JP5041299B2 - Operation control method of screw press connected to rotary concentrator - Google Patents

Description

  The present invention relates to an operation control method for a screw press, and more particularly to an operation control method for a screw press that interlocks and controls a pre-concentration device in order to control the press-fitting pressure of concentrated sludge supplied to the screw press to be constant.

Conventionally, organic sludge such as sewage, human waste, or food production processing wastewater has been added with a polymer flocculant and stirred and mixed in a coagulation tank to generate coagulated flocs. If organic sludge with a low concentration is directly concentrated and dewatered with a screw press, the sludge concentration is low on the sludge injection side of the screw press, so the outer cylinder screen in the concentration zone has a larger water load than the solid load, and the outer cylinder screen. A large amount of water is discharged from the water. Therefore, in order to reduce the water load due to the screw press, a method of further concentrating the agglomerated floc with a concentrating device and performing filtration dehydration is employed. In these concentrators, for example, 1% of sludge is concentrated to 4 to 5%, and this concentrated sludge is filtered and dehydrated with a screw press.
As the concentrator, a rotary concentrator for concentrating while rotating a screw shaft provided in an outer cylinder screen and regenerating a filtration surface that is likely to be clogged is disclosed in Japanese Patent Application Laid-Open No. 2004-133830. A person has proposed.
In addition, as a dehydrating device, a screw press that includes a cylindrical screen and a screw shaft that is rotatable inside thereof, and that separates solid and liquid while conveying aggregated sludge by driving rotation of the screw shaft. The concentrated sludge supply pump and the pressure detector for detecting the press-fitting pressure of the concentrated sludge supplied to the screw press are provided, and the concentrated sludge is supplied so that the press-fitting pressure detected by the pressure detector is substantially constant. The method of controlling the supply flow rate of the pump is also proposed by the applicant of the present invention as described in, for example, Patent Document 2.
In addition, as a method of controlling the concentration sludge concentration of the differential speed rotary concentrator that concentrates sludge while rotating the outer cylinder screen and the screw shaft at a differential speed, a power detector is provided in the sludge receiving tank of the concentrated sludge, and the power detector A technique for discriminating the electric signal of the concentrated sludge concentration detected by the control and controlling the chemical injection rate, the screw shaft rotation speed, and the outer cylinder screen rotation speed is also disclosed in the application of the present invention as described in Patent Document 3, for example. A person has proposed.
In addition, a coagulation mixing tank with a concentration function and a standard coagulation mixing tank are arranged in series, and a constant flow rate of raw sludge is supplied to the coagulation mixing tank with a concentration function, and the pressure of the coagulation sludge pressed into the screw press is constant. The sludge concentration of the concentrated sludge is adjusted by changing the chemical injection 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. For example, as described in Patent Document 4, the applicant of the present invention has also proposed a technique for adjusting the solids throughput with a constant press-fitting pressure in the coagulation mixing tank before being supplied to the coagulation mixer.

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 concentrator is once put in a storage tank, and then condensed again as a stock solution for dehydration. In this case, the sludge is retained in the concentrated sludge storage tank for a long time due to the treatment procedure and time constraints, and as a result, the decay of the concentrated sludge proceeds and the dewaterability is lowered. 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. Further, in order to dehydrate after concentration, not only the above-described concentration device and dewatering device, but also a concentrated sludge storage tank is required, and a large installation area is required.
Conventional screw presses can control sludge with good filterability by controlling the number of rotations of the screw to prevent overload and obtain a cake with a uniform moisture content. On the other hand, if the volume of the filtration chamber is reduced and the pressure is dewatered, the filtration surface of the outer cylinder screen is clogged early. 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 a conventional screw press operation control method, 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 screw press in order to control the press-fitting pressure of the stock solution supplied to the screw press to a constant level. To do. In practice, however, 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 that controls the chemical injection rate, screw shaft rotation speed, outer cylinder screen rotation speed and keeps the concentrated sludge concentration constant, the sludge concentration after concentration is stable, and the processing after concentration Process management is facilitated. However, fluctuations in the sludge properties cause variations in the amount of concentrated sludge, making it difficult to ensure the continuity of the processing amount with the subsequent continuous dehydrator. When temporarily storing concentrated sludge, a concentrated sludge storage tank was required, and a large installation area was required.
In addition, the control method of the dehydrator, which is equipped with a coagulation mixing tank with a concentration function in front of a standard coagulation mixing tank, can be used for coagulation mixing with a concentration function for fluctuations in raw sludge concentration and solid sludge treatment amount. 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 dewaterability, the load on the subsequent 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.

This invention controls the press-fitting pressure of concentrated sludge supplied to a screw press to a constant level, and also makes the flow rate of the stock solution supplied to the rotary concentrator in the previous stage constant, so that the screw shaft of the rotary concentrator, the concentrated sludge supply pump, An operation control method for controlling the rotational speed of a screw shaft of a screw press is provided.

Concentrated sludge pipe arranged in the discharge part of the rotary concentrator with screw shaft inside is connected to the concentrated sludge supply pump, and a screw press is continuously connected to the discharge side of the concentrated sludge supply pump, so that rotary concentration In the sludge dewatering system that presses the concentrated sludge of the machine into the screw press and dehydrates it, the reference pressure of the concentrated sludge to be pressed into the screw press, the reference rotation speed of the concentrated sludge supply pump, and the reference rotation of the screw shaft of the rotary concentrator The number of rotations, the number of rotations of the concentrated sludge supply pump, the number of rotations of the screw shaft of the rotary concentrator, and the number of rotations of the screw shaft of the screw press . set the decrease amount, when measuring the injection pressure of the concentrated sludge, injection pressure of the concentrated sludge was the measurement is out of range of the reference preset pressure, the concentrated sludge When the reference rotation speed of the feed pump and the reference rotation speed of the screw shaft of the rotary concentrator are increased or decreased step by step, and the rotation speed of the concentrated sludge supply pump falls outside the preset reference rotation speed range, the screw press The standard rotation speed of the screw shaft is increased and decreased step by step to control the press-fitting pressure of the concentrated sludge within the range of the reference pressure, improving the performance of the screw press and enabling stable operation. . In addition, by directly connecting the rotary concentrator and the screw press with a press-fitting pump, the period from concentration to dehydration can be shortened, and there is no concern about rot and can contribute to dehydration efficiency.

Specifically, the pressure of the concentrated sludge that is pressed into the screw press is measured at regular intervals, and when the measured pressure of the concentrated sludge is lower than the preset reference pressure, the rotation speed of the concentrated sludge supply pump and the rotary concentrator The screw shaft rotation speed is increased by the set rotation speed range, and this operation is repeated until the pressurization pressure of the concentrated sludge rises within the standard pressure range, and the rotation speed of the concentrated sludge supply pump is set to the preset maximum standard. If the rotational speed exceeds the rotational speed, the rotational speed of the screw shaft of the screw press is decreased by the set rotational speed range, and this operation is repeated until the press-fitting pressure of the concentrated sludge rises within the standard pressure range. When the press-fit pressure is higher than the preset reference pressure, the rotation speed of the concentrated sludge supply pump and the rotation speed of the screw shaft of the rotary concentrator were set. When the rotation speed of the concentrated sludge feed pump becomes smaller than the preset minimum reference rotation speed, the screw press screw is turned on. This operation is repeated until the rotational speed of the shaft is increased by the set rotational speed range and the press-fitting pressure of the concentrated sludge falls within the range of the reference pressure.

In the system for controlling the pressure of the concentrated sludge within the range of the reference pressure, the reference rotation of the polymer supply pump that supplies the polymer flocculant to the stock solution supply pipe of the stock solution supply pump that supplies the stock solution sludge to the rotary concentrator The number of rotations of the polymer feed pump and the rotation speed range that increases or decreases the rotation speed of the polymer supply pump are set. When the rotational speed of the screw shaft of the rotary concentrator is decreased stepwise, the rotational speed of the polymer supply pump is increased stepwise by the set rotational speed range. Thus, the concentration of the discharged sludge of the rotary concentrator can be adjusted.

Also, the rotation speed of the concentrated sludge supply pump is the maximum rotation speed, the rotation speed of the screw shaft of the rotary concentrator is the maximum rotation speed, the rotation speed of the polymer supply pump is the minimum rotation speed, or the rotation of the screw shaft of the screw press. If the pressure of the concentrated sludge that is press-fitted into the screw press does not return to the standard pressure range even if the number reaches the minimum rotation speed, an alarm is issued or the operation is stopped, and the concentrated sludge supply pump Either the minimum number of rotations, the minimum number of rotations of the screw shaft of the rotary concentrator, the maximum number of rotations of the polymer feed pump, or the maximum number of rotations of the screw shaft of the screw press If the pressure of the concentrated sludge that is press-fitted into the screw press does not return to the standard pressure range even if the pressure is reached, an alarm is issued or the operation is stopped. Because, and serves as a safety conscious processing system.

Concentrated sludge pipes are installed at the discharge part of the rotary concentrator, and while performing press-fitting pressure comparison control, the reference liquid level of the concentrated sludge stored in the concentrated sludge pipe, the reference rotation speed of the raw liquid supply pump that supplies the raw sludge, And the rotational speed to increase or decrease the rotational speed of the stock solution supply pump step by step, measure the liquid level in the concentrated sludge tube, and when the liquid level is outside the preset reference liquid level range, Controls the liquid level of the concentrated sludge tube within the standard liquid level range by increasing or decreasing the rotational speed step by step, ensuring continuity of sludge treatment between the rotary concentrator and the screw press. Is.

Specifically, the liquid level of the concentrated sludge stored in the concentrated sludge pipe was measured at regular intervals, and when the measured liquid level of the concentrated sludge pipe was lower than the preset reference liquid level, the number of revolutions of the stock solution supply pump was set. Repeat this operation until the liquid level of the concentrated sludge rises within the range of the reference liquid level by increasing the rotation speed range, and when the measured liquid level of the concentrated sludge pipe is higher than the preset reference liquid level, This operation is repeated until the rotation speed of the supply pump is reduced by the set rotation speed width and the liquid level of the concentrated sludge falls within the range of the reference liquid level.

In addition, if the concentrated sludge liquid level stored in the concentrated sludge pipe does not return to the standard liquid level range even if the rotation speed of the stock solution supply pump reaches the maximum rotation speed or the minimum rotation speed, an alarm is issued. The operation will be stopped, and the processing system will be safe.

Concentrated sludge supply pump, rotary concentrator screw shaft rotation speed, screw press to keep the pressure of the concentrated sludge supplied to the screw press constant, and to keep the flow rate of the concentrate supplied to the rotary concentrator in the previous stage constant Since the three parameters of the screw shaft rotation speed are varied step by step, the performance of the screw press is improved and stable operation is possible. In addition, by directly connecting the rotary concentrator and the screw press with a press-fitting pump, the period from concentration to dehydration can be shortened, and there is no concern about rot and can contribute to dehydration efficiency. Furthermore, the entire apparatus becomes compact and space-saving.

It is an operation control system of a concentrator and a dehydrator according to the present invention. Similarly, it is a partial longitudinal cross-sectional view of a rotary concentrator. Similarly, it is a partial longitudinal cross-sectional view of a screw press. Similarly, it is an enlarged view of the supply side of the screw press. Similarly, it is an enlarged view of the discharge side of the screw press. Similarly, it is a flowchart of an operation control method.

FIG. 1 shows an operation control system for a concentrator and a dehydrator according to this embodiment. A processing stock solution such as sludge stored in a sludge storage tank (not shown) is supplied to a stock solution flow rate ( (Also referred to as “supply flow rate”) is supplied to the aggregating apparatus 3 through the stock solution supply pipe 2.
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. The flocculant supply pipe 5 may be 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 controlled by the controller 60 in proportion to the rotation speed of the stock solution supply pump 1.
The agglomeration device 3 is a device in which sludge and polymer flocculant supplied from the stock solution supply pump 1 and the polymer supply pump 4 to the agglomeration device 3 are agitated and mixed by a stirrer to generate agglomeration floc. In this configuration, the stock solution and the polymer flocculant that have 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 apparatus 3 is supplied to the concentrator 10 through the agglomerated sludge supply pipe 9.

The concentrator 10 of the present embodiment uses a rotary concentrator 11 , and FIG. 2 is a longitudinal side view of the rotary concentrator. 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 through the outer cylinder drive shaft 17. A sludge supply path 21 is provided at the front end portion of the screw shaft 14, a plurality of supply ports 21 a are opened at the start end portion 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.

  As shown in FIG. 2, an outer cylinder driving shaft 23 of the outer cylinder screen 12 and a screw driving shaft 20 of the screw shaft 14 are individually linked to an outer cylinder driving machine 23 and a screw driving machine 24. And the screw shaft 14 is rotated in the reverse direction by a differential speed. The sludge supplied to the filtration chamber 22 from the supply path 21 of the screw shaft 14 is separated from the filtrate from the outer cylinder screen 12 while rotating the outer cylinder screen 12 and the screw shaft 14 in the reverse direction, and the concentrated sludge is removed from the outlet flange 16. From the outlet 16a. 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 filtration surface of the outer cylinder screen 12 as a clogging thread is regenerated to facilitate the discharge of the filtrate, and enables mass treatment of sludge having a low concentration. Reference numeral 25 denotes a washing water pipe disposed along the outer cylinder screen 12 and jets high-pressure water onto the screen surface of 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, the bridge of the concentrated sludge in the concentrated sludge pipe 26 is prevented, and the concentrated sludge supply pump 27 is smoothly supplied. It becomes possible to supply.

  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 to some extent, and is provided with a liquid level meter 28 for measuring the storage amount. 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.

  The dehydrator 30 of the present embodiment uses a screw press 31 capable of continuously dewatering concentrated sludge. The concentrated sludge supply in which the rotary concentrator 11 is mounted on the screw press 31 and the discharge side is connected to the screw press 31 is used. The pump 27 is disposed in the concentrated sludge pipe 26 erected at the discharge part of the rotary concentrator 11. Since the concentrator is mounted on the dehydrator, it is not necessary to retain the concentrated sludge in the storage tank for a long time, and the dewatering efficiency 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 a wastewater treatment facility such as sewage, human waste, village drainage, or a factory, it becomes a space-saving concentration dehydration facility.

FIG. 3 is a partial longitudinal side view of a screw press used in a constant press-fitting pressure control device. 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. Is installed. The screw shaft 34 is enlarged 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 is reduced from the supply side to the discharge side.
FIG. 4 is an enlarged view of the supply side of the screw press, and a sprocket 37 is fitted on the inlet flange 36 fitted on the supply side of the outer cylinder screen 32, and the outer cylinder drive that can be rotated forward and backward is mounted on the frame 38. It is linked to the machine 39. The screw shaft 34 is provided with a supply path 41 of 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. 33 so as not to be affected.
FIG. 5 is an enlarged view of the discharge side of the screw press, in which a rotating plate 42 connected to the discharge side of the outer cylinder screen 32 is supported on a frame 43, and a screw shaft 34 provided in the outer cylinder screen 32 is screwed onto the screw shaft 34. A drive shaft 44 is connected. 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 linked to a screw drive 51 mounted on the frame 43.
As shown in FIG. 3, the screw driver 51 of the screw shaft 34 is operated, the concentrated sludge is supplied from the supply path 41 of the screw shaft 34 to the filtration chamber 35, and the concentrated sludge is transferred by the screw blades 33, and the outer cylinder screen Separate the filtrate from 32. 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 drive 39. To clean the entire surface of the outer cylinder screen 32. A filtrate trough 53 is disposed below the outer cylinder screen 32, and reference numeral 54 is a cake receiving tank for dehydrated cake disposed at the terminal end of the screw press 31.

In the operation control method according to the present invention, in the system for supplying the stock solution to the rotary concentrator 11 in a fixed amount, in order to operate the screw press 31 stably, the press-fitting pressure such as sludge supplied to the screw press 31 is controlled to be constant. It is based on doing.
Therefore, in order to control the press-fitting pressure to be constant, the concentrated sludge supply pump 27 is rotationally controlled to control the supply flow rate of the concentrated sludge supplied to the screw press 31.

In more detail, when the operation of the screw press 31 is started, the press-fitting pressure P 1 of concentrated sludge supplied to the screw press 31 is sent to the control unit 60 is detected by the pressure gauge PS.
During operation of the screw press 31, if the sludge filterability deteriorates due to fluctuations in sludge properties and the load on the screw press 31 increases, the press-fitting pressure P1 of the concentrated sludge increases. On the other hand, when the filterability of sludge is recovered and the load on the screw press 31 is reduced, the pressure P1 of the concentrated sludge is reduced.
Therefore, in the control device 60, when the press-fit pressure P1 of the pressure gauge PS is compared with the preset reference pressure P0 and is higher than the reference pressure P0, the concentrated sludge supply is performed to reduce the rotation speed of the concentrated sludge supply pump 27. A command is given to the pump 27 to reduce the supply flow rate. On the other hand, when the press-fitting pressure P1 is lower than the reference pressure P0, a command is given to the concentrated sludge supply pump 27 to increase the rotation speed of the concentrated sludge supply pump 27 and the supply flow rate is increased.
Therefore, by adjusting the supply flow rate by controlling the rotation speed of the concentrated sludge supply pump 27, the press-fitting pressure P1 of the concentrated sludge supplied to the screw press 31 is maintained substantially at the reference pressure P0.
The reference pressure P0 can be set with a certain range, and when the press-fit pressure P1 is within the set range, the normal operation is continued while maintaining the current state.

However, the amount of treatment varies due to fluctuations in dewaterability. For example, when the press-fitting pressure supplied to the screw press 31 is reduced, the rotation rate of the concentrated sludge supply pump 27 is increased to increase the supply amount. The concentrated sludge supplied to the supply pump 27 is insufficient, and the continuity between the rotary concentrator 11 and the screw press 31 may be interrupted. Moreover, the processing amount in the rotary concentrator 11 fluctuates due to the concentration fluctuation of the stock solution. For example, when the stock solution concentration decreases, the amount of concentrated sludge in the rotary concentrator 11 decreases and the concentrated sludge supplied to the concentrated sludge supply pump 27 is insufficient. Will do.
Therefore, the rotational speed of the screw shaft 14 of the rotary concentrator 11 is simultaneously controlled so as to adjust the processing amount of the rotary concentrator 11 in the previous stage in accordance with the rotation control of the concentrated sludge supply pump 27.

More specifically, when the press-fitting pressure P1 is higher than the reference pressure P0, the controller 60 gives a command to reduce the rotational speed of the concentrated sludge supply pump 27 and rotates to reduce the concentrated sludge amount from the rotary concentrator 11. A command is given to the screw drive 24 of the concentrator 11 to reduce the rotational speed of the screw shaft 14. On the other hand, when the press-fit pressure P1 is lower than the reference pressure P0, the control device 60 gives a command to increase the rotation speed of the concentrated sludge supply pump 27 and also increases the amount of concentrated sludge discharged from the rotary concentrator 11. 11 is given to the screw driver 24 to increase the rotational speed of the screw shaft 14.
Further, the rotational speed of the screw shaft 14 of the rotary concentrator 11 is decreased, the rotational speed of the polymer supply pump 4 is increased, or the rotational speed of the screw shaft 14 of the rotary concentrator 11 is increased. An operation of adjusting the discharge concentration of the rotary concentrator 11 by reducing the rotation speed of the supply pump 4 may be performed.

Next, the controller 60 compares the increased or decreased rotational speed N2 of the concentrated sludge supply pump 27 with the preset standard rotational speed N02 of the concentrated sludge supply pump 27, and the rotational speed of the concentrated sludge supply pump 27 is determined. When N2 is higher than the reference rotational speed N02 , a command is given to the screw driver 51 of the screw press 31 to increase the pressure in the filtration chamber of the screw press 31, and the rotational speed of the screw shaft 34 is decreased. On the other hand, when the rotation speed N2 is lower than the reference rotation speed N02 , a command is given to the screw driver 51 of the screw press 31 to increase the rotation speed of the screw shaft 34 in order to lower the pressure in the filtration chamber of the screw press 31.
The reference rotation speed N02 can be set with a certain range, and when the rotation speed N2 of the concentrated sludge supply pump 27 is within the set width, normal operation is continued while maintaining the current state.

Once the rotational speed of the concentrated sludge supply pump 27, the rotational speed of the screw shaft 14 of the rotary concentrator 11, and the rotational speed of the screw shaft 34 of the screw press 31 are changed, the press-fitting pressure P1 is measured again after a certain period of time, The above operation is repeated until the press-fit pressure P1 returns to the reference pressure P0.

The rotational speed of the concentrated sludge supply pump 27, the rotational speed of the screw shaft 14 of the rotary concentrator 11, and the rotational speed of the screw shaft 34 of the screw press 31 are increased or decreased in stages until the press-fit pressure P1 returns to the reference pressure P0. . The change width of each rotation speed is set in advance. An upper limit and a lower limit for each rotation speed may be set, and an alarm may be issued when the upper limit or the lower limit is reached, or the operation may be automatically stopped for investigation.

Separately from the above-described constant solution flow rate control, in order to control the amount of concentrated sludge in the concentrated sludge pipe 26 to be constant, the raw solution supply for supplying the raw solution to the rotary concentrator 11 in order to control the stock solution supply amount of the rotary concentrator 11 The rotation control of the pump 1 is performed.

More specifically, in the control device 60, the liquid level L1 of the liquid level meter 28 disposed in the concentrated sludge pipe 26 is compared with the preset reference liquid level L0, so that the liquid level L1 is the reference liquid level L0. If higher, a command is given to the stock solution supply pump 1 that supplies the stock solution to the rotary concentrator 11 to reduce the amount of concentrated sludge in the concentrated sludge tube 26, and the rotational speed is reduced. On the other hand, when the liquid level L1 is lower than the reference liquid level L0, a command is given to the stock solution supply pump 1 that supplies the stock solution to the rotary concentrator 11 in order to increase the amount of concentrated sludge in the concentrated sludge tube 26, and the rotational speed is set. increase.

Once the number of revolutions of the stock solution supply pump 1 that supplies the stock solution to the rotary concentrator 11 is changed, the liquid level L1 is measured again after a predetermined time has elapsed until the liquid level L1 returns to the reference liquid level L0. Repeat the above operation.

The reference liquid level L0 can be set with a certain width, and when the liquid level L1 is within the set width, the normal operation is continued while maintaining the current state.
The number of revolutions of the stock solution supply pump 1 that supplies the stock solution to the rotary concentrator 11 is increased or decreased in stages until the liquid level L1 returns to the reference liquid level L0. The range for changing the rotational speed is set in advance. An upper limit and a lower limit of the number of revolutions may be set, and an alarm may be issued when the upper limit or the lower limit is reached, or the operation may be automatically stopped for investigation.

FIG. 6 is a flowchart of the operation control method of the rotary concentrator and the screw press according to this embodiment.
A. Initial setting A reference pressure P0 when pressing the concentrated sludge into the screw press 31 is set. In this embodiment, the reference pressure P0 is set between the maximum reference pressure P0max and the minimum reference pressure P0min.
The reference rotation speed N1, the maximum rotation speed N1max, and the minimum rotation speed N1min of the stock solution supply pump 1 are set, and the rotation speed n1 that is increased or decreased in stages is set.
Reference rotational speed N02 of the concentrated sludge supply pump 27, the maximum rotational speed N2max, sets the minimum rotation speed N2min, setting the rotational speed n 2 of stepwise increased or decreased. In this embodiment, the reference rotation speed N02 is set between the maximum reference rotation speed N02max and the minimum reference rotation speed N02min.
Reference rotational speed N3 of the screw shaft 14 of the rotary concentrator 11, the maximum rotational speed N3max, sets the minimum rotation speed N3min, setting the rotational speed n 3 for stepwise increasing or decreasing.
Reference rotational speed N4 of the screw shaft 34 of the screw press 31, the maximum rotational speed N4max, sets the minimum rotation speed N4min, setting the rotational speed n 4 of stepwise increased or decreased.
Reference rotational speed N5 of the polymer feed pump 4, the maximum rotational speed N5max, sets the minimum rotation speed N5min, setting the rotational speed n 5 of stepwise increased or decreased.
A reference liquid level L0 for storing the concentrated sludge in the concentrated sludge pipe 26 is set. In this embodiment, the reference liquid level L0 is set between the maximum reference liquid level L0max and the minimum reference liquid level L0min.

B. Start of operation Operate each device at the above standard speed and rated speed. The polymer supply pump 4 is operated by proportional control according to the rotational speed of the stock solution supply pump 1. Further, the outer cylinder driver 23 that drives the outer cylinder screen 12 of the rotary concentrator 11 rotates at a differential speed by proportional control in accordance with the rotational speed of the screw driver 24 that drives the screw shaft 14.

C. Intrusion pressure comparison The intrusion pressure P1 when the concentrated sludge is intruded into the screw press 31 is measured and compared with the reference pressure P0.
When the press-fit pressure P1 is within the reference pressure P0, the operation of each device is continued in the current state.
When the press-fitting pressure P1 is smaller than the reference pressure P0 (P1 <P0 min), the process proceeds to D in the flowchart, and control is performed to increase the rotational speed of the concentrated sludge supply pump 27 stepwise.
When the press-fit pressure P1 is larger than the reference pressure P0 (P0max <P1), the process proceeds to G in the flowchart, and control is performed to decrease the rotational speed of the concentrated sludge supply pump 27 stepwise.

D. Concentrated sludge supply pump rotation speed increase In the above flow chart C, when the press-fit pressure P1 is smaller than the reference pressure P0 (P1 <P0 min), the rotation speed of the concentrated sludge supply pump 27 is increased by a preset rotation speed (N2 + n2). I do.

E. Increasing the number of revolutions of the screw shaft of the concentrator In the flowchart D above, after increasing the number of revolutions of the concentrated sludge supply pump 27, the number of revolutions of the screw shaft 14 of the rotary concentrator 11 is increased by a preset number of revolutions (N3 + n3). I do.

F. Decreasing the number of rotations of the polymer supply pump In the flowchart E, after increasing the number of rotations of the screw shaft 14 of the rotary concentrator 11, the number of rotations of the polymer supply pump 4 is decreased by a preset number of rotations (N5-n5). Take control.

G. Concentration sludge supply pump rotational speed reduction In the flowchart C, when the press-fit pressure P1 is larger than the reference pressure P0 (P0max <P1), the rotational speed of the concentrated sludge supply pump 27 is decreased by a preset rotational speed (N2-n2). ) Control.

H. Decrease in the number of revolutions of the screw shaft of the concentrator In the above-mentioned flowchart G , after the number of revolutions of the concentrated sludge supply pump 27 is reduced, the number of revolutions of the screw shaft 14 of the rotary concentrator 11 is reduced by a preset number (N3-n3). ) Control.

I. Increasing the number of rotations of the polymer supply pump In the above flowchart H, after the number of rotations of the screw shaft 14 of the rotary concentrator 11 is decreased, the number of rotations of the polymer supply pump 4 is increased by a preset number (N5 + n5). Do.

J. et al. Concentrated sludge supply pump rotation speed comparison The rotation speed N2 of the concentrated sludge supply pump 27 is measured and compared with the reference rotation speed N02.
When the rotation speed N2 is within the reference rotation speed N02, the process returns to the flowchart C, and the press-fit pressure P1 is measured and compared with the reference pressure P0.
When the rotational speed N2 is larger than the reference rotational speed N02 (N02max <N2), the process proceeds to K in the flowchart, and control is performed to decrease the rotational speed of the screw shaft 34 of the screw press 31 in a stepwise manner.
When the rotation speed N2 is smaller than the reference rotation speed N02 (N2 <N02min), the control proceeds to L in the flowchart and the rotation speed of the screw shaft 34 of the screw press 31 is increased stepwise.

K. Decreasing the screw shaft rotation speed of the dehydrator In the flowchart J above, when the rotation speed N2 of the concentrated sludge supply pump 27 is larger than the reference rotation speed N02 (N02max <N2), the rotation speed of the screw shaft 34 of the screw press 31 is set in advance. Control to decrease by the set number of revolutions (N4-n4) is performed.

L. Increase of the screw shaft rotation speed of the dehydrator In the above flowchart J, when the rotation speed N2 of the concentrated sludge supply pump 27 is smaller than the reference rotation speed N02 (N2 <N02min), the rotation speed of the screw shaft 34 of the screw press 31 is set in advance. Control (N4 + n4) for increasing the set number of revolutions is performed.

After a predetermined time has elapsed, the press-fit pressure P1 is measured again, and the above operation is repeated until the press-fit pressure P1 returns to the reference pressure P0. The rotation speed of the concentrated sludge supply pump 27 is the maximum rotation speed N2max or the minimum rotation speed N2min, and the rotation speed of the screw shaft 14 of the rotary concentrator 11 is the maximum rotation speed N3max or the minimum rotation speed N3min. Even if the rotational speed of the pump 4 reaches the maximum rotational speed N5max or the minimum rotational speed N5min, and the rotational speed of the screw shaft 34 of the screw press 31 reaches the maximum rotational speed N4max or the minimum rotational speed N4min, the press-fit pressure P1 remains the reference pressure. If it does not return to P0, an alarm is issued or the operation is automatically stopped.

M.M. Liquid level comparison The liquid level L1 at the time of storing concentrated sludge in the concentrated sludge pipe 26 is measured and compared with the reference liquid level L0.
When the liquid level L1 is within the reference liquid level L0, the operation of each device is continued in the current state.
When the liquid level L1 is smaller than the reference liquid level L0 (L1 <L0min), the process proceeds to N in the flowchart, and control is performed to increase the rotational speed of the stock solution supply pump 1 stepwise.
When the liquid level L1 is larger than the reference liquid level L0 (L0max <L1), the process proceeds to O in the flowchart, and control is performed to decrease the rotational speed of the stock solution supply pump 1 stepwise.

N. Increase in the number of revolutions of the stock solution supply pump In the flowchart M, when the liquid level L1 is smaller than the reference level L0 (L1 <L0min), the control unit increases the number of revolutions of the stock solution supply pump 1 by a preset number of revolutions (N1 + n1). I do.

O. Decrease in the number of revolutions of the stock solution supply pump In the flowchart M, when the liquid level L1 is larger than the reference level L0 (L0max <L1), the number of revolutions of the stock solution supply pump 1 is decreased by a preset number of revolutions (N1-n1). ) Control.

The liquid level L1 is measured again after a certain period of time, and the above operation is repeated until the liquid level L1 returns to the reference liquid level L0. If the liquid level L1 does not return to the reference liquid level L0 even if the rotation speed of the stock solution supply pump 1 reaches the maximum rotation speed N1max or the minimum rotation speed N1min, an alarm is issued or the operation is automatically stopped.

As a concentrator, a rotary concentrator is smaller and more compact and has a smaller motor capacity and power saving than conventional concentrators such as a belt-type concentrator and a multi-disc concentrator. Further, the rotary concentrator can easily adjust the concentrated concentration by controlling the rotational speed of the screw shaft.
As a dehydrator, a screw press type dehydrator is smaller and more compact and has a smaller motor capacity and power saving than conventional continuous dehydrators such as a belt-type dehydrator and a centrifugal dehydrator. In addition, the screw press is easy to operate stably by constant press-fitting pressure control.
By combining this rotary concentrator and a screw press, it is possible to collectively control from concentration to dehydration, and contribute to the industry with space and energy savings.

1 Stock solution supply pump 4 Polymer supply pump
10 Concentrator 11 Rotary Concentrator 14 Screw Shaft 26 Concentrated Sludge Pipe 27 Concentrated Sludge Supply Pump
30 Dehydrator 31 Screw press 34 Screw shaft

Claims (7)

The concentrated sludge pipe (26) disposed in the discharge part of the rotary concentrator (11) in which the screw shaft (14) is disposed is connected to the concentrated sludge supply pump (27), and the concentrated sludge supply pump (27 The screw press (31) is connected to the discharge side of the concentrator), and the concentrated sludge of the concentrator (10 ) is press-fitted into the screw press (31) , and in the sludge dewatering system for dehydration treatment, the screw press (31) is press-fitted. Reference pressure (P0) of the concentrated sludge, reference rotation speed (N02) of the concentrated sludge supply pump (27), reference rotation speed (N3) of the screw shaft (14) of the rotary concentrator (11), and screw press ( 31) set the reference rotational speed (N4) of the screw shaft (34),
Stepwise, from only the rotational speed (n2) standard rotation speed of the enrichment sludge supply pump (27) (N02), the rotational speed from a reference rotational speed of the screw shaft of the rotary concentrator (11) (14) (N3 ) ( n3) only, set the value to increase or decrease by the rotation speed (n4) from the screw axis of the screw press (31) (34 standard rotation speed of the) (N4), by measuring the injection pressure of the concentrated sludge (P1), this When the measured pressure (P1) of the concentrated sludge falls outside the preset reference pressure (P0), the reference rotation speed (N02) of the concentrated sludge supply pump (27) and the rotary concentrator (11) When the reference rotational speed (N3) of the screw shaft (14) is increased or decreased stepwise, and the rotational speed (N2) of the concentrated sludge supply pump (27) is outside the preset reference rotational speed (N02). , Screw press (31) And Liu axis reference rotation speed (34) and (N4) stepwise increased or decreased, with the rotary concentrator, characterized by controlling injection pressure of the concentrated sludge to (P1) in the range of the reference pressure (P0) Operation control method of the screw press to be installed. When the pressurization pressure (P1) of the concentrated sludge that is press-fitted into the screw press (31) is measured at regular intervals, and the measured pressurization pressure (P1) of the concentrated sludge is lower than a preset reference pressure (P0), the concentrated sludge Increase the reference rotation speed (N02) of the supply pump (27) and the reference rotation speed (N3) of the screw shaft (14) of the rotary concentrator (11) by the rotation speed (n2, n3), respectively, and press the concentrated sludge. This operation is repeated until the pressure (P1) rises within the range of the reference pressure (P0), and when the rotation speed (N2) of the concentrated sludge supply pump (27) becomes larger than the preset maximum reference rotation speed (N02max), The reference rotation speed (N4) of the screw shaft (34) of the screw press (31) is decreased by the rotation speed (n4), and the pressurization pressure (P1) of the concentrated sludge rises within the range of the reference pressure (P0). This operation is repeated until the measured pressure (P1) of the concentrated sludge is higher than the preset reference pressure (P0), and the reference rotation speed (N02) of the concentrated sludge supply pump (27) and the rotary concentrator ( 11) Decrease the reference rotational speed (N3) of the screw shaft (14) by the rotational speeds (n2, n3), respectively, until the press-fitting pressure (P1) of the concentrated sludge falls within the range of the reference pressure (P0). When the operation is repeated and the rotation speed (N2) of the concentrated sludge supply pump (27) becomes smaller than the preset minimum reference rotation speed (N02min), the reference rotation speed (N4) of the screw shaft (34) of the screw press (31). the is increased by the rotational speed (n4), the rotation of the claim 1, characterized in that repeating this operation until the injection pressure of the concentrated sludge (P1) falls within the range of the reference pressure (P0) Screw press operation control method for continuously arranged in compressor. In the system for controlling the pressure (P1) of the concentrated sludge within the range of the reference pressure (P0), to the raw liquid supply pipe (2) of the raw liquid supply pump (1) for supplying the raw liquid sludge to the rotary concentrator (11). , the reference rotational speed of the polymer feed pump for supplying the polymer flocculant (4) (N5), and a reference rotational speed (N5) stepwise polymer feed pump (4), rotation number (n5) only When the value to be increased or decreased is set and the reference rotational speed (N3) of the screw shaft (14) of the rotary concentrator (11) is increased stepwise, the reference rotational speed (N5) of the polymer supply pump (4) is simultaneously increased. When the rotational speed (n5) is decreased stepwise and the reference rotational speed (N3) of the screw shaft (14) of the rotary concentrator (11) is decreased stepwise, at the same time, the reference of the polymer feed pump (4) Step the number of revolutions (N5) by the number of revolutions (n5) Screw press operation controller method of continuously arranged to the rotation concentrator according to claim 1 or 2, characterized in that to pressure. The rotation speed of the concentrated sludge supply pump (27) is the maximum rotation speed (N2max), the rotation speed of the screw shaft (14) of the rotary concentrator (11) is the maximum rotation speed (N3max), or the polymer supply pump (4 ), Even if the rotation speed of the screw shaft (34) of the screw press (31) reaches the minimum rotation speed (N4 min), the screw press (31) is press-fitted. When the pressure (P1) of the concentrated sludge does not return within the range of the reference pressure (P0), an alarm is issued or the operation is stopped, and the rotation speed of the concentrated sludge supply pump (27) is the minimum rotation speed (N2min) Or the rotational speed of the screw shaft (14) of the rotary concentrator (11) is the minimum rotational speed (N3min), or the rotational speed of the polymer feed pump (4) is the maximum rotational speed (N5ma). ), Or even if the rotational speed of the screw shaft (34) of the screw press (31) reaches any of the maximum rotational speeds (N4max), the press-fitting pressure (P1) of the concentrated sludge that is press-fitted into the screw press (31) is the reference. The operation of the screw press connected to the rotary concentrator according to any one of claims 1 to 3, wherein when the pressure does not return within the range of the pressure (P0), an alarm is issued or the operation is stopped. Control method. A concentrated sludge pipe (26) is erected at the discharge part of the rotary concentrator (11), and the reference liquid level (L0) of the concentrated sludge stored in the concentrated sludge pipe (26) while performing press-fitting pressure comparison control, reference rotational speed of the stock solution supply pump for supplying raw sludge (1) (N1), and solution feed reference rotation speed of the pump (1) and (N1) stepwise, setting the value to decrease by rotation speed (n1) When the liquid level (L1) of the concentrated sludge pipe (26) is measured and the liquid level (L1) falls outside the preset reference liquid level (L0), the reference rotation of the stock solution supply pump (1) The liquid level (L1) of the concentrated sludge pipe (26) is controlled within the range of the reference liquid level (L0) by increasing or decreasing the number (N1) stepwise by the rotational speed (n1). The operation control method of the screw press connected with the rotary concentrator of any one of 1-3. The liquid level (L1) of the concentrated sludge stored in the concentrated sludge pipe (26) is measured at regular intervals, and the measured liquid level (L1) of the concentrated sludge pipe (26) is a preset reference liquid level (L0). When it is lower, the reference rotation speed (N1) of the stock solution supply pump (1) is increased by the rotation speed (n1) until the liquid level (L1) of the concentrated sludge rises within the range of the reference liquid level (L0). While repeating this operation, when the measured liquid level (L1) of the concentrated sludge pipe (26) is higher than the preset reference liquid level (L0), the reference rotation speed (N1) of the stock solution supply pump (1) is set to the rotation speed. (n1) only reduces, with the rotary concentrator according to claim 5, characterized in that repeating this operation until the liquid level of the concentrated sludge (L1) falls within the range of the reference liquid level (L0) Operation control method of the screw press to be installed. Even if the rotation speed of the stock solution supply pump (1) reaches the maximum rotation speed (N1max) or the minimum rotation speed (N1min), the liquid level (L1) of the concentrated sludge stored in the concentrated sludge pipe (26) is the reference liquid. The operation control method of the screw press connected to the rotary concentrator according to claim 5 or 6, wherein an alarm is issued or the operation is stopped when it does not return within the range of the position (L0).