JP7571973B2 - Water treatment system containing water and valve control method therefor - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act (1) Announced in the introduction of the container package ceramic membrane filtration equipment leasing method published by Metawater Co., Ltd. on July 1, 2020. (2) Announced at https://www.metawater.co.jp/news/2020/09/post-84.html on September 2, 2020. (3) Announced in the September 10, 2020 edition of the Nippon Suido Shimbun published by Nippon Suido Shimbun Co., Ltd. on September 10, 2020. (4) Announced on page 10 of the September 16, 2020 edition of the Chemical Daily published by Chemical Daily Co., Ltd. on September 16, 2020. (5) Announced on page 12 of the October 5, 2020 edition of the Suido Sangyo Shimbun published by Suido Sangyo Shimbun Co., Ltd. on October 5, 2020. (6) Announced on November 25, 2020 at https://www.metawater.co.jp/news/2020/11/-biz-2020online.html. (7) Announced at the lecture, Climate Change and Disaster Prevention Biz Online 2020, on November 26, 2020. (8) Announced in the Environmental Newspaper, published by Environmental Newspaper Co., Ltd. on January 1, 2021.

The present invention relates to a contained water treatment system and a valve control method in a contained water treatment system.

For example, water purification plants use water purification equipment that removes suspended solids (SS) contained in raw water (hereinafter simply referred to as raw water) such as river water or well water. Specifically, such water purification equipment mixes a coagulant into the raw water to coagulate the suspended solids contained in the raw water, causing them to precipitate and be removed by filtration. This makes it possible to produce safe water for daily use from the raw water at water purification plants (see Patent Document 1).

JP 2008-296079 A

However, the construction of such water purification plants generally requires a large amount of cost and a large amount of space. Therefore, due to economic reasons and restrictions on construction sites, it may not be possible to build water purification plants even in areas where a supply of water for daily use is necessary.

In addition, for example, in the event of a disaster such as an earthquake, the operation of the water purification plant itself may be halted. Therefore, if only the water purification equipment installed at the water purification plant is used, the supply of domestic water to each consumer's home may be halted. In other words, there is a need to provide a method for easily and stably supplying domestic water.

To achieve the above object, the contained water treatment system of the present invention comprises a transportable container and a water treatment system contained in the container, the water treatment system comprising a mixer that supplies mixed water obtained by mixing the water to be treated with a coagulant, and a filtration device that filters the mixed water supplied from the mixer.

The contained water treatment system of the present invention makes it possible to easily and stably supply water for daily use.

FIG. 1 is a diagram illustrating a configuration example of a contained water treatment system 100 according to the first embodiment. FIG. 2 is a graph illustrating a method for determining the amount of coagulant to be injected into the mixer 1. FIG. 3 is a diagram illustrating a configuration example of a contained water treatment system 200 according to the second embodiment. FIG. 4 is a diagram illustrating a configuration example of a contained water treatment system 300 according to the third embodiment. FIG. 5 is a diagram for explaining a method for adjusting the supply amount of raw water by the valve V4. FIG. 6 is a diagram for explaining a method for adjusting the supply amount of raw water by the valve V4. FIG. 7 is a diagram for explaining a method for adjusting the supply amount of raw water by the valve V4. FIG. 8 is a diagram for explaining a method for adjusting the supply amount of raw water by the valve V4.

Below, an embodiment of the present invention will be described with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention.

[Housing-type water treatment system 100 according to the first embodiment]
First, a storage type water treatment system 100 according to a first embodiment will be described.

Figure 1 is a diagram illustrating an example of the configuration of a contained water treatment system 100 in the first embodiment.

As shown in FIG. 1, the contained water treatment system 100 has, for example, a container 10 and a water treatment system 20 contained in the container 10.

The container 10 is, for example, a portable container. That is, the container 10 is a container that can be transported by being loaded onto a truck or the like. Note that the container 10 may be directly provided with a means of transportation, for example, a vehicle.

The water treatment system 20 includes, for example, a mixer 1 that mixes raw water and a coagulant supplied from outside the container 10 to generate mixed water, and a filtration device 2 that filters the mixed water generated by the mixer 1. Hereinafter, the raw water and the mixed water are collectively referred to as the water to be treated. The water treatment system 20 also includes a storage tank 3 that stores a coagulant. The coagulant stored in the storage tank 3 is supplied to the mixer 1 via valves V1 and V2 by, for example, a pump P. That is, the amount of coagulant supplied to the mixer 1 is adjusted by, for example, the pump P. The valve V1 is a valve that is opened and closed when maintenance is performed on the mixer 1, the filtration device 2, etc., and the valve V2 is a valve that is opened and closed for the purpose of stabilizing the supply of coagulant to the mixer 1.

The mixer 1 is, for example, an in-line mixer that injects and mixes the coagulant supplied from the storage tank 3 via line L3 into the raw water supplied from outside the container 10 via line L1. The mixer 1 then supplies the resulting mixed water to the filtration device 2 via line L2. The coagulant may be supplied in line L1 and mixed with the raw water, or may be supplied directly to the mixer 1 and mixed with the raw water.

The filtration device 2 has, for example, a filtration membrane 2a that filters the mixed water supplied from the mixer 1 via the line L2. Specifically, the filtration device 2 has, for example, a plurality of filtration membranes 2a that filter the mixed water in parallel. The filtration membranes 2a are, for example, ceramic membranes.

The filtration device 2 then supplies the filtered mixed water to the outside of the container 10.

Valve V3 is, for example, a valve provided between mixer 1 and filtration device 2 (line L2) that can adjust the amount of mixed water supplied to filtration device 2.

In other words, unlike typical water purification facilities, the contained water treatment system 100 in the first embodiment purifies raw water without using a mixing tank or the like for mixing a flocculant with the raw water. Specifically, the contained water treatment system 100 mixes the flocculant with the raw water and forms flocs in the mixer 1, or in the mixer 1 and line L2.

As a result, the housed water treatment system 100 can eliminate the space required for purifying raw water, making it possible to achieve a smaller size compared to general water purification equipment. Therefore, the housed water treatment system 100 can be transported, for example, by being loaded onto a truck or the like.

In addition, the contained water treatment system 100 can reduce the number and size of components compared to typical water purification equipment, making it possible to reduce costs compared to typical water purification equipment.

Furthermore, the housed water treatment system 100 can be loaded onto a truck or the like for transport, making it possible to purify raw water at the desired location. Therefore, the housed water treatment system 100 can supply water for daily use even in locations where it is not possible to build a water purification plant due to economic reasons or construction site constraints. Furthermore, the housed water treatment system 100 can supply water for daily use to areas in need, for example, in the event of a disaster.

[Method for determining the amount of coagulant to be injected]
Next, a method for determining the amount of coagulant to be injected into the mixer 1 will be described.

Figure 2 is a graph that explains how to determine the amount of coagulant to be injected into the mixer 1. In the graph shown in Figure 2, the horizontal axis corresponds to the turbidity of the raw water, and the vertical axis corresponds to the amount of coagulant to be injected per unit time.

The amount of coagulant injected into the mixer 1 (the amount of coagulant supplied through valves V1 and V2) is determined, for example, according to the turbidity of the raw water supplied from the outside to the contained water treatment system 100. Specifically, the amount of coagulant injected into the mixer 1 is determined, for example, according to the turbidity of the raw water measured by a turbidimeter (not shown) installed inside or outside the container 10.

More specifically, as shown in FIG. 2, for example, when the turbidity of the raw water is equal to or less than the first turbidity, the operator adjusts the amount of coagulant injected by the pump P so that the amount injected per unit time is constant (first injection amount). Also, for example, when the turbidity of the raw water is equal to or more than the first turbidity and equal to or less than the second turbidity, the operator adjusts the amount of coagulant injected by the pump P so that the amount injected per unit time increases in accordance with the increase in the turbidity of the raw water. Furthermore, for example, when the turbidity of the raw water is equal to or more than the second turbidity, the operator adjusts the amount of coagulant injected by the pump P so that the amount injected per unit time is constant (second injection amount).

In this regard, when the turbidity of the raw water is equal to or greater than the first turbidity and equal to or less than the second turbidity, in the example shown in FIG. 2, adjustments are made so that the increase in the injection amount per unit time for the turbidity of the raw water is constant, but the injection amount per unit time for the turbidity of the raw water may increase at a pace other than constant.

The amount of flocculant to be injected into the mixer 1 may be determined, for example, by a control device (not shown) installed inside or outside the container 10. The control device is, for example, a computer having a CPU (Central Computing Unit) and memory. Specifically, the control device may perform a process to determine the amount of flocculant to be injected into the mixer 1 by using a signal transmitted from, for example, a turbidity meter (not shown).

The opening and closing of valves V1 and V2 may be performed automatically, for example, by a valve opening and closing device (not shown) installed in container 10. Specifically, the valve opening and closing device may open and close valves V1 and V2 so that, for example, an amount of coagulant corresponding to an injection amount indicated by a signal transmitted from the control device is injected into mixer 1.

[Housing-type water treatment system 200 according to the second embodiment]
Next, a storage type water treatment system 200 according to a second embodiment will be described.

Figure 3 is a diagram illustrating an example of the configuration of a contained water treatment system 200 in the second embodiment. Note that only the differences from the contained water treatment system 100 described in the first embodiment will be described below.

In general, in water purification facilities, a coagulant is injected into the raw water to coagulate suspended solids contained in the raw water and form flocs. Then, in the water purification facility, the raw water is purified by settling and removing the formed flocs.

In the water purification equipment described above, the GT value, for example, is used as a criterion for determining whether or not good flocs have been formed. The GT value is a value calculated by multiplying the G value, which indicates the mixing strength between the raw water and the coagulant, by the T value, which indicates the duration of mixing between the raw water and the coagulant.

In this regard, in typical water purification facilities, for example, raw water and coagulant are mixed in a mixing tank, making it possible to ensure a sufficient GT value.

In contrast, the contained water treatment system 100 described in the first embodiment does not have a mixing tank due to the need to achieve compact equipment, so it is not possible to ensure sufficient time for the mixed water to reach the filtration device 2, and it may not be possible to ensure sufficient mixing time (T value) between the raw water and the coagulant. Therefore, in the contained water treatment system 100 in the first embodiment, there are cases in which mixed water without sufficient coagulant mixed therein reaches the filtration device 2, and good flocs may not be formed.

Therefore, in the second embodiment of the contained water treatment system 200, as shown in FIG. 3, a pump P2 in which the change in the amount of coagulant injected per unit time is less than a predetermined value is used as the pump that supplies the coagulant to the mixer 1. Specifically, the pump P2 is, for example, a non-pulsating pump.

That is, for example, if a pump that has a large change in the amount of coagulant injected per unit time (e.g., a pulsating pump) is used as the pump that supplies the coagulant to the mixer 1, there is a possibility that the injection pace of the coagulant to the mixer 1 will be uneven. In this regard, in an environment where the T value can be sufficiently secured, such as a water purification facility having a mixing tank, it is possible to generate good flocs even when the injection pace of the coagulant is uneven. However, in an environment where the T value cannot be sufficiently secured, there is a possibility that good flocs will not be formed before reaching the filtration device 2. For this reason, in the contained water treatment system 200 in the second embodiment, pump P2, which has small unevenness in the injection pace of the coagulant, is used as the pump that supplies the coagulant to the mixer 1.

This allows the contained water treatment system 200 to reduce the residence time required for floc formation. Therefore, even in an environment where the T value cannot be sufficiently secured, the contained water treatment system 200 can reduce the occurrence of cases where mixed water that does not contain sufficient coagulant reaches the filtration device 2, making it possible to form good flocs.

[Housing-type water treatment system 300 according to the third embodiment]
Next, a storage type water treatment system 300 according to a third embodiment will be described.

Figure 4 is a diagram illustrating an example of the configuration of a contained water treatment system 300 in the third embodiment. Note that only the differences from the contained water treatment system 100 described in the first embodiment and the contained water treatment system 200 described in the second embodiment will be described below.

As shown in FIG. 4, the water treatment system 20 has a pressure gauge 4a (hereinafter also referred to as the first pressure gauge 4a) and a pressure gauge 4b (hereinafter also referred to as the second pressure gauge 4b). The water treatment system 20 also has a valve V4 that adjusts the amount of raw water supplied to the mixer 1.

The pressure gauge 4a is installed, for example, between the valve V4 and the mixer 1 (line L1) and measures the flow pressure (pressure) of the raw water supplied to the mixer 1.

The pressure gauge 4b is installed, for example, in the filtration device 2, and measures the flow pressure of the mixed water in the upstream stage of the filtration device 2, or the flow pressure difference (pressure difference) of the mixed water in the upstream stage and the downstream stage of the filtration device 2. In the following, the pressure gauge 4b will be described as a single pressure gauge, but the pressure gauge 4b may be composed of, for example, a pressure gauge that measures the flow pressure of the mixed water in the upstream stage of the filtration device 2, and a pressure gauge that measures the flow pressure of the mixed water in the downstream stage of the filtration device 2.

Valve V4 is a valve that can adjust the amount of raw water supplied based on the flow pressure measured by pressure gauge 4a or pressure gauge 4b, for example. Specifically, the operator adjusts the amount of raw water supplied to mixer 1 by opening and closing valve V4, for example, and adjusts the flow pressure upstream of valve V3.

The amount of raw water supplied by valve V4 may be determined, for example, by a control device (not shown) installed in container 10. Specifically, the control device may perform a process to determine the amount of raw water supplied by valve V4, for example, by using a signal transmitted from pressure gauge 4a or a signal transmitted from pressure gauge 4b.

The valve V4 may be opened and closed automatically, for example, by a valve opening and closing device (not shown) installed in the container 10. Specifically, the valve opening and closing device may open and close the valve V4 so that raw water corresponding to the supply amount indicated by the signal transmitted from the control device is supplied to the mixer 1.

[Method of adjusting the supply amount of raw water by valve V4]
Next, a method for adjusting the amount of raw water supplied by the valve V4 will be described.

Figures 5 to 8 are diagrams explaining how the raw water supply amount is adjusted by valve V4. Note that the following describes a case where the raw water supply amount is adjusted manually by valve V4.

As shown in FIG. 5, for example, when the first confirmation timing occurs, the operator obtains the flow pressure of the mixed water supplied to the valve V3 from the pressure gauge 4a (YES in S11, S12). The first confirmation timing may be, for example, the timing when a predetermined time has elapsed after the supply of the mixed water to the filtration membrane 2a is initially started. The first confirmation timing may also be, for example, the timing when a predetermined time has elapsed after the filtration membrane 2a has been cleaned.

Then, the operator determines whether the flow pressure obtained in the process of S12 is equal to or greater than the first threshold value (S13).

As a result, if it is determined that the flow pressure obtained in the process of S12 is equal to or greater than the first threshold value (YES in S14), the operator reduces the amount of raw water supplied by valve V4 (S15). Specifically, the operator reduces the amount of raw water supplied by, for example, manually closing valve V4.

That is, immediately after the supply of mixed water to the filtration membrane 2a starts or immediately after the filtration membrane 2a is cleaned, as shown in FIG. 6(A), the filtration membrane 2a is not very clogged, so the flow pressure of the mixed water in the upstream stage of the filtration membrane 2a (filter 2) is low. Therefore, in this case, if the flow pressure in the upstream stage of the valve V3 is high, the flow pressure difference between the flow pressure in the upstream stage of the valve V3 and the flow pressure in the downstream stage becomes large, which may cause the valve V3 to malfunction. Specifically, if the flow pressure difference between the flow pressure in the upstream stage of the valve V3 and the flow pressure in the downstream stage is not within a predetermined range, for example, a cavitation phenomenon occurs in the valve V3, increasing the possibility of abnormal noise or malfunction.

As shown in FIG. 6(B), if the flow pressure measured by the pressure gauge 4a is equal to or greater than the first threshold immediately after the start of the supply of mixed water to the filtration membrane 2a or immediately after the filtration membrane 2a is cleaned, the operator determines that there is a high possibility that the flow pressure difference between the flow pressure in the upstream stage and the flow pressure in the downstream stage of the valve V3 is large, and closes the valve V4 to reduce the amount of raw water supplied by the valve V4. That is, in this case, the operator performs control to close the valve V4 so that the flow pressure difference between the flow pressure in the upstream stage and the flow pressure in the downstream stage of the valve V3 is within a predetermined range.

This allows the contained water treatment system 300 to prevent malfunctions and other problems from occurring in the valve V3.

In addition, as described below, the contained water treatment system 300 makes it possible to reduce the amount of mixed water supplied to the filtration device 2 in order to increase the amount of mixed water supplied to the filtration device 2 at the required timing.

Then, as shown in FIG. 7, for example, when the second confirmation timing is reached, the operator obtains the flow pressure difference between the flow pressure of the mixed water supplied to the filter device 2 (the flow pressure in the upstream stage of the filter device 2) and the flow pressure of the mixed water supplied from the filter device 2 (the flow pressure in the downstream stage of the filter device 2) from the pressure gauge 4b (YES in S21, S22). The second confirmation timing may be, for example, the timing when a predetermined time has elapsed after the processing of S14 is performed.

Then, the operator determines whether the flow pressure difference obtained in the process of S22 is equal to or greater than the second threshold value (S23).

As a result, if it is determined that the flow pressure difference obtained in the process of S22 is equal to or greater than the second threshold value (YES in S24), the operator increases the amount of raw water supplied by valve V4 (S25). Specifically, the operator increases the amount of raw water supplied by, for example, manually opening valve V4.

That is, if the supply of mixed water to the filtration membrane 2a continues for a long time, as shown in FIG. 8(A), the clogging of the filtration membrane 2a increases, and the flow pressure of the mixed water in the upstream stage of the filtration device 2 increases. Therefore, for example, if it is necessary to maintain the amount of mixed water filtered in the filtration device 2, it is necessary to increase the flow pressure in the upstream stage of the valve V3 by increasing the amount of mixed water supplied to the filtration device 2 over time.

In this regard, for example, it is possible to increase the amount of mixed water supplied to the filtration device 2 by providing a separate pump for increasing the amount of raw water supplied to the mixer 1. However, if there is insufficient space inside the container 10 in the contained water treatment system 300, it may not be possible to install a pump in the container 10 for increasing the amount of raw water supplied to the mixer 1.

In the present embodiment, in the case where the flow pressure difference measured by the pressure gauge 4b is equal to or greater than the second threshold, it is determined that the filtration membrane 2a is severely clogged, as shown in FIG. 8(B), and the amount of raw water supplied by the valve V4 is increased by opening the valve V4. That is, in this case, the operator performs control to open the valve V4 so that the flow pressure difference between the flow pressure in the upstream stage and the flow pressure in the downstream stage of the valve V3 is within a predetermined range.

As a result, the contained water treatment system 300 is able to increase the amount of mixed water supplied to the filtration device 2 without, for example, providing a separate pump for increasing the amount of raw water supplied to the mixer 1. Therefore, the contained water treatment system 300 is able to maintain the amount of mixed water filtered in the filtration device 2 even if the flow pressure difference in the filtration device 2 increases over time.

Reference Signs List 1: Mixer 2: Filtration device 2a: Filtration membrane 3: Storage tank 4a: Pressure gauge 4b: Pressure gauge 10: Container 20: Water treatment system 100: Housed water treatment system 200: Housed water treatment system 300: Housed water treatment system L1: Line L2: Line L3: Line P1: Pump P2: Pump V1: Valve V2: Valve V3: Valve V4: Valve

Claims (4)

a transportable container;
A water treatment system contained in the container,
The water treatment system comprises:
A mixer that supplies mixed water obtained by mixing the water to be treated and a coagulant;
a pump for injecting the flocculant into the mixer;
a filtration device that filters the mixed water supplied from the mixer,
The pump is a pump in which the change in the injection amount of the coagulant per unit time is equal to or less than a predetermined value, and further
A contained water treatment system comprising a control device that controls the amount of the treated water supplied to the mixer by a second valve that adjusts the amount of the treated water supplied to the mixer in accordance with at least one of the pressure of the treated water supplied to a first valve that adjusts the amount of the mixed water supplied to the filtration device, and the pressure difference between the pressure of the mixed water supplied to the filtration device and the pressure of the mixed water supplied from the filtration device. 10. The contained water treatment system of claim 1 , wherein the pump is a non-pulsating pump. A valve control method for a contained water treatment system, comprising: a transportable container; and a water treatment system contained in the container, the water treatment system comprising: a mixer that supplies mixed water obtained by mixing water to be treated with a coagulant; a pump that injects the coagulant into the mixer; and a filtration device that filters the mixed water supplied from the mixer, the pump being a pump in which the change in the injection amount of the coagulant per unit time is equal to or less than a predetermined value ,
A valve control method for controlling the amount of treated water supplied to the mixer by a second valve that adjusts the amount of treated water supplied to the mixer in accordance with the pressure of the treated water supplied to a first valve that adjusts the amount of mixed water supplied to the filtration device. A valve control method for a contained water treatment system, comprising: a transportable container; and a water treatment system contained in the container, the water treatment system comprising: a mixer that mixes water to be treated with a coagulant and supplies mixed water; a pump that injects the coagulant into the mixer; and a filtration device that filters the mixed water supplied from the mixer , the pump being a pump in which the change in the injection amount of the coagulant per unit time is equal to or less than a predetermined value ,
A valve control method for controlling the amount of treated water supplied to the mixer by a second valve that adjusts the amount of treated water supplied to the mixer in accordance with the pressure difference between the pressure of the mixed water supplied to the filtration device and the pressure of the mixed water supplied from the filtration device.

Images