JP2015024371A - Extraction equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide extraction equipment continuously separating and recovering a specified stock from sludge generated in a sewage treatment process.SOLUTION: Provided is extraction equipment including: a grinding machine of sub-dividing sludge; a separation machine of separating a hardly-decomposable organic matter and an easily-decomposable organic matter from the ground prepared sludge; and a recovery device of extracting a hardly-decomposable organic matter, in which a prescribed hardly-decomposable organic matter is continuously separated and recovered, where only the one useful as a dewatering aid from sludge made to flow into a sewage disposal plant is selectively recovered, and it can be effectively utilized for the dewatering of hardly-dewatered sludge in the latter stage.

Description

The present invention relates to an apparatus for separating and collecting a specific material from sludge and selecting and separating and collecting only a suitable fibrous material as a dehydrating aid from sludge flowing into a sewage treatment plant.

Conventionally, hardly dewatered sludge generated in a sewage treatment plant has poor dewaterability. In the sludge treatment, sludge (hardly dewatered sludge) obtained by decomposing organic matter (fiber content, etc.) in the sludge by the action of bacteria is dehydrated. Therefore, fiber content is reduced in the sludge before dehydration. Since the fiber content in the sludge functions as the core of aggregation, the sludge in which the fiber content is reduced cannot perform proper aggregation, resulting in poor dewaterability.

A method of dehydrating by mixing a fiber material or a plant material such as sawdust or rice husk as a dehydrating aid with a hardly dehydrated sludge has been known for a long time and has been practiced in many treatment plants. When a fibrous material is used as a dehydration aid, a dehydrated cake having a low water content can be obtained, and in the case of pressure dehydration, the peelability of the dehydrated cake is improved. However, since a large amount of dehydration aid has to be prepared and supplied, running costs have increased, and there has been a problem that storage and supply facilities for the dehydration aid have to be installed.

Therefore, a technique for separating and collecting the fiber content in raw sludge generated from the first sedimentation basin of the sludge treatment process and adding the fiber content to hardly dewatered sludge such as excess sludge or digested sludge is disclosed in Citation 1.

In the cited document 2, different components of the multi-layer material are crushed into small pieces with a counter-rotating opposing disk, and a material that can be pulped with an open drum is separated from one end of the drum by a screw feeder in a subsequent drum. A collection device for discharging the remaining small pieces is disclosed.

JP-A 61-268400 Special Table 2000-513267

Since the technology of the cited document 1 collects the fiber from the sludge in the treatment plant, it is not necessary to prepare a dehydration aid separately, and the running cost and equipment are the same as those in normal treatment. However, as disclosed in the specification, in a separation apparatus using a screen or a vibrating screen mesh, as a dehydration aid for easily degradable organic substances derived from food residues entangled with fiber components (persistent organic substances) Inappropriate things cannot be separated and collected together with the fiber content. Therefore, when fibers entangled with easily decomposable organic substances, most of which are moisture, are added as a dehydration aid, the moisture content of the dehydrated cake increases and the processing cost increases. Since the readily decomposable organic matter rots, the dehydration aid before addition and the dehydrated cake after addition cannot be stored for a long period of time. Since a specific method for recovering only the fiber component effective as a dehydrating aid has not been disclosed, it has been difficult to recover only the necessary fiber component.

The technique of Cited Document 2 collects various components in a multilayer material composed of paper, plastic, and aluminum foil. Paper fibers that can be pulped (muddy) and solids such as aluminum and plastic that cannot be pulped. Is a device for separating and recovering. The rotating disk in the previous stage has not only the action of crushing the multilayer structure into small pieces, but also the action of pumping the small pieces together with the suspension to the separator. The object to be treated of the present invention is to subdivide while crushing organic substances derived from extremely small food residues entangled with fibers in sewage, so it is necessary to set the gap between the disks extremely narrow, The pump cannot be transferred to the separator.

In the latter porous drum, the paper fibers loosened and dispersed in the suspension are separated from the drum outside the drum, and the remaining small pieces (aluminum, plastic, etc.) in the drum are conveyed to the other end and discharged. This is established because there are small pieces (aluminum, plastic, etc.) having a certain size that does not become mud when immersed in the suspension. In this technique, it is difficult to separate the fiber and the easily decomposable organic matter from the fiber contained in the sludge of the sewage treatment plant and the fine easily decomposable organic matter derived from the food residue entangled with the fiber. Moreover, when using a fiber part as a dehydration auxiliary agent, the process of extracting only a fiber part from suspension is needed separately.

The present invention relates to an extraction apparatus that selectively separates and recovers only a fiber having a predetermined property useful as a dehydration aid when dewatering sludge from sludge flowing into a sewage treatment plant.

The extraction apparatus of the present invention is an apparatus for extracting a specific material from sludge generated in a sewage treatment process, and a pulverizer that subdivides sludge and a hardly decomposable organic substance and an easily decomposable organic substance separated from the ground prepared sludge. And a recovery device that extracts persistent organic substances, and separates and recovers predetermined persistent organic substances continuously. Only those that are useful as dehydration aids from sludge flowing into the sewage treatment plant It can be selectively collected and used effectively for the dewatering of difficult-to-dehydrate sludge in the later stage.

A separation tank that collects readily degradable organic substances is provided below the separator, and a return pipe that returns the easily degradable organic substances to the biological treatment tank of the sewage treatment plant is connected to the separation tank. The reaction period can be shortened and it contributes to the improvement of the processing efficiency of the whole treatment plant.

When the grinding machine is configured with a rotating disk and a fixed disk facing each other, a supply pipe is connected to a supply port opened at the center of the rotating disk, and a predetermined gap is provided at the outer peripheral end of the facing disk, Sludge can be subdivided and materials useful as dehydration aids can be extracted from readily decomposable organic substances.

Further, the crusher is configured by inserting a cylindrical screen into a cylindrical casing closed on one side, and rotatably installing a sliding contact member that is in sliding contact with the inner wall of the cylindrical screen, and at the center of the opening of the cylindrical screen. In addition, a supply pipe and a transfer pipe may be provided in the casing.

When the separator is configured with a cylindrical screen that is rotatably arranged, and the recovery device is configured with screw blades hung around in the screen, it separates persistent organic substances continuously. Can be recovered. When the vicinity of the extraction part of the separator is gradually reduced in a conical shape, the effect of gravity separation into the separation tank together with water can be enhanced with respect to slight impurities adhering to the inside of the fibers or small fibers below the recovery range.

Further, the separator may be wound around a plurality of rolls so as to run freely, and may be configured as an endless belt having a large number of pores, and the recovery device may be configured by a scraper disposed behind the filtration surface.

When the filtration surface including the supply part of the separator is immersed in the separation tank by storing immersion water, each material entangled in the separation step is dispersed while being dispersed, so that the separation effect is improved. You may isolate | separate, providing the injection apparatus which injects the filtration surface of a separator with high pressure water, and injecting high pressure water.

A material in the separation process is provided with a rolling element tank that mixes a plurality of rolling elements in the separator and collects the rolling elements, and a return means for returning from the rolling element tank to the supply unit of the separator through a circulation pipe. While preventing the entanglement between each other and the effect of loosening the prepared sludge, the separation efficiency is improved.

The hard-to-dehydrate organic material is a fibrous material, and when the fiber content having a predetermined property to be collected is made to have a fiber length of 0.1 mm to 5 mm and a fiber diameter of 1 μm to 50 μm, a strong coagulated floc can be obtained by mixing with the hardly dewatered sludge. It can be formed, and a dehydrated cake with a low water content can be produced by a dehydrator at a later stage.

The extraction apparatus of the present invention can continuously process the sludge preparation / separation / recovery process, and becomes very compact when the devices are integrated. The dewatering organic matter in the sludge is effectively used for the sludge treatment in the treatment system as a dehydrating aid, and the easily degradable organic matter is returned to the biological treatment tank. The reaction period in the biological treatment process can be shortened. It can contribute to the improvement of the processing efficiency of the entire treatment plant. There is no need to purchase separate dehydration aids, and there is no need to store and supply dehydration aids. In addition, the hardly dehydrated organic substance extracted as a dehydrating aid does not contain an easily decomposable organic substance and can be stored for a long period of time.

It is a flowchart of the sludge processing method which concerns on this invention. Similarly, it is the graph which compares the fiber collect | recovered with the toilet paper and the extraction apparatus. Similarly, it is the reference micrograph which shows the fiber obtained with the extraction apparatus. Similarly, it is a chart diagram of the extraction device. It is a flowchart of the sludge processing method which concerns on the Example of this invention. Similarly, it is a detailed view of the extraction device. Similarly, it is explanatory drawing of the extraction apparatus of another Example. Similarly, it is a detailed view of the extraction device of another embodiment 1. Similarly, it is detail drawing of the extraction apparatus of other Example 2. FIG. Similarly, it is detail drawing of the extraction apparatus of other Example 3. FIG. Similarly, it is a flowchart at the time of employ | adopting OD method by the sludge treatment method of the other Example 1. FIG. Similarly, it is a flowchart at the time of employ | adopting MBR with the sludge processing method of the other Example 2. FIG. Similarly, it is a flowchart at the time of employ | adopting for the process of mixed raw sludge by the sludge processing method of the other Example 3. FIG.

The extraction device 2 of the present invention is premised on use in a sewage treatment plant or the like, extracts a predetermined fibrous material from sludge (including sewage) at the front stage of the treatment plant, and hardly dehydrates generated after the treatment plant. When dewatering sludge, it aims at adding the fibrous material as a dehydrating aid and improving the dehydrating property of the hardly dewatered sludge.
The hardly dewatered sludge is sludge whose fiber content that is the core of aggregation has been greatly reduced by biological treatment or the like, resulting in poor dewaterability. For example, digested sludge produced in a digestion tank, OD sludge produced in a reaction tank of the OD method, etc. are hardly dehydrated sludge.

FIG. 1 is a flowchart of the sludge treatment method according to the present invention. The biological treatment tank 1 for biologically treating sludge, the extraction device 2 for selectively collecting the fiber content in the sewage flowing from the sewer, the sludge treated in the biological treatment tank 1 and the fiber content recovered by the extraction device 2 It comprises a mixing tank 3 for mixing, an agglomeration mixing tank 4 for adding a flocculant to the sludge mixed with fibers in the mixing tank 3, and a dehydrator 5 for solid-liquid separation of the agglomerated sludge generated in the agglomeration mixing tank 4.
In addition, as shown with a broken line, the fiber part isolate | separated with the extraction apparatus 2 may be sent to the coagulation mixing tank 4, and you may add simultaneously with a polymer flocculant. As the dehydrator 5, a known dehydrator such as a screw press, a belt press, or a centrifugal dehydrator can be used.

In the present invention, since the fiber content in the sewage is used as a dehydration aid, the fiber content in the sewage that has flowed into the sewage treatment plant is recovered by the extraction device 2. The recovered fiber is added to the hardly dehydrated sludge before aggregation and functions as a nucleus of aggregation. If a dehydrating aid having an appropriate property is added to the sludge, a strong coagulated floc is formed and the dehydrating property is improved. Therefore, the nature of the dehydrating aid is selected in advance to be suitable for the treated sludge.
In the present invention, only the fiber having a predetermined property is collected and used as a dehydrating aid, thereby improving the dehydrating property.

Here, as a result of repeating trial and error and experiments by the present inventors, the use of toilet paper composed of plant fibers as a dehydrating aid has resulted in a significant reduction in the moisture content of the dehydrated cake. It was. Therefore, focusing on the properties of the toilet paper fibers, we succeeded in reducing the moisture content by using the same fiber content as the toilet paper as a dehydrating aid.

FIG. 2 is a graph comparing the toilet paper and the fibers collected by the extraction device 2. In the graph, the horizontal axis represents the length of the fiber, and the vertical axis represents the number of fibers. The sludge sent from the toilet paper and the sludge sent to the extraction device 2 of the present invention was sieved with 100 mesh. A comparison is made between the fiber obtained by separation and the fiber obtained by separating the sludge sent to the extraction device 2 with a rotating cylindrical screen having a pore diameter of Φ650 μm. The toilet paper was examined with a microscope after immersion stirring.

From the comparison results, it was found that the fiber distribution (fiber length, number of individuals) in the sewage sludge is very similar to that of toilet paper. Moreover, it turns out that it is preferable from the point of workability | operativity at the time of the addition to sludge, mixing, and dehydration to set the fiber length as 0.1 mm-5 mm as a property of the fiber collect | recovered.

FIG. 3 is a reference micrograph of the fiber collected by the extraction device 2, and it was found that the fiber diameter was not different and was in the range of 1 μm to 50 μm, similar to toilet paper.

From these, the property distribution of the fiber recovered by the extraction device 2 is very similar to the fiber property of the toilet paper, and the fiber content recovered by the extraction device 2 of the present invention is equivalent to the fiber content of the toilet paper. It can be seen that it is preferable as a dehydrating aid.

Note that toilet paper does not dissolve even when immersed in water, and only the fibers constituting the sheet are unwound and dispersed. Therefore, it is considered that a large amount of fibers derived from toilet paper are present in the sewage sludge.

FIG. 4 is a chart of the extraction device. The extraction device 2 used in the present invention comprises a preparation step 6 for continuously crushing and subdividing the granular solids while loosening the fibers and the granular solids, and the fiber content. The separation process 7 which isolate | separates solids other than these, and the collection | recovery process 8 which collect | recovers the fiber components used as a dehydration adjuvant are provided.

<Preparation process>
The solid matter in the sewage that has flowed into the sewage treatment plant is mainly composed of easily degradable organic matter derived from food residues, in addition to the vegetable fiber component of the hardly decomposable organic matter that is the main component of toilet paper collected as a dehydrating aid. Contaminants and SS as components are mixed, and they may be intertwined with the fiber. Therefore, in the preparation step 6, it is necessary to prepare sludge by untangling the fiber, adjusting the length of the fiber beyond the recovery range, and finely crushing the foreign matter or SS. You may subdivide in the state which poured the dilution water at the time of the preparation process 6, and made the sludge density | concentration low.

In the preparation step 6, the impurities and SS containing the fiber to be collected may be subdivided by the grinding machine 9. Since most of the fiber components are entangled with each other or with impurities, it is difficult to remove small impurities below the lower limit of the recovery range with the separator 10 as they are. Therefore, the fiber component is subdivided by the grinding machine 9 so that the fiber component and the impurities can be easily separated. When the main impurities are food residues, the fiber content inside the food residues can be extracted by grinding and other organic matters can be subdivided.

The crusher 9 may be any disk type, roller type, pulverized wood, etc., as long as it can continuously crush and subdivide the fiber, but it is a hardly decomposable organic substance (fiber). When both the easily decomposable organic powders are pulverized into powder, it is difficult to separate the fiber effective as a dehydrating aid. Therefore, an apparatus that can grind only the solids that are easily decomposable organic substances is desirable.

<Separation process>
In the separation step 7, the fiber portion prepared in the previous step is sieved using the separator 10 to separate the predetermined fiber portion and small impurities below the lower limit of the recovery range.
The fiber is prepared in the previous step, and the foreign matter entangled with the fiber is unwound. Therefore, if it is sieved so that the fibers within the collection range remain, only the fibers with a predetermined property can be collected. When the subdivided fibers are sifted, the foreign matter entangled with the fibers before the subdivision is removed, and at the same time small fibers below the recovery range are also removed.

Separation aid that separates contaminants by spraying washing water when water is separated, separation aid that unwinds fibers and contaminants by dipping, or fibers and contaminants during separation by multiple rolling elements Separation aids that prevent entanglement may be used.

By spraying the washing water, it is possible to further remove a small amount of foreign matter adhering to the fiber content or a small fiber content below the recovery range. Moreover, by immersing the sludge that has been subdivided at the time of separation, it is possible to separate and reliably separate a small amount of foreign matter adhered to the inside of the fibers or a small fiber portion below the recovery range. Furthermore, by mixing a plurality of rolling elements into the subdivided sludge, the fibers are prevented from being entangled in the separation step, and the effect of loosening the prepared sludge is exhibited, so that the separation efficiency is improved.

In addition, the waste water containing the impurities discharged | emitted from the separator 10 can be solid-liquid separated by clarification filtration etc., and clarified water can be reused as washing water.

The separator 10 may be any type such as a cylindrical type, a belt type, a vibration sieve type, etc., as long as it separates the fiber component having a predetermined property and the finely divided impurities.

<Recovery process>
In the recovery step 8, the fiber having a predetermined property separated in the separation step 7 is continuously recovered.
The recovery device 11 is appropriately selected to be suitable for the type of the separator 10. For example, when the separator 10 is cylindrical, the recovery device 11 employs a screw conveyor system inserted in the separator. Moreover, when the separator 10 is a belt type, the collection | recovery apparatus 11 employ | adopts the scraper pressed on the filtration surface. Any device that can continuously discharge from the separator 10 may be used.

The collected fiber within a predetermined range is sent to the mixing tank 3 as a dehydrating aid and mixed with the hardly dewatered sludge as the core of aggregation.
Note that most of the solids such as foreign matters separated by the separator 7 are composed of easily decomposable organic substances, and if sent to the biological treatment tank 1, sludge volume reduction can be achieved without requiring a long biological treatment. Can contribute.

<Pretreatment process>
Further, in the case where large contaminants exceeding the upper limit of the recovery range are mixed in the sludge flowing into the sewage treatment plant, the following pretreatment step 12 may be added before the preparation step 6.
In the pretreatment process 12, large contaminants in the sewage flowing into the sewage treatment plant are removed by the pretreatment device 13. Large contaminants are inappropriate as dehydration aids and hinder preparation in the preparation step 6 of the next step. In this step, large contaminants exceeding the upper limit of the recovery range, SS containing the fiber to be recovered, and small The purpose is to separate contaminants and remove large contaminants. Accordingly, the pretreatment device 13 may be any device as long as it can remove impurities exceeding the upper limit of the collection range, and may be a bar screen, a sieve, or a drum screen.

The preparation process 6, the separation process 7, and the recovery process 8 described above can be unitized and performed in one apparatus, and the pretreatment process 12 may be included in the apparatus.

FIG. 5 is a flow chart of a sludge treatment method when digested sludge is treated at a sewage treatment plant. The sewage that has flowed into the sewage treatment plant first flows into the settling basin 14. In the first settling basin 14, sewage flows gently, and organic matter containing fiber is precipitated. As the main component of the precipitate, the fiber content is mainly toilet paper, and the solid content is food residue. The fiber length of toilet paper is 0.1 to 30 mm, and the fiber diameter is 1 to 50 μm. The sediment is extracted and collected from below as raw sludge.

The raw sludge withdrawn from the sedimentation tank 14 is biologically treated in the digestion tank 15 to reduce the volume. A part of the raw sludge withdrawn from the settling basin 14 is conveyed to the extraction device 2 and selectively collects fibers having a predetermined property. Contaminants other than the fibers separated by the extraction device 2 are returned to the digestion tank 15 and contribute to the digestion efficiency in the digestion tank.

Digested sludge, which is a difficult-to-dehydrate sludge whose volume has been reduced by digestion tank 15, is added with fiber components (dehydration aid) and a flocculant having predetermined properties in mixing tank 3 and agglomeration mixing tank 4, respectively. After the formation, solid-liquid separation is performed by the dehydrator 5 to obtain a dehydrated cake having a low water content.

FIG. 6 is a detailed view of the extraction device in the embodiment. The extraction device 2a mainly includes a preparation step 6, a separation step 7, and a recovery step 8. In the present embodiment, a grinding machine 9a for subdividing raw sludge is constituted by opposing disks 16 and 17, and is provided at the end of a separator 10a constituted by a rotating cylindrical screen 18. The prepared sludge discharged from the pulverizer 9 a is conveyed to the other end by a screw blade 19 erected on the inner surface of the screen 8, and finely divided impurities and the like are separated and discharged from the opening of the screen 18. The fiber component having a predetermined property is conveyed to the other end of the screen 18 by the screw blade 19 and collected.

Since the raw sludge sent from the first sedimentation basin 14 is entangled with fibers and impurities, the fibers entangled in the preparation step 6 are fibers having a fiber length of 0.1 mm to 0.5 mm and a fiber diameter of 1 μm to 50 μm. Prepare in minutes. The raw sludge is diluted with diluting water, and refinement is performed by a pulverizer 9a in which the rotating disk 16 and the fixed disk 17 are opposed to each other. The raw sludge supplied to the inside of the opposed disks 16 and 17 is discharged outside while being refined by rough minute irregularities on the disk surface, and the subdivided raw sludge is sent to the separation step 7.

A specific configuration will be described in detail. In the grinding machine 9a, disk-shaped disks 16 and 17 each having a conical recess 20 formed therein are rotatably opposed from the outer periphery toward the center. One of the disks is a fixed disk 17, and the outer peripheral portion is fixed to another member. In this embodiment, radial ribs 21 are fixed to the separator. The other disk is a rotating disk 16 from which raw sludge is supplied from a supply pipe 23 connected to a supply port 22 provided at the center. The power from the drive unit 24 is transmitted to the supply pipe 23 via a power transmission means 25 such as a belt, and the supply pipe 23 and the rotary disk 16 are rotated. If necessary, the supply pipe 23 and the rotating disk 16 are supported by bearings or the like at appropriate positions.

The volume of the center part of the opposing disks 16 and 17 is large, and the volume is narrowed toward the outer periphery. The gap at the outer peripheral edge is set to 1 mm or less, and the raw sludge supplied to the center is subdivided on the inner surface of the disk while being transferred to the outer peripheral side by the press-fitting pressure by the supply means (not shown) and the centrifugal action of the rotating disk 16. Is done. By subdividing, fibers having a length of 0.1 mm to 30 mm are prepared to have a length of 0.1 mm to 5 mm.

In the present embodiment, dilution water is supplied to the raw sludge to increase the effect in the preparation step 6. Specifically, the entangled fibers and contaminants in the raw sludge can be unwound by the crushing action in diluted water and easily separated. Large contaminants are crushed to a size that is easy to remove by fragmentation.

Since the grinding machine 9a is integrated in the separator 10, the prepared sludge discharged to the outside of the opposed disks 16 and 17 can be continuously separated by the separator 10a constituted by the rotating cylindrical screen 18. It becomes.

When the amount of processing is large, it can be appropriately handled by a known technique such as increasing the diameter of the opposing disks 16 and 17 or arranging the opposing disks 16 and 17 in multiple stages. Further, as shown in FIG. 7, when the grinding machine 9a is installed outside the separator 10a, the opposed disks 16 and 17 are surrounded by the casing 26, and the prepared sludge can be sent to the separator 10a via the transfer pipe 27. In this case, the preparation / separation process can be continuously performed.

The separator 10a of the present embodiment is composed of a rotating cylindrical screen 18. The prepared sludge supplied to the supply unit 28a at the end of the screen 18 is conveyed to the other end by the screw blade 19 erected on the inner surface of the screen 18 in the center direction, and finely divided impurities and the like are filtered. Are separated and discharged from a large number of pores provided in the screen 18. A separation tank 29 is disposed below the filtration surface 52 a of the rotating cylindrical screen 18 and accumulates easily decomposable organic substances such as foreign substances that have passed through the opening of the screen 18.

A shaft 30 extends from both ends of the screen 18 and is rotatably supported. When the grinding machine 9a is installed inside the screen 18, the screen 18 is rotatably supported through the supply pipe 23 of the grinding machine 9a. The power from the drive unit 31 is transmitted to the screen 18 through power transmission means 32 such as a belt, and the screen 18 is rotated.

In the present embodiment, the wall plate of the separation tank 29 is raised to the extent that it overlaps the screen 18, and a part of the screen 18 is immersed by storing immersion water therein. Further, the vicinity of the extraction portion 33a of the screen 18 is gradually reduced in a conical shape. By carrying out like this, it is possible to enhance the action of dispersing only a small amount of foreign substances adhering to the inside of the fiber or a small fiber content below the recovery range while loosening it in the immersion water and gravity separating it into the separation tank together with the water. An equivalent effect can be expected even if an injection device 34 for injecting high-pressure water to the prepared sludge being separated is provided.

A return pipe 35 is connected to the separation tank 29, and impurities mainly composed of easily decomposable organic substances separated and discharged to the separation tank 29 are returned to the biological treatment tank 1. The fiber part which mainly consists of the vegetable fiber which is a hardly decomposable organic substance is extracted in the front | former stage of the biological treatment tank 1, and the ratio of the easily decomposable organic substance derived from a food residue becomes high in the biological treatment tank 1. FIG. Therefore, the reaction time required for biological treatment is short, and the treatment efficiency of the entire sewage treatment plant is improved.

A fiber having a predetermined property that remains in the screen 18 without being separated from the opening of the screen 18 is conveyed to the other end of the screen 18 by a screw blade 19.

The recovery device 11a of the present embodiment uses a screw blade 19 that conveys the fiber content inside the screen 18 as the recovery device so as to fit the rotating cylindrical screen 18. Screw blades 19 are spirally wound around the inner surface of the screen 18, and the residual fibers are conveyed to the extraction unit 33 as the screen 18 rotates and stored in the collection tank 36.
In the case of the cylindrical screen 18, a screw shaft in which a screw blade is wound around the shaft may be inserted and used as a recovery device.

Since the recovered fiber has no readily decomposable organic matter derived from food residues that rot in a short time, it does not require special treatment and equipment and can be stored for a long time.

FIG. 8 is a detailed view of the extraction device of another embodiment 1, in which the extraction device 2b is disposed with the extraction portion 33b inclined upward. The prepared sludge discharged from the pulverizer 9b of the extraction device 2b is loosened and dispersed with immersion water, and small impurities are separated and discharged by the screen 18 of the separator 10b. Then, it is conveyed to the extraction unit 33b and accumulated in the collection tank 36.

Since the separator 10b is inclined, the vicinity of the extraction unit 33b of the screen 18 is not immersed, and the same effect as the extraction device 2 of FIG. 5 is obtained due to the washing / dispersing effect by the immersion and the gravity separation action near the extraction unit 33b. The effect is obtained.
Other component configurations are the same as those of the embodiment shown in FIG.

FIG. 9 is a detailed view of the extraction device of another embodiment 2, in which a plurality of rolling elements 37 are mixed inside a rotating cylindrical screen 18. The extraction device 2c mixes with the prepared sludge discharged from the crusher 9c inside the screen 18 to prevent the fibers from being entangled in the separation step 7 and also has an effect of loosening the prepared sludge, so that the separation efficiency is improved.

The material of the rolling element 37 is not limited as long as it is a heavy object such as metal, synthetic rubber, and resin. However, the rolling element 37 is rolled while being conveyed inside the screen 18, and therefore has low impact resistance and vibration absorption from the viewpoint of vibration and noise. Is desirable.

The separator 10c is provided with an extraction portion 33c for collecting a fiber having a predetermined property on the cylindrical surface of the screen 18, and the opening of the extraction portion 33c is made larger than the fiber and smaller than the diameter of the rolling element 37. Only minutes can be extracted. The rolling element 37 is further conveyed from the extraction unit 33 c and discharged from the end of the screen 18 to the rolling element tank 38. The rolling elements 37 stored in the rolling element tank 38 are supplied to the end of the screen 18 on the side of the grinding machine 9c via the circulation pipe 42 by a known return means 39. The rolling element 37 may be washed as necessary.
Other component configurations are the same as those of the embodiment shown in FIG.

FIG. 10 is a detailed view of the extraction device of another embodiment 3, wherein the sludge is subdivided by a grinding machine 9d composed of a roller 41 that rotates while sliding on the inner wall of the cylindrical screen 40, and the prepared sludge is separated into a belt type. This is an extraction device 2d that separates contaminants while being supplied to the machine 10d and conveyed to the extraction unit 33d, and a predetermined fiber component is extracted by the scraper 43 in the extraction unit 33d.

The crusher 9d inserts the cylindrical screen 40 into a cylindrical casing 44, one of which is closed, with a predetermined interval in the radial direction, and rotates while sliding while pressing the sliding member 41 against the inner wall of the cylindrical screen 40. I am letting. In this embodiment, a roller 41 is used as a sliding contact member, and a plurality of rollers 41 are rotated. A supply pipe 23 is connected to the center of the opening of the cylindrical screen 40 to supply sludge. The power from the driving machine 46 is transmitted to the roller 41 via power transmission means 47 such as a belt, and the roller 41 is rotated.

The sludge supplied from the supply pipe 23 into the cylindrical screen 40 is subdivided while being ground by the pressing action and centrifugal action of the roller 41, and passes through the pores of the cylindrical screen 40. The prepared sludge transferred between the cylindrical screen 40 and the casing 44 is supplied to the separator 10 d through a transfer pipe 48 provided in the casing 44.
In this embodiment, the roller 41 is slid on the inner wall of the cylindrical screen 40, but the sliding contact member is not limited as long as the same effect is obtained.

The separator 10d has a configuration in which an endless belt 51 having a large number of pores is wound around a plurality of rolls 50, and the prepared sludge is supplied to the upper filtration surface 52. The endless belt 51 is made to travel while driving the roll 50 to separate small impurities. A separation tank 29 is disposed below the filtration surface 52d, and small filtered impurities are stored. A return pipe 35 is connected to the separation tank 29, and contaminants mainly composed of easily decomposable organic substances separated and discharged to the separation tank 29 are returned to the biological treatment tank 1. If necessary, a cleaning device 53 for regenerating the filtration surface 52d is disposed at an appropriate position. As the washing water, a filtrate obtained by separating impurities from the separation tank 29 by clarification filtration or the like may be used. The prepared sludge supply unit 28d may be provided with a cover 54 for preventing overflow, and the prepared sludge may be immersed therein.

As the recovery device 11 d, the scraper 43 is pressed against the extraction unit 33 d of the endless belt 51, and predetermined fiber remaining on the upper surface of the endless belt 51 is scraped off by the scraper 43. The scraped fibers are stored in the collection tank 36.

The crusher, the separator, and the recovery device of the extraction device 2 can be used in various combinations, and can be appropriately selected according to the specifications and the processing site.

FIG. 11 is a flowchart when the OD method is adopted in the sewage treatment plant. The sewage flowing from the sewer is sent to the reaction tank 55 that performs the OD method through the flow path, and a part thereof is sent to the extraction device 2. The sludge sent to the extraction device 2 collects the fiber content, and the discharged contaminants and moisture are sent to the reaction tank 55. Since the fiber content of the hardly decomposable organic matter is recovered from the sewage, the contaminants sent to the reaction tank 55 contain a large amount of easily decomposable organic matter. Therefore, when an easily decomposable organic substance is sent to the reaction tank 55, the reaction period for performing biological treatment is shortened.
In the reaction tank 55, activated sludge treatment is performed, and the activated sludge is sent to the final sedimentation basin 56.
In the final sedimentation basin 56, sludge is precipitated, and the supernatant water is sent to a disinfection tank (not shown) and discharged after disinfection. The precipitated sludge is sent to the mixing tank 3 and mixed with the fiber collected by the extraction device 2.
The sludge to which the fiber is added is sent to the coagulation / mixing tank 4, and a coagulant is added to produce the coagulated sludge. The agglomerated sludge is sent to the dehydrator 5 and dehydrated.

FIG. 12 is a flow chart when MBR (membrane separation activated sludge method) is adopted in the sewage treatment plant. The sewage flowing from the sewer is separated by a fine inflow screen 57 disposed in the flow path, the solid matter is sent to the extraction device 2, and the other sewage is sent to the preparation tank 58. Since the recovered material separated by the inflow screen 57 is separated by the fine inflow screen 57, impurities and the like are mixed in addition to the fibers.
The solids sent to the extraction device 2 are collected with the fiber content within the collection range, and other impurities, moisture, etc. are sent to the preparation tank 58. The sewage sent to the preparation tank 58 is sent to the reaction tank 55 that performs the membrane separation activated sludge method. Since the extraction device 2 collects the fiber of the hardly decomposable organic matter from the sewage, the foreign matter to be sent to the preparation tank 58 contains a lot of easily decomposable organic matter. Therefore, when an easily decomposable organic substance is sent from the preparation tank 58 to the reaction tank 55, the reaction period for performing biological treatment is shortened.
The filtrate that has passed through the biofilm in the reaction tank 55 is sent to a disinfection tank (not shown) and discharged after disinfection.
The sludge extracted from the reaction tank 55 is sent to the mixing tank 3 and mixed with the fiber recovered by the extraction device 2. The sludge to which the fiber is added is sent to the coagulation / mixing tank 4, and a coagulant is added to produce the coagulated sludge. The agglomerated sludge is sent to the dehydrator 5 and dehydrated.

FIG. 13 is a flowchart when processing mixed raw sludge in a sewage treatment plant. Here, since the amount of generated sewage generally decreases at night compared to the daytime, the amount of sewage that is initially withdrawn from the settling basin 14 decreases. Accordingly, the mixed raw sludge becomes difficult to dehydrate because the proportion of excess sludge sent from the final sedimentation basin 56 increases. Therefore, the dewatering efficiency is improved by employing the sludge treatment method of the present invention for dewatering the mixed raw sludge.
The sewage flowing from the sewer is first sent to the settling basin 14. In the first sedimentation basin 14, sewage flows gently, and the sediment is extracted as raw sludge and sent to the extraction device 2 and the mixing tank 3. In addition, the supernatant water of the first sedimentation tank 14 is sent to the reaction tank 55. The extractor 2 collects the fiber and the recovered fiber is sent to the mixing tank 3. Further, the foreign matter discharged from the extraction device 2 is sent to the reaction tank 55. Since the extraction device 2 collects the fiber of the hardly decomposable organic matter from the raw sludge, the impurities and the like discharged from the extraction device 2 contain a lot of easily decomposable organic matter. Therefore, when an easily decomposable organic substance is sent to the reaction tank 55, the reaction period for performing biological treatment is shortened.
The sludge decomposed in the reaction tank 55 is sent to the final sedimentation tank 56. In the final sedimentation basin 56, sludge is precipitated, and the supernatant water is sent to a disinfection tank (not shown) and discharged after disinfection. The precipitated sludge is sent to the mixing tank 3 and mixed with the raw sludge drawn out from the settling tank 14 first to become mixed raw sludge. Moreover, the fiber part collect | recovered with the extraction apparatus 2 is also sent to the mixing tank 3, and is added to mixing raw sludge.
The mixed raw sludge to which the fibers are added is sent to the flocculation mixing tank 4, and a flocculating agent is added to generate the flocculated sludge. The agglomerated sludge is sent to the dehydrator 5 and dehydrated.

The fiber extraction apparatus according to the present invention effectively utilizes the fiber content in the sludge that has flowed into the sewage treatment plant as a dehydration aid, and can procure the dehydration aid from unnecessary materials in the treatment plant. Since it is not necessary to purchase and store dehydration aids, not only the running cost is reduced, but also the equipment can be downsized.
The dewatering organic matter in the sludge is effectively used for the sludge treatment in the treatment system as a dehydrating aid, and the easily degradable organic matter is returned to the biological treatment tank. The reaction period in the biological treatment process can be shortened. It can contribute to the improvement of the processing efficiency of the entire treatment plant.

DESCRIPTION OF SYMBOLS 9 Crusher 10 Separator 11 Recovery device 16 Rotating disk 17 Fixed disk 18 Screen 19 Screw blade 22 Supply port 23 Supply pipe 29 Separation tank 33 Extraction part 28 Supply part 34 Injection apparatus 35 Return pipe 37 Rolling body 38 Rolling body tank 39 Return Means 40 Cylindrical screen 41 Sliding member, roller 42 Circulating pipe 43 Scraper 44 Casing 48 Transfer pipe 50 Roll 51 Endless belt 52 Filtration surface

Claims (11)

In a device that extracts specific materials from sludge generated in the sewage treatment process,
A grinding machine (9) for subdividing sludge;
A separator (10) for separating a hardly decomposable organic substance and an easily decomposable organic substance from the ground prepared sludge;
Equipped with a recovery device (11) for extracting persistent organic matter,
An extraction apparatus characterized by continuously separating and recovering a predetermined hardly decomposable organic substance. A separation tank (29) for collecting easily decomposable organic substances is provided below the separator (10),
The extraction apparatus according to claim 1, wherein a return pipe (35) for returning easily decomposable organic matter to a biological treatment tank of a sewage treatment plant is connected to the separation tank (29). The crusher (9),
The rotating disk (16) and the fixed disk (17) are configured to face each other,
The supply pipe (23) is connected to the supply port (22) opened at the center of the rotating disk (16),
3. The extraction device according to claim 1, wherein a predetermined gap is provided at the outer peripheral end of the opposing disk (16, 17). The crusher (9),
A cylindrical screen (40) is inserted into a cylindrical casing (44) closed on one side,
The sliding contact member (41) that is in sliding contact with the inner wall of the cylindrical screen (40) is configured to be rotatably provided,
A supply pipe (23) in the center of the opening of the cylindrical screen (40);
3. Extraction device according to claim 1 or 2, characterized in that a transfer pipe (48) is provided in the casing (44). Said separator (10),
It is composed of a cylindrical screen (18) arranged rotatably,
The recovery device (11)
The extraction device according to any one of claims 1 to 4, wherein the extraction device comprises a screw blade (19) wound in a spiral shape provided in a screen (18). The extraction device according to claim 5, wherein the vicinity of the extraction section (33) of the separator (10) is gradually reduced in a conical shape. Said separator (10),
A plurality of rolls (50...) Are wound around freely to form an endless belt (51) having a large number of pores.
The recovery device (11)
The extraction device according to any one of claims 1 to 4, comprising a scraper (43) disposed behind the filtration surface. The filtration surface (52) including the supply part (28) of the separator (10) is stored in immersion tank (29) and immersed in the immersion tank (29). The extraction device according to item. The extraction device according to any one of claims 1 to 8, further comprising an injection device (34) for injecting the filtration surface (52) of the separator (10) with high-pressure water. A plurality of rolling elements (37 ...) are mixed in the separator (10),
A rolling element tank (38) for collecting the rolling elements (37 ...);
The return means (39) for returning to the supply part (28) of the separator (10) from the rolling element tank (38) through the circulation pipe (42) is provided. The extraction device according to claim 1. The hardly dehydrating organic material is a fibrous material,
The fiber of the predetermined property to collect
The extraction apparatus according to any one of claims 1 to 10, wherein the fiber length is 0.1 mm to 5 mm, and the fiber diameter is 1 µm to 50 µm.

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