JP3284225B2 - Coagulation sedimentation equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coagulating sedimentation apparatus used for treating water and sewage, industrial wastewater and other water.

[0002]

2. Description of the Related Art In the above-mentioned water treatment, the raw water is allowed to stand in a sedimentation basin to separate solid and liquid from the raw water. It is widely practiced to treat sludge as concentrated sludge. In recent years, various high-speed coagulation sedimentation apparatuses utilizing the coagulation sedimentation method of forming flocs using an inorganic coagulant and an organic polymer coagulant have been developed in order to respond to the necessity of increasing the treatment capacity of wastewater. . Further, when the treatment of the extracted sludge requires the discharge of high-concentration sludge, it is widely practiced to provide a thickening mechanism.

Conventionally, for example, a coagulation-sedimentation apparatus having such a concentrating mechanism as shown in FIG. 2 is known. This has a so-called sedimentation flocculation tank and a concentration mechanism integrated, and an inverted conical granulation sedimentation tank 2 is disposed inside a substantially cylindrical coagulation sedimentation tank 1. A stirring blade 3 is rotatably arranged inside the granulation settling tank 2 to form a granulation settling section 4. On the other hand, a scraper blade 5 is rotatably arranged at the bottom of the coagulation sedimentation tank 1, and a concentrating unit 6 for condensing the flocs or pellets formed in the granulation sedimentation tank to form a compact pellet is arranged. ing. Further, an inflow pipe 7 is connected to the lower part of the granulation and sedimentation tank 2, a sludge discharge pipe 8 is connected to the bottom of the coagulation and sedimentation tank 1, and a treated water outflow pipe 9 is connected to an upper end of the coagulation and sedimentation tank 1. ing.

The raw water into which the organic polymer flocculant and the like have been injected is guided from the inflow pipe 7 into the granulation sedimentation tank 2, and the stirring blade 3 inside the raw water is rotated to separate the raw water from the organic polymer flocculant and the like. By agitating, flocks, and furthermore, water inside these flocks is squeezed out to produce compacted and dense pellets. Then, the generated flocs or pellets overflow from the upper end 2a of the granulation and aggregation tank 2,
The overflowed flocs or pellets are deposited on the bottom of the coagulation sedimentation tank 1 and further settled and concentrated.
By rotating the raking blades 5, compact pellets are formed, the pellets are raked toward the center, and are discharged to the outside from a mud pipe 8 provided at the center.

[0005] Here, a high concentration and stable blanket layer is formed by the dense pellets in the inside of the granulation and aggregation tank 2, and the raw water is filtered while passing through the blanket layer. The supernatant liquid collected in the upper part of the coagulation sedimentation tank 1 is discharged outside from the treated water outflow pipe 9 and treated as treated water.

[0006]

However, in the above conventional example, for example, the suspended solids concentration (SS) is 50 pp.
m or less, for raw water, although the desired treatment can be performed, for example, when trying to treat raw water having a suspended matter concentration of more than 100 ppm, pellets overflowing from the upper end of the granulation and coagulation tank are too concentrated, Clogging may occur between the granulation and coagulation tank and the coagulation and sedimentation tank, which may hinder this treatment.

A so-called horizontal type in which a granulation settling tank and a concentration tank are arranged in parallel with each other, and pellets overflowing from the granulation settling tank are guided into a concentration tank adjacent to the granulation settling tank. Although there is also known a horizontal type, there is a problem that a large installation space is required.

The present invention has been made in view of the above circumstances, and is an integral type having a concentration mechanism, and can reliably perform this treatment even if the concentration of suspended solids is, for example, 100 ppm or more of raw water. It is an object of the present invention to provide a coagulating sedimentation apparatus having a compact structure and capable of efficient water treatment.

[0009]

The coagulation and sedimentation apparatus of the present invention comprises a granulation and coagulation apparatus disposed in an upper part of a sedimentation tank and disposed in a partition wall for forming flocs by sedimenting raw water to which a coagulant is added. Part, an umbrella-shaped dispersion plate disposed below the lower opening of the granulation aggregation part, a baffle plate disposed on the inner wall of the sedimentation tank beside the umbrella-shaped dispersion plate, and a sedimentation tank It is characterized by comprising a concentrating mechanism arranged at the bottom of the inside to stir and further concentrate the settled concentrated aggregates, and an overflow portion arranged at the top of the sedimentation tank.

According to the present invention described above, the floc formed by the granulation / aggregation section arranged at the upper part of the tank is replaced with the blanket formed by the umbrella-shaped dispersion plate and the rectifying plate arranged at the middle part of the aggregation / sedimentation tank. By passing through the layer, solid-liquid separation is promoted, and the solidified aggregates are settled at the bottom of the coagulation sedimentation tank, scraped by a scraper, and taken out as dense pellets. Therefore, the raw water containing the coagulant injected from the upper part of the coagulation sedimentation tank is granulated and precipitated as it proceeds downward, and after passing through the granulation coagulation part, the pellets are densified by passing through the blanket layer in the middle part of the coagulation sedimentation tank. The pellets are separated into a supernatant and a supernatant, and the pellets fall into a concentrating mechanism arranged at the bottom of the coagulation sedimentation tank, are concentrated, and are taken out as dense pellets. Further, since the raw water is filtered through the dense blanket layer, a clear supernatant liquid is obtained and discharged from the upper part of the tank. Therefore, since there is no portion that becomes a bottleneck for the passage of the coagulated material as in the conventional coagulating sedimentation apparatus, it is possible to stably produce dense pellets even with a vertical compact structure and a high concentration of contaminated raw water. Can be.

[0011]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG.

In this embodiment, after adding and mixing an inorganic coagulant to raw water, a fibrous aggregate is generated by the adhesive activity of the inorganic coagulant, and then an organic polymer coagulant is injected. This shows an example in which granulation is carried out. As shown, a mixing tank 1 having a raw water inflow pipe 10 connected to the bottom thereof.
An inorganic coagulant is injected into the raw water flowing into the mixing tank 11 from the raw water inflow pipe 10, and the raw water is supplied to the mixing tank 1.
The raw water and the inorganic coagulant are mixed while spirally flowing upward in 1, and fibrous aggregates are generated.

A substantially cylindrical coagulation sedimentation tank 12 is provided on the side of the mixing tank 11, and a substantially cylindrical partition wall 13, which is a granulation aggregation part, is concentrically formed inside the coagulation sedimentation tank 12. Are located. The inside of the partition wall 13 and the inside of the mixing tank 11 are communicated with each other at an upper portion thereof by an inflow pipe 14, and the raw water in which fibrous aggregates are generated in the mixing tank 11 is inside the partition wall 13. To be press-fitted. An injection port 15 for injecting the organic polymer flocculant is provided in the middle of the inflow pipe 14. As a result, the raw water in which the inorganic coagulant is added and the fibrous coagulate is precipitated flows in the inflow pipe 14, and the organic polymer coagulant is injected in the middle thereof and introduced into the partition wall 13. . And the partition 13
It is configured such that a granular sediment is generated in the process of sedimentation in the inside.

That is, a first rotating shaft 21 and a second rotating shaft 22 are arranged concentrically inside the partition wall 13.
These rotary shafts 21 and 22 are individually driven via a motor 23. Here, the partition wall 1
3, a pre-mixing blade 31 is attached to the first rotating shaft 21 so as to protrude radially. As a result, the raw water into which the organic polymer flocculant has been injected is contained in the raw water by the action of the organic flocculant, in particular, while the raw water is settling from the inside of the partition wall 13 to the inside of the cylindrical body 28 of the rotating body 25. Granulation sedimentation in which the fibrous aggregate grows into a granular aggregate sediment (floc) is performed. During this time, the generation of flocs can be promoted by stirring with the stirring blades 31.

The first rotating shaft 21 has a rotating body 25 having a first stirring blade 24a and a second stirring blade 24b.
However, an umbrella-shaped dispersing plate 26 is connected to the second rotating shaft 22 below the rotating body 25, and further, the ends are aggregated in opposition to the umbrella-shaped dispersing plate 26. Settling tank 1
A radial baffle plate 27 fixed to the inner peripheral surface of the second baffle 2 is disposed.

The rotating body 25 is provided with a cylindrical body 28 extending downward from the partition wall 13.
8 is provided with the first stirring blade 24a and the second stirring blade 24b. The umbrella-shaped dispersion plate 26 is formed in an umbrella shape opened downward.

As a result, the raw water containing flocs formed by the organic polymer flocculant flows from the inside of the partition wall 13 to the inside of the cylindrical portion 28 of the rotating body 25, and the umbrella-shaped dispersion plate 26 And flows toward the upper side of the baffle plate 27. After that, it collides with the baffle plate 27 arranged on the inner wall of the coagulation sedimentation tank 12 and its periphery, and rebounds. Then, the water is stirred with the rotation of the stirring blades 24a and 24b, and the flock group and the water contained in the flock are squeezed out above the umbrella-shaped dispersing plate 26 and the baffle plate 27, and are compacted. Pellet group is generated,
Here, a dense and stable blanket layer 30 is formed by the dense pellet group.

The raw water containing a large amount of floc settled in the partition wall 13 collides with the umbrella-shaped dispersion plate 26, flows to the side, and further collides with the inner wall of the coagulation sedimentation tank 12 and the baffle plate 27. Further, the mixture is stirred by the rotating stirring plates 24a and 24b. As a result, solid-liquid separation proceeds, and the dense pellets fall downward, and water passes through the blanket layer 30 composed of a group of dense pellets and rises to the upper part of the coagulation sedimentation tank.

As described above, a high-density and stable blanket layer 30 made of dense pellets is formed on the umbrella-shaped dispersion plate 26 and the baffle plate 27. It is filtered while passing through the blanket layer 30 and the supernatant liquid after the filtration is treated water drainage pipe 5
2 to the outside.

That is, at the upper end of the condensation and settling tank 12,
In order to discharge the supernatant liquid accumulated in the upper part of the condensation and sedimentation tank 12 to the outside as treated water, a water discharge gutter 50 and an overflow weir 51 are provided.
Are provided, and a treated water drainage pipe 52 is provided. The supernatant liquid flows into the gutter 50 over the overflow weir 51, and is further discharged from the treated water drain pipe 52 to the outside.
In addition, below the overflow weir 51, a rectifying plate 53 which also serves to hold the partition wall 13 is arranged, rectifies the rising supernatant liquid, and holds and fixes the partition wall 13 in the coagulation sedimentation tank. are doing.

On the other hand, a concentrating unit 40 is provided at the bottom of the coagulation / sedimentation tank 12. That is, the second rotating shaft 2
2 is further extended downward, a raking blade 41 is connected to the lower end, and a bottom plate 42 along the lower surface is arranged below the raking blade 41.

As a result, the concentrated pellets are deposited on the bottom plate 42 at the bottom of the coagulation sedimentation tank 12 by free fall, settled and concentrated, and the concentrated pellets (condensed sludge).
Are stirred along with the rotation of the raking blades 41,
It is rushed to the center. At this time, since the concentrated pellets are supplied from almost the entire surface in the coagulation sedimentation tank, the flow path of the pellets is not blocked by the pellets as in the related art. The bottom plate 42 is connected to a sludge pipe 43 for discharging the concentrated sludge scraped as described above to the outside. The concentrated sludge scraped to the center of the bottom plate 42 is connected to the sludge pipe 43. Is discharged to the outside.

In the above embodiment, the umbrella-shaped dispersion plate disposed substantially in the middle of the coagulation and sedimentation tank and the baffle plate disposed on the inner wall of the tank separates the raw water containing floc that has settled in the partition wall. By dispersing, a dense blanket layer is formed. However, the formation of the blanket layer in the middle part of the coagulation sedimentation tank can be replaced with the one having the same action as the umbrella-shaped dispersion plate and the baffle plate.

[0024]

As described above, according to the present invention, even if the concentration of suspended solids is, for example, raw water having a concentration of 100 ppm or more, it is possible to prevent the flow path of the pellets from being clogged with dense pellets. Thus, the sludge concentration treatment can be reliably performed. In addition, the size and the size can be reduced by using the integral type including the concentration mechanism.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a coagulation and sedimentation apparatus showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a conventional coagulation and sedimentation apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Mixing tank 12 Aggregation sedimentation tank 13 Partition wall 20 Granulation aggregation part 21,22 Rotating shaft 24a, 24b Stirring blade 25 Rotating body 26 Umbrella-shaped dispersion plate 27 Baffle plate 30 Blanket layer 31, 32 Stirring blade 40 Thickening part 41 Scratching Wings 42 bottom plate

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B01D 21/00-21/34

Claims (1)

(57) [Claims] 1. A granulating and aggregating part disposed in an upper part of a sedimentation tank and forming a floc by forming a floc by settling raw water to which a flocculant is added, and a lower opening of the granulating and aggregating part. An umbrella-shaped dispersion plate disposed on the lower side, a baffle plate disposed on the inner wall of the sedimentation tank on the side of the umbrella-shaped dispersion plate, and a concentrated agglomerate disposed and settled at the bottom of the sedimentation tank A coagulation sedimentation apparatus comprising: a concentration mechanism for stirring and further concentrating; and an overflow portion disposed above the sedimentation tank.