JPS6257362B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a superconcentration device, and in particular to a superconcentration device for sludge that can efficiently increase the degree of concentration by changing stepwise the difference between the pressure on the sludge side to be treated and the pressure on the liquid discharge side. Concerning a superconcentrator.

In general, sludge discharged from water treatment plants and sewage treatment plants is composed of 97-99% water and the remaining 1-3% solid matter, which is particulate sludge, which reduces the overall sludge treatment cost. In order to reduce this, there is a strong demand for so-called sludge concentration and volume reduction, which increases the proportion of solids in primary sludge. As a method, a centrifuge or gravity sedimentation concentrator may be used, or a filtration device consisting of a sieve with a sieve surrounded by a cloth mesh and a liquid discharge pipe connected to the sieve may be installed in a sludge tank. Various methods are used, such as a superconcentrator that is suspended in a tank and is designed to pull out superconcentrated sludge from the bottom of the tank. However, when using a centrifugal separator as a method to increase concentration, in addition to the increased electricity cost to increase the centrifugal force, there is also noise and
There are problems with vibration and sagging. In the case of gravity sedimentation and thickening equipment, there are no major problems in terms of energy and environmental impact, but because the separation and concentration depends on the weight of the sludge particles, the tank volume can be expanded or the water depth deepened to prevent sludge from stagnation in the tank. It is possible to increase the time, but in either case, the degree of concentration is low considering the investment amount, and there is a problem with economic efficiency. In the case of the above-mentioned superconcentration device, it is necessary to apply suction force to the cloth screen using a vacuum pump or the like, which reduces the energy saving effect.

The present invention was invented in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a superconcentrator that can efficiently concentrate and reduce volume without reducing the energy saving effect of the above-mentioned superconcentrator.

In order to achieve the above object, the superconcentrator according to the present invention includes a supertank into which primary sludge containing a large amount of water is charged, a supertank suspended in the supertank,
A sieve plate having a sieve chamber surrounded therein by a cloth mesh, a first liquid pipe connected to the sieve chamber of the sieve plate, a first liquid pipe branching out from the first liquid pipe in stages, and a branching stage. A plurality of liquid pipes whose lengths are lengthened according to the length of each liquid pipe, a drain valve that is built into the pipe of each liquid pipe and can be opened and closed independently, and a drain valve that is arranged at the outlet end of each of the liquid pipes, It is characterized by being equipped with a liquid tank designed to maintain the surface position.

Embodiments of the superconcentrator according to the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 indicates a tank, and this tank 1 is surrounded by a front plate 2, a back plate 3, and a pair of side plates 4, 5, with the lower portions of the side plates 4, 5 facing inward. It is bent into a dogleg shape and tapers downward, and the terminal ends of the front plate 2, rear plate 3, and pair of side plates 4, 5 are closed by a bottom plate 7. The upper part of the tank 1 has an opening 8, and the above-water sludge is passed through the opening 8 into the tank 1.
It can be loaded inside. Above tank 1
A cake discharge pipe 10 is connected to the bottom plate 7 of the machine, and a cake discharge valve 11 is installed on the pipe, and a cake discharge pump is installed at the end of this pipe, although not shown. There is.

In the overtank 1, four overboards 12, 12, 12, 12 are suspended with intervals between them. As shown in FIG. 2, each overboard 12 has cloth nets 14 and 15 placed on both sides of a picture frame-shaped spacer frame 13, and tightening frames 16 and 17 are brought into contact with them from the outside and fixed with screws. An over-chamber 18 is formed between the cloth nets 14 and 15.

Therefore, from the central upper part of each of the four overplates 12, liquid extraction pipes 19, 19, 19, 19 are connected.
A first liquid pipe 21 is led out from the center of the liquid collection pipe 20, and this first liquid pipe 21 extends vertically downward, and its lower end is connected to a liquid collection pipe 20. It is immersed in the liquid in the tank 22. The first liquid tank 22 includes an overflow tank 24 outside the overflow edge 23, and the level of the liquid in the first liquid tank 22 is always maintained at a constant level. In the illustrated example, the siphon height from this liquid level to the center of the liquid collection pipe 20 is H ₁ [m].

Further, from the middle of the first liquid pipe 21, a second
The liquid pipe 25 and the third liquid pipe 26 are branched out, and the second liquid pipe 25 extends downward to the second liquid pipe 26.
It is submerged in the liquid in the liquid tank 27, and the third liquid pipe 26 extends downward and submerged in the liquid in the third liquid tank 28. The second liquid tank 27 is provided with an overflow tank 29 on one side to keep the liquid level of the second liquid tank 27 constant, and from the liquid level to the center of the liquid collection pipe 20. The siphon height of H ₂
[m] On the other hand, the third liquid tank 28 has an overflow tank 30 on one side to keep the liquid level in the third liquid tank 28 constant, and to collect the liquid from the liquid level in the tank. The siphon height to the center of the water pipe 20 is H ₃ [m]
The above-mentioned siphon heights H ₁ , H ₂ ,
There is a relationship between H ₃ as H ₁ < H ₂ < H ₃ .

On the pipes of the first, second and third liquid pipes 21, 25 and 26, there are a first drain valve 31, a second drain valve 32 and a third drain valve 33 which can be opened and closed individually. Each is included.

On the other hand, from the middle of the first liquid pipe 21, the suction pipe 3
4 is branched out, a suction valve 35 is disposed on the pipe, and a vacuum pump 36 is installed at the end of the pipe.

An air vent pipe 37 is led upward from a part of the liquid collection pipe 20, and an air vent valve 38 is provided on the pipe.

Further, a compressed air supply pipe 40 is connected to the first liquid pipe 21 near the connection part to the liquid collection pipe 20, and at the end of this pipe there is a compressed air supply source (not shown), and there is a compressed air supply source on the pipe. When the supply valve 41 of the screen is opened, compressed air is blown into the screen 12 so that the cake attached to the screen can be peeled off.

Next, the operation of the above-mentioned superconcentrator will be explained.

Prior to operation, all valves are fully closed, and primary clean water sludge is charged into the overtank 1 from above the opening 8 of the overtank 1. Next, the suction valve 35 is opened, the vacuum pump 36 is driven, the pressure in the overchamber 18 in the overboard 12 is set to a negative pressure corresponding to the siphon height H ₁ [m], the vacuum pump 36 is stopped, and suction is performed. Keep valve 35 closed. Then, the sludge particles of the primary clean water sludge in the filter tank 1 settle due to their own weight, and the water is removed by the cloth net 1.
4 and 15 into the chamber 18. Therefore, as a first step, only the first drain valve 31 is opened. The liquid in the chamber 18 is then drained into the first liquid tank 22 through the first liquid pipe 21 under a low vacuum pressure corresponding to the siphon head _H1 . At this stage, no strong suction force is applied to the cloth nets 14, 15, and a cake layer is formed on the cloth nets 14, 15 over time without clogging.

Next, after a certain period of time has elapsed, the first drain valve 31 is closed and the second drain valve 32 is opened. Then,
The degree of vacuum in the overchamber 18 changes to an intermediate vacuum pressure corresponding to the head _H2 , and overwork continues. At this stage, the cake layer acts as a material, and even if the vacuum pressure increases, thickened sludge can be produced without causing problems such as clogging of the material.

Further, after a certain elapsed time has elapsed, the second drain valve 32 is closed and the third drain valve 33 is opened at the same time. Then, the degree of vacuum in the overchamber 18 changes to a high vacuum pressure corresponding to the siphon head _H3 , and overwork continues.

In Fig. 3, the horizontal axis shows elapsed time, and the vertical axis shows the vacuum pressure inside the overflow chamber. This shows that the vacuum pressure can be increased step by step by opening.

When the siphon height _H3 reaches its limit, the first drain valve 31, second drain valve 32 and third drain valve 33 are closed, and the supply valve 41 is opened to supply compressed air to the first liquid. Blow through the pipe 21 into the passage chamber 18,
The adhering cake on the overplates 12, 12, 12, 12 is peeled off and settled in the form of lumps. After peeling, open the valve on the sludge return pipe installed in the middle of the side plate of the overtank 1 to return the diluted sludge in the upper layer of the tank to the original tank, then open the cake discharge pipe 10 and discharge it. One concentration process is completed by driving a pump (not shown) and drawing out the thickened sludge.

As is clear from the above explanation, according to the present invention, by increasing the pressure difference between the inside and outside of the cloth net in stages, it is possible to dramatically increase the amount of liquid discharged, resulting in a high It can give a concentrated effect. Combined with the effect that suspended sludge particles in the tank separate and settle due to their own weight during one superconcentration process, the degree of concentration of primary sludge can be significantly increased without reducing the original energy saving effect. be.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of the superconcentration device according to the present invention, Fig. 2 is a perspective view showing the overboard, and Fig. 3 is a diagram showing the state of the stepwise overconcentration mode. . 1... over tank, 12... over board, 14, 15...
...Cloth net, 19...Liquid extraction pipe, 21...First
Liquid pipe, 22...first liquid tank, 25...second liquid pipe, 26...third liquid pipe, 27...second liquid tank,
28...Third liquid tank.

Claims (1)

[Scope of Claims] 1. A filtration tank into which sludge containing a large amount of water is charged, and a filtration system suspended within the filtration tank, with a filtration chamber surrounded by a filter cloth net. a first filtrate pipe connected to a filtration chamber of the filtration board; and a plurality of filtrate pipes that are branched out from the first filtrate pipe in stages and whose lengths are lengthened according to the branching stage. , comprising a drain valve that is incorporated on the pipe line of each filtrate pipe and can be operated to open and close independently, and a filtrate tank that is arranged at the outlet end of each of the filtrate pipes and maintains the respective liquid level. A filtration and concentration device characterized by: 2. In the filtration/concentration device according to claim 1, the filtration disk is composed of a plurality of sheets, and a filtrate extraction pipe is led out from the upper center of each filtration disk, and these are connected to the filtrate collection pipe to connect to the first filter. A filtration and concentration device characterized in that it is connected to a filtrate pipe.