Water treatment device

Abstract

To provide a water treatment device which allows for simple operation and has improved maintainability.SOLUTION: A water treatment device includes: a plurality of adsorbent-filled tanks for performing adsorption treatment to raw water using an adsorbent; raw water supply pipes for supplying raw water to each of the adsorbent-filled tanks; a first treated water transfer path for transferring treated water flowing out from each adsorbent-filled tank toward a downstream device; and a second treated water transfer path for transferring treated water flowing out from each adsorbent-filled tank toward an upstream device, in which each adsorbent-filled tank has a first treated water outlet portion that discharges treated water toward the first treated water transfer path, a second treated water outlet portion that discharges treated water toward the second treated water transfer path, and a raw water supply unit to which a raw water supply pipe is connected, and the raw water supplied from the raw water supply unit moves upward in the adsorbent-packed tank and comes into contact with the adsorbent.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a water treatment device. [Background technology]

[0002] Conventionally, water treatment devices have been known that remove dissolved substances from wastewater by contacting the wastewater with an adsorbent. These water treatment devices have an adsorption treatment tank equipped with an adsorbent, such as ion exchange resin, activated carbon, or zeolite, and are capable of removing dissolved substances from wastewater by adsorbing them with the adsorbent. The adsorbent's adsorption capacity decreases after adsorbing a certain amount of dissolved substances. Therefore, water treatment devices are operated by replacing the adsorbent as needed depending on the concentration of dissolved substances in the treated water (treated water) and the duration of use.

[0003] The water treatment device described above includes a multi-stage water treatment device equipped with multiple adsorption treatment tanks connected in series. In this case, raw water (such as untreated wastewater) is passed through multiple adsorption treatment tanks sequentially from the upstream side, and adsorption treatment is performed continuously toward the downstream side. In this case, the adsorbent in the upstream adsorption treatment tank to which the raw water is supplied has a high concentration of dissolved substances in the raw water, so it can adsorb a large amount of dissolved substances even if its adsorption performance has deteriorated. In contrast, the adsorbent in the downstream adsorption treatment tank needs to recover dissolved substances from raw water with a reduced concentration of dissolved substances, and therefore requires a high treatment capacity.

[0004] When the adsorbent in the downstream adsorption treatment tank deteriorates to a level that makes it unusable, it becomes necessary to replace the downstream adsorbent. One method for replacing the adsorbent is to replace the downstream adsorbent with a new one and reuse the old downstream adsorbent as the upstream adsorbent. For example, a water treatment device is known that employs a system (multi-stage adsorption system) in which the adsorption treatment tanks in use are switched in sequence and the adsorbent in some of the adsorption treatment tanks that have been put into a dormant state is replaced (e.g., Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-60241 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, conventional multi-stage adsorption water treatment systems require the replacement of adsorbents in the adsorption tank. Therefore, adsorbents with reduced adsorption capacity must be removed from the adsorption tank at regular intervals, and new adsorbents must be refilled. During these procedures, the adsorption tank must be idle for long periods of time, which reduces the efficiency of water treatment.

[0007] One of the objectives of one embodiment of the present invention is to provide a water treatment device that allows for simple operation and improved maintainability. [Means for solving the problem]

[0008] One embodiment of the present invention is a water treatment device comprising: a plurality of adsorbent tanks that perform an adsorption treatment on raw water using an adsorbent; a raw water supply pipe that supplies raw water to each adsorbent tank; a first treated water transfer path that transfers the treated water flowing out of each adsorbent tank toward a downstream equipment; and a second treated water transfer path that transfers the treated water flowing out of each adsorbent tank toward a upstream equipment, wherein each adsorbent tank has a first treated water outlet that outputs the treated water toward the first treated water transfer path, a second treated water outlet that outputs the treated water toward the second treated water transfer path, and a raw water supply unit to which the raw water supply pipe is connected, and the raw water supplied from the raw water supply unit moves upward in the adsorbent tank and comes into contact with the adsorbent.

[0009] In the water treatment device, the treated water transferred through the second treated water transfer path may be returned to the raw water.

[0010] In the water treatment device, the second treated water outlet may be configured to be openable and closable by a first control valve.

[0011] In the above-mentioned water treatment device, during operation, the first control valve in one of the multiple adsorbent tanks may be controlled to be in an open state, and the first control valves in the remaining adsorbent tanks may be controlled to be in a closed state.

[0012] The water treatment device may further include an adsorbent supply unit that supplies adsorbent to each adsorbent-filled tank. The adsorbent supply unit may include an adsorbent introduction mechanism having an introduction unit that holds the adsorbent and a second control valve that is disposed below the introduction unit.

[0013] In the adsorbent feeding mechanism, the feeding unit may be configured to be movable above each adsorbent tank. Further, the feeding unit may include a weight sensor that detects the weight of the adsorbent held therein.

[0014] The water treatment device may further include an adsorbent storage section that stores the adsorbent to be supplied to the input section.

[0015] The water treatment device may further include a discharge conveyor capable of draining the adsorbent discharged from below each adsorbent-filled tank. The discharge conveyor may be common to all of the adsorbent-filled tanks.

[0016] One embodiment of the present invention is a control method for a water treatment device including multiple adsorbent tanks that perform adsorption treatment of raw water using an adsorbent. The control method for the water treatment device sequentially operates each adsorbent tank filled with an adsorbent by supplying raw water to each adsorbent tank at a predetermined first interval, and after all adsorbent tanks are in operation, controls the treated water from the adsorbent tank that has been in operation the longest to be returned to the raw water. After each predetermined second interval, the adsorbent is discharged from the adsorbent tank that has been controlled to return the treated water to the raw water, and controls the treated water from the remaining adsorbent tank that has been in operation the longest to be returned to the raw water, repeating the steps of:

[0017] In the above-described method for controlling a water treatment device, treated water flowing out of each adsorbent treatment tank except for the adsorbent-filled tank controlled to return the treated water to raw water may be transferred to downstream equipment.

[0018] In the above-described method for controlling a water treatment device, the raw water supplied to the adsorbent-filled tank may come into contact with the adsorbent while moving upward inside the adsorbent-filled tank.

[0019] In the above-described method for controlling a water treatment device, each adsorbent tank may have a first treated water outlet port through which treated water flows, and a second treated water outlet port located below the first treated water outlet port through which treated water flows. In this case, the adsorbent tank controlled to return the treated water to raw water may be controlled to flow the treated water through the second treated water outlet port, and the remaining adsorbent tanks may be controlled to flow the treated water through the first treated water outlet port.

[0020] In the method for controlling a water treatment device, the second treated water outlet may be configured to be openable and closable by a control valve, and the adsorbent tank controlled to return the treated water to raw water may be controlled so that the control valve is open. [Brief explanation of the drawings]

[0021] [Figure 1]1 is a block diagram showing an overview of a water treatment system according to one embodiment of the present invention. [Figure 2] 1 is a block diagram showing an overview of a water treatment device according to an embodiment of the present invention. [Figure 3] 1 is a plan view schematically illustrating a configuration of a water treatment system according to an embodiment of the present invention. [Figure 4] 1 is a side view schematically showing the configuration of a water treatment system according to one embodiment of the present invention. [Figure 5] 1 is a front view schematically illustrating a configuration of a water treatment device according to an embodiment of the present invention. [Figure 6] FIG. 2 is a front view schematically showing a state in which an input unit has moved in the water treatment device according to the embodiment of the present invention. [Figure 7] FIG. 2 is a front view schematically showing a state in which the adsorbent is being discharged from the adsorbent-filled tank in the water treatment device according to the embodiment of the present invention. [Figure 8] FIG. 2 is a schematic diagram for explaining a control method of the water treatment device according to one embodiment of the present invention. [Figure 9] FIG. 2 is a schematic diagram for explaining a control method of the water treatment device according to one embodiment of the present invention. [Figure 10] 1 is a side view schematically showing the configuration of a water treatment system according to one embodiment of the present invention. [Figure 11] 1 is a front view schematically illustrating a configuration of a water treatment device according to an embodiment of the present invention. [Figure 12] 1 is a block diagram showing an overview of a water treatment system according to one embodiment of the present invention. [Figure 13] FIG. 2 is a schematic diagram for explaining the movement of water in the water treatment system according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be embodied in various forms without departing from the spirit of the present invention, and should not be construed as being limited to the description of the embodiments exemplified below. To clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part more schematically than the actual form, but these are merely examples and do not limit the interpretation of the present invention.

[0023] In this specification and each drawing, elements having the same function as those described in the previous drawings may be assigned the same reference numeral, and duplicate explanations may be omitted. Furthermore, when multiple elements having similar functions exist in one drawing, they may be distinguished from one another by assigning an alphabetical character after the same reference numeral. However, when there is no need to particularly distinguish between such multiple elements, the specification may describe the elements using only the reference numerals.

[0024] [First embodiment] [Water treatment system overview] FIG. 1 is a block diagram illustrating an outline of a water treatment system 10 according to one embodiment of the present invention. The water treatment system 10 of this embodiment includes a raw water storage tank 11, a raw water filtrate storage tank 12, a flow rate adjustment tank 13, a water treatment device 100, a treated water storage tank 14, and a treated water filtrate storage tank 15. However, the configuration of the water treatment system 10 is not limited to this example and may include at least the water treatment device 100. For example, the water treatment system 10 may omit any or all of the raw water storage tank 11, the raw water filtrate storage tank 12, the flow rate adjustment tank 13, the treated water storage tank 14, and the treated water filtrate storage tank 15, or may include other equipment. Although not illustrated in FIG. 1 , a pump may be provided in the piping as appropriate. For example, a pump may be provided in at least one of the piping between the raw water filtrate storage tank 12 and the flow rate adjustment tank 13 and the piping on the outlet side of the treated water filtrate storage tank 15. 1, the solid arrows indicate the basic movement of water, and the dotted arrows indicate the movement of water when treated water is returned (returned).

[0025] The raw water storage tank 11 is a tank that temporarily stores raw water (water to be treated) to be purified. The raw water is, for example, industrial wastewater or domestic wastewater. The raw water storage tank 11 stores raw water supplied via pipes from a factory or the like. The raw water filtrate storage tank 12 is a tank that filters the raw water to remove solids from the raw water. For example, a sand filtration device can be used as the raw water filtrate storage tank 12, but is not limited to this example. A pH adjustment tank that adjusts the pH of the raw water may be connected to the raw water storage tank 11 or the raw water filtrate storage tank 12.

[0026] The flow rate adjustment tank 13 is disposed between the raw water filtrate storage tank 12 and the water treatment device 100, and adjusts the flow rate of the raw water supplied to the water treatment device 100. Specifically, the flow rate adjustment tank 13 has the function of adjusting the flow rate of the raw water supplied to the water treatment device 100 to a constant value.

[0027] The water treatment device 100 is a device that performs a purification process (specifically, an adsorption process) on supplied raw water. Specifically, the water treatment device 100 of this embodiment has a function of removing dissolved substances (colloid particles and fine particles) from the raw water. The specific structure of the water treatment device 100 will be described later.

[0028] The treated water storage tank 14 is a tank that stores treated water (purified water after adsorption treatment) that has been purified by the water treatment device 100. The treated water filtrate storage tank 15 is a tank that filters the treated water to remove solids remaining in the treated water. As with the raw water filtrate storage tank 12, the treated water filtrate storage tank 15 can be, for example, a sand filter, but is not limited to this example. In addition, a pH adjustment tank that adjusts the pH of the treated water may be connected to the treated water storage tank 14 or the treated water filtrate storage tank 15. The treated water stored in the treated water filtrate storage tank 15 may be supplied to a facility located outside the water treatment system 10 via piping or the like, or may remain stored in the treated water filtrate storage tank 15.

[0029] [Water treatment equipment overview] Fig. 2 is a block diagram showing an overview of a water treatment device 100 according to one embodiment of the present invention. The water treatment device 100 of this embodiment includes an adsorbent supply unit 110, an adsorbent filling tank 120, an adsorbent discharge unit 130, and a control unit 140. In Fig. 2, solid arrows indicate the movement of water. Dot-dash arrows indicate the movement of adsorbent. Broken arrows indicate communication paths.

[0030] As shown in Fig. 2, raw water supplied to water treatment device 100 (specifically, raw water supplied from flow rate adjustment tank 13 shown in Fig. 1) is subjected to adsorption treatment in adsorbent filling tank 120 and transferred as treated water from water treatment device 100 (specifically, transferred to treated water storage tank 14 shown in Fig. 1). The adsorbent used in the adsorption treatment is temporarily stored in adsorbent supply unit 110 and supplied to adsorbent filling tank 120 at a predetermined timing. Thereafter, the adsorbent used in adsorbent filling tank 120 is discharged by adsorbent discharge unit 130 at a predetermined timing.

[0031] In this embodiment, an adsorbent using a carbide as a carrier is used as the adsorbent. Specifically, the water treatment device 100 brings raw water into contact with the adsorbent filled inside the adsorbent-filled tank 120, thereby adsorbing dissolved substances (e.g., organic substances) contained in the raw water into the pores of the carbide and removing them. For example, in this embodiment, a carbide supporting iron and / or magnesium on the surface or inside the pores is used as the adsorbent, thereby enabling efficient removal of phosphorus contained in the raw water. The removal of phosphorus using a carbide supporting iron or magnesium is described, for example, in JP 2019-107632 A. Note that, although this embodiment illustrates an example of using chemical adsorption using a carbide as a carrier, the present invention is not limited to this example. For example, physical adsorption using zeolite as a carrier can also be used.

[0032] The control unit 140 has a role of controlling each of the adsorbent supply unit 110, the adsorbent filling tank 120, and the adsorbent discharge unit 130. Specifically, the control unit 140 controls the timing of adsorbent supply by the adsorbent supply unit 110, and the timing of adsorbent discharge by the adsorbent discharge unit 130. The control unit 140 may control the adsorbent supply unit 110, the adsorbent filling tank 120, and / or the adsorbent discharge unit 130 based on detection signals output from various sensors provided in the adsorbent supply unit 110, the adsorbent filling tank 120, and / or the adsorbent discharge unit 130.

[0033] [Water treatment system configuration] FIG. 3 is a plan view schematically illustrating the configuration of a water treatment system 10 according to one embodiment of the present invention. FIG. 4 is a side view schematically illustrating the configuration of a water treatment system 10 according to one embodiment of the present invention. However, in FIGS. 3 and 4, the control unit 140 shown in FIG. 2 is omitted. FIGS. 3 and 4 are merely schematic diagrams, and some of the components may be omitted to simplify the drawings. The configuration of the water treatment system 10 is not limited to the configuration shown in FIGS. 3 and 4, and other components may be added, or some of the components shown may be omitted.

[0034] As shown in Fig. 3, water treatment system 10 of this embodiment is a water treatment structure in which a series of facilities from raw water storage tank 11 to filtered water storage tank 15 for treated water shown in Fig. 1 are integrated (unitized). Specifically, the system has a structure in which a series of facilities from raw water storage tank 11 to filtered water storage tank 15 for treated water are arranged on tank installation section 20. Tank installation section 20 is a structure that functions as the base of water treatment system 10.

[0035] In FIG. 3 , tanks other than the water treatment device 100 are arranged above the tank installation section 20: a raw water storage tank 11, a raw water filtrate storage tank 12, a flow rate adjustment tank 13, a treated water storage tank 14, a treated water filtrate storage tank 15, and a cleaning wastewater storage tank 17. All tanks except the flow rate adjustment tank 13 are arranged in a row on the tank installation section 20. The cleaning wastewater storage tank 17 temporarily stores cleaning wastewater containing a high concentration of solids when cleaning the raw water filtrate storage tank 12 and the treated water filtrate storage tank 15. However, the cleaning wastewater storage tank 17 is not an essential component, and the cleaning wastewater may be directly discharged to the outside. In this embodiment, a wastewater treatment unit 16 is arranged adjacent to the treated water filtrate storage tank 15. The wastewater treatment unit 16 is a unit for discharging excess treated water that cannot be stored inside the treated water filtrate storage tank 15 to the outside.

[0036] A plurality of pipes (not shown) are provided between each tank and the water treatment device 100 (or between each tank), and each tank and the water treatment device 100 are connected by the pipes. Pumps 18 are connected to each pipe as needed to assist in the transfer of raw water or treated water flowing through each pipe. For example, pump 18a is provided in the pipe connecting the raw water filtrate water storage tank 12 and the flow rate adjustment tank 13. Pump 18b is provided in the pipe connecting the raw water storage tank 11 and the treated water filtrate water storage tank 15 to the water treatment device 100. Pump 18c is provided in the pipe connecting the treated water storage tank 14 and the treated water filtrate water storage tank 15 to the water treatment device 100. Pumps 18d and 18e are provided to send wastewater from the wastewater treatment unit 16 and the cleaning wastewater storage tank 17, respectively. However, the arrangement and placement of each tank is not limited to the example shown in FIG. 3 .

[0037] 3 and 4, the water treatment device 100 includes an adsorbent supply unit 110, an adsorbent-filled tank 120, and an adsorbent discharge unit 130. In this embodiment, after the adsorbent is supplied from the adsorbent supply unit 110 to the adsorbent-filled tank 120, raw water is supplied from the raw water filtrate water storage tank 12 to the adsorbent-filled tank 120 for adsorption treatment. The raw water supplied from the raw water filtrate water storage tank 12 is first supplied to a flow rate adjustment tank 13, where its flow rate is adjusted. The raw water, whose flow rate has been adjusted by the flow rate adjustment tank 13, is distributed to each of the adsorbent-filled tanks 120a to 120g.

[0038] The treated water that has been subjected to adsorption treatment in each of the adsorbent-filled tanks 120a to 120g is collected in the treated water storage tank 14 and then transported to an external facility or the like via the treated water filtrate storage tank 15. The adsorbent filled in the adsorbent-filled tank 120 is periodically replaced. When replaced, the used adsorbent is discharged via the adsorbent discharge section 130. The discharged adsorbent is subjected to a predetermined regeneration treatment and then reused.

[0039] [Configuration of water treatment device] Next, the configuration of water treatment device 100 will be described with reference to Figure 5 in addition to Figures 3 and 4. Figure 5 is a front view schematically showing the configuration of water treatment device 100 according to one embodiment of the present invention.

[0040] (Configuration of the adsorbent supply unit) 5, the adsorbent supply unit 110 has a function of supplying adsorbents to the adsorbent filling tanks 120a to 120g. The adsorbent supply unit 110 includes an adsorbent hopper 112 and an adsorbent charging mechanism 114.

[0041] The adsorbent hopper 112 includes a hopper body 112a and a control valve 112b. The hopper body 112a is a cylindrical container made of stainless steel or other material, with an inverted pyramidal (or conical) lower portion. The hopper body 112a serves to temporarily hold the adsorbent before supply. The control valve 112b is disposed below the hopper body 112a and serves as an opening / closing mechanism for controlling the amount of adsorbent dropping from an opening (not shown) provided at the bottom of the hopper body 112a. In this embodiment, a rotary valve is used as the control valve 112b, but the present invention is not limited to this example. The opening and closing timing of the control valve 112b can be controlled by the control unit 140 (see FIG. 2).

[0042] The adsorbent charging mechanism 114 has the function of receiving a certain amount of adsorbent from the adsorbent hopper 112, and transporting and charging the adsorbent to each of the adsorbent filling tanks 120a to 120g. The adsorbent charging mechanism 114 includes a charging section 114a, a control valve 114b, and a rail 114c.

[0043] The feeder 114a is a container made of stainless steel or the like, and temporarily holds a certain amount of adsorbent that has dropped from the adsorbent hopper 112. The amount of adsorbent held in the feeder 114a can be controlled, for example, based on the detection value of a weight sensor (not shown) arranged in the feeder 114a. Specifically, the detection value of the weight sensor is monitored by the control unit 140 (see FIG. 2), and the control valve 112b of the adsorbent hopper 112 is closed when the amount of adsorbent supplied to the feeder 114a reaches a predetermined value. However, this is not limiting, and a method of detecting the amount of adsorbent supplied to the feeder 114a by placing a level sensor (not shown) above the feeder 114a and detecting the distance from the level sensor to the top surface of the adsorbent in the feeder 114a may also be used.

[0044] An opening (not shown) is provided below the loading section 114a, and a control valve 114b is disposed as an opening / closing mechanism for the opening. When the control valve 114b opens, the adsorbent held in the loading section 114a drops and is loaded into the adsorbent filling tank 120 located below. In this embodiment, a knife gate valve is used as the control valve 114b, but the present invention is not limited to this example. The opening and closing timing of the control valve 114b can be controlled by the control section 140 (see FIG. 2).

[0045] Although not shown, the adsorbent feeding mechanism 114 has a drive unit that allows the feeding unit 114a and the control valve 114b to move on the rails 114c. For example, the drive unit may include a power unit such as a motor and a sensor unit for determining the position of the feeding unit 114a. The water treatment device 100 of this embodiment is configured so that the feeding unit 114a and the control valve 114b move together on the rails 114c by controlling the drive unit with the control unit 140 (see FIG. 2). Specifically, as shown in FIG. 3, the rails 114c extend across all of the adsorbent filling tanks 120a to 120g, allowing the feeding unit 114a to move directly above each adsorbent filling tank 120.

[0046] 6 is a front view schematically illustrating a state in which input unit 114a has moved in water treatment device 100 according to one embodiment of the present invention. Specifically, the state is illustrated in which input unit 114a has moved to a position above adsorbent filling tank 120d, the fourth from the left. Here, the case in which adsorbent is filled into adsorbent filling tank 120d will be described as an example, but the same applies when adsorbent is filled into other adsorbent filling tanks 120.

[0047] In this embodiment, as described above, the adsorbent feeding mechanism 114 can individually feed filler to each of the adsorbent filling tanks 120a to 120g. For example, when feeding filler to the adsorbent filling tank 120d, a predetermined amount of adsorbent is first fed from the adsorbent hopper 112 to the feeding unit 114a. At this time, the amount of adsorbent fed to the feeding unit 114a may be measured by a weight sensor or the like provided in the feeding unit 114a.

[0048] After the adsorbent has been supplied to the supply unit 114a, as shown in FIG. 6, the supply unit 114a (and control valve 114b) is moved to above the adsorbent filling tank 120d by controlling a drive unit (not shown). After the supply unit 114a has been moved, the control valve 114b is then opened to supply the adsorbent held in the supply unit 114a into the adsorbent filling tank 120d. Thereafter, the supply unit 114a is moved to its original position (directly below the adsorbent supply hopper 112), and a predetermined amount of adsorbent is again supplied to the supply unit 114a. Thereafter, the above operation can be repeated multiple times until the predetermined amount of adsorbent is filled inside the adsorbent filling tank 120d.

[0049] (Configuration of adsorbent filling tank) The adsorbent tank 120 is a treatment tank for purifying (adsorption-treated) the raw water to be treated using an adsorbent, and is filled with the adsorbent supplied from the adsorbent supply unit 110. The adsorbent tank 120 of this embodiment includes a tank main body 121, a raw water supply pipe 122, a raw water supply unit 123, a first treated water outlet 124, a second treated water outlet 125, a first treated water transfer path 126, a second treated water transfer path 127, and a control valve 128. While FIG. 5 shows only the adsorbent tank 120a as a representative example, the other adsorbent tanks 120b-120g have the same structure as the adsorbent tank 120a. However, the configuration of the adsorbent tank 120 shown in FIG. 5 is merely an example, and does not preclude the addition of other elements or the elimination of any of the aforementioned elements.

[0050] Tank main body 121 is a housing for bringing raw water into contact with the adsorbent held therein, and is made of a material such as stainless steel. Raw water to be treated is supplied from a raw water supply unit 123 connected to a raw water supply pipe 122. Raw water supply unit 123 is provided below tank main body 121. Raw water supply pipe 122 is connected to flow rate adjustment tank 13 and transfers raw water whose flow rate has been adjusted. As shown in FIG. 5, raw water supply pipe 122 is connected to the raw water supply units 123 of each of adsorbent-filled tanks 120a-120g via control valves 122a, and supplies raw water to each of adsorbent-filled tanks 120a-120g. The control valves 122a may be, for example, stop valves such as ball valves, but are not limited to this example.

[0051] In this embodiment, raw water supply unit 123 includes an opening provided in tank main body 121. A mesh member (not shown) is provided in the opening to prevent the adsorbent filled inside tank main body 121 from falling out. That is, the inside of tank main body 121 and raw water supply pipe 122 are in communication with each other via the mesh member provided in raw water supply unit 123.

[0052] The first treated water outlet 124 and the second treated water outlet 125 are each provided above the tank main body 121. Specifically, the second treated water outlet 125 is located below the first treated water outlet 124. Both the first treated water outlet 124 and the second treated water outlet 125 include openings provided in the tank main body 121, and similar to the raw water supply unit 123, a mesh member (not shown) is provided to close the opening. The raw water supplied from the raw water supply unit 123 moves upward inside the tank main body 121 and comes into contact with the adsorbent. In other words, the supplied raw water undergoes adsorption treatment as it moves upward in the tank main body 121.

[0053] The first treated water outlet 124 includes an opening that is open to the outside, and the treated water that reaches the first treated water outlet 124 overflows and flows out of the tank main body 121 from the first treated water outlet 124. The treated water that flows out of the first treated water outlet 124 is transferred to a downstream facility via the first treated water transfer path 126. The downstream facility is a facility related to a process that follows the water treatment device 100 in the water treatment process. Specifically, the downstream facility is a facility that treats treated water that has completed the adsorption process by the water treatment device 100, and corresponds to, for example, the treated water storage tank 14. However, this example is not limiting. If another treatment tank exists between the water treatment device 100 and the treated water storage tank 14, the other treatment tank corresponds to the downstream facility. If the treated water is directly supplied to the treated water filtrate storage tank 15, the treated water filtrate storage tank 15 corresponds to the downstream facility.

[0054] The first treated water transfer path 126 is provided in common to each of the adsorbent-filled tanks 120a-120g, and transfers all treated water flowing out from the first treated water outlets 124 of the adsorbent-filled tanks 120a-120g to downstream equipment. As shown in Figures 4 and 5, the first treated water transfer path 126 is arranged alongside the second treated water transfer path 127 (described below), and extends along the direction in which the adsorbent-filled tanks 120 are lined up. In this embodiment, the first treated water transfer path 126 is a roughly U-shaped member like a trough, and the treated water flowing out from each of the adsorbent-filled tanks 120a-120g joins together in the first treated water transfer path 126 and is transferred to downstream equipment.

[0055] The second treated water outlet 125 includes an opening that can be opened and closed by a control valve 125a. When the control valve 125a is open, the treated water that reaches the second treated water outlet 125 overflows and flows out of the tank main body 121 from the second treated water outlet 125. As described above, the second treated water outlet 125 is located lower than the first treated water outlet 124. Therefore, when the control valve 125a is open, the treated water preferentially flows out of the second treated water outlet 125. Therefore, by appropriately adjusting the flow rate of the raw water in the tank main body 121, the treated water can be extracted from the second treated water outlet 125 without flowing out of the first treated water outlet 124. Conversely, when the control valve 125a is in a closed state, the treated water that reaches the second treated water outlet 125 moves upward beyond the second treated water outlet 125 without overflowing, and flows out from the first treated water outlet 124 toward the outside of the tank main body 121.

[0056] The treated water flowing out from the second treated water outlet 125 is transferred toward the upstream equipment via the second treated water transfer path 127. The upstream equipment is equipment related to the treatment prior to the water treatment device 100 in the water treatment process. Specifically, it is equipment that treats the raw water supplied to the water treatment device 100, such as the raw water storage tank 11. In other words, the treated water returned to the upstream equipment via the second treated water transfer path 127 is returned to the raw water again. However, this is not limited to this example. If another treatment tank exists between the water treatment device 100 and the raw water storage tank 11, the other treatment tank corresponds to the upstream equipment. If the treated water is directly supplied to the raw water filtrate storage tank 12, the raw water filtrate storage tank 12 corresponds to the upstream equipment. Furthermore, instead of returning the treated water to the raw water storage tank 11 or the raw water filtrate storage tank 12, the treated water may be returned directly to the raw water supply pipe 122.

[0057] The second treated water transfer path 127, like the first treated water transfer path 126, is provided in common to each of the adsorbent-filled tanks 120a to 120g. That is, as shown in FIGS. 4 and 5, the second treated water transfer path 127 is arranged alongside the first treated water transfer path 126 and extends along the direction in which the adsorbent-filled tanks 120 are lined up. In this embodiment, the second treated water transfer path 127, like the first treated water transfer path 126, is formed of a roughly U-shaped member such as a trough. Note that in this embodiment, for convenience of explanation, the first treated water transfer path 126 and the second treated water transfer path 127 are set to different heights, but this is not limiting, and the first treated water transfer path 126 and the second treated water transfer path 127 may be set to the same height.

[0058] An opening (not shown) is provided at the bottom of the tank main body 121, and a control valve 128 is connected to this opening. The control valve 128 is a valve for controlling the timing of adsorbent discharge and can also be considered a discharge valve. The opening and closing operation of the control valve 128 is controlled by the control unit 140 shown in FIG. 2. The control valve 128 is preferably a valve with high water-stopping performance, and in this embodiment, a ball valve is used. When the control valve 128 is closed, it functions as a water-stopping means that blocks the opening, and when it is open, it functions as a means for discharging the adsorbent and raw water from the tank main body 121. In this embodiment, an example is shown in which a ball valve is used as the control valve 128, but this is not limited to this example. Other types of valves that perform a similar function, such as a butterfly valve, may also be used.

[0059] (Configuration of adsorbent discharge section) The adsorbent discharge section 130 is a device that transports the used adsorbent discharged from the adsorbent filling tank 120 toward an adsorbent recovery section (not shown). The adsorbent recovery section is a container for storing the discharged adsorbent, and may be, for example, a portable container such as a flexible container bag, or a stationary container.

[0060] As shown in Fig. 3, the adsorbent discharge section 130 includes a first discharge conveyor 130a and a second discharge conveyor 130b. As shown in Fig. 5, the first discharge conveyor 130a is disposed below each of the adsorbent filling tanks 120a-120g and is common to all of the adsorbent filling tanks 120a-120g. The first discharge conveyor 130a has the function of draining water from the discharged adsorbent while transporting it. Specifically, in this embodiment, a mesh conveyor is used as the first discharge conveyor 130a.

[0061] 7 is a front view schematically illustrating a state in which the adsorbent is being discharged from the adsorbent-filled tank 120a in the water treatment device 100 according to one embodiment of the present invention. As shown in FIG. 7, when the control valve 128 is opened, the adsorbent and raw water inside the tank main body 121 fall and are discharged. At this time, it is desirable to open the control valve 128 while operating (rotating) the first discharge conveyor 130a. Because a large amount of adsorbent has been filled inside the tank main body 121, operating the first discharge conveyor 130a to discharge the adsorbent evenly prevents excessive accumulation of the adsorbent below the control valve 128 and also speeds up drying of the adsorbent.

[0062] Because the belt portion of the first discharge conveyor 130a is made of mesh, of the adsorbent and raw water discharged from the adsorbent filling tank 120, the raw water passes through the mesh and is removed, leaving only the adsorbent on the belt. In this way, the first discharge conveyor 130a can drain the water while transporting the adsorbent, which has the advantage of accelerating the drying of the transported adsorbent. Note that, although the present embodiment shows an example in which a mesh conveyor is used as the first discharge conveyor 130a, the present invention is not limited to this example, and other types of conveyors that perform similar functions may be used.

[0063] Although not shown, the first discharge conveyor 130a is equipped with a cleaning device for cleaning the mesh-like belt portion. The cleaning device can spray water or the like from multiple cleaning nozzles arranged toward the belt portion, and by spraying water or the like onto the belt portion while operating the first discharge conveyor 130a, the belt portion can be cleaned (removal of adhering adsorbent, etc.). However, this is not a limitation, and the cleaning device can also be omitted.

[0064] The second discharge conveyor 130b is disposed adjacent to the downstream end of the first discharge conveyor 130a and serves to further transport the adsorbent transported by the first discharge conveyor 130a to the adsorbent recovery section (not shown). As described above, in this embodiment, a mesh conveyor is used as the first discharge conveyor 130a, allowing the adsorbent to be dried while being transported. Therefore, a regular belt conveyor with a belt portion made of an elastic material such as rubber can be used as the second discharge conveyor 130b. In this embodiment, the adsorbent discharged from the tank main body 121 is dried by the first discharge conveyor 130a before being transported to the adsorbent recovery section, thereby preventing problems such as the accumulation of moist adsorbent in the adsorbent recovery section and making it heavy.

[0065] As described above, the water treatment device 100 of this embodiment has the function of supplying adsorbent to each adsorbent-filled tank 120 and the function of discharging adsorbent from the adsorbent-filled tank 120, and is easy to operate and has better maintainability than conventional devices.

[0066] Furthermore, in each adsorbent-filled tank 120, the supplied raw water moves upward inside the adsorbent-filled tank 120 and comes into contact with the adsorbents. Typically, the adsorption performance of an adsorbent decreases as the adsorption amount increases. Therefore, the lower the adsorbents packed inside the adsorbent-filled tank 120, the faster their adsorption performance decreases because they are exposed to raw water with a higher concentration of dissolved substances. However, raw water with a high concentration of dissolved substances can be adsorbed to a certain extent even by adsorbents with reduced adsorption performance, so even lower adsorbents can achieve a certain level of adsorption effect. In this embodiment, the supplied raw water moves upward while contacting the adsorbents, and therefore comes into contact with adsorbents that maintain their adsorption performance as it moves upward. Therefore, raw water whose dissolved substance concentration has been reduced by the adsorption process comes into contact with adsorbents that maintain their adsorption performance as it moves upward, enabling efficient removal (adsorption) of dissolved substances from the raw water throughout the adsorbent-filled tank 120.

[0067] Furthermore, as will be described below, water treatment device 100 of this embodiment includes multiple adsorbent-filled tanks 120a-120g, and the adsorbent in each adsorbent-filled tank 120 is replaced cyclically at predetermined intervals. This eliminates the need to periodically stop operation of water treatment device 100 to replace the adsorbents in all adsorbent-filled tanks 120 at once, making it possible to suppress fluctuations in adsorption performance (e.g., phosphorus removal rate, etc.), and reducing loss of adsorbent treatment capacity for water treatment device 100 as a whole.

[0068] [Water treatment device operation] Next, a control method for water treatment device 100 will be described with reference to Figures 8 and 9. In Figures 8 and 9, the description focuses on the operation of adsorbent filling tank 120, and therefore elements other than those necessary for the description are omitted. The description will be given with reference to the configuration of water treatment device 100 shown in Figure 5 as necessary.

[0069] 8 and 9 are schematic diagrams illustrating a control method for water treatment device 100 according to one embodiment of the present invention. Figures 8 and 9 show the sequential changes in the operation of each of adsorbent tanks 120a-120g over time. The following description focuses on the flow of raw water and treated water into and out of each of adsorbent tanks 120a-120g.

[0070] 8 and 9 show the raw water supply unit 123, the first treated water outlet 124, and the second treated water outlet 125. In the following description, hatched areas indicate that no water is flowing in or out of the adsorbent-filled tank 120. Specifically, when the raw water supply unit 123 is hatched, it means that the control valve 122a is closed and no raw water is being supplied. Conversely, when the raw water supply unit 123 is not hatched, it means that the control valve 122a is open and raw water is being supplied. Similarly, when the second treated water outlet 125 is hatched, it means that the control valve 125a is closed and no treated water is being discharged. Conversely, when the second treated water outlet 125 is not hatched, it means that the control valve 125a is open and treated water is being discharged. In Figures 8 and 9, only the adsorbent-filled tank 120a is given the symbols indicating the raw water supply section 123, the first treated water outlet section 124, and the second treated water outlet section 125, but the other adsorbent-filled tanks 120b to 120g have the same configuration.

[0071] Furthermore, the arrows attached to raw water supply section 123, first treated water outlet section 124, and second treated water outlet section 125 indicate the flow direction of the raw water or treated water, respectively. In particular, the arrow attached to first treated water outlet section 124 indicates the direction of treated water flowing through first treated water transfer path 126, and the arrow attached to second treated water outlet section 125 indicates the direction of treated water flowing through second treated water transfer path 127.

[0072] In Figure 8, "DAY1" means the first day (first day) since the operation of the water treatment device 100 started. Although not shown in the figure, it is assumed that all of the adsorbent filling tanks 120a to 120g are filled with adsorbents in advance as of DAY1. The method of filling the adsorbents has already been explained using Figure 6. Furthermore, in all of the adsorbent filling tanks 120a to 120g, the control valves 128 (see Figure 5) are set to the closed state.

[0073] On DAY 1, raw water is first supplied to the raw water supply unit 123 of the adsorbent tank 120a located at the left end. In other words, only the control valve 122a (see FIG. 5) of the adsorbent tank 120a is open, and only the adsorbent tank 120a is in operation. Here, "in operation" means that the adsorbent tank 120 is filled with raw water, and adsorption treatment is performed on the raw water to produce treated water.

[0074] As shown in Figure 8, during DAY 1, only the adsorbent-filled tank 120a is in operation, and the control valve 125a (see Figure 5) provided in the second treated water outlet 125 is closed. Therefore, during DAY 1, the treated water flowing out from the first treated water outlet 124 of the adsorbent-filled tank 120a is transferred to downstream equipment via the first treated water transfer path 126. In this embodiment, the treated water transferred via the first treated water transfer path 126 is transferred to the treated water storage tank 14 (see Figure 3), but this is not limited to this example.

[0075] In this embodiment, after the operation of the water treatment device 100 is started, the control valve 122a is switched to the open state in order from the adsorbent filling tank 120a to the adsorbent filling tank 120g at predetermined intervals (one day in this embodiment). That is, the adsorbent filling tanks 120a to 120g are sequentially supplied with raw water one day at a time and set to an operating state.

[0076] "DAY 3" means that it is the third day since the start of operation of the water treatment device 100. That is, DAY 3 indicates that raw water was supplied to the adsorbent-filled tank 120b on the second day, and raw water was supplied to the adsorbent-filled tank 120c on the third day. At this time, the control valves 125a of the adsorbent-filled tanks 120a-120c are closed, and therefore the treated water from each of the adsorbent-filled tanks 120a-120c flows out from the first treated water outlet 124 and is transferred to downstream equipment via the first treated water transfer path 126.

[0077] "DAY 7" indicates that it is the seventh day since the start of operation of the water treatment device 100. On DAY 7, raw water has been sequentially supplied to the adsorbent tanks 120a-120g, and as a result, all of the adsorbent tanks 120a-120g are in operation. At this time, the control valves 125a of the adsorbent tanks 120a-120g are all closed, so the treated water from each of the adsorbent tanks 120a-120g flows out of the first treated water outlet 124 and is transferred to downstream equipment via the first treated water transfer path 126.

[0078] Next, "DAY 8" shown in FIG. 9 indicates the eighth day since the start of operation of the water treatment device 100. On DAY 8, in the adsorbent-filled tank 120a that has been in operation the longest (i.e., the tank to which raw water was first supplied), the control valve 125a (see FIG. 5) is controlled to switch to an open state, causing treated water to flow out from the second treated water outlet 125. The treated water flowing out from the second treated water outlet 125 is transferred to the upstream equipment via the second treated water transfer path 127 (see FIG. 5). In this embodiment, the treated water transferred via the second treated water transfer path 127 is transferred to the raw water filtrate storage tank 12 (see FIG. 1), but this is not limited to this example.

[0079] As described above, during DAY 8, the treated water from adsorbent tank 120a is returned to the raw water via second treated water transfer path 127, while the treated water from the remaining adsorbent tanks 120b-120g continues to be transferred to downstream equipment (treated water storage tank 14 shown in FIG. 3) via first treated water transfer path 126. Adsorbent tank 120a has already been in operation for seven days, and is considered to have the lowest adsorption performance (specifically, the removal rate of dissolved substances such as phosphorus) of the adsorbent among the adsorbent tanks 120a-120g. In other words, the treated water flowing out of adsorbent tank 120a may have a higher residual rate of dissolved substances such as phosphorus than the other adsorbent tanks 120b-120g, and it is therefore undesirable to mix it with the treated water flowing out of the other adsorbent tanks 120b-120g. Therefore, in this embodiment, the treated water from the adsorbent-filled tank 120a that has been in operation the longest is selectively controlled to be returned to raw water, and the treated water from the adsorbent-filled tank 120a, which is thought to have the lowest adsorption performance, is not used as the final treated water, thereby preventing a decline in the adsorption performance of the water treatment device 100 as a whole.

[0080] "DAY 9" means that it is the ninth day since the start of operation of the water treatment device 100. On DAY 9, the adsorbent filled in the adsorbent filling tank 120a is discharged and new adsorbent is supplied. That is, the adsorbent filling tank 120a, which was controlled to return the treated water to raw water on the previous day, DAY 8, undergoes adsorbent replacement work. The supply and discharge of the adsorbent are as described with reference to Figures 6 and 7, respectively. In this embodiment, the control valve 122a (see Figure 5) is closed in advance, and then the control valve 128 (see Figure 5) is switched to the open state to discharge the adsorbent.

[0081] Also, on DAY 9, in adsorbent tank 120b, which has been in operation the longest at this point, control valve 125a (see FIG. 5) is controlled to switch to the open state, causing treated water to flow out from second treated water outlet 125. The treated water flowing out from second treated water outlet 125 is transferred to the upstream equipment (raw water storage tank 11 shown in FIG. 3) via second treated water transfer path 127 (see FIG. 5). That is, during DAY 9, the treated water in adsorbent tank 120b is returned to raw water via second treated water transfer path 127, and the treated water in the remaining adsorbent tanks 120c to 120g continues to be transferred to downstream equipment (treated water storage tank 14 shown in FIG. 3) via first treated water transfer path 126. The reason for returning the treated water in adsorbent tank 120b to raw water is the same as that explained for adsorbent tank 120a on DAY 8.

[0082] "DAY 10" means that it is the 10th day since the start of operation of the water treatment device 100. On DAY 10, the adsorbent filled in the adsorbent-filled tank 120b is discharged, and new adsorbent is supplied. That is, the adsorbent in the adsorbent-filled tank 120b, which was controlled on the previous day, DAY 9, to return treated water to raw water, is replaced. On the other hand, the control valve 125a (see FIG. 5) of the adsorbent-filled tank 120c, which has been in operation the longest as of DAY 10, is switched to the open state, and the treated water is controlled to flow out from the second treated water outlet 125. As a result, the treated water in the adsorbent-filled tank 120c is returned to the raw water via the second treated water transfer path 127 (see FIG. 5).

[0083] On day 10, the adsorbent tank 120a is filled with new adsorbent and the control valve 122a is set to the open state, raw water is supplied, and the adsorption performance is restored and the adsorbent tank 120a is again in operation. Therefore, the control valve 125a (see FIG. 5) is again switched to the closed state, and the adsorbent tank 120a is controlled so that treated water flows out from the first treated water outlet 124.

[0084] Although not shown in the figures, operations similar to those described for DAYS 9 and 10 are repeated from DAY 11 onwards, and the adsorbent replacement work and the transfer destination of the treated water are cyclically carried out in each of the adsorbent tanks 120a-120g. That is, the water treatment device 100 of this embodiment repeatedly discharges the adsorbent from the adsorbent tank 120 that is controlled to return the treated water to the raw water every predetermined period of time (one day in this embodiment), and controls the treated water from the adsorbent tank 120 that has been in operation the longest out of the remaining adsorbent tanks 120 to return the treated water to the raw water.

[0085] As described above, the water treatment device 100 of this embodiment is capable of cyclically replacing the adsorbent in one adsorbent-filled tank 120 at predetermined intervals, while continuing the adsorption treatment continuously using the remaining adsorbent-filled tanks 120. Each operation in the adsorbent-filled tank 120, such as supplying raw water, removing treated water, and supplying and discharging adsorbent, can all be controlled by the control unit 140 (see FIG. 2). Therefore, this embodiment makes it possible to provide a water treatment device that allows for simple operation and has improved maintainability.

[0086] Furthermore, the water treatment device 100 of this embodiment selectively controls the adsorbent-filled tank 120 immediately before the adsorbent is replaced to return treated water to the raw water. In this way, treated water from an adsorbent-filled tank 120 with reduced adsorption performance is not added to the treated water of the water treatment device 100, thereby preventing a decrease in the adsorption performance of the water treatment device 100 as a whole. Furthermore, because the adsorption process itself is performed in each adsorbent-filled tank 120 until immediately before the adsorbent is replaced, the amount of dissolved substances (e.g., phosphorus) adsorbed by the adsorbent does not decrease compared to before. In other words, even when, for example, the discharged adsorbent is reused as fertilizer, a decrease in the quality of the fertilizer can be prevented. Furthermore, by returning treated water from the adsorbent-filled tank 120 immediately before the adsorbent is replaced to the raw water, the content of dissolved substances in the raw water can be reduced, and the removal rate of dissolved substances in each adsorbent-filled tank 120 can be improved.

[0087] (Variation) In the above embodiment, an example is shown in Fig. 8 in which, after the operation of water treatment device 100 is started, raw water is supplied sequentially from adsorbent filled tank 120a to adsorbent filled tank 120g, one day at a time, but the interval at which raw water is supplied is not limited to this example. For example, raw water may be supplied sequentially from adsorbent filled tank 120a to adsorbent filled tank 120g, with an interval of two or more days between each.

[0088] 9 shows an example in which the adsorbent tank 120 is cyclically switched between being controlled to return treated water to raw water and being controlled to replace the adsorbent every day, but the present invention is not limited to this example. For example, such switching may be performed every two days or more.

[0089] Furthermore, in this embodiment, the number of adsorbent filling tanks 120 is set to seven, and each of the above-mentioned operations, such as supplying raw water, replacing the adsorbent, and switching the destination of the treated water, is switched every day so that they are circulated over the course of a week. However, this is not limited to this example, and the number of adsorbent filling tanks 120 and the timing of switching each operation can be designed appropriately depending on the size of the plant, etc.

[0090] Second Embodiment In this embodiment, an example in which the configuration of the adsorbent-filled tank is different from that of the first embodiment will be described. In this embodiment, the differences from the first embodiment will be focused on. Therefore, the same elements as those in the water treatment system 10 of the first embodiment will be indicated in the drawings using the same reference numerals, and duplicated explanations may be omitted.

[0091] FIG. 10 is a side view schematically illustrating the configuration of a water treatment system 10A according to one embodiment of the present invention. FIG. 11 is a front view schematically illustrating the configuration of a water treatment device 100A according to one embodiment of the present invention. In the water treatment device 100A according to this embodiment, the positional relationship between the first treated water outlet 124A and the second treated water outlet 125A in the adsorbent-filled tank 120Aa is reversed from that in the first embodiment. Specifically, the first treated water outlet 124A is disposed below the second treated water outlet 125A. Furthermore, the first treated water outlet 124A and the second treated water outlet 125A both include openings provided in the tank main body 121, but in this embodiment, the opening of the first treated water outlet 124A is configured to be openable and closable by a control valve 124Aa.

[0092] Because the first treated water outlet 124A is located lower than the second treated water outlet 125A, when the control valve 124Aa is open, the treated water preferentially flows out of the first treated water outlet 124A. Therefore, by appropriately adjusting the flow rate of the raw water in the tank body 121, the treated water can be extracted from the first treated water outlet 124A without flowing out of the second treated water outlet 125A. Conversely, when the control valve 124Aa is closed, the treated water that reaches the first treated water outlet 124A moves upward beyond the first treated water outlet 124A without overflowing, and then flows out of the tank body 121 from the second treated water outlet 125A.

[0093] As in the first embodiment, the treated water flowing out from the first treated water outlet 124A is transported toward the downstream equipment via the first treated water transfer path 126A, and the treated water flowing out from the second treated water outlet 125A is transported toward the upstream equipment via the second treated water transfer path 127A.

[0094] Third Embodiment In this embodiment, a water treatment system 10B will be described that is based on the water treatment system 10A of the second embodiment and that adds a new configuration. As will be described later, the water treatment system 10B of this embodiment is configured to circulate water directly between the raw water filtrate storage tank 12 and the water treatment device 100. This embodiment will be described focusing on differences from the second embodiment. Therefore, the same elements as those in the water treatment system 10A of the second embodiment will be indicated in the drawings using the same reference numerals, and redundant explanations may be omitted.

[0095] In the second embodiment, as explained in the first embodiment using Figure 9, control (hereinafter referred to as "circulation control") is performed in which treated water is discharged from second treated water outlet 125A for adsorbent tank 120A, which has been in operation the longest, and the discharged treated water is transferred to upstream equipment (e.g., raw water filtrate storage tank 12).In other words, the water treatment system 10A of the second embodiment operates to prevent a decline in the adsorption performance of the water treatment device 100 as a whole by returning the treated water from adsorbent tank 120A, which is thought to have the lowest adsorption performance, to raw water rather than using it as final treated water.

[0096] The adsorbent filled in the adsorbent-filled tank 120A, for which the above-mentioned circulation control is being performed, has a dissolved substance (e.g., phosphorus) removal rate reduced to about 50%, and its performance as an adsorbent has been significantly reduced. Therefore, the adsorbent filled in the adsorbent-filled tank 120A, for which circulation control has been performed for a predetermined period, is subjected to an adsorbent replacement process.

[0097] Conventionally, attempts have been made to reuse adsorbents (i.e., adsorbents that have adsorbed phosphorus and the like) used in water treatment as fertilizer. In this case, it is desirable that the discharged adsorbent has adsorbed a sufficient amount of phosphorus and the like to serve as fertilizer. However, even if raw water is supplied to an adsorbent-filled tank 120A filled with an adsorbent with reduced adsorption performance at the same flow rate as other adsorbent-filled tanks 120A, it takes time for the amount of adsorbed phosphorus to increase to a level sufficient for use as fertilizer.

[0098] In view of the above circumstances, water treatment system 10B of the present embodiment is configured such that, when performing circulation control, raw water is supplied directly to adsorbent-filled tank 120A without passing through flow rate adjusting tank 13. Water treatment system 10B of the present embodiment will be described below.

[0099] FIG. 12 is a block diagram showing an overview of a water treatment system 10B according to one embodiment of the present invention. As in FIG. 1, solid arrows indicate basic water movement (the movement of water during water treatment), and dotted arrows indicate the movement of water during the return treatment of treated water under circulation control. As shown in FIG. 12, in the water treatment system 10B of this embodiment, only when the above-described circulation control is performed, water (specifically, raw water when supplied to the water treatment device 100A, and treated water when flowing out of the water treatment device 100A) circulates between the raw water filtrate storage tank 12 and the water treatment device 100A, as indicated by the dotted arrows. Note that the configuration of the water treatment system 10B is not limited to the example shown in FIG. 12, and the water may be configured to circulate between the raw water storage tank 11 and the water treatment device 100A.

[0100] Fig. 13 is a schematic diagram illustrating the movement of water in a water treatment system 10B according to one embodiment of the present invention. In Fig. 13, elements having the same reference numerals as those in Fig. 5 described in the first embodiment have the same functions as those described using Fig. 5, and therefore, redundant explanations may be omitted.

[0101] A major difference from the water treatment system 10 of the first embodiment is that there are two routes for supplying raw water to the raw water supply pipe 122. Specifically, as routes for supplying raw water, a route connecting the flow rate adjustment tank 13 and the adsorbent-filled tank 120 (hereinafter referred to as the "normal route") and a route connecting the raw water filtrate storage tank 12 and the adsorbent-filled tank 120 (hereinafter referred to as the "circulation route") are provided.

[0102] The normal route is the route through which raw water flows when adsorbent tank 120 is operating under normal control (control in which water treatment is performed). Normal control corresponds to the control executed on adsorbent tanks 120b to 120g on "DAY 8" in FIG. 9, for example. The circulation route is the route through which raw water flows when adsorbent tank 120 is operating under circulation control. Circulation control corresponds to the control executed on adsorbent tank 120a on "DAY 8" in FIG. 9, for example.

[0103] In the normal route, the flow rate adjustment tank 13 and the raw water supply pipe 122 are connected via a pipe 31. A control valve 32 is provided in the pipe 31, and the supply of raw water can be started or stopped by opening or closing the control valve 32. In the circulation route, the raw water filtrate storage tank 12 and the raw water supply pipe 122 are connected via a pipe 41. A control valve 42 is provided in the pipe 41, and the supply of raw water can be started or stopped by opening or closing the control valve 42. In addition, a pump 43 is provided between the raw water filtrate storage tank 12 and the pipe 41. In the circulation route, a large amount of raw water can be supplied from the raw water filtrate storage tank 12 to the adsorbent-filled tank 120 by the operation of the pump 43.

[0104] 13, when normal control is performed, control valve 32 is open and control valve 42 is closed. Also, control valve 124Aa of adsorbent tank 120 is open. Therefore, raw water supplied from the upstream equipment travels along the arrow indicated by the solid line while passing through flow rate adjustment tank 13, undergoes water treatment in adsorbent tank 120, and is then transferred to the downstream equipment as treated water.

[0105] 13, when circulation control is performed, control valve 32 is closed and control valve 42 is open. Also, control valve 124Aa of adsorbent tank 120 is closed. Therefore, water moves along the dotted arrows and circulates between raw water filtrate storage tank 12 and adsorbent tank 120. In other words, when circulation control is performed, raw water is supplied to adsorbent tank 120 directly from raw water filtrate storage tank 12 without passing through flow rate adjustment tank 13.

[0106] As described above, the water treatment system 10B of this embodiment is configured to supply raw water directly from the raw water filtrate storage tank 12 to the adsorbent-filled tank 120A filled with an adsorbent with deteriorated adsorption performance, and to return the treated water after water treatment to the raw water filtrate storage tank 12. In this case, when supplying raw water from the raw water filtrate storage tank 12 to the adsorbent-filled tank 120A, a large amount of raw water can be supplied using the pump 43. Therefore, by circulating a large amount of raw water between the raw water filtrate storage tank 12 and the adsorbent-filled tank 120A, the amount of adsorption of dissolved substances such as phosphorus can be efficiently increased even by an adsorbent with deteriorated adsorption performance.

[0107] The embodiments and their modifications of the present invention can be combined as appropriate as long as they are not mutually inconsistent. A water treatment device in which a person skilled in the art appropriately adds or deletes components or modifies the design, or adds or omits steps or modifies conditions, based on the water treatment device of the above-described embodiments or their modifications, is also included in the scope of the present invention as long as it includes the gist of the present invention.

[0108] Furthermore, even if there are other effects and advantages different from those brought about by the above-mentioned embodiments or their modified forms, if these are clear from the description in this specification or can be easily predicted by a person skilled in the art, they are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0109] 10...water treatment system, 11...raw water storage tank, 12...filtered water storage tank for raw water, 13...flow rate adjustment tank, 14...treated water storage tank, 15...filtered water storage tank for treated water, 16...wastewater treatment unit, 17...washed wastewater storage tank, 18, 18a to 18e...pump, 20...tank installation unit, 100...water treatment device, 110...adsorbent supply unit, 112...adsorbent hopper, 112a...hopper body, 112b...control valve, 114...adsorbent feeding mechanism, 114a...feeding unit, 114b...control Valve, 114c...rail, 120, 120a to 120g...adsorbent filled tank, 121...tank main body, 122...raw water supply pipe, 122a...control valve, 123...raw water supply section, 124...first treated water outflow section, 125...second treated water outflow section, 125a...control valve, 126...first treated water transfer path, 127...second treated water transfer path, 128...control valve, 130...adsorbent discharge section, 130a...first discharge conveyor, 130b...second discharge conveyor, 140...control section

Claims

1. a plurality of adsorbent-filled tanks for performing an adsorption treatment on raw water using an adsorbent; a raw water supply pipe for supplying raw water to each adsorbent filling tank; a first treated water transfer path for transferring the treated water flowing out of each adsorbent-filled tank toward a downstream facility; a second treated water transfer path for transferring the treated water flowing out of each adsorbent-filled tank toward the upstream equipment; Equipped with Each adsorbent-filled tank has a first treated water outlet portion that discharges treated water toward the first treated water transfer path, a second treated water outlet portion that discharges treated water toward the second treated water transfer path, and a raw water supply portion to which the raw water supply pipe is connected, The raw water supplied from the raw water supply unit moves upward in the adsorbent-filled tank and comes into contact with the adsorbent. Water treatment equipment.

2. The water treatment device according to claim 1 , wherein the treated water transferred through the second treated water transfer path is returned to a raw water storage tank, a raw water filtrate storage tank, or the raw water supply pipe.

3. The water treatment device according to claim 1 , wherein the second treated water outlet is configured to be openable and closable by a first control valve.

4. 4. The water treatment device according to claim 3, wherein during operation, the first control valve in one of the plurality of adsorbent tanks is controlled to be in an open state, and the first control valves in the remaining adsorbent tanks are controlled to be in a closed state.

5. an adsorbent supply unit that supplies an adsorbent to each adsorbent filling tank; The water treatment device according to claim 1 , wherein the adsorbent supply unit includes an adsorbent introduction mechanism having an introduction unit that holds the adsorbent and a second control valve that is disposed below the introduction unit.

6. The water treatment device according to claim 5 , wherein the input unit is configured to be movable above each of the adsorbent-filled tanks.

7. The water treatment device according to claim 5 , wherein the input unit includes a weight sensor that detects a weight of the adsorbent held therein.

8. The water treatment device according to claim 5 , further comprising an adsorbent storage section that stores the adsorbent to be supplied to the input section.

9. further comprising a discharge conveyor capable of draining the adsorbent discharged from below each adsorbent filling tank; The water treatment device according to claim 1 , wherein the discharge conveyor is common to each of the adsorbent-filled tanks.

10. A control method for a water treatment device having a plurality of adsorbent-filled tanks that perform adsorption treatment on raw water using adsorbents, supplying raw water to each of the adsorbent-filled tanks filled with an adsorbent in sequence at predetermined first intervals, thereby sequentially putting each of the adsorbent-filled tanks into an operating state; After all the adsorbent filled tanks are in operation, the treated water from the adsorbent filled tank that has been in operation the longest is controlled to be returned to the raw water; A control method for a water treatment device, which repeats the steps of discharging adsorbent from an adsorbent-filled tank that is controlled to return treated water to raw water every time a predetermined second period has elapsed, and controlling the treated water from an adsorbent-filled tank that has been in operation the longest among the remaining adsorbent-filled tanks to return to raw water.

11. The method for controlling a water treatment device according to claim 10, wherein treated water flowing out of each adsorbent treatment tank except for the adsorbent-filled tank controlled to return the treated water to raw water is transferred to a downstream facility.

12. The method for controlling a water treatment device according to claim 10 , wherein the raw water supplied to the adsorbent-filled tank moves upward inside the adsorbent-filled tank and comes into contact with the adsorbent.

13. Each adsorbent-filled tank has a first treated water outlet through which treated water flows out, and a second treated water outlet located below the first treated water outlet and through which treated water flows out, A control method for a water treatment device as described in claim 12, wherein an adsorbent-filled tank controlled to return the treated water to raw water is controlled to discharge the treated water from the second treated water outlet, and each of the remaining adsorbent-filled tanks is controlled to discharge the treated water from the first treated water outlet.

14. the second treated water outflow portion is configured to be openable and closable by a control valve, The method for controlling a water treatment device according to claim 13 , wherein the adsorbent tank controlled to return the treated water to raw water is controlled so that the control valve is in an open state.

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