Purification equipment

Abstract

To provide a purifier with a simple structure, yet with excellent processing efficiency and energy saving.SOLUTION: A purifier 1 has a cylindrical septic tank 2, a raw water supply pipe 4 connected to a pump 3 that supplies raw water to the septic tank 2 by pumping with the pump 3, and a discharge pipe 7 that discharges treated water purified by an action of aerobic microorganisms in the septic tank 2. An air inlet 4b is provided in the middle of the raw water supply pipe 4, and a static mixer 6 is installed between the air inlet 4b and the supply port of the raw water supply pipe 4. Raw water and air are mixed and supplied to the septic tank 2 with the static mixer 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a purification device, and more particularly to a purification device that utilizes an activated sludge process using aerobic microorganisms. [Background technology]

[0002] Wastewater containing high concentrations of pollutants such as nitrogen, phosphorus, and organic matter, which increase biochemical oxygen demand (BOD) and suspended solids (SS), is a cause of environmental pollution, such as river contamination and red tide outbreaks. Conventionally, the activated sludge process (biochemical treatment), which treats sludge with microorganisms, has been widely used as a method for treating wastewater containing such high concentrations of pollutants.

[0003] In general, the activated sludge process is a method of decomposing and removing pollutants by aerating the inside of a septic tank to promote the activity of aerobic microorganisms. In the activated sludge process, it is important to expose the aerobic microorganisms to as much air as possible. For example, in the biological treatment device of Patent Document 1, in order to more efficiently treat organic matter contained in raw water, air bubbles contained in dissolved oxygen water are atomized by a pump and sent to the septic tank, where they are efficiently contact-oxidized by the microorganisms. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-151475 Summary of the Invention [Problem to be solved by the invention]

[0005] In the biological treatment device of Patent Document 1, carriers are suspended in a septic tank, and activated sludge is allowed to adhere to and grow on the carriers, separating the supernatant water from the flocs. However, this device requires carriers to be suspended in the septic tank, a support bed, and mesh plates to prevent the carriers from flowing out, which tends to make the device structure complicated. In addition, a stirring pump is used to break down air bubbles and dissolve them in the water to be treated, but there is room for improvement in terms of energy conservation.

[0006] The present invention has been made in view of the above circumstances, and has an object to provide a purification device that has a simple structure yet is excellent in treatment efficiency and energy saving. [Means for solving the problem]

[0007] The purification device of the present invention comprises a cylindrical septic tank, a raw water supply pipe connected to a pump and supplying raw water to the septic tank by the pressure of the pump, and a discharge pipe for discharging treated water purified in the septic tank by the action of aerobic microorganisms, wherein an air inlet for introducing air is provided midway through the raw water supply pipe, and a static mixer is provided between the air inlet and the supply port of the raw water supply pipe, and the raw water and the air are mixed by the static mixer and supplied to the septic tank.

[0008] The septic tank has a cylindrical partition wall that divides the space within the tank, the inside and outside of the cylindrical partition wall are connected by an opening at the lower end of the cylindrical partition wall, and the raw water supply pipe is inserted into the cylindrical partition wall in a direction perpendicular to the height direction of the septic tank and is arranged along the inner wall surface of the cylindrical partition wall.

[0009] The purification device has a circulation pipe that circulates the water to be treated in the septic tank outside the tank, and the circulation pipe is connected to the raw water supply pipe, and has a circulation path through which the water to be treated introduced into the circulation pipe passes through the static mixer and is supplied again to the septic tank.A funnel is provided inside the cylindrical partition and above the raw water supply pipe for introducing the water to be treated in the septic tank into the circulation pipe, and the funnel is installed with its opening facing upward.

[0010] The inner diameter of the cylindrical partition wall is 50% to 80% of the inner diameter of the septic tank.

[0011] The cylindrical partition wall is characterized in that it has a truncated cone shape. [Effects of the Invention]

[0012] The purifier of the present invention comprises a septic tank, a raw water supply pipe, and a discharge pipe. An air inlet is provided in the raw water supply pipe for introducing air, and a static mixer is provided between the air inlet and the supply port of the raw water supply pipe. The static mixer mixes the raw water and air before supplying it to the septic tank. This allows for the generation of relatively fine bubbles without the need for a separate power source, and the production of highly oxygenated water, which promotes the activity of aerobic microorganisms in the septic tank. This results in a purifier with a simple structure, yet excellent treatment efficiency and energy conservation.

[0013] The septic tank has a cylindrical partition wall that divides the tank's interior space. The interior and exterior of the cylindrical partition wall are connected by an opening at the bottom of the cylindrical partition wall. The raw water supply pipe is inserted into the cylindrical partition wall perpendicular to the height of the septic tank and is positioned along the inner wall surface of the cylindrical partition wall. High-oxygen water discharged from the supply port flows along the curve of the inner wall surface, creating a swirling flow inside the cylindrical partition wall. This allows the water to be treated inside the tank to be agitated, promoting the activity of aerobic microorganisms and further improving treatment efficiency. Furthermore, since there is no need for an agitation device to agitate the septic tank, this system is also energy-efficient.

[0014] The septic tank has a circulation pipe that circulates the untreated water from the septic tank outside the tank, and the circulation pipe is connected to a raw water supply pipe, and the untreated water introduced into the circulation pipe passes through a static mixer and is then returned to the septic tank. This allows for improved treatment capacity without increasing the size of the septic tank. Furthermore, a funnel is provided inside the cylindrical partition above the raw water supply pipe for introducing the untreated water from the septic tank into the circulation pipe. The funnel is installed with its opening facing upward, allowing the untreated water rising due to the swirling flow to easily be introduced into the circulation pipe. This improves the circulation efficiency of the untreated water, and ultimately the treatment efficiency.

[0015] Since the cylindrical partition wall has a truncated cone shape, the settling speed of activated sludge outside the cylindrical partition wall can be increased, thereby improving the treatment efficiency. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram of one embodiment of a purification device of the present invention. [Figure 2] FIG. 2 is a vertical cross-sectional view of the septic tank of FIG. 1. [Figure 3] FIG. 1 is a plan view of the inside of a septic tank viewed from above. [Figure 4] FIG. 1 is a diagram showing the circulation of water to be treated and activated sludge in a septic tank. [Figure 5] FIG. 10 is a vertical cross-sectional view of a septic tank according to another embodiment of the septic apparatus of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] One embodiment of the purifier of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of the purifier. A wastewater treatment method using the purifier of the present invention is a method of decomposing and removing pollutants in wastewater by aerating the inside of a septic tank to promote the activity of aerobic microorganisms. The raw water supplied to the purifier 1 may be sludge water such as sewage, industrial wastewater, or industrial effluent, or may be primary treated water in which suspended solids have been precipitated and removed by anaerobic microorganisms.

[0018] As shown in Figure 1, the purifier 1 comprises a cylindrical septic tank 2, a pump 3, a raw water supply pipe 4 for supplying raw water to the septic tank 2, a discharge pipe 7 for discharging treated water purified by the action of aerobic microorganisms in the septic tank 2, a circulation pipe 10 for circulating the water to be treated in the septic tank 2 outside the tank, and a discharge pipe 11 for discharging activated sludge. In the present invention, the internal volume of the septic tank 2 is not limited, and can be adapted to small to large sizes. The internal volume is, for example, 1 m 3 ~30m 3 and preferably 1 m 3 ~15~m 3 is.

[0019] The raw water supply pipe 4 is connected to a pump 3, and raw water is supplied to the septic tank 2 from a supply port 4a by the pressure of the pump 3. As shown in FIG. 1, an air inlet 4b connected to an air pipe 5 is provided midway along the raw water supply pipe 4. By introducing air from the air inlet 4b, the raw water and air are mixed downstream of the air inlet 4b. Note that the raw water supply pipe 4 may be configured to supply air using a blower (not shown), or the raw water supply pipe 4 may be configured to draw air into the pipe.

[0020] The present invention is characterized by providing a static mixer 6 between the air inlet 4b and the supply port 4a in the raw water supply pipe 4. This static mixer 6 agitates and mixes the raw water and air, generating relatively fine bubbles and dissolving oxygen to produce highly oxygenated water. Supplying this highly oxygenated water containing fine bubbles to the septic tank 2 promotes the activity of aerobic microorganisms and improves treatment efficiency. The size of these fine bubbles is, for example, 10 μm to 100 μm, and preferably 10 μm to 50 μm. Note that if the bubbles are nano-sized (less than 1 μm), the bubbles themselves become stabilized and are less likely to dissolve.

[0021] In the purification apparatus of the present invention, energy consumption can be reduced when supplying the water to be treated by providing a static mixer 6, which is a static mixing means, instead of the conventional dynamic mixing means. In addition, by configuring the static mixer 6 to be detachable from the raw water supply pipe 4, cleaning and maintenance work are easier than with dynamic mixing means.

[0022] A static mixer has a structure that includes one or more elements, each of which is a rectangular plate twisted 180 degrees. Inside the static mixer, air bubbles in the raw water are broken down into finer pieces, and the contact interface becomes larger, thereby increasing the efficiency of air dissolution and producing highly oxygenated water. Well-known static mixers can be used as the static mixer.

[0023] Generally, the saturated dissolved oxygen content at 20°C and atmospheric pressure of 1 atm is 8.84 mg / L. In order to ensure that the dissolved oxygen content of the high-concentration oxygen water that passes through the static mixer and is released from the supply port 4a is within a suitable range, it is preferable to mix the raw water and air in an appropriate ratio. The flow rate of the raw water can be measured using flow meters F1 and F2, and the amount of air blown in can be measured using a flow meter (not shown) installed in the air pipe 5.

[0024] In Figure 1, septic tank 2 has a true cylindrical appearance consisting of base 2a, which serves as the bottom, cylindrical side surface 2b, and top surface 2c. A raw water supply pipe 4, a discharge pipe 7, a circulation pipe 10, and a discharge pipe 11 are connected to cylindrical side surface 2b. The connection positions of each pipe to cylindrical side surface 2b in the height direction of septic tank 2 are, from top to bottom, discharge pipe 7, circulation pipe 10, raw water supply pipe 4, and discharge pipe 11. The circulation pipe 10 and discharge pipe 11 are connected outside the septic tank and further connected to pump 3. Operation of pump 3 enables the circulation of treated water within the septic tank and the discharge of activated sludge.

[0025] Next, the internal structure of the septic tank will be described with reference to Figures 2 and 3. Figure 2 is a cross-sectional view of the septic tank in the height direction, and Figure 3 is a plan view of the inside of the septic tank seen from above. As shown in Figure 2, the septic tank 2 has a cylindrical partition wall 8 that divides the space inside the tank. The cylindrical partition wall 8 is suspended and fixed from the upper surface 2c of the septic tank 2. The upper end of the cylindrical partition wall 8 is closed, and the lower end is open via an opening 8a. The space inside the septic tank 2 is divided by the cylindrical partition wall 8 into an inside (cylindrical inner tank 2d) and an outside (cylindrical outer tank 2e), and the cylindrical inner tank 2d and the cylindrical outer tank 2e are connected via the opening 8a.

[0026] A raw water supply pipe 4 is disposed horizontally below the cylindrical inner tank 2d. The supply port 4a of the raw water supply pipe 4 is disposed horizontally. The height position (center position in the height direction) of the supply port 4a is preferably set at a height of 0.1H to 0.3H from the base 2a of the septic tank 2, where H is the height from the base 2a to the upper surface 2c.

[0027] A funnel 9 and a circulation pipe 10 are disposed above the raw water supply pipe 4a and in the upper part of the cylindrical tank 2d. The funnel 9 has a circular opening 9a, and its diameter increases toward the opening 9a. In the cylindrical tank 2d, the funnel 9 is installed with the opening 9a facing upward. The height of the opening 9a is preferably set at a position 0.8H higher than the base 2a relative to the tank height H.

[0028] Inner diameter of septic tank 2 φ a The inner diameter φ of the cylindrical partition wall 8 is not particularly limited, but is, for example, 100 to 300 cm. b is the inner diameter of the septic tank 2 a The opening dimension φ of the opening 9a of the funnel 9 is preferably 50% to 80% of the above. c is the inner diameter dimension φ of the cylindrical partition wall 8 b In particular, the inner diameter φ of the cylindrical partition wall 8 is preferably 50% to 80% of the above. b The inner diameter of the septic tank 2 is φ a and the opening dimension φ of the opening 9a of the funnel 9 is 60% to 80% of c The inner diameter of the cylindrical partition wall 8 is φ bIt is more preferable that the ratio is 60% to 80% of the above.

[0029] A groove-shaped recovery path 12 is provided around the entire periphery of the upper part of the cylindrical outer tank 2e. The recovery path 12 is connected to the discharge pipe 7. The treated water introduced into the recovery path 12 beyond the side wall 12a is discharged from the discharge pipe 7.

[0030] The lower inner surface of the cylindrical outer tank 2e forms an inclined surface 2f whose diameter decreases toward the bottom. The inclination angle of the inclined surface 2f in the height direction cross section of the septic tank 2 is, for example, 20 to 60 degrees. The lower end of the cylindrical partition wall 8 is positioned close to the inclined surface 2f. A sludge settling area is formed in this closely positioned inclined surface portion, where the sludge is concentrated and the treated water is separated. Furthermore, by positioning the lower end of the cylindrical partition wall 8 close to the inclined surface 2f, rapid forced settling of the sludge is possible. Note that it is preferable to adjust the distance between the lower end of the cylindrical partition wall 8 and the inclined surface 2f depending on the type and amount of sludge.

[0031] The activated sludge deposited at the bottom of the cylindrical outer tank 2e is discharged to the outside of the tank through a discharge pipe 11. The discharge pipe 11 is arranged with its discharge port 11a facing upward to facilitate the discharge of the activated sludge.

[0032] FIG. 3 is a top plan view of the inside of the septic tank. As shown in FIG. 3, the funnel 9, cylindrical partition wall 8, recovery channel 12, and septic tank 2 are arranged concentrically. The raw water supply pipe 4 and circulation pipe 10 penetrate the cylindrical side surface 2b of the septic tank 2 and the cylindrical partition wall 8 and are inserted into the cylindrical partition wall 8. In FIG. 3, the raw water supply pipe 4 and circulation pipe 10 are parallel to each other. The end of the raw water supply pipe 4 is arranged along the inner wall surface of the cylindrical partition wall 8. This arrangement allows the high-concentration oxygen water released from the supply port 4a to flow along the curved inner wall surface, generating a swirling flow in the cylindrical inner tank 2d. The water to be treated in the cylindrical inner tank 2d becomes relatively high in dissolved oxygen when mixed with this high-concentration oxygen water. Furthermore, the swirling flow agitates the water, further promoting the activity of aerobic microorganisms.

[0033] While a typical septic tank is equipped with an agitator inside the tank, which promotes the activity of aerobic microorganisms through agitation, the septic tank of the present invention uses a static mixer to produce oxygen-rich water and generates a swirling flow by releasing the oxygen-rich water, thereby improving the efficiency of the aerobic microbial treatment reaction without the need for a dynamic agitator.

[0034] A wastewater treatment method using the purifier 1 will now be described with reference to Fig. 4. Fig. 4 is a diagram illustrating the flow paths of the water to be treated and activated sludge in the septic tank 2. In Fig. 4, the shaded areas indicate areas with high concentrations of activated sludge, and the arrows indicate the circulation directions of the water to be treated and activated sludge.

[0035] In Fig. 4, V1 to V8 are valves for adjusting the flow paths and flow rates of raw water and circulating water, and F1 to F2 are flow meters. Valves V1 to V4 are provided in raw water supply pipe 4, valves V5 to V7 are provided in circulation pipe 10, and valve V8 is provided in discharge pipe 11. Note that discharge pipe 11 is connected to circulation pipe 10 midway. In the purification device 1 of Fig. 4, each of valves V1 to V8 is opened and closed based on the flow rate of raw water measured by flow meters F1 to F2, etc. The opening and closing of the valves may be performed automatically by a flow control device (not shown).

[0036] Raw water containing pollutants from which solids have been separated using, for example, a wedge wire screen is introduced into the purification device 1 of FIG. 4. It is preferable to measure the BOD and SS of the introduced raw water beforehand. For example, the raw water may contain a BOD of 800 mg / L or more, a chemical oxygen demand (hereinafter referred to as COD) of 300 mg / L or more, and a total nitrogen (hereinafter referred to as TN) of 40 mg / L or more. This device is also suitable for treating raw water containing a normal-hexane-extracted oil concentration of 50 mg / L or more.

[0037] A portion of the raw water supply pipe 4 is connected to the pump 3, and by operating the pump 3 with the valves V1 to V4 open, raw water is supplied into the septic tank 2. At this time, the raw water is agitated and mixed with air in the static mixer 6, and the resulting highly oxygenated water is released from the supply port 4a. The amount of air introduced from the air pipe 5 is adjusted, for example, based on the flow rate of the raw water.

[0038] As described above, the raw water supply pipe 4 is inserted into the septic tank 2 perpendicular to the height of the tank 2 and is positioned along the inner wall surface of the cylindrical partition wall 8 (see Figure 3). This allows the oxygen-rich water released from the supply port 4a to flow along the curve of the inner wall surface of the cylindrical partition wall 8, generating a swirling flow as shown in Figure 4. The swirling flow, with a relatively high dissolved oxygen content, slowly rises and comes into contact with aerobic microorganisms in the water being treated, causing the nitrification reaction, an aerobic microbial treatment reaction, to proceed. Some of the activated sludge produced by this reaction settles to the bottom of the septic tank 2. Meanwhile, the water being treated (water that has been treated once in the septic tank 2) and some of the activated sludge in the cylindrical inner tank 2d are introduced into the circulation pipe 10 through the funnel 9 as circulating water.

[0039] The circulation pipe 10 is connected to the raw water supply pipe 4 via the pump 3, and the circulating water passes through the static mixer 6 before being supplied again to the septic tank 2. The circulating water is circulated by operating the pump 3 with the valves V5 to V7 and V2 to V4 open. Because the circulating water contains aerobic microorganisms, returning this circulating water to the septic tank 2 can further promote the activity of the aerobic microorganisms. Furthermore, because the circulating water passes through the static mixer 6, it becomes highly oxygen-enriched water and is supplied again.

[0040] When circulating the circulating water, the circulating water and raw water may be mixed by opening the valve V1 of the raw water supply pipe 4. The flow rate of the raw water to be mixed is adjusted based on the measured values ​​of the flow meters F1 and F2, etc.

[0041] The oxygen-rich water based on the circulating water released from the supply port 4a again generates a swirling flow, allowing the aerobic microbial reaction to proceed efficiently in the cylindrical inner tank 2d. A portion of the water to be treated in the cylindrical inner tank 2d then flows upward through the opening 8a of the cylindrical partition wall 8 into the cylindrical outer tank 2e. In the cylindrical outer tank 2e, the supply of oxygen is cut off, and the aerobic microbial reaction ceases, causing the activated sludge to slowly settle and accumulate at the bottom. The treated water, purified by the settling of the activated sludge, overflows into the recovery channel 12. The upper section of the septic tank 2 is separated by the cylindrical partition wall 8, preventing the purified treated water from mixing with the water to be treated again. Finally, the treated water is discharged from the discharge pipe 7 and reused as toilet flushing water within the facility. It may also be discharged into a river or sewer, if necessary.

[0042] The activated sludge deposited at the bottom of the septic tank 2 is discharged from a discharge pipe 11 by a pump 3. This activated sludge may be discharged to the outside of the septic tank 2, or may be supplied to the septic tank 2 again.

[0043] The septic tank 2 contains 5,000 to 12,000 mg / L of activated sludge converted to solids, and as the nitrification reaction progresses, the pH and other properties of the water being treated decrease. The pH, oxidation-reduction potential (hereinafter referred to as ORP), and dissolved oxygen content (hereinafter referred to as DO) of the water being treated are measured using a treated water quality measuring device (not shown), and the amount of raw water supplied and the amount of water being treated circulated are determined based on these values. Specifically, the amount of air blown in is adjusted so that the ORP is maintained at +10 mV or higher in the aerobic reaction treatment section (cylindrical tank 2d) where the nitrification reaction occurs, and the water being treated is circulated.

[0044] In the case of treatment by the wastewater treatment method of the present invention, even if the raw water has a BOD of at least 800 mg / L or more and a T-N of 40 mg / L or more, the BOD of the treated water is usually extremely low, at 20 mg / L or less, and generally, operation is possible with a BOD of 10 mg / L or less as the water quality of the discharged water.

[0045] The purifying apparatus of the present invention is not limited to the embodiments shown in Figures 1 to 4. Figure 5 shows another embodiment of the purifying apparatus. Figure 5 is a vertical cross-sectional view of a septic tank 2'. The septic tank 2' in Figure 5 is similar to the septic tank 2 in Figure 2 except for the configuration of the cylindrical partition wall 8. In the septic tank 2 in Figure 2, the cylindrical partition wall 8 is a right cylinder with the same area on the upper and lower surfaces, whereas the cylindrical partition wall 8 in the septic tank 2' in Figure 5 is a truncated cone with the area of ​​the lower surface being larger than the area of ​​the upper surface.

[0046] As shown in FIG. 5, when the cylindrical partition wall 8 has a truncated cone shape, the surface area of ​​the liquid level A of the water to be treated in the cylindrical outer tank 2e is larger than when it has a right cylindrical shape (see FIG. 2). The larger the surface area of ​​the liquid level A, the faster the settling speed of activated sludge. Therefore, by making the cylindrical partition wall 8 have a truncated cone shape, the settling speed of activated sludge in the cylindrical outer tank 2e increases, and as a result, the wastewater treatment speed can be increased. Furthermore, when the cylindrical partition wall 8 has a truncated cone shape, the inner diameter of the cylindrical inner tank 2d decreases upward. This gradient makes it easier to maintain the swirling flow generated in the cylindrical inner tank 2d, allowing for efficient agitation in the cylindrical inner tank 2d. Furthermore, even when the inner diameter of the cylindrical partition wall 8 varies as shown in FIG. 5, it is preferable that the inner diameter dimension vary within a range of 50% to 80% of the inner diameter dimension of the septic tank 2'.

[0047] The wastewater treatment method of the present invention can be combined with conventional wastewater treatment methods. For example, by connecting an existing anaerobic denitrification tank to the purification apparatus of the present invention and supplying primary treated water treated by anaerobic microorganisms as raw water to the purification apparatus of the present invention, nitrification of the sludge load and denitrification and dephosphorization can be performed more effectively. [Industrial Applicability]

[0048] The purifying device of the present invention has a simple structure yet is excellent in treatment efficiency and energy saving, and can be used as a purifying device in facilities such as buildings and restaurants, for example. [Explanation of symbols]

[0049] 1 Purification equipment 2, 2' septic tank 2a Foundation 2b Cylindrical side 2c Top part 2d Cylindrical inner tank 2e Cylindrical outer tank 2f slope 3. Pump 4 Raw water supply pipe 4a Supply port 4b Air inlet 5 Air tube 6. Static Mixer 7 Outlet pipe 8 Cylindrical bulkhead 8a opening 9 funnel 9a opening 10 Circulation tube 11 Discharge pipe 12 Recovery Route

Claims

1. A purification device comprising: a cylindrical septic tank; a raw water supply pipe connected to a pump for supplying raw water to the septic tank by the pump's pressure; and a discharge pipe for discharging treated water purified by the action of aerobic microorganisms in the septic tank. an air inlet through which air is introduced is provided in the raw water supply pipe, and a static mixer is provided between the air inlet and the supply port of the raw water supply pipe; The raw water and the air are mixed by the static mixer and supplied to the septic tank, The septic tank has a cylindrical partition wall that divides a space within the septic tank, and the inside and outside of the cylindrical partition wall are connected through an opening at a lower end of the cylindrical partition wall, A purification device characterized in that the raw water supply pipe penetrates the cylindrical partition in a direction perpendicular to the height direction of the septic tank, is inserted into the interior of the cylindrical partition, and is arranged along the inner wall surface of the cylindrical partition.

2. The purification device has a circulation pipe that circulates the water to be treated in the septic tank outside the tank, and the circulation pipe is connected to the raw water supply pipe, and the water to be treated introduced into the circulation pipe has a circulation path that passes through the static mixer and is supplied again to the septic tank, The purification device described in claim 1, characterized in that a funnel is provided inside the cylindrical partition and above the raw water supply pipe for introducing the treated water in the purification tank into the circulation pipe, and the funnel is installed with its opening facing upward.

3. 3. The purification device according to claim 1, wherein the inner diameter of the cylindrical partition is 50% to 80% of the inner diameter of the purification tank.

4. 4. The purification device according to claim 1, wherein the cylindrical partition wall has a truncated cone shape.

Images