JP3866439B2 - Coagulation sedimentation equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for coagulating and precipitating a suspension (SS) in water to be treated. Specifically, sand can be added to the water to be treated to efficiently perform coagulation and precipitation at a high sedimentation rate. The present invention relates to a coagulation precipitation apparatus for removing SS.
[0002]
[Prior art]
As an agglomeration and precipitation device that removes fine organic and inorganic suspensions (SS), it is possible to rapidly settle and precipitate by agglomerating and flock-growing SS in the water to be treated. For example, Japanese Patent No. 2634230, Japanese Patent Application Laid-Open No. Hei. This is proposed in Japanese Patent Laid-Open No. 8-47606.
[0003]
In this method, compared to the fact that the specific gravity of flocs to be settled and separated by the coagulation sedimentation method is generally about 1.01 to 1.02 and the sedimentation speed is low, heavy flocs having a specific gravity of, for example, about 2.7 are included in the flocs. In this way, the floc can be given a large settling velocity. For example, as shown in FIG. 7, a flocculant (usually an inorganic flocculant) is added to the raw water (treated water) containing the suspension (SS). And a polymer flocculant) and sand are added to form agglomerates in which sand and suspension are combined with rapid stirring, and the water to be treated transferred from the rapid stirring tank 41 is slowly stirred. While the slow agitation tank 42 that grows small agglomerates into large flocs, the water to be treated is transferred from the slow agitation tank 42 by an overflow method, and flocs with a large sedimentation speed including sand are precipitated, Inclined plate 44 etc. It is carried out by configured flocculator device to comprise a settling tank 43 for discharging the clear treated water separated from the upper floc through the rectifier means 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 the sludge extraction pump 45 and sent to the cyclone 46 to separate SS and sand in the combined sludge and remove the sand.Rapid stirring tankIt is reused as sand to be added to 41, and SS is appropriately disposed of by dehydration.
[0004]
With the above apparatus, rapid sedimentation separation of flocs and a high processing flow rate of 15 to 150 m / h, which is about ten times that of the conventional method, are realized. Moreover, since the sand added to the water to be treated can be separated from the flocs separated and separated and reused, it is advantageous from the viewpoint of reducing the volume of waste and effectively using materials.
[0005]
By the way, it is generally well known that flocs produced by the coagulation precipitation method are not uniformly equal in size, and there is a certain spread in floc particle size distribution even under the same conditions. In general, industrial scale devices are affected by various factors of variation, and it is inevitable that a large difference occurs in the sedimentation rate of the generated floc.
[0006]
For example, some flocs having a large particle size of about 1 to 4 mm and entraining sand may have a sedimentation speed of 15 to 1000 m / h. On the other hand, the particle size is about 100 to 200 μm and In many cases, flocs that are not bonded or only bonded to a small amount of sand are extremely small flocs with a sedimentation speed of about 0.5 to 2 m / h. The cause of such fine floc generation includes, for example, the nature of the SS component of raw water such as organic waste water, fluctuations in the raw water flow rate, and inappropriateness of the amount of flocculant added due to fluctuations in the raw water quality.
[0007]
As an apparatus for performing a coagulation-precipitation treatment other than the above, a granulation method and a sludge blanket method are known.
[0008]
As shown in FIG. 8, the granulation method is performed by supplying raw water to which an inorganic flocculant has been added from the bottom of the tank 51 in an upward flow so that the swirling flow in the tank 51 becomes horizontal (flat plate or the like). A blanket zone 53 of granulated particles is formed using 52, sludge is extracted from the upper interface of the blanket zone 53, and a clarification zone 54 is formed thereon. However, a concentration gradient is generated from the lower part to the upper part in the blanket zone 53, and relatively heavy particles gather at the lower part of the blanket. On the other hand, relatively light particles gather at the upper part of the blanket. There is a problem that light particles in the upper part migrate to the clarification zone 54 and cause deterioration of the quality of treated water.
[0009]
In addition, when the rising flow rate in the tank increases or decreases, the blanket zone 53 expands or contracts, and the particle concentration in the blanket zone 53 cannot be kept constant. It becomes a problem which causes the water quality deterioration of treated water like the above case.
[0010]
These are also problematic in the sludge blanket method.
[0011]
Further, in the granulation method, the stirring blade 52 is swirled so that the swirling flow is horizontal in the tank. However, when the stirring blade 52 is enlarged, the difference between the peripheral speed of the vicinity of the shaft and the tip of the blade increases. There is also a problem that the apparatus cannot be simply increased in size because it causes disturbance in the tank and causes deterioration of the quality of the treated water.
[0012]
[Problems to be solved by the invention]
As described above, in the case of the granulation method or sludge blanket method in which a blanket zone is formed and the coagulation sedimentation treatment is performed, there is an advantage that the water to be treated can be passed at a relatively high speed, but the treatment speed is too high. If this is done, problems such as disturbance of the blanket zone and deterioration of the quality of the treated water, deterioration of water quality due to fluctuations in the flow rate of the water flow, and difficulty in increasing the size of the device was there.
[0013]
On the other hand, insoluble particulate matter such as sand and flocculant are added to the water to be treated, and the above-described method shown in FIG. 7 for generating SS agglomerates and growing flocs under the suspended state of sand is generated. The advantage is that the density of agglomerates can be increased and high-speed water flow is possible, but it is important to make the flocs as homogeneous as possible. It is necessary to make the flocs grow homogeneously by generating a mixed flow of the like, and to settle the generated flocs in the sedimentation tank to obtain clear treated water. However, there is a problem that the installation area of the equipment becomes large and the installation cost increases.
[0014]
Under the conventional technology as described above, the present inventor has intensively studied for the purpose of developing a coagulating sedimentation apparatus that is less affected by fluctuations in the flow rate (flow velocity) of water to be treated and that can reduce the installation area of equipment as much as possible. Repeatedly, the present invention has been made.
[0015]
[Means for Solving the Problems]
The above object can be achieved by the inventions described in the claims of the present application.
[0016]
The invention of the coagulation precipitation apparatus according to claim 1 of the present invention includes sand by adding sand and a flocculant to the water to be treated, and aggregating the suspension (SS) in the water to be treated in a state where the sand is suspended. An agglomeration tank that generates flocs that are condensed and agglomerated, a floc growth tank that allows flocs to migrate while the flocs transferred from the agglomeration tank are flowed by a stirring flow in the vertical direction, and this floc growth tank by an overflow wall And a sedimentation tank that settles flocs having a large sedimentation speed and contains sand contained in the transition water that has passed through the overflow wall and discharges the flocs outside the tank. The growth tank has a floc flow region formed at the lower part in the vertical direction in the tank so that the flocs are stirred and flowed by the vertical stirring flow, and the vertical floc stirring flow by the stirring flow is not substantially affected. To the floc flow A clarification region formed at the upper part of the region, and a treatment water outlet for discharging the treatment water in association with the free water surface at the upper part of the clarification region, and the flock growth tank and the precipitation tank. The upper end of the partitioning overflow wall is located below the upper limit of the flock flow region.
[0017]
In the above, the sand added to the agglomeration tank is used as a typical insoluble granular material, but is not limited to the use of sand and is an insoluble granular material having a specific gravity and particle size equivalent to this. Of course, it can be used instead. A particle size of about 10 to 200 μm is preferably used, and a specific gravity of about 2 to 3 (generally a specific gravity of sand of about 2.7) is used. As the flocculant, inorganic flocculants such as polyaluminum chloride (PAC), ferric chloride, ferric sulfate, and polymer flocculants such as anionic polymer flocculants and amphoteric polymer flocculants are usually used in combination. Inorganic flocculants are used to agglomerate suspensions (SS) and sand in the treated water, and polymer flocculants are used to grow the agglomerates into large flocs.
[0018]
The addition of the inorganic flocculant in the present invention is preferably performed in the middle of the raw water supply pipe for supplying the water to be treated (raw water) to the coagulation tank, as in the ninth aspect of the invention. Thus, it is preferable to cause the SS in the raw water to condense and aggregate. A known mixing means can be used for line mixing.
[0019]
On the other hand, the polymer flocculant is added to the agglomeration tank together with sand. The agitation performed in the agglomeration tank is performed at a strength required to make the sand having a large specific gravity and easily settled into a suspended state, and the vertical agitation is performed using a swirling agitating blade, a propeller type agitator, and the like. The flow is performed.
[0020]
In order to transfer the agglomerates containing sand from the agglomeration tank to the floc growth tank, in a preferred embodiment, an overflow mode is adopted in which the transition proceeds over the upper end of the side wall surface of the agglomeration tank. Desirably, it is preferable to provide a guide wall or the like that smoothly merges the transferred agglomerates with the stirring flow in the floc growth tank through a guide path or the like.
[0021]
The flock growth tank is one of the characteristic structures of the present invention, and is substantially divided into three parts in the vertical direction as described above. That is, a floc flow region divided in the lower part of the tank so that the flocs of the agglomerates transferred from the coagulation tank are greatly grown by the vertical stirring flow, and the lower vertical stirring flow in the upper part of the floc flow region The clarification area which is not substantially affected by the above-mentioned operation and the outlet of the treated water provided in the upper part of the clarification area are partitioned. The treated water outlet is generally provided in an overflow form.
[0022]
It is not always necessary to provide a partition between each of the three sections divided in the above vertical direction. For example, as described later, the horizontal cross-sectional area of the floc flow area gradually or rapidly expands toward the clarification area. By making a difference in the ascending flow velocity, the flow region of the floc can be set within a certain height range (below a certain height) of the floc growth tank. In a preferred embodiment, depending on the type of stirring means for giving a stirring flow in the vertical direction in the flock flow region, the rotational speed of the blade for stirring, the structure of the tank (horizontal sectional diameter, tank height, etc.), etc. It is possible to set the height limit where the action of the stirring flow is applied to the floc in the direction, and in the region above the limit height, the treated water rises in a wider horizontal cross-sectional area than the bottom of the tank. This area becomes the clear area. The clarified area has a larger (higher) dimension in the vertical direction, and a larger horizontal cross-sectional area is preferred in order to prevent the minute floc from flowing into the treated water, but the tank height is increased. In addition, since the tank cross-sectional area becomes large, the tank height is generally about 3 to 8 m, preferably about 4 to 6 m, although it depends on the flow rate of water to be treated. The tank cross-sectional area of the area is 4 to 64m² Degree, preferably 16-36m² In many cases, it is good to set the range of the degree.
[0023]
A sedimentation tank provided subsequent to the floc growth tank discharges sludge as floc precipitated at the bottom of the floc to the outside of the apparatus by a sludge extraction pump. Usually, a cyclone as described in the above-mentioned Japanese Patent No. 2634230, etc. The sludge is returned to the separator, and the separated sand is reused for addition to the coagulation tank. In this case, it is preferable to perform the sludge extraction continuously, and the continuous operation of the sludge extraction pump not only facilitates the flow of the flocs to the settling tank but also the rise of the treated water in the clarification area. This is because it is effective in stabilizing the quality of the treated water without giving a large fluctuation to the flow. The terms “floc growth tank” and “sedimentation tank” are not necessarily limited to having a tank structure that is independent in appearance. The area where the flocs flow in the vertical direction and the flocs naturally settle and settle. The functional difference that the area to be performed is partitioned is specified.
[0024]
In the above configuration, the upper end of the overflow wall that divides the floc growth tank and the sedimentation tank is, as shown in claim 8, a range of 1/2 to 4/5 of the height of the floc flow region (generally Is preferably about 2 to 6 m), preferably in the range of 6/10 to 7/10. If the upper end of the overflow wall is provided at a position that is too high with respect to the floc flow region, the transition of the floc to the settling tank will not be carried out smoothly, so that it is generally lower than 4/5, preferably 7 The position is lower than / 10. On the other hand, if the upper end of the overflow wall is too low with respect to the floc flow area, the partition with the floc flow area becomes ambiguous and the stirring flow affects the floc settlement and sedimentation, which is generally In this case, the position is higher than ½, preferably higher than 6/10.
[0025]
According to the coagulating sedimentation apparatus of the present invention having the above-described configuration, unlike the conventional method described above, the clear treated water is discharged from the floc growth tank. Therefore, it is not necessary to form the precipitation tank itself as a large area tank, and therefore a scraping machine for scraping the sedimentation floc on the large bottom surface can be dispensed with. Moreover, what moves from a floc growth tank to a sedimentation tank is a floc with a high density and a fast sedimentation speed, and some accompanying water, and can make a precipitation tank small.
[0026]
Furthermore, from these facts, a large amount of water to be treated can be treated with an apparatus having a small installation area while the floc growth tank and the sedimentation tank are substantially of a single tank structure.
[0027]
In addition, in the floc flow region in the floc growth tank, stirring can be performed using a propeller-type stirring means in which vertical flow occurs, and the influence of deterioration of treated water due to fluctuations in the flow rate of treated water flowing in Fewer devices can be provided, and processing at a high flow rate can be realized.
[0028]
Next, the invention of claim 2 which is an improvement of the invention of claim 1 will be described.
[0029]
The invention of claim 2 can further reduce the size of the apparatus as compared with the invention of claim 1 described above.
[0030]
That is, the coagulating sedimentation apparatus according to claim 2 adds sand and a flocculant to the water to be treated, and agglomerates the suspension (SS) in the water to be treated in a state where the sand is suspended, thereby condensing the sand.・ Flock generation that causes floc growth while generating agglomerates and flowing with a stirring flow in the vertical direction. ・ The floc generation and growth tank are separated from this floc by the growth tank and the overflow wall. A coagulating sedimentation apparatus comprising a sedimentation tank that settles flocs having a large sedimentation speed including sand contained in the transition water and discharges the flocs outside the tank, wherein the floc generation / growth tank has a vertical stirring flow The floc flow region formed in the lower part in the vertical direction in the tank so that the floc stirs and flows, and the upper part of the floc flow region so that the vertical floc stirring flow by the stirring flow does not substantially reach With the Kiyosumi area In addition, the upper end of the overflow wall provided with a treated water outlet for discharging treated water in conjunction with the free water surface at the top of the clarification region, and dividing the floc generating / growing tank and the settling tank, It is characterized by being positioned below the upper limit of the flock flow region.
[0031]
Of the configuration of the invention of the second aspect, the same parts as those of the first aspect can be configured in the same manner, and therefore the different parts will be described below.
[0032]
A typical difference in configuration is that the coagulation sedimentation apparatus of the invention of claim 1 is an apparatus in which the coagulation tank and the floc growth tank are provided so as to be continuous in two tanks. The coagulation sedimentation apparatus according to the invention of Item 2 is that the floc producing / growing tank is substantially in one tank structure.
[0033]
In a preferred embodiment of such a configuration, the position of addition of the polymer flocculant and sand to the floc generating / growth tank is the supply of water to be treated supplied to the tank as in the inventions of claims 10 and 11. (Inflow) position or its vicinity. In addition, the addition of the inorganic flocculant for coagulating the suspension (SS) in the water to be treated is added to this tank by providing a coagulation tank in front of the floc generation / growth tank as in the invention of claim 10. Alternatively, as in the invention of claim 11, when the water to be treated is directly supplied (inflowed) to the floc generating / growing tank, any configuration in which the inorganic flocculant is added to the supply pipe can be selected.
[0034]
Selection of a system in which a coagulation tank is provided in the previous stage to cause the coagulation reaction between the inorganic flocculant and SS in the tank, and a system in which the coagulation reaction with SS is performed by adding an inorganic coagulant to the pipe and performing line mixing Can be used in accordance with the nature and amount of SS contained in the water to be treated (raw water), but the latter line mixing method is more preferable because the size of the apparatus can be reduced.
[0035]
According to this invention, it is possible to implement the apparatus having substantially the same processing capacity in the coagulation sedimentation tank of the invention of the first aspect, the treatment amount, and the quality of the treated water with a much smaller apparatus.
[0036]
The invention of claim 3 is that the floc growth tank of claim 1 or the floc production / growth tank of claim 2 has a larger horizontal cross-sectional area of the fining region located above the floc flow area than the horizontal cross-sectional area of the floc flow area. By providing, the ascending flow rate of the water to be treated in the clarification region is reduced so that the floc stirring flow in the flock flow region does not substantially reach the clarification region.
[0037]
Horizontal cross-sectional area (S₁ ) And horizontal cross-sectional area (S₂ ) Ratio (S₂/ S₁) Should be large, and in a preferred embodiment, S₂/ S₁= 1.1: 1 to about 2: 1, preferably about 1.2: 1 to 1.5: 1. If this ratio is 1.1: 1 or less, the amount of floc that rises in the clarification region increases, and the floc rises to a relatively large particle size, which is not preferable. On the other hand, if this ratio is 2: 1 or more, the horizontal cross-sectional area of the clarification area becomes large, leading to an increase in the size of the entire apparatus, or the horizontal cross-sectional area of the floc flow area becomes too small, and the amount of water flow (treated water volume). Is caused to cause a problem that cannot be increased.
[0038]
In this way, with a simple configuration set to increase the horizontal cross-sectional area of the clarification region compared to the flock flow region in which the flocs are agitated in the vertical direction, the fine flock rises from the clarification region and leaks to the outside. Can be sufficiently prevented.
[0039]
The invention of claim 4 is the invention of claim 3, wherein the floc growth tank or floc production / growth tank (hereinafter referred to as “floc growth tank etc.”) includes a common free water surface. And having a treated water outlet for discharging treated water linked to the free water surface so as to form a substantially one tank structure, and the inside of the one tank is an overflow wall and the flock growing tank etc. It is characterized in that the settling tank is partitioned and the horizontal cross-sectional area of the clarification area located at the upper part is larger than the horizontal cross-sectional area of the floc flow area.
[0040]
Here, the “substantially one tank structure” described above means that a part of the lower part in the tank of the structure surrounded by one tank peripheral wall (outer wall) is “a region where the flocs flow in the vertical direction”. The other means “area where flocs naturally settle and settle”. The upper part of the tank is divided into a part that is located at the upper part of the floc flow region and is affected by it, and a part that is laterally removed from the flock flow region and is hardly affected by it.
According to the present invention, in terms of mechanical structure, it can be formed so as to have two tank (partition) sections of a flock growth tank and a precipitation tank in one tank, and in particular, the precipitation tank has a narrow horizontal cross-sectional area ( Since it can be a small tank, the installation area of the entire apparatus can be reduced.
[0041]
According to a fifth aspect of the present invention, in the invention of the third aspect, the area of the free water surface of the floc growth tank or the like is covered by a shielding wall provided in water so that the area of the free water surface of the floc growth tank or the like It is characterized by being larger than.
[0042]
According to this 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 claim 4 above, but the upper part of the sedimentation tank area is shielded under the water surface, so that the isolation is You get higher. Needless to say, if a pressure gas is allowed to act on the upper part of the precipitation tank region where the upper part is shielded, a free water surface can be formed on the upper part of the precipitation tank.
[0043]
According to the invention configured in this manner, the same operation as that of the invention of claim 3 described above, that is, two tanks such as a floc growth tank and a precipitation tank can be formed substantially in one tank structurally. In particular, since the precipitation tank can be made into a tank with a narrower horizontal cross-sectional area, the installation area of the entire apparatus can be reduced, and the flock growth tank and the precipitation tank can be more clearly defined, so that the vertical direction in the flock growth tank There is an advantage that the setting of the stirring means for the stirring flow can be simplified or facilitated.
[0044]
The invention of claim 6 is characterized in that, in the invention of claim 1 above, a rectifying means is provided between the floc flow region of the floc condensation / growth tank and the clarification region above it. The invention according to claim 2 is characterized in that a rectifying means is provided between the floc flow region of the floc generating / growing tank and the clarification region above it.
[0045]
As the rectifying means, an appropriate one such as an inclined plate or a grating (mass-like plate) can be used. For example, a honeycomb-type inclined device type can be preferably used because the tank height can be lowered. Is done.
[0046]
According to these inventions, it is possible to satisfactorily suppress the transition of fine floc to the clarification region by the rectifying means between the floc flow region such as the floc growth tank and the clarification region, and to improve the quality of treated water. It is valid.
[0047]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
FIG. 1 is a diagram showing an example of a schematic configuration of a coagulation sedimentation apparatus according to the present invention. Raw water to be treated (hereinafter simply referred to as “raw water”) is supplied from a raw water supply pipe 1 to a coagulation tank 2 that is rapidly stirred. . In the middle of the raw water supply pipe 1, an inorganic flocculant addition pipe 3 is connected so that the inorganic flocculant is added to the raw water and line mixing is performed by a stirring means (not shown). 4 is a polymer flocculant addition pipe for supplying the polymer flocculant to the flocculant tank 2, and 5 is a sand addition pipe for supplying sand to the flocculant tank 2. The addition of the polymer flocculant and sand is selected so that the suspension (SS) is formed in the flocculation tank 2 at a position suitable for generating a condensed product (fine flock) containing sand. The
[0048]
201 is a stirring device provided in the coagulation tank 2, and the stirring blade 2011 is rotated by a motor 2012 at a predetermined stirring speed at which the sand supplied to the coagulation tank 2 is kept in a suspended state without being settled. Is done.
[0049]
In the coagulation tank 2 configured as described above, most of the suspension contained in the raw water supplied to the coagulation tank 2 is treated with sand, an inorganic coagulant and a polymer coagulant added. It becomes an aggregate (condensate) containing sand in water.
[0050]
Next, the water to be treated containing the aggregates is transferred to the floc growth tank 6 through the guide path 202 and slowly stirred by the overflow type. In this example, the guide path 202 is appropriately adapted to a flow in which a floc is fed from the agglomeration tank 2 in an overflow manner by the vertical partition wall, while the floc growth tank 6 agitates and flows to grow the floc. It is provided so as to open at a position where it can merge. The floc growth tank 6 of this example has a single tank structure that is substantially integrated with the subsequent precipitation tank 7, which will be described later.
[0051]
The floc growth tank 6 of this example is provided with a stirring device 601 having a propeller-shaped stirring blade 6011, and agglomerates contained in the water to be treated transferred from the aggregation tank 2 by a motor 6012. It is rotated so as to give an action of a stirring flow in the vertical direction at a predetermined stirring speed. Then, the agglomerates are agitated and flown within a predetermined height range (floc flow region: the region indicated by A in FIG. 1) by riding on the flow of the agitating flow in the vertical direction, so that the aggregates are aspirated. Growing frock. As a result, the floc has a large particle size and a large sedimentation speed. In the present example, the floc flow region is such that the flow rate of the water to be treated and the rotation of the stirring device are such that the floc flows from the bottom of the floc growth tank 6 to a height of about 3/4 of the tank height. Speed etc. are selected and set.
[0052]
Then, by generating the stirring flow as described above, a region in which substantially no flocs rise substantially above the floc flow region of the floc growth tank 6 (clarification region: region indicated by B in FIG. 1). In addition, an overflow trough 602 having a trough structure provided at the periphery is provided as an outlet for the treated water, and the treated water is drained.
[0053]
7 is a settling tank, and the water to be treated is introduced beyond the upper part of the overflow wall 8 between the floc growing tank 6 and the bottom is provided in an inverted conical shape. The floc (sludge) that has been removed is configured to be easily extracted from the top of the inverted cone. That is, when the transition water from the floc growth tank 6 including the floc is transferred and introduced into the sedimentation tank 7, the floc has a large sedimentation speed and thus quickly settles at the bottom of the tank. And it is extracted by the sludge extraction pump 702 through the sludge extraction piping 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 through a return pipe 703, and the sand separated from the sludge is supplied to the coagulation tank 2 from the above-described sand addition pipe 5. Recycling method is used. The sludge separated from the sand is discharged out of the system through the sludge discharge pipe 502.
[0054]
In this example, the upper end of the overflow wall 8 is set to be approximately 3/4 of the height of the floc flow region in the floc growth tank 6 described above, The influence of the stirring flow in the flow region is covered so as not to affect the inside of the precipitation tank 7. That is, the shielding wall 9 is formed by raising the vertical portion 902 upward along the overflow wall 8 from the vicinity of the bottom of the floc growth tank 6, thereby transferring transition water including floc from the bottom side of the overflow wall 8. A sedimentation tank is formed by a slant wall portion 903 that forms a water passage 901 that guides the upper end of the overflow wall 8 and that is continuous with the tank side wall under the water surface from a position above the upper end of the overflow wall 8. 7 is blocked except for communication through the water passage 901.
[0055]
Then, by providing the inclined wall portion 903 connected from the upper end of the vertical portion 902 rising along the overflow wall 8 to the side wall of the sedimentation tank 7, the floc growth tank 6 is horizontally extended from the floc flow area A to the clarification area B. In the clarification region B, the rising speed of the treated water is decelerated and the fine flocs are prevented from rising and shifting to the clarification region. Therefore overflowTrough 602Discharge of treated water fromTubeThe risk of direct leakage through the water will be greatly reduced, and highly purified treated water can be obtained.
[0056]
According to this example, the flock growth tank 6 and the sedimentation tank 7 partitioned by the overflow wall 8 and the shielding wall 9 can be provided in a tank having a single tank structure to constitute a small apparatus. In addition, this makes it possible to conveniently form a structure in which the horizontal cross-sectional area of the fining region of the floc growth tank 6 is made larger than that of the floc flow region, and to obtain treated water with excellent water quality with an apparatus having a small installation area. There is an advantage that can be.
[0057]
Moreover, smooth sludge extraction can be performed without affecting the sedimentation tank 7 due to the stirring flow in the floc flow region by the shielding wall 9.
Embodiment 2
The present example shown in FIG. 2 is characterized in that the shielding wall 9 is omitted and a grating type rectifying plate 10 that partitions the flock flow region and the clarification region is provided, compared to the first embodiment. The structure is substantially the same as that of the first embodiment. Therefore, the same components are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted.
[0058]
In this example, the overflow wall 8 functions to partition the floc growth tank and the sedimentation tank, and also has the effect of rapidly expanding the horizontal cross-sectional area in the clarification region as compared to the flock flow region. A relatively strong stirring flow is applied in the floc flow region so that the flocs exceed the upper end of the overflow wall 8. However, since the rectifying plate 10 is provided, the fine flocs are moved up and transferred to the clarification region. Is sufficiently suppressed.
[0059]
According to the apparatus of this example, substantially the same effect as that of the first embodiment can be obtained. Ie overflow wall8The more divided floc growth tank 6 and settling tank 7 can be provided in a single tank structure to constitute a small apparatus, and this allows the clarification area of the floc growth tank 6 to be horizontal. A configuration in which the cross-sectional area is made larger than that of the floc flow region can be conveniently formed, and further, since the rectifying plate 10 is provided, the rising and shifting of the fine flock to the clarification region can be further suppressed. Thus, treated water having excellent water quality can be obtained with an apparatus having a small installation area.
Embodiment 3
This example shown in FIG. 3 is characterized in that, in the apparatus of the first embodiment described above, an inclined plate-shaped rectifying plate 11 is provided to partition the flock flow region and the fining region, and the other structure is the embodiment. Same as 1. Accordingly, the same components are denoted by the same reference numerals as those in the first embodiment, and description thereof will be omitted.
[0060]
According to the apparatus of this example, the excellent effects of the first and second embodiments can be obtained at the same time. That is, the floc growth tank 6 and the sedimentation tank 7 partitioned by the overflow wall 8 and the shielding wall 9 can be provided in a tank having a single tank structure to constitute a small apparatus. In addition, this makes it possible to conveniently form a configuration in which the horizontal sectional area of the fining region of the floc growth tank 6 is made larger than that of the floc flow region.
[0061]
Further, the influence of the stirring flow in the floc flow region does not reach the sedimentation tank 7 by the shielding wall 9 and smooth sludge extraction can be performed.
[0062]
Furthermore, since the baffle plate 11 is provided, it is possible to further suppress the rising and shifting of the fine flock to the clarification region, and thus, it is possible to obtain treated water having excellent water quality with a device having a small installation area. .
Embodiment 4
FIG. 4 differs from the coagulation sedimentation apparatus of Embodiment 1 in the following points, but the other points are the same.
[0063]
That is, the tank configuration (the tank configuration having a coagulation tank, a floc growth tank, and a sedimentation tank) is the same, and the structure is also common in that the shielding wall 9 is provided.
[0064]
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 an inverted frustoconical shape in a cone shape from the peripheral wall to the bottom, thereby minimizing the dead zone where the flock may stay. To promote liquidity. Further, an inorganic flocculant is added to the flocculant tank 2, a polymer flocculant is added at a position where the guide path 202 faces the flock growth tank 61, and sand is further opened at the position where the guide path 202 in the flock growth tank 61 is opened. This embodiment is different from the first embodiment in that it is changed so as to be added.
[0065]
The difference from Embodiment 1 will be described. First, by making the bottom structure of the floc growth tank 61 into a cone shape, only the vertical floc flow stirring flow in the floc growth tank 61 provided by the stirring device 601 is used. There is an advantage that the dead zone that is likely to occur at the lower corner of the straight cylindrical tank can be eliminated by the structure of the tank.
[0066]
Further, in this example, the addition position of the polymer flocculant and the addition position of the sand are changed as described above, so that the flocculant tank 2 for adding the inorganic flocculant to generate the suspended solids, and this The effects of the floc growth tank 61 for growing the aggregate as flocs can be divided, and an advantage that a structure suitable for each action can be adopted is obtained.
Embodiment 5
This example shown in FIG. 5 is a modified example of the second embodiment (see FIG. 2), as in the relationship between the first embodiment (see FIG. 1) and the modified example 4 (see FIG. 4). The example which demonstrates the relationship which is is shown, the same code | symbol is attached | subjected about the structurally same member and structural part, and the description is abbreviate | omitted.
[0067]
According to the apparatus of this example, the effects of the second embodiment and the fourth embodiment can be obtained.
[0068]
That is, by making the bottom structure of the floc growth tank 61 into a cone type, a dead zone that is likely to occur at the lower corner of the straight cylindrical tank is generated only by the vertical floc flow stirring flow in the floc growth tank 61 provided by the stirring device 601. It can be eliminated by the structure of the tank. In addition, by making the addition position of the inorganic flocculant, the polymer flocculant and the sand the same as in the fourth embodiment, the action in the flocculation tank 2 for generating a coagulum and the floc growth tank for growing the coagulum as a flock. A structure suitable for each of the actions at 61 can be selected.
Embodiment 6
FIG. 6 shows an example of an outline of the configuration of another coagulating sedimentation apparatus of the present invention, and the water to be treated (raw water) is a floc growth tank 62 that is slowly stirred from the raw water supply pipe 1.To supplyIs done. Further, the inorganic flocculant is added to the raw water from the inorganic flocculant supply pipe 3 connected in the middle of the raw water supply pipe 1 and stirred by a line mixer to produce a condensed substance of SS and fine floc in the raw water. Yes. In this example, the flocculation tank 2 shown in Embodiments 1 to 5 is omitted, but this flocculation tank 2 is not essential in the practice of the present invention, and an inorganic flocculant in the middle of the raw water supply pipe 1 is used. It can be replaced by the addition of slag and line mixing, and the choice of either the formation of condensate in the piping or the formation of condensate by rapid stirring in the coagulation tank is the same as that of the SS contained in the raw water. It can be selected and used depending on the amount, nature, amount of treated water, or the installation area of the apparatus.
[0069]
Reference numeral 4 denotes a polymer flocculant addition pipe for supplying the polymer flocculant. In this example, as shown in the figure, an example is provided so as to add to the raw water supply pipe 1 near the end of the raw water supply pipe 1. Although shown, it can also be provided for addition to the floc growth tank 62. Reference numeral 5 denotes a sand addition pipe for adding sand to the vicinity of the raw water supply position below the flock growth tank 62.
[0070]
Reference numeral 201 denotes an agitation device provided in the flock growth tank 62, and the same one as in the first embodiment is used. As in the third and fourth embodiments, the floc growth tank 62 of the present example has a cone bottom structure provided in a cone shape, thereby increasing the fluidity of the floc and creating a dead zone where the flow at the lower lower corner of the tank is poor. It is provided not to form.
[0071]
7 is a sedimentation tank, and the treated water is introduced into the overflow beyond the upper part of the overflow wall 8 between the floc growth tank 62 and the bottom is provided in an inverted conical shape. It is provided so that sedimented and settled floc (sludge) can be easily extracted from the bottom of the inverted cone.
[0072]
Reference numeral 10 denotes a baffle plate installed over the respective upper portions of the floc growth tank 62 and the sedimentation tank 7, and divides the floc growth tank 62 and the precipitation tank 7 in comparison with the horizontal sectional area of the floc growth tank 62. Ascending flow in the clarification region where the influence of the stirring water flow in the flock flow region below the flock growth tank 62 is small due to the large horizontal cross-sectional area of the tank above the top of the overflow wall 8 (for example, 3/4 of the tank height) Is further stabilized, and there is an effect of further reducing the possibility that fine flocs are contained in the treated water discharged from the overflow trough 602.
[0073]
According to the flocculation / precipitation apparatus having the above configuration, most of the suspension (SS) contained in the raw water (treated water) is line-mixed in the raw water supply pipe 1 to which an inorganic flocculant is added. Then, the water to be treated containing the flocs is supplied to the floc growth tank 62, and is absorbed while being stirred and flowed in the floc flow area at the bottom of the tank together with the polymer flocculant and sand added at the same time. The flocs are combined to grow into large flocs and become flocs having a large particle size and a high sedimentation speed. The flocs contained in the treated water rising in the clarification region are settled downward due to the sedimentation properties, and flow into the upper part of the sedimentation tank 7. In this case, it settles rapidly and is extracted as sludge and returned to the cyclone 501, while the treated water is discharged from the overflow trough 602 through the current plate 10.
[0074]
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 single tank structure to constitute a small apparatus. The horizontal cross-sectional area of the clarified area 6 is made larger than that of the flock flow area..
[0075]
【The invention's effect】
As described above, according to the present invention, since the clear treated water is discharged from the floc growth tank, there is no need for a large area of water surface to overflow the discharged water in the settling tank. There is no need for a scraper that scrapes the sedimentation flocs at the bottom of the tank, and the sedimentation tank can be made smaller.
[0076]
In addition, from these facts, a large amount of water to be treated can be treated with an apparatus having a small installation area while the floc growth tank and the settling tank are substantially of a single tank structure.
[0077]
Further, the floc flow region in the floc growth tank can be agitated by using a propeller type agitating means in which a vertical flow occurs, and the influence of deterioration of treated water due to fluctuations in the flow rate of treated water flowing in is small. An apparatus can be provided, and processing at a high flow rate can be realized.
[0078]
Further, according to the invention of claim 2, by providing a rectifying means between the floc flow region and the clarification region of the floc growth tank, it is possible to further suppress the transfer of fine flocs to the clarification region. Thus, treated water with good water quality can be obtained.
[0079]
Furthermore, according to the invention of claim 5, since the adverse effect of the stirring flow in the floc flow region with respect to the transition water containing the floc moving from the floc growth tank to the sedimentation tank can be substantially eliminated, the sedimentation sludge can be discharged smoothly. Can be done.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of Embodiment 1 of a coagulation sedimentation apparatus of the present invention.
FIG. 2 is a diagram showing a schematic configuration of Embodiment 2 of the coagulation sedimentation apparatus of the present invention.
FIG. 3 is a diagram showing a schematic configuration of Embodiment 3 of the coagulation sedimentation apparatus of the present invention.
FIG. 4 is a diagram showing a schematic configuration of Embodiment 4 of the coagulation sedimentation apparatus of the present invention.
FIG. 5 is a diagram showing a schematic configuration of Embodiment 5 of the coagulation sedimentation apparatus of the present invention.
FIG. 6 is a diagram showing a schematic configuration of Embodiment 6 of the coagulation sedimentation apparatus of the present invention.
FIG. 7 is a diagram showing a configuration outline of an example of a conventional coagulation precipitation apparatus.
FIG. 8 is a diagram showing a configuration outline of another example of a conventional coagulating sedimentation apparatus.
[Explanation of symbols]
1 ... Raw water supply piping
2 ... Coagulation tank
201 ... Agitator
2011 ... stirring blade
2012 ... Motor
202 ... guide way
3 ... Inorganic flocculant added piping
4 ... Polymer flocculant-added piping
5 ... Sand added piping
501 ... Cyclone
502 sludge discharge pipe
6 ... Flock growth tank
601... Stirring device
6011 ... stirring blade
6012 ... Motor
602 ... Overflow trough
7 ... Precipitation tank
701 ... Sludge extraction piping
702 ... Sludge extraction pump
703 ... Return tube
8 ... overflow wall
9 ... Shielding wall
901 ... Water channel
902 ... Vertical portion
903 ... inclined portion
10,11 ... Rectifying plate
A ... Flock flow region
B: A clear region.

Claims (11)

Addition of sand and flocculant to the water to be treated, and agglomeration tank that agglomerates the suspension (SS) in the water to be treated in a state where the sand is suspended to generate flocs that are aggregates / aggregates containing sand. And a floc growth tank in which the floc transferred from the agglomeration tank is flown by a stirring flow in the vertical direction, and the floc growth tank is separated from the floc growth tank by an overflow wall, and the transition beyond the overflow wall A coagulating sedimentation apparatus comprising a sedimentation tank that settles flocs having a large sedimentation speed including sand contained in water and discharges the flocs outside the tank,
The floc growth tank has a floc flow region formed at the lower part in the vertical direction in the tank so that the flocs are stirred and flowed by the vertical stirring flow, and the vertical floc stirring flow by the stirring flow substantially extends. And a clarification region formed at the upper part of the floc flow region so as to have a treated water outlet for discharging treated water in association with the free water surface at the upper part of the clarification region, A coagulating sedimentation apparatus characterized in that the upper end of the overflow wall that divides the growth tank and the sedimentation tank is located below the upper limit of the floc flow region. Sand and flocculant are added to the water to be treated, and the suspension (SS) in the water to be treated is agglomerated in a state where the sand is suspended. A floc generation / growth tank that causes floc growth while flowing in a stirring flow, and a sedimentation that includes sand contained in the transition water that is separated from the floc aggregation / growth tank by the overflow wall and exceeds the overflow wall A coagulating sedimentation device comprising a sedimentation tank that sinks flocs of high speed and discharges them outside the tank,
The floc generation / growth tank has a floc flow region formed at the lower part in the vertical direction in the tank so that the floc is stirred and flowed by the vertical stirring flow, and the vertical floc stirring flow by the stirring flow is substantially A clarification region formed at the upper part of the floc flow region so as not to reach the upper surface of the floc flow region, and a treated water outlet for discharging the treated water in association with the free water surface at the upper part of the clarification region, and The coagulation sedimentation apparatus characterized in that the upper end of the overflow wall that divides the floc producing / growing tank and the sedimentation tank is located below the upper limit of the floc flow region. The floc growth tank of claim 1 or the floc production / growth tank of claim 2 increases the flow rate of the water to be treated in the clarification region by increasing the horizontal sectional area of the clarification region as compared to the horizontal sectional area of the flock flow region. The coagulation sedimentation apparatus according to claim 1 or 2, wherein the floc stirring flow in the flock flow region is substantially reduced so as not to reach the clarification region. The floc growth tank or floc generation / growth tank and the sedimentation tank according to claim 3 have a common free water surface and a treated water outlet that discharges treated water in association with the free water surface. A clarified region located above the horizontal cross-sectional area of the floc flow region by forming two tanks and dividing the floc growth tank or floc generating / growing tank and the settling tank by an overflow wall inside the one tank A coagulating sedimentation apparatus characterized by having a large horizontal cross-sectional area. 4. The horizontal cross-sectional area of the floc flow region is defined as the area of the free water surface of the floc growth tank or floc generation / growth tank by covering the upper part of the sedimentation tank from the upper end of the overflow wall with a shielding wall provided in water. A coagulating sedimentation apparatus characterized by being larger than the above. 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 growth tank. 6. The coagulating sedimentation apparatus according to claim 2, wherein a rectifying means is provided between the floc flow region of the floc producing / growing tank and the clarification region on the upper portion thereof. 8. The coagulating sedimentation apparatus according to claim 1, wherein an upper end of the overflow wall is set within a range of 1/2 to 4/5 of a height of the floc flow region. In Claim 1, while connecting the piping which adds the inorganic flocculant for condensing the suspension in to-be-processed water in the middle of the supply piping which supplies this to-be-processed water to a coagulation tank, an inorganic flocculant addition position A coagulating sedimentation apparatus characterized in that a stirring means is installed in the pipe downstream of the coagulating tank, and a polymer coagulant contributing to the growth of coagulated floc and sand are added to the coagulating tank. The polymer flocculant and sand which contribute to the growth of flocs according to claim 2, wherein a coagulation tank to which an inorganic flocculant for condensing the suspension in the water to be treated is added is provided in the front stage of the floc generation / growth tank. The coagulating sedimentation apparatus is characterized in that the addition position is provided at or near the transfer position of the water to be treated from the condensation tank to the floc generation / growth tank. In Claim 2, while connecting the piping which adds the inorganic flocculent for condensing the suspension in to-be-processed water in the middle of the supply piping which supplies this to-be-processed water to a flock production | generation / growth tank, inorganic aggregation A stirrer is installed in the pipe downstream of the agent addition position, and the addition position of the polymer flocculant and sand that contributes to the growth of flocs is at or near the introduction position of the water to be treated in the floc generation / growth tank. A coagulating sedimentation apparatus characterized by being provided.

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