JP2020007905A - Operation method for contaminant removal screen device - Google Patents

Abstract

To provide an operation method for contaminant removal screen device capable of removing even a contaminant that can originally pass through an interval between screen members.SOLUTION: An operation method for contaminant removal screen device includes: a supply step (step S11) of feeding sewage water containing a contaminant to a water tank with a pump; a monitoring step (step 12) of monitoring a change in a water level on the upstream side of a screen member; a transfer step (step S13) of transferring the contaminant; and control steps (step S13 to step S17) of controlling a contaminant removal screen device. The control step controls the interval of the screen members so that the interval is gradually blocked by the contaminant that cannot pass through the interval until the water level becomes from a reference water level to a driving water level, and so that the contaminant blocking the interval is removed until the water level is restored from the driving water level to the reference water level.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method for operating a foreign matter removing screen device that captures foreign matter by a screen member and removes the captured foreign matter.

  2. Description of the Related Art Screen devices that remove impurities from incoming water such as sewage containing the impurities are known (for example, see Patent Documents 1 and 2). In this screen device, by performing a transfer drive for transferring impurities trapped without being able to pass through the gap between the screen members provided with an interval connecting the upstream side and the downstream side to the upstream side of the screen member, The contaminants are removed. Impurities captured by the screen member are captured so as to close the gap between the screen members.

JP-A-53-132149 JP-A-2004-183443

  However, in the above-described screen device, foreign substances that have passed through the space between the screen members cannot be removed. Therefore, it is conceivable that the interval between the screen members is narrowed to improve the removal rate of foreign substances. Must be made larger than necessary. In addition, a string-shaped object is likely to pass through even if the above-mentioned interval is narrowed.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a method for operating a foreign matter removing screen device capable of removing even foreign matter that would otherwise pass through the space between screen members.

The operation method of the impurity removing screen device of the present invention that solves the above object,
A transfer for transferring contaminants, which cannot pass through the gap of the screen member provided at an interval connecting the upstream side and the downstream side of the water tank and close the gap on the upstream side of the screen member, on the upstream side of the screen member. In the driving method of the impurity removing screen device for removing the impurity by performing the driving,
Supplying the sewage containing the contaminants to the water tank by a pump,
A monitoring step of monitoring a change in water level on the upstream side of the screen member, from a reference water level located above the lower end of the screen member to a predetermined water level higher than the reference water level,
A transfer step of transferring the contaminants by the transfer drive,
Controlling the impurity removal screen device, and
The transfer step is a step of transferring the contaminants by performing a stepwise transfer of the contaminants as the transfer drive,
The control step controls the transfer drive so that the gap is gradually closed by the contaminants that cannot pass through the gap until the monitored water level becomes the predetermined water level from the reference water level. Until the water level returns from the predetermined water level to the reference water level, the step is a step of controlling the transfer drive so as to remove the contaminants blocking the interval.

  ADVANTAGE OF THE INVENTION According to this invention, the operating method of the foreign material removal screen apparatus which can remove even the foreign material which normally passes through the space | interval of a screen member can be provided.

It is a figure which shows some facilities in a sewage treatment plant typically. It is a front view of the screen system for raw sludge used in one embodiment of the present invention. It is a top view of the screen unit for raw sludge shown in FIG. It is a figure which shows the detail of the overflow unit for drainage. (A) is a schematic diagram of the screen member provided in the impurity removing screen device as viewed from the upstream side of the water tank, and (b) is a diagram illustrating the manner in which the impurity removing screen device 22 removes the impurity in the width direction. FIG. It is a flowchart which shows the flow of the foreign material removal process which the control means of the screen system for raw sludge performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically showing a part of facilities in a sewage treatment plant.

  FIG. 1 shows a sedimentation basin 10, a raw sludge screen unit 20, a scum pit 30, and a scum screen unit 40.

  The sedimentation basin 10 shown in FIG. 1 receives sewage such as sewage or rainwater from one end side in the longitudinal direction (the left side in FIG. 1), sediments the sludge contained in the received sewage at the bottom 1d of the pond, and the other end ( Then drain from the right). Hereinafter, the left direction in FIG. 1 is referred to as upstream, and the right direction in FIG. 1 is referred to as downstream. A sludge pit 11 is provided at a pond bottom 1d on the upstream side of the sedimentation pond 10, and a drain gutter 12 is provided near the water surface on the downstream side. In the sedimentation basin 10, the sludge settled on the bottom 1d of the pond is collected in a sludge pit 11 by a sludge scraper (not shown). The sludge collected in the sludge pit 11 is sent by a sludge pump 111 to a raw sludge screen unit 20 installed outside the sedimentation basin 1. The sludge collected in the sludge pit 11 contains foreign substances such as garbage sinking in water. Hereinafter, the sewage containing sludge sent from the sludge pit 11 to the raw sludge screen unit 20 is referred to as raw sludge. The raw sludge screen unit 20 is a unit for removing impurities contained in the raw sludge, as will be described in detail later. The raw sludge from which the impurities are removed by the raw sludge screen unit 20 is: Then, it is sent to sludge concentration treatment equipment and sludge dewatering treatment equipment. In the sedimentation basin 10, scum floating near the water surface W1 is scraped to the drain gutter 12 by a scum scraper (not shown). The drain gutter 12 is connected to the scum pit 30, and sewage containing scum (scum water) is collected in the scum pit 30, and thereafter, a scum screen installed outside the sedimentation basin 1 from the scum pit 30 by the scum pump 301. It is sent to the unit 40. The scum water collected in the scum pit 30 contains impurities such as dust floating on the water. The scum screen unit 40 is a unit for removing scum, which is an impurity contained in the scum water, and the water from which the scum has been removed by the scum screen unit 40 is returned to the sewage treatment plant. .

  Subsequently, the screen unit 20 for raw sludge will be described as an example, but the same applies to the screen unit 40 for scum.

  FIG. 2 is a front view of the raw sludge screen system used in one embodiment of the present invention.

  The screen system 2 for raw sludge shown in FIG. 2 is provided with the screen unit 20 for raw sludge shown in FIG.

  FIG. 3 is a plan view of the raw sludge screen unit shown in FIG. This plan view corresponds to a view when the raw sludge screen unit 20 is viewed from above.

  The raw sludge screen unit 20 shown in FIGS. 2 and 3 includes a water tank 21, an impurity removing screen device 22, and a water level sensor 23. Each of the raw sludge screen units 20 shown in FIGS. 2 and 3 receives raw sludge from the left side of the figure (see thick arrows in the figures). Hereinafter, the left side in FIGS. 2 and 3 is referred to as upstream, and the right side is referred to as downstream. In addition, a direction perpendicular to the paper surface in FIG. 2 and a vertical direction in FIG. 3 may be referred to as a width direction.

  In the lower half of the upstream side wall of the water tank 21 shown in FIG. 2, there is provided an inclined portion 211 inclined toward the downstream side toward the bottom 21a, and the lower half of the downstream side wall has the bottom 21a. An inclined portion 212 inclined toward the upstream side toward is provided. Therefore, the water tank 21 has a shape in which the bottom 21a side is narrowed. The water tank 21 has three water levels. The lowest water level is the reference water level L1, the highest water level is the emergency water level L3, and the water level higher than the reference water level L1 by a predetermined length (here, 200 mm to 300 mm) is the drive water level L2.

  In the screen unit 20 for raw sludge, an emergency overflow unit 24 is provided on the upstream side, and an overflow unit 25 for drainage is provided on the downstream side. That is, an emergency overflow unit 24 is provided upstream of a screen member provided in the impurity removing screen device 22 described later in detail, and a drain overflow unit 25 is provided downstream. Both the emergency overflow unit 24 and the drain overflow unit 25 have drain basins 241 and 251, and as shown in FIG. 3, both drain basins 241 and 251 are provided so as to project in the width direction of the water tank 21. By opening the canopies 242 and 252, it is possible to look inside. As shown in FIG. 2, the overflow unit 25 for drainage has a weir plate 253 for drainage. The height position of the upper end of the drainage weir plate 253 is slightly lower than the reference water level L1. The sludge collected in the sludge pit 11 is sent to the water tank 21 by driving the sludge pump 111, and the water level in the water tank 21 rises. The drive control of the sludge pump 111 is performed by the control means 50 included in the raw sludge screen system 2. The water level sensor 23 is installed above the emergency water level L3, is an infrared sensor that detects the water level of the water tank 21 using infrared rays, and the detection result is sent to the control means 50. In FIG. 2, the signal lines are represented by dotted lines. The water level sensor 23 may be installed on the bottom 21a instead of a water pressure sensor that detects water pressure. The control means 50 drives the sludge pump 111 continuously until the water level sensor 23 detects that the driving water level 21 has been reached. The sludge pump 111 may be stopped when the detection result of the water level sensor 23 does not change even after the elapse of a predetermined time, or when the sludge scraper installed in the sedimentation basin 10 is stopped.

  4A and 4B are diagrams showing details of the overflow unit for drainage, and FIG. 4A is a schematic diagram of the overflow unit for drainage as viewed from above, and FIG. (C) is a cross-sectional view taken along the line CC ′ of FIG. (A), and FIG. (D) is a view of D in FIG. FIG. 4 is a sectional view taken along the line -D '.

  In FIG. 4A, the left side of the figure is the upstream side of the water tank 21, and the right side is the downstream side of the water tank 21. FIG. 4A shows a side wall 213 of the water tank 21. The side wall 213 is a wall connecting the upstream side and the downstream side of the water tank 21. A rectangular opening 213a is provided in the side wall 213, and a drainage basin 252 is attached to an edge defining the opening 213a. The drainage weir plate 253 is provided at a boundary between the inside of the water tank 21 and the inside of the drainage basin 252. Both end portions of the drainage weir plate 253 are inserted between the side wall 213 and the holding plate 214, and the drainage weir plate 253 is installed below the boundary. The inside of the water tank 21 and the inside of the drainage basin 252 are connected at a portion above the drainage weir plate 253, and are not connected at a part below the drainage weir plate 253. In FIG. 4A, the upper side of the drainage weir plate 253 is on the water tank 21 side, and the lower side of the drainage weir plate 253 is on the drainage basin 252 side. In FIG. 4B, the back side of the paper surface with respect to the drainage weir plate 253 is the water tank 21 side, and the near side of the paper surface with respect to the drainage weir plate 253 is the drainage basin 252 side. 4 (c) and 4 (d), the left side of the drainage weir plate 253 is on the water tank 21 side, and the right side of the drainage weir plate 253 is on the drainage basin 252 side.

  When the water level of the water tank 21 exceeds the height position of the upper end of the drainage weir plate 253, the water in the water tank 21 flows into the drainage basin 252 over the drainage weir plate 253. The state in which the water in the water tank 21 flows into the drainage basin 252 over the drainage dam plate 253 is indicated by a curved arrow in FIG. 4A, and is also illustrated in FIGS. 4C and 4D. . The water in the water tank 21 referred to here is raw sludge that has passed through a screen member provided in the impurity removing screen device 22, that is, sewage containing sludge from which impurities have been removed by the impurity removing screen device 22. The sewage is sent to a sludge concentration treatment facility or a sludge dewatering treatment facility which is a post-treatment process facility. Thus, the raw sludge that has passed through the screen member provided in the impurity removing screen device 22 is drained out of the raw sludge screen unit 20 by the drain overflow unit 25.

  The structure of the emergency overflow unit 24 is the same as the structure of the drain overflow unit 25 described with reference to FIG. 4, but the emergency overflow unit 24 is provided at a position higher than the drain overflow unit 25. As shown in FIG. 2, the emergency overflow unit 24 has an emergency weir plate 243. The height position of the upper end of the emergency weir plate 243 is slightly lower than the emergency water level L3. Therefore, when the water level in the water tank 21 reaches the emergency water level L3, the water in the water tank 21 flows into the drainage basin 242 of the emergency overflow unit 24 over the emergency weir plate 243. The raw sludge in the water tank 21 referred to here is raw sludge before passing through a screen member provided in the impurity removing screen device 22, that is, sludge before impurities are removed by the impurity removing screen device 22. Sewage which is returned to the upstream end of the impurity removing screen device 22. Thus, when the emergency water level L3 is exceeded, the raw sludge in the water tank 21 is once drained out of the raw sludge screen unit 20 by the emergency overflow unit 24. As a case where the water level of the water tank 21 exceeds the emergency water level L3, there is a case where the impurity removing screen device 22 breaks down. In addition, in a combined-type facility that treats rainwater and sewage at the same time, there are cases such as when heavy rain falls or when a large amount of fallen leaves fall in the fall.

  Subsequently, the impurity removing screen device 22 will be described in detail. As shown in FIG. 2, the impurity removing screen device 22 includes a screen member 220, a chain drive mechanism 225, and a chute 227. The chain drive mechanism 225 is driven by rotation of the transfer motor 225m. The rotation of the transfer motor 225m is controlled by the control means 50.

  The screen member 220 is disposed in the water tank 21 in an inclined posture such that the lower part is located on the upstream side of the water tank 21 and the upper part is located on the downstream side. The upper portion of the screen member 220 is provided above the emergency water level L3.

  FIG. 5A is a schematic view of a screen member provided in the impurity removing screen device as viewed from an upstream side of a water tank. The screen member 220 shown in FIG. 2 includes a plurality of pairs of a pair of long fixed screen members 221 and the same long operating screen member 222 provided between the pair of fixed screen members 221. That is, in the impurity removing screen device 22, the fixed screen members 221 and the operating screen members 222 are alternately arranged at predetermined intervals W (for example, 2 mm or more and 6 mm or less) over the entire width of the water tank 21. In FIG. 5A, the screen member 220 at the center in the width direction is omitted to simplify the drawing. The predetermined interval W is an interval connecting the upstream side and the downstream side, which is set based on the balance between the flow rate of the raw sludge passing through the impurity removing screen device 22 and the size of the device. Among the impurities contained in the raw sludge, those that cannot pass through the predetermined interval W are captured by the screen member so as to close the predetermined interval W on the upstream side of the screen member.

  A plurality of fixed steps 2211 are provided on the upstream side of the fixed screen member 221 along the longitudinal direction. On the upstream side of the operation screen member 222, a plurality of operation step portions 2221 are provided along the longitudinal direction. That is, in both the fixed screen member 221 and the operating screen member 222, a step-like step is continuously provided along the longitudinal direction on the upstream side.

  Next, the removal of impurities in the impurity removal screen device 22 will be described. FIG. 5B is a diagram showing a state in which the foreign matter removing screen device 22 removes foreign matters in a stepwise manner from the width direction. In FIG. 5B, the raw sludge flows in from the left side of the figure and flows toward the right side. Therefore, the left side of the figure is the upstream side, and the right side is the downstream side.

  FIG. 5A shows a state in which the operating screen member 222 is at the initial position. The lower part of the fixed screen member 221 is in contact with the bottom 21a of the water tank 21, and the operating screen member 222 in the initial position is at the same height position as the fixed screen member 221. I have. Therefore, the lower part of the operating screen member 222 at the initial position is also in contact with the bottom 21 a of the water tank 21. Further, the foreign substance X is caught from the operation step portion 2221 which is the fifth step from the bottom of the operation screen member 222 shown in (A) to the fixed step portion 2211 which is the fifth step from the bottom of the adjacent fixed screen member 221. I have. The height position of the operation step portion 2221 that is the fifth step from the bottom of the operation screen member 222 shown in (A) and the height position of the fixed step portion 2211 that is the fifth step from the bottom of the fixed screen member 221 are one. I do.

  The operation screen member 222 moves with respect to the fixed screen member 221 when the chain drive mechanism 225 shown in FIG. The operating screen member 222 shown in (a) is moving upward and upstream with respect to the fixed screen member 221, and the operating screen member 222 shown in (c) is just one step above the fixed screen member 221. In the state in which the raw sludge is moved, the raw sludge overlaps the fixed screen member 221 in the flow direction. That is, the height position of the operation step portion 2221 that is the fifth step from the bottom of the operation screen member 222 shown in (C) is at the height position of the fixed step portion 2211 that is the sixth step from the bottom of the fixed screen member 221. The contaminants X are lifted by one step by the operating screen member 222 and are caught by the fixed step portion 2211 which is the sixth step from below the fixed screen member 221. As described above, the foreign matter X caught on the fifth operation step portion 2221 is moved downstream of the fifth operation step portion 2221 in the moving direction of the operation screen member 222 by the movement of the operation screen member 222. It is transferred to the sixth fixed step portion 2211. The moving operation of the operating screen member 222 from (A) to (C) shown in FIG. 5B corresponds to the transfer drive.

  The operating screen member 222 shown in (D) is lower and downstream of the operating screen member 222 shown in (C) while the impurities X are left on the fixed step portion 2211 which is the sixth step from the bottom of the fixed screen member 221. The operating screen member 222 shown in (e) returns to the same height position as the fixed screen member 221 and both overlap when viewed from the width direction. That is, the operating screen member 222 shown in (e) has returned to the initial position. The movement operation of the operating screen member 222 from (c) to (e) shown in FIG. 5B corresponds to a return operation. One cycle of driving such as the transfer driving and the returning operation in the operation screen member 222 is completed by one rotation of the chain member in the chain driving mechanism 225 shown in FIG.

  As described above, the contaminant X is transported upward by one step through the fixed step portion 2211, and finally reaches the uppermost fixed step portion 2211 of the fixed screen member 221. That is, the impurities X are transferred stepwise along the longitudinal direction of the fixed screen member 221. The uppermost fixed step portion 2211 is located above the water surface (emergency water level L3), and impurities reaching the uppermost fixed step portion 2211 are transferred to a chute 227 shown in FIG. It is transported to the input port. The chute 227 has a discharge port 2271 which is open to the outside of the impurity removing screen device 22, and contaminants carried to the input port of the chute 227 are discharged from the discharge port 2271 to the outside of the impurity removing screen device 22. You.

  In the present embodiment, the operating screen member 222 is moved by driving the chain driving mechanism 225. However, by moving the frame without the chain to which the operating screen member 222 is attached, the operating screen member 222 is moved. May be moved.

  Next, the control means 50 of the raw sludge screen system 2 shown in FIG. 2 will be described.

  FIG. 6 is a flowchart showing the flow of the foreign matter removal processing executed by the control means of the raw sludge screen system.

  First, the sludge pump 111 is driven with the transfer motor 225m that drives the chain drive mechanism 225 stopped (step S11). By doing so, the sludge collected in the sludge pit 11 is sent into the water tank 21 as raw sludge, and the raw sludge flows to the impurity removing screen device 22. By executing step S11, the receiving step is executed.

  Next, it is determined whether or not the water level of the water tank 21 has reached the driving water level L2 provided between the reference water level L1 and the emergency water level L3 based on the detection result of the water level sensor 23 (step S12). The process of step S12 is repeatedly executed until L2 is reached, and the driving of the sludge pump 111 is continued. Also in this step S12, the transfer motor 225m is in a stopped state, and the transfer drive by the operating screen member 222 is not performed. As a result, the gap between the fixed screen member 221 and the operating screen member 222 is gradually closed by the foreign substances, and the gap is narrowed by the foreign substances. You can't do that. That is, the next foreign matter is repeatedly caught on the foreign matter caught in the space between the screen members 220. Note that the sludge itself that does not contain impurities is a granular material, and therefore can originally pass through the predetermined interval W shown in FIG. Also, the sewage itself can pass through the predetermined interval W. However, when the distance between the fixed screen member 221 and the operation screen member 222 is reduced by impurities, the flow rate of the sewage itself passing through the screen member 220 per unit time decreases, or even the sludge itself that can originally pass through Although the water cannot pass through the screen member 220 and the drainage is performed by the overflow unit 25 for drainage, the water level in the water tank 21 gradually rises. In other words, with the transfer motor 225m stopped and the sludge pump 111 being driven, the fact that the water level has risen means that even foreign substances that would otherwise pass through the space between the screen members 220 are removed. , Is evidenced by the screen member 220. By performing step S12, the monitoring step according to the present invention is performed.

  When the water level in the water tank 21 reaches the drive water level L2, the rotation of the transfer motor 225m is started (step S13), and the operation screen member 222 starts one cycle of drive such as transfer drive and return operation. Here, the transfer drive is performed for the first time.

  Subsequently, it is determined whether or not the water level in the water tank 21 has not reached the emergency water level L3 based on the detection result of the water level sensor 23. If the water level has not reached the emergency water level L3, the process proceeds to step S15. On the other hand, if the emergency water level L3 has been reached, the sludge pump 111 is stopped (step S16), and the process proceeds to step S15.

  In step S15, it is determined whether or not the water level of the water tank 21 has returned to the reference water level L1 based on the detection result of the water level sensor 23. Until the water level returns to the reference water level L1, the processing in step S14 and the processing in step S15 are performed. Is repeatedly executed, and the rotation of the transfer motor 225m is continued. As a result, the transfer drive by the operation screen member 222 is repeatedly performed until the water level of the water tank 21 returns to the reference water level L1. In the present embodiment, one cycle of driving of the operating screen member 222 is repeated ten or more times per minute.

  By repeatedly performing the transfer drive by the operation screen member 222, the foreign substances caught in the gap between the screen members 220 are removed. As a result, the interval between the screen members 220 returns to the predetermined interval W shown in FIG. 5A, and the flow rate of the sewage itself passing through the screen member 220 increases to the original flow rate. Also, the sludge itself can pass through the screen member 220. Drainage is continued in the overflow unit 25 for drainage, and the water level in the water tank 21 falls to the reference water level L1. According to the experiment of the inventor, the water level in the water tank 21 drops to the reference water level L1 in about 20 seconds to 30 seconds. By performing the above step S13, the transfer step according to the present invention is performed.

  The water level in the water tank 21 should drop to the reference water level L1 in about 20 seconds to 30 seconds. However, when the impurity removing screen device 22 fails and the transfer drive is not performed, or when rainwater and sewage are collected, In a merged facility where water is treated, when heavy rain falls or a large amount of fallen leaves fall in the fall, the water level that should have dropped to the reference water level L1 may reach the emergency water level L3. is there. Therefore, the water level monitoring process in step S14 is performed, and when the emergency water level L3 is reached, the sludge pump 111 is stopped in step S16. When the sludge pump 111 stops, the raw sludge is no longer sent into the water tank 21, further increasing the water level in the water tank 21 is suppressed, and the raw sludge overflows from the water tank 21 by drainage in the emergency overflow unit 24. Has been prevented.

  When the water level in the water tank 21 reaches the reference water level L1, the rotation of the transfer motor 225m is stopped (step S17), and the operation screen member 222 stops. By performing step S17, a stop step is performed. Upon completion of the processing in the step S17, the process returns to the step S12.

  By repeatedly performing step S13 and step S17, it is possible to repeatedly remove even impurities that would otherwise pass through the space between the screen members 220. Further, as the time interval between step S17 and step S12 increases, the driving energy of the transfer motor 225m can be saved.

  In the above description, the raw sludge screen unit 20 has been described as an example. However, the present invention is not limited to a sewage treatment facility, and may be applied to a facility for treating water such as industrial water or agricultural water. it can. In the above description, the transfer drive is a drive for transferring contaminants in a stepwise manner, but may be a drive for continuous transfer (for example, a drive by a belt conveyor or the like).

  Hereinafter, what has been described so far will be additionally described.

(Appendix 1)
A transfer drive for transferring contaminants, which cannot pass through the gap of the screen member provided at an interval connecting the upstream side and the downstream side and close the gap on the upstream side of the screen member, on the upstream side of the screen member. By performing, in the operation method of the impurity removal screen device for removing the impurities,
A receiving step of receiving water with the transfer drive stopped,
A monitoring step of monitoring the water level during the receiving step,
When the water level being monitored reaches a drive water level higher than a reference water level, the transfer drive is started, and a transfer step of transferring the contaminants,
A stopping step of stopping the transfer drive when the monitored water level returns to the reference water level, the method for operating a contaminant removal screen device.

  According to the operating method of the impurity removing screen device described in Appendix 1, the transfer drive is not performed until the drive water level is reached. Then, the gap between the screen members is gradually closed by the foreign matter, and the gap is narrowed by the foreign matter, so that even the foreign matter that would otherwise pass through cannot be passed. That is, the next foreign matter is repeatedly caught by the foreign matter caught in the space between the screen members. When this happens, the flow rate of the incoming water passing through the screen device decreases, the water level gradually rises, and eventually reaches the driving water level. Here, for the first time, the transfer drive is performed, the foreign matter caught in the gap between the screen members is removed, the flow rate of the receiving water passing through the screen device increases to the original flow rate, and the water level drops to the reference water level. In this way, by repeatedly performing the transfer step and the stop step, it is possible to repeatedly remove even impurities that would otherwise pass through the space between the screen members. Further, as the time interval between the stopping step and the transferring step increases, the driving energy of the impurity removing screen device can be saved.

  The operation method of the impurity removing screen device can be applied not only to a sewage treatment facility but also to a facility that treats water such as industrial water or agricultural water. Further, the transfer drive may be a drive for transferring contaminants stepwise, or may be a drive for continuous transfer (for example, a drive by a belt conveyor).

  Further, in the operating method of the impurity removing screen device described in Supplementary Note 1, the transferring step is a step of transferring the impurity by moving an operating screen member provided between the pair of fixed screen members. You may.

  Further, in the operating method of the impurity removing screen device according to Supplementary Note 1, the transporting step may be a step of transporting the impurity stepwise along the longitudinal direction of the fixed screen member.

(Appendix 2)
Water level monitoring means for monitoring the water level in the water tank;
Contaminants that cannot pass through the gap of the screen member provided with an interval connecting the upstream side and the downstream side of the water tank and close the gap on the upstream side of the screen member are transferred on the upstream side of the screen member. A contaminant removal screen device for removing the contaminants by performing a transfer drive;
Control means for controlling the transfer drive of the impurity removing screen device,
When the water level being monitored by the water level monitoring means reaches a driving water level higher than a reference water level, the control means starts the transfer drive, and the water level being monitored by the water level monitoring means returns to the reference water level. Then, the transfer drive is stopped.

  According to the screen system described in Supplementary Note 2, the operation method of the foreign matter removing screen device described in Supplementary Note 1 can be performed, and even the foreign matter that would otherwise pass through the space between the screen members is removed. be able to.

  In addition, the water level monitoring means may monitor a water level in a water tank provided with a drainage port downstream of the impurity removing screen device.

  In addition, in the screen system described in Supplementary Note 2, the impurity removing screen device is provided between a pair of fixed screen members and the pair of fixed screen members, and an operating screen member that moves with respect to the fixed screen members. And the contaminants may be transferred by moving the operating screen member.

Furthermore, in the screen system described in Supplementary Note 2, the fixed screen member is provided with a plurality of fixed steps along the longitudinal direction,
The operating screen member is provided with a plurality of operating steps along the longitudinal direction,
The contaminant removal screen device, the contaminants caught on the operating step, by moving the operating screen member, to the fixed step on the moving direction downstream of the operating screen member from the operating step. It may be transferred.

(Appendix 3)
A transfer for transferring contaminants, which cannot pass through the gap of the screen member provided at an interval connecting the upstream side and the downstream side of the water tank and close the gap on the upstream side of the screen member, on the upstream side of the screen member. In the driving method of the impurity removing screen device for removing the impurity by performing the driving,
A monitoring step of monitoring a change in water level on the upstream side of the screen member, from a reference water level located above the lower end of the screen member to a predetermined water level higher than the reference water level,
A transfer step of transferring the contaminants by the transfer drive,
Controlling the impurity removal screen device, and
The transfer step is a step of transferring the contaminants by performing a stepwise transfer of the contaminants as the transfer drive,
The control step controls the transfer drive so that the gap is gradually closed by the contaminants that cannot pass through the gap until the monitored water level becomes the predetermined water level from the reference water level. Operating the transfer drive so as to remove the contaminants blocking the gap until the water level returns from the predetermined water level to the reference water level. Method.

(Appendix 4)
The method according to claim 3, wherein the reference water level is set to a water level at which the received water starts to be drained from the water tank.

(Appendix 5)
The transferring step moves the operating screen member provided between the pair of fixed screen members, thereby transferring the contaminants stepwise along the longitudinal direction of the fixed screen member, and A step of repeatedly executing one cycle of driving of the operating screen member, in which the operating screen member is moved upward and upstream with respect to the member and then returned downward and downstream. 5. The method for operating the impurity removing screen device according to 3 or 4.

(Appendix 6)
The monitoring step is a step of monitoring a change in the water level on the upstream side of the screen member from the predetermined water level to an emergency water level higher than the predetermined water level,
The said control step is a step also including the step which stops the reception of the water to the said water tank when the said water level has reached the said emergency water level, Any one of Additional notes 3-5 characterized by the above-mentioned. Method for operating the screen device for removing impurities.

(Appendix 7)
A transfer for transferring contaminants, which cannot pass through the gap of the screen member provided at an interval connecting the upstream side and the downstream side of the water tank and close the gap on the upstream side of the screen member, on the upstream side of the screen member. By performing driving, a contaminant removal screen device for removing the contaminants,
Water level monitoring means for monitoring a change in water level on the upstream side of the screen member, from a reference water level located above the lower end of the screen member to a predetermined water level higher than the reference water level,
Control means for controlling the impurity removing screen device,
The contaminant removal screen device performs a drive for transferring the contaminants stepwise as the transfer drive,
The control means controls the transfer drive so that the gap is gradually closed by the contaminants that cannot pass through the gap until the monitored water level becomes the predetermined water level from the reference water level. A screen system for controlling the transfer drive so as to remove the contaminants blocking the interval until the water level returns from the predetermined water level to the reference water level.

(Appendix 8)
The screen system according to claim 7, wherein the reference water level is set to a water level at which the received water starts to be drained from the water tank.

(Appendix 9)
The contaminant removal screen device includes a pair of fixed screen members, an operating screen member provided between the pair of fixed screen members and moving with respect to the fixed screen members,
The fixed screen member is provided with a plurality of fixed steps along the longitudinal direction,
The operating screen member is provided with a plurality of operating steps along the longitudinal direction,
The contaminant removal screen device is configured to transfer the contaminants stepwise along the longitudinal direction of the fixed screen member by moving the operating screen member, and is caught on the operating step portion. The contaminants are transferred to the fixed step portion above the operation step portion by moving the operation screen member upward and upstream, and then the operation screen member returns downward and downstream, 9. The screen system according to claim 7 or 8, wherein one cycle of driving of the operating screen member is repeatedly executed.

(Appendix 10)
The water level monitoring means also monitors a change in water level on the upstream side of the screen member from the predetermined water level to an emergency water level higher than the predetermined water level,
The control unit, wherein the water level being monitored by the water level monitoring unit stops receiving water to the water tank when the water level reaches the emergency water level, any one of supplementary notes 7 to 9. The screen system according to 1.

(Appendix 11)
A transfer for transferring contaminants, which cannot pass through the gap of the screen member provided at an interval connecting the upstream side and the downstream side of the water tank and close the gap on the upstream side of the screen member, on the upstream side of the screen member. In the driving method of the impurity removing screen device for removing the impurity by performing the driving,
A monitoring step of monitoring a change in water level on the upstream side of the screen member, from a reference water level located above the lower end of the screen member to a predetermined water level higher than the reference water level,
A transfer step of transferring the contaminants by the transfer drive,
Controlling the impurity removal screen device, and
The monitoring step is a step of monitoring a change in the water level on the upstream side of the screen member from the predetermined water level to an emergency water level higher than the predetermined water level,
The control step controls the transfer drive so that the gap is gradually closed by the contaminants that cannot pass through the gap until the monitored water level becomes the predetermined water level from the reference water level. Until the water level returns from the predetermined water level to the reference water level, the step of controlling the transfer drive so as to remove the contaminants blocking the interval, further comprising: setting the water level to the emergency water level. The method for operating a contaminant removal screen device, further comprising the step of stopping the reception of water into the water tank when the water reaches the water tank.

(Appendix 12)
A transfer for transferring contaminants, which cannot pass through the gap of the screen member provided at an interval connecting the upstream side and the downstream side of the water tank and close the gap on the upstream side of the screen member, on the upstream side of the screen member. By performing driving, a contaminant removal screen device for removing the contaminants,
Water level monitoring means for monitoring a change in water level on the upstream side of the screen member, from a reference water level located above the lower end of the screen member to a predetermined water level higher than the reference water level,
Control means for controlling the impurity removing screen device,
The water level monitoring means also monitors a change in water level on the upstream side of the screen member from the predetermined water level to an emergency water level higher than the predetermined water level,
The control means controls the transfer drive so that the gap is gradually closed by the contaminants that cannot pass through the gap until the monitored water level becomes the predetermined water level from the reference water level. Until the water level returns from the predetermined water level to the reference water level, the transfer drive is controlled so as to remove the contaminants blocking the interval, and further, the water level becomes the emergency water level. A screen system for stopping reception of water into the aquarium when the water tank reaches the water tank.

(Appendix 13)
The raw sludge containing contaminants collected in the sedimentation basin cannot pass through the gap of the screen member provided with an interval connecting the upstream side and the downstream side of the tank to which the raw sludge containing impurities is supplied. By performing a transfer drive to transfer the foreign matter closing the gap on the upstream side of the screen member, in the operating method of the foreign matter removal screen device for removing the foreign matter,
A monitoring step of monitoring a change in water level on the upstream side of the screen member, from a reference water level located above the lower end of the screen member to a predetermined water level higher than the reference water level,
A transfer step of transferring the contaminants by the transfer drive,
Controlling the impurity removal screen device, and
The monitoring step is a step of monitoring a change in the water level on the upstream side of the screen member from the predetermined water level to an emergency water level higher than the predetermined water level,
The control step controls the transfer drive so that the gap is gradually closed by the contaminants that cannot pass through the gap until the monitored water level becomes the predetermined water level from the reference water level. A second control for controlling the transfer drive so that the interval is widened when the water level is the predetermined water level, and the second control is continued until the water level becomes the reference water level from the predetermined water level And further comprising, when the water level reaches the emergency water level, stopping the receiving of the raw sludge into the water tank. Driving method.
(Appendix 14)
The transferring step moves the operating screen member provided between the pair of fixed screen members, thereby transferring the contaminants stepwise along the longitudinal direction of the fixed screen member, and A step of repeatedly executing one cycle of driving of the operating screen member, in which the operating screen member is moved upward and upstream with respect to the member, and then returned downward and downstream. 14. The method for operating the impurity removing screen device according to 13 above.
(Appendix 15)
The raw sludge containing contaminants collected in the sedimentation basin cannot pass through the gap of the screen member provided with an interval connecting the upstream side and the downstream side of the tank to which the raw sludge containing impurities is supplied. By performing a transfer drive for transferring the foreign matter closing the gap on the upstream side of the screen member, a foreign matter removing screen device that removes the foreign matter,
Water level monitoring means for monitoring a change in water level on the upstream side of the screen member, from a reference water level located above the lower end of the screen member to a predetermined water level higher than the reference water level,
Control means for controlling the impurity removing screen device,
The water level monitoring means also monitors a change in water level on the upstream side of the screen member from the predetermined water level to an emergency water level higher than the predetermined water level,
The control means controls the transfer drive so that the gap is gradually closed by the contaminants that cannot pass through the gap until the monitored water level becomes the predetermined water level from the reference water level. A second control for controlling the transfer drive so that the interval is widened when the water level is the predetermined water level, and the second control is continued until the water level becomes the reference water level from the predetermined water level A screen system for stopping receiving the raw sludge into the water tank when the water level reaches the emergency water level.
(Appendix 16)
The contaminant removal screen device includes a pair of fixed screen members, an operating screen member provided between the pair of fixed screen members and moving with respect to the fixed screen members,
The fixed screen member is provided with a plurality of fixed steps along the longitudinal direction,
The operating screen member is provided with a plurality of operating steps along the longitudinal direction,
The contaminant removal screen device is configured to transfer the contaminants stepwise along the longitudinal direction of the fixed screen member by moving the operating screen member, and is caught on the operating step portion. The contaminants are moved to the fixed step portion above the operation step portion by moving the operation screen member upward and upstream, and then the operation screen member returns downward and downstream, 16. The screen system according to claim 15, wherein one cycle of driving the operating screen member is repeatedly executed.

111 Sludge pump 2 Screen system for raw sludge 20 Screen unit for raw sludge 21 Water tank 22 Impurity removing screen device 220 Screen member 221 Fixed screen member 2211 Fixed step 222 Operation screen member 2221 Operation step 225 Chain drive mechanism 225m Transfer motor 227 Chute 23 Water level sensor 24 Emergency overflow unit 25 Drain overflow unit 251 Drain basin 253 Drainage weir plate 50 Control means L1 Reference water level L2 Drive water level L3 Emergency water level X Impurities

Claims (1)

A transfer for transferring contaminants, which cannot pass through the gap of the screen member provided at an interval connecting the upstream side and the downstream side of the water tank and close the gap on the upstream side of the screen member, on the upstream side of the screen member. In the driving method of the impurity removing screen device for removing the impurity by performing the driving,
Supplying the sewage containing the contaminants to the water tank by a pump,
A monitoring step of monitoring a change in water level on the upstream side of the screen member, from a reference water level located above the lower end of the screen member to a predetermined water level higher than the reference water level,
A transfer step of transferring the contaminants by the transfer drive,
Controlling the impurity removal screen device, and
The transfer step is a step of transferring the contaminants by performing a stepwise transfer of the contaminants as the transfer drive,
The control step controls the transfer drive so that the gap is gradually closed by the contaminants that cannot pass through the gap until the monitored water level becomes the predetermined water level from the reference water level. Operating the transfer drive so as to remove the contaminants blocking the gap until the water level returns from the predetermined water level to the reference water level. Method.