JP2014205098A - Wastewater purification apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve space saving of the whole apparatus in a state of maintaining the decomposition efficiency of an organic matter.SOLUTION: A wastewater purification apparatus 100 includes: a reaction tank 120 which stores microorganisms, brings the microorganisms into contact with wastewater DW to generate purified water PW, has a supply port 122 through which the wastewater DW is supplied and a discharge port 124 provided vertically below the supply port 122 to discharge the purified water PW, and forms a downward flow between the supply port 122 and the discharge port 124; a bubble introduction part 160 which introduces air bubbles into the purified water PW discharged from the discharge port 124 to generate a bubble liquid BW, which is bubble-containing purified water PW; and a bubble liquid return part 170 which returns the bubble liquid BW into a part located vertically below the supply port 122 and vertically above the discharge port 124 in the reaction tank 120. In the reaction tank 120, air bubbles in the bubble liquid BW adhere to suspended materials in the wastewater DW to separate the suspended materials by floatation.

Description

  The present invention relates to a wastewater purification apparatus that decomposes organic matter in wastewater using microorganisms.

  2. Description of the Related Art Conventionally, an activated sludge apparatus that includes a reaction tank and a sedimentation basin and purifies wastewater such as sewage and wastewater with activated sludge (aerobic organisms) is known. In such an activated sludge apparatus, the reaction tank holds activated sludge, and when wastewater is supplied to the reaction tank, organic matter in the wastewater is decomposed by the activated sludge, and the wastewater is purified to become purified water. . The purified water generated in the reaction tank is supplied to the sedimentation basin together with the activated sludge, and the activated sludge is settled and separated in the sedimentation basin, and the purified water is discharged. On the other hand, the activated sludge separated and separated in the settling basin is returned to the reaction tank and reused. In such an activated sludge apparatus, the installation area of a sedimentation basin was large and there existed a subject that an installation place was restrict | limited.

  Therefore, air is blown into the suspension of purified water and activated sludge sent from the reaction tank under pressure to dissolve it in a supersaturated state, and then the atmospheric pressure is restored (restored). A technique (pressurized flotation separation method) that generates air bubbles inside and floats and separates activated sludge has been developed (for example, Non-Patent Document 1).

  However, when air is blown into the suspension under a pressurized condition, it is necessary to pressurize the air to a high pressure of about 0.3 MPa to 0.4 MPa, and the cost for pressurizing the air is required. In addition, even the separation technology of the pressurized flotation separation method requires an air dissolution tank for dissolving air to supersaturation and a flotation tank for levitating and separating activated sludge. Although it can be reduced, there is still a problem that the installation location is limited.

  Therefore, a part of the liquid (purified water) is extracted from the levitation tank and compressed air is introduced, and the liquid into which the compressed air is introduced is mixed with the suspension sent from the reaction tank, and the levitation tank is obtained as a mixed liquid. A technique is disclosed in which activated sludge is levitated and separated only by a flotation tank without supplying an air dissolution tank (for example, Patent Document 1). In the technique of Patent Document 1, a mixed solution supply port is provided in the lower part of the levitation tank in order to take a wide area for levitation separation.

Japanese Patent No. 2892604

Edited by the Japan Chemical Industry Association, “Water Pollution Prevention Technology and Equipment 2. Physical and Chemical Water Treatment Technology and Equipment (above)”, Baifukan Co., Ltd., published on November 30, 1980, Figure 4-15

  However, even the activated sludge apparatus using the technology of Patent Document 1 requires a floating tank, so it is difficult to say that significant space saving is achieved and the problem that the installation location is limited is solved. Can not.

  Then, this inventor applied the technique of patent document 1 to the reaction tank, and discovered the structure which performs purification | cleaning of waste water, and isolation | separation of activated sludge in parallel in a reaction tank. Specifically, activated sludge is stored in a reaction tank, a part of the liquid (purified water) is extracted from the lower part of the reaction tank, compressed air is introduced, and the purified water into which the compressed air has been introduced is discharged into the waste water. Mix and feed to reaction vessel.

  However, in the technique of Patent Document 1, since wastewater and bubbles are simultaneously supplied to the reaction tank, the contact area for contact between the wastewater and activated sludge is small (the contact time is short), and the organic matter in the wastewater is decomposed. There is a problem of low efficiency.

  Then, this invention aims at provision of the waste water purification apparatus which can aim at the space saving of the whole apparatus in the state which maintained the decomposition efficiency of organic substance.

  In order to solve the above problems, a wastewater purification apparatus according to the present invention is a wastewater purification apparatus that decomposes organic matter in wastewater to generate purified water, contains microorganisms, and contacts the microorganisms and wastewater. A tank that generates purified water, and has a supply port to which drainage is supplied and a discharge port that is provided vertically below the supply port to discharge purified water, and flows downward between the supply port and the discharge port. A bubble is introduced into the purified water discharged from the discharge port, the bubble introduction unit for generating bubble liquid as purified water containing bubbles, and the bubble liquid is supplied to the supply port in the reaction tank. A bubble liquid return section that is vertically below and returns to the top vertically of the discharge port, and in the reaction tank, bubbles in the bubble liquid adhere to the suspended matter in the drainage, and the suspension is floated and separated. It is characterized by making it.

  The microorganism may be an anaerobic organism, and the bubble introduction unit may introduce biogas generated by the anaerobic organism by decomposing organic matter in the wastewater into the purified water as bubbles.

  Further, the average particle diameter of the bubbles introduced by the bubble introduction part may be a particle diameter at which the suspension floating speed due to the adhesion of the bubbles is larger than the flow velocity of the downward flow in the reaction tank.

  Further, the bubble introduction part is formed of a porous body having a plurality of holes, and a porous pipe through which the purified water flows, and a gas introduction part that introduces gas into the purified water from the outside of the porous pipe through the plurality of holes, , May be provided.

  In addition, the bubble introduction unit may include an aspirator.

  Moreover, it is good also as comprising one or several support | carriers comprised with porous resin and carrying | supporting microorganisms in the reaction tank.

  According to the present invention, it is possible to save the space of the entire apparatus while maintaining the decomposition efficiency of organic matter.

It is a figure for demonstrating a waste water purification apparatus. It is a figure for demonstrating the waste water purification apparatus of the modification 1. FIG. It is a figure for demonstrating the waste water purification apparatus of the modification 2. FIG. It is a figure for demonstrating the waste water purification apparatus of the modification 3. FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Drainage purification device 100)
FIG. 1 is a view for explaining a waste water purification apparatus 100. In FIG. 1 of the present embodiment, an X axis (horizontal direction), a Y axis (horizontal direction), and a Z axis (vertical direction) that intersect perpendicularly are defined as illustrated. The waste water purification apparatus 100 according to this embodiment uses an anaerobic organism as a microorganism, decomposes organic matter in the waste water DW, and generates purified water PW.

  As shown in FIG. 1, the drainage purification apparatus 100 includes a drainage supply unit 110, a reaction tank 120, a carrier 130, a water seal 140, a purified water storage tank 150, a bubble introduction unit 160, and a bubble liquid return unit. 170 and an extraction mechanism 180.

  The waste water supply unit 110 includes a pipe 112 connected to the supply port 122 of the reaction tank 120 and a pump 114, and supplies waste water DW containing organic matter to the reaction tank 120.

  The reaction tank 120 contains microorganisms, and generates the purified water PW by bringing the waste water DW supplied by the waste water supply unit 110 into contact with the microorganisms. In addition, as described above, since the microorganisms housed in the reaction tank 120 in this embodiment are anaerobic organisms, the reaction tank 120 is a closed space in order to suppress contact between the microorganisms and air (oxygen). ing.

  The reaction tank 120 is provided with a supply port 122 to which the drainage DW is supplied, and a discharge port 124 that is provided vertically below the supply port 122 (in the Z-axis direction in FIG. 1) and discharges the purified water PW. The downward flow of the drainage DW or the purified water PW (liquid flow directed vertically downward) is formed between the supply port 122 and the discharge port 124.

  In the present embodiment, the reaction tank 120 contains microorganisms carried on one or more carriers 130. The carrier 130 is a sponge made of a porous resin (for example, polyurethane foam) and carries microorganisms. With the configuration in which the reaction tank 120 contains the microorganisms supported on the carrier 130, it is possible to suppress the situation where the microorganisms get on the downward flow and are discharged from the discharge port 124, and the microorganisms are maintained in the reaction tank 120. It becomes possible to leave.

  Further, a partition plate 126 is provided between the supply port 122 and the discharge port 124 in the reaction tank 120 to partition the inner region of the reaction tank 120 vertically (in the Z-axis direction in FIG. 1). The partition plate 126 is provided with a plurality of holes 126a smaller than the diameter of the carrier 130. By accommodating the carrier 130 above the partition plate 126, the carrier below the partition plate 126, that is, the carrier to the discharge port 124 is provided. The outflow of 130 can be prevented.

  Further, in the reaction tank 120, the bubble liquid return described later is vertically below the supply port 122 and vertically above the discharge port 124, and in this embodiment, vertically below the supply port 122 and vertically above the partition plate 126. A supply port 128 to which the bubble liquid BW (purified water PW containing bubbles) returned from the unit 170 is supplied is provided. The effect of supplying the bubble liquid BW to the reaction tank 120 will be described in detail later.

  In this manner, when the waste water DW and the microorganisms come into contact with each other in the reaction tank 120, the organic matter contained in the waste water DW is decomposed by the microorganisms to become biogas BG (methane, carbon dioxide, etc.) and removed from the waste water DW. Thus, purified water PW is generated. The biogas BG generated in the reaction tank 120 is sent to the water seal 140 through the pipe 142, and then used as fuel for a boiler or the like, or sent to the bubble inlet 160 described later through the pipe 162. On the other hand, the purified water PW generated in the reaction tank 120 is discharged to the purified water storage tank 150 through the discharge port 124 and the pipe 152.

  The purified water storage tank 150 is a tank for storing the purified water PW, and a supply port 154 connected to the pipe 152 is provided in the lower part. Further, a discharge port 156 is provided vertically above the supply port 154 in the purified water storage tank 150, and the purified water PW stored in the purified water storage tank 150 is discharged to the outside through the discharge port 156. It becomes. In addition, a delivery port 158 connected to the porous tube 166 of the bubble introduction unit 160 via the pipe 164 is provided vertically above the supply port 154 and below the discharge port 156. Water PW is also sent to the porous tube 166.

  The bubble introduction unit 160 introduces the biogas BG into the purified water PW sent from the purified water storage tank 150 to generate the bubble liquid BW. In the present embodiment, the bubble introduction unit 160 includes a porous tube 166 and a gas introduction unit 168. The porous tube 166 is formed of a porous body having a plurality of holes. One end of the porous tube 166 is connected to the pipe 164, and the other end is connected to the pipe 172 constituting the bubble liquid return unit 170. Yes.

  The gas introduction unit 168 includes an outer tube that surrounds the porous tube 166, and introduces the biogas BG generated in the reaction tank 120 into the purified water PW as bubbles. More specifically, the gas introduction part 168 is connected to the pipe 162. When the purified water PW flows through the porous pipe 166 by driving the pump 174 of the bubble liquid return part 170 described later, the gas introduction part 168 is caused by the venturi effect. Compared with the outside of the porous tube 166 (the space 166a formed between the porous tube 166 and the gas introduction part 168), the inside of the porous tube 166 has a negative pressure. If it does so, biogas BG in the gas introduction part 168 will be introduce | transduced as a bubble to the purified water PW which distribute | circulates the inside of the porous pipe | tube 166 through a some hole. Thus, the bubble introduction unit 160 generates the bubble liquid BW in which the bubbles of the biogas BG are introduced into the purified water PW.

  The bubble liquid return unit 170 includes a pipe 172 and a pump 174, and returns the bubble liquid BW to the supply port 128 of the reaction tank 120. More specifically, the pipe 172 has one end connected to the porous pipe 166 and the other end connected to the supply port 128. Therefore, when the pump 174 is driven, the bubble liquid BW generated in the porous tube 166 is returned to the supply port 128.

  In the present embodiment, although the microorganisms are supported on the carrier 130, there are some microorganisms that float or detach from the carrier 130 and float as a suspension in the waste water DW. In particular, anaerobic organisms (for example, hydrolyzing bacteria) other than methanogens are likely to float in the wastewater DW because of their low cohesiveness. Therefore, if no measures are taken, floating microorganisms are discharged from the discharge port 124 along with the downward flow, and the concentration of microorganisms in the reaction tank 120 is lowered.

  Therefore, the structure in which the bubble liquid BW is returned to the reaction tank 120 allows the bubbles in the bubble liquid BW to adhere to the suspension in the drainage DW in the reaction tank 120, and the suspension is floated and separated. Is possible. That is, microorganisms floating as a suspension can be floated and separated in the reaction tank 120. Therefore, it is possible to avoid a situation where microorganisms flow out from the discharge port 124, and it is possible to keep the microorganisms in the reaction tank 120. Thereby, the tank for exclusive use for isolate | separating microorganisms becomes unnecessary, and the space-saving of the installation area (installation volume) of the waste water purification apparatus 100 whole can be achieved.

  In addition, the bubble liquid return unit 170 according to the present embodiment returns the bubble liquid BW vertically below the supply port 122 (supply port 128), so that the gap between the supply port 122 and the supply port 128 is used for floating separation. A region is formed, and microorganisms are dispersed in the region. Accordingly, the drainage DW supplied from the supply port 122 can come into contact with microorganisms in a wide area between the supply port 122 and the supply port 128, and the organic matter in the drainage DW can be sufficiently decomposed. .

  Furthermore, since bubbles rise between the supply port 122 and the supply port 128, the liquid in the reaction tank 120 is agitated by the bubbles, and the drainage DW does not flow evenly, and the desired residence time is reduced. It is a flow that flows out in a short time without passing), and the situation where the decomposition of the organic matter becomes insufficient can be suppressed.

  Further, since the bubble liquid return unit 170 returns the bubble liquid BW vertically above the discharge port 124, it is possible to avoid a situation where bubbles are discharged from the discharge port 124.

  The bubbles introduced into the reaction tank 120 are more likely to adhere to the suspension when the particle size is smaller. However, if the bubbles are too small, the flying speed is too low and the air bubbles are discharged in a descending flow. On the other hand, if the bubbles are too large, the ascending speed is high so that they are not discharged along with the descending flow, but the adhesion efficiency to the suspension is low and microorganisms are discharged.

  Therefore, the bubble introduction unit 160 sets the average particle diameter of the bubbles to be introduced into the purified water PW so that the suspension rising speed due to the bubbles adhering to the reaction tank 120 is larger than the flow rate of the downward flow in the reaction tank 120. It is set as the particle size which becomes (for example, about 30 micrometers-about 300 micrometers). Thereby, microorganisms can be floated and separated, and microorganisms discharged from the discharge port 124 can be reduced.

  Moreover, the bubble introduction part 160 comprised by the porous pipe | tube 166 mentioned above and the gas introduction part 168 is easy to control the particle size of the bubble introduced. More specifically, since the particle diameter to be introduced is determined by the pore diameter of the porous tube 166, for example, if the pore diameter of the porous tube 166 is about 0.5 μm to 5 μm, the particle diameter of the bubbles is 30 μm to It can be about 300 μm.

  The extraction mechanism 180 includes a pipe 182 that connects the reaction tank 120 and a sludge storage tank (not shown), and a valve 184 provided in the pipe 182. The connection port of the pipe 182 in the reaction tank 120 is provided vertically above the supply port 128 and vertically below the supply port 122.

  The extraction mechanism 180 is driven when the concentration of microorganisms in the reaction tank 120 exceeds a predetermined value. Here, the predetermined value is an upper limit value of the concentration of microorganisms in which the organic matter is properly decomposed in the reaction tank 120. When the extraction mechanism 180 is driven, the valve 184 is first opened. Then, the liquid containing the microorganisms (suspension) in the reaction tank 120 is supplied to the sludge storage tank through the pipe 182. Then, when the drive of the extraction mechanism 180 is stopped, the valve 184 is closed. In addition, although the deposit produced in the sludge storage tank is sent to the sludge treatment process including a dehydration process, you may mix the supernatant liquid produced in the sludge storage tank with the waste_water | drain DW.

  With the configuration including the extraction mechanism 180, the concentration of microorganisms in the reaction tank 120 can be properly maintained, and the decomposition efficiency of organic matter in the reaction tank 120 can be maintained.

  As described above, according to the waste water purification apparatus 100 according to the present embodiment, two processes such as decomposition of organic matter and separation of microorganisms can be performed with a simple configuration in which bubbles are introduced into the reaction tank 120 that forms a downward flow. The reaction can be performed only in the reaction tank 120. Thereby, the waste water purification apparatus 100 can achieve space saving of the entire apparatus while maintaining the decomposition efficiency of the organic matter.

  Further, since the bubble introduction unit 160 can supply the bubbles to the reaction tank 120 without applying pressure, it is possible to reduce the power for generating bubbles as compared with the pressurized flotation separation method. .

(Modification 1: Wastewater purification device 200)
In the waste water purification apparatus 100 described above, the bubble introduction unit 160 configured by the porous tube 166 and the gas introduction unit 168 has been described. However, as long as the bubbles can be introduced into the purified water PW, the configuration of the bubble introduction unit is not limited.

  FIG. 2 is a view for explaining the waste water purification apparatus 200 of the first modification. In FIG. 2, the X axis (horizontal direction), the Y axis (horizontal direction), and the Z axis (vertical direction) that intersect perpendicularly are defined as shown. The waste water purification apparatus 200 according to this embodiment uses an anaerobic organism as a microorganism, decomposes organic matter in the waste water DW, and generates purified water PW.

  As shown in FIG. 2, the drainage purification apparatus 200 includes a drainage supply unit 110, a reaction tank 120, a carrier 130, a water seal 140, a purified water storage tank 150, a bubble introduction unit 260, and a bubble liquid return unit. 170 and an extraction mechanism 180. In addition, about the component substantially equivalent to the component of the waste water purification apparatus 100 mentioned above, the same code | symbol is attached | subjected and duplication description is abbreviate | omitted, and here the bubble introduction part 260 from which a structure differs is explained in full detail. In the first modification, the bubble introduction unit 260 is configured by an aspirator. By configuring the bubble introduction unit 260 with an aspirator, the cost required for the bubble introduction unit 260 can be reduced.

(Modification 2: Wastewater purification device 300)
In the waste water purification apparatuses 100 and 200 described above, the configuration in which the pump 174 is disposed on the downstream side of the bubble introduction units 160 and 260 has been described. However, the arrangement of the pump 174 is not limited. FIG. 3 is a view for explaining a waste water purification apparatus 300 of a second modification. In FIG. 3, an X axis (horizontal direction), a Y axis (horizontal direction), and a Z axis (vertical direction) that intersect perpendicularly are defined as illustrated. The waste water purification apparatus 300 according to this embodiment uses an anaerobic organism as a microorganism, decomposes organic matter in the waste water DW, and generates purified water PW.

  As shown in FIG. 3, the waste water purification apparatus 300 includes a waste water supply unit 110, a reaction tank 120, a carrier 130, a water seal 140, a purified water storage tank 150, a bubble introduction unit 160, and a bubble liquid return unit. 370, the pump 380, and the extraction mechanism 180 are comprised. In addition, about the component substantially equivalent to the component of the waste water purification apparatus 100 mentioned above, the same code | symbol is attached | subjected and duplication description is abbreviate | omitted, Here, the bubble liquid return part 370 and the pump 380 which are different in a structure. Will be described in detail.

  In the second modification, the bubble liquid return unit 370 includes a pipe 172 and a pump 374, and returns the bubble liquid BW to the supply port 128 of the reaction tank 120. More specifically, in the second modification, the pump 374 is provided in a pipe 164 disposed on the upstream side of the bubble introduction unit 160. Thereby, introduction of the biogas BG to the pump 374 can be prevented, and problems of the pump 374 due to the biogas BG can be avoided.

  In addition, when the pump 374 is disposed on the upstream side of the bubble introduction unit 160, the pressure of the purified water PW flowing through the porous pipe 166 is higher than that in the waste water purification apparatus 100. A pump 380 for boosting the gas BG may be provided. Thereby, the bubble of the biogas BG can be efficiently introduced into the purified water PW.

(Modification 3: Wastewater purification device 400)
Although the waste water purification apparatuses 100, 200, and 300 described above use anaerobic organisms as microorganisms, aerobic organisms may be used. FIG. 4 is a view for explaining a waste water purification apparatus 400 of Modification 3. In FIG. 4, an X axis (horizontal direction), a Y axis (horizontal direction), and a Z axis (vertical direction) that intersect perpendicularly are defined as illustrated. The waste water purification apparatus 400 according to the present embodiment uses aerobic organisms as microorganisms, decomposes organic matter in the waste water DW, and generates purified water PW.

  As shown in FIG. 4, the waste water purification apparatus 400 includes a waste water supply unit 110, a reaction tank 420, a carrier 130, a purified water storage tank 150, a bubble introduction unit 460, a bubble liquid return unit 170, and an extraction mechanism. 180. In addition, about the component substantially equivalent to the component of the waste water purification apparatus 100 mentioned above, the same code | symbol is attached | subjected and duplication description is abbreviate | omitted, Here, the reaction tank 420 and the bubble introduction part 460 which are different in a structure are demonstrated. Will be described in detail.

  The reaction tank 420 is a tank whose upper surface is opened, and maintenance of the reaction tank 420 is easy.

  The bubble introduction part 460 includes a porous tube 166 and a gas introduction part 468, and introduces air into the purified water PW as bubbles. Thereby, air can be supplied to the reaction tank 420 and oxygen can be dissolved in the waste water DW as well as the floating separation of microorganisms. Therefore, the oxygen concentration in the wastewater DW can be improved, microorganisms can be grown, and the decomposition rate of organic substances contained in the wastewater DW can be improved.

(Example)
As an example, when the waste water DW containing organic matter was treated using the waste water purification apparatus 400, the transparency of the purified water PW discharged from the discharge port 156 was measured. Further, as a comparative example, air is blown directly into the lower part of the reaction tank without introducing bubble liquid, and a region not stirred is provided in the reaction tank, and microorganisms are precipitated and separated in this region, and purified water PW is supplied to the reaction tank. When the wastewater DW containing organic matter was treated using a wastewater purification device that overflowed from the upper end of the water, the transparency of the overflowed purified water PW was measured. In addition, a downward flow is formed in the reaction tank 420 of the example, and a circulation flow for stirring the inside of the reaction tank is formed in the reaction tank of the comparative example. Further, the residence time of the waste water DW in the example (a value obtained by dividing the volume of the reaction tank 420 by the flow rate of the waste water DW) was 3 days, and the residence time of the waste water DW in the comparative example was 4 days. Furthermore, the filling rate of the carrier 130 in the reaction tank 420 was about 30% in both the example and the comparative example. The results are shown in Table 1 below.

  As shown in Table 1, in the example, the transparency of the purified water PW was 50 cm or more, whereas in the comparative example, the transparency of the purified water PW was as low as 20 to 40 cm. Thereby, even if the residence time was short, it was confirmed that the efflux amount of the microorganism was smaller in the example than in the comparative example. Therefore, it was found that the effluent separation of microorganisms (suspension) is efficiently performed in the waste water purification apparatus 400.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the said embodiment, although the waste water purification apparatus 100,200,300,400 demonstrated the structure provided with the purified water storage tank 150, the purified water storage tank 150 is not an essential structure. Instead of the purified water storage tank 150, for example, an extension pipe having one end connected to the outlet 124 of the reaction tanks 120 and 420, extending vertically upward outside the reaction tanks 120 and 420, and having the other end opened. It is also possible to connect a discharge pipe folded vertically downward to the extension pipe. Then, when the drainage DW is continuously supplied to the reaction tanks 120 and 420 by the drainage supply unit 110, the water level of the drainage DW in the reaction tanks 120 and 420 is the lower end of the discharge pipe at the connection position between the extension pipe and the discharge pipe. The purified water PW is discharged through the extension pipe and the discharge pipe in a state where the height is maintained at substantially the same height. In this case, the pipe 164 is preferably connected vertically below the discharge pipe in the extension pipe.

  In the above embodiment, the microorganisms are accommodated in the reaction tanks 120 and 420 while being supported on the carrier 130. However, the microorganisms may be accommodated in the reaction tanks 120 and 420 as they are. Even in this case, the wastewater purification apparatuses 100, 200, 300, and 400 according to the present embodiment have a simple configuration in which bubbles are introduced into the reaction tanks 120 and 420 that form the downward flow, and the decomposition of organic matter and microorganisms. Two treatments, such as separation, can be performed only in the reaction tanks 120 and 420.

  INDUSTRIAL APPLICATION This invention can be utilized for the waste water purification apparatus which decomposes | disassembles the organic substance in waste water using microorganisms.

100, 200, 300, 400 Wastewater purification device 120, 420 Reaction tank 130 Carrier 160, 260, 460 Bubble introduction part 166 Porous pipe 168, 468 Gas introduction part 170, 370 Bubble liquid return part

Claims (6)

A wastewater purification device that generates purified water by decomposing organic matter in wastewater by microorganisms,
A tank for containing the microorganisms and generating the purified water by bringing the microorganisms into contact with the waste water, a supply port to which the waste water is supplied, and a purified water provided vertically below the supply port. A reaction tank having a discharge port for discharging, and a downward flow is formed between the supply port and the discharge port;
A bubble introduction unit that introduces bubbles into the purified water discharged from the discharge port to generate a bubble liquid that is purified water containing the bubbles;
A bubble liquid return section for returning the bubble liquid to a position vertically below the supply port and vertically above the discharge port in the reaction tank;
With
In the reaction tank, the waste water purification apparatus is characterized in that bubbles in the foam liquid adhere to the suspension in the waste water to float and separate the suspension. The microorganism is an anaerobic organism,
2. The wastewater purification apparatus according to claim 1, wherein the bubble introduction unit introduces biogas generated by the anaerobic organism by decomposing organic matter in the wastewater into the purified water as bubbles.   The average particle diameter of the bubbles introduced by the bubble introduction part is a particle diameter at which the suspension floating speed due to the adhesion of the bubbles is larger than the flow velocity of the downward flow in the reaction tank. The waste water purification apparatus according to claim 1 or 2. The bubble introduction part is
A porous tube formed of a porous body having a plurality of pores, through which the purified water flows,
A gas introduction part for introducing gas into the purified water through the plurality of holes from the outside of the porous tube;
The waste water purification apparatus according to any one of claims 1 to 3, further comprising:   The drainage purification apparatus according to any one of claims 1 to 3, wherein the bubble introduction unit includes an aspirator.   The waste water purification apparatus according to any one of claims 1 to 5, further comprising one or a plurality of carriers made of a porous resin and supporting the microorganisms in the reaction tank.

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