JP7220602B2 - Aeration stirring system, its installation method and oxidation ditch device - Google Patents

Aeration stirring system, its installation method and oxidation ditch device Download PDF

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JP7220602B2
JP7220602B2 JP2019053153A JP2019053153A JP7220602B2 JP 7220602 B2 JP7220602 B2 JP 7220602B2 JP 2019053153 A JP2019053153 A JP 2019053153A JP 2019053153 A JP2019053153 A JP 2019053153A JP 7220602 B2 JP7220602 B2 JP 7220602B2
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impeller
partition wall
straightening plate
circulating water
central partition
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JP2020151673A (en
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泰彦 嶌田
学 荒井
龍真 吉田
啓太郎 森下
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Organo Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/10—Biological treatment of water, waste water, or sewage

Description

本発明は、曝気撹拌システムおよびその設置方法とオキシデーションディッチ装置に関する。 TECHNICAL FIELD The present invention relates to an aeration agitation system, its installation method, and an oxidation ditch device.

下水や汚水等の有機廃水である被処理水を、微生物を用いて生物学的に処理するために、無端の循環水路を有する反応タンクを含むオキシデーションディッチ装置（酸化溝装置）を用いる方法が知られている。反応タンクには、一般に縦軸型や横軸型などのエアレータを含む曝気撹拌システムが設けられている。エアレータのインペラが回転することにより、被処理水を十分に曝気する。特許文献１～６には、長円形状や馬蹄形状などの循環水路に、曝気性能や維持管理性に優れている縦軸型エアレータを含む曝気撹拌システムが設けられたオキシデーションディッチ装置が開示されている。 In order to biologically treat water to be treated, which is organic wastewater such as sewage and sewage, using microorganisms, there is a method using an oxidation ditch device (oxidation ditch device) including a reaction tank having an endless circulating water channel. Are known. The reaction tank is generally provided with an aeration agitation system including an aerator, such as a vertical shaft type or a horizontal shaft type. The water to be treated is sufficiently aerated by rotating the impeller of the aerator. Patent Documents 1 to 6 disclose an oxidation ditch apparatus provided with an aeration agitation system including a vertical shaft type aerator having excellent aeration performance and maintainability in an oval-shaped or horseshoe-shaped circulating water channel. ing.

特許第５８３９４３９号公報Japanese Patent No. 5839439 特許第６３６７７５２号公報Japanese Patent No. 6367752 特許第５７６６５３４号公報Japanese Patent No. 5766534 特許第５５９１７５１号公報Japanese Patent No. 5591751 特開昭６１－１４９２９３号公報JP-A-61-149293 特公平４－７２７６号公報Japanese Patent Publication No. 4-7276

反応タンク内に縦軸型エアレータを配置した場合、インペラの回転によって、縦軸型エアレータから見て一方の側には、循環水路内の水流と一致する方向の推進力が生じるのに対し、他方の側には逆向きの推進力が生じる。それにより、縦軸型エアレータの付近で水流の乱れが生じ、かつ流速が低下する。その結果、被処理水に対して高効率で良好な生物学的処理を行うことが困難である。 When the vertical axis aerator is arranged in the reaction tank, the rotation of the impeller produces a driving force on one side of the vertical axis aerator in the direction of the water flow in the circulation channel, whereas the other side. On the side of , a reverse propulsive force is generated. As a result, turbulence occurs in the water flow near the vertical axis aerator, and the flow velocity decreases. As a result, it is difficult to perform highly efficient and favorable biological treatment of the water to be treated.

そこで、本発明の目的は、被処理水に対して高効率で良好な処理を行うことを可能にする曝気撹拌システムおよびその設置方法とオキシデーションディッチ装置を提供することにある。 SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an aeration stirring system, a method for installing the system, and an oxidation ditch device that enable highly efficient and favorable treatment of water to be treated.

本発明の、周囲壁と周囲壁の内側に位置する中央区画壁とによって少なくとも一部に直線部分を含む被処理水の循環水路を構成する反応タンクの内部に配置される曝気撹拌システムが、循環水路の直線部分に配置された、垂直軸を中心として回転可能なインペラと、インペラを、一部を除いて囲むように配置された整流板とを有し、整流板は、反応タンクを流れる循環水流の前記直線部分における前記インペラの上流側に向かって凸状の整流板湾曲部と、整流板湾曲部の両端から循環水流の前記直線部分における前記インペラの下流側に直線的に延びる１対の整流板直線部とを有し、インペラは、前記上流側において整流板湾曲部に覆われ、前記下流側においては１対の整流板直線部の間で開放されており、インペラの回転中心が、循環水路の幅方向において、中央区画壁の主面から、循環水路の全幅の１／３～２／３の距離だけ離れた位置に配置されている。 According to the present invention, the aeration and agitation system arranged inside the reaction tank, which constitutes a circulating channel of the water to be treated which includes at least a part of a straight portion by the peripheral wall and the central partition wall located inside the peripheral wall, performs circulation. It has an impeller arranged in a straight portion of the water channel and rotatable about a vertical axis , and a rectifying plate arranged so as to surround the impeller except for a part, and the rectifying plate is used to circulate through the reaction tank. A pair of straightening vane curved portions projecting toward the upstream side of the impeller in the straight portion of the water flow, and a pair of straightening plate curved portions extending linearly from both ends of the straightening vane curved portion toward the downstream side of the impeller in the straight portion of the circulating water flow. The impeller is covered with the straightening plate curved portion on the upstream side, and is open between the pair of straightening plate straight portions on the downstream side, and the rotation center of the impeller is In the width direction of the circulation channel, it is arranged at a position separated from the main surface of the central partition wall by a distance of 1/3 to 2/3 of the total width of the circulation channel.

本発明によると、被処理水に対して高効率で良好な処理を行うことができる。 ADVANTAGE OF THE INVENTION According to this invention, highly efficient and favorable treatment can be performed with respect to to-be-processed water.

本発明の一実施形態のオキシデーションディッチ装置を模式的に示す平面図である。1 is a plan view schematically showing an oxidation ditch device according to one embodiment of the present invention; FIG. 図１に示すオキシデーションディッチ装置の変形例の一部を模式的に示す拡大平面図である。FIG. 3 is an enlarged plan view schematically showing a part of a modification of the oxidation ditch apparatus shown in FIG. 1; 図１のオキシデーションディッチ装置の曝気撹拌システムを模式的に示す側面図である。FIG. 2 is a side view schematically showing the aeration stirring system of the oxidation ditch apparatus of FIG. 1; 図１の要部の拡大図である。2 is an enlarged view of a main part of FIG. 1; FIG. 図１に示すオキシデーションディッチ装置の他の変形例の要部の拡大平面図である。FIG. 11 is an enlarged plan view of a main part of another modification of the oxidation ditch apparatus shown in FIG. 1; 第２の実施例のオキシデーションディッチ装置を模式的に示す平面図である。FIG. 4 is a plan view schematically showing an oxidation ditch apparatus of a second embodiment; 第３の実施例のオキシデーションディッチ装置を模式的に示す平面図である。FIG. 11 is a plan view schematically showing an oxidation ditch apparatus of a third embodiment; 第５の実施例のオキシデーションディッチ装置を模式的に示す平面図である。FIG. 11 is a plan view schematically showing an oxidation ditch device of a fifth embodiment; 第６の実施例のオキシデーションディッチ装置を模式的に示す平面図である。FIG. 11 is a plan view schematically showing an oxidation ditch device of a sixth embodiment; 第４の比較例のオキシデーションディッチ装置を模式的に示す平面図である。FIG. 11 is a plan view schematically showing an oxidation ditch device of a fourth comparative example; 図８の要部の拡大図である。FIG. 9 is an enlarged view of the main part of FIG. 8; 第８の実施例のオキシデーションディッチ装置を模式的に示す平面図である。FIG. 11 is a plan view schematically showing an oxidation ditch apparatus of an eighth embodiment; 本発明の他の実施形態のオキシデーションディッチ装置を模式的に示す平面図である。FIG. 4 is a plan view schematically showing an oxidation ditch device according to another embodiment of the present invention;

以下、本発明の実施の形態について図面を参照して説明する。
図１に、本発明の一実施形態のオキシデーションディッチ装置（酸化溝装置）を示している。このオキシデーションディッチ装置は、反応タンク１を有している。この反応タンク１は、長円形状の周囲壁２と、周囲壁２に囲まれた空間の内部に位置し、長円形状の幅方向の中心を通り長手方向に沿って延びる中央区画壁３とを有する。中央区画壁３の両端はいずれも周囲壁２の内面に当接せず間隔を置いて位置している。さらに、中央区画壁３の端部と周囲壁２の内面との間の間隔を通って、中央区画壁３の両側へ延びる湾曲区画壁４が設けられている。図１に示す例では、湾曲区画壁４は、周囲壁２の両端の湾曲部分２ａと実質的に平行であって、周囲壁２の湾曲部分２ａと直線部分２ｂとの移行部分付近まで延びている。それにより、周囲壁２と中央区画壁３とに仕切られた無端の循環水路が構成されている。この循環水路の一部は、湾曲区画壁４によって２系統に分割されつつ周囲壁２の湾曲部分２ａおよび湾曲区画壁４に沿って流れるように案内される。なお、本発明のオキシデーションディッチ装置は、湾曲区画壁４と周囲壁２の両端の湾曲部分２ａとが互いに平行である構成には限定されない。図２に示す変形例のように、湾曲区画壁４と周囲壁２の湾曲部分２ａとが、半径の大きさが互いに異なり、かつ中心位置が互いにずれて偏心した半円弧状であってもよい。その場合、循環水流の上流側において湾曲区画壁４が周囲壁２に近接し、下流側において湾曲区画壁４が周囲壁２から離れて位置するように偏心していることが好ましい。図２には、このような変形例の反応タンク１の一部のみを示しているが、図示されている部分の反対側（図２の下方）においても同様に、循環水流の上流側において湾曲区画壁４が周囲壁２に近接し、下流側において湾曲区画壁４が周囲壁２から離れて位置するように、湾曲区画壁４と湾曲部分２ａとが偏心している。それにより循環水路内の流れの流速を高めることができる。 BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an oxidation ditch device (oxidation ditch device) according to one embodiment of the present invention. This oxidation ditch apparatus has a reaction tank 1 . The reaction tank 1 has an elliptical peripheral wall 2, and a central partition wall 3 located inside the space surrounded by the peripheral wall 2 and extending along the longitudinal direction through the center of the elliptical shape in the width direction. have Both ends of the central partition wall 3 are not in contact with the inner surface of the peripheral wall 2 and are spaced apart from each other. Furthermore, curved partition walls 4 are provided that extend to both sides of the central partition wall 3 through the spacing between the ends of the central partition wall 3 and the inner surface of the peripheral wall 2 . In the example shown in FIG. 1, the curved partition wall 4 is substantially parallel to the curved portions 2a at both ends of the peripheral wall 2 and extends to the vicinity of the transition between the curved portion 2a and the straight portion 2b of the peripheral wall 2. there is Thereby, an endless circulating water channel partitioned by the peripheral wall 2 and the central partition wall 3 is formed. A portion of this circulating water channel is divided into two systems by the curved partition wall 4 and guided to flow along the curved portion 2 a of the peripheral wall 2 and the curved partition wall 4 . The oxidation ditch apparatus of the present invention is not limited to the configuration in which the curved partition wall 4 and the curved portions 2a at both ends of the peripheral wall 2 are parallel to each other. As in the modification shown in FIG. 2, the curved partition wall 4 and the curved portion 2a of the peripheral wall 2 may have different radii and have semi-arcuate eccentric center positions. . In that case, it is preferable to be eccentric so that the curved partition wall 4 is close to the peripheral wall 2 on the upstream side of the circulating water flow and the curved partition wall 4 is positioned away from the peripheral wall 2 on the downstream side. Although FIG. 2 shows only a part of the reaction tank 1 of such a modified example, the opposite side of the part shown (lower side of FIG. 2) is similarly curved on the upstream side of the circulating water flow. The curved partition wall 4 and the curved portion 2a are eccentric so that the partition wall 4 is close to the peripheral wall 2 and the curved partition wall 4 is located away from the peripheral wall 2 on the downstream side. Thereby, the velocity of the flow in the circulation channel can be increased.

循環水路の直線部分は、周囲壁２の直線部分２ｂによって形成されており、実質的に周囲壁２の直線部分２ｂと同じ部分であると言える。循環水路の直線部分に、曝気撹拌システムを構成する縦軸型エアレータ１１が配置されている。図３に示すように、縦軸型エアレータ１１は、回転可能な羽根部であって回転軸５を有するインペラ６と、インペラ６の回転軸５に連結された電動機７および減速機８と、整流板９とを有する。インペラ６の上端が循環水路内の被処理水の液面１０（２点鎖線で図示）の近傍に位置している。本実施形態では、図３，４に示すインペラ６の回転中心６ａが、長円形状の循環水路の直線部分において、中央区画壁３の主面から距離Ｗ２だけ離れた位置に配置されている。ここで言う主面とは、中央区画壁３の、周囲壁２に対向する面であって、局所的な凹凸部が存在する場合にはその局所的な凹凸部を除いた平坦面である。この距離Ｗ２は、反応タンク１（循環水路）の直線部分の全幅Ｗ１の１／３～２／３である。整流板９は一端が開放された略Ｕ字状の仕切り壁であり、水流の上流側に向かって凸状の半円状または半楕円状または半長円状の整流板湾曲部９ａと、この整流板湾曲部９ａの両端から下流側に直線的に延びる１対の整流板直線部９ｂとを有している。インペラ６は１対の整流板直線部９ｂと整流板湾曲部９ａとに囲まれた空間に位置し、上流側において整流板湾曲部９ａに覆われ、下流側においては１対の整流板直線部９ｂの間で開放されている。 The straight portion of the circulation channel is formed by the straight portion 2b of the peripheral wall 2 and can be said to be substantially the same portion as the straight portion 2b of the peripheral wall 2 . A vertical shaft type aerator 11 that constitutes an aeration stirring system is arranged in the straight portion of the circulating water channel. As shown in FIG. 3, the vertical shaft type aerator 11 includes an impeller 6 which is a rotatable blade portion and has a rotating shaft 5, an electric motor 7 and a reduction gear 8 connected to the rotating shaft 5 of the impeller 6, a rectifying a plate 9; The upper end of the impeller 6 is located near the surface 10 of the water to be treated in the circulating water channel (illustrated by a two-dot chain line). In this embodiment, the rotation center 6a of the impeller 6 shown in FIGS. 3 and 4 is arranged at a position separated from the main surface of the central partition wall 3 by a distance W2 in the linear portion of the oval circulating water passage. The main surface referred to here is the surface of the central partition wall 3 facing the peripheral wall 2, and is a flat surface excluding the local irregularities, if any. This distance W2 is 1/3 to 2/3 of the total width W1 of the straight portion of the reaction tank 1 (circulating water channel). The rectifying plate 9 is a substantially U-shaped partition wall with one end open. It has a pair of rectifying plate straight portions 9b extending linearly downstream from both ends of the rectifying plate curved portion 9a. The impeller 6 is located in a space surrounded by a pair of rectifying plate straight portions 9b and a rectifying plate curved portion 9a. 9b are open.

本実施形態のオキシデーションディッチ装置では、循環水路内に被処理水が供給され、縦軸型エアレータ１１の電動機７および減速機８が作動してインペラ６を時計方向に回転させる。インペラ６の回転により、インペラ６の外側（周囲壁２側）には、時計方向に流れる水流の上流側から下流側に向かう推進力が生じる。インペラ６の内側（中央区画壁３側）には、水流に逆行して下流側から上流側に向かう推進力が生じるが、この推進力を受けた水流の少なくとも一部は略Ｕ字状の整流板９に遮られ、下流側から上流側に向かうように方向転換される。なお、インペラ６が時計方向に回転する構成のみならず、反時計方向に回転する場合もあり得るが、いずれの場合も、循環水流と同じ方向にインペラ６が回転する。 In the oxidation ditch apparatus of this embodiment, the water to be treated is supplied into the circulating water channel, and the electric motor 7 and the speed reducer 8 of the vertical axis aerator 11 are operated to rotate the impeller 6 clockwise. Due to the rotation of the impeller 6, a driving force is generated on the outside of the impeller 6 (on the side of the surrounding wall 2) from the upstream side to the downstream side of the water flow flowing in the clockwise direction. Inside the impeller 6 (on the side of the central partition wall 3), a propulsive force is generated that runs counter to the water flow and moves from the downstream side to the upstream side. It is blocked by the plate 9 and the direction is changed from the downstream side to the upstream side. The impeller 6 may rotate counterclockwise as well as clockwise. In either case, the impeller 6 rotates in the same direction as the circulating water flow.

このような構成のオキシデーションディッチ装置では、循環水路内の水流に対する、インペラ６の回転により生じる推進力が流速の低下を引き起こすことを防ぐことが望まれる。そこで、本実施形態では、インペラ６の回転が循環水流の流速の低下を招かないようにするために、循環水路の幅方向におけるインペラ６の位置を調整した構成を提案する。すなわち、循環水路の幅方向において、中央区画壁３の主面から距離Ｗ２だけ離れた位置にインペラ６の回転中心６ａを配置し、その距離Ｗ２は循環水路の全幅Ｗ１の１／３～２／３である（図４参照）。このような位置にインペラ６を配置し、略Ｕ字状の整流板９が、整流板湾曲部９ａの両端から連続し、循環水路の水流の上流側から下流側に向かって延びる１対の整流板直線部９ｂを有することで、水流の流速の低下を抑えることができる。好ましくは、整流板直線部９ｂの、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さ、厳密に言うとインペラ６の回転中心６ａから整流板直線部９ｂの先端までの、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さが、インペラ６の最大外径Ｄの１～３倍である。 In the oxidation ditch apparatus having such a configuration, it is desirable to prevent the impeller 6 from causing a decrease in the flow velocity of the water flow in the circulation channel due to the driving force generated by the rotation of the impeller 6 . Therefore, the present embodiment proposes a configuration in which the position of the impeller 6 in the width direction of the circulating water passage is adjusted so that the rotation of the impeller 6 does not cause a decrease in the flow velocity of the circulating water flow. That is, the center of rotation 6a of the impeller 6 is arranged at a position separated by a distance W2 from the main surface of the central partition wall 3 in the width direction of the circulating water channel, and the distance W2 is 1/3 to 2/2 of the total width W1 of the circulating water channel. 3 (see FIG. 4). The impeller 6 is arranged at such a position, and the substantially U-shaped rectifying plate 9 continues from both ends of the rectifying plate curved portion 9a and extends from the upstream side to the downstream side of the water flow in the circulating water path. By having the straight plate portion 9b, it is possible to suppress a decrease in the flow velocity of the water flow. Preferably, the length of straightening plate straight portion 9b in the direction in which peripheral wall 2 and the straight portions of circulation water passage and central partition wall 3 extend, strictly speaking, from the rotation center 6a of impeller 6 to the tip of straightening plate straight portion 9b , the length in the extending direction of the peripheral wall 2 and the straight portion of the circulating water channel and the central partition wall 3 is 1 to 3 times the maximum outer diameter D of the impeller 6 .

仮に、循環水路の幅方向において、インペラ６の回転中心６ａの中央区画壁３からの距離Ｗ２が循環水路の全幅の１／３未満である場合には、インペラ６が中央区画壁３に近すぎる。また、インペラ６の回転中心６ａの中央区画壁３からの距離Ｗ２が循環水路の全幅Ｗ１の２／３よりも大きい場合には、インペラ６が周囲壁２に近すぎる。いずれの場合にも、循環水路の水流を乱したり、部分的に循環水流に対する大きな抵抗を生じたりして、水流全体の流速を遅くする要因になる可能性がある。しかし、本実施形態では、前述したように、インペラ６の回転中心６ａと中央区画壁３との間の間隔Ｗ２が循環水路の全幅Ｗ１の１／３～２／３になるようにインペラ６を配置し、さらに整流板直線部９ｂが循環水路の長手方向に延びている。このような構成であると、循環水路の水流全体の流速があまり遅くならない。 If the distance W2 between the center of rotation 6a of the impeller 6 and the central dividing wall 3 in the width direction of the circulating water channel is less than 1/3 of the total width of the circulating water channel, the impeller 6 is too close to the central dividing wall 3. . Also, when the distance W2 from the center of rotation 6a of the impeller 6 to the central partition wall 3 is larger than 2/3 of the total width W1 of the circulating water passage, the impeller 6 is too close to the peripheral wall 2. In either case, the water flow in the circulating water channel may be disturbed, or a large resistance to the circulating water flow may be generated partially, thereby slowing down the flow velocity of the entire water flow. However, in this embodiment, as described above, the impeller 6 is arranged so that the distance W2 between the center of rotation 6a of the impeller 6 and the central partition wall 3 is 1/3 to 2/3 of the total width W1 of the circulating water passage. Further, the rectifying plate straight portion 9b extends in the longitudinal direction of the circulation water passage. With such a configuration, the flow velocity of the entire water flow in the circulation water channel does not become too slow.

なお、縦軸型エアレータ１１が設置される位置において、周囲壁２と中央区画壁３の互いに対向する面が局所的に突出して循環水路の幅が狭くなっている場合がある。例えば、図５に示すように、周囲壁２および中央区画壁３に局所的な凹凸部（突出部）２ｃ，３ａが設けられている場合がある。そのような場合にも、中央区画壁３の、局所的な凹凸部（突出部）３ａを除く面（主面）３ｂから、インペラ６の回転中心６ａまでの距離Ｗ２を、循環水路の全幅Ｗ１の１／３～２／３にする。一例としては、中央区画壁３の主面３ｂからインペラ６の回転中心６ａまでの距離Ｗ２が、循環水路の全幅Ｗ１の３／８である。そして、循環水路の幅が狭くなっている部分における中央区画壁３の突出部３ａからインペラ６の回転中心６ａまでの距離Ｗ４が、循環水路の全幅Ｗ１の１／５～１／３であることが好ましい。 At the position where the vertical shaft type aerator 11 is installed, the mutually facing surfaces of the peripheral wall 2 and the central partition wall 3 may locally protrude, narrowing the width of the circulating water passage. For example, as shown in FIG. 5, the peripheral wall 2 and the central partition wall 3 may be provided with local irregularities (protrusions) 2c and 3a. Even in such a case, the distance W2 from the surface (principal surface) 3b of the central partition wall 3 excluding the local irregularities (protrusions) 3a to the rotation center 6a of the impeller 6 is defined as the total width W1 of the circulating water passage. 1/3 to 2/3 of As an example, the distance W2 from the main surface 3b of the central partition wall 3 to the rotation center 6a of the impeller 6 is 3/8 of the full width W1 of the circulating water passage. Further, the distance W4 from the projecting portion 3a of the central partition wall 3 to the rotation center 6a of the impeller 6 in the portion where the width of the circulating water channel is narrowed is 1/5 to 1/3 of the total width W1 of the circulating water channel. is preferred.

また、仮に整流板直線部９ｂの、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さが、インペラ６の最大外径Ｄの１倍未満であると、インペラ６から下流側へ向かう水流の方向が安定せず、整流板直線部９ｂによる水流案内の効果が乏しい。整流板直線部９ｂの、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さが、インペラ６の最大外径Ｄの３倍程度であると、整流板直線部９ｂの水流案内の効果が十分に得られ、それ以上長くしてもその効果にさほど違いは生じない。そして、後述するように整流板直線部９ｂが周囲壁２の直線部分に対して斜めに延びる構成であると、整流板直線部９ｂが長過ぎると周囲壁２の内面に当接するか、周囲壁２の内面との間の間隔が小さくなりすぎて循環水流に対する大きな抵抗となるおそれがある。これらの状況を勘案すると、整流板直線部９ｂ（インペラ６の回転中心６ａから整流板直線部９ｂの先端までの範囲）の、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さが、インペラ６の最大外径Ｄの１～３倍であることが好ましい。 Further, if the length of straightening plate straight portion 9b in the direction in which peripheral wall 2, straight portions of circulating water passage, and central partition wall 3 extend is less than 1 time of maximum outer diameter D of impeller 6, The direction of the water flow toward the downstream side is not stable, and the effect of guiding the water flow by the straightening plate straight portion 9b is poor. When the length of the straightening plate straight portion 9b in the direction in which the peripheral wall 2, the straight portion of the circulating water passage, and the central partition wall 3 extend is about three times the maximum outer diameter D of the impeller 6, the straightening plate straight portion 9b The effect of guiding the water flow is sufficiently obtained, and even if the length is longer than that, the effect does not change so much. As will be described later, if the straight portion 9b of the straightening plate extends obliquely with respect to the straight portion of the peripheral wall 2, if the straight portion 9b of the straightening plate is too long, it will come into contact with the inner surface of the peripheral wall 2, There is a possibility that the distance between the inner surface of 2 becomes too small, resulting in a large resistance to the circulating water flow. In consideration of these circumstances, the direction in which the peripheral wall 2 and the straight portion of the circulating water passage and the central partition wall 3 of the flow straightening plate straight portion 9b (the range from the rotation center 6a of the impeller 6 to the tip of the straightening plate straight portion 9b) extends is preferably 1 to 3 times the maximum outer diameter D of the impeller 6.

図３に示す本実施形態の縦軸型エアレータ１１の整流板９は、反応タンク１の全深さに亘って設けられているわけではなく、インペラ６を覆う範囲とその上下のある程度の範囲のみに延びている。具体的には、インペラ６の上端と被処理水の液面１０（２点鎖線で図示）とが高さ方向にほぼ一致する位置にある場合、インペラ６の上端から整流板９の上端までの距離Ｈ１が、インペラ６の上端から整流板９の下端までの距離Ｈ２の１～１．５倍であることが好ましい。また、距離Ｈ２が、インペラ６の上端からインペラ６の下端までの距離Ｈ３の１．５～３倍であることが好ましい。このような構成により、本実施形態では、インペラ６の回転によって反応タンク１内に被処理液の循環水流を生じさせるとともに、活性汚泥の沈降を抑制して廃水と活性汚泥を十分に混合し、かつ被処理液に酸素を溶け込ませて生物学的処理を高効率で良好に行うことができる。さらに、インペラ６の回転によって被処理液の液面１０に加わる衝撃に起因する飛沫の周囲への飛散が整流板９によって一方向に整流され、かつ上流側から下流側への循環水流が良好に維持される。仮に整流板９が反応タンク１の全深さに亘って設けられていると、水流を完全に遮断するため、水流の乱れや流速の低下を引き起こすおそれがある。しかし、本実施形態では、前述したように整流板９の寸法を規定することで、整流の効果を維持しつつ、整流板９が水流を完全に遮断せず水流の乱れや流速の低下を抑制するという効果を奏することができる。 The rectifying plate 9 of the vertical shaft type aerator 11 of this embodiment shown in FIG. extends to Specifically, when the upper end of the impeller 6 and the liquid surface 10 of the water to be treated (illustrated by a chain double-dashed line) are at positions substantially aligned in the height direction, the distance from the upper end of the impeller 6 to the upper end of the current plate 9 is The distance H1 is preferably 1 to 1.5 times the distance H2 from the upper end of the impeller 6 to the lower end of the current plate 9. Further, it is preferable that the distance H2 is 1.5 to 3 times the distance H3 from the upper end of the impeller 6 to the lower end of the impeller 6. With such a configuration, in this embodiment, the rotation of the impeller 6 generates a circulating water flow of the liquid to be treated in the reaction tank 1, suppresses sedimentation of the activated sludge, and sufficiently mixes the wastewater and the activated sludge, In addition, oxygen can be dissolved in the liquid to be treated so that biological treatment can be carried out with high efficiency. Furthermore, the scattering of droplets caused by the impact applied to the liquid surface 10 of the liquid to be treated by the rotation of the impeller 6 is rectified in one direction by the rectifying plate 9, and the circulating water flow from the upstream side to the downstream side is improved. maintained. If the rectifying plate 9 were provided over the entire depth of the reaction tank 1, it would completely block the water flow, possibly causing turbulence in the water flow and a decrease in flow velocity. However, in the present embodiment, by specifying the dimensions of the rectifying plate 9 as described above, while maintaining the rectifying effect, the rectifying plate 9 does not completely block the water flow and suppresses turbulence of the water flow and a decrease in flow velocity. It is possible to achieve the effect of

オキシデーションディッチ装置において、高効率で良好な生物学的処理を行うために、被処理液の循環水流内に流速が１０ｃｍ／ｓｅｃを下回る部分が無いようにすることと、酸素供給量が２．２ｋｇ・Ｏ2／ｋＷｈ以上であることが望ましいことが知られている。本発明では、これらの条件を満たすために、インペラ６の回転中心６ａと、中央区画壁３の局所的な凹凸部３ａを除く主面３ｂとの間の間隔Ｗ２が、循環水路の全幅Ｗ１の１／３～２／３になるようにインペラ６を配置した。そして、縦軸型エアレータ１１が設置される位置において循環水路の幅が局所的に狭くなっている場合にも、中央区画壁３の局所的な凹凸部３ａを除く主面３ｂからインペラ６の回転中心６ａまでの距離Ｗ２が、循環水路の全幅Ｗ１の１／３～２／３、より好ましくは全幅Ｗ１の３／８程度になり、循環水路の幅が狭くなっている部分における中央区画壁３の局所的な凹凸部（突出部）３ａからインペラ６の回転中心６ａまでの距離Ｗ４が全幅Ｗ１の１／５～１／３になるように、インペラ６を配置した。さらに、整流板直線部９ｂの、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さを、インペラ６の最大外径Ｄの１～３倍にした。また、インペラ６の上端から整流板９の上端までの距離Ｈ１が、インペラ６の上端から整流板９の下端までの距離Ｈ２の１～１．５倍であって、この距離Ｈ２が、インペラ６の上端からインペラ６の下端までの距離Ｈ３の１．５～３倍になるようにした。本発明者は、これらの構成が、前述した望ましい流速および酸素供給量の条件を実現するために特に効果的であることを見出した。 In the oxidation ditch apparatus, in order to perform highly efficient and favorable biological treatment, there should be no part in the circulating water flow of the liquid to be treated where the flow velocity is less than 10 cm/sec, and the oxygen supply rate should be 2. It is known that 2 kg·O 2 /kWh or more is desirable. In the present invention, in order to satisfy these conditions, the distance W2 between the rotation center 6a of the impeller 6 and the main surface 3b of the central partition wall 3 excluding the local irregularities 3a is equal to the total width W1 of the circulating water passage. The impeller 6 was arranged so as to be 1/3 to 2/3. Further, even when the width of the circulating water passage is locally narrowed at the position where the vertical axis type aerator 11 is installed, the impeller 6 rotates from the main surface 3b excluding the local irregularities 3a of the central partition wall 3. The distance W2 to the center 6a is 1/3 to 2/3 of the total width W1 of the water circulation channel, more preferably about 3/8 of the total width W1, and the central partition wall 3 in the portion where the width of the water circulation channel is narrow The impeller 6 is arranged such that the distance W4 from the local irregularities (protrusions) 3a to the rotation center 6a of the impeller 6 is 1/5 to 1/3 of the overall width W1. Furthermore, the length of the linear portion 9b of the current plate in the extending direction of the peripheral wall 2, the linear portion of the circulating water passage, and the central partition wall 3 is set to 1 to 3 times the maximum outer diameter D of the impeller 6. Further, the distance H1 from the upper end of the impeller 6 to the upper end of the current plate 9 is 1 to 1.5 times the distance H2 from the upper end of the impeller 6 to the lower end of the current plate 9. 1.5 to 3 times the distance H3 from the upper end to the lower end of the impeller 6. The inventors have found these configurations to be particularly effective in achieving the desired flow rate and oxygenation requirements discussed above.

［第１の実施例］
図１，３，４に示す構成の具体例として、第１の実施例では、循環水路の全幅Ｗ１が４０００ｍｍであって少なくとも直線部分２ｂの位置において実質的に一定であり、インペラ６の回転中心６ａと中央区画壁３との間の間隔Ｗ２が１８００ｍｍ、整流板９の開口幅（整流板直線部９ｂの先端同士の間隔）Ｗ３が１８００ｍｍ、インペラ６の最大外径Ｄが１４００ｍｍ、整流板直線部９ｂ（インペラ６の回転中心６ａから整流板直線部９ｂの先端までの範囲）の、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さＬが３０００ｍｍである。本実施例では、１対の整流板直線部９ｂが平行であって、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に延びている。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は１５ｃｍ／ｓｅｃで、酸素供給量が２．２ｋｇ・Ｏ2／ｋＷｈ以上であり、高効率で良好な生物学的処理が実現した。なお、本実施例および後述する各実施例および各比較例において、流速の測定は、循環水路中で最も流速が低下しやすい図１のＡ部分、すなわち縦軸型エアレータ１１の上流側に位置する湾曲区画壁４の上流側端部付近において行った。本実施例および後述する第２～６の実施例では、図３に示すインペラ６の上端から整流板９の上端までの距離Ｈ１が６００ｍｍ、インペラ６の上端から整流板９の下端までの距離Ｈ２が５００ｍｍ、インペラ６の上端からインペラ６の下端までの距離Ｈ３が３００ｍｍである。 [First embodiment]
As a specific example of the configuration shown in FIGS. The distance W2 between 6a and the central partition wall 3 is 1800 mm, the opening width of the current plate 9 (the distance between the tips of the linear portions 9b of the current plate) W3 is 1800 mm, the maximum outer diameter D of the impeller 6 is 1400 mm, and the straight line of the current plate The length L of the portion 9b (range from the rotation center 6a of the impeller 6 to the tip of the rectifying plate straight portion 9b) in the extending direction of the peripheral wall 2, the straight portion of the circulating water passage, and the central partition wall 3 is 3000 mm. In this embodiment, the pair of straightening vane straight portions 9b are parallel and extend in the direction in which the peripheral wall 2, the straight portions of the circulating water channel, and the central partition wall 3 extend. When a circulation flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow rate is 15 cm/sec and the oxygen supply amount is 2.2 kg·O 2 /kWh or more, which is highly efficient and favorable. biological treatment was realized. In this example and each example and each comparative example described later, the flow velocity was measured at the portion A in FIG. It was performed near the upstream end of the curved partition wall 4 . In this embodiment and second to sixth embodiments described later, the distance H1 from the upper end of the impeller 6 to the upper end of the current plate 9 shown in FIG. is 500 mm, and the distance H3 from the upper end of the impeller 6 to the lower end of the impeller 6 is 300 mm.

［第２の実施例］
図６に示す第２の実施例では、循環水路の全幅Ｗ１が４０００ｍｍであって少なくとも直線部分２ｂの位置において実質的に一定であり、インペラ６の回転中心６ａと中央区画壁３との間の間隔Ｗ２が１８００ｍｍ、整流板９の開口幅Ｗ３が２５００ｍｍ、インペラ６の最大外径Ｄが１４００ｍｍ、整流板直線部９ｂの、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さＬが３０００ｍｍである。本実施例では、循環水路内の外側（周囲壁２に近い側）の整流板直線部９ｂが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に対してθ２（本実施例では１０度）だけ、整流板湾曲部９ａとの接続部から整流板直線部９の先端に向かうにつれて内側から外側に向かうように傾いている。従って、整流板９の開口幅Ｗ３が第１の実施例に比べて広がっている。長さＬは、整流板直線部９ｂの、それ自体が延びる方向の長さではなく、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さである。本実施例では、１対の整流板直線部９ｂの、それ自体が延びる方向の長さは異なっているが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さＬは一致している。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は２０ｃｍ／ｓｅｃで、酸素供給量が２．２ｋｇ・Ｏ2／ｋＷｈ以上であり、高効率で良好な生物学的処理が実現した。なお、角度θ２は、循環水路内の外側（周囲壁２に近い側）を正の値で、内側（中央区画壁３に近い側）を負の値でそれぞれ示す。 [Second embodiment]
In the second embodiment shown in FIG. 6, the total width W1 of the circulating water channel is 4000 mm and is substantially constant at least at the position of the straight portion 2b. The interval W2 is 1800 mm, the opening width W3 of the rectifying plate 9 is 2500 mm, the maximum outer diameter D of the impeller 6 is 1400 mm, and the linear portion of the peripheral wall 2 and the circulating water passage of the rectifying plate straight portion 9b and the central partition wall 3 extend Length L is 3000 mm. In this embodiment, the straight portion 9b of the current plate on the outer side (on the side closer to the surrounding wall 2) in the circulating water channel is set to θ2 (this embodiment 10 degrees in this example) from the connecting portion with the straightening plate curved portion 9a toward the tip of the straightening plate straight portion 9 from the inside toward the outside. Therefore, the opening width W3 of the straightening plate 9 is wider than that of the first embodiment. The length L is not the length in the direction in which the straightening plate straight portion 9b extends, but the length in the direction in which the peripheral wall 2, the straight portion of the circulating water channel, and the central partition wall 3 extend. In this embodiment, the lengths of the pair of rectifying plate straight portions 9b in the direction in which they themselves extend are different, but the length L are consistent. When a circulating flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow rate is 20 cm/sec and the oxygen supply amount is 2.2 kg·O 2 /kWh or more, which is highly efficient and favorable. biological treatment was realized. The angle θ2 indicates a positive value for the outside (closer to the peripheral wall 2) in the circulating water channel, and a negative value for the inside (closer to the central partition wall 3).

［第３の実施例］
図７に示す第３の実施例では、循環水路の全幅Ｗ１が４０００ｍｍであって少なくとも直線部分２ｂの位置において実質的に一定であり、インペラ６の回転中心６ａと中央区画壁３との間の間隔Ｗ２が１８００ｍｍ、整流板９の開口幅Ｗ３が１８００ｍｍ、インペラ６の最大外径Ｄが１４００ｍｍ、整流板直線部９ｂの周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さＬが３０００ｍｍである。本実施例では、１対の整流板直線部９ｂが平行であって、外側（周囲壁２に近い側）の整流板直線部９ｂが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に対してなす角度θ２と、内側（中央区画壁３に近い側）の整流板直線部９ｂが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に対してなす角度θ１とが一致しており、いずれも１０度である。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は２５ｃｍ／ｓｅｃで、酸素供給量が２．２ｋｇ・Ｏ2／ｋＷｈ以上であり、高効率で良好な生物学的処理が実現した。なお、角度θ１は、角度θ２と同様に、循環水路内の外側（周囲壁２に近い側）を正の値、内側（中央区画壁３に近い側）を負の値でそれぞれ示す。 [Third embodiment]
In the third embodiment shown in FIG. 7, the total width W1 of the circulating water channel is 4000 mm and is substantially constant at least at the position of the straight portion 2b. The interval W2 is 1800 mm, the opening width W3 of the straightening plate 9 is 1800 mm, the maximum outer diameter D of the impeller 6 is 1400 mm, the length in the extending direction of the peripheral wall 2 of the straight portion 9b of the straightening plate 9b, the straight portion of the circulating water passage, and the central partition wall 3. The length L is 3000 mm. In this embodiment, a pair of rectifying plate straight portions 9b are parallel, and the outer (side closer to the surrounding wall 2) rectifying plate straight portion 9b is connected to the surrounding wall 2, the straight portion of the circulating water channel, and the central partition wall 3. and the inner (closer to the central partition wall 3) flow straightening plate straight portion 9b make with the extending direction of the peripheral wall 2, the straight portion of the circulating water passage, and the central partition wall 3. The angle θ1 is the same, and both are 10 degrees. When a circulation flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow rate is 25 cm/sec and the oxygen supply amount is 2.2 kg·O 2 /kWh or more, which is highly efficient and favorable. biological treatment was realized. As with the angle θ2, the angle θ1 indicates a positive value for the outside (closer to the peripheral wall 2) in the circulating water channel, and a negative value for the inside (closer to the central partition wall 3).

［第４の実施例］
第３の実施例と類似した構成である第４の実施例では、図示しないが、インペラ６の回転中心６ａと中央区画壁３との間の間隔Ｗ２が２５００ｍｍであり、第３の実施例よりも外側（周囲壁２に近い側）にインペラ６および整流板９が配置されている。それ以外の構成は第３の実施例と同じである。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は１５ｃｍ／ｓｅｃで、酸素供給量が２．２ｋｇ・Ｏ2／ｋＷｈ以上であり、高効率で良好な生物学的処理が実現した。 [Fourth embodiment]
In the fourth embodiment, which has a configuration similar to that of the third embodiment, although not shown, the distance W2 between the rotation center 6a of the impeller 6 and the central partition wall 3 is 2500 mm. An impeller 6 and a rectifying plate 9 are arranged on the outer side (the side closer to the surrounding wall 2). Other configurations are the same as those of the third embodiment. When a circulation flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow rate is 15 cm/sec and the oxygen supply amount is 2.2 kg·O 2 /kWh or more, which is highly efficient and favorable. biological treatment was realized.

［第５の実施例］
図８に示す第５の実施例では、循環水路の全幅Ｗ１が４０００ｍｍであって少なくとも直線部分２ｂの位置において実質的に一定であり、インペラ６の回転中心６ａと中央区画壁３との間の間隔Ｗ２が１８００ｍｍ、整流板９の開口幅Ｗ３が１５００ｍｍ、インペラ６の最大外径Ｄが１４００ｍｍ、整流板直線部９ｂの、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さＬが３０００ｍｍである。本実施例では、外側の整流板直線部９ｂが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に対してなす角度θ２が１０度であって、内側の整流板直線部９ｂが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に対してなす角度θ１が１５度である。角度θ１が角度θ２よりも大きいため、整流板９の開口幅Ｗ３が第１の実施例に比べて狭くなっており、１対の整流板直線部９ｂに挟まれた空間は、整流板湾曲部９ａとの接続部から整流板直線部９の先端に向かうにつれて内側から外側に向かうように傾いている。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は３０ｃｍ／ｓｅｃで、酸素供給量が２．２ｋｇ・Ｏ2／ｋＷｈ以上であり、高効率で良好な生物学的処理が実現した。 [Fifth embodiment]
In the fifth embodiment shown in FIG. 8, the total width W1 of the circulating water channel is 4000 mm and is substantially constant at least at the position of the straight portion 2b, and the distance between the rotation center 6a of the impeller 6 and the central partition wall 3 is 4000 mm. The interval W2 is 1800 mm, the opening width W3 of the straightening plate 9 is 1500 mm, the maximum outer diameter D of the impeller 6 is 1400 mm, and the straight portion of the straight portion 9b of the straightening plate 9b, the peripheral wall 2, the straight portions of the circulating water passage, and the central partition wall 3 extend. Length L is 3000 mm. In this embodiment, the angle θ2 formed by the outer flow straightening plate straight portion 9b with respect to the extending direction of the peripheral wall 2, the straight portion of the circulating water channel, and the central partition wall 3 is 10 degrees, and the inner straightening plate straight portion The angle θ1 formed by 9b with respect to the extending direction of the peripheral wall 2, the straight portion of the circulating water channel, and the central partition wall 3 is 15 degrees. Since the angle θ1 is larger than the angle θ2, the opening width W3 of the rectifying plate 9 is narrower than that of the first embodiment, and the space sandwiched between the pair of rectifying plate straight portions 9b is the curved portion of the rectifying plate. It inclines from the inside to the outside as it goes from the connecting portion with 9a to the tip of straight portion 9 of straightening plate. When a circulating flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow rate is 30 cm/sec, the oxygen supply amount is 2.2 kg·O 2 /kWh or more, and it is highly efficient and good. biological treatment was realized.

［第６の実施例］
図９に示す第６の実施例では、循環水路の全幅Ｗ１が４０００ｍｍであって少なくとも直線部分２ｂの位置において実質的に一定であり、インペラ６の回転中心６ａと中央区画壁３との間の間隔Ｗ２が１８００ｍｍ、整流板９の開口幅Ｗ３が１４００ｍｍ、インペラ６の最大外径Ｄが１４００ｍｍ、整流板直線部９ｂの、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さＬが３０００ｍｍである。本実施例では、外側の整流板直線部９ｂが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に対してなす角度θ２が０度、すなわち平行である。それに対して、内側の整流板直線部９ｂが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に対してなす角度θ１が１０度である。角度θ１が角度θ２よりも大きいため、整流板９の開口幅Ｗ３が第１の実施例に比べて狭くなっており、１対の整流板直線部９ｂに挟まれた空間は、整流板湾曲部９ａとの接続部から整流板直線部９の先端に向かうにつれて内側から外側に向かうように傾いている。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は１８ｃｍ／ｓｅｃで、酸素供給量が２．２ｋｇ・Ｏ2／ｋＷｈ以上であり、高効率で良好な生物学的処理が実現した。 [Sixth embodiment]
In the sixth embodiment shown in FIG. 9, the total width W1 of the circulating water channel is 4000 mm and is substantially constant at least at the position of the straight portion 2b, and the distance between the rotation center 6a of the impeller 6 and the central partition wall 3 is The distance W2 is 1800 mm, the opening width W3 of the rectifying plate 9 is 1400 mm, the maximum outer diameter D of the impeller 6 is 1400 mm, and the linear portion of the rectifying plate straight portion 9b, the peripheral wall 2, the straight portions of the circulating water passage, and the central partition wall 3 extend. Length L is 3000 mm. In this embodiment, the angle .theta.2 formed by the outer rectifying plate straight portion 9b with respect to the extending direction of the peripheral wall 2, the straight portion of the circulating water channel, and the central partition wall 3 is 0 degrees, that is, parallel. On the other hand, the angle θ1 formed by the inner rectifying plate straight portion 9b with respect to the extending direction of the peripheral wall 2, the straight portion of the circulating water channel, and the central partition wall 3 is 10 degrees. Since the angle θ1 is larger than the angle θ2, the opening width W3 of the rectifying plate 9 is narrower than that of the first embodiment, and the space sandwiched between the pair of rectifying plate straight portions 9b is the curved portion of the rectifying plate. It inclines from the inside to the outside as it goes from the connecting portion with 9a to the tip of straight portion 9 of straightening plate. When a circulation flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow rate is 18 cm/sec and the oxygen supply amount is 2.2 kg·O 2 /kWh or more, which is highly efficient and favorable. biological treatment was realized.

［第１の比較例］
第１の実施例と類似した構成である第１の比較例では、図示しないが、インペラ６の回転中心６ａと中央区画壁３との間の間隔Ｗ２が１０００ｍｍであり、第１の実施例よりも外側（周囲壁２に近い側）にインペラ６および整流板９が配置されている。それ以外の構成は第１の実施例と同じである。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は６．５ｃｍ／ｓｅｃであり、高効率で良好な生物学的処理が実現できない場合がある。これは、インペラ６が中央区画壁３に近すぎて流速が遅くなったことが原因であると考えられる。 [First Comparative Example]
In the first comparative example, which has a configuration similar to that of the first example, although not shown, the interval W2 between the rotation center 6a of the impeller 6 and the central partition wall 3 is 1000 mm. An impeller 6 and a rectifying plate 9 are arranged on the outer side (the side closer to the surrounding wall 2). Other configurations are the same as those of the first embodiment. When a circulating flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow velocity is 6.5 cm/sec, and there are cases where highly efficient and favorable biological treatment cannot be achieved. It is believed that this is because the impeller 6 is too close to the central partition wall 3 and the flow velocity becomes slow.

［第２の比較例］
第１の実施例と類似した構成である第２の比較例では、図示しないが、整流板直線部９ｂの周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向における長さＬが１０００ｍｍである。それ以外の構成は第１の実施例と同じである。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は３ｃｍ／ｓｅｃであり、高効率で良好な生物学的処理が実現できない場合がある。本比較例ではＬ＜Ｄであり、整流板直線部９ｂが短すぎるためにあまり良好な結果が得られなかったと考えられる。 [Second Comparative Example]
In a second comparative example having a configuration similar to that of the first embodiment, although not shown, the length L in the extending direction of the peripheral wall 2 of the straightening plate straight portion 9b, the straight portion of the circulating water passage, and the central partition wall 3 is 1000 mm. Other configurations are the same as those of the first embodiment. When a circulating flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow velocity is 3 cm/sec, and there are cases where highly efficient and favorable biological treatment cannot be achieved. In this comparative example, L<D, and it is considered that the rectifying plate linear portion 9b was too short, so that a very good result was not obtained.

［第３の比較例］
第１の実施例と類似した構成である第３の比較例では、図示しないが、インペラ６の回転中心６ａと中央区画壁３との間の間隔Ｗ２が１０００ｍｍであり、第１の実施例よりも内側（中央区画壁３に近い側）にインペラ６および整流板９が配置されている。それ以外の構成は第１の実施例と同じである。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は５ｃｍ／ｓｅｃであり、高効率で良好な生物学的処理が実現できない場合がある。本比較例ではＷ２＜Ｗ１×１／３であり、インペラ６が中央区画壁３に近すぎるためにあまり良好な結果が得られなかったと考えられる。 [Third Comparative Example]
In a third comparative example having a configuration similar to that of the first example, although not shown, the distance W2 between the rotation center 6a of the impeller 6 and the central partition wall 3 is 1000 mm, and An impeller 6 and a rectifying plate 9 are arranged on the inner side (the side closer to the central partition wall 3). Other configurations are the same as those of the first embodiment. When a circulating flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow velocity is 5 cm/sec, and there are cases where highly efficient and favorable biological treatment cannot be achieved. In this comparative example, W2<W1×1/3, and it is considered that the impeller 6 was too close to the central partition wall 3, so that a very good result was not obtained.

［第４の比較例］
第２の実施例と類似した構成である第４の比較例では、図１０に示すように、循環水路内の外側（周囲壁２に近い側）の整流板直線部９ｂが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に対してなす角度θ２が－１０度である。従って、外側の整流板直線部９ｂは、整流板湾曲部９ａとの接続部から整流板直線部９の先端に向かうにつれて外側から内側に向かうように傾いている。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は５ｃｍ／ｓｅｃであり、高効率で良好な生物学的処理が実現できない場合がある。本比較例では１対の整流板直線部９ｂの間から流れる水流が、循環水流の流束が速い循環水路の外側（周囲壁２に近い側）ではなく、流束が遅い内側（中央区画壁３に近い側）に向かうために、あまり良好な結果が得られなかったと考えられる。 [Fourth Comparative Example]
In a fourth comparative example having a configuration similar to that of the second example, as shown in FIG. The angle θ2 formed with the straight portion of the circulating water channel and the extending direction of the central partition wall 3 is −10 degrees. Therefore, the outer straight portion 9b of the straightening plate is inclined from the outside toward the inside from the connecting portion with the curved portion 9a of the straightening plate toward the tip of the straight portion 9 of the straightening plate. When a circulating flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow velocity is 5 cm/sec, and there are cases where highly efficient and favorable biological treatment cannot be achieved. In this comparative example, the water flow flowing between the pair of rectifying plate straight portions 9b is not on the outside of the circulating water channel (closer to the surrounding wall 2) where the flux of the circulating water flow is fast, but on the inner side (the central partition wall) where the flow is slow. 3), it is thought that not very good results were obtained.

［第５の比較例］
第６の実施例と類似した構成である第５の比較例では、図示しないが、循環水路内の内側（中央区画壁９に近い側）の整流板直線部９ｂが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に対してなす角度θ１が４０度である。従って、内側の整流板直線部９ｂは、整流板湾曲部９ａとの接続部から整流板直線部９の先端に向かうにつれて内側から外側に向かうように傾いている。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は８ｃｍ／ｓｅｃであり、高効率で良好な生物学的処理が実現できない場合がある。このことから、整流板直線部９ｂが、周囲壁２および循環水路の直線部分並びに中央区画壁３の延びる方向に対してなす角度θ１が大きすぎると好ましくないことがわかる。実験的に確認したところ、角度θ１は好ましくは０～３０度、より好ましくは１０～２０度に設定するとよいことが判った。角度θ２についても同様に、好ましくは０～３０度、より好ましくは１０～２０度に設定するとよいことが実験的に判った。 [Fifth Comparative Example]
In the fifth comparative example, which has a configuration similar to that of the sixth embodiment, although not shown, the inner (closer to the central partition wall 9) flow straightening plate straight portion 9b in the circulation water channel is located between the surrounding wall 2 and the circulation water channel. and the direction in which the central partition wall 3 extends is 40 degrees. Therefore, the inner straight portion 9b of the straightening plate is inclined from the inside toward the outside from the connecting portion with the curved portion 9a of the straightening plate toward the tip of the straight portion 9 of the straightening plate. When a circulating flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow velocity is 8 cm/sec, and there are cases where highly efficient and favorable biological treatment cannot be achieved. From this, it can be seen that it is not preferable that the angle θ1 formed by the rectifying plate straight portion 9b with respect to the extending direction of the peripheral wall 2, the straight portion of the circulating water channel, and the central partition wall 3 is too large. As a result of experimental confirmation, it was found that the angle θ1 should preferably be set to 0 to 30 degrees, more preferably 10 to 20 degrees. Similarly, it was found experimentally that the angle θ2 should preferably be set to 0 to 30 degrees, more preferably 10 to 20 degrees.

［第７の実施例］
第３の実施例と類似した構成である第７の実施例では、図３に示すインペラ６の上端から整流板９の上端までの距離Ｈ１が３００ｍｍ、インペラ６の上端から整流板９の下端までの距離Ｈ２が３００ｍｍ、インペラ６の上端からインペラ６の下端までの距離Ｈ３が２００ｍｍである。それ以外の構成は第３の実施例と同じである。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は２０ｃｍ／ｓｅｃで、酸素供給量が２．２ｋｇ・Ｏ2／ｋＷｈ以上であり、高効率で良好な生物学的処理が実現した。 [Seventh embodiment]
In the seventh embodiment, which has a configuration similar to that of the third embodiment, the distance H1 from the upper end of the impeller 6 to the upper end of the current plate 9 shown in FIG. is 300 mm, and the distance H3 from the upper end of the impeller 6 to the lower end of the impeller 6 is 200 mm. Other configurations are the same as those of the third embodiment. When a circulating flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow rate is 20 cm/sec and the oxygen supply amount is 2.2 kg·O 2 /kWh or more, which is highly efficient and favorable. biological treatment was realized.

［第６の比較例］
第３の実施例と類似した構成である第６の比較例では、図３に示すインペラ６の上端から整流板９の上端までの距離Ｈ１が０ｍｍ、インペラ６の上端から整流板９の下端までの距離Ｈ２が５００ｍｍ、インペラ６の上端からインペラ６の下端までの距離Ｈ３が３００ｍｍである。それ以外の構成は第７の実施例と同じである。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は５ｃｍ／ｓｅｃであり、高効率で良好な生物学的処理が実現できない場合がある。本比較例では整流板９の上端がインペラ６の上端および水面１０と同じ高さに位置しており、インペラの回転により上流側へ向かう波や飛沫を十分に遮られないため、あまり良好な結果が得られなかったと考えられる。 [Sixth Comparative Example]
In a sixth comparative example having a configuration similar to that of the third embodiment, the distance H1 from the upper end of the impeller 6 to the upper end of the current plate 9 shown in FIG. is 500 mm, and the distance H3 from the upper end of the impeller 6 to the lower end of the impeller 6 is 300 mm. Other configurations are the same as those of the seventh embodiment. When a circulating flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow velocity is 5 cm/sec, and there are cases where highly efficient and favorable biological treatment cannot be achieved. In this comparative example, the upper end of the rectifying plate 9 is positioned at the same height as the upper end of the impeller 6 and the water surface 10, and the rotation of the impeller does not sufficiently block the waves and splashes going upstream, so the results are not very good. was not obtained.

［第７の比較例］
第３の実施例と類似した構成である第７の比較例では、図３に示すインペラ６の上端から整流板９の上端までの距離Ｈ１が６００ｍｍ、インペラ６の上端から整流板９の下端までの距離Ｈ２が０ｍｍ、インペラ６の上端からインペラ６の下端までの距離Ｈ３が３００ｍｍである。それ以外の構成は第３の実施例と同じである。このオキシデーションディッチ装置の反応タンク１内に被処理液の循環流を発生させると、その流速は７ｃｍ／ｓｅｃであり、高効率で良好な生物学的処理が実現できない場合がある。本比較例では整流板９がインペラ６自体を覆っておらず、インペラ６の回転により水面下で上流側へ向かう被処理液の流れが遮られないため、あまり良好な結果が得られなかったと考えられる。 [Seventh Comparative Example]
In a seventh comparative example having a configuration similar to that of the third embodiment, the distance H1 from the upper end of the impeller 6 to the upper end of the current plate 9 shown in FIG. is 0 mm, and the distance H3 from the upper end of the impeller 6 to the lower end of the impeller 6 is 300 mm. Other configurations are the same as those of the third embodiment. When a circulating flow of the liquid to be treated is generated in the reaction tank 1 of this oxidation ditch apparatus, the flow velocity is 7 cm/sec, and there are cases where highly efficient and favorable biological treatment cannot be achieved. In this comparative example, the straightening plate 9 does not cover the impeller 6 itself, and the rotation of the impeller 6 does not block the flow of the liquid to be treated toward the upstream side under the water surface. be done.

［第８の実施例］
図１１に示す第８の実施例では、１対の整流板直線部９ｂのうち、中央区画壁３側に位置する整流板直線部９ｂは、図７～９に示す第３～６の実施例と同様に、整流板湾曲部９ａとの接続部から整流板直線部９ｂの先端に向かうにつれて、中央区画壁３側から周囲壁２側に向かうように傾いている。一方、周囲壁２側に位置する整流板直線部９ｂは、整流板湾曲部９ａとの接続部から整流板直線部９ｂの先端に向かうにつれて周囲壁２側から中央区画壁３側に向かうように傾いている。ただし、周囲壁２側に位置する整流板直線部９ｂの、周囲壁２側から中央区画壁３側に向かう傾き角度の絶対値は、中央区画壁３側に位置する整流板直線部９ｂの、中央区画壁３側から周囲壁２側に向かう傾き角度の絶対値よりも小さい。本発明では、インペラ６および整流板９によって、外側向きの流れ、すなわち循環水路の流れの上流側から下流側に向かうにつれて中央区画壁３側から周囲壁２側に向かう流れを生じさせることで、水流の乱れや流速の低下を抑える。そのために、少なくとも中央区画壁３側に位置する整流板直線部９ｂを、循環水路の流れに沿って中央区画壁３側から周囲壁２側に向かうように傾けている。ただし、周囲壁２側に位置する整流板直線部９ｂに関しては、その反対向き、すなわち循環水路の流れに沿って周囲壁２側から中央区画壁３側に向かうように僅かに傾いている構成もある程度許容できる。その場合、少なくとも、周囲壁２側に位置する整流板直線部９ｂの内側向きの傾き角度の絶対値が、中央区画壁３側に位置する整流板直線部９ｂの外側向きの傾き角度の絶対値よりも小さくなければならない。 [Eighth embodiment]
In the eighth embodiment shown in FIG. 11, of the pair of straightening plate straight portions 9b, the straightening plate straight portion 9b located on the side of the central partition wall 3 is the same as in the third to sixth embodiments shown in FIGS. Similarly, it is inclined from the central partition wall 3 side toward the peripheral wall 2 side from the connecting portion with the straightening plate curved portion 9a toward the tip of the straightening plate straight portion 9b. On the other hand, the rectifying plate straight portion 9b located on the side of the peripheral wall 2 is arranged so as to move from the peripheral wall 2 side to the central partition wall 3 side as it goes from the connecting portion with the rectifying plate curved portion 9a to the tip of the straightening plate straight portion 9b. leaning However, the absolute value of the inclination angle from the peripheral wall 2 side to the central partition wall 3 side of the straightening plate straight portion 9b positioned on the side of the peripheral wall 2 is It is smaller than the absolute value of the inclination angle from the central partition wall 3 side to the peripheral wall 2 side. In the present invention, the impeller 6 and the rectifying plate 9 generate an outward flow, that is, a flow from the central partition wall 3 side to the peripheral wall 2 side as the flow of the circulating water channel goes from the upstream side to the downstream side, Suppress turbulence of water flow and decrease in flow velocity. For this reason, at least the rectifying plate straight portion 9b located on the central partition wall 3 side is inclined from the central partition wall 3 side toward the peripheral wall 2 side along the flow of the circulating water channel. However, the rectifying plate straight portion 9b located on the side of the peripheral wall 2 may be slightly inclined in the opposite direction, that is, along the flow of the circulating water path from the side of the peripheral wall 2 toward the side of the central partition wall 3. acceptable to some extent. In this case, at least the absolute value of the inward tilt angle of the straight plate straight portion 9b positioned on the side of the peripheral wall 2 is the absolute value of the outward tilt angle of the straight plate straight portion 9b positioned on the central partition wall 3 side. must be less than

前述した第３～８の実施形態では、１対の整流板直線部９ｂに挟まれた空間は、整流板湾曲部９ａとの接続部から整流板直線部９の先端に向かうにつれて内側から外側に向かうように傾いている。すなわち、１対の整流板直線部９ｂに挟まれた空間からの流れは、外側に向かっているという点で有利である。その理由について説明すると、長円状の周囲壁と中央区画壁３とに囲まれた循環水路を流れる循環流は、外側（周囲壁２側）において流速が速く、内側（中央区画壁３側）において流速が遅い傾向がある。そのような状態で、内側の流速の遅い部分に被処理液の多くを供給して推進力を加えて速くしようとしても、効果的ではない（例えば第４の比較例）のに対し、外側の流速の速い部分に被処理液の多くを供給すると、循環流全体の流速を高める効果が得やすい（例えば第６の実施例）ことが実験により判明した。従って、１対の整流板直線部９ｂに挟まれた空間から送られる流れが、循環水路の外側の流速の速い部分に向けられると、流速の向上をもたらしやすい。特に、湾曲区画壁４が設けられている構成では、湾曲区画壁４の内側と外側とで流速の差が生じやすい。従って、１対の整流板直線部９ｂに挟まれた空間から送られる流れが、湾曲区画壁４の外側に向くように設定することが好ましい。具体的には、図８の要部の拡大図である図１２に示すように、１対の整流板直線部９ｂを延長した仮想線９ｂ１がいずれも、湾曲区画壁４の内側ではなく外側に進入するような角度に形成されていることが好ましい。さらに、１対の整流板直線部９ｂに挟まれた空間から送られる流れがより確実に湾曲区画壁４の外側に送られるためには、周囲壁２から、循環流路の全幅Ｗ１の１／３以下の距離だけしか離れていない範囲内に、１対の整流板直線部９ｂを延長した仮想線９ｂ１がいずれも進入することが好ましい。仮に、湾曲区画壁４が循環水流の中心からずれた位置に配置されている場合にも、１対の整流板直線部９ｂを延長した仮想線９ｂ１がいずれも、湾曲区画壁４で２系統に分割される水路のうちの外側の水路に進入するように配置されることが好ましい。ただし、整流板直線部９ｂが水流に対する大きな抵抗となることがないように、その傾き角度は３０度以下にすることが好ましい。 In the above-described third to eighth embodiments, the space sandwiched between the pair of rectifying plate straight portions 9b extends from the inside to the outside as it goes from the connection with the rectifying plate curved portion 9a to the tip of the rectifying plate straight portion 9. It's tilted towards you. That is, it is advantageous in that the flow from the space sandwiched between the pair of rectifying plate straight portions 9b is directed outward. The reason for this is that the circulation flow flowing through the circulation channel surrounded by the oval peripheral wall and the central partition wall 3 has a high flow velocity on the outside (surrounding wall 2 side) and the inside (central partition wall 3 side). flow velocity tends to be slow in In such a state, it is not effective (for example, the fourth comparative example) to supply a large amount of the liquid to be treated to the inner portion where the flow rate is slow to increase the flow rate by applying a driving force. It has been found by experiments that the effect of increasing the flow velocity of the entire circulating flow is likely to be obtained when most of the liquid to be treated is supplied to the portion where the flow velocity is high (for example, the sixth embodiment). Therefore, if the flow sent from the space sandwiched between the pair of straightening vane straight portions 9b is directed to the portion where the flow speed is high outside the circulating water channel, the flow speed is likely to be improved. In particular, in a configuration in which the curved partition wall 4 is provided, a difference in flow velocity is likely to occur between the inside and the outside of the curved partition wall 4 . Therefore, it is preferable to set the flow sent from the space sandwiched between the pair of rectifying plate straight portions 9 b to the outside of the curved partition wall 4 . Specifically, as shown in FIG. 12, which is an enlarged view of the essential part of FIG. It is preferably formed at an angle for entering. Furthermore, in order for the flow sent from the space sandwiched between the pair of rectifying plate straight portions 9b to be more reliably sent to the outside of the curved partition wall 4, the peripheral wall 2 must have a width of 1/ of the total width W1 of the circulation flow path. It is preferable that the imaginary lines 9b1 extending from the pair of rectifying plate straight portions 9b all enter within a range separated by a distance of 3 or less. Even if the curved partition wall 4 is arranged at a position deviated from the center of the circulating water flow, the virtual lines 9b1 extending from the pair of straightening plate straight portions 9b are all divided into two systems by the curved partition wall 4. It is preferably arranged to enter the outer channel of the channel being divided. However, the inclination angle is preferably 30 degrees or less so that the linear portion 9b of the rectifying plate does not become a large resistance to the water flow.

［他の実施形態］
前述した各構成では、長円形状の循環水路を構成する反応タンク１を用いているが、本発明はこのような構成に限定されない。例えば、楕円形状や変形した環状の反応タンク等が設けられていてもよい。また、図１３に示すように、２つの長円形状が一部で連結されたような馬蹄形であって、内部にＵ字状の中央区画壁１３を有する反応タンク１２を用いてもよい。いずれの場合にも、循環水路のうちの実質的に直線状の部分に、本発明の縦軸型エアレータ１１を含む曝気撹拌システムを配置すればよい。この曝気撹拌システムは循環水路中に複数個設けられていてもよい。湾曲区画壁４は必ずしも設けられていなくてもよい。また、循環水流が時計方向ではなく反時計方向である場合には、本発明の各図面に記載した構成を左右対称に反転させた形状にすればよい。 [Other embodiments]
In each of the configurations described above, the reaction tank 1 forming an oval circulating water channel is used, but the present invention is not limited to such a configuration. For example, an elliptical or deformed annular reaction tank or the like may be provided. Alternatively, as shown in FIG. 13, a reaction tank 12 having a horseshoe shape formed by partially connecting two oval shapes and having a U-shaped central partition wall 13 inside may be used. In either case, the aeration agitation system including the vertical axis aerator 11 of the present invention may be placed in a substantially straight portion of the circulating waterway. A plurality of this aeration stirring system may be provided in the circulating water channel. The curved partition wall 4 may not necessarily be provided. Further, when the circulating water flow is counterclockwise instead of clockwise, the configuration described in each drawing of the present invention may be symmetrically reversed.

１ 反応タンク
２ 周囲壁
２ａ 湾曲部分
２ｂ 直線部分
３ 中央区画壁
４ 湾曲区画壁
５ 回転軸
６ インペラ
６ａ 回転中心
７ 電動機
８ 減速機
９ 整流板
９ａ 整流板湾曲部
９ｂ 整流板直線部
９ｂ１ 仮想線
１０ 被処理水の液面
１１ 縦軸型エアレータ 1 Reaction tank 2 Surrounding wall 2a Curved portion 2b Straight portion 3 Central partition wall 4 Curved partition wall 5 Rotating shaft 6 Impeller 6a Rotation center 7 Electric motor 8 Reduction gear 9 Straightening plate 9a Straightening plate curved portion 9b Straightening plate straight portion 9b1 Virtual line 10 Surface of treated water 11 Vertical shaft type aerator

Claims (11)

周囲壁と前記周囲壁の内側に位置する中央区画壁とによって少なくとも一部に直線部分を含む被処理水の循環水路を構成する反応タンクの内部に配置される曝気撹拌システムであって、
前記循環水路の前記直線部分に配置された、垂直軸を中心として回転可能なインペラと、前記インペラを、一部を除いて囲むように配置された整流板とを有し、
前記整流板は、前記反応タンクを流れる循環水流の前記直線部分における前記インペラの上流側に向かって凸状の整流板湾曲部と、前記整流板湾曲部の両端から循環水流の前記直線部分における前記インペラの下流側に直線的に延びる１対の整流板直線部とを有し、
前記インペラは、前記上流側において前記整流板湾曲部に覆われ、前記下流側においては１対の前記整流板直線部の間で開放されており、
前記インペラの回転中心が、前記循環水路の幅方向において、前記中央区画壁の主面から、前記循環水路の全幅の１／３～２／３の距離だけ離れた位置に配置されている、曝気撹拌システム。 An aeration agitation system arranged inside a reaction tank that forms a circulation channel for the water to be treated, at least partially including a straight portion, by a peripheral wall and a central partition wall located inside the peripheral wall,
An impeller arranged in the linear portion of the circulating water passage and rotatable about a vertical axis ;
The flow straightening plate includes a straightening plate curved portion protruding toward the upstream side of the impeller in the linear portion of the circulating water flow flowing through the reaction tank, and a straightening plate curved portion protruding toward the upstream side of the impeller, a pair of rectifying plate straight portions extending linearly downstream of the impeller ,
The impeller is covered with the straightening plate curved portion on the upstream side, and is open between the pair of straightening plate straight portions on the downstream side,
Aeration, wherein the center of rotation of the impeller is located at a distance of 1/3 to 2/3 of the overall width of the circulating water channel from the main surface of the central partition wall in the width direction of the circulating water channel. Agitation system. 前記インペラの回転中心から前記整流板直線部の先端までの、前記循環水路の前記直線部分の延びる方向における長さが、前記インペラの最大外径の１～３倍である、請求項１に記載の曝気撹拌システム。 2. The method according to claim 1, wherein the length in the direction in which the linear portion of the circulating water passage extends from the center of rotation of the impeller to the tip of the linear portion of the current plate is 1 to 3 times the maximum outer diameter of the impeller. aeration agitation system. １対の前記整流板直線部のうち少なくとも前記中央区画壁側に位置する前記整流板直線部は、前記整流板湾曲部との接続部から前記整流板直線部の先端に向かうにつれて前記中央区画壁側から前記周囲壁側に向かうように傾いており、その傾き角度は３０度以下である、請求項１または２に記載の曝気撹拌システム。 Of the pair of straightening plate straight portions, the straightening plate straight portion positioned at least on the side of the central partition wall is inclined toward the central partitioning wall from a connection portion with the straightening plate curved portion toward the tip of the straightening plate straight portion. 3. The aeration and agitation system according to claim 1, wherein the aeration and agitation system is inclined from the side toward the peripheral wall side, and the inclination angle is 30 degrees or less. １対の前記整流板直線部がいずれも、前記整流板湾曲部との接続部から前記整流板直線部の先端に向かうにつれて前記中央区画壁側から前記周囲壁側に向かうように傾いており、前記中央区画壁側に位置する前記整流板直線部の、前記循環水路の直線部分の延びる方向に対する角度が、前記周囲壁側に位置する前記整流板直線部の、前記循環水路の前記直線部分の延びる方向に対する角度よりも大きい、請求項３に記載の曝気撹拌システム。 Both of the pair of straightening plate straight portions are inclined from the central partition wall side toward the peripheral wall side from the connecting portion with the straightening plate curved portion toward the tip of the straightening plate straight portion, The angle of the straightening plate straight portion located on the central partition wall side with respect to the extending direction of the straight portion of the circulating water channel is the angle of the straightening plate straight portion located on the peripheral wall side of the straight portion of the circulating water channel. 4. The aeration agitation system of claim 3, wherein the angle with respect to the direction of extension is greater. １対の前記整流板直線部のうち、前記周囲壁側に位置する前記整流板直線部は、前記整流板湾曲部との接続部から前記整流板直線部の先端に向かうにつれて前記周囲壁側から前記中央区画壁側に向かうように傾いており、その傾き角度の絶対値は、前記中央区画壁側に位置する前記整流板直線部の、前記整流板湾曲部との接続部から前記整流板直線部の先端に向かうにつれて前記中央区画壁側から前記周囲壁側に向かうように傾く傾き角度の絶対値よりも小さい、請求項３に記載の曝気撹拌システム。 Of the pair of straightening plate straight portions, the straightening plate straight portion located on the side of the peripheral wall is inclined from the peripheral wall side toward the tip of the straightening plate straight portion from the connection portion with the straightening plate curved portion. It is inclined toward the central partition wall side, and the absolute value of the inclination angle is the straight line portion of the straightening plate located on the central partition wall side from the connection portion of the straightening plate curved portion to the straightening plate straight line. 4. The aeration agitation system according to claim 3, which is smaller than the absolute value of the inclination angle from the central partition wall side toward the peripheral wall side toward the tip of the portion. 前記循環水路の深さ方向において、前記インペラの上端から前記整流板の上端までの距離が、前記インペラの上端から前記整流板の下端までの距離の１～１．５倍であり、かつ前記インペラの上端から前記整流板の下端までの距離が、前記インペラの上端から該インペラの下端までの距離の１．５～３倍である、請求項１から５のいずれか１項に記載の曝気撹拌システム。 The distance from the upper end of the impeller to the upper end of the rectifying plate in the depth direction of the circulating water passage is 1 to 1.5 times the distance from the upper end of the impeller to the lower end of the rectifying plate, and The aeration stirring according to any one of claims 1 to 5, wherein the distance from the upper end to the lower end of the current plate is 1.5 to 3 times the distance from the upper end of the impeller to the lower end of the impeller. system. 請求項１から６のいずれか１項に記載の曝気撹拌システムと、前記反応タンクと、を有する、オキシデーションディッチ装置。 An oxidation ditch apparatus comprising the aeration stirring system according to any one of claims 1 to 6 and the reaction tank. 前記反応タンクの前記中央区画壁の両端はいずれも前記周囲壁の内面から間隔を置いて位置しており、前記中央区画壁の端部と前記周囲壁の内面との間の間隔を通って、前記中央区画壁の両側へ延びる湾曲区画壁が設けられており、
前記湾曲区画壁は前記循環水路の一部を２系統に分割しており、
１対の前記整流板直線部を延長した仮想線がいずれも、前記湾曲区画壁で２系統に分割された前記循環水路のうちの外側の水路に進入するように、前記整流板が配置されている、請求項７に記載のオキシデーションディッチ装置。 Both ends of the central partition wall of the reaction tank are spaced apart from the inner surface of the peripheral wall, and through the gap between the end of the central partition wall and the inner surface of the peripheral wall, A curved partition wall extending to both sides of the central partition wall is provided,
The curved partition wall divides a part of the circulating water channel into two systems,
The flow straightening vanes are arranged such that virtual lines extending from the pair of straight straight portions of the straightening vanes enter the outer water channel of the circulation water channels divided into two systems by the curved partition wall. 8. The oxidation ditch apparatus of claim 7, comprising: 周囲壁と前記周囲壁の内側に位置する中央区画壁とによって少なくとも一部に直線部分を含む被処理水の循環水路を構成する反応タンクの内部に曝気撹拌システムを設置する方法であって、
前記曝気撹拌システムは、垂直軸を中心として回転可能なインペラと、前記インペラを、一部を除いて囲むように配置された整流板と、を有し、前記整流板は、前記反応タンクを流れる循環水流の前記直線部分における前記インペラの上流側に向かって凸状の整流板湾曲部と、前記整流板湾曲部の両端から循環水流の前記直線部分における前記インペラの下流側に直線的に延びる１対の整流板直線部とを有し、
前記循環水路の前記直線部分において、前記インペラが、前記上流側において前記整流板湾曲部に覆われ、前記下流側においては１対の前記整流板直線部の間で開放され、かつ前記インペラの回転中心が、前記循環水路の幅方向において、前記中央区画壁の主面から、前記循環水路の全幅の１／３～２／３の距離だけ離れた位置に配置されるように、前記インペラと前記整流板とを配置する、曝気撹拌システムの設置方法。 A method of installing an aeration agitation system inside a reaction tank in which a peripheral wall and a central partition wall located inside the peripheral wall form a circulating channel for the water to be treated, at least a portion of which is a straight line, comprising:
The aeration agitation system has an impeller rotatable about a vertical axis , and a rectifying plate arranged to surround the impeller except for a part thereof, and the rectifying plate causes the flow to flow through the reaction tank. a straightening plate curved portion projecting toward the upstream side of the impeller in the straight portion of the circulating water flow; and a pair of rectifying plate straight portions,
In the linear portion of the circulating water passage, the impeller is covered with the straightening plate curved portion on the upstream side, and is open between the pair of straightening plate straight portions on the downstream side, and the impeller rotates. The impeller and said A method for installing an aeration stirring system, in which a rectifying plate is arranged. 前記インペラの回転中心から前記整流板直線部の先端までの、前記循環水路の前記直線部分の延びる方向における長さが、前記インペラの最大外径の１～３倍である、請求項９に記載の曝気撹拌システムの設置方法。 10. The method according to claim 9, wherein the length in the direction in which the linear portion of the circulating water passage extends from the center of rotation of the impeller to the tip of the linear portion of the current plate is 1 to 3 times the maximum outer diameter of the impeller. installation method of the aeration stirring system. １対の前記整流板直線部のうち少なくとも前記中央区画壁側に位置する前記整流板直線部が、前記整流板湾曲部との接続部から前記整流板直線部の先端に向かうにつれて前記中央区画壁側から前記周囲壁側に向かうように、該整流板直線部を３０度以下の角度だけ傾けて配置する、請求項９または１０に記載の曝気撹拌システムの設置方法。 Of the pair of straightening plate straight portions, at least the straightening plate straight portion located on the side of the central partition wall gradually expands toward the tip of the straightening plate straight portion from the connecting portion with the straightening plate curved portion. 11. The method of installing an aeration stirring system according to claim 9 or 10, wherein the linear portion of the rectifying plate is inclined by an angle of 30 degrees or less so as to face the peripheral wall side from the side.
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