JPH02268896A - Method for acclimatizing and incubating microbe for cleaning fish farming water tank such as living sea-fish preserve - Google Patents

Abstract

PURPOSE:To immediately use a fish farming water tank by charging an activated sludge-mixed liq. and blast-furnace water granulated slag into an aeration tank, supplying artificial sewage while being aerated to oxidize the ammoniacal nitrogen compd. to a nitric nitrogen compd. and successively replacing the sewage by seawater. CONSTITUTION:The liq. mixture of sewage and activated sludge and blast-furnace water granulated slag are charged into an activated sludge aeration tank provided with an oxidation reduction potential controller and a pH controller, and aerated with the oxidation-reduction potential as an index. The artificial sewage of fresh water contg. an ammoniacal compd. and an org. material capable of being decomposed by activated sludge to oxidize the ammoniacal nitrogen compd. to a nitric nitrogen compd. When oxidation proceeds until >=80% complete, the artificial sewage is successively replaced by seawater. When the >=90% of the ammoniacal nitrogen compd. is oxidized to the nitric nitrogen compd. or the water is completely replaced by seawater, the water is used for cleaning a living-fish preserve. Consequently, the module for cleaning the fish farming water tank can be immediately used.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for acclimating and cultivating aerobic and anaerobic microorganisms suitable for purifying a culture tank for seawater live fish such as Ikes.

(Conventional technology) In recent years, as eating habits have become more sophisticated, high-quality saltwater fish such as sea bream and flounder are being transported alive by trucks, railway wagons, etc., or being displayed at fish markets, fish stores, restaurants, etc. These seawater fish are often sold alive or cooked by setting up cages.

When marine fish are transported alive or reared in fish tanks, etc., harmful substances such as ammonia nitrogen compounds, sulfides, and organic substances are generated due to decomposition of fish excrement and leftover bait. The substance kills or weakens the fish. For this reason, it is necessary to install a seawater purification treatment device in the storage tanks for these fish.

Conventionally, purification treatment of aquariums such as Ikesu for live seawater fish is carried out in a purification treatment device filled with sand, gravel, coral, plastic, ceramics, etc. as a carrier for immobilizing microorganisms. A common method for purification treatment is to circulate seawater to naturally generate purifying microorganisms on the surface of the immobilized carrier.

For example, "Water Treatment Technology" (VOl, 29. NCL9.
1988, p. 29-34),
This is related to the purification treatment of aquariums in which freshwater fish are kept.
Porous ceramics are crushed and sieved, and those with a particle size of 4 to 6 in size are used as immobilization carriers for microorganisms for purification treatment of storage tanks such as Ikesu, and microorganisms are naturally generated on the surface of the porous ceramics. Fixed and purified.

The seawater in fish breeding tanks is contaminated with ammonia nitrogen compounds, sulfides, organic matter, etc. generated from fish excrement and bait leftovers. To remove these pollutants, physicochemical methods use chemicals such as oxidizing agents and flocculants, so considering the impact on fish, biochemical treatment that does not use chemicals seems more appropriate. It will be done. In other words, it is appropriate to remove ammonia nitrogen compounds by nitrification and denitrification methods, oxidize sulfides to sulfate ions, and remove organic substances by oxidative decomposition and convert them into carbon dioxide and grown sludge. Seem.

Microorganisms involved in the removal of ammonia nitrogen compounds include nitrite-oxidizing bacteria, nitrifying bacteria, and denitrifying bacteria. Among these, a method of acclimatizing and culturing nitrite-oxidizing bacteria by immobilization is known.

For example, in Japanese Patent Application Laid-Open No. 63-44995, sewage treatment is performed by immobilizing activated sludge containing nitrite-oxidizing bacteria on an inclusion immobilization carrier consisting of activated carbon and immobilized acid. That is, activated sludge containing nitrite-oxidizing bacteria is attached to an adsorbent formed by adding activated carbon to a fixed acid, and then encased in a gel of sodium alginate, carrageenan, polyacrylamide, or the like. Then, this mixture was heated under aeration of oxygen-containing gas with C.
This is a method for efficiently treating wastewater by bringing it into contact with OD components.

Furthermore, in JP-A No. 63-36898, nitrite-oxidizing bacteria were allowed to adhere to and live on a porous carrier in a culture solution, and the culture was continued by supplying nutrients to the culture solution. by acting on wastewater containing ammonia nitrogen compounds,
This is a method of oxidizing ammoniacal nitrogen compounds to nitrite.

These known methods oxidize ammonia nitrogen compounds to nitrite nitrogen compounds, and when used for purification treatment of fish breeding tanks, etc., nitrite nitrogen compounds, which are pre-nervous to fish, are This is not preferable because it generates compounds.

(Problems to be Solved by the Invention) Conventional purification treatment of culture tanks such as Ikesu for live fish has the following problems.

(1) Purification treatment involves filling the tower, reactor, etc. of the purification treatment equipment with sand, gravel, coral, plastic, ceramics, etc. as a carrier for immobilizing microorganisms, and then filling it with sand, gravel, coral, plastic, ceramics, etc. as a carrier for immobilizing microorganisms. Purification treatment is performed by circulating water and using microorganisms that naturally occur on the surface of the immobilization carrier. For this reason, it takes several days for microorganisms to appear on the surface of the immobilization carrier, during which time fish cannot be raised and microorganisms do not grow at a high density.

(2) Oxidizes ammonia nitrogen compounds, which are contaminants in fish breeding tanks, to nitrate nitrogen compounds, which are almost non-toxic to fish, without producing nitrite nitrogen compounds, which are harmful to fish. Nitrifying bacteria, especially seawater-resistant nitrifying bacteria, are not used for purification of fish storage tanks.

(3) Microorganisms, especially seawater-resistant microorganisms, that oxidize, decompose, and detoxify organic matter such as fish excrement and bait leftovers, as well as organic matter and sulfides generated by their decay, are not used.

(4) A method for acclimating and cultivating seawater-resistant nitrifying bacteria and seawater-resistant microorganisms that oxidize and decompose harmful organic matter, sulfides, etc. to render them nontoxic has not been established.

For this reason, the microorganisms involved in the purification process of the storage aquarium, such as Ikes, start the purification process immediately after being immobilized in the purification treatment equipment without acclimatization, and in order to make the purification treatment equipment more compact, the efficiency Microorganisms that can be well purified are required.

(Means for Solving the Problems) In order to solve the above-mentioned problems in the conventional purification process for aquariums, etc. established.

The present invention involves putting sewage≠activated sludge mixture and granulated blast furnace water into an aeration tank for activated sludge treatment equipped with an oxidation-reduction potential (ORP) control device and a pH control device, and using the ORP of this aeration tank as an index. Freshwater artificial sewage containing ammoniacal compounds and organic matter that can be decomposed by activated sludge is supplied to the aeration tank while aerating the air, and more than 80% of the ammoniacal nitrogen compounds are oxidized to nitrate nitrogen compounds. , The freshwater of the artificial wastewater is successively replaced with seawater, and when the ammonia nitrogen compounds in the artificial wastewater, which is 100% seawater, are finally oxidized to nitrate nitrogen compounds by more than 90%, it is used for the purification treatment of Ikesu for seawater live fish. Acclimation of aerobic microorganisms suitable for purification treatment of culture tanks such as Ikesu for seawater live fish, characterized by
Cultivation method: Put activated sludge mixture from a sewage treatment plant and granulated blast furnace water into an anaerobic reactor equipped with a stirrer, an ORP ffA control device, and a pHIII control device, and while stirring the inside of the reactor, nitrate nitrogen compounds and activated sludge are mixed. When 80% or more of the nitrate nitrogen compounds have been reduced and removed, the freshwater in the artificial sewage is gradually replaced with seawater, and finally the seawater is reduced to 100%. When 90% or more of the nitrate nitrogen compounds in artificial sewage have been reduced, it can be used for purification of culture tanks such as Ikes for seawater live fish. This is a method for acclimating and cultivating sexual microorganisms.

(Function) The present inventors removed contaminants in a breeding tank for fish, etc.
It is estimated that the waste is fish excrement, bait leftovers, organic matter, sulfides, nitrite nitrogen compounds, and ammonia nitrogen compounds produced by their decay, and that biochemical treatment methods with fewer negative effects are more suitable. Thought.

That is, when these pollutants are removed by biochemical methods, organic substances, sulfides, nitrite nitrogen compounds, and ammonia nitrogen compounds are removed by aerobic microorganisms, that is, organic substances are oxidized and decomposed into carbon dioxide and bacterial cells. First, sulfide is oxidized to sulfate ions, and nitrite nitrogen compounds and ammonia nitrogen compounds are oxidized to nitrate nitrogen compounds, which are then reduced to nitrogen gas by denitrification bacteria and removed. Appropriate.

In addition, when cultivating and culturing microorganisms that remove these pollutants, it is very time-consuming to cultivate and grow microorganisms that decompose or oxidize individual pollutants individually, so we have to distinguish between so-called aerobic microorganisms and anaerobic microorganisms. It is more advantageous to acclimatize and culture the microorganisms separately from the sexually active microorganisms.

From this perspective, the present inventors conducted research and development on a method for acclimating and cultivating microorganisms suitable for purification of aquariums, etc. Therefore, I will explain its contents.

Activated sludge from sewage consists of microorganisms that decompose organic matter, microorganisms (nitrifying bacteria) that oxidize ammonia nitrogen compounds and nitrite nitrogen compounds, and microorganisms that oxidize sulfides to sulfate compounds. It has been revealed that microorganisms that reduce nitrate nitrogen compounds to nitrogen gas (denitrifying bacteria) live there.

Therefore, the present inventors will explain the acclimatization of seawater-resistant aerobic microorganisms and anaerobic microorganisms that can be applied to the purification treatment of a storage tank for fish, etc., using activated sludge from sewage.

In order to acclimatize activated sludge from sewage to a collection of microorganisms that can be used for purification treatment in a storage tank such as Ikesu, first add p) I! to the aeration tank. The activated sludge mixture collected from the aeration tank of the activated sludge treatment equipment in the sewage treatment plant is put into an activated sludge treatment equipment equipped with an IJ control device and an ORP control device, and fine powder (20 to 200 μm) of granulated blast furnace water is added to this. 1 per aeration tank capacity
~10% by weight is added, and organic substances such as meat extract, peptone, yeast extract, and dextrin (approximately 1% as BOD) are added to this.
Treatment is carried out by supplying artificial sewage consisting of 0 to 50 μ/l and ammonium sulfate (approximately 50 μ/I as ammonia nitrogen). At this time, the amount of aeration is determined by the ORP of the aeration tank being +100 to +
It is managed and controlled to be 200 mV (Ag AgC1 electrode standard), and the pH of the aeration tank is 7.0 to 7.5 when the seawater mixing ratio is about 50% or less. If the mixing ratio is about 50% or more, 7.5 to 8
．． 0 using 5% sulfuric acid or 5% caustic soda aqueous solution.

An activated sludge treatment device equipped with an ORP control device and a pH control device for acclimating and culturing aerobic seawater-resistant microorganisms that can be applied to the purification treatment of culture tanks for saltwater fish, etc. from activated sludge of sewage, and The reason why artificial wastewater was used is as follows.

One of the inventors of the ORP control device discovered that there is a close relationship between the QRP of the aeration tank, the nitrification reaction, and the decomposition of organic matter, and the present invention also efficiently controls the nitrification reaction and decomposition of organic matter. In order to do this, the amount of aeration is managed and controlled using the ORP of the aeration tank in which aerobic microorganisms are acclimatized and cultured as an index, so it was used to control the ORP.

The 0RPIIJ control of the aeration tank in the present invention is +100~
The range of 250mV (Ag-AgCI electrode standard) is optimal, and below +100mV the nitrification reaction does not occur sufficiently, making it difficult for the nitrifying bacteria to acclimate and culture, and for ORP to be +
At 250 mV or higher, self-digestion of nitrifying bacteria and microorganisms that decompose organic matter occurs, and when the adapted nitrogen compounds of these microorganisms are oxidized to nitrate nitrogen compounds, the pH of the aeration tank decreases and activated sludge (microorganisms) In order to inhibit the function of aggregates of is about 50% or more, 7.5 to 8.0
It is used to control with 5% sulfuric acid or 5% caustic soda aqueous solution.

Next, the components of the artificial sewage used for acclimatization and culture will be explained.

First, ammoniacal nitrogen compounds were added to artificial sewage, but this caused nitrifying bacteria to oxidize the ammoniacal nitrogen compounds.
Nitrate nitrogen compounds were produced and used for growth.

The amount of ammoniacal nitrogen compounds added to artificial wastewater is such that the amount of ammoniacal nitrogen compounds produced in a culture tank such as Ikesu where saltwater fish are kept is 2 to 10% by weight (
When rearing (relative to the capacity of the storage tank for Ikes, etc.), 2
~30 μ/1 (as ammonia nitrogen), so about 50 mg/β (as ammonia nitrogen) of the ammonia nitrogen compound was added.

In addition, we used meat extract, peptone, yeast extract, dextrin, etc. as organic substances added to artificial sewage water for the cultivation and cultivation of microorganisms.
This is because it is perfect for acclimatization.

Another reason is that meat extracts contain reducing sulfur compounds, which are suitable for acclimating and cultivating microorganisms that oxidize sulfur compounds.

The appropriate concentration of these organic substances is within the range of approximately 10 to 50 .mu./2 as expressed by BOD. It is known that the nitrification reaction occurs after the decomposition of organic matter indicated by BOD is completed, and in order for the nitrification reaction to occur and the acclimatization and cultivation of nitrifying bacteria and microorganisms that decompose organic matter to occur smoothly. , this BOD range is appropriate. That is, if the BOD is less than 10 mg/f, the acclimatization and cultivation of microorganisms that decompose organic matter will not proceed smoothly, and the BO
D is 50■/! In the above case, if some BOD remains, the nitrifying bacteria will not acclimatize and culture smoothly.

Even if activated sludge from sewage is acclimatized in this way, unless all of the artificial sewage to be supplied is seawater, this activated sludge cannot be used for purification treatment of aquariums for breeding saltwater fish, etc. Therefore, it is necessary to impart seawater resistance to this activated sludge.

A method of imparting seawater resistance to activated sludge is to gradually replace the sewage fed to the activated sludge with seawater to acclimate the activated sludge to seawater, but there is an appropriate method to determine whether or not seawater resistance has been imparted. is not known.

Therefore, the present inventors focused on the function of nitrifying bacteria that oxidizes ammonia nitrogen compounds to nitrite nitrogen compounds and nitrate nitrogen compounds as a method for determining whether seawater resistance has been imparted. That is, nitrifying bacteria have a slow growth rate, and
Its function is easily inhibited by various factors, and furthermore, because of its poor settling properties, it tends to flow out of the activated sludge treatment equipment, making it extremely difficult for nitrifying bacteria to acclimatize and culture it. .

Therefore, if the raw water (in the case of the present invention, artificial sewage was used) supplied during acclimatization and culture is not suitable for the four forces of seawater, the function of nitrifying bacteria will be inhibited and the ammonia Since the oxidation rate of nitrogen compounds is thought to decrease, the degree of acclimatization of activated sludge to seawater is determined by the rate at which ammoniacal nitrogen compounds are oxidized and converted into nitrate nitrogen compounds, that is, the oxidation rate of ammoniacal nitrogen compounds. The mixing ratio of seawater was estimated from the ratio and the seawater mixing ratio was changed.

Based on this idea, we investigated the mixing ratio of seawater in artificial sewage to be supplied to activated sludge treatment, and found that if the conversion rate (oxidation rate) of ammonia nitrogen compounds to nitrate nitrogen compounds is 80% or more, It has become clear that it is possible to increase the mixing ratio of seawater in artificial sewage. Specifically, the mixing ratio of seawater in artificial sewage is approximately 1 liter of seawater in approximately 5 to 10 days.
Therefore, it takes about 5 to 10 days for the entire amount of artificial sewage to be replaced with seawater and used for the purification treatment of a breeding tank for saltwater fish such as Ikes.

Note that when the oxidation rate of ammonia nitrogen compounds is low, for example, 80% or less, if the mixing ratio of seawater in artificial sewage is increased, the function of nitrifying bacteria will be inhibited and it will take a long time to recover to a normal state.

Next, increasing the concentration of activated sludge in the present invention will be explained.

Already in the activated sludge treatment of sewage7, when granulated blast furnace water is added to the aeration tank of activated sludge treatment equipment, the activated sludge adheres to the granulated blast furnace water and the activated sludge in the aeration tank can be maintained at a high concentration.
As a result, it has been disclosed in, for example, Japanese Patent Laid-Open No. 63-42796 that highly efficient processing becomes possible.

Therefore, in the present invention, blast furnace granulation was used from the acclimatization stage to increase the concentration of microorganisms involved in the purification treatment of a storage tank for Ikesu and the like. That is, the above-mentioned mixed solution of activated sludge from the sewage treatment plant is put into an aeration tank, and a predetermined amount of granulated blast furnace granules is added at a rate of about 1% by weight per day to the capacity of the aeration tank. For example, when adding 5% by weight of blast furnace granules, the blast furnace granules are added over 5 days. At this time, artificial sewage is supplied to the aeration tank so that the treatment time is 6 to 8 hours. Note that the sludge return rate is 20 to 30%, and excess sludge is not removed during the acclimatization period to seawater.

By acclimating and culturing aerobic microorganisms that can be applied to the purification treatment of Ikesu culture tanks, etc. using this method, MLVSS (Mixed l1quar), which is an indicator of organic sludge,
volatile 5uspended 5olid
s) is approximately 1500 to 2000 ■/! at the beginning of the experiment. increased to approximately 5,000 to 7,500 μ/l at the end of acclimatization to seawater. In this way, it has been revealed that the addition of blast furnace granulation has a significant effect on the growth of organic sludge.

Another effect of blast furnace granulation is that when blast furnace granulation is used for acclimation and cultivation of aerobic microorganisms that can be applied to the purification treatment of storage tanks such as Ikesu, in addition to increasing the concentration of organic sludge, it also produces ammonia Significantly affects the ability of nitrifying bacteria to oxidize nitrogen compounds.

When culturing nitrifying bacteria, if blast furnace granulation is not used, in addition to nitrifying bacteria that oxidize ammonia nitrogen compounds to nitrate nitrogen compounds, nitrite bacteria that oxidize nitrite nitrogen compounds will also be cultured.
Multiply. Therefore, when these mixed bacteria are used to purify a storage tank such as Ikesu, ammonia nitrogen compounds are removed.
In addition to nitrate nitrogen compounds, nitrite nitrogen compounds, which are neurotoxic to fish, are also produced, which is undesirable.

However, if aerobic microorganisms are acclimatized and cultured using the above-mentioned method using granulated blast furnace water as a carrier for immobilizing microorganisms, and the obtained microorganisms are used to purify a storage tank for fish, fish, etc. On the other hand, the production of harmful nitrite nitrogen compounds is 0.
The amount of the remaining ammonia nitrogen compound is also less than 0.5 μ/f, and has no adverse effect on the fish being raised.

From these results, we found that when blast furnace granulation is used for the acclimation of microorganisms used in the purification treatment of storage tanks such as Ikesu, and when used as an immobilization carrier in culture, the microorganisms become highly concentrated, and the microorganisms that produce harmful nitrite-nitrogen compounds. It has become clear that an aerobic microorganism suitable for the purification treatment of aquariums for breeding fish, etc., can be obtained with almost no acclimatization or cultivation.

Next, a method for acclimating and cultivating denitrifying bacteria that reduces nitrate nitrogen compounds produced by anaerobic microorganisms, ie, aerobic microorganisms, to nitrogen gas will be explained.

When acclimating and culturing denitrifying bacteria under anaerobic conditions, it is not preferable if anaerobic microorganisms, such as sulfur-reducing bacteria, are acclimated and cultured at the same time in addition to the denitrifying bacteria. In other words, when sulfur-reducing bacteria are present, aerobic microorganisms oxidize sulfide contained in fish excrement, bait residue, etc., reducing the sulfate ions produced and regenerating sulfide before fish respiration. generate. Therefore, it is necessary to suppress as much as possible the acclimatization and cultivation of anaerobic microorganisms such as sulfur-reducing bacteria in addition to denitrifying bacteria.

As a result of intensive research, the inventors have found that managing and controlling the ORP of the reactor will improve the habituation of anaerobic microorganisms such as sulfur-reducing bacteria.
We have established a method that allows denitrifying bacteria to be habituated and cultured in a fairly preferential manner by suppressing culture.

That is, the present inventors found that the denitrification reaction in the reactor was 0.
RP (occurs in the range of 1 to -150 mV (Ag-AgC1 electrode reference), and when the nitrate nitrogen compound in the reactor is reduced to nitrogen gas and almost all nitrate ions disappear, O
We found that RP decreased rapidly and became significantly anaerobic.

From this, we can set the ORP of the reactor to 0~-150mV.
(Ag-AgC1 electrode standard) If managed and controlled within the range of Since we have carried out acclimatization and culture, we will explain the method.

First, the activated sludge collected from the aeration tank of the activated sludge treatment equipment at a municipal sewage treatment plant is mixed into an anaerobic biochemical treatment equipment consisting of an ORP control device, a pH control device, and an agitator, and an actor and a sludge settling tank. 1 to 10% by weight of granulated blast furnace powder (20 to 200 μm) based on the capacity of the reactor is added, and the mixture is stirred to an extent that activated sludge and blast furnace granulated water do not settle. To this reactor, artificial sewage with 50 μ/β (as nitrate nitrogen) added of nitrate nitrogen compounds instead of the ammonia nitrogen compounds in the artificial sewage described above is supplied so that the treatment time is 6 to 8 hours. do. Note that the sludge return rate from the sludge settling tank to the Riactor was approximately 25%.

At this time, the ORP of the reactor is O~-150mV (A
g-AgC1 electrode standard) and ORP is 1.
Automatic on-off control was performed in which aeration was started when the voltage was below 50 mV, and aeration was stopped when the voltage returned to -150 mV. Also,
Since sludge and blast furnace granules settle in the reactor because aeration is rarely performed, in order to prevent this, the artificial sewage containing nitrate nitrogen compounds is treated while stirring the reactor mechanically. Note that the pH of the reactor tends to increase as seawater-resistant denitrifying bacteria become acclimated and cultured, so if the proportion of seawater in artificial sewage is about 50% or less, the pH of the reactor should be around 8.0 to 8.5. When the ratio becomes about 50% or more, the pH of seawater is managed and controlled to be about 7.6 to 8.0. It has been revealed that when the treatment is carried out in this manner, the nitrate ion concentration of the treated water becomes 1 mg/42 or less, and nitrate nitrogen compounds are efficiently reduced and removed.

It should be noted that denitrifying bacteria, like the nitrifying bacteria described above, have a slow growth rate and have poor sedimentation properties, so they easily leak into the treated water, making it difficult to maintain a high concentration of denitrifying bacteria in the reactor. be. For this reason, blast furnace granulation is added to the reactor,
We immobilized denitrifying bacteria in the blast furnace granules to improve sedimentation in the sludge settling tank, suppress the flow of denitrifying bacteria into the treated water, and increase the concentration of denitrifying bacteria in the reactor.

In addition, artificial sewage containing organic substances such as meat extract, peptone, yeast extract, and dextrin (approximately 10 to 50 μ/L as BOD) was used as a hydrogen donor when reducing nitrate nitrogen compounds to nitrogen gas. Organic substances are required, and these organic substances are suitable for culturing and propagating various microorganisms.

Next, the acclimatization of denitrifying bacteria to seawater will be explained.

A method for imparting seawater resistance to denitrifying bacteria is to gradually increase the mixing ratio of seawater in artificial sewage, as in the case of acclimatization of seawater-resistant nitrifying bacteria described above. Specifically, artificial sewage containing nitrate nitrogen compounds (approximately 50 μ/l as nitrate nitrogen) is treated, and the nitrate nitrogen compounds in the treated water are 10 μ/l as nitrate nitrogen. When the ratio is below, the mixing ratio of seawater is increased by about 10%, and finally seawater-resistant denitrifying bacteria that can reduce almost 100% of nitrate nitrogen compounds with 100% seawater can be obtained.

When the denitrifying bacteria obtained in this way is used for the purification treatment of a culture tank such as Ikesu, the seawater of the culture tank such as Ikesu is first cultured and the seawater-resistant nitrifying bacteria whose growth method was explained above are immobilized. This seawater is then passed through a module in which seawater-resistant denitrifying bacteria have been immobilized. At this time, a part of the seawater in the Ikesu culture tank is passed through a module in which seawater-resistant denitrifying bacteria are immobilized. This is because seawater-resistant denitrifying bacteria require organic matter as a hydrogen donor when reducing nitrate nitrogen compounds, so this is due to the fact that the leftovers from feeding, fish excrement, etc. contained in the seawater of the Ikesu culture tank, etc. This is because organic matter is used as a hydrogen donor.

The function of this module is to first oxidize and decompose organic matter such as fish excrement and bait leftovers in a module immobilized with seawater-resistant nitrifying bacteria, and also to oxidize ammonia nitrogen compounds to nitrate nitrogen compounds. .

Next, in a module in which seawater-resistant denitrifying bacteria are immobilized, the seawater-resistant denitrifying bacteria use organic matter contained in the seawater in a storage tank such as Ikesu as a hydrogen donor, converting nitrate nitrogen compounds into nitrogen gas. Reduce and remove.

By treating the seawater in the aquarium for breeding fish, etc., in this way, the seawater can always be maintained in a clean state, and saltwater fish can be raised without replacing the seawater for a long period of time.

(Example) Example 1 An example of a method for acclimatizing and cultivating aerobic microorganisms suitable for purifying a culture tank for saltwater fish, etc., will be described.

A mixed solution of activated sludge (concentration: 1500 ~ 2000■/2), and as organic components, meat extract 5■/ρ and peptone 5mg/
e, yeast extract 6■/I! ,,dextrin 2.4
Artificial sewage in which mg/E and ammonium sulfate (50 μl/poor (as ammonia nitrogen)) were dissolved in fresh water was passed through the aeration tank. In addition, 1% by weight of granulated blast furnace powder (particle size: 20 to 200 μm) was added to the aeration tank as an immobilized carrier for activated sludge for 5 days.

The activated sludge treatment conditions at this time are as follows.

○ pH of the aeration tank; seawater mixing ratio changed by seawater mixing ratio 0-50%; control seawater mixing ratio 50-50% at 7.0-7°5
100%; ORP H of control O aeration tank to 7.5-8.0
200 to 250 m V control (Ag-AgCI electric scraping standard) O sludge return rate: Approximately 25% ○ Processing time: Approximately 6 to 8 hours ○ Aeration amount: Such activated sludge treatment performed using the ORP of the aeration tank as an index When this was carried out, the concentration of ammonia nitrogen in the treated water decreased to less than 0.01 μ/1 and the concentration of nitrate nitrogen decreased to approximately 50 u/1 within 5 days after the addition of granulated blast furnace water was completed. Therefore, if 10% of the fresh water in the artificial sewage mentioned above is replaced with seawater and the same treatment is carried out, the ammonia nitrogen in the treated water will be 0 by the next day.
．． 01■/! Below, nitrate nitrogen is also about 50■/l
Became.

Furthermore, in order to enhance the adaptability of this aerobic microorganism to seawater, the treatment was continued for about 7 to 10 days at the same seawater concentration even after the ammonia nitrogen was sufficiently oxidized.

After that, each time the freshwater in the artificial sewage is replaced with seawater by approximately 10%, this operation is repeated to increase the seawater concentration, gradually increasing the adaptability of aerobic microorganisms to seawater, and finally replacing the entire amount of freshwater in the artificial sewage. Replaced with seawater. The activated sludge (7) MLVSS concentration at this stage is approximately 50
00 to 7,500 mg/1, and can be used for purifying aquariums for breeding fish, etc.

Example 2 An example of a method for acclimating and cultivating aerobic microorganisms suitable for purifying a culture tank for seawater fish such as Ikes will be described.

In an anaerobic reactor (reactor volume 502) equipped with a stirrer, an ORP controller and a pH controller, Example-
Using the same method as in step 1, add a mixed solution of activated sludge collected from the aeration tank of the activated sludge treatment equipment at a sewage treatment plant, and add 5/2 of meat extract as an organic component while stirring the inside of the reactor.
, peptone 5■/yeast extract 6■/l, dextrin 2.4■/I! , and sodium nitrate (50 mg/EC as nitrate nitrogen) were dissolved in fresh water and artificial sewage was passed through the reactor. In addition, granulated blast furnace powder (particle size 20 to 200 μm) was added to this reactor as an immobilization carrier for activated sludge.
was added at a rate of 1% by weight based on the reactor capacity per day for 5 days.

The conditions for the anaerobic treatment at this time are as follows.

○ pH of aeration tank; seawater mixing ratio changed by seawater mixing ratio O ~ 50%; control seawater mixing ratio 50 ~ 8.0 ~ 8.5
100%; Controlled to 7.6-8.0 ○ ORP H of aeration tank
-150 mV control (Ag-AgC1 electrode standard) The ORP of the reactor was controlled using an ON-OFF method in which aeration was performed when the voltage was below 150 mV, and aeration was stopped when the voltage was restored to -150 mV.

O sludge return rate: Approximately 25% ○ Processing time: Approximately 6 to 8 hours When anaerobic activated sludge treatment is carried out in this manner, nitric acid in the treated water is removed within approximately 5 days after the addition of granulated blast furnace water is completed. Seawater nitrogen makes up 10% of the fresh water in artificial sewage at approximately 0.05■/!
Became. Further, in order to enhance the adaptability of the anaerobic microorganisms to seawater, the treatment was continued for about 7 to 10 days at the same seawater concentration even after nitrate nitrogen had been sufficiently reduced.

After that, this operation is repeated every time approximately 10% of the freshwater in the artificial sewage is replaced with seawater to increase the concentration of seawater, gradually increasing the adaptability of anaerobic microorganisms to seawater, and finally the entire amount of freshwater in the artificial sewage is replaced. Once it had been replaced with seawater, it was used to purify fish tanks and other fish tanks.

(Effects of the Invention) As explained above, the method of the present invention has the effect of oxidatively decomposing pollutants in a culture tank such as fish, or reducing nitrate nitrogen compounds to nitrogen gas. In addition, the module for purifying aquariums such as Ikesu for saltwater fish using these microorganisms can be used immediately compared to conventional purification methods, and is also superior in removing pollutants. Therefore, the purification module can be made compact.

Agent Patent attorney Masamitsu Akizawa and one other person voluntary procedure amendment 1. Case display patent application No. 1-89984 Microorganisms suitable for treatment! ! 71111, Cultivation Method 3, Relationship with the amended person case Application Address 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name (665) Nippon Steel Corporation 12 Nihonbashi Kabutocho, Chuo-ku, Tokyo Number 1\.

Claims (2)

[Claims] (1) Put the sewage activated sludge mixture and granulated blast furnace water into an aeration tank for activated sludge treatment equipped with an oxidation-reduction potential (ORP) control device and a pH control device, and use the ORP of the aeration tank as an index to air the While aerating, freshwater artificial sewage containing ammoniacal compounds and organic matter that can be decomposed by activated sludge is supplied to the aeration tank, and when more than 80% of the ammoniacal nitrogen compounds have been oxidized to nitrate nitrogen compounds, The freshwater of the artificial wastewater is successively replaced with seawater, and when finally 90% or more of the ammonia nitrogen compounds in the 100% seawater artificial wastewater are oxidized to nitrate nitrogen compounds, it can be used for the purification of seawater live fish. A method for acclimating and cultivating aerobic microorganisms suitable for purifying a culture tank for seawater live fish such as Ikesu, which is characterized by: (2) Put the activated sludge mixture from the sewage treatment plant and the granulated blast furnace water into an anaerobic reactor equipped with an agitator, an ORP control device, and a pH control device, and decompose it with nitrate nitrogen compounds and activated sludge while stirring the inside of the reactor. Once more than 80% of the nitrate nitrogen compounds have been reduced and removed, the freshwater in the artificial sewage is gradually replaced with seawater, and finally the artificial sewage is made up of 100% seawater. When 90% or more of nitrate nitrogen compounds in sewage have been reduced, it can be used for purification treatment of culture tanks such as Ikesu for seawater live fish.Suitable for purification treatment of culture tanks such as Ikesu for seawater live fish. Acclimatization and culture methods for anaerobic microorganisms.