JP2000117005A - Flocculating and settling method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate water and floc by growing a high density floc binding a suspended substance(SS) and sand and having uniform and averaged particle size in order to remove the SS in raw water. SOLUTION: At the time of executing the floc forming treatment in which the floc containing the sand is grown while circulating and fluidizing the water to be treated containing the SS and to which a flocculating agent and the sand having high specific gravity are added in the tank and the settling treatment in which the floc containing the sand and grown so as to have high settling speed is settled and separated from the water by transferring the water to be treated to a settling and separating tank 2 from a floc forming treatment tank 1 by overflowing on an overflow wall 201, deposited floe is fluidized by lifting by upward stream by making the water to be treated to flow by the upward stream in the floc forming treatment tank 1 from its bottom part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for coagulating and sedimenting a suspension (SS) in water to be treated. And a method and apparatus for removing SS efficiently, which precipitates the suspension as an aggregate having a high sedimentation rate.

[0002]

2. Description of the Related Art As a coagulation sedimentation method for removing fine suspended solids (SS) in water to be treated, a method and apparatus for rapidly sedimentation and sedimentation by flocculation of SS and floc growth are disclosed in, for example, France Patent No. 1411172, French Patent No. 1501912 (filed on Sep. 28, 1969), French Patent No. 2071027 (January 1, 1969)
(Filed on February 16), Japanese Patent No. 2634230,
It is proposed in Japanese Patent Application Laid-Open No. 8-47606.

In this method, fine suspended particles that cannot be separated at high speed by natural sedimentation in a stock solution are chemically treated with insoluble and high-density sand particles (hereinafter collectively referred to as “sand”). Using flocculant, aggregate containing SS (flock)
The sediment is made into high-density agglomerates (flocs) that sediment easily and sediments from the water to be treated.

[0004] According to this method, when sedimentation and separation are performed by a general coagulation sedimentation method, the floc has a low density of about 1.01 to 1.02 and a low sedimentation speed, so that treatment at a high flow rate cannot be performed. In comparison, since the floc contains sand having a density of about 2.7, a large sedimentation velocity is obtained, and the floc can be sedimented promptly while flowing the water to be treated at a high flow rate. If the advantage is that the processing flow rate per unit time can be increased,
It is considered to be advantageous in that the device scale can be reduced.

[0005] The principle configuration of the apparatus for carrying out this method is, for example, a flocculation tank in which an inorganic flocculant and a polymer flocculant are added to raw water and stirred, and flocs which are flocculated into small particles by the flocculation tank are large. A floc forming tank for growing into flocs, a sedimentation tank in which flocs having a large sedimentation rate including sand grown in the floc forming tank are settled and settled on the tank bottom, and treated water overflows from the tank upper part as supernatant water to be separated. It is configured as a one-pass circulation type processing tank equipment provided with each tank in order. The raw water (water to be treated) flowing into the treatment tank equipment is provided with a stirring state and a flow rate suitable for the respective treatments in the coagulation, floc formation and sedimentation tanks (see FIG. 5).

However, the technique of the method is not widely used in practice. This is because some important problems have not yet been solved for application to practical industrial scale equipment.

One of the problems is not only the above-mentioned method but also the case where SS is to be coagulated and removed by the coagulation sedimentation method, but the floc having a uniform size and uniform density is used. It is difficult to generate the floc, but rather, the sedimentation velocity of the floc tends to be widened largely as a result of the generation of a substance having a high sedimentation velocity due to the addition of sand.

[0008] That is, the growth of floc is caused by fluctuations in the water quality of the water to be treated, types and amounts of various chemical treatment agents to be added, dispersion of sand and the like, SS presence, local changes in flow velocity. Because of the influence of various fluctuation factors such as the above, it is inevitable that the distribution of the sedimentation velocity of each floc that is generated and grown widens. In other words, even if a floc is generated under the same conditions when viewed from a macro (macroscopic), a large number of generated flocs have a diameter of about 1 to 4 mm when viewed from a micro (microscopic). While some are large and have a large amount of sand involved, the sedimentation velocity can reach 15 to 1000 m / h, while the diameter is as small as about 100 to 200 μm and not combined with sand or only a small amount of sand. Because they are not bonded, fine flocs having an extremely slow sedimentation speed of about 0.5 to 2 m / h also exist, and a large number of fine flocs are contained in the water to be treated passing through each tank in one pass. A large amount flows into the separation tank.

In order to prevent such fine flocks from flowing out, for example, in the method described in the above-mentioned Japanese Patent No. 2,634,230, as shown in FIG. 5, a separating plate is provided above the floc sedimentation tank, and Has proposed to use a separation plate to capture fine flocs that overflow in the treated water.

[0010]

The method of installing the separation plate is effective in that fine flocs contained in the overflowing treated water (supernatant water) can be reduced, but on the other hand, a separation plate is required. There is a disadvantage in terms of installation equipment. In addition to this, the burden on maintenance and inspection of the separation plate, where clogging is unavoidable, is large, running costs are increased, and measures to temporarily stop the device to recover from clogging of the separation plate, In particular, there is a problem that it is necessary to temporarily store treated water (or raw water) when the apparatus is stopped in equipment requiring continuous operation.

By the way, as shown in the example of FIG. 5, in order to form the formed flocks with sand as much as possible and having a large particle size and a high density, the transition from the floc forming tank to the sedimentation tank is performed. It is better to go over the top of the board. This is because if a transfer port to the sedimentation tank is provided at the lower part of the floc formation tank, the high density flocs containing sand move quickly to the sedimentation tank, and only the relatively light density flocs remain in the floc formation tank. This causes a problem that the reaction time required for floc formation is prolonged. According to the method of shifting over the upper portion of the overflow plate, the floc concentration is maintained high in the floc forming tank, increasing the chance of contacting the fine floc generated by the aggregation of the inorganic flocculant, increasing the sedimentation speed. A large floc can be grown, the reaction time required for floc formation can be shortened, and the floc forming tank can be downsized.

However, in the method in which the floc is transferred to the sedimentation tank over the upper part of the overflow plate, particularly large flocs having a large particle diameter and sand not absorbed by the floc settle on the bottom of the floc formation tank. There is a difficulty of doing it. This problem, as shown in FIGS. 6 and 7, results in partly in the accumulation of large particle size flocs at the bottom of the floc forming tank, and in other cases, this type of equipment usually has a sedimentation tank. The sand is separated from the sludge collected in the above, and is recycled by recirculation so as to be added to the flocculation tank again.However, the amount of the sand to be reused becomes insufficient, and the floc having the desired density is not formed. This is described as a problem that the formation of flocs having a low density is caused, and the flocs leak into the treated water in the sedimentation tank, causing a problem that the treated water is deteriorated. It is thought that this shortage of sand can be solved by adding a shortage of sand from the outside.However, this would lead to an increase in sand addition equipment and operating costs, When the flow state fluctuates due to changes in water temperature, the accumulated floc and sand flow and return to the circulating flow of the floc forming tank, and the balance of the amount of sand circulating in the system changes, In addition, there is a possibility that problems such as deterioration of reactivity due to a short path or the like due to the reduction of the flow path and decay of the deposited floc may occur, resulting in a failure in stable operation.

In order to eliminate the problem of heavy flocs accumulating in the floc forming tank in the above overflow method, it is conceivable to perform strong stirring in the floc forming tank. This causes a problem that the particle size of the floc is reduced, the sedimentation speed is reduced, and the upward flow in the sedimentation tank cannot be set to a high flow rate. From these facts, it is necessary to satisfy the trade-off requirement that floc destruction should be avoided as much as possible while preventing floc sedimentation and accumulation in the floc formation tank. Not. For example, an intermediate tank is provided between a floc forming tank and a sedimentation tank, and in the floc forming tank, sedimentation of sand and large density flocs is prevented by relatively strong stirring, and flocs are grown by weak stirring in the intermediate tank. Although it is conceivable to shift the process from to a precipitation tank, this method requires an increase in the number of tanks, an increase in equipment costs due to an increase in stirrers, an increase in operation costs, an increase in installation area, and the like. Is not advantageous.

The inventor of the present invention has made the present invention based on the facts found during intensive studies in order to solve the various problems of the prior art described above.

That is, the present invention relates to a method for preparing a suspended substance (S) in raw water.
In order to remove S), a technique based on combining SS and sand to grow high-density floc is generally not necessarily uniform (settling speed depending on size, density, etc.). It is an object of the present invention to reduce as much as possible the problem that no floc is generated.

Another object of the present invention is to make it possible to realize a method capable of increasing the processing flow rate by generating flocs containing sand with a facility as simple and small as possible. It is intended to provide a method and an apparatus for removing flocculated sediment of SS in raw water which can be widely spread as a method.

[0017]

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

That is, according to the present inventors' intensive studies to solve the above-mentioned various problems, it has been found that large flocks and sands having a high density can be smoothly and sufficiently circulated and flow in a floc forming tank. It has been found that it is important to transfer the water to be treated from the inside of the floc forming tank to the settling tank by the overflow method. In other words, by the former configuration, by performing flow circulation that prevents sedimentation and accumulation at the bottom of the floc forming tank of heavy large flocs, the chance of absorbing fine flocs to the large flocs that circulate can be increased. Therefore, it is effective to reduce the fine floc transferred to the sedimentation tank, and by adopting the latter overflow type transfer method, only the large floc is quickly transferred to the sedimentation tank and fine floc is reduced. It is possible to prevent the problem that the reaction time required for floc formation is prolonged due to being left behind. From such a viewpoint, the invention of each claim of the present application employs a configuration capable of exhibiting a flow promoting action suitable for circulating and flowing while winding up so that large flocs do not settle and deposit in the floc forming tank. It is characterized by having done.

According to the first aspect of the present invention, there is provided a method for coagulating and sedimenting a suspension, comprising treating a water to be treated containing a suspension (SS) and adding a chemical treating agent necessary for floc formation and insoluble fine particles having a large specific gravity. A floc forming process for growing flocs containing insoluble fine particles while circulating and flowing in the inside; and a sedimentation process for separating flocs grown so as to have a large sedimentation velocity containing the insoluble fine particles by the above process, from water. A method of flocculation and sedimentation in which each of the treatments is performed sequentially in such a manner that water to be treated continuously moves on an overflow plate that separates a tank for floc sedimentation separation from a tank for floc formation treatment. The flow of the water to be treated in the tank for performing the floc formation treatment is such that the floc that settles at the bottom by flowing the water to be treated upward from the bottom of the floc formation tank into the upward flow. Ri wound up, characterized in that so as to flow.

In the above structure, sand (specific gravity of about 2.7) is generally used as the "insoluble fine particles" having a large specific gravity, and the particle size is generally, but not limited to, 10 to 2 particles.
Those having a thickness of about 00 μm, preferably about 50 to 200 μm are preferred. In the following description, the insoluble fine particles will be represented by sand.

The sedimentation velocity v of particles such as sand in a fluid is expressed by the following Stokes equation: v = g (ρs−ρ) d ² / μ / 18 (where ρs: density of particles, ρ: density of water, d: particle diameter, μ: viscosity coefficient of water, g: gravitational acceleration). If a substance having too large specific gravity and particle diameter is used, sand will settle without adsorbing to the floc in the floc forming tank. Sand having the above-mentioned particle size range is suitable because the proportion of such particles increases.

As the "chemical treatment agent" required for floc formation, polyaluminum chloride (PA) is generally used.
C) An inorganic coagulant such as ferric chloride or ferric sulfate is used in combination with a polymer coagulant such as an anionic polymer coagulant or amphoteric polymer coagulant. The inorganic coagulant is a suspension (S
It is used for aggregating S) and sand, and a polymer flocculant is used for growing these aggregates into large flocs.

The method of adding these sand and flocculant is as follows.
It is performed by adding the floc to the tank for the floc formation treatment, but the inorganic coagulant may be added in the middle of the introduction pipe of the water to be treated. Further, a flocculation treatment tank with strong stirring for adding an inorganic coagulant may be provided in a stage preceding the floc formation treatment tank.

The suspended state of flocculation and floc growth in the floc forming tank is provided by generating a circulating flow with a swirler or a stirrer, for example, to such an extent that sand having a large specific gravity does not settle. .

The floc sedimentation tank for sedimenting the floc containing sand and separating it from the water is configured to transfer the water to be treated by a flow from the floc formation treatment tank over the upper portion of the overflow plate. The floc contained in the water to be treated introduced into the sedimentation separation tank quickly sediments at the bottom of the sedimentation tank due to its large particle size and large density. As a result, most of the suspended solids (SS) contained in the water to be treated are contained in the settling flocs and separated from the water. On the other hand, water is discharged from the upper part of the settling tank to the outside, for example, in the form of overflow. At this time, fine flocs that flow to the upper side of the sedimentation tank together with water without sedimentation may be captured by passing through a filler-filled layer or the like provided on the upper side of the sedimentation tank. Even if a filler packed bed is used in the present invention, fine flocs are absorbed and grow while the flocs and the like circulate and flow in the floc forming treatment tank in the circulating flow of the to-be-processed water. There are few fine flocks flowing into the tank and the burden of clogging is small. As such a filler-filled layer, for example, a large number of fillers (contact materials) are randomly accumulated, thereby partially restricting the upward flow and forming stagnation on the back side of the flow of the filler.
It is preferable to employ a material that causes the fine flocs to stay in the stagnation portion and performs a filtering action such as growth and sedimentation and aggregation of the fine flocs. Such a filler-filled layer has, for example, a diameter of 4
It can be formed by randomly collecting plastic short tube-shaped pieces having a length of about 15 mm to about 12 mm as a filler, but is not particularly limited thereto. It is also possible to use a filler in which a large number of holes are formed in the spherical surface of a hollow sphere, a teralet packing, or the like. In addition, since this filler-packed layer needs to function as a water passage for passing an upward flow at a high flow rate, it forms a stagnation portion for the upward flow while having a porosity as high as possible as a whole layer. For this purpose, a filler having a size and shape capable of having a large surface area is preferably selected and used.

The floc settled at the bottom of the sedimentation tank is discharged out of the apparatus by a drawing means such as a sludge drawing pump, and if necessary, the above-mentioned Japanese Patent Nos. 2634230, 9847606 and 9-141006. As described in the publication, sand can be separated from the extracted sludge using a separator such as a cyclone and reused.

The most significant feature of the present invention is that water to be treated introduced into a tank for floc formation treatment is allowed to flow upward from the bottom of the tank to generate a circulating flow therein. is there. As a result, the floc settling at the bottom is taken up by the circulating flow, and while maintaining a high flow rate, the suspended matter (SS) contained in the water to be treated is absorbed with the added sand to grow into flocs having a large particle size. As a result, the amount of fine flocs flowing into the precipitation separation tank can be reduced.

According to the present invention, for example, 50 to 150 m /
While the water to be treated is passed at a high flow rate of h, most of the suspended solids (SS) in the water to be treated are flocs having a large particle diameter and a large sedimentation velocity, and are quickly settled in the sedimentation tank. be able to.

According to a second aspect of the present invention, there is provided a method for flocculating and suspending a suspension, wherein a circulating flow of winding up floc settling at the bottom of the tank for floc formation treatment is generated from the bottom of the tank. Instead of inflowing upwards,
The circulating flow of the water to be treated is set to flow in one direction along the flow path defined by the partition walls in the tank for the floc formation treatment, and the circulation is performed from a downward flow to an upward flow at the bottom of the tank. It is characterized in that the flowing stream is turned and flows so that the floc settling at the bottom of the tank is wound up.

In the above configuration, the circulating flow flowing in one direction in the passage formed by the partition wall can be generated using, for example, one or a plurality of swirling blade devices.

According to the present invention, a recirculating flow including an upward flow that rises inward or outward from the bottom of the tank can be generated in the tank of the floc forming process, and the flocs that settle to the bottom can be wound up. Since flocs can be grown greatly by absorbing SS and sand without causing sedimentation and accumulation of flocs in the floc forming tank,
For example, it is possible to carry out a treatment in which the outflow of the fine floc from the sedimentation / separation tank is suppressed while passing the water to be treated at a high flow rate of 50 to 150 m / h.

According to a third aspect of the present invention, there is provided a method having both of the above methods. According to the present invention, a circulating flow is promoted by introducing water to be treated in an upward flow from the bottom of the tank.
Combined with the rectification of the circulating flow by the partition wall installed in the tank and the promoting action of the swirling blade device, etc., the circulating flow in the tank of the floc forming process is further stabilized, and the floc having a large particle diameter and a large sedimentation velocity is formed. The amount of fine floc that grows well and transfers to the sedimentation separation tank can be reduced.

According to a fifth aspect of the present invention, in each of the above-mentioned inventions, the upward flow velocity of the fluid circulating flow provided to the bottom of the floc forming tank is 50 m / h or more, preferably 200 m / h.
/ H or more.

According to the present invention, the coagulation / sedimentation treatment can be performed at a higher flow rate than in the prior art, and a large amount of raw water (water to be treated) can be treated with a small-scale facility.

According to a sixth aspect of the present invention, there is provided an apparatus for coagulating and precipitating a suspension, comprising treating a water to be treated containing a suspension (SS) and adding a chemical treating agent necessary for floc formation and insoluble fine particles having a large specific gravity. A floc forming tank for growing flocs containing insoluble fine particles while circulating and flowing in the tank; and a tank in which the flocs containing insoluble fine particles grown by the above-described treatment and having grown so as to have a high sedimentation velocity are settled at the bottom of the tank and separated water is applied to the tank. An overflow type in which the floc sedimentation tank discharged from the upper part and the transfer of the water to be treated from the floc formation tank to the floc sedimentation tank flow over the upper part of the overflow plate provided to partition both tanks. A coagulating sedimentation apparatus having a flow path, wherein a treated water introduction pipe for allowing treated water to flow in an upward flow is connected to the bottom of the floc forming tank.

In the above configuration, the flock forming tank may be of various types, such as a cylindrical cross section, a rectangular section, or a combination of a curve and a straight line (for example, a combination of a semicircle and a rectangle). However, the structure can be determined from the flow rate of the water to be treated in the floc forming tank, the flow rate of the overflow water determined by the cross-sectional area of the overflow type flow path, and the like.

The method of discharging from the upper part of the precipitation tank is as follows.
Although not limited, an overflow type using a gutter having an overflow weir is often preferred because of its simple structure.

According to the present invention, the flow of the to-be-processed water flowing and circulating in the floc forming tank can be given by the introduction of the raw water, and the large flocs which are easily settled on the bottom are rolled up with the introduced water. The risk of flocks settling on the bottom is greatly reduced or eliminated.

In a seventh aspect of the present invention, there is provided an apparatus for coagulating and sedimenting a suspension, comprising treating a water to be treated containing a suspension (SS) and adding a chemical treating agent necessary for floc formation and insoluble fine particles having a large specific gravity. A floc forming tank for growing flocs containing insoluble fine particles while circulating and flowing in the tank; and a tank in which the flocs containing insoluble fine particles grown by the above-described treatment and having grown so as to have a high sedimentation velocity are settled at the bottom of the tank and separated water is applied to the tank. An overflow type in which the floc sedimentation tank discharged from the upper part and the transfer of the water to be treated from the floc formation tank to the floc sedimentation tank flow over the upper part of the overflow plate provided to partition both tanks. A flocculating sedimentation device having a flow path, wherein the floc forming tank has a vertical flow path for upward flow and a vertical flow path for downward flow in the tank. Vertically extending flow path A partition is provided, and a flow promoting means for circulating and flowing the water to be treated from one of the vertical flow paths to the other vertical flow path is provided, and the flow of the lower part of the partition is changed from a downward flow to an upward flow. A water circulation diversion unit is provided near the bottom of the tank.

In the above configuration, the flow path setting partition for partitioning the upward flow and the downward flow is generally formed by a substantially vertical plate, but is not limited to this vertical plate. Can be provided in combination with an inclined plate or the like so as to be suitable for the circulation of flocs.

The flow promoting means can be constituted by using a swirling blade device, a stirrer or the like.

According to the present invention, since the vertical flow paths of the upward flow and the downward flow are defined by the flow path setting partition, the circulating flow flowing through each of these flow paths promoted by the flow promoting means. The flow is rectified to reduce the risk of destruction of flocs,
The effect is achieved that the absorption of SS, sand or fine floc is performed well.

According to an eighth aspect of the present invention, in the apparatus provided with the flow path setting partition, the overflow type flow path is provided in an overflow plate and a sedimentation tank to introduce overflow water downward into the sedimentation tank. It has a guide wall for guiding.

According to the present invention, since the direction of the flow of the water to be treated which flows into the settling tank over the overflow plate is guided downward, the tendency of the floc to settle and settle is increased, and at the same time, the small floc is settled. The effect of suppressing the tendency of water to flow to the overflow device side can be obtained.

According to a ninth aspect of the present invention, in the apparatus provided with the flow path setting partition, the overflow plate and overflow water distribution guide walls provided respectively in the floc forming tank and the settling tank on both sides of the overflow plate. As a result, the overflow water distribution guide wall on the side of the floc forming tank is suspended from the water surface into the water, and faces the floc forming tank at the middle position in the vertical direction of the floc forming tank. It is characterized in that it is provided so as to form a treated water inflow opening.

Typically, the above-described structure includes an overflow plate located below a certain depth from the water surface between partition walls (overflow water distribution guide walls) that partition both tanks suspended in water from above the water surface. The configuration provided can be exemplified, and in this way, the bulkheads enter into a vertical meandering (labyrinth-like) shape, and the upward / overflow / downward (flow into the sedimentation tank) large-flock smoothly. The effect of quickly accelerating the sedimentation and reducing the tendency of the fine floc to move to the water surface side can be obtained.

According to a tenth aspect of the present invention, in the apparatus provided with the above-mentioned flow path setting partition, the flow path setting partition provided in the floc forming tank is a vertically open cylindrical wall installed in the floc forming tank. And a flow promoting means for promoting the circulating flow is provided inside the cylindrical wall.

According to the present invention, an up-down flow is circulated in the substantially double cylindrical floc forming tank between the flow path inside the inner cylinder and the flow path between the inner cylinder and the outer cylinder. This flow can be promoted by a flow promoting means such as a swirling vane device and the like, so that a rectified flow can be formed as a whole, and it is possible to favorably wind up flocks and grow flocs.

According to an eleventh aspect of the present invention, in the apparatus provided with the above-mentioned flow path setting partition, the floc forming tank is provided in the first vertical direction for the vertically long upward flow set by the flow path setting partition. A flow path, and a second vertical flow path for a vertically short downward flow biased toward the upper side of the first vertical flow path and defined by a flow path setting partition, The second vertical flow path is connected to the settling tank via the overflow type flow path, and the lower part of the second vertical flow path returns the floc to the first vertical flow path so that it can be circulated. It is characterized by being communicated.

According to the present invention, the portion forming the second vertical flow path for the downward flow has a role as an intermediate tank before the transfer of the water to be treated to the settling tank. Flock that may be deposited on the bottom of the flow path of the portion can return the flock to the first vertical flow path having the function of winding up the floc in the upward flow, so that the floc is prevented from being destroyed, Can be satisfactorily wound up.

According to a twelfth aspect of the present invention, there is provided a construction in which a treated water introducing pipe for flowing treated water in an upward flow from the bottom of the floc forming tank is connected, and the circulating flow is supplied to the floc forming tank in the tank. And a flow path setting partition for flowing in one direction is provided.

According to the present invention, the circulating fluid flow that is turned from the downward flow to the upward flow can flow smoothly at the bottom of the floc forming tank, and the breakage of the floc can be suppressed.
The flock can be satisfactorily wound up.

According to a thirteenth aspect of the present invention, in each of the above-described device inventions, the floc forming tank is provided in a cone shape in which the shape near the tank bottom is such that the horizontal cross-sectional area decreases from the top to the bottom. And

According to the present invention, since the horizontal cross-sectional area is small at the bottom of the floc forming tank for winding the flocks, the flow velocity can be increased to increase the hoisting force, and therefore, the flocks can be more effectively prevented from being deposited. Is obtained.

As the raw water (water to be treated) to which the present invention is applied, for example, industrial water, river water, industrial wastewater and the like can be typically mentioned.

[0056]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 In the present embodiment shown in FIG. 1, a floc having a high density settled and deposited on the bottom of a floc forming tank 1 is introduced into the tank 1 of raw water (water to be treated). Fig. 2 shows an example of an apparatus in which the film is wound by the force of a stream.

In FIG. 1, reference numeral 1 denotes a flock forming tank. The tank wall structure forming the outer shell of the tank main body has a body portion 101 having a vertical cylindrical shape on the upper side, and a horizontal sectional diameter gradually decreases toward the bottom. It has a lower cone portion 102 and an opening 104 provided below an upper partition 103 that forms a part of the body 101 as an overflow water distribution guide wall. The opening 104 allows the partition 103 and the next settling tank 2 to be formed. It is provided so that the water to be treated is transferred to the settling tank 2 in an overflow manner through a space between overflow walls 201 formed as partial side walls. The upper body 101 is formed by combining a semi-cylindrical part on the left side of the figure and a rectangular part on the right side of the figure when viewed in a horizontal plane. An opening 104 for communicating with the upper partition 10 forming the opening 104
3 are provided.

The cone portion 10 of the floc forming layer 1
A raw water introduction pipe 3 is connected to the bottom of the tank 2 so that the raw water is introduced upward into the tank 1, and at a substantially central position of the tank 1, a circulation flow promoting pipe is provided. Is installed so as to be suspended from above the tank 1,
Turning blades 402 and 403 rotated by a motor 401
This promotes the circulation flow that is upward at the center position of the tank 1 and downward near the inner wall of the tank. 404
This is a rotating shaft on which the swirling blades 402 and 403 are assembled.

Reference numeral 5 denotes an inorganic coagulant supply pipe, which is connected in the middle of the raw water introduction pipe 3 so as to add the inorganic coagulant to the raw water. Numeral 6 denotes a polymer flocculant supply pipe, from which the polymer flocculant is added into the floc forming tank 1 from the side of the cone 102. Numeral 7 denotes a sand supply device, which returns sludge drawn out from the bottom of the sedimentation tank 2 by a pump 701 to a cyclone 702, separates sand from flocs by the cyclone 702, and treats water to be treated in the floc formation tank 1 with the sludge. To be added from above the water surface. The SS and the like other than the sand separated by the cyclone are discharged as sludge by the sludge discharge pipe 703, and are subjected to predetermined treatment and disposal.

The floc containing the SS in the raw water together with the sand is passed through the overflow wall 201 and introduced into the sedimentation tank 2 through the floc forming tank 1 having the above-described structure. The structure of the tank body of the sedimentation tank 2 has a structure similar to that of the floc forming tank 1, and includes a vertical cylindrical body 202 on the upper side and a lower side whose horizontal cross-sectional diameter gradually decreases toward the bottom. It has a cone section 203 and an overflow device provided with an overflow gutter 204 through which the treated water overflows around the upper part of the tank. The (treated water) is discharged from the overflow gutter 204 to the outside. Numeral 205 denotes an overflow water guide wall which guides the flow of the water to be treated, which has flowed into the sedimentation tank 2 over the overflow wall 201, in a downward direction. Acts to increase the tendency to settle and, at the same time, to suppress the tendency of the flocs to flow to the overflow device side.

The operation obtained by the coagulation and sedimentation apparatus of the present embodiment constructed as described above will be described. Generally, large flocs having a large particle diameter and a high density are deposited and deposited at the bottom of the floc forming tank 1. However, in the apparatus of the present embodiment, the bottom of the tank 1 is formed as a cone 102 and is limited to a region having a relatively small horizontal cross-sectional area. Since the raw water is introduced into the raw water in the upward flow, the large flocs that have accumulated or are about to be deposited in the same portion are taken up by the upward flow of the raw water. Since the diameter of the cone portion 102 of the tank 1 gradually increases upward, the force of winding up the floc by the above-mentioned introduced raw water flow becomes small if it is unchanged, but in this example, it is necessary to further promote this. Since the swirling blade device 4 is provided, the upward movement of the flock along the substantially center position of the tank 1 is promoted.

The force of the upward upward flow that winds up the large floc formed along the center line of the tank 1 gradually decreases toward the upper cylindrical body portion 101 having a large horizontal cross-sectional area. Turning to a downward downward flow while diffusing to the inner peripheral wall side. Therefore, the large floc riding on this flow also rises along the center line from the bottom side of the tank 1 and circulates in the tank 1 on the flow which turns to a downward flow toward the upper side of the tank 1. This circulation is promoted by the inflow position (bottom portion) and direction (upward) of the raw water and the swirling blade device 4 described above.

On the other hand, the very fine flocs and SS in the raw water to which the inorganic coagulant has been added before the introduction into the tank 1 and the high-molecular coagulant get on the circulating flow. The opportunity for contact to be absorbed by the flocks on the vehicle is sufficiently provided. Further, sand supplied from above the water surface of the tank 1 also has a sufficient contact opportunity to be sucked into the circulating flocs.

The body 101 of the floc forming tank 1
The water to be treated flows constantly and continuously from the opening 104 to the overflow channel provided at a predetermined position and height at the predetermined position and height so as to move to the settling tank 2 side. As a result, a large proportion of the large flocks are transferred to the settling tank 2.

Therefore, according to the present example apparatus, by specifying the inflow position and direction of the raw water and the swirling blade device 4,
Since the circulating flow in the floc forming tank 1 is promoted, the problem that large flocs precipitate and accumulate in the floc forming tank 1 is eliminated, and there is no need to apply extremely strong agitation, thereby reducing the risk of breakage of the flocs. Or be resolved. In addition, SS in the raw water and fine flocs containing the same are provided with a sufficient opportunity to come into contact with larger flocs in the middle of the circulating flow. And the prevention of leakage of fine floc from the sedimentation tank is effectively achieved. Also, when a separating plate or the like is provided on the upper part of the settling tank, the time required to close the separating plate is significantly longer than that of the conventional example, which is extremely useful for reducing the burden of maintenance and inspection to cope with this. is there.

Embodiment 2 In the present embodiment shown in FIG. 2, as in Embodiment 1 described above, large flocs having a large density settled and deposited on the bottom of the floc forming tank 11 are transferred to the raw water (treatment water) tank 11. In addition to this, there is provided an apparatus having a guide wall (flow path setting partition) for further promoting the circulating flow of the water to be treated in the floc forming tank 11 in addition to the characteristic of being wound up by the force of the introduction flow. Is shown.

A structural feature of the apparatus of this embodiment lies in the structure of the floc forming tank 11. That is, the tank wall forming the outer shell structure of the tank 11 has a lower cone portion 113 whose diameter gradually increases upward from the bottom with a narrow horizontal cross-sectional area, and a vertical cylindrical shape from the upper end of the cone-shaped lower portion. The middle trunk 11 which stood up above
2 and an upper torso 1 that continues further upward from this intermediate torso
It consists of 11. And this upper body 111 is
A semi-cylindrical portion and a rectangular portion are combined in a horizontal plane substantially in the same manner as in the first embodiment, and the rectangular portion is connected to an opening 1 (described later) for communicating with the sedimentation tank 2.
At a position above the intermediate body 112 on the side of the upper partition wall 15 and the upper partition wall 114, a size is provided in which a second vertical flow path can be formed as a flow path space for guiding a downward flow of circulation. In addition, the intermediate body 112 for raising the raw water introduced by the upward flow from the raw water introduction pipe 3 and the first vertical flow path for the upward flow over the vertically upper portion thereof, and the downward flow are guided. The above-mentioned second vertical flow path is narrowly limited / partitioned into a flow path for an upward flow and a flow path for a downward flow by a guide wall 116 that partitions the inside of the body of the tank 11. There is a feature that.

The guide wall 116 is formed so as to divide the inside of the upper body in a chord-like manner by a vertical plate over the opposite inner wall, and the lower part thereof is separated from the outer shell wall of the tank. By having the opening 117, it is opened to the intermediate body 112.

A swirl vane device 41 for promoting upward flow is suspended from above the tank 11 in the first vertical flow path for upward flow over the intermediate body portion 112 and the vertically upward portion thereof. The swirling vanes 412 which are installed so as to be held and rotated by a motor 411 promote the ascending flow. Further, a second swirling vane device 42 for facilitating a downward flow is suspended and installed in the second vertical flow path for downward flow in the same configuration as described above, and the swirling vane rotated by a motor 421. 422 promotes the downward flow.

The addition position of the sand of the present embodiment is different from that of the first embodiment in that the sand is added at the upper end of the cone portion 113 of the floc forming tank 11, but other configurations are the same as those of the first embodiment.
Therefore, for convenience of description, necessary components are denoted by the same reference numerals, and the other components are omitted.

The operation obtained by the coagulation / sedimentation apparatus of the present embodiment configured as described above will be described. As in the case of the first embodiment, the bottom of the floc forming tank 11 has a large particle size and a high density. Flocks tend to sediment.

However, according to the apparatus of the present embodiment, the bottom of the tank 11 is formed as a cone portion 113 and is limited to a region having a relatively small horizontal cross-sectional area. Since the raw water is introduced into the tank 11 from 3 in the upward flow, the large flocs deposited or about to be deposited on the same portion are wound up by the upward flow of the raw water. In the tank 11 of this example, in order to further promote the force of winding the flocks, the above-described swirling vane device 41 for promoting the upward flow is provided, and the guide wall 116 is provided so that the flow path of the downward flow is provided. Is clearly defined and the circulating flow is rectified, so that the upward movement of the flock is favorably promoted.

The upward upward flow which winds up the large floc flows over the guide wall 116 on the upper side of the tank, flows into the downward flow path in which the second swirling blade device 42 is provided, and turns to downward downward flow. . Accordingly, the large floc riding on this flow rises from the bottom side of the tank 1 along the swirling blade device 41 and reaches the tank upper side to reach the second swirling blade device 42.
Is shifted to the flow path side of the descending flow in which is provided, and turns to the descending flow. Then, a large proportion of the large floc is transferred from the opening 115 to the sedimentation tank 2 in the overflow manner in the same manner as in the first embodiment by being flown from the opening 115 to the sedimentation tank 2, where the sedimentation is separated. Also,
The remaining large flocks are provided in the lower opening 117 of the guide wall 116.
From the bottom to the bottom side of the tank 11 and is again wound up by the introduction flow of raw water and circulates in the tank.

On the other hand, the very fine flocs and SS in the raw water to which the inorganic coagulant was added before the introduction into the tank 11 and the high-molecular coagulant were entrained on the above-mentioned circulating flow in the middle of this flow. The opportunity for contact to be absorbed by the flock is sufficiently given. Further, the sand supplied to the tank 11 circulates in the same manner, and a sufficient chance of contact with the floc is given.

As described above, according to the apparatus of the present embodiment, the circulating flow in the floc forming tank 11 is promoted by the upward flow of the raw water and the swirling blade devices 41 and 42. In comparison, the provision of the guide wall 116 divides the upward / downward flow path of the circulating flow, so that the promotion effect thereof is more favorably given.

Therefore, the problem that large flocs settle and accumulate in the floc forming tank 1 is reduced and eliminated, and since there is no need to apply extremely strong agitation, the risk of destruction of flocs is reduced. The fine floc containing the fine floc is provided with a sufficient opportunity to come into contact with the larger floc in the middle of the circulation, and the rate at which the fine floc and the like are directly transferred to the sedimentation tank 21 is extremely small. This effectively prevents leakage of fine flocs.

Embodiment 3 In the present embodiment shown in FIG. 3, large flocs having a large density which settle and accumulate at the bottom of the floc forming tank 12 are rolled up by the force of the flow of raw water (water to be treated) introduced into the tank 12. This is the same as Embodiment 2 described above in that a configuration is adopted in which a guide wall for further promoting the circulating flow of the water to be treated in the floc forming tank 12 is employed. The guide wall of the example device is provided as a vertical guide cylinder 126 that partitions and surrounds the periphery of the swirl vane device 4 that promotes the upward flow including the large flocks wound up by the raw water introduction flow, and further enhances the flow circulation flow. The reason is that it can be put on the rectified ascending flow. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted, but the addition position of the polymer flocculant denoted by reference numeral 6 is shown as the wall surface position of the guide cylinder 126 in the drawing. In order to avoid complicating the drawing, the pipe is actually extended to the center position of the guide cylinder 126 and added.

According to this configuration, the flocs having a high density that settle and accumulate on the bottom of the floc forming tank in the first embodiment can be wound by the force of the flow of the raw water (water to be treated) introduced into the tank 12. In addition to the effect, the upward flow and downward flow of the flow circulation flow can be clearly defined by the guide cylinder 126, so that the floc forming tank 12
The problem that large flocs settle and accumulate in the interior is eliminated, and the possibility of breakage of the flocs is also reduced because it is not necessary to apply very strong agitation. Furthermore, the SS in the raw water and the fine flocs containing the same will be given sufficient chances to come in contact with the larger flocs in the middle of circulation.
The rate at which these fine flocks or the like are transferred to the sedimentation tank 21 as they are is extremely small, and leakage of fine floc from the sedimentation tank (leakage) is effectively prevented.

Embodiment 4 The present embodiment shown in FIG. 4 shows an example in which the position and direction of introduction (supply) of reduced water to the floc forming tank 13 are different from those in Embodiment 3 described above. The configuration is the same as that of the third embodiment except that the structure for forming the passage for transferring the water to be treated to the next settling tank 2 is slightly different. Therefore, the parts required for the explanation are denoted by the same reference numerals. The description is omitted. Although FIG. 4 shows the raw water supply pipe 3 simply connected to the wall surface of the guide cylinder 136, the actual supply of raw water in this example is performed by the guide cylinder 136.
Is performed so as to introduce raw water downward (or upward) at a substantially central portion of the above. In addition, the circulation direction of the water to be treated promoted by the swirling blade device 4 is downward in the guide cylinder 136, but may be opposite (upward) together with the swirling blade device 4.

According to the apparatus of the present embodiment, as compared with the apparatus of the third embodiment, the raw water introduction flow is not upward and the flow direction of the to-be-processed water flowing and circulating inside the tank 13 is opposite. However, the fluidity of the circulating flow that settles or accumulates at the bottom of the floc forming tank 13 or winds up the floc to be accumulated depends on the flow path for the ascending flow and the flow path for the descending flow. The partitioning by the guide cylinder 136 and the revolving vane device 4 promotes a circulating and flowing flow turning from the center to the peripheral wall at the bottom of the flock forming tank, and the flock forming tank 1
Since the upward flow is formed along the tank wall of No. 3, a structure for transferring the large flocks to the sedimentation tank 2 in an overflow manner can be provided close to the floc forming tank 13. There is an advantage that the scale can be designed smaller than in the third embodiment.

[0081]

Example 1 and Comparative Example 1 A test apparatus shown in FIG. 8 was constructed by simplifying the apparatus shown in FIG. 3, and a test was conducted under the following conditions. The results are shown in Tables 1 and 2 below. For comparison, a test apparatus shown in FIG. 9 was constructed by simplifying the conventional apparatus shown in FIG. 5, and the same test was conducted. The results are shown in Tables 1 and 2 below. For the purpose of comparison, the same inclined plate as that of Comparative Example 1 was attached to the apparatus shown in FIG. <Equipment specifications> (Example 1) Flock forming tank: square tube type tank, effective capacity 36 liters,
200 mm × 1150 mmH (bottom 60 mm cone, inner cylinder 125 mmφ × 300 mmH) Precipitation tank: square tube type tank, effective capacity 87 liters,
200 mm × 2500 mmH (bottom 60 ° cone, with top inclined plate) (Comparative Example 1) Flock forming tank: square tube type tank, effective capacity 36 liters,
200mm × 1000mmH sedimentation tank: square tube type tank, effective capacity 87 liters,
200mm × 2500mmH (bottom 60 ° cone, with the upper inclined plate) <Test Conditions> Flow: 1.6~2.4m ³ / h precipitation tank LV: of 40 to 60 / h inorganic flocculant: Aluminum Polychlorinated 15ppm polymer flocculant Agent: polyacrylamide-based anionic polymer flocculant 1 ppm Sand input amount: 750 g and 2000 g

[0082]

[Table 1]

[0083]

[Table 2] As can be seen from the results in Table 1, in Comparative Example 1, the sand concentration in the floc-forming tank was lower than that in Example 1, and it was recognized that the sand settled to the lower part of the floc-forming tank. In addition, it was recognized that the amount of sedimentation further increased when the amount of sand input was large, because the floc became heavier.

Further, as can be seen from the results in Table 2, the turbidity of the treated water in the comparative example in which the sedimentation of the sand in the floc forming tank was large was poor, and the tendency was higher than when the sand input amount was 750 g.
In the case of 000 g, it appeared more remarkably.

Further, the amount of sand input 2 in Comparative Example 1 in Table 1 was
Although the sand concentration in the floc forming tank at 000 g is higher than the sand concentration at 750 g of the sand input amount in Example 1, the quality of the treated water is worse in the case of Comparative Example 1, The higher the precipitation tank LV, the greater the tendency for the water quality to deteriorate.

From these facts, it was confirmed that the method and apparatus of the present invention are effective for coagulation and precipitation.

[0087]

According to the present invention, the following effects can be obtained.

According to the first aspect of the present invention, the water to be treated, which is introduced into the tank for the floc forming process, flows upward from the bottom of the tank to generate a circulating flow in the tank. The floc that accumulates on the surface can be wound up by circulating flow, and while maintaining a high flow rate, the suspended solids (SS) contained in the water to be treated and the added sand are absorbed and grown into flocs having a large particle size. Can be. As a result, the amount of fine flocs flowing into the sedimentation separation tank can be reduced. For example, while maintaining a high flow rate of, for example, 50 to 150 m / h, most of the suspension (SS) has a large particle size and the sedimentation velocity is low. As a large floc, the sedimentation and separation can be quickly performed in the sedimentation tank, and the effect of obtaining treated water having excellent water quality can be obtained.

According to the second aspect of the present invention, the floc forming process is capable of generating a recirculating flow including an upward flow from the bottom of the tank and winding up the floc settling to the bottom in the floc forming process. In this case, flocs that adsorb SS and sand can be grown greatly without causing flocculation of the flocs, so that the fine flocs can be formed while passing the water to be treated at a high flow rate of, for example, 50 to 150 m / h. The effect of being able to carry out the treatment in which the outflow from the precipitation separation tank can be suppressed.

According to the third aspect of the present invention, the raw water (water to be treated) is introduced into the floc forming tank in an upward flow,
By simultaneously rectifying the circulating flow of the water to be treated in the tank, the function of promoting the circulating flow, the function of rectifying the circulating flow by the partition wall installed in the tank, and the function of promoting the swirling blade device and the like are achieved. In addition, the flow of the water to be treated in the tank for floc formation treatment is more stable, the large floc having a large sedimentation speed grows well, and the amount of the fine floc transferred to the sedimentation separation tank is reduced. Can be. Therefore, it is effective in improving the quality of the treated water.

According to the fifth aspect of the present invention, the coagulation / sedimentation treatment can be performed at a higher flow rate than before, or a large amount of raw water (water to be treated) can be treated with a small-scale facility.

According to the invention of claim 6, the flow of the water to be treated in the floc forming tank is given by introducing the raw water,
Since the large flocs which are easily deposited on the bottom are wound up with the introduced water, the risk of flocks being deposited on the bottom of the tank can be reduced or eliminated, and the configuration for that can be realized with a relatively simple structure.

According to the seventh aspect of the present invention, since the vertical flow paths of the upward flow and the downward flow are defined by the flow path setting partition, the circulation flowing through each of these flow paths promoted by the flow promotion means. This reduces the risk that the circulating flow is rectified to cause the destruction of the flocs, and the SS, sand or fine flocs are favorably absorbed.

According to the eighth aspect of the present invention, since the direction of the flow of the water to be treated which flows into the sedimentation tank over the overflow plate is guided downward, the tendency of the floc to settle and settle is increased. At the same time, the tendency of the small flocks to flow toward the overflow device can be suppressed.

According to the ninth aspect of the present invention, the partition walls are formed in a meandering manner in the vertical direction, and the upward / overflow / downward (flow into the sedimentation tank) large and smooth flocculation of the floc is promoted. This has the effect of reducing the tendency to shift to the side.

According to the tenth aspect of the present invention, a vertically opposite flow is circulated in and out of the inner cylinder of the substantially double-cylindrical floc forming tank, and this flow is promoted by the flow promoting means such as a swirling blade device. As a result, a rectified flow can be formed as a whole, and it is possible to favorably wind up the flocs and grow the flocs.

According to the eleventh aspect of the present invention, the portion forming the second vertical flow path for the downward flow has a role as an intermediate tank before the transfer of the water to be treated to the settling tank. Meanwhile, the floc that may be deposited on the bottom of the flow path in this portion can return the floc to the first vertical flow path having the effect of winding up the floc in the upward flow, so that the destruction of the floc is suppressed. The flock can be satisfactorily wound up.

According to the twelfth aspect of the present invention, the circulating flow flowing from the downward flow to the upward flow can flow smoothly at the bottom of the floc forming tank, and the flocks are wound up while the breakage of the flocks is suppressed. Can be performed favorably.

According to the thirteenth aspect of the present invention, since the horizontal cross-sectional area is small at the bottom of the floc forming tank in which the flocks are wound, the flow velocity can be increased to increase the hoisting force, and therefore, the flocks can be more effectively prevented from being deposited. The effect that can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a schematic configuration of an apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a schematic configuration of an apparatus according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a schematic configuration of an apparatus according to an embodiment of the present invention.

FIG. 5 is a view showing an example of a conventional coagulation / sedimentation apparatus.

FIG. 6 is a diagram schematically illustrating a problem in a case where flocs are transferred from a floc forming tank to a sedimentation tank by an overflow method.

FIG. 7 is another diagram schematically illustrating a problem when the floc is transferred from the floc forming tank to the settling tank by an overflow method.

FIG. 8 is a diagram illustrating a processing test (example) according to the present invention;
The figure which showed the coagulation sedimentation apparatus which simplified the apparatus of Embodiment 3 shown in FIG.

9 is a diagram showing an agglomerated sedimentation apparatus which is a simplified version of the conventional apparatus of FIG. 5 for performing a comparative example in comparison with a processing test using the apparatus of FIG.

[Explanation of symbols]

 1, 11, 12, 13 ... floc forming tank 101, 111, 121, 131 ... trunk 112 ... intermediate trunk 102, 113, 122, 132 ... cone 103, 114, 123 ··· Upper partition 104, 115, 124 ... opening 116 ... flow path setting partition 117 ... opening 2 ... sedimentation tank 201 ... overflow wall 202 ... trunk 203 ... cone Part 204 ・ ・ ・ Overflow gutter 205 ・ ・ ・ Flow guide wall 3 ・ ・ ・ Raw water (water to be treated) introduction pipe 4,41,42 ・ ・ ・ Swirl vane device 401,411,421 ・ ・ ・ Motor 402,403 ··· Rotating blades 404 ··· Rotating shaft 5 ··· Inorganic filler supply pipe 6 ··· Polymer coagulant supply pipe 7 ··· Sand addition device 701 ··· Pump 702 ··· Cyclone 703・ Sludge discharge pipe

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/56 C02F 1/56 Z F term (Reference) 4D015 BA03 BA05 BA24 BB09 BB12 CA05 CA06 CA08 CA09 CA14 DA04 DA16 DB02 DC06 DC08 EA02 EA07 EA32 EA36 FA16 4D062 BA03 BA05 BA24 CA05 CA06 CA08 CA09 CA14 DA04 DA16 DB02 DC06 DC08 EA02 EA07 EA32 EA36 FA16

Claims (13)

[Claims] Claims 1. A floc containing insoluble fine particles is circulated and fluidized in a tank containing a suspension (SS) and added with a chemical treating agent necessary for floc formation and insoluble fine particles having a large specific gravity. A floc formation treatment for growing, and a sedimentation treatment for sedimenting and separating flocs grown so as to have a large sedimentation velocity containing insoluble fine particles by the treatment, are separated from a floc sedimentation separation tank from the floc formation treatment tank. A coagulation and sedimentation method for sequentially performing each of the above-described processes so that the water to be processed continuously flows over the overflowing plate, wherein the flow of the water to be processed in a tank for performing the floc forming process Means that the to-be-processed water flows in an upward flow from the bottom of the floc forming tank so that the flocs settled at the bottom are wound up and flow by the upward flow. Coagulating sedimentation method of the suspension, characterized. 2. A floc containing insoluble particulates is circulated and fluidized in a tank containing a suspension (SS) and added with a chemical treating agent necessary for floc formation and insoluble particulates having a large specific gravity. A floc formation treatment for growing, and a sedimentation treatment for sedimentation of the floc, which contains the insoluble fine particles by the treatment and have a high sedimentation velocity, from water, and separates a floc sedimentation separation tank from the floc formation treatment tank. A coagulation and sedimentation method for sequentially performing each of the above-mentioned treatments so that the water to be treated continuously overflows the upper part of the overflow plate, wherein a flow path defined by a partition in a tank for the floc formation treatment Characterized in that the circulating fluid flow is turned around and flows upwards of the water to be treated, so as to wind up flocs settling at the bottom of the tank. Collecting precipitation method. 3. A method for coagulating and sedimenting a suspension, comprising a method according to claim 1 and 2. 4. The method according to claim 1, wherein
An inorganic coagulant, one of the chemical treating agents, is added in advance to the water to be treated introduced into the floc forming tank, and the other chemical treating agents, a polymer coagulant and insoluble fine particles, are directly added to the tank. A method of coagulating and sedimenting a suspension. 5. The method according to claim 1, wherein
A method for coagulating and sedimenting a suspension, wherein an upward flow velocity of a fluidized circulating flow provided to a bottom portion of a tank for floc formation is 50 m / h or more. 6. A floc containing insoluble fine particles is circulated and fluidized in a tank containing a suspension (SS) and added with a chemical treating agent necessary for floc formation and insoluble fine particles having a large specific gravity. A floc forming tank to be grown,
A floc sedimentation tank which contains insoluble fine particles and has grown so as to have a high sedimentation velocity by the above-mentioned treatment, is sedimented to the bottom of the tank, and the separated water is discharged from the upper part of the tank. An agglomerated sedimentation apparatus comprising: an overflow flow path configured to flow the treated water over an upper portion of an overflow plate provided to partition both tanks, wherein the floc forming tank includes: An apparatus for coagulating and settling a suspended substance, wherein a treated water introduction pipe for flowing treated water in an upward flow is connected to the bottom of the tank. 7. A floc containing insoluble fine particles is circulated and fluidized in a tank containing a suspension (SS) and added with a chemical treating agent necessary for floc formation and insoluble fine particles having a large specific gravity. A floc forming tank to be grown,
A floc sedimentation tank that sediments floc that has grown at a high sedimentation velocity including the insoluble fine particles by the above treatment and sediments at the bottom of the tank and discharges separated water from the upper part of the tank. An agglutination / sedimentation apparatus having an overflow flow path configured to flow the treated water over an upper portion of an overflow plate provided to partition both tanks, wherein the floc forming tank has Providing a flow path setting partition extending in a substantially vertical direction that defines a vertical flow path for an upward flow and a vertical flow path for a downward flow in the tank; A flow promoting means for circulating and flowing the water to be treated from the direction flow path to the other longitudinal flow path, and a treatment water circulation flow turning part for turning a downward to upward flow of the lower part of the partition wall close to the bottom of the tank; A suspension characterized by being provided Coagulation sedimentation equipment. 8. The overflow channel according to claim 6, wherein the overflow channel has an overflow plate and a guide wall provided in the sedimentation tank to guide the overflow water downward into the sedimentation tank. A coagulation and sedimentation apparatus for a suspension. 9. The overflow channel according to claim 6 or 7, wherein the overflow channel is formed by an overflow plate and overflow water distribution guide walls provided respectively in a floc forming tank and a settling tank on both sides of the overflow plate. The overflowing water distribution guide wall on the side of the floc forming tank is formed as a meandering and intricate flow path, and the overflowing water distribution guide wall is suspended from the water surface into the water, and the processing target facing the floc forming tank at the middle position in the vertical direction of the floc forming tank. An apparatus for coagulating and settling a suspension, the apparatus being provided to form a water inflow opening. 10. The flow path setting partition wall provided in the floc forming tank according to claim 6 or 7, wherein the flow path setting partition wall is a vertically open cylindrical wall installed in the floc forming tank, and the circulation wall is formed inside the cylindrical wall. An apparatus for coagulating and settling a suspension, comprising a flow promoting means for promoting flow. 11. The flock forming tank according to claim 6, wherein the first vertical flow path for a vertically long upward flow set by the flow path setting partition and the first vertical direction. A second vertical channel chamber for a vertically short downward flow biased toward the upper side of the flow channel and defined by the flow channel setting partition wall. It is connected to the settling tank through a flow type flow path, and the lower part of the second vertical flow path is connected to the first vertical flow path so that flocs can be returned and circulated. Apparatus for coagulating and settling the suspension. 12. The configuration according to claim 6, and claims 7 to 1.
An apparatus for coagulating and sedimenting a suspension, comprising: 13. The floc forming tank according to claim 6, wherein a shape near the tank bottom is provided in a cone shape in which a horizontal cross-sectional area decreases from the top to the bottom. Apparatus for coagulating and settling the suspension.