JP6124829B2 - Biological water treatment apparatus and biological water treatment method - Google Patents

Description

  The present invention relates to a biological water treatment apparatus provided with a vertical axis type aeration stirring apparatus, and a biological water treatment method in which surface aeration stirring is performed by a vertical axis type aeration stirring apparatus.

As a method for biologically treating water to be treated such as sewage or sewage, a method using an oxidation ditch tank in which an endless circulation channel is formed is known. As the aeration and agitation apparatus in this oxidation ditch tank, three types of a vertical axis type, a horizontal axis type and an oblique axis type are known.
The vertical axis aeration and agitation device rotates the impeller with a part of the impeller on the surface of the water to be treated to perform surface aeration, and forms an agitation flow in the oxidation ditch tank to create microorganisms. To improve the growth environment.

  Patent Document 1 describes an invention in which a vertical aeration agitator is provided in a straight water channel of an oxidation ditch tank. This will be described with reference to FIG. 7. In the conventional oxidation ditch tank 1 shown in FIG. 7, the straight water channel A and the circulation water channel B are formed by the peripheral wall 2 and the partition wall 3, and the partition wall 3 of the straight water channel A is formed. A vertical axis aeration and stirring device 4 and a baffle 5 are provided adjacent to.

In the vertical axis type aeration and agitation device 4, the impeller rotates counterclockwise in a plan view and splashes water to be treated on the surface to be treated. The water to be treated can sufficiently take in air by splashing as water droplets.
The baffle 5 is an arc-shaped plate member that is installed in water in a state where a part thereof is placed on the surface of the water to be treated, and adjusts the flow of the water to be treated. Details of the flow of water to be treated will be described later.

  In addition, the horizontal axis aeration and stirring apparatus will be described with reference to FIG. A shaft is bridged between the peripheral wall 2 and the partition wall 3, and stirring blades provided at predetermined intervals on the shaft rotate to aeration and agitate the water to be treated.

JP 2013-22509 A

  Here, the vertical axis aeration apparatus is generally superior in aeration performance and maintainability compared to the horizontal axis / oblique axis aeration apparatus. There is a need to replace it with a shaft type aeration stirrer. Then, when replacing the existing horizontal axis type aeration and stirring apparatus with the vertical axis type aeration and stirring apparatus, there is a problem that it is desired to minimize the change of the existing part.

Therefore, in order to replace the vertical axis aeration stirrer with the attachment port of the horizontal axis type aeration agitator, the vertical axis aeration agitator is fixed to a frame that covers the mounting port. There was a new problem that the environment inside the foundation ditch tank could not be confirmed.
Therefore, when the inspection port was provided in the gantry, the further problem that the splash splashed by the impeller collided with the adjacent partition wall 3 and bounced off, re-scattered upward, and jumped out from the inspection port. Further, when a transparent window is provided at the inspection port 45, there arises a problem that the window becomes dirty due to splashes.

As a result of intensive studies on the above problems, the present inventor has found that the splashing portion can be prevented from jumping out from the inspection port by projecting the splashing portion on the wall surface adjacent to the impeller.
Specifically, the present invention provides the following biological water treatment apparatus and biological water treatment method.

(First invention of the present application)
The configuration of the first invention of the present application for solving the above problems includes a frame having an inspection port, a shaft suspended from the frame, and a vertical axis aeration and agitation device having an impeller provided around the shaft. A biological water treatment apparatus comprising: a splash returning portion provided on a wall surface adjacent to the impeller and preventing splash from splashing to the inspection port.
(The second invention of the present application)
The structure of the second invention of the present application for solving the above problem is the biological water treatment apparatus according to the first invention of the present application, wherein the wall surface is a partition wall surface or a surrounding wall surface.
(The third invention of the present application)
In the configuration of the third invention of the present application for solving the above problem, the length (X) from the wall surface to the tip of the splashing portion is less than the length (X1) from the wall surface to the shaft peripheral surface. The biological water treatment apparatus according to the first invention or the second invention of the present application, characterized in that.
(The fourth invention of the present application)
According to a fourth aspect of the present invention for solving the above-described problem, the length (Y) of the width of the splashed portion is equal to or greater than the length of the radius of the outermost circumference of the impeller, and the outermost circumference of the impeller. The biological water treatment apparatus according to any one of claims 1 to 3, wherein the biological water treatment apparatus has a length equal to or less than twice the diameter.
(The fifth invention of the present application)
The configuration of the fifth invention of the present application for solving the above-mentioned problems is a process of introducing treated water into a biological water treatment apparatus, a gantry having an inspection port, a shaft suspended from the gantry, and A step of subjecting the water to be treated to surface aeration and stirring by means of a vertical axis aeration and stirring device having an impeller provided around the shaft; splashes of water to be treated generated by the surface aeration and stirring are provided on a wall surface adjacent to the impeller. And a step of preventing the splashed portion from splashing to the inspection port.

According to the biological water treatment device of the first invention of the present application, since splash of the water to be treated can be prevented from splashing to the inspection port by the splash-back portion, the rotation state of the vertical aeration agitator from the inspection port and It becomes possible to check the operation state such as the flow state of the water to be treated.
Moreover, even when the transparent window provided at the inspection port is provided, it is possible to prevent the transparent window from being soiled by splashes.

  According to the biological water treatment apparatus of the second invention of the present application, the vertical aeration agitator can be installed in the straight water channel, so that a good aeration process can be performed.

  According to the biological water treatment apparatus of the third and fourth inventions of the present application, the effects of the present invention can be further enhanced.

  According to the biological water treatment method of the fifth invention of the present application, the operation state such as the rotation state of the vertical aeration agitator, the flow state of the water to be treated and the state of surface aeration agitation is checked, and if there is an operation abnormality. It can be discovered early and stable biological water treatment becomes possible.

It is a schematic explanatory drawing which shows the structure of the oxidation ditch tank to which the biological water treatment apparatus of the 1st Example of this invention is applied. It is an expanded sectional view which shows the structure of the vertical axis | shaft type aeration stirring apparatus and splash part of 1st Example of this invention. It is a supplementary figure for demonstrating the magnitude | size of the splash return part of 1st Example of this invention. It is a supplementary figure for demonstrating the installation area | region of the splash return part of 1st Example of this invention. It is a supplementary figure for demonstrating the installation area | region of the splash return part of 1st Example of this invention. It is an expanded sectional view which shows the structure of the vertical axis | shaft type aeration stirring apparatus and droplet return part of 2nd Example of this invention. It is a schematic explanatory drawing which shows the structure of the biological water treatment apparatus provided with the conventional vertical axis | shaft type aeration stirring apparatus. It is a schematic explanatory drawing which shows the structure of the biological water treatment apparatus provided with the conventional horizontal axis type aeration stirring apparatus.

  In the following examples, an oxidation ditch tank to which the biological water treatment apparatus and the biological water treatment method of the present invention are applied and the water treatment method thereof will be described.

FIG. 1 is a schematic explanatory view showing the configuration of an oxidation ditch tank to which the biological water treatment apparatus according to the first embodiment of the present invention is applied.
The oxidation ditch tank 1 includes an elliptical peripheral wall 2 and a partition wall 3 installed in a straight line at the center of the peripheral wall 2 in the same manner as the conventional one illustrated in FIG. Forming. This circulating water channel is divided into a straight water channel A formed by straight portions of the partition wall 3 and the peripheral wall 2 and a circulating water channel B formed by an arc-shaped portion of the peripheral wall 2.

Further, in the oxidation ditch tank 1, a vertical aeration agitator 4 and an arc-shaped baffle 5 are installed in the straight water channel A so as to be adjacent to the partition wall 3, and splash back above the water surface of the partition wall 3. Part 7 is provided.
The vertical axis aeration and agitation device 4 is installed with a part of the upper part of the impeller protruding on the surface of the water to be treated. Details of the configuration of the vertical axis aeration and stirring device 4 will be described later.
The baffle 5 is disposed on the upstream side of the vertical axis type aeration and agitation device 4, and a plurality of legs extending downward or laterally are fixed to the bottom of the oxidation ditch tank 1 or the partition wall 3 by a fixture such as a bolt. . Most of the baffles 5 are immersed in the water to be treated, and the baffles 5 are installed with their upper ends slightly above the surface of the water to be treated.
The splash returning part 7 is installed at a position adjacent to the vertical axis type aeration and stirring device 4 so as to protrude from the partition wall 3.

The oxidation ditch tank 1 is charged with sewage and activated sludge as water to be treated, and forms a counterclockwise circulation flow C1 in plan view as shown in FIG. The impeller of the vertical axis aeration and stirring device 4 installed in the straight water channel A rotates counterclockwise in plan view, forms a stirring flow C2 around the impeller, and is deposited on the bottom of the oxidation ditch tank 1 Promotes dispersion of solids.
At this time, the agitation flow C2 of the water to be treated formed by the vertical axis type aeration and agitation device 4 forms a flow in the direction opposite to the circulation flow C1 in the vicinity of the partition wall 3. The baffle plate 5 rectifies the stirring flow C2 in the flow direction of the circulating flow C1 so that the circulating flow C1 is not disturbed by the flow in the reverse direction.

  Moreover, the vertical axis | shaft aeration stirring apparatus 4 scatters to-be-processed water as a splash on a water surface. The splashes of the water to be treated sufficiently take in air while splashing around the vertical axis aeration and agitation device 4. This makes the water to be treated aerobic and promotes the action of microorganisms. The splashes scattered in the downstream direction and the peripheral wall 2 direction land on the water to be treated, and the splashes scattered in the upstream direction land on the baffle 5 (broken arrows in the figure). On the other hand, the splash splashed in the direction of the partition wall 3 collides with the partition wall 3 and resprays upward.

Next, the vertical axis type aeration and stirring device 4 will be described in detail. FIG. 2 is an enlarged cross-sectional view showing the configuration of the vertical axis aeration and agitation device 4 and the splashing part of the first embodiment of the present invention.
The vertical axis aeration and agitation device 4 includes a gantry 41, a shaft 42, an impeller 43, and a drive unit 44. The shaft 42 passes through the gantry 41, and the upper end is connected to the drive unit 44 at the upper part of the gantry 41. On the other hand, the lower end of the shaft 42 hangs down into the oxidation ditch tank 1 and has an impeller 43.
The drive unit 44 applies a rotational force to the shaft 42 to rotate the impeller 43.
The gantry 41 is fixed to the partition wall 3 and the ceiling 6 of the oxidation ditch tank 1. The gantry 41 may be fixed to the peripheral wall 2 in addition to the partition wall 3 and the ceiling portion 6.
Further, the vertical axis aeration and stirring device 4 may be provided at any location of the oxidation ditch tank 1. For example, it may be installed adjacent to the peripheral wall 2 of the straight flow path A or may be installed adjacent to the partition wall 3 of the circulation flow path B.

  Furthermore, the inspection port 45 is provided in the mount frame 41 of the vertical axis | shaft type aeration stirring apparatus 4 of this invention. The inspection port 45 is an opening for visually recognizing the situation inside the oxidation ditch tank 1. The inspection port 45 may be provided with a transparent plate material such as glass or an acrylic plate as a window. An open / close lid may be provided.

In addition, the splashing portion 7 is installed on the partition wall 3 adjacent to the impeller 43. The splash returning part 7 is for preventing the splash (broken line arrow in the figure) that collides with the partition wall 3 and resprayed upwards from splashing into the inspection port 45.
The shape of the splash returning part 7 may be any shape as long as the splash is prevented from scattering in the upper direction, and examples thereof include rectangular, trapezoidal, and semicircular plate materials.
Although the material is not specifically limited, metal materials, such as stainless steel, and plastic materials, such as an acrylic board, are mentioned. Moreover, the mesh material which can restrict | limit the passage of splashes may be used.

  The splashing part 7 is installed in such a way that it protrudes with respect to the partition wall 3 at a predetermined angle θ. In the first embodiment shown in FIG. 2, the partition wall 3 is attached so as to protrude in the vertical direction (θ = about 90 °). A preferable angle θ is 45 to 135 °, and particularly preferably 45 to 90 °. It is preferable to set the angle θ to 90 ° or less so that the droplets colliding with the splashing part 7 are likely to fall toward the water to be treated. However, when the angle θ is less than 45 °, the splashes are prevented from scattering upward. The area where it can be narrowed. Moreover, if it exceeds 135 degrees, the splash prevention effect to the upper direction of a droplet will become low.

The splash returning part 7 may be provided on any wall surface according to the installation position of the impeller 43. For example, when the vertical aeration agitating device 4 is installed in the vicinity of the surrounding wall 2, the splash returning part 7 can be provided on the surrounding wall 2.
Further, the splash returning part 7 may be provided on any wall surface as long as the splash collides and resprays upward, for example, a baffle or other rectifying wall, or a backflow prevention plate for preventing the splash backflow. Etc. are exposed on the surface of the water, and the splashing portion 7 may be provided on a member such as a baffle or a backflow prevention plate as long as the splash collides with these members and resprays upward.

FIG. 3 is a supplementary diagram for explaining the optimum size of the splash returning part 7. The length (X) from the partition wall 3 to the tip of the splashing part 7 is preferably less than the length (X1) from the partition wall 3 to the peripheral surface of the shaft 42.
Furthermore, the length (X) is preferably equal to or longer than the length (X0) from the partition wall 3 to the outermost circumference of the impeller. As shown in FIG. 3, the impeller outermost circumference circle is the outermost circumference circular orbit among the circular orbits formed by the members constituting the impeller 43 when the impeller 43 is rotated.
By making the length (X) of the splash returning part 7 equal to or greater than the length (X0) and less than the length (X1), re-scattering of the splash in the upper direction can be completely stopped.
Here, when supplementing the lengths (X), (X0), and (X1) when the shape of the splash returning part 7 is not rectangular, these lengths pass through the center point of the shaft 42 (42c in FIG. 5). Measured along the perpendicular of the partition wall 3

  The length (X) may be 100 to 500 mm. If it is 100 mm or more, re-scattering of the splash in the upper direction can be sufficiently suppressed, and if it is 500 mm or less, the field of view from the inspection port 45 is widened, which is preferable.

On the other hand, the length (Y) of the width of the splash returning part 7 is preferably not less than the length of the radius of the outermost circumference circle of the impeller and not more than twice the diameter of the outermost circumference circle of the impeller. . By setting it as this range, the re-scattering of the splash to the upper direction can fully be suppressed.
Here, if it supplements about the length (Y) of the said width | variety in case the splash return part 7 is not a rectangle, the length (Y) of the said width is the part which contacts the wall surface at the time of planar view of the splash return part 7 Means the width of

  4 and 5 are supplementary diagrams for explaining an appropriate installation range of the splash returning unit 7. The installation position of the splash returning part 7 is not particularly limited as long as it is a position that prevents re-scattering of the splash in the upper direction, but it is installed in a range that blocks the flight route of the splash toward the inspection port 45. It is preferable.

FIG. 4 shows an appropriate installation range in the height direction of the splash returning part 7. The splash returning part 7 is installed between the upper end 43t of the impeller outermost circumference circle and the gantry lower end 41b. Assuming that the height from the upper end 43t to the gantry lower end 41b is Z0, the splash return lower end 7b is preferably installed in the range of 0.1 to 0.8Z0 from the upper end 43t, more preferably It is in the range of 3 to 0.6Z0. Within this range, the effects of the present invention are fully exhibited.
In addition, if it supplements about the case where the splash return part 7 is not horizontal, the splash return part lower end 7b uses the lower end of the front-end | tip part in the center of the width length (Y) of the splash return part 7, and the installation range of a height direction To decide.

FIG. 5 shows an appropriate installation range in the lateral direction of the splash returning part 7. The splash returning part 7 is preferably installed in a range (Y0) corresponding to the length of the diameter of the outermost circumference of the impeller in the left-right direction from the shaft center point 42c. By installing in this range, the effect of the present invention is sufficiently exhibited.
To supplement the case where the splash returning part 7 is not rectangular, it is preferable that the right and left ends of the splash returning part 7 be installed so as not to come out of the range Y0 in plan view.

FIG. 6 is an enlarged cross-sectional view showing the configurations of the vertical axis aeration and agitation device 4 and the splashing part of the second embodiment of the present invention.
In the second embodiment, the bearing opening 31 formed for the bearing of the shaft of the horizontal axis aeration and agitation device is closed when the conventional horizontal axis aeration and agitation device is replaced with the vertical axis aeration and agitation device 4. It is an oxidation ditch tank 1 provided with a guide plate 32 to perform.

When the horizontal axis type agitating apparatus is replaced with the vertical axis type agitating apparatus, bearings for receiving the shaft of the horizontal axis type agitating apparatus remain on the peripheral wall 2 and the partition wall 3 as cavities. Since the straight water channel A is temporarily expanded by this cavity, there is a problem that the flow velocity of the circulating flow C1 is reduced. Therefore, in the second embodiment of the present invention, a guide plate 32 for closing the bearing opening 31 is provided.
The shape of the guide plate 32 may be any shape as long as the width of the straight water channel A is constant, and is usually a plate-like member.
The material is not particularly limited, and examples thereof include a metal material such as stainless steel and a plastic material such as an acrylic plate. Stainless steel is preferable from the viewpoint of corrosion resistance and strength.

Further, the upper portion of the guide plate 32 is folded back toward the inside of the oxidation ditch tank to constitute the splashing portion 7.
In addition, you may comprise the guide plate 32 and the splash return part 7 as a separate member. For example, the guide plate 32 may be a flat plate member, and the splash returning portion 7 may be attached to the upper portion of the guide plate 32. What is necessary is just to comprise the splash return part 7 as an attachment member similarly to the 1st Example.

The biological water treatment method of the present invention includes a step of introducing treated water into a biological water treatment apparatus, a frame having an inspection port, a shaft suspended from the frame, and a periphery of the shaft. A step of aeration and agitation of the water to be treated by a vertical axis aeration and agitation device having an impeller provided; a splash of water to be treated generated by the surface aeration and agitation is provided on a wall surface adjacent to the impeller; And a step of preventing the portion from scattering to the inspection port.
To-be-treated water is obtained by adding microorganisms such as activated sludge to water containing organic components such as organic sludge such as sewage sludge and organic wastewater such as sewage.

  The biological water treatment apparatus and the biological water treatment method of the present invention are not only used in the oxidation ditch tank of the embodiment, but also a cylindrical tank type aeration tank or a plurality of tanks connected together in one direction. It can also be used in biological treatment equipment that treats sewage.

In addition, the biological water treatment apparatus and biological water treatment method of the present invention should be used in an aerobic microorganism treatment tank for organic sludge in a sewage treatment plant or the like, and organic waste water in a food factory or a pharmaceutical factory. Can do.
Furthermore, it can also be used for microbial culture tanks in experimental facilities and pharmaceutical production.

  DESCRIPTION OF SYMBOLS 1 Oxidation ditch tank, 2 Perimeter wall, 3 Compartment wall, 31 Bearing opening part, 32 Guide plate, 4 Vertical axis | shaft type aeration stirring apparatus, 40 Horizontal axis type aeration stirring apparatus, 41 mount frame, 41b mount frame lower end, 42 shaft, 42c Shaft center point, 43 impeller, 43t Impeller outermost circle upper end, 44 drive part, 45 inspection port, 5 baffle, 6 ceiling part, 7 splashing part, 7b splashing part lower end, A straight water channel, B circulation channel, C1 circulation Flow, C2 stirring flow

Claims (5)

An oxidation ditch tank that forms a circulation channel;
A gantry having an inspection port, a shaft suspended from the gantry, and a vertical axis aeration and stirring device having an impeller provided around the shaft,
On the wall surface of the oxidation ditch tank, provided apart from the pedestal, and a splash returning part for preventing the splash from splashing to the inspection port;
A biological water treatment apparatus comprising:   The biological water treatment apparatus according to claim 1, wherein the wall surface is a partition wall surface or a surrounding wall surface. The length (X) from the wall surface to the tip of the splash return part is not less than the length (X0) from the wall surface to the outermost circumference of the impeller, and the length from the wall surface to the shaft peripheral surface ( The biological water treatment apparatus according to claim 1 or 2, wherein the biological water treatment apparatus is less than X1).   The length (Y) of the width of the splashed portion is not less than the length of the radius of the outermost circumference circle of the impeller and not more than twice the diameter of the outermost circumference circle of the impeller. The biological water treatment apparatus according to claim 1, wherein A process of introducing treated water into an oxidation ditch tank that forms a circulation channel ,
A step of subjecting the water to be treated to aeration by a vertical axis aeration and agitation device having a frame having an inspection port, a shaft suspended from the frame, and an impeller provided around the shaft;
A step of preventing splashes of water to be treated generated by the surface aeration and agitation from being splashed to the inspection port by a splash return portion provided on the wall surface of the oxidation ditch tank and separated from the gantry ,
A biological water treatment method comprising:

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