JP2003265905A - Flocculating and settling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flocculating and settling apparatus which can continuously be operated stably over a long time at a small injection rate of a chemical even when raw water having high turbidity is treated. <P>SOLUTION: Conical bodies (4...) each having many through-holes (3...) are arranged vertically in a filtration tank (1) at several stages. A circular body (5) is fixed to each of the bodies (4b, 4c) arranged in the upper part of the bottom end of the tank (1). The lowermost body (4a) is inserted into the lowermost body (5) to form a gap (7) between the bodies (4a) and (5). A precipitate flow passage (8) is formed between the inner peripheral wall of the tank (1) and the body (5). A filter medium layer (12) to be packed with a floatable packing material (10) consisting of a flat, short and cylindrical filter medium is formed in the upper part of the bodies (4...). Flocks in raw water are grown by the slow agitation action generated when an upward stream of the raw water passes through the through-holes (3...), made to fall down through the passage (8) without being affected by the upward stream of the raw water, precipitated and concentrated. The material (10) which captures flocks and is settling down is swayed by the rising water current so that the captured flocks are peeled off and dropped out and the flock-free material (10) is made to float in the layer (12). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flocculation in which an inorganic or organic flocculant is added to a stock solution such as river water, rainwater or industrial wastewater to flocculate and precipitate fine suspended substances contained in the raw water. Regarding precipitation equipment.

[0002]

2. Description of the Related Art Conventionally, a flocculation-sedimentation device for precipitating and separating flocculation flocs in raw water by means of separation plates arranged in multiple stages is well known. For example, as described in JP-A-5-200205, A settling device in which a parallelogram-width inclined plate is arranged on the plate is also known. In addition, a large number of slant plates and a levitation filter material filling section above the slant plate were installed in the settling tank to suspend suspensions with a large particle size on the slant plate, and suspensions with a small particle size were used as floating filter media. An apparatus for blowing air from an air introduction pipe to flow and agitate the filter medium when the floatable filter medium is clogged after removal is also known, for example, as described in JP-A-7-80210.

[0003]

The conventional inclined plate described above is capable of separating agglomerated heavy flocs, but light fine flocs have been mixed into the separated water after passing through the inclined plate. If these treated waters are subjected to secondary treatment with a sand filter device or a floating filter medium device, sudden clogging occurs and it is necessary to wash them frequently. Further, in a device in which a suspension having a large particle size is settled on an inclined plate and a suspension having a small particle size is removed by a floating filter, it is a process by a contact precipitation action, and is processed at a high speed. In this case, a breakthrough phenomenon is likely to occur and there is a risk that the turbidity removal rate may decrease. Then, in the device for passing the raw water flowing in from the conventional tank wall in the upward flow, the precipitation concentration zone is below the raw water inflow position, and the upward flow of fine suspended substances in the raw water. However, it interfered with the sedimentation of the coarse flocculated flocs, which hindered the sedimentation separation. In order to solve the above-mentioned conventional problems, the present invention enables stable continuous operation for a long time with a low chemical injection rate even in high turbidity raw water, and has a large treatment speed and a flocculating function having a turbidity removing function. Provide a device.

[0004]

Means for Solving the Problems The gist of a flocculating and precipitating apparatus according to the present invention is to supply a stock solution to a filtration tank in an upward flow, and to separate suspended particles by separating plates arranged in multiple stages. The conical body provided with a large number of through holes in the filtration tank is vertically suspended in a plurality of stages, the circular body is fixed to the conical body above the lower end portion, and the lower conical body is inserted into the upper circular body. , A gap is provided between the torus and the conical body, a precipitation flow path is formed between the inner wall of the filtration tank and the torus, and the feed port for the undiluted solution is arranged near the lower end of the conical body. The raw water causes flocs to grow due to turbulent flow when passing through the conical hole of the cone, and the grown flocs slide down the slope of the cone and are affected by the upward flow of the raw water. Without precipitation from the precipitation channel.

A cylindrical body is disposed in the vicinity of an annular body fixed to the cone at the upper end, and the upper half of the cone is inserted into the cylindrical body. The fine flocs are rectified by the cylindrical body, and the fine flocs having a large specific gravity slide down on the slope of the conical portion of the conical body and settle out from the settling channel, so that the fine flocs can be separated. And
A filter material layer is formed by storing a levitation filler having a large porosity in a filtration tank, and the levitation filler is randomly laminated using short tubular filter media having a large porosity and no irregularities,
A stagnation portion for the upward flow is formed, and fine flocs are deposited to bond the flocs to each other, and the grown flocs are separated by sedimentation. Also, the floating material that has captured many flocs falls, and while it is settling, it swings due to the water flow rising from the through hole of the conical body, and the flocs that have captured are separated and fallen off, and a new floating surface is washed again. As a filler, the fine flocs can be captured by floating on the filter layer.
It enables stable continuous operation for a long time with a small chemical injection rate, and can exhibit a large processing speed and turbidity.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The flocculation-sedimentation apparatus according to the present invention is configured as described above, and a small amount of flocculant and neutralizing agent are added to raw water so that the raw water is fed from the feed port to the vicinity of the lower part of the cone. Allow upflow. Raw water containing agglomerated flocs flows into the vertically downward conical body, and heavy flocs settle on the bottom of the filtration tank along the inner peripheral wall of the torus due to the circulating flow. In the raw water that rises after passing through the cone at the lower end, flocs grow due to turbulent flow until it passes through the holes in the cone at the upper part. Slide down the slope of the cone of the cone without passing through. It is concentrated from the settling channel without being affected by the upward flow of raw water.

While repeating the above operation, flocs grow and precipitate due to the slow stirring action due to the disturbance of the water flow generated between the upward flow and the through hole of the conical body. The flocs in the raw water that pass through the cone gradually become fine particles, and the fine flocs that could not grow up after passing through the vertically placed cone are
It flows into the levitation filler that is rectified by the cylindrical body and forms the filter layer, and the short tubular filter that has no irregularities forms a stagnation part against the upward flow, which causes the fine flocs contained in the raw water to settle and Flocks grow together. Floating fillers that have captured many flocs settle because the specific gravity becomes heavier than water, but the floating fillers rock while they settle, and the flocs that have been trapped peel off and are washed off. As a result, the fine flocs are captured again by floating on the filter layer. The treated water from which fine flocs have been separated by the filter layer of the floating filler is drawn out from the upper part of the filtration tank. Then, the flocs having a large specific gravity that have settled down settle in the concentration chamber to become settled concentrated sludge, and the concentrated sludge is appropriately extracted from the bottom of the filtration tank.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The coagulation-sedimentation apparatus according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows a coagulation-sedimentation apparatus in which a raw water supply pipe 2 is connected to a lower portion of a filtration tank 1 formed in a cylindrical shape. The supply port 2a is opened at the center of the filtration tank 1, and raw water added with a small amount of a coagulant and a neutralizing agent is supplied to the supply port 2a.
It is made to flow upward from a. FIG. 2 is an enlarged view of a conical body vertically installed in a filtration tank. A conical body 4 having a large number of through holes 3 ... In the embodiment of the present invention, it is vertically provided in three stages, and the annular bodies 5, 5 are fixed to the lower ends of the upper two stages of cones 4b, 4c. The upper half of the lower cone 4 is inserted into the upper annular body 5, and the lower cones 4 a, 4
The lower end of b and the lower ends of the upper annular members 5 and 5 are connected to one ends of vertically extending flat plate-shaped ribs 6, 6 and a gap 7 is provided between the annular member 5 and the conical member 4. . As shown in FIG. 3, the other end of the rib 6 is fixed to the inner peripheral surface of the filtration tank 1 to form a precipitation channel 8 between the inner peripheral wall of the filtration tank 1 and the annular body 5. .

The suspended matter in the raw water grows due to turbulent flow when passing through a large number of through holes 3 in the lower cone 4a, and the heavy flocs that grow grow through the holes in the upper cone 4b. Without passing through No. 3, it slides down from the slope of the cone 4a and flows into the settling channel 8, and the settling channel 8 is settled without being affected by the upward flow of raw water. The raw water passing through the through holes 3 of the upper cone 4b has an upward flow and the through holes 3 of the cone 4b.
The flocs grow and precipitate due to the slow stirring action due to the disturbance of the water flow generated between the and. The flocs in the raw water passing through the vertically-arranged conical body 4c are separated and gradually become fine particles, and the above operation is repeated.

As shown in FIG. 1, a cylinder 9 is disposed above the annular body 5 at the upper end, and the lower end of the cylinder 9 and the lower end of the cone 4c are connected to one end of the rib 6. There is. The upper half of the cone 4c at the upper end is inserted into the cylindrical body 9 to
There is a gap 7 between the and the cone 4c. The other end of the rib 6 is fixed to the inner peripheral surface of the filtration tank 1 to form a precipitation channel 8 between the filtration tank 1 and the cylindrical body 9. The fine flocs that have passed through the upper conical body 4c are rectified by the cylindrical body 9 to separate fine flocs having a large specific gravity. The aggregated flocs reaching the cylindrical body 9 are very small because many suspended substances are separated by the cones 4a, 4b, 4c arranged in a plurality of stages, and the amount of the aggregating agent added may be small.

As shown in FIG. 1, floating fillers 10 ... Are accommodated above a cylindrical body 9 arranged in the filtration tank 1, and an upper filter medium outflow prevention net 11 stretched above the filtration tank 1 is provided. The filter medium layer 12 is formed below. The floating filler 10 is formed by randomly stacking short tubular filter media having a large porosity and no irregularities. Reference numeral 19 is a lower filter medium outflow prevention mesh provided below the filter medium layer 12. The fine flocs contained in the raw water flow into the filter medium layer 12 and rise. Fine flocs are deposited to combine the flocs with each other, and some of the grown flocs are dropped. Further, the floating fillers 10 ... Capturing a large amount of flocs fall because the specific gravity becomes heavier than water.
While the floating filler 10 is settling, the flocs captured by rocking due to the water flow rising from the through hole 3 of the cone 4 are separated and dropped off, and returned to the filter medium layer 12 as a new washed floating filler 10 again. Captures fine flocs. Since the flocculant is added in a small amount, flocculation flocs become flocs with low stickiness and excellent releasability, and since the floating filler 10 with few irregularities is used, the flocs that have precipitated can be easily peeled off. it can. Since the floating filler 10 has a large porosity, it can be continuously operated for a long time.

A sedimentation / concentration unit 13 in which the bottom of the filtration tank 1 has an inverted conical shape is provided, and the grown flocs are sedimented from the sedimentation flow path 8 to be concentrated and stored. put out. A treated water chamber 16 connected to the treated water pipe 15 is provided above the filtration tank 1, and the treated water that has passed through the filter medium layer 12 is discharged from the treated water pipe 15. In addition, the cleaning of the filtration layer 12 having a reduced processing capacity is performed by the filtration tank 1 below the filter material layer 12.
After draining the water from the washing drainage pipe 17 connected to the vicinity of the cylindrical body 9, the washing water pipe 18 disposed in the treated water chamber 16 sprays the washing water to the filter medium layer 12 to shower the water. The filling material 10 can be washed.

[0013]

As described above, the coagulation-sedimentation apparatus of the present invention is a combination of a separation device consisting of conical bodies suspended in multiple stages in a filtration tank and a filtration layer composed of a floating filler, so that the chemical injection rate is low. Enables stable continuous operation for a long time,
High processing speed and turbidity can be demonstrated. That is, in the conventional coagulation-sedimentation treatment of highly turbid raw water, it is necessary to wash it frequently, and a breakthrough phenomenon is likely to occur, and there is a possibility that the turbidity may be deteriorated. Further, the fine suspended matter in the raw water hinders the sedimentation and separation of the coarse flocculated flocs. In the present invention, a plurality of cones having a large number of through holes are provided. Vertically installed in a step, insert the lower conical body into the conical body to which the upper circular body is fixed, and provide a gap between the circular body and the conical body to form the inner wall of the filtration tank and the circular body. Since a settling flow path was formed between the two, the raw water passing through the through hole of the conical body grows flocs by the slow stirring action due to the disturbance of the water flow generated between the upward flow and the through hole of the conical body. , Slide down the slope of the cone,
The sediment can be concentrated by flowing down from the sedimentation channel without being affected by the upward flow of raw water.

A cylindrical body is disposed in the vicinity of an annular body fixed to the cone at the upper end portion, and the upper half of the cone is inserted into this cylindrical body. The fine flocs are rectified in the cylinder to separate the fine flocs having a high specific gravity, the aggregate flocs reaching the cylinder are very small, and the amount of the flocculant added is also small. In addition, since the filter material layer was formed by storing the floating filler with a large porosity in the filtration tank, a stagnation part was formed against the upward flow, and fine flocs were deposited and the flocs were bonded to each other to cause sedimentation separation. it can. Since the floating filler is a short tubular filter medium with no irregularities, the floating filler that has captured the flocs is shaken by the rising water flow while it is settling, the flocs are peeled off, and floated again on the filter layer. As a result, fine flocs can be captured.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view of a coagulating sedimentation apparatus according to the present invention.

FIG. 2 is likewise a side sectional view of a conical body vertically provided in the filtration tank.

FIG. 3 is likewise a plan view of a conical body vertically provided in a filtration tank.

[Explanation of symbols]

1 filtration tank 2a Supply port 3 through holes 4, 4a, 4b, 4c cone 5 torus 7 Gap 8 sedimentation channels 9 cylindrical body 10 Floating filler 12 Filter media layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01D 29/08 540A

Claims (4)

[Claims] 1. An undiluted solution is supplied to the filtration tank (1) in an upward flow,
In a settling device for separating suspended particles by separating plates arranged in multiple stages, a conical body (4) provided with a large number of through holes (3 ...) Is vertically installed in a plurality of stages in the filtration tank (1), and a lower stage is provided. Cone (4
The annular body (5) is fixed to the upper conical body (4b, 4c) of a) and inserted into the upper annular body (5) of the lower end portion so that the conical body (5) and the conical body (4) ) Between the inner wall of the filtration tank (1) and the torus (5) to form a settling channel (8), and the lower end of the conical body (4a). A coagulating sedimentation apparatus, characterized in that a supply port (2a) for the undiluted solution is arranged near the lower part. 2. A cylindrical body (9) is arranged in the vicinity of the upper side of the annular body (5) fixed to the conical body (4c) at the upper end,
The coagulating sedimentation apparatus according to claim 1, wherein the upper half of the conical body (4c) is inserted into the cylindrical body (9). 3. The floating filler (10) in the filtration tank (1).
The coagulating sedimentation apparatus according to claim 1 or 2, characterized in that the filter medium layer (12) is housed therein. 4. The floating filler (10) is characterized in that short tubular filter media having a large porosity and no irregularities are randomly laminated to form a filter media layer (12). The described coagulating sedimentation device.