JP2000117005A5 - - Google Patents

Description

【００８３】
【表２】

この表１の結果から分かるように、比較例１では実施例１よりもフロック形成槽中の砂濃度が低く、これは砂がフロック形成槽の下部に沈降したことによることが認められた。また、砂の投入量が多い場合はフロックがより重くなることから、沈降量が更に増加することが認められた。
【００８４】
また表２の結果から分かるように、フロック形成槽での砂の沈降が多い比較例の場合の処理水の濁度は悪く、その傾向は砂投入量が７５０ｇのときより２０００ｇのときの方が顕著に現れた。
【００８５】
更に、表１の比較例１における砂投入量２０００ｇのときのフロック形成槽中の砂濃度は、実施例１における砂投入量７５０ｇのときの同砂濃度よりも高いにもかかわらず、処理水の水質は比較例１の場合の方が悪く、沈澱槽ＬＶを高くするほど水質が悪くなる傾向が大きくなった。
【００８６】
これらのことから、本発明の方法、装置が凝集沈澱処理に有効であることが確認された。
【００８７】
【発明の効果】
本願の各請求項の発明によれば、以下の効果が奏される。
【００８８】
請求項１の発明によれば、フロック形成処理の槽に導入する被処理水を槽底部から上向流で流入させて循環流動をこの槽内に生じさせるので、フロック形成槽の底部に沈積するフロックを循環流動で巻き上げることができ、高い流速を維持しながら、被処理水中に含まれる懸濁物（ＳＳ）と添加した砂とを吸合し粒径の大きなフロックに成長させることができる。これによって、沈澱分離の槽に流入する微フロックの量を少なくできて、例えば５０〜１５０ｍ／ｈという高流速を保持しながら、大部分の懸濁物（ＳＳ）を粒径が大きく沈降速度が大きいフロックとして沈澱槽で迅速に沈降分離することができ、水質の優れた処理水を得ることができるという効果が奏される。
【００８９】
請求項２の発明によれば、フロック形成処理の槽内に、槽底部から上向流を含む循還回流を生じさせて底部に沈降するフロックを巻き上げることができるので、フロック形成処理の際にフロックの沈積を招くことがなく、ＳＳ及び砂を吸合したフロックを大きく成長できるので、例えば５０〜１５０ｍ／ｈという高流速での被処理水の通水を行いながら、微フロックの沈澱分離の槽からの流出を抑制した処理を行うことができるという効果が奏される。
【００９０】
請求項３の発明によれば、原水（被処理水）のフロック形成槽への導入を上向流で行うことと、該槽内での被処理水の循環流動を整流化することを同時に行うことによって、循環流動流の促進作用と、槽内に設置した隔壁による循環流動の整流と旋回羽根装置等による促進作用が相俟って、フロック形成処理の槽内における被処理水の流動がより一層安定し、沈降速度が大きい大フロックが良好に成長し、微フロックが沈澱分離の槽に移行する量を低減することができる。従って、処理水の水質向上に効果がある。
【００９１】
請求項５の発明によれば、従来に比べて高流速での凝集沈澱処理が行え、あるいは小規模の設備で大量の原水（被処理水）処理をすることができる。
【００９２】
請求項６の発明によれば、フロック形成槽内における被処理水の流れを原水の導入によって与え、底部に沈積し易い大フロックをこの導入水で巻き上げるので該槽の底部にフロックが沈積する虞を軽減ないし解消でき、しかもそのための構成が比較的簡易な構造で実現できる。
【００９３】
請求項７の発明によれば、上向流と下向流の縦方向流路が流路設定隔壁により区画されるので、流動促進手段により促進されるこれらの各流路を流れる循還流動流が整流されてフロックの破壊を招く虞を軽減させ、ＳＳ，砂あるいは微フロックの吸合が良好に行われる。
【００９４】
請求項８の発明によれば、越流板を越えて沈澱槽に移行・流入する被処理水の流れの方向を下向きに案内するので、フロックの沈降・沈澱する傾向を高めると共に、同時に小フロックが溢流装置側に流れる傾向を抑制することができる。
【００９５】
請求項９の発明によれば、隔壁が上下蛇行状に入り組み、上向き−越流−下向き（沈澱槽内に流入）という大フロックの円滑・迅速な沈降促進と、微フロックの水面側への移行傾向の低減化という効果が奏される。
【００９６】
請求項１０の発明によれば、略二重円筒型のフロック形成槽の内筒内外に上下反対向きの流れを循環させ、この流れを旋回羽根装置等の流動促進手段で促進することで全体として整流化した流れを形成でき、フロックの巻き上げとフロックの成長を良好に得ることができる。
【００９７】
請求項１１の発明によれば、下向流のための第二の縦方向流路を形成する部分が、沈澱槽への被処理水の移行の前段で中間槽的な役割を示しながら、この部分の流路の底部に沈積する虞のあるフロックは上向流でフロックを巻き上げる作用を有する第一の縦方向流路にフロックを戻すことができるので、フロックの破壊を抑制しながら、該フロックの巻き上げを良好に行うことができる。
【００９８】
請求項１２の発明によれば、下向流から上向流に転向する循環流動流をフロック形成槽の底部において円滑に流すことができて、フロックの破壊を抑制しながらフロックの巻き上げを良好に行うことができる。
【００９９】
請求項１３の発明によれば、フロックを巻き上げるフロック形成槽の底部において水平断面積が小さいので流速を高めて巻き上げ力を大きくすることができ、したがってフロックの沈積をより効果的に防ぐことができるという作用が得られる。
【図面の簡単な説明】
【図１】本発明の実施形態１の装置の構成概要を示した図。
【図２】本発明の実施形態２の装置の構成概要を示した図。
【図３】本発明の実施形態３の装置の構成概要を示した図。
【図４】
本発明の実施形態４の装置の構成概要を示した図。
【図５】
従来の凝集沈澱装置の一例を示した図。
【図６】
フロック形成槽から沈澱槽にフロックを越流式で移行させる場合の問題を図解的に示した図。
【図７】
フロック形成槽から沈澱槽にフロックを越流式で移行させる場合の問題を図解的に示したもう一つの図。
【図８】
本発明の処理試験（実施例）を行うために図３に示した実施形態３の装置を簡略化した凝集沈澱装置を示した図。
【図９】
図８の装置を用いた処理試験と対比する比較例を行うために図５の従来装置を簡略化した凝集沈澱装置を示した図。
【符号の説明】
１，１１，１２，１３・・・フロック形成槽
１０１，１１１，１２１，１３１・・・胴部
１１２・・・中間胴部
１０２，１１３，１２２，１３２・・・コーン部
１０３，１１４，１２３・・・上部隔壁
１０４，１１５，１２４・・・開口
１１６・・・流路設定隔壁( 案内壁）
１１７・・・開口
２・・・沈澱槽
２０１・・・越流壁
２０２・・・胴部
２０３・・・コーン部
２０４・・・溢流樋
２０５・・・越流水流通ガイド壁
３・・・原水（被処理水）導入管
４，４１，４２・・・旋回羽根装置
４０１，４１１，４２１・・・モータ
４０２，４０３・・・旋回羽根
４０４・・・回転軸
５・・・無機凝集剤供給管
６・・・高分子凝集剤供給管
７・・・砂供給装置
７０１・・・ポンプ
７０２・・・サイクロン
７０３・・・汚泥排出管Title: Method and apparatus for coagulation and sedimentation
[Claims]
A floc containing insoluble fine particles is circulated and flown in a tank containing a suspension (SS) and a chemical treating agent necessary for floc formation and to which insoluble fine particles having a large specific gravity are added. A floc formation treatment for growing, and a sedimentation treatment for sedimentation and separation of the floc grown so as to have a large sedimentation velocity containing insoluble fine particles by the treatment, from the water for the floc formation treatment. Coagulation sedimentation method in which the respective treatments are sequentially performed in such a manner that the water to be treated continuously moves on the overflow plate to overflow,
The flow of the water to be treated in the tank for performing the floc formation treatment is such that the water to be treated flows in an upward flow from the bottom of the floc formation tank, and the flocs settled at the bottom are wound up by the upward flow and flow. A method for coagulating and sedimenting a suspension.
2. 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 floc containing water-insoluble fine particles by the treatment and having a high sedimentation velocity from water, and separating a floc sedimentation separation tank from the floc formation treatment tank. A method of coagulation and sedimentation in which each of the above-described treatments is sequentially performed so that the water to be treated continuously overflows the upper part of the overflow plate,
The circulating flow is diverted to the upward flow of the water to be treated along the flow path defined by the partition walls in the tank of the floc forming treatment, and the floc settling at the bottom of the tank is wound up. A method of coagulating and sedimenting a suspension.
3. A method for coagulating and sedimenting a suspension, comprising a method according to claim 1 and 2.
4. The chemical treating agent according to claim 1, wherein an inorganic coagulant, which is one of the chemical treating agents, is added in advance to the water to be introduced into the floc forming tank. A coagulating precipitation method of a suspension, wherein the polymer coagulant and insoluble fine particles are added directly to the tank.
5. The flocculation of suspended matter according to claim 1, wherein the upward flow velocity of the fluid circulation flow supplied to the bottom of the floc forming tank is 50 m / h or more. Precipitation method.
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 for growing, a floc sedimentation tank for sedimenting floc containing insoluble fine particles by the treatment and having a large sedimentation velocity and having a high sedimentation rate at the bottom of the tank and discharging separated water from the upper part of the tank; A flocculating sedimentation device comprising an overflow type flow path for allowing the transfer of the water to be treated to the floc sedimentation tank from above the overflow plate provided to divide the two tanks,
A flocculation and sedimentation apparatus for suspended matter, 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.
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 for growing, a floc sedimentation tank for sedimenting floc containing insoluble fine particles by the treatment and having a large sedimentation velocity and having a high sedimentation rate at the bottom of the tank and discharging separated water from the upper part of the tank; A flocculating sedimentation device comprising an overflow type flow path for allowing the transfer of the water to be treated to the floc sedimentation tank from above the overflow plate provided to divide the two tanks,
In the floc forming tank, a flow path setting partition extending in a substantially vertical direction is provided to define a vertical flow path for upward flow and a vertical flow path for downward flow in the tank. A flow promoting means for circulating and flowing the water to be treated from one of the longitudinal flow paths to the other longitudinal flow path, and a treatment water circulating flow turning part for turning a downward to upward flow of the lower part of the partition wall Is provided in the vicinity of the bottom of the tank.
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 channel, and the overflowed water distribution guide wall is suspended from the surface of the water into the water, and the processing target facing the floc forming tank at the vertical middle position of the floc forming tank. An apparatus for coagulating and settling a suspension, the apparatus being provided so as 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 the vertically long upward flow set by the flow path setting partition is provided with the first vertical flow path. A second vertical flow chamber for a vertically short downward flow deflected toward the upper side of the flow path and defined by the flow path setting partition, and A flow path is connected to the settling tank, and a lower portion 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. An apparatus for coagulating and sedimenting a suspension, having both the structure of claim 6 and the structure of any of claims 7 to 11.
13. A floc forming tank according to any one of claims 6 to 12, wherein the shape near the tank bottom is provided in the shape of a cone whose horizontal cross-sectional area decreases from the top to the bottom. Apparatus for coagulating and settling the suspension.
DETAILED DESCRIPTION OF THE INVENTION
[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method and an apparatus for coagulating and precipitating a suspension (SS) in water to be treated. More specifically, the present invention relates to a method of adding a high-density particle such as sand and a chemical treating agent to water to be treated to obtain a suspension. The present invention relates to a method and an apparatus for efficiently removing SS, which precipitates as aggregates having a high sedimentation velocity.
[0002]
[Prior art]
As a coagulation sedimentation method for removing fine suspended solids (SS) in the water to be treated, a method and apparatus for rapidly sedimentation / sedimentation separation by flocculation of SS and floc growth are disclosed in, for example, French Patent No. 1411172. French Patent No. 1501912 (filed on September 28, 1969), French Patent No. 2071027 (filed on December 16, 1969), Japanese Patent No. 2634230, Japanese Patent Application Laid-Open No. 8-47606, and the like. I have.
[0003]
In this method, fine suspended particles, which cannot be separated at high speed by natural sedimentation in a stock solution, are combined with insoluble and high-density particles such as sand (hereinafter collectively referred to as “sand”) and a chemical treating agent. Utilizing the method, it grows into aggregates (flocks) containing SS, and separates them from the water to be treated into high-density agglomerates (flocks) that easily sediment the sand.
[0004]
According to this method, the floc at the time of sedimentation and separation by a general coagulation and sedimentation method is as low as about 1.01 to 1.02 and the sedimentation speed is low, so that the treatment at a high flow rate is impossible. A large sedimentation velocity is obtained because of the inclusion of sand with a density of about 2.7 in the floc, and flocs can be settled and separated quickly while flowing the water to be treated at a high flow rate. It is considered that there is an advantage that the processing flow rate per contact can be increased, and that the apparatus can be downsized if the amount of treated water is the same.
[0005]
The principle configuration of an apparatus for implementing this method is, for example, a flocculation tank in which an inorganic flocculant and a polymer flocculant are added to raw water and agitated, and flocs formed into small particles by flocculation in the flocculation tank grow into large flocs. A floc forming tank to be settled and a floc having a large sedimentation rate including sand grown in the floc forming tank settle and settle at the bottom of the tank, and the treated water overflows from the upper part of the tank as supernatant water and is separated therefrom. It is configured as a one-pass circulation type processing tank facility provided in order. The raw water flowing into the treatment tankWater) Is given a stirring state and a flow rate suitable for the treatment in each of the tanks for flocculation, floc formation and precipitation (see FIG. 5).
[0006]
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.
[0007]
One of the problems is that not only the above-mentioned method but also the case where SS is to be coagulated and sedimented by the coagulation sedimentation method is used, but flocs are generated as having a uniform size and uniform density. Difficulty, rather, is that the addition of sand produces a large sedimentation velocity, which inevitably tends to broaden the floc sedimentation velocity distribution.
[0008]
That is, the growth of floc is caused by various factors such as fluctuations in the quality of the water to be treated, types and amounts of various chemical treatment agents to be added, dispersion of sand and the like, presence of SS, and local changes in flow velocity. Because of the influence of various fluctuation factors, it is inevitable that the distribution of the sedimentation velocity of each floc generated and grown widens. In other words, even if a floc is generated under the same conditions when viewed macroscopically, a large number of generated flocs have a diameter of about 1 to 4 mm when viewed microscopically. Some of them are large and have a large amount of sand involved, and the sedimentation velocity reaches 15 to 1000 m / h. On the other hand, 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.
[0009]
Therefore, as a measure for preventing 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 the treated water is kept as it is. Proposes to capture the overflowing fine flocs contained in the water with a separator.
[0010]
[Problems to be solved by the invention]
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 there is a disadvantage in terms of installation equipment that a separation plate is required. . In addition to this, the burden of maintenance and inspection of the separation plate, which is inevitable for clogging, is large, running costs are increased, 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 that requires continuous operation.
[0011]
By the way, as shown in the example of FIG. 5, the transition from the floc formation tank to the sedimentation tank is performed by the upper part of the overflow plate, as shown in the example of FIG. It is good to go beyond. This is because, when 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 to the sedimentation tank quickly, 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 becomes longer. According to the method of moving over the top of the overflow plate, the floc concentration is maintained high in the floc forming tank, the contact opportunity to absorb fine floc generated by the aggregation of the inorganic flocculant is increased, and the sedimentation speed is reduced. A large floc can be grown, the reaction time required for floc formation can be shortened, and the floc forming tank can be miniaturized.
[0012]
However, in the method in which the floc is transferred to the settling tank over the top of the overflow plate, the floc having a large particle size and heavy, especially the sand not absorbed by the floc, settles at the bottom of the floc forming tank. There is a difficulty. This problem has the consequence, as shown in FIGS. 6 and 7, of the fact that flocs of large particle size gradually accumulate at the bottom of the floc forming tank, and in other cases, this type of equipment usually has a sedimentation tank. Separate the sand from the sludge collected in the above, and recycle it so as to add it to the flocculation tank again.However, the amount of sand to be reused becomes insufficient, and flocs of the desired density are not formed. This problem is described as a problem that flocs having a low density are formed, and flocs leak into treated water in a sedimentation tank, resulting in deterioration of treated water. 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 equipment for adding sand 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 flocs may occur, resulting in a failure in stable operation.
[0013]
In addition, in order to eliminate the problem of heavy flocs accumulating in the floc forming tank in the overflow method, strong stirring may be performed in the floc forming tank. As a result, the particle size of the floc is reduced and the sedimentation velocity is reduced, leading to a problem that the upward flow in the sedimentation tank cannot be set to a high flow velocity. From these facts, it is necessary to satisfy the trade-off demands 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 the floc forming tank and the sedimentation tank, and the floc forming tank prevents sedimentation of sand and high density floc by relatively strong stirring, and grows floc by weak stirring in the intermediate tank. Although it is conceivable to shift the process to a sedimentation 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.
[0014]
The inventor of the present invention has accomplished the present invention based on the facts that have been found during intensive studies in order to solve the various problems of the prior art described above.
[0015]
That is, the present invention relates to a technique based on combining SS and sand to grow a high-density floc in order to remove suspended solids (SS) in raw water, and in general, the technique is not necessarily uniform (size). It is an object of the present invention to reduce as much as possible the problem that flocs averaged to the sedimentation velocity due to density or the like are not generated.
[0016]
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 as simple and small equipment as possible, thereby widespread use of the above technology as equipment on an industrial scale. It is an object of the present invention to provide a method and an apparatus for removing coagulated sediment of SS in raw water, which are made possible.
[0017]
[Means for Solving the Problems]
The above object is achieved by the invention of each claim described in the claims of the present application.
[0018]
That is, according to the inventor's 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 the floc forming tank, and the above-mentioned overflow In the formula, the water to be treated is transferred from the floc forming tank to the settling tank.AndI came to find something important. In other words, the former configuration allows the flow of the heavy large flocks to be prevented from settling and accumulating at the bottom of the floc forming tank, thereby increasing the chance of absorbing the fine flocs to the large flowing flocs. Therefore, it is effective to reduce the fine floc that migrates to the sedimentation tank, and by adopting the latter overflow type transfer method together, only the large floc quickly migrates to the sedimentation tank and the 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.
[0019]
According to the invention of the method for coagulating and precipitating a suspension according to claim 1, water to be treated containing a suspension (SS) and to which a chemical treating agent necessary for floc formation and insoluble fine particles having a large specific gravity are added is circulated in a tank. A floc forming process for growing flocs containing insoluble fine particles while flowing, and a sedimentation process for separating flocs grown to have a large sedimentation speed containing the insoluble fine particles by the above process by sedimentation from water. A flocculation / sedimentation method in which the water to be treated continuously flows over an overflow plate that separates a floc sedimentation separation tank from a flocculate sedimentation tank, wherein each of the above-described processes is sequentially performed. The flow of the water to be treated in the tank for performing the treatment is such that the water to be treated flows in the upward flow from the bottom of the floc forming tank, and the flocs settling at the bottom are wound up by the upward flow. Characterized in that so as to flow.
[0020]
In the above configuration, sand (specific gravity of about 2.7) is generally used as the “insoluble fine particles” having a large specific gravity, and is not limited, but generally has a particle size of about 10 to 200 μm, preferably 50 to 200 μm. Are preferred. In the following description, the insoluble fine particles are represented by sand.
[0021]
The sedimentation velocity v of particles such as sand in a fluid is expressed by the following Stokes' equation.
v = g (ρs−ρ) d^Two / Μ / 18
(Where ρs: density of particles, ρ: density of water, d: particle diameter, μ: viscosity coefficient of water, g: gravitational acceleration)
If the specific gravity and particle size are too large, the proportion of the sand settling in the tank for floc formation processing without adsorbing to the floc increases, so that the sand having the above particle size range is suitable. .
[0022]
The "chemical treatment agent" required for floc formation generally includes an inorganic coagulant such as polyaluminum chloride (PAC), ferric chloride, and ferric sulfate; an anionic polymer coagulant; A polymer flocculant such as a polymer flocculant is used in combination. Inorganic flocculants are used to flocculate suspended solids (SS) and sand in the water to be treated, and polymeric flocculants are used to grow these flocs into large flocs.
[0023]
The method of adding the sand and the flocculant is performed by adding the sand and the flocculant to the tank for the floc formation treatment. However, the inorganic flocculant can also 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.
[0024]
The suspended state in which flocculation and floc growth of the suspended matter are performed in the floc formation treatment tank is provided by, for example, generating a circulating flow with a swirling blade device or a stirrer to such an extent that sand having a large specific gravity does not settle.
[0025]
The floc sedimentation and separation tank that sediments the floc containing sand and separates it from water is configured to transfer the water to be treated by a flow from the floc formation treatment tank over the top 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 packed 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 are circulated and flow along the flow of the circulating fluid of the water to be treated in the floc forming tank, so that sedimentation separation 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 in which a fine floc is retained in a portion to perform a filtering action such as growth and sedimentation and aggregation of the fine floc. Such a filler-filled layer can be formed, for example, by randomly collecting plastic short tube-type small pieces having a diameter of about 4 to 12 mm and a length of about 15 to 20 mm. However, the present invention is not particularly limited to this, and a filler in which a large number of holes are formed in the spherical surface of a hollow sphere inside, a teralet packing, or the like can also be used. In addition, since the filler-filled layer needs to function as a water passage for passing an upward flow at a high flow rate, it forms a stagnation portion with respect to 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.
[0026]
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. As described, sand can be separated from the extracted sludge using a separator such as a cyclone and reused.
[0027]
The most significant feature of the present invention is that water to be treated introduced into a tank for floc formation treatment is caused to flow upward from the bottom of the tank to generate a circulating flow in the tank. As a result, the floc settling at the bottom is wound up by circulation flow, and while maintaining a high flow rate, the suspended solids (SS) contained in the water to be treated are 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.
[0028]
According to the present invention, most of the suspended solids (SS) in the water to be treated have a large particle size and a high sedimentation velocity while the water to be treated is passed at a high flow rate of, for example, 50 to 150 m / h. It becomes floc and can be quickly settled in the sedimentation tank.
[0029]
According to a second aspect of the present invention, there is provided a method for flocculating and settling a suspension, wherein the water to be treated is directed upward from the bottom of the tank in order to generate a circulating flow that winds up the floc settling at the bottom of the tank for floc formation. Instead of flowing in the flow, 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 bottom of the tank is The circulating flow is turned from the counterflow to the upward flow, and the floc settling at the bottom of the tank is wound up.
[0030]
In the above configuration, the circulating flow flowing in one direction in the passage formed by the partition can be generated by using, for example, one or a plurality of swirling blade devices.
[0031]
ADVANTAGE OF THE INVENTION According to this invention, in the tank of floc formation processing, the recycle circulating flow containing the upward flow which rises inward or outward from the tank bottom can be generated, and the floc which settles to the bottom can be rolled up. Since flocs can be largely grown by absorbing SS and sand without causing sedimentation and accumulation of flocs in the treatment tank, the flow of the water to be treated at a high flow rate of, for example, 50 to 150 m / h , A process can be performed in which the outflow of the fine floc from the precipitation and separation tank is suppressed.
[0032]
The invention of claim 3 is characterized by having both of the above methods, and according to the present invention, the action of promoting the circulating flow by introducing the water to be treated in the upward flow from the bottom of the tank, and Combined with the rectification of the circulating flow by the installed partition walls and the promoting action by the swirling blade device, etc., the circulating flow in the tank for the floc forming process is further stabilized, and the floc having a large particle size and a large sedimentation speed grows well. However, it is possible to reduce the amount of the fine floc transferred to the precipitation separation tank.
[0033]
According to a fifth aspect of the present invention, in each of the above inventions, the upward flow velocity of the fluid circulation flow provided to the bottom of the tank for the floc forming treatment is 50 m / h or more, preferably 200 m / h or more. .
[0034]
ADVANTAGE OF THE INVENTION According to this invention, the coagulation and sedimentation process can be performed at a higher flow rate than before, and a large amount of raw water (water to be treated) can be treated with a small-scale facility.
[0035]
The invention of the apparatus for coagulating and precipitating a suspension according to claim 6 circulates water to be treated containing a suspension (SS) and containing a chemical treating agent necessary for floc formation and insoluble fine particles having a large specific gravity in a tank. A floc forming tank for growing flocs containing insoluble fine particles while flowing, and a floc containing the insoluble fine particles grown by the above-mentioned treatment to have a large sedimentation velocity is settled at the bottom of the tank and separated water is discharged from the upper part of the tank. A floc sedimentation tank, and an overflow flow path configured to flow the transfer of the water to be treated from the floc forming tank to the floc sedimentation tank over an overflow plate provided to partition both tanks. Wherein the treated water introducing pipe through which the treated water flows in an upward flow is connected to the bottom of the floc forming tank.
[0036]
In the above configuration, the flock forming tank may be of various types such as a cylindrical cross section having a horizontal cross section, a rectangular section, and a combination of curves and straight lines (for example, a combination of a semicircle and a rectangle). The structure can be determined from the flow rate of the water to be treated in the floc formation tank, the flow rate of the overflow water determined by the cross-sectional area of the overflow type flow path, and the like.
[0037]
The method of discharging from the upper part of the sedimentation tank is not limited, but it is often preferable to use an overflow type using a gutter having an overflow weir because of its simple structure.
[0038]
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 deposited on the bottom are rolled up with the introduced water. Is greatly reduced or eliminated.
[0039]
The invention of the apparatus for coagulating and precipitating a suspension according to claim 7 circulates 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 in a tank. A floc forming tank for growing flocs containing insoluble fine particles while flowing, and a floc that grows to have a large sedimentation speed containing the insoluble fine particles by the above treatment is settled at the bottom of the tank and the separated water is discharged from the upper part of the tank. A floc sedimentation tank, and an overflow flow path configured to flow the transfer of the water to be treated from the floc forming tank to the floc sedimentation tank over an overflow plate provided to divide the two tanks. Wherein the floc forming tank has a substantially vertical direction defining a vertical flow path for upward flow and a vertical flow path for downward flow in the tank. Provide an extended flow path setting partition In addition, 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 water to be treated is circulated to divert a downward to upward flow of the lower part of the partition. The part is provided near the bottom of the tank.
[0040]
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 only this vertical plate. It may be provided in combination with an inclined plate or the like so as to be suitable for circulation.
[0041]
The flow promoting means can be configured using a swirling blade device, a stirrer, or the like.
[0042]
According to the present invention, the vertical flow paths of the upward flow and the downward flow are separated by the flow path setting partition walls, so that the circulating flow flowing through each of these flow paths promoted by the flow promotion means is rectified. Thus, there is an effect that the possibility of causing the destruction of the flocs is reduced, and the SS, sand or fine flocs are absorbed well.
[0043]
The invention according to claim 8 is the apparatus in which the flow path setting partition is provided, wherein the overflow type flow path is provided with an overflow plate and a guide provided in the sedimentation tank to guide overflow water downward into the sedimentation tank. It has a wall.
[0044]
According to 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 flocs to settle and settle is increased, and at the same time, the small flocs overflow. The effect of suppressing the tendency to flow toward the device can be obtained.
[0045]
According to a ninth aspect of the present invention, in the apparatus provided with the flow path setting partition, the overflow plate and the overflow water distribution guide walls provided in the floc forming tank and the sedimentation tank on both sides of the overflow plate, meander vertically. The flow-through guide wall on the floc formation tank side is suspended in water from above the water surface, and the water to be treated facing the floc formation tank at a vertical middle position of the floc formation tank. It is characterized by being provided so as to form an inflow opening.
[0046]
The above configuration is typically configured such that an overflow plate located at a certain depth or less from the water surface is provided between partition walls (overflow water distribution guide walls) that partition both tanks suspended from the water surface into the water. In this manner, the partition walls are in a meandering (labyrinth-like) manner, and the large flocks in the upward-overflow-downward direction (flow into the sedimentation tank) are smoothly and rapidly settled. The effect of promoting and reducing the tendency of the fine flocs to move to the water surface side can be obtained.
[0047]
According to a tenth aspect of the present invention, in the apparatus provided with the flow path setting partition, the flow path setting partition provided in the floc forming tank is a vertically open tubular wall installed in the floc forming tank. A flow promoting means for promoting the circulating flow is provided inside the cylindrical wall.
[0048]
According to the present invention, inside the substantially double-cylindrical floc forming tank, the flow inside the inner cylinder and the flow in the opposite direction between the flow path between the inner cylinder and the outer cylinder are circulated. The flow can be promoted by a flow promoting means such as a swirling blade device, so that a flow that is rectified as a whole can be formed, and it is possible to favorably wind up flocks and grow flocs.
[0049]
An invention according to claim 11 is the apparatus in which the flow path setting partition is provided, wherein the flock forming tank is a first vertical flow path for a vertically long upward flow set by the flow path setting partition. A second vertical flow path for a downward short flow deflected toward the upper side of the first vertical flow path and defined by a flow path setting partition, and The lower part of the second vertical flow path is communicated with the first vertical flow path so that the floc can be returned and circulated, while being connected to the sedimentation tank via the overflow flow path from the vertical flow path. It is characterized by having.
[0050]
According to the present invention, the portion forming the second vertical flow path for the downward flow shows the role of an intermediate tank before the transfer of the water to be treated to the settling tank, Flock that may be deposited at the bottom of the road can return the flock to the first vertical flow path having the function of winding up the flock in the upward flow, so that the flock can be wound up while suppressing the destruction of the flock. Can be performed well.
[0051]
According to a twelfth aspect of the present invention, there is provided a structure in which a treated water introduction pipe for allowing treated water to flow in an upward flow from the bottom of the floc forming tank is connected to the floc forming tank. And a flow path setting partition wall for flowing through the air passage.
[0052]
ADVANTAGE OF THE INVENTION According to this invention, the circulating fluid flow which turns from a downward flow to an upward flow can flow smoothly at the bottom part of a floc formation tank, and performs the winding of the floc satisfactorily while suppressing the destruction of the floc. be able to.
[0053]
A thirteenth aspect of the present invention is characterized in that, in each of the above-described device inventions, the flock 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.
[0054]
According to the present invention, since the horizontal cross-sectional area is small at the bottom of the floc forming tank in which the flocs are wound up, the flow velocity can be increased and the hoisting force can be increased, and thus the effect that the flocs can be more effectively prevented from being deposited. can get.
[0055]
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]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1
The present example shown in FIG. 1 is an example in which a floc having a high density settled and deposited on the bottom of a floc forming tank 1 is rolled up by the force of the flow of raw water (water to be treated) introduced into the tank 1. The device is shown.
[0057]
In FIG. 1, reference numeral 1 denotes a flock forming tank, and a tank wall structure forming an outer shell of the tank body has a body portion 101 having a vertical cylindrical shape on an upper side and a lower side having a horizontal cross-sectional diameter gradually decreasing toward a bottom. It has a cone section 102 and an opening 104 provided below an upper partition wall 103 in which a part of the body section 101 is formed as an overflow water distribution guide wall. From the opening 104, the partition wall 103 and a part of the next settling tank 2 are formed. It is provided so that the water to be treated is transferred to the sedimentation tank 2 in an overflow manner between the overflow walls 201 formed as side walls. The upper body 101 is formed by combining a semicylindrical portion on the left side of the figure and a rectangular part on the right side of the figure when viewed in a horizontal plane, and the rectangular part is provided with the sedimentation tank described above. Opening 104 for communicationMouth 1It is provided so as to have the above-mentioned upper partition wall 103 forming the liquid crystal element 04.
[0058]
A raw water introduction pipe 3 is connected to the bottom of the cone portion 102 of the floc forming layer 1 so that raw water is introduced upward into the tank 1. At the center position, a swirling blade device 4 for promoting circulation flow is installed so as to be suspended from above the tank 1, and is turned upward at the center position of the tank 1 by swirling blades 402 and 403 rotated by a motor 401. In the vicinity of the inner wall of the tank, the downward circulation flow is promoted. 404IsThis is a rotating shaft on which the swirling blades 402 and 403 are assembled.
[0059]
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. Reference numeral 6 denotes a polymer flocculant supply pipe which is configured to add a polymer flocculant into the floc forming tank 1 from the side of the cone 102 of the tank 1. 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 forming 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.
[0060]
Through the floc forming tank 1 having the above-described configuration, the floc containing the SS in the raw water together with the sand flows over the overflow wall 201 and is introduced into the sedimentation tank 2 as described above. 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 with a horizontal cross-sectional diameter gradually decreasing toward the bottom. An overflow device having a cone portion 203 and an overflow gutter 204 for allowing the treated water to overflow around the upper portion of the tank;ToThe floc is quickly settled and settled at the bottom of the cone 203, and the supernatant water (treated water) is discharged to the outside from the overflow gutter 204. In addition, 205 is an overflow water flow that guides the flow direction of the water to be treated that has flowed into and settled in the sedimentation tank 2 over the overflow wall 201.ThroughA guide wall which acts to increase the tendency of the flocs of relatively low density to settle and settle, and at the same time to suppress the tendency of the flocs to flow to the overflow device side.
[0061]
The operation obtained by the coagulation and sedimentation apparatus of the present embodiment configured as described above will be described. Generally, large flocs having a large particle diameter and a high density are settled and deposited at the bottom of the floc forming tank 1. In the apparatus of the example, 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. Is introduced in an upward flow, so that large flocs that have accumulated or are about to accumulate in this area 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.
[0062]
The upward rising force that winds up the large floc formed along the center line of the tank 1 gradually decreases as it reaches the cylindrical body 101 having a large horizontal cross-sectional area on the upper side, and the peripheral wall in the tank 1 is reduced. Turning to a downward descent while diffusing to the 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. The circulation is promoted by the inflow position (bottom portion) and direction (upward) of the raw water and the swirling blade device 4 described above.
[0063]
On the other hand, the extremely fine flocs and SS in the raw water to which the inorganic coagulant was added before being introduced into the tank 1 and the high-molecular coagulant get on the circulating flow. The opportunity for contact to be absorbed by the existing flock is sufficiently provided. Further, the sand supplied from above the water surface of the tank 1 also has a sufficient contact opportunity to be sucked into the circulating flocs.
[0064]
In addition, through the opening 104 to the overflow channel provided at a predetermined position and height of the body 101 of the floc forming tank 1, the water to be treated is constantly and continuously transferred to the sedimentation tank 2 side. Because of the flow, a large proportion of the large flocs move to the sedimentation tank 2 along the flow of this transition.
[0065]
Therefore, according to the present example device, by specifying the inflow position and direction of the raw water and the swirl blade device 4, the circulation flow in the floc forming tank 1 is promoted. The problem of sedimentation / deposition is eliminated, and the possibility of destruction of flocs is reduced or eliminated because it is not necessary to apply very strong agitation. In addition, SS in the raw water and fine flocs containing the same are given a sufficient opportunity to come into contact with larger flocs in the middle of the circulating flow. Is extremely small, and the prevention of leakage (leak) 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 in reducing the burden of maintenance and inspection to cope with this. is there.
[0066]
Embodiment 2
The example shown in FIG.ofAs in the first embodiment, the large flocs having a high density settled and deposited on the bottom of the floc forming tank 11 are rolled up by the force of the flow of raw water (water to be treated) introduced into the tank 11. In addition to the above, there is shown an example of 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.
[0067]
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. And an upper body 111 that continues upward from the middle body. The upper body 111 has a configuration in which 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 communicates with the settling tank 2. It is provided with a size that can form a second vertical flow path as a flow path space for guiding a downward flow of circulation at a position above the intermediate body 112 on the side of the opening 115 and the upper partition 114 described below. I have. 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.
[0068]
The guide wall 116 is formed so as to partition the inside of the upper body in a chord shape by a vertical plate across the opposing inner wall, and the lower part thereof has an opening 117 separated from the tank outer shell wall. By having it, it is opened to the intermediate body 112.
[0069]
And onIn writingA swirl vane device 41 for promoting upflow is installed in the first vertical flow path for upward ascending flow across the middle body portion 112 and the vertically upper portion thereof so as to be suspended from above the tank 11. The upward flow is promoted by the swirling vanes 412 rotated by the motor 411. In the second vertical flow path for the downward flow, a second swirling vane device 42 for facilitating the downward flow is suspended and installed in the same configuration as described above, and the swirl vane rotated by the motor 421. 422 promotes the downward flow.
[0070]
In addition, although the addition position of the sand of this example 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, the other configuration is the same as that of the first embodiment. For the sake of convenience of description, necessary components are denoted by the same reference numerals, and the other components are omitted.
[0071]
The operation obtained by the coagulation / sedimentation apparatus of the present embodiment configured as described above will be described. As in the first embodiment, large flocs having a large particle diameter and a high density are settled at the bottom of the floc forming tank 11. Tends to deposit.
[0072]
However, according to the apparatus of the present example, the bottom of the tank 11 is formed as a cone 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 in an upward flow, the large flocs deposited or about to be deposited on the same portion are rolled up in the upward flow of the raw water. In the tank 11 of the present example, in order to further promote the force of winding up 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 formed. Is clearly defined and the circulating flow is rectified, so that the upward movement of the flock is favorably promoted.
[0073]
The upward flow that winds up the large floc flows over the guide wall 116 on the upper side of the tank, flows into the flow path of the downward flow in which the second swirling blade device 42 is provided, and turns to downward downward flow. Therefore, 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 and moves to the flow path side of the descending flow where the second swirling blade device 42 is provided. And turn to 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, and is settled and separated therefrom. The remaining large flocks descend from the opening 117 at the lower part of the guide wall 116 to the bottom side of the tank 11, are again taken up by the introduction flow of raw water, and circulate in the tank.
[0074]
On the other hand, the very fine flocs and SS in the raw water to which the inorganic flocculant was added before being introduced into the tank 11 and further the high-molecular flocculant flow on the circulating flow to another floc in the middle of this flow. Ample opportunity for contact to be absorbed is provided. Further, the sand supplied to the tank 11 also circulates in the same manner, and a sufficient chance of contact with the floc is given.
[0075]
As described above, according to the present example device, the circulation flow in the floc forming tank 11 is promoted by the introduction of the raw water in the upward flow and the swirling blade devices 41 and 42, and further compared with the first embodiment. The provision of the guide wall 116 divides the upward and downward flow paths of the circulating flow, so that the effect of promoting the flow is more favorably provided.
[0076]
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 flocs, which contain fine flocs, are provided with a chance to come into contact with the larger flocs in the middle of circulation, and these fine flocs, etc.To twoThe transfer ratio is extremely small, and the prevention of the leakage (leak) of the fine floc from the sedimentation tank is effectively achieved.
[0077]
Embodiment 3
The present example shown in FIG. 3 shows an example in which large flocs having a large density that 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. The second embodiment is the same as the second embodiment in that a guide wall for further promoting the circulating flow of the water to be treated in the floc forming tank 12 is employed. A vertical guide cylinder 126 that partitions and surrounds the swirl vane device 4 that promotes the upward flow including the large flocs that have been wound up by the raw water introduction flow, so that the upward flow that further rectifies the flow circulation flow is provided. Can be put onI'llIt is in the sea. 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.
[0078]
According to this configuration, in addition to the effect that the floc having a high density settled and deposited on the bottom of the floc forming tank in the first embodiment can be rolled up by the force of the raw water (water to be treated) introduced into the tank 12. Since the upward and downward flow paths of the circulating flow can be clearly defined by the guide cylinder 126, the problem that large flocs settle and accumulate in the floc forming tank 12 is eliminated and is extremely strong. Since there is no need to provide agitation, the risk of destruction of flocs is also reduced. Further, the SS in the raw water and the fine flocs containing the same are provided with a sufficient opportunity to come into contact with the larger flocs in the course of circulation, and these fine flocs and the like are directly settled in the settling tank.To twoThe transfer ratio is extremely small, and the prevention of the leakage (leak) of the fine floc from the sedimentation tank is effectively achieved.
[0079]
Embodiment 4
The present example shown in FIG. 4 is different from the third embodiment in that the floc forming tank 13 is used.RuharaThis is an example in which the position of water introduction (supply) and the direction of introduction are different, and other structures are different except that the structure for forming the passage for transferring the water to be treated to the next settling tank 2 is slightly different. Since the third embodiment is the same as the third embodiment, the parts required for the description are denoted by the same reference numerals, and the description is omitted. In FIG. 4, the raw water supply pipe 3 is shown simply as being connected to the wall surface of the guide cylinder 136, but the actual supply of raw water in this example is downward (or approximately) at the approximate center of the guide cylinder 136. This is done so that raw water is introduced upward. In addition, although the circulation direction of the water to be treated promoted by the swirling blade device 4 is downward in the guide cylinder 136, it may be opposite (upward) together with the swirling blade device 4.
[0080]
The apparatus of this example is different from the apparatus of Embodiment 3 in that the raw water introduction flow is not upward and that the direction of the flow of the treated 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. And the swirling vane device 4 promotes a circulating flow that is turned from the center to the peripheral wall at the bottom of the flock forming tank, and further along the tank wall of the flock forming tank 13. Since an upward flow is formed, a structure for transferring the large floc to the sedimentation tank 2 in an overflow manner can be provided in the vicinity of the floc formation tank 13, so that the overall scale of the present example apparatus is compared with that of the third embodiment. Small There is an advantage that can be designed.
[0081]
【Example】
Example 1, Comparative Example 1
The test apparatus of FIG. 8 was constructed by simplifying the apparatus of FIG. 3, and a test was performed under the following conditions, and the results are shown in Tables 1 and 2 below. For comparison, the 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 sake of comparison, the apparatus shown in FIG.BoardWas attached.
<Equipment specifications>
(Example 1)
Flock forming tank: square tube type tank, effective capacity 36 liters, 200mm x 1150mmH (bottom 60mm cone, inner cylinder 125mmφ x 300mmH)
Sedimentation tank: Square tube type tank, effective capacity 87 liters, 200mm × 2500mmH (bottom 60 ° cone, top inclinedBoardWith)
(Comparative Example 1)
Flock forming tank: square tube type tank, effective capacity 36 liters, 200 mm × 1000 mmH
Sedimentation tank: Square tube type tank, effective capacity 87 liters, 200mm × 2500mmH (bottom 60 ° cone, top inclinedBoardWith)
<Test conditions>
Flow rate: 1.6-2.4m^Three / H
Precipitation tank LV: 40-60 m / h
Inorganic flocculant: Polyaluminum chloride 15ppm
Polymer flocculant: Polyacrylamide anionic polymer flocculant 1ppm
Sand input: 750g and 2000g
[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 in the lower part of the floc-forming tank. Further, it was recognized that the sedimentation amount further increased when the amount of sand input was large, because the floc became heavier.
[0084]
Further, as can be seen from the results in Table 2, the turbidity of the treated water in the case of the comparative example in which the sedimentation of the sand in the floc formation tank was large was poor, and the tendency was higher when the sand input amount was 2000 g than when the sand input amount was 750 g. Appeared remarkably.
[0085]
Furthermore, although the sand concentration in the floc forming tank when the sand input amount was 2000 g in Comparative Example 1 in Table 1 was higher than the sand concentration in Example 1 when the sand input amount was 750 g, the treated water was higher. The water quality was worse in the case of Comparative Example 1, and the higher the precipitation tank LV, the greater the tendency for the water quality to deteriorate.
[0086]
From these, it was confirmed that the method and apparatus of the present invention are effective for the coagulation and precipitation treatment.
[0087]
【The invention's effect】
According to the invention of each claim of the present application, the following effects are exerted.
[0088]
According to the first aspect of the present invention, the water to be introduced into the tank for the floc formation treatment is caused to flow in an upward flow from the bottom of the tank and a circulating flow is generated in the tank, so that the water is deposited on the bottom of the floc formation tank. The floc can be wound up by circulation flow, and while maintaining a high flow rate, the suspended matter (SS) contained in the water to be treated and the added sand can be absorbed and grown into flocs having a large particle size. 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, 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.
[0089]
According to the second aspect of the present invention, in the floc forming process, the floc that settles at the bottom by generating a recirculating flow including an upward flow from the bottom of the bath can be rolled up. Since floc that adsorbed SS and sand can be grown large without causing floc sedimentation, fine floc can be sedimented and separated while passing water to be treated at a high flow rate of, for example, 50 to 150 m / h. The effect that the process which suppressed outflow from the tank can be performed is produced.
[0090]
According to the invention of claim 3, the introduction of the raw water (water to be treated) into the floc forming tank is performed in the upward flow, and the circulating flow of the water to be treated in the tank is rectified simultaneously. By this, the promoting action of the circulating flow, the rectification of the circulating flow by the partition wall installed in the tank, and the promoting action of the swirling blade device, etc., combine to improve the flow of the water to be treated in the tank of the floc forming process. Large flocs, which are more stable and have a high sedimentation velocity, grow well, and the amount of fine flocs transferred to the sedimentation separation tank can be reduced. Therefore, it is effective in improving the quality of the treated water.
[0091]
According to the fifth aspect of the present invention, the coagulation and 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.
[0092]
According to the invention of claim 6, the flow of the water to be treated in the floc forming tank is given by the introduction of the raw water, and the large flocs which are easily deposited on the bottom are rolled up by the introduced water, so that the flocs may be deposited on the bottom of the tank. Can be reduced or eliminated, and the configuration therefor can be realized with a relatively simple structure.
[0093]
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 walls, the circulating circulating flow flowing through each of these flow paths promoted by the flow promoting means. Is reduced to reduce the risk of flock breakage, and SS, sand, or fine floc is absorbed well.
[0094]
According to the invention of claim 8, since the direction of the flow of the water to be treated which flows into the sedimentation tank beyond 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. Can be suppressed from flowing to the overflow device side.
[0095]
According to the ninth aspect of the present invention, the partition walls are in a meandering manner in a vertical manner, and the upward / overflow / downward (inflow into the sedimentation tank) large and smooth flocculation of the floc is promoted, and the fine floc is promoted toward the water surface side. This has the effect of reducing the transition tendency.
[0096]
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 type floc forming tank, and this flow is promoted by a flow promoting means such as a swirling blade device as a whole. It is possible to form a rectified flow, and it is possible to obtain good flocking and flocking growth.
[0097]
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. The floc that may be deposited on the bottom of the flow path of the portion can return the floc to the first vertical flow path having the function of winding up the floc in the upward flow, so that the floc can be prevented from being broken while suppressing the destruction of the floc. Can be satisfactorily wound up.
[0098]
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 can be satisfactorily wound up while suppressing the breakage of the flocs. It can be carried out.
[0099]
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 for winding the flocks, the flow velocity can be increased and the hoisting force can be increased, and thus the sedimentation of the flocs can be more effectively prevented. Is 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
Embodiment of the present invention4The figure which showed the structure outline of the apparatus of FIG.
FIG. 5
The figure which showed an example of the conventional coagulation sedimentation apparatus.
FIG. 6
The figure which showed the problem at the time of transferring a floc from a floc formation tank to a sedimentation tank by an overflow method schematically.
FIG. 7
FIG. 4 is another diagram schematically illustrating a problem when the floc is transferred from the floc forming tank to the sedimentation tank by an overflow method.
FIG. 8
The figure which showed the coagulation sedimentation apparatus which simplified the apparatus of Embodiment 3 shown in FIG. 3 in order to perform the processing test (Example) of this invention.
FIG. 9
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. 8.
[Explanation of symbols]
1, 11, 12, 13, ... floc forming tank
101, 111, 121, 131 ... trunk
112 ・ ・ ・ Intermediate trunk
102, 113, 122, 132 ... cone part
103, 114, 123 ... upper partition
104, 115, 124 ... opening
116 ・ ・ ・ Channel setting partition( Guide wall)
117 ... opening
2 ... settling tank
201 ・ ・ ・ overflow wall
202 ... trunk
203 ・ ・ ・ cone part
204 ・ ・ ・ Overflow gutter
205 ...Overflow water distributionGuide wall
3 Raw water (treated water) introduction pipe
4,41,42 ... Swing blade device
401, 411, 421 ... motor
402, 403 ... swirl vane
404 ・ ・ ・ Rotary axis
5 ・ ・ ・ InorganicAggregationAgent supply pipe
6 ... supply pipe for polymer flocculant
7 ... SandSupplyapparatus
701 ... pump
702: cyclone
703 ・ ・ ・ Sludge discharge pipe