JP2005218888A - Sludge dehydrator and sludge dehydration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sludge dehydrator which can effectively use separated liquid, separated by a first dehydration part, in a sludge dehydration process. <P>SOLUTION: The sludge dehydrator comprises the first dehydration part 3 and a second dehydration part 4 for further dehydrating sludge dehydrated in the first dehydration part 3, and the separated liquid W separated in the first dehydration part 3 is supplied onto a water-permeable filtration chamber 12 of the second dehydration part 4. Thereby the outer surface of the water-permeable filtration chamber 12 is always washed with the separated liquid W during dehydration operation to prevent the clogging and the like of the water-permeable filtration chamber 12. Preferably a water-permeable filtration chamber 6 of the first dehydration part 3 is disposed just above the water-permeable filtration chamber 12 of the second dehydration part 4, which dispenses with a special means for supplying the separated liquid W to the second dehydration part 4, and enables the saving of an installation area for the whole sludge dehydrator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sludge dewatering device and a sludge dewatering method.

As a device for dewatering sludge discharged from sewage treatment plants, manure treatment plants, paper mills, etc., conventionally, a gravity-type preconcentration unit for preconcentrating (preliminary dewatering) sludge added with a flocculant; There is known a dehydrating apparatus including a dewatering unit such as a compression type that dehydrates concentrated sludge concentrated in a preconcentrating unit (see Patent Document 1).
Japanese Patent No. 3222278 (see in particular paragraph 0013 and FIG. 1)

  Although not explicitly stated in Patent Document 1, conventionally, the separated liquid separated in the preliminary concentrating section is usually drained out of the apparatus as it is or after being subjected to a predetermined treatment. There are no proposals to make effective use of this for the purpose of smoothing sludge dehydration.

  In addition, according to the dewatering apparatus, even if the sludge properties change or difference, even if the added flocculant does not exhibit a sufficient sludge agglomeration effect, after being concentrated in the preliminary concentration unit However, since all of the concentrated sludge is supplied to the dewatering unit as it is, there is a problem that a target dewatering rate cannot be obtained in the dewatering unit.

  The present invention has been made in view of the above circumstances, and in a sludge dewatering device including a first dewatering unit and a second dewatering unit, a separated liquid separated by the first dewatering unit. The present invention intends to provide a sludge dewatering device and a sludge dewatering method that can effectively utilize the above.

  Another object of the present invention is to provide a sludge dewatering device in which the dewatering rate does not decrease even when the sludge aggregation state is poor.

  In order to solve the above problems, a sludge dewatering apparatus according to the present invention includes a first dewatering unit and a second dewatering unit, and the separated liquid separated in the first dewatering unit is the second dewatering unit. It is made to supply on the water-permeable filtration chamber of a dehydration part (Claim 1).

  According to the present invention, since the separation liquid separated in the first dehydration unit is supplied onto the water filtration chamber of the second dehydration unit, the water filtration chamber is always used during the dehydration operation. The outer surface is washed with the separation liquid, so that the separation liquid in the first dehydrating part is effectively utilized and the water-permeable filtration chamber is prevented from being clogged.

  As a preferred embodiment, the second dewatering part may be a dewatering part for further dewatering the sludge dewatered in the first dewatering part (Claim 2). In this case, in a series of dehydration processing steps from the first dehydration unit to the second dehydration unit, the separation liquid from the first dehydration unit is washed in the second dehydration unit as a post-process unit. Therefore, the separation liquid generated in the series of dehydration processes can be effectively used in the series of dehydration processes.

  The separation liquid in the first dehydration unit can be supplied to the second dehydration unit through a pipe, a guide groove, or the like extending from the first dehydration unit to the second dehydration unit. However, as a preferred embodiment, the water-permeable filtration chamber of the first dewatering unit may be disposed directly above the water-permeable filtration chamber of the second dehydration unit (Claims). 3). In this way, the water filtration chamber of the second dehydrating unit can be washed by allowing the separated liquid separated in the first dehydrating unit to flow down to the second dehydrating unit as it is. Therefore, a special means for supplying the separation liquid to the second dehydrating unit is unnecessary, which is preferable. Moreover, since the outlines of the two water-permeable filtration chambers overlap each other when viewed from above, there is an advantage that the installation area of the entire sludge dewatering device can be saved.

  As a preferred embodiment, a sludge passage for communicating the first dewatering part and the second dewatering part extends downward from the first dewatering part to the second dewatering part. The second dewatering part may be expanded as it approaches (Claim 4). In this way, it is preferable that the sludge supplied to the second dewatering unit is prevented from being clogged in the sludge passage.

  As a preferred embodiment, a sludge passage that allows the first dewatering part and the second dewatering part to communicate with each other, a sludge passage state that allows the sludge to pass to the second dewatering part, and the first It is also possible to provide a mud supply control mechanism capable of switching between a sludge state in which sludge is prevented from passing to the second dewatering section and discharged to the outside (Claim 5). In this way, for example, the sludge is supplied from the first dewatering section to the second dewatering section as it is because the sludge is not sufficiently dehydrated and aggregated in the first dewatering section. Is inappropriate, the mud supply control mechanism is operated to switch the sludge passage from the mud passage state to the exhaust mud state, thereby preventing mud supply to the second dewatering unit. Can be discharged to the outside. And the fall of a dehydration rate can be prevented by adding the suitable coagulant | flocculant according to the property of sludge, for example, and supplying it to said 1st dehydration part again.

  As one preferred embodiment, the mud supply control mechanism includes a sludge passage position that defines the sludge passage, and a sludge that extends across the sludge passage and guides the sludge to the outside of the sludge passage. It is freely displaceable between the position changeable flow path changing flap, the mud passage position to close the mud outlet and the sludge passage to open, and the mud position to open the mud opening. It is also possible to provide a flap for opening and closing the mud discharge port (claim 6). In this case, when the flaps are held in the mud posture, the sludge passage is in a mud passage state, and when the flaps are held in the mud posture, the sludge passage is in a mud state.

  The sludge dewatering method according to the present invention is a sludge dewatering method in which the sludge dehydrated in the first dewatering section is further dewatered in the second dewatering section, and the separated liquid separated in the first dewatering section It is used as a cleaning liquid for the second dehydration part (claim 7).

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic view of a sludge dewatering apparatus according to an embodiment of the present invention.

  The sludge dewatering device 1 according to the present embodiment includes a sludge aggregation treatment unit 2, a preconcentration unit (preliminary dehydration unit) 3 as a first dehydration unit, a main dehydration unit 4 as a second dehydration unit, It has. The raw mud (sludge) as a treatment target is first added with a flocculant in the sludge agglomeration processing unit 2 to be coarse granular agglomerated sludge, and then subjected to a preliminary dehydration action in the preconcentration unit 3. The concentrated sludge is finally transferred to the main dewatering unit 4 and further dewatered.

  In the present embodiment, the pre-concentration unit 3 is disposed directly above the main dehydrating unit 4 that requires the largest installation area, thereby saving the installation area of the entire dehydrating device.

  In the sludge agglomeration processing unit 2, a flocculant is added to the raw mud and stirred. As the flocculant, an appropriate one according to the properties of the raw mud is selected and used. The specific configuration of the sludge aggregation processing unit 2 is not limited. For example, as in the present embodiment, a screw conveyor type driven by a motor 5 or the like as a drive source, or a stirring blade is used. Etc. can be adopted.

  The sludge agglomerated in the sludge agglomeration processing unit 2 is supplied to the preconcentration unit 3 and subjected to a preconcentration treatment by an appropriate method. In the present embodiment, the preliminary concentration unit 3 performs a dehydration process by gravity.

  That is, the pre-concentration unit 3 includes a horizontal cylindrical pre-concentration filtration chamber (pre-concentration water-filtration chamber) 6 whose peripheral wall is made of a water-permeable porous plate such as punching metal, and the pre-concentration filtration chamber 6. And a screw conveyor 7 disposed concentrically. The preconcentration filtration chamber 6 has a coagulated sludge inlet 8 for receiving the coagulated sludge at the end on the sludge coagulation treatment unit 2 side, and a concentrated sludge outlet 9 at the opposite end. Yes. The screw conveyor 7 is rotationally driven using a motor 10 or the like as a drive source, and conveys the aggregated sludge supplied from the aggregated sludge inlet 8 toward the concentrated sludge outlet 9, and in this conveyance process, the aggregated sludge is converted into the aggregated sludge. A pre-concentration process or a pre-dehydration process is performed. The separation liquid (water) W by dehydration flows down from the mesh of the preconcentration filtration chamber 6 and is used as a cleaning liquid for the main dehydration unit 4 as described later.

  The sludge pre-concentrated in the pre-concentration unit 3 is supplied to the main dehydration unit 4 through a sludge passage 11 extending in the vertical direction, and is subjected to further dehydration treatment by an appropriate method. In the present embodiment, the main dewatering unit 4 performs a dewatering process by pressing.

  That is, the main dehydrating section 4 includes a horizontal cylindrical main dewatering filtration chamber (main dewatering water-permeable filtration chamber) 12 whose peripheral wall is made of a water-permeable porous plate such as a punching metal, and the inside of the main dehydration filtration chamber 12. And a screw 13 disposed concentrically. The main dewatering filtration chamber 12 is provided with a concentrated sludge inlet 14 for receiving the concentrated sludge from the preliminary concentrating unit 3 at the upper end of the outer peripheral surface of the preconcentrating unit 3 side, on the opposite side. A dewatering cake outlet 15 is provided at the end. The concentrated sludge inlet 14 communicates with the concentrated sludge outlet 9 of the preconcentration filtration chamber 3 through the sludge passage 11.

  The screw 13 includes a tapered body 16 that gradually increases in diameter from the concentrated sludge inlet 14 side to the dehydrated cake outlet 15 side of the main dewatering filtration chamber 12, and on the outer periphery of the tapered body 16. A screw blade 17 having a uniform outer diameter that matches the inner diameter of the main dehydration filtration chamber 12 is formed. The screw 13 is rotationally driven using a motor 18 or the like as a drive source, and conveys the concentrated sludge supplied from the concentrated sludge inlet 14 toward the dehydrated cake outlet 15. An annular dewatering space 19 between the outer peripheral surface of the screw 13 and the inner peripheral surface of the main dewatering filtration chamber 6 is gradually narrowed toward the dewatering cake outlet 15. Accordingly, the concentrated sludge is gradually subjected to a large pressing action in the process of transporting toward the dehydrated cake outlet 15 to squeeze out moisture. The separation liquid (water) by dehydration flows down from the mesh of the main dehydration filtration chamber 12.

  In the present embodiment, the separation liquid W separated by the preliminary concentration unit 3 is supplied onto the main dehydration filtration chamber 12 of the main dehydration unit 4. For this reason, the outer surface of the main dehydration filtration chamber 12 is always washed with the separation liquid W during the dehydration operation, and the separation liquid W in the preliminary concentration unit 3 is effectively utilized, The main dehydration filtration chamber 12 is prevented from being clogged. In particular, in the present embodiment, the preconcentration filtration chamber 6 is disposed directly above the main dehydration filtration chamber 12, so that the preconcentration filtration chamber 6 is dehydrated and dehydrated. The separation liquid W flowing down from the liquid falls on the main dehydration filtration chamber 12 as it is without requiring any special piping or guide members. For this reason, the structure of a dehydrating apparatus becomes simple and suitable.

  The sludge dewatering apparatus 1 is configured to allow the sludge passage 11 to pass through the sludge passage 11 from the preconcentration unit 3 to the dehydration unit 3, and from the preconcentration unit 3 to the dehydration unit 4. A mud supply control mechanism 20 is provided that can be switched to a mud state in which the concentrated sludge is prevented from passing and discharged to the outside. The mud supply control mechanism 20 is used when the state of sludge aggregation in the preliminary concentration unit 3 is poor.

  That is, since the coagulation state of sludge can be determined visually by the preliminary concentration unit 3, when the coagulation effect by the added coagulant is not sufficiently exhibited, the mud supply control mechanism 20 is operated, By switching the sludge passage 11 from the mud passage state to the waste mud state, the sludge is taken out of the apparatus before the dewatering unit 4. Thereby, the fall of the dehydration rate in the said dehydration part 4 can be prevented. The sludge taken out to the outside is re-introduced into the agglomeration processing unit 2, and the flocculant to be added is changed to an appropriate type according to the properties of the sludge and supplied again to the preconcentration unit 3. Can do.

  In the present embodiment, the mud supply control mechanism 20 is configured by a combination of a flow path changing flap 21 and a drainage port opening / closing flap 22. Both the flaps 21 and 22 constitute a part of the passage defining cylinder 23 that defines the sludge passage 11, and the lower end side is swingable about the pivot shaft of the upper end portion. The flow path changing flap 21 extends obliquely so as to cross the sludge passage 11 and a posture during mud passage (shown by a solid line in FIG. 1) extending along the outer surface of the passage defining cylinder 23. The sludge can be displaced to a sludge posture (shown in phantom lines in FIG. 1) for guiding the sludge to the outside of the sludge passage 11. Likewise, the flap 22 for opening / closing the mud port opens the mud port 24 (shown by a solid line in FIG. 1) that closes the mud port 24 formed in the passage defining cylinder 23, and the mud port 24. It is freely displaceable in the mud draining posture (shown in phantom lines in FIG. 1). When the flaps 21 and 22 are held in the mud passage position, the sludge passage 11 is in a mud passage state. When the flaps 21 and 22 are held in the mud discharge position, the sludge passage 11 is discharged. It becomes mud.

  In addition, both the flaps 21 and 22 may be manually operated to change their posture, or may be driven by power by providing appropriate actuators. In addition, the flaps 21 and 22 are connected to each other by an appropriate connecting member (not shown), and the posture change operation of the flaps 21 and 22 to the posture during mud and the posture during mud discharge is performed. It is preferable that the operations are performed in conjunction with each other.

  As shown in FIG. 2 which is a view taken in the direction of arrow II in FIG. 1, the passage defining cylinder 23 that defines the sludge passage 11 expands from the preconcentration unit 3 side toward the dehydration unit 4 side. It is desirable to have it. In this way, it is possible to prevent the sludge concentrated in the preliminary concentration unit 3 from being clogged in the sludge passage 11, which is more preferable.

It is the schematic of the sludge dehydration apparatus which concerns on one embodiment of this invention. It is II arrow directional view of FIG.

Explanation of symbols

3 Pre-concentration part (first dehydration part)
4 Main dehydration part (second dehydration part)
6 Water-permeable filtration chamber (preconcentration filtration chamber)
11 Sludge passage 12 Water-permeable filtration chamber (main dehydration filtration chamber)
20 Mud supply control mechanism 21 Flap for channel change 22 Flap for opening / closing mud outlet 24 Drain port W Separation liquid in preconcentration section

Claims (7)

  A first dehydrating unit and a second dehydrating unit, wherein the separated liquid separated in the first dehydrating unit is supplied onto the water-permeable filtration chamber of the second dehydrating unit. Become a sludge dewatering device.   The sludge dewatering device according to claim 1, wherein the second dewatering unit is a dewatering unit that further dewaters the sludge dewatered in the first dewatering unit.   The sludge dewatering device according to claim 1 or 2, wherein the water-permeable filtration chamber of the first dewatering unit is disposed immediately above the water-permeable filtration chamber of the second dewatering unit.   A sludge passage that allows the first dewatering unit and the second dewatering unit to communicate with each other extends downward from the first dewatering unit to the second dewatering unit. The sludge dewatering device according to claim 2 or 3, wherein the sludge dewatering device expands as it approaches.   A sludge passage that allows the first dewatering unit and the second dewatering unit to communicate with each other; a mud passing state that allows the sludge to pass to the second dewatering unit; and the sludge to the second dewatering unit. The sludge dewatering device according to claim 2, 3 or 4, further comprising a mud supply control mechanism that can be switched between a mud discharge state that blocks passage and is discharged to the outside.   The mud supply control mechanism is freely displaceable between a mud posture that defines the sludge passage and a drainage posture that extends across the sludge passage and guides the sludge to the outside of the sludge passage. A flap for changing the flow path, a mud posture that closes the mud port and defines the sludge passage, and a mud port opening / closing flap that is displaceable to the mud posture that opens the mud port, The sludge dewatering device according to claim 5.   A sludge dewatering method in which the sludge dehydrated in the first dewatering section is further dewatered in the second dewatering section, and the separated liquid separated in the first dewatering section is used as a cleaning liquid for the second dewatering section. A sludge dewatering method characterized by

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