JPS6018240B2 - Fluidized bed wastewater treatment tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluidized bed wastewater treatment tank, and its purpose is to fluidize particles with wastewater to adsorb and remove dissolved substances in the wastewater, or to remove substances dissolved on the surface of particles. In an expanded bed wastewater treatment tank that biologically treats organic matter in wastewater by forming a chemical film, it eliminates the stagnation part of the flowing particles inside the treatment tank, prevents clogging of the tank, and stabilizes the operation. The objective is to increase the capacity of the processing tank, simplify the tank structure, make maintenance and inspection easier, and reduce the manufacturing cost of the device.

In particular, the fluidized bed treatment tank according to the present invention is an upflow type adsorption tank that adsorbs and removes dissolved substances in wastewater using activated carbon, and oxidizes ammonia nitrogen with aerobic bacteria, converting it into nitrite or nitrate nitrogen. As a nitrification tank, these nitrite or nitrate nitrogens are reduced in the presence of anaerobic bacteria,
It is particularly effective as a denitrification tank for separating nitrogen gas or as a granular bed type activated sludge treatment tank for treating wastewater by forming an activated sludge film on the particle surface.

In addition, it is also useful as a particle-filled wastewater treatment device using an up-and-down flow system, such as an ion exchange resin adsorption tank and an up-flow rapid filtration tank. Thus, the method of the present invention is an improved method of providing an expanded bed of packed particles for use in water treatment. Conventionally, an expanded bed using particles as a filler has been used in activated carbon adsorption tanks, ion-exchange resin adsorption tanks, chelate resin adsorption tanks, nitrification tanks, denitrification tanks, particle-based sludge tanks, and the like.

However, in order to create an inflatable layer in good condition, it is necessary to take great care to provide a sufficient rectifying support layer. For example on a perforated plate or perforated block (400/skin) diameter 20
It is generally done to pile up crushed stones, gravel, sand, etc. with diameters of 1 to 1/2 in the order of increasing the size of the particles upwards, until the total height is around 400/m. There is. Although a rectifying layer is indispensable for the expansion layer as described above, the provision of a rectifying layer has major drawbacks. 1st
The expansion bed itself is a downward flow fixed bed.Although the gap between the packed particles is wide and there is less clogging in the flow, the rectifying bed is a fixed bed, and small particles are Because it is filled, blockage occurs due to SS and the generation of microorganisms. For this reason, a clarification transition must be carried out as a pretreatment. Nevertheless, the risk of blockage cannot be avoided. Once blockage occurs, the expansion layer collapses and a short-circuit flow occurs, reducing treatment efficiency and eventually rendering the system inoperable. Second, although the expansion layer has a feature of low pressure loss, the rectifying layer causes a considerable increase in the erosion loss. Thirdly, the cost of the straightening bed is very high, including the need for a pretreatment process, which causes the equipment cost of the expansion bed type treatment tank to be high. The method of the present invention provides an expanded bed type fluidized bed that solves these drawbacks all at once.

The treatment tank of the present invention is a wastewater treatment tank in which wastewater is treated by a fluidized bed of microorganisms attached to solid particulate adsorbents or solid particle carriers, and the wastewater treatment tank is made of a pyramid or cone with a top surface of 600 to 1200, or a bottom surface. The tangent at the point of contact between the plane and the outer periphery at 1/2 of the height of the part is 45o~7 from the vertical
It has a bottom surface made of a curved surface with an angle of 5o, and is located below 1/2 of the height of the bottom part and at the center of the rice cake, and the water to be treated is directed to the slope or curved surface of the bottom surface so that it is almost horizontal. This is a fluidized bed type wastewater treatment tank characterized by being equipped with a to-be-treated water inlet pipe that blows out to-be-treated water. The water to be treated that comes out from the entrance of the inlet pipe spreads radially centering on the horizontal direction while entraining particles, and then collides with the slope or curved surface of the bottom and turns vertically, flowing along the inner surface and flowing to the bottom of the treatment tank. to form a jet. The treated water introduced into the treatment tank forms a jet at the bottom of the tank, while a portion of it rises to the top of the tank, forming an expanded layer of solid particles in this part. The spout area at the bottom of the tank functions in place of the support layer for fixed rectification in the conventional fluidized bed system. The average liquid flow rate in the pot needs to be sufficient to fluidize the filled particles.

The fluidization start speed is given as a function of particle diameter, liquid density, particle true specific gravity, minimum porosity, particle shape coefficient, etc., and it is clear that a liquid flow rate higher than this must be provided. Another important thing is the blowing speed at the tip of the blowing nozzle.

This blowing speed is such that the blown water reaches the surrounding area of the rice cake,
All particles at the bottom of the rice cake must be suspended. This optimal blowing speed is influenced by particle diameter, particle true specific gravity, particle formation coefficient liquid density, nozzle position, etc., but is generally 1 skin/sec or more, preferably 3 h/sec.
The above blowing speed is suitable. In a fluidized bed, the average flow rate in the cellar is determined by the particles used, so the cell diameter is determined according to the liquid flow rate.

Therefore, the blowing speed can be changed by selecting the nozzle diameter. In order to obtain a good expanded layer at the same liquid flow rate, it is necessary to provide a sufficient blowing velocity. If the blowing velocity is not large enough for the diameter of the grain, an upward flow will be generated only near the nozzle, and extreme drift will occur in the area that should become the expanded layer, causing particles in the peripheral area to become completely stagnant. Eventually, an anaerobic block is formed and floated to the surface through anaerobic fermentation. On the other hand, if the blowing speed is too large relative to the diameter of the grain, the jet flow becomes large, the expansion layer becomes relatively small, and the particles are more likely to wear out, which is undesirable, and there is a certain suitable speed range. do. Therefore, the blowing speed must be set in close relation to the flow rate. Next, the shape of the bottom is a cone, a pyramid, or a hemisphere, and the shape of a hemisphere to ensure stable circulation of the liquid and particles in the jet area. It is selected so as to give an inclination that can be dispersed in the vertical direction.

If the apex angle is 4 mm higher than 600, the liquid flow will be concentrated in the center, and the movement of particles will be extremely slow in the periphery of the tower.
This tends to cause retention angle, making it difficult to create a uniform expanded layer throughout the tower, and causing the generation of anaerobic areas. On the other hand, if the apex angle is larger than 120 degrees, the liquid flow will not reach around the bottom, making it impossible to form a uniform expansion layer.

For the same reason, in the case of a bottom made of a curved surface, the tangent at the point of contact between the plane passing through the center of the bottom and the curved surface should be within the range of 45o to 75o from the vertical.

The outlet of the water introduction pipe to be treated must be located below 1/2 of the height of the bottom surface. If the position of the inlet and outlet is higher than this, drift will occur, making it impossible to form a good expanded layer of packed particles, resulting in a decrease in processing efficiency.
It is preferable that the air outlet is located at the bottom of the bottom as much as possible, and most preferably the bottom is shaped like a cone, pyramid, or curved surface with the tip cut horizontally, and the air outlet is provided close to the bottom. It is. The present invention will be specifically explained using an example in which a cone having a diameter of 1m and having a cone having an apex angle of 600 mm as a base is used.

Bead carbon with a diameter of 0.4 to 0.8 and a rib specific gravity of 1.9 was used as the packing particles, the column diameter was lm, and the depth of the curved surface was 0.
5. With a katana with a bottom of 500mm, the tip of the blowing nozzle should be 0.0 from the kabo bottom.
．． 1 Position on the skin, low in the slit/all around the skin 9
A nozzle with an outlet of 0 m/m blew out the air at a rate of 0.26/min in the horizontal direction over the entire circumference.

The space-time column velocity was about 20 m/hr, the blowing velocity from the nozzle was about 5 k/sec, and the bed expansion coefficient was 1.8.
A good fluidized bed with a head pressure loss of 400 to 50 mAg per unit height of ~2.3 layers can be obtained. When using this fluidized bed as a denitrification tank for nitrate nitrogen, if the depth of the cell is 4, the flow time of the liquid will be about 12 minutes, which can provide the necessary and sufficient conditions for denitrification. Approximately 350 can be used as a waste with a throughput capacity of 350 g/day. This tank can be used as a fluidized bed activated carbon adsorption tank under almost the same conditions.

In addition, by the same method as in the above example, packed particles with a diameter of 0.
Anthracite with 5 to 0.8 ribs and true specific gravity of 1.4 is placed in a tank with a diameter of 1
．． When fluidizing with an 8m sieve, water flow rate is 125〆/Hr.
When the blowing speed is 6 m/sec and the superficial velocity is 50 skin/Hr, a good fluidized tank with a bed expansion coefficient of 1.6 to 2.2 and a head pressure loss per bed unit height of 200 to 25 Ag is obtained. can get. This rice cake is good as a nitric tank for ammonia nitrogen. Next, the apparatus of the present invention will be explained in more detail with reference to the drawings. Figures 1 and 2 show a single tank with a four-sided pyramid and a conical bottom, respectively, and wastewater is introduced from a conduit 3.
It is blown out from the blowing nozzle 4 toward the side surface of the tank bottom 1 and discharged from the discharge nozzle 2.

The introduction pipe may be attached from the top of the pot or may be introduced from the bottom, and must have an outlet for blowing out the water to be treated in a substantially horizontal direction toward the slope or curved surface of the bottom. The end of the inlet pipe is closed, and the water to be treated is blown out from a pipe opening that closes upward or downward, or where the side wall of the inlet pipe has many holes or slits near the end. A fluidized bed type wastewater treatment tank of the present invention can be effectively used in the fluidized bed type wastewater treatment tank of the present invention, which is equipped with a collision plate on the opposing surface so that it can be deflected. In addition, when the diameter of the rice cake becomes large, it is preferable to use a shape in which an inlet pipe is opened on one side of plates facing each other at a distance, as shown in Fig. 3. Tapering the blowing part has the effect of smoothing the liquid flow and preventing backflow of particles when stopped. As described above, the fluidized bed type wastewater treatment apparatus of the present invention has no part where particles stagnate, and as a result, no clogging occurs in the tank, and stable operation can be performed.

The tank structure is also simplified in terms of operation and maintenance.

[Brief explanation of drawings]

1 and 2 are perspective views of the treatment tank of the present invention, and FIG. 3 shows an example of the outlet of the water conduit to be treated. 1...bottom of tank, 2...discharge port, 3...
...Water introduction pipe to be treated. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A wastewater treatment tank for treating wastewater with a fluidized bed of fine particles attached to a solid particulate adsorbent or a solid particulate carrier,
The wastewater treatment tank is made of a pyramid or cone with a top surface of 60° to 120°, or a curved surface such that the tangent at the point of contact between the plane and the outer periphery at 1/2 the height of the bottom part is 45° to 75° from the vertical. The height of the bottom surface is 1/1 of the height of the bottom surface.
Fluidized bed type wastewater, characterized by comprising a treated water inlet pipe located below 2 and at the center of the tank, which directs the treated water to the slope or curved surface of the bottom and blows out the treated water almost horizontally. Processing tank. 2. The fluidized bed wastewater treatment tank according to claim 1, comprising a water introduction pipe having a closed end and a large number of holes or slits in the side wall of the pipe near the end. 3. The fluidized bed type wastewater treatment tank according to claim 1, comprising a water introduction pipe to be treated, which comprises an opening opening upwardly or downwardly and a collision plate provided opposite the opening.