Water purification materials and water purification treatment equipment

Abstract

The objective is to create a water purification material that uses carbon fiber to perform water purification treatment using aerobic microorganisms, is easy to maintain (such as replacing or replenishing microorganisms), can operate water treatment facilities continuously and efficiently, and is a compact water purification system that can be installed in a relatively small area by combining a soil-based water purification tank and a carbon fiber-based water purification tank. [Solution] The water purification material A is a molded body of carbon fiber composite ceramics which is a water-permeable honeycomb structure, and a part or the entire length of the carbon fibers 3 is exposed along the inner surface 1a of the holes 1 of the molded body that hold the carbon fibers 3 in a dispersed state or along the surface 2 of the molded body.

Description

Technical Field

[0003]

[0001] This invention relates to a water purification material that utilizes the purification action of microorganisms and a water purification treatment apparatus using the same.

Background Art

[0002] Generally, when purifying water by removing organic and inorganic pollutants from industrial wastewater, domestic wastewater, or river water, activated sludge treatment, anaerobic treatment, and aerobic treatment are performed successively so that the purified water has a BOD of 20 to 10 mg / L or less. In addition, it is well known that in order to perform a higher level of purification, purification is carried out using microorganisms contained in soil. A water purification treatment apparatus is known in which soil formed into brick shapes is arranged in multiple stages in a porous water-permeable layer such as pumice so that water purification treatment can be performed efficiently (Patent Document 1).

[0003] It is also well known that sterilization and deodorization treatment by the oxidation action of ozone is performed in combination with the purification treatment by microorganisms. For example, air is supplied to the water to be treated by aeration, and ozone is supplied for sterilization and deodorization treatment. Then, in order to convert the ozone remaining in the water to be treated into safe oxygen, it is known to add Bacillus subtilis (Patent Document 2).

[0004] In a conventional water purification treatment apparatus E using a soil treatment tank 18 shown in FIG. 7, the water to be treated with increased dissolved oxygen in an aeration tank 21 after passing through a sedimentation separation tank 20 from a raw water tank 19 is sprinkled in a shower shape by a sprinkler from a multi-branch pipe installed directly above the soil treatment tank 18. Microorganisms such as natural aerobic bacteria growing in the soil S absorb and decompose organic and inorganic substances, and the filtered treated water W2 is collected by a non-woven fabric 22 laid on the lower surface of the soil treatment tank 18 and transferred to a disinfection tank 23, where it is disinfected with ozone, ultraviolet rays, chlorine, etc. so that it can be used as intermediate water.

[0005] Incidentally, water purification materials using carbon fibers are known, in which long carbon fibers cut to a certain length are tied together at one end to form a brush-like or bristly tuft (also called a fringe), and the free end is opened in water to allow microorganisms in the water to attach to the carbon fibers and decompose organic matter, etc. (Patent Document 3).

[0006] A water purification apparatus is also known in which such fringes are placed in a treatment tank so as to unfurl in water, and water purification is performed by microorganisms. In addition, granular porous ceramic sintered material is loaded into a treatment tank downstream of this treatment tank, and water purification is further performed by microorganisms that settle in the pores of the material. (Patent Document 4) [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2003-340477 [Patent Document 2] Japanese Patent Publication No. 2022-6372 [Patent Document 3] International Publication No. 2010 / 35800 [Patent Document 4] Japanese Patent Publication No. 2013-34960 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, in order to perform water purification treatment using the soil described in Patent Document 1 and Figure 7, it is necessary to install a soil treatment tank with a large installation area and an open top.

[0009] Furthermore, if purification treatment is continued for a long period using a soil treatment layer, the number and activity of Bacillus bacteria necessary for water purification decrease due to an increase in the number of general bacteria, and the water purification capacity gradually declines.

[0010] Therefore, the usual procedure involves temporarily stopping the supply of water to be treated to deplete the water and nutrients necessary for bacterial growth, thus preserving only Bacillus bacteria that form spores as durable cells. When the water to be treated is restored, the growth of Bacillus bacteria is resumed, making this species dominant in the soil treatment tank.

[0011] However, such water outages need to be carried out over a long period of about a month, and in order to operate the water purification treatment equipment continuously throughout the entire treatment facility, it is necessary to keep the water supply to about 1 / 2 to 1 / 4 of the soil treatment tank equipment shut off at all times. Therefore, as mentioned above, the installation area of ​​the soil treatment tank in the water purification system always requires a non-movable area of ​​about 1 / 2 to 1 / 4, which presents a problem in that it is not possible to sufficiently increase the treatment efficiency.

[0012] Furthermore, in the water purification devices described in Patent Document 3 or Patent Document 4, which purify aerated water by attaching microorganisms such as aerobic bacteria to fringe-shaped carbon fibers, it is necessary to periodically replace or replenish the microorganisms during water shutoff or washing treatments, which necessitates complicated maintenance work.

[0013] To clean long carbon fibers bundled in a fringe shape, it is necessary to aerate them vigorously with high air pressure in the treatment tank to separate microorganisms from the water purification material. However, various types of microorganisms, such as aerobic bacteria, adhere to the long fibers of the fringe-shaped water purification material, which are about 10 to 30 cm long, forming a biofilm. Removing this soft, sticky biofilm from between the fibers is not easy. Thus, with conventional water purification systems, it has been difficult to simplify maintenance work and reduce the installation area while maintaining the required treatment capacity.

[0014] Therefore, the objective of this invention is to solve the problems of conventional water purification treatment described above, to provide a water purification material that uses carbon fiber to perform water purification treatment using aerobic microorganisms, and that is easy to maintain, such as replacing or replenishing microorganisms, and to provide a water purification treatment device that can operate continuously and efficiently, and furthermore, to provide a compact water purification treatment device that can be installed in a relatively small area by having both a soil-based water purification tank and a carbon fiber-based water purification tank. [Means for solving the problem]

[0015] To solve the above problems, this invention provides a water purification material made of a molded body having permeable channels consisting of holes or grooves, using carbon fiber composite ceramics in which carbon fibers are dispersed in ceramics as the molding material, and exposing the carbon fibers on the surface of the molded body or in the permeable channels.

[0016] As described above, the water purification material of this invention has a water channel consisting of holes or grooves in a molded body of carbon fiber composite ceramics that comes into contact with the water to be treated, in which a portion or the entire length of short fibrous carbon fibers held in a dispersed state are exposed.

[0017] Therefore, microorganisms contained in the treated water attach to the carbon fibers they come into contact with, grow and multiply, and through the assimilation capabilities of the microorganisms, organic and inorganic substances in the treated water are decomposed, some of which are absorbed as nutrients for the microorganisms, thus purifying the treated water.

[0018] The carbon fibers are dispersed and held in the ceramics, either partially or entirely, with at least a portion of the fibers embedded and partially fixed and exposed along the surface of the ceramic molded body. Therefore, the carbon fibers are dispersed rather than densely packed together, and microorganisms attach to each fiber and grow widely dispersed on the surface of the ceramic molded body or in the permeable channels, resulting in high contact efficiency between the treated water and the microorganisms.

[0019] In addition, when general bacteria other than useful bacteria such as Bacillus bacteria increase and the number and activity of fungi useful for water purification treatment decrease, sterilization treatment can be performed relatively easily and in a short time by adding a component with sterilization or bactericidal power such as ozone to the water to be treated.

[0020] After the sterilization treatment, useful bacteria such as Bacillus bacteria are added to the water to be treated, and the useful bacteria are grown so that they quickly become dominant on the surface of the molded body or the carbon fibers exposed in the water passage.

[0021] In this way, when using a molded body with carbon fiber composite ceramics as the molding material, maintenance work for replacing a microbial group with a reduced purification treatment ability with a microbial group with a high purification ability can be efficiently performed.

[0022] Therefore, there is no need to keep 1 / 2 to 1 / 4 of the soil treatment tank out of operation for a long time by water cut-off treatment as in a conventional water purification treatment device, the operating efficiency of the water purification treatment device can be increased, its installation area can be reduced, and the water purification treatment device can be made compact.

[0023] The molded body with carbon fiber composite ceramics as the molding material is preferably a sintered body having communicating pores of the carbon fiber composite ceramics so as to increase the efficiency of the water to be treated coming into contact with and passing through the carbon fibers as much as possible.

[0024] In addition, cement can be used as the ceramics used for the carbon fiber composite ceramics, and the carbon fiber composite ceramics may be carbon fiber composite cement in which carbon fibers are mixed with cement. Such carbon fiber composite ceramics can form water-permeable holes, grooves, gaps, etc. on the surface or inside of the molded body by molding.

[0025] As a molded body of any shape made of carbon fiber composite ceramics, a honeycomb structure body provided with cells serving as water passages, or grooves and irregularities are formed on the surface of a molded body of any shape to increase the water permeability of a single body or an aggregate and to make it difficult for the water to be treated to be clogged is preferable.

[0026] Furthermore, in order to improve water permeability, if the water purification material consists of an aggregate of the above-mentioned molded bodies, the aggregate may be housed in a water-permeable container (case), or it may be directly loaded into part or all of the treatment tank and assembled therein. In either case, the shape and size of the molded bodies are adjusted so that water-permeable gaps are formed between adjacent surfaces of the individual aggregates.

[0027] To enable efficient water purification and to facilitate maintenance such as replenishing microorganisms, the water purification material is placed in the purification tank so that the water to be treated flows down the inner surface of the permeable channel or the surface of the molded body.

[0028] By incorporating the water purification material into the treatment tank in this way, a compact water purification system is created that combines a soil-based water purification tank and a carbon fiber-based water purification tank, while requiring a smaller installation area than if both tanks were placed side by side.

[0029] In particular, because the treatment tank is located downstream of the treatment tank equipped with a soil layer, in addition to the biodegradation treatment of the water to be treated by the soil layer installed over the area necessary for treatment, microorganisms from the soil can be supplied to the carbon fiber composite ceramics by utilizing the water flow downstream.

[0030] Furthermore, the treated water containing chemicals and microorganisms can be efficiently passed through the carbon fibers for disinfection and replenishment of microorganisms. This increases the processing efficiency of a continuously operating water purification system, resulting in a water purification system that can replace beneficial microorganisms at the appropriate timing and in a short period of time. [Effects of the Invention]

[0031] The water purification material of this invention has the advantage that, because the carbon fibers, which are dispersed in carbon fiber composite ceramics, are exposed on the inner surface of the permeable channel of the molded body that comes into contact with the water to be treated, or on the surface of the molded body, water purification treatment using aerobic microorganisms can be efficiently carried out using carbon fibers, and maintenance such as replacement and replenishment of microorganisms can be easily performed.

[0032] Furthermore, by installing such water purification materials on the inner surface of the permeable channel through which the treated water flows or on the surface of the molded body, a water purification treatment device can be created that can continuously and efficiently treat water. It also has the advantage of being a compact water purification treatment device with a smaller installation area than having both a soil-based water purification tank and a carbon fiber-based water purification tank placed side by side. [Brief explanation of the drawing]

[0033] [Figure 1] Perspective view of the water purification material according to the first embodiment. [Figure 2] A perspective view showing a magnified portion of Figure 1. [Figure 3] Perspective view of the water purification material according to the second embodiment. [Figure 4] Perspective view of the water purification material according to the third embodiment. [Figure 5] Cross-sectional view of the main part of the water purification treatment apparatus of the embodiment. [Figure 6] Plan view of the main part of the water purification treatment apparatus of the embodiment [Figure 7] Cross-sectional view of a conventional water purification system. [Modes for carrying out the invention]

[0034] Embodiments of this invention will be described below with reference to the accompanying drawings. As shown in Figures 1 and 2, the water purification material A of the first embodiment consists of a molded body of carbon fiber composite ceramics which is a water-permeable honeycomb structure, and the carbon fibers 3 are exposed on the inner surface 1a of the holes 1 which are water channels in the molded body that hold the carbon fibers 3 in a dispersed state, or on the surface 2 of the molded body.

[0035] When viewed microscopically in this exposed state, the carbon fiber 3 has a portion of its fibers, or its entire length, exposed along the surface 2 of the molded body, along the inner surface 1a or surface 2. The carbon fiber 3 is embedded in the surface 2 of the molded body to a depth of about half the fiber diameter, and about half the fiber diameter of the fiber surface is kept exposed on the surface 2 of the molded body.

[0036] The carbon fiber composite ceramic molded body of the first embodiment is prepared by molding a slurry made by compounding short carbon fibers with a well-known ceramic material that has excellent water resistance, drying it, and then firing it.

[0037] Furthermore, while these ceramic materials are designed to avoid compounds and additives that chemically damage carbon fibers, depending on the durability required for practical use, the types of raw materials such as ceramics and the particle sizes of their powders are not particularly limited and can be used.

[0038] Specifically, this includes ceramic materials used in unglazed pottery, as well as muddy materials mainly composed of feldspar and quartz, which are discharged when refining feldspar for tiles and glass from weathered granite. Examples of ceramic materials include silicon carbide-based ceramics and aluminum oxide-based ceramics, and commercially available porous ceramic materials may also be used for molding and firing.

[0039] Furthermore, the carbon fiber composite ceramics described above may be sintered bodies having interconnected pores. To produce a sintered body, it is preferable to mix a porosity agent (also known as a pore-forming agent) into a slurry containing powdered or particulate ceramic material and then fire and sinter it.

[0040] Examples of porosity agents include resin particles that disappear at the firing temperature of ceramics, and well-known organic or inorganic porosity agents such as carbonates and hydroxides that generate carbon dioxide or water vapor when heated. The proportion of these agents is appropriately selected according to the required porosity of the molded body.

[0041] Carbon fiber composite ceramics can also be manufactured using a slurry in which crushed stone or other aggregates with a major axis of about 5 to 30 mm are mixed in an appropriate amount with ceramics such as cement, so that the molded body has many permeable, interconnected pores.

[0042] The carbon fibers used in this invention are short fibers, and may be either PAN-based or pitch-based. It is preferable to selectively use fibers with short lengths so that they can be dispersed and mixed as uniformly as possible in the slurry containing the ceramic material.

[0043] The fiber length of such carbon fibers is not related to improving the strength of the molded body, but from the viewpoint of increasing the efficiency of contact with microorganisms, it is sufficient if it is, for example, 10 mm or less or 5 mm or less, and it has been found that using carbon fibers of 3 mm or less (or less), and more preferably 2 mm or less, results in high microbial contact efficiency and adhesion efficiency.

[0044] Furthermore, the appropriate ratio of carbon fibers to ceramics can be selected depending on the type of microorganism suitable for fixation to the carbon fiber surface, the shape of the molded body, or the form of the treatment tank. For example, favorable results have been obtained by incorporating approximately 10-30% by mass or 10-20% by mass into the ceramic slurry.

[0045] In addition, the water purification material made of the molded body of the first embodiment shown in Figures 1 and 2 is illustrated as a square prism-shaped honeycomb structure having a hexagonal cylindrical partition wall and a square cylindrical outer wall. However, the molded body may have an external shape other than such a honeycomb structure, such as a spherical, elliptical, polyhedral, or other known block-shaped or granular shape, or an irregularly shaped lump or granular molded body such as a natural material.

[0046] The microorganisms in the treated water in this invention are bacteria that exist in the water treatment environment and spontaneously occur in the treated water, as well as protozoa and metazoans that feed on bacteria, fungi, or algae. It is preferable that the microorganisms be fungi with a high organic matter digestion rate, and spore-forming bacteria such as Bacillus that survive by forming spores even after sterilization treatment are particularly suitable species. Typically, Bacillus subtilis and other specific microorganisms are predominantly present.

[0047] Furthermore, Bacillus subtilis is a microbial material that has high water purification efficiency, is resistant to ozone sterilization by forming spores, and is readily available. By adding it to the water to be treated as needed, it promotes the generational change of microorganisms, thereby increasing the efficiency of water purification.

[0048] In the first embodiment of the water purification material A, microorganisms in the water to be treated attach to and proliferate on carbon fibers dispersed on the surface of the molded body or on the inner surface 1a of the pores 1 formed in the molded body. However, when a disinfecting (sterilizing) component such as ozone is added to the water to be treated and disinfection treatment is performed, their physiological activity decreases, their adhesive force weakens, and they detach from the surface of the carbon fibers due to the flow of the water to be treated. Therefore, by regularly replenishing highly active microorganisms useful for purified water after disinfection, water purification system A can stably maintain a high purification capacity over time.

[0049] Furthermore, as shown in Figure 3, the water purification material B, which is the second embodiment of this invention, consists of a large number of aggregates of individual spherical molded bodies 5 made of sintered bodies having interconnected pores 4. These aggregates are housed in a water-permeable case such as a metal (steel wire) mesh cage 6, and water-permeable gaps are provided between the surfaces of adjacent spherical molded bodies 5. In addition, since each individual spherical molded body 5 is a porous fired body and has interconnected pores 4, each individual body also possesses water permeability.

[0050] The spherical molded body 5 shown in the illustration has carbon fibers 3 exposed on its surface and inside the connecting pores 4, and microorganisms in the treated water attach to the carbon fibers 3 and grow.

[0051] During the water purification process, the water flow of the water to be treated penetrates the surface of the spherical molded body 5 and the inside of the connecting pores 4, and passes through the microorganisms that have attached to and proliferated on the carbon fibers 3, thereby maintaining a stable state of high purification capacity over time, similar to the first embodiment.

[0052] As shown in Figure 4, the third embodiment of the present invention, the water purification material C, contains aggregate 7 made of crushed stone with a particle size of about 5 to 30 mm, and carbon fiber composite ceramics containing short carbon fibers 3, which are carbon fiber composite cement, and a square or rectangular plate-shaped molded body 8 is formed using this as a binder. Two of these molded bodies 8 are combined as a single unit to form an aggregate called the water purification material C, and water-permeable gaps are provided between adjacent surfaces of the single units.

[0053] The water-permeable gaps in the water purification material C are formed when two sets of such individual molded bodies 8 are placed adjacent to each other, with the grooves 9 and ridges 10 being lower in height than the side edges of one side of the molded body 8 being recessed grooves 9 and ridges 10 being lower in height along the grooves 9.

[0054] In the third embodiment, as the ceramic, a well-known cement that can harden without heating and is water-resistant can be used, such as Portland cement or mixed cement containing limestone, clay, gypsum, or clinker.

[0055] The aggregate is not particularly limited, and any well-known aggregate used in concrete can be used. However, it is preferable to use porous zeolite or glass foam material (SuperSol), as aggregates with a high surface area ratio will also function effectively as a substrate for mushroom growth.

[0056] Furthermore, the binder used for the aggregate is not limited to cement; epoxy binders for permeable pavements or inorganic binders may be used in combination or alone. Moreover, it is preferable to minimize the amount of binder used in order to maximize the surface exposure of the mixed carbon fibers. For example, by blending cement or a binder other than cement in an amount of 5 to 12 parts by mass, preferably 6 to 8 parts by mass, per 100 parts by mass of aggregate, suitable conditions for stable bonding strength and carbon fiber exposure can be ensured.

[0057] As shown in Figures 5 and 6, the water purification treatment apparatus D, which is an embodiment of this invention, is installed as a water purification facility according to its treatment capacity, and the water purification material A of the first embodiment is installed in the purification treatment tank 11 so that the water to be treated W flows down along the inner surface 1a of the hole 1.

[0058] Raw water to be treated, discharged from facilities such as factories and hospitals, undergoes preliminary treatment to separate sludge, and then passes through a flow rate adjustment tank (not shown) and multiple aeration tanks before being stored in an ozone oxidation tank 12, which also serves to adjust the flow rate.

[0059] In the ozone oxidation tank 12, wastewater that has been treated in advance from a biological treatment facility to meet the wastewater treatment standard of BOD 20 mg / L or less can be used as raw water and subjected to advanced treatment using the water purification treatment device D, which is an embodiment of this invention.

[0060] In the ozone treatment tank 12 (the leftmost tank shown in Figure 5), ozone-containing oxygen is mixed using a circulation pump (not shown) and a Venturi tube connected to the pump. By mixing ozone with the wastewater circulated by the pump and connecting a microbubble generator to the circulation piping, the ozone-containing oxygen can efficiently dissolve ozone into the target water, and insoluble ozone-containing oxygen is not released into the atmosphere. The ozone treatment tank 12 can respond appropriately to wastewater purification and soil sterilization depending on the ozone generation intensity.

[0061] The ozone generation intensity can be easily adjusted by controlling the current or voltage. Furthermore, when ozone treatment is performed before wastewater treatment, exposure to 100 μg / L of ozonated water for 10 seconds will kill most bacteria and prevent the leakage of harmful bacteria.

[0062] In the next treatment tank 11, the water to be treated W, supplied from a water pump (not shown), is sent to a multi-branch pipe 13 for sprinkler watering.

[0063] Directly beneath it is a soil layer 14 about 100-200 cm deep, and further below that, a nonwoven fabric 15 is laid to prevent soil runoff. Below the nonwoven fabric 15, the water purification material A of the first embodiment is placed with the holes 1 facing vertically.

[0064] Multiple adjacent water purification materials A are laid so as not to leave any gaps, and the lower ends of these water purification materials A are supported at the lowest end of the purification tank 11 by a grid-like frame 16.

[0065] Furthermore, a space is provided at the bottom of the septic tank 11 where the treated water W1 that has passed through the holes 1 of the water purification material A is temporarily stored. The stored treated water W1 is then pumped up and finally transferred to the water collection and disinfection tank 17 so that it can be used as purified water.

[0066] In the water purification treatment apparatus D of the above embodiment, a honeycomb-structured water purification material A is placed downstream of the soil layer 14 in the purification treatment tank 11. By placing the water purification material A in this manner, in addition to the biodegradation treatment in the soil layer 14 installed over the area required for purification, the water flow of the water to be treated W flowing downstream is used to constantly replenish microorganisms by allowing microorganisms present in the soil layer 14, as well as commercially available Bacillus subtilis newly added to the soil layer 14, to adhere to the carbon fibers exposed on the inner surface 1a of the pores 1 made of carbon fiber composite ceramics.

[0067] This increases the water purification efficiency of the water purification treatment device D, and after sterilization treatment with ozone at the appropriate time, it becomes possible to add separately obtained microorganisms to the soil layer 14, etc., allowing for periodic replacement and replenishment of microorganisms. This actively improves the water purification capacity by microorganisms, thereby stably increasing the treatment efficiency of water purification over time. [Explanation of Symbols]

[0068] A, B, C Water purification materials D, E Water purification treatment equipment W: Water to be treated W1, W2 treated water S soil 1 hole 1a Inner Self 2 surface 3 Carbon Fiber 4 interconnected vents 5 Spherical molded body 6 mesh basket 7 Aggregates 8 Molded body 9 grooves 10 Ridge 11. Septic tank 12 Ozone Oxidation Tank 13 Multi-branch pipe 14. Soil layer 15, 22 Nonwoven fabric 16 Frame 17 Water collection / disinfection tank 18. Soil treatment tank 19 Raw water tank 20 Sedimentation and decomposition tank 21 Aeration tank 23 Disinfection tank

Claims

1. A water purification material comprising a molded body having permeable channels consisting of holes or grooves, with carbon fibers exposed on the surface of the molded body or in the permeable channels, using carbon fiber composite ceramics in which carbon fibers are dispersed in ceramics as the molding material.

2. The water purification material according to claim 1, wherein the carbon fiber composite ceramic is a carbon fiber composite ceramic made of a sintered body having interconnected pores.

3. The water purification material according to claim 1, wherein the carbon fiber composite ceramic is carbon fiber composite cement.

4. The water purification material according to claim 3, wherein the molded body is a molded body containing aggregate.

5. The water purification material according to any one of claims 1 to 4, wherein the molded body is a molded body made of a honeycomb structure.

6. A water purification material according to any one of claims 1 to 4, comprising an aggregate of the above-mentioned molded bodies, wherein water-permeable gaps are provided between adjacent surfaces of the individual bodies.

7. A water purification apparatus comprising a water purification material according to any one of claims 1 to 4, placed in a purification tank such that the water to be treated flows down the permeable channel or the surface of the molded body.

8. A water purification apparatus comprising the water purification material described in claim 5, arranged in a purification tank such that the water to be treated flows down the permeable channel or the surface of the molded body.

9. A water purification apparatus comprising the water purification material described in claim 6, arranged in a purification tank such that the water to be treated flows down the permeable channel or the surface of the molded body.

10. A water purification apparatus according to claim 7, wherein the purification tank is located downstream of the purification tank having a soil layer.

11. A water purification apparatus according to claim 8, wherein the purification tank is located downstream of the purification tank having a soil layer.

12. A water purification apparatus comprising a purification tank according to claim 9, wherein the purification tank is located downstream of the purification tank having a soil layer.

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