JPH05285492A - Seawater purifying material and method - Google Patents

Abstract

PURPOSE:To purify the water of a water tank breeding marine fish by circulating seawater and to provide novel marine nitrifying bacteria. CONSTITUTION:A seawater purifying material to be used is obtained by immobilizing marine nitrifying bacteria Nitrosococcussp. DA-001 strain and/or a marine nitrifying bacteria group on a synthetic polymer carrier composed of polyvinyl alcohol or the like. A proper column provided to a drain system is packed with this purifying material and the waste water from a breeding water tank is passed through the packed column to be purified. By this constitution, the grasping of nitrifying bacteria immobilized on the carrier is easy and this purifying material has mechanical strength and can be stored at a low temp. and, therefore it can be used in an arbitrary amount according to the purpose of use.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seawater purification material and a seawater purification method that can be used for the circulation and filtration of marine fish such as marine fish.

[0002]

2. Description of the Related Art Conventionally, freshwater fish such as tropical fish are bred in domestic aquariums, and saltwater fish such as horse mackerel and Thailand are bred in aquariums at restaurants and aquariums. In this case, it is difficult to constantly supply fresh water to the aquarium,
Especially in the case of seawater, it is difficult to replenish it with fresh seawater, so the water is filtered and circulated. In such circulation filtration rearing, it is necessary to purify water pollutants such as excrement and residual food accompanying the metabolism of fish in order to reuse rearing water. Among them, ammonia is excreted in a large amount and is highly toxic to fish. Therefore, when a large amount of fish is bred, it must be rapidly purified and removed. Conventionally,
In most cases, ammonia purification in fish farming
It is carried out by a biofilm method that utilizes the metabolism of purification microorganisms (nitrifying bacteria) attached to the surface of sand, plastic filter media and the like.

[0003]

However, in the conventional purification of breeding water, it is difficult to artificially control the microorganisms because it is purified by naturally occurring microorganisms, it takes time for aging, and the biofilm is peeled off by a physical operation. However, there is a problem that the purification capacity is deteriorated. In the field of wastewater treatment, the activated sludge method is known as a method for treating municipal sewage, factory wastewater, etc., but this method mainly removes organic matter, and it takes a lot of time and a large amount of time to perform solid-liquid separation. Since it requires a device, it has not been applied to the purification of circulating breeding water for aquatic products.

The microorganism immobilization method is to fix and embed microorganisms on the surface or inside of a carrier while maintaining its activity. Useful purified microorganisms can be utilized selectively and at high concentration, so that treatment efficiency can be improved. It is considered to be extremely effective in making facilities compact. The inventors of the present invention thought that improvement of the treatment efficiency and stabilization could be expected by applying the microorganism immobilization method even in the purification of water in circulation filtration breeding, but there have been some examples of application to purification of seawater so far. Absent. It is an object of the present invention to develop an efficient filtration tank using an immobilized microorganism in which a microorganism is carried on a specific immobilization carrier, and to apply it to a marine fish circulation filtration breeding system.

[0005]

[Means for Solving the Problems] As a result of various studies conducted by the present inventors on the purification of circulating breeding water for marine products, it was found that marine nitrifying bacteria were immobilized on synthetic polymers by the microbial immobilization method. The present invention has been completed by finding that it can be used for the purpose.

The group of marine nitrifying bacteria used in the present invention is obtained from a marine product breeding aquarium that has been used for a long period of time, for example, from its filtration tank.
Bacteria isolated by the inventors using Watson's medium are suitable. The separation was carried out by the dilution method after the enrichment culture and the kesmotat culture. The isolated strains are morphologically observed using a phase-contrast microscope and a transmission electron microscope.
As a result of examining the characteristics with respect to H, temperature, etc., the following characteristics are shown. The isolated strain is a gram-negative, motile coccus having a diameter of about 2 μm, and a lamellar membrane organelle is observed in the center of the cell. For salinity, salinity 10
Ammonia oxidation was observed at ~ 35, and the highest rate of ammonia oxidation at salinity 25 showed the characteristics considered to be halophilic bacteria. Based on these characteristics, the isolated strain is N
It is considered to be a strain similar to itrosococcus oceanus, and the strain has the highest ammonia oxidation rate at pH 8 and temperature 30 ° C, and the ammonia oxidation rate decreases otherwise.

The above isolated strain is a new strain not described in the literature.
Itrosococcus sp. DA-001 strain was named
Deposited as No. 2904. Marine nitrifying bacteria Nitrosoco
In addition to the ccus sp. DA-001 strain, it is possible to use a group of marine nitrifying bacteria having the same characteristics as described above, which can be separated by the same separation method as described above. Therefore, the seawater purification material of the present invention is characterized by immobilizing the marine nitrifying bacterium Nitrosococcus sp. DA-001 strain or a group of marine nitrifying bacteria having similar characteristics on a synthetic polymer carrier.

The synthetic polymer used as a carrier in the present invention is not particularly limited as long as it can immobilize marine nitrifying bacteria, but since it is bred by circulating water, it harms organisms such as fish. Those that do not contain such elements and have a certain degree of mechanical strength are preferred. For example, polyvinyl alcohol (PVA), photocurable polyvinyl alcohol (PVA-SbQ) or polyethylene glycol (PVA).
EG) and the like are preferable, and synthetic polymers composed of carbon, hydrogen and oxygen, and those having a hydrophilic group such as a hydroxyl group and a carboxyl group are more preferable. In use, these synthetic polymers may be gelled using an appropriate gelling agent according to a conventional method and molded into a spherical or rectangular shape having an appropriate size before use. For gelling, for example, PVA uses boric acid as a gelling agent. More specifically, PVA having a high degree of polymerization and a high degree of saponification is preferable.
Those having 1500 or more and a saponification degree of 85% or more can be preferably used. Commercially available products include PVA-HC (Kuraray: polymerization degree 2000, saponification degree 99.85%) for PVA.
Examples of A include SPP-H-13 Hosbq-785 (polymerization degree 1700, saponification degree 88%, PVA-SbQ) manufactured by Toyo Gosei Co., Ltd.
The photocurable PVA is gelled with a suitable photocrosslinking agent.
PEG having a molecular weight of about 500,000 is usually used.

As a method for immobilizing microorganisms, a carrier binding method, a cross-linking method and an entrapping method are known, and the entrapping method can be preferably used in the present invention.

The present invention also relates to a method for purifying seawater, characterized in that the above-mentioned seawater purification material is used in a marine product circulation filtration rearing system. The seawater purification material is used by filling it in a purification column or the like provided between the breeding water circulation channel or the seawater intake channel of the marine product circulation filtration breeding system.

As described above, according to the present invention, as a purification material, a synthetic polymer is loaded with a marine nitrifying bacterium Nitrosococcus sp. DA-001 strain or a group of marine nitrifying bacteria showing similar characteristics. Easy to manage. Therefore, even when the capacity of the breeding aquarium is increased or the number of breeding fish is increased, it can be easily dealt with by increasing the usage amount of the purification material of the present invention.

[0012]

[Experimental Example] The present invention will be described below based on an experimental example.
The present invention is not limited to this.

Experimental Example 1 The following experiment was conducted in search of an immobilizing material usable for purifying seawater. Carriers prepared by immobilizing marine nitrifying bacteria using 3 types of natural polymers and 7 types of synthetic polymers as immobilization materials (hereinafter referred to as immobilization carriers) were compared. In addition,
The immobilization material used in the experiment is being studied for application in the field of wastewater treatment.

(1) Materials and Methods Table 1 shows the immobilization materials used in the experiment. The immobilization method is
The procedure was carried out in the usual manner except that seawater was used as the solvent for the immobilization material. All seawater used was natural seawater (salinity 3.4).

[Table 1] Table 1 Immobilized materials tested and its immobilization method ────────────────────────────────── ─── Fixing material Resin concentration (%) Shape ^a) Fixing method ^b) ──────────────────────────────── ───── Natural polymer Agar 3.0 Cylindrical (3 × 3mmφ) After heating and melting, cooling κ-Carrageenan 3.0 Cubic (3 × 3 × 3mm) Same as above Alginic acid 3.0 Spherical (3mmφ) Na alginate Synthetic polymer PVA 10.0 Spherical (3mmφ) PVA-Boric acid method PAA 18.0 Cubic (3 × 3 × 3mm) Acrylamide method PEG 30.0 Cubic (3 × 3 × 3mm) Same as above Photocurable resin PVA-SbQ 9.0 Spherical (3mmφ) Photocurable Resin method ENTG-3800 32.0 Spherical (3 mmφ) Same as above ENT-1000 53.0 Spherical (3 mmφ) Same as above ENTV-500 10.0 Spherical (3 mmφ) Same as above ── ───────────────────────────────── a) If a spherical shape cannot be formed during the fixing operation, the razor after fixing Shred with. b) The immobilization method was a conventional method except that seawater was used as the solvent for the immobilization material.

The marine nitrifying bacteria used for immobilization were obtained by culturing sludge in a filtration tank of a breeding aquarium (total water amount: 0.8 t) of a circulation filtration system. The sludge was collected from the surface of the filter medium in the filtration tank, the number of heterotrophic bacteria was reduced by the dilution method, and the sludge was cultured for about 1 month using a 2 liter (l) volume culture device. For the culture, a medium in which 10 mM ammonium sulfate is added to seawater is used, and the culture conditions are 30 ° C. and pH 7.5 to 8.5. For immobilization, centrifugation was performed (8000 rpm, 4
℃) and concentrated 100 times. Further, the same can be applied to the marine nitrifying bacterium Nitrosococcus sp. DA-001 strain.

The comparison of the immobilized carriers was carried out by culturing with shaking at 30 ° C. for 1 week, using the activity residual rate at the time of immobilization and the mechanical strength as indexes. Seawater containing 10 mM ammonium sulfate and 50 mM HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) was added to the medium.
Using 00 ml (adjusted to pH 8.5 with K ₂ CO ₃ ), shaking was performed with a rotary shaking culture device (100 rpm) manufactured by Taiyo Kogyo Co., Ltd. The residual activity rate was expressed as a ratio by measuring the ammonia oxidation rate of the immobilized carrier and the ammonia oxidation rate of the same amount of nitrifying bacteria culture solution as used for immobilization. The mechanical strength of the immobilized carrier was judged from the visually damaged state of the carrier. The ammonia oxidation rate was 2, 4,
Sampling was performed after 6, 12, and 24 hours, and NH ₄ in the culture solution
-N, NO ₂ -N, and NO ₃ -N concentrations, each indophenol method, GR method, was calculated by measuring for using ion chromatography analyzer (IC-500, manufactured by Yokogawa).

(2) Results The results are shown in Table 2. Natural polymer has a residual activity rate of 50-65
%, But the mechanical strength of the immobilized carrier was so small that it collapsed within 2 days of shaking culture. On the other hand, the synthetic polymer did not disintegrate after 1 week of shaking culture, but the residual activity rates of polyvinyl alcohol (PVA), photocurable resin (PVA-SbQ), and polyethylene glycol (PEG) were 32 and
40% and 22%, which are slightly lower than natural polymers, polyacrylamide (PAA), commercially available photocurable resin for immobilization (ENTG-3
800, ENT-1000, ENTV-500) could not detect any activity after immobilization. The photocurable resin for immobilization is mainly composed of polyethylene glycols (PEG), polypropylene glycols (PPG) and polyvinyl alcohol (PVA) as a skeleton, and has photocurable ethylenically unsaturated groups at both ends and in the molecular chain. ENTG-3800 is a combination of PEG and PPG, EN
The T-1000 is a PEG type and the ENTV-500 is a PVA type. Based on the above results, it was concluded that among the immobilization materials, PVA, a photopolymerizable resin (PVA-SbQ), which is a synthetic polymer, and PEG can be used to purify seawater.

[0018]

[Table 2] Table 2 Results of examination on active residual rate and mechanical strength of immobilization materials ────────────────────────────── ────── Immobilization material Active residual rate ^a) Mechanical strength ^b) ──────────────────────────────── ───── Natural polymer agar 49.7 2 κ-carrageenan 64.6 2 Alginic acid 63.5 2 Synthetic polymer PVA 31.8 7 <PAA ND ^c) 7 <PEG 22.3 7 <Photo-curable resin PVA-SbQ 40.1 7 <ENTG-3800 ND 7 <ENT-1000 ND 7 <ENTV-500 ND 7 <Control area (floating sludge) 100.0 ────────────────────────────── ─────── The experiment was carried out by shaking culture under conditions of temperature 20 ° C. and pH 8.5. a) Activity residual rate (%) = Ammonia oxidation rate of immobilized nitrifying bacteria / Ammonia oxidation rate of non-immobilized nitrifying bacteria x 100 b) Number of days required for gel disintegration under rotary shaking culture at 30 ° C and 100 rpm. c) Undetectable Further, in this experimental example, the effectiveness was determined by using the mechanical strength and the residual activity ratio of the immobilized carrier as indexes, but the simplicity of the immobilization operation and the cost required for immobilization are also important indexes. Conceivable. The above three usable immobilization materials are PVA
However, the immobilization procedure is the simplest, and the immobilization resin and reagents are inexpensive.

Experimental Example 2 In order to examine the effectiveness of the microorganism immobilization method for improving the treatment efficiency, a reactor filled with an immobilization carrier was used to continuously treat the artificial wastewater with an ammonia oxidation rate of the immobilization carrier. It was measured by

(1) Materials and Methods For the experiment, the fluidized bed reactor with air lift shown in FIG. 1 was used. The reactor 2 filled with the immobilized carrier 1 was made of glass and had a volume of 60 ml. The artificial drainage was set by a peristaltic pump (circulation pump) 5 from the lower part of the reactor 2 through a drainage pipe 7 made of silicon tube, and discharged from the side of the reactor 2 as treated water through a water supply pipe 6 to a breeding tank or the like. .. Further, the water 3 in the reactor was stirred and air was supplied by an air lift system in which the air from the air pump 4 was sent to the reactor 2 through the intake pipe 8. The air flow rate at this time was 1 l / min. The experiment was conducted in a dark room.

Acclimation of PVA-immobilized carrier The PVA-immobilized carrier was prepared by the PVA-boric acid method. The prepared immobilized carrier was acclimated for 150 days in a 500 ml Erlenmeyer flask before being transferred to the reactor. The acclimatization condition is as a medium
Seawater containing 10 mM ammonium sulfate and 50 mM HEPES (K ₂ CO _2
The pH was adjusted to 8.5 using ₃ ) 200 ml was used, and the rotary shaking culture was performed at 30 ° C. and 100 rpm. The medium was exchanged at intervals of 2 to 3 days, and the ammonia oxidation rate was measured at the time of medium exchange in order to observe the aging state.

Ammonia oxidation rate of PVA-immobilized carrier Experimental conditions are shown in Table 3.

[Table 3] Table 3 Experimental conditions for measuring ammonia oxidation rate ──────────────────────────────────── Artificial Wastewater ^a) Immobilization carrier filling rate ^b) Experimental section ─────────────────── (%) Ammonia concentration (mg-N / l) Flow rate (ml / h) ─ ─────────────────────────────────── 1 10 120 10, 20, 30, 40 ────── ─────────────────────────────── 2 100 120 10, 20, 30, 40 ────────── ─────────────────────────── 3 10 120, 240, 380, 450 40 ────────────── ─────────────────────── Experiment: temperature 20 ℃, pH 7.5, aeration 1l / min
It was carried out by continuously treating the wastewater under the conditions of. a) (NH ₄ ) ₂ SO as ammonia in natural seawater (salt content 3.4)
₄ was added. b) The packing rate is shown by the volume ratio of the immobilized carrier to the reactor volume of 60 ml.

The experiment was carried out at a temperature of 20 ° C., a pH of 7.5, and an air flow rate of 1
Under the conditions of l / min and artificial drainage flow rate of 120 ml / h, in Experiment Zone 1, seawater with an ammonia concentration of 10 mg-N / l was used as artificial drainage.
In Experiment Group 2, seawater with an ammonia concentration of 100 mg-N / l was used. Immobilized carrier filling rate per reactor volume is 10,
The rate of ammonia oxidation per reactor and the rate of ammonia oxidation per immobilized carrier were determined at 20, 30, and 40%. In addition, as the experimental section 3, the artificial wastewater having an ammonia concentration of 10 mg-N / l was changed to a flow rate of 120 to 450 ml / h, and the ammonia oxidation rate of the immobilized carrier under conditions where ammonia was sufficiently present was obtained. The filling rate of the immobilized carrier at this time was 40%. The rate of ammonia oxidation was sampled ₂ , ₄ , 6, 12, and 24 hours after the start of the experiment, and NH ₄ -N, NO ₂ -N, N in the treated water were sampled.
It was calculated from the O ₃ -N concentration.

(2) Results Aging of PVA-immobilized carrier The change in the ammonia oxidation rate of the PVA-immobilized carrier is shown in FIG. The ammonia oxidation rate of the immobilized carrier gradually increased immediately after the start of the culture, and on the 14th day, the activity was about 4 times as high as that immediately after the start of the culture. After that, it was kept almost constant, and after 150 days, the activity was constant. Further, the ammonia oxidation rate which became constant was higher than the ammonia oxidation rate corresponding to 100% of the active residual rate at the time of immobilization. From the above results, it was found that under the conditions of this example, at least 14 days or more of culturing was required for ripening, but the aging could sufficiently recover the activity decrease at the time of immobilization. Regarding the growth of microorganisms in the immobilization carrier, it is considered that marine nitrifying bacteria grew inside the immobilization carrier due to the improvement of the ammonia oxidation rate of the immobilization carrier.

Ammonia Oxidation Rate of PVA-Immobilized Carrier The results of Experimental Group 1 are shown in FIG. The ammonia oxidation rate of the immobilization carrier increased with the increase of the immobilization carrier loading rate per reactor, and up to 95% of the ammonia in the artificial wastewater was oxidized at the loading rate of 40%. However, there was a tendency for the amount of immobilized carrier to decrease as the filling rate increased. The result of the experimental section 2 is shown in FIG. The ammonia oxidation rate of the immobilization carrier increased almost linearly with the increase of the immobilization carrier filling rate per reactor, and the ammonia removal rate was as low as 27% at the filling rate of 40%, but it was 1 day per 60 ml reactor volume. It was found to have the ability to oxidize 79.0 mg-N of ammonia. However, the ammonia oxidation rate per immobilized carrier tended to decrease as the filling rate increased, as in the case of Experiment Group 1. The results in Experimental Section 3 are shown in FIG. The rate of ammonia oxidation per reactor of immobilized carrier increases with the increase of flow rate, and the flow rate is 360 ml / h.
From the above, it was found that there is an ability to oxidize 71.3 mg-N ammonia per 60 ml reactor volume per day. However, the ammonia removal rate decreased as the flow rate of artificial wastewater increased.

[0026] There are already published reports for ammonia oxidation rate of the biological membrane method, 150 to 1 day in the plastic filter medium 1m ³
It is stated that it can oxidize 200 g-N of ammonia. The immobilization carrier used this time, when treating artificial wastewater with an ammonia concentration of 10 mg-N / l, a maximum of 1.2 kg-N ammonia per day in a reactor volume of 1 m ³ with an immobilization carrier filling rate of 40%. Since even 10% has the ability to oxidize 250 g-N of ammonia, it was found that the rate of ammonia oxidation of the immobilized carrier was much higher than that of the biofilm under different experimental conditions. Therefore, it seems that the microorganism immobilization method is effective in improving the treatment efficiency. In addition, under conditions where there is sufficient ammonia, the ammonia oxidation rate per reactor is improved in proportion to the packing rate of the immobilization carrier, so the total amount of immobilization carrier can be adjusted to purify the entire filtration tank. It seems that the ability can be controlled.

Experimental Example 3 In this example, for the purpose of clarifying the environmental characteristics of the immobilized carrier, an attempt was made to compare the ammonia oxidation rate when the temperature, pH, etc. were changed with that of a biofilm.

(1) Materials and Method In the experiment, the fluidized bed reactor by the air lift shown in FIG. 1 and having a capacity of 110 ml was used. As the immobilization carrier, one prepared by the PVA-boric acid method was used. The filling rate per reactor volume was 20%. Biofilm length 15
A cm-shaped fibrous filter medium was used. Both the immobilized carrier and the biofilm were placed in a 2 liter fermentor before being transferred to the reactor.
It was cultivated for a month and acclimated. The acclimatization condition is 10
Using seawater supplemented with mM ammonium sulfate, temperature 30 ℃,
pH is 7.5. The experimental conditions are shown in Table 4.

[0029]

[Table 4] Table 4 Experimental conditions relating to ammonia oxidation rate and environmental factors ──────────────────────────────────── ─ Experiment temperature pH ^a) DO ^b) Salinity ^c) Ammonia stirring time ^e) Organic matter load ^f) Group (℃) (%) Concentration ^d) (min) (Treatment days) (mg-N / l) ───── ─────────────────────────────── 1 10-45 7.5 100 100 100 − − ────────── ─────────────────────────── 2 20 4.0-9.0 100 100 100 − − ───────────── ─────────────────────── 3 20 7.5 0-100 100 100 − − ───────────────── ─────────────────── 4 20 7.5 100 0-100 100 − − ────────────────────── ─ ────────────── 5 20 7.5 100 100 10-2000 − − ────────────────────────── ────────── 6 20 7.5 100 100 100 0-120 − ─────────────────────────────── ────── 7 20 7.5 100 100 100 − 0-60 ─────────────────────────────────── ── The artificial drainage flow is 220ml / h in Experiment Zones 1 to 6, and in Experiment Zone 7
Then, it was set to 110 ml / h. a) The pH was adjusted using HCl and K ₂ CO ₃ . b) DO was prepared by mixing N ₂ gas in aeration 1 l / min. c) The salt content was prepared by diluting natural seawater (salt content 3.4) with distilled water. d) Loaded as (NH ₄ ) ₂ SO ₄ . e) Rotational shaking (100 rpm) in 200 ml seawater. f) Loading as meat extract, concentration 50 mg / l (manufactured by Kyokuto Pharmaceutical Co., Ltd.).

The environmental characteristics were compared by measuring the ammonia oxidation rates of the immobilized carrier and the biofilm in each experimental section in duplicate. Regarding the effects of temperature, pH, dissolved oxygen (DO), salinity, and ammonia concentration, the acclimation condition was changed to each environmental condition, and the ammonia oxidation rate was obtained. Sampling of the treated water was performed 1, 1.5 and 2 hours after the start of the experiment. The temperature depends on the constant temperature bath, the pH is 1N HCl or 0.5MK ₂ C
Adjusted with O ₃ . DO was adjusted by the mixing ratio of air and nitrogen gas. Salt is seawater used for artificial drainage (salt
The ammonia concentration was adjusted by diluting 3.4) with distilled water according to the amount of ammonium sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) added to the artificial wastewater. The flow rate of artificial drainage was 220 ml / h. Regarding the effect of agitation, remove the immobilized carrier and the filter material of the biofilm from the reactor and in 200 ml of seawater for 5 minutes ~
After rotating and shaking (100 rpm) for 2 hours, the rate of ammonia oxidation was measured after returning to the reactor for 2 hours. The flow rate of artificial drainage was 220 ml / h. Regarding the effect of organic matter load, artificial wastewater containing 100 mg-N / l ammonia and 50 mg / l concentration meat extract (manufactured by Kyokuto Pharmaceutical Co., Ltd.) was added at a flow rate of 110 ml / h.
And the rate of ammonia oxidation was measured over 60 days. Experimental conditions are temperature 20 ℃, pH 7.5, DO 100%, salinity
3.4. The ammonia oxidation rate was measured for the treated water up to 2 hours later. The results are temperature, pH, DO,
Regarding salinity and ammonia concentration, the rate of ammonia oxidation under acclimatization conditions was defined as 100%, and the specific activity was expressed. For stirring and organic substances, the ammonia oxidation rate at the start of the experiment was set to 100%, and the specific activity was expressed.

(2) Results The ammonia oxidation rates of immobilized nitrifying bacteria and biofilms were 30 to 35 ° C at temperature, 100% at DO, 10 to 34 at salinity, and maximum activity at ammonia concentration of 50 to 200 mg-N / l. , Which is almost in agreement with the characteristics of non-immobilized free marine nitrifying bacteria according to known literature. Regarding the relationship between the stirring time and the ammonia oxidation rate, in the biofilm, the ammonia oxidation rate was reduced to less than half by just 1 hour of rotary shaking, whereas the biofilm could be visually confirmed to be peeled off. , The immobilized carrier was not affected by stirring at all. Regarding the effect of aeration on marine nitrifying bacteria, it has been reported that the nitrifying bacteria free of aeration reduce the ammonia oxidation rate when aerated. On the other hand, it has been found that the immobilized carrier is stable against physical operations such as stirring and can sufficiently perform aeration for supplying oxygen. This is a great advantage when the ammonia oxidation capacity of the filtration tank becomes high and the supply of oxygen by aeration becomes important. Regarding the effect of the addition of organic substances on the ammonia oxidation rate, the ammonia oxidation rate of the immobilization carrier was improved immediately after the start of the experiment, but it stabilized at the 34th day, and both the immobilization carrier and the biofilm's ammonia oxidation rate were tested. It was maintained for 60 days without lowering from the beginning, and neither was significantly affected.

[0032]

INDUSTRIAL APPLICABILITY By immobilizing the marine nitrifying bacterium Nitrosococcus sp. DA-001 strain and / or the marine nitrifying bacterium group with a specific synthetic polymer, the mechanical strength of the present invention is higher than that of conventional biofilms. It is possible to easily obtain a seawater purification material that is large and has a high ammonia oxidation rate. Since the purification material of the present invention has high mechanical strength, it can be mechanically agitated in a breeding aquarium or aerated.
Further, since the marine nitrifying bacterium Nitrosococcus sp. DA-001 strain and / or the marine nitrifying bacterium group is retained in a gel of a synthetic polymer having sufficient water retention property, it can be easily stored, matured and handled. Yes, and because the purification activity per unit amount, for example, per bead, can be easily determined, it can be easily increased in response to an increase in the number of breeding fish or changes in the breeding water volume, and no aging of the immobilization carrier is required. Since it retains approximately 85% activity after 4 days in ammonia-free seawater at 4 ℃, it has many advantages such as being stored in a refrigerator (eg 4 ℃) when not in use. Have.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an experimental device,

FIG. 2 is a graph showing the aging effect of a PVA-immobilized carrier,

FIG. 3 is a graph showing the ammonia oxidation rate of the immobilization carrier in Experimental Zone 1 of Experimental Example 2,

FIG. 4 is a graph showing the ammonia oxidation rate of the immobilization carrier in Experimental Section 2 of the above.

FIG. 5 is a graph showing the ammonia oxidation rate of the immobilization carrier in Experimental Section 3 of the above.

[Explanation of sign]

 1 Immobilized carrier 2 Reactor 3 Seawater 4 Air pump 5 Circulation pump 6 Treated water pipe 7 Drain pipe 8 Air supply pipe

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display area C02F 3/10 A

Claims (6)

[Claims] 1. A marine nitrifying bacterium Nitro is used as a synthetic polymer carrier.
A seawater purification material characterized by immobilizing sococcus sp. DA-001 strain and / or a group of marine nitrifying bacteria. 2. The synthetic polymer is polyvinyl alcohol, photo-curable polyvinyl alcohol (PVA-SbQ) or polyethylene glycol, and marine nitrifying bacteria are immobilized by the microorganism entrapping immobilization method. The seawater purification material described in 1. 3. A marine nitrifying bacterium Nitro is used as a synthetic polymer carrier.
A method for purifying seawater, which comprises using a seawater purification material on which a sococcus sp. DA-001 strain and / or a group of marine nitrifying bacteria are immobilized in a marine product circulation filtration rearing system. 4. The seawater purifying method according to claim 3, wherein the seawater purifying material is used by being filled in a purifying column or the like provided between the seawater circulation channel or the seawater intake channel of the marine product circulation filtration breeding system. Method. 5. A gram-negative, motile coccus having a diameter of about 2 μm, which is separated from a marine product-raising aquarium, and a lamella-like membrane organelle is observed in the center of the cell. Ammonia oxidation was observed at 35, salinity 25
A marine nitrifying bacterium that has the highest ammonia oxidation rate at, pH at 8 and temperature at 30 ° C has the highest rate of ammonia oxidation, and the rate of ammonia oxidation decreases at other times. 6. The marine nitrifying bacterium according to claim 5, which is a Nitrosococcus sp. DA-001 strain (Ministry of Industrial Science and Technology No. 12904).