JP2000334215A - Flocculating sedimentation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a clarified supernatant liquid by providing the above device with a mixing chamber capable of mixing and agitating a liquid to be treated and additives, a rotary chamber having a distributor to discharge the liquid to be treated into a sedimentation tank and a scraping blade for discharging deposits into the sedimentation tank. SOLUTION: When the liquid to be treated is clarified, the liquid to be treated is first made to flow out through a liquid to be treated introducing pipe into the mixing chamber 5 from the upper part of a liquid to be treated receiving chamber and the additives are injected to this liquid to be treated from an injection port. The liquid to be treated and the additives are then agitated by an agitating turbine 8 to flocculate the suspended materials, etc., in the liquid to be treated and to form flocculated floc. The liquid to be treated which includes the flocculated floc is evenly distributed into the sedimentation tank from a discharge hole 11a disposed at the distributor 11 of the rotary chamber. The deposits deposited on the bottom 10a of the rotary chamber are scraped by the scraping blade 17 to an aperture 16 and are discharged into the sedimentation tank via the aperture 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for coagulating and sedimenting suspended substances and the like in a liquid to be treated in a sedimentation tank to clarify the liquid to be treated.

[0002]

2. Description of the Related Art Conventionally, as a technique belonging to such a field, there is known a coagulating sedimentation apparatus in which a mixing chamber is fixed in a sedimentation tank and a rotating chamber having a distributor is rotatably provided at a lower end of the mixing chamber. ing. When a clear supernatant is obtained using such a coagulating sedimentation apparatus, a predetermined additive is introduced into the mixing chamber together with the liquid to be treated such as raw wastewater, and both are introduced into a turbine provided in the mixing chamber. And stir. Thereby, suspended substances and the like in the liquid to be treated aggregate to form flocs, and the liquid to be treated including the aggregated flocs is distributed and supplied from the distributor of the rotating rotating chamber into the sedimentation tank. Then, the flocculated flocs in the liquid to be treated settle and separate in the settling tank, and the clear supernatant liquid rises and flows out from the upper part of the settling tank.

[0003]

The coagulating sedimentation apparatus described above can efficiently obtain a clarified supernatant, and is used for various purposes such as wastewater treatment and papermaking white water recovery. However, as this type of coagulation and sedimentation apparatus has become widespread, the following problems have been pointed out.
That is, the liquid to be treated is continuously introduced from above into the mixing chamber of the coagulation sedimentation apparatus through a liquid introduction pipe or the like, and the liquid to be treated in the mixing chamber is supplied to the mixing chamber. Discharged from the distributor rotating below or below. On the other hand, the liquid to be treated in the mixing chamber contains particles having a relatively large specific gravity, suspended substances which aggregate in a short time by the action of the additive to form coarse flocs, and the like.

[0004] Therefore, these particles and coarse flocs settle in the mixing chamber and directly deposit in the bottom of the mixing chamber or in the rotating chamber functioning as the bottom of the mixing chamber before flowing into the distributor from the mixing chamber. Sometimes. When the sludge or the like is accumulated in the mixing chamber (at the bottom), the inlet of the liquid to be treated of the distributor is closed, and in some cases, the operation of the coagulation and sedimentation apparatus must be stopped. Further, if the inflow port of the liquid to be treated of the distributor is closed, the liquid to be treated cannot be efficiently distributed and supplied into the sedimentation tank, so that the clarity of the supernatant liquid deteriorates.

[0005] Therefore, an object of the present invention is to provide a coagulation sedimentation apparatus having excellent operation performance and capable of obtaining an extremely clarified supernatant.

[0006]

According to a first aspect of the present invention, there is provided a coagulation and sedimentation apparatus for coagulating and sedimenting suspended substances in a liquid to be treated in a sedimentation tank to clarify the liquid to be treated. In the apparatus, a mixing chamber fixed in a sedimentation tank, into which the liquid to be treated and the additive are introduced, and capable of mixing and stirring the liquid to be treated and the additive, and which functions as a bottom of the mixing chamber, A rotating chamber having a distributor rotatable about a central axis of the chamber and discharging the liquid to be processed from the mixing chamber into the sedimentation tank, an opening formed at the bottom of the rotating chamber, and fixed to the mixing chamber. And a scraping blade for discharging sediment deposited on the bottom of the rotating chamber from the opening into the settling tank.

[0007] Various liquids to be treated handled by the coagulation sedimentation apparatus include particles having relatively large weight, and suspended substances which are aggregated in a short time by the action of additives to form coarse flocs. . For this reason, these particles, coarse flocs, and the like may settle in the mixing chamber and accumulate on the bottom of the rotating chamber without flowing into the distributor. In view of this point, an opening is formed at the bottom of the rotating chamber included in the coagulation and sedimentation apparatus, and a scraping blade is fixed to the mixing chamber.

That is, during the operation of the coagulation and sedimentation apparatus, the rotating chamber rotates with respect to the mixing chamber, so that the scraping blade fixed to the mixing chamber rotates with respect to the rotating chamber. Become. As a result, the sediment deposited on the bottom of the rotating chamber during the operation of the coagulating sedimentation device is raked up to the opening by the scraping blade, and is discharged into the sedimentation tank through the opening. As a result, the inflow port of the liquid to be treated of the distributor is prevented from being blocked, and the liquid to be treated is always efficiently distributed and supplied into the settling tank. Therefore, the operation performance of the coagulation and sedimentation apparatus is improved, and the clarity of the supernatant is also improved.

A stirring turbine is disposed in the mixing chamber, is driven to rotate around the center axis of the mixing chamber, and mixes and stirs the liquid to be treated and the additive. It is preferable to further include a main shaft that is arranged so as to penetrate the center portion of the mixing chamber and that is driven to rotate around the center axis of the mixing chamber, and a bearing member fixed to the stirring turbine and supporting the main shaft from outside. .

With such a configuration, both the stirring turbine and the rotary chamber can be driven to rotate efficiently, and
It has a very high space efficiency. In this case, if particles or coarse flocs settle in the mixing chamber and excessively accumulate on the bottom of the rotating chamber,
Due to deposits entering between the bearing and the main shaft,
The main shaft and the bearing may be worn or damaged, or the main shaft may deviate from the center axis of the mixing chamber, that is, a so-called shaft runout may occur. On the contrary,
In this coagulation sedimentation apparatus, the deposits deposited on the bottom of the rotating chamber are scraped to the opening by the scraping blade and discharged into the sedimentation tank through the opening. Therefore,
Excessive accumulation of sludge and the like at the bottom of the rotating chamber is not caused at all, and occurrence of troubles due to deposits in the rotating chamber can be extremely effectively reduced.

Further, it is preferable to further comprise a short-circuit preventing member which is provided below the rotating chamber, is rotatable together with the rotating chamber, and blocks a flow of the liquid to be treated flowing into the precipitation tank through the opening.

In such a configuration, the flow of the liquid to be treated flowing out of the mixing chamber (rotating chamber) into the sedimentation tank through the opening is caused by the concentration formed below the rotation chamber in the sedimentation tank. Before reaching the sludge layer or the like, it is blocked by the short-circuit prevention member. Further, sludge and coarse flocs in the liquid to be treated flowing out from the opening are received by the short-circuit preventing member provided below the rotating chamber, and the sediment discharged from the opening into the sedimentation tank by the scraping blade is also included. Once received by the short-circuit prevention member. Then, since the short-circuit preventing member rotates together with the rotation chamber, the deposit on the short-circuit preventing member gradually falls to the lower portion of the sedimentation tank at a low speed by the action of the centrifugal force.

Thus, the liquid to be treated flowing out of the rotating chamber into the sedimentation tank through the opening directly reaches the concentrated sludge layer or the so-called short-circuit phenomenon, or is discharged from the rotation chamber into the sedimentation tank. The sediment prevents the flocculated floc and the concentrated sludge layer formed below the rotating chamber in the sedimentation tank from being diluted and stirred, so that the clarity of the supernatant can be maintained well. it can.

[0014] In addition to being provided above the opening,
A short-circuit preventing member rotatable with the rotating chamber and blocking the flow of the liquid to be processed into the opening; and a sweep-off blade fixed to the mixing chamber and sweeping off the deposits deposited on the short-circuit preventing member. It is preferable to further provide.

In this case, the flow of the liquid to be treated flowing into the opening formed at the bottom of the rotating chamber is:
It is blocked by a short-circuit prevention member provided above the opening. As a result, the liquid to be treated flowing out of the mixing chamber (rotating chamber) through the opening into the sedimentation tank directly reaches the concentrated sludge layer or the like. Since the flocculated floc and the concentrated sludge layer are prevented from being diluted and stirred, the clarity of the supernatant can be maintained satisfactorily.

Further, since the short-circuit preventing member rotates together with the rotation chamber, the sweeping blade fixed to the mixing chamber rotates with respect to the short-circuit preventing member. As a result, the deposits deposited on the short-circuit preventing member during the operation of the coagulation sedimentation device are washed off by the sweeping blade and flow into the distributor. Also,
The deposits that have been removed from the short-circuit preventing member by the removal blade and accumulated in the rotating chamber are raked up to the opening by the scraping blade and discharged into the settling tank through the opening.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the coagulation and sedimentation apparatus according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a partial sectional view showing a coagulating sedimentation apparatus according to the present invention. The coagulating sedimentation apparatus 1 shown in the figure can perform so-called sludge circulation operation and sludge blanket operation according to the characteristics of the liquid to be treated, and can perform wastewater treatment, papermaking white water recovery, DIP wastewater recovery, and caustic greening. It can be applied to various uses such as liquid clarification, water treatment, and inorganic precipitate washing treatment. The coagulating sedimentation apparatus 1 has a sedimentation tank 2 for clarifying a liquid to be treated such as raw wastewater.
Is formed in a bottomed cylindrical shape having a tank depth of about 4000 to 5000 mm. The diameter of the sedimentation tank 2 is set to 1500 to 3000 in accordance with the installation space and the characteristics and amount of the liquid to be treated.
It is set arbitrarily within a range of about 0 mm. The sedimentation tank 2
It is fixed on a base portion 3 provided in a space where the coagulation and sedimentation device 1 is installed. The base 3 is formed of concrete or the like.

The coagulating sedimentation apparatus 1 has a gantry 4 installed on the upper edge of the sedimentation tank 2. The gantry 4 is mainly used as a work space for workers during various maintenance work. A mixing chamber 5 is suspended from the center of the gantry 4. The mixing chamber 5 is formed in a cylindrical shape, and its height is set to, for example, about two thirds of the tank depth of the settling tank 2. The mixing chamber 5 is fixed to the gantry 4 with its central axis aligned with the central axis of the sedimentation tank 2. As a result, the mixing chamber 5 is arranged upright in the sedimentation tank 2 and a predetermined space (space) is formed between the lower edge of the mixing chamber 5 and the bottom surface of the sedimentation tank 2.

A liquid-to-be-treated introduction pipe 6 connected to a liquid-to-be-treated inflow pipe 6a connected to an external pump or the like is connected to the upper side surface of the mixing chamber 5. The liquid-to-be-treated introduction pipe 6 is provided below the clarified liquid level during the operation of the coagulation-sedimentation apparatus 1 and below the liquid level in the mixing chamber 5. Further, the mixing chamber 5 is provided with a plurality of injection nozzles 7 for injecting various additives for aggregating suspended substances and the like in the liquid to be treated. As the additive to be introduced into the mixing chamber 5, various polymer coagulants or the like are employed depending on the characteristics of the liquid to be treated. Each injection nozzle 7 is disposed along the height direction of the mixing chamber 5, and is provided, for example, one at a time in the upper, middle, and lower stages of the mixing chamber 5. Each injection nozzle 7 is connected to an additive introduction pump 7b via a header 7a, and an additive storage tank 7c is connected to a suction port of the additive introduction pump 7b. The injection amount of the additive can be controlled for each injection nozzle 7.

As shown in FIG. 1, the mixing chamber 5
Has a built-in stirring turbine 8 for mixing and stirring the liquid to be treated and the additive. The stirring turbine 8 includes a hollow cylindrical body 80 and a plurality of (in this case, 3 × 4 = 12) stirring blades 81 fixed to the outer peripheral surface of the cylindrical body 80. The center axis of the cylindrical body 80 is the mixing chamber 5.
Is rotatably suspended from the gantry 4 in a state of being coincident with the center axis. During the operation of the flocculation and sedimentation apparatus 1, the turbine drive unit 8a mounted on the gantry 4 is operated to rotate the stirring turbine 8 about the center axis of the mixing chamber 5. Further, a main shaft 9 is disposed inside the stirring turbine 8 so as to penetrate the center thereof.

The main shaft 9 is also rotatably suspended from the gantry 4 with its center axis coinciding with the center axis of the mixing chamber 5, and is driven by a driving unit 9a mounted on the gantry 4. Is driven to rotate about the central axis of The main shaft 9 has a rotating chamber (distribution supply machine) 1
0 is fixed. The rotation chamber 10 is connected to a lower end of the mixing chamber 5, functions as a bottom of the mixing chamber 5, and is rotatable around the center axis of the mixing chamber 5 by rotation of the main shaft 9.

Mixing chamber 5 and rotating chamber 10
A so-called non-contact type seal portion 14 is provided in the gap between the two. The seal portion 14 fixes the two sheet-shaped packings 15 to a flange formed on the lower edge of the mixing chamber 5, and the packing 15 is provided in a cylindrical engagement provided on the upper part of the rotating chamber 10. Part 10b
(See FIG. 4). As a result, the liquid to be treated flows directly from the gap between the mixing chamber 5 and the rotating chamber 10 into the sedimentation tank 2.
Discharge (short-circuit) is prevented. In this case, instead of the packing 15, a molded packing having a P-shaped cross section may be used, and the seal portion 14 may be configured as a grant packing or a mechanical seal.

A plurality of rotating chambers 10 (for example, 4
), And a plurality of blowout holes 11a are provided at a lower portion of each distributor 11.
(See FIG. 4 etc.). During the operation of the coagulation sedimentation apparatus 1, the rotating chamber 10 is rotated by the drive unit 9 a, and the liquid to be treated including the coagulation flocs is discharged into the sedimentation tank 2 from each outlet 11 a of each distributor 11. As a result, a uniform ascending flow is formed in the sedimentation tank 2 without causing a drift or a short-circuit flow.

The rotating chamber 10 has a baffle plate 12 located below each distributor 11.
Is attached. As a result, the liquid to be treated discharged from the outlet 11a is supplied to the lower part of the sedimentation tank 2 via the baffle plate 12, so that the distributor 1
The flocculation floc is prevented from being stirred by the liquid to be treated discharged from 1, and the sedimentation separation efficiency of the flocculation settling apparatus 1 is further improved. If the diameter of the distributor 11 is increased, the swirling flow may be excessively generated in the sedimentation tank.
It is good to form as a thing of small diameter. When the diameter of the sedimentation tank 2 is large, the number of distributors 11 may be increased, for example, 6, 8, 10, or 12.

On the other hand, as shown in FIG. 1, the tip of the spindle 9 to which the above-mentioned rotary chamber 10 is fixed is attached to the settling tank 2.
To the vicinity of the bottom of. A rake 21 and a cone scraper 22 that rotate together with the rotation chamber 10 are attached to the tip of the main shaft 9. The rake 21 is for stirring the sludge formed by settling of flocculated flocs in the liquid to be treated discharged from the distributor 11. As a result, a concentrated sludge layer is formed in a region below the rotating chamber 10 in the settling tank 2.

Further, the sedimentation tank 2 communicates with a sludge extraction pipe 23 penetrating through the base portion 3 at the center of the bottom surface, and the corn scraper 22 is connected to the sedimentation tank 2 and the sludge extraction pipe 23.
It is arranged at the connection part. The sludge extraction pipe 23 is connected to a sludge extraction pump 24 and a sludge return pump 25. When performing the sludge blanket operation, settling tank 2
The sludge extraction pump 24 is operated based on the indicated value of an interface detector (not shown) provided therein, and the concentrated sludge in the sedimentation tank 2 is discharged out of the system to keep the height of the interface of the sludge blanket layer constant. Keep in range. At this time, since the cone scraper 22 is rotating, the concentrated sludge in the settling tank 2 is uniformly discharged. When performing the sludge circulation operation, the sludge return pump 2 is operated based on the indicated value of the interface detector.
5 is operated to return and circulate the sludge.

The coagulating sedimentation apparatus 1 further includes a swirl flow preventing member 27 formed in a rectangular sheet shape from a sheet material such as a nylon sheet or cloth coated with vinyl. The swirling flow prevention member 27 is stretched between the inner peripheral surface of the sedimentation tank 2 and the outer peripheral surface of the mixing chamber 5, and partitions the inside of the sedimentation tank 2 in the radial direction. This allows
Even if a swirl flow is generated in the sedimentation tank 2 as the distributor 11 rotates, the swirl flow will collide with the swirl flow prevention member 27 when ascending in the sedimentation tank 2. Accordingly, the curling of fine flocs above the distributor 11 in the sedimentation tank 2 and below the surface of the clarified liquid is suppressed, so that the concentration of suspended particles in the supernatant can be reduced to a desired level. As a result, an extremely clear supernatant liquid rises in the precipitation tank 2 to form a clarified layer, and the supernatant liquid flows out of the system from an outlet 26 provided at the upper part of the precipitation tank 2.

Here, various liquids to be treated which can be handled by the coagulation and sedimentation apparatus 1 include particles having a relatively large specific gravity, coarse flocs, and the like. Therefore, when the liquid to be treated is directly poured into the mixing chamber 5 from the liquid introduction pipe 6 from the upper portion (when the liquid is introduced), particles having a large specific gravity settle immediately in the mixing chamber 5 and each of the rotating chambers 10 There is a case where the fluid accumulates on the bottom 10a (see FIG. 4) of the rotating chamber 10 without flowing into the distributor 11.

In view of this point, as shown in FIG. 2, the mixing chamber 5 of the coagulation / sedimentation apparatus 1 is in direct communication with the liquid introduction pipe 6 for introducing the liquid to be mixed into the mixing chamber 5. A target liquid receiving chamber 50 is provided. The liquid-receiving chamber 50 is constituted (defined) by an annular member 51 formed of an annular plate and a cylindrical member 52 formed in a cylindrical shape, and can be easily formed. The annular member 51 is provided with the liquid receiving chamber 50.
, Ie, a chamber bottom 50a, and the tubular member 52 forms a side wall of the liquid receiving chamber 50, ie, a chamber side wall 50b.

Between the chamber bottom 50a (annular member 51) and the chamber side wall 50b (tubular member 52) and the inner peripheral surface 5a of the mixing chamber 5, a space for flowing the liquid to be treated is defined. . Annular member 51 and tubular member 52
Is set such that a sufficient and sufficient volume of this space can be secured. In addition, the annular member 51
Is fixed to the inner peripheral surface 5a of the mixing chamber 5 so as to be located below the liquid introduction pipe 6 to be treated. Further, the upper end of the tubular member 52 fixed to the inner peripheral portion of the annular member 51 is located above the liquid introduction pipe 6 to be treated. This ensures that the liquid to be processed flows through the liquid-receiving chamber 50 before flowing into the mixing chamber 5.

In addition, the inner peripheral surface 5a of the mixing chamber 5 and the cylindrical member 52 are located near the liquid introduction pipe 6 to be treated.
The overflow prevention plate 53 is provided between the upper end of the spillover plate and the upper end of the spillover prevention plate. Accordingly, even if the flow rate of the liquid to be treated flowing into the liquid receiving chamber 50 from the liquid introducing pipe 6 is high, the liquid receiving chamber 50 is located near the liquid introducing pipe 6.
Thus, it is possible to prevent the liquid to be treated from immediately overflowing. As shown in FIGS. 2 and 3, the cylindrical body 80 (and the main shaft 9) of the stirring turbine 8 is inserted into the cylindrical member 52. Thereby, the space efficiency in the mixing chamber 5 can be improved.

As described above, if the processing liquid receiving chamber 50 is provided in the mixing chamber 5, the processing liquid introduction pipe 6
The liquid to be processed flowing out of the processing liquid flows into the processing liquid receiving chamber 50 and then flows into the mixing chamber 5. As a result, the amount of deposits on the bottom 10a of the rotating chamber 10 (see FIG. 4) can be effectively reduced. However, depending on the properties of the liquid to be treated, etc., the chamber bottom 5
In some cases, the suspended matter may accumulate at 0a, and in some cases, the outlet 60 of the liquid introduction pipe 6 may be blocked.

Based on this, the chamber bottom portion 50a, that is, the annular member 51, as shown in FIG. 3, is used to discharge deposits deposited in the processing liquid receiving chamber 50 into the mixing chamber 5. An outlet 55 is formed. In this coagulation sedimentation apparatus 1, the outlet 55 is 90 °
It is arranged at a total of four places at intervals. In this case, the outlet 5
5 is preferably 1/4 to 1/2 of the area of the chamber bottom 50a. Thereby, it is possible to prevent the liquid to be treated that has flowed into the liquid to be treated receiving chamber 50 from excessively flowing out of the discharge port 55 into the mixing chamber 5, and to close the discharge port 55 by deposits. Can be prevented. In order to prevent the discharge port 55 from being blocked by deposits, the opening width W (see FIG. 3) may be set to at least 30 mm or more.

As described above, if the discharge port 55 is provided in the chamber bottom portion 50a (the annular member 51), particles having a large specific gravity contained in the liquid to be treated in the liquid to be treated receiving chamber 50,
The coarse flocks and the like settle in the mixing chamber 5 through the discharge port 55, and deposits on the chamber bottom 50 a also flow through the discharge port 55 due to the flow of the liquid to be processed in the liquid to be processed receiving chamber 50. Mixing chamber 5
Is discharged into Thereby, a trouble such as the outlet 60 of the liquid-to-be-treated introduction pipe 6 being closed is eliminated, so that the operation performance of the coagulation and sedimentation apparatus 1 is improved.

On the other hand, the liquid to be treated flowing out of the liquid receiving chamber 50 into the mixing chamber 5 may contain particles having a relatively large specific gravity. The liquid to be treated also contains a suspended substance or the like which aggregates in a short time to form coarse flocs due to the action of the additive (polymer flocculant) supplied from the injection nozzle 7. For this reason, these particles and coarse flocs may settle in the mixing chamber and accumulate on the bottom 10a of the rotating chamber 10 without flowing into the distributor. Thus, the bottom 10 of the rotating chamber 10
If the sludge or the like is excessively deposited on a, the following problem may occur.

That is, as shown in FIG. 4, in the flocculation and sedimentation apparatus 1, both the stirring turbine 8 and the rotating chamber 10 are efficiently rotated and driven, and the rotating chamber 10 is fixed in order to improve the space efficiency. Spindle 9
Are arranged so as to penetrate the center of a stirring turbine 8 for mixing and stirring the liquid to be treated and the additive in the mixing chamber 5. At least at the lower end of the cylindrical body 80 of the stirring turbine 8, bearing members 82 (for example, four at 90 ° intervals) that support the main shaft 9 from outside are fixed. For this reason, if sludge or the like excessively accumulates on the bottom 10 a of the rotating chamber 10, the sediment enters between the bearing member 82 and the main shaft 9, and the main shaft 9 and the bearing member 82 are worn. -The shaft 9 may be damaged, or the main shaft 9 may deviate from the center axis of the mixing chamber 5, that is, so-called shaft deviation may occur.

In view of this point, an opening 16 for discharging sediment such as sludge into the sedimentation tank 2 is formed at the bottom 10a of the rotary chamber 10 included in the coagulation and sedimentation apparatus 1. As shown in FIG. 5, the coagulating sedimentation apparatus 1 is provided with one opening 16 near the main shaft 9 of the bottom 10a. As shown in FIGS. 4 and 5, the mixing chamber 5 is provided with a scraping blade 17 for discharging the deposits deposited on the bottom 10 a of the rotating chamber 10 from the opening 16 into the sedimentation tank 2. I have.

That is, a mounting block 18 is fixed to the lower inner peripheral surface of the mixing chamber 5, and the upper end of a support member 19 formed of an angle material or the like is fixed to the mounting block 18 via bolts or the like. Fixed. The support member 19 extends in parallel with the main shaft 9, that is, in the vertical direction. The scraping blade 17 is formed of an angle material or the like, and has a substantially L-shaped cross-sectional shape.
The scraper blade 17 is fixed to the lower end of the support member 19, the back plate 17a is located on the front side in the normal rotation direction of the rotating chamber 10, and the bottom plate 17b is substantially flush with the upper surface of the bottom 10a. Extend in parallel. The bottom plate 17b of the raking blade 17 and the bottom 10
It is preferable to set the interval between them to about 1 to 50 mm.

Here, as shown in FIG. 5, a straight line (diameter) extending substantially in parallel with the raking blade 17 and extending in the radial direction through the center of the main shaft 9 with respect to the bottom 10a of the rotating chamber 10 is formed. When set as the line R1, the scraping blade 17 is arranged such that the whole of the blade 17 is located on the reverse rotation direction (see the white arrow in FIG. 5) of the rotary chamber 10 with respect to the diameter line R1. By arranging the raking blade 17 in this manner, a force in a centrifugal direction (a direction toward the main shaft 9) acts on the deposit that comes into contact with the back plate portion 17a of the raiding blade 17. Therefore, if the scraping blade 17 rotates with respect to the rotation chamber 10,
The deposit is raked by the rake blade 17 toward the main shaft 9.

A short-circuit preventing member 20 for blocking the flow of the liquid to be treated flowing into the precipitation tank 2 through the opening 16 is provided below the rotation chamber 10 in the precipitation tank 2.
As shown in FIGS. 4 and 5, the short-circuit prevention member 20 is formed by forming a plate material into a disk shape, and is located below the opening 16, that is, the outer periphery is outside the outer edge of the opening 16. Is fixed to the main shaft 9. When the main shaft 9 rotates, the short-circuit preventing member 20 rotates the rotating chamber 1.
Rotates with 0.

Next, a procedure for clarifying the liquid to be treated by using the above-described coagulation / sedimentation apparatus 1 will be described.

In this case, first, the liquid to be treated introduction pipe 6
The liquid to be treated A is supplied to the mixing chamber 5 (see FIG. 1). At this time, the liquid to be treated A flowing out of the liquid to be treated introduction pipe 6 first flows into the liquid to be treated receiving chamber 50. Then, the liquid to be processed A flows through the space defined by the chamber bottom 50 a, the chamber side wall 50 b, and the inner peripheral surface 5 a of the mixing chamber 5, and then flows from the upper part of the liquid to be processed receiving chamber 50 to the mixing chamber. 5
It will flow out (spill out) inside.

As a result, compared with the case where the liquid A to be treated is directly introduced into the mixing chamber 5 from the liquid introduction pipe 6, particles or coarse flocs having a large specific gravity settle in the mixing chamber 5 and rotate. Bottom 10 of chamber 10
It is possible to extremely effectively reduce the deposition on a. As a result, the inflow port of the liquid to be treated of the distributor 11 is prevented from being blocked, so that the liquid to be treated A is always efficiently distributed and supplied into the sedimentation tank 2, and the operation performance of the coagulating sedimentation apparatus 1 is improved. This improves the clarity of the supernatant B (see FIG. 1).

With respect to the liquid to be treated A flowing into the mixing chamber 5 from the liquid to be treated receiving chamber 50, an additive is added at any timing from any or all of the injection nozzles 7 provided in multiple stages. Injected. As a result, the effect of the additive is maintained for a long time, and an aggregate floc having good sedimentation properties is formed. The liquid A to be treated and the additive in the mixing chamber 5 are stirred by the stirring turbine 8 which is driven to rotate by the turbine drive unit 8a, and the suspended substances and the like in the liquid A to be treated are aggregated to form aggregate flocs ( (Initial floc).

The liquid to be treated A containing the flocculated flocs is distributed and supplied into the sedimentation tank 2 from the distributor 11 of the rotating chamber 10 driven to rotate by the driving unit 9a. At this time, of the liquid to be treated A descending from the mixing chamber 5 toward the rotation chamber 10, the mixing chamber 5
The flow of the liquid to be treated A that is going to enter the gap between the liquid and the rotating chamber 10 is blocked by the seal portion 14. The liquid A to be treated including the flocculated flocs is evenly distributed into the sedimentation tank 2 from the outlet 11 a of the rotating distributor 11. As a result, a uniform upward flow is generated in the sedimentation tank 2, and a sludge blanket layer C is formed above the distributor 11. Among the flocs in the liquid A to be treated, those flocculated and separated in the sedimentation tank 2 are agitated by the rake 21 at the lower part of the sedimentation tank 2 to be concentrated sludge layer D.
To form

On the other hand, in the mixing chamber 5, some particles, coarse flocs and the like settle and accumulate on the bottom 10 a of the rotary chamber 10 without flowing into each distributor 11. Here, during the operation of the coagulating sedimentation apparatus 1, the rotating chamber 10 rotates with respect to the mixing chamber 5, so that the scraping blade 17 fixed to the mixing chamber 5 is conversely moved to the rotating chamber 10. It will rotate with respect to it. As a result, the deposits deposited on the bottom 10 a of the rotating chamber 10 during the operation of the coagulation and sedimentation apparatus 1 are raked to the opening 16 by the rake blade 17, and discharged into the sedimentation tank 2 through the opening 16. Will be done.

As a result, the bottom 10a of the rotating chamber 10
There is no possibility that sludge or the like will be excessively deposited on the surface of the rotating chamber 10, and troubles caused by deposits in the rotating chamber 10, such as blockage of the liquid inlet of the distributor 11, will be prevented. , The liquid to be treated A is always efficiently distributed and supplied. Therefore, the operation performance of the coagulating sedimentation apparatus 1 is improved, and the clarity of the supernatant B is also improved.

The flow of the liquid to be treated A flowing out of the mixing chamber 5 (rotating chamber 10) into the settling tank 2 through the opening 16 flows into the rotating chamber 10 in the settling tank 2.
Before reaching the concentrated sludge layer D formed below, it is blocked by the short-circuit prevention member 20. Similarly, sludge, coarse flocs and the like in the liquid to be treated A flowing out of the opening 16 are received by the short-circuit preventing member 20 provided below the rotating chamber 10, and are settled from the opening 16 by the scraping blade 17. The sediment such as sludge discharged into the inside is once received by the short-circuit prevention member 20. Since the short-circuit preventing member 20 rotates together with the rotating chamber 10, the deposit on the short-circuit preventing member 20 gradually and slowly sinks to the lower part of the sedimentation tank 2 by the action of the centrifugal force.

Thus, the sedimentation tank 2 is opened through the opening 16.
Due to the so-called short circuit phenomenon in which the liquid to be treated A flowing out into the concentrated sludge layer D or the like or deposits discharged from the rotating chamber 10 into the sedimentation tank 2, the rotating chamber 10 in the sedimentation tank 2 Since the flocculated floc and the concentrated sludge layer D formed below are prevented from being diluted and stirred, the clarity of the supernatant B can be maintained well.

From the concentrated sludge layer D, concentrated sludge E is withdrawn at any time by a sludge withdrawing pump 24 controlled based on an indicated value of an interface detector (not shown), whereby the interface height of the sludge blanket layer C is kept constant. Is kept within the range. On the other hand, the fine flocs in the upward flow are captured by the large flocs of the sludge blanket layer C. Further, the swirl flow generated with the rotation of the distributor 11 collides with the swirl flow prevention member 27. Accordingly, the winding of the fine flocs above the distributor 11 in the sedimentation tank 2 and below the clarified liquid surface is suppressed, so that the suspended particle concentration of the supernatant liquid B can be reduced to a desired level. This, extremely,
The clear supernatant liquid B rises in the settling tank 2 and a clear layer F is formed. The supernatant B flows out from an outlet 26 provided at the upper part of the sedimentation tank 2.

FIGS. 6 and 7 show another embodiment of the coagulation / sedimentation apparatus according to the present invention.

The coagulation and sedimentation apparatus 1A shown in FIG. 6 differs from the coagulation and sedimentation apparatus 1 shown in FIGS. That is, this coagulation sedimentation device 1
In A, the short-circuit preventing member 20A is fixed to the main shaft 9 so as to be located above the opening 16 formed in the bottom 10a of the rotating chamber 10. Accordingly, the flow of the liquid to be treated that is going to flow into the opening 16 formed in the bottom 10 a in the mixing chamber 5 is blocked by the short-circuit preventing member 20 </ b> A provided above the opening 16. As a result, the liquid to be treated flowing out of the mixing chamber 5 (rotating chamber 10) into the sedimentation tank 2 through the opening 16 directly reaches the concentrated sludge layer or the like. The sediment discharged into the tank 2 prevents the flocculated floc and the concentrated sludge layer formed below the rotating chamber 10 in the settling tank 2 from being diluted and agitated. Good clarity can be maintained.

Here, there is a possibility that sludge, coarse flocks and the like may accumulate on the short-circuit preventing member 20A provided above the opening 16. Based on this, the mixing chamber 5 of the coagulation and sedimentation apparatus 1A is provided with a wiping blade 28 for wiping off the deposits deposited on the short-circuit preventing member 20A. That is, the upper end of a support member 29 formed of an angle material or the like is fixed to the mounting block 18 fixed to the inner peripheral surface 5a of the mixing chamber 5 via a bolt or the like. Support member 29
Is opposed to a support member 19 supporting the scraping blade 17 with the mounting block 18 interposed therebetween, and extends in parallel with the main shaft 9, that is, in the vertical direction.

The sweeping blade 28 is formed of an angle material or the like and has a substantially L-shaped cross section. The sweeping blade 28 is fixed to the lower end of the support member 29, the back plate 28a is located on the front side in the normal rotation direction of the rotating chamber 10, and the bottom plate 28b is substantially flush with the upper surface of the bottom 10a. Extend in parallel. The distance between the bottom plate portion 28b of the sweeping blade 28 and the upper surface of the short-circuit prevention member 20A may be set to about 1 to 50 mm.

Here, as shown in FIG. 5, a straight line (diameter) extending in the radial direction passing through the center of the main shaft 9 while being substantially parallel to the sweeping blade 28 with respect to the bottom 10a of the rotary chamber 10 is formed. When set as the line R1, the scraping blade 17 is arranged such that the entire blade 17 is located on the side of the rotation chamber 10 in the normal rotation direction (see the white arrow in FIG. 7) with respect to the diameter line R1. By arranging the sweeping blade 28 in this manner, a force in a centrifugal direction (a direction toward the inner peripheral surface 5a of the mixing chamber 5) acts on the deposit that comes into contact with the back plate 28a of the sweeping blade 28. Will be. Therefore, if the sweep blade 28 rotates with respect to the rotating chamber 10, the sediment is removed by the sweep blade 2.
8, it is scraped in the direction toward the inner peripheral surface 5 a of the mixing chamber 5.

During the operation of the coagulating sedimentation apparatus 1A, the short-circuit preventing member 20A fixed to the main shaft 9 moves the rotating chamber 1
0 rotates together with the mixing chamber 5
The swaging blade 28, which is fixed with respect to, rotates with respect to the short-circuit prevention member 20A. As a result, the deposits deposited on the short-circuit preventing member 20A are removed by the blades 28.
, And flows into each distributor 11. Further, the rotating chamber 10 is removed from the short-circuit preventing member 20A by the removing blade 28.
The deposits deposited on the bottom 10a of the
As a result, it is scraped to the opening 16 and discharged into the sedimentation tank 2 through the opening 16.

[0058]

The coagulation and sedimentation apparatus according to the present invention is configured as described above, and thus has the following effects. That is, an opening is formed at the bottom of the rotating chamber, and a scraping blade that discharges deposits deposited at the bottom of the rotating chamber from the opening into the sedimentation tank is fixed to the mixing chamber. The treatment liquid inlet is prevented from being blocked, and the treatment liquid is always efficiently distributed and supplied into the precipitation apparatus. As a result, the operation performance of the coagulation sedimentation apparatus can be improved, and the clarity of the supernatant can be improved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a coagulation-sedimentation apparatus according to the present invention.

FIG. 2 is an enlarged partial cross-sectional view showing the vicinity of a connection between a mixing chamber and a liquid introduction pipe to be processed.

FIG. 3 is a sectional view taken along line III-III in FIG. 3;

FIG. 4 is an enlarged partial cross-sectional view showing the vicinity of a connection between a mixing chamber and a rotation chamber.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 is an enlarged partial cross-sectional view of a main part showing another embodiment of the coagulation sedimentation apparatus according to the present invention.

FIG. 7 is a sectional view taken along line VII-VII in FIG. 6;

[Explanation of symbols]

1, 1A: Coagulation sedimentation apparatus, 2: Sedimentation tank, 5: Mixing chamber, 6: Liquid to be treated, 7: Injection nozzle, 8:
Stirring turbine, 9 ... spindle, 10 ... rotating chamber, 10a
... bottom, 11 ... distributor, 16 ... opening, 1
7 ... raking blade, 18 ... mounting block, 19, 29
... Supporting members, 20 and 20A ... Short-circuit preventing members, 28 ... Peel off blades, 50 ... Liquid receiving chamber, 50a ... Bottom part of chamber, 50b ... Chamber side wall parts, 51 ... Circular member, 52 ... Cylinder member, 55 Discharge port, 80 ... cylindrical body, 8
DESCRIPTION OF SYMBOLS 1 ... stirring blade, 82 ... bearing member, A ... liquid to be processed, B ... supernatant liquid, C ... sludge blanket layer, D ... concentrated sludge layer, E
… Concentrated sludge, F… Clarified layer.

Claims (4)

[Claims] 1. A coagulation and sedimentation apparatus for clarifying a liquid to be treated by coagulating and precipitating suspended substances in a liquid to be treated in a sedimentation tank, wherein the liquid to be treated and the liquid to be treated are fixed in the sedimentation tank. While the additive is introduced, a mixing chamber capable of mixing and stirring the liquid to be treated and the additive, and functioning as a bottom of the mixing chamber,
A rotating chamber that is rotatable around a central axis of the mixing chamber and has a distributor that discharges the liquid to be processed from the mixing chamber into the precipitation tank; an opening formed at a bottom of the rotating chamber; A coagulating sedimentation device, comprising: a scraping blade fixed to the mixing chamber and configured to discharge deposits deposited on the bottom of the rotating chamber from the opening into the sedimentation tank. 2. A stirring turbine disposed in the mixing chamber and driven to rotate around a center axis of the mixing chamber to mix and stir the liquid to be treated and the additive; and the rotation chamber is fixed. A main shaft that is disposed so as to penetrate a center portion of the stirring turbine, and is driven to rotate around a center axis of the mixing chamber; and is fixed to the stirring turbine, and supports the main shaft from outside. The coagulating sedimentation apparatus according to claim 1, further comprising a bearing member that performs the coagulation. 3. A short-circuit preventing member, which is provided below the rotating chamber and is rotatable with the rotating chamber, and blocks a flow of the liquid to be treated flowing into the settling tank through the opening. The coagulation sedimentation apparatus according to claim 1 or 2, further comprising: 4. It is provided above the opening, and
A short-circuit preventing member rotatable together with the rotating chamber and blocking the inflow of the liquid to be processed into the opening; and a fixing member fixed to the mixing chamber, for removing deposits deposited on the short-circuit preventing member. 3. A blade according to claim 1, further comprising a blade.
3. The coagulation sedimentation apparatus according to 1.