JP2014214543A - Sewage/rainwater switching type storage facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewage/rainwater switching type storage facility which can be used as a combined sewage temporary storage facility and also as a rainwater temporary storage facility.SOLUTION: A sewage/rainwater switching type storage facility 100 has a storage tank 20 where a storage content can be switched between sewer in sewerage 14 and rainwater on a site 18 of a building. The storage tank 20 is installed inside the site 18 of the building. The storage tank 20 temporarily stores sewage, returns the same to the sewerage 14 when a sewage flow rate therein is reduced and temporarily stores the rainwater on the site 18 of the building by curbing a sewage receiving amount when precipitation is high.

Description

  The present invention, for example, stores switchable sewage in a combined sewer and rainwater on the building site side so that it can be switched, and is suitable for effectively and economically preventing disasters such as river water quality improvement and flooding of inland water.・ It relates to rainwater switching type storage facilities.

  Conventionally, in a combined sewer, untreated sewage overflowed from a rainwater outlet or the like is discharged into a public water area such as a river when it exceeds a certain flow rate during rainfall, causing water pollution. This phenomenon will be described more specifically with reference to FIG. As shown in FIG. 7, in the combined sewer 1, both sewage and rainwater such as domestic wastewater are sent to the sewage treatment plant 3 through the sewer main line 2 and processed. A part of the sewage overflows from the overflow weir 4a provided in the rain water discharge chamber 4 in the middle of the main line 2, and flows into the river from the rain water discharge port 4b, causing water pollution of the river.

  In order to solve this problem, for example, as shown in Patent Document 1, a separation device is provided in a public sewer manhole to separate sewage into treated water and sewage, or sewage flowing through the public sewer is temporarily In some cases, after being stored in a combined sewage temporary storage facility in public land, it is returned to the sewer when the sewage flow rate decreases. These are generally managed and managed as part of the facilities of sewerage operators. Moreover, in private buildings other than public sewer facilities, as shown in Patent Document 2, for example, sewage from the building is temporarily stored in the site on the building side, leveled, and drained to the public sewer There is.

  On the other hand, the “Rainwater Temporary Storage Facility” that temporarily stores rainwater has been put into practical use for the purpose of effectively using rainwater in the building site, reducing the amount of rainwater inflow into the sewer, and preventing inundation. Some local governments have established guidelines that require the installation of temporary rainwater storage facilities for large-scale redevelopment projects.

JP 2003-80241 A JP 2005-23725 A

  By the way, it is effective to install pollution load reduction equipment in facilities other than sewer companies in order to suppress river water pollution due to overflow water from combined sewers in rainy weather. When both the above rainwater temporary storage facility and the combined sewage temporary storage facility are to be installed on the premises, it is necessary to install multiple storage tanks, which increases the storage capacity. It will swell. For this reason, it has been economically difficult to simultaneously install a rainwater temporary storage facility and a combined sewage temporary storage facility in a private building site.

  This invention is made | formed in view of the above, Comprising: It aims at providing the sewage and rainwater switching type | mold storage facility which can be used as a combined sewage temporary storage facility and a rainwater temporary storage facility.

  In order to solve the above-described problems and achieve the object, a sewage / rainwater switching storage facility according to the present invention has a storage tank that stores switchable sewage in a sewer and rainwater in a building site. A switchable storage facility, wherein the storage tank is provided in a site of the building.

  Further, in the sewage / rainwater switching storage facility according to the present invention, in the above-described invention, the sewer is a combined sewer, and the storage tank is formed from an overflow weir provided in a rainwater discharge chamber of the combined sewer. It is characterized by being able to store overflowed sewage.

  In addition, in the above-described invention, the sewage / rainwater switching storage facility according to the present invention is the above-described invention, wherein the storage tank temporarily stores the sewage, and the stored sewage is reduced when the sewage flow rate of the sewer is reduced. It returns to the said sewer.

  Further, in the sewage / rainwater switching storage facility according to the present invention, in the above-described invention, the storage tank accepts the sewage when the rainfall is small, and accepts the sewage when the rainfall is large. And rain water in the site of the building is temporarily stored.

  In the sewage / rainwater switching type storage facility according to the present invention, the storage tank is capable of storing wastewater in the site of the building other than rainwater in the above-described invention.

  According to the sewage / rainwater switching storage facility according to the present invention, the storage tank has a storage tank that can switchably store the sewage in the sewer and the rainwater in the building site. Is installed in the site of the building, so that a sewage / rainwater switching storage facility that can be used as a combined sewage temporary storage facility or a rainwater temporary storage facility is economically realized in a private building site, for example. There is an effect that can be.

  According to another sewage / rainwater switching type storage facility according to the present invention, the sewer is a combined sewer, and the storage tank receives sewage overflowed from an overflow weir provided in a rainwater discharge chamber of the combined sewer. Since it can be stored, there is an effect that it is possible to prevent water pollution caused by flowing from an overflow weir into a public water area such as a river.

  According to another sewage / rainwater switching type storage facility according to the present invention, the storage tank temporarily stores the sewage, and the stored sewage is returned to the sewer when the sewage flow rate of the sewer decreases. Since it returns, there exists an effect that the possibility of inundation flooding can be reduced.

  Further, according to another sewage / rainwater switching type storage facility according to the present invention, the storage tank receives the sewage when the rainfall is small, and suppresses the amount of the sewage received when the rainfall is large. Since rainwater in the building site is temporarily stored, there is an effect that it is possible to effectively and economically suppress the risk of water pollution and flooding in public water areas such as rivers.

  In addition, according to another sewage / rainwater switching type storage facility according to the present invention, the storage tank can store wastewater in the site of the building other than rainwater, so not only sewage and rainwater are stored, There is an effect that it can also be used as a building drainage temporary storage facility.

FIG. 1 is a schematic block diagram showing an embodiment of a sewer / rainwater switching storage facility according to the present invention. FIG. 2 is an example of the sewer / rainwater switching type storage facility according to the present invention, and is a diagram in the case of storing initial sewage with a high pollution load. FIG. 3 is an example of a sewer / rainwater switching type storage facility according to the present invention, and is a diagram in the case of allowing overflow discharge to a river in the middle of rainfall. FIG. 4 is an example of a sewer / rainwater switching type storage facility according to the present invention, and is a diagram in the case of returning sewage at the time of rain attenuation. FIG. 5 is a diagram illustrating a transition example of a river pollution load at the beginning of rainfall. FIG. 6 is a schematic diagram showing an operation example in the water storage tank of the sewage / rainwater switching type storage facility according to the present invention, where (a) is a diagram at the time of rainfall, and (b) is a diagram at the time of rainfall and at the time of operating the water level sensor. It is. FIG. 7 is a schematic diagram illustrating a situation where water overflowed from a conventional combined sewer flows into a river.

  Embodiments of a sewer / rainwater switching storage facility according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  As shown in FIG. 1, a rainwater discharge chamber 16 is provided in the middle of a sewer main line 14 that guides sewage in the combined sewer 10 to a sewage treatment plant 12. The sewage / rainwater switching type storage facility 100 according to the present invention has a storage tank 20 that stores sewage in the sewer main line 14 and rainwater in the site 18 of the building in a switchable manner. The storage tank 20 is provided by being buried in, for example, the ground in the site 18 of the building.

  Inside the rainwater discharge chamber 16, an overflow weir 22a with a low weir height and an overflow weir 24a with a slightly higher weir height are provided. When the flow rate of sewage flowing through the sewer main line 14 exceeds a predetermined flow rate during rainfall or the like, the overflow water from the overflow weir 22a having a low weir height passes through the rain discharge port 22b and the water conduit 28 as shown in FIG. The storage tank 20 in the site 18 is entered. In this case, the sewage / rainwater switching storage facility 100 of the present invention is used as a combined sewage temporary storage facility.

  On the other hand, as shown in FIG. 3, in the state where the gate valve (not shown) provided on the water conduit 28 is closed, the overflow water from the overflow weir 24a having a high weir height flows from the rainwater outlet 24b to the river as in the conventional case. To be released. In this case, the storage tank 20 can store rainwater in the site 18 of the building, and the sewage / rainwater switching type storage facility 100 of the present invention is used as a temporary rainwater storage facility.

  For this reason, according to the sewage / rainwater switching type storage facility 100 of the present invention, what can be used as a combined sewage temporary storage facility or a rainwater temporary storage facility is realized, for example, in the site 18 of a private building. be able to.

  In addition, as shown in FIG. 1, the storage tank 20 and the rainwater outlet 22 b are connected via a water conduit 28, and the storage tank 20 and the sewer main line 14 are connected via a water conduit 26 and a return water pipe 30. It is. Here, the water conduit 26 is branched from the position 14 a upstream of the rainwater discharge chamber 16, and the return water pipe 30 is joined to the position 14 b downstream of the rainwater discharge chamber 16. .

  In the present embodiment, since the sewage is led from the rainwater spout 22b of the rainwater spout chamber 16 to the storage tank 20 via the water conduit 28, the water conduit 26 is not necessarily required. Instead of providing the overflow weir 22a, the rain water discharge port 22b, and the water conduit 28, a configuration in which the sewage upstream of the rain water discharge chamber 16 is guided to the storage tank 20 through the water conduit 26, or In order to increase the water conveyance capacity to the storage tank 20, the water conveyance pipe 26 and the water conveyance pipe 28 may be used in combination.

  Next, a specific example of the operation in the storage tank 20 will be described with reference to FIG. 6A is a diagram at the time of rain, and FIG. 6B is a diagram after the rain and at the time of operation of the water level sensor. As shown in FIG. 6, the storage tank 20 is provided with a water level sensor 20a to detect the stored water level. Further, the water guide pipe 28 and the return water pipe 30 are provided with gate valves 36 and 38, respectively. Furthermore, a gate valve 32 for adjusting the inflow amount of the building drainage and a gate valve 34 for adjusting the inflow amount of rainwater in the building site 18 are provided.

  At the time of rainfall, as shown in FIG. 6A, if the gate valve 36 is opened and the gate valve 38 is closed, sewage enters the storage tank 20 through the water conduit 28. The gate valves 32 and 34 may be set to an open or closed state depending on the situation. On the other hand, after the rain or when the water level sensor detects and operates the predetermined water level, as shown in FIG. 6B, if the gate valve 36 is closed and the gate valve 38 is opened, the inflow of sewage Is stopped, and the stored sewage is drained through the return pipe 30 to the sewer main line not shown. The gate valve 34 on the site rainwater side may be set in a closed state, and the gate valve 32 on the building drain side may be set open or closed depending on the building drainage.

  An example of the operation and action of the sewage / rainwater switching type storage facility 100 configured as described above will be described.

First, the case where initial sewage with a high pollution load is stored during rainfall will be described with reference to FIG.
In this case, as shown in FIG. 2, the gate valve (not shown) provided on the water conduit 28 side is opened, and the overflow water from the overflow weir 22a having a low weir height passes through the rainwater outlet 22b and the water conduit 28. It enters into the storage tank 20 in the site 18 of the building. In this case, when the flow rate of the sewage flowing through the sewer main line 14 exceeds a predetermined flow rate during rainfall or the like, the overflow water from the overflow weir 22a enters the storage tank 20 from the water conduit 28, so the storage tank 20 temporarily stores the sewage. Can be stored. Here, the sewage of the rainwater discharge chamber 16 overflows from the overflow dam 22a having a low dam height and does not overflow from the overflow dam 24a having a high dam height, so that the sewage flows into the river through the rainwater discharge port 24b. suppress. Therefore, water pollution of the river can be prevented.

  By the way, in the case of heavy rain such as typhoon or guerrilla heavy rain, the flow rate of sewage increases abruptly and a phenomenon in which sewage containing high-concentration pollutants flows down at the beginning of the rain, so-called fast flash occurs. FIG. 5 shows a transition example of the river pollution load at the beginning of rainfall. The horizontal axis represents date and time, the left vertical axis represents BOD (biochemical oxygen demand) / COD (chemical oxygen demand), and the right vertical axis represents SS (floating matter). In the example of this figure, the rain started to fall around 11:00 on September 8, 2010, and the BOD, COD, and SS of the river to be measured peaked around 14:00 immediately after that (see symbol P). You can see that you are greeted.

  Moreover, in the case of such heavy rain, there is a possibility that inundation will occur due to inadequate drainage of rainwater by sewerage. In this case, in order to suppress water pollution of the river, as shown in FIG. 2, if sewage containing high-concentration pollutants at the beginning of rainfall is temporarily stored in the storage tank 20, the pollution load of the river increases. Most of the factors can be removed and it is effective. On the other hand, in order to prevent flooding of internal water, building wastewater (for example, sewage such as rainwater or domestic wastewater other than rainwater) generated in the building site 18 may be temporarily stored as much as possible to suppress the amount of drainage to the sewer. .

Next, a case where overflow discharge to a river in the middle of rainfall is allowed will be described with reference to FIG.
In this case, as shown in FIG. 3, a gate valve (not shown) provided on the side of the water conduit 28 is closed, and overflow water from the overflow weir 24a having a high weir height is discharged to the river through the rain outlet 24b. Keep it like that. In this case, when the flow rate of sewage flowing through the sewer main line 14 exceeds a predetermined flow rate during rainfall, overflow water from the overflow weir 24a flows into the river. Here, the sewage of the rainwater discharge chamber 16 also overflows from the overflow overflow weir 22a having a low weir height. However, since the partition valve (not shown) provided on the water conduit 28 side is closed, the overflow water flows into the rainwater discharge port 22b. And it does not enter the storage tank 20 through the water conduit 28.

  On the other hand, rainwater in the building site 18 is stored in the storage tank 20. Here, it is preferable that the building drainage generated in the building site 18 is temporarily stored as much as possible, and the amount of drainage to the sewer is suppressed to prevent inundation. In this way, when there is a large amount of rainfall and there is a possibility of inundation, etc., it is effective to suppress the reception of overflow water from the combined sewer 10 and store rainwater in the site 18 of the building. .

  In the case of particularly heavy rain, as shown in FIG. 2, the overflow water generated at the beginning of the rain is temporarily stored in the storage tank 20, and in the middle of the subsequent rain, as shown in FIG. By storing sewage and rainwater such as generated domestic wastewater, the amount of drainage to the combined sewer 10 can be reduced and inundation can be prevented.

  At this time, since the sewage flowing through the sewage main line 14 of the combined sewer 10 is polluted water having a lower concentration than in the initial stage of rainfall, even if this sewage having a low concentration overflows the rainwater discharge chamber 16 and flows into the river, Compared with the case where the storage tank 20 is not installed, the influence on the river water quality can be reduced. Moreover, since this storage tank 20 can be utilized also for the storage of the rain water and domestic waste water in the site 18 of a building, it can also contribute to prevention of inundation.

Next, a case where the temporarily stored sewage is returned at the time of rain attenuation will be described with reference to FIG.
At the time of rainfall attenuation, the flow rate of sewage flowing through the sewer main line 14 is smaller than that during the rain and falls below a predetermined flow rate. Therefore, as shown in FIG. 4, from the overflow weirs 22a and 24a of the rain water discharge chamber 16 There is no overflow. In this case, a gate valve (not shown) provided on the return water pipe 30 side is opened, and the sewage temporarily stored in the storage tank 20 at the beginning of rainfall or the like is sewered downstream of the rain discharge chamber 16 through the return water pipe 30. Return to the main line 14.

  In the above embodiment, when the amount of rainfall is small and there is no risk of inundation, the sewage is received in the storage tank 20 of the sewage / rainwater switching storage facility 100 as shown in FIG. When there is a risk of flooding in the interior, as shown in FIG. 3, the amount of sewage received in the storage tank 20 is suppressed to temporarily store rainwater and domestic wastewater in the site 18 of the building. Also good. In this way, it is possible to effectively and economically prevent disasters such as improving river water quality and flooding inland water.

  In the above embodiment, the sewage / rainwater switching type storage facility 100 is more costly as the length of the conduit such as the water conduit 28 and the return water pipe 30 connecting the storage tank 20 to the sewer main line 14 and the rainwater discharge chamber 16 is shorter. Therefore, it is preferable to install it on a site such as a building near the river with a rainwater discharge chamber, but it is of course possible to install it on a site remote from the river. In this case, for example, a water flow branching part such as an overflow weir is provided in a part of the sewer near the building site, and this branching part and the storage tank in the building site are connected to a pipe like the water conduit 26 of this embodiment. It is conceivable to connect by road.

  Further, if a plurality of storage tanks 20 of the sewage / rainwater switching type storage facility 100 of the present invention are installed at any point in a district maintained by a combined sewer, the amount of overflow water flowing into the river through the rainwater outlet in that district The effect of reducing the risk of inundation is enhanced at the same time.

  Further, according to the sewage / rainwater switchable storage facility 100 of the present invention, it can be used as a combined sewage temporary storage facility or a rainwater temporary storage facility, and the scale of the storage facility can be reduced. Economic feasibility can be expected when a rainwater temporary storage facility and a combined sewage temporary storage facility are installed at the same time. In addition, it is possible to economically prevent flooding of inland water and reduce the environmental load on river water quality.

  In addition, even during heavy rains where there is a risk of inundation, storing the sewage equivalent to the so-called first flush at the beginning of the rain can prevent the first flush from flowing into the river, etc. It can prevent more effectively. In particular, even in rainfall with an hourly rainfall of about 5 mm / h, conventionally, overflow water has intermittently flowed into the river from a rainwater outlet, etc., which caused water pollution. Since sewage overflow from the rainwater outlet near the site is temporarily stored in a storage tank and is not discharged into public water areas such as rivers, it is advantageous in preventing water pollution.

  As described above, according to the sewage / rainwater switching type storage facility according to the present invention, the switching type storage facility having a storage tank that stores the sewage in the sewer and the rainwater in the building site in a switchable manner. In addition, since the storage tank is provided in the site of the building, a sewage / rainwater switching storage facility that can be used as a combined sewage temporary storage facility or a rainwater temporary storage facility is provided, for example, in a private building site. Can be realized economically.

  According to another sewage / rainwater switching type storage facility according to the present invention, the sewer is a combined sewer, and the storage tank receives sewage overflowed from an overflow weir provided in a rainwater discharge chamber of the combined sewer. Since it can be stored, it is possible to prevent water pollution caused by flowing from the overflow weir into a public water area such as a river.

  According to another sewage / rainwater switching type storage facility according to the present invention, the storage tank temporarily stores the sewage, and the stored sewage is returned to the sewer when the sewage flow rate of the sewer decreases. Since it is returned, the risk of inundation can be reduced.

  Further, according to another sewage / rainwater switching type storage facility according to the present invention, the storage tank receives the sewage when the rainfall is small, and suppresses the amount of the sewage received when the rainfall is large. Since rainwater in the building site is temporarily stored, it is possible to effectively and economically suppress the risk of water pollution and flooding of public water areas such as rivers.

  In addition, according to another sewage / rainwater switching type storage facility according to the present invention, the storage tank can store wastewater in the site of the building other than rainwater, so not only sewage and rainwater are stored, It can also be used as a building drainage temporary storage facility.

  As described above, the sewage / rainwater switching type storage facility according to the present invention is configured so that untreated sewage overflowed from a rainwater outlet or the like is discharged into a public water area such as a river when the combined sewer exceeds a certain flow rate during rainfall. It is useful for preventing water pollution caused by being discharged into the river, and is particularly suitable for effectively and economically preventing disasters such as improving the water quality of rivers and flooding inland water.

DESCRIPTION OF SYMBOLS 10 Combined sewer 12 Sewage treatment plant 14 Sewer main line 16 Rain water discharge chamber 18 Building site 20 Storage tank 20a Water level sensor 22a, 24a Overflow weir 22b, 24b Rain water discharge port 26, 28 Water guide pipe 30 Return water pipe 32, 34, 36, 38 Gate valve 100 Sewer / Rainwater storage facility

Claims (5)

A switchable storage facility having a storage tank for storing sewers in a sewer and rainwater in a building site in a switchable manner,
A sewage / rainwater switching type storage facility, wherein the storage tank is provided in a site of the building.   The said sewer is a combined sewer, The said storage tank can store the sewage which overflowed from the overflow weir provided in the rain water discharge chamber of the said combined sewer. Rainwater switching type storage facility.   The sewage / rainwater switching according to claim 1 or 2, wherein the storage tank temporarily stores the sewage, and returns the stored sewage to the sewer when the sewage flow rate of the sewer decreases. Type storage facility.   The storage tank is configured to receive the sewage when the amount of rainfall is small, and to temporarily store the rainwater in the site of the building by suppressing the amount of the sewage received when the amount of rainfall is large. The sewage / rainwater switching storage facility according to any one of claims 1 to 3.   The sewage / rainwater switching type storage facility according to any one of claims 1 to 4, wherein the storage tank is capable of storing wastewater in the site of the building other than rainwater.

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