JP2018202328A - Coagulator - Google Patents

Abstract

To provide a coagulator capable of suppressing furthermore adhesion of coagulation flocks.SOLUTION: A settling tank 1 separates coagulation flocks in treatment water. A sludge thickening tank 2 is surrounded by the settling tank 1, and collects and thickens coagulation flocks separated in the settling tank 1. A rotary member 4 is rotated around a revolving shaft R extending in a vertical direction inside the sludge thickening tank 2, between an internal wall surface 1a of the settling tank 1, and an external wall surface 2a of the sludge thickening tank 2. An impeller 6 is attached to the rotary member 4, and agitates treatment water.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a coagulation sedimentation apparatus, and more particularly to a coagulation sedimentation apparatus in which a coagulant is added before a sedimentation tank, and agglomeration flocs are increased in the sedimentation tank to form spherical pellets for precipitation.

  A coagulation sedimentation apparatus, which is a kind of water treatment apparatus, is widely used for water treatment, wastewater treatment, and the like. The coagulation settling device separates the raw water into sludge and treated water before the suspended matter contained in the treated water (raw water) flows into the settling tank or aggregates in the settling tank and precipitates in the settling tank. To do. At this time, the water to be treated supplied to the settling tank passes through a fluidized bed (sludge blanket) made of sludge. At this time, suspended substances and aggregated flocs in the treated water are trapped in the fluidized bed. Treated water is filtered.

  As the above coagulating sedimentation apparatus, the water to be treated to which the coagulant is added is agglomerated by stirring in a sedimentation tank, and further, the aggregation floc collision and rolling motion are repeatedly generated, thereby gradually increasing the particle size of the aggregation floc. There is known a granulation type agglomeration and precipitation apparatus which is increased in size to form spherical pellets. In this granulation type agglomeration settling apparatus, a fluidized bed (pellet blanket) can be formed using pellets having a high density and a high settling speed, so that higher speed processing is possible. Furthermore, since the water transmission line speed (LV) in the settling tank can be increased, the downsizing of the settling tank can be realized.

  However, the aggregated floc tends to adhere to other objects such as a wall surface and may become coarse when attached to other objects. The coarsened flocs become a lump and block the flow path in the settling tank, causing a drift in the settling tank. Such drift may disturb the fluidized bed and cause the aggregated floc in the fluidized bed to rise and flow out into the treated water.

  On the other hand, Patent Document 1 describes a coagulation sedimentation apparatus in which a guide rod that supports a stirring blade and a fixed blade fixed to a wall surface are provided in a precipitation tank that forms pellets. This agglomeration settling device prevents the agglomeration flocs from adhering to the wall surface, etc., by rotating the guide rod, and prevents the aggregation flocs from adhering to the wall surface, etc. It is possible to suppress the aggregated floc adhering to the stirring blade from becoming coarse and lump.

Japanese Patent No. 2723809

  However, in the technique described in Patent Document 1, even though the phenomenon that the flocs flocs over the plurality of stirring blades can be prevented, the center line of the guide rod that supports the stirring blades and the rotation axis of the guide rod Since the peripheral speed of the stirring blade is very slow at the position close to the guide rod and the fluidity of the floc is poor, the aggregated floc tends to adhere around the guide rod and on the stirring blade close to the guide rod. Also, because the peripheral speed is very slow and the fluidity near the guide rod is poor, the aggregate flocs grow easily on the guide rod and the stirring blade near the guide rod, and the aggregate flocs become a mass and drift in the sedimentation tank. There is a risk of producing.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a coagulation sedimentation apparatus that can further suppress the adhesion of coagulation floc.

  The coagulation sedimentation apparatus according to the present invention includes a sedimentation tank for separating the aggregated floc in the water to be treated, a sludge concentration tank that is surrounded by the precipitation tank and collects and concentrates the aggregated floc separated in the precipitation tank, and the sludge A rotating member that rotates between the outer wall surface of the sludge concentrating tank and the inner wall surface of the settling tank around a rotation axis that extends in the vertical direction inside the concentrating tank, and attached to the rotating member, And a stirring blade for stirring.

  According to the present invention, it is possible to further suppress the adhesion of the aggregated floc.

It is a schematic diagram which shows typically the pollution treatment apparatus of the 1st Embodiment of this invention. It is sectional drawing which showed typically the coagulation sedimentation apparatus of the 1st Embodiment of this invention. It is a perspective view which shows a part of coagulation sedimentation apparatus of the 1st Embodiment of this invention. It is a schematic diagram which shows typically the coagulation sedimentation apparatus of the 2nd Embodiment of this invention. It is a schematic diagram which shows the coagulation sedimentation apparatus of a comparative example.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to what has the same function, and the description may be abbreviate | omitted.

(First embodiment)
FIG. 1 is a schematic view schematically showing a pollution treatment apparatus according to the first embodiment of the present invention. A pollution treatment apparatus 100 illustrated in FIG. 1 includes a reaction tank 10, a communication pipe 20, and a coagulation sedimentation apparatus 30.

  The reaction tank 10 is a container for storing water to be treated (raw water) containing a turbidity component such as a suspended substance. To the water to be treated stored in the reaction tank 10, a flocculant that aggregates turbidity components in the water to be treated to form a floc floc and a pH adjusting agent for adjusting the pH of the water to be treated are added. Is done. In the present embodiment, the water to be treated is kaolin simulated waste water in which kaolin is suspended in filtered water obtained by filtering ground water. As the flocculant, PAC (polyaluminum chloride) that is an inorganic flocculant and polymer flocculence are used. And a cationic polymer as an agent. Further, the pH adjusting agent is caustic soda (sodium hydroxide).

  The reaction tank 10 has a stirrer 10a for stirring the water to be treated. The stirrer 10a rapidly stirs the water to be treated to which the flocculant has been added, and agglomerates the turbidity components in the water to be treated to form a floc floc. The aggregated floc formed in the reaction vessel 10 is a fibrous small floc.

  The communication pipe 20 communicates the reaction tank 10 and the coagulation sedimentation apparatus 30 and supplies water to be treated from the reaction tank 10 to the coagulation sedimentation apparatus 30. An accelerator for promoting the formation of aggregated flocs is added to the water to be treated while flowing through the communication pipe 20. In this embodiment, the accelerator is an anionic polymer. Aggregation floc can be increased by adding an accelerator to the water to be treated.

  The coagulation sedimentation apparatus 30 gently stirs the water to be treated supplied from the reaction tank 10 through the communication pipe 20 to grow the coagulation flocs, causes the coagulation flocs to collide with each other and roll, and form spherical pellets. By forming and precipitating these granules, the water to be treated is separated into sludge and treated water. More specifically, the agglomeration sedimentation apparatus 30 stirs the water to be treated, thereby causing the flocs to collide with each other, coarsening the flocs, and further causing mechanical dehydration and rolling motion by stirring to form spherical pellets. Concentrate to precipitate. The coagulation sedimentation apparatus 30 is connected to an extraction pipe 40 for taking out the separated treated water and a sludge extraction pipe 50 for taking out the separated sludge. On the sludge extraction pipe 50, a pump 50a for taking out the sludge is provided.

  Hereinafter, the coagulation sedimentation apparatus 30 will be described in more detail. FIG. 2 is a cross-sectional view schematically showing the coagulation sedimentation apparatus 30, and FIG. 3 is a perspective view showing a part (lower part) of the coagulation sedimentation apparatus 30.

  As shown in FIG. 2 and FIG. 3, the coagulation sedimentation apparatus 30 accommodates the water to be treated supplied from the reaction tank 10 through the communication pipe 20 and settles and separates the floc floc from the water to be treated. The sludge concentration tank 2 is surrounded by the settling tank 1 and collects and concentrates the aggregated flocs, and the stirring mechanism 3 that agitates the water to be treated.

  Although the sedimentation tank 1 and the sludge concentration tank 2 have a cylindrical shape in the example of a figure, they are not restricted to a cylindrical shape. For example, the sedimentation tank 1 and the sludge concentration tank 2 may have a prismatic shape or the like. Moreover, the sedimentation tank 1 and the sludge concentration tank 2 may have mutually different shapes.

  The center lines CL in the vertical direction (vertical direction) of the sedimentation tank 1 and the sludge concentration tank 2 coincide with each other in the example of the figure, but may be shifted from each other. The top of the sludge concentration tank 2 is set lower than the top of the sedimentation tank 1 so that the aggregated floc enters the sludge concentration tank 2 from the precipitation tank 1. An extraction pipe 40 is provided at the upper part of the sedimentation tank 1, and a sludge extraction pipe 50 is provided at the lower part (specifically, the bottom surface) of the sludge concentration tank 2.

  The stirring mechanism 3 includes a rotating member 4 that rotates in the settling tank 1, a motor 5 that is connected to the rotating member 4 and rotates the rotating member 4, and an agitating blade 6 attached to the rotating member 4. Have.

  The rotating member 4 rotates around the sludge concentration tank 2 around a rotation axis R extending inside the sludge concentration tank 2 substantially parallel to the center line CL of the sludge concentration tank 2. In the present embodiment, the center line CL of the sludge concentration tank 2 and the rotation axis R of the rotating member 4 coincide with each other.

  The rotating member 4 includes a support portion 4a coaxial with the center line CL (rotation axis R) of the sludge concentration tank 2, and side portions of the sludge concentration tank 2 (the inner wall surface 1a of the sedimentation tank 1 and the outer wall surface 2a of the sludge concentration tank 2). A stirring portion 4b extending substantially parallel to the rotation axis R, and a connecting portion 4c connecting the support portion 4a and the stirring portion 4b. The support part 4a is arrange | positioned above the sludge concentration tank 2 in this embodiment. A motor 5 is connected to the upper end of the support portion 4a, and the support portion 4a is rotated by the motor 5, so that the stirring portion 4b is surrounded by the sludge concentration tank 2 (the inner wall surface 1a of the sedimentation tank 1 and the sludge concentration tank). Between the two outer wall surfaces 2a). There may be one or more agitation units 4b. In the example of the figure, two stirring units 4b are provided, and the two stirring units 4b are provided at positions facing each other with the sludge concentration tank 2 interposed therebetween.

  The stirring blade 6 is attached to the stirring unit 4 b of the rotating member 4. A plurality of stirring blades 6 are provided and attached to each of the two stirring portions 4b. In the present embodiment, four stirring blades 6 are provided in each stirring unit 4b, and the four stirring blades 6 of each stirring unit 4b are arranged at equal intervals in the vertical direction.

  Further, the coagulation sedimentation apparatus 30 includes a fixed blade 7. The fixed blade 7 is attached to at least one of the inner wall surface 1 a of the sedimentation tank 1 and the outer wall surface 2 a of the sludge concentration tank 2. The fixed blade 7 is preferably attached to the inner wall surface 1a of the settling tank 1 on the side where the peripheral speed of the stirring blade 6 is relatively slow, of the inner wall surface 1a of the settling tank 1 and the outer wall surface 2a of the sludge concentration tank 2. It is more desirable to attach to both the inner wall surface 1a of the sedimentation tank 1 and the outer wall surface 2a of the sludge concentration tank 2. In the illustrated example, a plurality of fixed blades 7 are attached to both the inner wall surface 1 a of the sedimentation tank 1 and the outer wall surface 2 a of the sludge concentration tank 2. It is desirable that the stirring blades 6 and the fixed blades 7 are alternately arranged in the vertical direction. In the present embodiment, the fixed blade 7 is disposed between the stirring blades 6. Thereby, when the stirring blade 6 rotates, the stirring blade 6 and the fixed blade 7 pass each other.

  In the pollution treatment apparatus 100 having the above configuration, a flocculant and a pH adjuster are added to the water to be treated introduced into the reaction tank 10 in the reaction tank 10. The water to be treated to which the flocculant and the PH adjusting agent are added is rapidly stirred by the stirrer 10a in the reaction tank 10 to form a fibrous flocculent floc. The treated water containing the coagulation floc is supplied from the lower side to the sedimentation tank 1 of the coagulation sedimentation apparatus 30 via the communication pipe 20. At that time, the accelerator is added while flowing in the communication pipe 20 with respect to the water to be treated.

  The treated water supplied to the sedimentation tank 1 of the coagulation sedimentation apparatus 30 is gently stirred by the stirring mechanism 3. As a result, the collision and rolling motion of the agglomerated flocs repeatedly occur, the particle diameter of the agglomerated flocs gradually increases, and spherical pellets are formed. The pellets form a pellet blanket 31 that is a fluidized bed in the lower part of the settling tank 1 by its own weight and the upward flow of the water to be treated supplied to the settling tank 1 from below. Thereby, the layer 32 of the treated water in which the turbidity component is removed as pellets from the treated water is formed in the upper part of the sedimentation tank 1.

  The top of the pellet blanket 31 (the interface between the pellet blanket 31 and the treated water layer 32) gradually rises, and when the pellet reaches the top of the outer wall surface 2a of the sludge concentration tank 2, as shown in FIG. The sludge 33 is formed by being collected in the sludge concentration tank 2 beyond the outer wall surface 2 a of the tank 2 and concentrated in the lower part of the sludge concentration tank 2. The treated water in the settling tank 1 is taken out through the take-out pipe 40 and the sludge is taken out through the sludge take-out pipe 50.

  According to this embodiment demonstrated above, the sedimentation tank 1 isolate | separates the aggregation floc in to-be-processed water. The sludge concentration tank 2 is surrounded by the settling tank 1 and collects and concentrates the aggregated floc separated in the settling tank 1. The agitating portion 4b of the rotating member 4 has an inner wall surface 1a of the sedimentation tank 1 and an outer wall surface of the sludge concentration tank 2 around a rotation axis R extending in the sludge concentration tank 2 substantially parallel to the center line CL of the sludge concentration tank 2. Rotate between 2a. The stirring blade 6 is attached to the rotating member 4 and stirs the water to be treated. And since the sludge concentration tank 2 exists between the rotating shaft R and the stirring blade 6, the stirring blade 6 is located at a predetermined distance from the rotating shaft R. Therefore, compared with the case where the stirring blade is provided on the side surface of the rotating member positioned coaxially with the rotating shaft, this embodiment can increase the peripheral speed even in the portion near the rotating shaft R of the stirring blade 6. Therefore, the fluidity in the vicinity of the rotating shaft can be improved, and the adhesion of the aggregated floc can be suppressed.

  Moreover, in this embodiment, since the fixed blade 7 is attached to at least one of the inner wall surface 1a of the sedimentation tank 1 and the outer wall surface 2a of the sludge concentration tank 2, the aggregated floc attached to the stirring blade 6 by the fixed blade 7 is removed. It becomes possible to cut, and since the fluidity in the vicinity of the stirring blade can be further improved by passing each other, adhesion and coarsening of the flocs can be further suppressed.

(Second Embodiment)
FIG. 4 is a schematic view schematically showing a coagulation sedimentation apparatus according to the second embodiment of the present invention. Compared with the coagulation sedimentation apparatus 30 of the first embodiment shown in FIG. 2, the coagulation sedimentation apparatus 30 a of this embodiment shown in FIG. 4 directs the water to be treated as the rotating member 4 downward in the sedimentation tank 1. This is different in that a distributor 8 for discharging is provided.

  The distributor 8 is similar to the rotating member 4 of the first embodiment, around the sludge thickening tank 2 around the rotation axis R extending inside the sludge thickening tank 2 substantially parallel to the center line CL of the sludge thickening tank 2. It is a rotary distributor that rotates. In the present embodiment, the center line CL of the sludge concentration tank 2 and the rotation axis R of the distributor 8 coincide with each other.

  Similarly to the rotating member 4 of the first embodiment, the distributor 8 includes a support portion 8a that is coaxial with the center line CL of the sludge concentration tank 2, and a stirring that extends substantially parallel to the rotation axis R on the side of the sludge concentration tank 2. Part 8b, and connecting part 8c for connecting support part 8a and stirring part 8b. The support portion 8 a has a cylindrical shape and extends from the bottom surface of the sludge concentration tank 2 to above the sludge concentration tank 2. The motor 5 is connected to the upper end of the support part 8a, and when the support part 8a rotates by the motor 5, the stirring part 8b rotates around the sludge concentration tank 2. There may be one or more agitation units 8b. In the example of the figure, two agitation units 8b are provided, and the two agitation units 8b are provided at positions facing each other across the sludge concentration tank 2.

  The distributor 8 includes a first pipe portion 8f1 surrounding the support portion 8a above the sludge concentration tank 2. The agitating portion 8b and the connecting portion 8c of the distributor 8 are configured by a second piping portion 8f2 communicating with the first piping portion 8f1. An upper part of the first piping part 8f1 is provided with an inlet 8d that is opened upward and into which water to be treated is introduced. At the lower part of each of the two stirring sections 8b (second piping section 8f2), there is a supply port 8e that opens to the bottom and supplies the water to be treated introduced into the introduction port 8d to the settling tank 1. It is equipped. The 1st piping part 8f1 and the 2nd piping part 8f2 comprise the piping part 8f which connects the inlet 8d and the supply port 8e.

  The stirring blade 6 is attached to the stirring unit 8 b of the distributor 8. In the present embodiment, three stirring blades 6 are provided in each stirring unit 8b, and the three stirring blades 6 of each stirring unit 8b are arranged at equal intervals in the vertical direction. The fixed blade 7 is disposed between the stirring blades 6 in the vertical direction. Thereby, when the stirring blade 6 rotates, the stirring blade 6 and the fixed blade 7 pass each other.

  A second stirring blade 9 a is provided on the side surface of the support portion 8 a inside the sludge concentration tank 2. A plurality of second stirring blades 9a are provided in the vertical direction. The 2nd stirring blade 9a stirs the sludge accumulated in the sludge concentration tank 2, and suppresses fixation. A third stirring blade 9a is provided on the side surface of the support portion 8a included in the piping portion 8f1. A plurality of third stirring blades 9a are provided in the vertical direction. The third stirring blade 9b stirs the water to be treated and uniformly disperses the unreacted flocculant in the water to be treated.

  Also in the present embodiment described above, since the sludge concentration tank 2 exists between the rotating shaft R and the stirring blade 6, the stirring blade 6 is not in the vicinity of the rotating shaft R but has a predetermined distance from the rotating shaft R. To position. Therefore, compared with the case where the stirring blade is provided on the side surface of the rotating member positioned coaxially with the rotating shaft, this embodiment can increase the peripheral speed even in the portion near the rotating shaft R of the stirring blade 6. Therefore, it becomes possible to suppress the adhesion of the aggregated floc. Further, in this embodiment, since the rotating member 4 is constituted by the distributor 8, when the distributor 8 is used, it is not necessary to provide the rotating member 4 separately from the distributor 8, so that the apparatus can be simplified and the cost can be reduced. Reduction can be achieved.

  FIG. 5 is a cross-sectional view schematically showing a coagulation sedimentation apparatus of a reference example. In the coagulation sedimentation apparatus 30 ′ shown in FIG. 5, “(dash) is attached to the configuration corresponding to each configuration of the coagulation sedimentation apparatus 30 of the first embodiment shown in FIG. 2. Unlike the coagulation sedimentation device 30 of the first embodiment, the coagulation sedimentation device 30 ′ is provided with a sludge concentration tank 2 ′ on the wall surface side of the sedimentation tank 1 ′, and the rotating member 4 ′ is provided coaxially with the rotation axis R ′. It has been. For this reason, the peripheral speed of the stirring blade 6 ′ is close to 0 at a position near the rotating member 4 ′ of the stirring blade 6 ′ attached to the rotating member 4 ′.

  Hereinafter, as an example, the coagulation sedimentation apparatus 30 of the first embodiment shown in FIG. 2 is compared with the coagulation sedimentation apparatus 30 ′ of the reference example shown in FIG. 5. The reaction tank 10 and the communication pipe 20 are the same in the coagulation sedimentation apparatus 30 and the coagulation sedimentation apparatus 30 ', and the capacity of the reaction tank 10 is 200L. Moreover, the diameter of the sedimentation tank 1 in the coagulation sedimentation apparatus 30 and the coagulation sedimentation apparatus 30 'is 230 mm, the capacity is 35 L, and the height of the pellet blanket 31 is 55 cm.

  The treated water is kaolin simulated waste water, and its suspended solid content (SS) is 300 mg / L. To the water to be treated, 150 mg / L of PAC as an inorganic flocculant, 1.5 mg / L of a cationic polymer as a polymer flocculant, and 3.0 mg / L of an anionic polymer as an accelerator are added. Moreover, the amount of water to be treated is 830 L / h (linear velocity LV: 20 m / h).

Under the above conditions, after conducting a continuous water flow test for 10 hours for each of the coagulation sedimentation apparatus 30 of the first embodiment and the coagulation sedimentation apparatus 30 ′ of the reference example, the sludge adhering to the inside of the sedimentation tank 1 is obtained. Observed for lumps. The presence or absence of attached sludge was measured after the water flow was stopped and the blanket interface was lowered to the position where the stirring blades were exposed. Table 1 shows the observation results.

  As shown in Table 1, in the coagulation sedimentation apparatus 30 of the first embodiment, no lump of sludge could be confirmed, but in the coagulation sedimentation apparatus 30 ′ of the comparative example, the stirring blades were straddled by installing fixed blades. Although the sludge lump formed was suppressed, a sludge lump was confirmed on the stirring blade near the rotating member from the rotating member. Therefore, it was shown that the coagulation sedimentation apparatus 30 of this embodiment has an effect of suppressing the adhesion of the coagulation floc.

  In each of the embodiments and examples described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

DESCRIPTION OF SYMBOLS 1 Precipitation tank 2 Sludge concentration tank 3 Stirring mechanism 4 Rotating member 4a, 8a Support part 4b, 8b Stirring part 4c, 8c Connection part 5 Motor 6, 9a, 9b Stirring blade 7 Fixed blade 8 Distributor 8d Inlet 8e Supply port 8f Piping Part 10 Reaction tank 20 Communication pipe 30, 30a Coagulation sedimentation equipment 40 Extraction pipe 50 Sludge extraction pipe 100 Contamination treatment equipment

Claims (7)

A settling tank for separating the flocs in the water to be treated;
A sludge concentration tank that is surrounded by the settling tank and collects and concentrates the aggregated flocs separated in the settling tank;
A rotating member that rotates between the outer wall surface of the sludge concentration tank and the inner wall surface of the settling tank, with a rotation axis extending in the vertical direction inside the sludge concentration tank,
A coagulating sedimentation apparatus having a stirring blade attached to the rotating member and stirring the water to be treated.   The coagulation sedimentation apparatus of Claim 1 which has a fixed wing | blade attached to at least one of the inner wall surface of the said sedimentation tank, and the outer wall surface of the said sludge concentration tank.   The coagulation sedimentation apparatus according to claim 2, wherein the stirring blades and the fixed blades are alternately arranged in the vertical direction. The rotating member includes a support portion coaxial with the center line of the sludge concentration tank, a stirring portion extending between the outer wall surface of the sludge concentration tank and the inner wall surface of the settling tank, and the support. And a connecting part for connecting the stirring part and the stirring part,
The coagulation sedimentation apparatus according to claim 1, wherein the stirring blade is attached to the stirring unit. The rotating member is located at the upper part, the inlet for introducing the treated water, the lower part, the supply port for supplying the treated water introduced into the introducing port to the settling tank, and the introduction Having a piping part communicating the opening and the supply port;
The coagulation sedimentation apparatus according to claim 4, wherein at least the stirring unit is configured by the piping unit.   The coagulation sedimentation apparatus according to claim 4 or 5, wherein there are a plurality of the stirring sections.   The coagulation sedimentation apparatus of any one of Claim 1 thru | or 6 with which the centerline and the said rotating shaft of the said sludge concentration tank correspond.

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