JPS627335B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solid-liquid separator for concentrating sewage and the like in a combined sewer system and performing solid-liquid separation.

In a combined sewer system, a sewer system is provided that is connected directly to a pump station or a sewage treatment plant, and wastewater is guided for sewage treatment. When the weather is clear, only sewage is channeled, and pollutants are removed at the treatment plant, resulting in clean water that is then discharged into the river. In the event of rainwater, especially when heavy rain suddenly occurs, a rainwater discharge chamber is installed at an appropriate location along the route leading to the pumping station or treatment plant, and the relatively clean supernatant rainwater is gradually released into the river. The water is discharged and the remainder is sent to a pump station or treatment plant.

The capacity of a sewage treatment plant is usually the flow rate of sewage on a sunny day, q.
It is now possible to treat sewage with a flow rate of about 3q, which is three times the amount of wastewater. In the case of heavy rain, the amount of water that flows into the sewers far exceeds this 3q, so as mentioned above, the excess amount is overflowed from the rainwater outlet and discharged into the river, and the amount of water to be treated that goes to the sewage treatment plant is limited to 3q. However, a large amount of polluted overflow water flows into the river, causing water pollution and environmental pollution problems.

In order to prevent this, a storage tank with an overflow weir is installed in the middle of the sewage channel, and a solid-liquid concentration separation device is installed from this tank with a branch path.The entire amount of sewage on sunny days is guided to the separation device, and during heavy rain, the overflow weir is installed. The excess amount is discharged into the river, the amount less than that is led to a separation device, where it is separated from the water to be treated into a concentrated liquid containing a large amount of solids, and the treated clean water is discharged into the river and concentrated. Send the liquid to a sewage treatment plant. In this way, the amount of pollutants discharged into rivers can be reduced. However, in this case, if the separation equipment is not adjusted, the amount of treated water will increase as the inflow increases, and the amount of concentrated liquid will also increase, exceeding the capacity of the sewage treatment plant (3Q). Become.

The present invention improves the solid-liquid separator in order to deal with such cases, and it maintains the flow rate of the liquid to be treated at a predetermined level regardless of the increase in the amount of inflow of the water to be treated. It is an object of the present invention to provide a solid-liquid separator that can reduce the flow rate to below.

The present invention provides a tank having a substantially circular side wall and a bottom surface, an inlet for allowing water to be treated to flow in in a tangential direction to the side wall, and a part of the side wall for directing treated water after separation treatment to the outside of the tank. and a concentrated liquid discharge part that leads the concentrated liquid containing a large amount of separated solids to the outside of the tank. A solid-liquid separation characterized in that a flow rate adjustment mechanism is provided on one side, and the flow rate of the discharged water is adjusted by the flow rate adjustment mechanism according to the inflow amount of the water to be treated, so that the flow rate of the concentrated liquid is below a predetermined limit. It is a device that increases the flow rate of treated water to maintain the fluctuation of the water level in the tank within an approximately constant range even when the flow rate of the liquid to be treated increases, or to keep it below a predetermined water level, and to control the flow rate of the concentrated liquid. This is to prevent the value from exceeding a predetermined value.

Embodiments of the present invention will be described using the drawings.

In Figures 1, 2 and 3, separation tank 1
has a side wall 2 and a bottom surface 3 that are approximately circular (circular, oval, oval, similar circular shape, or spiral shape). This separation tank 1 has a side wall 2
The inlet 5 of the inflow pipe 4 is introduced in a tangential direction to give a swirling motion to the liquid in the separation tank 1.
is provided on the side wall 2. The inlet 5 may be partially located on the bottom surface 3, or may be located only on the bottom surface 3. The bottom surface 3 is inclined from the outer periphery toward the center. The bottom surface 3 may be formed as a horizontal surface, but it is more effective to have an inclined surface in order to accumulate precipitable solids at the center of the bottom surface.

A bottom discharge pipe 6 is installed near the center of the bottom surface 3 of the separation tank 1.
As described below, the precipitable solids contained in the liquid to be treated are accumulated at the bottom by swirling flow and secondary flow, separated, and discharged to the outside of the tank along with the concentrated liquid to be treated. . Further, when the amount of liquid flowing into the separation tank 1 decreases, the solid liquid stored in the tank is discharged to the outside of the tank.

An overflow pipe 7 is provided that passes through the center of the bottom surface 3 of the separation tank 1 and extends upward from the tank. This discharges floating solids and scum accumulated near the free surface 8 formed at the upper part of the separation tank 1 to the outside of the tank as a concentrated liquid together with the liquid to be treated flowing from the free surface 8 into the overflow pipe 7. It is something.

When the water level H ₁ in the tank is approximately constant, a certain amount of settled and floating solids are continuously removed from the bottom drain pipe 6 and overflow pipe 7 to the outside of the tank. The solids concentration will not exceed the upper limit. Therefore, the solid matter removal rate of the separation tank 1 does not decrease, nor does the processing capacity decrease. The bottom discharge pipe 6 and the overflow pipe 7 form a concentrated liquid discharge section for guiding the concentrated liquid containing a large amount of solids to the outside of the tank.

A discharge port 9 is provided in the side wall 2 of the separation tank 1 . This discharge port 9 is preferably provided as far as possible from the inlet port 5 along the flow direction around the side wall 2.

A discharge channel 10 having an overflow weir 11 is provided downstream of the discharge port 9. The minimum height of the overflow weir 11 is determined from the time when the amount of water to be treated flowing into the separation tank 1 exceeds a certain value and the water surface of the separation tank 1 reaches the upper end of the overflow pipe 7, and when it exceeds the overflow weir 11. It is preferable to set it so that it flows out. Examples of overflow weirs will be discussed later.

An overflow pipe 12 is provided downstream of the overflow weir 11 and connected to a river or the like. When the amount of rain increases and the amount of water exceeds the amount that can be treated at a sewage treatment plant, it is possible to remove pollutants and release it into rivers, etc.

Reference numeral 13 denotes a stabilizing plate, which is provided above the inlet 5 of the inflow pipe 4. This stabilizer plate 13 prevents the surface of the water in the tank from undulating and improves separation due to the difference in specific gravity. If it is too long, it will obstruct the secondary flow in the tank, so choose an appropriate length. It may be done as shown in FIG. 1A. If the stabilizing plate 13 is provided above the inlet, it will be easy to manufacture and will also serve as reinforcement, and since there is no support, solid objects will not get caught.

Reference numeral 14 denotes a storage tank for temporarily storing a concentrated liquid containing a large amount of floating or precipitated solids, and the concentrated liquid is sent to a sewage treatment plant via a pipe 16 by a pump 15. Reference numeral 17 denotes a water level detector which, via the controller 18, stops the pump 15 when the water level in the storage tank 14 exceeds _H4 , and stops the pump 15 when the water level decreases from _H4 to △ _H4 or more. Activate. When the water level exceeds _H4 and the water level still rises even after stopping the pump 15, a signal is sent to the operating section 19 of the flow rate adjustment mechanism (described later) of the discharge waterway 10 via the controller 18 for processing. The amount of discharged water is being increased.

The pump 15 may be a single pump or a plurality of pumps, and its flow rate is controlled by rotational speed control, number control, operation interval control, or a combination thereof. If the normal maximum flow rate in this flow rate adjustment range is adjusted to the maximum capacity flow rate of 3q of the sewage treatment plant mentioned above, there is no risk of sending more concentrated liquid than the treatment capacity. Then, the operation part 1
9 is operated to increase the flow rate of the discharge waterway 10.

20 is a water level detector that detects the water level in the separation tank 1, and the operation unit 19 is operated via the controller 21 according to changes in the water level _H1 , and when the water level _H1 increases, the discharge flow rate is increased. It's becoming like that. In other words, if the amount of inflow into separation tank 1 increases due to heavy rain, etc., the water level will decrease.
Since H ₁ becomes higher and the water level difference h ₁ increases, the amount of water flowing into the storage tank 14 exceeds 3q. To prevent this, the water level difference h ₁ must be kept almost constant, that is, the water level H ₁
should be kept almost constant. Therefore, by detecting the water level H ₁ and operating the operation unit 19 to increase the flow rate of the discharge waterway 10, it is possible to keep H ₁ almost constant and keep the flow rate entering the storage tank 14 at 3q.

In the above example, it is preferable that the storage tank 14 is provided with a separate emergency pump.

The operation of the embodiment as described above will be explained.

The sewage that has flowed into the separation tank 1 from the inlet 5 via the inflow pipe 4 circulates in the tank as a swirling flow in the direction of arrow 22, during which floating solids float to the water surface and settle. The solids settle on the bottom surface 3.

On the other hand, due to the swirling flow in the tank, as shown by the arrow 23, it descends along the side wall 2, moves toward the center along the bottom surface 3, rises along the outside of the overflow pipe 7, and flows toward the surroundings along the free surface 8. This creates a secondary flow that circulates in the opposite direction. The solids that have settled on the bottom surface 3 tend to gradually collect due to gravity due to the slope of the bottom surface 3, but this secondary flow collects them in the center in a shorter time and allows them to be collected more effectively than the bottom discharge pipe 6. It is discharged.

Further, relatively light floating solids float to the top and overflow from the upper end of the overflow pipe 7, but those with a specific gravity close to 1 are caught in the swirling flow and are difficult to float and separate. However, in this embodiment, the secondary flow is generated as described above and is gathered around the overflow pipe 7, so that the overflow can be easily and quickly removed.

When the inflow of water to be treated increases due to heavy rain, etc., the water level detector 17 detects that the pump 1
Alternatively, the operation unit 19 may be operated by detecting that the water level has risen above H _{4 even after stopping the water level H 4} , or the water level H ₁ may be detected by the water level detector 20 as described above. , a method may be used in which the operating unit 19 is operated when the value increases beyond the set value,
Alternatively, both may be used together. Alternatively, the inflow amount or the flow rate of other parts may be detected by a rotary type or weir type flow meter, and the operating section 19 may be operated based on the signal.

In this way, the operation unit 19 is operated to increase the discharge flow rate Q ₂ of the discharge waterway 10 to prevent increases in Q ₃ and Q ₄ and to maintain 3q to prevent overload of the sewage treatment plant.

Embodiments of the flow rate adjustment mechanism for the discharge flow rate are shown in FIG. 4 and subsequent figures.

The one shown in FIGS. 4a and 4b has a fixed weir 24,
It is combined with an elevating and lowering weir 25 that is raised and lowered by a drive device as an operating section 19.

In FIG. 5, an opening/closing lid 26 for changing the opening area of the discharge port 9 is also used.

The one shown in FIGS. 6a and 6b is a stack of removable weir plates 27 of different heights.
Many different heights can be obtained by selecting combinations. In this case, a display that displays the required height, etc. is used in place of the operation unit 19, and the user looks at this display and uses a combination that matches the height. Alternatively, the weir height can be estimated and combined based on the amount of rainfall.

7, 8 and 9 show a weir 11 with a triangular notch, a stepped notch and a circular notch,
In both cases, the width of the weir increases as the water level rises. Therefore, when the water level H ₂ rises, the flow rate ratio of Q ₂ /(Q ₃ +Q ₄ ) increases, Q ₂ increases, the flow rate is adjusted, and an increase in Q ₃ +Q ₄ can be prevented.

In FIG. 10, an elevating and lowering weir 25 is also used.

The present invention makes it possible to maintain the flow rate of concentrated liquid sent to the sewage treatment plant so as not to exceed a predetermined value even if the amount of inflow to the solid-liquid separator increases, and is simple in structure and control. This provides a solid-liquid separator and has extremely great effects.

[Brief explanation of the drawing]

The drawings relate to embodiments of the present invention; FIG. 1 is a plan view, FIG. 1A is a plan view of the vicinity of the stabilizer plate of another embodiment, FIG.
The figure is a - line sectional view of Figure 2, Figures 4 to 1.
0 shows an embodiment of the flow rate adjustment mechanism, FIG. 4a is a cross-sectional view of the discharge waterway 10, FIG. 4b is a cross-sectional view thereof, FIG.
is a cross-sectional view of the discharge waterway 10, and FIGS. 7 to 10 are cross-sectional views of the discharge waterway 10. 1...Separation tank, 2...Side wall, 3...Bottom surface, 4...
...Inflow pipe, 5...Inflow port, 6...Bottom discharge pipe,
7... Overflow pipe, 8... Free surface, 9...
... Outlet, 10... Outlet waterway, 11... Overflow weir, 12... Overflow pipe, 13... Stabilizer, 14...
Storage tank, 15...Pump, 16...Pipe line, 17...
Water level detector, 18...controller, 19...operation unit,
20...Water level detector, 21...Controller, 22,2
3...arrow, 24...fixed weir, 25...elevating weir, 26...opening/closing lid, 27...weir plate.

Claims (1)

[Scope of Claims] 1. A tank having a substantially circular side wall and a bottom surface, an inlet for allowing water to be treated to flow in in a tangential direction to the side wall, and a part of the side wall containing treated water after separation treatment. a discharge port that guides the separated concentrate to the outside of the tank, and a concentrate discharge section that guides the concentrated liquid containing a large amount of separated solids to the outside of the tank, and a discharge waterway is provided on the downstream side of the discharge port, and the discharge port or the discharge waterway A flow rate adjustment mechanism is provided in at least one of the above, and the flow rate of the discharged water is adjusted by the flow rate adjustment mechanism according to the inflow amount of the water to be treated,
A solid-liquid separator characterized in that the flow rate of the concentrated liquid is kept below a predetermined limit. 2. The device according to claim 1, wherein the flow rate adjustment mechanism is an overflow weir. 3. The device according to claim 2, wherein the height of the overflow weir can be adjusted. 4. The device according to claim 2, wherein the width of the overflow weir increases as the water level increases. 5. The device according to claim 1, wherein the opening area of the outlet is adjustable.