Water purification treatment system using soft material sheet filter

Abstract

To provide improvement of an ability to retain sludge and maintain internal aerobic conditions when using microorganism-immobilization carriers to purify and treat water to be treated.SOLUTION: A water purification treatment system using a soft material sheet filter includes a plurality of microorganism-immobilizing carriers placed in a water tank to be treated and each of the microorganism-immobilizing carriers flows in the water to be treated to purify the water to be treated, a predetermined gap installed inside the water tank to be treated, a return channel that returns water to be treated after purification treatment to the water tank to be treated, and means for controlling the jetting of water to be treated through the return channel to the screen and microorganism-immobilizing carriers at predetermined pressure and flow rate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a water purification system using a filter medium made of a soft material. [Background technology]

[0002] Various methods are known for purifying and treating wastewater such as sewage, domestic wastewater, industrial wastewater, etc. For example, the following patent documents by the applicant propose a water purification treatment system and related techniques.

[0003] Patent Document 1 proposes a water purification treatment system that combines a fixed bed method and a fluidized bed method in biofilm treatment.

[0004] Patent Document 2 proposes an improvement to the microorganism-immobilizing carrier used in the activated sludge method. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-12369 [Patent Document 2] Patent No. 5641548 Summary of the Invention [Problem to be solved by the invention]

[0006] When using microorganism-immobilized carriers in biofilm processes or activated sludge processes, the carriers are required to have the ability to discharge the sludge that has accumulated in them. Conventionally, resin sponge materials and the like have been used as microorganism-immobilized carriers from the viewpoint of sludge retention.

[0007] While microorganism-immobilized carriers made of resin sponge material have the advantage of being able to hold a large amount of sludge, the sludge accumulated in the carrier is difficult to discharge, and over long-term use, the internal state of the carrier changes from an aerobic state to an anaerobic state, which reduces the number of aerobic microorganisms carried, and there is a risk of a decline in the treatment performance of the water to be treated. Therefore, there is a need for improvements to microorganism-immobilized carriers that can maintain an internal aerobic state for a long period of time while retaining the characteristic of being able to hold a large amount of sludge.

[0008] The object of this invention is to improve the purification capacity of water to be treated by maintaining the sludge retention capacity and the aerobic state inside the microorganism-immobilized carrier when the water to be treated is purified using the carrier. [Means for solving the problem]

[0009] [1] A water purification treatment system using a soft material filter medium, in which a plurality of microorganism-immobilized carriers are placed inside a water tank to be treated, and the plurality of microorganism-immobilized carriers flow in the water to be treated to purify the water, a screen having a predetermined gap provided inside the treated water tank; a return path for returning the treated water after purification to the treated water tank; a jet control means for blowing the treated water through the return passage onto the screen and the microorganism-immobilized carriers at a predetermined pressure and flow rate. A water purification treatment system using a filter medium made of soft material. [Effects of the Invention]

[0010] According to this invention, when the microorganism-immobilized carrier is used to purify water to be treated, the sludge retention capacity and the internal aerobic state can be maintained, thereby improving the purification capacity of the water to be treated. [Brief explanation of the drawings]

[0011] [Figure 1] 1A and 1B show an example of the configuration of a water purification treatment system according to an embodiment of the present invention, in which (a) is a plan view and (b) is an AA cross-sectional view. [Figure 2] 1A and 1B are perspective views of an example of a screen and a microorganism-immobilized carrier, respectively, used in the water purification treatment system of the present embodiment. [Figure 3] 1(a) to 1(e) are perspective views of other examples of the microorganism-immobilized carrier used in the water purification treatment system of this embodiment. [Figure 4] 1A and 1B are enlarged conceptual diagrams of a portion of the cells forming the porous structure of the microorganism-immobilized carrier, showing (a) a cell structure in which no annular membrane is formed on the inner peripheral wall of each cell, and (b) a cell structure in which an annular membrane is formed on the inner peripheral wall of each cell. [Figure 5] FIG. 1 shows enlarged reference photographs of a portion of a microorganism-immobilized carrier having cells with ring-shaped membranes, showing (a) the state of the cells before the sludge treatment biofilm adheres, and (b) the state of the cells after the sludge treatment biofilm adheres. [Figure 6] (a) and (b) are conceptual diagrams illustrating the state in which microorganism-immobilized carriers pass through a screen. [Figure 7] 7(a) shows an example of an aeration device used in the water purification treatment system of this embodiment, where (a) is a plan view showing an example of a perforated pipe type aeration device, (b) is a side view showing an example of the aeration pipe of FIG. 7(a), (c) is a side view showing another example of the aeration pipe of FIG. 7(a), (d) is a diagram showing an example of a dome type aeration device, and (e) is a side view of the aeration device of FIG. 7(d). [Figure 8] 2A and 2B are conceptual diagrams illustrating an example of water purification processing by the water purification processing system shown in FIG. 1, where (a) is a plan view and (b) is a cross-sectional view taken along the line B-B. [Figure 9] 1. FIG. 4 is a conceptual diagram illustrating another example of water purification treatment by the water purification treatment system shown in FIG. 1, where (a) is a plan view and (b) is a CC cross-sectional view. [Figure 10] FIG. 2 is a diagram showing the configuration of a test machine for the water purification treatment system of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] An example of an embodiment of the present invention will now be described with reference to the accompanying drawings.

[0013] The water purification treatment system of this embodiment is a water purification treatment system in which a plurality of microorganism-immobilized carriers are placed inside a water tank to be treated, and the plurality of microorganism-immobilized carriers flow within the water to be treated, thereby purifying the water to be treated, and is a system that performs water purification treatment using an activated sludge method, for example. In the example shown in Figure 1, the water purification treatment system 1 includes a water tank 2 to be treated, a screen 8, microorganism-immobilized carriers 9 (see Figures 2(b) and 3), and an aeration device 15.

[0014] The treated water tank 2 is a tank that stores and purifies water to be treated, such as domestic wastewater or industrial wastewater. The treated water tank 2 shown in Fig. 1 is connected to a treated water flow path 4 and a treated water flow path 6. The treated water 17 is introduced into the treated water flow path 4 from a raw water tank (not shown) by a treated water introduction pump 3 and flows into the treated water tank 2. After the treated water 17 in the treated water tank 2 has been purified by the activated sludge method, the treated water is introduced into the treated water flow path 6 and stored in a treated water tank (not shown).

[0015] The screen 8 is a component for discharging sludge accumulated inside the microorganism-immobilized carriers 9 when the microorganism-immobilized carriers 9 on which a biofilm has formed are flowing in the water to be treated 17, and is installed so as to be immersed in the water to be treated 17 stored in the water to be treated tank 2. As shown in FIG. 2(a), the screen 8 is composed of a plurality of rod-shaped bodies 8a of a predetermined height arranged at equal intervals with predetermined gaps 8b between them. The gaps 8b are determined in accordance with the sizes of the various microorganism-immobilized carriers 9.

[0016] The microorganism-immobilized carrier 9 is a filter medium made of a soft material, which supports aerobic microorganisms in the activated sludge in the treated water tank 2. The microorganism-immobilized carrier 9 is made of a porous foam and can be manufactured by processing a conventionally known synthetic resin such as water-swellable polyurethane foam, a sponge, or the like. In this embodiment, a foam 10 made of a synthetic sponge such as a urethane sponge is processed to form microorganism-immobilized carriers 9a-9c having a cubic structure of 10 mm x 10 mm x 10 mm as shown in Figures 2(b), 3(a), and 3(b), and microorganism-immobilized carriers 9d-9f having a rectangular parallelepiped structure as shown in Figures 3(c)-(e).

[0017] The shape of the microorganism immobilization carriers 9b-9f made of synthetic sponge is not limited to a cube or rectangular parallelepiped, and various other three-dimensional structures such as polygonal cylinders, cylinders, and spheres can be used, as long as a hollow portion described below can be formed inside the carriers.

[0018] As for the material of the microorganism-immobilized carrier, in addition to the synthetic sponge used in this embodiment, a resin sponge that becomes gel-like when swollen can also be used.

[0019] The number of cells forming the porous structure of the microorganism-immobilizing carriers 9a-9f is preferably 10-50 per 25 mm. If the number of cells exceeds 50, the carrier becomes fine-grained and is easy to support aerobic microorganisms, but is prone to wear. On the other hand, if the number of cells is less than 10, the carrier becomes coarsely foamed and is difficult to support aerobic microorganisms.

[0020] The microorganism-immobilized carriers 9b-9f of this embodiment are each made of the above-mentioned three-dimensional structure, and each have a plurality of openings formed on the surface of the three-dimensional structure. At least two of these openings are connected to form a cavity that runs through the interior of the three-dimensional structure.

[0021] In the form shown in Figure 3(a), openings 12, 12 with a diameter of 4 mm are provided at the center of the front surface 10a and back surface 10b of a cubic-shaped foam 10, and a cylindrical hollow portion 11a with a length of 10 mm is formed inside the foam 10, passing through the center of gravity G of the foam 10 and connecting the openings 12, 12.

[0022] In the form shown in Figure 3(b), openings 12, 12 with a diameter of 4 mm are provided at the center of the front surface 10a and back surface 10b of the cubic foam 10, and a cylindrical cavity 11a with a length of 10 mm is formed inside the foam 10, passing through the center of gravity G of the foam 10 and connecting the openings 12, 12.

[0023] In addition, openings 12, 12 with a diameter of 4 mm are provided at the center of the upper surface 10c and lower surface 10d of the foam 10, and a cylindrical hollow portion 11b with a length of 10 mm is formed inside the foam 10, passing through the center of gravity G of the foam 10 and connecting the openings 12, 12.

[0024] In the form shown in Figure 3(c), openings 12, 12 are provided at the center of the front surface 10a and back surface 10b of the rectangular parallelepiped foam 10, and a cylindrical hollow portion 11c that passes through the center of gravity G of the foam 10 and connects the openings 12, 12 is formed inside the foam 10.

[0025] In the embodiment shown in Figure 3(d), openings 12, 12 are provided at the center of the front surface 10a and back surface 10b of the rectangular parallelepiped foam 10, and a cylindrical hollow portion 11c is formed inside the foam 10, passing through the center of gravity G of the foam 10 and connecting the openings 12, 12.

[0026] In addition, openings 12, 12 are provided at the center of the left side surface 10f and right side surface 10e of the foam 10, and a cylindrical cavity 11d that passes through the center of gravity G of the foam 10 and connects the openings 12, 12 is formed inside the foam 10.

[0027] In the form shown in Figure 3(e), openings 12, 12 are provided at the center of the front 10a and right side 10e of the rectangular parallelepiped foam 10, and an L-shaped cavity 11e that passes through the center of gravity G of the foam 10 and connects the openings 12, 12 is formed inside the foam 10.

[0028] In all of the examples shown in Fig. 3, a cavity connecting openings formed on different surfaces of the three-dimensional structure passes through the interior of the three-dimensional structure. However, the present invention is not limited to such a structure, and for example, a structure may be adopted in which two openings are formed on one surface of the three-dimensional structure, and a cavity connecting the two openings passes through the center of gravity of the three-dimensional structure and passes through the interior of the three-dimensional structure.

[0029] Cavities 11a-11e, which connect at least two of the multiple openings formed on the surface of the three-dimensional structure and pass through the interior of the three-dimensional structure, serve to discharge sludge remaining inside the microorganism-immobilized carriers 9b-9f.

[0030] Figure 4(a) shows one form of the cell wall structure that forms the porous structure of the microorganism-immobilized carrier 9b in this embodiment. In the structure shown in Figure 4(a), each cell 13 is hexagonal. A sludge treatment biofilm is formed on the inner peripheral wall surface of each cell 13 of this hexagonal wall structure, and aerobic microorganisms are supported.

[0031] The shape of each cell 13 of the wall structure is not limited to the hexagonal shape shown in Figure 4(a), but can be a wall structure consisting of various shapes such as a polygonal shape such as a triangle, a quadrilateral (square, rectangle, diamond), a circle, or an ellipse.

[0032] It is also possible to have a structure in which an annular membrane is formed on the inner peripheral walls of the cells that form the wall structure having the various shapes described above, i.e., on the inner peripheral walls of the cells that form the porous structure of the foam.

[0033] 4(b) is a diagram showing a structure in which an annular membrane 14 is formed on the inner peripheral wall 13a of each cell forming the porous structure of the microorganism-immobilized carriers 9b-9e of this embodiment. In the example of FIG. 4(b), an annular membrane 14 is formed on the inner peripheral wall surface 13a of each cell 13 of the hexagonal wall structure described in FIG. 4(a). The annular membrane 14 can be formed on the inner peripheral wall 13a by utilizing burrs generated during the manufacturing process of the foam. The annular membrane 14 is formed in order to increase the number of aerobic microorganisms to be supported.

[0034] Figure 5 is a reference photograph showing an enlarged view of a portion of a microorganism-immobilized carrier in which a ring-shaped membrane is formed on the inner peripheral wall of a cell that forms the porous structure of the foam of a three-dimensional structure (12 mm x 12 mm x 12 mm) that connects two openings formed on the surface of the three-dimensional structure and has a cavity (4 mm in diameter and 12 mm in length) that passes through the interior of the three-dimensional structure. The number of cells is 1 per 25 mm.

[0035] Figure 5(a) shows the state of the cells before the sludge treatment biofilm attaches, with a thin, web-like, annular film formed on the inner circumferential wall of each cell that forms the wall structure.

[0036] Figure 5(b) is a photograph showing the state after sludge treatment biofilm has adhered to the thin, web-like annular film formed on the inner circumferential wall of each cell shown in Figure 5(a). It shows that the sludge treatment biofilm has formed over the entire inner circumferential wall (thin annular film) of each cell while maintaining the air and water holes.

[0037] The treated water tank is connected to a treated water return line 7 that returns a portion of the treated water to the treated water tank 2. A portion of the treated water is introduced from the treated water tank into the treated water return line 7 by a treated water introduction pump 5 and flows into the treated water tank 2.

[0038] The terminal end of the treated water return channel 7 in the treated water tank 2 faces the screen 8 so that the inflowing treated water can pass through the gaps 8b of the screen 8.

[0039] In addition, the water purification treatment system 1 of this embodiment is equipped with a jet control means (not shown) consisting of a computer that sprays treated water at a predetermined pressure and flow rate through the treated water return path 7 onto the screen 8 and the microorganism immobilization carriers 9 (9a-9f) near the screen 8.

[0040] The jet control means controls the treated water introduction pump 5 so that the treated water is sprayed onto the screen 8 and the microorganism-immobilized carriers 9a near the screen 8 flowing through the water to be treated 17, at a pressure and flow rate that allows the microorganism-immobilized carriers 9a, which are cubic structures of 10 mm × 10 mm × 10 mm as shown in FIG. 2(b) near the screen 8, to pass through 10 mm gaps 8b in the screen 8 as shown in FIG. 6, for example.

[0041] When treated water hits the microorganism-immobilized carriers 9a flowing in the water to be treated 17 near the screen 8, the microorganism-immobilized carriers 9a move in a direction that passes through the gaps 8b in the screen 8. At this time, as shown in Figure 6(a), if the opposing surfaces of the microorganism-immobilized carriers 9a (the front and back, right and left sides, or top and bottom of the foam 10) are parallel to the height direction of the rod-shaped bodies 8 of the screen 8, the microorganism-immobilized carriers 9a can pass through the gaps 8b in the screen 8.

[0042] On the other hand, as shown in Figure 6(b), when the opposing surfaces of the microorganism-immobilized carriers 9a are not parallel to the height direction of the rod-shaped bodies 8a of the screen 8 but are tilted, a portion of the microorganism-immobilized carriers 9a is pressed against the rod-shaped bodies 8a of the screen 8. Because the microorganism-immobilized carriers 9a are formed from a foam 10 made of synthetic sponge, the microorganism-immobilized carriers 9a pressed against the rod-shaped bodies 8a contract and deform in the direction of arrow 18a due to the treated water and rod-shaped bodies 8a being sprayed against them, allowing them to pass through the gaps 8b. By contracting and deforming in the direction of arrow 18a when passing through the gaps 8b, an external force equivalent to that exerted when kneading a sponge is applied to the microorganism-immobilized carriers 9a, and the sludge accumulated inside can be effectively discharged.

[0043] The aeration device 15 is a means for aerating the water to be treated 17 stored in the water tank 2. In this embodiment, a plurality of individually controlled aeration devices 15 are arranged at the bottom of the water tank 2 from the upstream side (raw water tank side) to the downstream side (treated water tank side). The aeration devices 15 are connected to an air supply pipe 18, and compressed air supplied from a blower 19 is supplied to the aeration devices 15 by controlling the opening and closing of a control valve, and aerates the water to be treated 17 via the aeration devices 15.

[0044] The air diffuser 15 may be any of a variety of conventionally known types, such as the porous pipe type air diffuser of FIG. 7(a) having an air diffuser tube that discharges fine bubbles from openings on the entire surface as shown in FIG. 7(b), the porous pipe type air diffuser of FIG. 7(a) having an air diffuser tube that discharges fine bubbles from openings that open downward as shown in FIG. 7(c), or the flat-plate type air diffuser of FIG. 7(d) having a dome-shaped air diffuser tube made of a membrane member as shown in FIG. 7(e).

[0045] In addition, each aeration device 4 is connected to an air supply pipe 13, and compressed air supplied from the compressed air supply device 12 is introduced into the air supply pipe 13 and the aeration device 4 by opening and closing valves 9b and 9c, and aerates the water to be treated 22 via the aeration device 4, or sends the compressed air to the purification treatment unit 3.

[0046] In this embodiment, air diffusion devices 15a-15d, each consisting of a plurality of air diffusion pipes, are arranged from the upstream side (raw water tank side) to the downstream side (treated water tank side).

[0047] By individually controlling each air diffuser 15, opening the control valves of the air diffusers 15a-15b shown in FIG. 1 and closing the control valves of the air diffusers 15a-15b and the adjacent air diffusers 15c-15d, an upward flow is generated in the operating air diffusers 15a-15b and a downward flow is generated in the stopped air diffusers 15c-15d, causing the microorganism-immobilizing carriers 9 (9a-9f) in the treated water 17 to flow.

[0048] The process of controlling the air diffusion of adjacent air diffusers 15 so that one is diffusing air while the other is stopping the air diffusion operation is performed by an air diffusion control means (not shown) made up of a computer.

[0049] When the upward and downward flows are generated and the microorganism-immobilized carriers 9 (9a-9f) are flowing through the water to be treated 17, the jet flow control means controls the treated water introduction pump 5 to cause part of the treated water to flow into the water to be treated tank 2 through the return path 7. As a result, the microorganism-immobilized carriers 9 (9a-9f) pass through the gaps 8b of the screen 8, but most of the microorganism-immobilized carriers 9 (9a-9f) contract and deform in the direction of the arrow 18a shown in Figure 6(b), and therefore, they pass through the gaps 8b while effectively discharging the sludge that has accumulated inside.

[0050] In the water purification treatment system 1 of this embodiment, as shown in Fig. 1, a plurality of aeration units 16, each consisting of a plurality of aeration devices 15 as one unit, are provided at the bottom of the water tank 2 to be treated. In the example shown in Fig. 1, aeration unit 16a is configured by combining aeration devices 15a and 15b as one unit, and aeration unit 16b is configured by combining aeration devices 15b and 15d as one unit.

[0051] When each aeration unit 16 is controlled individually, the control valve of the aeration device 15a constituting the aeration unit 16a and the control valve of the aeration device 15b constituting the aeration unit 16b are opened, and the control valve of the aeration device 15c and the control valve of the aeration device 15d are closed, as shown in FIG. 8(b), an upward flow indicated by the arrow 18b is generated relative to the screen 8 in the aeration device 15a and the aeration device 15b, and a downward flow indicated by the arrow 18b is generated relative to the screen 8 in the aeration device 15c and the aeration device 15d, causing the microorganism-immobilized carriers 9 (9a-9f) in the water to be treated 17 to flow in the direction of the arrow 18b.

[0052] In this state, when the jet flow control means controls the treated water introduction pump 5 to cause a portion of the treated water to flow into the treated water tank 2 in the direction of arrow 18c through the return path 7, the microorganism-immobilized carriers 9 (9a-9f) pass through the gaps 8b of the screen 8, but most of the microorganism-immobilized carriers 9 (9a-9f) contract and deform in the direction of arrow 18a shown in Figure 6(b), so that the sludge accumulated inside is effectively discharged as the carriers pass through the gaps 8b. In addition, a downward flow is generated against the screen 8, which has the effect of cleaning the screen 8 by peeling off dirt adhering to the rod-shaped bodies 8a of the screen 8.

[0053] Furthermore, when each aeration unit 16 is controlled individually, the control valve of the aeration device 15c constituting the aeration unit 16a and the control valve of the aeration device 15d constituting the aeration unit 16b are opened, and the control valve of the aeration device 15a and the control valve of the aeration device 15b are closed, as shown in FIG. 9(b), an upward flow indicated by arrow 18d is generated relative to the screen 8 in the aeration device 15c and the aeration device 15d, and a downward flow indicated by arrow 18d is generated relative to the screen 8 in the aeration device 15a and the aeration device 15b, causing the microorganism-immobilized carriers 9 (9a-9f) in the water to be treated 17 to flow in the direction of arrow 18d.

[0054] In this state, when the jet flow control means controls the treated water introduction pump 5 to cause a portion of the treated water to flow into the treated water tank 2 in the direction of arrow 18c through the return path 7, the microorganism-immobilized carriers 9 (9a-9f) pass through the gaps 8b of the screen 8, but most of the microorganism-immobilized carriers 9 (9a-9f) contract and deform in the direction of arrow 18a shown in Figure 6(b), so that the microorganism-immobilized carriers 9 pass through the gaps 8b while effectively discharging the sludge that has accumulated inside. In addition, an upward flow is generated relative to the screen 8, which has the effect of cleaning the screen 8 by peeling off dirt adhering to the rod-shaped bodies 8a of the screen 8.

[0055] [Test example] In order to compare the difference between the amount of sludge adsorbed and the amount of sludge removed by the microorganism-immobilized carriers in the water purification treatment system of this embodiment, the following sludge adsorption and removal test was carried out.

[0056] (1) Experimental aircraft The experimental water purification system 1A shown in Figure 10 was equipped with a water treatment tank 2, a screen 8, microorganism immobilization carriers (flow carriers) 9, an aeration device 15e, a circulating water storage vessel 20, and an overflow settling tank 22.

[0057] The tank 2 for water to be treated is a tank with a volume of 30 L, in which the water to be treated 17 is stored, a screen 8 is installed so as to be immersed in the water to be treated 17, and a large number of microorganism-immobilized carriers 9 are placed. In addition, a partition member 24 such as a punched metal is provided on the downstream side (right side in the figure) of the tank 2 for water to be treated, and the water to be treated 17 can pass through the partition member 24, but the microorganism-immobilized carriers 9 cannot.

[0058] The microorganism-immobilized carriers 9 are the carriers described above, and four types of carrier groups were prepared, each having been used for water purification treatment for 3, 5, 7, and 10 years.

[0059] The air diffuser 15e is disposed at the bottom of the water tank 2, and is connected to a blower 19 via an air pipe (aeration pipe) 18a.

[0060] The circulating water storage vessel 20 is a vessel for storing treated water 21 obtained after water purification treatment of the water to be treated 17. Two treated water return lines 7 are provided in the circulating water storage vessel 20. One treated water return line 7 is connected to a submersible pump 23 and its terminal end faces a screen 8. The other treated water circulation line 7 is connected to an overflow settling tank 22.

[0061] The overflow settling tank 22 is disposed downstream of the tank 2 for water to be treated, and serves to filter sludge contained in the circulating water (treated water) 21 flowing in from the tank 2 for water to be treated.

[0062] (2) Comparison For comparison, a water purification treatment system 1A shown in Fig. 10 was prepared without the screen 8 and circulating water storage vessel 20. Therefore, the comparison system only aerates the water 17 to be treated.

[0063] (3) Test Contents In both the experimental machine and the comparison model, the blower 19 is operated to supply compressed air to the air diffuser 15e in the direction of arrow 25 to aerate the water to be treated 17. In the experimental machine, the submersible pump 23 is also operated to circulate the circulating water 21 in the direction of arrow 26 and to spray the circulating water 21 onto the screen 8 in the direction of arrow 27.

[0064] Under these conditions, the sludge adsorption and detachment over time were checked for the experimental unit and the comparison unit. The results are shown in Tables 1 and 2.

[0065] [Table 1]

[0066] [Table 2]

[0067] (4) Test results and considerations As can be seen from Tables 1 and 2, the sludge reduction rate in the microorganism-immobilized carriers 9 in the test machine decreased over time compared to the control. This result is presumably due to the sludge in the microorganism-immobilized carriers 9 being peeled off by the screen 8 over time.

[0068] It was also confirmed that the amount of sludge adhesion in the overflow settling tank 22 increased over time in the test machine compared to the control. This result is presumably due to the sludge in the microorganism-immobilized carriers 9 that was detached by the screen 8 flowing into the overflow settling tank 22.

[0069] From the results of this experiment, it was confirmed that the water purification treatment system 1 of this embodiment has the effect of removing sludge from the microorganism-immobilized carriers 9 by the screen 8.

[0070] As described above, in this embodiment, by employing a screen 8 having a predetermined gap 8b in the water tank 2 and a jet control means for spraying treated water onto the screen 8 and the microorganism-immobilized carriers 9 (9a-9f) flowing near the screen 8 through the treated water return path 7, the microorganism-immobilized carriers 9 (9a-9f) contract when passing through the gaps 8b of the screen 8, and sludge accumulated inside is discharged. Therefore, the aerobic state inside the microorganism-immobilized carriers and their inherent sludge-retaining capacity are maintained for a long period of time, and as a result, the sludge purification treatment capacity is maintained for a long period of time. [Explanation of symbols]

[0071] 1. Water purification treatment system 2. Treated water tank 3. Treated water introduction pump 4. Treated water flow path 5 Treated water introduction pump 6 Treated water flow path 7 Treated water return channel 8 screens 8a Rod-shaped body 8b eye width 9(9a-9f) Microorganism immobilization carrier 10. Foam 10a Foam front 10b foam back 10c Top of foam 10d foam underside 10e foam right side 10f Left side of foam 11a-11e Cavity 12 Opening 13 cells 13a Inner wall of cell 14 Annular membrane 15a-15d Air diffuser 16a-16b Aeration unit 17 Untreated water 18 Air pipe 19 Blower 20 Circulating water storage container 21 Circulating water 22 Overflow settling tank 23 Submersible Pump 24 Partition member

Claims

1. A water purification treatment system using a soft material filter medium, in which a plurality of microorganism-immobilized carriers are placed in a water tank to be treated, and the plurality of microorganism-immobilized carriers flow in the water to be treated to purify the water to be treated, A screen having a predetermined gap provided inside the treated water tank; A return passage for returning the treated water after purification to the treated water tank; a jet control means for blowing the treated water through the return passage against the screen and the microorganism-immobilized carriers at a predetermined pressure and flow rate. A water purification treatment system using a soft material filter medium.

2. A plurality of air diffusers are further provided inside the treated water tank, The jet control means blows the treated water onto the screen and the microorganism-immobilizing carriers while an upward flow or a downward flow of the treated water is generated by the individual aeration control processing of each aeration device.

2. A water purification treatment system using the soft material filter medium according to claim 1.

3. A plurality of aeration units each having a plurality of aeration devices as one unit are further provided inside the treated water tank, Each air diffusion unit is controlled so that, when one of the plurality of air diffusion devices constituting each air diffusion unit is performing an air diffusion operation, the other air diffusion device is stopped, The jet control means blows the treated water onto the screen and the microorganism-immobilizing carriers while an upward flow or a downward flow of the treated water is generated by the aeration operation of the aeration device.

2. A water purification treatment system using the soft material filter medium according to claim 1.

4. The jet flow control means controls the pressure and flow rate of the treated water so that the microorganism-immobilized carriers can pass through the gaps in the screen. A water purification treatment system using the soft material filter medium according to any one of claims 1 to 3.

5. The microorganism-immobilizing carrier has a cavity that connects at least two of a plurality of openings formed on the surface of a three-dimensional structure made of a porous foam and passes through the inside of the three-dimensional structure. A water purification treatment system using the soft material filter medium according to any one of claims 1 to 3.

6. The microorganism-immobilizing carrier has a cavity that connects at least two of a plurality of openings formed on the surface of a three-dimensional structure made of a porous foam and passes through the inside of the three-dimensional structure.

5. A water purification treatment system using the soft material filter medium according to claim 4.

7. The cavity passes through the center of gravity of the three-dimensional structure.

6. A water purification treatment system using the soft material filter medium according to claim 5.

8. The cavity passes through the center of gravity of the three-dimensional structure. A water purification treatment system using the soft material filter medium according to claim 6.

9. A ring-shaped membrane was formed on the inner peripheral wall of the cells forming the porous structure of the foam. A water purification treatment system using the soft material filter medium according to claim 7.

10. A ring-shaped membrane was formed on the inner peripheral wall of the cells forming the porous structure of the foam. A water purification treatment system using the soft material filter medium according to claim 8.

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