Recovery device and treatment system

Abstract

To realize a technique of recovering a biofilm included in water to be treated.SOLUTION: The recovery device (10) comprises a treatment tank (11) treating a liquid to be treated, a recovery part (13) provided in a manner of partitioning the inside of the treatment tank (11) to capture the recovered material present in the liquid to be treated, an inflow part (12) for a liquid to be treated, allowing the liquid to be treated to flow into the treatment tank (11), a treated liquid discharge part (14) discharging the liquid to be treated having passed through the recovery part (13), and a siphon tube (15) for discharging the liquid present in the treatment tank (11) by a siphon mechanism when the recovery part (13) is clogged by the recovered material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a recovery device and a processing system. [Background technology]

[0002] A method for removing nitrogen from wastewater containing high concentrations of nitrogen using anammox bacteria is known. The method using anammox bacteria (anammox reaction) utilizes the reaction in which anammox bacteria couple nitrite and ammonia to generate nitrogen gas. When the inorganic nitrogen in the wastewater to be treated is only in the form of ammonia, nitrogen removal can be achieved by simultaneously inducing the ammonia oxidation reaction and the anammox reaction in an aerated treatment tank. Furthermore, when the wastewater to be treated also contains organic carbon, nitrogen removal can also be achieved by simultaneously inducing the ammonia oxidation reaction, the anammox reaction, and the denitrification reaction in a similarly aerated treatment tank. Nitrogen removal methods using anammox bacteria are expected to reduce the aeration power required for nitrogen removal and the consumption of organic matter.

[0003] However, because anammox bacteria are autotrophic bacteria, their growth rate is very slow, with a doubling time estimated at several days. Therefore, it is necessary to secure a sufficient amount of anammox bacteria for treatment. Biofilms containing high concentrations of anammox bacteria can form in the treatment tank. Biofilms that adhere to structures in the treatment tank can peel off and become floating biofilms, and may even become granular. Regardless of whether they are attached or floating, retaining these in the treatment tank enables efficient nitrogen removal treatment.

[0004] When wastewater to be treated contains ammonia nitrogen and organic carbon and nitrogen is removed by simultaneously causing ammonia oxidation, anammox, and denitrification reactions, a large amount of sludge is generated due to the proliferation of heterotrophic bacteria. To prevent a decrease in wastewater treatment efficiency due to the accumulation of sludge contained in the wastewater or generated during treatment in the aeration tank where the wastewater is treated, the sludge must be periodically removed from the aeration tank. However, if suspended anammox biofilms (hereinafter referred to as biofilms) or granules are present in the aeration tank, the removed sludge will also contain the biofilms or granules. Therefore, to prevent a decrease in the amount of anammox bacteria in the aeration tank due to sludge removal, it is desirable to recover the biofilms and granules from the removed sludge and return them to the aeration tank.

[0005] Patent Document 1 describes a granule recovery device that recovers granules, which are clumps of microorganisms that have flowed out of a tank that stores water to be treated, using multiple filters, changes the flow of water by opening and closing a timer-controlled valve, and returns the recovered granules to the tank. Patent Document 2 describes a technology for removing target substances that have adhered to a filter material in a water purification treatment device that filters raw water by backwashing the filter material with water, although the purpose is different from recovering useful substances in the treated water. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2017-131821 [Patent Document 2] WO2017 / 086411 Summary of the Invention [Problem to be solved by the invention]

[0007] The technology described in Patent Document 1 can recover granules and return them to the treatment tank, but has problems in that the filter structure and timer equipment are complicated and the timer control is cumbersome. Also, the technology described in Patent Document 2 has a complicated device structure and is not designed to treat wastewater containing sludge, making it difficult to use for recovering useful substances from wastewater.

[0008] One aspect of the present invention has been made to solve the above-mentioned problems, and its purpose is to realize a technology for recovering biofilm contained in water to be treated. [Means for solving the problem]

[0009] In order to solve the above problems, one embodiment of the recovery device of the present invention is a recovery device that recovers recovered materials in a treated liquid, and includes a treatment tank that treats the treated liquid, a recovery section that is arranged to divide the treatment tank into upper and lower or left and right sections and captures the recovered materials in the treated liquid that has passed through the recovery section, a treated liquid inlet section that is arranged below or upstream of the recovery section in the treatment tank and allows the treated liquid to flow into the treatment tank, a treated liquid discharge section that is arranged above or downstream of the recovery section in the treatment tank and discharges the treated liquid that has passed through the recovery section, and a siphon pipe that is connected below or upstream of the recovery section in the treatment tank and discharges the liquid in the treatment tank using a siphon mechanism if the recovery section is blocked by the recovered materials.

[0010] Furthermore, a treatment system according to one aspect of the present invention is a treatment system for treating wastewater, and includes an aeration tank that supplies oxygen to the wastewater and wastewater to be treated, which contains microorganisms that decompose the nitrogen components in the wastewater, and a recovery device according to one aspect of the present invention that recovers recovered material from the treated liquid, which contains a portion of the sediment in the wastewater to be treated and is withdrawn from the aeration tank. [Effects of the Invention]

[0011] According to one aspect of the present invention, a technique for recovering biofilm contained in water to be treated can be realized. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing an overview of a recovery device according to an embodiment of the present invention. [Figure 2] 1 is a diagram illustrating an outline of a processing system including a recovery device according to an embodiment of the present invention. [Figure 3] FIG. 1 is a diagram showing an overview of a first modified example of a recovery device according to an embodiment of the present invention. [Figure 4] FIG. 10 is a diagram showing an outline of a second modified example of a recovery device according to an embodiment of the present invention. [Figure 5] FIG. 1 is a graph showing the relationship between biofilm size and anammox bacteria concentration. [Figure 6] FIG. 10 is a graph showing the results of measuring the weight of biofilms in the influent to be treated in the recovery device and the siphon discharge liquid discharged from the siphon tube. DETAILED DESCRIPTION OF THE INVENTION

[0013] A recovery device according to one embodiment of the present invention and a processing system including the recovery device will be described with reference to Figures 1 and 2. Figure 1 is a diagram showing an overview of a recovery device 10 according to one embodiment of the present invention, and Figure 2 is a diagram explaining an overview of a processing system 100 including the recovery device 10 according to one embodiment of the present invention.

[0014] The recovery device 10 shown in Fig. 1 is used together with an aeration tank 110 and a settling tank 120 in a treatment system 100 shown in Fig. 2. The recovery device 10 is a device for recovering a recovered material from a liquid to be treated that contains activated sludge extracted from an aeration tank 110 that treats sludge-containing water discharged from a livestock facility or the like, and that contains sediment remaining after the supernatant is removed in the settling tank 120. In this embodiment, a mode will be described in which a biofilm or granules containing useful microorganisms such as anammox bacteria contained in sediment from activated sludge-containing water extracted from the aeration tank 110 is recovered as a recovered material, but the present invention is not limited thereto.

[0015] As an example, the scope of the present invention also includes an embodiment in which a flocculating agent is administered to wastewater containing sludge before it is fed into the aeration tank 110, thereby flocculating sludge flocs and collecting them as the collected material. In this way, when the recovery device 10 is used to recover flocs, the wastewater remaining after the flocs have been recovered can be administered to the aeration tank 110 for treatment, thereby reducing the treatment load on the aeration tank 110.

[0016] As shown in Figure 2, a treatment system 100 for treating wastewater discharged from livestock facilities or the like includes an aeration tank 110 that supplies oxygen to wastewater to be treated, which contains wastewater and microorganisms that decompose the nitrogen components in the wastewater, and a recovery device 10 that recovers recovered material in the water to be treated, including a portion of the sediment in the wastewater, that is withdrawn from the aeration tank 110. The treatment system 100 also includes a settling tank 120 that withdraws and stores a portion of the wastewater to be treated in the aeration tank.

[0017] In the treatment system 100, wastewater to be treated is first introduced into the aeration tank 110, and oxygen is supplied from a blower 111 via an aeration pipe 112. Then, nitrogen components in the wastewater are removed as gas by microorganisms introduced into the aeration tank 110 along with the wastewater. As wastewater treatment continues, sludge contained in the wastewater accumulates in the aeration tank 110 and may interfere with treatment, so the sludge must be periodically removed. The removed sludge contains microorganisms useful for wastewater treatment, so the microorganisms are recovered from the sludge. The mixture of sludge and wastewater removed from the aeration tank 110 is separated into a supernatant and a sediment in the settling tank 120. The supernatant is either released directly or used for further treatment. A portion of the sediment is returned to the aeration tank 110 as returned sludge. The remaining excess sludge is sent to the recovery device 10 for microorganism recovery.

[0018] In this embodiment, a configuration including the settling tank 120 is shown as an example, but the present invention is not limited to this, and the aeration tank 110 may function as the settling tank 120 by stopping aeration in the aeration tank 110. When the aeration tank 110 functions as the settling tank 120, the aeration in the aeration tank 110 is stopped, and the wastewater to be treated containing the settled excess sludge is extracted and sent to the recovery device 10.

[0019] The water to be treated containing excess sludge sent to the recovery device 10 is treated in a treatment tank 11. The recovery device 10 recovers biofilms in the water to be treated as a recovered material. The recovery device 10 includes the treatment tank 11, a recovery section 13, a liquid to be treated inlet section 12, a treated liquid outlet section 14, and a siphon pipe 15.

[0020] The treatment tank 11 accommodates the water to be treated and treats the water to separate the biofilm in the water from the water. The size of the treatment tank 11 can be set appropriately depending on the required treatment capacity, etc.

[0021] The collection unit 13 is provided to divide the treatment tank 11 into upper and lower sections. The collection unit 13 may be fixed to the inner wall of the treatment tank 11, or may be provided so that its vertical position and angle relative to the vertical are variable in response to changes in the water level in the treatment tank 11. If the position of the collection unit 13 is variable in response to changes in the water level in the treatment tank 11, a float may be attached to the collection unit 13 to allow it to float appropriately. If the angle of the collection unit 13 relative to the vertical is variable in response to changes in the water level in the treatment tank 11, one side of the collection unit 13 may be fixed to the treatment tank 11, and a float may be attached to the other side of the collection unit 13 to allow it to move appropriately. The installation position of the collection unit 13 is not particularly limited, but is preferably provided between the bottom and top surfaces of the treatment tank 11, above the treated liquid inlet 12 and below the treated liquid outlet 14. As a result, biofilm in the water to be treated that flows in from the liquid to be treated inlet section 12 and passes through the collection section 13 is captured in the collection section 13, and the treated water from which the biofilm has been removed is discharged from the treated liquid discharge section 14. The number of collection sections 13 does not need to be one, and multiple collection sections with different materials and mesh sizes may be present in layers. In this case, it is preferable that the collection section 13 on the bottom side has a larger mesh size.

[0022] The collection section 13 is preferably made of a metal such as stainless steel to reduce the frequency of replacement due to rust or deterioration, and the collection section 13 may be slit-shaped or mesh-shaped. This allows the liquid in the water to pass through the slits or mesh, and the biofilm, which is the collected material, is captured on the net. Since the collection section 13 is slit-shaped or mesh-shaped, fine debris and small clumps of microorganisms pass through the collection section 13, preventing frequent clogging of the collection section 13 and improving operating efficiency. In addition, the collection section 13 can be easily cleaned.

[0023] Furthermore, it is preferable that the collection section 13 has an opening width of 1 mm or more. This allows biofilms with a diameter of 1 mm or more to be collected, while other fine debris and small clumps of microorganisms pass through the collection section 13. This prevents frequent clogging of the collection section 13, improving operational efficiency, and enabling efficient collection of biofilms containing many useful microorganisms.

[0024] The liquid to be treated inlet section 12 is provided below the recovery section 13 in the treatment tank 11, and allows the water to be treated to flow into the treatment tank 11. The liquid to be treated inlet section 12 is connected to the settling tank 120 of the treatment system 100, and allows a liquid containing sediment, including activated sludge, that has settled in the settling tank 120 to flow into the treatment tank 11 as the water to be treated. The liquid to be treated inlet section 12 includes an opening provided in the treatment tank 11, and the diameter of the opening is appropriately set depending on the inflow amount or inflow rate of the water to be treated that is to flow into the treatment tank 11. The liquid to be treated inlet section 12 may also be provided with a flow rate adjustment valve (not shown). This makes it possible to adjust the inflow amount or inflow rate of the water to be treated from the liquid to be treated inlet section 12. The inflow rate of the water to be treated from the liquid to be treated inlet section 12 will be described in detail below.

[0025] The treated liquid discharge section 14 is provided above the collection section 13 in the treatment tank 11 and discharges the treated water that has passed through the collection section 13. Because the treated liquid discharge section 14 is provided above the collection section 13, the treated water discharged from the treated liquid discharge section 14 has passed through the collection section 13, and biofilm has been removed. The treated liquid discharge section 14 discharges the treated water from which biofilm has been removed to the outside of the system. The treated liquid discharge section 14 includes an opening provided in the treatment tank 11, and the diameter of the opening is set appropriately depending on the discharge amount or discharge speed of the treated water discharged from the treatment tank 11.

[0026] Siphon tube 15 is connected to treatment tank 11 below collection section 13, and uses a siphon mechanism to drain the liquid in treatment tank 11 when collection section 13 becomes clogged with a biofilm. Siphon tube 15 has a first end 16 connected to an opening provided in treatment tank 11 below collection section 13, and a second end 17 opposite first end 16.

[0027] The siphon pipe 15 is configured to discharge the liquid in the treatment tank 11 using a siphon mechanism. The siphon mechanism is a mechanism that generates a flow that discharges the water to be treated out of the treatment tank 11, opposite the flow that causes the water to flow into the treatment tank 11. The siphon mechanism is activated when the collection section 13 is clogged, and is used to remove the water to be treated that has accumulated in the treatment tank 11 from the opening to which the first end 16 is connected. The liquid discharged from the second end 17 of the siphon pipe 15 is returned to the aeration tank 110.

[0028] Siphon tube 15 has first tube 18 on the first end 16 side and second tube 19 on the second end 17 side connected in a U-shape or a C-shape. Siphon tube 15 is arranged so that the bottom of the U-shape or C-shape is on the upper side, and the up-down position of the bottom is vertically higher than treated liquid discharge portion 14. In addition, second end 17 of the siphon tube is located vertically lower than first end 16. This makes it easier for a reverse flow to occur due to the siphon mechanism, thereby improving the flow rate.

[0029] Furthermore, it is preferable that the diameter of second tube 19 on the second end side of siphon tube 15 is shorter than the diameter of first tube 18 on the first end side 16. In other words, second tube 19 is formed of a tube that is thinner than first tube 18. This makes it easier for the inside of second tube 19 to be filled with liquid, allowing the siphon mechanism to function smoothly.

[0030] Furthermore, it is preferable that the discharge rate of the liquid from siphon tube 15 is at least twice the inflow rate of the liquid to be treated from inlet portion 12. In this way, by using the siphon mechanism to make the discharge rate of the water to be treated from siphon tube 15 faster than the inflow rate of the water to be treated from inlet portion 12, the siphon mechanism can function smoothly.

[0031] With the above-described configuration, in the recovery device 10, when the water level of the water to be treated flowing from the liquid to be treated inlet 12 into the treatment tank 11 rises and passes the position of the recovery section 13, the water to be treated passes through the recovery section 13. At this time, the liquid components in the water to be treated pass through the recovery section 13, but the biofilm that cannot pass through the recovery section 13 adheres to the underside of the recovery section 13 and is captured. The water to be treated that has passed through the recovery section 13 and from which the biofilm has been removed is discharged from the treatment tank 11 through the treated liquid discharge section 14.

[0032] As treatment of the water to be treated by the recovery device 10 continues, the captured biofilm clogs the recovery section 13. This causes the water level in the siphon pipe 15 to rise, activating the siphon mechanism, resulting in backwash, which discharges the water to be treated out of the treatment tank 11. This causes the water level in the treatment tank 11 to drop, and the water to be treated passes from the top to the bottom of the recovery section 13. At this time, the biofilm attached to the recovery section 13 is recovered from the recovery section 13 by the water to be treated passing through the recovery section 13. The water to be treated containing the recovered biofilm is discharged from the siphon pipe 15 to the outside of the treatment tank 11 and returned to the aeration tank 110, where it is used for wastewater treatment. When the biofilm clogging the recovery section 13 is recovered and the blockage of the recovery section 13 is resolved, the water level in the siphon pipe 15 drops, the siphon mechanism stops, and the process of recovering the biofilm in the water to be treated that flows in from the water to be treated inlet section 12 resumes.

[0033] In this way, the collection device 10 operates the siphon mechanism depending on the blocked state of the collection section 13, allowing the collection device 10 to collect biofilms. In this way, the collection device 10 can collect biofilms with a simple structure. Furthermore, the collection device 10 automatically controls the operation and stop of the siphon mechanism depending on the blocked state of the collection section 13, eliminating the need for control using a timer or the like. Furthermore, the collection device 10 can collect biofilms of a desired size by changing the mesh width of the collection section 13 depending on the size of the biofilm to be collected.

[0034] (Variation 1) A recovery device 20, which is a first modified example of the recovery device 10, will be described with reference to Fig. 3. Fig. 3 is a diagram showing an overview of the first modified example of the recovery device 20 according to one embodiment of the present invention. As shown in Fig. 3, the recovery device 20 differs from the above-described recovery device 10 in that a recovery section 23 is provided so as to separate the treatment tank 21 into left and right sections. In the recovery device 20, the same components as those in the recovery device 10 are designated by the same component numbers, and details thereof will not be described.

[0035] In the recovery device 20, the treated liquid inlet 12 is provided in a treatment tank 21 partitioned into left and right parts by a recovery section 23, on the upstream side, i.e., on the right side in the drawing, of the recovery section 23. The treated liquid outlet 14 is provided downstream, i.e., on the left side in the drawing, of the recovery section 23. The siphon pipe 15 is connected upstream, i.e., on the right side in the drawing, of the recovery section 23.

[0036] As shown in variant example 1, the recovery device 20 functions in the same way as the recovery device 10 even when the treatment tank 21 is configured to be separated into left and right halves, and the siphon mechanism operates to recover biofilm depending on the blocked state of the recovery section 23.

[0037] (Variation 2) A recovery device 30, which is a second modified example of the recovery device 10, will be described with reference to Fig. 4. Fig. 4 is a diagram showing an overview of the second modified example of the recovery device according to one embodiment of the present invention. As shown in Fig. 4, the recovery device 30 differs from the above-described recovery device 10 in that it is provided with an automatic flushing mechanism for automatically flushing the recovery section 13. In the recovery device 30, the configuration other than the automatic flushing mechanism constituted by the water pipe 31 and the ball tap 32 is the same as that of the recovery device 10, and therefore the same component numbers are used and details thereof are omitted.

[0038] As shown in Figure 4, the recovery device 30 has an open top of the treatment tank 11, and a water pipe 31 is placed above it. A ball tap 32 is connected to the tip of the water pipe 31 by a chain, and is suspended from the water pipe 31 inside the treatment tank 11.

[0039] As shown in the left diagram in Figure 4, when the water level in treatment tank 11 is high and the water surface is above collection unit 13, ball tap 32 is pushed up, the chain bends, and water pipe 31 does not operate. On the other hand, as shown in the right diagram in Figure 4, when the water level in treatment tank 11 drops and the water surface is below collection unit 13, ball tap 32 drops down, the chain is pulled, water pipe 31 operates, water flows, and collection unit 13 is cleaned. Furthermore, when the water level in treatment tank 11 rises due to cleaning, ball tap 32 is pushed up, water from water pipe 31 stops, and cleaning ends.

[0040] In this way, in Modification 2, collection section 13 can be automatically cleaned in accordance with changes in the water level in treatment tank 11, thereby efficiently preventing clogging of collection section 13. Note that cleaning of collection section 13 is not limited to the embodiment of Modification 2, and may be performed by timer-controlling water pipe 31 to flow water at appropriate timing.

[0041] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Example]

[0042] [1. Consideration of biofilm size to be collected] We investigated the amount of anammox bacteria contained in biofilms and investigated the biofilm size suitable for recovery. We measured the amount of anammox bacteria contained in biofilms naturally growing in a swine wastewater treatment facility at the Shizuoka Prefectural Livestock Technology Research Institute's Small and Medium-sized Livestock Research Center by size. The amount of anammox bacteria was measured using real-time PCR using a primer set targeting the DNA of anammox bacteria. The results are shown in Figure 5.

[0043] As shown in Figure 5, the concentration of anammox bacteria increased with increasing biofilm size. When the biofilm size exceeded 1 mm, the concentration reached 1.0 × 10 11 The anammox bacteria are maintained at a concentration of 1000 copies / g or more, and high nitrogen removal capacity can be expected.

[0044] 2. Laboratory biofilm recovery test The recovery device shown in Figure 1 was constructed on a laboratory scale, and a biofilm recovery test was conducted. Biofilm (1-4 mm in size) containing anammox bacteria obtained from the Shizuoka Prefectural Livestock Technology Research Institute's Small and Medium-sized Livestock Research Center was mixed with activated sludge, and the resulting solution was introduced into a 1-L treatment tank through the inlet of the liquid to be treated at a flow rate of 525 mL / min. A filter with a mesh opening width of 1 mm was used as the recovery section. 21 g of biofilm was introduced into the treatment tank, and the amount of biofilm recovered from the siphon tube was measured.

[0045] The amount of biofilm collected by the collection device was 18 g, with a recovery rate of 86%.

[0046] [3. Biofilm recovery test at wastewater treatment facilities] The recovery device shown in Figure 1 was fabricated on a scale that would be used in an actual wastewater treatment facility, and a biofilm recovery test was conducted.3 ~50m 3 The capacity of the treatment tank of the recovery device was set to 45 to 60 L for the aeration tank. A steel wire screen with 1 mm slits was used as the recovery section. The treatment tank was set up so that the treated liquid, from which biofilm had been removed, was discharged outside the system from the treated liquid discharge section. In addition, the system was set up so that the biofilm-containing sludge discharged from the siphon pipe when the siphon mechanism was operating would return to the aeration tank.

[0047] The treated water containing activated sludge removed from the aeration tank was flowed into the treatment tank through the treated water inlet at a flow rate of 70 L / min. The weight of the biofilm in the treated water and the weight of the biofilm in the effluent discharged from the siphon tube were measured. The results are shown in Figure 6.

[0048] As shown in Figure 6, in all trials, the siphon discharge liquid contained a high concentration of biofilm, and the biofilm was successfully recovered. Furthermore, in all trials, the treated liquid discharged from the treated liquid discharge section to the outside of the system did not contain biofilm with a diameter of 1 mm or more. [Explanation of symbols]

[0049] 10 Recovery device 11 Treatment tank 12 Processed liquid inlet 13 Collection Department 14 Processing liquid discharge section 15 Siphon tube 16 First end 17 Second end 100 Processing Systems 110 Aeration tank 120 Sedimentation tank

Claims

1. A recovery device for recovering substances in a liquid to be treated, a treatment tank for treating the liquid to be treated; a collection section provided to separate the treatment tank into upper and lower or left and right sections, the collection section capturing the collected matter in the treatment liquid that has passed through the collection section; a liquid to be treated inlet section provided in the treatment tank below or upstream of the recovery section, for allowing the liquid to be treated to flow into the treatment tank; a treated liquid discharge section provided in the treatment tank above or downstream of the recovery section, for discharging the treated liquid that has passed through the recovery section; a siphon pipe connected to the treatment tank below or upstream of the recovery unit, for discharging the liquid in the treatment tank by a siphon mechanism when the recovery unit is clogged with the recovered material; A recovery device comprising:

2. The recovery device according to claim 1 , wherein the recovery section has a slit shape or a mesh shape.

3. The recovery device according to claim 2 , wherein the recovery section has an opening width of 1 mm or more.

4. The recovery device according to claim 1 , wherein the diameter of the siphon tube at a second end opposite to the first end connected to the treatment tank is smaller than the diameter of the first end.

5. The recovery device according to claim 4 , wherein the second end of the siphon tube is positioned vertically lower than the first end.

6. 4. The recovery device according to claim 1, wherein the discharge rate of the liquid from the siphon tube is at least twice as fast as the inflow rate of the liquid to be treated from the liquid to be treated inlet portion.

7. 1. A treatment system for treating wastewater, comprising: an aeration tank for supplying oxygen to the wastewater to be treated, the wastewater containing microorganisms capable of decomposing nitrogen components in the wastewater; The recovery device according to any one of claims 1 to 3, which recovers a recovered substance in the liquid to be treated that contains a part of the sediment in the wastewater to be treated that is extracted from the aeration tank; A processing system comprising:

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