JP6919426B2 - How to operate the sludge concentrator and sludge concentrator system - Google Patents

Description

The present invention relates to an operating method of a sludge concentrator for filtering and concentrating clean water sludge, and a sludge concentrating system.

Clean water sludge is sludge that is settled and deposited at the bottom of a sedimentation pond by adding a flocculant to raw water such as river water and groundwater in a water purification facility that produces drinking water, and because it contains a large amount of water. It is once concentrated by gravity, and further concentrated by a final dehydration step such as a filter press or a sun dryer. In this way, sludge concentrated to a predetermined concentration or higher can be reclaimed or recycled as horticultural soil.

Further, as a pretreatment for the final dehydration step, the concentrated sludge is further concentrated and dehydrated by a sludge concentrator using a filter cloth or a membrane. By improving the apparent capacity of the final dehydration process by such pretreatment, it is possible to expect cost reductions such as downsizing of filter presses and sun dryers and reduction of the number of installed units.

Inventions related to such a technique include a container, a filter membrane installed inside the container, a filtrate discharge means extending from the filter membrane to the outside of the container, and a difference between the primary side and the secondary side of the filter membrane. A differential pressure generating means for generating pressure, a suspension supplying means for supplying the suspension into the container, a suspension discharging means for discharging the suspension in the container, and a residue adhering to the filtration membrane are filtered. In a filtration concentrator having a residue peeling means for peeling from the film and a residue discharging means for discharging the peeled residue to the outside of the container, a plurality of batches of filtration were performed in advance, and the suspension discharge water level rate at which the residual concentration was the highest. A technique for performing filtration under conditions is known (see, for example, Patent Document 1).

In addition, the amount of raw water supplied to the membrane separation device is kept constant, and the amount of permeated water for setting the sludge concentration of concentrated water to a predetermined target value based on the sludge concentration of raw water measured by the sludge concentration meter is set. A technique is known in which the output of the suction pump is feed-forward controlled so that the calculated value of the flow meter arranged in the pipeline becomes the calculated permeated water amount (see, for example, Patent Document 2).

However, in the above technique, control based on the suction pressure from the downstream side of the filter cloth or the membrane, which affects the sludge treatment efficiency in the sludge concentrator using the filter cloth or the membrane, is not performed. It cannot be said that the sludge treatment efficiency by the sludge concentrator is always high.

Japanese Unexamined Patent Publication No. 2008-21768 Japanese Unexamined Patent Publication No. 2003-164870

An object of the present invention in view of such a current situation is to provide a technique capable of higher sludge treatment efficiency in the control of a sludge concentrator for performing a sludge concentration treatment of clean water sludge.

The present invention for achieving the above object includes a tank for taking in raw water containing sludge, and a tank for taking in raw water.
A filter body that is immersed in the raw water of the tank, separates sludge from the raw water, and concentrates the sludge on the surface.
A method of operating a sludge concentrator including a suction device for sucking raw water in the tank through the filter body.
Obtaining information on the suction pressure of the suction device,
This is an operation method of a sludge concentrator that controls the suction flow rate of the suction device so as to correspond to the acquired information on the suction pressure.

According to this, when the suction device sucks the raw water through the filter body of the sludge concentrator, separates the sludge from the raw water, and concentrates the sludge on the surface of the filter, the sludge treatment efficiency is greatly affected. Since the suction flow rate is controlled so as to correspond to the suction pressure, the sludge treatment efficiency can be further increased.

Further, in the present invention, the suction pressure information is the value of the suction pressure, and the suction flow rate of the suction device may be controlled to be a predetermined value corresponding to the value of the suction pressure. .. According to this, for example, the relationship between the suction flow rate and the suction pressure, which improves the sludge treatment efficiency, is determined in advance by an experiment or the like, and the relationship is stored. Then, when the sludge concentrator is in operation, the suction pressure value is acquired, the suction flow rate value corresponding to each suction pressure value is read out in the above relationship, and the suction flow rate by the suction device is read out to the read value. Control. Such simple control makes it possible to increase the efficiency of sludge treatment by the sludge concentrator.

Further, in the present invention, the suction flow rate is controlled by feedback control so that the value of the suction pressure becomes a predetermined target value at that time (for example, so as to change linearly with time). You may do so. According to this, it is possible to control the suction flow rate more accurately so that the value of the suction pressure changes a predetermined value (for example, changes linearly with time). As a result, it becomes possible to more reliably increase the sludge treatment efficiency by the sludge concentrator.

Further, in the present invention, the suction pressure information is information indicating a change in suction pressure.
The suction flow rate of the suction device may be controlled to increase or decrease according to the information indicating the change in the suction pressure. According to this, the suction flow rate can be controlled (using a differential component) according to the amount of change in the suction pressure, so that the control response can be accelerated, the value of the suction flow rate can be set earlier, and the suction pressure can be adjusted. It is possible to control the value corresponding to the information.

Further, in the present invention, the suction flow rate corresponding to the suction pressure information may be determined according to the properties of sludge in the raw water.

Here, the optimum suction flow rate value for each suction pressure value during operation of the sludge concentrator differs depending on the sludge properties. Therefore, by controlling the suction flow rate so that it corresponds to the value of the suction pressure and further corresponds to the properties of sludge in the raw water, the sludge treatment efficiency by the sludge concentrator can be improved more reliably. Is possible.

The property of the sludge may be the sludge concentration in the raw water or the viscosity of the sludge. If the sludge concentration or sludge viscosity changes, the amount of sludge that can be treated changes with the same suction pressure. Therefore, by controlling the suction flow rate according to the sludge concentration or the viscosity of the sludge, it is possible to increase the sludge treatment efficiency more reliably.

Further, in the present invention, from the state in which the sludge on the surface of the filter body is peeled off, until the suction pressure of the suction device reaches a predetermined value by accumulating the sludge on the surface of the filter body by filtering the raw water. When 1 cycle of filtration operation is performed
The suction flow rate corresponding to the suction pressure information may be set so that the total suction flow rate in one cycle of filtration operation is a predetermined amount or more.

According to this, the suction flow rate can be controlled according to the relationship between the suction pressure and the suction flow rate so that the total suction flow rate in the one-cycle filtration operation of the sludge concentrator becomes a predetermined amount or more, and more reliably. It is possible to secure the amount of sludge processed in one cycle of filtration operation of the sludge concentrator.

Further, the predetermined amount may be the total amount of suction flow rates such that the amount of sludge accumulated on the surface of the filter body is equal to or more than the second predetermined amount. According to this, the suction flow rate is controlled according to the relationship between the suction pressure and the suction flow rate so that the amount of sludge accumulated on the surface of the filter body becomes the second predetermined amount or more in the one-cycle filtration operation of the sludge concentrator. Can be done. As a result, it is possible to more reliably secure the amount of sludge accumulated in one cycle of operation of the sludge concentrator.

Further, in the present invention, from the state in which the sludge on the surface of the filter body is peeled off, until the suction pressure of the suction device reaches a predetermined value by accumulating the sludge on the surface of the filter body by filtering the raw water. When 1 cycle of filtration operation is performed
The suction flow rate corresponding to the suction pressure information may be set so that the operation time in one cycle of filtration operation is a predetermined time or less.

Here, it is known that the exfoliation property of the concentrated sludge differs depending on the time of one cycle of the sludge concentrator. More specifically, it has been found that when the time of one cycle of the sludge concentrator is too long, the exfoliation property of the sludge accumulated on the surface of the filter body deteriorates. Therefore, according to the present invention, by setting the time of one cycle of the sludge concentrator to be less than a predetermined time, it is possible to optimize the releasability of the sludge accumulated and concentrated on the surface of the filter body. It is possible to improve the work efficiency of sludge concentration treatment.

Further, in the present invention, the predetermined value corresponding to the suction pressure value is
With respect to a predetermined suction pressure range including the value of the suction pressure, the total suction flow rate in the suction pressure range may be a value determined so as to be equal to or more than a third predetermined amount.

According to this, in the predetermined suction pressure range, the suction flow rate is set so that the total suction flow rate is equal to or more than the third predetermined amount, and by combining a plurality of sets of the suction pressure range and the suction flow rate, a wider suction flow can be performed. It is possible to increase the total value of the suction flow rate as much as possible with respect to the entire pressure range. This makes it possible to more reliably improve the sludge treatment efficiency in a wider suction pressure range.

Further, the present invention includes a tank for taking in raw water containing sludge.
A filter body that is immersed in the raw water of the tank, separates sludge from the raw water, and concentrates the sludge on the surface.
A suction device that sucks the raw water in the tank through the filter body,
It may be a sludge concentration system including a control device that acquires information on the suction pressure of the suction device and controls the suction flow rate of the suction device so as to correspond to the acquired information on the suction pressure.

The means for solving the problems in the present invention can be used in combination as much as possible.

In the present invention, it is possible to further increase the sludge treatment efficiency in the control of the sludge concentrator for performing the sludge concentration treatment of clean water sludge.

It is the schematic of the clean water sludge concentrator which concerns on embodiment of this invention. It is the schematic of the filter cloth which concerns on embodiment of this invention. It is the schematic of the filter cloth element which concerns on embodiment of this invention. It is a graph which shows the example of the change of the suction pressure and the suction flow rate at the time of suction by a filtered water suction pump in the clean water sludge concentrator according to the Example of this invention. This is the first measurement example of the suction pressure / flow rate curve according to the embodiment of the present invention. This is a second measurement example of the suction pressure / flow rate curve according to the embodiment of the present invention.

The best embodiments for carrying out the present invention will be illustrated in detail below with reference to the drawings.

<Example 1>
FIG. 1 is a diagram showing a schematic configuration of a clean water sludge concentrator 1 in this embodiment. The clean water sludge concentrator 1 in this embodiment collects the concentrated sludge concentrated in the raw sludge tank 2 for temporarily storing the raw sludge M to which the coagulant is added, the concentrated sludge 3 for concentrating and precipitating the raw sludge M, and the concentrated sludge 3. It includes a sun-drying bed 5 for drying, a control unit 8 for controlling the device, and a pressure sensor 9.

Here, the configuration of the concentration tank 3 for concentrating and precipitating the raw sludge M will be described in detail. The concentrating tank 3 is provided with a plurality of filter cloth elements 4 provided with a filter cloth 40 as a filter body for filtering the raw sludge M. FIG. 2 shows a schematic view of the filter cloth 40. 2 (a) is a front view, FIG. 2 (b) is a side view, and FIG. 2 (c) is a top view. As can be seen from FIG. 2, the filter cloth 40 is formed in a bag shape and has an envelope-like shape that is substantially rectangular when viewed from the front. On the filter cloth surface 40a, the raw sludge M can be filtered and the sludge can be separated. Further, an upper opening 40c and a lower opening 40d are provided above and below the filter cloth 40, and the raw sludge M is sucked from the inside of the filter cloth 40 through the upper opening 40c and the lower opening 40d. The raw sludge M is filtered, and the filtered liquid after filtration can be discharged to the outside through the upper opening 40c and the lower opening 40d.

FIG. 3 shows a schematic view of the filter cloth element 4. FIG. 3A is a front view of the filter cloth element 4, and FIG. 3B is a top view. As shown in FIG. 3, the filter cloth element 4 of this embodiment is provided with five filter cloths 40. The filter cloth element 4 has a frame 4a provided so as to surround the five filter cloths 40 from the periphery in the front view of FIG. 3 (a). The frame 4a is made of metal and is formed of a hollow tubular member. Suction ports 4b and 4c capable of sucking the fluid inside the filter cloth 40 are provided at the upper left and right ends in the front view.

Further, the upper side of the frame 4a is provided with five upper connection ports 4d that can be connected to the upper opening 40c of the filter cloth 40. Further, the lower side of the frame 4a is provided with five lower connection ports 4e that can be connected to the lower opening 40d of the filter cloth 40. The upper opening 40c of the filter cloth 40 and the upper connection port 4d of the frame 4a are connected in a state where the inside is communicated with each other, and are fastened by a fastening member (not shown) so that the fluid flowing inside does not leak. The lower opening 40d of the filter cloth 40 and the lower connection port 4e of the frame 4a are also connected in the same manner, and are fastened by a fastening member (not shown).

Further, three partition plates 4f, 4g, and 4h are provided inside the frame 4a, and the flow of fluid is blocked on both sides of the partition plates 4f, 4g, and 4h. In this state, by sucking from the suction ports 4b and 4c, the raw sludge M can be filtered from the inside of the filter cloth 40 through both the lower opening 40d and the upper opening 40c of the five filter cloths 40. It is possible.

Next, the description of FIG. 1 is returned to. In FIG. 1, the raw sludge M from the drainage pond of clean water is temporarily stored in the raw sludge tank 2. The stored raw sludge M is pumped from the raw sludge tank 2 to the concentration tank 3 by the raw sludge pump 6. The concentrating tank 3 is provided with a plurality of filter cloth elements 4, and the raw sludge M can be sucked from the inside of the filter cloth 40 by the filtered water suction pump 7. By sucking the raw sludge M from the inside of the filter cloth 40 attached to each filter cloth element 4 with the filtered water suction pump 7, the raw sludge M in the concentration tank 3 is removed from each filter cloth surface 40a to each filter cloth 40. It is sucked inside.

At that time, the raw sludge M is filtered by the filter cloth 40, and only the filtrate moves inside each filter cloth 40. After that, the filtrate passes through the upper opening 40c and the lower opening 40d of the filter cloth 40, the upper connection port 4d and the lower connection port 4e of the frame 4a, the suction ports 4b and 4c, and is sucked to the filtered water suction pump 7. Will be done. Then, the filtrate passes through the filtered water suction pump 7 and is drained or collected. At that time, concentrated sludge remaining after the raw sludge M is filtered is deposited on the filter cloth surface 40a.

Then, in the clean water sludge concentrator 1, air is sent from the upper opening 40c and the lower opening 40d of the filter cloth 40 through the suction ports 4b and 4c by a compressor (not shown) at a predetermined timing. By doing so, air is ejected from the inside of the filter cloth 40 through the filter cloth surface 40a to the outside of the filter cloth 40, and the concentrated sludge accumulated on the filter cloth surface 40a falls off from the filter cloth 40, and the concentration tank 3 is used. Accumulate on the bottom. Then, the concentrated sludge accumulated on the bottom surface of the concentrating tank 3 is discharged to the sun-dried bed 5, dried by being exposed to the sun on the sun-dried bed 5, and then disposed of.

The control unit 8 controls the raw sludge pump 6 and the filtered water suction pump 7. The control unit 8 may be composed only of an electric circuit including a drive circuit of pumps and a detection circuit of a pressure sensor 9, or may be composed of a computer system having a CPU and a storage device. A pressure sensor 9 for detecting the suction pressure is electrically connected to the control unit 8. Then, the control of the filtered water suction pump 7 may be performed manually by the user using the control unit 8 while observing the suction pressure detected by the pressure sensor 9 and displayed on the control unit 8. Further, it may be performed by automatic control based on the program stored in the storage device included in the control unit 8, the control data, and the detection data by the pressure sensor 9.

Next, the relationship between the suction pressure and the suction flow rate that change depending on the operation of the filtered water suction pump 7 will be described. FIG. 4 shows a diagram of temporal changes in suction pressure and suction flow rate due to the operation of the filtered water suction pump 7 in the clean water sludge concentrator 1 (hereinafter, also referred to as a suction pressure / flow rate curve). When the raw sludge M in the concentrating tank 3 is filtered by suctioning from the inside of the filter cloth 40 with the filtered water suction pump 7, the suction pressure is conventionally constant as shown in FIG. 4A. In some cases, the filtered water suction pump 7 was operated as described above. Then, the concentrated sludge is deposited on the filter cloth surface 40a, the suction flow rate is sharply reduced, the suction flow rate is extremely reduced in a short time, and the sludge treatment efficiency is extremely lowered.

Further, conventionally, as shown in FIG. 4B, the filtered water suction pump 7 may be operated so that the suction flow rate becomes constant. In this case, the concentrated sludge was deposited on the filter cloth surface 40a, the suction pressure was sharply reduced (the negative pressure was increased), and the suction pressure was lowered to the set pressure within a short time. As a result, it was necessary to temporarily finish the sludge treatment within a short period of time and remove the concentrated sludge accumulated on the filter cloth surface 40a. Then, the amount of sludge that can be treated by sucking the filtrate to the set pressure with the filtered water suction pump 7 becomes extremely small, and in this case as well, there is a problem that the sludge treatment efficiency is extremely lowered.

On the other hand, in this embodiment, as shown in FIG. 4C, the raw sludge M is sucked while changing the suction flow rate according to the value of the suction pressure. That is, after the start of suction by the filtered water suction pump 7, the suction flow rate is changed according to the suction pressure value so that the suction pressure value gradually decreases (negative pressure gradually increases), and the set pressure ( Here, it was decided to increase the total suction flow rate until it reaches about −40 KPa) to improve the sludge treatment efficiency. The set pressure may be the rated ultimate pressure of the filtered water absorption pump 7. In this embodiment, after the suction pressure drops to the set pressure and the operation of the filtered water suction pump 7 is stopped, air is injected into the filter cloth 40 by the compressor to deposit on the filter cloth surface 40a. Remove the concentrated sludge. This series of operations is one cycle of sludge concentration treatment.

Here, the value of the suction flow rate used when changing the suction flow rate according to the value of the suction pressure was determined by the following method. The range of suction pressure from atmospheric pressure to the set pressure was divided into a plurality of minute suction pressure ranges, the suction flow rate in each minute suction pressure range was changed, and one cycle of filtration operation was performed a plurality of times. From the results of multiple 1-cycle filtration operations, a set of minute suction pressure range and suction flow rate in that suction pressure range is taken out, and the total suction flow rate, sludge peelability, drop time from the start of suction filtration to the set pressure, etc. In combination, one cycle of filtration operation was performed again so as to satisfy the desired parameter conditions. By repeating this, in one cycle of filtration operation, a set of a minute suction pressure range and suction flow rate (corresponding to the third predetermined amount) that can satisfy the conditions of each parameter, that is, the relationship between the suction pressure and the suction flow rate is determined. Furthermore, the optimum combination was determined.

The total suction flow rate may be set so that the total suction flow rate in one cycle of filtration operation is equal to or greater than a predetermined amount. Regarding the exfoliation property of sludge, the amount of sludge accumulated on the filtration surface in one cycle of filtration operation is set to a second predetermined amount or more so that sludge can obtain good exfoliation property from the filter cloth. It may be determined to be. On the other hand, the descent time from the start of suction filtration to the set pressure may be set to be a practical operation time. Further, the operation time may be set so as to be a practical operation time and a good sludge removability from the filter cloth can be obtained.

Here, according to the diligent research of the inventors, in the above-mentioned one-cycle sludge concentration treatment, the total suction flow rate in the one-cycle sludge concentration treatment can be made as much as possible by appropriately changing the suction flow rate according to the suction pressure. It has been found that it is possible to optimize the properties of concentrated sludge in addition to being able to increase the amount of sludge. These points will be described in detail below.

FIG. 5 shows a suction pressure / flow rate curve when the suction flow rate is controlled to a value corresponding to the suction pressure so that the suction pressure drops linearly. FIG. 5 is a graph when the suction pressure is changed so as to reach −40 kPa within 30 minutes from the start of suction filtration. In FIG. 5, when the filter cloth area is about 3 m ² , about 10 L of concentrated sludge is filtered by a total suction flow rate of about 90 L in one cycle of sludge concentration treatment for sludge having a raw sludge concentration of about 1.0%. It could be deposited on cloth 40. In this way, by appropriately selecting the time from the start of suction filtration to the drop of the suction pressure to the set pressure and controlling the suction flow rate based on the relationship between the suction pressure and the suction flow rate, a sufficient total suction flow rate and concentration can be achieved. It was found that the amount of sludge was obtained and sufficient sludge treatment efficiency could be obtained.

Next, FIG. 6 shows a suction pressure / flow rate curve when a larger total suction flow rate and sludge amount are secured. FIG. 6A is a graph when the suction pressure is changed so as to reach −40 kPa within 60 minutes from the start of suction filtration. FIG. 6B is a graph when the suction pressure is changed so as to reach −40 kPa in 120 minutes from the start of suction filtration.

In FIG. 6A, when the filter cloth area is about 3 m ² , about 20 L of sludge is concentrated by a total suction flow rate of about 170 L in one cycle of sludge concentration treatment for sludge having a raw sludge concentration of about 1.0%. Sludge could be deposited on the filter cloth 40. Further, in FIG. 6B, in one cycle of sludge concentration treatment for sludge having a raw sludge concentration of about 1.0%, about 20 L of concentrated sludge can be deposited on the filter cloth 40 with a total suction flow rate of about 170 L. did it. In this way, under the conditions that the filter cloth area is about 3 m ² and the raw sludge concentration is about 1.0%, for example, when the total suction flow rate is 150 L or more and 15 L or more of sludge is deposited on the filter cloth 40 at that time. It was found that the suction pressure / flow rate curve as shown in FIG. 6 should be adopted for this. In this embodiment, 150 L corresponds to a predetermined amount of the total suction flow rate, and 15 L corresponds to a second predetermined amount of sludge to be accumulated.

In general, the range of raw sludge concentration at which the technique of the present invention can be used is about 0.1% by mass or more and 15% by mass or less. More preferably, it is about 0.5% by mass or more and 10% by mass or less. More preferably, it is about 1% by mass or more and about 5% by mass or less.

On the other hand, in the one-cycle sludge concentration treatment based on FIG. 6, it was found that when the suction pressure drops for a long time, the sludge exfoliation property when the concentrated sludge is removed from the filter cloth 40 deteriorates. More specifically, when the suction pressure drops for a long time, the water content at the boundary between the filter cloth 40 and the concentrated sludge is large, and the filter cloth surface 40a after the concentrated sludge has fallen off is contaminated. It is presumed that this is because the suction flow rate at the start of filtration became a low value because the rate of decrease in the suction pressure was slowed down, and the sludge was not consolidated in the initial sludge capture by the filter cloth 40. In this embodiment, under the conditions that the filter cloth area is about 3 m ² and the raw sludge concentration is about 1.0%, the sludge peeling is practically sufficient by setting the operation time in one cycle of filtration operation to 90 minutes or less. I was able to get sex. In this embodiment, the value of 90 minutes of operation time corresponds to a predetermined time.

Next, the automatic operation in this embodiment will be described. In the automatic operation, the suction flow rate is controlled based on the predetermined relationship between the suction pressure and the suction flow rate while the suction pressure is changed from the atmospheric pressure to the set pressure. In this automatic operation, the relationship between the suction pressure and the suction flow rate is stored in advance in the storage device of the control unit 8 of the clean water sludge concentrator 1, the suction pressure is detected by the pressure sensor 9, and the detected suction pressure. It may be by a program that operates the filtered water suction pump 7 so that the suction flow rate corresponds to the above. As a result of the automatic operation, one cycle of filtration operation could be reproduced stably and accurately.

(Effect of sludge properties)
Next, the relationship between the results obtained in the sludge concentration treatment and the concentration of raw sludge as a property of sludge will be described. When the concentration of raw sludge changes, the amount of sludge that accumulates on the filter cloth surface 40a changes when the sludge is sucked at the same suction flow rate, so the maximum amount of accumulated sludge can be obtained (the sludge treatment efficiency is the highest). The suction pressure / flow rate curve also changes.

In this embodiment, when the raw sludge concentration is high, a large amount of concentrated sludge tends to accumulate on the filter cloth surface 40a even if the suction flow rate is the same, so that the suction flow rate corresponding to the same suction pressure range is reduced. Set. On the contrary, when the raw sludge concentration is low, the concentrated sludge tends not to be deposited so much on the filter cloth surface 40a even if the suction flow rate is the same, so a large suction flow rate corresponding to the same suction pressure range is set. However, if the suction flow rate is excessively increased because the raw sludge concentration is low, the filter cloth may be immediately blocked due to the influence of the coagulant. In that case, it was found that good treatment efficiency can be obtained by securing a total suction flow rate of a predetermined amount or more according to the concentration of the raw sludge while suppressing the suction flow rate.

Next, the relationship between the results obtained in the sludge concentration treatment and the viscosity of the sludge as a property will be described. Here, the properties of sludge vary depending on the composition, season, weather, temperature, etc. of the raw sludge in each water purification facility. For example, a coagulant whose amount is appropriately adjusted according to the composition, season, weather, temperature, etc. of the raw sludge is injected into the clean water sludge. This causes the clean water sludge to become viscous. If the suction flow rate is excessively increased when the viscosity of the sludge is high as described above, the filter cloth 40 is rapidly blocked and the sludge deposited on the filter cloth surface 40a is poorly peelable. In addition, sludge in the summer has a high temperature and therefore has a low viscosity, and sludge in the winter has a low temperature and a high viscosity. While controlling the suction flow rate based on the relationship between the suction pressure and the suction flow rate,
By controlling the suction flow rate according to the sludge properties, it is possible to obtain good treatment efficiency.

<Example 2>
Next, Example 2 of the present invention will be described. This embodiment changes the point that the relationship between the suction pressure and the suction flow rate of the first embodiment is predetermined. In this embodiment, the description of the parts common to those in the first embodiment will be omitted. In this embodiment, the control device acquires information on the suction pressure at a predetermined timing from the start to the end of the suction, and controls the suction flow rate according to the acquired information. As an example, the information on the suction pressure is the information on the suction pressure, and the suction flow rate is controlled so as to be a predetermined suction pressure according to the time from the suction start time. In this way, the suction pressure changes linearly with the passage of time, and it becomes possible to improve the sludge treatment efficiency by the sludge concentrator. Further, as another example, the information regarding the suction pressure is the information indicating the change in the suction pressure, and the suction flow rate of the suction device is controlled so as to increase or decrease according to the information indicating the change in the suction pressure. In this way, the suction flow rate can be controlled (using a differential component) according to the amount of change in the suction pressure, so that the control response can be accelerated and the suction flow rate value can be set earlier. It is possible to control the value corresponding to the information of. Here, in order to perform these controls with high accuracy, feedback control or the like may be incorporated.

In the automatic operation in this embodiment, the suction flow rate is adjusted by feedback control with respect to the information indicating the change in the suction pressure so that the suction pressure becomes the target value along the linear descending line.

The filter cloth and the filter cloth element to which the present invention is applied are not limited to those shown in FIGS. 2 and 3. It goes without saying that the present invention can be applied to filter cloths and filter cloth elements prepared with other shapes and specifications. Further, in the above embodiment, the example in which the clean water sludge concentrator 1 is provided with the control unit 8 and the pressure sensor 9 has been described, but the clean water sludge concentrator 1 is provided with the control unit 8 or the pressure sensor 9. Instead, these may be prepared separately.

1 ... Clean water sludge concentrator 2 ... Raw sludge tank 3 ... Concentration tank 4 ... Filter cloth element 5 ... Sun-dried floor 6 ... Raw sludge pump 7 ... Filter Water suction pump 8 ・ ・ ・ Control unit 9 ・ ・ ・ Pressure sensor 40 ・ ・ ・ Filter cloth M ・ ・ ・ Raw sludge F ・ ・ ・ Filter liquid

Claims (4)

A tank that takes in raw water containing sludge,
A filter body that is immersed in the raw water of the tank, separates sludge from the raw water, and concentrates the sludge on the surface.
A method of operating a sludge concentrator including a suction device for sucking raw water in the tank through the filter body.
Obtaining information on the suction pressure of the suction device,
The suction flow rate of the suction device is controlled so as to correspond to the acquired information on the suction pressure .
One cycle of filtration operation is performed from the state in which the sludge on the surface of the filter body is peeled off until the suction pressure of the suction device reaches a predetermined value due to the accumulation of the sludge on the surface of the filter body by filtering the raw water. If you do
The suction flow rate corresponding to the suction pressure information is determined according to the viscosity of the sludge in the raw water.
Further, the total suction flow rate in one cycle of filtration operation is set to be a predetermined amount or more, and the predetermined amount is such that the amount of sludge accumulated on the surface of the filter body is a second predetermined amount or more. How to operate the sludge concentrator, which is a large amount. A tank that takes in raw water containing sludge,
A filter body that is immersed in the raw water of the tank, separates sludge from the raw water, and concentrates the sludge on the surface.
A method of operating a sludge concentrator including a suction device for sucking raw water in the tank through the filter body.
Obtaining information on the suction pressure of the suction device,
The suction flow rate of the suction device is controlled so as to correspond to the acquired information on the suction pressure.
One cycle of filtration operation is performed from the state in which the sludge on the surface of the filter body is peeled off until the suction pressure of the suction device reaches a predetermined value due to the accumulation of the sludge on the surface of the filter body by filtering the raw water. If you do
The suction flow rate corresponding to the suction pressure information is determined according to the viscosity of sludge in the raw water.
Further, an operation method of a sludge concentrator in which an operation time in one cycle of filtration operation is defined to be a predetermined time or less. A tank that takes in raw water containing sludge,
A filter body that is immersed in the raw water of the tank, separates sludge from the raw water, and concentrates the sludge on the surface.
A method of operating a sludge concentrator including a suction device for sucking raw water in the tank through the filter body.
Obtaining information on the suction pressure of the suction device,
The suction flow rate of the suction device is controlled so as to be a predetermined value corresponding to the acquired value of the suction pressure.
The predetermined value corresponding to the suction pressure value is determined according to the viscosity of the sludge in the raw water.
Further, it is characterized in that the total suction flow rate in the suction pressure range is a value determined so as to be equal to or more than a third predetermined amount with respect to a predetermined suction pressure range including the value of the suction pressure. How to operate the sludge concentrator. A tank that takes in raw water containing sludge,
A filter body that is immersed in the raw water of the tank, separates sludge from the raw water, and concentrates the sludge on the surface.
A suction device that sucks the raw water in the tank through the filter body,
A sludge concentration system comprising a control device that acquires information on the suction pressure of the suction device and controls the suction flow rate of the suction device so as to correspond to the acquired information on the suction pressure .
The control device is
One cycle of filtration operation is performed from the state in which the sludge on the surface of the filter body is peeled off until the suction pressure of the suction device reaches a predetermined value due to the accumulation of the sludge on the surface of the filter body by filtering the raw water. If you do
The suction flow rate corresponding to the suction pressure information is determined according to the viscosity of sludge in the raw water.
Further, control that determines the total suction flow rate in one cycle of filtration operation so that the amount of sludge accumulated on the surface of the filter body is equal to or greater than the second predetermined amount.
or,
One cycle of filtration operation is performed from the state in which the sludge on the surface of the filter body is peeled off until the suction pressure of the suction device reaches a predetermined value due to the accumulation of the sludge on the surface of the filter body by filtering the raw water. If you do
The suction flow rate corresponding to the suction pressure information is determined according to the viscosity of sludge in the raw water.
Further, control that sets the operation time in one cycle of filtration operation to be less than a predetermined time,
or,
A predetermined value corresponding to the suction pressure value is determined according to the viscosity of sludge in raw water.
Further, control for determining the total suction flow rate in the suction pressure range to be equal to or greater than the third predetermined amount with respect to the predetermined suction pressure range including the value of the suction pressure.
A sludge concentration system characterized by performing any of the above.

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