Organic wastewater treatment system

Abstract

[Problem] The purpose of the present invention is to provide an organic waste water treatment system capable of efficiently supplying oxygen to the entirety of a treatment tank, which is a treatment space, and capable of treating organic waste water with further improved efficiency. [Solution] The configuration of the organic waste water treatment system (treatment system 100) according to the present invention is characterized by comprising: a treatment tank 110 that retains a fluid that is organic waste water; a carrier 130 that is housed in the treatment tank 110, and that carries aerobic microorganisms; a water purification pump 140 that pumps up to-be-treated water retained in a lower portion of the treatment tank 110 such that the water is circulated in the treatment tank 110 and is sent to the outside; an ejector 150 that is disposed in a path (water purification path 142) of the water purification pump 140, and generates fine bubbles; and a nozzle 120 that is connected to the downstream side of the ejector 150, and sprays, in the tank 110, the water to be treated.

Description

[Technical Field]

[0001] The present invention relates to a wastewater treatment system for treating organic wastewater. [Background technology]

[0002] Aerobic microorganisms have traditionally been used to treat organic wastewater (biological treatment). To activate these aerobic microorganisms, oxygen must be supplied. One method of supplying oxygen to aerobic microorganisms is the trickling filter method. In this method, the water to be treated is sprinkled into a treatment tank, and the target substances in the water are decomposed by a contact reaction between the water and a biofilm formed on the surface of filler material (such as crushed stone) filled in the treatment tank.

[0003] In the trickling filter method, oxygen dissolves in the water as it comes into contact with air as it flows down through the treatment tank. This eliminates the need for aeration, making it possible to reduce the cost of equipment required for aeration. However, in the trickling filter method, the time it takes for the water to flow down through the treatment tank is short, which does not allow enough time for the biofilm on the filler material to come into contact with the water, making it difficult to improve treatment efficiency.

[0004] The DHS (Downflow Hanging Sponge) method has been developed in recent years as a solution to the above-mentioned problems. In the DHS method, the water to be treated is sprayed from the top of a reaction tank filled with sponge carriers, and the water flows down while coming into contact with the microorganisms growing on the sponge carriers, thereby decomposing the target substances. This allows ample time for the sponge carrier filler and the water to be treated to come into contact and react. Furthermore, while a thin biofilm forms only on the surface of the filler used in the trickling filter method, the sponge carrier used in the DHS method has microorganisms living inside as well. As a result, the DHS method can improve the treatment efficiency of the water to be treated.

[0005] For example, Patent Document 1 discloses a sprinkler-type purification device using the DHS method. In Patent Document 1, a treatment space formed inside a hollow tank is filled with a water-retaining body as a filler. This water-retaining body has a cylindrical core material with shape retention that allows an air passage to be formed inside when filled and arranged inside the treatment space, and a coated carrier layer made of a fibrous material or porous material that allows microorganisms to attach and grow is formed on the inner and outer surfaces of the cylindrical core material. The air passage of the cylindrical core material is open and breathable when microorganisms are attached and grown on the coated carrier layer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5739191 Summary of the Invention [Problem to be solved by the invention]

[0007] The sprinkler-type purification device of Patent Document 1 is provided with an air supply pipe that supplies oxygen-containing gas into the treatment space in parallel with the treated water. According to Patent Document 1, supplying oxygen-containing gas to the water-retaining body promotes aerobic decomposition of the treated water by microorganisms. Furthermore, by forming a space in the water-retaining body with an air passage, the oxygen-containing gas circulating in the space is efficiently supplied to the microorganisms, achieving high decomposition efficiency of the treated water.

[0008] However, in the configuration in which oxygen-containing gas is simply supplied into a hollow tank as in Patent Document 1, although it is thought that the oxygen-containing gas is efficiently supplied to the microorganisms in the coated carrier layer near the connection part of the air supply pipe in the hollow tank, it is difficult to spread the oxygen-containing gas throughout the entire treatment space in the hollow tank. Therefore, there is room for further improvement in the technology of Patent Document 1.

[0009] In view of these problems, the present invention aims to provide an organic wastewater treatment system that can efficiently supply oxygen to the entire treatment tank, which serves as the treatment space, and that can further improve the treatment efficiency of organic wastewater. [Means for solving the problem]

[0010] In order to solve the above problems, a typical configuration of an organic wastewater treatment system according to the present invention is characterized by comprising a treatment tank for storing a fluid that is organic wastewater, a carrier housed in the treatment tank and carrying aerobic microorganisms, a purified water pump that pumps the treated water stored in the lower part of the treatment tank and circulates it back into the treatment tank and sends it out, an ejector that is placed in the path of the purified water pump and generates fine bubbles, and a nozzle that is connected to the downstream side of the ejector and sprays the treated water into the treatment tank.

[0011] According to the above configuration, the treated water in the treatment tank circulates while passing through the ejector. The ejector supplies microbubbles to the treated water. Microbubbles have a large surface area, which allows oxygen to dissolve easily in water, increasing the oxygen concentration in the water. Water supplied with microbubbles contains an increased amount of dissolved oxygen. Therefore, by spraying treated water containing a high amount of dissolved oxygen into the treatment tank using a nozzle, oxygen can be efficiently supplied to the entire treatment tank, which serves as the treatment space. This activates aerobic microorganisms throughout the treatment tank, further improving the efficiency of organic wastewater treatment.

[0012] The treatment tank is provided with a water level sensor that detects the level of the treated water stored in the lower part of the treatment tank, and a control unit that controls the operation of the purified water pump, and the control unit operates the purified water pump when the water level detected by the water level sensor reaches or exceeds a predetermined value, and stops the purified water pump when the water level falls below the predetermined value.

[0013] With this configuration, when the water level reaches a predetermined level, i.e., when a certain amount of treated water has accumulated in the lower part of the treatment tank, the purified water pump is operated to send some of the treated water to the outside, thereby effectively preventing the treatment tank from becoming full and causing the treated water to overflow from the treatment tank.

[0014] On the other hand, if the water level falls below a predetermined value, i.e., if the amount of treated water in the treatment tank becomes extremely low, the purified water pump is stopped to store the treated water, which prevents the carrier from drying out and prevents the aerobic microorganisms carried on the carrier from dying out.

[0015] The treatment tank may be provided with a lid that serves as the top surface, and the nozzles may spray the treated water toward the underside of the lid. This allows the treated water to be sprayed more efficiently over a wider area than when the nozzles are simply used to spray the treated water. The underside of the lid may also be provided with a number of protrusions that protrude downward. This allows for increased diffusion efficiency during spraying.

[0016] It is preferable to provide a solar panel that generates electricity to power the water purification pump. With this configuration, the water purification pump can be driven even in places where there is no commercial power supply. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide an organic wastewater treatment system that can efficiently supply oxygen to the entire treatment tank, which serves as the treatment space, and that can further improve the treatment efficiency of organic wastewater. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram illustrating a wastewater treatment facility including an organic wastewater treatment system according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram of an organic wastewater treatment system according to an embodiment of the present invention. [Figure 3] FIG. 3 illustrates the carrier of FIG. 2. [Figure 4] FIG. [Figure 5] FIG. 10 is a schematic diagram of an organic wastewater treatment system according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0020] Fig. 1 is a diagram illustrating a wastewater treatment facility 200 equipped with an organic wastewater treatment system according to this embodiment (hereinafter referred to as a treatment system 100). The wastewater treatment facility 200 illustrated in Fig. 1 includes a settling tank 210, a treatment tank 110 of the treatment system 100 of this embodiment, a sand filtration tank 220, and a storage tank 230.

[0021] In wastewater treatment equipment 200, water (organic wastewater) from a river or the like is sent to a settling tank 210 by a pump 202. In the settling tank 210, a process for removing sediment from solids such as sand is carried out. The treated water from which the sediment has been removed is sent to the treatment tank 110 of this embodiment by a pump 212. In the treatment tank 110, a biological process using aerobic microorganisms to decompose the organic matter in the treated water and ammonia to oxidize the organic matter are carried out, as will be described later.

[0022] The treated water that has been treated for decomposition of organic matter and the like is sent to the sand filtration tank 220 by the purified water pump 140 of the treatment system 100. In the sand filtration tank 220, treatment is performed to remove fine solids. The treated water that has been treated for solids removal 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 microbial activated carbon and disinfection. The treated water that has been treated for finishing is supplied to an external water-using facility by the pump 232.

[0023] Fig. 2 is a schematic diagram of an organic wastewater treatment system (treatment system 100) according to this embodiment. As illustrated in Fig. 2, the treatment system 100 of this embodiment includes a treatment tank 110 that stores a fluid, which is organic wastewater. A pump 212 of a settling tank 210 is connected to the treatment tank 110 via a supply pipe 102, and the fluid after sediment removal treatment in the settling tank 210 is supplied via the supply pipe 102. The supply pipe 102 is connected to a nozzle 104 arranged on the top of the treatment tank 110, and the fluid supplied to the treatment tank 110 is sprayed into the treatment tank 110 by the nozzle 104.

[0024] Carriers 130 carrying aerobic microorganisms are housed inside treatment tank 110 shown in Figure 2. As described above, the fluid sprayed from nozzles 104 comes into contact with carriers 130 as it flows down inside treatment tank 110. This causes a contact reaction with the aerobic microorganisms (not shown) carried by carriers 130, and organic matter contained in the fluid is decomposed.

[0025] Fig. 3 is a diagram illustrating the carrier 130 of Fig. 2. As shown in Fig. 3, the carrier 130 is configured to include a porous body 132 that supports aerobic microorganisms and absorbs water, and a frame body 134 that maintains the shape of the porous body 132. A polymer material having countless minute pores, such as a sponge, can be suitably used as the porous body 132. A highly rigid synthetic resin material can be suitably used as the frame body 134.

[0026] The material of the carrier 130 may be made of biodegradable fiber. As a specific example, coconut shell can be suitably used. This allows the carrier 130 itself to slowly biodegrade, thereby reducing the amount of industrial waste and easing the burden on the environment. As an example, the decomposition rate of the carrier 130 is such that, while organic substances contained in the treated water are decomposed over a cycle of several days, the carrier 130 is decomposed in about a year. When the weight of the carrier 130 decreases due to biodegradation in the treatment tank 110, additional carrier 130 can be replenished.

[0027] When using a fibrous material such as coconut shell, it is preferable to use a brush with the bristles facing the surface. For example, the carrier 130 may be formed by punching a block of biodegradable fiber into a cylindrical shape. Alternatively, the carrier 130 may be formed by punching a mat of biodegradable fiber into a disk shape and connecting multiple disks with biodegradable fasteners.

[0028] The fluid that has passed through the carrier 130 is stored in the lower part of the treatment tank 110 as treated water, and is pumped up at a predetermined timing by a purified water pump 140 through a purified water path 142. A predetermined amount of the pumped treated water is sent to an external facility (not shown) through a delivery path 144, and the rest is circulated to the treatment tank 110 through a circulation path 146.

[0029] A feature of the treatment system 100 of this embodiment is that an ejector 150 that generates fine bubbles is disposed in the path of the purified water pump 140, i.e., the purified water path 142. As the treated water passes through the ejector 150, outside air is taken in through an inlet 152, generating fine bubbles (microbubbles) in the treated water. The treated water that has passed through the ejector 150 is then sprayed into the treatment tank 110 by a nozzle 120 that is connected to the downstream side of the ejector 150.

[0030] Microbubbles have a large surface area, which makes it easier for oxygen to dissolve in water, increasing the oxygen concentration in the water, and the amount of dissolved oxygen increases in water to which microbubbles are supplied. Therefore, by spraying 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 130 can be activated throughout the entire treatment tank 110, making it possible to further improve the treatment efficiency of organic wastewater.

[0031] Furthermore, by using the ejector 150 as in the treatment system 100 of this embodiment, air and therefore oxygen can be supplied to the treated water without forced ventilation, i.e., 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 would occur when forced ventilation is performed.

[0032] A further feature of the treatment system 100 of this embodiment is that the connecting path 148 connecting the treatment tank 110 and the purified water pump 140 is provided with a water level sensor 160 that detects the water level of the treated water stored at the bottom of the treatment tank 110, and a control unit 190 that controls the operation of the purified water pump 140.

[0033] The control unit 190 operates 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. With this configuration, when a certain amount of treated water accumulates in the lower part of the treatment tank 110, a portion of the treated water pumped up by the purified water pump 140 is discharged to the outside. This makes it possible to effectively prevent the treated water from overflowing from the treatment tank 110 due to the treatment tank 110 becoming full.

[0034] Furthermore, if the carrier 130 becomes clogged with slime or the like, the fluid (treated water) sprayed from the nozzles 104, 120 will flow downward to the bottom of the treatment tank 110 without being captured by the carrier 130. This reduces the efficiency of the contact reaction between the fluid and the carrier 130, and the rate at which the water level rises increases. In such a case, the water level sensor 160 operates the purified water pump 140 according to the water level, thereby increasing the number of times the purified water pump 140 is started, increasing the amount of oxygen supplied to the carrier 130, and making it possible to increase the efficiency of the contact reaction between the fluid and the carrier 130.

[0035] On the other hand, the water level sensor 160 stops the purified water 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 delivery of the treated water to external equipment (not shown) is stopped, and the treated water is stored in the treatment tank 110. This makes it possible to prevent the carriers 130 from drying out and to prevent the aerobic microorganisms supported on the carriers 130 from dying out.

[0036] Furthermore, the treatment system 100 of this embodiment is equipped with a lid 170 that serves as the top surface of the treatment tank 110, and the nozzles 104, 120 spray 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 than when the nozzles 104, 120 simply spray the treated water (downward). This therefore promotes the activation of aerobic microorganisms, making it possible to further improve the treatment efficiency of organic wastewater.

[0037] FIG. 4 is a perspective view of the lid 170, as viewed from below. As shown in FIG. 4, a plurality of protrusions 172 protruding downward are formed on the back surface 170a of the lid 170. This makes it possible to improve the diffusion efficiency during water spraying, and thereby the above-mentioned effects. The plurality of protrusions 172 are also radially arranged at equal intervals on the back surface 170a of the lid 170. This arrangement makes it possible to obtain a higher diffusion effect than when the protrusions are arranged densely in certain areas or when they are arranged sparsely overall.

[0038] Furthermore, the treatment system 100 of this embodiment is equipped with a solar panel 180 that generates electricity to power the purified water pump 140, and the electricity generated by the solar panel 180 is supplied to the solar panel 180 through a power line 182. This makes it possible to drive the purified water pump 140 even in places where commercial power is not available. Therefore, the treatment system can be temporarily installed in disaster areas where a power outage has occurred, or in mountainous areas where electricity is not available.

[0039] Fig. 5 is a schematic diagram of an organic wastewater treatment system according to another embodiment. Portions that overlap with those of the treatment system 100 shown in Fig. 2 are designated by the same reference numerals, and the description thereof will be omitted.

[0040] 5, the purified water pump 140 is disposed below and in the center of the treatment tank 110. Like the purified water pump 140, the purified water path 142, the ejector 150, and the nozzle 120 are also located in the center of the treatment tank 110.

[0041] Furthermore, in the treatment system 100A, the underside of the lid 270 is formed in a dome shape. The dome shape is a hemispherical surface concave upward. The treated water that has passed through the ejector 150 is sprayed from the nozzle 120 onto the center of the dome. Similarly, the treated water supplied from the pump 212 through the supply pipe 102 is also sprayed from the nozzle 104 onto the center of the dome. The treated water sprayed from the nozzles 104 and 120 spreads along the wall surface of the dome of the lid 270 and is sprayed over a wide area onto the upper surface of the carrier 130.

[0042] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Industrial Applicability]

[0043] The present invention can be used as a wastewater treatment system for treating organic wastewater. [Explanation of symbols]

[0044] 100... treatment system, 102... supply pipe, 110... treatment tank, 104, 120... nozzle, 130... carrier, 132... porous body, 134... frame, 140... purified water pump, 142... purified water path, 144... delivery path, 146... circulation path, 148... connection path, 150... ejector, 152... suction port, 160... water level sensor, 170... lid, 180... solar panel, 182... power line, 190... control unit, 200... wastewater treatment equipment, 202... pump, 210... sedimentation tank, 212... pump, 220... sand filtration tank, 230... storage tank, 232... pump

Claims

[Claim 1] a cylindrical treatment tank for storing fluid that is organic wastewater; a carrier housed in the treatment tank and carrying aerobic microorganisms; a purified water pump that pumps up the treated water stored in the lower part of the treatment tank and circulates it back into the treatment tank and sends it out; an ejector that is disposed in a path of the purified water pump and generates fine bubbles; a nozzle communicating with the downstream side of the ejector and spraying the treated water into the treatment tank; A lid that serves as the top surface of the processing tank; Equipped with the underside of the lid is dome-shaped, and the diameter of the dome-shaped portion of the lid is smaller than the diameter of the processing tank; An organic wastewater treatment system characterized in that the fine bubbles are supplied to the treated water by the ejector, and the treated water containing the fine bubbles is sprayed from the nozzle toward the underside of the lid, thereby spraying the carrier in the treatment tank.

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