JPH0128868Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention involves suspending solid particles as carriers for microbial attachment in a tank, and stirring the solid particles in the tank while stirring the gas using an air lift tube installed in the tank. This invention relates to a biological treatment device for wastewater that circulates and flows.

Recently, various biofilm-type sewage treatment systems have been put into practical use that have solved the bulking phenomenon and complexity of maintenance and management that occur in the activated sludge method, using tube catalytic oxidation method, rotating disk method, granular solid fluidized bed method, etc. ing. Among these, microorganisms are attached to the surface of solid particles suspended in the tank, and the solid particles in the tank are circulated and brought into contact with wastewater while stirring the gas through an air lift pipe installed in the tank. Compared to other biofilm methods, the granular solid fluidized bed method, which removes pollutants from wastewater, has a much larger surface area for solid particles to which microorganisms can attach, making it possible to retain a large amount of microorganisms in the tank. It is attracting attention because it has many advantages, including the fact that solid particles circulate and flow within the tank, so problems such as clogging and partial anaerobic formation do not occur.

In this type of granular solid fluidized bed method, the microorganism adhesion carrier is made of sand, anthracite, activated carbon, zeolite, plastic balls, etc., which are suitable for the adhesion of microorganisms, and have specific gravity and particles suitable for smooth circulation and fluidity in the tank. Solid particles with a certain diameter are used, but sand is usually used in consideration of cost and difficulty in obtaining it.

The fluidized bed biological treatment apparatus using the granular solid fluidized bed method has, as shown in FIG.
An air introduction pipe 4 is opened at the bottom of the air lift pipe 3 installed in the air lift pipe 3, and raw water is introduced from the raw water introduction pipe 6 by the air lift action accompanying the rise of air bubbles 5 blown into the air lift pipe 3. The solid particles 2 are circulating and flowing inside and outside the air lift pipe 3 together with the raw water.

In addition, a part or the entire circumference of the upper part of the tank 1 includes a partition wall 7 whose upper end is above the water surface and whose lower end is below the water surface and is separated from the tank wall.
A circulating section 8 for solid particles 2 including an air lift tube 3 and a separating section 9 for solid particles 2 are formed, and a part of the suspension in the tank 1 is separated through the lower end of the partition wall 7. During the ascent through section 9, the solid particles 2 are separated and removed from an upper outlet section 10 via a treated water outlet pipe 11.

In this conventional fluidized bed equipment, the treated water that flows out is sent to a coagulation sedimentation, sand filtration equipment, etc. as a post-treatment equipment, and the SS, BOD, and COD in the outflow water are
After undergoing treatment such as removal, it becomes final treated water.

By the way, in the conventional fluidized bed biological treatment apparatus using the air lift method, a part of the bubbles 5 discharged from the air lift pipe 3 is transferred by the downward flow of the circulation section 8, and this is transferred to the separation section 8 and the circulation section 9. passes through the lower end of the partition wall 7 that partitions the water and flows into the separation section 9 together with the outflow water, so some of the solid particles 2 in the circulation section 8 are carried away by the air bubbles 5 to the separation section 9, and some of the solid particles 2 are carried away into the separation section 9 in the outflow water. This often results in problems such as a decrease in performance due to a decrease in the amount of solid particles in the tank and blockage of the after-treatment equipment for runoff water. This outflow of solid particles 2 is particularly important when microorganisms
This phenomenon becomes more likely to occur as the specific gravity becomes lighter, and the higher the load of pollutants on the device and therefore the larger the amount of air blown, the higher the downward flow velocity in the circulation section 8. Since the amount of entrained air bubbles also increases, the amount of solid particles flowing out also increases. In the conventional device, as an improvement measure for this, the lower end of the partition wall 7 is bent toward the separation part 9 side to prevent air bubbles from getting mixed in, and the upper end of the air lift tube 3 is submerged deeper to prevent the discharge liquid from the air lift tube. Attempts have been made to reduce the amount of air bubbles 5 that are ejected onto the water surface and entrained as they fall, but this has not been sufficient, and it is inevitably necessary to install separation and collection equipment for outflowing particles at the rear of the device, resulting in unstable operation. In addition, they were forced to adopt an uneconomical equipment configuration.

The present invention eliminates the drawbacks of these conventional devices and provides a stable fluidized bed biological treatment device that does not cause outflow of solid particles, and specifically, provides a structure that prevents air bubbles from leaking into the separation section. The purpose is to

This invention has a raw water inlet and a treated water outlet, and contains solid particles for adhesion of microorganisms in a tank.
A circulation section and a separation section are defined by a partition wall whose upper end is above the water surface and whose lower end is separated from the tank bottom, and in the circulation section there is an air introduction pipe whose upper end is below the water surface and whose lower end is spaced from the tank bottom, and near the lower end. The fluidized bed biological treatment equipment is equipped with an airlift pipe connected to a gas bubble, and a bubble separation wall having an upper end near the water surface and a lower end below the water surface is disposed in the circulation section to prevent air bubbles between the air lift pipe and the partition wall. A separating section is formed into sections, and a baffle plate for collecting air bubbles is disposed in the separating section, one end of which is connected to the partition wall, and the other end of which is spaced apart from the tank wall, and the air bubble separating baffle plate is provided on the partition wall below the baffle plate. It is characterized by having an opening that communicates with the section.

An embodiment of the present invention will be described with reference to the drawings. In the second illustrated example, solid particles 2 for attaching microorganisms are suspended in a tank 1 having a raw water inlet pipe 6 and a treated water outlet pipe 11. Inside the floor biological treatment tank, a circulation section 8 and a separation section 9 are defined by a partition wall 7 whose upper end is above the water surface and whose lower end is below the water surface. Located below the water surface, the lower end is separated from the bottom of the tank, and the air inlet pipe 4 is located near the lower end.
An air lift pipe 3 connected to the air lift pipe 3 is provided.
In addition, the inner circulation part 8 of the partition wall 7 includes a bubble separation wall 1 whose upper end is almost near the water surface and whose lower end is below the water surface.
2 is disposed, and a bubble separating section 13 is disposed between the partition wall 7 and the partition wall 7.
is formed into sections, and this bubble separation section 13
A baffle plate 14 for collecting air bubbles is disposed inside the chamber, one end of which is connected to the partition wall 7, and the other end of which is isolated from the tank wall.
An opening 15 communicating with the bubble separating section 13 is formed in the partition wall 7 below the baffle plate 14. Although there may be one baffle plate 14 for air bubble collection, in the second illustrated example, there are a plurality of baffle plates 14 for air bubble collection, and in that case, both ends of the lower baffle plate 14' are separated from the partition wall 7 and the tank wall. Only the uppermost baffle plate 14 is connected to the partition wall 7, and the partition wall 7 below the baffle plate 14 is connected to the partition wall 7.
A case is shown in which an opening 15 communicating with the bubble separating section 13 is provided.

However, to explain its function, the raw water introduction pipe 6
The raw water that has flowed into the tank 1 is mixed with the circulating liquid containing the microorganism-adhered solid particles 2 circulating in the air lift pipe 3 and the circulation section 8 due to the air lift action of the air blown into the air lift pipe 3. During the circulating flow inside the raw water, the action of microorganisms attached to the solid particles 2 removes pollutants (BOD, COD, etc.) from the raw water.
ammonia, etc.) are decomposed and removed. A part of the liquid in the tank passes through the lower end of the partition wall 7 and flows into the separating section 9, where the solid particles 2 are separated and flows out from the upper outlet section 10 through the treated water outlet pipe 11. Air bubbles 5 that are carried along with the downward flow of the circulation section 8 and flow into the separation section 9
Most of the air bubbles 5 that have flowed into the vicinity of the partition wall 7 rise as they are, are captured by the baffle plate 14, and are returned to the bubble separation section 13 through the opening 15, but the air bubbles that have flowed in farther from the partition wall 7 are Once captured by the baffle plate 14', it slides up the lower surface of the baffle plate 14' and exits from one end, is captured by the baffle plate 14, and is returned to the bubble separating section 13 through the opening 15. In order to bring about the above effect, the baffle plate 14,1
4' is arranged at an angle, and the number of baffle plates is
One sheet or any plurality of sheets may be used, and when the amount of air or the amount of water to be processed is small, the amount of air bubbles 5 mixed into the separating section 9 is small, so one sheet is sufficient. If there are many baffles, it is desirable to install a plurality of baffle plates, connect only the uppermost baffle plate 14 to the partition wall 7, and provide an opening 15 in the partition wall 7 below it. In addition, when installing multiple baffle plates, arrange them so that one end overlaps under the baffle plate immediately above, as shown in the figure, so that the air bubbles form a path passing between each baffle plate as described above. Of course. Note that the opening 15 can be formed at any pitch below the baffle plate 14.

As described above, according to the present invention, it is possible to prevent air bubbles from flowing into the separation section in a granular solid fluidized bed biological treatment equipment that circulates and flows solid particles through an air lift effect, thereby eliminating the fatal drawback of solid particles flowing out. , it is possible to carry out fluidized bed biological treatment stably and economically.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a conventional device, and FIG. 2 is a sectional view showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Tank, 2... Solid particles, 3... Air lift pipe, 4... Air introduction pipe, 5... Bubbles, 6... Raw water introduction pipe, 7... Partition wall, 8... Circulation section, 9... Separation part, 10... Outflow part, 11... Treated water outflow pipe, 1
2...Bubble separation wall, 13...Bubble separation part, 14,
14'... Air bubble collection baffle plate, 15... Opening.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. In a tank that has a raw water inlet and a treated water outlet and contains solid particles for adhesion of microorganisms, the water is circulated through a partition whose upper end is above the water surface and whose lower end is separated from the bottom of the tank. The fluidized bed biological treatment apparatus is provided with an airlift pipe having an upper end below the water surface, a lower end spaced apart from the tank bottom, and an air introduction pipe connected near the lower end, in the circulation part. A bubble separation wall having an upper end substantially near the water surface and a lower end below the water surface is disposed in the circulation part to form a bubble separation part between the partition wall, and one end of the bubble separation wall is disposed in the separation part. A bubble collecting baffle plate connected to the tank wall and having the other end spaced apart from the tank wall is provided, and an opening communicating with the bubble separating part is bored in the partition wall at the lower part of the baffle plate. Floor biological treatment equipment. 2 A plurality of the air bubble collecting baffle plates are arranged above and below, one end of the uppermost baffle plate is connected to the partition wall, and an opening communicating with the air bubble separating section is bored in the partition wall below the baffle plate. A fluidized bed biological treatment apparatus according to claim 1 of the utility model registration claim.