JP5935076B2 - Water treatment equipment - Google Patents

Description

  The present invention relates to a water treatment apparatus.

  When rearing organisms (for example, fish, shellfish, crustaceans, amphibians, etc.) in a breeding aquarium, the water quality is reduced by suspended suspended matter (SS), ammonia nitrogen, etc. It is necessary to perform water treatment by an appropriate method so as not to deteriorate. In addition, when the concentration of nitric acid in the breeding water increases, it is necessary to drain part of the breeding water and replenish fresh breeding water to dilute the nitric acid concentration.

  Patent Document 1 discloses a closed-circulation type water treatment apparatus that can reduce or eliminate the amount of breeding water supplied. The water treatment apparatus of Patent Document 1 is provided with a nitrification tank and a denitrification tank in parallel, and oxidizes ammonia nitrogen and nitrite nitrogen to nitrate nitrogen by the action of nitrifying bacteria (autotrophic bacteria) in the nitrification tank ( In addition to nitrification, nitrite nitrogen and nitrate nitrogen are reduced to nitrogen (denitrification) by the action of denitrifying bacteria (heterotrophic bacteria) in the denitrification tank.

JP 2011-177619 A

  When a nitrification tank and a denitrification tank are installed in parallel, denitrification in the denitrification tank becomes incomplete due to an unexpected failure, and nitrite nitrogen or ammonia nitrogen is generated in the denitrification tank. Nitrite nitrogen and ammonia nitrogen may flow into the rearing tank. In addition, because the atmosphere in the denitrification tank is anaerobic, the dissolved oxygen concentration of the water to be treated that has passed through the denitrification tank decreases, so when the nitrification tank and the denitrification tank are installed in parallel, the dissolved oxygen concentration Water may flow into the rearing tank.

  From this point of view, the present invention can reduce the risk of these flowing into the breeding tank even if nitrite nitrogen or ammonia nitrogen is generated in the denitrification tank due to an unexpected failure, and It is an object of the present invention to provide a water treatment device that can reduce the risk of water having a low dissolved oxygen concentration flowing into a breeding aquarium.

The present invention that solves the above problems includes a circulation channel that starts from a breeding aquarium and returns to the breeding aquarium, a nitrification unit that is provided in the middle of the circulation channel and that performs nitrification with nitrifying bacteria , and an upstream side of the nitrification unit And a denitrification means that is provided in the denitrification flow path and is denitrified by a denitrifying bacterium , wherein the denitrification means is the nitrification unit Supply of breeding water in the breeding tank through or without means, the nitrification means received supply of breeding water subjected to denitrification treatment by the denitrification bacteria, and nitrification treatment by the nitrification bacteria was made The breeding water is circulated to the breeding tank.

  In short, the present invention uses breeding water containing nitrogen compounds (proteins, amino acids, lipids, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, etc.) using nitrification by nitrifying bacteria and denitrification by denitrifying bacteria. It is to purify, and the breeding water that has passed through the denitrification means is supplied to the nitrification means.

  Nitrifying bacteria are a group of microorganisms involved in oxidizing ammonia nitrogen to nitrate nitrogen (for example, ammonia oxidizing bacteria that oxidize ammonia nitrogen to produce nitrite nitrogen, oxidize nitrite nitrogen) Nitrite-oxidizing bacteria that produce nitrate nitrogen. Most of the nitrifying bacteria belong to chemosynthesis autotrophic bacteria that actively activate and proliferate under aerobic conditions.

  Denitrifying bacteria are a group of microorganisms involved in reducing nitrate nitrogen or nitrite nitrogen to nitrogen (for example, nitrate-reducing bacteria that produce nitrogen by reducing nitrate nitrogen or nitrite nitrogen, sulfur oxidative desorption). It is a general term for nitrifying bacteria. Many of the denitrifying bacteria belong to facultative anaerobic heterotrophic bacteria that can act and grow under anaerobic conditions. In the present invention, sulfate-reducing bacteria that coexist with sulfur-oxidizing denitrifying bacteria are also included in the denitrifying bacteria. Sulfate-reducing bacteria produce sulfate ions and thiosulfate ions by reducing sulfates. Sulfur ions and thiosulfate ions are used for denitrification by sulfur oxidizing denitrifying bacteria.

  According to the present invention, even if nitrite nitrogen or ammonia nitrogen is generated in the denitrification means, it is nitrified in the nitrification means, so that the risk of nitrite nitrogen or ammonia nitrogen flowing into the breeding aquarium Can be lowered. In addition, since nitrification by nitrifying bacteria is performed under aerobic conditions, even if the dissolved oxygen concentration decreases in the denitrification means, it can be recovered, and therefore water with a low dissolved oxygen concentration is returned to the breeding tank. The risk of inflow can be reduced.

In the invention according to claim 1, the flow path for denitrification extends from the breeding water tank to the upstream side of the nitrification means, and the denitrification means supplies the breeding water in the breeding water tank without passing through the nitrification means. The nitrification means is supplied with the breeding water in the breeding aquarium, and is fed with the breeding water that has been denitrified by the denitrifying bacteria, and all the breeding water that has been nitrified by the nitrifying bacteria is that flow ring to the water tank.
Further, in the invention according to claim 2, the denitrification flow path extends from the downstream side of the nitrification means to the upstream side of the nitrification means, and the denitrification means is reared by nitrification treatment with nitrifying bacteria. The nitrification means receives the supply of breeding water in the breeding aquarium, receives the breeding water that has been denitrified by denitrifying bacteria, and part of the breeding water that has been nitrified by the nitrifying bacteria There is supplied to the denitrification unit, that balance flow ring to the breeding tank. That is, in the present invention, the nitrification means is provided in the middle of the circulation flow path for circulating the breeding water in the breeding water tank, and the denitrification means is provided in a flow path different from the circulation flow path. If it does in this way, purification of breeding water by nitrification means can be continued even during maintenance of denitrification means.

  According to the present invention, even if nitrite nitrogen or ammonia nitrogen is generated in the denitrification tank due to an unexpected failure, the risk of these flowing into the breeding tank can be reduced, and the dissolved oxygen concentration The risk of low water flowing into the breeding tank can be reduced.

It is a circulation filtration system diagram for demonstrating the water treatment apparatus which concerns on embodiment of this invention. It is a circulation filtration system diagram for demonstrating the modification of the water treatment apparatus which concerns on embodiment of this invention.

The water treatment apparatus A according to the embodiment of the present invention contains nitrogen compounds (such as suspended suspended matter (SS) derived from excrement and residual food of domesticated organisms, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen). The breeding water W ₀ in the breeding water tank T is purified using nitrification by nitrifying bacteria and denitrification by denitrifying bacteria. As shown in FIG. 1, nitrification means 1 and backwash water supply Means 2, decomposition means 3, denitrification means 4, physical filtration means 5, water temperature adjustment means 6, sterilization means 7, oxygen supply means 8, circulation means (flow paths 91 to 96, pumps 97 to 99), monitoring means for monitoring the concentration of nitric acid breeding water W ₀ in real time (which includes the not shown) and. In the present embodiment illustrates a case where the rearing aquarium T of closed circuit to breeding water W ₀ seawater applying the water treatment apparatus A.

Nitrification unit 1, fed with supplied with breeding water W ₀ of the water tank T, supplied with breeding water W ₄ which has passed through the denitrification device 4 _{(denitrificans} breeding water W ₄ denitrification process has been performed _by) The ammonia nitrogen contained in the breeding waters W ₀ and W ₄ is oxidized (nitrified) to nitrate nitrogen. In the nitrification means 1 of the present embodiment, physical filtration of suspended suspended matter (SS) derived from the excrement and residual food of the rearing organisms is also performed. The nitrification means 1 is provided in the middle of the circulation channel 91 starting from the breeding water tank T and returning to the breeding water tank T. The breeding water W ₁ that has passed through the nitrification means 1 is supplied to the water temperature adjustment means 6, passes through the sterilization means 7 and the oxygen supply means 8, and then circulates to the breeding water tank T. The nitrification means 1 of the present embodiment includes a nitrification tank 11, a nitrifying bacteria carrier 12, an inlet valve 13, and an outlet valve 14.

Nitrification tank 11 is a container sealed to accept breeding water W ₄ which has passed through the portion and denitrification unit 4 of breeding water W ₀ which is water intake from the breeding aquarium T. In the present embodiment, an inlet is provided above the nitrifying bacteria carrier 12 and an outlet is provided below the nitrifying bacteria carrier 12 so that the water flow in the nitrification tank 11 faces downward. In addition, although illustration is abbreviate | omitted, an inflow port may be provided under the nitrifying bacteria support | carrier 12 and an outflow port may be provided above so that the water flow in the nitrification tank 11 may become upward.

  The nitrifying bacteria carrier 12 carries nitrifying bacteria (such as ammonia oxidizing bacteria and nitrite oxidizing bacteria), and is filled in the nitrifying tank 11. The nitrifying carrier 12 functions as a biological filtration means that oxidizes ammonia nitrogen to nitrate nitrogen by the nitrifying action of the nitrifying bacteria fixed therein. That is, nitrite nitrogen is generated by the action of ammonia oxidizing bacteria that oxidize ammonia nitrogen, and nitrate nitrogen is generated by the action of nitrite oxidizing bacteria that oxidize nitrite nitrogen. Since most nitrifying bacteria belong to chemically synthesized autotrophic bacteria that actively activate and proliferate under aerobic conditions, it is desirable to maintain the inside of the nitrifying bacteria carrier 12 in an aerobic atmosphere.

Nitrifying bacteria carrier 12 of the present embodiment is made of a collection of small filtration sand uniformity coefficient, physically capturing stray suspended matter in breeding water W ₀ (SS). Although there is no restriction | limiting in the material of filtration sand, It is preferable to set it as inorganic materials, such as a natural stone and glass. Note that, for example, a down-flow hanging sponge (DHS) may be used in place of the filter sand.

The inlet valve 13 adjusts the amount of breeding water W ₀ and W ₄ flowing from the circulation channel 91 into the nitrification tank 11, and the outlet valve 14 is the breeding water flowing out from the nitrification tank 11 to the circulation channel 91. it is intended to adjust the amount of water in the W _1. The inlet valve 13 and the outlet valve 14 are opened when biological filtration is performed (hereinafter referred to as “normal time”), and are closed during backwashing.

The backwash water supply means 2 supplies backwashing water (backwash water) W ₂ to the nitrifying bacteria carrier 12, and includes a tank (water source) 21, a pump 22, and an on-off valve 23. It is configured.

The tank 21 stores backwash water. The tank 21 of the present embodiment stores treated water (bred water W ₈ that has passed through the aeration means ₈ ).

The pump 22 sends backwash water in the tank 21 to the nitrification tank 11. The on-off valve 23 opens and closes the flow path 94 from the tank 21 to the nitrification means 1 and opens during backwashing and normally closes. Incidentally, the flow path 94, so that the flow direction of the backwash water in nitrifying bacteria carrier 12 is reversed and the flow of the rearing water W _1, leads to the lower side of nitrifying bacteria carrier 12.

The backwash water supply means 2 is operated with the inlet valve 13 and the outlet valve 14 of the nitrification means 1 closed. Operating the backwash water supply means 2, nitrifying bacteria carrier 12 is backwashed by backwash water W _2, backwash water W ₂ which has passed through the nitrification unit 1 _'is adhered to the nitrifying bacteria carrier 12 organics At the same time, it is supplied to the disassembling means 3. That is, when the backwash water supply means 2 is operated, the organic matter attached to the nitrifying bacteria carrier 12 can be recovered.

The decomposition means 3 solubilizes organic substances contained in the backwash water W ₂ ′, and is interposed between the nitrification means 1 and the denitrification means 4. The backwashing water W ₂ ′ that has passed through the nitrifying bacteria carrier 12 is supplied to the decomposition means 3, and the backwashing water W _{3 that} has passed through the decomposition means 3 is supplied to the denitrification means 4. The decomposition means 3 of the present embodiment includes a decomposition tank 31, an inlet valve 32, and an outlet valve 33. The concentration of the solubilized organic substance is continuously monitored with an absorptiometer or the like.

  In the decomposition tank 31, the organic matter is solubilized by the action of the solubilizing bacteria. The solubilization means is not limited, and the organic substance may be solubilized with acid, alkali, enzyme, heat, ozone, ultraviolet light, photocatalyst, microorganism, or the like.

  The inlet valve 32 opens and closes the flow path 95 from the nitrification means 1 to the decomposition tank 31 and opens during backwashing and closes during normal operation.

  The outlet valve 33 opens and closes the flow path 96 from the decomposition tank 31 to the denitrification flow path 92, and opens when supplying the organic matter in the decomposition tank 31 to the denitrification means 4, and otherwise Close the valve.

  It is desirable to adjust the salt concentration in the decomposition tank 31 to 1 to 2%. When solubilized under the condition of a salt concentration of 1 to 2%, the production of ammonia is suppressed, so that the carbon component can contribute as an organic substance necessary for denitrifying bacteria. In addition, when an organic substance is solubilized under the condition of a salt concentration of 3%, the production ratio of ammonia is increased (COD / N = 7.3), so that there is a possibility that a carbon component is used to assimilate ammonia. .

The denitrification means 4 is directly supplied with the breeding water W ₀ in the breeding tank T without passing through the nitrification means 1, and reduces nitrate nitrogen and nitrite nitrogen contained in the breeding water W ₀ to nitrogen. (Denitrification). The denitrification means 4 is provided in a denitrification channel 92 different from the circulation channel 91. The denitrification flow path 92 is a flow path from the breeding water tank T to the circulation flow path 91 on the upstream side of the nitrification tank 11, and downstream of the branch point between the circulation flow path 91 and the physical filtration flow path 93. It joins the circulation channel 91. That is, the entire amount of the breeding water W _{4 that} has passed through the denitrification means 4 is supplied to the nitrification means 1.

  The denitrification means 4 of this embodiment comprises a plurality of denitrification tanks 41, 41,... Provided in parallel and denitrifying bacteria carriers 42, 42,.

The denitrification tank 41 is a sealed container that receives the breeding water W ₀ taken from the breeding water tank T. If the oxidation-reduction potential (ORP) of the denitrification tank 41 is too low, hydrogen sulfide may be generated. Therefore, the oxidation-reduction potential is preferably adjusted to a range of −300 (mV) to −100 (mV). . In order to adjust the oxidation-reduction potential, the amount of breeding water supplied to the denitrification tank 41 and the amount of carbon source / electron donor supplied may be controlled. Moreover, hydraulic retention time in the denitrification tank 41 (HRT) may be set as appropriate depending on the concentration of nitrate nitrogen and nitrite nitrogen contained in the rearing water W ₀ in the breeding aquarium T.

The denitrifying carrier 42 carries denitrifying bacteria (nitrate-reducing bacteria, sulfur-oxidizing denitrifying bacteria, sulfate-reducing bacteria, etc.), and is filled in the denitrifying tank 41. The denitrifying carrier 42 of the present embodiment functions as a biological filtration means for reducing nitrate nitrogen or nitrite nitrogen to nitrogen by the denitrifying action of the denitrifying bacteria fixed inside. Since most of the denitrifying bacteria belong to facultative anaerobic heterotrophic bacteria that can act and grow under anaerobic conditions, it is desirable to maintain the inside of the denitrifying carrier 42 in an anaerobic atmosphere. Since the breeding water W ₀ having a high dissolved oxygen concentration flows into the denitrification means 4, an aerobic atmosphere is formed upstream of the denitrification carrier 42, but oxygen is consumed by bacteria in the denitrification carrier 42, Since it becomes anaerobic as it goes downstream, the denitrification action is maintained.

  The denitrifying carrier 42 is granulated granular sludge. If granulated granule sludge is used, high-efficiency processing becomes possible and the denitrification tank 41 can be made compact, so that the cost can be reduced. In addition, as the denitrifying carrier 42, porous materials such as porous glass, porous ceramic, coral sand, sponge made of natural resin or synthetic resin, activated carbon, and nonporous material such as natural rock or glass are used. Can be used.

The denitrifying carrier 42 is supplied with the organic material solubilized by the decomposition means 3. The organic matter supplied to the denitrifying bacteria carrier 42 is used as a carbon source and electron donor for the denitrifying bacteria. The solubilized organic substance (carbon source) is preferably added so that the carbon ratio (C / N ratio) in the denitrifying carrier 42 is 1.00 to 3.00. In addition, when the amount of organic matter supplied from the decomposition means 3 is insufficient, sodium acetate, acetic acid, methanol, glucose, or the like that serves as a carbon source / electron donor for denitrifying bacteria may be supplied. As the source / electron donor, sodium acetate or acetic acid that does not adversely affect the rearing organism is preferable. The supply amount of the carbon source, the electron donor is adjusted according to the concentration of nitric acid breeding water W _0.

The breeding water W ₀ supplied to the denitrification means 4 is the total amount of breeding water W ₀ supplied to the nitrification means 1, the denitrification means 4 and the physical filtration means 5 (that is, the breeding water taken from the breeding aquarium T). 1 to 20% of the amount of water). By the way, if the breeding water W ₀ supplied to the denitrification means 4 is less than 1% of the amount of breeding water taken from the breeding aquarium T, the possibility that the denitrification process cannot catch up increases and exceeds 20%. In addition, the hydraulic residence time (HRT) in the denitrification means 4 is shortened and the possibility that the denitrification treatment is not sufficiently performed increases, and the possibility that the apparatus becomes excessive increases. However, this value varies depending on which level the quality of the breeding water W ₀ is maintained. In order to make the amount of the breeding water W ₀ supplied to the denitrification means 4 smaller than the breeding water W ₀ supplied to the nitrification means 1, for example, the discharge amount of the pump 99 of the denitrification flow path 92. May be made smaller than the discharge amount of the pump 97 in the circulation channel 91 or the pump 99 may be operated intermittently.

  The total volume of the denitrification tanks 41, 41,... May be set according to the hydraulic residence time (HRT) and the nitrate nitrogen concentration to be targeted.

Target value of the concentration of nitrate nitrogen in breeding water W ₀ may be appropriately set according to the type of breeding an organism, but 25 ^- if the target (NO ₃ -N mg / L) or less, de the total capacity of the denitrification tank 41, and at least 2% of the volume of the breeding water W ₀ in the breeding aquarium T, 5 a proportion of the breeding water W ₀ to be supplied to the denitrification unit 4 from the breeding aquarium T of breeding water is water intake It is desirable to set it to ˜20%. In order to save the space of the denitrification means 4, it is desirable that the total capacity of the denitrification tank 41 is less than 5% of the volume of the breeding water W ₀ in the breeding water tank T. while achieving space saving also in the rearing water W ₀ nitrate nitrogen concentration of 25 ^- in order to maintain the (NO ₃ -N mg / L) or less, breeding water W ₀ to be supplied to the denitrification unit 4 It is desirable to set the ratio of 5 to 10% of the breeding water taken from the breeding tank T.

  The dominant species of denitrifying bacteria in the denitrification tank 41 are the genus Thauera, the genus Sedimenticola, the genus Arcobactor, and the like. The genus Thauera is an acetic acid-assimilating denitrifying bacterium and is also known as an aromatic compound-degrading bacterium.

The physical filtration means 5 physically captures organic substances such as proteins. The physical filtration means 5 is provided in parallel with the nitrification means 1. That is, the physical filtration means 5 is provided in the middle of a physical filtration flow path 93 that bypasses the nitrification means 1, and the breeding water W _{5 that} has passed through the physical filtration means 5 is supplied to the water temperature adjustment means 6.

  The physical filtration means 5 of this embodiment includes a protein skimmer 51, an inlet valve 52, and an outlet valve 53.

The protein skimmer 51 removes organic substances contained in the breeding water W ₀ by attaching fine bubbles generated inside to dissolved organic substances or suspended suspended substances and floating the bubbles. That is, the protein skimmer 51 physically captures organic matter and the like.

The inlet valve 52 adjusts the amount of breeding water W ₀ flowing into the protein skimmer 51, and the outlet valve 53 regulates the amount of breeding water W ₅ flowing out from the protein skimmer 51 into the physical filtration channel 93. To do.

The water temperature adjusting means 6 adjusts the water temperature of the breeding water W ₁ , W ₅ that has passed through the nitrification means 1 and the physical filtration means 5 to an appropriate temperature, and is provided downstream of the nitrification means 1 and the physical filtration means 5. . The water temperature adjusting means 6 of the present embodiment is provided in the middle of the circulation channel 91, and the breeding water W _{6 that} has passed through the water temperature adjusting means 6 is supplied to the sterilizing means 7. In addition, there is no restriction | limiting in the structure of the water temperature adjustment means 6, It can comprise with a heater, a cooler, a heat exchanger etc. When the water temperature is not adjusted, the water temperature adjusting means 6 may be omitted.

The sterilizing means 7 is used to kill microorganisms, bacteria, viruses and the like contained in the breeding water W ₆ that has passed through the water temperature adjusting means 6, and is provided downstream of the water temperature adjusting means 6. The sterilizing means 7 of this embodiment is provided in the middle of the circulation channel 91, and the breeding water W _{7 that} has passed through the sterilizing means 7 is supplied to the oxygen supply means 8. In addition, there is no restriction | limiting in the sterilization method, For example, an ultraviolet-ray, ozone, chlorine etc. can be used. If sterilization is not performed, the sterilization means 7 may be omitted.

The oxygen supply means 8 supplies oxygen to the breeding water W ₇ that has passed through the sterilization means 7, and is provided downstream of the sterilization means 7. That is, the oxygen supply means 8 is for adjusting the dissolved oxygen amount of breeding water W ₈ should be returned to the rearing water tank T (DO) and redox potential (ORP). There is no restriction | limiting in the structure of the oxygen supply means 8, It is good also as an aeration system and it is good also as an aeration system. The oxygen supply means 8 is a means necessary when the breeding water W ₇ that has passed through the sterilization means 7 is anaerobic, so that the aerobic breeding water W ₇ can be stably obtained. , May be omitted.

  The circulation means includes flow paths 91 to 96 and pumps 97 to 99. In this embodiment, pumps 97 and 98 are provided in the middle of the circulation passage 91 (in the present embodiment, upstream of the nitrification means 1 and downstream of the oxygen supply means 8), and in the middle of the denitrification passage 92 (this embodiment). Although the pump 99 is provided upstream of the denitrification means 4 in the form, it is not intended to limit the position and number of pumps. Moreover, the branch position and the merge position of the flow paths 91 to 96 can be changed as appropriate.

The water treatment apparatus A according to this embodiment described above purifies the breeding water using nitrification by nitrifying bacteria and denitrification by denitrifying bacteria. According to this water treatment apparatus A, denitrification is performed. since breeding water W ₄ which has passed through the unit 4 is supplied to the nitrification unit 1, it is possible to stably removed, continuously ammonium nitrogen and nitrate nitrogen and the like. That is, according to the water treatment apparatus A, it is possible to reduce the frequency of water change and replenishment, and as a result, to reduce the maintenance cost of the breeding aquarium T (for example, the cost of taking and transporting seawater). Is possible.

  Further, according to the water treatment apparatus A, even if nitrite nitrogen or ammonia nitrogen is generated in the denitrification means 4 due to an unexpected failure, it is nitrified in the nitrification means 1, so nitrite nitrogen The risk of ammonia nitrogen flowing into the rearing tank T or drainage can be reduced. Further, since nitrification by nitrifying bacteria is carried out under aerobic conditions, even if the dissolved oxygen concentration is lowered in the denitrification means 4, it can be recovered, and therefore water with a low dissolved oxygen concentration is kept in the breeding aquarium. T and the risk of entering wastewater can be reduced.

In this embodiment, the nitrification means 1 is provided in the middle of the circulation channel 91, and all the breeding water that has passed through the nitrification means 1 is circulated to the breeding aquarium T, so that the amount of seawater replenishment is reduced or zero. Is possible. Further, since the denitrification means 4 is provided in a flow path different from the circulation flow path 91, the purification of the breeding water by the nitrification means 1 can be continued even during maintenance of the denitrification means 4. In this way, it is possible to continue the purification of the rearing water W ₀ by nitrification unit 1 during maintenance denitrification unit.

Moreover, according to the water treatment apparatus A, the organic matter captured by the nitrifying bacteria carrier 12 can be recovered, and the recovered organic matter can be used as a carbon source (food) for denitrifying bacteria. it is possible to omit or reduce the trouble of sewage polluted water generated with the news, because leads to savings of organic materials and electron donor required for denitrifying bacteria, according to the purifying breeding water W ₀ Costs can be reduced.

  Moreover, in the water treatment apparatus A, the organic matter obtained by back-washing the nitrifying bacteria carrier 12 is decomposed by the decomposition means 3 and the solubilized organic matter is supplied to the denitrification means 4, so that it is easily taken into the denitrification bacteria. As a result, the activity and proliferation of denitrifying bacteria become active.

  Moreover, according to the water treatment apparatus A, since a plurality of denitrification tanks 41, 41,... Are provided in parallel, it is possible to increase the amount of denitrification compared to the case where a single denitrification tank 41 is provided. Become.

  In this embodiment, 1 to 20% of the amount of breeding water taken from the breeding aquarium T is supplied to the denitrification means 4. In this way, the concentration of the nitrogen compound in the breeding aquarium T is raised. It can be kept at a concentration suitable for the growth of organisms.

  In this embodiment, the case where the nitrifying carrier 12 in the nitrifying unit 1 is backwashed is illustrated, but the physical filtering unit 5 is backwashed together with or in place of the nitrifying carrier 12. Also good. For example, although illustration is omitted, if the backwash water supply means 2 and the decomposition means 3 are connected to the physical filtration means 5, the protein of the physical filtration means 5 is obtained by the backwash water sent from the backwash water supply means 2. The skimmer 51 is backwashed, and the backwash water that has passed through the protein skimmer 51 is supplied to the decomposition means 3. When the protein skimmer 51 is backwashed, the inlet valve 52 and the outlet valve 53 are closed.

In the present embodiment, a part of the breeding water W ₀ taken from the breeding water tank T is supplied to the denitrification means 4, and the breeding water W ₄ that has passed the denitrification means 4 is taken from the breeding water tank T. _Although the case of supplying to the nitrification means 1 together with ₀ is illustrated, the denitrification flow path 92 ′ extending from the downstream side of the nitrification tank 11 to the upstream side of the nitrification tank 11 as in the water treatment apparatus A ′ shown in FIG. the denitrification unit 4 is provided, a part of the breeding water W ₁ which has passed through the nitrification means 1 is supplied to the denitrification unit 4, and intake from breeding aquarium T the total amount of breeding water W ₄ which has passed through the denitrification device 4 rearing with water W ₀ may be supplied again to the nitrification unit 1. The denitrification means 4 in the water treatment apparatus A ′ is supplied with the breeding water W ₀ in the breeding tank T through the nitrification means 1, and the nitrification means 1 directly supplies the breeding water W ₀ in the breeding tank T manner with receiving a supplied with breeding water W ₄ which has passed through the denitrification device 4 _(rearing water W ₄ denitrification treatment by denitrifying bacteria was _made). Some of nitrifying means 1 breeding water W ₁ which has passed through the _(breeding water nitrification treatment by nitrification bacteria is made W ₁₎ is supplied to the denitrification unit 4, the balance is reflux breeding aquarium T. The denitrification flow path 92 ′ joins the circulation flow path 91 on the downstream side of the branch point between the circulation flow path 91 and the physical filtration flow path 93. Therefore, the breeding water W that has passed through the denitrification means 4 is used. All of ₄ is supplied to the nitrification means 1.

The amount of the breeding water W ₁ supplied to the denitrification unit 4 is desirably set to ₁ to 20%, more preferably 5 to 10% of the breeding water W ₁ that has passed through the nitrification unit 1. That is, it is desirable to supply ₁ to 20%, more preferably 5 to 10%, of the breeding water W ₁ that has passed through the nitrification means 1 to the denitrification means 4 and supply the rest to the water temperature adjustment means 6. If it does in this way, the density | concentration of the nitrogen compound in the breeding water tank T can be kept at the density | concentration suitable for growth of a breeding organism.

A, A 'Water treatment apparatus 1 Nitrification means 2 Backwash water supply means 3 Decomposition means 4 Denitrification means 5 Physical filtration means 91 Circulation flow path 92 Denitrification flow path T Breeding water tank W ₀ Breeding water

Claims (2)

A circulation channel starting from the rearing tank and returning to the rearing tank;
Nitrification means provided in the middle of the circulation flow path for nitrification by nitrifying bacteria,
A flow path for denitrification from the rearing tank to the upstream side of the nitrification means,
A denitrification means provided in the denitrification flow path and denitrifying by denitrifying bacteria, and a water treatment device comprising:
The denitrification unit is supplied with breeding water breeding water tank without going through the nitrification unit,
The nitrification means receives the supply of breeding water in the breeding aquarium, and receives breeding water that has been denitrified by the denitrifying bacteria,
A water treatment apparatus, wherein all of the breeding water that has been nitrified by the nitrifying bacteria is circulated to the breeding aquarium. A circulation channel starting from the rearing tank and returning to the rearing tank;
Nitrification means provided in the middle of the circulation flow path for nitrification by nitrifying bacteria,
A flow path for denitrification from the downstream side of the nitrification means to the upstream side of the nitrification means,
A denitrification means provided in the denitrification flow path and denitrifying by denitrifying bacteria, and a water treatment device comprising:
The denitrification unit is supplied with breeding water of rearing water tank via the nitrification unit,
The nitrification means receives the supply of breeding water in the breeding aquarium, and receives breeding water that has been denitrified by the denitrifying bacteria,
A water treatment apparatus characterized in that part of the breeding water that has been nitrified by the nitrifying bacteria is supplied to the denitrification means, and the remainder is circulated to the breeding aquarium.

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