Microbial carrier

Abstract

To provide a microorganism carrier which does not need to be treated as an industrial waste after used in the treatment of organic waste water and can reduce industrial wastes as well as alleviate environmental load.SOLUTION: A microorganism carrier (carrier 300) of the present invention is characterized by that it is a microorganism carrier packed in a treatment tank 110 for circulation of a fluid which is organic waste water by a trickling filter method, carries an aerobic microorganism, and comprises a biodegradable fiber. The biodegradable fiber is preferably coconut.SELECTED DRAWING: Figure 3

Description

[[Technical Field]]

[0001] The present invention relates to a microorganism carrier that is filled in a treatment tank for circulating a fluid which is organic wastewater in a trickling filter process and supports aerobic microorganisms. [[Background Art]]

[0002] Conventionally, aerobic microorganisms have been used for the treatment of organic wastewater (biological treatment). It is necessary to supply oxygen to activate such aerobic microorganisms. A trickling filter process is one of the methods for supplying oxygen to aerobic microorganisms. In the trickling filter process, water to be treated is sprinkled into a treatment tank, and target substances in the water to be treated are decomposed through a contact reaction between the biological film formed on the surface of a filler (crushed stone, etc.) filled in the treatment tank and the water to be treated.

[0003] In the trickling filter process, when the water to be treated flows down through the treatment tank, it comes into contact with air, so that oxygen dissolves into the water to be treated. For this reason, aeration can be eliminated, making it possible to reduce the equipment cost and the like required for aeration. However, in the trickling filter process, since the time for the water to be treated to flow down through the treatment tank is short, sufficient time cannot be secured for the contact reaction between the biological film on the filler and the water to be treated, and improvement of treatment efficiency has been a problem to be solved.

[0004] As a solution to the above problem, the DHS method (Downflow Hanging Sponge) has been developed in recent years. In the DHS method, water to be treated is sprinkled from the upper part of a reaction tank filled with a sponge carrier, and the water to be treated flows down while contacting microorganisms growing on the sponge carrier, thereby decomposing the target substance. Sufficient time for the contact reaction between the sponge carrier as a filler and the water to be treated can be obtained. Furthermore, while a thin biological film is formed only on the surface of the filler used in the trickling filter method, the sponge carrier used in the DHS method harbors microorganisms also inside. Owing to these features, the DHS method can improve the treatment efficiency of the water to be treated.

[0005] For example, Patent Document 1 discloses a sprinkler-type water purification device using the DHS method. In Patent Document 1, a water-retaining material is filled into a treatment space formed in a hollow tank. This water-retaining material has a cylindrical core material that has shape retention properties and can form ventilation passages on its inside when filled and placed in the treatment space, and a covering carrier layer made of a fibrous material or porous material on which microorganisms can adhere to and grow is formed on the inner and outer surfaces of the cylindrical core material. The ventilation passages of the cylindrical core material are left open to allow ventilation when microorganisms adhere to and grow on the covering carrier layer. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 5739191 [Overview of the project] [Problems that the invention aims to solve]

[0007] The water-retaining body (microbial carrier) of a sprinkler-type water purification system needs to be replaced when its treatment efficiency decreases due to clogging of the sponge carrier after long-term use. In this case, the water-retaining body described in Patent Document 1 uses polyethylene as the tubular core material and polyester as the covering carrier layer, so the water-retaining body after use is disposed of as industrial waste. Thus, although the water-retaining body described in Patent Document 1 can contribute to the treatment of organic wastewater, there is room for further improvement from the perspective of reducing industrial waste and, consequently, environmental protection.

[0008] In view of these problems, the present invention aims to provide a microbial carrier that does not need to be treated as industrial waste after being used to treat organic wastewater, thereby reducing industrial waste and, consequently, the environmental burden. [Means for solving the problem]

[0009] To solve the above problems, a typical configuration of the microbial carrier according to the present invention is a microbial carrier that is filled into a treatment tank for circulating organic wastewater in a spit filter method and carries aerobic microorganisms, characterized in that it is made of biodegradable fibers. Furthermore, the biodegradable fibers are preferably coconut shells.

[0010] The microbial carrier may be in the shape of a brush with the tips of biodegradable fibers facing outwards on its surface. Alternatively, the microbial carrier may be formed by punching out a cylindrical shape from a mat made of biodegradable fibers. Or, the microbial carrier may be formed by punching out a disc shape from a mat made of biodegradable fibers and connecting multiple discs together in a cylindrical shape with biodegradable fasteners. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a microbial carrier that does not need to be treated as industrial waste after being used to treat organic wastewater, thereby reducing industrial waste and, consequently, the environmental burden. [Brief explanation of the drawing]

[0012] [Figure 1] This diagram illustrates a wastewater treatment facility equipped with an organic wastewater treatment system. [Figure 2] Figure 1 is a schematic diagram of the organic wastewater treatment system. [Figure 3] This figure illustrates examples and comparative examples of the carrier according to this embodiment. [Figure 4] This diagram illustrates a coconut fiber mat, which is a biodegradable fiber mat. [Figure 5] This figure illustrates the wastewater treatment performance of the support body in this embodiment and a comparative example. [Modes for carrying out the invention]

[0013] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​shown in these embodiments are merely examples to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustrations.

[0014] (Wastewater treatment facility 200) Figure 1 is an example of a wastewater treatment facility 200 equipped with an organic wastewater treatment system (hereinafter referred to as the treatment system 100). The wastewater treatment facility 200 shown in Figure 1 comprises a sedimentation tank 210, a treatment tank 110, a sand filtration tank 220, and a storage tank 230.

[0015] In the wastewater treatment facility 200, water (organic wastewater) from rivers, etc., is sent to the sedimentation tank 210 by pump 202. In the sedimentation tank 210, the sediment is treated to remove solid matter such as sand. The treated water, after the sediment removal treatment, is sent to the treatment tank 110 of this embodiment by pump 212. In the treatment tank 110, organic matter in the treated water is decomposed by biological treatment using aerobic microorganisms, as described later, and ammonia nitrogen is nitrified by nitrifying bacteria.

[0016] The treated water, after undergoing organic matter decomposition and other treatments, is sent to the sand filtration tank 220 by the water purification pump 140 of the treatment system 100. In the sand filtration tank 220, fine solid matter is removed. The treated water, after the removal of solid matter, is sent to the storage tank 230. The storage tank 230 stores the treated water sent from the sand filtration tank 220 and performs finishing treatments such as adsorption of harmful substances using activated carbon and disinfection. The treated water, after the finishing treatments, is supplied to external water-using facilities by the pump 232.

[0017] (Processing system 100) Figure 2 is a schematic diagram of the organic wastewater treatment system (treatment system 100) in Figure 1. As illustrated in Figure 2, the treatment system 100 of the present embodiment includes a treatment tank 110 that stores a fluid which is organic wastewater. A pump 212 of a sedimentation tank 210 is connected to the treatment tank 110 via a supply pipe 102, and the fluid after sediment removal treatment in the sedimentation tank 210 is supplied via the supply pipe 102. The supply pipe 102 is connected to a nozzle 120 disposed at an upper part of the treatment tank 110, and the fluid supplied to the treatment tank 110 is sprinkled into the treatment tank 110 by the nozzle 120.

[0018] Inside the treatment tank 110 shown in Figure 2, the microorganism carrier of the present embodiment that supports aerobic microorganisms (hereinafter referred to as carrier 300) is accommodated. As described above, the fluid sprinkled from the nozzle 120 contacts the carrier 300 when flowing down in the treatment tank 110. Thereby, a contact reaction with the aerobic microorganisms (not shown) supported by the carrier 300 occurs, and organic substances contained in the fluid are decomposed. The carrier 300 of the present embodiment will be described in detail later.

[0019] The fluid that has passed through the carrier 300 is stored as treated water in a lower part of the treatment tank 110, and is pumped up through a purified water path 142 by a purified water pump 140 at a predetermined timing. A predetermined amount of the pumped-up treated water is delivered to an external facility (not shown) through a delivery path 144, and the remaining part is circulated to the treatment tank 110 through a circulation path 146.

[0020] In the treatment system 100 shown in Figure 2, an ejector 150 that sucks air and forms fine bubbles is disposed in the path of the purified water pump 140, that is, the purified water path 142. Thereby, fine air bubbles (microbubbles) are supplied to the treated water pumped up from the lower part of the treatment tank 110 by the purified water pump 140 when passing through the ejector 150. Then, the treated water that has passed through the ejector 150 is sprinkled into the treatment tank 110 by the nozzle 120 that communicates with a downstream side of the ejector 150.

[0021] Microbubbles have a large specific surface area, so oxygen is easily dissolved in water, which can increase the oxygen concentration of water, and the amount of dissolved oxygen in water supplied with microbubbles increases. Therefore, by sprinkling treated water containing a large amount of dissolved oxygen into the treatment tank 110, oxygen can be efficiently supplied to the entire treatment tank 110. As a result, the aerobic microorganisms supported on the carriers 300 in the entire treatment tank 110 can be activated, making it possible to further improve the treatment efficiency of organic wastewater.

[0022] Furthermore, as described above, by using the ejector 150, air and consequently oxygen can be supplied to the treated water without forced ventilation, that is, while minimizing the amount of air supplied to the treatment tank 110. Therefore, it is possible to avoid the diffusion of odors to the surrounding area that occurs when forced ventilation is performed.

[0023] The treatment system 100 shown in Fig. 2 is further provided with, in a connection path 148 connecting the treatment tank 110 and the purified water pump 140, a water level sensor 160 that detects the water level of treated water stored in the lower part of the treatment tank 110, and a control unit 190 that controls the operation of the purified water pump 140.

[0024] The control unit 190 activates the purified water pump 140 when the water level of the treated water detected by the purified water pump 140 reaches or exceeds a predetermined value. According to this configuration, when a certain amount of treated water is stored in the lower part of the treatment tank 110, part of the treated water pumped up by the purified water pump 140 is delivered to the outside. Therefore, it is possible to suitably prevent the treated water from overflowing the treatment tank 110 when the treatment tank 110 becomes full.

[0025] Furthermore, if the carrier 300 becomes clogged due to the inflow of wastewater containing a large amount of slime (biofilm) or solid matter, the fluid (treated water) sprayed from the nozzle 120 will flow down to the bottom of the treatment tank 110 without being captured by the carrier 300. As a result, the efficiency of the contact reaction between the fluid and the carrier 300 decreases, and the rate at which the water level rises increases. In such cases, the water level sensor 160 operates the water purification pump 140 according to the water level, increasing the number of times the water purification pump 140 is started and increasing the amount of oxygen supplied to the carrier 300. Therefore, it is possible to increase the efficiency of the contact reaction between the fluid and the carrier 300.

[0026] On the other hand, the water level sensor 160 stops the water purification pump 140 when the water level of the treated water falls below a predetermined value. With this configuration, when the amount of treated water inside the treatment tank 110 becomes extremely low, the supply of treated water to external equipment (not shown) is stopped, and the treated water is stored in the treatment tank 110. This suppresses the drying of the support body 300 and prevents the death of aerobic microorganisms supported on the support body 300.

[0027] Furthermore, the treatment system 100 of this embodiment is equipped with a lid 170 that forms the top surface of the treatment tank 110, and the nozzle 120 sprays treated water toward the underside of the lid 170. This allows the treated water to be sprayed more evenly and efficiently over a wider area compared to simply spraying the treated water downwards by the nozzle 120. Therefore, it is possible to promote the activation of aerobic microorganisms and further improve the treatment efficiency of organic wastewater.

[0028] (Carrier 300) As described above, the carrier 300 in this embodiment is filled into a treatment tank that circulates a fluid which is organic wastewater in the drip filter method and carries aerobic microorganisms. A feature of this embodiment is that biodegradable fibers are used for the carrier 300. With this configuration, the carrier 300 itself is slowly biodegraded, so the amount of waste can be reduced. For example, the decomposition rate is such that while organic substances contained in the treated water are decomposed in a cycle of several days, the carrier 300 is decomposed in about a year. Furthermore, the carrier 300 can be reused as fertilizer after use.

[0029] Therefore, according to the carrier 300 of this embodiment, there is no need to treat it as industrial waste after using it to treat organic wastewater, making it possible to reduce industrial waste and, consequently, the environmental burden. When the carrier 300 is biodegraded and reduced in volume in the treatment tank 110, additional carrier 300 can be added.

[0030] Furthermore, in conventional DHS methods, foam materials used as water-retaining bodies tended to accumulate solid matter exceeding the diameter of the micropores (e.g., 0.3-2.0 mm) on the surface, leading to clogging and increased slime buildup, which often resulted in surface flow. In contrast, by using fibrous material instead of foam material, solid matter can be incorporated into the interior, allowing for contact with microorganisms, thus suppressing surface flow. In addition, using fibrous material promotes oxygen supply to the interior of the carrier 300, improving the efficiency of decomposition of organic matter in organic wastewater by aerobic microorganisms.

[0031] Coconut husks are a suitable biodegradable fiber for the above-mentioned material. Because coconut husks are widely available, they are inexpensive and readily available. Furthermore, coconut husks possess a certain degree of rigidity, offering the advantage of being less prone to deformation even when stacked vertically (for example, to a height of 1 meter).

[0032] Furthermore, the coconut fiber carrier 300, in addition to its function of decomposing organic matter contained in organic wastewater by supported microorganisms as in conventional methods, has high water permeability, making it possible to filter and capture suspended solids in organic wastewater. It should be noted that the biodegradable fiber is not limited to coconut fiber; other materials such as wood, sugarcane, and rice husks can also be used.

[0033] Furthermore, the carrier 300 is preferably in the shape of a brush with the tips of the biodegradable fibers facing outwards. "The tips of the fibers facing outwards" means that the cut surface of the fibers is on the surface of the carrier 300. As a result, even if slime forms on the surface of the carrier 300, the tips (ends) of the biodegradable fibers will protrude from the slime. Therefore, a sufficient contact area between organic wastewater and aerobic microorganisms can be ensured, and treatment efficiency can be suitably maintained.

[0034] Figure 3 illustrates examples and comparative examples of the carrier 300 according to this embodiment. Figure 3(a) is a perspective view of the carrier 300a of Example 1. Figure 3(b) is a perspective view of the carrier 300b of Example 2. Figure 3(c) is a perspective view of the carrier 300c of Example 3. Figure 3(d) is a perspective view of the comparative example carrier 30.

[0035] The carrier 300a of Example 1 shown in Figure 3(a) is a cylinder made of biodegradable fibers. The carrier 300b of Example 2 shown in Figure 3(b) is constructed by stacking a plurality of discs 310 made of biodegradable fibers in a cylindrical shape and connecting the plurality of discs 310 with biodegradable fasteners 320.

[0036] The discs 310 of the carrier 300a in Example 1 and the carrier 300b in Example 2 may be formed by punching out a mat of biodegradable fibers using a tool such as a cutter (not shown). As a result, the surfaces of the carriers 300a and 300b (more precisely, the discs 310) are left unfinished, so that the tips of the biodegradable fibers face outwards, creating a brush-like surface, and the above-mentioned effects can be obtained without any special surface processing.

[0037] Specifically, the support body 300a of Example 1 can be manufactured in a single punching (process) by using a thick mat. The disc 310 of the support body 300b of Example 2 can be easily punched out by using a thin mat.

[0038] The carrier 300c of Example 3 shown in Figure 3(c) is constructed by creating a cylinder 330 by spirally winding a mat of biodegradable fibers, and fastening the outer surface of the cylinder 330 with a biodegradable band 340. The same effects as described above can be obtained with this configuration as well. However, in the carrier 300c of Example 3, the proportion of fiber tips facing the surface of the carrier is small.

[0039] Figure 4 illustrates a coconut fiber mat, which is a biodegradable fiber mat. The coconut fiber mat shown in Figure 4 is formed by shaping rope-like coconut fibers into a sheet using needle punching. The coconut fiber mat shown in Figure 4 can be suitably used as the carrier 300a in Example 1, the carrier 300b in Example 2, and the carrier 300c in Example 3 described above.

[0040] The comparative example carrier 30 shown in Figure 3(d) comprises a porous body 32 that supports aerobic microorganisms and absorbs water, and a frame 34 that maintains the shape of the porous body 32. The porous body 32 is made of a polymer material having countless minute pores, such as a sponge, and the frame 34 is made of a highly rigid synthetic resin material.

[0041] Figure 5 illustrates the wastewater treatment performance of the support 300 of this embodiment and a comparative example. Figure 5(a) illustrates the change in BOD (biochemical oxygen demand) of the influent and treated water. Figure 5(b) illustrates the change in SS (suspended solids) of the influent and treated water. Figure 5(c) illustrates the change in COD-solube (soluble chemical oxygen demand) of the influent and treated water.

[0042] In Figures 5(a)-(c), the carrier of Example C is used as 300 in this embodiment. The inflow water is sewage, and the treated water is water that has passed through a treatment tank 110 filled with the carrier of Example C or the carrier 30 of the comparative example.

[0043] Referring to Figure 5(a), for example, when the influent water BOD is 3000 mg / L, the treated water BOD is 400 mg / L when using the carrier of Example C, and 800 mg / L when using the comparative example carrier 30. From this, it can be seen that by using coconut shell, a biodegradable fiber, as in this embodiment, the amount of BOD, i.e., the amount of pollutants contained in the treated water, can be halved compared to the conventional sponge carrier 30.

[0044] Referring to Figure 5(b), for example, when the influent water SS is 4000 mg / L, the treated water SS is 350 mg / L when the carrier of Example C is used, and 500 mg / L when the comparative example carrier 30 is used. From this, it can be seen that by using biodegradable fibers (coconut shells) as in this embodiment instead of conventional sponges, solid matter contained in the treated water can be suitably captured, and the turbidity of the treated water can be reduced by 30% compared to conventional methods. Furthermore, this also means that while conventional carriers used in DHS are generally used at low concentrations of 200 mg / L or less, the carrier of Example C can adequately handle shock loads (when wastewater containing abnormally high concentrations of solids or dissolved substances flows in).

[0045] Referring to Figure 5(c), it can be seen that, when the COD-solube of the influent water is the same, the COD-solube of the treated water that has passed through the support of Example C tends to be lower than that of the support of Comparative Example 30. From this, it can be seen that the support 300 made of biodegradable coconut fiber, as in this embodiment, can treat pollutants dissolved in the influent water more efficiently than the conventional sponge support 30.

[0046] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these examples. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention. [Industrial applicability]

[0047] The present invention can be used as a microbial carrier that is filled into a treatment tank for circulating organic wastewater in a spit filter system and carries aerobic microorganisms. [Explanation of Symbols]

[0048] 30...Carrier, 100...Processing system, 102...Supply pipe, 110...Processing tank, 120...Nozzle, 140...Water purification pump, 142...Water purification route, 144...Discharge route, 146...Circulation route, 148...Connecting route, 150...Ejector, 160...Water level sensor, 190...Control unit, 200...Wastewater treatment equipment, 202...Pump, 210...Sedimentation tank, 212...Pump, 220...Overheating tank, 230...Storage tank, 232...Pump, 300...Carrier, 300a...Carrier, 300b...Carrier, 300c...Carrier, 310...Disc, 320...Fastener, 330...Cylinder, 340...Band

Claims

1. A microbial carrier that is filled into a treatment tank for circulating organic wastewater in a trickling filter method and carries aerobic microorganisms, It is formed by punching out cylindrical shapes from a mat made of biodegradable fibers. A microbial carrier characterized by having a brush-like shape with the tips of the biodegradable fibers facing outwards on its surface.

2. A microbial carrier that is filled into a treatment tank for circulating organic wastewater in a trickling filter method and carries aerobic microorganisms, It is formed by punching out disc shapes from mats made of biodegradable fibers and connecting multiple of them together in a cylindrical shape with biodegradable fasteners. A microbial carrier characterized by having a brush-like shape with the tips of the biodegradable fibers facing outwards on its surface.

3. The microbial carrier according to claim 1 or 2, characterized in that the biodegradable fiber is coconut shell.

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