JP2011230019A - Control system, control device and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system, control device, and control method for a concentrator and a dehydrator, which make dewaterability of concentrated sludge discharged from the dehydrator constant by controlling the concentrator, a concentrated sludge feed pump, and the dehydrator.SOLUTION: The control system includes the concentrator 101 where flocculated sludge obtained by coagulating a sludge stock solution with a polymer flocculant and agitating it and supplied at a constant flow rate is filtered to generate the concentrated sludge, a liquid level measuring device 102 which temporarily stores the concentrated sludge and measures the liquid level of the stored concentrated sludge, the concentrated sludge feed pump 103 which discharges the concentrated sludge, a pressure gauge 104 which measures the pressure of the concentrated sludge, the dehydrator 105 which dehydrates the concentrated sludge supplied from the concentrated sludge feed pump 103 under pressure, and the control device 106 which controls the concentrator 101, the concentrated sludge feed pump 103, and the dehydrator 105 based on the liquid level measured by the liquid level measuring device 102, the number of revolutions of the concentrated sludge feed pump 103, and press-in pressure of the concentrated sludge to the dehydrator 105 measured by the pressure gauge 104.

Description

  The present invention relates to a concentration apparatus and a control system for the dehydration apparatus, a control apparatus and a method for continuously concentrating and dewatering a sludge stock solution having a constant flow rate.

  Conventionally, a polymer flocculant is added to organic sludge such as sewage, human waste, or food production processing wastewater, and the mixture is stirred and mixed in a coagulation tank to generate coagulated flocs. When organic sludge with low concentration is concentrated and dehydrated directly with a dehydrator, the sludge concentration is low on the sludge injection side of the dehydrator, so the outer cylinder screen in the concentration zone has a greater water load than the solid load, A large amount of water is discharged. Therefore, in order to reduce the water load caused by the dewatering device, a method of further concentrating the aggregated floc with a concentrating device and performing filtration dewatering is employed. In these concentrators, for example, 1% of sludge is concentrated to 4 to 5%, and this concentrated sludge is filtered and dehydrated by a dehydrator.

  Here, as a concentrating device, there has been proposed a rotary concentrator for concentrating while rotating a screw shaft provided in an outer cylinder screen and regenerating a filtration surface that is easily clogged (see, for example, Patent Document 1). In addition, as a dewatering device, a cylindrical screen and a screw shaft that can rotate freely inside are provided. In this dewatering device that separates solid and liquid while conveying concentrated sludge by driving rotation of this screw shaft, sludge and the like are supplied to this dewatering device. Concentrated sludge supply pump and a pressure detector that detects the press-fitting pressure of the concentrated sludge supplied to the dehydrator, and supply of the concentrated sludge feed pump so that the press-fitting pressure detected by the pressure detector is almost constant A method for controlling the flow rate has also been proposed (see, for example, Patent Document 2). Furthermore, as a method of controlling the concentrated sludge concentration of a differential speed rotary concentrator that concentrates sludge while rotating the outer cylinder screen and screw shaft at a differential speed, a power detector is installed in the sludge receiving tank of the concentrated sludge to detect the power. There has also been proposed a technique for controlling the flocculant addition rate, screw shaft rotation speed, and outer cylinder screen rotation speed by discriminating the electrical signal of the concentrated sludge concentration detected by the vessel (for example, Patent Document 3). Furthermore, a flocculation mixing tank with a concentration function and a standard flocculation mixing tank are arranged in series, and a constant flow of sludge stock solution is supplied to the flocculation mixing tank with a concentration function, and the pressure of the concentrated sludge to be injected into the dehydrator is reduced. Adjusting the sludge concentration of the concentrated sludge by changing the flocculant addition rate of the polymer flocculant added to the coagulation mixing tank with the concentration function as the tank internal pressure of the coagulation mixing tank with the concentration function changes, while keeping it constant. There has also been proposed a technique for adjusting the amount of solids to be treated with a constant press-fitting pressure in an agglomeration mixing tank before being supplied to a dehydrator (for example, Patent Document 4).

JP 2003-181216 A JP 2008-55450 A JP 2006-289308 A JP 2007-136347 A

  Usually, when dewatering concentrated sludge, the sludge concentrated by the concentrating device is once put in a storage tank, and then used as a stock solution to re-aggregate and dehydrate. In this case, the sludge is retained in the concentrated sludge storage tank for a long time due to the processing procedure and time constraints, and as a result, the decay of the concentrated sludge proceeds. Therefore, not only does the dewatering efficiency of the concentrated sludge not increase, but conversely, a phenomenon such as a decrease in dewaterability may occur. Therefore, when dewatering concentrated sludge, it is desirable to dehydrate immediately after concentration. Moreover, in order to dehydrate after concentration, not only a concentration device and a dehydration device but also a concentrated sludge storage tank was required, and a large installation area was required.

  The conventional dehydrator can prevent overload and obtain a cake with a uniform moisture content by controlling the rotational speed of the screw shaft for sludge with good filterability. For sludge, if the volume of the filtration chamber is reduced and compressed and dehydrated, the filtration surface of the outer cylinder screen is clogged at an early stage. Or if it squeezes rapidly, sludge will be discharged | emitted from an outer cylinder screen with a filtrate, and there exists a possibility that a filtrate may be suspended. In the conventional operation control method of the dehydrator, the supply flow rate of the stock solution supply pump is controlled to control the supply flow rate of the stock solution supplied to the dehydrator in order to control the press-fitting pressure of the stock solution to be dehydrated. To do. However, in practice, the amount of processing varies depending on the concentration of the stock solution and the dehydration. For example, the supply flow rate increases when the stock solution concentration is low, and the supply flow rate decreases when the stock solution concentration is high. Therefore, there is a problem that the supply flow rate fluctuates.

  In addition, in the differential speed rotary concentrator, the technology to control the flocculant addition rate, screw shaft rotation speed and outer cylinder screen rotation speed to keep the concentrated sludge concentration constant, the sludge concentration after concentration is stable, Management of processing steps is facilitated. However, fluctuations in the sludge properties cause variations in the amount of concentrated sludge, making it difficult to ensure continuity in the processing amount between the concentration device and the dewatering device connected to the concentration device. When temporarily storing the concentrated sludge, a concentrated sludge storage tank is required, and a large installation area is required. In addition, the control method of the dehydrator with a coagulation / mixing tank with a concentration function installed upstream of the standard coagulation / mixing tank is a coagulation / mixing system with a concentration function for fluctuations in the raw sludge concentration and the solids throughput of the raw liquid sludge. While detecting the tank internal pressure of the tank and the coagulation mixing tank and maintaining the tank internal pressure of the coagulation mixing tank constant, the concentration rate is adjusted by adjusting the amount of polymer flocculant added to the coagulation mixing tank with the first stage concentration function. By improving and improving the dewaterability, the load on the dehydrator is equalized.

  However, in a flocculation / mixing tank with a concentration function, concentration within 1.5 to 2 times is at most a normal operation range, so there is a limit to the ability to cope with rapidly changing sludge concentration and sludge properties.

  In view of the above problems, the present invention controls a control system for controlling the screw shaft of a dewatering device connected downstream of the concentrating device and the concentrating device in order to control to concentrate and dehydrate the sludge stock solution at a constant flow rate continuously. An object is to provide an apparatus and method.

  In order to achieve the above object, one aspect of the present invention is as follows. (A) A concentrating device for producing a concentrated sludge by filtering the agglomerated sludge supplied with a constant flow rate by agglomerating and stirring the sludge stock solution with a polymer flocculant. And (b) a liquid level measuring device that temporarily stores the concentrated sludge discharged by the concentrating device and measures the position of the stored concentrated sludge, and (c) the concentrated sludge that is temporarily stored by the liquid level measuring device. (D) a pressure gauge that measures the pressure of the concentrated sludge discharged from the concentrated sludge supply pump, and (e) a dehydrator that dehydrates the concentrated sludge that is press-fitted from the concentrated sludge supply pump. (F) Based on the liquid level measured by the liquid level measuring device, the rotation speed of the concentrated sludge supply pump, and the pressure applied to the dehydrator by the concentrated sludge measured by the pressure gauge, the concentrator, the concentrated sludge supply pump and the dehydrator Control device to control And summarized in that provided.

  Another aspect of the present invention is that a sludge concentrate is agglomerated and agitated by a polymer flocculant, the agglomerated sludge supplied at a constant flow rate is filtered to produce a concentrated sludge, and a concentrated sludge discharged from the concentrator. Liquid level measuring device that temporarily stores and measures the position of the stored concentrated sludge, concentrated sludge supply pump that discharges the concentrated sludge temporarily stored by the liquid level measuring device, and concentrated sludge supply pump discharged The present invention relates to a control device that controls a pressure gauge that measures the pressure of concentrated sludge and a dewatering device that dehydrates concentrated sludge that is press-fitted and supplied from a concentrated sludge supply pump. That is, the control device according to the aspect of the present invention is based on the liquid level measured by the liquid level measuring device, the rotational speed of the concentrated sludge supply pump, and the press-fitting pressure into the dewatering device by the concentrated sludge measured by the pressure gauge. The gist is to control the concentrated sludge supply pump and the dewatering device.

  According to still another aspect of the present invention, there is provided a step (a) in which the concentrating device is configured to agglomerate and stir the sludge stock solution with the polymer flocculant, filter the agglomerated sludge supplied at a constant flow rate, and generate the concentrated sludge; (B) a step in which the liquid level measuring device temporarily stores the concentrated sludge discharged from the concentrator and measures the position of the stored concentrated sludge; and (c) the concentrated sludge supply pump is temporarily in the liquid level measuring device. The concentrated sludge stored in the tank, (d) the pressure gauge measures the pressure of the concentrated sludge discharged by the concentrated sludge supply pump, and (e) the dehydrator press-fits from the concentrated sludge supply pump. The step of dewatering the concentrated sludge and the (f) control device adjust the liquid level measured by the liquid level measuring device, the rotational speed of the concentrated sludge supply pump, and the pressure applied to the dewatering device by the concentrated sludge measured by the pressure gauge. Based on the concentrator , The gist of that and controlling the concentrated sludge feed pump and a dehydrator.

  According to the present invention, there is provided a control system, a control device and a method for controlling a screw shaft of a dewatering device connected downstream of the concentrating device and the concentrating device in order to control to concentrate and dehydrate the sludge stock solution at a constant flow rate continuously. Can be provided.

It is a block diagram of a control system concerning an embodiment of the invention. It is the schematic of the apparatus structure of the control system which concerns on embodiment of this invention. It is sectional drawing of the concentration apparatus which concerns on embodiment of this invention. It is sectional drawing of the spin-drying | dehydration apparatus which concerns on embodiment of this invention. It is the schematic in the concentrated sludge supply side of the spin-drying | dehydration apparatus which concerns on embodiment of this invention. It is the schematic on the concentrated sludge discharge | emission side of the dehydration apparatus which concerns on embodiment of this invention. It is a flowchart figure of the control method which concerns on embodiment of this invention. It is a flowchart figure of the control method which concerns on embodiment of this invention. It is a flowchart figure of the control method which concerns on the modification of embodiment of this invention.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and the configuration of the apparatus and system is different from the actual one. Therefore, a specific configuration should be determined in consideration of the following description. In addition, it is a matter of course that portions having different configurations are included between the drawings.

  The following embodiments of the present invention exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is the material and shape of the component parts. The structure, arrangement, etc. are not specified as follows. The technical idea of the present invention can be variously modified within the technical scope described in the claims.

(Embodiment)
<Functional configuration of control system>
As shown in FIG. 1, the control system according to the embodiment of the present invention concentrates and agitates sludge stock solution with a polymer flocculant, filters the agglomerated sludge supplied at a constant flow rate, and generates concentrated sludge. The apparatus 101, the concentrated sludge discharged from the concentrating apparatus 101 are temporarily stored, the liquid level measuring apparatus 102 that measures the position of the stored concentrated sludge, and the concentrated sludge temporarily stored by the liquid level measuring apparatus 102 are stored. Concentrated sludge supply pump 103 to be discharged, pressure gauge 104 for measuring the pressure of the concentrated sludge discharged from the concentrated sludge supply pump 103, dehydrator 105 for dewatering the concentrated sludge that is press-fitted and supplied from the concentrated sludge supply pump, and liquid level Based on the liquid level of the concentrated sludge measured by the measuring device 102, the rotation of the concentrating screw shaft of the concentrating device 101 and the press-fitting pressure of the concentrated sludge measured by the pressure gauge 104 Based on the rotational speed of the fine concentrated sludge supply pump 103, and a control unit 106 for controlling the rotation of the dewatering screw shaft dehydrator 105 has.

  The concentrator 101 concentrates the sludge stock solution so as to have a predetermined sludge concentration.

  The liquid level measurement device 102 temporarily stores the concentrated sludge discharged continuously from the concentration device 101, and detects, detects, and measures the liquid level of the stored concentrated sludge. The liquid level of the concentrated sludge is due to fluctuations in the sludge properties, for example, the influence of the filterability of the concentrated sludge. The sludge liquid level rises due to the decrease in filterability.

  The concentrated sludge supply pump 103 applies pressure to the concentrated sludge in the flow direction so that the concentrated sludge discharged from the liquid level measuring device 102 is discharged at a flow rate higher than the supplied flow rate.

  The pressure gauge 104 measures the pressure of the concentrated sludge discharged from the concentrated sludge supply pump 103 at a supply port of the dehydrator 105 described later.

  The dehydrator 105 lowers the moisture content by squeezing water from the concentrated sludge.

Dehydrated by filtering the concentrated sludge. As the dehydrating apparatus 105, a screw press, an impeller rotary pressurizing dehydrator, a belt press, a vacuum dehydrator, and a centrifugal dehydrator can be applied. The dehydrating apparatus 105 according to the embodiment of the present invention uses an outer cylinder rotating type screw press.

  The control device 106 controls the rotation speed of the screw shaft included in the concentrating device 101 based on the liquid level of the concentrated sludge measured by the liquid level measuring device 102. In addition, the control device 106 controls the rotation speed of the concentrated sludge supply pump 103 based on the pressurization pressure of the concentrated sludge at the supply port of the dehydrator 105 measured by the pressure gauge 104, and further the rotation speed of the concentrated sludge supply pump 103. Based on the above, the rotational speed of the screw shaft included in the dehydrating apparatus 105 is controlled.

  That is, the control device 106 compares the measured sludge liquid level that is the liquid level of the concentrated sludge measured by the liquid level measuring device 102 with a preset reference liquid level range. Based on the result of the comparison (based on the relationship between the liquid level of the concentrated sludge and the reference liquid level range), the control device 106 determines the value of the concentration device control coefficient α. Here, α is a control parameter for appropriately adjusting the rotational speed of the screw shaft of the concentrator 101 and the rotational speed of the concentrated sludge supply pump 103. The sludge liquid level, the concentrated sludge pressure at the supply port of the dehydrator 105 And empirically determined based on the properties of concentrated sludge.

  That is, when the liquid level of the concentrated sludge is higher than the reference liquid level range, the value of α is increased, and when the liquid level of the concentrated sludge is within the reference liquid level range, the value of α is not changed, When the liquid level is lower than the reference liquid level range, the value of α is decreased. Subsequently, the control device 106 is a value obtained by multiplying α by a measurement pump rotation speed that is the rotation speed of the concentrated sludge supply pump 103 and a pump reference rotation speed range that is a preset reference rotation speed of the concentrated sludge supply pump. Compare with the α reference speed range. Based on the comparison result, the control device 106 increases the rotation speed of the concentrating screw shaft included in the concentrating device 101 when the measurement pump rotation speed is larger than the α reference rotation speed range, and the measurement pump rotation speed is set to the α reference rotation. When the rotation speed is within the range, the rotation speed of the concentration screw shaft included in the concentration apparatus 101 is maintained. When the rotation speed of the measurement pump is smaller than the α reference rotation speed range, the rotation speed of the concentration screw shaft included in the concentration apparatus 101 is increased. Decrease.

  Here, the control of the concentrating device 101 is based on the following logic. When the rotational speed of the screw shaft included in the concentrating device 101 is increased, the conveying speed by the screw blades is increased in the filtration chamber, the amount of concentrated sludge is increased, and when the rotational speed of the screw shaft included in the concentrating device 101 is decreased, As a result, the conveying speed by screw blades is reduced, and the amount of concentrated sludge is reduced.

  Next, the control device 106 compares the measured press-fit pressure, which is the press-fit pressure at the supply port of the dehydrator 105 measured by the pressure gauge 104, with a preset reference press-fit pressure range. Here, the reference press-fit pressure range is an empirical value suitable for realizing an appropriate sludge treatment. Based on the comparison result, the control device 106 decreases the rotation speed of the concentrated sludge supply pump 103 when the measured press-fit pressure is larger than the reference press-fit pressure range, and the measured press-fit pressure is within the reference press-fit pressure range. When the rotation speed of the concentrated sludge supply pump 103 is maintained and the measured press-fitting pressure is smaller than the reference press-fit pressure range, the rotation speed of the concentrated sludge supply pump 103 is increased.

  Subsequently, the control device 106 compares the measurement pump rotation speed, which is the rotation speed of the concentrated sludge supply pump 103, with a preset pump reference rotation speed range. Based on the result of the comparison, when the measurement pump rotation speed is larger than the reference rotation speed range, the control device 106 decreases the rotation speed of the dewatering screw shaft included in the dehydration apparatus 105 and the measurement pump rotation speed is within the reference rotation speed range. If the rotation speed is within the range, the rotation speed of the dehydration screw shaft included in the dehydration apparatus 105 is maintained. If the rotation speed of the measurement pump is smaller than the reference rotation speed range, the rotation speed of the dehydration screw shaft included in the dehydration apparatus 105 is increased.

  As described above, the liquid level measurement in which the concentrated sludge mixed and stirred with the sludge stock solution and the polymer flocculant supplied to the control system at a constant flow rate is concentrated by the concentrator 101 and temporarily stored. The control device 106 controls the concentration device 101 so that the concentration sludge liquid level of the device 102 becomes constant. That is, the control device 106 controls the rotation speed of the concentration screw shaft included in the concentration apparatus 101 based on the measurement result of the liquid level measurement apparatus 102 and the rotation speed of the concentrated sludge supply pump 103. In addition, the control device 106 controls the concentrated sludge supply pump 103 so that the press-fitting pressure of the concentrated sludge supplied to the dehydrator 105 by the concentrated sludge supply pump 103 is constant, and the concentrated sludge supply pump The control device 106 controls the dehydrating device 105 so that the number of rotations 103 becomes constant. That is, the control device 106 controls the rotation speed of the concentrated sludge supply pump 103 based on the measurement result of the pressure gauge 104, and the dehydration screw shaft included in the dewatering device 105 based on the rotation speed of the concentrated sludge supply pump 103. Control the number of revolutions.

  Accordingly, the control device 106 independently determines the rotation speed of the concentrating screw shaft included in the concentrating device 101 and the rotation speed of the dehydrating screw shaft included in the dehydrating device 105 based on the measurement results of the liquid level measuring device 102 and the pressure gauge 104. Control.

<Device configuration of control system>
Next, the equipment configuration of the control system according to the embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 2, the control system 100 agglomerates the processing stock solution such as sludge stored in a sludge storage tank (not shown) through the stock solution supply pipe 2 at the stock solution flow rate (supply flow rate) by the stock solution supply pump 1. Supplied to the device 3. The stock solution supply pipe 2 is connected to a coagulant supply pipe 5 of a polymer supply pump 4 that supplies the polymer coagulant. Note that the flocculant supply pipe 5 can be directly connected to the aggregating apparatus 3. The polymer flocculant is supplied at a constant ratio with respect to the stock solution flow rate, and the rotation speed of the polymer supply pump 4 is proportionally controlled by the control device 60 together with the rotation speed of the stock solution supply pump 1.

  The agglomeration device 3 is configured to agitate and mix sludge and polymer flocculant supplied from the stock solution supply pump 1 and the polymer supply pump 4 to the agglomeration device 3 with an agitator to generate agglomeration floc. The undiluted solution and the polymer flocculant that flowed into 6 are stirred by a stirring blade 8 that is rotationally driven by a stirring drive 7. The agglomerated sludge stirred and agglomerated by the aggregating device 3 is supplied to the concentrator 10 through the agglomerated sludge supply pipe 9.

  Note that the concentrating device 101, the liquid level measuring device 102, the concentrated sludge supply pump 103, the pressure gauge 104, the dewatering device 105, and the control device 106 shown in FIG. 1 are arranged in the concentrator 10 and the concentrated sludge pipe 26 shown in FIG. This corresponds to the liquid level gauge 28, the concentrated sludge supply pump 27, the pressure gauge PS, the dehydrator 30, and the control device 60, respectively.

<Equipment configuration of concentrator>
The concentrator according to the embodiment of the present invention applies a rotary concentrator. As shown in FIG. 3, the rotary concentrator 11 is provided with a screw shaft 14 around which screw blades 13 are wound inside an outer cylinder screen 12 having a filtration surface on the periphery. An inlet flange 15 and an outlet flange 16 are fitted to the end of the outer cylinder screen 12. An inlet flange 15 is pivotally supported on the screw shaft 14, and an outer cylinder drive shaft 17 connected to the outlet flange 16 is pivotally supported on a bearing 19 that is supported on a filtrate receiving tank 18. A screw drive shaft 20 connected to the screw shaft 14 is inserted into the outer cylinder drive shaft 17.

  A sludge supply path 21 is provided at the tip of the screw shaft 14, a plurality of supply ports 21 a are opened at the start end of the outer cylinder screen 12, and a plurality of discharge ports 16 a are provided at the outlet flange 16. A filtration chamber 22 is formed between the outer cylinder screen 12 and the screw shaft 14. An outer cylinder driving machine 23 and a screw driving machine 24 are individually linked to the outer cylinder driving shaft 17 of the outer cylinder screen 12 and the screw driving axis 20 of the screw shaft 14, and the outer cylinder screen 12 and the screw shaft 14 are connected to each other. Rotate the motor in the opposite direction. The rotary concentrator 11 separates sludge supplied from the supply path 21 of the screw shaft 14 to the filtration chamber 22 from the filtrate through the outer tube screen 12 while rotating the outer tube screen 12 and the screw shaft 14 in the reverse direction. The sludge concentrated by the rotary concentrator 11 is discharged from the outlet 16 a of the outlet flange 16.

  By rotating the outer cylinder screen 12 and the screw shaft 14 at a differential speed, the rotational speed of the screw blade 13 is relatively increased, and the number of sliding contact of the filtration surface of the outer cylinder screen 12 is increased. The rotary concentrator 11 regenerates the filtration surface of the outer cylinder screen 12 that is clogged during operation, thereby promoting the discharge of the filtrate and realizing a large amount of sludge treatment with a low concentration. The cleaning water pipe 25 shown in FIG. 3 is disposed along the outer cylinder screen 12, and jets high-pressure water onto the clogged outer cylinder screen 12 to eliminate clogging of the filtration surface. Further, by supplying a part of the filtrate separated and discharged to the filtrate receiving tank 18 into the concentrated sludge pipe 26, bridge of the concentrated sludge in the concentrated sludge pipe 26 is prevented, and the concentrated sludge supply pump 27 is supplied smoothly. It becomes possible.

  The concentrated sludge from which the filtrate has been separated by the rotary concentrator 11 is supplied to the concentrated sludge supply pump 27 via the concentrated sludge pipe 26. The concentrated sludge pipe 26 has a volume capable of storing the concentrated sludge discharged from the rotary concentrator 11 with a predetermined capacity, and a liquid level meter 28 for measuring the storage amount is provided. The concentrated sludge is press-fitted and supplied to the dehydrator 30 through the concentrated sludge supply pipe 29 by the concentrated sludge supply pump 27. The concentrated sludge supply pipe 29 is provided with a pressure gauge PS for measuring the press-fitting pressure of the concentrated sludge that is press-fitted and supplied to the dehydrator 30.

<Equipment configuration of dehydrator>
The dehydrating apparatus according to the embodiment of the present invention uses a screw press capable of continuously dewatering concentrated sludge. The screw press 31 mounts the rotary concentrator 11 in the vicinity. For example, a concentrated sludge pipe 26 standing on the discharge side of the rotary concentrator 11 is disposed, a concentrated sludge supply pump 27 is disposed on the discharge side of the concentrated sludge pipe 26, and a screw is disposed on the discharge side of the concentrated sludge supply pump 27. A press 31 is disposed. Since the concentrating device is mounted on the dehydrating device, it is not necessary to retain the concentrated sludge in the storage tank for a long time, and the dehydrating effect due to rot does not decrease. In addition, a large installation area for the concentrator, the concentrated sludge storage tank, and the dewatering equipment is not required. Therefore, if it is installed in wastewater treatment facilities such as sewage, human waste treatment, village drainage, and factories, it becomes a space-saving concentrated water-saving facility.

  As shown in FIG. 4, the screw press 31 has a screw shaft 34 in which a screw blade 33 is wound around an outer cylinder screen 32 having a filtration surface on the periphery. The screw shaft 34 expands in the vertical direction from the sludge supply side to the cake discharge side, and the filtration chamber 35 between the outer cylinder screen 32 and the screw shaft 34 extends from the supply side to the discharge side. Reduce in the vertical direction on the page.

  The configuration on the supply side of the screw press 31 will be described with reference to FIG. The screw press 31 has a sprocket 37 externally fitted to an inlet flange 36 fitted to the supply side of the outer cylinder screen 32, and is interlocked and connected to an outer cylinder drive 39 that can be rotated forward and backward. The screw shaft 34 is provided with a supply path 41 for agglomerated slurry. A supply hole 41 a is opened at the start end of the filtration chamber 35, and the extended portion of the screw shaft 34 and the concentrated sludge supply pipe 29 are connected. Concentrated sludge that is press-fitted into the filtration chamber 35 from the supply hole 41a is supplied from between the screw blades 33 wound around the screw shaft 34, and concentrated sludge such as agglomerated soft sludge is screw blades. It is arranged so as not to be affected by 33.

  The configuration on the discharge side of the screw breath 31 will be described with reference to FIG. In the screw press 31, a rotating plate 42 connected to the discharge side of the outer cylinder screen 32 is supported on a frame 43, and a screw drive shaft 44 is connected to a screw shaft 34 provided in the outer cylinder screen 32. A back pressure adjusting presser 45 provided to the discharge port 35 a of the filtration chamber 35 is slidably supported on a moving shaft 46 disposed on the frame 43.

  As shown in FIG. 3, the screw drive shaft 44 connected to the screw shaft 34 is pivotally supported by a bearing 49 provided on a frame 48 of the frame 43. A sprocket 50 is fitted on the screw drive shaft 44 and interlocked with a screw drive machine 51 placed on the frame 43. The screw driver 51 of the screw shaft 34 is operated, the concentrated sludge is supplied from the supply part 41 of the screw shaft 34 to the filtration chamber 35, and the filtrate is separated from the outer cylinder screen 32 while the concentrated sludge is transferred by the screw blades 33. .

  The opening amount of the discharge port 35a of the filtration chamber 35 is adjusted by the presser 45, and solid-liquid separation is promoted while applying back pressure to the filtration chamber 35 to discharge the dehydrated cake. A cleaning pipe 52 is disposed along the outer cylinder screen 32. During cleaning, cleaning water is sprayed from the cleaning pipe 52 onto the outer cylinder screen 32, and the outer cylinder screen 32 is rotated by an outer cylinder driving device 39 so that the outer cylinder screen 32 rotates. The entire surface of the tube screen 32 is cleaned. In addition, a filtrate trough 53 is disposed below the outer cylinder screen 32, and a cake receiving tank for receiving dehydrated cake is disposed adjacent to the filtrate trough 53 at the end of the screw press 31.

<Operation control method in sludge treatment of control system>
Next, a method for controlling the concentrating device 101 and the dehydrating device 105 by the control system according to the embodiment of the present invention will be described with reference to the flowcharts of FIGS. As shown in FIG. 1, the control system 100 performs control so that the press-fitting pressure due to the concentrated sludge to the dewatering device 105 is constant in the path from the concentration device 101 to the dewatering device 105. The control device 106 controls the rotation of the screw shaft included in the concentrating device 101 and the rotation of the concentrated sludge supply pump 103 so as to maintain a predetermined number of rotations, and adjusts the flow rate of the concentrated sludge to be constant. . In addition, as shown in FIG. 1, the control system 100 performs control so that the flow rate of the concentrated sludge is constant in the path from the concentrated sludge supply pump 103 to the dehydrator 105. The control device 106 controls the rotation of the concentrated sludge supply pump 103 and the rotation of the screw shaft included in the dewatering device 105 so as to maintain a predetermined rotation speed, and adjusts the pressure of the concentrated sludge to be constant. To do. As a result, the dewatered sludge discharged from the dewatering device 105 is generated as a high-quality sludge cake with constant dewaterability.

  First, the control device 106 controls the screw shaft of the concentration device 101 so that the flow rate of the concentrated sludge flowing into the concentrated sludge supply pump 103 shown in FIG.

  (A) In step S101, the control device 106 compares the measured sludge liquid level, which is the liquid level of the concentrated sludge measured by the liquid level measuring device 102, with a preset reference liquid level range. Here, the reference liquid level range is a liquid level in which the concentrated sludge discharged from the concentrator 101 is temporarily stored, and the system is controlled even if the concentrator 101, the concentrated sludge supply pump 103, and the dehydrator 105 are controlled. It is the range of the liquid level that can be operated without any problems as a whole. In step S101, when the measured sludge liquid level is higher than the reference liquid level range, in step S102, the control device 106 increases the value of the concentration device control coefficient α. In step S101, when the measured sludge liquid level is within the reference liquid level range, in step S103, the control device 106 maintains the value of the concentration device control coefficient α. In step S101, when the measured sludge liquid level is lower than the reference liquid level range, in step S104, the control device 106 decreases the value of the concentrator control coefficient α.

  (B) In step S105, the control device 106 concentrates the measuring pump rotation speed, which is the rotation speed of the concentrated sludge supply pump 103, and a pump reference rotation speed range, which is a preset reference rotation speed of the concentrated sludge supply pump 103. An α reference rotation speed range that is a value obtained by multiplying the control coefficient α is compared. In step S105, when the rotation speed of the concentrated sludge supply pump 103 is larger than the α reference rotation speed range, the control apparatus 106 increases the rotation speed of the concentration screw shaft included in the concentration apparatus 101 in step S106. If the rotation speed of the concentrated sludge supply pump 103 is within the α reference rotation speed range in step S105, the control device 106 maintains the rotation speed of the concentration screw shaft included in the concentration apparatus 101 in step S107. In step S105, when the rotation speed of the concentrated sludge supply pump 103 is smaller than the α reference rotation speed range, the control apparatus 106 decreases the rotation speed of the concentration screw shaft included in the concentration apparatus 101 in step S108.

  Next, the control device 106 controls the dewatering screw shaft of the dewatering device 105 so that the press-fitting pressure of the concentrated sludge flowing into the dewatering device 105 shown in FIG. 1 becomes constant.

  (A) In step S201, the control device 106 compares the measured press-fitting pressure, which is the press-fitting pressure of the concentrated sludge measured by the pressure gauge 104, with a preset reference press-fitting pressure range. Here, the reference press-fitting pressure range is a press-fitting pressure to the dehydrating device 105 by the concentrated sludge measured by the pressure gauge 104, and is a pressure range in which the dehydrating efficiency by the dehydrating device 105 is the best. In step S201, when the measured press-fit pressure is larger than the reference press-fit pressure range, in step S202, the control device 106 decreases the rotation speed of the concentrated sludge supply pump 103. In step S201, when the measured press-fit pressure is within the reference press-fit pressure, in step S203, the control device 106 maintains the rotation speed of the concentrated sludge supply pump 103. In step S201, when the measured press-fit pressure is smaller than the reference press-fit pressure range, in step S204, the control device 106 increases the rotation speed of the concentrated sludge supply pump 103.

  (B) In step S205, the control device 106 compares the measurement pump rotation speed, which is the rotation speed of the concentrated sludge supply pump 103, with a preset pump reference rotation speed range. In step S205, when the measurement pump rotational speed is larger than the pump reference rotational speed range, in step S206, the control device 106 decreases the rotational speed of the dehydrating screw shaft included in the dehydrating apparatus 105. In step S205, when the measurement pump rotation speed is within the pump reference rotation speed range, in step S207, the control device 106 maintains the rotation speed of the dehydrating screw shaft included in the dehydrating apparatus 105. In step S205, when the measurement pump rotation speed is smaller than the pump reference rotation speed range, in step S208, the control device 106 increases the rotation speed of the dehydration screw shaft included in the dehydration apparatus 105.

  As described above, the control system according to the embodiment of the present invention controls the rotational speed of the concentrated sludge supply pump 103 based on the press-fitting pressure of the dewatering device (screw press) 105. The filtration dehydration pressure can be controlled to be constant at all times, and a stable dehydration operation is possible. Further, the control system sets a reference value in advance for the rotation speed of the concentrated sludge supply pump 103, and based on the reference value, the rotation speed of the dewatering screw shaft included in the dewatering device (screw press) 105 and the concentration included in the concentrating device 101. Since the number of rotations of the screw shaft is controlled independently and in parallel, the processing flow rate can be stabilized as a whole control system. In addition, the above-mentioned reference value can set the range suitable for each screw shaft of the dehydrating apparatus 105 and the concentrating apparatus 101 independently.

  Further, by installing the dehydrator 105 and the concentrator 101 close to each other, the reaction to the press-fitting pressure by the dehydrator 105 is quick, it is possible to respond quickly to changes in the press-in pressure, and the stability of the constant process is improved. Furthermore, the concentrating device 101 and the dewatering device 105 are installed close to each other, and the concentrated sludge is continuously circulated, so that a storage tank for storing the concentrated sludge is not required upstream of the dewatering device 105. In addition, since the liquid level of the concentrated sludge temporarily stored in the liquid level measuring device 102 is also controlled, it is possible to prevent the dehydration device 105 from being idle and overflowing due to the concentrated sludge from the liquid level measuring device (hopper) 102. it can.

  In this way, by keeping the internal pressure of the dewatering device 105 constant, the dewaterability of the concentrated sludge can be made constant and a high quality sludge cake can be produced.

(Modification of the embodiment)
A control system according to a modification of the embodiment of the present invention includes a control device 106 that controls the rotation speed of the outer cylinder screen 12 included in the concentration device 101 based on the liquid level of the concentrated sludge measured by the liquid level measurement device 102. Is provided. Since the control system according to the embodiment of the present invention includes the control device 106 that controls the rotation speed of the concentration screw shaft included in the concentration device 101 based on the liquid level of the concentrated sludge measured by the liquid level measurement device 102, The object to be controlled is different between the outer cylinder screen 12 and the concentration screw shaft. That is, the control device 106 compares the liquid level of the concentrated sludge measured by the liquid level measuring device 102 with a preset reference liquid level range. Based on the comparison result (by the relationship between the liquid level of the concentrated sludge and the reference liquid level range), the control device 106 controls the rotation speed of the outer cylinder screen 12 provided in the concentration device 101. That is, the control device 106 determines the value of the concentration device control coefficient α by comparing the measured sludge liquid level with the reference liquid level range. Subsequently, the control device 106 is a value obtained by multiplying α by a measurement pump rotation speed that is the rotation speed of the concentrated sludge supply pump 103 and a pump reference rotation speed range that is a preset reference rotation speed of the concentrated sludge supply pump. Compare with the α reference speed range. Based on the result of the comparison, when the measurement pump rotation speed is larger than the α reference rotation speed range, the control device 106 decreases the rotation speed of the outer cylinder screen 12 included in the concentrator 101 and the measurement pump rotation speed is set to the α reference. When the rotation speed is within the rotation speed range, the rotation speed of the outer cylinder screen 12 included in the concentration apparatus 101 is maintained. When the rotation speed of the measurement pump is smaller than the α reference rotation speed range, the rotation of the outer cylinder screen 12 included in the concentration apparatus 101 is maintained. Increase the number.

<Operation control method in sludge treatment of control system>
Next, a method for controlling the concentrating device 101 and the dehydrating device 105 by the control system according to the modification of the embodiment of the present invention will be described with reference to the flowchart of FIG.

<Operation control method in sludge treatment of control system>
Next, a method for controlling the concentrating device 101 and the dehydrating device 105 by the control system according to the modification of the embodiment of the present invention will be described with reference to the flowcharts of FIGS. As shown in FIG. 1, the control system 100 performs control so that the press-fitting pressure due to the concentrated sludge to the dewatering device 105 is constant in the path from the concentration device 101 to the dewatering device 105. The control device 106 controls the rotation of the outer cylinder screen 12 included in the concentration device 101 and the rotation of the concentrated sludge supply pump 103 so as to maintain a predetermined number of rotations, so that the flow rate of the concentrated sludge becomes constant. adjust. In addition, as shown in FIG. 1, the control system 100 performs control so that the flow rate of the concentrated sludge is constant in the path from the concentrated sludge supply pump 103 to the dehydrator 105. The control device 106 controls the rotation of the concentrated sludge supply pump 103 and the rotation of the screw shaft included in the dewatering device 105 so as to maintain a predetermined rotation speed, and adjusts the pressure of the concentrated sludge to be constant. To do. As a result, the dewatered sludge discharged from the dewatering device 105 is generated as a high-quality sludge cake with constant dewaterability.

  First, the control device 106 controls the outer cylinder screen 12 of the concentration device 101 so that the flow rate of the concentrated sludge flowing into the concentrated sludge supply pump 103 shown in FIG.

  (A) In step S301, the control device 106 compares the measured sludge liquid level, which is the liquid level of the concentrated sludge measured by the liquid level measuring device 102, with a preset reference liquid level range. Here, the reference liquid level range is a liquid level in which the concentrated sludge discharged from the concentrator 101 is temporarily stored, and the system is controlled even if the concentrator 101, the concentrated sludge supply pump 103, and the dehydrator 105 are controlled. It is the range of the liquid level that can be operated without any problems as a whole. In step S301, when the measured sludge liquid level is higher than the reference liquid level range, in step S302, the control device 106 increases the value of the concentrator control coefficient α. In step S101, when the measured sludge liquid level is within the reference liquid level range, in step S303, the control device 106 maintains the value of the concentrator control coefficient α. In step S301, when the measured sludge liquid level is lower than the reference liquid level range, in step S304, the control device 106 decreases the value of the concentration device control coefficient α.

  (B) In step S 305, the control device 106 concentrates the measuring pump rotation speed that is the rotation speed of the concentrated sludge supply pump 103 and the pump reference rotation speed range that is the preset reference rotation speed of the concentrated sludge supply pump 103. An α reference rotation speed range that is a value obtained by multiplying the control coefficient α is compared. When the rotation speed of the concentrated sludge supply pump 103 is larger than the α reference rotation speed range in step S305, the control device 106 decreases the rotation speed of the outer cylinder screen 12 included in the concentration apparatus 101 in step S306. If the rotation speed of the concentrated sludge supply pump 103 is within the α reference rotation speed range in step S305, the control apparatus 106 maintains the rotation speed of the outer cylinder screen 12 included in the concentration apparatus 101 in step S307. If the rotation speed of the concentrated sludge supply pump 103 is smaller than the α reference rotation speed range in step S305, the control device 106 increases the rotation speed of the outer cylinder screen 12 included in the concentration apparatus 101 in step S308.

  Next, the control device 106 controls the dewatering screw shaft of the dewatering device 105 so that the press-fitting pressure of the concentrated sludge flowing into the dewatering device 105 shown in FIG. 1 becomes constant. The description of this control is the same as described above and FIG.

(Other embodiments)
As mentioned above, although this invention was described by embodiment of this invention, it should not be understood that the statement and drawing which make a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. It goes without saying that the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

100 ... Control system 101 ... Concentrator,
102 ... Liquid level measuring device,
103 ... Concentrated sludge supply pump,
104 ... Pressure gauge,
105 ... dehydrator,
106 ... control device,

Claims (9)

A concentrating device for producing a concentrated sludge by filtering the agglomerated sludge, which is agglomerated and agitated by the polymer flocculant, and supplying the sludge stock solution at a constant flow rate;
A liquid level measuring device for temporarily storing the concentrated sludge discharged by the concentrator and measuring the position of the stored concentrated sludge;
A concentrated sludge supply pump for discharging the concentrated sludge temporarily stored by the liquid level measuring device;
A pressure gauge for measuring the pressure of the concentrated sludge discharged by the concentrated sludge supply pump;
A dewatering device for dewatering the concentrated sludge supplied by pressure from the concentrated sludge supply pump;
Based on the liquid level measured by the liquid level measuring device, the number of rotations of the concentrated sludge supply pump, and the press-fitting pressure to the dehydrator by the concentrated sludge measured by the pressure gauge, the concentration device, the concentrated sludge supply pump And a control device for controlling the dehydrating device. The control device includes a measured sludge liquid level that is the liquid level of the concentrated sludge that is measured by the liquid level measuring device, and a preset reference liquid level range that is a parameter that can be adjusted so that the concentrated sludge flows constantly. And when the value of the measured sludge liquid level is higher than the value of the reference liquid level range, it is determined in advance based on the treatment state and sludge properties of the liquid level measuring device and the concentrated sludge supply pump. When the value of the measured sludge liquid level is within the reference liquid level range, the value of the concentration apparatus control coefficient is maintained, and the value of the measured sludge liquid level is the reference liquid. If lower than the range value, decrease the value of the concentrator control coefficient,
The measurement pump rotation speed, which is the rotation speed of the concentrated sludge supply pump, and a pump reference rotation speed range, which is a preset reference rotation speed of the sludge concentration supply pump, which is a parameter that can be adjusted so that the concentrated sludge flows constantly. When the rotation speed value of the concentrated sludge feed pump is compared with the α reference rotation speed range, which is a value multiplied by the concentration apparatus control coefficient, the concentration apparatus has When the rotation speed of the concentrated screw shaft is increased and the value of the rotation speed of the concentrated sludge supply pump is within the α reference rotation speed range, the rotation speed of the concentrated screw shaft is maintained, and the rotation speed of the concentrated sludge supply pump 2. The control system according to claim 1, wherein when the value of is less than a value in the α reference rotation speed range, the rotation speed of the concentrating screw shaft is decreased. The control device includes a measured sludge liquid level that is the liquid level of the concentrated sludge that is measured by the liquid level measuring device, and a preset reference liquid level range that is a parameter that can be adjusted so that the concentrated sludge flows constantly. And when the value of the measured sludge liquid level is higher than the value of the reference liquid level range, it is determined in advance based on the treatment state and sludge properties of the liquid level measuring device and the concentrated sludge supply pump. When the value of the measured sludge liquid level is within the reference liquid level range, the value of the concentration apparatus control coefficient is maintained, and the value of the measured sludge liquid level is the reference liquid. If lower than the range value, decrease the value of the concentrator control coefficient,
Measurement pump rotation speed that is the rotation speed of the concentrated sludge supply pump, and pump reference rotation speed range that is a preset reference rotation speed of the concentrated sludge supply pump that is a parameter that can be adjusted so that the concentrated sludge flows constantly. Is compared with the α reference rotation speed range which is a value obtained by multiplying the concentration apparatus control coefficient, and when the rotation speed value of the concentrated sludge supply pump is larger than the value of the α reference rotation speed range, the concentration apparatus When the rotation speed of the outer cylinder screen is increased and the rotation speed value of the concentrated sludge supply pump is within the α reference rotation speed range, the rotation speed of the outer cylinder screen is maintained and the rotation of the concentrated sludge supply pump is performed. 2. The control system according to claim 1, wherein when the number value is smaller than the value of the α reference rotation speed range, the rotation speed of the outer cylinder screen is decreased. The control device further includes a preset reference press-fit pressure range that is a parameter that can be adjusted so that the press-fit pressure of the concentrated sludge measured by the pressure gauge and the press-fit pressure of the concentrated sludge are constant. When the value of the measured press-fit pressure is larger than the value of the reference press-fit pressure range, the rotational speed of the concentrated sludge supply pump is decreased, and when the measured press-fit pressure is within the reference press-fit pressure range, Maintaining the rotation speed of the concentrated sludge supply pump, if the value of the measured pressurization pressure is smaller than the value of the reference pressurization pressure range, increase the rotation speed of the concentrated sludge supply pump,
When the measurement pump rotation speed, which is the rotation speed of the concentrated sludge supply pump, is compared with the pump reference rotation speed range, and the value of the measurement pump rotation speed is greater than the pump reference rotation speed range, the dehydrator When the rotation speed of the dewatering screw shaft is decreased and the value of the measurement pump rotation speed is within the pump reference rotation speed range, the rotation speed of the dehydration screw shaft is maintained, and the value of the measurement pump rotation speed is 4. The control system according to claim 2, wherein the rotation speed of the dewatering screw shaft is increased when the value is smaller than a value in a pump reference rotation speed range. 5. The sludge stock solution is agglomerated and stirred by the polymer flocculant, the agglomerated sludge supplied at a constant flow rate is filtered, the concentrating device for generating concentrated sludge, and the concentrated sludge discharged by the concentrating device is temporarily stored. A liquid level measuring device for measuring the position of the stored concentrated sludge, a concentrated sludge supply pump for discharging the concentrated sludge temporarily stored by the liquid level measuring device, and a concentrated sludge discharged by the concentrated sludge supply pump A control device that controls a pressure gauge that measures the pressure of the dewatering device and a dewatering device that dehydrates the concentrated sludge that is press-fitted and supplied from the concentrated sludge supply pump,
Based on the liquid level measured by the liquid level measuring device, the number of rotations of the concentrated sludge supply pump, and the press-fitting pressure to the dehydrator by the concentrated sludge measured by the pressure gauge, the concentration device, the concentrated sludge supply pump And a control device for controlling the dehydrating device. Comparing a measured sludge liquid level that is the liquid level of the concentrated sludge measured by the liquid level measuring device with a preset reference liquid level range that is a parameter that can be adjusted so that the concentrated sludge flows constantly, If the value of the measured sludge liquid level is higher than the value of the reference liquid level range, a preset concentrator control coefficient that is determined based on the processing state and sludge properties of the liquid level measuring device and the concentrated sludge supply pump When the value of the measured sludge liquid level is within the reference liquid level range, the value of the concentrator control coefficient is maintained, and the value of the measured sludge liquid level is greater than the value of the reference liquid level range. If the value is too low, decrease the value of the concentrator control coefficient,
Measurement pump rotation speed that is the rotation speed of the concentrated sludge supply pump, and pump reference rotation speed range that is a preset reference rotation speed of the concentrated sludge supply pump that is a parameter that can be adjusted so that the concentrated sludge flows constantly. Is compared with the α reference rotation speed range which is a value obtained by multiplying the concentration apparatus control coefficient, and when the rotation speed value of the concentrated sludge supply pump is larger than the value of the α reference rotation speed range, the concentration apparatus When the value of the rotation speed of the concentrated sludge supply pump is within the range of the α reference rotation speed, the rotation speed of the concentration screw shaft is maintained and the rotation of the concentrated sludge supply pump is increased. The control device according to claim 5, wherein when the number value is smaller than the value of the α reference rotation speed range, the rotation speed of the concentrating screw shaft is decreased. Comparing a measured sludge liquid level that is the liquid level of the concentrated sludge measured by the liquid level measuring device with a preset reference liquid level range that is a parameter that can be adjusted so that the concentrated sludge flows constantly, If the value of the measured sludge liquid level is higher than the value of the reference liquid level range, a preset concentrator control coefficient that is determined based on the processing state and sludge properties of the liquid level measuring device and the concentrated sludge supply pump When the value of the measured sludge liquid level is within the reference liquid level range, the value of the concentrator control coefficient is maintained, and the value of the measured sludge liquid level is greater than the value of the reference liquid level range. If the value is too low, decrease the value of the concentrator control coefficient,
Measurement pump rotation speed that is the rotation speed of the concentrated sludge supply pump, and pump reference rotation speed range that is a preset reference rotation speed of the concentrated sludge supply pump that is a parameter that can be adjusted so that the concentrated sludge flows constantly. Is compared with the α reference rotation speed range which is a value obtained by multiplying the concentration apparatus control coefficient, and when the rotation speed value of the concentrated sludge supply pump is larger than the value of the α reference rotation speed range, the concentration apparatus When the rotation speed of the outer cylinder screen is increased and the rotation speed value of the concentrated sludge supply pump is within the α reference rotation speed range, the rotation speed of the outer cylinder screen is maintained and the rotation of the concentrated sludge supply pump is performed. The control device according to claim 5, wherein when the number value is smaller than the value of the α reference rotation speed range, the rotation speed of the outer cylinder screen is decreased. Furthermore, the measured press-fit pressure that is the press-fit pressure of the concentrated sludge measured by the pressure gauge is compared with a preset reference press-fit pressure range that is a parameter that can be adjusted so that the press-fit pressure of the concentrated sludge becomes constant, When the measured press-fit pressure value is larger than the reference press-fit pressure range value, the rotational speed of the concentrated sludge supply pump is decreased. When the measured press-fit pressure is within the reference press-fit pressure range, the concentrated sludge feed pump When the value of the measured press-fitting pressure is smaller than the value of the reference press-fitting pressure range, the rotational speed of the concentrated sludge supply pump is increased,
When the measurement pump rotation speed, which is the rotation speed of the concentrated sludge supply pump, is compared with the pump reference rotation speed range, and the value of the measurement pump rotation speed is greater than the pump reference rotation speed range, the dehydrator When the rotation speed of the dewatering screw shaft is decreased and the value of the measurement pump rotation speed is within the pump reference rotation speed range, the rotation speed of the dehydration screw shaft is maintained, and the value of the measurement pump rotation speed is The control device according to claim 6 or 7, wherein when the pump rotational speed is smaller than a value in a pump reference rotational speed range, the rotational speed of the dehydrating screw shaft is increased. A step of concentrating a sludge stock solution to be agglomerated and stirred by a polymer flocculant, filtering the agglomerated sludge supplied at a constant flow rate, and generating a concentrated sludge;
The liquid level measuring device temporarily stores the concentrated sludge discharged by the concentrator, and measures the position of the stored concentrated sludge;
A step in which the concentrated sludge supply pump discharges the concentrated sludge temporarily stored by the liquid level measuring device;
A pressure gauge measuring the pressure of the concentrated sludge discharged by the concentrated sludge supply pump;
A step of dehydrating the concentrated sludge supplied by pressure from the concentrated sludge supply pump;
Based on the liquid level measured by the liquid level measuring device, the number of rotations of the concentrated sludge supply pump, and the pressure applied to the dehydrator by the concentrated sludge measured by the pressure gauge, the control device, And a step of controlling the dewatering apparatus.

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