JP5019422B2 - Domestic water supply method and apparatus - Google Patents

Description

  The present invention relates to a domestic water supply method and apparatus for processing raw water such as tap water and supplying at least raw water, alkaline water, acidic water and pure water as domestic water.

  With the recent health boom or improvement in living standards, soft water, pure water, acidic water, or alkaline water is actively used as domestic water in addition to tap water. In particular, pure water is suitable for use in washing, dishwashing, cooking, and the like, and there is a demand for a system that can supply abundantly. Alkaline water is attracting attention as drinking water for health, and acidic water is suitably used for sterilization of toilets and foodstuffs.

  Japanese Patent Application Laid-Open No. 9-151503 has a purifying unit that purifies tap water and a water quality adjusting unit that adjusts the quality of the purified water according to the purpose of use. A supply purification system is disclosed. According to this purification system, it is possible to supply tap water with a water quality adjusted to the purpose of use to an appropriate place.

Japanese Patent Application Laid-Open No. 2002-143854 discloses a first electrode and a second electrode that are provided opposite to each other in an electrolytic cell and are capable of electrochemically treating raw water, a positive potential on the first electrode, In order to form a plurality of cells between the power supply unit for applying a negative potential to the second electrode and between the first electrode and the second electrode, there is an interval between the first electrode and the second electrode. A plurality of ion exchange membranes arranged in a predetermined order, an introduction path that is provided with a flow rate adjustment valve and can pass water to each of the plurality of cells, and a discharge path that discharges treated water from each of the plurality of cells A plurality of ion exchange membranes comprising a monovalent anion selective anion exchange membrane, a non-ion selective anion exchange membrane, a non-ion selective cation exchange membrane, Consists of monovalent cation selective cation exchange membranes It is, and electrochemical water treatment device are arranged in this order between the said first electrode to said second electrode is disclosed. According to this electrochemical water treatment apparatus, deionized water, Na-type soft water, mineral water rich in divalent ions, alkaline water, acidic water and various types of water can be easily generated with one apparatus.
JP-A-9-151503 (Claim 1) JP 2002-143854 A (Claim 1, FIG. 1)

  However, the purification system disclosed in Japanese Patent Application Laid-Open No. 9-151503 has various means such as foreign matter removing means, odor removing means, harmful substance removing means, suitable temperature adjusting means, ion removing means, mineral adding means, pH adjusting means, and gas adding means. There is a problem that the installation cost increases and the piping becomes complicated.

  In addition, the electrochemical water treatment apparatus disclosed in JP-A-2002-143854 can easily obtain pure water, acidic water and alkaline water, but uses tap water as raw water and operates at a high voltage because of the large distance between the electrodes. There is a need. In addition, the structure of the apparatus is complicated, and ion exchange membranes are frequently used, which is expensive.

  Accordingly, an object of the present invention is to provide a domestic water supply apparatus that can obtain alkaline water, acidic water, and pure water, and that has a relatively simple living water supply method and apparatus structure that can make the electrolytic cell compact. is there.

  Under such circumstances, the present inventor has conducted intensive studies, and as a result, processed raw water with a reverse osmosis membrane device to obtain concentrated water and permeated water, and flowed the concentrated water obtained from the reverse osmosis membrane device into an electrolytic cell. A step of obtaining alkaline water from the cathode chamber and acidic water from the anode chamber, and supplying raw water, permeated water, alkaline water and acidic water to the point of use as domestic water, alkaline water, The present inventors have found that acid water and pure water can be obtained and that the electrolytic cell can be made compact, and that an expensive ion exchange membrane is not used, so that it can be manufactured at low cost, and the present invention has been completed.

That is, the present invention (1) includes a desalting step of treating raw water with a reverse osmosis membrane device to obtain concentrated water and permeated water, and flowing the concentrated water obtained from the reverse osmosis membrane device into an electrolytic cell, And alkaline water obtained from the cathode chamber, using raw water as the raw water use point, permeate water as the permeate use point, and an electrolysis step for obtaining acidic water from the anode chamber and acidic water from the anode chamber . An object of the present invention is to provide a domestic water supply method characterized by supplying acidic water obtained from the anode chamber to an acidic water use point at an alkaline water use point at which alkaline water is used for cleaning foods .

The present invention is also a domestic water supply device comprising a reverse osmosis membrane device and an electrolytic cell for electrolyzing the supplied treated water to produce alkaline water and acidic water, wherein the reverse osmosis membrane device A raw water introduction pipe is arranged on the raw water side, a concentrated water outflow pipe is arranged on the concentrated water side, a permeate outflow pipe is arranged on the permeate side, and the reverse osmosis membrane device is arranged on the treated water inflow side of the electrolytic cell. Concentrated water outflow piping, alkaline water outflow piping in the cathode chamber, acidic water outflow piping in the anode chamber, raw water supply piping connecting the raw water introduction piping and raw water use point, permeate outflow piping, Permeated water supply pipe connecting the permeated water use point, alkaline water outflow pipe and alkaline water supply pipe connecting alkaline water use point where alkaline water is used for washing food , acidic water outflow pipe and acidic water use point Connect the acidic water supply pipe, There is provided a domestic water supply system for carrying out the domestic water supply method of the present invention (1), characterized in that the respective distribution.

  According to the domestic water supply method of the present invention, alkaline water, acidic water and pure water can be obtained, and the electrolytic cell can be made compact. Moreover, according to the domestic water supply apparatus of this invention, since an expensive ion exchange membrane is not used, it can manufacture at low cost.

  In the domestic water supply method and apparatus of the present invention (hereinafter, two inventions are simply referred to as “in the present invention”), the raw water is water such as tap water used as domestic water. Tap water usually contains divalent cations such as calcium ion and magnesium ion, strong electrolyte such as sodium ion, potassium ion, chloride ion, nitrate ion and sulfate ion, weak electrolyte such as carbonate ion and silica, etc. Impurities are included in various ratios.

  In the present invention, the water for daily use is various types of water that is necessary for a human being used in a dining room, a washroom, a bathroom, etc. to live a life, and includes drinking water. For this reason, people living in water such as single-family houses, apartment houses, and temporary houses, as well as company offices, factories, laboratories, research laboratories, hospitals, and lodging facilities are active. The place to do is also included.

  Next, a domestic water supply method and a domestic water supply apparatus according to an embodiment of the present invention will be described with reference to FIG. The domestic water supply device 50 of this example includes a reverse osmosis membrane device 10 and an electrolytic cell 20 that electrolyzes the supplied water to be treated to generate alkaline water and acidic water. The apparatus 10 is provided with a raw water introduction pipe a on the raw water side, a concentrated water outflow pipe c on the concentrated water side, and a permeate outflow pipe b on the permeate side. Has a concentrated water outlet pipe c of the reverse osmosis membrane device 10, an alkaline water outlet pipe d in the cathode chamber, and an acidic water outlet pipe e in the anode chamber, and connects the raw water introduction pipe a and the raw water use point. Raw water supply pipe A, permeated water outflow pipe b, permeated water supply pipe B connecting permeate use point, alkaline water outflow pipe d, alkaline water supply pipe D connecting alkaline water use point, and acidic water outflow pipe e. Acidic water supply pipe E connecting the acidic water use point, It is intended to distribution, respectively.

  The reverse osmosis membrane device (RO) 10 is not particularly limited, and a known reverse osmosis membrane device can be used. Various types of RO membranes can be used, from high pressure membranes of 3.9 MPa or higher to ultralow pressure membranes of 0.98 MPa or lower. Further, as the RO membrane, a membrane of cellulose acetate and its derivatives or a synthetic polymer membrane can be used. The reverse osmosis membrane device is usually used as a device (module) in which the membrane is housed in a type that can be industrially used. Examples of the module form include a hollow fiber type, a spiral type, a flat plate type, a tube type, and a hollow fiber type.

The electrolyzer 20 is not particularly limited as long as it supplies electrolyzed supplied water to produce alkaline water and acidic water, and a known electrolyzer can be used. The electrolytic cell 20 has, for example, a pair of titanium substrates connected to a direct current power source and electrodes that are plated with platinum facing each other as an anode and a cathode, and a space formed between the electrodes serves as an electrolysis chamber. A treated water introduction pipe, an acidic water discharge pipe connected to the anode side, and an alkaline water discharge pipe installed on the cathode side, while passing the treated water into the electrolysis chamber, the current density between the electrodes was 0 An example is one in which a current of about 1 to 10 A / dm ² is applied to discharge acidic water from the vicinity of the anode and alkaline water from the vicinity of the cathode. A diaphragm type electrolytic cell may be used in which a porous film such as polyethylene, polypropylene, or ceramic is disposed in the electrolysis chamber, and the electrolysis chamber is divided into an anode chamber on the anode side and a cathode chamber on the cathode side. Further, in these electrolytic cells, it is also possible to use a multi-tank electrolytic cell in which a plurality of sets of anodes and cathodes are arranged and a direct current is passed in parallel or in series with these electrodes. Further, in order to prevent calcium ions and magnesium ion salts and hydroxides from depositing on the cathode, the polarity of the anode and the cathode is periodically reversed at intervals of about 20 minutes to 1 hour during energization, and It may be an electrolytic cell provided with a polarity reversing mechanism that switches between acid water and alkaline water discharge pipes in synchronization with reversal.

  Next, a method for supplying domestic water using the domestic water supply apparatus 50 of this example will be described. In order to produce domestic water using the domestic water supply device 50, the raw water is processed by the reverse osmosis membrane device 10 to obtain concentrated water and permeate, and the electrolytic cell 20 is obtained from the reverse osmosis membrane device 10. The step of supplying concentrated water and supplying alkaline water from the cathode chamber and acidic water from the anode chamber, and supplying raw water, permeated water, alkaline water and acidic water to the point of use as domestic water.

  The RO permeated water obtained in step I is supplied to the point of use as pure water after removing impurity ions and the like in the raw water. Pure water is suitable for washing, dishwashing and cooking. In the RO concentrated water obtained in the step I, impurities in the raw water are concentrated. For example, when the RO recovery rate is 65%, the ion concentration in the RO concentrated water is nearly three times the ion concentration in the raw water. The RO concentrated water is sent to the electrolytic cell 20.

  In step II, RO concentrated water is passed through the concentrated water outflow pipe c into the electrolytic cell 20, and a DC potential is applied to the cathode and the anode. When water is passed through the electrolyzer 20 and energized, the anode outlet water discharged from the anode water outflow pipe e contains oxygen and hypochlorous acid and has an oxidizing power and a sterilizing power because oxygen gas is generated by the anode reaction. Therefore, it can be used as acidic water. Further, the cathode outlet water discharged from the cathode water outflow pipe h can be used as alkaline water having reducibility because hydrogen gas is generated by the cathode reaction.

  In the present invention, RO concentrated water having a high ion concentration is used as the water to be treated in the electrolytic cell 20, so that it can be operated at a low voltage. Further, when raw water is used as the water to be treated in the electrolytic cell 20 instead of RO concentrated water, for example, the apparatus must be large in order to obtain alkaline water or acidic water having the same pH. Since the domestic water supply device normally has a limited installation volume, it is a great advantage that the device can be made compact.

  The alkaline water obtained in step II is suitably used for cooking and cleaning foods. Alkaline water obtained by electrolyzing RO concentrated water has a high vegetable washing effect, although the reason is unknown, compared with alkaline water having the same pH value obtained by electrolyzing raw water. Acidic water is suitably used for toilets and food sterilization. Moreover, raw water can be used as domestic water as before, and can also be used as emergency water when pure water, alkaline water and acidic water cannot be collected. Specifically, the raw water supply pipe A is preferably separately piped so that it can be supplied to all domestic water use points.

  Next, a domestic water supply method and a domestic water supply apparatus according to another embodiment of the present invention will be described with reference to FIG. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, description thereof will be omitted, and different points will be mainly described. That is, FIG. 2 is different from FIG. 1 in that the acidic water storage tank 21 and the acidic water supply pump 24 are arranged in the middle of the alkaline water supply pipe D in the middle of the acidic water supply pipe E from the upstream side toward the downstream side. Are provided with an alkaline water storage tank 22 and an alkaline water supply pump 25, and a permeated water storage tank 23 and a permeated water supply pump 26 in the middle of the permeated water supply pipe B, respectively. And the acidic water storage tank 21 are connected by the acidic water return pipe 27, the alkaline water supply pipe downstream of the alkaline water storage tank 22 and the alkaline water storage tank 22 are connected by the alkaline water return pipe 28, and the permeated water storage tank 23 is connected. The permeated water supply pipe 50 and the permeated water storage tank 23 are connected to each other by a permeated water return pipe 29.

  That is, the acidic water, alkaline water and permeated water obtained in each step flow into the respective storage tanks, and are supplied from the storage tanks to the point of use by the respective supply pumps and used at the point of use. Supply water in excess of the amount to be returned is returned to the reservoir. For this reason, each domestic water can be stably supplied to a use point. Further, in each of the storage tanks 21 to 23, convenience is provided by adding a means for automatically stopping the apparatus by detecting a high water level and a means for automatically operating the apparatus by detecting a low water level. Increased further.

  In the present invention, the reverse osmosis membrane device 10 is provided with a pretreatment device for removing organic components such as residual chlorine and trihalomethane from the raw water, and fine particles such as iron oxide and silica, from the raw water. It is preferable in that the film surface can be prevented. Specific examples of the pretreatment device include activated carbon and a membrane separation device.

  If domestic water is manufactured using the domestic water supply devices 50 and 50a of this example, alkaline water, acidic water and pure water can be obtained, and the electrolytic cell can be made compact.

  In the present invention, it is preferable that the alkaline water storage tank 22 and the permeated water storage tank 23 are provided with a sterilization facility from the viewpoint of preventing decay of alkaline water and permeated water in the storage tank by microorganisms. Examples of the sterilization facility include an ultraviolet irradiation method or a method of installing a filter with silver in a storage tank and a storage tank outlet pipe.

  In the present invention, the reverse osmosis membrane device 10 may be a multistage of a front stage and a rear stage. That is, recovery of RO permeated water (pure water) can be enhanced by using the concentrated water obtained from the upstream reverse osmosis membrane device as the treated water of the downstream reverse osmosis membrane device. Moreover, when installing a pressure | voltage rise pump in the front | former stage of a reverse osmosis membrane, collection | recovery of RO permeated water (pure water) can be improved also by circulating a part of concentrated water upstream of this pump.

  Next, the present invention will be described more specifically with reference to examples. However, this is merely an example and does not limit the present invention.

  In accordance with the flow chart of the domestic water supply device shown in FIG. 2, 1280 L / day of tap water is supplied to the reverse osmosis membrane device, RO concentrated water is supplied to the electrolytic cell, and the acid water is treated under the following operating conditions. Alkaline water and permeated water were obtained. As a result, 390 L / day of acidic water, alkaline water; 52 L / day, and 838 L / day of RO permeated water (pure water) were obtained. In addition, the tap water used what passed the activated carbon + microfiltration filter (D-4 form + FU cartridge, the organo company make).

<Reverse osmosis membrane device>
・ RO membrane module (RE2012-LP x 3; manufactured by Sehan)
・ Tap water supply amount: 1280 L / day ・ RO concentrated water amount: 442 L / day, RO permeate water amount: 838 L / day ・ RO recovery rate: 65%

<Electrolytic cell>
・ Electrolysis device (double tank type with diaphragm; manufactured by Organo)
・ Conducting current value: 0.8A
・ Average applied voltage: 4.0V
・ Water to be treated; RO concentrated water volume: 442 L / day ・ Acidic water volume: 390 L / day ・ Alkaline water volume: 52 L / day

<Reservoir>
・ Capacity of acidic water storage tank and alkaline water storage tank; 50L each
・ Capacity of permeate storage tank: 150L

It is a flowchart of the domestic water supply apparatus in this Embodiment. It is a flowchart of the domestic water supply apparatus in other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reverse osmosis membrane apparatus ae, A, B, D, E Piping 20 Electrolysis tank 21 Acidic water storage tank 22 Alkaline water storage tank 23 Permeated water storage tank 24-26 Pump 27-29 Return piping 50, 50a Water supply for domestic use apparatus

Claims (5)

A desalination step in which raw water is treated with a reverse osmosis membrane device to obtain concentrated water and permeated water, and concentrated water obtained from the reverse osmosis membrane device is flowed into an electrolytic cell, and alkaline water from the cathode chamber and acidic water from the anode chamber An electrolysis step for obtaining water, and as raw water for daily use, raw water is used as a raw water use point, permeate is used as a permeate use point, alkaline water obtained from the cathode chamber is used for washing foods A water supply method for domestic use, characterized in that acidic water obtained from the anode chamber is supplied to the acidic water usage point at the alkaline water usage point.   The permeated water obtained in the desalting step and the alkaline water and acidic water obtained in the electrolysis step flow into the respective storage tanks and are supplied from the storage tanks to the point of use. The domestic water supply method according to claim 1, wherein supply water exceeding the amount used is returned to the storage tank. A reverse osmosis membrane device;
A water supply device for daily life comprising an electrolyzer that electrolyzes the supplied treated water to produce alkaline water and acidic water,
The reverse osmosis membrane device is provided with a raw water introduction pipe on the raw water side, a concentrated water outflow pipe on the concentrated water side, and a permeate outflow pipe on the permeate side,
Concentrated water outflow piping of the reverse osmosis membrane device is arranged on the treated water inflow side of the electrolytic cell, alkaline water outflow piping is arranged in the cathode chamber, and acidic water outflow piping is arranged in the anode chamber, respectively.
A raw water supply pipe connecting the raw water introduction pipe and the raw water use point;
A permeate supply pipe connecting the permeate outflow pipe and the permeate use point;
An alkaline water supply pipe for connecting an alkaline water outlet pipe and an alkaline water use point where alkaline water is used for cleaning foods ;
3. The water supply method for domestic use according to claim 1, wherein an acid water outflow pipe and an acid water supply pipe connecting the acid water use point are respectively arranged. Domestic water supply device.   A permeated water storage tank is provided in the middle of the permeated water supply pipe, an alkaline water storage tank is provided in the middle of the alkaline water supply pipe, and an acidic water storage tank is provided in the middle of the acidic water supply pipe. A downstream permeate water supply pipe and the permeate water storage tank are connected by a permeate return pipe, an alkaline water supply pipe downstream of the alkaline water storage tank and the alkaline water storage tank are connected by an alkaline water return pipe, The domestic water supply apparatus according to claim 3, wherein the acidic water supply pipe on the downstream side of the acidic water storage tank and the acidic water storage tank are connected by an acidic water return pipe.   The water supply device for domestic use according to claim 3 or 4, wherein a pretreatment device for removing organic components from the raw water is installed in a front stage of the reverse osmosis membrane device.

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