Water treatment apparatus and water treatment method

Abstract

To provide water treatment equipment and a water treatment method which enable adjustment of chloride concentration.SOLUTION: Water treatment equipment comprises: a first filtration device which removes iron or manganese by causing water to flow through the same; a chemical solution injection device which injects chlorine to raw water supplied to the first filtration device, on a primary side of the first filtration device; a second filtration device which removes chlorine in first filtered water on a secondary side of the first filtration device; a first treatment water conduit through which first treatment water having undergone first filtration treatment flows from the first filtration device to the second filtration device; a second treatment water conduit through which second treatment water having undergone filtration treatment at a secondary side of the second filtration device flows; and a bypass flow passage which supplies first treatment water to the second treatment water conduit from the first treatment water conduit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a water treatment apparatus and a water treatment method.

Background Art

[0002] In a water treatment apparatus that filters raw water supplied from a water source such as a well, iron and manganese contained in well water are oxidized by sodium hypochlorite and removed by a filter medium filled in a filtration device. If the chlorine required for iron and manganese removal treatment is insufficient, normal treatment cannot be performed. Therefore, it is necessary to add chlorine so that a certain amount of chlorine is surplus on the secondary side of the filtration device. However, when the surplus chlorine concentration is high, it may interfere with direct use. Also, when the surplus chlorine concentration is low, normal treatment may not be performed because the chlorine concentration required for treatment becomes insufficient when the concentrations of iron and manganese in the raw water fluctuate. As a countermeasure, there is a method in which iron and manganese removal treated water containing a sufficient surplus chlorine concentration is passed through an activated carbon filtration device to remove chlorine, and then chlorine is added again on the secondary side to adjust to an appropriate chlorine concentration. However, installation of a plurality of chemical liquid injections is required, increasing the costs for equipment installation and maintenance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, an embodiment of the present invention aims to provide a water treatment apparatus and a water treatment method with a simple configuration that can adjust the chlorine concentration.

Means for Solving the Problems

[0005] The water treatment apparatus according to one embodiment of the present invention includes a first filtration device that removes iron or manganese contained in water by passing water therethrough, a chemical solution injection device that injects chlorine into raw water supplied to the first filtration device on the primary side of the first filtration device, a second filtration device that removes chlorine from the first treated water after filtration treatment on the secondary side of the first filtration device, a first treatment water passage through which the first treated water that has undergone the first filtration treatment flows from the first filtration device to the second filtration device, a second treatment water passage through which the second treated water that has undergone filtration treatment flows on the secondary side of the second filtration device, and a bypass passage that supplies the first treated water from the first treatment water passage to the second treatment water passage, and includes a water passage. The second filtration device includes a filtration tank, a suction pipe connected to the filtration tank, a recovery pipe connected to the filtration tank, and a flow path switching means for switching a plurality of processes including a filtration process and a backwashing process by switching the connection state of the plurality of flow paths. The flow path switching means includes a first flow path switching valve, a second flow path switching valve, and a bypass pipe having one end connected between the first flow path switching valve and the suction pipe and the other end connected between the recovery pipe and the second flow path switching valve to form the bypass flow path. The bypass pipe is provided with an on-off valve.

[0006] The water treatment apparatus according to another embodiment of the present invention includes a first filtration device that removes iron or manganese contained in water by passing water therethrough, a chemical solution injection device that injects chlorine into raw water supplied to the first filtration device on the primary side of the first filtration device, a second filtration device that removes chlorine from the first treated water after filtration treatment on the secondary side of the first filtration device, a first treatment water passage through which the first treated water that has undergone the first filtration treatment flows from the first filtration device to the second filtration device, a second treatment water passage through which the second treated water that has undergone the second filtration treatment flows on the secondary side of the second filtration device, and a bypass passage that supplies the first treated water from the first treatment water passage to the second treatment water passage, and includes a water passage The second filtration device includes a filtration tank, a suction pipe connected to the filtration tank, a recovery pipe connected to the filtration tank, and a flow path switching means for switching a plurality of processes including a filtration process and a backwashing process by switching the connection state of the plurality of flow paths. The flow path switching means includes a first flow path switching valve, a second flow path switching valve, and a bypass pipe having one end connected to the primary side flow path of the first flow path switching valve and the other end connected to the secondary side flow path of the second flow path switching valve to form the bypass flow path. The bypass pipe is provided with an on-off valve. The first flow path switching valve is connected to the first treatment water channel and the suction pipe. The second flow path switching valve connects the recovery pipe and the second treatment water channel 。

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a water treatment apparatus and a water treatment method that have a simple configuration and can adjust the chlorine concentration.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] Hereinafter, a water treatment device 1 and a water treatment method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 12. FIG. 1 is an explanatory diagram showing the configuration and flow of the water treatment device 1 according to the present embodiment. FIG. 2 is a side view of the second filtration device 14 of the water treatment device 1, and FIG. 3 shows a front view of the second filtration device 14. FIG. 4 is a side view showing a part of the configuration of the second filtration device 14. FIGS. 5 and 6 are explanatory diagrams showing the filtration process of the water treatment device, and FIGS. 7 and 8 are explanatory diagrams showing the backwashing process of the water treatment device. FIG. 9 is an explanatory diagram showing the flow of the filtration process and the backwashing process of the water treatment device.

[0010] As shown in FIG. 1, the water treatment device 1 includes a raw water pump 11 provided in a raw water supply source 10, a chemical injection device 12, a first filtration device 13, a second filtration device 14, a treatment water tank 15, a backwashing pump 16 connected to the treatment water tank 15, a treatment water channel 17, a backwashing water channel 18, a plurality of drainage channels 19, 20, and a control panel 30.

[0011] The water treatment device 1 injects a chemical solution into raw water from a supply source with a chemical solution injection device 12, and is configured to remove iron and manganese contained in the raw water by a first filtration device 13 and to remove solids such as sand present in the raw water. Further, the water treatment device 1 is configured such that the chlorine concentration of the first treated water from which iron and manganese have been removed by the first filtration device 13 can be adjusted by a second filtration device 14.

[0012] The treatment water passage 17 includes a plurality of water passages formed of piping members. The treatment water passage 17 includes a raw water passage 17a from the supply source 10 to the chemical solution injection device 12, a supply passage 17b from the chemical solution injection device 12 to the first filtration device 13, a passage 17c to a second three-way valve 42 on the primary side of the treatment flow path, a first treatment water passage 17d from the first filtration device 13 to the second filtration device 14, a passage 17e to a three-way valve 46 arranged on the secondary side of the treatment flow path, a second treatment water passage 17f from the second filtration device 14 to the treatment water tank 15, and a water supply passage connected to a water supply destination via the treatment water tank 15. Further, the treatment water passage 17 includes a test drain passage 19c branched from the first treatment water passage 17d and connected to the test drain D3, and a test drain passage 20c branched from the second treatment flow passage 17f and connected to the test drain D13. During the filtration treatment, water from the supply source 10 is sent to the water supply destination through the chemical solution injection device 12, the first filtration device 13, the second filtration device 14, and the treatment water tank 15 by the raw water pump 11.

[0013] The backwash water passage 18 includes a plurality of water passages formed of piping members. The backwash water passage 18 constitutes two systems of flow paths branched from the treatment water tank 15 and connected to the first filtration device 13 and the second filtration device 14, respectively. In the backwash treatment, water in the treatment water tank 15 is sent to the first filtration device 13 or the second filtration device 14 through the backwash water passage 18 by the backwash pump 16.

[0014] The first drain passage 19 includes a plurality of water passages formed of piping members. The first drain passage 19 includes a backwash drain passage 19a connected from the port P3 to the backwash drain D1, and a cleaning drain passage 19b connected from the port P9 to the cleaning drain D2.

[0015] The second drainage channel 20 includes a plurality of water channels formed by piping members. The first drainage channel 19 includes a backwash drainage channel 20a connected from port P13 to the backwash drain D11 and a cleaning drainage channel 20b connected from port P19 to the cleaning drain D12.

[0016] A check valve S1 and on-off valves S2 to S17 are provided at predetermined locations in each flow path. The check valve S1 regulates the flow in the flow path in one direction. The on-off valves S2 to S17 are, for example, electromagnetic on-off valves, and switch the connection state of the plurality of flow paths by opening and closing according to the control of the control unit 30a.

[0017] The supply source 10 is, for example, a well. A raw water pump 11 is provided in the supply source 10.

[0018] The raw water pump 11 includes a pump and a motor for driving the pump. The raw water pump 11 sends the water from the supply source 10 to the secondary side in the treatment water channel 17. Note that the raw water pump 11 may be, for example, a land pump or a submersible pump.

[0019] The chemical solution injection device 12 includes a chemical solution tank 21, an injection pump 22, and a flow rate detection device.

[0020] The chemical solution tank 21 stores a chemical solution containing an oxidizing agent, specifically sodium hypochlorite, inside. The injection pump 22 is, for example, a diaphragm pump driven by a solenoid. The injection pump 22 is connected to the chemical solution tank 21 and injects a predetermined amount of the chemical solution into the treatment water channel 17.

[0021] The first filtration device 13 includes a filtration tank 31, a suction pipe 32, a recovery pipe 33, and a flow path switching unit (flow path switching means) 34.

[0022] The filtration tank 31 is configured in a cylindrical shape having, for example, an upper wall, a lower wall, and a peripheral wall. The filtration tank 31 includes a filter medium section 31a inside and a gravel section 31b as a support layer disposed below the filter medium section 31a. The filter medium section 31a is configured by stacking a plurality of types of filter media. One of the plurality of filter media is configured to remove iron from the raw water into which the chemical solution has been injected. One of the plurality of filter media is configured to remove manganese from the raw water into which the chemical solution has been injected. One of the plurality of filter media is formed to be able to remove solids contained in the raw water.

[0023] The suction pipe 32 is connected to the filtration tank 31. One end of the suction pipe 32 is connected to the flow path switching unit 34, and the other end of the suction pipe 32 is disposed above the upper part of the filtration tank 31, for example, above the uppermost layer of the plurality of filter media.

[0024] The recovery pipe 33 is connected to the filtration tank 31, for example. One end of the recovery pipe 33 is connected to the flow path switching unit 34, and the other end is disposed below the lower part of the filtration tank 31, for example, below the lowermost layer of the plurality of filter media. The other end of the recovery pipe 33 is disposed at the position of the gravel section 31b, for example. That is, the recovery pipe 33 extends upward along the vertical direction from the lower end of the filtration tank 31, and the lower end of the pipe section is disposed near the bottom surface of the filtration tank 31. A recovery port 33a provided with a filter is provided at the lower end of the recovery pipe 33. The upper end of the pipe section is connected to the flow path switching unit 34, is configured to be connectable to a plurality of flow paths, and is configured such that the connection destination and the open / closed state can be switched.

[0025] The flow path switching unit 34 includes, for example, three three-way valves 41, 42, 43 and switches the connection states of a plurality of flow paths. The three-way valves 41, 42, 43 are solenoid valves, are connected to the control panel 30, and are configured such that the connection destination and the open / closed state can be switched. The three-way valves 41, 42, 43 each have three ports P1 to P3, P4 to P6, P7 to P9, and connect any two of these ports by switching the internal flow path by the control panel 30. For example, in the flow path switching unit 34, the three-way valve 43 may be omitted.

[0026] The flow path switching unit 34 switches the connection states of the primary-side treatment water channel 17b, the backwash water channel 18, the suction pipe 32, the recovery pipe 33, the secondary-side treatment water channels 17c and 17d, the backwash drain channel 19a, and the cleaning drain channel 19b by means of three three-way valves 41, 42, and 43.

[0027] The three-way valve 41 has three ports P1, P2, and P3 respectively connected to the supply-side treatment water channel 17b, the suction pipe 32, and the drain channel 19a on the drain side, and connects two of these flow paths by opening and closing the ports. The first three-way valve 41 connects, for example, the flow path 17b and the suction pipe 32, or connects the suction pipe 32 and the flow path 19a.

[0028] The three-way valve 42 has ports P4, P5, and P6 respectively connected to the backwash water channel 18, the recovery pipe 33, and the flow path 17c leading to the three-way valve 43 arranged on the secondary side of the treatment flow path, and connects two of these flow paths by opening and closing the ports. The second three-way valve 42 connects, for example, the recovery pipe 33 and the flow path 17c, or connects the flow path 18 and the recovery pipe 33.

[0029] The three-way valve 43 has three ports P7, P8, and P9 respectively connected to the flow path 17c leading to the second three-way valve 42 on the primary side of the treatment flow path, the secondary-side flow path 17d, and the flow path 19b on the test drain side, and connects two of these flow paths by opening and closing the ports. The three-way valve 43 connects, for example, the flow path 17c and the flow path 17d, or connects the flow path 17c and the flow path 19b.

[0030] The second filtration device 14 shown in FIGS. 1 to 9 includes a filtration tank 35, a suction pipe 36, a recovery pipe 37, and a flow path switching unit 38.

[0031] The filtration tank 35 has a filtration medium accommodated therein and is configured to allow water to pass through. The filtration tank 35 is configured, for example, in a cylindrical shape having an upper wall, a lower wall, and a peripheral wall. The filtration medium includes at least activated carbon and is configured to be able to remove chlorine from the first treated water. As an example, activated carbon 35a as a filtration medium and gravel 35b arranged below the activated carbon 35a are arranged in the filtration tank 35.

[0032] The suction pipe 36 is connected to the filtration tank 35. One end of the suction pipe 36 is connected to the flow path switching unit 38, and the other end of the suction pipe 36 is disposed above the uppermost layer of the plurality of filter media.

[0033] The recovery pipe 37 is connected to the filtration tank 35. One end of the recovery pipe 37 is connected to the flow path switching unit 38, and the other end is disposed below the lowermost layer of the plurality of filter media. That is, the recovery pipe 37 extends upward along the vertical direction from the lower end of the filtration tank 35, and the lower end of the pipe portion is disposed near the bottom surface of the filtration tank 35. A recovery port 37a provided with a filter is provided at the lower end portion of the recovery pipe 37. The upper end portion of the pipe portion is connected to the flow path switching unit 38, is configured to be connectable to a plurality of flow paths, and is configured such that the connection destination and the open / closed state can be switched.

[0034] The flow path switching unit 38 includes, for example, three three-way valves 44, 45, 46, a bypass pipe 47 constituting a bypass flow path 47a, a check valve 49 provided in the bypass pipe 47, and an on-off valve 48. The flow path switching unit 38 switches the connection states of a plurality of flow paths. The three-way valve 44 as the first flow path switching valve, the three-way valve 45 as the second flow path switching valve, and the three-way valve 46 as the third flow path switching valve are electromagnetic valves and are ball valves in which the flow path is switched by the rotation of an internal ball. The three-way valves 44, 45, 46 are connected to the control panel 30 and are configured such that the open / closed state can be switched. The three-way valves 44, 45, 46 each have three ports, and by switching the internal flow path by the control panel 30, any two of these ports are connected. For example, in the flow path switching unit 38, the three-way valve 46 may be omitted.

[0035] The first three-way valve 44 includes three ports P11, P12, P13 respectively connected to the supply-side treatment water channel 17d, the suction pipe 36, and the drainage-side drainage channel 20a, and connects any two of these flow paths by opening and closing the ports. The three-way valve 44 connects, for example, the flow path 17d and the suction pipe 36, or the suction pipe 36 and the flow path 20a.

[0036] The three-way valve 45 has ports P14, P15, and P16 that are respectively connected to the recovery pipe 37, the backwash water passage 18, and the passage 17e leading to the three-way valve 46 arranged on the secondary side of the treatment passage. By opening and closing the ports, two of these passages are connected. The three-way valve 45 connects, for example, the recovery pipe 37 and the passage 17e, or connects the passage 18 and the recovery pipe 37.

[0037] The three-way valve 46 has three ports P17, P18, and P19 that are respectively connected to the passage 17e leading to the three-way valve 45 on the primary side of the treatment passage, the secondary-side passage 17f, and the test drain-side passage 20b. By opening and closing the ports, two of these passages are connected. The three-way valve 46 connects, for example, the passage 17e and the passage 17f, or connects the passage 17e and the passage 20b.

[0038] The bypass pipe 47 constitutes a bypass passage that connects the first treatment water passage and the second treatment water passage in a communicable manner. One end of the bypass pipe 47 is connected, for example, between the port P12 of the three-way valve 44 and the suction pipe 36 of the flow path switching unit 38. The other end of the bypass pipe 47 is connected between the port P15 of the three-way valve 45 and the recovery pipe 37. Also, a ball valve 48 as an on-off valve and a check valve 49 are provided in the passage of the bypass pipe 47. As an example, the bypass pipe 47 includes a nylon tube 51, a plurality of tube couplings 52 that connect the nylon tube 51, a bushing 53, and a ball valve 54 with a check valve. The bypass pipe 47 serves as a concentration adjustment unit that injects a part of the first treatment water into the second treatment water through the bypass passage. That is, the bypass pipe 47 adjusts the chlorine concentration by adjusting the flow rate of the first treatment water passing through the bypass passage 47a.

[0039] As shown in FIGS. 10 to 14, the opening degree of the ball valve 48 can be adjusted under the control of the control unit 30a. That is, the bypass pipe 47, the ball valve 48, and the control unit 30a serve as a concentration adjustment unit that performs a concentration adjustment process for adjusting the mixing ratio of chlorine by adjusting the opening degree of the ball valve 48.

[0040] The second flow path switching unit 38 switches the connection states of the flow paths among the primary-side treatment water channel 17d, the backwash water channel 18, the suction pipe 36, the recovery pipe 37, the secondary-side second treatment water channel 17e, the backwash drain channel 20a, and the cleaning drain channel 20b by means of three three-way valves 44, 45, and 46.

[0041] Specifically, the fourth three-way valve 44 includes three ports P11, P12, and P13 connected to the supply-side first treatment water channel 17d, the suction pipe 36, and the drain-side drain channel 20a, and connects two of these flow paths by opening and closing the ports. The fifth three-way valve 45 has ports P14, P15, and P16 respectively connected to the backwash water channel 18, the recovery pipe 37, and the flow path 17e leading to the sixth three-way valve 46 arranged on the secondary side of the treatment flow path, and connects two of these flow paths by opening and closing the ports. The sixth three-way valve 46 has three ports P17, P18, and P19 respectively connected to the flow path 17e leading to the fifth three-way valve 45 on the primary side of the treatment flow path, the drain-side flow path 20b, and the secondary-side second treatment water channel 17f, and connects two of these flow paths by opening and closing the ports.

[0042] Also, the second flow path switching unit 38 injects a predetermined amount of the first treatment water into the second treatment water by flowing the first treatment water through the bypass flow path 47a by opening and closing the on-off valve 48 provided in the bypass pipe 47, thereby adjusting the chlorine concentration.

[0043] The treatment water tank 15 is a container configured to store the treatment water that has passed through the second filtration device 14. A liquid level sensor for detecting the liquid level position of the treatment water is provided in the treatment water tank 15. The liquid level sensor is connected to the control unit 30a via a signal line. The liquid level sensor detects the liquid level position of the treatment water and sends the liquid level information to the control unit 30a as an electrical signal.

[0044] The backwash pump 16 includes a motor and a pump unit having an impeller connected to the motor. The backwash pump pressurizes the water from the treatment water tank 15 and pumps it to the water supply destination on the secondary side.

[0045] The water supply pump 50 includes a motor and a single-stage or multi-stage pump section having an impeller connected to the motor. The water supply pump 50 pressurizes the water from the treatment water tank 15 and pumps it to the water supply destination on the secondary side.

[0046] The control panel 30 includes a storage unit that stores various data, a control unit 30a that controls the operations of each part based on a predetermined program, and an interface unit.

[0047] The storage unit stores various programs, various reference values, and threshold values, for example, as information necessary for control. Note that various threshold values and setting values are configured to be arbitrarily set and changed by the user, for example, by operation input.

[0048] For example, based on the detection values detected by each sensor, the control unit 30a performs various arithmetic processes, and controls the motor of the raw water pump 11 to perform variable speed operation or stop by controlling the frequency of the inverter. Specifically, the control unit 30a transmits a control signal to each inverter, and controls the inverter corresponding to the raw water pump 11 at a predetermined timing to control the operation of the pump.

[0049] Further, based on the detection values detected by sensors or operation inputs, for example, the control unit 30a performs various arithmetic processes, and controls the opening and closing of the plurality of valves 41 to 46 provided in the flow path switching units 34 and 38 as the flow path switching means and the valves S1 to S17 arranged in each flow path, thereby switching the connection state of the flow path.

[0050] The water treatment apparatus 1 performs a plurality of types of treatments by switching these flow paths and controlling the operations of the pumps 11 and 16. Specifically, the water treatment apparatus 1 performs a filtration treatment, a backwashing treatment, and a cleaning treatment under the control of the control unit 30a.

[0051] Further, based on the detection values detected by sensors or operation inputs, for example, the control unit 30a performs various arithmetic processes, and controls the opening and closing of the ports of the flow path switching units 34 and 38 and the valves S1 to S17, thereby switching the connection state of the flow path.

[0052] Note that the opening degree of the on-off valve 48 of the bypass pipe 47 is adjusted by the automatic control of the control unit 30a. FIGS. 10 to 14 are graphs showing the changes in the opening degree of the on-off valve 48 in the bypass pipe 47, the chlorine concentration, and the mixing ratio. FIG. 10 is a graph showing the relationship between the opening degree of the on-off valve 48 and the mixing ratio indicating the ratio of the raw water (first treated water) mixed with the treated water (second treated water). FIG. 11 is a table showing the relationship between the differential pressure before and after the bypass pipe and the mixing ratio when the target of the raw water chlorine concentration is 2 mg / L. FIG. 12 is a graph plotting the data of FIG. 11 for each opening degree of the on-off valve 48. FIG. 13 is a table showing the relationship between the differential pressure before and after the bypass pipe and the mixing ratio when the target of the raw water chlorine concentration is 5 mg / L, and FIG. 14 is a graph plotting the data of FIG. 13 for each opening degree of the on-off valve 48. As shown in FIG. 10, it can be seen that the opening degree of the on-off valve 48 is related to the mixing ratio. Therefore, by adjusting the opening degree of the on-off valve 48, it is possible to arbitrarily control how much raw water is mixed with the treated water.

[0053] Hereinafter, various operations performed by the water treatment apparatus 1 according to the present embodiment will be described with reference to FIGS. 1 to 9. FIGS. 5 and 6 show the filtration process, and FIGS. 7 and 8 show the backwashing process, respectively.

[0054] The filtration process is a function for performing a normal operation of removing impurities composed of iron, manganese, and solids from raw water by driving the chemical injection device 12 to inject a chemical into the raw water and performing filtration treatment in the filtration tank 31. In the filtration process, the control unit 30a drives the filtration devices 13 and 14 to inject a chemical into the raw water, removes impurities composed of iron, manganese, and solids from the raw water by performing filtration treatment in the filtration tank 31, and while removing chlorine in the filtration tank 35, adjusts to a predetermined chlorine concentration by means of a bypass pipe, which is a function for performing a normal operation.

[0055] The filtration process includes a chemical injection process of injecting chlorine into raw water on the primary side of the first filtration device, a first filtration process of removing iron or manganese contained in water by passing water through the first filtration device, a second filtration process of removing chlorine from the first treated water after filtration on the secondary side of the first filtration device, and a bypass process of adjusting the chlorine concentration by supplying the first treated water that has undergone the first filtration process between the first filtration device and the second filtration device to a second treatment water channel through which the second treated water that has undergone filtration on the secondary side of the second filtration device flows.

[0056] In the filtration process, the control unit 30a switches the three-way valves 41, 42, 43, 44, 45, 46 and the on-off valve S of the water passage so that the flow path from the primary side to the secondary side of the filtration devices 13 and 14 flows in the order of the treatment water channels 17a, 17b, the suction pipe 32, the filtration tank 31, the recovery pipe 33, the treatment water channels 17c, 17d, the suction pipe 36, the filtration tank 35, the recovery pipe 37, the treatment water channels 17e, 17f.

[0057] At this time, the bypass pipe 47 of the filtration device 14 is in an open state, and a predetermined amount of the first treated water among the first treated water is supplied to the second treated water.

[0058] That is, the control unit 30a opens the ports P1, P2, P5, P6, P7, P8 and closes the others in the first filtration device 13 to set the flow path for filtration treatment. Also, the control unit 30a opens the ports P11, P12, P15, P16, P17, P18 and the ball valve 54 with a check valve of the bypass pipe 47 and closes the others in the second filtration device 14 to set the flow path for filtration treatment.

[0059] In this state, the control unit 30a drives the raw water pump 11 at a predetermined timing. For example, based on the liquid level information detected by a liquid level sensor, when the control unit 30a detects that the liquid level in the treatment water tank 15 has dropped to a predetermined pump startup reference value, it drives the raw water pump 11. By driving the raw water pump 11, the raw water is pumped up and passes through the chemical injection device 12, the first filtration tank 31, and the second filtration tank 35, where filtration treatment and chlorine concentration adjustment are performed. That is, in the first filtration device 13, impurities such as iron, manganese, and solids are removed to obtain the first treated water L1. Further, by passing through the filtration tank 35 of the second filtration device 14, chlorine is removed, and a predetermined amount of the first treated water L1 is injected through the bypass flow path 47, resulting in the second treated water L2 with a predetermined chlorine concentration.

[0060] FIGS. 7 to 9 are explanatory diagrams showing the backwashing process. Here, a backwashing process using treated water is shown. The backwashing process is a process of backwashing the filter media by flowing backwash water from the recovery pipe 33, passing it through the filter media of the filtration tanks 31 and 35 from bottom to top, and draining it, and stirring the filter media inside the filtration tank 35 to maintain the removal ability. Note that there is no bypass flow path 47 in the filtration tank 31.

[0061] Specifically, the three-way valves 41, 42, 43, 44, 45, 46 and the on-off valve S of the water passage are switched so that the flow paths of the filtration devices 13 and 14 flow in the order of the backwash water passage 18, the recovery pipes 33, 37, the filtration tanks 31, 35, the suction pipes 32, 36, and the backwash drain passages 19a, 20a.

[0062] That is, in the first filtration device 13, the control unit 30a opens ports P4, P5, P2, P3, and valves S4, S5, S15, S16, and closes the others to set the flow path for backwashing. Also, in the second filtration device 14, the control unit 30a opens the flow paths of ports P14, P15, P12, P13 and valves S9, S10, S15, S16, and closes the others to set the flow path for the backwashing process.

[0063] In this state, when the control unit 30a drives the backwash pump 16 at a predetermined timing to send the backwash water L3 to the flow path switching units 34 and 38 respectively, it passes through the filter media from the recovery pipes 33 and 37, flows into the suction pipes 32 and 36, and is drained from the drain channels 19a and 20a. By this backwash treatment, the raw water flows from the bottom to the top of the filter tanks 31 and 35, thereby cleaning the filter media and discharging the oxides and fine particles accumulated in the filter tanks 31 and 35. At this time, since a check valve 49 is arranged in the bypass pipe 47, it is possible to prevent the raw water from flowing to the water supply destination during backwashing.

[0064] The cleaning treatment is a treatment for discarding the backwash water remaining inside the filter tanks 31 and 35 as drainage during the backwash treatment and cleaning the filter tanks. In the cleaning treatment, after passing through the filter tanks 31 and 35 through the same flow path as the filtration treatment, the treated water in the filter tank 31 is drained into the cleaning drain channel 19b without flowing into the treatment water channel 17d. The treated water in the filter tank 35 is drained into the cleaning drain channel 20b without flowing into 17f.

[0065] In the cleaning treatment, the control unit 30a sets the flow path so that the flow path from the primary side to the secondary side of the filtration device 13 flows in the order of the treatment water channels 17a, 17b, the suction pipe 32, the filter tank 31, the recovery pipe 33, the treatment water channel 17c, and the cleaning drain channel 19b. Also, the control unit 30a sets the flow path from the primary side to the secondary side of the filtration device 14 to flow in the order of the treatment water channels 17a, 17b, the suction pipe 32, the filter tank 31, the recovery pipe 33, the treatment water channels 17c, 17d, the suction pipe 36, the filter tank 35, the recovery pipe 37, the treatment water channel 17e, and the cleaning drain channel 20b.

[0066] The test drainage treatment is a treatment for collecting a part of the treated water, for example, for the purpose of checking the water quality. As the test drainage treatment, the control unit 30a can open the on-off valves S7 and S12 on the test drainage channels 19c and 20c from the open / closed state of the filtration treatment, collect the treated water from the test drainage channels 19c and 20c, and guide the treated water for maintenance to the test drains D3 and D13. At this time, the on-off valves S8 and S14 in the treatment water channels 17d and 17e may be closed or open. For example, when an abnormality is found in the water quality, S14 is closed so that water does not flow into the water tank 15, and the treated water is drained from D3 and D13 to perform maintenance.

[0067] According to the water treatment apparatus 1 and the water treatment method according to this embodiment, the following effects can be obtained. That is, a bypass pipe that communicates the secondary side of the first filtration tank and the secondary side of the second filtration tank is provided, and the first treated water after the first filtration treatment is injected into the second treated water after the second filtration treatment, so that the chlorine concentration can be adjusted with a simple device configuration. That is, for example, compared with the case where a chemical injection device is further provided on the secondary side of the second filtration device, the device configuration can be simplified, the equipment, the chemical cost on the secondary side, and the maintenance cost of the chemical injection device on the secondary side can be suppressed, and the installation space can be reduced. Further, by controlling the opening degree of the on-off valve of the bypass pipe 47, the chlorine concentration can be adjusted to a desired concentration. Further, since the amount of chlorine treated by the second filtration device decreases by the amount branched to the bypass pipe 47, the replacement cycle of the filter medium can be lengthened to reduce costs.

[0068] Furthermore, in the above embodiment, since the bypass pipe is connected between the flow path switching valve and the suction pipe and the recovery pipe, backwashing can be performed only by operating the flow path switching unit 38 to switch the flow path, and the raw water can be prevented from flowing out to the secondary side of the filtration device through the bypass pipe 47.

[0069] The present invention is not limited to the above-described embodiments as they are, and the specific configuration and processing of each part can be appropriately changed.

[0070] For example, in each of the above embodiments, an example of performing a backwashing process on the second filtration device 14 with treated water has been described. However, the present invention is not limited to this, and a backwashing process may be performed using the first treated water (raw water). For example, as another embodiment, the water treatment device 1A shown in FIGS. 15 to 20 includes a second filtration device 14A that performs a backwashing process using raw water. The second filtration device 14A includes a flow path 17g that branches from the treatment water path 17d and reaches the port P14 of the three-way valve 44. The first treated water that becomes raw water in the second filtration device 14A is supplied from the flow path 17g. In the second filtration device 14A, by opening the flow paths of the flow path 17g, ports P14, P15, P12, P13, and the valve S10 and closing the others, a flow path for the backwashing process with raw water can be set. That is, as shown in FIGS. 19 to 20, the first treated water that becomes raw water flows from the recovery pipe 37 into the activated carbon filtration tank 35 through the ports P14 and P15, passes through the upper 36a and 36, and is discharged from the backwashing drain D11 through the ports P12 and P13 of the three-way valve 44 and the on-off valve S10 to the backwashing drainage path 20a. As shown in FIGS. 15 to 18, the filtration process in the water treatment device 1A and the second filtration device 14A according to the present embodiment is performed in the same procedure as the water treatment device 1 and the second filtration device 14 described above.

[0071] In the above embodiment, an electric three-way valve switched by the control unit 30a is shown, but the present invention is not limited thereto, and the manual, automatic, shape, and structure can be appropriately changed. Further, in the above embodiment, an example in which the flow path switching unit 38 includes two three-way valves is shown, but a configuration using a five-way valve 140 integrally having the functions of the three-way valves 44 and 45 may be adopted. As another embodiment, the second filtration device 14B shown in FIGS. 21 to 25 includes a manual five-way valve 44A in the flow path switching unit 38. FIG. 21 is a front view showing the configuration of the second filtration device 14B, and FIGS. 22 and 23 are side views and plan views of the second filtration device 14B, respectively. FIG. 24 is an explanatory view showing the filtration process of the second filtration device 14B, and FIG. 25 is an explanatory view showing the backwashing process of the second filtration device 14B. In the second filtration device 14B, for example, the five-way valve 140, the bypass pipe 47, and the activated carbon filtration tank 35 are arranged in this order. When performing the filtration process, as shown in FIG. 26, a part of the first treated water flows into the second treated water. Further, as shown in FIG. 25, in the case of the backwashing process, since the check valve 49 is arranged in the bypass pipe 47, it is possible to prevent the raw water leakage in which the backwashing water flows backward through the bypass pipe 47 without closing the ball valve 48.

[0072] According to the present embodiment, it is not necessary to control an electric on-off valve, the object can be achieved at low cost, and it is possible to solve the problem with the same operation as the configuration without mounting a bypass pipe.

[0073] In the above-described first embodiment, an example was shown in which the bypass pipe 47 is arranged between the three-way valves 44 and 45, which are valves for reverse washing switching, and the filtration tank 35 in the flow path switching unit 38. However, the present invention is not limited to this. For example, as another embodiment, like the filtration device 14C of the water treatment device shown in FIG. 26 and the second filtration device 14D of the water treatment device shown in FIG. 27, the bypass pipe 47 may be arranged outside the flow path switching unit 38 including the three-way valves 44 and 45. In these embodiments, one end of the bypass pipe 47 is arranged on the primary side of, for example, the port P11 of the three-way valve 44 of the flow path switching unit 38, and the other end of the bypass pipe 47 is connected to the secondary side of the port P16 of the three-way valve 45. Further, a ball valve 55 as an on-off valve is provided in the flow path of the bypass pipe 47. As an example, the bypass pipe 47 includes a nylon tube 51, a plurality of tube couplings 52 connecting the nylon tubes 51, a bushing 53, and a ball valve 55. The opening degree of the ball valve 55 can be adjusted by the control unit 30a. The control unit 30a serves as a concentration adjustment means for adjusting the chlorine mixing ratio by adjusting the opening degree of the ball valve 55. In the present embodiment, by manually or automatically closing the ball valve 55 as a mixing ratio adjustment valve during reverse washing, it is possible to prevent raw water from leaking to the water supply destination during reverse washing. Also in the present embodiment, by injecting the first treated water L1 into the flow path of the second treated water L2 through the bypass pipe 47, it is possible to adjust the chlorine concentration with a simple configuration.

[0074] Further, as another embodiment, for example, as shown in FIG. 28, in order to make it easier for the user to manually adjust the opening degree, a scale 48a corresponding to the opening degree may be displayed on the on-off valve 48.

[0075] Furthermore, a concentration sensor for detecting the chlorine concentration may be provided on at least one or both of the primary side and the secondary side of the bypass flow path 47, and the opening degree of the on-off valve 48 of the bypass flow path 47 may be feedback-controlled based on the data of the chlorine concentration before or after the concentration adjustment, or both.

[0076] Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof at the implementation stage. Also, the respective embodiments may be implemented in appropriate combinations, and in that case, the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combinations selected from a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, if the problem can be solved and the effects can be obtained, the configuration from which these constituent elements are deleted can be extracted as an invention. The following is appended with a description equivalent to the invention described in the claims at the time of the original application of this application. (1) A first filtration device for removing iron or manganese contained in water by passing water, A chemical solution injection device for injecting chlorine into the raw water supplied to the first filtration device on the primary side of the first filtration device, A second filtration device for removing chlorine from the first treated water after the filtration treatment on the secondary side of the first filtration device, A water treatment device comprising a first treatment water channel through which the first treated water that has undergone the first filtration treatment flows from the first filtration device to the second filtration device, a second treatment water channel through which the second treated water that has undergone the second filtration treatment flows on the secondary side of the second filtration device, and a bypass flow path for supplying the first treated water from the first treatment water channel to the second treatment water channel. (2) The second filtration device has a filter medium containing activated carbon, The water treatment apparatus according to claim 1, further comprising a concentration adjustment unit configured to inject a predetermined amount of a part of the first treated water into the second treated water through the bypass channel. (3) The water treatment apparatus according to claim (2), wherein the concentration adjustment unit adjusts the chlorine concentration by adjusting the flow rate passing through the bypass channel. (4) The water treatment apparatus according to any one of (1) to (3), wherein the first filtration device and the second filtration device are provided with a flow path switching means for switching a plurality of processes including a filtration process and a backwashing process by switching a connection state of the plurality of flow paths. (5) The second filtration device includes a filtration tank containing a filtration material containing activated carbon, a suction pipe connected to an upper part of the filtration tank, and a recovery pipe connected to a lower part of the filtration tank. The flow path switching means is connected to the suction pipe, the recovery pipe, and a plurality of flow paths on the supply side and the discharge side, and includes a plurality of flow path switching valves for switching an open / closed state of the flow path. A bypass pipe having one end connected between the first flow path switching valve and the suction pipe and the other end connected between the recovery pipe and the second flow path switching valve to form the bypass channel is provided. The water treatment apparatus according to (4), wherein the bypass pipe includes an on-off valve and a check valve. (6) The second filtration device includes a filtration tank containing a filtration material containing activated carbon, a suction pipe connected to an upper part of the filtration tank, and a recovery pipe connected to a lower part of the filtration tank. The flow path switching means is connected to the suction pipe, the recovery pipe, and a plurality of flow paths on the supply side and the discharge side, and includes a plurality of flow path switching valves for switching an open / closed state of the flow path. A bypass pipe having one end connected to a primary side flow path of the first flow path switching valve and the other end connected to a secondary side flow path of the second flow path switching valve to form the bypass channel is provided. The water treatment apparatus according to (4), wherein the bypass pipe includes an on-off valve. (7) A first filtration process for removing iron or manganese contained in water by passing water through a first filtration device, a chemical solution injection process for injecting chlorine into raw water supplied to the first filtration device on the primary side of the first filtration device, a second filtration process for removing chlorine from the first treated water after the filtration process supplied to the second filtration device on the secondary side of the first filtration device, A bypass process for supplying the first treated water after the first filtration process from between the first filtration device and the second filtration device to a second treatment water channel through which the second treated water filtered on the secondary side of the second filtration device flows. (8) The second filtration device has a filtration material containing activated carbon, The water treatment method according to (7), comprising a concentration adjustment treatment of injecting a predetermined amount of the first treated water into the second treated water. (9) The water treatment method according to (8), wherein the concentration adjustment treatment adjusts the chlorine concentration by adjusting the flow rate through the bypass flow path. (10) The water treatment method according to any one of (7) to (9), wherein a plurality of processes including a filtration process and a backwashing process are switched by switching the connection state of a plurality of flow paths.

Explanation of Symbols

[0077] 1... Water treatment device, 10... Source, 11... Raw water pump, 12... Chemical injection device, 13... First filtration device, 14... Second filtration device, 14A, 14B, 14C... Filtration devices, 15... Treatment water tank, 16... Backwash pump, 17... Treatment water channel, 17a... Raw water channel (treatment water channel), 17b... Supply channel (treatment water channel), 17d... First treatment water channel (flow path), 17e... Treatment water channel (flow path), 18... Backwash water channel, 19, 19A, 19B... Drainage channels, 19a... Backwash drainage channel, 19b... Cleaning drainage channel, 19c... Test drainage channel, 20... Drainage channel, 20a... Backwash drainage channel, 20b... Cleaning drainage channel, 20c... Test drainage channel, 21... Chemical solution tank, 22... Injection pump, 30... Control panel, 30a... Control unit, 31... Filtration tank, 32... Suction pipe, 33... Recovery pipe, 33a... Recovery port, 34... Flow path switching unit, 35... Filtration tank, 36... Suction pipe, 37... Recovery pipe, 37a... Recovery port, 38... Flow path switching unit, 41 - 46... Three-way valves, 47... Bypass pipe, 47a... Bypass flow path, 48... On-off valve, 49... Check valve, 50... Feed water pump, 51... Nylon tube, 52... Tube coupling, 53... Bush, 54... Ball valve with check valve, 55... Ball valve, D1... Backwash drain, D2... Cleaning drain, D3... Test drain, D11... Backwash drain, D12... Cleaning drain, D13... Test drain, L1... First treated water, L2... Second treated water, L3... Backwash water, P1 - P9, P11 - P19... Ports, S1 - S17... On-off valves.

Claims

1. A first filtration device that removes iron or manganese contained in water by passing water therethrough; A chemical solution injection device that injects chlorine into raw water supplied to the first filtration device on the primary side of the first filtration device; A second filtration device that removes chlorine from the first treated water after filtration treatment on the secondary side of the first filtration device; A first treatment water passage through which the first treated water that has undergone the first filtration treatment flows from the first filtration device to the second filtration device, a second treatment water passage through which the second treated water that has undergone the second filtration treatment flows on the secondary side of the second filtration device, and a bypass passage that supplies the first treated water from the first treatment water passage to the second treatment water passage, and a water passage having the same; The second filtration device includes a filtration tank, a suction pipe connected to the filtration tank, a recovery pipe connected to the filtration tank, and a flow path switching means for switching a plurality of processes including a filtration process and a backwashing process by switching the connection state of the plurality of flow paths; The flow path switching means includes a first flow path switching valve, a second flow path switching valve, and a bypass pipe having one end connected between the first flow path switching valve and the suction pipe and the other end connected between the recovery pipe and the second flow path switching valve and constituting the bypass passage; The bypass pipe is provided with an on-off valve, a water treatment device.

2. A first filtration device that removes iron or manganese contained in water by passing water therethrough; A chemical solution injection device that injects chlorine into raw water supplied to the first filtration device on the primary side of the first filtration device; A second filtration device that removes chlorine from the first treated water after filtration treatment on the secondary side of the first filtration device; A first treatment water passage through which the first treated water that has undergone the first filtration treatment flows from the first filtration device to the second filtration device, a second treatment water passage through which the second treated water that has undergone the second filtration treatment flows on the secondary side of the second filtration device, and a bypass passage that supplies the first treated water from the first treatment water passage to the second treatment water passage, and a water passage having the same; The second filtration device includes a filtration tank, a suction pipe connected to the filtration tank, a recovery pipe connected to the filtration tank, and a flow path switching means for switching a plurality of processes including a filtration process and a backwashing process by switching the connection state of the plurality of flow paths; The flow path switching means includes a first flow path switching valve, a second flow path switching valve, and a bypass pipe having one end connected to the flow path on the primary side of the first flow path switching valve and the other end connected to the flow path on the secondary side of the second flow path switching valve and constituting the bypass passage; The bypass pipe is provided with an on-off valve, The first flow path switching valve connects the first treatment water channel and the suction pipe. The second flow path switching valve connects the recovery pipe and the second treatment water channel. Water treatment device.

3. The second filtration device has a filter medium containing activated carbon, The water treatment device according to claim 1 or 2, further comprising a concentration adjustment unit that injects a predetermined amount of a part of the first treated water into the second treated water through the bypass flow path.

4. The water treatment device according to claim 3, wherein the concentration adjustment unit adjusts the chlorine concentration by adjusting the flow rate through the bypass flow path.

5. The water treatment device according to claim 1 or 2, wherein the bypass pipe is provided with a check valve.

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