JP2007021413A - Apparatus and method for treating sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for treating sludge capable of preventing the sludge inflow port of a centrifugal dewatering machine from being clogged with screenings in screenings containing sludge. <P>SOLUTION: The apparatus for treating the sludge 1' comprises a first crusher 6 for crushing a solid substance in the screenings containing sludge into a smaller particle, the centrifugal dewatering machine 8 for receiving the screenings containing sludge crushed by the first crusher 6 to concentrate it, a second crusher 9 for receiving the screenings containing sludge dewatered by this centrifugal dewatering machine 8 to crush it, a pretreatment tank 11 for receiving the screenings containing sludge crushed by the second crusher 9 to easily digest it, and a digestion tank 12 for fermenting a pre-treated liquid pre-treated in this pretreatment tank 11 to generate methane. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sludge treatment facility and a sludge treatment method. More specifically, the present invention relates to a dehydrator for concentrating sludge containing sludge discharged from a first settling tank such as a sewage treatment plant and processing sludge containing sludge. Sludge treatment equipment and sludge treatment that can improve the operating rate by preventing clogging of the sludge inlet into which sludge containing sludge flows, and also enable stable operation of pretreatment and digestion in the subsequent stage. Regarding the method.

  Sewage such as sewage and wastewater is treated with activated sludge in an aeration tank, and the supernatant of treated water that has been treated with activated sludge is discharged to rivers, while the sludge containing sludge is concentrated, adjusted, heated and hydrolyzed. There is a sludge treatment facility that is fermented in a digestion tank to obtain methane gas and then dehydrated into a dehydrated cake. As such a sludge treatment facility, for example, one having a configuration described later is known. Hereinafter, the sludge treatment facility according to Conventional Example 1 will be described with reference to the accompanying drawings.

  The sludge treatment facility according to Conventional Example 1 is as shown in FIG. That is, sewage is first introduced into a first sedimentation basin (corresponding to a first sedimentation tank), solid substances such as residue are settled and separated in this first sedimentation tank, and then passed through an aeration tank (final sedimentation basin (final). It is sent to a settling tank) and left in the final settling basin, and after adjusting the supernatant pH and the like, it is discharged as discharge water. On the other hand, the sludge deposited on the bottom of the first sedimentation basin and the final sedimentation basin is collected and sent to the sludge concentration tank, where it is further condensed in the sludge concentration tank. Next, after digestion by anaerobic fermentation in the sludge digestion tank, it is sent to a sludge storage tank to which an ultrasonic oscillator is attached. In this sludge storage tank, first, after irradiating the sludge with ultrasonic waves for a time, a flocculant is added to perform a coagulation sedimentation treatment. The coagulated sedimented sludge is sent to a sludge dewatering machine and dehydrated to become dehydrated sludge. Next, the dewatered sludge is sent to a cake hopper and is transported out of the cake hopper (see, for example, Patent Document 1).

  The sludge treatment facility according to Conventional Example 2 is as shown in FIG. 3 of the schematic diagram and FIG. 4 of the schematic diagram of the purification device. That is, the first settling basin 51 to which the sewage is supplied, the aeration tank 52 for treating the sewage flowing out from the first settling basin 51 with the activated sludge, and the activated sludge from the aerated treatment liquid treated with the activated sludge in the aerated tank 52. A final sedimentation basin 53 for separating the sludge, a pretreatment device 55 for facilitating digestion of the sludge separated and removed from the final sedimentation basin 53, and a decomposition tank (digestion tank) for anaerobically digesting the pretreated sludge ) 56, a sludge treatment facility comprising a dehydrator 57 for dehydrating the processed material in the decomposition tank 56 and a return line 61 for returning the dehydrated liquid from the dewaterer 57 to the initial sedimentation tank 51. A purification device 59 configured as described later is disposed between the aeration tank 52 and the return line 61. As the dewatering device 57 in such a sludge treatment facility, a press-type dewatering device, a centrifugal separator (hereinafter referred to as a centrifugal dewatering device), or the like can be used. In addition, the code | symbol 54 shown in FIG. 3 is a concentration apparatus for concentrating sludge to high concentration (for example, sludge density | concentration 8-15%), As such a concentration apparatus, a press-type dehydrator, a centrifugal dehydrator, etc. Is used.

  The purification device 59 is configured as shown in FIG. That is, it comprises a septic tank 80 having an aeration section 81 for treating the dehydrated liquid with activated sludge and a liquid filtration section 82 for separating and removing the activated sludge from the aerated liquid. The aeration unit 81 is provided with an aeration gas supply port 83 in the vicinity of the tank bottom, and the liquid filtration unit 82 is provided with a unit 84 for membrane separation at an intermediate height of the tank. And the liquid filtered with this liquid filtration part 82 is first returned to the settling basin 51 via the return line 61 (for example, refer patent document 2).

  As a typical centrifugal dehydrator according to the conventional example, for example, one having a configuration as shown in FIG. This centrifugal dehydrator is provided with a rotating ball 91 that is formed in a substantially cylindrical shape in which an inner peripheral portion on one end side is inclined in a tapered shape and is rotatably supported around a central axis O. In the rotating ball 91, a screw conveyor 97 is disposed coaxially with the rotating ball 91, and is configured to rotate in the same direction as the rotating ball 91 with a differential speed. The workpiece (sludge containing sludge) P supplied from the central portion in the axis O direction into the annular space C between the screw conveyor 97 and the rotating ball 91 is separated into solid and liquid by the centrifugal force of the rotating ball 91. The separated solid content S is discharged from a solid content discharge port 94 opened to one end of the annular space C. Further, a valve body 104 for adjusting the discharge amount of the solid content S is provided at the solid content discharge port 94, and the separation liquid L is opened to the inner peripheral side of the annular space C on the other end side in the axis O direction. It is configured to be discharged from the path 101.

Reference numerals 92 and 93 in the vicinity of both ends in the longitudinal direction (left and right direction in the figure) of the centrifugal dehydrator are substantially cylindrical shaft end portions, and reference numeral 95 formed by being externally fitted to the shaft end portions 92 and 93 is Reference numeral 96 denotes a rotating means such as a motor for rotating the rotating ball 91 via a belt 96a and a pulley 93a. Further, a bearing 98 that is fitted inside the shaft end portions 92 and 93 and supports the end portion of the screw conveyor 97 is provided at the right end portion of the screw conveyor 97 in the drawing. A thing is rotating means, such as a motor which rotates this screw conveyor 97 (for example, refer to patent documents 3).
Japanese Patent Laid-Open No. 11-19697 JP 2004-16969 A JP 2002-336735 A

  The dehydrator includes a belt press type dehydrator, a centrifugal dehydrator, a screw press, and a rotary pressure dehydrator. Any type of dehydrator can be used for the sludge treatment equipment as described above. . By the way, the sludge to be dehydrated and the drainage may contain relatively long residues such as hair and vinyl pieces. There is no problem when such residue-containing sludge and sewage are supplied to a belt press type dehydrator. However, when such slag-containing sludge or sewage is supplied to the centrifugal dehydrator, it is disposed at the center of the diameter inside the main body of this centrifugal dehydrator, provided at the outer periphery near the tip, A plurality of sludge inlets (diameter of about 40 mm) for discharging the sewage and flowing into the dewatering chamber are blocked with scum, resulting in a problem that sewage-containing sludge and sewage cannot be dewatered by a centrifugal dehydrator. Screw presses and rotary pressure dehydrators have similar problems.

  Incidentally, in such a centrifugal dehydrator, the sludge inlet is clogged after about 24 hours of operation, and can only be operated continuously for about 24 hours. Therefore, in order to remove clogs and residue from the sludge inlet, the operation of the dehydrator must be stopped and disassembly and assembly operations must be performed. There was a problem that maintenance cost increased. In addition, as described above, the concentration treatment of the sludge containing sludge is not continuously performed, so that the subsequent pretreatment and digestion treatment become unstable, and the treatment capacity of the sludge containing sludge may be reduced. there were.

  Therefore, the object of the present invention is to prevent clogging of the sludge inlet of the dehydrator caused by the residue in the residue-containing sludge when the residue-containing sludge discharged from the sedimentation tank is first processed. It is to provide a sludge treatment facility and a sludge treatment method.

  The present invention has been made in view of the above circumstances, and therefore, in order to solve the problem, the means employed by the sludge treatment facility according to claim 1 of the present invention is the solid substance in the sludge containing sludge. A first crusher that crushes into smaller particles, a dehydrator that accepts and concentrates sludge containing sludge crushed by this first crusher, and a second that accepts and crushes concentrated sludge dehydrated by this dehydrator A crusher, a pretreatment tank that accepts the concentrated sludge crushed by the second crusher for easy digestion, and a digester tank that ferments the pretreatment liquid pretreated in the pretreatment tank to generate methane. It is characterized by comprising.

  Means employed by the sludge treatment facility according to claim 2 of the present invention is the sludge treatment facility according to claim 1, wherein a receiving tank for receiving the residue containing sludge is provided on the upper stage side of the first crusher, A sludge return line communicating from the first crusher to the receiving tank is provided.

  The means adopted by the sludge treatment facility according to claim 3 of the present invention is the sludge treatment facility according to claim 2, wherein the second crusher crushes between the second crusher and the pretreatment tank. An adjustment tank that makes the concentration of the solid matter in the concentrated sludge uniform is provided, and a sludge return line that communicates from the adjustment tank to the second crusher is provided.

  The means adopted by the sludge treatment method according to claim 4 of the present invention is to treat the sludge containing sludge using the sludge treatment facility according to any one of claims 1 to 3. It is a feature.

  In the sludge treatment facility according to claims 1 to 3 of the present invention, a first crusher (for example, a macerator pump) for crushing the solid substance into smaller particles is disposed on the front side of the dehydrator. . Therefore, according to the sludge treatment facility according to claims 1 to 3 of the present invention, the sludge is crushed into small particles by crushing the residue such as hair and vinyl pieces in the residue containing sludge by the first crusher. Since it is supplied to the sludge inlet of the dehydrator, there is no fear that the drain inlet will be clogged with residue. Therefore, since the residue-containing sludge is stably and continuously concentrated, the concentrated sludge is stably pretreated and digested on the subsequent stage side.

    In the sludge treatment apparatus according to claim 2 of the present invention, a receiving tank for receiving the sludge containing sludge is provided on the front stage side of the first crusher, and a sludge return line communicating from the first crusher to the receiving tank is provided. ing. Therefore, according to the sludge treatment apparatus according to claim 2 of the invention, since the residue-containing sludge is circulated between the receiving tank and the first crusher and crushed, the residue can be supplied to the dehydrator. The particle size reduction efficiency of the residue by the first crusher is improved, and clogging of the sludge inlet of the dehydrator can be more reliably prevented.

  In the sludge treatment facility according to claim 3 of the present invention, an adjustment tank is provided between the second crusher and the pretreatment tank to make the concentration of solids in the concentrated sludge crushed by the second crusher uniform. In addition, a sludge return line communicating from the adjustment tank to the second crusher is provided. Therefore, according to the sludge treatment facility according to claim 3 of the present invention, the residue-containing concentrated sludge is solidified in the adjustment tank by circulating the residue-containing concentrated sludge between the second crusher and the adjustment tank. Since the uniformity of the partial concentration can be improved, the residue-containing concentrated sludge can be stably and efficiently pretreated and digested in the subsequent stage.

  In the sludge treatment method according to claim 4 of the present invention, the residue-containing sludge is treated using the sludge treatment facility according to any one of claims 1 to 3. Therefore, according to the sludge treatment method of claim 4 of the present invention, the residue-containing sludge is stably and efficiently pretreated and digested.

  Hereinafter, a sludge treatment facility according to an embodiment of the present invention for carrying out the sludge treatment method of the present invention will be described with reference to the accompanying drawings, taking as an example the case where the dehydrator is a centrifugal dehydrator. FIG. 1 is a schematic explanatory diagram of a sludge treatment facility according to an embodiment of the present invention. The configuration of the centrifugal dehydrator is substantially the same as that of the conventional centrifugal dehydrator described in paragraph [0006] (Japanese Patent Laid-Open No. 2002-336735). I'll leave you out.

  The code | symbol 1 shown in FIG. 1 is the sewage treatment equipment incorporating the sludge treatment equipment 1 'which concerns on the form of this invention. The sewage treatment facility 1 includes an initial sedimentation tank 2 into which sewage such as sewage to be treated flows, and an aeration tank 3 for treating the activated sludge from the primary treatment water flowing in from the first sedimentation tank 2. In addition, a final sedimentation tank 4 is provided for separating activated sludge from the aeration-treated aerated liquid flowing in from the aeration layer 3 and discharging the supernatant as treated water. And sludge treatment equipment 1 '. Sludge (moisture; about 94 to 99 wt%) containing hair, vinyl pieces, and the like sedimented on the bottom of the first sedimentation tank 2 and the final sedimentation tank 4, and microorganism sludge (moisture content) at the bottom of the final sedimentation tank 4 ; About 94-99 wt%) is provided. In order to make sludge containing about 94 to 99 wt% of water, a concentrating device may be provided between the first settling tank 2 and the receiving tank 5 and between the final settling tank 4 and the receiving tank 5. is there.

  Further, the residue-containing sludge containing residue such as hair and vinyl pieces discharged from the receiving tank 5 is crushed by a first crusher 6 having a crushing blade (not shown) and supplied to the pump 7. It has become. The first crusher 6 and the pump 7 are preferably replaced with a macerator pump having a crushing function and a pump function for simplification of equipment. As such a macerator pump, for example, a known configuration disclosed in Japanese Patent Laid-Open No. 6-154752 can be used.

  In addition, what is connected to the upper part of the receiving tank 5 from the said 1st crusher 6 is the 1st sludge return line 6a, Comprising: With this 1st sludge return line 6a, the receiving tank 5 and the 1st crusher 6 and The residue-containing sludge can be circulated and crushed. Therefore, it is possible to obtain an effect that the efficiency of reducing the size of the residue by the first crusher 6 is improved.

  The sludge containing sludge that has been reduced in size by the first crusher 6 is supplied via a pump 7 to a centrifugal dehydrator 8 having substantially the same configuration as the centrifugal dehydrator according to the conventional example. . Then, it is dewatered by the centrifugal dehydrator 8 to form a sludge containing concentrated sludge having a solid content of about 8 to 20 wt%, preferably 10 to 15 wt%, and having the same configuration as the first crusher 6. The residue-containing concentrated sludge that is supplied to the crusher 9 and crushed by the second crusher 9 is supplied to the adjustment tank 10. And the residue containing concentrated sludge supplied to this adjustment tank 10 is adjusted so that solid content concentration may become uniform. The second crusher 9 can also be a macerator pump.

  In addition, what is connected to the 2nd crusher 9 from the lower part of the said adjustment tank 10 is the 2nd sludge return line 9a, Comprising: The 2nd crusher 9 and the adjustment tank 10 with this 2nd sludge return line 9a By circulating the residue-containing concentrated sludge between them, the uniformity of the solid content concentration of the residue-containing concentrated sludge in the adjustment tank 10 can be improved.

The adjusted concentrated sludge whose solid content has been made uniform by the adjusting tank 10 is supplied to the pretreatment tank 11 and is solubilized in the pretreatment tank 11 in order to facilitate the subsequent digestion process.
Examples of the solubilization method of the adjusted concentrated sludge employed in the pretreatment tank 11 include various methods such as heating, ultrasonic waves, high voltage pulse application, high pressure gas introduction, ozone supply, pulverization, acid addition, alkali addition, or enzyme addition. Can be mentioned. However, from the viewpoint of effectively using methane generated by digestion, heating is preferable, and the adjusted concentrated sludge is 120 to 220 ° C. (preferably 150 to 180 ° C.) for 0.1 to 6 hours (preferably 0.1. It is heated and hydrolyzed under the condition of 2 to 2 hours. The reaction treatment liquid generated from the adjusted concentrated sludge under such conditions is supplied to the digestion tank 12.

  The reaction solution supplied to the digester 12 is fermented in the digester 12 to generate methane. The fermented processing liquid is supplied to a final dehydrator (not shown) and dehydrated to form a sludge cake, which is processed by an appropriate method. The separation liquid separated by the centrifugal dehydrator 8 and the final dehydrator is collected in, for example, a separation liquid treatment tank (not shown) and mixed into the sewage flowing into the first precipitation tank 2. Has been. A part of the methane generated in the digestion tank 12 is utilized as a fuel for heating the adjusted concentrated sludge in the pretreatment tank 11.

  Hereinafter, the operation mode of the sludge treatment facility 1 ′ having the above configuration will be described. That is, in the sludge treatment facility 1 ′, a first crusher (for example, a macerator pump) 6 that makes a solid substance smaller particles is disposed on the upstream side of the centrifugal dehydrator 8. Therefore, it is crushed into small particles by crushing the residue such as hair and vinyl pieces in the residue containing sludge by the crushing blade of the first crusher 6 and supplied to the sludge inlet of the centrifugal dehydrator 8. There is no fear that the sludge inlet will be clogged with residue. Therefore, since the residue-containing sludge is stably and continuously concentrated, the concentrated sludge is stably pretreated and digested on the subsequent stage side.

  In the above embodiment, the first sludge return line 6a communicates from the first crusher 6 to the upper part of the receiving tank 5, and the second sludge return line 9a communicates from the lower part of the adjustment tank 10 to the second crusher 9. The example in which the residue-containing sludge or the residue-containing concentrated sludge is circulated is described. However, even if the first sludge return line 6a and the second sludge return line 9a are not provided, a certain effect can be obtained, and the dehydrator is not limited to the centrifugal dehydrator. For example, a screw press (for example, Japanese Patent Application Laid-Open No. 2004-195524). The technical idea of the present invention can also be applied to a rotary pressure dehydrator (for example, those described in JP-T-2004-532733). The configuration is not limited to the equipment 1 '. Further, the sludge treatment facility 1 ′ according to the above embodiment is only one specific example of the present invention, and therefore, design changes and the like can be freely made without departing from the technical idea of the present invention.

It is typical structure explanatory drawing of the sludge processing equipment which concerns on the form of this invention. It is the schematic of the sludge processing equipment which concerns on the prior art example 1. It is the schematic of the sludge processing equipment concerning the prior art example 2. It is the schematic of the purification apparatus of the sludge treatment facility which concerns on the prior art example 2. It is sectional drawing of the typical centrifugal dehydrator which concerns on a prior art example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Sewage treatment equipment, 1 '... Sludge treatment equipment, 2 ... First sedimentation tank, 3 ... Aeration tank, 4 ... Final sedimentation tank, 5 ... Receiving tank, 6 ... 1st crusher, 6a ... 1st sludge return line, 7 ... Pump, 8 ... Centrifugal dehydrator. DESCRIPTION OF SYMBOLS 9 ... 2nd crusher, 9a ... 2nd sludge return line, 10 ... Adjustment tank, 11 ... Pretreatment tank, 12 ... Digestion tank.

Claims (4)

  The 1st crusher which crushes the solid substance in the residue containing sludge into smaller particles, the dehydrator which accepts and concentrates the residue containing sludge crushed by this 1st crusher, and was dehydrated by this dehydrator Fermenting the second crusher that receives and crushes the concentrated sludge, the pretreatment tank that accepts the concentrated sludge crushed by the second crusher and facilitates digestion, and the pretreatment liquid pretreated in this pretreatment tank A sludge treatment facility characterized by comprising a digester for generating methane.   2. The sludge return line communicating with the receiving tank from the first crusher is provided on the upper stage side of the first crusher, and a receiving tank is provided for receiving sludge containing sludge. Sludge treatment equipment.   An adjustment tank is provided between the second crusher and the pretreatment tank to make the concentration of solids in the concentrated sludge crushed by the second crusher uniform from the adjustment tank to the second crusher. 3. The sludge treatment facility according to claim 2, further comprising a sludge return line communicating with the sludge.   A sludge treatment method, comprising treating sludge containing sludge using the sludge treatment facility according to any one of claims 1 to 3.