Water treatment system and method

Abstract

To purify raw water such as rainwater using a reverse osmosis membrane or the like, while providing a required amount of treated water at a required time.SOLUTION: A water treatment system includes: a raw water storage tank for storing raw water; first water conveyance means for conveying the raw water stored in the raw water storage tank; a reverse osmosis membrane for separating the conveyed raw water into permeated water and concentrated water; an activated carbon filter for filtering the permeated water; and a treated water storage tank for adding chlorine to water that has passed through the activated carbon filter, and storing the treated water.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to water treatment systems and methods. [Background technology]

[0002] A water purification device has been proposed that converts raw water from school pools, etc. into drinking water by reducing the residual chlorine content within a standard range (see Patent Document 1).

[0003] The purification device described in Patent Document 1 uses a reciprocating manual pump to suck up raw water, purify the sucked up raw water, and supply it. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP2018-176088A Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, a reverse osmosis membrane is used, but purification using a reverse osmosis membrane takes time and is not suitable when a predetermined amount of water is to be used immediately.

[0006] An object of the present disclosure is to purify raw water such as rainwater using a reverse osmosis membrane or the like, while providing the required amount of treated water at the required time. [Means for solving the problem]

[0007] A water treatment system comprising: a raw water storage tank for storing raw water; a first water supply means for supplying the raw water stored in the raw water storage tank; a reverse osmosis membrane for separating the supplied raw water into permeated water and concentrated water; an activated carbon filter for filtering the permeated water; and a treated water storage tank for adding chlorine to the water that has passed through the activated carbon filter and storing the water. Effect of the Invention

[0008] According to the present disclosure, raw water such as rainwater can be purified using a reverse osmosis membrane or the like, while the required amount of treated water can be provided at the required time. [Brief description of the drawings]

[0009] [Figure 1] 1 is a block diagram showing an example of the configuration of a system according to an embodiment of the present invention. [Diagram 2] 4 is a flowchart showing an example of the operation of the control device 36 when purifying raw water stored in the raw water storage tank 21. [Diagram 3] 13 is a flowchart showing an example of the operation of the control device 36 when the treated water stored in the treated water storage tank 31 is sent to the raw water storage tank 21. [Figure 4] 1 is a graph showing the transition of TOC and TN when an activated carbon filter 18 is installed and when it is not installed. [Diagram 5] FIG. 13 is a block diagram showing another example of the configuration of the system according to the embodiment. [Figure 6] 13 is a flowchart showing another example of the operation of the control device 36 when the treated water stored in the treated water storage tank 31 is sent to the raw water storage tank 21. [Figure 7] 13 is a flowchart showing another example of the operation of the control device 36 when purifying raw water stored in the raw water storage tank 21. [Figure 8] FIG. 2 is a block diagram showing the basic hardware configuration of a computer 90. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings for explaining the embodiment, the same components are generally designated by the same reference numerals, and the repeated description will be omitted.

[0011] <Summary> The system according to the present embodiment uses treated water, obtained by filtering raw water such as rainwater, surface water, and groundwater, as drinking water or water for daily use. In the present embodiment, drinking water may include water used for washing, cooking, and the like. In the present embodiment, daily use water refers to water used in daily life, such as bathing, showering, laundry, and dishwashing. The system separates raw water stored in a raw water storage tank into permeated water and concentrated water using a reverse osmosis membrane. The system passes the permeated water through an activated carbon filter and supplies it to a treated water storage tank. Chlorine is added to the treated water storage tank to suppress the growth of bacteria. The system measures the chlorine concentration in the treated water storage tank, and if the chlorine concentration does not reach a predetermined value, returns the water in the treated water storage tank to the raw water storage tank.

[0012] <System configuration> The overall configuration of a system 1 according to this embodiment will be described.

[0013] Fig. 1 is a block diagram showing an example of the configuration of a system according to this embodiment. In Fig. 1, the system 1 is installed, for example, indoors, outdoors, or both, of a building 100. The outdoors of the building 100 includes, for example, the basement of the building 100. A part of the system 1 may be buried underground. In Fig. 1, an example will be described in which the raw water is rainwater taken by the building 100, but the raw water is not limited to rainwater.

[0014] The building 100 includes, for example, a rain gutter 101 and a dust cover 102. Rain that falls on the building 100 flows down the rain gutter 101 and is collected, and the dust cover 102 removes dust from the rain water before the water is taken in.

[0015] For example, a raw water storage tank 21 is installed inside the building 100. The raw water storage tank 21 may be installed outside the building 100. The raw water storage tank 21 is a tank (tank) that stores raw water to be supplied. The raw water storage tank 21 has a capacity that can store raw water sufficient for several families to live for several days, for example. Rainwater taken in through a rain gutter 101 and a garbage guard 102 is supplied to the raw water storage tank 21. Water discharged by a pump 24 is also supplied to the raw water storage tank 21.

[0016] An ozone generator 22, for example, is installed in the raw water storage tank 21. The ozone generator 22 generates ozone gas for, for example, sterilizing the water in the raw water storage tank 21. The ozone generator 22 supplies the generated ozone gas to the raw water storage tank 21. Specifically, the ozone generator 22 supplies the ozone gas into the raw water in the raw water storage tank 21, i.e., into the liquid phase of the raw water storage tank 21. The ozone generator 22 may also supply the ozone gas to the gas phase of the raw water storage tank 21.

[0017] Methods for generating ozone gas using the ozone generator 22 include, for example, a discharge method (silent discharge method), an electrolysis method (water electrolysis cell method), and an ultraviolet method (mercury UV lamp method / mercury-free UV lamp (excimer lamp) method). Of these, the ultraviolet method (mercury-free UV lamp (excimer lamp) method) is preferred. The ultraviolet method (mercury-free UV lamp (excimer lamp) method) does not generate harmful nitrogen oxides from nitrogen present in the atmosphere when generating ozone gas, and can generate ozone gas with few impurities. Therefore, it is particularly suitable as a method to be adopted in an ozone generator to be mounted on a small system installed in a home or the like.

[0018] By generating ozone gas with fewer impurities, it is possible to reduce the operating time of the ozone generator 22, suppress power consumption, and extend the life of the ozone generator 22. By generating ozone gas with fewer impurities, it is possible to reduce the size of the system equipment and reduce the number of deteriorated and damaged parts, which also leads to a reduction in the frequency of maintenance.

[0019] A water level meter (not shown) is installed in the raw water storage tank 21. The water level meter detects the water level in the raw water storage tank 21, for example, by measuring the electric potential. For example, when a predetermined first water level is detected by the water level meter, the drain is opened to discharge the treated water in the raw water storage tank 21, and when the water level reaches a predetermined second water level, the drain is closed.

[0020] A pump 23 is attached to a pipe connected to the raw water storage tank 21. The pump 23 is driven under the control of the control device 36 of the system 1, and sends out the raw water stored in the raw water storage tank 21 to the membrane treatment module 10.

[0021] The membrane treatment module 10 is a free-standing membrane treatment module and can be installed in various locations, such as indoors and outdoors. Specifically, the membrane treatment module 10 has, for example, a plurality of replaceable filter cartridges attached thereto. The membrane treatment module 10 is arranged indoors in the building 100 so that a user can replace a filter cartridge that has reached its expiration date while staying in the building 100. The membrane treatment module 10 may also be arranged outdoors, for example, when there is no space in the building 100. The membrane treatment module 10 may have a moving mechanism such as wheels and be configured to be movable. In this case, even if the membrane treatment module 10 is once arranged in a predetermined position, the arrangement can be changed at any time.

[0022] The membrane treatment module 10 includes a conductivity sensor 11, a pressure sensor 12, a first filter 13, a sensor group 15, a reverse osmosis membrane 16, a sensor group 17, an activated carbon filter 18, a valve 19, and a wastewater storage tank 110. Note that the configuration of the membrane treatment module 10 is not limited to these. For example, the membrane treatment module 10 may include devices other than these, or may not include any of these devices.

[0023] The conductivity sensor 11 detects the electrical conductivity of the water discharged from the pump 23 and supplied to the membrane treatment module 10. The pressure sensor 12 detects the pressure of the water discharged from the pump 23 and supplied to the membrane treatment module 10.

[0024] The first filter 13 removes, for example, solids and / or water pollutants from the water pumped out from the pump 23. In this embodiment, a thread-wound filter is used as the first filter 13, but the present invention is not limited to this. For example, at least one of a sediment filter, a microfiltration membrane (MF), an ultrafiltration membrane (UF), a nanofiltration membrane (NF), a ceramic filter, an ion exchange filter, and a metal membrane may be selected.

[0025] The sensor group 15 is disposed upstream of the reverse osmosis membrane 16. The sensor group 15 detects components, physical properties, and the like of the water supplied to the reverse osmosis membrane 16. In the illustrated example, the sensor group 15 includes a pressure sensor, a flow rate sensor, and a conductivity sensor.

[0026] The pressure sensor detects the pressure of the water supplied to the reverse osmosis membrane 16. The flow rate sensor detects the flow rate of the water supplied to the reverse osmosis membrane 16. The conductivity sensor detects the electrical conductivity of the water supplied to the reverse osmosis membrane 16.

[0027] In addition to the above-mentioned sensors, the sensor group 15 may have a sensor that senses at least one of the following: (1) pH, oxidation-reduction potential, alkalinity, ion concentration, hardness (2) Turbidity, color, viscosity, dissolved oxygen (3) Odor, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, total nitrogen, residual chlorine, total phosphorus, total organic carbon, total inorganic carbon, total trihalomethanes (4) Detection results of microbial sensors, chemical oxygen demand, biological oxygen demand, (5) Cyanide, mercury, oil, surfactants (6) Detection results of optical sensors and TDS (Total Dissolved Solids) sensors (7) Mass spectrometry results, fine particles, zeta potential, surface potential

[0028] The reverse osmosis membrane 16 separates the supplied water into permeate from which dissolved components have been removed and concentrated water from which dissolved components have been concentrated. The reverse osmosis membrane 16 is, for example, a spiral reverse osmosis membrane. The reverse osmosis membrane 16 is, for example, an example of a cross-flow type filtration membrane. The cross-flow type filtration membrane refers to a filtration membrane that performs filtration while suppressing deposition of suspended matter and colloids in the wastewater supplied to the membrane on the membrane surface by creating a flow parallel to the membrane surface. In other words, the cross-flow type filtration membrane refers to a membrane that performs filtration by pumping wastewater at a pressure higher than the osmotic pressure of the membrane. As such a cross-flow type filtration membrane, a nanofiltration membrane (NF membrane), an ultrafiltration membrane (UF membrane), a microfiltration membrane (MF membrane), or the like may be adopted instead of a reverse osmosis membrane. The permeate separated by the reverse osmosis membrane 16 is supplied to the sensor group 17. The concentrated water separated by the reverse osmosis membrane 16 is discharged to the wastewater storage tank 110 via a valve 19. The concentrated water stored in the wastewater storage tank 110 is used, for example, as toilet flush water, emergency water, laundry water, etc. The wastewater storage tank 110 may be called, for example, a miscellaneous wastewater storage tank.

[0029] The sensor group 17 is disposed after the reverse osmosis membrane 16. The sensor group 17 detects components or physical properties of the permeated water separated by the reverse osmosis membrane 16. In the illustrated example, the sensor group 17 includes a conductivity sensor, a flow rate sensor, and a pressure sensor.

[0030] The conductivity sensor detects the electrical conductivity of the permeated water separated by the reverse osmosis membrane 16. The pressure sensor detects the pressure of the permeated water separated by the reverse osmosis membrane 16. The flow rate sensor detects the flow rate of the permeated water separated by the reverse osmosis membrane 16.

[0031] The sensor group 17 may have sensors that sense at least one of the sensors (1) to (7) shown in the sensor group 15, in addition to the above-mentioned sensors.

[0032] The permeated water immediately after the reverse osmosis membrane 16 is put into operation is measured by the sensor group 17 and then supplied to the wastewater storage tank 110 until a predetermined requirement is met. For example, a predetermined valve is attached to switch the flow path. The predetermined requirement is, for example, that the quality of the permeated water is stable (for example, that the value of the conductivity sensor of the sensor group 17 is stable), or that the value of the conductivity sensor of the sensor group 17 is smaller than the value of the conductivity sensor of the sensor group 15, etc.

[0033] The activated carbon filter 18 is disposed, for example, downstream of the reverse osmosis membrane 16 via the sensor group 17. The activated carbon filter 18 removes, for example, organic matter that may be contained in the permeated water discharged from the reverse osmosis membrane 16. Due to a creep phenomenon of the reverse osmosis membrane 16, organic matter may be mixed into the permeated water supplied from the reverse osmosis membrane 16. The activated carbon filter 18 prevents organic matter that may be contained in the permeated water from reaching the treated water storage tank 31. The water that has passed through the activated carbon filter 18 is discharged into the treated water storage tank 31.

[0034] Information detected by the conductivity sensor 11, the pressure sensor 12, the sensor group 15, and the sensor group 17 is stored in a memory unit (not shown) installed in the membrane treatment module 10. The information stored in the memory unit is output in response to a specified request. The information may be output via a medium attached to a specified interface, or may be output in accordance with a specified protocol by a communication unit (not shown) installed in the membrane treatment module 10. The information may be output in response to an instruction from a user, or may be automatically output at a specified cycle.

[0035] The treated water storage tank 31 is installed, for example, indoors of the building 100. The treated water storage tank 31 may be installed outdoors of the building 100. The treated water storage tank 31 is a tank (tank) that stores the treated water to be supplied. The treated water storage tank 31 has a capacity capable of storing treated water sufficient for several families to live in for several days, for example. The treated water storage tank 31 may have a capacity similar to that of the raw water storage tank 21. The treated water that has passed through the activated carbon filter 18 is supplied to the treated water storage tank 31.

[0036] A chlorine meter 32 is installed in the treated water storage tank 31. The chlorine meter 32 measures the residual chlorine concentration in the treated water stored in the treated water storage tank 31. The residual chlorine concentration gradually decreases over time after a chlorine-based chemical (hereinafter referred to as chlorine water) is supplied. The chlorine-based chemical is, for example, a chemical with a disinfecting effect, such as sodium hypochlorite or hypochlorous acid water.

[0037] Chlorine water is supplied to the treated water storage tank 31 from the chlorine supply unit 33. The chlorine supply unit 33 is realized by, for example, a chlorine tank and a chlorine pump. The chlorine tank is a tank for storing chlorine water. The chlorine water is generated, for example, by dissolving hypochlorous acid tablets in water supplied to the chlorine tank. The chlorine water may also be generated by dissolving salt in the water supplied to the chlorine tank and electrolyzing the salt water. An electrolysis unit that electrolyzes the salt water to generate chlorine water may be provided separately downstream of the chlorine tank.

[0038] The chlorine pump is driven under the control of the control device 36, and adds chlorine water stored in the chlorine tank to the treated water storage tank 31. Specifically, for example, the control device 36 drives the chlorine pump so that the residual chlorine concentration in the treated water storage tank 31 at the initial stage after purification exceeds a predetermined value. In other words, the control device 36 adds a preset amount of chlorine water to the treated water storage tank 31 at the initial stage after purification. The predetermined value is set to 1 ppm based on 0.1 ppm, which is the tap water quality standard value. Note that the predetermined value is not limited to 1 ppm, and may be another value. For example, the predetermined value may be 2 ppm. In addition, the control device 36 drives the pump 24, and drives the chlorine pump so that the residual chlorine concentration in the treated water storage tank 31 after circulation exceeds a predetermined value when the treated water stored in the treated water storage tank 31 is circulated through the raw water storage tank 21 and stored in the treated water storage tank 31. In other words, the control device 36 adds a preset amount of chlorine water to the treated water storage tank 31 after circulation.

[0039] The chlorine water may be added to the treated water that has passed through the activated carbon filter 18, rather than being added directly to the treated water storage tank 31. In this case, the treated water to which the chlorine water has been added is supplied to the treated water storage tank 31.

[0040] A water level gauge (not shown) is installed in the treated water storage tank 31. The water level gauge detects the water level in the treated water storage tank 31, for example, by measuring the electric potential. For example, when the water level gauge detects a predetermined first water level, the drain is opened to discharge the treated water in the treated water storage tank 31, and when the water level reaches a predetermined second water level, the drain is closed.

[0041] A pipe is connected to the treated water storage tank 31 for supplying treated water to consumers living in the building 100. A pump 34 is attached to this pipe. The pump 34 is driven under the control of the control device 36, and supplies the treated water stored in the treated water storage tank 31 to the consumers living in the building 100. Specifically, for example, when the control device 36 detects a request signal for treated water from a consumer in the building 100, it drives the pump 34. The request signal for treated water from the consumer is, for example, as follows. - A request to supply treated water to the treated water outlet (for example, turning on a faucet, approaching an infrared sensor installed at the outlet, etc.) Requests for operations of devices such as washing machines, bathtubs, toilets, and dishwashers (e.g., pressing a button) - Requests for the supply of treated water based on scheduled operations set for devices such as washing machines and bathtubs

[0042] The UV sterilization unit 35 is disposed between the treated water storage tank 31 and the pump 34. The UV sterilization unit 35 irradiates the treated water drawn from the treated water storage tank 31 with ultraviolet light, thereby sterilizing the water. The treated water that has passed through the UV sterilization unit 35 is supplied to a consumer.

[0043] The sensor 37 is installed after the pump 34. The sensor 37 detects whether or not water has been supplied to the consumer. Specifically, the sensor 37 is realized by, for example, a capacitance sensor that detects capacitance in the piping. When the pump 34 is driven and treated water is supplied to the consumer, the sensor 37 detects that water has been supplied to the consumer based on a change in capacitance. The sensor 37 may be installed at a drain outlet on the consumer side, instead of between the pump 34 and the consumer. A filter for removing a predetermined component may be installed between the pump 34 and the consumer.

[0044] A pipe is connected between the treated water storage tank 31 and the raw water storage tank 21 to supply the treated water stored in the treated water storage tank 31 to the raw water storage tank 21. A pump 24 is attached to this pipe. The pump 24 is driven under the control of the control device 36 to supply the treated water stored in the treated water storage tank 31 to the raw water storage tank 21. For example, the control device 36 drives the pump 24 when the residual chlorine concentration measured by the chlorine meter 32 is less than a predetermined threshold. In addition, the control device 36 drives the pump 24 when the amount of water in the treated water storage tank 31 becomes equal to or less than a predetermined amount. The predetermined amount may represent, for example, that the treated water is almost depleted in the treated water storage tank 31. Specifically, for example, the control device 36 drives the pump 24 when the water level in the treated water storage tank 31 reaches a predetermined water level.

[0045] For example, the control device 36 drives the pump 24 until the raw water storage tank 21 is filled with water. The control device 36 may also drive the pump 24 until the treated water storage tank 31 reaches a predetermined water level. The predetermined water level here may include the water level being approximately zero. The control device 36 may also drive the pump 24 to send out a predetermined volume of treated water stored in the treated water storage tank 31 to the raw water storage tank 21.

[0046] When the raw water storage tank 21 becomes full by supplying treated water from the treated water storage tank 31 to the raw water storage tank 21, the surplus water sent from the treated water storage tank 31 is used, for example, outdoors. Specifically, the surplus water is used, for example, as water for washing and cleaning daily utensils, watering garden trees, sprinkling water, watering a biotope, and landscaping water. When the raw water storage tank 21 becomes full by supplying treated water from the treated water storage tank 31 to the raw water storage tank 21, the control device 36, for example, drives the pump 23 to purify the raw water in the raw water storage tank 21. In addition, when the raw water storage tank 21 becomes full by supplying treated water from the treated water storage tank 31 to the raw water storage tank 21, the control device 36 may stop the pump 24 and open the drain of the raw water storage tank 21 to release the raw water stored in the raw water storage tank 21. After discharging the raw water from the raw water storage tank 21, the control device 36 resumes driving the pump 24 and supplies treated water from the treated water storage tank 31 to the raw water storage tank 21. Furthermore, when the raw water storage tank 21 becomes full due to the supply of treated water from the treated water storage tank 31 to the raw water storage tank 21, the control device 36 may stop the pump 24 and open the drain of the treated water storage tank 31.

[0047] The control device 36 is realized by the processor reading out a program stored in the storage, expanding it on the memory, and executing the instructions included in the expanded program. The processor is hardware for executing an instruction set described in the program, and is composed of an arithmetic unit, a register, a peripheral circuit, etc. The storage is a storage device for saving data, such as a flash memory or a hard disk drive (HDD). The memory is for temporarily storing programs and data processed by the programs, etc., and is a volatile memory, such as a dynamic random access memory (DRAM).

[0048] The control device 36 controls, for example, the operation of the pumps 23, 24, and 34. The control device 36 also controls, for example, the operation of the chlorine pump of the chlorine supply unit 33.

[0049] <Operation> The control process in the system 1 will be described.

[0050] (Raw water purification treatment) Fig. 2 is a flowchart showing an example of the operation of the control device 36 when purifying raw water stored in the raw water storage tank 21. The control device 36 executes the process shown in Fig. 2, for example, when purifying raw water for the first time after starting up the system 1, or when purifying raw water after moving treated water from the treated water storage tank 31 to the raw water storage tank 21. The raw water storage tank 21 stores, for example, rainwater. The control device 36 drives the ozone generator 22 at a predetermined timing, for example, to sterilize the raw water in the raw water storage tank 21 with ozone.

[0051] Specifically, first, in step S11, the control device 36 drives the pump 23. Specifically, for example, the control device 36 drives the pump 23 in response to an instruction from a user. For example, the user confirms that a sufficient amount of raw water has accumulated in the raw water storage tank 21, and instructs the start of purification of the raw water. The user's instruction may be a reservation to start purification that is executed on the condition that the raw water accumulates to a predetermined water level. Also, for example, the user may confirm that the treated water in the treated water storage tank 31 has reached a predetermined water level, and instructs the start of purification of the raw water. The user's instruction may be a reservation to start purification that is executed on the condition that the treated water in the treated water storage tank 31 has reached a predetermined water level.

[0052] When the pump 23 is driven, raw water is supplied from the raw water storage tank 21 to the membrane treatment module 10. The membrane treatment module 10 removes, for example, solids and / or water pollutants contained in the raw water using a first filter 13. The membrane treatment module 10 separates the water treated by the first filter 13 into permeated water and concentrated water using a reverse osmosis membrane 16. The membrane treatment module 10 removes organic matter contained in the permeated water separated by the reverse osmosis membrane 16 using an activated carbon filter 18. The membrane treatment module 10 supplies the purified water to a treated water storage tank 31.

[0053] In step S12, the control device 36 judges whether the water level in the treated water storage tank 31 has reached a predetermined value. Specifically, for example, a water level gauge is attached to the treated water storage tank 31 at a position where the predetermined water level can be detected. When the water level in the treated water storage tank 31 reaches the predetermined water level, the water level gauge transmits a detection signal to the control device 36. When the control device 36 receives the detection signal, it judges that the water level in the treated water storage tank 31 has reached the predetermined value. If it is judged that the water level in the treated water storage tank 31 has reached the predetermined value, the control device 36 shifts the process to step S13. If it is not judged that the water level in the treated water storage tank 31 has reached the predetermined value, the control device 36 shifts the process to step S11 and maintains the operation of the pump 23.

[0054] In step S13, the control device 36 stops the pump 23. As a result, the control device 36 continuously purifies the raw water until a predetermined amount of treated water is stored in the treated water storage tank 31, and stores the treated water in the treated water storage tank 31. Since the raw water in the raw water storage tank 21 is purified all at once at a predetermined timing until the treated water storage tank 31 is substantially full, the operation of the pump is suppressed, and it is possible to reduce the amount of electricity used.

[0055] In step S14, the control device 36 drives the chlorine supply unit 33. Specifically, the control device 36 drives the chlorine pump of the chlorine supply unit 33. When driven by the control device 36, the chlorine pump adds chlorine water stored in the chlorine tank to the treated water storage tank 31.

[0056] In step S15, the control device 36 judges whether the residual chlorine concentration in the treated water storage tank 31 has reached a predetermined value. Specifically, for example, the chlorine meter 32 measures the residual chlorine concentration of the treated water stored in the treated water storage tank 31 and transmits the measurement result to the control device 36. The control device 36 refers to the measurement result transmitted from the chlorine meter 32 and judges whether the residual chlorine concentration in the treated water storage tank 31 has reached a predetermined value, for example, 1 ppm based on the tap water quality standard value of 0.1 ppm. If the residual chlorine concentration in the treated water storage tank 31 has reached the predetermined value, the control device 36 shifts the process to step S16. If the residual chlorine concentration in the treated water storage tank 31 has not reached the predetermined value, the control device 36 shifts the process to step S14 and maintains the operation of the chlorine pump.

[0057] In step S15, the control device 36 may determine whether or not a preset amount of chlorine water has been added to the treated water storage tank 31. If the preset amount of chlorine water has been added to the treated water storage tank 31, the control device 36 shifts the process to step S16. If the preset amount of chlorine water has not been added to the treated water storage tank 31, the control device 36 shifts the process to step S14 and maintains the operation of the chlorine pump.

[0058] In step S16, the control device 36 stops the chlorine pump, thereby causing the residual chlorine concentration of the treated water stored in the treated water storage tank 31 to reach a predetermined value.

[0059] In the description of FIG. 2, the control device 36 stops the pump 23 in step S13, and then drives the chlorine pump in step S14. However, the control device 36 may execute an operation other than step S14 after stopping the pump 23 in step S13. For example, the control device 36 may measure the residual chlorine concentration of the treated water after circulation stored in the treated water storage tank 31 by the chlorine meter 32 after stopping the pump 23 in step S13. For example, if the residual chlorine concentration measured at this time is less than 0.1 ppm, which is the tap water quality standard value, the control device 36 determines that an abnormality has occurred and stops all operations of the system 1. The control device 36 stores the sensing data measured by the membrane treatment module 10 when it is determined that an abnormality has occurred as data at the time of the abnormality occurrence.

[0060] (Circulation process) Fig. 3 is a flowchart showing an example of the operation of the control device 36 when the treated water stored in the treated water storage tank 31 is sent to the raw water storage tank 21. For example, in the system 1, the control device 36 executes the process shown in Fig. 3 when a sufficient amount of treated water is stored in the treated water storage tank 31 and the system 1 is in a normal operating state.

[0061] In step S31, the controller 36 stops the pump 24.

[0062] In step S32, the control device 36 judges whether the residual chlorine concentration of the treated water in the treated water storage tank 31 is less than a predetermined value. The residual chlorine concentration of the treated water in the treated water storage tank 31 decreases over time and due to other environmental factors. In this embodiment, the residual chlorine concentration is set so that it does not become less than a predetermined value even after a predetermined period of time has passed under normal circumstances. When the chlorine meter 32 detects that the residual chlorine concentration is less than the predetermined value, the control device 36 shifts the process to step S33. When the residual chlorine concentration is equal to or greater than the predetermined value, the control device 36 shifts the process to step S34. The chlorine meter 32 measures the residual chlorine concentration at a predetermined cycle, for example, once a day.

[0063] In step S33, the control device 36 drives the pump 24. The pump 24 sucks treated water from the treated water storage tank 31 and sends the sucked treated water to the raw water storage tank 21. After driving the pump 24, the control device 36 transitions the process to step S36.

[0064] In step S34, the control device 36 judges whether the water level of the treated water in the treated water storage tank 31 has reached a predetermined value. In other words, the control device 36 judges whether the amount of treated water in the treated water storage tank 31 has reached a predetermined amount. Specifically, for example, a water level gauge is attached to the treated water storage tank 31 at a position where a predetermined water level (a water level indicating that the water is almost gone) can be detected. When the water level in the treated water storage tank 31 reaches the predetermined water level, the water level gauge transmits a detection signal to the control device 36. When the control device 36 receives the detection signal, it judges that the water level in the treated water storage tank 31 has reached a predetermined value. When it is judged that the water level in the treated water storage tank 31 has reached the predetermined value, the control device 36 shifts the process to step S35. When it is not judged that the water level in the treated water storage tank 31 has reached the predetermined value, the control device 36 shifts the process to step S31 and keeps the pump 24 stopped.

[0065] In step S35, the control device 36 drives the pump 24. When driven, the pump 24 sucks treated water from the treated water storage tank 31 and sends the sucked treated water to the raw water storage tank 21. After driving the pump 24, the control device 36 transitions the process to step S36.

[0066] In step S36, the control device 36 judges whether the water level of the treated water in the treated water storage tank 31 has reached a predetermined value. Specifically, when the pump 24 is driven, the treated water in the treated water storage tank 31 is sucked in, so that the water level of the treated water in the treated water storage tank 31 decreases. The water level gauge in the treated water storage tank 31 detects that the treated water in the treated water storage tank 31 has reached a predetermined water level. The predetermined water level may be zero or another water level. When the water level gauge detects that the predetermined water level has been reached, it transmits a detection signal. When the control device 36 receives a detection signal from the water level gauge, it judges that the water level of the treated water in the treated water storage tank 31 has reached a predetermined value, shifts the process to step S31, and stops the pump 24. When there is no detection signal from the water level gauge, the control device 36 judges that the water level of the treated water in the treated water storage tank 31 has not reached a predetermined value, shifts the process to step S35, and keeps the pump 24 driven.

[0067] As a result, treated water is supplied from the treated water storage tank 31 to the raw water storage tank 21 until the treated water level in the treated water storage tank 31 reaches a predetermined value. When the raw water storage tank 21 becomes full due to the supply of treated water from the treated water storage tank 31 to the raw water storage tank 21, the control device 36 may stop the pump 24. In this case, the drain of the raw water storage tank 21 may be opened to release the raw water stored in the raw water storage tank 21, and then the operation of the pump 24 may be resumed to supply the treated water from the treated water storage tank 31 to the raw water storage tank 21.

[0068] As described above, in the above embodiment, the raw water storage tank 21 stores raw water. The pump 23 draws in the raw water stored in the raw water storage tank 21 and delivers the raw water. The reverse osmosis membrane 16 separates the delivered raw water into permeated water and concentrated water. The activated carbon filter 18 filters the permeated water. The treated water storage tank 31 adds chlorine to the water that has passed through the activated carbon filter 18 and stores the water. As a result, treated water purified by the reverse osmosis membrane 16 and the activated carbon filter 18 is stored in the treated water storage tank 31 in advance of demand.

[0069] Therefore, according to the above embodiment, raw water such as rainwater can be purified using a reverse osmosis membrane or the like, while a required amount of treated water can be provided at a required timing.

[0070] Furthermore, by installing the activated carbon filter 18 after the reverse osmosis membrane 16, it becomes possible to prevent organic matter generated by creep of the reverse osmosis membrane 16 from reaching the treated water storage tank 31. This makes it possible to reduce the amount of disinfectant (chlorine water) added to the treated water storage tank 31. This makes it possible to prevent adverse effects caused by excessive addition of disinfectant, such as an increase in salt concentration in the water circulation system (an increase in Na salt derived from sodium hypochlorite) and the generation of by-products (chloroacetic acid, trihalomethanes, chloric acid, etc.).

[0071] Fig. 4 is a graph showing the transition of TOC (total organic carbon) and TN (total nitrogen) when the activated carbon filter 18 is installed and when it is not installed. The graph shown in Fig. 4 shows the results of measuring the TOC and TN of the treated water stored in the treated water storage tank 31 using a TOC / TN meter. In Fig. 4, the horizontal axis represents the number of times the reverse osmosis membrane 16 has been operated, and the vertical axis represents TOC and TN. In Fig. 4, the solid line represents the TOC when the activated carbon filter 18 is installed, the dashed line represents the TN when the activated carbon filter 18 is installed, the one-dot chain line represents the TOC when the activated carbon filter 18 is not installed, and the two-dot chain line represents the TN when the activated carbon filter 18 is not installed.

[0072] 4, the TOC and TN values ​​of the treated water stored in the treated water storage tank 31 differ depending on whether or not the activated carbon filter 18 is installed. By installing the activated carbon filter 18 downstream of the reverse osmosis membrane 16, TOC and TN are removed, and the treated water stored in the treated water storage tank 31 becomes water of better quality than when the activated carbon filter 18 is not installed.

[0073] In the above embodiment, when the chlorine concentration of the water stored in the treated water storage tank 31 does not reach a predetermined concentration, the pump 24 sends the water stored in the treated water storage tank 31 to the raw water storage tank 21. In other words, when the chlorine concentration in the treated water storage tank 31 becomes less than a threshold value, the water is sent to the raw water storage tank 21 and purification is performed again by the membrane treatment module 10, instead of adding additional disinfectant such as chlorine water. Water contamination due to a lack of chlorine can be almost completely purified by circulating treatment. In addition, by adding a necessary and sufficient amount of chlorine after storing the treated water in the treated water storage tank 31, it is possible to suppress the amount of chlorine added (used) in the entire circulation system. This makes it possible to maintain good water quality while suppressing the amount of chlorine added. In addition, it is possible to suppress an increase in the Na ion concentration derived from chlorine-based chemicals in the rainwater treatment system due to the excessive addition of chlorine-based chemicals with a disinfecting effect.

[0074] <Modification> In the above embodiment, the reverse osmosis membrane 16 performs separation of permeate and concentrated water from the raw water once when the raw water sent from the raw water storage tank 21 is supplied to the treated water storage tank 31 as treated water. The process of the reverse osmosis membrane 16 is not limited to one time when the raw water sent from the raw water storage tank 21 is purified and supplied to the treated water storage tank 31. For example, the required water quality differs depending on what the treated water is used for. As shown in FIG. 5, the permeate separated by the reverse osmosis membrane 16 may be passed through the reverse osmosis membrane 16 again depending on the required water quality. More specifically, for example, when the treated water is used as water for daily life, separation by the reverse osmosis membrane 16 is performed once. On the other hand, when the treated water is used as drinking water, the water quality needs to be improved. Therefore, when the treated water is used as drinking water, the permeate separated by the reverse osmosis membrane 16 is returned to the reverse osmosis membrane 16 a set number of times, and the separation process is repeated to improve the water quality of the permeate. The number of times of treatment by the reverse osmosis membrane 16 may be three or more, and is not necessarily limited to two. Furthermore, the treatment by the reverse osmosis membrane 16 may be repeated based on predetermined sensing data, without being limited to a preset number of times.

[0075] In the above embodiment, an example has been described in which only one treated water storage tank 31 is installed. However, the number of treated water storage tanks 31 installed in the system 1 is not limited to one. Separate treated water storage tanks 31 may be installed depending on the purpose, such as drinking water and water for daily use. Specifically, there may be a treated water storage tank for storing drinking water, and another treated water storage tank for storing water for daily use.

[0076] In the above embodiment, the circulation process is performed based on the residual chlorine concentration detected by the chlorine meter 32. However, the circulation process is not limited to the one based on the residual chlorine concentration. For example, when chlorine water is added so that the residual chlorine concentration in the treated water storage tank 31 in the early stage after purification exceeds a predetermined value, the residual chlorine concentration is set not to be below a predetermined threshold value for a predetermined period under a general environment. In this embodiment, the predetermined threshold value refers to, for example, 0.1 ppm, which is the tap water quality standard value. Also, the predetermined value is, for example, 1 ppm, which is set based on 0.1 ppm. In this case, the predetermined period can be set to, for example, one week (7 days). For example, the control device 36 drives the pump 24 when the predetermined period has elapsed.

[0077] Fig. 6 is a flow chart showing another example of the operation of the control device 36 when the treated water stored in the treated water storage tank 31 is sent to the raw water storage tank 21. In Fig. 6, the same processes as those in Fig. 3 are denoted by the same reference numerals.

[0078] In step S41, the control device 36 judges whether a predetermined period has elapsed. The target value of the residual chlorine concentration to be achieved by adding chlorine water and the predetermined period are set based on a threshold value for the residual chlorine concentration. In other words, under normal circumstances, if the residual chlorine concentration reaches the target value by adding chlorine water, the residual chlorine concentration is set not to fall below the threshold value even if the predetermined period has elapsed. Therefore, if the treated water stored in the treated water storage tank 31 is purified by the membrane treatment module 10 every predetermined period, the treated water will be maintained clean.

[0079] The control device 36 determines whether or not a predetermined period of time has elapsed since the treated water was previously sent from the treated water storage tank 31 to the raw water storage tank 21. In this embodiment, the predetermined period of time is, for example, seven days. If the predetermined period of time has elapsed, the control device 36 shifts the process to step S33. If the predetermined period of time has not elapsed, the control device 36 shifts the process to step S31 and keeps the pump 24 stopped.

[0080] In the above embodiment, the case where the raw water stored in the raw water storage tank 21 is purified when the raw water storage tank 21 becomes full or the amount of storage in the treated water storage tank 31 becomes low has been described as an example. However, the timing of purifying the raw water is not limited to these. The control device 36 may drive the pump 23 when the treated water in the treated water storage tank 31 is used, and purify the raw water. Specifically, for example, the control device 36 drives the pump 23 when it detects that the treated water stored in the treated water storage tank 31 has been supplied to a consumer living in the building 100.

[0081] Fig. 7 is a flowchart showing another example of the operation of the control device 36 when purifying raw water stored in the raw water storage tank 21. Fig. 7 shows the operation when the raw water stored in the raw water storage tank 21 is purified by the membrane treatment module 10 in accordance with the use of the treated water stored in the treated water storage tank 31. The control device 36 executes the process shown in Fig. 7 when, for example, in the system 1, a sufficient amount of treated water is stored in the treated water storage tank 31 and the system is in a normal operating state.

[0082] In step S21, the control device 36 stops the pump 23.

[0083] In step S22, the control device 36 judges whether water has been detected by the sensor 37. Specifically, for example, an infrared sensor is installed at a water outlet installed in the building 100. When a consumer uses water, the consumer approaches the water outlet and causes the infrared sensor to detect the consumer. When the infrared sensor detects a consumer, it transmits a detection signal to the control device 36. When the control device 36 receives the detection signal, it judges that a request signal has been received from the consumer. When the control device 36 receives the detection signal, it drives the pump 34. When the pump 34 is driven by the control device 36, it draws treated water from the treated water storage tank 31 via the UV sterilization unit 35. The pump 34 supplies the drawn treated water to the consumer via the sensor 37.

[0084] The sensor 37 detects that water has flowed based on a change in capacitance. When the sensor 37 detects water, it transmits a detection signal to the control device 36. When the control device 36 receives a detection signal from the sensor 37, it determines that water has been detected by the sensor 37, and shifts the process to step S23. When the control device 36 does not receive a detection signal from the sensor 37, it determines that water has not been detected by the sensor 37, and shifts the process to step S21, and keeps the pump 23 stopped.

[0085] In step S23, the control device 36 drives the pump 23.

[0086] In step S24, the control device 36 determines whether water has been detected by the sensor 37. Specifically, for example, when the consumer has finished using water, he or she removes his or her hand from the water outlet. When the hand is removed from the water outlet, the infrared sensor no longer detects the consumer. When the infrared sensor no longer detects the consumer, it stops the detection signal. When the detection signal is stopped, the control device 36 stops the pump 34.

[0087] The sensor 37 detects that the supply of water has stopped based on the change in capacitance. When the sensor 37 detects that the supply of water has stopped, it stops the detection signal. When the detection signal from the sensor 37 stops, the control device 36 determines that water is not being detected by the sensor 37, shifts the process to step S21, and stops the pump 23. When the control device 36 is receiving a detection signal from the sensor 37, it determines that water is being detected by the sensor 37, shifts the process to step S23, and maintains the operation of the pump 23.

[0088] As a result, while water is being supplied to the consumer, raw water is supplied from the raw water storage tank 21 to the membrane treatment module 10. Furthermore, for example, by controlling the pumps 23 and 34 so that the flow rate of raw water sent out by the pump 23 and the flow rate of treated water sent out by the pump 34 are substantially the same, raw water is sent out from the raw water storage tank 21 in an amount equal to the amount of water to be supplied to the consumer, and the amount of treated water stored in the pump 34 is maintained. As a result, an appropriate amount of treated water is always stored in the treated water storage tank 31.

[0089] Even when purification is performed according to water usage, chlorine is not added each time. If chlorine is added to the treated water storage tank 31 every time purification is performed, the amount of chlorine in the circulation system will gradually increase, which may cause corrosion of the piping and equipment and may lead to the generation of chlorine by-products.

[0090] <Basic computer hardware configuration> 8 is a block diagram showing the basic hardware configuration of a computer 90. The computer 90 includes at least a processor 91, a main storage device 92, an auxiliary storage device 93, and a communication IF (interface) 99. These are electrically connected to each other via a bus.

[0091] The processor 91 is hardware for executing an instruction set described in a program, and is composed of an arithmetic unit, a register, a peripheral circuit, and the like.

[0092] The main storage device 92 is for temporarily storing programs, data to be processed by the programs, etc. For example, it is a volatile memory such as a DRAM (Dynamic Random Access Memory).

[0093] The auxiliary storage device 93 is a storage device for saving data and programs, such as a flash memory, a hard disk drive (HDD), a magneto-optical disk, a CD-ROM, a DVD-ROM, or a semiconductor memory.

[0094] The communication IF 99 is an interface for inputting and outputting signals for communicating with other computers via a network using a wired or wireless communication standard. The network is composed of the Internet, a LAN, various mobile communication systems constructed by wireless base stations, etc. For example, the network includes 3G, 4G, 5G mobile communication systems, LTE (Long Term Evolution), wireless networks that can connect to the Internet via a specified access point (e.g., Wi-Fi (registered trademark)), etc. In the case of wireless connection, communication protocols include, for example, Z-Wave (registered trademark), ZigBee (registered trademark), Bluetooth (registered trademark), etc. In the case of wired connection, the network also includes a network that is directly connected by a USB (Universal Serial Bus) cable or the like.

[0095] It should be noted that the computer 90 can be virtually realized by distributing all or part of each hardware configuration among multiple computers 90 and connecting them together via a network. In this way, the computer 90 is a concept that includes not only a computer 90 housed in a single housing or case, but also a virtualized computer system.

[0096] <Basic functional configuration of computer 90> A description will now be given of the functional configuration of a computer realized by the basic hardware configuration of a computer 90 shown in Fig. 8. The computer includes at least the functional units of a control unit, a storage unit, and a communication unit.

[0097] The functional units of the computer 90 can also be realized by distributing all or part of the functional units among multiple computers 90 connected to each other via a network. The computer 90 is a concept that includes not only a single computer 90 but also a virtualized computer system.

[0098] The control unit is realized by the processor 91 reading out various programs stored in the auxiliary storage device 93, expanding the programs in the main storage device 92, and executing processes according to the programs. The control unit can realize functional units that perform various information processing depending on the type of program. In this way, the computer is realized as an information processing device that performs information processing.

[0099] The storage unit is realized by a main storage device 92 and an auxiliary storage device 93. The storage unit stores data, various programs, and various databases. Furthermore, the processor 91 can secure a storage area corresponding to the storage unit in the main storage device 92 or the auxiliary storage device 93 in accordance with a program. Furthermore, the control unit can cause the processor 91 to execute processes of adding, updating, and deleting data stored in the storage unit in accordance with the various programs.

[0100] A database refers to a relational database, which is used to manage data sets called tables, which are structured according to rows and columns, by relating them to each other. In a database, a table is called a table, a column in a table is called a column, and a row in a table is called a record. In a relational database, it is possible to set relationships between tables and associate them. Usually, a column is set in each table as a key for uniquely identifying a record, but setting a key in the column is not essential. The control unit can cause the processor 91 to add, delete, or update records in a specific table stored in the storage unit according to various programs.

[0101] The communication unit is realized by the communication IF 99. The communication unit realizes a function of communicating with other computers 90 via a network. The communication unit can receive information transmitted from other computers 90 and input the information to the control unit. The control unit can cause the processor 91 to execute information processing on the received information in accordance with various programs. In addition, the communication unit can transmit information output from the control unit to other computers 90.

[0102] Although several embodiments of the present disclosure have been described above, these embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and modifications are within the scope of the invention and its equivalents as described in the claims, as well as the scope and spirit of the invention.

[0103] <Additional Notes> The matters described in the above embodiments will be supplemented below.

[0104] (Appendix 1) A water treatment system comprising: a raw water storage tank for storing raw water; a first water supply means for supplying the raw water stored in the raw water storage tank; a reverse osmosis membrane for separating the supplied raw water into permeated water and concentrated water; an activated carbon filter for filtering the permeated water; and a treated water storage tank for adding chlorine to the water that has passed through the activated carbon filter and storing the water. (Appendix 2) A water treatment system as described in Appendix 1, further comprising a second water conveying means for conveying the water stored in the treated water storage tank to the raw water storage tank when the chlorine concentration of the water stored in the treated water storage tank does not reach a predetermined concentration. (Appendix 3) The water stored in the treated water storage tank is used for washing, cooking, bathing, showering, or drinking (appendix 1). (Appendix 4) The concentrated water is used as toilet flushing water, water for irrigation, water for landscaping, or emergency water (Appendix 1). (Appendix 5) A water treatment system according to claim 2, wherein, of the water conveyed from the treated water storage tank to the raw water storage tank, surplus water that cannot be stored in the raw water storage tank is used outdoors. (Appendix 6) The reverse osmosis membrane allows the separated permeate to pass through a number of times depending on the use of the water (Appendix 1). (Appendix 7) A method in which raw water stored in a raw water storage tank is pumped by a first water pumping means, the pumped raw water is separated into permeated water and concentrated water by a reverse osmosis membrane, the permeated water is filtered by an activated carbon filter, chlorine is added to the water that has passed through the activated carbon filter, and the water is stored in a treated water storage tank. (Appendix 8) A method as described in Appendix 7, in which, when the chlorine concentration of the water stored in the treated water storage tank does not reach a predetermined concentration, the second water supply means is controlled to supply the water stored in the treated water storage tank to the raw water storage tank. [Explanation of symbols]

[0105] 1. System 100…Buildings 10...Membrane treatment module 11...Conductivity sensor 12...Pressure sensor 13…First filter 15…Sensor group 16...Permeable membrane 17...Sensor group 18…Activated carbon filter 19…Valve 110…Drainage water tank 21…Raw water storage tank 22…Ozone generator 23…Pump 24…Pump 31…Treated water storage tank 33…Chlorine supply section 34…Pump 35...UV sterilization section 36...Control device 37…Sensor

Claims

1. a raw water storage tank for storing raw water; a first water conveying means for conveying raw water stored in the raw water storage tank; a reverse osmosis membrane that separates the delivered raw water into permeate and concentrated water; a sensor for sensing the permeated water; means for stopping all operations when the sensed value satisfies a predetermined condition; A water treatment system comprising:

2. A water treatment system as described in claim 1, wherein the sensor measures the chlorine concentration in a treated water storage tank that stores the permeate water.

3. A group of sensors for sensing the permeated water separated by the reverse osmosis membrane; means for storing data sensed by the group of sensors when all of the operations are stopped; The water treatment system of claim 1 , comprising:

4. A group of sensors that sense the raw water sent to the reverse osmosis membrane; means for storing data sensed by the group of sensors when all of the operations are stopped; The water treatment system of claim 3 .

5. The raw water stored in the raw water storage tank is conveyed by a first water conveying means; The raw water is separated into permeate and concentrated water by a reverse osmosis membrane, Sensing the permeated water with a sensor; A method of stopping all operations when the sensed value satisfies a predetermined condition.

6. A method as described in claim 5, wherein the sensor measures the chlorine concentration in a treated water storage tank that stores the permeate water.

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