CN102159509A - Suction filtration/concentration method and suction filtration/concentration device - Google Patents

Abstract

The invention provides a suction filtration/concentration method which comprises a sludge supply stage in which sludge is supplied to a filtration/concentration tank, a filtration/concentration stage in which the supplied sludge is concentrated by filtration within the filtration/concentration tank, a thick-sludge separation stage in which the thick sludge obtained by the filtration/concentration is separated from the outer surface of the filter cloth, and a thick-sludge discharge stage in which the separated thick sludge is discharged outside the filtration/concentration tank, wherein the filtration/concentration stage involves a step in which the thick sludge is adhered to the outer surface of the filter cloth by continuously performing suction at a given suction pressure that enables the thick sludge to retain the shape thereof even when separated in unconcentrated sludge, and the thick-sludge separation stage involves a step in which water is continuously and forcedly sent to the filter cloth via the filtration chamber over a given period to thereby separate, in the supplied unconcentrated sludge, the thick sludge (filter cake) adherent to the outer surface of the filter cloth. A suction filtration/concentration device is provided.

Description

Suction filtration concentration method and suction filtration concentration device

technical field

The present invention relates to a suction filtration concentration method and a suction filtration concentration device, and more specifically, to a suction filtration concentration method and a suction filtration concentration device capable of efficiently discharging concentrated sludge to the outside without redissolving the sludge.

Background technique

Currently, a suction filtration thickening device using a siphon principle and a suction pump is used in a step of thickening sludge generated when upper water is filtered. Since the suction filtration concentration device has a bag-shaped filter cloth forming a filter chamber inside, the suctioned sludge (sludge before concentration) is separated into water and concentrated sludge. That is, the moisture contained in the sludge is guided into the filter chamber through a large number of pores of the filter cloth, and recovered as filtrate. In addition, the dehydrated and concentrated sludge adheres to the outer surface of the filter cloth, and then undergoes peeling treatment, and is discharged to the outside of the suction filtration concentration device (see Patent Document 1).

Moreover, in the prior art, when peeling the concentrated sludge adhering to the outer surface of such a filter cloth from a filter cloth, the process of following (S1)-(S4) was performed. First, the non-concentrated sludge in the filter concentration tank is discharged to the outside and temporarily stored (S1). This is in order not to reduce the degree of thickening of the thickened sludge by dissolving the thickened sludge into the non-thickened sludge. Then, air (gas) at a predetermined pressure is sent from the inside of the filter cloth to the outside through the filter chamber (S2). Concentrated sludge adheres to the entire outer surface of the filter cloth, clogging a large number of fine pores of the filter cloth. Therefore, by sending air, the filter cloth is expanded and deformed outward, and the concentrated sludge can be forcibly peeled outward by allowing the air to pass through a large number of pores. Then, the concentrated sludge is discharged to the outside (S3). The concentrated sludge peeled off by said (S2) accumulates in the bottom of a filtration thickening tank. Therefore, the thickened sludge must be removed from the filter thickener. Then, the stored unconcentrated sludge is returned to the filter thickening tank (S4).

As described above, according to the conventional suction filtration concentration device, the concentrated sludge is peeled off from the filter cloth by air in the atmosphere. Thereby, the concentrated sludge can be peeled off from a filter cloth, without reducing the concentration degree of sludge. Moreover, the air pressure is adjusted according to the degree of adhesion of the concentrated sludge to the filter cloth.

However, there are technical problems described below in the stripping technique of such concentrated sludge.

First, due to the compressibility of air as a medium for detachment, it is difficult to achieve desired detachment properties for concentrated sludge. For example, if concentrated sludge adheres to the entire outer surface of the filter cloth, many pores of the filter cloth will also be clogged with the concentrated sludge. Therefore, the shape retention of the thickened sludge adhering to the entire outer surface is insufficient, and if air is sent to the filter cloth in a state where the adhesion force between the filter cloth and the thickened sludge is not uniform, fine particles from a part of the filter cloth are easily The hole leaks air. In addition, if air leaks from a part of the pores of the filter cloth, the air will easily flow out from this part. That is, since air is difficult to flow out from other parts of the filter cloth, it is difficult to peel off the concentrated sludge adhering to other parts. Therefore, in the circumferential direction of the bag-shaped filter cloth, non-uniform peeling occurs, and concentrated sludge that cannot be peeled remains on the filter cloth. If the concentrated sludge remains on the filter cloth, other methods such as scraping off the remaining concentrated sludge by hand must be used to reduce the treatment efficiency of the concentrated sludge.

In addition, if the concentrated sludge is peeled off in the non-concentrated sludge without discharging the non-concentrated sludge from the filter thickening tank, the concentrated sludge will be redissolved, so that the concentrated sludge cannot be efficiently discharged to the outside. Therefore, as mentioned above, conventionally, the concentrated sludge was peeled from the filter cloth by air in the atmosphere. However, in such peeling treatment, when the concentrated sludge is peeled off from the filter cloth, a lot of noise is generated. Therefore, there is a problem that the installation place of a suction type sludge thickening apparatus is restricted. This is the 2nd question. In addition, the generation of the above-mentioned loud noise is caused by, for example, the ejection sound of air ejected from a large number of pores of the filter cloth when the air is pressure-fed from the inside of the filter cloth. In addition, the collision sound when the stripped thickened sludge falls to the bottom of the filtration thickening tank, etc. are also causes. That is, the collision sound is generated when the concentrated sludge falls in the atmosphere and collides with the bottom of the filter concentration tank in the sludge thickening tank for discharging unconcentrated sludge to the outside. Since the above-mentioned ejection sound and collision sound, which use the filter concentration tank as the sound source, reverberate in the filter concentration tank, it is easy to become additional noise.

Third, the concentrated sludge accumulated at the bottom of the filter concentration tank has no shape retention, and it is difficult to discharge the concentrated sludge to the outside. This is caused by the use of air in the atmosphere to strip the thickened sludge from the filter cloth. That is, the thickened sludge is peeled from the filter cloth by air, falls to the bottom of the filter thickening tank in the air with low resistance, and collides. The shape of the thickened sludge is deformed by this collision, and it accumulates at the bottom as a sediment without shape retention. Here, "shape retention" means to what extent the concentrated sludge adhering to the filter cloth maintains the plate-like form (size, thickness, etc.) at the time of adhering. For example, when the thickened sludge at the time of peeling is peeled off as a large block (a block whose longest part of the shape is 100 mm or more, preferably 150 mm or more), and its shape is hardly deformed in the subsequent steps , it can be judged that the shape retention is good. Conversely, it can be said that the shape retention property is poor when it becomes a small block at the time of peeling, or when the peeled block is decomposed into a small block, or is decomposed into an extremely small size.

In connection with the technical problem described above, Patent Document 2 discloses a method and an apparatus for concentrating sewage sludge. In the method and device described in Patent Document 2, a flat membrane module is arranged in a sludge thickening tank (equivalent to the above-mentioned filter thickening tank), and by intermittent suction by a suction pump, the upper surface of the sludge flowing into the sludge thickening tank is sucked. Water sludge is filtered and concentrated. More specifically, the moisture of the upper water sludge flowing into the sludge thickening tank passes through the pores of the flat membrane module and is collected as filtrate. On the other hand, the sewage sludge that cannot pass through the fine pores adheres to the outer surface of the flat membrane module, thereby forming concentrated sludge with a concentrated concentration of about 25%. Then, air or water is intermittently pressure-fed to the inside of the flat-membrane module by a blower. The concentrated sludge adhering to the outer surface of the flat membrane module is peeled off from the unconcentrated upper water sludge by the intermittently pressure-fed air or water. The stripped concentrated sludge settles in the unconcentrated upper water sludge and accumulates at the bottom of the sludge thickening tank. Then, the thickened sludge is captured by the thickened sludge separation filter installed at the bottom of the sludge thickening tank, and the unthickened sludge is discharged to the outside. As mentioned above, thickened sludge and non-thickened sludge are separated in the sludge thickening tank. Then, the upper water sludge accumulated in the bottom of the sludge thickening tank is discharged to the outside using a screw conveyor.

As mentioned above, Patent Document 2 discloses a stripping technique for stripping concentrated sludge using air or water in a liquid (upstream sludge), which can solve the above-mentioned first to third technical problems. However, in the filter concentration device of Patent Document 2, even if the agglomeration (block or layer) of the concentrated sludge attached to the outer surface of the flat membrane module becomes an agglomerate sheet (from the surface of the filter cloth or membrane in a larger Concentrated sludge peeled off in the shape of lumps), the concentrated sludge can be peeled off from the outer surface of the flat membrane module in the form of agglomerated sheets, but the agglomerated sheets of the peeled concentrated sludge are easily affected by the air bubbles ejected from the diffuser pipe. Affected by stirring (foaming), it becomes layered and easily broken.

That is, the device of Patent Document 2 is still at the technical stage of filtering and concentrating sludge using a flat membrane module using a suction pump. In other words, when the sludge is attached to the outer surface of the flat membrane module, the concentration of the sludge is as high as 20% or more. However, conversely, in order to facilitate the peeling of the concentrated sludge, the suction by the suction pump is performed "intermittently". Therefore, the sludge attached to the outer surface of the flat membrane module must be densified. That is, the agglomeration (agglomerate or layer) of the concentrated sludge adhering to the filter cloth in this state has shape retention to the extent that it will not redissolve before the peeling treatment, but it must easily become soft after peeling. And a small shape (small piece), or a state without a shape. In addition, according to Patent Document 2, in order to facilitate the peeling of the concentrated sludge, air or water is supplied "intermittently", and the filter membrane is repeatedly expanded and contracted. At the same time, aeration takes place on the outside of the flat-membrane module (ie, the above-mentioned "bubbling"). And, when the non-concentrated sludge is discharged, the non-concentrated sludge flows between the concentrated sludge of the agglomerated sheet. Therefore, the thickened sludge of soft and relatively small agglomerated pieces accumulated in the bottom of the sludge thickening tank after peeling is strongly affected by the above-mentioned influence, and the agglomerated pieces are broken into layers. Therefore, in the filtration concentration device of Patent Document 2, the agglomerated pieces are redissolved before the concentrated sludge is discharged, and the concentrated sludge cannot be efficiently taken out.

In addition, it is difficult to use the siphon type filter concentration device of Patent Document 1 to perform peeling treatment of concentrated sludge in non-concentrated sludge. This is because the concentrated sludge adhering to the outer surface of the filter cloth dissolves in the non-concentrated sludge when the concentrated sludge is peeled off in the non-concentrated sludge. In addition, in the state of agglomeration (the state of lumps or layers when sludge adheres to the filter cloth), the concentrated sludge cannot be peeled off. In addition, the concentrated sludge accumulated in the bottom of the sludge thickening tank cannot be discharged to the outside while maintaining its shape retention.

That is, the siphon filter concentrator disclosed in Patent Document 1 using a filter cloth as a filter system captures solids whose particle size is originally smaller than the pores of the filter cloth, unlike the case of using a filter membrane shown in Patent Document 2. Therefore, a film layer in which solid parts are condensed and densely formed is formed on the surface of the filter cloth, and solid parts smaller than the pores of the filter cloth are filtered (so-called dynamic filtration). In a siphon filter concentration device using a filter cloth, filtration is possible even if the suction force is not so strong, so solids do not accumulate on the surface of the membrane to impede filtration, and intermittent operation to remove the solids is not required (ie, interruption of the filter concentration operation due to backwashing). In addition, due to low-pressure suction, the concentrated concentration of the attached concentrated sludge is low, and the adhesion strength between the attached solid parts is weak. Therefore, in the absence of suction, the adhesion between solid parts cannot be maintained, and in the case of thickening and filtering sludge with a filter cloth in a siphon type, if the unconcentrated sludge in the filter thickening tank will The concentrated sludge attached to the outer surface of the filter cloth is peeled off by compressed air, etc., and the concentrated sludge (solid part) is dispersed due to the weak adhesion between the concentrated sludge and dissolves into the unconcentrated sludge to make the concentration The above prediction is common knowledge in this technical field.

Patent Document 1: Japanese Patent Laid-Open No. 2006-218455

Patent Document 2: Japanese Patent Laid-Open No. 2000-325998

Contents of the invention

Therefore, in view of the aforementioned conventional technical problems, an object of the present invention is to provide a suction filtration concentration method and a suction filtration concentration device that can efficiently discharge the concentrated sludge to the outside without redissolving the sludge. That is, to provide a suction filtration concentration method and a suction filtration concentration device, which can make the agglomeration of the concentrated sludge attached to the filter cloth hard and large by continuous suction under a predetermined suction pressure, and can be continuously pressed when peeling off. By sending water, the concentrated sludge can be peeled off in a state of hardness, size, and shape retention that cannot be redissolved. In particular, an object thereof is to provide a suction filtration concentration method and a suction filtration concentration device capable of reducing redissolution even when concentrated sludge is moved in water.

In order to achieve the above object, according to the present invention, a suction filtration concentration method and a suction filtration concentration device as shown below are provided.

〔1〕A suction filtration concentration method, which makes the sludge pass through the filter cloth in the filter concentration tank to perform suction filtration, so that the filtrate is recovered through the filter chamber inside the filter cloth, and the sludge is collected as concentrated sludge. Attached to the outer surface of the filter cloth, the method has the following steps: a sludge supply step, in which the sludge is supplied to the filter concentration tank; a filter concentration step, in which the sludge is supplied to the filter concentration tank The supplied sludge is subjected to filtration and concentration; a concentrated sludge stripping step in which the filtered and concentrated concentrated sludge is stripped from the outer surface of the filter cloth; and a concentrated sludge discharge step in which the stripped The concentrated sludge is discharged to the outside of the filter concentration tank. The filter concentration step has a step of using a predetermined suction pressure to the extent that the shape retention can be maintained even if the concentrated sludge is peeled off from the unconcentrated sludge, The suction is continuously performed so that the concentrated sludge adheres to the outer surface of the filter cloth, and the concentrated sludge stripping step has the following steps: The cloth continuously presses water for a predetermined time to peel off the concentrated sludge (filter residue) adhering to the outer surface of the filter cloth.

[2] The suction filtration concentration method according to [1], wherein the step of discharging the concentrated sludge includes removing the concentrated sludge accumulated in the bottom of the filter concentration tank from the unconcentrated sludge. A step of.

[3] The suction filtration concentration method according to [1] or [2], wherein the step of discharging the concentrated sludge consists of the step of concentration by filtration and the step of stripping the concentrated sludge after repeating a predetermined number of times. It is carried out after the cycle, and before the above-mentioned filtration concentration step in each cycle, there is a step of supplying sludge to the filter concentration tank by the above-mentioned sludge supply step.

[4] The suction filtration concentration method according to [1] or [2], wherein the concentrated sludge discharge step is performed in parallel in the filtration concentration step, and prior to the filtration concentration step, there is a The sludge supply step is a step of supplying sludge into the filter thickening tank.

[5] The suction filtration concentration method according to any one of [1] to [4], wherein the water sent to the filter chamber in the step of stripping the concentrated sludge is recycled to the filter Indoor filtrate.

[6] A suction filtration concentration device that performs suction filtration by allowing sludge to pass through a filter cloth, whereby the filtrate is recovered through a filter chamber inside the filter cloth, and the sludge is attached to the bottom of the filter cloth as concentrated sludge On the outer surface, the suction filter concentration device has: a sludge supply unit that supplies sludge into the filter concentration tank; a filter concentration unit that filters and concentrates the supplied sludge in the filter concentration tank; A unit that peels the concentrated sludge after filtration and concentration from the outer surface of the filter cloth; and a concentrated sludge discharge unit that discharges the peeled concentrated sludge to the outside of the filter concentration tank, the filter concentration unit has the following units , this unit utilizes a predetermined suction pressure that can maintain shape retention even if the concentrated sludge is peeled off in the unconcentrated sludge, and continuously sucks the concentrated sludge to the outer surface of the filter cloth, said The concentrated sludge stripping unit has a unit for continuously pressure-feeding water to the filter cloth for a predetermined time through the filter chamber among the supplied unconcentrated sludge, thereby removing the concentrated sludge adhering to the outer surface of the filter cloth. Mud (filter residue) stripping.

[7] The suction filtration concentration device according to [6], wherein the concentrated sludge discharge unit has a mechanism for removing agglomerated sludge accumulated at the bottom of the filter concentration tank from the unconcentrated sludge. unit.

[8] The suction filtration concentration device according to [6], wherein the concentrated sludge discharge unit is a mesh-shaped tray with a handle, which is arranged at the bottom of the filtration concentration tank, and the handle has The length that the upper opening of the concentration tank extends upwards.

[9] The suction filtration concentration device according to [6], wherein the concentrated sludge discharge unit is a bucket conveyor extending from the bottom of the filtration concentration tank through the upper opening of the filtration concentration tank to the outside. , so that the conveyor moving from the bottom of the filter concentration tank to the outside faces upward.

[10] The suction filtration concentration device according to [6], wherein, in the unit capable of continuously pressure-feeding water to the filter cloth through the filter chamber, a plurality of water supply pipes are arranged in the height direction of the filter cloth to The heights different from each other communicate with the filter chamber.

According to the suction filtration concentration method and the suction filtration concentration device according to the present invention, it is possible to efficiently discharge the concentrated sludge to the outside without redissolving the concentrated sludge before discharge. That is, it has the following effects: by continuously sucking under a predetermined suction pressure, the agglomeration of the concentrated sludge becomes hard and large, and the water is continuously pressure-fed when peeling off, thereby achieving a hardness and a size that will not be redissolved. And in the state of shape retention, the concentrated sludge is stripped. In particular, according to the method and apparatus of the present invention, redissolution can be prevented even if concentrated sludge is moved in water.

Description of drawings

Fig. 1 is a flow chart of the suction filtration concentration method of the present invention.

Fig. 2A is a schematic diagram showing one embodiment of the suction filtration concentration device of the present invention.

Fig. 2B is a schematic diagram showing another embodiment of the suction filtration concentration device of the present invention.

Fig. 2C is a schematic diagram showing another embodiment of the suction filtration concentration device of the present invention.

Fig. 2D is a schematic diagram showing another embodiment of the suction filtration concentration device of the present invention.

Fig. 2E is a schematic diagram showing another embodiment of the suction filtration concentration device of the present invention.

Fig. 2F is a schematic diagram showing another embodiment of the suction filtration concentration device of the present invention.

Fig. 2G is a schematic diagram showing another embodiment of the suction filtration concentration device of the present invention.

Fig. 3 is a schematic view showing a side surface of a filter plate in the suction filtration concentration device of the present invention.

4 is a schematic partial plan view showing a state in which a plurality of filter plates are suspended and supported by a filter concentration tank in the suction filtration concentration device of the present invention.

Fig. 5 is a perspective view showing a state in which a plurality of filter plates are arranged adjacent to each other in the suction filtration concentration device of the present invention.

Fig. 6A is a schematic diagram showing a state in which the filter cloth of the suction filtration concentration device of the present invention is inflated.

Fig. 6B is a schematic diagram showing a state of filtration with respect to the filter cloth of the suction filtration concentration device of the present invention.

Fig. 7 is a schematic diagram showing a process flow in one embodiment of the suction filtration concentration device of the present invention.

Fig. 8 is a schematic diagram showing a processing flow in another embodiment of the suction filtration concentration device of the present invention.

Fig. 9A is a flowchart of the suction filtration concentration method of the present invention.

Fig. 9B is a flowchart of the suction filtration concentration method of the present invention.

Fig. 10 is a schematic diagram showing a suction filtration concentration device according to another embodiment of the present invention.

Fig. 11A is a schematic diagram showing the peeling action in the suction filtration concentration device of the present invention.

Fig. 11B is a schematic diagram showing the peeling action in the suction filtration concentration device of the present invention.

Fig. 12 is a schematic configuration diagram of a suction filtration concentration device according to an embodiment of the present invention.

FIG. 13 is a graph showing the relationship between the peeling time and the peeling rate using the peeling pressure as a parameter regarding the test results of the test device in FIG. 12 .

Explanation of symbols

2: clean water tank, 4: sludge supply pipe, 6: sludge supply pump, 8: sludge supply valve, 10, 10A, 10B, 10C, 10D, 10E: suction filter concentration device, 12: filter concentration tank, 13 : Plane section, 14, 14A, 14B, 14C, 14D, 14E: Filter plate, 15: Horizontal tube, 16: Suction section, 18: Filter cloth, 20: Concentrated sludge stripping section, 22: Side wall, 24: Dirt Sludge supply/discharge pipe, 26: Sludge supply/discharge valve, 28: Sludge supply/discharge pump, 30: Concentrated sludge discharge pipe, 31: Suction pipe, 32: Concentrated sludge discharge valve, 33: Suction valve, 34, 34A, 34B, 34C, 34D, 34E,: distribution pipe, 35: vacuum pump, 36: filtrate storage tank, 38: filtrate discharge pipe, 40: filtrate discharge valve, 42: water inflow pipe, 44: water inflow valve, 46 : Liquid delivery pump, 47: Switching valve, 48: Filter frame, 50: Support plate, 54: Coil spring, 56, 57: Upper side, 58, 59: Lower side, 60, 61, 62, 63: Side side, 64: Extension, 65: Support member, 66A: Engaging plate, 67: Non-thickened sludge discharge pipe, 68: Non-thickened sludge discharge valve, 69: Inner side, 70, 70A, 72, 72A: Guide plate, 74: Wire trace, 76: filter chamber, 78: eyelet, 80: handle, 82: tray, 84a, 84b, 84c: bucket conveyor, 86: roller (drive roller), 88, 90, 92: roller, 89a, 89b, 89c: bucket, 108a, 108b, 108c: branch pipe, 112a, 112b, 112c: discharge valve, 113: suction pump, 114: flexible hose, 120: suction pump, 150: stripping pressure adjustment valve, 152: stock solution Tank, 154: stock solution pump, 156: thickened sludge discharge pump, 158: filter concentration tank, 160: washing water pump, 162: washing water tank, 164: washing water pressure adjustment valve, 166: compressor, 168: stock solution Discharge pump, C: Clean water, D: Interval, F: Filtrate, H: Specified height, P: Projection amount, R: Raw water, S: Movement amount, W: Concentrated sludge, X: Sludge, T1: Sewage Sludge supply step, T2: filtration thickening step, T3: thickened sludge stripping step, T4: thickened sludge discharge step.

Detailed ways

Hereinafter, embodiments of the suction filtration concentration method and apparatus according to the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the above embodiments. In addition, below, the case where the sludge produced|generated in a water purification plant, a sewage plant, etc. are made into filtration concentration object is demonstrated as an example.

[1] The composition of the suction filtration concentration method of the present invention:

The suction filtration concentration method of the present invention is shown in Figure 1, makes sludge pass through filter cloth in filter concentration tank and carries out suction filtration, thereby, makes filtrate pass through the filter chamber inside filter cloth and reclaim, and make sludge as The sludge is concentrated and attached to the outer surface of the filter cloth. In this method, the following steps are included: a sludge supply step (T1) in which sludge is supplied to the filter concentration tank; a filter concentration step (T2), in this step, the supplied sludge is filtered and concentrated in the filter concentration tank; the concentrated sludge stripping step (T3), in this step, the concentrated sludge after the filter concentration is removed from the filter cloth peeling of the outer surface; and a concentrated sludge discharge step (T4) in which the stripped concentrated sludge is discharged to the outside of the filter concentration tank, the above-mentioned filter concentration step (T2) has the following steps, that is, using In the non-thickened sludge, the predetermined suction pressure of the degree that the shape retention can be maintained even when the concentrated sludge is peeled off is continuously sucked, so that the concentrated sludge is attached to the outer surface of the filter cloth, and the above-mentioned concentrated sludge peeling step (T3 ) has a step of peeling off filter residue adhering to the outer surface of the filter cloth by continuously pressure-feeding water to the filter cloth for a predetermined time through the filter chamber in the supplied unconcentrated sludge.

According to the method of the present invention, the agglomeration of the concentrated sludge adhering to the filter cloth can be hardened without forming a layer, and can be peeled off as thickened sludge of a larger agglomerate sheet. Therefore, even in non-thickened sludge, the concentrated sludge of agglomerated pieces is rarely redissolved, and the concentrated sludge can be efficiently taken out. That is, the liquid to be treated is filtered by continuously sucking the liquid to be treated containing the object of filtration concentration under a predetermined suction pressure non-intermittently, and passing it through the filter cloth, and passing through a large number of fine pores provided on the filter cloth. . The filtrate was recovered as indicated above. On the other hand, the object to be filtered and concentrated cannot pass through a large number of pores and adheres to the outer surface of the filter cloth, thereby being concentrated, and the adhesion to the filter cloth is also ensured. In other words, by non-intermittently and continuously suctioning, the concentrated sludge (filter residue) is formed into dense and relatively hard concentrated sludge agglomerates on the outer surface of the filter cloth.

In addition, after the completion of filtration and concentration, in the liquid to be treated after filtration and concentration, water is continuously pressure-fed to the filter cloth for a predetermined time from the surface opposite to the surface on which the concentrated sludge is attached. At this time, the pressure-fed water (hereinafter, appropriately referred to as "pressure-fed water") passes through a large number of pores of the filter cloth and flows out into the liquid to be treated. However, the concentrated sludge adheres to the entire outer surface of the filter cloth and clogs many fine pores of the filter cloth. Therefore, the hydraulic pressure of the liquid to be treated is similarly carried on the outer surface to which the concentrated sludge adheres. That is, the concentrated sludge adhering to the outer surface of the filter cloth is pressed into the liquid to be treated until the hydraulic pressure of the water pressure-fed into the filter chamber at least overcomes the hydraulic pressure of the liquid to be treated. Therefore, the concentrated sludge will not be peeled off from the surface of the filter cloth until the hydraulic pressure of the water pressure-fed into the filter chamber at least overcomes the hydraulic pressure of the liquid to be treated. Thereby, the pressure of the pressure-fed water in the filter chamber rises, and at the same time, the filter cloth is expanded.

Here, since the pressure-fed water is liquid water, it has incompressibility compared with gas such as air. Therefore, it is possible to prevent the conventional peeling by air in the atmosphere. That is, in the case of conventional air pressure feeding, since the local pressure in the filter chamber rises, the concentrated sludge adhering to the surface of the filter cloth is locally injected into the liquid to be treated from the filter cloth close to this part. press. It is possible to prevent the pressed concentrated sludge from peeling off from the surface of the filter cloth, and air continue to flow out only from the pores opened thereafter. In other words, in the present invention, the concentrated sludge adhering to the surface of the filter cloth can be poured into the liquid to be treated at the same time when the hydraulic pressure of the pressure-fed water reaches a predetermined pressure in the filter chamber as a whole. press. Therefore, the concentrated sludge (filter residue) can be uniformly peeled off from the surface of the filter cloth in the circumferential direction.

In addition, in the present invention, since the sludge is continuously sucked under a predetermined suction pressure, dense and hard concentrated sludge is formed on the surface of the filter cloth, and the adhesion to the filter cloth is also increased. Therefore, even if the suction is stopped and the sludge is pressed all at once into the liquid to be treated, the concentrated sludge will not be peeled off while being broken into layers. That is, when the lumps of concentrated sludge attached to the filter cloth in a densified and relatively hard state are peeled off, the unconcentrated sludge accumulated in the filter concentration tank will be treated as relatively hard and large lumps of concentrated sludge. in the sludge. Therefore, when discharged from the filter concentration tank, the agglomerated pieces of the concentrated sludge are not easily broken into small pieces or redissolved, and the concentrated sludge can be efficiently and easily discharged to the outside of the filter concentration tank.

In the present invention, as the suction filtration method, a siphon suction filtration method or a suction filtration method using a suction pump can be employed.

Next, the suction filtration concentration method of the present invention will be described corresponding to the suction filtration concentration device of the present invention. Here, the suction filtration concentration device and method of the siphon type will be described.

(2) The structure of the suction filtration concentration device of the present invention:

The suction filtration concentration device of the present invention is shown in Fig. 2A ~ Fig. 2G, makes sludge pass through filter cloth and carries out siphon type suction filtration, thereby makes filtrate pass through the filter chamber inside filter cloth to be recovered, and makes sludge become concentrated sewage. Mud (filter residue) is attached to the outer surface of the filter cloth, and the device is constituted as a siphon suction filter concentration device 10, which has: a sludge supply unit, which supplies sludge to the filter concentration tank; a filter concentration unit, which The supplied sludge is filtered and concentrated in the filter concentration tank; the concentrated sludge stripping unit that strips the filtered and concentrated concentrated sludge from the outer surface of the filter cloth; and the concentrated sludge discharge unit that strips the stripped concentrated sludge It is discharged to the outside of the filter concentration tank, and the above filter concentration unit has a unit that uses a predetermined suction pressure to maintain shape retention even if the filter residue is peeled off in the unconcentrated sludge, and continuously sucks, so that Concentrated sludge (filter residue) adheres to the outer surface of the filter cloth, and the above-mentioned concentrated sludge stripping unit has the following unit, that is, through the filter chamber to the filter cloth through the supplied unconcentrated sludge continuously with a predetermined Time pressure to send water, so as to peel off the filter residue attached to the outer surface of the filter cloth.

Specifically, the siphon type suction filter concentration device 10 is roughly composed of the following parts as shown in Figures 2A to 2E, namely: a filter concentration tank 12, which accommodates the sludge as a filter concentration target; a filter plate 14, which It is arranged in the filter concentration tank 12; the suction part 16, which attracts sludge; the concentrated sludge stripping part 20, which strips the concentrated sludge, and the concentrated sludge is attached to the filter plate 14 by using the suction part 16 The outer surface of the filter cloth 18; and the concentrated sludge removal part 23, which is used to discharge the concentrated sludge peeled off by the concentrated sludge peeling part 20 and accumulated in the agglomerated sheet at the bottom of the filter concentration tank 12. In addition, if necessary, a concentrated sludge discharge pipe 30 and a concentrated sludge discharge valve 32 for discharging agglomerated small pieces or liquid concentrated sludge are also provided. By opening the concentrated sludge discharge valve 32, the agglomerated flakes or liquid concentrated sludge accumulated at the bottom of the filter concentration tank 12 fall under the action of gravity, and are discharged to the outside through the concentrated sludge discharge pipe 30. . In addition, the concentrated sludge discharge pipe 30 and the concentrated sludge discharge valve 32 are large diameters capable of discharging small pieces of concentrated sludge, for example, preferably having a nominal diameter of 200A or more (200mmφ or more).

(Sludge supply step/Sludge supply unit)

A sludge supply process (means) is a process (means) of supplying sludge into the filter concentration tank 12 which is a filter concentration tank. That is, the sludge supply means is roughly comprised by the sludge supply/discharge pipe 24 shown to FIG. 2A - FIG. 2F, the sludge supply/discharge valve 26, the sludge supply/discharge pump 28, etc. FIG. In addition, the sludge supply process in the sludge supply step (T1) shown in FIG. of. However, it is not limited to this. In addition, a sludge supply pump and a discharge pump may be provided separately and it may be made into a different system.

More specifically, the filtration concentration tank 12 is a container having a bottomed rectangular cross section, and has a volume capable of installing a filter plate 14 described later inside. One end of a sludge supply/discharge pipe 24 that supplies sludge into the filter concentration tank 12 communicates with the side wall 22 of the filter concentration tank 12 . Moreover, the sludge supply/discharge pump 28 which can operate normally and reversely is connected via the sludge supply/discharge valve 26 provided in the middle of the sludge supply/discharge pipe 24. As shown in FIG. Thereby, by opening the sludge supply/discharge valve 26 and operating the sludge supply/discharge pump 28, the sludge can be supplied into the filtration thickening tank 12. In addition, the unconcentrated sludge in the filter concentration tank 12 can be discharged from the filter concentration tank 12 by operating the sludge supply/discharge pump 28 in reverse.

In addition, in FIGS. 2A to 2F, the sludge is supplied to the filter concentration tank 12 through the sludge supply/discharge pipe 24, but as shown in FIG. Raw water R is separated into purified water C and sludge X in advance, and the sludge X is supplied to the filtration concentration tank 12 . The sludge X is supplied to the filter concentration tank 12 through the sludge supply pipe 4 by opening the sludge supply valve 8 and operating the sludge supply pump 6 . The separated clean water C is further processed on the downstream side, and is utilized as drinking water, for example. In addition, the clean water tank 2 may be of a currently known structure, and raw water is put into the tank and, for example, a coagulant is added to the tank to separate the raw water into clean water and sludge.

(Filter Concentration Step/Filter Concentration Unit)

The filtration concentration step (unit) is a step (unit) in which the sludge supplied from the sludge supply step (unit) is further subjected to filtration concentration in the filtration concentration tank. That is, the filtration concentration step (T2) shown in FIG. 1 is a step of continuously performing suction using a predetermined suction pressure that maintains shape retention even if the concentrated sludge (filter residue) is peeled off from the unconcentrated sludge. . And, it is a step of making the concentrated sludge (filter residue) adhere to the outer surface of the filter cloth by this continuous suction. The filtration concentration treatment in this filtration concentration step ( T2 ) is realized by, for example, a filtration concentration unit having a filter plate 14 , a suction pipe 31 , a suction valve 33 , a distribution pipe 34 , a vacuum pump 35 and the like shown in FIGS. 2A to 2G . However, it is not limited to this.

Specifically, the filter plate 14 is connected at its upper portion to a filtrate storage tank 36 via a distribution pipe 34 . The filtrate storage tank 36 is arranged outside the filter concentration tank 12 , and one end of the filtrate discharge pipe 38 communicates with and is connected to the filtrate storage tank 36 . The filtrate discharge pipe 38 extends vertically downward, and a filtrate discharge valve 40 is provided in the middle.

In addition, the distribution pipe 34 and the filtrate discharge pipe 38 are connected in an inverted U shape through the filtrate storage tank 36 . Thereby, the filtrate filtered in the filter concentration tank 12 is discharged to the outside of the filter concentration tank 12 by utilizing the siphon principle. In addition, the suction pipe 31 is branched and connected to the distribution pipe 34 , and is connected to a vacuum pump 35 via a suction valve 33 provided in the middle. Accordingly, when the vacuum pump 35 is operated with the suction valve 33 opened, the liquid treated in the filter concentration tank 12 is sucked into the distribution pipe 34 . As described above, the filtrate can be discharged to the outside through the filtrate discharge pipe 38 by utilizing the siphon principle.

Here, the suction pressure of the siphon is determined corresponding to the height difference between the end and the top of the inverted U-shaped pipe composed of the distribution pipe 34 and the filtrate discharge pipe 38 . However, the suction pressure actually used in the suction filtration concentration device 10 is preferably 0.02 MPa to 0.08 MPa. By continuously sucking the sludge in the filtration thickening tank 12 using such relatively low suction pressure, the thickened sludge can be made to adhere to the outer surface of the filter cloth 18 . In particular, through continuous suction, the adhesion and hardness of the concentrated sludge to the outer surface of the filter cloth 18 can be obtained to the extent that even if the concentrated sludge is removed from the filter cloth 18 by the concentrated sludge peeling part 20 Peeling can also maintain the shape retention of the concentrated sludge which is an agglomerated piece in the non-concentrated sludge in the filter concentration tank 12 . The criterion of continuous suction is to continuously continue suction until the thickness of the concentrated sludge adhering to the filter cloth becomes about 5 mm to 20 mm, preferably 8 mm to 15 mm. The suction duration at this time is about 30 minutes to 4 hours. In addition, the suction method in the present invention is not limited to the siphon type, and the above-mentioned suction pressure may be generated by a suction pump such as a vacuum pump.

In addition, as shown in FIG. 5 , a plurality of filter plates 14 are arranged in the filter concentration tank 12 in a state in which the planar portion 13 extends in the vertical direction. That is, the plurality of filter plates 14 ( 14A to 14E) are arranged adjacent to each other with a predetermined interval D therebetween. The smaller the distance D between adjacent filter plates 14, the more the number of filter plates 14 that can be installed in the filter concentration tank 12 increases, thereby increasing the total filtration area. However, the intervals between adjacent filter plates 14 may be determined from the viewpoint of securing the maximum filtration area without causing adjacent filter plates 14 to contact each other. This is because the filter cloth 18 needs to be expanded in order to peel off the concentrated sludge adhering to the filter cloth 18 of the filter plate 14 . That is, the reason is that due to the expansion of the filter cloth 18, the filter cloth 18 protrudes toward the adjacent filter plate 14, so the filter cloth 18 may contact the adjacent filter plate 14, and the filtering area is reduced, thereby making it impossible to Filter well.

(Thickened sludge stripping step/Thickened sludge stripping unit)

The concentrated sludge peeling step (unit) is a step (unit) of peeling the concentrated sludge filtered and concentrated in the filtration concentration step (unit) from the outer surface of the filter cloth. This thickened sludge stripping step (unit) has the following step (unit): using a predetermined suction pressure to the extent that the shape retention can be maintained even if the thickened sludge (filter residue) is stripped from the non-thickened sludge, continuously Suction is performed so that concentrated sludge (filter residue) adheres to the outer surface of the filter cloth. As this concentrated sludge detachment means (concentrated sludge detachment part 20), the unit which has the water inflow pipe 42, the water inflow valve 44, the liquid transfer pump 46, etc. which are shown in FIGS. 2A-2G is mentioned, for example. In addition, the filter plate 14 may be a member which comprises the concentrated sludge peeling means. And the peeling of the concentrated sludge in this concentrated sludge peeling process (T3) shown in FIG. However, it is not limited to this.

Specifically, one end of the water inflow pipe 42 communicates with and is connected to the filtrate storage tank 36 , and a water inflow valve 44 and a liquid delivery pump 46 are connected therebetween. Thus, when the liquid feed pump 46 is operated with the water inflow valve 44 opened, water (pressure-fed water) is supplied to the filter chamber 76 ( will be described later) supply. In the present embodiment, the filtrate of the filtrate storage tank 36 is used as pressure-fed water, and a switching valve 47 is provided for this purpose. As mentioned above, when peeling concentrated sludge from the filter cloth 18, the filter cloth 18 is expanded. In this case, the peeling pressure and/or the peeling time can be adjusted using the liquid transfer pump 46 and the water inflow valve 44 so that the attached concentrated sludge is peeled off from the filter cloth 18 as an agglomerated sheet.

Here, in the concentrated sludge stripping step (unit), when the sludge is the subject of filtration and concentration, it is important to continuously press-feed the water as the stripping medium for a predetermined time, not intermittently. That is, by continuously pressure-feeding water as a stripping medium for a predetermined time, even if the concentrated sludge adhering to the filter cloth is stripped in the non-concentrated sludge, the concentrated sludge can not be dissolved in the non-concentrated sludge. , but maintains shape retention as an agglomerated sheet. In addition, in the concentrated sludge stripping step, it is preferable to use the filtrate recovered in the filter chamber 76 as described above as the water pressure-fed into the filter chamber 76 . That is, it is preferable to use the filtrate obtained by filtering the sludge with the filter cloth 18 and recovering it in the filter chamber 76 as the water of the peeling medium of the concentrated sludge.

In addition, the filter plate 14 is roughly composed of the following parts as shown in FIGS. It accommodates a support plate 50 inside; and a plurality of coil springs 54 which are disposed between the filter frame 48 and the support plate 50 . The filter frame 48 is formed in a hollow rectangular shape with an upper side 56, a lower side 58, and two sides 60, 62 between the upper and lower sides. The filter plate 14 is suspended and supported by the inner surface of the filter concentration tank 12 by both ends of the upper side 56 . More specifically, as shown in FIGS. 3 and 4 , extensions 64 are respectively provided at both ends of the upper side 56 . On the other hand, a pair of guide plates 70 ( 70A) and 72 ( 72A) protruding inwardly are provided on the inner surface 68 of the filter concentration tank 12 . Moreover, the end part of the extension part 64 (64A, 64B, 64C) is arrange|positioned between a pair of guide plate 70 (70A), 72 (72A). Moreover, the engaging plate 66A fixed to the upper surface of the extension part 64 (64A, 64B, 64C) is placed on the upper surface of a pair of guide plate 70 (70A), 72 (72A). Accordingly, each filter plate 14 is suspended and supported on the filter concentration tank 12 . The distance between adjacent filter plates 14 is determined by selecting a pair of guide plates 70 ( 70A) and 72 ( 72A) for suspending and supporting the filter plates 14 . However, the distance D between adjacent filter plates 14 may be appropriately changed. As this case, for example, the following cases can be mentioned, that is: corresponding to the adhesion amount of the concentrated sludge on the filter cloth 18, the magnitude of the negative pressure generated by suction, the transverse division length of the filter cloth 18, etc., and A pair of guide plates 70 ( 70A), 72 ( 72A) are selected for suspending and supporting the filter plate 14 .

The support plate 50 is made of a net, a screen, or the like, and is formed in a rectangular shape. In addition, a large number of small openings are provided on the support plate 50 . In addition, on the surface of the support plate 50, a concave-convex portion (not shown) extending in the vertical direction is provided. Between the concave portion of the support plate 50 and the inner surface of the filter cloth 18, a plurality of filtrate flow paths extending in the vertical direction of the support plate 50 are formed. Such a support plate 50 is preferably formed of a hard material so that the in-plane elongation of the support plate 50 accompanying the immersion of the filter cloth 18 in the sludge does not substantially occur, or the plane of the support plate 50 is not damaged. Sexual deformation. In addition, it is preferably formed of a hard material so that shrinkage in the plane of the support plate 50 accompanying expansion of the filter cloth 18 or deformation that impairs the planarity of the support plate 50 does not substantially occur. For example, resin is more preferable. Specifically, for example, it may be made of polyethylene or EVA resin. By adopting such a material, when the filter cloth 18 is immersed in sludge for a long time, or when the filter cloth 18 is expanded, the coil spring 54 described later can be used to act on the filter plate 14 (support plate 50 ). The tension is kept approximately constant continuously.

The filter cloth 18 is preferably made of chemical fiber or metal, and in the case of chemical fiber, nylon, polypropylene, or polyester is particularly preferable. For example, as the type of fiber, monofilament threads that have a good cleaning effect and are less prone to clogging can be used. If emphasis is placed on strength and fine particle trapping, a multifilament obtained by twisting a plurality of fibers may be used. In addition, the diameter of the thread|yarn to be used should just consider the intensity|strength, elongation, etc. of the filter cloth 18 required, and should just decide suitably for each of a warp thread and a weft thread. As for the weaving method of the fabric, satin weave can be used, which has a high cleaning effect and is less likely to cause clogging of the mesh. Plain weave and twill weave can also be used if the thickness of the mesh and the trapping property of fine particles are important. In addition, the density of the weaving thread may be appropriately determined for each of the warp and the weft in consideration of the required strength, elongation, and the like of the filter cloth 18 . For example, the filter cloth 18 may be formed in a bag shape in which a pair of rectangular cloths were overlapped and peripheral edges were sewn together. Alternatively, one sheet of rectangular cloth body may be bent so that opposing edge portions overlap each other, and the peripheral edge portions may be sewn together into a bag shape. Around this filter cloth 18 , a plurality of holes 78 are provided, and one end of the coil spring 54 is hooked in the holes 78 .

In addition, as shown in FIGS. 2A to 2G and FIG. 3 , on the filter cloth 18, a plurality of stitches 74 extending in the up-and-down direction of the filter concentration tank 12 are provided, and each stitch 74 is used to connect the filter cloth 18 to the container. The supporting plate 50 inside it is integrally sewn. Thereby, as shown in FIGS. 6A and 6B , filter chambers 76 partitioned by adjacent stitches 74 are formed inside the filter cloth 18 . The horizontal pipe 15 (refer FIG. 3) provided in the upper part in the filter cloth 18 is connected to the front-end|tip of the branch pipe 34. As shown in FIG. Outflow holes (not shown) communicating with the filter chambers 76 are provided downward on the horizontal pipe 15 . In addition, water as a peeling medium is pressure-fed into each filter chamber 76 through the branch pipe 34 and the outflow hole provided in the horizontal pipe 15 . In addition, FIG. 6A is a schematic diagram showing a state in expansion, and FIG. 6B is a schematic diagram showing a state in filtering.

In addition, when the length of the filter cloth 18 in the vertical direction is long and the hydraulic pressure difference of the sludge in the filter thickening tank 12 is large, it is also possible to arrange a plurality of water supply pipes so that they are different from each other along the height direction of the filter cloth 18. The height is connected with the filter chamber. For example, when the concentrated sludge adhering to the filter cloth 18 is peeled off using water as a peeling medium, the filter cloth 18 may be loaded and the hydraulic pressure of the sludge in the filter thickening tank 12 may vary in the height direction. In this case, if a plurality of water supply pipes are set at the same height along the height direction of the filter cloth, the concentrated sludge cannot be peeled off in the same way along the height direction of the filter cloth, and it is difficult to peel off as agglomerated pieces, which is easy to cause disadvantages. However, this disadvantage can be prevented by providing a plurality of water supply pipes at different heights from each other along the height direction of the filter cloth 18 as the water pressure feeding means that can continuously pressure feed water to the filter cloth through the filter chamber. In addition, as another example, for example, water with a relatively low water pressure may be pressure-fed to the upper portion of the filter cloth 18 with a low hydraulic pressure, and water with a relatively high water pressure may be pressure-fed to the lower portion of the filter cloth 18 with a high hydraulic pressure. However, the hydraulic pressure difference in the vertical direction is smaller than the pressure (0.1 to 1.0 MPa) at the time of water delivery, and can be ignored if it does not become a problem.

Here, the coil spring 54 is a member for adjusting the tension acting on the filter plate (specifically, the support plate 50 ) to be substantially constant continuously. Specifically, as shown in Figure 3, a plurality of coil springs 54 are arranged between the side 60 of the filter frame 48 and the side 61 of the filter cloth 18, the side 62 of the filter frame 48 and the side 63 of the filter cloth 18. Between, between the lower edge 58 of the filter frame 48 and the lower edge 59 of the filter cloth 18, and between the upper edge 56 of the filter frame 48 and the upper edge 57 of the filter cloth 18. The intervals between adjacent coil springs 54 provided on both sides and upper and lower sides of the filter frame 48 may be appropriately set according to the size of the filter cloth 18 and the amount of concentrated sludge attached. Specifically, one end of each coil spring 54 is hooked in the hole 78 of the filter cloth 18 and the other end is fixed to the sides 60 , 62 , upper 56 and lower 58 of the filter frame 48 . From the viewpoint of corrosion resistance, it is preferable that the plurality of coil springs 54 are made of SUS. In addition, generally, dozens of coil springs 54 are arranged around the filter plate 14, and the number of filter plates 14 is, for example, several tens, so it is preferable not to use a custom-made one but to use a standard one.

In addition, when the filter plate 14 (14A, 14B, 14C, 14D, 14E) and the filter cloth 18 are large and weigh a predetermined amount or more, as shown in FIGS. Between the upper side 57 of the filter cloth 18, instead of the coil spring 54, a highly rigid support member 65 is provided to fix the heavy filter cloth 18 and the support plate 50 so as not to expand or contract. The reason is that when the weight of the filter cloth 18 and the support plate 50 becomes larger than or equal to a predetermined amount, the coil spring 54 on the upper side of the filter cloth 18 is extended, and the coil spring 54 on the lower side of the filter cloth 18 is contracted. Then the tension acting on the filter cloth 18 and the support plate 50 cannot become a constant value, and the filter cloth 18 and the support plate 50 move due to a small external force. The operation of conveying and stripping the concentrated sludge causes adverse effects.

(Concentrated sludge discharge step/Concentrated sludge discharge unit)

The thickened sludge discharge step (unit) is a step (unit) of discharging the stripped thickened sludge to the outside of the filter thickening tank. In the present embodiment, the concentrated sludge discharge step (means) does not discharge the unconcentrated sludge in the filter concentration tank 12 . As the concentrated sludge discharge unit, the sludge supply/discharge valve 26, the sludge supply/discharge pump 28, the sludge supply/discharge pipe 24, the concentrated sludge removal part 23 ( Mesh tray 82) etc. The concentrated sludge discharge process in the concentrated sludge discharge process (T4) shown in FIG. 1 is realized by the said concentrated sludge discharge means.

The thickened sludge discharge process (unit) has the process (unit) of taking out the thickened sludge of agglomerated sheet accumulated in the bottom of a filter thickening tank among unconcentrated sludge. With the configuration as described above, the unconcentrated sludge is not discharged from the filter thickening tank as in the prior art, but the thickened sludge accumulated in the bottom of the filter thickening tank can be collected in the unconcentrated sludge fish out. That is, continuous treatment of concentrated sludge can be performed. In addition, in a state having hardness, size, and shape retention that cannot be redissolved, even if the peeled concentrated sludge (concentrated sludge of agglomerated pieces) moves in water, it can be discharged in a state that cannot be redissolved . Therefore, the concentrated sludge can be easily and efficiently discharged from the filter thickening tank to the outside without reducing the degree of concentration of the concentrated sludge. So far, the sludge filtration and concentration operation is completed. The concentrated sludge discharged to the outside of the filter concentration tank 12 is further concentrated by another dehydrator, formed into agglomerates again, and is incinerated or landfilled.

In addition, in the step of discharging the concentrated sludge, if necessary, by using other steps than the step of discharging the concentrated sludge of the above-mentioned agglomerated pieces, the small pieces of agglomerated or liquid concentrated sludge accumulated at the bottom of the filter concentration tank 12 The sludge is discharged through the concentrated sludge discharge pipe 30 to discharge the concentrated sludge to the outside of the filter concentration tank 12 . At this time, the non-concentrated sludge in the filter concentration tank 12 may be discharged in advance, or may be discharged from the concentrated sludge discharge pipe 30 together with these concentrated sludges.

As said concentrated sludge discharge means, the concentrated sludge removal part 23 shown in FIG. 2A-FIG. 2G, FIG. And, the concentrated sludge discharge process in the concentrated sludge discharge step is realized by the above-mentioned concentrated sludge discharge means. Specifically, the concentrated sludge removal part 23 is arranged at the bottom of the filter concentration tank 12, and has concentrated sludge for removing the agglomerated pieces peeled off by the concentrated sludge peeling part 20 and accumulated in the bottom of the filter concentration tank 12. role. The concentrated sludge extraction part 23 in this embodiment has the mesh-shaped tray 82 with the handle 80 which has the length which extends upward from the upper opening of the filtration thickening tank 12. As shown in FIG.

Here, the size of the mesh-shaped tray 82 is preferably such that it covers the entire bottom of the filter concentration tank 12 so that the concentrated sludge accumulated in the bottom of the filter concentration tank 12 can be pulled out without leakage. The size of the mesh may be appropriately determined in relation to the size of the agglomerated pieces of the concentrated sludge. However, it is preferable to select the size of the mesh in such a manner that when the mesh tray 82 is lifted upward using the handle 80, the moisture in the concentrated sludge is removed through the screen, and the concentrated sludge is held on the screen. online.

In addition, in order to pull out the mesh-shaped tray 82 to its upper part, it is provided in the filter concentration tank 12 to ensure that most of the interval (for example, wider than D in FIG. shape tray 82. Below the filter plate 14, a wire mesh belt conveyor is set at the bottom of the filter thickening tank 12, and the wire mesh belt conveyor is used to receive the concentrated sludge of the stripped agglomerated sheet, and horizontally It is conveyed to the mesh tray 82 . Instead of this conveyor, a scraper may be provided to transport the peeled agglomerated concentrated sludge to the mesh tray 82 . When the space of the filter concentration tank 12 has a margin, the mesh tray 82 can also be arranged directly below the filter plate 14, and the handle 80 is used to make the mesh tray 82 itself move laterally at the bottom of the filter concentration tank 12. Then, the mesh tray 82 can be lifted upward, and the mesh tray 82 can be taken out to the outside.

In addition, as another embodiment, as shown in FIG. 10 , bucket conveyors 84 (84a, 84b, 84c) may also be used to transfer the concentrated sludge W in the form of agglomerated sheets accumulated at the bottom of the filter concentration tank 12 to External discharge. For example, the following bucket conveyor 84 can be cited as an example. The bucket conveyor 84 extends from the bottom of the filter concentration tank 12 through the upper opening of the filter concentration tank 12 to the outside, so that the bottom of the filter concentration tank 12 goes outward. The moving conveyor is disposed facing upward.

For example, when there is a space restriction due to the arrangement of the filter plate 14 in the filter concentration tank 12, it is preferable to use three sets of bucket conveyors 84a, 84b, and 84c as shown in FIG. 10 .

Specifically, in the first group of bucket conveyors 84 a , one side is configured as a driving roller 86 , and the conveyor is stretched between two rollers 86 and 88 arranged at the bottom of the filter concentration tank 12 . Moreover, it is comprised so that several buckets 89a may be provided on the conveyor which was erected, and the conveyor will move along the bottom surface of the filter concentration tank 12. As shown in FIG. Moreover, in the 2nd group bucket conveyor 84b, the roller 90 of one side is arrange|positioned above the filter concentration tank 12. As shown in FIG. Moreover, it is comprised so that several buckets 89b may be provided in the conveyor which spanned between the two rollers 88 and 90, and the conveyor moves along the side wall of the filter concentration tank 12. As shown in FIG. In addition, in the third group of bucket conveyors 84c, the two rollers 90, 92 are arranged above the filter thickening tank 12 (the upper part of the sludge accommodated in the filter thickening tank 12), and the conveyor is mounted on the two rollers 90. , Between 92. Moreover, it is comprised so that several buckets 89c may be installed in this conveyor. As described above, if three sets of bucket conveyors 84a, 84b, and 84c are used, for example, the operation of discharging the concentrated sludge can be performed in parallel with the operation of filtering and concentrating the unconcentrated sludge. That is, three sets of bucket conveyors 84a, 84b, and 84c can be used to transport the thickened sludge taken out by the buckets of the first set to the second and third sets of bucket conveyors, and finally to the filter thickening tank. 12 External discharge.

In addition, the bucket conveyor is not limited to the above-mentioned example, For example, the conveyor which can change the route by installing a roller in the middle using one set of bucket conveyors may be sufficient.

In addition, instead of such a bucket conveyor, a wire mesh belt conveyor extending from the bottom of the filter concentration tank 12 to the outside through the upper opening of the filter concentration tank 12 may be used. In this case, similarly, the belt conveyor arrange|positions so that the conveyor surface which moves to the outside from the bottom part of the filtration concentration tank 12 may face upward.

In addition, as another embodiment, in the step of discharging concentrated sludge (D) shown in FIG. 7 and FIG. , The wire mesh belt conveyor preferably adopts the following structure, that is, it extends to the bottom portion of the filter concentration tank 12 without the filter plate 14 above, and is connected to the bucket there. In the case of the present embodiment, the thickened sludge W of agglomerated pieces falling from the filter plate 14 is placed on a wire mesh belt conveyor and transported to a bucket, where it can be taken out to the outside of the filter thickening tank 12. .

As the non-concentrated sludge discharge means, the non-concentrated sludge discharge pipe 67 is provided, and the non-concentrated sludge is discharged. In addition, it is preferable that the unconcentrated sludge discharge pipe 67 is connected to the filter concentration tank at a predetermined height above the bottom of the filter concentration tank so as not to discharge the concentrated sludge accumulated in the bottom of the filter concentration tank.

Specifically, one end of an unconcentrated sludge discharge pipe 67 for discharging unconcentrated sludge in the filter concentrator 12 communicates at a predetermined height H above the bottom of the filter concentrator 12 . In the middle of the non-concentrated sludge discharge pipe 67, the non-concentrated sludge discharge valve 68 is provided. This predetermined height H is set above the height of the thickened sludge of agglomerated sheets accumulated in the bottom of the filtration thickening tank 12 . For example, it is provided above the upper end of the mesh tray 82 . By setting the predetermined height H as described above, the thickened sludge peeled off from the filter cloth 18 and accumulated at the bottom of the filter thickening tank 12 can be prevented from being discharged to the outside together with the unthickened sludge discharge pipe 67 . discharge. In addition, as shown in FIG. 2B, at the bottom of the filter concentration tank 12, one end of the concentrated sludge discharge pipe 30 for discharging the small pieces of agglomerated or liquid concentrated sludge accumulated in the bottom of the filter concentration tank 12 is connected. . Moreover, the concentrated-sludge discharge valve 32 is provided in the middle of the concentrated-sludge discharge pipe 30. As shown in FIG. By opening the concentrated sludge discharge valve 32 , the concentrated sludge accumulated at the bottom of the filter concentration tank 12 falls by gravity and is discharged to the outside through the concentrated sludge discharge pipe 30 .

That is, in the process of settling the concentrated sludge in the form of agglomerated flakes in the non-concentrated sludge to the lower part of the filter concentration tank 12, it is necessary to separate the non-concentrated sludge and the concentrated sludge and discharge them to the outside. In this case, when the unconcentrated sludge is discharged from the unconcentrated sludge discharge pipe connected to the bottom of the filter thickening tank 12, the unconcentrated sludge is mixed with the concentrated sludge, making it difficult to recover only the unconcentrated sludge. Alternatively, the discharge port connected to the non-concentrated sludge discharge pipe may be blocked due to the thickened sludge having the shape-retaining agglomerated sheet, and even recovery of the non-concentrated sludge may become difficult. Therefore, according to the suction filter thickening device having the above-mentioned structure, when the unconcentrated sludge is discharged through the unconcentrated sludge discharge pipe, the concentrated sludge of agglomerated sheets accumulated at the bottom can not be discharged, and only the unconcentrated sludge can be discharged. The mud is efficiently discharged to the outside. In addition, in the present embodiment, the unconcentrated sludge discharged outside is resupplied to the filter concentration tank 12 by the sludge supply valve 26, the sludge supply pump 28, etc. in a circulating manner (pipelines are not shown).

In addition, as another example, a second non-concentrated sludge discharge pipe (not shown) may be further provided between the bottom of the filter concentration tank 12 and the non-concentrated sludge discharge pipe 67 . That is, when discharging the non-concentrated sludge to the outside, the non-concentrated sludge is first discharged to the outside from the non-concentrated sludge discharge pipe 67 . Then, the unconcentrated sludge remaining from the bottom of the filter thickening tank 12 to the predetermined height H is discharged to the outside from the second unconcentrated sludge discharge pipe. When the second unconcentrated sludge discharge pipe is provided as described above, instead of discharging the unconcentrated sludge through the second unconcentrated sludge discharge pipe from the beginning, the unconcentrated sludge discharge pipe 67 first discharges the unconcentrated sludge. The unconcentrated sludge is discharged to the outside, and the height of the unconcentrated sludge in the filter thickening tank 12 is temporarily lowered to lower the water pressure. Therefore, the unconcentrated sludge remaining to the predetermined height H from the bottom of the filter concentration tank 12 can be discharged while limiting the amount of concentrated sludge discharged together with the unconcentrated sludge. In particular, when the thickened sludge accumulated in the agglomerated sheet at the bottom of the filter thickening tank 12 is large, the discharge port provided at the bottom of the filter thickening tank 12 may be discharged through the second unconcentrated sludge discharge pipe. The thickened sludge is clogged. Therefore, while the unconcentrated sludge remaining below the predetermined height H can be discharged to some extent, the concentrated sludge is not discharged to the outside.

In addition, as an example of other non-concentrated sludge discharge pipes, there may be a plurality of branch pipes connected to the above-mentioned non-concentrated sludge discharge pipe in parallel. The valve is connected with the above-mentioned filter concentration tank. For example, as shown in FIG. 2C, the unconcentrated sludge discharge pipe 67 is comprised so that it may have three branch pipes 108a, 108b, and 108c connected to the unconcentrated sludge discharge pipe 67 in parallel. In addition, each branch pipe 108a, 108b, 108c is connected to the filter concentration tank 12 through discharge valves 112a, 112b, 112c at different heights above the bottom of the filter concentration tank 12 . In addition, a suction pump 120 is provided on the unconcentrated sludge discharge pipe 67 . According to the device having the above structure, it is possible to select one of the three branch pipes 108a, 108b, and 108c to pass the unconcentrated sludge according to the sedimentation height of the concentrated sludge accumulated at the bottom of the filter concentration tank 12. The unconcentrated sludge is discharged through the discharge pipe 67. For example, when the sedimentation height of the concentrated sludge is closest to the branch pipe 108c at the lowest height from the bottom of the filter concentration tank 12, the discharge valve 112c of the branch pipe at the lowest height is closed. On the other hand, by opening the discharge valves 112a and 112b of the branch pipes of the second and third heights and operating the suction pump 120, the concentrated sludge accumulated at the bottom of the filter concentration tank 12 can be kept from the unconcentrated sludge. The sludge discharge pipe 67 discharges to the outside, and discharges only unconcentrated sludge to the outside. Moreover, when the generation|occurrence|production amount of concentrated sludge changes by the water quality change of raw water, you may switch over discharge valve 112a, 112b, and 112c. Thereby, it becomes possible to discharge only unconcentrated sludge to the outside regardless of a change in the sedimentation height of the concentrated sludge in the filter concentration tank 12 . For example, when the sedimentation height of the concentrated sludge becomes higher and is closest to the branch pipe 108b at the second height level from the bottom of the filter concentration tank 1, the outlet valves 112c and 112b of the branch pipe at the lowest height and the second height level closure. On the other hand, what is necessary is just to open the discharge valve 112a of the branch pipe of the 3rd height level. In addition, in this embodiment, the installation height of the lowest branch pipe 108c is located above the upper end of the mesh tray 82 .

In addition, the following embodiments can be given as other examples. As shown in FIG. 2D, the following device (down pipe) can be exemplified, that is, as the unconcentrated sludge discharge pipe 67, it is installed so as to extend downward from the upper opening of the filter concentration tank 12 in the filter concentration tank 12 so that The lower end portion of the unconcentrated sludge drain pipe 67 is at a predetermined height H above the bottom of the filter concentration tank 12 . By providing a plurality of downpipes and changing the height positions of the ends of the respective downpipes in the filtration concentration tank 12, it is also possible to have the same functions as the branch pipes 108a, 108b, and 108c described above. In addition, a suction pump 113 is provided on the non-thickened sludge drain pipe 67 . According to such an apparatus, the concentrated sludge accumulated at the bottom of the filter thickening tank 12 can be discharged outside from the unconcentrated sludge discharge pipe 67 , and only the unconcentrated sludge can be discharged outside by the suction pump 113 . In addition, the non-thickened sludge drainage pipe of such a down-pipe structure can be easily replaced in response to changes in the amount of thickened sludge generated due to changes in the quality of raw water. Thus, no matter how the sedimentation height of the concentrated sludge changes, the concentrated sludge accumulated at the bottom of the filter concentration tank 12 can not be discharged from the non-concentrated sludge discharge pipe 67 to the outside, but only the non-concentrated sludge can be discharged to the outside. discharge.

In addition, as another example, a flexible hose or the like may be provided. For example, as shown in FIG. 2E , a flexible hose 114 is communicably connected to the lower end of the unconcentrated sludge discharge pipe 67 . In addition, the vertical length of the flexible hose 114 can be adjusted so that the lower end of the unconcentrated sludge discharge pipe 67 becomes a predetermined height H above the bottom of the filter concentration tank 12 . More specifically, since the flexible hose 114 has a flexible serpentine portion, it is used by expanding and contracting the serpentine portion in the vertical direction. Thereby, the length of the flexible hose 114 in the vertical direction can be adjusted. In addition, a suction pump 113 is provided on the non-thickened sludge drain pipe 67 . According to the device having the above-mentioned structure, the concentrated sludge accumulated at the bottom of the filter concentration tank 12 is not discharged to the outside from the unconcentrated sludge discharge pipe 67, and only the unconcentrated sludge can be discharged to the outside by operating the suction pump 113. discharge. In addition, in response to changes in the amount of concentrated sludge produced due to changes in the quality of raw water, the serpentine portion of the flexible hose 114 provided at the lower end of the downpipe can be extended and contracted in the vertical direction, thereby adjusting Use the length side. Thereby, the unconcentrated sludge discharge pipe 67 itself does not need to be replaced, and only the unconcentrated sludge can be discharged to the outside regardless of changes in the sedimentation height of the concentrated sludge.

(operation method and function of suction filtration concentration device)

Next, the method of operation and the function of the suction filtration concentration device 10 having the above-mentioned structure will be described. In FIG. 7 , in the processing step of (A), first, the sludge X is supplied into the filter concentration tank 12 . Specifically, as shown in FIGS. 2A to 2F , the sludge supply/discharge valve 26 is opened to operate the sludge supply/discharge pump 28 . Then, through the sludge supply/discharge pipe 24 , the sludge to be filtered and concentrated is supplied into the filter concentration tank 12 up to the height of the top of the filter plate 14 . Then, preparations are performed for filtering and concentrating the sludge in the filter concentrating tank 12 by a siphon system. Specifically, the suction valve 33 is opened to operate the vacuum pump 35 . Accordingly, the liquid in the filter cloth 18 is sucked into the filtrate storage tank 36 through the distribution pipe 34 . In addition, corresponding to the height difference between the end of the distribution pipe 34 on the filter plate 14 side and the filtrate storage tank 36, a siphon effect can be used to pass the filtrate introduced into the filter chamber 76 through the sludge as shown in FIG. 6B. The discharge pipe 38 discharges to the outside.

Then, in the processing procedure of (B) shown in FIG. 7, the sludge in the filter concentration tank 12 is filter-concentrated. More specifically, as shown in FIGS. 2A to 2G , the sludge in the filter concentration tank 12 is attracted to the outer surface of the filter cloth 18 by the principle of siphon. At this time, the moisture in the sludge passes through the filter cloth 18 and is guided as a filtrate into the filter chamber 76 in the filter cloth 18 (see FIG. 6B ), thereby dehydrating the sludge. The dehydrated and concentrated sludge W adheres to the outer surface of the filter cloth 18 . At this time, the sludge can be attached to the outer surface of the filter cloth 18 with a desired adhesion force even with relatively low-pressure continuous suction by the siphon type. That is, adhesion can be performed with hardness and adhesion of the following degree: even if the agglomeration W of the concentrated sludge adhering to the outer surface of the filter cloth 18 is peeled off in the unconcentrated sludge, the concentrated sludge that can be used as an agglomerated sheet The degree of hardness and adhesion that maintains shape retention through mud.

In addition, tension is continuously applied from the periphery of the support plate 50 of the filter plate 14 by a coil spring 54 . Therefore, the support plate 50 of the filter plate 14 maintains a static state in which it does not move. Thereby, shaking or swinging of the filter plate 14 (support plate 50 ) can be prevented. Therefore, it is possible to prevent the concentrated sludge W attached to the outer surface of the filter cloth 18 from being peeled off from the outer surface of the filter cloth 18 before the concentrated sludge peeling step (or before peeling by the concentrated sludge peeling unit). Condition.

Then, in the processing step of (C) shown in FIG. 7 , the concentrated sludge W adhering to the filter cloth 18 is peeled off by expanding the filter cloth 18 . When this process is performed, the non-concentrated sludge in the filter thickening tank 12 also remains in a residual state. Specifically, as shown in FIGS. 2A to 2G and FIG. 3, the water inflow valve 44 is opened, and the water is sent to the filter chamber of the filter plate 14 from the liquid delivery pump 46 through the water inflow pipe 42, the distribution pipe 34 and the horizontal pipe 15. 76 transport (refer to Figure 6A). That is, water is continuously pressure-fed to the filter cloth 18 for a predetermined period of time from the side opposite to the surface to which the concentrated sludge adhered in the non-concentrated sludge after filtering and concentrating. At this time, the pressure-fed water will flow out into the unconcentrated sludge through a large number of pores of the filter cloth 18 . On the other hand, the concentrated sludge adheres to the entire outer surface of the filter cloth 18 and clogs many fine pores of the filter cloth 18 . In addition, the hydraulic pressure of the non-concentrated sludge is similarly received on the outer surface of the filter cloth 18 to which the concentrated sludge adhered. Therefore, the hydraulic pressure of the water pumped into the filter chamber 76 presses the concentrated sludge adhering to the outer surface of the filter cloth 18 into the non-concentrated sludge until at least overcoming the hydraulic pressure of the non-concentrated sludge. That is, the concentrated sludge will not be peeled off from the surface of the filter cloth 18 until at least the hydraulic pressure of the unconcentrated sludge is overcome. Therefore, the pressure of the pressure-fed water in the filter chamber 76 rises, and at the same time, the filter cloth 18 is expanded.

In other words, when the concentrated sludge adheres to the entire outer surface of the filter cloth 18 and clogs a large number of pores of the filter cloth 18 , the expansion of the filter cloth 18 proceeds until the hydraulic pressure of the pressure-fed water is reduced in the filter chamber 76 . Similarly, until the specified pressure is reached. Then, when the water pressure of the pressure-fed water reaches a predetermined pressure in the filter chamber 76 similarly, the expansion of the filter cloth 18 is completed. That is, the pressure-fed water can press the concentrated sludge adhering to the outer surface of the filter cloth 18 into the unconcentrated sludge all at once over the entire filter cloth 18 .

As described above, the concentrated sludge W can be uniformly peeled off from the outer surface of the filter cloth 18 in the circumferential direction as shown in FIG. 11A . In addition, as shown in FIG. 11B , the concentrated sludge W can be uniformly peeled off from the outer surface of the filter cloth 18 in the height direction.

In addition, when peeling the concentrated sludge attached to the outer surface of the filter cloth 18 from the filter cloth 18, by using water in the unconcentrated sludge to peel off, the noise associated with the peeling can be reduced, and the need for suction filtration can be eliminated. Restrictions on the installation place of the enrichment device.

In addition, since the concentrated sludge can be peeled off in a state of hardness, size, and shape retention to the extent that it will not be redissolved, the concentrated sludge of the agglomerated sheet is subjected to buoyancy in the unconcentrated sludge. One side falls to the bottom of the filter concentration tank 12. Thereby, the impact at the time of collision with the bottom can be alleviated. Moreover, since the thickened sludge of agglomerated form is relatively hard, it can prevent that the concentration degree of a thickened sludge falls by dissolving a thickened sludge into an unconcentrated sludge. In addition, since the concentrated sludge in the form of agglomerates has shape retention properties, the agglomerates are not broken into layers. Therefore, from the mesh tray 82 positioned at the bottom of the filter concentration tank 12, the state of the concentrated sludge of the agglomerated sheet, or the state of maintaining the agglomerated form to the extent that it is easy to discharge, can be easily and efficiently released to the outside. discharge.

Then, in the processing step (D) shown in FIG. 7 , the peeled concentrated sludge W is discharged to the outside of the filter concentration tank 12 . For example, in the case where the concentrated sludge discharge unit is the concentrated sludge removal unit 23 shown in FIG. 2F and FIG. 12 Take it out to the outside. In addition, in this step, the non-thickened sludge in the filtration thickening tank 12 remains in a residual state. Then, the operator lifts the mesh tray 82 by grasping the handle, and scoops out the concentrated sludge of agglomerated pieces accumulated in the mesh tray 82 and discharges them to the outside. Since the thickened sludge has hardness, size, and shape retention that cannot be redissolved, it can maintain the shape retention as an agglomerated piece in the non-thickened sludge after peeling until it is taken out. Therefore, according to the above structure, it is not necessary to discharge the non-concentrated sludge to the outside before discharging the concentrated sludge, and solid-liquid separation can be easily performed in the non-concentrated sludge. That is, continuous processing is possible. So far, the sludge filtration and concentration operation is completed. In addition, the concentrated sludge discharged to the outside of the filter concentration tank 12 is further concentrated by a separate dehydrator, formed into lumps again, and then incinerated or landfilled.

In the present invention, it is preferable to perform the concentrated sludge discharge step after repeating the cycle consisting of the above-mentioned filtration concentration step and the above-mentioned concentrated sludge stripping step for a predetermined number of times, and there is a step of passing sludge before the above-mentioned filtration concentration step in each cycle. Sludge supply step is a step of supplying sludge into the filtration thickening tank 12 . In order to realize the above-mentioned concentrated sludge discharge step, for example, as shown in FIG. 9A , there may be a step of replenishing (supplying) new sludge into the filter concentration tank 12 . Specifically, as shown in FIG. 9A , unconcentrated sludge is supplied into the filter concentration tank 12 , and the filter concentration is performed in the filter concentration tank 12 , and the concentrated sludge is peeled off. Then, the separated concentrated sludge is discharged to the outside, and after the concentrated sludge is discharged to the outside, new sludge may be supplied (recharged) into the filter concentration tank 12 . Alternatively, as shown in FIG. 9A , a cycle consisting of a filtration concentration step and a concentrated sludge stripping step is repeated a predetermined number of times. Moreover, you may supply new sludge in the filter concentration tank 12 by the sludge supply process before the filter concentration process in each cycle. In addition, what is necessary is just to determine suitably about the number of times of circulation considering the filtration ability of the filter plate 14, the amount of sludge to be processed, etc. Thereby, the filtration concentration process of sludge can be performed more efficiently.

In addition, it is preferable that the above-mentioned concentrated sludge discharge step is performed in parallel with the above-mentioned filter concentration step, and on the other hand, there is a step of replenishing sludge into the filter concentration tank 12 by the above-mentioned sludge supply step before the above-mentioned filter concentration step. In order to realize the above-mentioned concentrated sludge discharge step, for example, as shown in Fig. 8 and Fig. 9B, it is also possible to discharge the concentrated sludge of the stripped agglomerated sheet to the outside, while new sludge is discharged into the filter concentration tank 12. At the same time as the replenishment (supply) step, filter concentration is performed. Specifically, it can be applied when there is room in the filter concentration tank 12 and it is not necessary to temporarily take out the filter plate 14 to the outside in order to discharge the concentrated sludge to the outside. In addition, it can be applied when arranging and using multiple sets of bucket conveyors or belt conveyors along the bottom and side walls of the filtration concentration tank 12 . Thereby, the filtration concentration process of sludge can be performed more efficiently.

As mentioned above, although embodiment of this invention was described in detail, those skilled in the art can make various corrections and deformation|transformation in the range which does not deviate from the range of this invention. For example, in this embodiment, although the case where the object of filtration concentration was sludge was demonstrated, it is not limited to this. For example, incineration ash contained in an alkaline solution, foreign matter contained in beverage liquids such as milk and fruit juice, and turbid matter contained in turbid water may be mentioned as objects of filtration concentration. As long as conditions such as the type of filter cloth 18, the size of the pore diameter, and the suction force are appropriately set corresponding to the above-mentioned filtration and concentration objects, the suction filtration concentration method and the suction filtration concentration device involved in the present invention can also be aimed at use them.

Example

In order to confirm the effect of the present invention, the present inventors used the sludge of a water purification plant as the object of filtration and concentration, carried out a siphonic suction filtration concentration test using filter cloth, and used the peeling pressure obtained as the water of the peeling medium as a parameter to determine the effect of the peeling on the sludge. The relationship between time and peeling rate was investigated.

Fig. 12 shows the whole of the test device. Since the basic structure is the same as that of FIG. 2A after removing the concentrated sludge removal part 23 (mesh tray 82), its detailed description is omitted, but the water inflow pipe 42 is connected to an inverted U-shaped pipe that communicates with the filter chamber 76 at one end. In the middle of the process, a peeling pressure regulating valve 150 is provided on the water inflow pipe 42, and by adjusting the opening of the peeling pressure regulating valve 150, the pressure of water and the supply time are adjusted. Specifically, the washing water is supplied from the washing water tank 162 to the filter chamber 76 formed inside the filter plate 14 through the water inflow pipe 42 and the distribution pipe 34 by the washing water pump 160 . Moreover, the raw liquid which is the sludge of a water purification plant is supplied from the raw liquid tank 152 to the filter concentration tank 12 by the raw liquid pump 154. The sludge is continuously sucked by the suction pipe 31 , the filtrate F is discharged to the external filtrate tank 36 through the filtrate discharge pipe 38 , and the concentrated sludge W adheres to the outer surface of the filter cloth 18 . The concentrated sludge accumulated at the bottom of the filter concentration tank 12 is discharged to an external filter concentration tank 158 by a concentrated sludge discharge pump 156 . In addition, 164 denotes a washing water pressure adjusting valve, 166 denotes a compressor, and 168 denotes a raw liquid discharge pump. In addition, the specifications of the filter plate 14 are as follows.

(1) Material: filter cloth 18··nylon, support plate 50··resin

(2) Number of pieces: 1 piece

(3) Size: 1900mm×2500mm, filter area: 9.5m ²

(4) Manufacturing method: sewing the filter cloth 18 and the support plate 50 together

(5) Filter plate volume: 0.07m ³ (thickness 15mm)

(6) Composition of sludge: Ig.loss: 36.4%, SiO ₂ : 34.2%, Al ₂ O ₃ : 18.7%, Fe ₂ O ₃ : 4.1%, CaO: 1.4%, SO ₄ : 1.8%, others: 3.4% (Also, % means mass%)

(7) Filtration time: 90 minutes

Fig. 13 shows the relationship between the peeling time and the peeling rate. As shown in FIG. 13 , if the peeling pressure is constant, the peeling rate increases as the peeling time increases. It can be seen that in order to secure a peeling rate of 95% or more for practical use, at least 30 seconds is required as a continuous peeling time regardless of the peeling pressure.

Industrial Applicability

The suction filtration concentration method and the suction filtration concentration device involved in the present invention are not limited to the technical field of water treatment including upper water, reclaimed water and sewage, and can also be applied to a wide range of food fields, chemical industry fields, etc. Among them, it is particularly useful for a suction filtration thickening device used in a thickening step of sludge generated in a water treatment step of a water purification plant or the like.

Claims (10)

1. A suction filtration concentration method, which makes the sludge pass through the filter cloth in the filter concentration tank for suction filtration, so that the filtrate is recovered through the filter chamber inside the filter cloth, and the sludge is attached as concentrated sludge On the outer surface of the filter cloth, The method has the following steps: a sludge supply step of supplying sludge into the filter thickening tank; a filter concentration step in which the supplied sludge is subjected to filter concentration in a filter concentration tank; Thickened sludge stripping step, in this step, the thickened sludge after filtration and concentration is stripped from the outer surface of the filter cloth; and a concentrated sludge discharge step in which the stripped concentrated sludge is discharged to the outside of the filter concentration tank, The filtration concentration step has a step of continuously sucking the concentrated sludge to adhere to it by using a predetermined suction pressure to the extent that the shape retention can be maintained even if the concentrated sludge is separated from the unconcentrated sludge. On the outer surface of the filter cloth, The concentrated sludge stripping step has a step of continuously pressure-feeding water to the filter cloth through the filter chamber for a predetermined time in the supplied unconcentrated sludge, thereby attaching the sludge to the outer surface of the filter cloth. The concentrated sludge is stripped of the filter residue. 2. suction filtration concentration method according to claim 1, wherein, The said thickened sludge discharge process has the process of taking out the thickened sludge of agglomerated sheet accumulated in the bottom of a filtration thickening tank from non-thickened sludge. 3. suction filtration concentration method according to claim 1 or 2, wherein, The step of discharging the thickened sludge is performed after a cycle consisting of the step of filtering and thickening and the step of stripping the thickened sludge is repeated a predetermined number of times, and before the step of filtering and thickening in each cycle, there is a function of using the Sludge supply step is a step of supplying sludge into the filter thickening tank. 4. suction filtration concentration method according to claim 1 or 2, wherein, The concentrated sludge discharge step is performed in parallel with the filtration concentration step, and before the filtration concentration step, there is a step of replenishing sludge into the filtration concentration tank in the sludge supply step. 5. The suction filtration concentration method according to any one of claims 1 to 4, wherein, The water pressure-fed into the filter chamber in the concentrated sludge stripping step utilizes the filtrate recovered in the filter chamber. 6. A suction filtration concentration device, which makes the sludge pass through the filter cloth for suction filtration, so that the filtrate is recovered through the filter chamber inside the filter cloth, and the sludge is attached to the outside of the filter cloth as concentrated sludge on the surface, The suction filtration concentration device has: A sludge supply unit that supplies sludge to the filter thickening tank; A filter concentration unit that performs filter concentration on the supplied sludge in the filter concentration tank; a concentrated sludge stripping unit, which strips the filtered and concentrated concentrated sludge from the outer surface of the filter cloth; and a concentrated sludge discharge unit that discharges the stripped concentrated sludge to the outside of the filter concentration tank, The filter concentration unit has a unit that continuously sucks the concentrated sludge to adhere to it by using a predetermined suction pressure to maintain shape retention even if the concentrated sludge is peeled off from the unconcentrated sludge. On the outer surface of the filter cloth, The concentrated sludge stripping unit has a unit for continuously pressure-feeding water to the filter cloth for a predetermined time through the filter chamber among the supplied unconcentrated sludge, thereby removing the sludge adhering to the outer surface of the filter cloth. Thickened sludge is stripped of filter residue. 7. suction filtration concentration device according to claim 6, wherein, The said thickened sludge discharge means has the means which pulls out the thickened sludge of agglomerated sheet accumulated in the bottom of a filtration thickening tank from non-thickened sludge. 8. suction filtration concentration device according to claim 6, wherein, The thickened sludge discharge unit is a mesh tray with a handle disposed on the bottom of the filter thickening tank, and the handle has a length extending upward from the upper opening of the filter thickening tank. 9. suction filtration concentration device according to claim 6, wherein, The concentrated sludge discharge unit is a bucket conveyor extending outward from the bottom of the filter concentration tank through the upper opening of the filter concentration tank, and the conveyor surface moving from the bottom of the filter concentration tank to the outside Configured facing upwards. 10. suction filtration concentration device according to claim 6, wherein, A plurality of water supply pipes communicate with the filter chamber at heights different from each other in the height direction of the filter cloth.

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