CN109661261B

CN109661261B - Coagulation sedimentation device

Info

Publication number: CN109661261B
Application number: CN201780054213.4A
Authority: CN
Inventors: 田中一平
Original assignee: Kurita Water Industries Ltd
Current assignee: Kurita Water Industries Ltd
Priority date: 2016-09-23
Filing date: 2017-03-03
Publication date: 2021-12-24
Anticipated expiration: 2037-03-03
Also published as: CN109661261A; JP2018047434A; KR20190053834A; JP6183525B1; WO2018055794A1; MY195589A; TWI729084B; TW201813703A

Abstract

The invention provides a coagulation sedimentation device which can be easily carried by loading on a truck or the like. Raw water is introduced into an agglutination reaction tank (11), and an inorganic agglutinant, a pH adjusting agent and a cationic polymer agglutinant are added and stirred by a stirrer (15) to form an agglutination reaction solution. The flocculation reaction liquid flows out to a flow transfer plate (17), is fed tangentially into an enlarged diameter part (18A) of a center well (18) after the anionic polymer flocculant is added, and then flows out from a distributor (19) toward the tail stream side in the rotation direction. The treated water having passed through the sludge layer (S) rises in the sedimentation tank (12), flows into the groove (25) from the V-notch (25a), and is taken out of the coagulation sedimentation device (1) through the take-out pipe (26). The sludge is discharged from the sludge receiving tank (13) to the outlet (30) through the rake plate (35).

Description

Coagulation sedimentation device

Technical Field

The present invention relates to a coagulation-sedimentation device for coagulating and separating fine suspended matter and the like from water to be treated.

Background

It is known that solid-liquid separation is performed by adding an inorganic flocculant to raw water (water to be treated) such as factory drainage or sewage and then adding an anionic polymer flocculant and a cationic polymer flocculant. Patent document 1 discloses a water treatment apparatus including: an in-line mixing device for adding an inorganic coagulant, a cationic polymer coagulant, and an anionic polymer coagulant to fine SS-containing raw water; and a granulation-type coagulation-precipitation tank provided downstream of the line mixer.

Patent document 2 describes a coagulation-sedimentation device in which a first stirring tank to which an inorganic coagulant is added and stirred, a second stirring tank to which a sedimentation accelerator and a polymer coagulant are added and stirred, a third stirring tank to which a polymer coagulant is added and stirred, a flocculation tank and a sedimentation tank are integrated.

Patent document 1: international publication No. 2014/038537;

patent document 2: japanese patent laid-open No. 2014-.

Disclosure of Invention

The invention aims to provide a coagulation sedimentation device which can be easily carried in a mode of loading on a truck or the like.

The coagulation sedimentation device of the present invention comprises: a tank body in a rectangular shape in plan view; the agglutination reaction tank and the sedimentation tank formed in the tank body are separated by a partition plate; and a sludge receiving tank adjacent to the settling tank with an overflow plate for sludge interposed therebetween. The tank body has a width of 2.2m or less, a length of 5.6m or less, and a height of 2.6m or less.

In the coagulation-sedimentation device according to one embodiment of the present invention, a center well is provided in the sedimentation tank, and a transfer member for causing the coagulation-flocculation solution in the coagulation-flocculation tank to flow into the center well is provided.

In the coagulation sedimentation device according to one aspect of the present invention, the distributor is provided to extend radially from a lower portion of the center well, and the driving device is provided to drive the center well to rotate around the axis.

In the coagulation sedimentation device according to one embodiment of the present invention, a sludge discharge port for discharging the sludge in the sludge receiving tank is provided in a wall surface of the tank body, and a rake plate is provided to move toward the sludge discharge port along a bottom surface in the sludge receiving tank.

In the coagulation sedimentation device according to the aspect of the present invention, the rake plate is attached to an endless drive chain that is stretched between a drive-side sprocket and a driven-side sprocket so as to have a forward side along the bottom surface of the sludge receiving tank and a reverse side arranged above the forward side, and when the rake plate is reversed by the chain, the upper end of the rake plate is positioned below the upper edge of the overflow plate.

[ Effect of the invention ]

The tank body of the coagulation sedimentation device of the present invention has a size that allows it to be loaded on a 4t truck (a truck having a maximum load of 4 t), and is rectangular in plan view, so that it is easy to carry. Further, since the mixer, the center well, the distributor, and other accessories are integrated in advance in the manufacturing plant of the coagulation-sedimentation device, the installation work of the coagulation-sedimentation device is significantly easier.

By providing the rake device in the sludge receiving tank, the precipitated sludge can be smoothly taken out from the sludge take-out port. The rake device is provided with a rake plate that moves along the bottom surface of the sludge receiving tank, and thereby sludge can be scraped to the outlet side from almost the entire area of the bottom surface in the sludge receiving tank. In the case where the rake plate is configured to advance toward the outlet along the bottom surface of the sludge receiving tank and move in an inverted manner from the chain on the return side of the chain, the upper edge of the rake plate at the time of return is located below the upper edge of the overflow plate, and therefore the sludge layer in the settling tank is not disturbed.

Drawings

FIG. 1 is a perspective view of a tank body of a coagulation-sedimentation device according to an embodiment.

FIG. 2 is a plan view of the coagulation sedimentation device according to the embodiment.

Fig. 3 is a sectional view taken along line III-III of fig. 2.

Fig. 4 is a sectional view taken along line IV-IV of fig. 2.

FIG. 5 is a plan view of another embodiment of the coagulation sedimentation device.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings. FIGS. 1 to 4 show a coagulation-sedimentation device 1 according to a first embodiment of the present invention.

The coagulation-sedimentation device 1 includes: a tank body 2 having a pair of

short side walls

2a and 2c and a pair of

long side walls

2b and 2d and having a rectangular shape in plan view (a rectangular shape as a whole); partition plates 3, 4 provided in the short side direction (width direction) in the tank body 2; and an overflow plate 5 provided between the partition plate 4 and the short side wall 2c of the tank body 2 along the longitudinal direction of the tank body 2. The tank body 2 has a width of 2.2m or less, a length of 5.6m or less, and a height of 2.6m or less so that it can be loaded on a 4-t truck. The width of the tank body 2 is preferably 1.0 to 2.2m, especially 1.5 to 2.2 m. The length of the tank body 2 is preferably 1.0-5.6 m, especially 1.5-5.6 m. The height of the tank body 2 is preferably 1.0-2.6 m, especially 1.5-2.6 m.

The partition plates 3 and 4 are erected from the bottom surface 2e of the tank body 2 to the vicinity of the upper edge of the tank body 2. The partition plates 3 and 4 are connected to the

long side walls

2b and 2d of the tank body 2. A machine chamber 10 is formed between the partition plate 3 and the short side wall 2a of the tank body 2 so as to arrange a control panel, a pump and other machines.

A flocculation tank 11 is provided between the partition plates 3 and 4, and a sedimentation tank 12 and a sludge receiving tank 13 are provided between the partition plate 4 and the short side wall 2c of the tank body 2. The sedimentation tank 12 and the sludge receiving tank 13 are separated by the overflow plate 5. Volume V of the flocculation tank 11₁Volume V of the settling tank 12₂Ratio V of₁/V₂Preferably about 0.9 to 1.2.

The flocculation tank 11 may be provided with a stirrer 15 for stirring the liquid in the tank while adding an inorganic flocculant and a cationic polymer flocculant via a chemical injection device (not shown).

An outlet 16 for the agglutination reaction liquid is provided at the upper part of the partition plate 4, and a transfer plate (or piping) 17 as a transfer member is connected to the upper part of the partition plate 4 so as to be connected to the outlet 16. The flow-transferring tray 17 is provided with a chemical injection device (not shown) for adding an anionic polymer flocculant.

Preferably, the settling tank 12 is formed in a substantially square shape in plan view. A center well 18 is provided in the center of the settling tank 12. The center well 18 is cylindrical and has an enlarged diameter portion 18A at the upper portion. The front end of the flow-transferring plate 17 is disposed so that the flocculation reaction solution flows out in a substantially tangential direction in the enlarged diameter portion 18A.

The lower part of the central well 18 is provided with a distributor 19. The distributor 19 is formed of a tubular body extending radially from the center well 18, and has an outlet 19a on the wake side in the rotation direction. The rake 19b is provided on the distributor 19 so as to face downward, but may be omitted.

The center well 18 is supported on the tank bottom surface 2e by a shaft support portion 20 and is rotatable around the shaft center.

The upper portion of the center well 18 is connected to a rotary shaft 22a of a driving device 22 via a bracket 21. An agitating blade 23 is attached near the middle of the center well 18 in the vertical direction.

The upper part of the inside of the precipitation tank 12 is provided with a groove 25 for taking out supernatant (treated water). The vertical cross-sectional shape of the groove 25 is U-shaped, and the supernatant in the sedimentation tank 12 is made to flow into the groove 25 through a V-notch 25a provided at the upper edge.

The groove 25 is formed in a frame shape so as to surround the center well 18. The groove 25 extends along the long side wall 2b and the short side wall 2c of the tank body 2 and the partition plate 4 with a predetermined space therebetween. In these portions, V notches 25a are provided only on the side of the center well 18 (inside the surrounding frame) at the upper edge of the groove 25.

The groove 25 extends in the longitudinal direction of the tank body 2 above the overflow plate 5 on the side of the center well 18. In this portion, V notches 25a are provided on both sides of the upper edge of the groove 25, i.e., on the side of the center well 18 (inside the enclosure frame) and on the side of the sludge receiving tank 13 (outside the enclosure frame).

A treated water extraction pipe 26 is connected to the groove 25. The V-notch 25a of the groove 25 is at the level of the liquid level in the precipitation tank 12. In the present embodiment, the diameter-enlarged portion 18A is located above the liquid surface level. However, the enlarged diameter portion 18A may be disposed in contact with the liquid surface.

An inclined plate 28 is provided at the bottom of the settling tank 12 so as to be inclined downward toward the center of the settling tank 12 at the corner of intersection between the long side wall 2b and the short side wall 2c of the tank 2 and the bottom 2e of the tank 2 and at the corner of intersection between the lower part of the partition plate 4 and the overflow plate 5 and the bottom 2e of the tank 2, and the inclined plate 28 is configured to eliminate the stagnation area of the liquid or sludge.

The overflow plate 5 has a height from the bottom surface 2e to a height of about 50 to 80% of the height of the liquid surface in the settling tank 12. A sludge layer S is formed in the sedimentation tank 12 up to the level of the upper edge of the overflow plate 5.

The amount of the sludge blanket S formed in the settling tank 12 increases with the treatment, but if the level (sludge interface) of the sludge blanket S exceeds the height of the overflow plate 5, the sludge (sludge) in the sludge blanket S overflows the overflow plate 5 and falls into the sludge receiving tank 13. An inclined plate 29 is provided on the bottom surface in the sludge receiving tank 13. The inclined plate 29 is provided so as to be inclined downward from the long side wall 2d toward the overflow plate 5.

As shown in fig. 1, a sludge outlet 30 for taking out sludge (sludge) in the sludge receiving tank 13 is provided at a lower portion of the short side wall 2 c. A rake device 31 for moving sludge (sludge agglomerates) toward the sludge outlet 30 is provided in the sludge receiving tank 13.

The rake device 31 includes: a driving side sprocket 32 and a driven side sprocket 33 provided on the overflow plate 5 and the long side wall 2d, respectively; an endless rotating chain 34 bridged between the

sprockets

32, 33; a harrow plate 35 spanning between the

chains

34, 34 and fixed to each chain 34; and a driving device 36 for driving the driving-side sprocket 32. Preferably, more than 2 rake plates 35 are provided.

The rake plate 35 moves (advances) from the partition plate 4 side toward the sludge outlet 30 side along the inclined plate 29, whereby the bottom sludge (sludge) in the sludge receiving tank 13 is scraped close to the sludge outlet 30.

When the rake plate 35 advances from the partition plate 4 side toward the take-out port 30 side, the rake plate 35 is in a posture of hanging down from the chain 34. When the harrow plate 35 is reversed from the take-out port 30 toward the side of the partition plate 4, the harrow plate 35 is in a state of being erected from the chain 34. Preferably, the upper end of the rake plate 35 in the erected state is located at a position lower than the upper edge of the overflow plate 5 by 50cm or more. The lower edge of the rake plate 35 in the hanging state has an angle along the surface of the inclined plate 29.

In the coagulation-sedimentation device 1 configured as described above, raw water is introduced into the coagulation-flocculation tank 11 through a pipe (not shown), and an inorganic coagulant, a pH adjuster, and a cationic polymer coagulant are further added thereto and stirred by the stirrer 15 to form a coagulation-flocculation solution.

The flocculation reaction liquid flows out to the flow-shifting tray 17, the anionic polymer flocculant is added, and then, the liquid is fed tangentially into the enlarged diameter portion 18A of the center well 18, flows into the center well 18 while swirling inside the enlarged diameter portion 18A, flows downward into the center well 18, flows to the distributor 19, and flows out from the outlet 19a toward the tail stream side in the rotation direction of the distributor 19.

Further, if the water supply well 18 does not have the enlarged diameter portion 18A and the coagulation treatment liquid is directly introduced into the water supply well 18, air in the atmosphere may be entrained in the coagulation treatment liquid, and air bubbles may be mixed into the precipitation tank 12. In the present invention, since the settling tank 12 is relatively small, the sludge in the sludge blanket S may be greatly rolled up even if only a little air bubbles are mixed. Therefore, by providing the enlarged diameter portion 18A in the water feed well 18, the coagulation treatment liquid flows into the enlarged diameter portion 18A in the tangential direction and swirls, and during this time, air bubbles are released from the coagulation treatment liquid into the atmosphere, thereby preventing the air bubbles from being mixed into the water feed well 18.

The distributor 19 and the stirring blade 23 are rotated slowly by the driving device 22, and the inside of the settling tank 12 is stirred slowly, thereby promoting the generation and growth of the flocculated flocs and the sludge (agglomerates) in the sludge blanket S and producing a stable sludge blanket S. Preferably, the rotation speed of the distributor 19 is about 0.6 to 1.4 rpm.

While the coagulation-flocculation reaction liquid passes through the sludge blanket S, the coagulated flocs are fixed to the sludge (agglomerates) in the sludge blanket and form clarified treated water. The clarified treated water having passed through the sludge blanket S rises from the sedimentation tank 12, flows into the groove 25 through the V-notch 25a, and is taken out of the coagulation sedimentation device 1 through the take-out pipe 26.

In the present embodiment, the groove 25 located on the overflow plate 5 side is provided with the V notch 25a on both sides of the center side of the sedimentation tank 12 and the sludge receiving tank 13 side, and the groove 25 located on the other side than the overflow plate 5 side is provided with the V notch 25a only on the center side of the sedimentation tank 12. Based on this, the upward flow LV in the precipitation tank 12 can be set large. That is, by providing a V-notch on the sludge receiving tank 13 side of the groove on the overflow plate 5 side, a part of the liquid in the sedimentation tank 12 flows toward the sludge receiving tank 13 to form an upward flow, and is discharged as treated water from the V-notch. Based on this, the upward flow LV in the vicinity of the trench 25 is slightly smaller than the upward flow LV in the precipitation tank 12, and the treated water having stable quality can be easily obtained.

In the present embodiment, since the entire enlarged diameter portion 18A of the center well 18 is disposed above the water surface in the settling tank 12, the upward flow LV in the settling tank 12 can be set larger than in the case where the lower portion of the enlarged diameter portion 18A is disposed below the water surface. In this embodiment, the upward flow LV in the precipitation tank 12 can be set to about 5 to 20m/hr, particularly about 8 to 15 m/hr.

If the interfacial height of the sludge (sludge agglomerates) in the sludge layer S is higher than that of the overflow plate 5, the sludge (agglomerates) overflows the overflow plate 5, flows into the sludge receiving tank 13, and settles to the bottom of the sludge receiving tank 13. The sludge (sludge) is scraped by the scraper 35 toward the outlet 30, and is taken out of the coagulation sedimentation device 1 from the outlet 30 via a take-out pipe and a sludge pump (not shown). The on/off of the sludge pump is controlled by an interfacial meter or a timer for detecting the height of the sludge interface in the sludge receiving tank 13.

The tank body 2 of the coagulation-sedimentation device 1 has a size capable of being loaded on a 4t truck, and is rectangular in a plan view, so that it is easy to carry. Further, the installation work of the coagulation-sedimentation device 1 is significantly facilitated by integrating a stirrer, a center well, a distributor, and other accessories in a manufacturing plant.

The sludge receiving tank 13 is provided with a rake 31, and the settled sludge (sludge) is smoothly taken out from the sludge take-out port 30. The rake device 31 includes a rake plate 35 that moves along the inclined plate 29, and can scrape sludge (dough-like material) from almost the entire area of the bottom surface in the sludge receiving tank 13 toward the discharge port 30. The rake plate 35 advances along the inclined plate 29 toward the take-out opening 30, and moves upright from the

chains

34, 34 on the reverse side of the chain 34. In this return operation, the upper edge of the rake plate 35 passes through a position sufficiently lower than the upper edge of the overflow plate 5, and therefore the sludge layer S in the settling tank 12 is not disturbed.

In the above embodiment, the sedimentation tank 12 and the sludge receiving tank 13 are disposed adjacent to each other in the short side direction of the tank body 2, but as shown in the coagulation-sedimentation device 1' of fig. 5, the sludge receiving tank 13 may be disposed on the short side wall 2c side of the sedimentation tank 12. The other structures of the coagulation-sedimentation device 1' of FIG. 5 are the same as those of the coagulation-sedimentation devices of FIGS. 1 to 4, and the same reference numerals denote the same parts.

The coagulation-sedimentation devices 1 and 1' according to the above embodiments have the integrated tank body 2 partitioned by the partition plates 3 and 4 and the overflow plate 5, but for example, the mechanical chamber 10, the flocculation tank 11 and the sedimentation tank 12 may be separately manufactured, and the separate chambers and tanks may be connected to each other to constitute the integrated tank body 2. At this time, the partition 3 is held between the wall surfaces of the machine chamber 10 and the flocculation tank 11, and the partition 4 is held between the wall surfaces of the flocculation tank 11 and the sedimentation tank 12.

[ coagulant ]

The inorganic coagulant is preferably PAC, polyferric (polymeric ferric sulfate), ferric chloride (ferric trichloride), aluminum sulfate, or the like, which can form a hydroxide. In the fluorine-containing water or phosphoric acid-containing water, a calcium compound such as slaked lime may be used as the inorganic coagulant. Preferably, the amount of the inorganic coagulant to be added is 20 to 2000mg/L, particularly about 50 to 1500 mg/L.

The cationic polymer (cationic polymer coagulant) is preferably an acrylamide polymer, and the cationic group ratio thereof is preferably 10 to 50 mol%, particularly 15 to 40 mol%, and more preferably 15 to 30 mol%. The cationic polymer flocculant has a weight average molecular weight of 1200 to 2500 ten thousand, preferably about 1500 to 2200 ten thousand. The amount of the cationic polymer coagulant to be added is 0.1 to 3mg/L, and particularly preferably 0.5 to 2 mg/L.

As such a cationic polymer, for example, a copolymer of a cationic monomer and acrylamide can be preferably used. Specific examples of the cationic monomer include, but are not limited to, acid salts of dimethylaminoethyl acrylate or methacrylate (hereinafter, both compounds may be referred to as "dimethylaminoethyl (meth) acrylate") or 4-stage ammonium salts thereof, acid salts of dimethylaminopropyl acrylamide or dimethylaminopropyl methacrylamide (hereinafter, both compounds may be referred to as "dimethylaminopropyl (meth) acrylamide") or 4-stage ammonium salts thereof.

The product form of the cationic polymer is not particularly limited, and products generally circulated in the coagulation treatment of drainage, such as a powder product, a W/O emulsion, or a dispersion in which cationic polymer coagulant particles are dispersed in an aqueous medium having a high salt concentration, can be used.

The anionic polymer (anionic polymer coagulant) is preferably an acrylamide polymer, and the proportion of anionic groups is preferably 5 to 30 mol%, particularly preferably 5 to 20 mol%. The weight average molecular weight of the anionic polymer is from 900 to 2000 ten thousand, and particularly preferably from 1000 to 1800 ten thousand. The amount of the anionic polymer flocculant to be added is 0.2 to 8mg/L, and particularly preferably 0.5 to 6 mg/L.

As such an anionic polymer, for example, a copolymer of an anionic monomer and acrylamide, or a hydrolysate of polyacrylamide can be used. As a specific example of the anionic monomer, acrylic acid or a salt thereof can be preferably used. As the anionic monomer, acrylic acid or a salt thereof, and a polymer obtained by copolymerizing 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof with acrylamide are particularly preferably used because it can be stably used in a wide pH range.

All the embodiments described above are merely examples of the present invention, and the present invention may be other than those illustrated in the drawings.

This application is based on Japanese patent application 2016-.

Description of the symbols

1. 1': and (4) an agglutination and precipitation device.

2: a tank body.

3. 4: a separator.

5: an overflow plate.

10: and a mechanical chamber.

11: an agglutination reaction tank.

12: a settling tank.

13: sludge receiving tank.

15: a blender.

17: and a flow moving disc.

18: a central well.

18A: an expanding portion.

19: a distributor.

23: a stirring blade.

25: and (4) a groove.

Claims

1. A coagulation-sedimentation device, wherein,

the coagulation sedimentation device is provided with a groove body,

the tank body is rectangular in plan view and the whole tank body is cuboid,

the tank body is provided with a coagulation reaction tank and a sedimentation tank which are formed by separating the tank body by a clapboard, and a sludge receiving tank which is adjacent to the sedimentation tank by an overflow plate separating sludge,

the coagulation-sedimentation device further comprises a stirrer provided in the coagulation-sedimentation tank and an attachment attached to the tank,

the width of the groove body is less than 2.2m, the length is less than 5.6m, the height is less than 2.6m,

a sludge outlet for taking out the sludge in the sludge receiving tank is arranged on the wall surface of the tank body,

a center well is provided in the settling tank, and a transfer means for allowing the flocculation reaction solution in the flocculation reaction tank to flow into the center well is provided,

a distributor is arranged at the lower part of the central well,

an enlarged diameter part is provided above the center well, and the entire enlarged diameter part is arranged above the water surface,

the coagulation sedimentation device is a device in which a tank body, a stirrer, a center well, a distributor, and accessories are integrated in advance.

2. A coagulation sedimentation device according to claim 1,

a rake plate is provided to move along the bottom surface in the sludge receiving tank toward the sludge outlet.

3. An agglutination and precipitation device according to claim 2,

the rake plates are mounted on an endless driven chain,

the chain is arranged between the driving side chain wheel and the driven side chain wheel in a mode of having an advancing side along the bottom surface of the sludge receiving groove and a reverse side arranged above the advancing side,

when the harrow plate is reversed by the chain, the upper end of the harrow plate is positioned lower than the upper edge of the overflow plate.