxygen concentration, and the vertical axis is the concentration of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in wastewater (water after purification).

Regardless of whether the aeration means is arranged on the upstream side or the downstream side, the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen show the same tendency with respect to the dissolved oxygen concentration, and are 5 mg / L. It showed a low concentration between the saturated dissolved oxygen concentrations. That is, good water quality improvement was achieved at high dissolved oxygen concentration.

However, it was found that when the aeration means was arranged on the upstream side, the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen were lower, and the effect of improving water quality was greater. When the aeration means is placed on the upstream side and the dissolved oxygen concentration is set from 5 mg / L to the saturated dissolved oxygen concentration, ammonia nitrogen and nitrite nitrogen are hardly detected, and nitrate nitrogen is also extremely low. rice field.

In addition, this result indicates that nitrification and denitrification of the nitrogen compound are performed at the same time. If only nitrification is done, nitrite and nitric acid should remain in high concentrations. However, the low concentration of nitrite and nitric acid in the one-pass treatment without circulating the water to be treated indicates that nitrification and denitrification are proceeding at the same time. When nitrification and denitrification proceed at the same time, the important result is that the higher the dissolved oxygen concentration, the higher the efficiency of nitrification and denitrification.

(Verification experiment 2)
Next, the dissolved oxygen concentration was fixed at 7 mg / L, the average particle size of the filter medium 2 was changed from 0.2 mm to 18 mm, and how the average particle size of the filter medium 2 affected the improvement of water quality was investigated. .. The arrangement of the aeration means 5 is on the upstream side.
Other conditions are the same as in Verification Experiment 1.

FIG. 5 shows the experimental results.
Good results were obtained with an average particle size of 1 mm to 10 mm. Regarding the average particle size of the filter medium 2, it was confirmed that a good water quality improving effect can be obtained in such a fairly wide range.

(Verification experiment 3) (Experiment to show the effect of symbiotic Bacillus subtilis on the same filter medium)
Nitrogen compounds are generally removed by nitrifying bacteria and denitrifying bacteria, but in order to confirm whether Bacillus subtilis plays an auxiliary role, whether or not there is a difference in water quality depending on the presence or absence of Bacillus subtilis reproduction. We also conducted a verification experiment.

Aeration was performed on the upstream side, and the dissolved oxygen concentration was set to 7 mg / L. The average particle size of the filter medium was 3 mm. Changes in water quality from the start of breeding of purified microorganisms were investigated for the water quality when Bacillus subtilis was propagated in the filter medium 2 and when only nitrifying bacteria and denitrifying bacteria were propagated without Bacillus subtilis. That is, we investigated how the water quality changes during and after the acclimatization period of purified microorganisms.

FIG. 6 shows water quality data when Bacillus subtilis, nitrifying bacteria, and denitrifying bacteria are propagated in the filter medium 2, and the horizontal axis shows the period from the start of propagation. In the 4th week from the start of breeding, ammonia nitrogen and nitrite nitrogen almost disappeared, and the concentration of nitrate nitrogen became low. The water quality was good even after 4 weeks from the start of breeding.

FIG. 7 is water quality data when only nitrifying bacteria and denitrifying bacteria are propagated in the filter medium 2. Ammonia nitrogen was detected until the 8th week, and the concentration became low after the 10th week. The concentration of nitrite became low at the 10th week, but it did not disappear completely, and about 0.2 mg / L was detected after the 10th week.

As described above, it was found that there is a clear difference in both the acclimatization period and the water quality depending on the presence or absence of Bacillus subtilis. It was confirmed that a cooperative relationship was obtained, the acclimatization period could be shortened, and the water quality was improved.

<Summary of this embodiment>
As described above, it was confirmed that the biological reaction apparatus used for water treatment of the present invention can purify water, particularly remove nitrogen compounds at extremely high speed.

A characteristic configuration in the present invention is to grow three kinds of purifying microorganisms in one filter medium. It is thought that this is because each microorganism propagates in the place and situation where it can work most efficiently, so that the three kinds of purifying microorganisms cooperate with each other to perform water treatment.

The details of the cooperative relationship are unknown, but for example, regarding the relationship between Bacillus subtilis and nitrifying bacteria, when Bacillus subtilis decomposes dissolved organic matter, the concentration of dissolved organic matter, which is an inhibitor of the nitrification reaction performed by nitrifying bacteria, is low. It is thought that nitrification occurs with high efficiency. In addition, Bacillus subtilis generates carbon dioxide when it decomposes dissolved organic matter, and nitrifying bacteria can use this carbon dioxide to synthesize proteins and promote their reproduction.
Further, regarding the relationship between Bacillus subtilis and denitrifying bacteria, the dissolution of suspended organic matter by Bacillus subtilis sufficiently provides the hydrogen donor necessary for the denitrifying bacteria to carry out the denitrification reaction.

It can be imagined that the above-mentioned cooperative relationship actually progresses in a more complicated manner among the three types of purifying microorganisms, and extremely high-speed water treatment is performed. Such a cooperative relationship is made because three kinds of purifying microorganisms coexist in one filter medium.

Another characteristic of the present invention is that not only nitrification but also denitrification is performed at high speed at a high dissolved oxygen concentration of 5 mg / L or more. In the conventional water treatment system, nitrification had to be performed under a high oxygen concentration and denitrification had to be performed under anoxic or extremely low oxygen concentration, which overturns the common wisdom. It is considered that this is because nitrification and denitrification do not occur separately, but proceed at the same time, that is, as a continuous reaction.

With such a characteristic configuration of the present invention, a water treatment apparatus having many features described below could be realized.
First, high-speed nitrification and denitrification, which were unthinkable in the past, could be realized at the same time. This makes it possible to reduce the size of the equipment and significantly reduce the cost of the water treatment facility. It can also be used as a water purification system for households and small groups.
Furthermore, since nitrification and denitrification proceed at the same time, the water to be treated is not biased to the acidic side. Therefore, no alkali is required for neutralization.

Second, there is no need for advanced control of aeration. Since denitrification can be performed under the same high dissolved oxygen concentration as nitrification, fine control is not required. If sufficient oxygen can be supplied to the water to be treated, nitrification and denitrification can proceed at high speed.

Thirdly, the purified microorganism is a filter medium fixed type, and compared with the floating type activated sludge method, almost no surplus sludge is generated. Therefore, the treatment cost of excess sludge, which occupies a large cost in the conventional water treatment, is significantly reduced. In addition, since the configuration of returned sludge and the like is not required, the cost of the equipment can be reduced and the management can be simplified.

As described above, the present invention has various advantages necessary for a water treatment device, such as speeding up water treatment, downsizing of the device, reduction of device cost and running cost, and simplification of management.

Embodiment 2.
The biological reaction apparatus used for the water treatment of the second embodiment will be described with reference to FIG. FIG. 8 is an internal permeation side view of the biological reaction apparatus 10.
In the first embodiment, the purified microorganisms were propagated on the fixed filter medium, but in the present embodiment, the purified microorganisms were propagated on the filter medium 20 flowing in the water to be treated.

The filter medium has fine pores such as polyethylene glycol, polyvinylformal, foamed ethylene, urethane, pumice and other volcanic debris, and can be made of any material that has a specific density equal to or slightly higher than that of water. The material may be used.
The size of the filter medium is about several mm to several cm in diameter.
It is desirable that the micropores have a diameter of about 0.5 mm to 2 mm. Micropores of this size are good for breeding Bacillus subtilis, nitrifying bacteria, and denitrifying bacteria.

The filter medium 20 in which Bacillus subtilis, nitrifying bacteria, and denitrifying bacteria are propagated is allowed to flow in the water to be treated. The water to be treated is introduced into the biological reaction apparatus 10 from the introduction route 30 and discharged from the discharge route 40. An aeration means 50 is provided in the lower part of the biological reaction device 10. The aeration means 50 is, for example, an air diffuser, and air and oxygen are released in the form of bubbles. The buoyancy of the bubbles causes the filter media 20 to flow. That is, the means for flowing the filter medium 20 is an air lift using an aeration means.

The flow of the filter medium 20 in the water to be treated increases the chances of contact between the water to be treated and the purifying microorganisms that propagate in the filter medium 20, and the water to be treated is efficiently purified.

When the water to be treated is seawater, the suspended organic matter is efficiently removed by removing the bubbles adhering to the surface from the foam separating means 80 provided on the upper part of the biological reaction device 10. It is also possible.

Further, by putting Bacillus subtilis var. Natto into the biological reaction apparatus 10, the removal of organic matter is promoted. This is because Bacillus natto releases γ-polyglutamic acid, which has a fibrous structure and aggregates suspended organic matter. If the aeration means 50 is stopped, the agglomerated Bacillus natto will settle in the sediment accumulation section 70 provided at the bottom of the biological reaction device 10, and the valve V3 can be opened and discharged.

(Verification experiment 4)
4 m3 of water collected from the pond where domestic wastewater was accumulated was stored in the tank and purified. The main water quality of the water before purification was as follows.

COD (Chemical Oxygen Demand): 50 mg / L
SS (suspended organic matter): 55 mg / L
Ammonia nitrogen: 20 mg / L
Nitrate nitrogen: 0.5 mg / L
Nitrate nitrogen: 2 mg / L

Nitrifying bacteria, denitrifying bacteria and Bacillus subtilis were propagated in advance using Hinata stone with an average diameter of 1 cm as a filter medium. Then, a filter medium of about 1.5 m3 was put in a tank for purification. The amount of aeration is 50 L / min, and the flow rate of the water to be treated is 50 L / min.

The water quality after purification is as follows.

COD (Chemical Oxygen Demand): 20 mg / L
SS (suspended organic matter): 26 mg / L
Ammonia nitrogen: 1 mg / L
Nitrate nitrogen: 2.8 mg / L
Nitrate nitrogen: 4 mg / L

As described above, it was found that the water quality was improved and that even when the filter medium was flowed, the water quality was improved as in the case of the fixed filter medium.

(Verification experiment 5)
A purification experiment was conducted by flowing the filter medium in the same manner as in the verification experiment 4. The difference from the verification case 4 is that 10 cc / min of natto bacteria was added from the upper part 80 of the tank.

The water quality after purification is as follows.

COD (Chemical Oxygen Demand): 3 mg / L
SS (suspended organic matter): 2 mg / L
Ammonia nitrogen: below the detection limit nitrite nitrogen: 0.3 mg / L
Nitrate nitrogen: 4 mg / L

In this way, by adding Bacillus natto, the water quality was further improved, and it was confirmed that both organic matter and inorganic nitrogen were significantly reduced.

<Summary of this embodiment>
As can be seen from the above results, even if a fluid filter bed (fluid carrier) is used, highly efficient purification is possible as in the case of the fixed filter bed shown in the first embodiment. In particular, it was confirmed that the addition of Bacillus natto can improve not only the removal of organic matter but also the efficiency of nitrification and denitrification.

Embodiment 3.
The water bottom purification device of the third embodiment will be described with reference to FIG. It is a device that performs particularly effective purification in the water area where organic matter is deposited on the bottom of the water, and is a device that aims to reduce the thickness of the deposited organic matter and improve the purification environment of the bottom of the water.

The ascending current generating means 600 is used to wind up the deposited organic matter 700 and guide the water to be treated to the biological reaction device 100 used for water treatment. It is desirable that the aeration means 500 is provided near the bottom of the water, but dissolved oxygen near the surface of the water may be supplied to the vicinity of the bottom by a downward flow from the surface of the water.

The ascending current generating means 600 is, for example, a pump or a screw, and may have any mechanism as long as it is possible to gradually wind up the deposited organic matter by making the vicinity of the surface of the deposited organic matter a negative pressure. good.

As shown in FIG. 9, the biological reaction device 100 used for water treatment can fix or flow the filter medium 200 inside. Nitrifying bacteria, denitrifying bacteria and Bacillus subtilis are propagated in the filter medium 200.

By using the device having such a configuration, the deposited organic matter on the bottom of the water can be gradually reduced in thickness. Further, by introducing the wound organic matter into the biological reaction apparatus 100 used for water treatment, the suspended organic matter, the dissolved organic matter, and the inorganic nitrogen can be significantly reduced.

<Summary of this embodiment>
Thick organic matter is deposited on the bottom of rivers, coastal areas, bays, lakes, ponds, etc., which is a major factor in the deterioration of water quality.
Although the deposited organic matter is also removed by dredging, it is not a fundamental measure because the organic matter is deposited again after dredging, despite the enormous removal cost.

On the other hand, although the method of hoisting the deposited organic matter with a pump or a screw can be performed at a relatively low cost, the hoisted organic matter diffuses to the surroundings, which may expand the contaminated area.

In the present embodiment, by guiding the water to be treated containing the wound organic matter to the biological reaction apparatus used for the water treatment shown in the first and second embodiments, the biological purification is performed before the organic matter diffuses to the surroundings. be able to. Since the biological reaction apparatus used for water treatment of the present invention has high purification efficiency, even treated water containing a high concentration of organic substances and inorganic nitrogen can be treated to good water quality.

Embodiment 4.
Recently, research is progressing on aquaponics that combines aquaculture and hydroponics. In aquaponics, the breeding water of aquatic organisms is used as a nutrient solution for plants, and the nutrient solution used for plants is recycled as breeding water again.
Ammonia, which is a highly toxic substance contained in the excrement of aquatic organisms, is oxidized by nitrifying bacteria to become weakly toxic nitrite and nitric acid. Nitrous acid and nitric acid are weakly toxic, but when they accumulate in breeding water and become high in concentration, they adversely affect the health of aquatic organisms. However, breeding water containing nitrite and nitric acid becomes a nutrient solution for plants, and nitrite and nitric acid are absorbed from the roots of plants and used for photosynthesis. This makes it possible to avoid the accumulation of nitrite and nitric acid. In this way, the basic idea of aquaponics is that nitrite and nitric acid, which are toxic to aquatic organisms, are consumed by photosynthesis of plants, resulting in good circulation of water.

However, in reality, such ideal water circulation is difficult, and there are few examples of realizing aquaponics on a commercial basis.
One of the major problems is that nitrite and nitric acid generated in the breeding tank are not sufficiently absorbed by plants, so that nitrite and nitric acid accumulate in the long term, which is harmful to the health of aquatic organisms. When aquaculture is carried out on a commercial basis, aquatic organisms are bred at a fairly high density. Therefore, the amount of excretion of aquatic organisms is large, and the amount of nitrite and nitric acid generated is also considerable. In order for plants to absorb this large amount of nitrite and nitric acid, a plant cultivation area that is much larger than that of aquatic organism breeding tanks is required, so it can be realized on a commercial basis from the viewpoint of space efficiency. It will be difficult.
In addition, many of the aquatic organisms with high added value commercially are marine fish. Therefore, the breeding water becomes salt water and is not suitable as a nutrient solution for plants.
The above two issues are major obstacles to the realization of aquaponics on a commercial basis.

FIG. 10 is an example of aquaponics using the biological reaction apparatus shown in the first or second embodiment. The water in the breeding tank 3000 where the fish grows is pumped up to the biological reaction device 1000 by the pump P. The pumped water is purified by the purifying microorganisms growing on the filter medium 2000, and is flushed to the planter 4000 on which the plants grow. Then, the water used as a nutrient solution for the plant in the planter 4000 returns to the breeding tank 3000.
The point in this embodiment is that water containing a large amount of fish excrement is purified with high efficiency in the biological reaction device 1000. As shown in Embodiments 1 and 2, nitrification and denitrification occur with high efficiency, so that the concentration of nitrite or nitric acid is low. Therefore, even in a planter with the same area as the breeding tank, the remaining nitrite and nitric acid are sufficiently consumed by the plants.
In addition, since the nitrite concentration of the circulating water is maintained at a very low concentration, it becomes possible to reduce the salt concentration of the water to a brackish water level. Marine fish grow faster at brackish water levels because the load of osmoregulation is smaller. However, since nitrite and chloride ions become competing substances when absorbed from gills, if the salt concentration is low, the amount of nitrite absorbed increases, and respiratory disorders and the like are likely to occur. However, in the biological reactor 1000, high-efficiency purification is performed and the nitrite concentration is always kept low, so that such a disorder does not occur even with brackish water level salt water.

As described above, by using the biological reaction apparatus shown in Embodiments 1 and 2, the two problems of conventional aquaponics can be solved or alleviated, so that aquaponics on a commercial basis can be realized. It will be easier.

1 Biological reactor 2 Filter media 3 Treatment water introduction means 4 Treatment water drainage means 5 Aeration means

10 Biological reactor 20 Filter media (fluid filter media)
30 Treated water introduction means 40 Treated water drainage means 50 Aeration means

100 Biological reactor 200 Filter media 500 Aeration means 600 Upflow generation means

The biological reaction apparatus used for water treatment according to the present invention is
With filter media
Purifying microorganisms that grow on the filter media and
The introduction route that guides the water to be treated to the filter medium and
A drainage route for draining the water to be treated that has come into contact with the filter medium,
It is equipped with an aeration means for supplying oxygen to the water to be treated guided by the filter medium.
The purifying microorganisms are Bacillus subtilis, which is an aerobic microorganism that decomposes dissolved organic substances , nitrifying bacteria, which are aerobic microorganisms that perform a nitrification reaction , and denitrifying bacteria, which are anaerobic microorganisms that perform a denitrification reaction .
The above Bacillus subtilis, nitrifying bacteria, and denitrifying bacteria grow in the same filter medium and
The nitrogen compound contained in the water to be treated is nitrified and denitrified at the same time.

Further, the filter medium is a fixed bed, and the dissolved oxygen concentration of the water to be treated on the introduction path side of the filter medium is 5 ppm or more and the saturated dissolved oxygen concentration or less.
Alternatively, the filter medium flows in the water to be treated, and the dissolved oxygen concentration of the water to be treated is 5 ppm or more and is not more than the saturated dissolved oxygen concentration. Further, it has a means for inputting natto bacteria to input natto bacteria.

Claims (10)

A biological reaction device used for water treatment
With filter media
Purifying microorganisms that grow on the filter media and
The introduction route that guides the water to be treated to the filter medium and
A drainage route for draining the water to be treated that has come into contact with the filter medium,
It is equipped with an aeration means for supplying oxygen to the water to be treated guided by the filter medium.
The purifying microorganisms are Bacillus subtilis and nitrifying bacteria, which are aerobic microorganisms, and denitrifying bacteria, which are anaerobic microorganisms.
The above Bacillus subtilis, nitrifying bacteria, and denitrifying bacteria grow in the same filter medium and
A biological reaction device used for water treatment that simultaneously nitrifies and denitrifies the nitrogen compound contained in the water to be treated. The biological reaction apparatus used for water treatment according to claim 1, wherein the filter medium is a fixed bed, and the aeration means is arranged on the upstream side of the flow of the water to be treated with respect to the filter medium. .. The biological reaction apparatus used for water treatment according to claim 1 or 2, wherein the dissolved oxygen concentration of the water to be treated on the introduction path side of the filter medium is 5 ppm or more and the saturated dissolved oxygen concentration or less. The biological reaction apparatus used for water treatment according to claim 1, wherein the filter medium flows in the water to be treated. The biological reaction apparatus used for water treatment according to claim 4, further comprising a means for inputting natto bacteria. The biological reaction apparatus used for water treatment according to claim 4 or 5, wherein the dissolved oxygen concentration of the water to be treated is 5 ppm or more and the saturated dissolved oxygen concentration or less. The biological reaction apparatus used for water treatment according to any one of claims 4 to 6, wherein the aeration means and the means for flowing the filter medium are air lift means. The biological reaction apparatus used for water treatment according to any one of claims 1 to 7.
An ascending current generating means that sends water to be treated to the biological reaction device,
Water bottom purification device equipped with. The water bottom purification device according to claim 8, further comprising a means of transportation. A breeding tank where aquatic organisms grow and
Planters where plants grow and
An aquaponics device comprising the biological reaction device according to any one of claims 1 to 7.
&#8195;

Images