JP4249855B2 - Moving bed type filtration equipment using floating media - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a moving bed type filtration apparatus using a floating filter medium, and more particularly to a moving bed type filtration apparatus that performs filtration treatment of sewage using a floating filter medium having a specific gravity smaller than that of water.
[0002]
[Prior art]
As a moving bed type filtration apparatus using a floating filter medium having a specific gravity smaller than that of water, for example, a filter medium made of polystyrene foam, one described in JP-A-10-216756 is known. Normal moving bed filtration equipment supplies raw water from the upper part of the filtration tank filled with the floating filter medium in a downward flow, and takes out treated water from which turbidity has been removed by contact with the floating filter medium from the lower part of the filtration tank. ing. Washing of the floating filter medium that has captured the suspended matter is performed by a filter medium drawing process and a filter medium transfer process.
[0003]
The filter medium drawing process is a process of drawing a part of the filter medium in the filter tank through the filter medium inflow pipe to the filter medium storage tank provided in the upper part of the filter tank, and the filter medium transfer process transfers the filter medium extracted to the filter medium storage tank. It is a process of transferring to the bottom of the filtration tank through a tube. In this filter medium transfer step, the filter medium and turbidity are easily separated by the turbulent flow in the filter medium transfer pipe and transferred to the bottom of the filtration tank, and the filter medium separated from the turbidity at the bottom of the filter tank is filtered from the bottom of the filter tank. The suspended turbidity rising to the top of the tank is discharged from the bottom of the filtration tank along with the washing waste water. In addition, while performing the drawing-out process and the transfer process, inflow of raw water is continued in principle, and the filtration process is continuously performed.
[0004]
In the moving bed type filtration apparatus using such a floating filter medium, for example, 30 to 60 minutes is one cycle, the filtration process is 20 to 40 minutes, the filter medium drawing process is 1 to 2 minutes, and the filter medium transfer process is 10 to 20 Set each minute to drive.
[0005]
[Problems to be solved by the invention]
However, in the conventional filtration device, the rising filter medium and the falling water are switched in the filter medium inflow pipe in the filter medium drawing process, so that a relatively long time is required to draw a predetermined amount of the filter medium into the filter medium storage tank. Not only is it necessary, but turbidity is separated from the filter medium in the process of replacement of the filter medium and water, and the turbidity may be returned to the filtration tank together with water. In addition, since the filter medium storage tank is connected to the upper part of the filter tank via the filter medium inflow pipe, the height of the apparatus is increased, and the installation location is sometimes limited.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a moving bed type filtration device that can shorten the time required for the filter medium drawing step, improve the cleaning effect, and further reduce the size of the device.
[0007]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the moving bed type filtration apparatus using the floating filter medium of the present invention comprises a filtration tank having a raw water inflow part at the top and a treated water outflow part at the bottom, and a filter medium inflow valve at the top of the filtration tank. A filter medium storage tank connected via a filter medium inflow pipe, a filter medium suction part provided at the top of the filter medium storage tank, a transfer water pipe having a transfer water pump for supplying filter medium transfer water to the filter medium suction part, A filter media transfer device comprising a filter media transport pipe for transporting filter media transported water suctioning the filter media in the filter media storage tank to the bottom of the filter tank in the filter media suction section, and connected to the filter media storage tank The upper end opening of the inflow pipe protrudes into the filter medium storage tank and opens upward to be positioned above the bottom of the filter medium storage tank, and a drain pipe is connected to the bottom of the filter medium storage tank.
[0008]
Further, in the moving bed type filtration apparatus of the present invention, the opening height of the filter medium inflow pipe can be adjusted in the filter medium storage tank, and the washing drainage separation part for separating the filter medium and the cleaning wastewater at the bottom of the filter tank. And a grid presser for preventing expansion of the filter layer in the filtration tank.
[0009]
Moreover, when the expansion of the filter layer was detected in the filtration tank, a means for adjusting the filtration rate or starting the filter medium cleaning was provided, and the transfer of the filter medium from the filter medium storage tank to the filter tank via the transfer water pipe was completed. When the filter medium inflow valve is opened and the filter medium flows from the filter tank into the filter medium storage tank, the raw water inflow position is changed or the raw water inflow is stopped. It is characterized by providing means.
[0010]
In addition, air filter means is provided at the lower part of the filtration tank, the filter medium storage tank is provided at a side position of the filter tank, and the filter medium inflow pipe is bent downward from the top of the filter tank. It is connected to the lower part of the storage tank.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a system diagram showing a first embodiment of the moving bed filtration apparatus of the present invention. This moving bed type filtration apparatus has a filter tank 10 having a pair of upper and lower raw water inflow portions 11a, 11b in the upper part and a treated water outflow part 12 in the lower part, and a filter medium inflow valve 13 at the top of the filter tank 10. The filter medium storage tank 15 connected through the pipe 14, the ejector 16 that is a filter medium suction section provided at the top of the filter medium storage tank 15, and a part of the treated water drawn from the filter tank 10 as the filter medium transfer water. A transfer water pipe 20 having a transfer water pump 17 for supplying water to the ejector 16, a transfer valve 18, and a transfer water adjusting valve 19, and a filter medium transfer water that sucks and entrains the filter medium in the filter medium storage tank 15 by the ejector 16. A filter medium transfer pipe 23 having a filter medium transfer valve 22 for transfer to a washing drainage separator 21 provided at the bottom, and a drain connected to the bottom of the filter medium storage tank 15 via a drain valve 24 and a drain adjustment valve 25. And a tube 26.
[0012]
The raw water inflow portions 11a and 11b are connected to a raw water inflow pipe 31 having a raw water pump 29 and a flow meter 30 through supply switching valves 27a and 27b and check valves 28a and 28b. The cleaning / drainage separation unit 21 is provided with a plurality of inclined plates 32 for promoting separation of the filter medium and the cleaning / draining water, and the drainage of the cleaning / drainage having the cleaning / drainage valve 33 and the cleaning / drainage adjustment valve 34 at the bottom. A tube 35 is connected. Further, the treated water outflow pipe 36 connected to the treated water outflow section 12, the drainage pipe 26 and the washing drainage discharge pipe 35 are provided with overflow weirs 36a, 26a and 35a having predetermined heights, respectively. Further, from the upstream side of the transfer water adjustment valve 19 of the transfer water pipe 20, an extrusion water pipe 38 having an extrusion water adjustment valve 37 for injecting the filter medium extrusion water into the filter medium storage tank 15 is branched. Furthermore, a pressure gauge 39 is provided in the raw water inflow pipe 31. The other valves 40, 41, 42 and 43 are normally fully open.
[0013]
The upper end opening 14a of the filter medium inflow pipe 14 connected to the filter medium storage tank 15 protrudes into the filter medium storage tank 15 and opens upward, and is positioned at a predetermined height above the bottom of the filter medium storage tank. I have to. As described above, in the filter medium storage tank 15, the upper end opening 14 a of the filter medium inflow pipe 14 is opened upward from the bottom of the filter medium storage tank 15, and the drain pipe 26 is connected to the bottom of the filter medium storage tank 15. Moreover, the inflow of the filter medium from the filter tank 10 to the filter medium storage tank 15 can be performed smoothly.
[0014]
That is, when the filter medium inflow valve 13 and the drain valve 24 are opened to start the filter medium drawing process, the amount corresponding to the filter medium flowing from the filter tank 10 through the filter medium inflow valve 13 and into the filter medium storage tank 15 through the filter medium inflow pipe 14. Water flows through the drainage adjustment valve 25 and the drainage valve 24 adjusted to a predetermined opening degree and flows out from the drainage pipe 26 over the overflow weir 26a. The phenomenon of replacement with water does not occur. Moreover, since the upper end opening 14 a is provided above the bottom of the filter medium storage tank 15, the filter medium does not flow out from the drain pipe 26. Therefore, the flow of the filter medium into the filter medium storage tank 15 is smoothly performed, the filter medium drawing process can be completed in a short time, and the suspended matter separated from the filter medium is not returned to the filter tank 10.
[0015]
Furthermore, in the filter medium drawing process, when the amount of the filter medium in the filter medium storage tank 15 reaches the upper end opening 14a of the filter medium inflow pipe 14, no further filter medium can flow in due to the resistance between the filter medium. By forming the opening height of the portion 14a so as to be adjustable up and down, the amount of the filter medium withdrawn from the filtration tank 10 can be adjusted to an optimum amount according to the processing conditions. In addition, as a structure which can be adjusted up and down, the slide structure by a double tube, the expansion-contraction structure by a bellows tube, etc. are employable.
[0016]
In the filter medium transfer step, after the filter medium inflow valve 13 and the drainage valve 24 are closed, the transfer valve 18 and the filter medium transfer valve 22 are opened to operate the pump 17, and a part of the treated water flowing through the treated water outflow pipe 36 is transferred to the transfer water pipe. By supplying the transfer water from 20 to the ejector 16, the filter medium in the filter medium storage tank 15 is sucked into the ejector 16, and transferred to the washing / drainage separation unit 21 through the filter medium transfer pipe 23 together with the transfer water. At this time, a part of the water in the transfer water pipe 20 branches to the extruded water pipe 38, flows into the filter medium storage tank 15 as extruded water, and the filter medium is pushed out to the ejector 16, whereby the filter medium can be efficiently transferred. . The flow rate balance between the transfer water and the extrusion water can be performed by the transfer water adjustment valve 19 and the extrusion water adjustment valve 37.
[0017]
The washing waste water separation unit 21 separates the filter medium and turbidity that are easily separated by the action of turbulent flow in the filter medium transfer pipe 23, raises the filter medium into the filtration tank 10, and transfers the turbid substance. Water and a part of the treated water at the bottom of the filtration tank are discharged from the cleaning drainage pipe 35 as cleaning wastewater, and are provided to prevent the turbidity from rising to the filtration tank 10 together with the filter medium.
[0018]
In this cleaning / drainage separation unit 21, the substantial flow path length in the cleaning / drainage separation unit 21 is increased by the plurality of inclined plates 32, thereby increasing the residence time of the filter medium in the cleaning / drainage separation unit 21. The separation from turbidity is promoted. Further, the amount of discharged water from the washing drainage discharge pipe 35 is made larger than the amount of inflowing water from the filter medium transfer pipe 23, and a part of the treated water is allowed to flow into the washing drainage separation unit 21 from the filtration tank 10. Since a downward flow can be formed in the part 21, the ascending speed of the filter medium can be kept low.
[0019]
As a result, even when a filter medium having a very small specific gravity and a considerably high ascent rate is used, the separated suspended matter will not rise into the filtration tank 10 together with the filter medium and be taken into the treated water. It can be obtained stably.
[0020]
As shown in the sectional view of FIG. 2, the shape of the washing / drainage part 21 may be one provided with a baffle plate or porous plate 51 inside, or one provided with a screw member 52 as shown in FIG. 3. Further, as shown in FIG. 3, it is also effective to increase the flow rate of the treated water flowing from the filtration tank 10 by providing a throttle 53 in the upper part of the washing waste water separation unit 21, as shown in FIG. In addition, it is possible to adjust the inflow amount of the treated water by providing a regulating valve 54 in the upper part of the washing waste water separation unit 21.
[0021]
Adjustment of the amount of discharged water from the cleaning drainage discharge pipe 35 can be set by the position of the overflow weir 35a and the cleaning drainage adjustment valve 34. If the amount of drainage of the cleaning drainage is increased, the separation of turbidity is more reliably performed. Although it can be performed, since a part of the treated water is discharged as cleaning wastewater, if the amount of discharged water is excessively increased, the filtration efficiency is lowered. Therefore, by providing the washing waste water separation part 21 as described above, the ratio of the amount of treated water discharged as washing waste water can be reduced, and the filtration efficiency can be enhanced while obtaining a sufficient washing effect.
[0022]
In this embodiment, a grid presser 55 is provided above the treated water outflow portion 12 in the filtration tank 10 to prevent the filter layer from expanding. By providing such a grid retainer 55, it is possible to prevent the filter layer from reaching the vicinity of the treated water outflow portion 12, and it is possible to prevent turbidity that is not captured by the filter medium from leaking into the treated water.
[0023]
Further, a detection means for detecting the expansion of the filter layer is provided in the vicinity of the upper portion of the grid retainer 55, and when the detection means detects the expansion of the filter bed, the setting of the flow meter 30 is changed to reduce the raw water inflow amount. A means for reducing the filtration rate by reducing the flow rate, stopping the inflow of raw water, or starting the filter medium drawing process to open the filter medium inflow valve 13 for washing the filter medium, for example, a computer By providing such control means, it is possible to prevent turbidity from leaking into the treated water due to the expansion of the filter bed.
[0024]
That is, conventionally, the control of starting the cleaning of the filter medium is performed by periodically cleaning the filter medium with a timer or detecting an increase in the filtration resistance in the raw water supply unit. However, with the control by the timer, depending on the properties of the raw water, the filtration efficiency is reduced by the amount of treated water that is unnecessarily washed and discharged as washing wastewater. There was a risk of quality leaks. On the other hand, in the control for detecting the increase in filtration resistance, the filtration layer may expand despite the fact that the increase in filtration resistance is small, which may cause turbidity leakage.
[0025]
Therefore, by directly detecting the expansion of the filter layer, it is possible to start the cleaning of the filter medium at an optimal timing, to surely prevent the leakage of turbidity, and to improve the filtration efficiency compared to the conventional case. . In addition, what is necessary is just to start washing | cleaning of a filter medium by a timer, or to start washing | cleaning manually by an alarm etc., when reducing a filtration rate or stopping inflow of raw | natural water. Moreover, as a means for detecting the expansion of the filter layer, a device using buoyancy, an optical device, a device using ultrasonic waves, or the like can be used.
[0026]
Furthermore, the filter medium storage tank 15 and the transfer water pipe 23 are provided with means for detecting the presence or absence of the filter medium inside them, and when the detection means detects that there is no filter medium, that is, the transfer of the filter medium is completed. When the pump 17 is stopped, the pump 17 is stopped, and the transfer valve 18 and the filter medium transfer valve 22 are closed to end the filter medium transfer process, for example, a control means such as a computer is provided. Reduction and the amount of washing wastewater can be reduced.
[0027]
The time required for transferring the filter medium varies depending on the trapped state of turbidity, and the required time is not necessarily constant even when the same amount of filter medium is transferred. For this reason, in the past, the timer was set at a time slightly longer than the actual transfer time, so even after the transfer of the filter media was completed, the pump was operated and the power wasted wasted. It was a lot.
[0028]
Therefore, by directly detecting the end of the transfer of the filter medium and ending the filter medium transfer operation, it is possible to reduce power consumption and improve the filtration efficiency. Moreover, as a means for detecting the presence or absence of a filter medium, an optical device, a device using ultrasonic waves, or the like can be used.
[0029]
Further, with the start of the filter medium drawing process, the supply switching valves 27a and 27b are switched to open and close to change the raw water supply position from the raw water inflow part 11a during normal filtration operation to the raw water inflow part 11b located below. Since the filter medium rising from the inside of the filtration tank 10 toward the filter medium storage tank 15 is not stirred by the flow of the inflowing water, the trapped suspended matter can be raised while being held by the filter medium. That is, in the filter medium extraction step, raw water is allowed to flow from the lower raw water inflow portion 11b, whereby turbidity trapped by the filter medium can be sufficiently removed, and good treated water quality can be maintained. In addition, since the filter medium extraction process is completed in a short time due to the effect of installing the drain pipe 26, the same effect can be obtained even if the raw water inflow portion is only one place and the supply of raw water is stopped in the filter medium extraction process. I can expect.
[0030]
Moreover, it can also be set as the biofilm filtration apparatus which provided the aeration means in the lower part and filtration layer of the filtration tank 10, and added the purification | cleaning function by an aerobic biofilm. In the case of the filtration tank having the structure shown in this embodiment, an air vent is provided in the upper part of the filtration tank 10 through a screen that does not allow the filter medium to pass therethrough.
[0031]
FIG. 4 is a system diagram showing a second embodiment of the moving bed type filtration apparatus of the present invention. In the following description, the same components as those of the first embodiment are designated by the same reference numerals, and detailed description thereof is omitted.
[0032]
In order to reduce the height of the apparatus, the moving bed type filtration apparatus is provided with a filter medium storage tank 15 at a side position of the filter tank 10 and a filter medium inflow pipe 14 bent downward from the top of the filter tank 10. It connects with the lower part of the filter medium storage tank 15. FIG. Further, the upper part of the filtration tank 10 is opened, and a conical screen 61 for collecting the filter medium and an inverted conical dispersion plate 62 are provided in the upper part of the filtration tank, and an air diffuser connected to the compressor 63 in the lower part of the filtration tank. A device 64 is provided to function as a biofilm filtration device.
[0033]
During normal filtration operation, the raw water pump 29 and the compressor 63 are operated with all the valves closed, and the raw water is supplied into the filtration tank 10 as a downward flow from the raw water inflow portions 11a and 11b and diffused. Aeration from the device 64 is performed, and processing as a biofilm filtration device is performed. The treated water flows out from the treated water outflow portion 12 through the treated water outflow pipe 36 and the overflow weir 36a. At this time, the air bubbles rising in the filter layer are guided to the outer peripheral side of the tank by the dispersion plate 62, then pass through the screen 61 and exhausted above the filtration tank 10. Further, when the water level rises due to an aeration or an increase in filtration resistance, the water is discharged from the overflow pipe 65.
[0034]
The filter medium extraction step is performed by opening the filter medium inflow valve 13 and the drain valve 24. The filter medium collected by the screen 61 and floated to the upper center is the water in the filter medium storage tank 15, the drain valve 24, and the drain pipe. 26 and the filter medium storage tank from the upper end opening 14a opened to a predetermined position of the filter medium storage tank 15 through the filter medium inflow pipe 14 and the filter medium inflow valve 13 in a state accompanied by the water flow discharged through the overflow weir 26a. 15 flows in.
[0035]
Further, as another method for pulling out the filter medium, for example, the valves 67 and 68 are opened, the pump 17 is operated, and the water in the filter medium storage tank 15 is discharged. Furthermore, when the filtration tank 10 has a sealed structure that does not diffuse, the filter medium can be pushed out by the inflow water from the pump 29.
[0036]
The filter medium transfer process is performed by opening the shutoff valve 66, the transfer valve 18 and the filter medium transfer valve 22 and operating the pump 17 with the filter medium inflow valve 13 and the drain valve 24 closed. Thereby, the transfer water extracted from the bottom of the filtration tank 10 through the shutoff valve 66 is supplied to the ejector 16 through the transfer water pipe 20, and the filter medium is sucked from the filter medium storage tank 15 to filter the transfer medium transfer pipe 23. , And is transferred to a washing / drainage separation unit 21 provided at the bottom of the filtration tank 10. The flow rate balance between the transfer water and the extrusion water can be adjusted by the transfer water adjustment valve 19 and the extrusion water adjustment valve 37 in the same manner as described above. The turbidity separated from the filter medium by the cleaning / drainage separation unit 21 in this filtering medium transfer step is discharged from the lower part of the cleaning / drainage separation unit 21 through the cleaning / drainage discharge pipe 35 together with a part of the transfer water and the treated water.
[0037]
Thus, the formed bed moving type filtration apparatus of the present embodiment has the same function as that of the first embodiment, but the filter medium storage tank 15 is provided side by side at the side position of the filtration tank 10, The upper structure of the filtration device can be simplified, and the height of the device can be reduced. Furthermore, there is an advantage that adjustment and operability of each valve provided in the vicinity of the filter medium storage tank 15 are improved.
[0038]
In addition, although there is a concern that the installation area becomes large, since the filter medium storage tank 15 is smaller than the filtration tank 10 and the gantry can be simplified, the entire apparatus can be downsized.
[0039]
【The invention's effect】
As described above, according to the moving bed type filtration apparatus using the floating filter medium of the present invention, it is possible to shorten the time of the filter medium drawing process, and the turbidity is not returned to the filter tank, thereby increasing the filtration efficiency. be able to. Moreover, the filter medium and the suspended matter can be reliably separated in the filter medium transfer step, and clear treated water can be obtained stably. Furthermore, by starting the filter medium drawing process according to the state of the filter layer, it is possible to prevent the quality of the treated water from being deteriorated, and by ending the filter medium transfer process depending on the presence or absence of the filter medium, power costs are reduced and the amount of washing wastewater is reduced. Can be planned. Moreover, by arranging the filter medium storage tank at the side position of the filtration tank, the apparatus height can be lowered and the entire apparatus can be downsized.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a first embodiment of a moving bed type filtration apparatus of the present invention.
FIG. 2 is a cross-sectional view showing another example of the shape of the cleaning / drainage separation unit.
FIG. 3 is a cross-sectional view showing still another example of the shape of the cleaning / drainage separation unit.
FIG. 4 is a system diagram showing a second embodiment of the moving bed type filtration apparatus of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Filtration tank, 11a, 11b ... Raw water inflow part, 12 ... Treated water outflow part, 13 ... Filter medium inflow valve, 14 ... Filter medium inflow pipe, 14a ... Upper end opening part, 15 ... Filter medium storage tank, 16 ... Ejector, 17 ... Transfer water pump, 18 ... Transfer valve, 19 ... Transfer water adjustment valve, 20 ... Transfer water pipe, 21 ... Washing drain separator, 22 ... Filter medium transfer valve, 23 ... Filter medium transfer pipe, 24 ... Drain valve, 25 ... Drain adjustment valve , 26 ... drain pipe, 26 a ... overflow weir, 27 a and 27 b ... supply switching valve, 28 a and 28 b ... check valve, 29 ... raw water pump, 30 ... flow meter, 31 ... raw water inflow pipe, 32 ... inclined plate, 33 ... Washing drain valve, 34 ... Washing drain adjustment valve, 35 ... Washing drain discharge pipe, 35a ... Overflow weir, 36 ... Treated water outflow pipe, 36a ... Overflow weir, 37 ... Extrusion water regulation valve, 38 ... Extrusion water pipe, 39 ... Pressure gauge, 51 ... Perforated plate, 52 ... Screw member, 53 Throttle unit, 54 ... regulator, 55 ... grid presser, 61 ... screen, 62 ... distribution plate, 63 ... compressor, 64 ... air diffuser, 65 ... overflow pipe, 66 ... shutoff valve

Claims (9)

A filtration tank having a raw water inflow part at the top, a treated water outflow part at the bottom, a filter medium storage tank connected to the top of the filtration tank through a filter medium inflow pipe having a filter medium inflow valve, and a top of the filter medium storage tank The filter medium suction part provided, a transfer water pipe having a transfer water pump for feeding the filter medium transfer water to the filter medium suction part, and the filter medium transport water that sucks and entrains the filter medium in the filter medium storage tank in the filter medium suction part of the filter tank. a Utsuriyuka type filtration apparatus having a filter medium transfer tube for transferring the bottom, said top opening of the filter material filter material inflow tube connected to the reservoir, opens upward to be protruded to the filter material reservoir in the A floor moving type filtration apparatus using a floating filter medium, wherein the filter medium storage tank is positioned above the bottom of the filter medium storage tank, and a drain pipe is connected to the bottom of the filter medium storage tank. The moving bed type filtration apparatus using a floating filter medium according to claim 1, wherein the opening height of the filter medium inflow pipe is adjustable in the filter medium storage tank. The moving bed type filtration apparatus using the floating filter medium according to claim 1, wherein a washing drainage separation part for separating the filter medium and the washing drainage is provided at the bottom of the filtration tank. 2. The floor moving type filtration apparatus using the floating filter medium according to claim 1, wherein a grid presser for preventing expansion of the filter layer is provided in the filtration tank. The moving bed type filtration apparatus using the floating filter medium according to claim 1, wherein the filtration tank is provided with means for adjusting the filtration rate or starting the filter medium washing when the expansion of the filter layer is detected. The transfer using the floating filter medium according to claim 1, further comprising means for detecting that the transfer of the filter medium from the filter medium storage tank to the filter tank through the transfer water pipe is completed and terminating the filter medium transfer operation. Floor type filtration device. The floating filter medium according to claim 1, further comprising means for changing the raw water inflow position or stopping the flow of raw water when the filter medium inflow valve is opened to allow the filter medium to flow from the filter tank into the filter medium storage tank. The moving bed type filtration device used. The moving bed type filtration apparatus using the floating filter medium according to claim 1, wherein a diffuser is provided at a lower portion of the filtration tank. The filter medium storage tank is provided side by side in the filtration tank, and the filter medium inflow pipe is bent downward from the top of the filter tank and connected to the lower part of the filter medium storage tank. A moving bed type filtration apparatus using the floating filter medium according to claim 1.

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