Water treatment method and water treatment equipment

Abstract

To decolor or disinfect treatment target water without using chlorine.SOLUTION: A water treatment equipment includes a first contact container for accommodation of treatment target water, a first ozone contact mechanism for supplying ozone and bringing treatment target water accommodated in the first contact container into contact therewith, a second contact container for accommodation of treatment target water in the downstream of a flow of treatment target water than the first contact container, and a second ozone contact mechanism for supplying ozone and bringing treatment target water accommodated in the second contact container into contact therewith.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a water treatment method and a water treatment device. [Background technology]

[0002] Patent Document 1 describes a biological treatment method for organic wastewater, in which the organic wastewater is subjected to multi-stage activated sludge treatment in a first biological treatment tank, which converts the BOD in the organic wastewater into bacterial cells through high-load treatment, and a second biological treatment tank, in which the converted bacterial cells coexist with microscopic animals that prey on the bacterial cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-51415 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, treated water that has been biologically treated in a biological treatment tank may be slightly colored (some color may remain). Even if such residual color is not a problem for practical use, it is desirable to thoroughly decolorize the treated water. Furthermore, it is desirable for such treated water to be sufficiently sterilized. For example, while more effective decolorization or sterilization can be achieved by adding more chlorine to the treated water, it is desirable not to use excessive amounts of chlorine.

[0005] An object of the present disclosure is to decolorize or disinfect the water being treated without the use of chlorine. [Means for solving the problem]

[0006] The water treatment device of the technology disclosed herein includes a first contact vessel that contains water to be treated, a first ozone contact mechanism that supplies ozone to the water to be treated contained in the first contact vessel and brings it into contact with the water, a second contact vessel that contains the water to be treated downstream of the first contact vessel in the flow of the water to be treated, and a second ozone contact mechanism that supplies ozone to the water to be treated contained in the second contact vessel and brings it into contact with the water to be treated.

[0007] The water treatment method of the disclosed technology includes a first contact treatment in which ozone is brought into contact with the water to be treated, and a second contact treatment in which ozone is brought into contact with the water to be treated after the first contact treatment. [Effects of the Invention]

[0008] The technology of the present disclosure can decolorize or disinfect the water to be treated without using chlorine. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the overall configuration of a water circulation system equipped with a water treatment device according to a first embodiment of the disclosed technique. [Figure 2] FIG. 2 is a diagram showing the overall configuration of a water circulation system equipped with a water treatment device according to a second embodiment of the disclosed technique. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the first embodiment will be described with reference to the drawings.

[0011] FIG. 1 shows the overall configuration of a water circulation system 12 according to a first embodiment of the technology of the present disclosure. This water circulation system 12 is a system that circulates and purifies wastewater used in a home, for example, so that the wastewater can be reused within the home. Examples of wastewater include toilet flush water (sewage) used at a water usage point 14 in the home, for example, to flush a toilet bowl. This toilet flush water is an example of the water to be treated by the technology of the present disclosure.

[0012] The water circulation system 12 has a wastewater adjustment tank 100, a biological treatment tank 300, and a treated water storage tank 400. Wastewater passes through the wastewater adjustment tank 100, the biological treatment tank 300, and the treated water storage tank 400 in this order, and is then circulated to the water usage point 14.

[0013] The water usage point 14 and the wastewater adjustment tank 100 are connected by a drainage pipe 102. The wastewater generated at the water usage point 14 is sent to the wastewater adjustment tank 100 through the drainage pipe 102.

[0014] Predetermined treatment such as stirring is performed on the wastewater in the wastewater adjustment tank 100. The gas inside the wastewater adjustment tank 100 may be discharged to the outside of the wastewater adjustment tank 100 by driving a fan, for example.

[0015] The wastewater adjustment tank 100 and the biological treatment tank 300 are connected by a drainage pipe 302. The wastewater in the wastewater adjustment tank 100 is sent to the biological treatment tank 300 through the drainage pipe 302 by driving a drainage pump 110.

[0016] The biological treatment tank 300 is provided with, for example, a biological treatment device and a filtration device. The biological treatment device can biologically treat the wastewater. The filtration device can filter the wastewater. Gas within the biological treatment tank 300 can be discharged to the outside of the biological treatment tank 300 by, for example, driving a fan.

[0017] The biological treatment tank 300 and the treated water storage tank 400 are connected by a treated water pipe 402. A treated water pump 406 is provided on the treated water pipe 402. When the treated water pump 406 is driven, wastewater from the biological treatment tank 300 is sent to the treated water storage tank 400.

[0018] The wastewater is also subjected to predetermined treatment in the treated water storage tank 400. The gas inside the treated water storage tank 400 may be discharged to the outside of the treated water storage tank 400 by driving a fan, for example.

[0019] The treated water storage tank 400 and each of the water usage points 14 are connected by a supply pipe 716. A supply pump 724 is provided on the supply pipe 716. The treated water in the treated water storage tank 400 is sent to each of the water usage points 14 through the supply pipe 716 by driving the supply pump 724. In practice, the supply pipe 716 may branch out to each of the water usage points 14.

[0020] A contact tank 500 is disposed inside the treated water storage tank 400. The contact tank 500 is, for example, a cylindrical container with an open top. The water storage capacity of the contact tank 500 is approximately equal to the volume of the contact tank 500 itself. In contrast, the actual water storage capacity of the treated water storage tank 400 is the volume of the treated water storage tank 400 when the contact tank 500 is not disposed in the treated water storage tank 400 minus the volume equivalent to the volume of the contact tank 500. The actual water storage capacity of the treated water storage tank 400 is the amount of treated water that can actually be stored in the treated water storage tank 400. In the first embodiment, the water storage capacity of the contact tank 500 is less than the actual water storage capacity of the treated water storage tank 400.

[0021] The treated water discharged from the treated water pipe 402 flows into the contact tank 500. The treated water overflowing from the contact tank 500 is stored in the treated water storage tank 400. The contact tank 500 is an example of a first contact vessel, and the treated water storage tank 400 is an example of a second contact vessel.

[0022] 1, one contact tank 500 is disposed inside the treated water storage tank 400, but multiple contact tanks 500 may be disposed therein. In this case, for example, the treated water discharged from the treated water piping 402 flows through the multiple contact tanks 500 in order, and the treated water overflowing from the last contact tank 500 can be stored in the treated water storage tank 400 and treated.

[0023] The contact tank 500 is provided with a first ozone contact mechanism 510. The first ozone contact mechanism 510 is a mechanism that supplies ozone generated by an ozone generator into the contact tank 500 through an ozone supply pipe 512 and brings the ozone into contact with the treated water in the contact tank 500. An ozone outlet of the ozone supply pipe 512 is set below a position halfway up from the bottom of the contact tank 500.

[0024] The treated water storage tank 400 is provided with a second ozone contact mechanism 410. The second ozone contact mechanism 410 is a device that supplies ozone generated by an ozone generator into the treated water storage tank 400 through an ozone supply pipe 412, and brings the ozone into contact with the treated water in the treated water storage tank 400. The ozone outlet of the ozone supply pipe 412 is set below a position halfway up from the bottom of the treated water storage tank 400.

[0025] The actual amount of water stored in the treated water storage tank 400 is set appropriately depending on, for example, the amount of water treated per day in the water circulation system 12. The amount of water stored in the contact tank 500 is set appropriately depending on the treatment (at least one of decolorization and sterilization) performed on the treated water in the contact tank 500 and the ozone supply capacity of the first ozone contact mechanism 510.

[0026] In this embodiment, as shown in FIG. 1 , the water storage capacity of the contact tank 500 is smaller than that of the treated water storage tank 400. By reducing the water storage capacity of the contact tank 500 in this manner, the contact opportunity and contact efficiency of the supplied ozone are increased, allowing the ozone to efficiently contact the treated water, thereby enabling effective treatment (at least one of decolorization and sterilization). For example, even if the ozone supply capacity of the ozone generator is low, reducing the capacity of the contact tank 500 makes it possible to easily contact ozone with the treated water without continuously supplying ozone. Furthermore, reducing the capacity of the contact tank 500, for example, eliminates the need for continuous operation of the first ozone contact mechanism 510 and enables intermittent operation. By intermittently operating the first ozone contact mechanism 510, for example, the actual operating time of the first ozone contact mechanism 510 per day is shortened, thereby reducing wear on the components of the first ozone contact mechanism 510 and reducing power consumption.

[0027] The water treatment module 20 includes the contact tank 500, the first ozone contact mechanism 510, the treated water storage tank 400, and the second ozone contact mechanism 410. This water treatment module 20 can be incorporated into other types of water circulation systems and water treatment systems, not just the water circulation system 12 shown in FIG. 1 . In other words, the water treatment module 20 can be considered a modularized water treatment module that can be incorporated into other water circulation systems or water treatment systems. The water treatment module 20 is an example of a water treatment device of the disclosed technology. It can also be considered that the water treatment module 20 corresponds to the water treatment device of the disclosed technology as a water circulation system 12 that includes the wastewater adjustment tank 100 and the piping, valves, pumps, etc. that connect these tanks.

[0028] Next, the operation of this embodiment will be described.

[0029] Wastewater generated at the water usage points 14 passes through the wastewater adjustment tank 100 and is biologically treated in the biological treatment tank 300. The treated water that has been biologically treated in the biological treatment tank 300 is sent to the treated water storage tank 400.

[0030] A contact tank 500 is provided inside the treated water storage tank 400. Treated water that has been biologically treated in the biological treatment tank 300 first flows into the contact tank 500. A first ozone contact mechanism 510 is provided in the contact tank 500. The first ozone contact mechanism 510 brings ozone generated by an ozone generator into contact with the treated water in the contact tank 500. In this way, the treated water is treated with ozone. This ozone treatment is the first contact treatment of the disclosed technology. Since the ozone supplied to the contact tank 500 comes into contact with the treated water without spreading outside the contact tank 500, efficient ozone contact is possible.

[0031] The ozone outlet of the ozone supply pipe 512 is set below half the height from the bottom of the contact tank 500. Therefore, compared to a configuration in which the ozone outlet of the ozone supply pipe 512 is set above half the height from the bottom of the contact tank 500, the distance and time over which ozone comes into contact with the treated water inside the contact tank 500 can be ensured to be longer.

[0032] The contact tank 500 is disposed inside the treated water storage tank 400. A first contact treatment is carried out in the contact tank 500, and the treated water that overflows from the contact tank 500 is stored in the treated water storage tank 400 (strictly speaking, the space between the inner periphery of the treated water storage tank 400 and the outer periphery of the contact tank 500).

[0033] The treated water storage tank 400 is provided with a second ozone contact mechanism 410. The second ozone contact mechanism 410 brings ozone generated by an ozone generator into contact with the treated water in the treated water storage tank 400. This causes the treated water to be ozone-treated. This ozone treatment is the second contact treatment of the disclosed technology.

[0034] The ozone outlet of the ozone supply pipe 412 is set below half the height from the bottom of the treated water storage tank 400. Therefore, compared to a configuration in which the ozone outlet of the ozone supply pipe 412 is set above half the height from the bottom of the treated water storage tank 400, the distance and time over which ozone comes into contact with the treated water in the treated water storage tank 400 can be secured longer.

[0035] The treated water in the treated water storage tank 400 that has been subjected to the two-stage ozone treatment is then sent to each water usage point 14 via the supply pipe 716 by driving the supply pump 724 .

[0036] As described above, in the water treatment method in the water circulation system 12 of this embodiment, the water to be treated is treated by contacting it with ozone in two stages. For example, even if the treated water has a slight color, the color can be lightened by contacting the treated water with ozone in two stages. Therefore, compared to a configuration in which the treated water is treated with chlorine without contacting ozone, and a configuration in which ozone treatment is performed in only one stage and then chlorine treatment, it is possible to lighten the color of the treated water without using chlorine. Furthermore, from the perspective of sterilizing the treated water, compared to a configuration in which ozone treatment is performed in only one stage and then chlorine treatment, it is possible to sterilize the treated water without using chlorine.

[0037] For example, in order to decolorize or sterilize the treated water to the same degree as in the present embodiment, it is conceivable to bring a larger amount of chlorine into contact with the treated water. However, if chlorine remains in the treated water sent from the treated water storage tank 400 to the water usage point 14, a chlorine odor may be emitted when the water is used. There is also a concern that the residual chlorine may easily cause corrosion of the supply pipe 716.

[0038] In contrast, in this embodiment, it is possible to decolorize or sterilize the treated water without using chlorine. Because chlorine is not used, no chlorine odor is generated when the water is used at the water-using point 14. Furthermore, residual chlorine does not cause corrosion of the supply pipe 716. Furthermore, excessive addition of chemical substances can be suppressed.

[0039] Next, a second embodiment will be described. In the second embodiment, the same elements, members, etc. as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed descriptions thereof will be omitted.

[0040] 2, in the water circulation system 22 of the second embodiment, a water treatment module 24 is provided instead of the water treatment module 20 of the first embodiment. The water treatment module 24 has a contact tank 502 instead of the contact tank 500 in the water treatment module 20 of the first embodiment. The water storage capacity of the contact tank 502 is larger than the water storage capacity of the contact tank 500. In the water circulation system 22 of the second embodiment, the actual storage capacity of the treated water storage tank 400 is smaller than the storage capacity of the contact tank 502.

[0041] In the second embodiment, the water treatment module 24 is also an example of the water treatment device of the disclosed technology. It can also be said that the water treatment module 24, the water circulation system 12 including the wastewater adjustment tank 100, and the piping, valves, pumps, etc. connecting these tanks correspond to the water treatment device of the disclosed technology.

[0042] In the water circulation system 22 of the second embodiment configured as described above, similar to the water circulation system 12 of the first embodiment, wastewater generated at the water usage points 14 passes through the wastewater adjustment tank 100 and is biologically treated in the biological treatment tank 300. The treated water that has been biologically treated in the biological treatment tank 300 is sent to the treated water storage tank 400.

[0043] In the water treatment module 24 of the second embodiment, ozone generated by the first ozone contact mechanism 510 contacts the treated water in the contact tank 502 (first contact treatment), thereby decolorizing and sterilizing the water. The treated water that overflows from the contact tank 502 comes into contact with ozone generated by the second ozone contact mechanism 410 in the treated water storage tank 400 (strictly speaking, the space between the inner periphery of the treated water storage tank 400 and the outer periphery of the contact tank 502) (second contact treatment), thereby decolorizing and sterilizing the water. The water treatment device 23 of the second embodiment can also decolorize and sterilize the treated water without using chlorine.

[0044] In this way, both the water treatment module 20 of the first embodiment and the water treatment module 24 of the second embodiment can decolorize and sterilize the treated water without using chlorine. However, the water treatment device of the disclosed technology may perform either decolorization or sterilization of the treated water, rather than both.

[0045] In particular, both the water circulation system 12 of the first embodiment and the water circulation system 22 of the second embodiment purify wastewater used in toilets while circulating it. Therefore, wastewater is generated irregularly, treated in the biological treatment tank 300, and then sent to the treated water storage tank 400 as treated water. In this case, if decolorization and sterilization treatments are not performed in the treated water storage tank 400 (including the contact tank 500 or the contact tank 502), the chromaticity and bacterial count of the treated water will gradually increase. Even if decolorization and sterilization treatments are performed in the treated water storage tank 400, if these treatments are insufficient, the chromaticity and bacterial count of the treated water will increase, for example, every time toilet wastewater is generated. In contrast, in the water treatment modules 20 and 24 of the disclosed technology, the decolorization and sterilization treatments are appropriately performed in the treated water storage tank 400, thereby preventing excessive increases in the chromaticity and bacterial count of the treated water.

[0046] In the water treatment module 20 of the first embodiment, the water storage capacity of the contact tank 500 is smaller than the substantial water storage capacity of the treated water storage tank 400. That is, in the first contact treatment, ozone can be brought into contact with a relatively small amount of treated water stored inside the contact tank 500. For example, from the perspective of relatively enhancing the decolorization effect, in the first embodiment, ozone is brought into contact with a relatively small amount of treated water at a high concentration in the contact tank 500 before the treated water flows into the treated water storage tank 400, thereby achieving a high decolorization effect on the treated water.

[0047] In contrast, in the water treatment module 24 of the second embodiment, the actual water storage capacity of the treated water storage tank 400 is smaller than the water storage capacity of the contact tank 502. That is, in the second contact treatment, ozone can be brought into contact with a relatively small amount of treated water stored inside the treated water storage tank 400. For example, in terms of relatively enhancing the sterilization effect, if ozone is brought into contact near the outlet of the treated water storage tank 400, the treated water can be sent to the water usage point 14 in a short time after sterilization. In the second embodiment, ozone is brought into contact with a relatively small amount of treated water just before the treated water is supplied from the treated water storage tank 400, so that the sterilization effect on the treated water is high.

[0048] The contact tank 500 may be disposed outside the treated water storage tank 400. Even in this configuration, the capacity of the contact tank 500 can be made smaller than the capacity of the treated water storage tank 400. When the contact tank 500 is disposed inside the treated water storage tank 400 as in the above embodiment, no space is required for disposing the contact tank 500, which contributes to the miniaturization of the water treatment module 20. Furthermore, treated water that overflows from the contact tank 500 can be stored in the treated water storage tank 400 without connecting the contact tank 500 and the treated water storage tank 400 with piping or the like.

[0049] In the disclosed technology, the number of stages of the ozone contact treatment is not limited to the above two stages and may be multiple stages. However, since decolorization and sterilization can be reliably achieved by two stages of ozone contact treatment, from the viewpoint of simplifying the structure of the water treatment module 20 and simplifying the water treatment method, two stages of the ozone contact treatment is preferable.

[0050] In the disclosed technology, the configuration for contacting ozone with treated water is not limited to the configuration shown in FIGS. 1 and 2. For example, ozone may be contacted with treated water (flowing water) at two locations, upstream and downstream, in a pipe through which the treated water flows. In a configuration using a contact tank 500 and a treated water storage tank 400 as shown in FIG. 1, ozone can be efficiently contacted in these tanks, i.e., the first contact vessel and the second contact vessel, while suppressing diffusion of the treated water, and the effect of ozone contact is likely to be highly exerted. Similarly, in a configuration using a contact tank 502 and a treated water storage tank 400 as shown in FIG. 2, ozone can be efficiently contacted in each tank while suppressing diffusion of the treated water, and the effect of ozone contact is likely to be highly exerted.

[0051] In the above, treated water that has been biologically treated in the biological treatment tank 300 is cited as the treated water to be subjected to two-stage ozone contact treatment. However, the treated water to be subjected to two-stage ozone contact treatment is not limited to treated water that has been biologically treated in this manner. In addition, although the above description uses wastewater used in toilets as an example, the raw water (water to be treated) is not limited to this.

[0052] Furthermore, the following notes are disclosed: (Appendix 1) a first contact vessel containing water to be treated; a first ozone contact mechanism that supplies ozone to the treatment target water contained in the first contact vessel and contacts the water with ozone; a second contactor vessel that accommodates the water to be treated downstream of the first contactor vessel in the flow of the water to be treated; a second ozone contact mechanism that supplies ozone to the treatment-target water contained in the second contact vessel and contacts the water with ozone; A water treatment device comprising: (Appendix 2) 2. The water treatment device of claim 1, wherein the first contactor vessel has a smaller capacity than the second contactor vessel. (Appendix 3) 3. The water treatment device of claim 1, wherein the first contactor vessel is disposed inside the second contactor vessel. (Appendix 4) a first contact treatment in which ozone is brought into contact with the water to be treated; a second contact treatment in which ozone is brought into contact with the water to be treated after the first contact treatment; A water treatment method comprising the steps of: (Appendix 5) 5. The water treatment method according to claim 4, wherein the amount of the water to be treated in the second contact treatment is smaller than the amount of the water to be treated in the first contact treatment. [Explanation of symbols]

[0053] 12 Water Circulation System 14 Water usage points 20 Water Treatment Module 22 Water Circulation System 24 Water Treatment Module 100 Drainage adjustment tank 102 Drainage piping 110 Drainage pump 300 Biological treatment tank 302 Drainage piping 400 Treated water storage tank 402 Treated water piping 406 Treated water pump 410 Secondary Ozone Contact Mechanism 412 Ozone supply pipe 500 Contact tank 510 First Ozone Contact Mechanism 512 Ozone supply pipe 716 Supply piping 724 Supply Pump

Claims

1. a first contact vessel containing water to be treated; a first ozone contact mechanism that supplies ozone to the treatment target water contained in the first contact vessel and contacts the water with ozone; a second contactor vessel that accommodates the water to be treated downstream of the first contactor vessel in the flow of the water to be treated; a second ozone contact mechanism that supplies ozone to the treatment-target water contained in the second contact vessel and contacts the water with ozone; A water treatment device comprising:

2. The water treatment device of claim 1 , wherein the first contactor vessel has a smaller volume than the second contactor vessel.

3. The water treatment device of claim 1 , wherein the first contactor vessel is disposed within the second contactor vessel.

4. a first contact treatment in which ozone is brought into contact with the water to be treated; a second contact treatment in which ozone is brought into contact with the water to be treated after the first contact treatment; A water treatment method comprising the steps of:

5. The water treatment method according to claim 4 , wherein the amount of the water to be treated in the second contact treatment is smaller than the amount of the water to be treated in the first contact treatment.

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