JPH0534798Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to the improvement of an aeration tank used for treating organic wastewater in sewage treatment plants and the like.

(Conventional technology) To treat organic wastewater, wastewater is placed in an aeration tank, activated sludge is added thereto, and air is blown into the tank using an aeration device to create a swirling flow in the tank and agitate the tank. The activated sludge method, in which the activity of aerobic microorganisms in activated sludge is increased by oxygen in the air to perform biological treatment of organic matter, is most commonly adopted. For this purpose, conventionally, as shown in FIGS. 3 and 4, the tank body 11 is divided into two parts by a vertical buttful plate 3, and an air diffuser 12 is installed in the middle position of one side of the tank body at a water depth of 4 to 5 m. Aerated tanks are used. Inside such an aeration tank, a swirling flow in the direction of the arrow is formed due to the buoyancy of the bubbles generated from the aeration device 12, but since the water flow is centered near the wall of the tank body 1, the flow velocity is low. When the distribution was measured, the result was as shown in FIG. 3, for example, and it was found that even a flow in the opposite direction occurred in a portion near the center baffle plate 13, and a uniform swirling flow was not formed. Furthermore, as a result, when measuring the distribution of DO (dissolved oxygen) concentration, as shown in Figure 4, the DO value is low in the area near the center of the tank, which is a dead zone where oxygen is insufficient and biological treatment cannot be performed effectively. It was also found that

(Problems that the invention attempts to solve) This invention solves the conventional problems as mentioned above,
By creating a swirling flow that is as uniform as possible throughout the entire area of the tank, the formation of oxygen-deficient areas is prevented, and as a result, biological treatment by aerobic microorganisms is activated throughout the entire area of the tank. It was completed with the purpose of creating an aeration tank for this purpose.

(Means for solving the problem) The present invention is to divide the tank body into two by a vertical buttful plate, provide an air diffuser on one side, and place the air diffuser in the center on the opposite side of the aerator with the buttfull plate in between. It is characterized by having an inclined guide plate, which deflects the horizontal flow downward, installed at a position slightly below the nearby water surface, independent of the baffle plate.

(Embodiments) Next, the present invention will be described in detail with reference to illustrated embodiments.

In Figures 1 and 2, 1 is, for example, a depth
The tank body of a deep aeration tank is 10 m long, 10 m wide, and several tens of meters long in the paper direction.
The air diffuser 3, which was installed at a middle position at around 5 m, is a baffle plate that is vertically installed in the center of the tank 1 and divides the inside of the tank 1 into two. Reference numeral 4 designates an inclined guide plate that is fixed independently of the full board 3 at a position slightly below the water surface near the center on the opposite side of the full board 3 from the side where the air diffuser 2 is installed. . This inclined guide plate 4 is for deflecting downward the flow that has passed horizontally through the upper part of the bubble plate 2 out of the swirling flow formed by the buoyancy of bubbles generated from the air diffuser 2. In the example, the distance between the upper end of the vertical board 3 and the water surface is 2 m, and the inclined guide plate 4 is installed at an angle of 45° so that its upper end is located 1 m below the water surface and its lower end is located 2 m below the water surface. Fixed. Incidentally, the inclined guide plate 4 may have a gently curved cross-sectional shape like a turbine blade, or a plurality of inclined guide plates 4 may be attached at appropriate intervals. Furthermore, more preferable results can be obtained by bending the upper inclined portion 5 of the tank body 1 as shown by imaginary lines in FIG. 1, or by providing a similar inclined guide plate 6 above the air diffuser 2. be able to.

(Function) In this structure, after the tank body 1 is filled with waste water, compressed air is ejected into the water as a large number of bubbles from the air diffuser 2 located in the middle of one side of the full plate 3, and the buoyancy of the air is used to Therefore, the conventional method is to generate a swirling flow in the tank as shown in the figure to stir the wastewater in the tank and at the same time supply oxygen, thereby treating organic wastewater using the activated sludge method. It is similar to However, in the present invention, an inclined guide is provided at a position slightly below the water surface near the center of the tank body 1 on the side opposite to the side where the air diffuser 2 is provided, with the buttful plate 3 interposed therebetween. Board 4
, the water flow directly below the water surface that flows horizontally over the upper part of the buttful plate 3 in the center of the tank flows along the wall surface of the tank body 1 as before, but the lower part flows horizontally. The water flow flowing through the tank is deflected downward by the area guide plate 4, and a swirling flow is also formed in the area close to the baffle plate 3 in the tank. As a result, the flow velocity distribution in the aeration tank of the present invention is as shown in Figure 1, for example. Comparing this with Figure 3, which shows the flow velocity distribution in the conventional aeration tank, the variation in flow velocity is extremely small, and the overall It can be seen that a uniform swirling flow was formed over the area.

As a result, it becomes difficult to form a dead zone with a low flow rate inside the aeration tank of the present invention, so the DO concentration distribution becomes as shown in Figure 2. It is clear that a nearly uniform DO concentration can be obtained over the entire area.

(Effects of the invention) As is clear from the above explanation, the present invention provides an inclined guide plate in the central part on the opposite side of the air diffuser across the double plate inside the tank, which is divided into two by the double plate. A swirling flow is also generated in the center of the tank, which equalizes the flow velocity distribution and DO concentration distribution within the tank, allowing aerobic microorganisms to actively perform biological treatment throughout the tank. It was a success. Therefore, according to the present invention, the entire area inside the tank can be used effectively, so if the tank is the same size, the processing capacity can be improved, and if the processing capacity is constant, the tank size can be reduced. can be converted into Therefore, the present invention will greatly contribute to the development of industry as an aeration tank that eliminates the problems of the conventional system.

[Brief explanation of the drawing]

Figure 1 is a vector diagram showing the flow velocity distribution in the aeration tank according to the embodiment of the present invention, Figure 2 is a DO concentration distribution diagram, and Figure 3 is a vector diagram showing the flow velocity distribution in the conventional aeration tank. , FIG. 4 is a distribution map of the DO concentration. 1...tank body, 2...aeration device, 3...buttful board, 4...inclined guide plate.

Claims (1)

[Scope of utility model registration request] The tank body 1 is divided into two parts by a vertical butt-full plate 3, and the air diffuser 2 is installed on one side of the tank body, and the air diffuser 2 is installed at a position slightly below the water surface near the center on the opposite side of the air diffuser 2 across the butt-full plate 3. An aeration tank characterized in that an inclined guide plate 4 for deflecting a horizontal flow downward is provided independently of a buttful plate 3.