JP7260252B2 - solid carrier - Google Patents

Description

The present invention relates to a solid carrier used for wastewater treatment. In particular, it relates to a solid carrier as a microorganism-immobilizing carrier for holding microorganisms used in wastewater treatment.

Biological treatment using various microorganisms is generally known as a method for treating waste water containing organic matter. At this time, in order to maintain a high concentration of microorganisms and prevent the microorganisms from flowing out of the system, it is widely practiced to use a microorganism-immobilized carrier in which the microorganisms are immobilized on the carrier.

Porous substances are widely used as such microorganism-immobilizing carriers. However, when the microorganism-immobilizing carrier is simply put into the biological treatment tank, it takes a long time for water to penetrate into the fine pores of the porous material, and air remains. There is a problem that the utilization efficiency of
For example, Patent Document 1 discloses a method of impregnating a microorganism-immobilizing carrier made of a porous material with alcohol, passing it through a rotating body to separate excess alcohol from the microorganism-immobilizing carrier, and introducing the alcohol into a biological treatment tank. A dosing device is described. In addition, Patent Document 1 discloses that when a microorganism-immobilized carrier is put into a biological treatment tank, the water to be treated and the microorganisms in the water to be treated can quickly enter into the fine pores of the porous material. Are listed.

JP-A-9-122675

However, the method described in Patent Document 1 has the problem that the alcohol impregnated in the microorganism-immobilized carrier remains, leading to suppression of the activity of microorganisms, and the expected treatment efficiency cannot be obtained. . Moreover, since it is necessary to use a large amount of a solvent such as alcohol, there arises a problem of high cost.

In addition, when a carrier using a porous substance is used in a wastewater treatment tank, not only the carrier for immobilizing microorganisms, if air remains in the fine pores of the porous substance, it only reduces the utilization efficiency of the carrier interface. Otherwise, the carrier floats to the surface of the water in the treatment tank, and there is also a problem that the treatment efficiency in the treatment tank is lowered.

An object of the present invention is to enable solid carriers used for wastewater treatment to be treated in a state in which residual air in the solid carriers is suppressed without using a solvent or the like that affects the activity of microorganisms. It is to provide a solid carrier.

As a result of intensive studies on the above-mentioned problems, the present inventors have found that a solid carrier comprising a porous carrier and a filler to be filled in the voids of the porous carrier eliminates solvents and the like that affect the activity of microorganisms. The present invention has been completed by discovering that it is possible to use for wastewater treatment in a state in which air remains in the solid carrier is suppressed without using the solid carrier.
That is, the present invention is the following solid carrier.

The solid carrier of the present invention for solving the above problems is characterized in that it comprises a porous carrier and a filler that fills the voids of the porous carrier.
In the solid carrier of the present invention, filling the voids of the porous carrier with a filler reduces the space in which air enters the solid carrier, thereby suppressing air remaining in the solid carrier. can. Therefore, when this solid carrier is subjected to wastewater treatment, it is possible to suppress a decrease in the utilization efficiency of the carrier interface due to the air in the solid carrier, floating of the carrier, and the like.

In one embodiment of the solid carrier of the present invention, the filler is characterized by being soluble in water or decomposed by microorganisms.
According to this feature, after the solid carrier is put into the waste water treatment tank, the filler filled in the voids of the porous carrier is removed, so that air does not enter the solid carrier and the solid It is possible to increase the utilization efficiency of the carrier interface.

Moreover, one embodiment of the solid carrier of the present invention is characterized in that the filler contains particulate matter having a diameter of 1 μm or more.
According to this feature, the size of the voids between the porous carriers can be controlled. In addition, this makes it possible to form voids into which microorganisms can easily enter, and in particular, it is possible to enhance the effect of retaining microorganisms as a microorganism-immobilizing carrier.

Moreover, one embodiment of the solid carrier of the present invention is characterized in that the filler contains a plurality of substances with different particle sizes.
According to this feature, a plurality of sizes of voids can be provided between the porous carriers. This makes it possible to increase the specific surface area of the solid support and improve the utilization efficiency of the interface of the solid support.

Further, one embodiment of the solid carrier of the present invention is characterized by containing a plurality of substances having different dissolution rates in water or decomposition rates by microorganisms.
According to this feature, voids into which microorganisms can easily enter are rapidly formed in the solid carrier, while the substance serving as a nutrient source for microorganisms remains in the voids of the porous carrier, thereby inhibiting the growth of microorganisms. By preparing a suitable environment, it becomes possible to enhance the effect of retaining microorganisms as a microorganism-immobilizing carrier.

According to the present invention, a solid carrier used for wastewater treatment can be treated in a state in which residual air in the solid carrier is suppressed without using a solvent or the like that affects the activity of microorganisms. A product carrier can be provided.

1 is a schematic illustration of a solid carrier according to a first embodiment of the present invention; FIG. (A) A schematic illustration of a solid carrier before being subjected to wastewater treatment (in a state of preservation). (B) A schematic illustration of the solid carrier after being subjected to waste water treatment (inside the treatment tank). 1 is a schematic illustration of a wastewater treatment tank using a solid carrier according to the first embodiment of the present invention; FIG. 1 is a schematic representation of a solid support according to a second embodiment of the invention; (A) A schematic illustration of a solid carrier before being subjected to wastewater treatment (in a state of preservation). (B) A schematic illustration of the solid carrier after being subjected to waste water treatment (inside the treatment tank). FIG. 3 is a schematic illustration of a solid carrier according to a third embodiment of the present invention; (A) A schematic illustration of a solid carrier before being subjected to wastewater treatment (in a state of preservation). (B) A schematic illustration of the solid carrier after being subjected to waste water treatment (inside the treatment tank).

The solid carrier of the present invention is suitably used as a microorganism-immobilizing carrier in biological treatment of wastewater.

The biological treatment of waste water may be either anaerobic biological treatment or aerobic biological treatment. For example, anaerobic biological treatment includes methane fermentation using acidogenic bacteria and methanogenic bacteria, denitrification treatment that reduces nitric acid and nitrite using denitrifying bacteria, and sulfuric acid reduction treatment that reduces sulfuric acid using sulfate reducing bacteria. are mentioned. Further, examples of aerobic biological treatment include activated sludge treatment using activated sludge.

Hereinafter, embodiments of the solid carrier according to the present invention will be described in detail with reference to the drawings.
It should be noted that the solid carriers described in the embodiments are merely examples for explaining the solid carriers according to the present invention, and are not limited to these.

[First embodiment]
FIG. 1 is a schematic illustration of a solid carrier 1a according to the first embodiment of the present invention. Note that FIG. 1(A) is a schematic illustration of the solid carrier before being subjected to wastewater treatment (in a state of storage), and FIG. 1(B) is a solid material after being subjected to wastewater treatment (in the treatment tank) 1 is a schematic illustration of a carrier; FIG.
A solid carrier 1a according to the present invention comprises a porous carrier 2 and fillers 3 filled in voids S of the porous carrier 2, as shown in FIG. 1(A). Accordingly, since the gaps S of the solid carrier 1a are filled with the filler 3, inclusion of air in the gaps S can be suppressed.
In addition, the solid carrier 1a is a microorganism-immobilized carrier that retains useful microorganisms M that are suitably used for wastewater treatment or the like. It will be suitably used for biological treatment that comes into contact with.

Considering the wastewater treatment process and the separation/recovery/regeneration process after wastewater treatment, the solid support 1a preferably maintains a constant shape and has strength. Since a crosslinked structure such as gel may be destroyed by the growth of microorganisms M, the solid carrier 1a of the present invention is preferably a solid molded body or a sintered body. As a result, the solid carrier 1a of the present invention can be used repeatedly in wastewater treatment.

The size of the solid carrier 1a of the present invention is not particularly limited, and may be appropriately designed according to the use. For example, as for the size of the solid carrier 1a, the sum of width, depth and height (total of three sides) is 10 to 30 mm. When the solid carrier 1a is used as a microorganism-immobilizing carrier, the lower limit is preferably 1 mm or more, more preferably 5 mm or more, from the viewpoint of increasing the adhesion of microorganisms M. The upper limit is preferably 150 mm or less, more preferably 90 mm or less. As a result, a sufficient number of microorganisms M can adhere to the waste water when it is subjected to waste water treatment.

In consideration of maintaining the shape and strength of the solid carrier 1a, it is preferable that the size of the solid carrier 1a changes little due to expansion, contraction, etc. when placed in water. For example, the rate of change in size of the solid carrier 1a when immersed in water is 0 to 5%. Here, the size of the solid carrier 1a refers to the outer periphery of the solid carrier 1a, and the porosity (volume) in the solid carrier 1a may change when the solid carrier 1a is put into water. . As a result, when the solid carrier 1a is subjected to wastewater treatment, the treatment can be performed while maintaining the shape and strength of the solid carrier 1a.

The solid carrier 1a is produced as a compact using a mixture of the porous carrier 2 and the filler 3 as a raw material and using various types of molding machines. For example, an extruder, a tableting machine, a compression molding machine and the like can be mentioned.
Further, the solid support 1a is manufactured as a sintered body by sintering the obtained molded body. This makes it possible to further increase the strength of the solid support 1a.
A known binder component may be added when forming the compact or sintered body as the solid carrier 1a of the present invention.

The porous carrier 2 is not particularly limited as long as it is a solid having fine pores S1 inside and retains the microorganisms M. Specific materials include silica sand, ceramics, activated carbon, polymers, clay, incineration ash, and granulated blast furnace slag. The retention of the microorganisms M in the porous carrier 2 may be performed by the microorganisms M entering the fine pores S1 in the porous carrier 2, or by attaching the microorganisms M to the surface of the porous carrier 2. Microorganisms M may be held in the gaps S2 between the porous carriers 2 . As the porous carrier 2, porous activated carbon is particularly preferable from the viewpoint of easy adhesion of microorganisms M and easy availability.

The filler 3 fills the voids S of the porous carrier 2 . Here, as shown in FIG. 1(A), the voids S of the porous carrier 2 refer to fine pores S1 within the porous carrier 2 and/or gaps S2 between the porous carriers 2 . It should be noted that the filler 3 does not have to be filled in all of the pores S1 and the gaps S2 as long as the inflow of gas into the gaps S can be restricted.

The filler 3 may be any substance that can maintain the filled state in the voids S of the porous carrier 2 under the storage conditions of the solid carrier 1a, and is particularly preferably a solid or gelatinous substance.
Here, under the storage conditions of the solid carrier 1a, a substance that exists in a gaseous state or a liquid state that flows out of the solid carrier 1a is regarded as incapable of maintaining the packed state. Not suitable for 3. On the other hand, for example, when water or an aqueous solution is used as the filler 3 and the solid carrier 1a is stored under the temperature or pressure at which the water or the aqueous solution freezes, water or the aqueous solution can also be used as the filler 3 of the present invention. becomes possible.
As a result, the solid carrier 1a of the present invention is in a state in which the inflow of gas into the voids S of the porous carrier 2 is restricted. Therefore, when the solid carrier 1a is used for wastewater treatment, it is possible to reduce the utilization efficiency of the solid carrier 1a interface and prevent the solid carrier 1a from floating in the treatment tank due to residual air.

The filler 3 is preferably soluble in water or decomposed by microorganisms. As a result, as shown in FIG. 1B, after the solid carrier 1a is put into the treatment tank for waste water treatment, the filler 3 flows out from the gaps S of the porous carrier 2 in the treatment tank, The space inside the solid carrier 1a can be expanded without containing gas. Moreover, the microorganisms M enter and are retained in the space S from which the filler 3 has flowed out.
It should be noted that it is not necessary for all of the fillers 3 to flow out (or decompose) from the voids S of the porous carrier 2 at once after being placed in the treatment tank. ) may be performed.

Specific examples of the filler 3 include water-soluble alkali metal salts such as sodium chloride, calcium chloride, and magnesium chloride, water-soluble metal complex compounds, and water-soluble dietary fiber. Substances decomposed by microorganisms include iron compounds, sugars, biodegradable resins, and the like. In particular, from the viewpoint of availability, it is preferable to use water-soluble alkali metal salts and iron compounds.
Furthermore, when the solid support 1a is a sintered body, it is necessary to select, as the filler 3, a material capable of maintaining a state of being filled in the porous support 2 even after the sintering process. As such a filler 3, for example, alkali metal salts and iron compounds are particularly preferably used.

As the type of microorganisms M retained in the solid carrier 1a of the present invention, those known in the biological treatment of wastewater can be used. Examples include acid-producing bacteria, methanogenic bacteria, fat-degrading bacteria, sugar-degrading bacteria, and the like. By using a substance such as an iron compound that serves as a nutrient source for microorganisms as the filler 3, the microorganisms M present in the waste water W can proliferate within the solid carrier 1a, and the effects of the present invention can be favorably achieved. can demonstrate.

[Wastewater treatment tank]
FIG. 2 is a schematic illustration of a waste water treatment tank 10 using the solid carrier 1a of the first embodiment of the present invention.
A wastewater treatment tank 10 according to the present invention is a treatment tank for biologically treating wastewater from factories, sewage treatment plants, etc. As shown in FIG. In preparation, the solid carrier 1a is put into the inside of the processing tank main body 20. As shown in FIG. The solid carrier 1a is used as a microorganism-immobilized carrier holding the microorganisms M.

The wastewater treatment tank 10 performs wastewater treatment in a state in which the solid carrier 1a that has been introduced is made to flow within the treatment tank main body 20 . Specifically, as shown in FIG. 2, a waste water supply port 21 is provided at the bottom of the processing tank main body 20, and a discharge port 22 is provided at the top of the processing tank main body 20, thereby circulating flow within the processing tank main body 20. The solid carrier 1a is made to flow within the treatment tank main body 20. As shown in FIG. The solid carrier 1a of the present invention has improved sedimentation properties due to the suppression of residual air. Therefore, the solid carrier 1a can be circulated and flowed in the treatment tank main body 20 to promote contact with the waste water W, and the efficiency of treating the waste water W with the microorganisms M can be enhanced.

In addition, when a material that is soluble in water or decomposed by microorganisms is used as the filler 3, the filler 3 flows out into the waste water W in the treatment tank main body 20 as shown in FIG. 1(B). , the waste water W flows into the voids S of the porous carrier 2 . As a result, the treatment can be performed without air remaining in the solid carrier 1a.

The solid carrier 1a may be enclosed or placed in another structure (bag, plate, etc.). Moreover, the waste water treatment tank 10 may perform waste water treatment in a state where the solid carrier 1a enclosed in another structure is fixed within the treatment tank main body 20. FIG. For example, a structure in which a plurality of devices are suspended from the top of the processing tank main body 20 , a structure in which a structure is directly fixed to the wall surface or partition wall of the processing tank main body 20 , a structure in which a rod-shaped or plate-shaped support is fixed to the processing tank main body 20 . may be This makes it possible to easily replace the solid carrier 1a.

The biological treatment performed in the wastewater treatment tank 10 may be either anaerobic biological treatment or aerobic biological treatment. For example, anaerobic biological treatment includes methane fermentation treatment, denitrification treatment for reducing nitrate/nitrite, and sulfuric acid reduction treatment for reducing sulfuric acid. Moreover, an activated sludge process etc. are mentioned as an aerobic biological treatment.
When aerobic biological treatment is performed, the wastewater treatment tank 10 may be provided with an air diffuser such as a nozzle or blower for supplying water and air.

In wastewater treatment, the type of microorganism M may be selected according to the type of wastewater W to be treated. For example, microorganisms M used for anaerobic biological treatment include acidogenic bacteria, methanogenic bacteria, denitrifying bacteria, sulfate-reducing bacteria, and the like. Moreover, activated sludge etc. are mentioned as microorganisms M used for aerobic biological treatment.

The wastewater treatment tank 10 may have a known structure as a treatment tank for biological treatment of wastewater, and may be provided with various incidental equipment. For example, the wastewater treatment tank 10 is provided with internal water temperature adjusting means, pH adjusting agent charging means, and means for adding metals such as nitrogen, phosphorus, cobalt and nickel, which are nutrients required by the microorganisms M. may be

As described above, the solid carrier 1a of the present invention is formed into a molded body in which the inflow of air is suppressed before being introduced into the wastewater treatment tank 10 by filling the gaps S of the porous carrier 2 with the filler 3. It is. As a result, unlike conventional microorganism-immobilized carriers, there is no need to remove air before or during treatment from a molded article into which air has flowed during production.
In addition, it is possible to easily fill the voids S of the porous carrier 2 with the waste water W by causing the filler 3 to flow out from the voids S of the porous carrier 2 during waste water treatment. At the same time, it is possible to easily enter and retain the microorganisms M in the voids S of the porous carrier 2 . This makes it possible to increase the utilization efficiency of the solid support 1a interface.

[Second embodiment]
FIG. 3 is a schematic illustration of the solid carrier 1b of the second embodiment of the present invention. FIG. 3(A) is a schematic illustration of the solid carrier before being subjected to wastewater treatment (in a state of preservation). FIG. 3(B) is a schematic illustration of the solid carrier after being subjected to wastewater treatment (inside the treatment tank).
The solid carrier 1b of this embodiment uses particulate matter 4 of a certain size as the filler 3 in the solid carrier 1a of the first embodiment. The description of the structure of the solid carrier 1b that is the same as that of the solid carrier 1a of the first embodiment will be omitted.

The size of the particulate matter 4 is preferably larger than the size of the pores S1 of the porous carriers 2 and is preferably filled in the gaps S2 between the porous carriers 2 . Further, the particulate matter 4 is preferably water soluble or decomposed by microorganisms. As a result, as shown in FIG. 3B, after the solid carrier 1b is put into the treatment tank for waste water treatment, the filler 3 flows out from the gaps S of the porous carrier 2 in the treatment tank, The size of the gap S2 between the porous carriers 2 can be controlled.

The lower limit of the size of the particulate matter 4 is preferably 1 μm or more in diameter. As a result, a space is formed in which the microorganisms M can easily enter and be retained in the gaps S2 of the porous carrier 2 . On the other hand, the upper limit of the size of the particulate matter 4 is not particularly limited, and may be appropriately set according to the mode of use. For example, the upper limit is preferably 50 μm or less, and more preferably 20 μm or less, from the viewpoint of facilitating entry of the microorganisms M and enabling their retention.

The shape of the particulate matter 4 is not particularly limited. Examples include spheres, cubes, rectangular parallelepipeds, and the like. Crystals such as alkali metal salts are preferably used because of their easy availability.

The solid carrier 1b in this embodiment is put into the wastewater treatment tank 10 shown in the first embodiment and used for wastewater treatment. Wastewater treatment may be carried out while the solid carrier 1b is fluidized, or may be carried out while the solid carrier 1b is enclosed or placed in another structure. There may be.
Further, the wastewater treatment may be either anaerobic biological treatment or aerobic biological treatment.

[Third Embodiment]
FIG. 4 is a schematic illustration of the solid carrier 1c of the third embodiment of the present invention. FIG. 4(A) is a schematic illustration of the solid carrier before being subjected to wastewater treatment (in a state of storage). FIG. 4(B) is a schematic illustration of the solid carrier after being subjected to wastewater treatment (inside the treatment tank).
The solid carrier 1c of this embodiment contains two or more substances as the filler 3 in the solid carrier 1a of the first embodiment. For example, as shown in FIG. 4A, it includes fillers 3a and 3b. The description of the structure of the solid carrier 1c that is the same as that of the solid carrier 1a of the first embodiment will be omitted.

The fillings 3a, 3b in the solid carrier 1c may differ in material particle size and may differ in composition.

For example, as shown in FIG. 4, by selecting a combination such that the particle size of the filler 3b is larger than the particle size of the filler 3a and filling the voids S of the porous carrier 2, the filler 3a, It is possible to control so that the gap S2 between the porous carriers 2 after the outflow of 3b has a structure having a plurality of sizes. As a result, it becomes possible to increase the specific surface area of the solid carrier 1c without causing air to remain in the solid carrier 1c, and to increase the utilization efficiency of the interface of the solid carrier 1c.

Further, for example, the filler 3a is filled into the pores S1 in the porous carrier 2, and the filler 3b is filled into the gap S2 between the porous carriers 2. A combination of materials with different decomposition rates due to M may be used.
As an example, the filler 3b in the gap S2 is selected to have a high dissolution rate in water, and the filler 3a in the pore S1 is selected to have a low dissolution rate in water and serve as a nutrient source for microorganisms. When the solid carrier 1c is put into the tank, the gap S2 is quickly filled with the waste water W to form an entry path for the microorganisms M. After that, the microorganisms M proliferate in the solid carrier 1c using the filler 3a as a nutrient source. You may make it build the environment which is easy to do.

The solid carrier 1c in this embodiment is put into the wastewater treatment tank 10 shown in the first embodiment and used for wastewater treatment. Wastewater treatment may be carried out while the solid carrier 1c is fluidized, or may be carried out while the solid carrier 1c is enclosed or placed in another structure. There may be.
Further, the wastewater treatment may be either anaerobic biological treatment or aerobic biological treatment.

In addition, the embodiment mentioned above shows an example of a solid carrier. The solid carrier according to the present invention is not limited to the above-described embodiments, and the solid carriers according to the above-described embodiments may be modified without changing the gist of the claims.

The solid carrier of this embodiment may be used for purposes other than microorganism-immobilized carriers in wastewater treatment. For example, it can be used as an adsorbent in wastewater treatment.

The solid carrier of the present invention is used for wastewater treatment. In particular, the solid carrier of the present invention is suitably used as a microorganism-immobilizing carrier in the biological treatment of wastewater using microorganisms.

1a, 1b solid carrier, 2 porous carrier, 3, 3a, 3b filler, 4 particulate matter, 10 waste water treatment tank, 20 treatment tank body, 21 waste water supply port, 22 discharge port, M microorganism, S void, S1 pore, S2 gap, W drainage

Claims (5)

a porous carrier that is activated carbon;
a filler filled in the voids of the porous carrier, wherein the voids are fine pores in the porous carrier and gaps between the porous carriers;
The filling is soluble in water or decomposed by microorganisms,
Microorganisms are retained in the pores and the gaps from which the filler has flowed out,
A solid carrier for retaining microorganisms used in wastewater treatment, wherein the porous carriers are fixed to each other after the outflow of the filler. 2. The solid carrier according to claim 1, wherein the porous carrier is only activated carbon. 3. The solid carrier according to claim 1, wherein the filler contains particulate matter having a diameter of 1 μm or more. The solid carrier according to any one of claims 1 to 3, characterized in that the filling contains a plurality of substances with different particle sizes. The solid carrier according to any one of claims 1 to 4, wherein the filling contains a plurality of substances with different dissolution rates in water or degradation rates by microorganisms.

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