JP2006037510A - Rainwater reservoir facility in sewerage and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a cleaning frequency in a rainwater reservoir pond. <P>SOLUTION: This invention relates to a rainwater reservoir facility in a confluent type sewerage for introducing sewage and rainwater to a sewage treatment plant 2 by a common trunk flow passage. An overflow dam 3 is arranged in the trunk flow passage 1, and overflow water from this overflow dam 3 is taken in, and the taken-in overflow water is sent in the tangent direction of a screen 51 into the cylindrical screen 51 arranged in the vertical direction inside a cylindrical water tank 50, and a vortex flow is generated in the screen 51. While the liquid content is sent outside the water tank 50 via the screen 51 and is supplied to the rainwater reservoir pond 6, the solid content is gathered to a central lower part of the water tank 50, and this gathered solid content is extracted outside the water tank 50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rainwater stagnant technique in a sewer system that guides and treats sewage to a sewage treatment plant via a main channel.

  There are two types of sewerage: a sewer sewer that is configured to drain rainwater and sewage to the treatment facility using separate pipes, and a combined sewer that supplies water to the treatment equipment using the same pipe. The combined sewer system has been adopted by local governments mainly in large cities from the late Meiji period to the early Showa era, as the sewerage system has only one system, is easy to construct, and is inexpensive. Currently widely used.

  In combined sewers, a large amount of rainwater that exceeds the processing allowance may flow into the sewage treatment plant during rainy weather. Conventionally, the amount exceeding the allowable capacity overflows to a separate route from the normal processing route. The overflow water is discharged into public water areas such as rivers and seas by simple treatment such as untreated or coarse screens. However, it goes without saying that discharging such untreated or simplified treated overflow water is not preferable from the viewpoint of environmental load and hygiene.

  From such a point of view, installation of a rainwater catchment pond has been carried out as a measure against overflowing water in rainy weather (see, for example, Patent Document 1). A rainwater reservoir is a part of the rainwater overflow, which is used to store the amount of rainwater discharge load that is discharged from the combined sewer system by sending the stored water to the sewage treatment facility after the rain has ended. Reduction and the number of overflows can be reduced.

  However, in the conventional rainwater pond, the sedimentary substances such as sand contained in the sewage easily settle on the bottom of the pond or the foreign matter adheres to the wall surface during the storage period. And the cause of flies.

  In addition, in order to solve this problem, so-called flush cleaning (see, for example, Patent Documents 2 and 3) in which separately stored wash water is discharged and washed into the rainwater reservoir after the rain has ended, It has been proposed that a screen and a sand basin (sand pool) be installed in the previous stage to prevent sand and the like from flowing into the rainwater pond.

  For this reason, conventionally, it has been necessary to periodically perform manual cleaning, and many rainwater reservoirs are installed underground and have a large volume, so that there is a problem that a lot of labor and cost are required for cleaning.

On the other hand, in the case of sewerage sewers, when the flow of rainwater in the main line increases in rainy weather, etc., it is carried over to another route to be discharged or supplied to the storm water reservoir, so that sewage is not mixed Therefore, except for the fact that flies are less likely to occur, the basic problems are the same as for the confluence type, such as sand and foreign matter accumulating and adhering to the rainwater reservoir.
Japanese Patent Laid-Open No. 7-259745 JP 2004-116181 A JP-A-5-346016

  Therefore, the main problem of the present invention is to reduce the frequency of cleaning and to facilitate maintenance in a rainwater reservoir.

The present invention that has solved the above-described problems and the effects thereof are as follows.
<Invention of Claim 1>
A stormwater stagnation facility in a sewer system that guides and treats sewage to a sewage treatment plant via a main channel,
An intake channel for taking in overflow water from the main channel,
A solid-liquid separation device for solid-liquid separation of overflow water taken in by this intake channel;
A rainwater pond that is supplied with the liquid separated by the solid-liquid separator, and
The solid-liquid separation device includes a cylindrical water tank and a cylindrical screen vertically disposed inside the cylindrical water tank, and the overflow liquid is fed into the screen along the tangential direction of the screen. Eddy current is generated, and the liquid component is sent out of the water tank through the screen. is there,
Rainwater stagnant equipment in sewers characterized by that.

(Function and effect)
In this way, when the overflowed water is supplied to the rainwater reservoir, solid sediment is separated using a vortex-type solid-liquid separator so that sedimentary substances such as sand and impurities can be efficiently removed without reducing the supply efficiency. Can be removed well. More specifically, sedimentary substances such as sand are settled and separated (effect replacing the sedimentation basin), and non-sedimentable impurities are captured and separated by being drawn to the center of the vortex. Therefore, sand and other foreign substances flowing into the rainwater reservoir can be effectively reduced, and the frequency of cleaning can be reduced and maintenance can be facilitated.

<Invention of Claim 2>
The dehydrator to which the solid content separated by the vortex-type solid-liquid separator is supplied, and the storage unit to which the solid content separated by the dehydrator is supplied, and the solid content supplied to the storage unit is The storm water stagnation facility in the sewer according to claim 1, wherein the facility is configured not to be returned to the main channel.

(Function and effect)
The solid content mainly composed of residue (contaminants) separated by the vortex type solid-liquid separation device can be returned to the main channel and left to the treatment at the sewage treatment plant, but collected. It is inefficient to re-disperse the residue in the sewage of the main channel and collect it again at the sewage treatment plant. However, since the solid content separated by the vortex type solid-liquid separation device still contains a large amount of liquid content, it is not suitable for storage as it is.

  Therefore, in the invention described in this section, the solid content separated by the vortex type solid-liquid separation device is further dehydrated by the dehydrator, and the solid content separated by this dehydration treatment is stored in the storage section, It is constituted so as not to return to.

<Invention of Claim 3>
The rain water stagnation facility in the sewer system according to claim 1 or 2, further comprising a screen through which the overflow water passes and a scraper that scrapes off impurities trapped on the screen into the main channel.

(Function and effect)
By providing such a screen and a scraper, it is not necessary to take in coarse impurities mixed with overflow water, and the load of the subsequent solid-liquid separation process can be reduced.

<Invention of Claim 4>
A turbidimeter for measuring the turbidity of the overflow water supplied to the vortex solid-liquid separator is provided, and the solid content is intermittently removed from the water tank at a frequency according to the turbidity measured by the turbidimeter. The rainwater stagnation facility in the sewer according to any one of claims 1 to 3, wherein the facility is configured to be pulled out.

(Function and effect)
In this way, by configuring so that the solid content is extracted at a frequency according to the turbidity of the overflow water supplied, the change in the solid content storage amount corresponding to the change in the solid content content of the overflow water is properly captured. The solid content can be withdrawn when an appropriate solid content storage amount that does not cause problems such as a decrease in separation capacity is reached. Therefore, the drawing operation can be performed appropriately and with high efficiency.

<Invention of Claim 5>
The rainwater stagnant equipment in the sewer according to any one of claims 1 to 4, wherein liquid remaining in the water tank of the vortex solid-liquid separator is supplied to the rainwater catchment pond and washed. .

(Function and effect)
As described above, by using the vortex type solid-liquid separation device as a means for flushing the rainwater reservoir, it is possible to reduce flush washing facilities such as a flush gate and a flush tank.

<Invention of Claim 6>
In a sewer system that guides and treats sewage to a sewage treatment plant via a main channel,
The overflow water is taken in from the main channel, and the fetched overflow water is sent along the tangential direction of the screen into the cylindrical screen arranged vertically in the cylindrical water tank, and the vortex flow is generated in the screen. While sending the liquid component out of the water tank through the screen and supplying it to the rainwater reservoir, the solid content is collected at the bottom center of the water tank, and the collected solid content is drawn out of the water tank.
A method for stagnation of rainwater in a sewer.

(Function and effect)
The same effect as that of the first aspect of the invention can be achieved.

  As described above, according to the present invention, there are advantages such as reduction in the frequency of cleaning in a rainwater reservoir and facilitation of maintenance and management.

  FIG. 1 shows an embodiment in which the present invention is applied to a rainwater stagnant facility in a combined sewer. In other words, an overflow weir 3 is provided in the main channel 1 for the combined sewer system in which the sewage and rainwater are guided to the sewage treatment plant 2 through the common main channel 1, When the amount of rainwater supplied exceeds a predetermined amount, the overflow water from the overflow weir 3 is supplied to the vortex-type solid-liquid separator 5 via the intake channel 4 and the separated liquid is supplied to the rainwater catchment basin 6. Supplied and temporarily stored. The rainwater reservoir 6 is connected to a portion of the main channel 1 between the overflow weir 3 and the sewage treatment facility 2 via the outflow gate 7 and the outflow pipe 8, and for example, the rain stops when necessary. When the supply amount of sewage and rainwater falls below a predetermined amount due to the above, and there is room in the treatment amount of the sewage treatment facility, the outflow gate 7 is opened, and the stored water in the stormwater stagnation basin 6 is supplied to the sewage treatment plant 2. Are being supplied. The treated water treated in the sewage treatment plant 2 is discharged to a public water area such as the sea or a river through the discharge channel Y.

  2 and 3 show an example of the vortex type solid-liquid separator 5. The vortex type solid-liquid separation device 5 includes a cylindrical water tank 50 and a cylindrical screen 51 arranged vertically inside the cylindrical water tank 50. Further, the supply path 52 for supplying the liquid to be treated passes through the side of the water tank 50 and the side of the screen 51, and the overflow water is sent into the screen 51 along the tangential direction of the screen 51. Has been. A vortex flow is generated in the screen 51 by feeding the liquid to be processed. In addition, a liquid discharge path 53 is provided at the side of the cylindrical water tank 50, and a solid extraction part 50D is provided at the lower center. A drawing valve 5V and a drawing pump 5P installed outside are connected to the drawing portion 50D, and drawing control is performed by these.

  In the vortex type solid-liquid separation device 5 having such a cylindrical screen 51, the cylindrical screen 51 is provided as shown in FIG. 4, that is, the eyes of the screen 51 have a predetermined angle in the inner and outer directions of the screen 51. The cylindrical inner opening Mi of the eye is directed in a direction that does not oppose the flow direction of the inner Si vortex flow Fi of the screen 51, and the cylindrical outer opening Mo is opposite to the flow direction of the inner Si vortex Fi of the screen 51. It is preferable to adopt a configuration that is suitable for generating the flow of Further, as shown in the drawing, it is desirable that the surface A facing the vortex flow Fi of the screen 51 is formed in an arc surface. In the screen 51, the vortex flow Fi generated in the inner Si and the flow Fo opposite in the flow direction are generated on the outer side So of the screen 51, and the clear water can be effectively sent out of the tank. There is a feature that it is hard to be drawn into the eyes and hardly clogs. The screen width of the screen 51 may be determined as appropriate, but is preferably selected within the range of 1.2 to 5 mm.

  Further, the vortex type solid-liquid separation device 5 may be installed separately from the rainwater catchment basin 6, but is integrated with the rainwater catchment basin 6 as shown in FIGS. Arranging in a space is also a preferred form.

  In any case, according to the facility of the present embodiment, the supply efficiency is lowered by separating the collected overflow using the eddy current solid-liquid separation device 5 prior to supplying the overflow water to the rainwater reservoir 6. Accordingly, sedimentary substances such as sand and contaminants can be efficiently removed, and the frequency of cleaning can be reduced and maintenance can be facilitated without lowering the processing amount.

  The extraction of the solid content from the vortex solid-liquid separator 5 can be performed periodically or arbitrarily. However, since the solid content of the overflow water varies, the appropriate extraction timing also varies. Therefore, a turbidity meter 9 for measuring the turbidity of the overflow water is installed upstream of the vortex-type solid-liquid separator 5 in order to extract the solid content at an appropriate timing. It is preferable that the turbidity of the overflow water supplied to the liquid separator 5 is measured and the solid content is intermittently extracted at a frequency according to the measurement result. Specifically, a relationship between turbidity and an appropriate drawing time interval is examined in advance by a test operation or the like to determine a certain rule, and the drawing interval can be changed appropriately according to this rule.

  On the other hand, the solid content separated by the vortex type solid-liquid separation device 5 is returned to the main channel 1 through the flow path U indicated by the two-dot chain line by the above-described extraction valve 5V and the extraction pump 5P. Although it can be configured to leave it to processing, it is inefficient as described above. Therefore, after this separated solid content is supplied to the dehydrator 10 and reduced in volume by the dehydration process, the solid content separated by this dehydration process is stored in the storage unit 11 and is not returned to the main channel 1. It is also a preferable form. As the dehydrator 10, a screw press type, a press type, a roller type dehydrator or the like can be suitably used.

  In this case, the liquid component separated by the dehydrator 10 can be returned to the main channel 1 through the channel V indicated by the two-dot chain line in the figure, but is originally the component sent to the rainwater aquifer 6. Therefore, it is preferable that the rainwater catchment basin 6 is supplied via the flow path 12.

  In the present invention, a normal overflow weir 3 as shown in FIG. 7, that is, a groove-like flow passage 31 constituting the main passage 1 and a groove-like passage 32 constituting the intake channel 4 are arranged in parallel. The normal form which provided the overflow dam 3 between these can be employ | adopted. However, in this case, even coarse impurities are taken in along with the overflow water and are supplied to the vortex type solid-liquid separator 5, which may cause problems such as clogging.

  Therefore, it is a preferable embodiment to install a separation device for separating and removing coarse impurities on the upstream side of the vortex type solid-liquid separation device 5. In this case, the overflow water is supplied to the vortex solid-liquid separation device 5 as it is, that is, without adding a flocculant or the like after coarse impurities are separated and removed by the separation device. As this separation device, a separation device using a screen is preferable in that coarse impurities can be efficiently removed without hindering overflow. Particularly preferred is a bar screen device 30 as shown in FIGS. In this bar screen device 30, a bar screen 33 composed of a plurality of bars supported at a predetermined interval, a scraper 34 protruding between the bars and projecting to the supply side of the liquid to be treated, and the scraper 34 And a drive device such as a cylinder (not shown) that is moved along the longitudinal direction of the cylinder. The interval between the bars may be determined as appropriate, but is preferably selected within a range of 5 to 100 mm. The scrapers 34 are preferably provided at a plurality of positions with appropriate intervals in the longitudinal direction of the bar.

  Overflow water passes between the bars of the bar screen 33, but coarse impurities cannot pass between the bars and are separated. Contaminants such as clogged or caught between bars are scraped off by moving the scraper 34 along the longitudinal direction of the bar. Although not shown, it is also possible to install a water level meter on the liquid supply side of the bar screen 33 and operate the scraper 34 when a predetermined water level is reached according to the water level detection result.

  The coarse impurities separated by this separation device may be stored separately, but it is preferable to return to the main channel 1 from the viewpoint of simplification of equipment. Therefore, from this viewpoint, as shown in FIG. 10, it is preferable that the bar screen device 30 having the above-described scraper 34 is provided in the overflow weir 3 so that the overflow water passes through the bar screen 33. As a result, coarse impurities cannot pass through the bar screen 33, and by operating the scraper 34, foreign matters clogged in the screen 33 are returned to the main flow path 1.

  The installation posture of the bar screen device 30 with respect to the overflow weir 3 can be determined as appropriate. As shown in FIG. 10, the bar screen 33 is vertically provided on the overflow weir 3 along the vertical direction, as shown in FIG. As shown in FIG. 11A, the screen 33 is disposed horizontally and the overflow water is passed from the top to the bottom of the screen 33. The screen 33 is horizontally disposed as shown in FIG. Although not shown, a form in which the bar is extended in the vertical direction and a scraper is moved in the vertical direction can be employed.

  On the other hand, in the present invention, the adoption of the vortex-type solid-liquid separation device 5 reduces the residue in the pond such as sand which causes bad odor and flies, but it is not completely eliminated. Therefore, as shown in FIG. 1, flash cleaning means such as a flash gate 100 and a flash tank 101 can be provided. Moreover, as one preferable form, the rain water reservoir 6 can be flushed using the liquid remaining in the water tank of the vortex solid-liquid separator 5. For this purpose, a washing water supply passage is provided from the water tank 50 of the vortex-type solid-liquid separator 5 to the rainwater reservoir 6 and a flush valve is provided in the washing water supply passage. This flush valve is normally closed and necessary. It can be configured to perform flash cleaning by opening it according to the above. In this case, flash cleaning equipment such as a flash gate and a flash tank can be partially or entirely reduced.

  Moreover, in a general rainwater stagnant facility, a part of the overflow water taken from the main channel 1 may be taken into the rainwater stagnant pond 6 and the rest may be discharged directly into a public water area such as a river or the sea. This can also be adopted in the present invention. In FIG. 1, the discharge flow path W for this purpose is indicated by a two-dot chain line.

  Furthermore, in a general rainwater stagnant facility, a supply path for supplying sewage and rainwater directly to the sewage treatment plant 2 from the main channel 1 upstream of the overflow weir 3 may be provided. In FIG. 1, this supply path X is indicated by a two-dot chain line.

  The present invention is applied to a rainwater stagnant facility in a sewerage system that guides and treats sewage to a sewage treatment plant via a main channel. That is, the above embodiment is directed to a combined sewer that excludes rainwater and sewage with the same pipe, but the present invention is a separate sewer that excludes rainwater and sewage with separate pipes. It can also be applied to the system. In this case, except that sewage is not mixed with the overflow water, the basic part that takes the overflow water from the main channel that supplies rainwater to the sewage treatment facility and supplies it to the storm water reservoir through the vortex solid-liquid separator Including the application examples are basically the same as those in the above embodiment and can be easily understood by those skilled in the art.

  In addition, as the overflow water intake form, a form in which an overflow weir is provided as in the above embodiment is common, but even if it is other than the weir, if it is taken in by overflow using a water level difference, The invention can be applied.

  Furthermore, as a rainwater catchment basin 6 of a general rainwater catchment facility, it stores up to a predetermined storage allowance as in the above example, and the excess is discharged as it is into a public water area such as a river or the sea. Storage type, sedimentation type that supplies to the sewage treatment plant 2 by overflow, in principle, storage type / sedimentation type that supplies to the sewage treatment plant 2 by overflow, but discharges the excess when the supply amount to the rainwater reservoir 6 exceeds a predetermined amount The present invention can be applied to any of these.

  Furthermore, although the form shown in FIG. 1 is an example of application to a natural flow form in which rainwater / sewage supplied by natural flow is stored in the storm water reservoir 6, as shown in FIG. It can also be applied to a pumping station discharge form in which it is stored in the tank and sedimentary substances such as sand are removed and then supplied to the storm water reservoir 6 by the rainwater pump 103. In this pump station discharge form, sand and the like that are not removed by the sand basin 102 are complementarily removed by the vortex-type solid-liquid separator 5 prior to the supply to the storm water reservoir 6. On the other hand, the former eddy current type solid-liquid separation device 5 in the natural flow mode plays a role of removing sand and the like up to the sand basin 102.

It is a flowchart which shows the outline of the processing method of the overflow water concerning this Embodiment. It is a perspective view which shows the outline of an eddy current type solid-liquid separator. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a principal part expanded sectional view of a screen. It is a longitudinal cross-sectional view which shows schematically one form of a rainwater reservoir. It is a cross-sectional view which shows schematically one form of a rainwater reservoir. It is a perspective view which shows one form of an overflow dam. It is a front view which shows a bar screen apparatus schematically. It is a cross-sectional view which shows a bar screen apparatus schematically. It is a perspective view which shows the suitable form of an overflow dam. It is the schematic which shows the various installation forms of a bar screen apparatus. It is a flowchart which shows the example of the rainwater stagnant water equipment used as object.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Main line flow path, 2 ... Sewage treatment plant, 3 ... Overflow weir, 4 ... Intake channel, 5 ... Eddy current type solid-liquid separator, 6 ... Rainwater stagnation pond.

Claims (6)

A stormwater stagnation facility in a sewer system that guides and treats sewage to a sewage treatment plant via a main channel,
An intake channel for taking in overflow water from the main channel,
A solid-liquid separation device for solid-liquid separation of overflow water taken in by this intake channel;
A rainwater pond that is supplied with the liquid separated by the solid-liquid separator, and
The solid-liquid separation device includes a cylindrical water tank and a cylindrical screen vertically disposed inside the cylindrical water tank, and the overflow liquid is fed into the screen along the tangential direction of the screen. A vortex type solid-liquid separation device configured to collect the solid content at the center lower part of the water tank and draw out the collected solid content outside the water tank. is there,
Rainwater stagnant equipment in sewers characterized by that.   The dehydrator to which the solid content separated by the vortex-type solid-liquid separator is supplied, and the storage unit to which the solid content separated by the dehydrator is supplied, and the solid content supplied to the storage unit is The storm water stagnation facility in the sewer according to claim 1, wherein the facility is configured not to be returned to the main channel.   The rain water stagnation facility in the sewer system according to claim 1 or 2, further comprising a screen through which the overflow water passes and a scraper that scrapes off impurities trapped on the screen into the main channel.   A turbidimeter for measuring the turbidity of the overflow water supplied to the vortex solid-liquid separator is provided, and the solid content is intermittently removed from the water tank at a frequency according to the turbidity measured by the turbidimeter. The rainwater stagnation facility in the sewer according to any one of claims 1 to 3, wherein the facility is configured to be pulled out.   The rainwater stagnant equipment in the sewer according to any one of claims 1 to 4, wherein liquid remaining in the water tank of the vortex solid-liquid separator is supplied to the rainwater catchment pond and washed. . In a sewer system that guides and treats sewage to a sewage treatment plant via a main channel,
The overflow water is taken in from the main channel, and the fetched overflow water is sent along the tangential direction of the screen into the cylindrical screen arranged vertically in the cylindrical water tank, and the vortex flow is generated in the screen. While sending the liquid component out of the water tank through the screen and supplying it to the rainwater reservoir, the solid content is collected at the bottom center of the water tank, and the collected solid content is drawn out of the water tank.
A method for stagnation of rainwater in a sewer.

Images