JPS6216686B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a suspension clarification processing apparatus that uses a granular floating material as a material and is equipped with a backwash mechanism. An example of a conventional device of this type is the device disclosed in Japanese Patent Application Laid-Open No. 51-60675, shown in FIG. That is, in this device, the upper part is supplied to the upper part B by means of the stock solution supply means 52 provided in the central part of the tank body.
and a tank body 51 whose lower part is a coagulation sedimentation part A, having a liquid discharge means 70 at the upper end of the upper part,
A cylinder is provided with a layer 60 made of granular floating material on the upper part of the upper part, and has both upper and lower end surfaces open entirely in the upper part at a position below the layer position during suspension clarification processing operation and above the stock solution supply means 52. shaped body 62
An air supply pipe 65 having an upward spout is installed inside the cylindrical body 62, and the water level inside the tank is lowered during backwashing operation to cause the cylindrical body 62 to flow inside the layer.
Means 67 and 68 are provided for positioning the layer 60 so that the upper end thereof is located, and the floc forming means 57 is disposed at a position in contact with or close to the supply port of the stock solution supply means 52 in the coagulation and precipitation section A. It is characterized by having a slurry discharge means 59 at the lower end of A. In this device, during backwashing operation, the water level in the tank is lowered, the layer is lowered, and the upper end of the cylindrical body is positioned inside the layer, and then air is jetted from an upward spout onto the material inside the cylindrical body. ,
The material is cleaned by spreading the entire material in a fluid manner due to the air lift effect. By the way, when a flotation material is used for a long period of time and the material is washed repeatedly, the surface of the material particles becomes dirty and suspended substances tend to adhere to it gradually. When a large amount of suspended matter adheres to the material in this way, its weight increases, and eventually material particles that settle from the floating material layer appear. This phenomenon occurs more easily as the specific gravity of the floating material approaches 1, and in the case of general suspended solids generated during wastewater treatment,
For example, if a floating material with a specific gravity of 0.7 is used for two to three months, 30 to 60% of the material will settle and be consumed. Moreover, when the settled material is discharged together with the slurry, it may cause failure of the mud removal valve or pump. In order to prevent the sedimentation and consumption of the floating material as described above, it is sufficient to use a material with a low specific gravity. However, when the specific gravity of the floating material becomes small, the backwashing mechanism using the air flow in the conventional device described above has a problem with the flow of the material. Development does not occur satisfactorily, making cleaning of the material difficult.
The same can be said of the overflow device disclosed in Japanese Patent Publication No. 53-26861, which employs a reverse mechanism similar to the conventional device. The present invention has been improved so that cleaning can be carried out satisfactorily even when using a granular flotation material with a small specific gravity, and instead of the air supply pipe 62 in the conventional device, This purpose can be achieved by, for example, providing a propeller-type stirring blade in the cylinder and stirring and pumping the liquid inside the cylindrical body through its operation. That is, the present invention includes a cylindrical body with both upper and lower ends open, the upper end of which is located inside a layer of granular floatation material during a backwash operation, and a suspension that blows out an upward airflow inside the cylindrical body. The present invention relates to a turbid liquid clarification processing apparatus, characterized in that a means for stirring and pumping the liquid inside the cylindrical body is provided in place of the above-mentioned upward air jetting means. Next, a specific example of the present invention will be described with reference to FIG. The inside of the tank body 1 is divided into a coagulation and sedimentation section A below the center and a sedimentation section B above the center.
The coagulation sedimentation part A or the lower part thereof is the slurry accumulation part C.
It is subdivided into The tank body 1 may be of either a closed type or an open type, and may have an appropriate cross-sectional shape such as a circular shape or a polygonal shape. A stock solution supply pipe 2 is arranged in the center of the tank body 1 that separates the coagulation and sedimentation part A and the sedimentation part B, and is connected to a pump 4 through a valve 3, and has a valve 5 in the middle. A pipe 6 for supplying auxiliary agents such as the like is connected. A floc forming means 7 is connected to the supply port of the stock solution supply pipe 2 into the tank body 1. The raw solution flows into the flocculation means 7 in a tangential direction, is stirred by an internal obstacle (not shown), and is then given a uniform downward flow and discharged to the coagulation and sedimentation section A. be done. Although a rod-shaped obstacle was used as the obstacle in this example, it is only necessary to mix the liquid to be treated and the auxiliary agent in this area, and all of the conventionally known baffle plates, inclined plates, etc. can be used. . In the part that partitions the tank body 1 around the floc forming means 7, there is an overflow prevention plate (for example, a radial direction from the outer periphery of the floc forming means 7 toward the inside of the tank body 1) to prevent sludge from flying up during backwashing. A plurality of plate bodies 8 having a predetermined width are arranged. A slurry discharge pipe 10 having a valve 9 is connected to the bottom of the tank body 1, which is the lower end of the coagulation and sedimentation section A. In this device, the height of the coagulation-sedimentation section A minus the slurry accumulation section C, that is, the distance from the lower end of the floc forming means 7 to the upper end of the inverted conical section in the figure, must be equal to or greater than the diameter of the tank body 1. is desirable. In addition, as shown in the figure, the tank body 1 in the slurry accumulation section C is given a certain angle from its upper end to its lower end, so as to facilitate the collection and pressurization of solids that settle to the bottom of the tank. The angle of inclination is generally 60 degrees with respect to the horizontal plane. However, this angle may be changed as appropriate depending on the quality of the sludge. A layer 11 made of a granular floating material (for example, polyethylene) having a specific gravity lower than that of the stock solution and a supporting plate 12 having a gap large enough to prevent the floating material from flowing out are provided at the upper part of the filter part B. The cylindrical body 13 is arranged in the upper part B at a position below the position of the layer 11 (i.e., the position indicated by the solid line in the figure) during the suspension clarification operation and above the stock solution supply pipe 2. . This cylindrical body 13 may be circular or square as long as its upper and lower end surfaces are open, and the number of cylindrical bodies 13 may be one or more. The cross-sectional area of the cylindrical body 13 is 1/10 to 1/2 of the cross-sectional area of the tank body.
Its height is preferably 1.2 to 2 times the thickness of layer 11. The vertical arrangement position of the cylindrical body 13 within the upper part B may be appropriately selected within the above-mentioned limitations, but in the case of an apparatus having a structure as shown in the figure, it is preferable to set the cylindrical body 13 at a distance from the floc forming means 7. It is desirable that the floc forming means 7 be located above the floc forming means 7 so that the material flowing downward from the cylindrical body 13 during backwashing does not touch the floc forming means 7. A stirrer 14 having propeller-type stirring blades is provided inside the cylindrical body 13. By its operation, the stirrer 14 stirs the liquid within the cylindrical body 13 and pumps up the liquid, and supplies the pumped liquid to the outside of the cylindrical body 13 .
The present apparatus having such a cylindrical body 13 and stirring/pumping means 14 is further provided with means for lowering the layer 11 during backwashing so that the end of the cylindrical body 13 is located inside the layer 11. in particular,
A drain pipe 16 having a valve 5 in the center of the tank body 1
and its wallet-on breaker 17 are provided. According to this means, as the water level in the tank body 1 decreases, the layer 11 also descends until it reaches the position indicated by the chain line in the figure and is stopped. At this time, it is desirable that the upper end of the cylindrical body 13 be located inside the layer 11 within a range of 0 to 20 cm. At the upper end of the tank body 1, which is the upper end of the overflow part B, there is an overflow port 18 for liquid.
and a tube 19 are provided. Also, valve 2
0 is connected to the backwash water supply pipe 21,
The pipe 21 is also connected to the drain pipe 16 by a bypass pipe 23 having a valve 22. 24 is a rotational drive source for the stirrer 14. To operate this device, first, only the valve 3 is opened, and the pump 4 supplies the stock solution. During the supply of the stock solution to the tank body 1 through the pipe 2, a necessary amount of auxiliary agent such as a polymer flocculant is supplied through the pipe 6 to form a mixed stock solution. This mixed stock solution flows through the tube 2 into the floc forming means 7 located in the center of the tank body 1. The mixed stock solution flowing into the floc forming means 7 is accelerated to coagulate by the swirling flow caused by the tangential flow and the stirring effect by the obstacles, as described above. At this time, the flocs become coarse, are given a downward flow together with the liquid, and are discharged from the floc formation means 7 to the coagulation and sedimentation section A. Suspended substances in the discharged liquid are accumulated in the slurry accumulation section C by gravitational sedimentation, and the liquid is clarified. The accumulated slurry is sequentially discharged from the pipe 10. In this way, most of the suspended solids are removed from the liquid, but the liquid that remains with suspended solids that do not settle rises and reaches the layer 11 formed of the floating material. Suspended substances remaining in the layer 11 are sufficiently trapped and the liquid is clarified. The clarified liquid is taken out from the overflow port 18 through a pipe 19, and is reused or discharged depending on the purpose. After continuing the above operation, if excessive trapping of suspended solids by the layer 11 progresses and a differential pressure (for example, 1.0 to 1.5 Kg/cm ² ) indicating a blockage state of the layer 11 is generated, backwash the layer 11 of the device. Implement. First, the supply of the stock solution is stopped and the valve 3 is closed. Next, the valve 15 is opened to lower the water level in the tank body 1 and lower the layer 11. When the layer 11 falls to the position indicated by the chain line in the figure, air flows in from the siphon breaker 17, stopping the water level from decreasing and the layer 11 from falling, and causing the flow of the layer 11 to flow above the layer 11 during backwashing. Create the necessary space. Next, the stirrer 14 is rotated by the drive source 24. Stirrer 1
4, the material particles of the layer 11 located inside the cylindrical body 13 are separated into individual particles.
This is diffused and spreads over the entire layer 11, and finally, the material particles flow together with the liquid in the tank body 1 through the inside and outside of the cylindrical body 13 as shown in the figure, and intense flow development of the layer 11 occurs. Due to the shearing force and impact force caused by the collision between the materials at this time, the slag that adhered to the materials is separated satisfactorily, and the slag that has adhered to the materials joins, aggregates, and becomes coarse.
It accumulates on the bottom of the tank as a precipitate. Meanwhile, valve 2
0 is opened and backwash water is supplied from the upper end of the tank body 1.
After carrying out the backwashing operation for an appropriate time (about 5 to 10 minutes), the operation of the agitator 14 is stopped and the operation is continued for an appropriate time (about 10 minutes).
(about 1 minute). Next, valves 15 and 20 are closed, valve 3 is opened, and pump 4 is operated to supply the stock solution. Due to the rise in the liquid level in tank body 1, layer 1
1 reaches the support plate 12 and is fixed and stabilized. Since the effluent contains suspended matter, the valve 22 is opened and the effluent is returned to the stock solution tank (not shown). Thereafter, when the layer 11 is stabilized and a clear liquid is obtained, the valve 22 is closed and the above-mentioned clarification operation is started. In order to compare the device of the present invention with the above configuration with the conventional device, we adopted a layer with a height of 60 cm and a diameter of 100 cm, and performed treatment using a stock solution with an SS concentration of 50 ppm. etc., the first
As shown in the table. Therefore, according to the device of the present invention, it is possible to more vigorously flow the material during backwashing operation, and even when using materials with small specific gravity, the backwashing efficiency is excellent. It is clear that the fining time is extended and the wastage of the material is reduced. Furthermore, since the device of the present invention is characterized by the backwashing mechanism of the layer as described above,
The scope of the present invention also includes devices equipped with a backwashing mechanism, such as the filtering device disclosed in Japanese Patent No. 26861, which is intended only for filtering undiluted solutions. 【table】

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a conventional device, and FIG. 2 is a schematic diagram showing an example of the device of the present invention, in which 1 is a tank body, A is a coagulation sedimentation part, B is a part,
C is a slurry accumulation part, 2 is a stock solution supply pipe, 7 is a flocculation means, 10 is a slurry discharge pipe, 11 is a layer, 13 is a cylindrical body, 14 is a stirring and pumping means, 16
17 is a siphon breaker, 18 is a liquid overflow port, and 21 is a backwash water supply pipe.

Claims (1)

[Claims] 1. A cylindrical body with both upper and lower ends open, the upper end of which is located inside a layer of granular floatation material during backwashing operation, and an upward air flow is ejected inside the cylindrical body. 1. A suspension clarification treatment apparatus, characterized in that, in place of the above-mentioned means for ejecting upward airflow, means for stirring and pumping the liquid within the cylindrical body is provided. 2. The device according to item 1 above, wherein the granular floating material has a specific gravity of 0.1 to 0.8. 3. The device according to item 1 or 2 above, wherein the stirring and pumping means is a stirrer equipped with propeller-type stirring blades.