JP2000271407A - Flocculating and settling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flocculating and settling device obtaining excellent water quality of treated water with a small installation area. SOLUTION: A tank 2 in which water to be treated adding sand and a flocculating agent is rapidly stirred to produce aggregates, a flock forming tank 6 in which the aggregates are slowly stirred to allow to grow them to flocks, and a settling tank 7 partitioned with the flock forming tank 6 and an overflow wall 8, in which the flocks contained in overflowing and moving water are precipitated and discharged with a pump, are provided in the device. In the flock forming tank 6, a flock fluidizing region A in which the flocks are fluidized in the vertical directions with an agitation flow, is formed at the bottom of the tank, and a horizontal cross-sectional area at the upper part is made larger, thus a clear region B in which a flock fluidization due to the above mentioned agitation flow is substantially not affected, is formed, and an overflow trough is provided on the upper part of the clear region B, and the upper end of the overflow wall is positioned at the lower side than the upper limit of the flock fluidizing region A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for coagulating and precipitating a suspension (SS) in water to be treated.
The present invention relates to a coagulation sedimentation apparatus for removing SS, which is capable of efficiently performing coagulation sedimentation treatment at a high sedimentation rate by adding sand to water to be treated.

[0002]

2. Description of the Related Art As a coagulation-sedimentation apparatus for removing fine organic and inorganic suspensions (SS), sand is used as a method for rapidly sedimenting and separating sediment by coagulating SS in water to be treated and further growing flocs. Japanese Patent No. 2634230 discloses a method of adding an insoluble particulate matter (hereinafter collectively referred to as "sand") and a coagulant to water to be treated to form SS aggregates and grow flocs in a suspended state of sand. Gazette, JP-A-8
-47606.

In this method, the specific gravity of floc to be settled and separated by the coagulation sedimentation method is generally about 1.01 to 1.02, and the sedimentation speed is low. The floc can be given a large sedimentation velocity by containing the flocculant. For example, as shown in FIG. (Inorganic flocculant and polymer flocculant) and sand are added, and a rapid stirring tank 41 is formed to form a coagulated product of the sand and the suspension with rapid stirring. A slow stirring tank 42 in which small aggregates are grown into large flocs while slowly stirring, and water to be treated is transferred from the slow stirring tank 42 by an overflow method to precipitate flocs having a large sedimentation velocity including sand. And tilt It is carried out by configured flocculator device to comprise a settling tank 43 for discharging the clear treated water separated floc from the top through the rectifying means such as a leaf 44 to the outside. The floc (sludge) settled and separated from the treated water in the sedimentation tank 43 is drawn out of the tank by a sludge drawing pump 45 and sent to a cyclone 46, where SS and sand in the combined sludge are separated, and the sand is separated. The sand is reused as sand to be added to the coagulation tank 41, and the SS is discarded by dehydration or the like as appropriate.

[0004] With the above apparatus, rapid sedimentation and separation of flocs and 15 to 150 m / sec, which is about ten times that of the conventional method, can be achieved.
h and a high processing flow rate. In addition, since the sand added to the water to be treated can be separated from the sedimented and separated flocs and reused, it is advantageous from the viewpoint of reducing the volume of waste and effectively utilizing materials.

It is generally well known that flocs formed by the coagulation sedimentation method do not always have a uniform size, and even under the same conditions, the particle size distribution of the floc is constant. Generally, there is a spread, and especially in an industrial-scale apparatus, it is inevitable that a large difference occurs in the sedimentation speed of the generated floc due to the influence of various fluctuation factors.

For example, the particle size is as large as about 1 to 4 mm,
The sedimentation speed is 15 to 10 for flocs that involve sand.
On the other hand, flocs whose particle size is as small as about 100 to 200 μm and which are not bound to sand or bound only to a small amount of sand, often have a sedimentation velocity of about 100 m / h. Is a very small fine floc of about 0.5 to 2 m / h. The factor of such fine floc generation is, for example, SS of raw water such as organic wastewater.
Inappropriate amounts of the flocculant added due to the nature of the components, fluctuations in the flow rate of the raw water, fluctuations in the quality of the raw water, and the like.

As an apparatus for performing the coagulation / sedimentation treatment other than the above, a granulation method and a sludge blanket method are known.

In the granulation method, as shown in FIG. 8, raw water to which an inorganic coagulant has been added is supplied from the bottom of a tank 51 in an ascending flow.
Stirring blade (flat plate etc.) so that the swirling flow in the tank 51 is horizontal
A blanket zone 53 of granulated particles is formed by using 52, sludge is extracted from an upper portion of the interface of the blanket zone 53, and a refining zone 54 is formed above the sludge. However, a concentration gradient is generated from the lower part to the upper part in the blanket zone 53, and relatively heavy particles collect at the lower part of the blanket, while relatively light particles collect at the upper part of the blanket. There is a problem that the upper light particles move to the fining zone 54 and cause deterioration of the quality of the treated water.

When the rising flow velocity in the tank increases and decreases, the blanket zone 53 expands and contracts, so that the particle concentration in the blanket zone 53 cannot be kept constant. As in the case described above, there is a problem that the quality of the treated water is degraded by shifting to the zone 54.

[0010] These problems also occur in the sludge blanket method.

Further, in the granulation method, the stirring blade 52 is swirled so that the swirling flow becomes horizontal in the tank. However, when the stirring blade 52 is enlarged, the difference in peripheral speed between the vicinity of the shaft and the tip of the blade is increased. However, there is also a problem that the size of the apparatus cannot be simply increased because the turbulence in the tank is caused and the quality of the treated water is deteriorated.

[0012]

As described above, in the case of a granulation method or a sludge blanket method in which a blanket zone is formed and coagulation and sedimentation is performed, water to be treated can be passed at a relatively high speed. Although there is an advantage, if the processing is performed at an extremely high speed, the blanket zone may be disturbed and the quality of the treated water may be deteriorated. There were various problems such as difficulty in increasing the size.

On the other hand, the method described with reference to FIG. 7 described above, in which insoluble particulate matter such as sand and an aggregating agent are added to the water to be treated, and SS agglomerates are generated and flocs are grown in a suspended state of the sand. ,
The advantage is that the density of the generated aggregates can be increased and high-speed water flow is possible.However, it is important to make the flocs as homogeneous as possible. It is necessary to produce a mixed flow such as upstream and downstream to grow flocs uniformly, and to sediment the generated flocs in the sedimentation tank to obtain clear treated water. There is a problem in that the installation area of the equipment increases due to the installation, and the installation cost increases.

The inventor of the present invention has made the above-mentioned prior art as follows.
The present inventors have made intensive studies for the purpose of developing a coagulating sedimentation apparatus which is less affected by the flow rate (flow velocity) of the water to be treated and which can reduce the installation area of the equipment as much as possible.

[0015]

The above object is achieved by the invention described in each claim of the present application.

[0016] The invention of the coagulation sedimentation apparatus according to claim 1 of the present invention is a method of adding sand and a coagulant to water to be treated, and coagulating a suspension (SS) in the water to be treated while the sand is suspended. A flocculation tank that generates floc, which is a coagulated and agglomerated material containing, a floc growth tank that grows floc while flowing the floc transferred from the flocculation tank with a vertical agitated flow, and an overflow wall. A flocculating sedimentation device comprising a floc growth tank and a sedimentation tank which is partitioned and has a large sedimentation speed containing flocks contained in the migration water passing over the overflow wall to sediment and discharge the floc out of the tank. , The flock growth tank,
A floc flow region formed at the lower part of the tank in the vertical direction so that the floc is stirred and flowed by the vertical stirring flow, and the floc flow region formed so that the vertical floc stirring flow by the stirring flow does not substantially reach. A refining region formed at the top of the region, and a treatment water outlet for discharging treated water in association with a free water surface at the top of the refining region, and the floc growth tank and the sedimentation tank are provided. The upper end of the overflow wall to be divided is located below the upper limit of the floc flow region.

In the above, the sand added to the coagulation tank is:
Although it is used as a typical example of the insoluble particulate matter, it is not limited to the use of sand, and any insoluble particulate matter having a specific gravity and particle size equivalent to this can be used instead. The particle size is preferably about 10 to 200 μm, and the specific gravity is about 2 to 3 (generally, the specific gravity of sand is about 2.7). As the coagulant, usually, polyaluminum chloride (PAC),
Inorganic flocculants such as ferric chloride and ferric sulfate, and polymeric flocculants such as anionic polymer flocculants and amphoteric polymer flocculants are used in combination. ) And sand, and a polymeric flocculant is used to grow aggregates into large flocs.

In the present invention, the inorganic coagulant is preferably added in the course of a raw water supply pipe for supplying the water to be treated (raw water) to the coagulation tank. It is preferable to perform line mixing to condense / aggregate SS in raw water. Known mixing means can be used for line mixing.

On the other hand, the polymer flocculant is added to the flocculation tank together with the sand. The agitation performed in this coagulation tank is performed with a strength required to bring the sand having a large specific gravity and easily settled into a suspended state, and the swirling agitating blade, a propeller type agitator, etc. It is performed so that flow occurs.

In order to transfer the agglomerate containing sand from the flocculation tank to the floc growth tank, in a preferred embodiment, an overflow method is adopted in which the aggregate moves over the upper end of the side wall surface of the flocculation tank. Desirably, a guide wall or the like is provided to allow the transferred aggregates to smoothly merge with the stirring flow in the floc growth tank by a guide path or the like.

The above-mentioned floc growth tank is one of the characteristic constitutions of the present invention, and is substantially divided into three parts in the vertical direction as described above. That is, a floc flow region partitioned at the lower part of the tank so that flocs of the aggregate transferred from the flocculation tank by the vertical agitated flow grow large, and a lower vertical agitated flow at the upper part of the floc flow region. And a treatment water outlet provided above the fining region. The outlet of this treated water is generally provided in an overflow manner.

It is not always necessary to provide a partition between each of the three sections in the vertical direction.
For example, as described later, by increasing the horizontal cross-sectional area of the floc flow region gradually or rapidly toward the fining region to make a difference in the ascending flow velocity, the flow region of the floc can be moved to a certain height range of the floc growth tank. Inside (below a certain height). In a preferred embodiment, depending on the type of agitating means for providing an agitated flow in the vertical direction in the floc flow region, the rotation speed of the blades for agitation, the structure of the tank (horizontal sectional diameter, tank height, etc.), etc. Stirring the floc in the direction can set the height limit over which the action of the flow will affect,
In a region above the limit height, the treated water rises in a horizontal cross-sectional area wider than the lower part of the tank. This area becomes a fining area. The fining area preferably has a larger (higher) dimension in the vertical direction, and a larger horizontal cross-sectional area enlargement rate is preferable in order to prevent the flow of minute flocs into the treated water. Also, since the tank cross-sectional area increases,
The tank height is generally 3 to 8 depending on the flow rate of the water to be treated.
m, preferably about 4 to 6 m in many cases, and the tank cross-sectional area of the fining area is often about 4 to 64 m ² , preferably about 16 to 36 m ^{2 in} many cases. .

The sedimentation tank provided subsequent to the floc growth tank discharges sludge as flocs settled at the bottom of the sedimentation tank out of the apparatus by a sludge drawing pump.
The sludge is returned to a separator such as a cyclone described in Japanese Patent No. 34230, and the separated sand is reused for addition to a flocculation tank. In this case, the sludge withdrawal is preferably performed continuously, so that the sludge withdrawal pump is smoothly operated, and the flow of floc into the sedimentation tank and the rise of the treated water in the fining area are not only performed smoothly. This is because it is effective for stabilizing the quality of treated water without giving a large fluctuation to the flow of the stream. Note that the terms floc growth tank and sedimentation tank are not necessarily limited to those having a tank structure that is independent in appearance and structure, and the area where the floc flows vertically and the floc spontaneously settle and settle. This is to identify a difference in function that an area to be divided is partitioned.

In the above construction, the upper end of the overflow wall partitioning between the floc growth tank and the sedimentation tank has a height in the range of 1/2 to 4/5 of the height of the floc flow region (claim 8). Generally, about 2 to 6 m), preferably 6/10 to 7
In many cases, it is better to be provided in the range of / 10. If the upper end of the overflow wall is provided at a position that is too high with respect to the floc flow area, the transfer of the floc to the settling tank is not performed smoothly, so that the floc is generally at a position lower than 4/5, preferably 7 or less. / 10. On the other hand, if the upper end of the overflow wall is too low with respect to the floc flow region, the partition from the floc flow region becomes ambiguous, and the stirring flow influences and disturbs the floc settling and sedimentation. The position is preferably higher than 1/2, preferably higher than 6/10.

According to the coagulation and sedimentation apparatus of the present invention having the above-described structure, unlike the above-described conventional method, clear treated water is discharged from the floc growth tank. Since there is no need for a large area of water surface to overflow and discharge, and thus it is not necessary to form the sedimentation tank itself as a large area tank, a scraper for collecting sedimentation flocs on a wide bottom surface can be eliminated. Further, what moves from the floc growth tank to the sedimentation tank is a floc having a high density and a high sedimentation speed and some accompanying water, so that the sedimentation tank can be made smaller.

Further, from these facts, while the floc growth tank and the sedimentation tank have a substantially single tank structure,
A large amount of water to be treated can be treated with a device having a small installation area.

Further, in the floc flow region in the floc growth tank, it is possible to stir using a propeller type stirring means that generates a vertical flow, and the deterioration of the treated water due to the fluctuation of the flow rate of the inflowing treated water. The apparatus can be provided with less influence of the above, and processing at a high flow rate can be realized.

Next, a second aspect of the present invention, which is a further improvement of the first aspect, will be described.

According to the second aspect of the present invention, the size of the apparatus can be further reduced as compared with the first aspect of the present invention.

That is, in the coagulation sedimentation apparatus according to claim 2, sand and a coagulant are added to the water to be treated, and the suspension (SS) in the water to be treated is coagulated in a state where the sand is suspended to remove the sand. A floc generation / growth tank for generating floc growth while causing flocculation / agglomerates containing the same to flow while being stirred by a vertical agitated flow, and an overflow wall partitioning the floc generation / growth tank from the overflow wall. A sedimentation tank for sedimenting floc having a high sedimentation velocity including sand contained in the migration water that has passed through the sedimentation tank and discharging the sediment out of the tank. A floc flow region formed at the lower part in the vertical direction in the tank so that the floc is stirred and flow by the agitated flow, and the floc flow region is formed so that the vertical floc stirred flow by the agitated flow does not substantially reach. Formed at the top And having a supernatant area, provided to have a treated water outlet for discharging treated water in conjunction free water surface of the upper 該清 Kiyoshi region, and the floc produced and
The upper end of the overflow wall dividing the growth tank and the settling tank is located below the upper limit of the floc flow region.

In the configuration of the second aspect of the present invention, the same parts as those of the first aspect can be configured in the same manner, and the differences will be described below.

One of the typical differences in the structure is that the coagulation-sedimentation apparatus according to the first aspect of the invention is an apparatus provided with a coagulation tank and a floc growth tank so as to be continuous. On the other hand, the coagulation / sedimentation apparatus according to the second aspect of the present invention is characterized in that the floc generation / growth tank has a substantially single tank structure.

In a preferred embodiment having such a configuration, the position of the addition of the polymer flocculant and the sand to the floc generation / growth tank is determined according to the tenth and eleventh aspects of the present invention. It is the water supply (inflow) position or its vicinity. The addition of the inorganic flocculant for coagulating the suspension (SS) in the water to be treated is performed by providing a coagulation tank in the stage preceding the floc generation / growth tank, as in the invention of claim 10. Alternatively, any configuration in which an inorganic coagulant is added to the supply pipe when water to be treated is directly supplied (flowed) to the floc generation / growth tank as in the invention of claim 11 can be selected.

A coagulation tank is provided in the preceding stage to cause a coagulation reaction between the inorganic coagulant and the SS in the tank, or an inorganic coagulant is added to the piping to perform a coagulation reaction with the SS by line mixing. For the selection of the method, a method suitable for the coagulation reaction can be adopted according to the nature and amount of SS contained in the water to be treated (raw water). However, the latter line mixing method can realize the downsizing of the apparatus, and preferable.

According to the present invention, an apparatus having substantially the same processing capacity as the coagulation and sedimentation tank of the invention of the first aspect in terms of the amount of treatment and the quality of the treated water can be implemented with a much smaller apparatus. it can.

According to a third aspect of the present invention, in the flock growth tank of the first aspect or the floc generation / growth tank of the second aspect, the horizontal cross-sectional area of the floc flow area is larger than that of the fining area. By providing a large area, the ascending flow velocity of the water to be treated in the fining area is reduced so that the floc stirring flow in the floc flow area does not substantially reach the fining area.

The horizontal cross-sectional area (S
₁ ) and the ratio (S ₂ / S ₁ ) of the horizontal cross-sectional area (S ₂ ) of the fining area
Is preferably large, and in a preferred embodiment, S ₂ / S ₁ =
1.1: 1 to about 2: 1, preferably 1.2: 1 to 1.
The ratio is preferably about 5: 1. When the ratio is 1.1: 1 or less, the amount of floc rising to the refining region increases, and it also increases to a floc having a relatively large particle size. On the other hand, if the ratio is 2: 1 or more, the horizontal cross-sectional area of the fining region becomes large, and the size of the entire apparatus is increased.
Alternatively, the horizontal cross-sectional area of the floc flow region becomes too small, which causes a problem that the amount of water flow (the amount of treated water) cannot be increased.

As described above, with a simple configuration in which the horizontal cross-sectional area of the fining region is set to be larger than that of the floc flowing region in which the flocs are stirred and flow in the vertical direction, the fine flocs rise from the fining region to the outside. Leakage can be sufficiently prevented.

According to a fourth aspect of the present invention, in the third aspect of the present invention, a floc growth tank or a floc generation / growth tank (hereinafter referred to as “flock growth tank or the like” includes both).
The sedimentation tank has a common free water surface, and is provided so as to form a substantially one tank structure having a treated water outlet for discharging treated water in association with the free water surface, and overflows the inside of the one tank. Separating the floc growth tank etc. and the sedimentation tank with the flow wall,
It is characterized in that the horizontal cross-sectional area of the fining area located above is larger than the horizontal cross-sectional area of the floc flow area.

Here, the above-mentioned "substantially one tank structure"
This is because a part of the lower part of the tank, which is substantially surrounded by one tank peripheral wall (outer wall), is defined as an "area where the floc flows vertically" and the other is "a floc spontaneously settles down. Area ". The upper part of the tank is divided into a portion located above and affected by the floc flow region, and a portion which is laterally separated from the floc flow region and hardly influenced by the floc flow region. According to the present invention, the mechanical structure can be formed so as to have two tanks (compartments) of a floc growth tank and a sedimentation tank in substantially one tank. In particular, the sedimentation tank has a narrow horizontal sectional area ( (Small) tank, so that the installation area of the entire apparatus can be reduced.

According to a fifth aspect of the present invention, in the third aspect of the present invention, the area of the free water surface of the floc growth tank or the like is reduced by covering the upper part of the area of the sedimentation tank with a shielding wall provided in water. It is characterized in that it is larger than the horizontal sectional area.

According to the present invention, the floc growth tank or the like and the sedimentation tank do not have a common free water surface as in the invention of the fourth aspect, but the upper part of the sedimentation tank region is shielded below the water surface. Higher isolation is obtained. It is needless to say that a free water surface can be formed on the upper part of the sedimentation tank by applying a pressurized gas to the upper part in the sedimentation tank area whose upper part is shielded.

According to the invention constructed as described above, the same operation as that of the invention of the third aspect, that is, two tanks of a floc growth tank and the like and a sedimentation tank are structurally provided in substantially one tank. In particular, since the sedimentation tank can be a tank having a narrower horizontal cross-sectional area, the installation area of the entire apparatus can be reduced, and the floc growth tank and the sedimentation tank can be more clearly defined. The advantage that the setting for the stirring means for the vertical stirring flow in the above can be simplified or facilitated.

According to a sixth aspect of the present invention, in the first aspect of the present invention, a rectifying means is provided between the floc flowing region of the floc coagulation / growth tank and the fining region above the floc flowing region. The invention of claim 7 is characterized in that, in the invention of claim 2 described above, a rectifying means is provided between the floc flow region of the floc generation and growth tank and the fining region above the floc flow region.

Appropriate means such as an inclined plate and a grating (square-shaped plate) can be used as the above-mentioned rectifying means. For example, a honeycomb-type inclined device can reduce the tank height. Therefore, it is preferably adopted.

According to these inventions, the rectifying means between the floc flowing region and the refining region, such as a floc growing tank,
It is possible to favorably suppress the transfer of fine flocs to the fining region, which is effective for improving the quality of treated water.

[0047]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram showing an example of a schematic configuration of a coagulation / sedimentation apparatus according to the present invention, wherein raw water to be treated (hereinafter simply referred to as “raw water”)
The raw water is supplied from a raw water supply pipe 1 to a flocculation tank 2 which is rapidly stirred. An inorganic coagulant addition pipe 3 is connected in the middle of the raw water supply pipe 1 so that the inorganic coagulant is added to the raw water and line mixing is performed by a stirring means (not shown). Reference numeral 4 denotes a polymer coagulant addition pipe for supplying a polymer coagulant to the coagulation tank 2, and reference numeral 5 denotes a sand addition pipe for similarly supplying sand to the coagulation tank 2. The addition of the polymer flocculant and the sand is selected so that the suspension (SS) is formed in the flocculation tank 2 at a position suitable for generating a condensate (fine floc) containing sand. You.

Reference numeral 201 denotes a stirring device provided in the coagulation tank 2, and the stirring blade 2011 is driven by a motor 2012.
The sand supplied to the coagulation tank 2 is rotated at a predetermined stirring speed to keep the sand in a suspended state without settling.

In the coagulation tank 2 configured as described above, most of the suspension contained in the raw water supplied to the coagulation tank 2 contains sand, an inorganic coagulant and a polymer coagulant. It becomes an agglomerate (condensate) containing sand in the treated water.

Next, the water to be treated containing the aggregates is transferred to the floc growth tank 6 which is slowly overflowed and agitated through the guide path 202. The guide path 202 is formed by a vertical partition wall in this example, and the floc is fed from the flocculation tank 2 in an overflowing manner, while the floc is supplied to the floc growth tank 6 so that the floc is grown and stirred for the flow of the floc. It is provided so as to open at a position where it can join. The floc growth tank 6 of the present embodiment has a single tank structure which is substantially integrated with the next settling tank 7, which will be described later.

The floc growth tank 6 of this embodiment is provided with a stirring device 601 having a propeller-type stirring blade 6011, and is contained in the water to be treated transferred from the flocculation tank 2 by a motor 6012. The agglomerate is rotated at a predetermined stirring speed so as to give the effect of a vertical stirring flow. The agglomerate absorbs the agglomerate by agitating and flowing within a predetermined height range (flock flow area: the area indicated by A in FIG. 1) by riding on the flow of the agitated flow in the vertical direction. Grow flock. This results in flocs having a large particle size and a high sedimentation velocity. In the present embodiment, the floc flow region is set so that the floc flows from the bottom of the floc growth tank 6 to a height of about ／ of the tank height, and the flow rate of the water to be treated and the rotation of the stirring device. The speed and the like are selected and set.

By generating the agitated flow as described above, a region where almost no floc rises (fining region: shown in FIG. 1B) is located above the floc flowing region of the floc growth tank 6. In addition, an overflow trough 602 having a gutter structure provided in a peripheral shape is provided as a treated water outlet at an upper portion thereof, and treated water is drained.

Numeral 7 denotes a sedimentation tank, into which the water to be treated is introduced over the upper part of the overflow wall 8 between the sedimentation tank 6 and the floc growth tank 6, and the bottom part is provided in an inverted conical shape. It is configured to facilitate the settling and settling of the floc (sludge) from the inverted conical top. That is, when the transfer water from the floc growth tank 6 containing the floc is transferred and introduced into the sedimentation tank 7, the floc has the property of having a large sedimentation speed, and thus quickly sediments to the bottom of the tank.
Then, the sludge is drawn by a sludge drawing pump 702 through a sludge drawing pipe 701 connected to the bottom. In this example, the sludge extracted by the sludge extraction pump 702 is sent to a cyclone 501 as a separator via a return pipe 703, and the sand separated from the sludge is supplied to the flocculation tank 2 from the sand addition pipe 5 described above. The recycling method is adopted. The sludge separated from the sand is discharged out of the system through a sludge discharge pipe 502.

The upper end of the overflow wall 8 is, in this example,
The height of the floc flow region in the floc growth tank 6 described above is set so as to be approximately ／, and the effect of the agitated flow in the flow region is affected by the shielding wall 9 in the sedimentation tank 7. Not covered. That is, the shielding wall 9 is formed by rising the vertical portion 902 upward from the vicinity of the bottom of the floc growth tank 6 along the overflow wall 8 so that the transfer water containing the floc from the bottom side is formed on the overflow wall 8. A sedimentation tank is formed by a slanted wall portion 903 formed so as to be continuous with the tank side wall below the water surface from a position above the upper end of the overflow wall 8 by forming a water passage 901 for guiding the upper end of the overflow wall 8. 7 is cut off except for the communication through the water passage 901.

Then, an inclined wall portion 90 extending from the upper end of the vertical portion 902 rising along the overflow wall 8 to the side wall of the settling tank 7.
By providing 3, the floc growth tank 6 has a configuration in which the horizontal cross-sectional area gradually increases from the floc flow region A to the fining region B, whereby the ascending flow velocity of the treated water is reduced in the fining region B. The fine flocs are suppressed from rising and moving to the refining area. Therefore the overflow gutter 70
The risk of leaking directly from 5 through the treated water discharge pipe 706 is greatly reduced, and highly purified treated water can be obtained.

According to the present embodiment, the floc growth tank 6 and the sedimentation tank 7 defined by the overflow wall 8 and the shielding wall 9 are provided in a tank having substantially one tank structure to constitute a small apparatus. This makes it possible to conveniently form a configuration in which the horizontal cross-sectional area of the fining area of the floc growth tank 6 is larger than that of the floc flow area. There is an advantage that can be obtained.

Further, the shielding wall 9 allows smooth sludge extraction without affecting the stirring tank 7 in the floc flow region to the sedimentation tank 7. Embodiment 2 The present embodiment shown in FIG. 2 is characterized in that the shielding wall 9 is omitted and a grating type straightening plate 10 that partitions a floc flow region and a fining region is provided, as compared with the above-described Embodiment 1. The other structure is substantially the same as that of the first embodiment.
Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In this embodiment, the overflow wall 8 functions to partition the floc growth tank and the sedimentation tank, and also functions to sharply increase the horizontal cross-sectional area in the refining area as compared with the floc flow area. . Although a relatively strong stirring flow is applied to the floc flow region in order to allow the floc to pass over the upper end of the overflow wall 8, the straightening plate 10 is provided, so that the fine floc rises and shifts to the refining region. Is sufficiently suppressed.

According to the apparatus of this example, substantially the same effects as in the first embodiment can be obtained. That is, the floc growth tank 6 and the sedimentation tank 7 divided by the overflow wall 8 and the shielding wall 9 can be provided in a tank having a substantially single tank structure to constitute a small apparatus. The structure in which the horizontal cross-sectional area of the fining region of the floc growth tank 6 is larger than that of the floc flow region can be conveniently formed, and the flow straightening plate 10 is provided. Can be further suppressed,
Thus, it is possible to obtain treated water having excellent water quality with a device having a small installation area. Third Embodiment A third embodiment shown in FIG. 3 is characterized in that an inclined plate-shaped current plate 11 is provided in the apparatus of the first embodiment to partition a floc flow region and a fining region. Is the same as in the first embodiment. Therefore, the same components are denoted by the same reference numerals as in the first embodiment, and description thereof is omitted.

According to the device of this example, the excellent effects of Embodiments 1 and 2 can be obtained simultaneously. That is, the floc growth tank 6 and the sedimentation tank 7 defined by the overflow wall 8 and the shielding wall 9 are provided in a tank having substantially one tank structure, and can constitute a small apparatus. Moreover, this makes it possible to conveniently form a configuration in which the horizontal cross-sectional area of the fining region of the floc growth tank 6 is larger than that of the floc flow region.

Further, the effect of the agitated flow in the floc flow region does not reach the settling tank 7 due to the shielding wall 9, so that the sludge can be smoothly extracted.

Further, since the rectifying plate 11 is provided, it is possible to further suppress the rise and transfer of the fine flocs to the refining area, thereby obtaining treated water having excellent water quality with a device having a small installation area. be able to. Embodiment 4 FIG. 4 is different from the coagulation / sedimentation apparatus of Embodiment 1 in the following points, but the other points are the same.

That is, the tank configuration (a tank configuration having a flocculation tank, a floc growth tank, and a sedimentation tank) is the same,
The structure is also common in having the shielding wall 9.

On the other hand, the structure of the bottom of the floc growth tank 61 is different from that of the first embodiment, and is provided in the shape of an inverted truncated cone in the shape of a cone extending from the peripheral wall to the bottom, thereby forming a dead zone where the floc may stay. We try to promote fluidity with as little as possible. Further, an inorganic coagulant is added to the coagulation tank 2 and the polymer coagulant is added to the guide path 20.
Embodiment 1 is that the addition is made at a position facing the floc growth tank 61 and that the sand is further added at a position where the guide path 202 in the floc growth tank 61 is open.
Is different from

The point different from the first embodiment will be described. First, by forming the bottom structure of the floc growth tank 61 into a cone shape, the floc flow stirring in the vertical direction in the floc growth tank 61 provided by the stirring device 601 is performed. There is an advantage that the dead zone which is likely to occur at the lower corner of the straight cylindrical tank by the flow alone can be eliminated by the structure of the tank.

In the present embodiment, the addition position of the polymer flocculant and the addition position of the sand are changed as described above, so that the flocculation tank 2 for adding the inorganic flocculant to form a coagulated suspension. In addition, the function of the floc growth tank 61 for growing this condensate as floc can be divided, and an advantage that a structure suitable for each function can be adopted can be obtained. Embodiment 5 The present embodiment shown in FIG. 5 is similar to the relationship between Embodiment 1 (see FIG. 1) and Embodiment 4 (see FIG. 4), which is a modified example of Embodiment 1, (see FIG. 2). In the following, an example for explaining a relationship which is a modified example will be described, in which structurally identical members and structural portions are denoted by the same reference numerals, and description thereof will be omitted.

According to the device of this example, the respective effects of the second and fourth embodiments can be obtained.

That is, by making the bottom structure of the floc growth tank 61 cone-shaped, only the vertical floc flow agitation flow in the floc growth tank 61 provided by the stirrer 601 easily occurs at the lower corner of the straight cylindrical tank. The dead zone can be eliminated by the structure of the tank. Also, inorganic coagulants,
By setting the addition position of the polymer flocculant and the sand in the same manner as in the fourth embodiment, the action in the flocculation tank 2 for generating the condensate and the action in the floc growth tank 61 for growing the condensate as flocs are separated. And a structure suitable for each can be adopted. Embodiment 6 FIG. 6 shows an example of the configuration of another coagulation / sedimentation apparatus of the present invention. The water to be treated (raw water) is supplied from a raw water supply pipe 1 to a floc growth tank 62 which is slowly stirred. The inorganic coagulant is added to the raw water from the inorganic coagulant supply pipe 3 connected in the middle of the raw water supply pipe 1, and is stirred by a line mixer to generate a condensate of SS and fine floc in the raw water. I have. In this example, the coagulation tank 2 shown in Embodiments 1 to 5 is omitted, but this coagulation tank 2 is not essential in the practice of the present invention, and the inorganic coagulant in the middle of the raw water supply pipe 1 is not used. Can be replaced by the addition of water and line mixing, and which of the formation of the condensate in the pipe and the formation of the condensate by rapid stirring in the coagulation tank depends on the amount of the SS contained in the raw water. It can be selected and adopted depending on the amount, nature, treated water amount, or installation area of the apparatus.

Reference numeral 4 denotes a polymer coagulant addition pipe for supplying the polymer coagulant. In this embodiment, the pipe is provided near the end of the raw water supply pipe 1 so as to be added to the raw water supply pipe 1 as shown in the figure. Although this example is shown, it may be provided so as to be added to the floc growth tank 62. Reference numeral 5 denotes a sand addition pipe for adding sand near the raw water supply position below the floc growth tank 62.

Reference numeral 201 denotes a stirrer provided in the floc growth tank 62, which is the same as in the first embodiment. Note that the floc growth tank 62 of the present embodiment is the
Similarly to the above, the structure at the bottom of the tank is provided in a cone shape so as to increase the flowability of the floc and to minimize the formation of a dead zone at the lower corner of the lower part of the tank where flow is poor.

Numeral 7 denotes a sedimentation tank, in which the water to be treated overflows and is introduced over the overflow wall 8 between the floc growth tank 62 and the bottom thereof is provided in an inverted conical shape. The sedimented and settled floc (sludge) is provided so that it can be easily extracted from the inverted conical bottom.

Reference numeral 10 denotes a current plate provided over the upper portions of the floc growth tank 62 and the sedimentation tank 7. Wall 8 (for example, tank height 3)
Since the horizontal cross-sectional area of the tank above the top of / 4) is large, the upflow in the fining area where the influence of the stirring water flow in the floc flow area below the floc growth tank 62 is small is further stabilized, and the overflow trough 602 is formed. This has the effect of further reducing the possibility of fine flocs being contained in the treated water discharged from the tank.

According to the coagulating sedimentation apparatus having the above configuration, most of the suspension (SS) contained in the raw water (water to be treated) is supplied to the raw water supply pipe 1 to which the inorganic coagulant is added. The mixture is condensed into fine flocs by the line mixing, and the water to be treated containing the flocs is supplied to the floc growth tank 62, and is simultaneously stirred and fluidized in the floc flow area at the bottom of the tank together with the added polymer flocculant and sand. The floc contained in the treated water that has risen to the fining area sediments downward due to its sedimentation, and grows into a large floc having a large particle diameter and a large sedimentation velocity. If the water flows into the cyclone, it will quickly settle out and be extracted as sludge and returned to the cyclone 501.
The treated water is discharged from the overflow trough 602 through the current plate 10.

Further, the floc growth tank 62 and the sedimentation tank 7 partitioned by the overflow wall 8 can be provided in a tank having a substantially single tank structure to constitute a small apparatus. A configuration is advantageously formed in which the horizontal cross-sectional area of the fining region of the floc growth tank 6 is larger than that of the floc flow region. Further, the effect of the stirring flow in the floc flow region does not reach the sedimentation tank 7 due to the shielding wall 9, so that the sludge can be smoothly extracted.

[0075]

As described above, according to the present invention, clear treated water is discharged from the floc growth tank, so that a large surface area for overflowing and discharging the treated water in the settling tank is not required. Therefore, a raking machine for raking the settling floc at the bottom of the wide sedimentation tank is unnecessary, and the size of the sedimentation tank can be reduced.

From these facts, it is possible to treat a large amount of water to be treated by an apparatus having a small installation area while the floc growth tank and the sedimentation tank have substantially one tank structure.

Further, the floc flow region in the floc growth tank can be agitated by using a propeller-type agitating means which generates a vertical flow, and the deterioration of the treated water due to the fluctuation of the flow rate of the inflowing treated water can be reduced. An apparatus with little influence can be provided, and processing at a high flow rate can be realized.

According to the second aspect of the present invention, the rectification means is provided between the floc flowing region and the fining region of the floc growth tank, so that the transfer of fine floc to the fining region is further suppressed. To obtain treated water having good water quality.

Further, according to the fifth aspect of the present invention, it is possible to substantially eliminate the adverse effect of the agitated flow in the floc flow region on the transfer water containing the floc which migrates from the floc growth tank to the sedimentation tank. Can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a coagulation / sedimentation apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a coagulation / sedimentation apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a schematic configuration of a coagulation / sedimentation apparatus according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a schematic configuration of a coagulation / sedimentation apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a schematic configuration of a coagulation / sedimentation apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a view showing a schematic configuration of a coagulation / sedimentation apparatus according to a sixth embodiment of the present invention.

FIG. 7 is a diagram showing a schematic configuration of an example of a conventional coagulation / sedimentation apparatus.

FIG. 8 is a diagram showing a schematic configuration of another example of the conventional coagulation / sedimentation apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Raw water supply pipe 2 ... Coagulation tank 201 ... Stirrer 2011 ... Stirrer blade 2012 ... Motor 202 ... Guideway 3 ... Inorganic coagulant addition pipe 4 ... High Pipe for adding molecular coagulant 5 ・ ・ ・ Pipe for adding sand 501 ・ ・ ・ Cyclone 502 Sludge discharge pipe 6 ・ ・ ・ Flocking growth tank 601 ・ ・ ・ Stirring device 6011 ・ ・ ・ Stirring blade 6012 ・ ・ ・ Motor 602 ・ ・ ・ Overflow Flow trough 7: sedimentation tank 701: sludge extraction pipe 702: sludge extraction pump 703 ... return pipe 8 ... overflow wall 9 ... shielding wall 901 ... water passage 902 ...・ Vertical portion 903 ・ ・ ・ Inclination portion 10, 11 ・ ・ ・ Rectifier plate A ・ ・ ・ Floc flow region B ・ ・ ・ Clarification region.

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[Procedure amendment]

[Submission Date] February 18, 2000 (2000.2.1
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

In this method, the specific gravity of floc to be settled and separated by the coagulation sedimentation method is generally about 1.01 to 1.02, and the sedimentation speed is low. The floc can be given a large sedimentation velocity by containing the flocculant. For example, as shown in FIG. (Inorganic flocculant and polymer flocculant) and sand are added, and a rapid stirring tank 41 is formed to form a coagulated product of the sand and the suspension with rapid stirring. A slow stirring tank 42 in which small aggregates are grown into large flocs while slowly stirring, and water to be treated is transferred from the slow stirring tank 42 by an overflow method to precipitate flocs having a large sedimentation velocity including sand. And tilt It is carried out by configured flocculator device to comprise a settling tank 43 for discharging the clear treated water separated floc from the top through the rectifying means such as a leaf 44 to the outside. The floc (sludge) settled and separated from the treated water in the sedimentation tank 43 is drawn out of the tank by a sludge drawing pump 45 and sent to a cyclone 46, where SS and sand in the combined sludge are separated, and the sand is separated. The SS is reused as sand to be added to the rapid stirring tank 41, and the SS is discarded by dehydration or the like as appropriate.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0055

[Correction method] Change

[Correction contents]

Then, an inclined wall portion 90 extending from the upper end of the rising vertical portion 902 along the overflow wall 8 to the side wall of the settling tank 7.
By providing 3, the floc growth tank 6 has a configuration in which the horizontal cross-sectional area gradually increases from the floc flow region A to the fining region B, whereby the ascending flow velocity of the treated water is reduced in the fining region B. The fine flocs are suppressed from rising and moving to the refining area. Therefore overflow trough
Direct leakage is danger from 602 through the treated water discharge piping is would be greatly reduced, it is possible to obtain a high clear treated water.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0059

[Correction method] Change

[Correction contents]

According to the apparatus of this example, substantially the same effects as in the first embodiment can be obtained. That is, the floc growth tank 6 and the sedimentation tank 7 divided by the overflow wall 8 can be provided in a tank having a substantially single tank structure to constitute a small apparatus. This makes it possible to conveniently form a configuration in which the horizontal cross-sectional area of the fining area of the floc growth tank 6 is larger than that of the floc flow area. Thus, treated water having excellent water quality can be obtained with a device having a small installation area. Third Embodiment A third embodiment shown in FIG. 3 is characterized in that an inclined plate-shaped current plate 11 is provided in the apparatus of the first embodiment to partition a floc flow region and a fining region. Is the same as in the first embodiment. Therefore, the same components are denoted by the same reference numerals as in the first embodiment, and description thereof will be omitted.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

That is, by making the bottom structure of the floc growth tank 61 cone-shaped, only the vertical floc flow agitation flow in the floc growth tank 61 provided by the stirrer 601 easily occurs at the lower corner of the straight cylindrical tank. The dead zone can be eliminated by the structure of the tank. Also, inorganic coagulants,
By setting the addition position of the polymer flocculant and the sand in the same manner as in the fourth embodiment, the action in the flocculation tank 2 for generating the condensate and the action in the floc growth tank 61 for growing the condensate as flocs are separated. And a structure suitable for each can be adopted. Sixth Embodiment FIG. 6 shows an example of a schematic configuration of another coagulation / sedimentation apparatus of the present invention. Water to be treated (raw water) is supplied from a raw water supply pipe 1 to a floc growth tank 62 that is slowly stirred. You. The inorganic coagulant is added to the raw water from the inorganic coagulant supply pipe 3 connected in the middle of the raw water supply pipe 1, and is stirred by a line mixer to generate a condensate of SS and fine floc in the raw water. I have. In this example, the first to fifth embodiments are described.
Although the flocculation tank 2 shown by is omitted, this flocculation tank 2 is not essential in the practice of the present invention, and can be replaced by adding an inorganic flocculant to the middle of the raw water supply pipe 1 and line mixing. There is a choice between the formation of condensate in the pipe and the formation of condensate by rapid stirring in the flocculation tank, depending on the amount and properties of SS contained in the raw water,
It can be selected and adopted depending on the amount of treated water or the installation area of the apparatus.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

Further, the floc growth tank 62 and the sedimentation tank 7 partitioned by the overflow wall 8 can be provided in a tank having a substantially single tank structure to constitute a small apparatus. A configuration in which the horizontal cross-sectional area of the fining region of the floc growth tank 6 is larger than that of the floc flow region is conveniently formed .

Claims (11)

[Claims] 1. A floc which is a flocculent / agglomerated material containing sand by adding sand and a flocculant to the water to be treated and aggregating a suspension (SS) in the water to be treated while the sand is suspended. , A floc growth tank for performing floc growth while causing the floc transferred from the flocculation tank to flow with a vertical agitated flow, and an overflow wall partitioned from the floc growth tank to form the overflow. A sedimentation tank for sedimenting floc having a large sedimentation velocity including sand contained in the migration water that has passed over the wall, and discharging the sediment out of the tank. A floc flow region formed at the lower part in the vertical direction in the tank so that the floc is stirred and flow by the stirring flow, and an upper part of the floc flow region so that the vertical floc stirring flow by the stirring flow does not substantially reach. Formed in And having a supernatant area,
An upper end of an overflow wall which is provided so as to have a treated water outlet for discharging treated water in association with a free water surface above the clarifying region and which partitions the floc growth tank and the sedimentation tank is an upper limit of the floc flow region. A coagulating sedimentation device, which is positioned below the coagulating sedimentation device. 2. A sand and a flocculant are added to the water to be treated, and the suspension (SS) in the water to be treated is flocculated in a state where the sand is suspended to form a coagulated / agglomerated material containing sand. At the same time, a floc generation / growth tank that causes floc growth while flowing with a vertical agitated flow, and this floc agglomeration / growth tank that is separated by an overflow wall are included in the migration water that has passed through the overflow wall. A flocculating sedimentation apparatus comprising: a sedimentation tank for sedimenting floc having a large sedimentation velocity including sand, and discharging the floc out of the tank. And a fining region formed in the upper portion of the floc flow region so that the vertical floc stirring flow by the stirring flow does not substantially reach. And the fining territory Is provided so as to have a treated water outlet for discharging treated water in association with a free water surface at an upper portion of the floc generation / growth tank and the settling tank. A coagulating sedimentation device, wherein the coagulating sedimentation device is also positioned below. 3. The floc growth tank of claim 1 or claim 2.
The floc generation / growth tank reduces the ascending flow rate of the water to be treated in the fining region by increasing the horizontal cross-sectional area of the fining region compared to the horizontal cross-sectional area of the floc flowing region, so that the floc stirring flow 3 does not substantially extend to the refining region.
3. The coagulation sedimentation apparatus according to item 1. 4. The floc growth tank or floc generation / growth tank according to claim 3, wherein the sedimentation tank has a common free water surface and a treated water outlet for discharging treated water in association with the free water surface. The flock growth tank or the floc generation / growth tank is separated from the sedimentation tank by an overflow wall so that the inside of the one tank has an upper portion as compared with the horizontal cross-sectional area of the flock flow region. A coagulating sedimentation apparatus characterized in that the horizontal cross-sectional area of the fining region located in the area is increased. 5. The method according to claim 3, wherein the upper part of the settling tank is covered from the upper end of the overflow wall by a shielding wall provided in water,
A flocculation settling apparatus characterized in that the free water surface area of the floc growth tank or the floc generation / growth tank is larger than the horizontal sectional area of the floc flow region. 6. The coagulating sedimentation apparatus according to claim 1, wherein a rectifying means is provided between the floc flow region of the floc growth tank and the clarification region above the floc flow region. 7. The method according to claim 2, wherein
A coagulating sedimentation apparatus comprising a rectifying means provided between a floc flow region of a floc generation / growth tank and a clarification region above the floc flow region. 8. The method according to claim 1, wherein
Set the upper end of the overflow wall to 1/2 to 4 of the height of the floc flow area.
A coagulating sedimentation apparatus characterized in that it is set within the range of / 5. 9. The method according to claim 1, wherein a pipe for adding an inorganic coagulant for coagulating a suspension in the water to be treated is connected to a middle of a supply pipe for supplying the water to be treated to a coagulation tank. A stirring means is provided in the pipe downstream of the inorganic coagulant addition position, and the coagulation tank is provided so as to add a polymer coagulant and sand that contribute to the growth of coagulated floc. Coagulating sedimentation equipment. 10. The coagulation tank for adding an inorganic coagulant for coagulating a suspension in water to be treated according to claim 2,
The flocculation / growth tank was provided at the preceding stage, and the addition point of the polymer flocculant and sand contributing to floc growth was provided at or near the transfer position of the water to be treated from the coagulation tank to the floc formation / growth tank. A coagulation sedimentation apparatus characterized by the above-mentioned. 11. A pipe according to claim 2, wherein a pipe for adding an inorganic coagulant for coagulating a suspension in the water to be treated is connected to a middle of a supply pipe for supplying the water to be treated to a floc generation / growth tank. At the same time, a stirring means is provided inside the pipe downstream of the inorganic flocculant addition position, and the polymer flocculant and sand adding positions contributing to the growth of floc are introduced into the floc generation / growth tank. A coagulation sedimentation device provided at or near a position.