JP2006198571A - Precipitation device - Google Patents

Abstract

[PROBLEMS] To easily manufacture and transport in a factory, greatly reduce the installation period at the site, and to scrape and concentrate suspended substances precipitated and concentrated at the bottom of the sedimentation tank body. To provide a small-sized and low-cost precipitation device that can be easily discharged without requiring a machine and does not require a large number of inclined plates or fillers inside the precipitation tank body.
A rectangular sedimentation tank body 2 having no partition wall inside, an inlet trough (raw water inlet) 3 provided on one side upper part of the sedimentation tank body 2, and other sedimentation tank body 2 In a sedimentation apparatus 1 having an outlet trough (treated water discharge port) 4 provided at an upper side surface, a plurality of sludge pits 7 are provided at the bottom of the sedimentation tank body 2 in the direction from the inlet trough 3 to the outlet trough 4. .
[Selection] Figure 1

Description

  The present invention relates to a precipitation apparatus for precipitating suspended substances (sludge, sludge, etc.) contained in raw water to which a flocculant has been added and separating them.

  In wastewater treatment facilities such as sewage treatment facilities and chemical factories, raw water such as factory wastewater, river water, lake water, and well water is processed into clean water, and the water is reused or discharged into rivers, etc. Etc. are done. In a part of the treatment process, a precipitation apparatus is used in which a flocculant is added to raw water, and suspended substances contained in the raw water are precipitated and separated.

  By the way, as a conventional sedimentation apparatus, raw water is supplied from the side part slightly above the sludge pit of the main body of the sedimentation tank formed by attaching an inverted conical sludge pit to the bottom of the vertically long cylindrical part, and the supernatant water is used as treated water. The type of discharging from the upper part of the precipitation tank body is common.

  In addition, a precipitation device has also been proposed in which raw water is supplied from one side of a cubic or rectangular parallelepiped shaped precipitation tank body, and the supernatant water is treated and discharged from the other side of the precipitation tank body (Patent Literature). 1-3).

JP 2003-019403 A JP 2003-024709 A JP 2001-239106 A

  However, in the conventional sedimentation device formed into a vertically long cylindrical shape, although depending on the raw water load, the length of the cylindrical portion of the sedimentation tank body is 4 m or more, and the overall height is 4 to 6 m or more. Due to its high height, when the sedimentation tank body was manufactured at the factory, there was no easy means for conveying it. For this reason, construction work to manufacture and install the device is necessary, and the construction period becomes longer, and the shape of the main body is cylindrical, so the local plane space cannot be used. .

  On the other hand, in a sedimentation apparatus equipped with a rectangular shaped sedimentation tank body, the width is 4 m or more and the height is about 4 to 6 m depending on the raw water load, and in order to increase the sedimentation efficiency of suspended matter, In addition to providing a large number of inclined plates and filling with fillers, a scraper with a motor for discharging suspended solids that are precipitated and concentrated at the bottom of the tank is required. There was a problem of incurring a cost increase.

  The present invention has been made in view of the above problems, and the intended process is that it can be manufactured and transported easily at the factory, and the installation period at the site can be greatly shortened, and the settling tank Suspended matter precipitated and concentrated at the bottom of the main body can be easily discharged without the need for a powered scraper, and it is small and low in the number of inclined plates and fillers that do not need to be provided inside the precipitation tank body. It is to provide a cost settling device.

  In order to achieve the above-mentioned object, the invention described in claim 1 includes a rectangular sedimentation tank body having no partition wall inside, a raw water inlet provided on one side upper part of the precipitation tank body, and the sedimentation tank. In the sedimentation apparatus having a treated water discharge port provided on the other side upper part of the main body, a plurality of sludge pits are provided at the bottom of the settling tank body from the raw water inlet to the treated water discharge port. Features.

  According to a second aspect of the present invention, in the first aspect of the invention, each sludge pit includes a first inclined portion that descends from the raw water inlet side toward the treated water discharge port side, and the treated water discharge port. It has the 2nd inclination part which goes down toward the said raw | natural water inflow port, It is characterized by the above-mentioned.

  The invention according to claim 3 is characterized in that, in the invention according to claim 2, the inclination angle of the first inclined portion and the second inclined portion of each sludge pit is set to 30 ° to 70 °. To do.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the depth h of each sludge pit is h = (0.2 to 0) with respect to the water level H in the settling tank body. .8) It is characterized by being set to H.

  The invention according to claim 5 is the invention according to any one of claims 2 to 4, wherein a return portion for preventing the sludge from getting over is provided at the second upper end portion of any sludge pit. Features.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein a sludge extraction pipe for extracting the sludge is connected to the bottom of each sludge pit, and the sludge close to the raw water inlet It is characterized by controlling so that the amount of sludge extraction increases as the drawing tube.

  A seventh aspect of the invention is characterized in that, in the sixth aspect of the invention, a valve is provided in each sludge extraction pipe, and the opening degree of each valve is set to be larger as it is closer to the raw water inlet.

  The invention according to claim 8 is characterized in that, in the invention according to claim 6, the diameter of each sludge extraction pipe is set to be larger as it is closer to the raw water inlet.

  According to the first aspect of the present invention, since the precipitation tank main body has a rectangular shape such as a cube or a rectangular parallelepiped, it can be manufactured at the factory and easily transported to the site, and the plane space on the site can be utilized. This can be installed in a short period of time, and the construction period can be greatly shortened. In addition, since it is not necessary to provide a large number of inclined plates and fillers in the settling tank body, the structure of the settling tank body is simplified, and the size and cost can be reduced. Furthermore, suspended substances precipitated and concentrated at the bottom of each sludge pit provided along the direction from the raw water inlet to the treated water outlet at the bottom of the settling tank body are discharged from the bottom of each sludge pit. Therefore, suspended substances can be easily discharged without requiring a scraper with a motor.

  According to invention of Claim 2, in each sludge pit of a sedimentation tank main body, sedimentation of suspended solids in an inlet part is carried out by the 1st inclination part which goes down toward a treated water discharge port side from a raw | natural water inlet side. Since the distance is shortened, the sedimentation time of the suspended substance is shortened and the precipitation efficiency is increased. In addition, the second inclined portion that descends from the treated water discharge port toward the raw water inlet facilitates the collision of the suspended substance at the outlet with the second inclined portion, thereby preventing the suspended substance from carrying over. This improves the precipitation efficiency. Since the suspended substance can be naturally settled and concentrated at the center of the bottom of the sludge pit by the first inclined portion of the inlet portion and the second inclined portion of the outlet portion of each sludge pit, The precipitated suspended matter can be discharged easily and efficiently.

  According to invention of Claim 3, since the inclination angle of the 1st inclination part of each sludge pit and the 2nd inclination part was set to 30 degrees-70 degrees, it suspended, suppressing the height of a precipitation tank main body. Precipitation concentration of the substance can be performed well. If the tilt angle is too small, the natural sedimentation and concentration of the suspended solids is not good. Conversely, if the tilt angle is too large, the height of the tank needs to be increased. Accordingly, the inclination angle is preferably 30 ° to 70 °, and more preferably 40 ° to 60 °.

  According to invention of Claim 4, since the depth h of each sludge pit was set to h = (0.2-0.8) H with respect to the water level H of a sedimentation tank main body, the carry over of a suspended solid was carried out. While suppressing, it is possible to prevent unevenness of the amount of suspended matter precipitated in each sludge pit. If the ratio h / H of the sludge pit depth h to the water level H of the sedimentation tank main body is too small, the suspended matter is likely to carry over, and conversely if too large, the upper end of the second inclined portion Since the gap with the water surface is narrowed, the linear velocity of the water over the second inclined portion is increased, and the suspended matter is entrained and carry-over easily occurs. Therefore, the ratio h / H is preferably 0.2 to 0.8, and more preferably 0.3 to 0.5.

  According to the fifth aspect of the present invention, since the return portion is provided at the upper end portion of the second sloping portion of the sludge pit, the carry-over of suspended substances is suppressed and the precipitation efficiency is increased.

  According to the invention of claim 6, in order to control the sludge extraction pipe close to the raw water inlet, that is, the sludge extraction pipe connected to the sludge pit with a large amount of suspended solids, so that the amount of sludge extraction increases. Suspended substances that settle in each sludge pit can be reliably pulled out and discharged.

  According to the seventh aspect of the present invention, each sludge extraction pipe is provided with a valve, and the opening degree of each valve is set to be larger as it is closer to the raw water inlet. According to the eighth aspect of the invention, each sludge extraction pipe is set. As the diameter of the water is closer to the raw water inlet, it is possible to secure a drawing amount corresponding to the amount of suspended matter settled in each sludge pit, and to ensure that the suspended matter settled in each sludge pit is pulled out. Can be discharged.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 is a side sectional view of a precipitation apparatus according to the present invention, FIG. 2 is a plan view of a precipitation tank body of the precipitation apparatus, and FIGS. 3A to 3I are perspective views showing various forms of a return portion. .

  The precipitation apparatus 1 shown in FIG. 1 includes a rectangular parallelepiped precipitation tank body 2 that does not have a partition inside, and a raw water flow provided on one side upper part (the left side upper part in FIGS. 1 and 2) of the precipitation tank body 2. An inlet trough 3 as an inlet and an outlet trough 4 as a treated water discharge port provided at the other side upper part (upper right side in FIGS. 1 and 2) of the same sedimentation tank main body 2 are provided. As shown in FIG. 1, a raw water supply pipe 5 is connected to the inlet trough 3 of the settling tank body 2, and a treated water discharge pipe 6 is connected to the outlet trough 4.

  By the way, in the sedimentation apparatus 1 according to the present embodiment, three sludges in the direction from the inlet trough 3 to the outlet trough 4 (from the left to the right in FIGS. 1 and 2) are provided at the bottom of the sedimentation tank body 2. The pits 7 are juxtaposed, and the settling tank body 2 constitutes a three tank type settling tank.

  Each of the sludge pits 7 is tapered downward, and descends from the entrance side (left side in FIG. 1) toward the flat bottom 7c (from left to right in FIG. 1) on the entrance side. A first inclined portion 7a is provided, and rises from the bottom portion 7c toward the outlet side (from the left to the right in FIG. 1) on the outlet side (the right side in FIG. 1) (from the outlet to the inlet (the right side in FIG. 1) The second inclined portion 7b is provided, which is lowered from the left to the left).

  Here, the inclination angle θ1 of the first inclined portion 7a and the inclination angle θ2 of the second inclined portion 7b of each sludge pit 7 are both set to 30 ° to 70 °. The depth h of each sludge pit 7 is set to h = (0.2 to 0.8) H with respect to the water level H in the sedimentation tank body 2.

  A return portion 8 is provided at the upper end portion of the second inclined portion 7b of any sludge pit 7 to prevent carry-over of suspended matter (hereinafter referred to as “sludge”). In FIG. 1, a return portion 8 is provided at the upper end portion of the second sloping portion 7 b of the sludge pit 7 closest to the outlet trough 4 to prevent carry of sludge to the outlet trough 4. It is sure to prevent carry-over into water.

  Here, in the present embodiment, a roof-type object as shown in FIG. 3A is used as each return portion 8 (however, the second inclined portion 7b of the sludge pit 7 closest to the exit trough 4). 3 (a) in which the roof type as shown in FIG. 3 (a) is made into a left and right half in a side view), but the return portion 8 is made of sludge. Any structure can be used as long as it can prevent the second inclined portion 7b from being overcome, such as a cylindrical type as shown in FIG. 3B, as shown in FIGS. Elliptical column type, prismatic type as shown in FIGS. 5 (e) and (f), inclined plate type as shown in FIG. 5 (g), and ring slice as shown in FIG. A type or the like is adopted. On the other hand, as the return portion 8 provided at the upper end portion of the second inclined portion 7b of the sludge pit 7 closest to the exit trough 4, in addition to the one shown in FIG. 3 (i), the return portion 8 shown in FIGS. The thing of the shape which made the right-and-left half the thing of the structure from the side view can be used.

  On the other hand, a sludge extraction pipe 9 is connected to the bottom 7c of each sludge pit 7 of the sedimentation tank body 2, and each sludge extraction pipe 9 is provided with valves V1, V2, V3 and a flow meter 10, respectively. . A total of three sludge extraction pipes 9 extending downward from the bottom 7 c of each sludge pit 7 merge into the sludge pipe 11, and a pump 12 is provided in the middle of the sludge pipe 11. In the present embodiment, the three sludge extraction pipes 9 have the same diameter.

  Next, the operation of the precipitation apparatus 1 having the above configuration will be described.

  Raw water such as factory waste water or river water mixed with a flocculant is supplied from the raw water supply pipe 5 through the inlet trough 3 of the settling device 1 into the settling tank body 2 and flows toward the outlet trough 4. In addition, the sludge contained therein is naturally settled by gravity, and is precipitated and concentrated in three sludge pits 7 arranged in parallel at the bottom of the settling tank body 2.

  That is, in each sludge pit 7, the sludge that naturally settles is collected and precipitated at the center of the bottom 7c along the first inclined portion 7a on the inlet side and the second inclined portion 7b on the outlet side. The sludge is extracted from each sludge extraction tube 9 and discharged by driving the pump 12. And each sludge extracted by the three sludge extraction pipe | tubes 9 in total flows into the sludge pipe | tube 11, merges, is sent to the sludge treatment facility not shown from the sludge pipe | tube 11, and is used for a process.

  On the other hand, the raw water from which sludge has been separated and removed is discharged as treated water from the outlet trough 4 of the settling tank body 2 to the treated water discharge pipe 6 and reused or discharged into the river.

  By the way, the amount of sludge settled is as large as the sludge pit 7 which is close to the inlet trough 3 (that is, upstream of the flow direction of the raw water). The sludge extraction amount is also controlled so as to increase as the sludge extraction pipe 9 close to the inlet trough 3. Specifically, the opening degree of the valves V1, V2, and V3 provided in the sludge extraction pipe 9 is set to be larger as it is closer to the inlet trough 3. That is, the opening degrees of the valves V1, V2, and V3 are set to gradually decrease in this order. By setting in this way, it is possible to secure a drawing amount corresponding to the amount of sludge settling in each sludge pit 7, and it is possible to reliably draw out and discharge the sludge settling in each sludge pit 7.

  In addition, as another form which controls so that the sludge extraction amount per unit time from the sludge extraction pipe | tube 9 may increase so that the sludge extraction pipe | tube 9 close | similar to the entrance trough 3 may have a thing as shown, for example in FIG. Conceivable. 4 and 5, the same elements as those shown in FIG. 1 are denoted by the same reference numerals.

  In the embodiment shown in FIG. 4, the diameters φd1, φd2, and φd3 of the sludge extraction tubes 9-1, 9-2, and 9-3 are set larger as they are closer to the inlet (φd1> φd2> φd3). In FIG. 4, V is a valve.

  In the form shown in FIG. 5, pumps P1, P2, P3, valves V1, V2, V3 and a flow meter 10 are provided in each sludge extraction pipe 9, and the opening degree of the valves V1, V2, V3 is set to the inlet trough 3. The closer one is set larger, or the capacity of the pumps P 1, P 2, P 3 is set closer to the inlet trough 3.

  4 and FIG. 5, it is possible to secure an amount of extraction corresponding to the amount of sludge settled in each sludge pit 7, and the sludge settled in each sludge pit 7 is reliably extracted and discharged. can do.

  In the configuration shown in FIGS. 1 and 5, a sludge interface meter (not shown) can be installed in each sludge pit 7 in order to control the amount of sludge drawn from each sludge pit 7. . The amount of settled sludge in each sludge pit 7 is measured by a sludge interface meter, and the opening degree of the valves V1, V2, V3 can be adjusted according to the measured amount of settled sludge, and the sludge in each sludge pit 7 can be adjusted. The amount can be controlled efficiently.

  Furthermore, in each sludge pit 7, since the sludge settling distance at the inlet is shortened by the first inclined portion 7a, the sludge settling time is shortened and the settling efficiency is increased. Moreover, since the second sloping portion 7b promotes the collision of sludge with the second sloping portion 7b at the outlet portion, the sludge carry-over is prevented, and this also increases the precipitation efficiency.

  And in this Embodiment, since the return part 8 was provided in the connection part (top part) of the 2nd inclination part 7b of the adjacent sludge pit 7, and the 1st inclination part 7a, the carry over (climbing) of sludge is carried out. It is restrained by the return portion 8, and this also increases the precipitation efficiency.

  By the way, if the slant angles θ1 and θ2 of the first sloping portion 7a and the second sloping portion 7b of each sludge pit 7 are too small, the natural sedimentation and concentration of sludge will not be good. It is necessary to increase the height. Accordingly, the inclination angles θ1 and θ2 are preferably 30 ° to 70 °, and more preferably 40 ° to 60 °. In this Embodiment, since inclination-angle (theta) 1 and (theta) 2 were set to 30 degrees-70 degrees, the precipitation concentration of sludge was able to be performed favorably, suppressing the height of the sedimentation tank main body 2. FIG.

  Also, if the ratio h / H of the depth h of the sludge pit 7 to the water level H in the sedimentation tank body 2 is too small, sludge carryover is likely to occur, and conversely if too large, the upper end of the second inclined portion 7b. Since the space between the portion and the water surface is narrowed, the linear velocity of the water over the second inclined portion 7b is increased, and sludge is caught and the carry-over easily occurs. Therefore, the ratio h / H is preferably 0.2 to 0.8, and more preferably 0.3 to 0.5. In this Embodiment, since ratio h / H was set to 0.2-0.8, the carry over of sludge was suppressed and the treated water of favorable water quality was able to be obtained.

  Furthermore, in this embodiment, since the sedimentation tank main body 2 has a rectangular parallelepiped shape, it can be manufactured at the factory and easily transported to the site, and the local plane space can be used for a short period of time. This can be installed in between, and the construction period can be greatly shortened. In this embodiment, the shape of the sedimentation tank body 2 is a rectangular parallelepiped, but it is needless to say that it may be a cube.

  Further, in the precipitation apparatus 1 according to the present invention, since it is not necessary to provide a large number of inclined plates and fillers in the precipitation tank main body 2, the structure of the precipitation tank main body 2 is simplified, and the downsizing and cost reduction are achieved. It is done.

  Further, sludge precipitated and concentrated on the bottom of each of the three sludge pits 7 provided along the direction of the inlet trough 3 to the outlet trough 4 at the bottom of the settling tank body 2 is sludge from the bottom 7c of each sludge pit 7. Since each can be pulled out and discharged by the drawing tube 9, sludge can be easily discharged without requiring a scraper with a power machine.

  In the present embodiment, a three-tank settling tank in which three sludge pits 7 are provided at the bottom of the settling tank body 2 has been described. However, the number of sludge pits 7 is arbitrary, and four or more sludge pits are arranged in parallel. You may do it.

  In this embodiment, one hole is formed in the bottom portion 7c of each sludge pit 7, and the sludge extraction pipe 9 is connected to this hole. However, a plurality of holes are formed, or the bottom portion 7c of the sludge pit 7 is formed. The whole may be holes, and the sludge falling into these holes may be guided to the sludge extraction pipe 9.

  Next, specific examples will be outlined.

1 and FIG. 2, the precipitation apparatus having a three-tank settling tank main body contains 54 [m3] of raw water containing a concentration of about 190 [mg / L] of an inorganic suspended substance.
As a result of the treatment at a flow rate of / h], the concentration of suspended solids contained in the treated water at the outlet trough could be stably reduced to 15 mg / L or less.

  The present invention can be applied to all precipitation apparatuses for separating suspended substances in raw water by natural sedimentation by gravity.

It is side sectional drawing of the precipitation apparatus which concerns on this invention. It is a top view of the sedimentation tank main body of the sedimentation apparatus which concerns on this invention. (A)-(i) is a perspective view which shows the various form of the return part in the precipitation apparatus which concerns on this invention. It is a sectional side view which shows another form of the precipitation apparatus which concerns on this invention. It is a sectional side view which shows another form of the precipitation apparatus which concerns on this invention.

Explanation of symbols

1 Precipitation device 2 Precipitation tank body 3 Inlet trough (raw water inlet)
4 outlet trough (treated water outlet)
DESCRIPTION OF SYMBOLS 5 Raw water supply pipe 6 Treated water discharge pipe 7 Sludge pit 7a 1st inclination part 7b 2nd inclination part 7c Bottom part 8 Return part 9 Sludge extraction pipe 10 Flowmeter 11 Drainage pipe 12 Pump h Sludge pit height H Precipitation Water level in tank body P1 to P3 Pump V1 to V3 Valve θ1 Inclination angle of first inclined portion θ2 Inclination angle of second inclined portion

Claims (8)

A rectangular precipitation tank main body having no partition wall inside, a raw water inlet provided on one side upper part of the precipitation tank main body, and a treated water discharge outlet provided on the other side upper part of the precipitation tank main body. Having a precipitation device,
A sedimentation apparatus, wherein a plurality of sludge pits are provided in the bottom of the sedimentation tank body from the raw water inlet to the treated water outlet.   Each sludge pit has a first inclined portion that descends from the raw water inlet side toward the treated water discharge port side, and a second inclined portion that falls from the treated water discharge port toward the raw water inlet. The precipitation apparatus according to claim 1.   The precipitation apparatus according to claim 2, wherein an inclination angle of the first inclined portion and the second inclined portion of each sludge pit is set to 30 ° to 70 °.   The depth h of each sludge pit is set to h = (0.2 to 0.8) H with respect to the water level H in the settling tank main body. Precipitation equipment.   The sedimentation apparatus according to any one of claims 2 to 4, wherein a return portion for preventing sludge from getting over is provided at an upper end portion of the second inclined portion of any sludge pit.   6. A sludge extraction pipe for extracting sludge is connected to the bottom of each sludge pit, and control is performed so that the amount of sludge extraction increases as the sludge extraction pipe is closer to the raw water inlet. The precipitation apparatus in any one of.   7. A sedimentation apparatus according to claim 6, wherein a valve is provided in each sludge extraction pipe, and an opening degree of each valve is set to be larger as it is closer to the raw water inlet.   7. A sedimentation apparatus according to claim 6, wherein the diameter of each sludge extraction pipe is set to be larger as it is closer to the raw water inlet.

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