JP6947602B2 - Water treatment equipment and water treatment method - Google Patents

Description

The present invention relates to a water treatment apparatus and a water treatment method for treating breeding water for aquatic organisms.

The breeding water used for breeding aquatic organisms in aquariums, aquaculture farms, etc. usually contains suspended solids, organic matter, ammonia nitrogen, etc. in association with the breeding of aquatic organisms. It is important to remove suspended solids and the like in the breeding water of aquatic organisms in order to maintain the health of aquatic organisms.

For example, in Patent Document 1, suspended from breeding water containing residual feed, feces, ammonia excreted by breeding fish, organic excrement, etc., extracted from the breeding tank of a closed-circulation aquaculture device for breeding fish and shellfish. When breeding aquaculture fish using a closed circulation aquaculture device equipped with a membrane separation activated sludge treatment device as a device for separating or decomposing substances and excreted substances, particles are placed in the aeration tank of the membrane separation activated sludge treatment device. A method for raising fish and shellfish that is operated by adding activated charcoal has been proposed.

Japanese Unexamined Patent Publication No. 2011-130685

However, in the case of a membrane separation activated sludge treatment device, the surface of the membrane may be contaminated by the growth of bacteria living in the breeding water, organic substances in the breeding water, etc., and fouling may occur in which the pores are blocked. .. In particular, when trying to treat breeding water containing ammoniacal nitrogen such as ammonia, nitrogen becomes a nutrient source for bacteria and may promote fouling. When the ammonia concentration in the breeding water becomes high, it is toxic to fish and the like, so it is desirable to remove it.

Therefore, an object of the present invention is to provide a water treatment apparatus and a water treatment method capable of suppressing fouling and stably treating breeding water.

The present invention is a water treatment apparatus for treating breeding water of aquatic organisms, which comprises a reaction tank to which the breeding water is supplied, an immersion type filter membrane which is immersed in the reaction tank and filters the breeding water. An ozone treatment means for supplying ozone to the reaction tank to treat the breeding water with ozone, a treated water tank in which the treated water filtered by the immersion type filtration membrane is stored, and a treated water tank stored in the treated water tank. The immersion type filtration film is used by using the peroxide decomposition treatment means for decomposing the peroxide generated by the ozone treatment and the treated water stored in the treated water tank, which are contained in the treated water. The immersion type filter membrane is a ceramic filter membrane, and the breeding water supplied to the reaction tank is breeding water from a tank for breeding aquatic organisms. It is a water treatment apparatus having a return means for returning the treated water in which the peroxide is decomposed by the peroxide decomposition treatment means to the water tank.

Further, in the water treatment apparatus, the breeding water is preferably seawater.

Further, in the water treatment apparatus, it is preferable that the breeding water is the breeding water of an inland aquarium.

Further, in the water treatment apparatus, the peroxide decomposition treatment means is preferably an activated carbon treatment apparatus.

Further, the present invention is a water treatment method for treating breeding water of aquatic organisms, which comprises a filtration step of filtering the breeding water by an immersion type filtration membrane immersed in a reaction tank to which the breeding water is supplied. An ozone treatment step of supplying ozone into the reaction tank and treating the breeding water with ozone, a step of storing the treated water filtered by the filtration step in the treated water tank, and the step of storing the treated water in the treated water tank. The immersion type filtration membrane is reversed by using the peroxide decomposition treatment step of decomposing the peroxide generated by the ozone treatment contained in the treated water and the treated water stored in the treated water tank. The immersion type filter membrane is a ceramic filter membrane, and the breeding water supplied to the reaction tank is breeding water from a tank for breeding aquatic organisms. It is a water treatment method including a return step of returning the treated water in which the peroxide is decomposed by the peroxide decomposition treatment step to the water tank.

Further, in the water treatment method, the breeding water is preferably seawater.

Further, in the water treatment method, it is preferable that the breeding water is the breeding water of an inland aquarium.

Further, in the water treatment method, in the peroxide decomposition treatment step, the peroxide generated by the ozone treatment contained in the treated water filtered by the filtration step can be decomposed by the activated carbon treatment apparatus. preferable.

According to the present invention, fouling can be suppressed and breeding water can be treated stably.

It is a schematic block diagram which shows an example of the water treatment apparatus which concerns on this embodiment. It is a schematic block diagram which shows another example of the water treatment apparatus which concerns on this embodiment.

Embodiments of the present invention will be described below. The present embodiment is an example of carrying out the present invention, and the present invention is not limited to the present embodiment.

FIG. 1 is a schematic configuration diagram showing an example of a water treatment apparatus according to the present embodiment. The water treatment device 1 shown in FIG. 1 includes a reaction tank 10, an immersion type film module 12 immersed in the reaction tank 10, an ozone treatment device 14, a treatment water tank 16, a circulation pump 18, a suction pump 20, and pipes 22a and 22b. It includes 22c, an ozone discharge pipe 24, a return pump 26, a backwash pump 28, and a backwash pipe 30.

The ozone treatment device 14 shown in FIG. 1 includes an ozone generator 32, an ozone supply pipe 34, and an air diffuser 36. The air diffuser 36 is installed in the reaction tank 10. The ozone generator 32 and the air diffuser 36 are connected by an ozone supply pipe 34. The ozone treatment device 14 shown in FIG. 1 is an example of ozone treatment means. The ozone treatment means is not particularly limited as long as it can generate ozone and supply the ozone into the reaction vessel 10.

The immersion type membrane module 12 shown in FIG. 1 includes an immersion type filtration membrane 38 and a water collecting pipe 40. The immersion type filtration membrane 38 is installed in the reaction tank 10. The immersion type filtration membrane 38 may be single or plural. The water collecting pipe 40 is installed at the upper end of the immersion type filtration membrane 38. The immersion type filtration membrane 38 shown in FIG. 1 has, for example, a water collection space in which treated water that has permeated the membrane flows into the immersion type filtration membrane 38, and has a water collection pipe 40 installed at the upper end of the immersion type filtration membrane 38. Communicating. The immersion type membrane module 12 shown in FIG. 1 is an example, and is not particularly limited as long as it includes the immersion type filtration membrane 38 immersed in the reaction vessel 10.

In the water treatment apparatus of FIG. 1, the outlet of the water tank 41 and the inlet of the reaction tank 10 are connected by a pipe 22a via a circulation pump 18. Further, the outlet of the water collecting pipe 40 and the inlet of the treatment water tank 16 are connected by a pipe 22b via a suction pump 20. Further, the outlet of the treatment water tank 16 and the inlet of the water tank 41 are connected by a pipe 22c via a return pump 26. Further, the backwash outlet of the treatment water tank 16 and the pipe 22b are connected by the backwash pipe 30 via the backwash pump 28. Further, an ozone discharge pipe 24 is connected to the reaction tank 10.

The operation of the water treatment device 1 of FIG. 1 will be described.

In the aquarium 41, aquatic organisms such as fish are bred in the breeding water. Examples of the breeding water include an exhibition tank installed in an aquarium, aquaculture tank, aquarium water such as a live fish tank, and the like, and may be fresh water or seawater. The breeding water usually contains suspended solids, organic matter, ammonia nitrogen and the like with the breeding of aquatic organisms.

The breeding water in the water tank 41 is supplied to the reaction tank 10 through the pipe 22a by the circulation pump 18. Further, when a suction pressure is applied to the immersion type filtration film 38 by the suction pump 20 installed in the pipe 22b, the breeding water in the reaction tank 10 is filtered by the immersion type filtration film 38 (filtration step). As a result, suspended solids and the like in the breeding water are removed by the immersion type filtration membrane 38, and the treated water that has permeated through the immersion type filtration membrane 38 collects in the internal space (secondary side (treated water side)) in the membrane. It is supplied to the treatment water tank 16 through the water pipe 40 and the pipe 22b.

Further, ozone generated by the ozone generator 32 is supplied to the reaction tank 10 through the ozone supply pipe 34 and the air diffuser 36, and the breeding water in the reaction tank 10 is treated with ozone (ozone treatment step). The discharged ozone is discharged through the ozone discharge pipe 24.

The ozone treatment is a treatment in which the breeding water in the reaction tank 10 is brought into contact with ozone, whereby microorganisms, organic substances and the like in the breeding water are decomposed. When the breeding water contains a halide ion, as described below, a peroxide such as a halogen oxo acid generated by the reaction between the halide ion and ozone causes ammonia nitrogen such as ammonia. Is disassembled. Since seawater and fresh water are used as the breeding water, halide ions are usually contained.

An example of the decomposition reaction of ammonia nitrogen by ozone treatment will be described below.

As shown in the following formula 1, a halogen oxo acid such as hypohalogenate (HXO), which is a peroxide, is generated by the reaction between the halide ion contained in the breeding water and ozone.

[Equation 1]
X ⁻ + O ₃ → O ₂ + OX ⁻
OX ⁻ + H ₂ O → HXO + OH ⁻
(Here, X ⁻ is a halide ion such as chloride ion (Cl ⁻ ), bromide ion (Br ⁻ ), iodide ion (I ⁻ ), and X is a halogen such as Cl, Br, I. be.)

When X ⁻ is a chloride ion, as shown in the following formula 2, a halogen oxo acid such as hypochlorous acid (HClO), which is a peroxide, is generated by the reaction between the chloride ion contained in the breeding water and ozone. appear.

[Equation 2]
^{_{Cl - + O 3 → O 2}} + OCl -
OCl ⁻ + H ₂ O → HClO + OH ⁻

When X ⁻ is a bromide ion, as shown in the following formula 3, halogen oxo acids such as hypobromous acid (HBrO), which is a peroxide, are generated by the reaction between the bromide ion contained in the breeding water and ozone. appear.
[Equation 3]
Br ⁻ + O ₃ → O ₂ + OBr ⁻
OBr ⁻ + H ₂ O → HBr O + OH ⁻

Then, as shown in the following formula 4, the generated halogen oxo acid such as hypochlorous acid decomposes the ammonia nitrogen contained in the breeding water.

[Equation 4]
HXO + NH ₃ → NH ₂ X + H ₂ O
3HXO + 2NH ₃ → 2N ₂ + 3HX + 3H ₂ O
(Here, X is a halogen such as Cl, Br, I, etc.)

In particular, when X is Br, the generated hypobromous acid easily decomposes the ammonia nitrogen contained in the breeding water (see the following formula 5).

[Equation 5]
HBrO + NH ₃ → NH ₂ Br + H ₂ O
3HBrO + 2NH ₃ → 2N ₂ + 3HBr + 3H ₂ O

As described above, in the water treatment apparatus 1 shown in FIG. 1, not only the breeding water is filtered by the immersion type filtration membrane 38 immersed in the reaction tank 10 to remove suspended solids and the like in the breeding water, but also the reaction tank is used. The breeding water in No. 10 is treated with ozone to decompose bacteria, organic substances, ammonium nitrogen, etc. that live in the breeding water. Therefore, the surface of the immersion filtration membrane 38 is contaminated by bacteria, organic substances, ammonia nitrogen, and the like, and fouling that closes the pores is suppressed, so that stable treatment of the breeding water becomes possible.

In the water treatment apparatus 1 shown in FIG. 1, a part of the treated water stored in the treated water tank 16 is returned to the water tank 41 through the pipe 22c by the return pump 26, but the treated water tank 16 is above the water tank 41. In that case, it may be returned by natural flow without using a return pump. The treated water may be discharged to the outside of the system of the water treatment device 1 without being returned to the water tank 41.

When it becomes necessary to wash the immersion type filtration membrane 38, it is preferable to perform a backwash treatment. For example, after stopping the circulation pump 18 and the suction pump 20, the backwash pump 28 is operated so that at least a part of the treated water in the treated water tank 16 is backwashed, and the backwash pipe 30, the pipe 22b, and the water collecting water are collected. It is supplied to the internal space (secondary side) of the immersion type filtration membrane 38 through the pipe 40 and permeates through the primary side of the immersion type filtration membrane 38. The timing of backwashing is not particularly limited, and for example, it may be carried out at predetermined fixed time intervals or at predetermined fixed intervals of the amount of filtered water.

In the water treatment apparatus 1 shown in FIG. 1, the treatment water tank 16 is not an indispensable configuration, but it is desirable to install the treatment water tank 16 in terms of carrying out a backwashing step on the immersion type filtration membrane 38.

Filtration by the immersion type membrane module 12 is not limited to the suction type filtration process by the suction pump 20, but is a siphon type using the siphon action due to the water level difference between the water level of the reaction tank 10 and the water level of the treatment water tank 16. It may be filtered or the like.

The material of the immersion type filtration film 38 is, for example, a ceramic material such as alumina, silica, titania, zirconia, mullite, spinel, or a mixture thereof, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyether monkey. Examples thereof include organic materials such as phone (PES) and cellulose acetate (CA). The immersion type filtration membrane 38 is preferably a ceramic filtration membrane in that it has ozone resistance, toughness, and can be filtered with a low water flow differential pressure.

Examples of the shape of the immersion type filtration membrane 38 include a tubular shape, a flat membrane shape, a hollow fiber membrane shape, and a spiral shape. Examples of the type of the immersion type filtration membrane 38 include an ultrafiltration membrane (UF membrane) and a microfiltration membrane (MF membrane). Regarding the combination of the material, shape, and type of the immersion type filtration membrane 38, it is made of ceramic and has a flat membrane-like precision filtration in that it suppresses the ozone resistance, toughness, and decrease of the filtration flux of the immersion type filtration membrane 38. It is preferably a membrane.

FIG. 2 is a schematic configuration diagram showing another example of the water treatment apparatus according to the present embodiment. In the water treatment apparatus 2 shown in FIG. 2, the same reference numerals are given to the same configurations as those of the water treatment apparatus 1 shown in FIG. 1, and the description thereof will be omitted. The water treatment device 2 shown in FIG. 2 includes an activated carbon treatment device 42, a pipe 22d, and a return pump 44 as peroxide decomposition treatment means, in addition to the configuration of the water treatment device 1 shown in FIG. The activated carbon treatment device 42 is, for example, an activated carbon packed tower filled with activated carbon.

In the water treatment device 2 of FIG. 2, the outlet of the treatment water tank 16 and the inlet of the activated carbon treatment device 42 are connected by a pipe 22c via a return pump 26. Further, the outlet of the activated carbon treatment device 42 and the inlet of the water tank 41 are connected by a pipe 22d via a return pump 44. If water can be passed through the activated carbon treatment device 42 using gravity, the return pump 26 and the return pump 44 can be removed.

The treated water filtered by the immersion type filtration membrane 38 is stored in the treated water tank 16 and then supplied to the activated carbon treatment device 42 through the pipe 22c by the return pump 26. The treated water supplied to the activated charcoal treatment apparatus 42 may contain a peroxide such as halogen oxo acid generated by the above-mentioned ozone treatment, but the peroxide such as halogen oxo acid is treated with activated carbon. It is decomposed by the apparatus 42 (peroxide decomposition treatment step). The treated water in which the peroxide has been decomposed is returned to the water tank through the pipe 22d by the return pump 44 (return step).

If the concentration of peroxide in the treated water filtered by the immersion type filtration film 38 becomes high, there is a concern that it may affect the ecology, etc., but as shown in FIG. 2, activated carbon is placed after the immersion type filtration film 38. By installing the treatment device 42, the peroxide is decomposed, so that the influence on the living body can be reduced even if the peroxide is discharged to the outside of the system without being returned to the water tank 41. Further, even if the treated water in which the peroxide is decomposed is returned to the water tank 41, the influence on aquatic organisms can be reduced. Furthermore, it will lead to reduction of running cost.

Examples of the peroxide decomposition means include a filling tower filled with a peroxide-supporting carrier, a peroxide decomposition catalyst such as titanium oxide and platinum, and the like in addition to the activated carbon treatment apparatus 42, and the activated carbon treatment is performed from the viewpoint of cost and the like. Device 42 is preferred.

The water treatment device of the present embodiment is used in an aquarium, a farm, or the like for treating the breeding water used for breeding aquatic organisms, and is particularly suitable for use in an inland aquarium. Is. Further, the water treatment apparatus of the present embodiment is particularly suitable for the treatment of seawater containing ammonia nitrogen among the treatments of breeding water for aquatic organisms. Since seawater usually contains bromide ions, the water treatment apparatus of the present embodiment can easily decompose ammonia nitrogen in seawater by ozone-treating the seawater in the reaction vessel in which the immersion type filtration membrane is immersed. can do. When attempting to decompose (nitrify and denitrify) ammonia nitrogen by biological treatment, first, ammonia nitrogen is converted to nitric acid by aerobic biological treatment, and then nitric acid is reduced to nitric acid by anaerobic biological treatment. It is normal to remove nitrogen from the water. That is, when biological treatment is used, a nitrification tank under aerobic conditions and a denitrification tank under anaerobic conditions are required, so that a large installation space is required. However, in the water treatment apparatus according to the present embodiment, decomposition (nitrification and denitrification) of ammonia nitrogen can be performed in one tank (reaction tank 10), so that space can be saved.

1,2 water treatment equipment, 10 reaction tanks, 12 immersion type membrane module, 14 ozone treatment equipment, 16 treatment water tanks, 18 circulation pumps, 20 suction pumps, 22a to 22d pipes, 24 ozone discharge pipes, 26,44 return pumps, 28 backwash pump, 30 backwash pipe, 32 ozone generator, 34 ozone supply pipe, 36 air diffuser, 38 immersion type filter membrane, 40 water collection pipe, 41 water tank, 42 activated charcoal treatment equipment.

Claims (8)

A water treatment device that treats breeding water for aquatic organisms.
A reaction tank to which the breeding water is supplied, an immersion type filtration membrane that is immersed in the reaction tank and filters the breeding water, and ozone that supplies ozone into the reaction tank to treat the breeding water with ozone. Decomposes the peroxide generated by the ozone treatment contained in the treatment means, the treated water tank in which the treated water filtered by the immersion type filtration membrane is stored, and the treated water stored in the treated water tank. The peroxide decomposition treatment means to be treated and the backwash treatment means for backwashing the immersion type filtration film using the treated water stored in the treated water tank are provided .
The immersion type filtration membrane is a ceramic filtration membrane.
The breeding water supplied to the reaction tank is breeding water from a water tank for breeding aquatic organisms, and the treated water obtained by decomposing the peroxide by the peroxide decomposition treatment means is returned to the water tank. A water treatment apparatus characterized by having means. The water treatment apparatus according to claim 1, wherein the breeding water is seawater. The water treatment apparatus according to claim 1 or 2, wherein the breeding water is breeding water of an inland aquarium. The water treatment apparatus according to any one of claims 1 to 3, wherein the peroxide decomposition treatment means is an activated carbon treatment apparatus. It is a water treatment method that treats the breeding water of aquatic organisms.
A filtration step of filtering the breeding water by an immersion type filtration membrane immersed in the reaction tank to which the breeding water is supplied, and
An ozone treatment step of supplying ozone into the reaction vessel and treating the breeding water with ozone,
A step of storing the treated water filtered by the filtration step in a treated water tank, and a step of storing the treated water in the treated water tank.
A peroxide decomposition treatment step for decomposing the peroxide generated by the ozone treatment contained in the treated water stored in the treated water tank, and
A backwashing treatment step of backwashing the immersion type filtration membrane using the treated water stored in the treated water tank is provided .
The immersion type filtration membrane is a ceramic filtration membrane.
The breeding water supplied to the reaction tank is breeding water from a water tank for breeding aquatic organisms, and the treated water in which the peroxide is decomposed by the peroxide decomposition treatment step is returned to the water tank. A water treatment method characterized by having a step. The water treatment method according to claim 5, wherein the breeding water is seawater. The water treatment method according to claim 5 or 6, wherein the breeding water is breeding water of an inland aquarium. The peroxide decomposition treatment process, the activated carbon treatment apparatus, according to claim 5-7, wherein the filtration contained in the treated water which has been filtered by step, characterized by decomposing peroxide generated by the ozone treatment The water treatment method according to any one of the above.

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