JP4016352B2 - Membrane filtration device - Google Patents

Description

  The present invention relates to a membrane filtration treatment apparatus installed for separating and removing turbidity and pathogenic protozoa contained in raw water.

  The membrane filtration apparatus is installed in a water purification facility that purifies raw water represented by surface water such as rivers. The membrane filtration apparatus has a filtration membrane that separates and removes turbidity, pathogenic protozoa and the like (hereinafter collectively referred to as turbidity) contained in raw water.

  In such a membrane filtration processing apparatus, filtration, backwashing, chemical washing, and the like are repeated, so that the filtration membrane may break. When the filtration membrane breaks, untreated raw water leaks from the broken portion of the filtration membrane, so that turbidity is mixed into the filtered water.

  In order to prevent turbidity from being mixed into the filtered water, the turbidity of the filtered water is measured with a measuring instrument, and the breakage of the filtration membrane is detected based on the measured turbidity (for example, patents). Reference 1).

JP-A-10-128086

  By the way, when raw water with relatively low turbidity (for example, underground water, groundwater) is filtered, or when the ratio of the broken part to the normal part of the filter membrane is small, the filtered water when the filter membrane is broken Turbidity is also relatively small. However, since instruments that measure turbidity generally have a certain limit in detection sensitivity, the turbidity of filtered water may not be measured with a measuring instrument in the method as in Patent Document 1. . As a result, even when a rupture occurs in the filtration membrane, the rupture may not be detected.

  An object of the present invention is to realize a membrane filtration apparatus that is more suitable for accurately detecting the breakage of a filtration membrane.

In order to solve the above problems, the membrane filtration apparatus of the present invention includes a membrane filtration means having a filtration membrane for separating and removing turbidity contained in raw water, and a water quality measurement for measuring the turbidity of filtrate water of the membrane filtration means. Means, a membrane rupture detection means for detecting the rupture of the filtration membrane based on the measurement value of the water quality measurement means, and a filtration flow rate changing means for adjusting the flow rate of the raw water passing through the filtration membrane based on a command from the membrane rupture detection means, The membrane breakage detecting means outputs a command to reduce the passage flow rate to the filtration flow rate changing means to reduce the flow rate of the raw water passing through the filtration membrane, and the measured value taken from the water quality measurement means after the reduction of the passage flow rate Based on the above, it is characterized by detecting the breakage of the filtration membrane.

  That is, when the flow rate through the filtration membrane with the breakage is reduced, the amount of water passing through the normal portion of the filtration membrane is reduced due to a decrease in the water pressure with respect to the filtration membrane, whereas the amount of water passing through the breakage portion is The decrease is smaller than the normal part. Here, the raw water that passes through the broken portion is untreated, and therefore contains a relatively large amount of turbidity. Therefore, the turbidity of the filtered water after the reduction of the passage flow rate increases more than before the reduction.

  Based on such knowledge, the turbidity of filtered water can be increased by decreasing the passing flow rate when detecting the breakage of the filtration membrane. As a result, for example, even when the turbidity of the raw water is relatively small, the turbidity of the filtered water can be accurately detected regardless of the detection sensitivity of the turbidity measuring instrument, so that the accuracy of detecting the breakage of the filtration membrane is improved. Therefore, since it becomes appropriate to take measures when the breakage occurs, it is easy to always supply safe and safe purified water. In addition, turbidity here is the ratio of the turbidity per unit volume.

In this case, the membrane breakage detection means outputs a command to reduce the passage flow rate to the filtration flow rate change means, acquires the measurement value of the water quality measurement means before reducing the passage flow rate as the first measurement value, and passes the flow rate. The measured value of the water quality measuring means after the decrease is obtained as the second measured value, and it can be determined that the filter membrane has been broken when the second measured value is larger than the first measured value. As a result, when judging the presence or absence of membrane rupture, the turbidity difference before and after the decrease in the flow rate of the flow is used as a reference, so it is not affected by the turbidity of the raw water itself, and the leakage of the filtration membrane is accurately detected. it can.

Further, the membrane breakage detecting means outputs a command to reduce the passage flow rate to the filtration flow rate changing means to obtain the measurement value of the water quality measurement means after reducing the passage flow rate, and the obtained measurement value is less than the set value. When it is large, it can be determined that the filter membrane is broken. Thereby, when determining the presence or absence of a film rupture, since the set value which is a threshold is used as a reference, the film rupture detection process can be simplified.

The membrane breakage detecting means can output a command for returning the passage flow rate to the original amount to the filtration flow rate changing means when it is determined that the filtration membrane is not broken. Thereby, since the operation | movement of a membrane filtration process can be continued, the operation stop time accompanying a membrane fracture | rupture detection process can be shortened.

Also, a treated water quality measuring means for measuring the turbidity of the raw water upstream of the membrane filtering means is provided, and the membrane breakage detecting means is used as a filtration flow rate changing means when the measured value of the treated water quality measuring means is less than a set value. A command for reducing the passage flow rate can be output to reduce the passage flow rate. Thereby, since the case where a film | membrane break detection process should be started can be detected automatically, the usability of an apparatus improves.

Also, a plurality of membrane filtration means and filtration flow rate changing means are provided, the water quality measurement means measures the turbidity after merging of treated water flowing out from each membrane filtration means, and the membrane breakage detection means includes a plurality of membrane breakage detection means . Of the filtration flow rate changing means, a command for decreasing the passage flow rate can be output to one filtration flow rate changing means to reduce the passage amount of one membrane filtration means. Thereby, since the presence or absence of the membrane rupture can be detected in order for each of the plurality of membrane filtration means, it is possible to specify the membrane filtration means in which the membrane rupture has occurred.

In addition, the membrane breakage detection means outputs a command to increase the passage flow rate to the other filtration flow rate change means while reducing the passage flow rate of one membrane filtration means among the plurality of membrane filtration means. The passage flow rate of the means can be increased. Thereby, since reduction of the amount of treated water resulting from reducing a passage flow rate can be compensated, the desired amount of treated water can be secured.

  The membrane filtration method of the present invention includes a filtration step of separating and removing turbidity contained in raw water with a filtration membrane, a water quality measurement step of measuring the turbidity of filtered water that has passed through the filtration membrane, and a water quality measurement step. A membrane rupture detection step that detects the rupture of the filtration membrane based on the measured value. The membrane rupture detection step reduces the flow rate of the raw water that passes through the filtration membrane, and takes the measurement taken from the water quality measuring means after the passage flow rate is reduced. Based on the value, the filter membrane is detected to be broken.

  ADVANTAGE OF THE INVENTION According to this invention, the more suitable membrane filtration processing apparatus is realizable by detecting the fracture | rupture of a filtration membrane exactly. For example, even when the turbidity of the raw water is relatively small, the turbidity of the filtered water can be accurately detected, so that the accuracy of detecting the breakage of the filtration membrane is improved.

(First embodiment)
A first embodiment of a membrane filtration apparatus to which the present invention is applied will be described. When the membrane filtration treatment device of the present embodiment detects the breakage of the filtration membrane, when the flow rate through the filtration membrane is temporarily reduced, the turbidity of the filtered water is improved if the filtration membrane is broken. It is realized based on the knowledge that More specifically, the membrane filtration apparatus of this embodiment reduces the flow rate of raw water that passes through the filtration membrane, and detects the breakage of the filtration membrane based on the turbidity of the filtrate water after the reduction of the flow rate. .

  Below, the membrane filtration apparatus of this embodiment is demonstrated by the 1st thru | or 4th Example. However, it can be changed as necessary, for example, by combining or replacing the components and modifications described in each embodiment.

(Example 1-1)
FIG. 1 is a diagram showing a first example of a membrane filtration apparatus according to the first embodiment to which the present invention is applied. The membrane filtration processing apparatus of this embodiment is installed in a purification facility or the like that purifies raw water represented by surface water such as rivers. As shown in FIG. 1, such a membrane filtration apparatus has a membrane filtration means 1 having a filtration membrane for separating and removing turbidity contained in raw water, and a filtration flow rate change for adjusting the flow rate of raw water passing through the filtration membrane. Means 2, a water quality measuring means (hereinafter, treated water quality measuring means 3) for measuring the turbidity of the filtered water of the membrane filtration means 1, and a membrane breakage for detecting the breakage of the filtration membrane based on the measured values of the treated water quality measuring means 3. The control means 4 etc. as a detection means are provided.

  And the control means 4 applied to the membrane filtration processing apparatus of a present Example reduces the flow volume of raw | natural water (henceforth a passage flow rate suitably) which passes a filtration membrane to the filtration flow volume change means 2, and after the passage flow volume decreases, Based on the measured value taken from the treated water quality measuring means 3, it has a function of detecting breakage of the filtration membrane.

  In more detail, the membrane filtration apparatus of a present Example is demonstrated. The membrane filtration means 1 is mounted with a filtration membrane that removes turbidity, fine particles and the like in the raw water. The filtration membrane is processed in units of modules configured by incorporating thousands of hollow fiber membranes. Such a filtration membrane is preferable for introduction into a water purification facility because it can substantially remove fine particles larger than the pore size of the membrane and is easy to maintain.

  The filtration flow rate changing means 2 is arranged in series upstream of the membrane filtration means 1. However, the filtration flow rate changing means 2 may be arranged on the downstream side of the membrane filtration means 1. Such filtration flow rate changing means 2 has a pump or the like that changes the filtration flux of the membrane filtration means 1. Further, the treated water quality measuring means 3 is disposed on the downstream side of the membrane filtration means 1. In addition, the highly sensitive turbidimeter is employ | adopted as the treated water quality measurement means 3 of a present Example.

  The control means 4 has a function of taking a measurement signal from the treated water quality measuring means 3, a function of outputting a flow rate change command to the filtration flow rate changing means 2, and whether or not the filtration membrane of the membrane filtration means 1 is broken. It has the function to judge.

  The basic operation of the membrane filtration apparatus configured as described above will be described. First, raw water (for example, surface water, underground water, groundwater) is supplied to the membrane filtration means 1. When the supplied raw water passes through the filtration membrane, turbidity in the raw water is separated and removed. The filtered water flowing out from the membrane filtration means 1 is supplied to a subsequent water treatment facility.

  Here, the operation for detecting the breakage of the filtration membrane will be described. The control means 4 takes in the measured value A of turbidity from the treated water quality measuring means 3 as the first measured value when the membrane filtration apparatus is performing a basic operation.

  Next, when detecting the breakage of the filtration membrane, the control means 4 outputs a command for reducing the passage flow rate of the membrane filtration means 1 to the filtration flow rate changing means 2. The filtration flow rate changing means 2 reduces the passage flow rate in response to a decrease command from the control means 4. Then, the control means 4 takes in the turbidity measurement value B from the treated water quality measurement means 3 as the second measurement value. In addition, what is necessary is just to set so that the water quality after the reduction | decrease of a passage flow rate can be reflected in the measurement value B about the time from the time of reducing a passage flow amount until acquiring measurement value B. For example, the acquisition time of the measured value B may be determined based on the pipe length from the filtration flow rate changing unit 2 to the treated water quality measuring unit 3 or the passing flow rate.

  Next, the control means 4 compares the measurement value A with the measurement value B, and detects the breakage of the filtration membrane based on the comparison result. More specifically, when the measured value B is larger than the measured value A, the control means 4 interprets that raw water is leaking from the ruptured portion of the filtration membrane, and determines that the rupture has occurred in the filtration membrane. To do. In that case, the control means 4 outputs a command to make the passage flow rate zero to the filtration flow rate changing means 2. The filtration flow rate changing means 2 makes the passage flow rate zero according to the command of the control means 4. When the measurement value B is equal to or less than the measurement value A, the control unit 4 determines that the filtration membrane is not broken, and outputs a command to restore the passage flow rate to the filtration flow rate changing unit 2.

  In short, when detecting the breakage of the filtration membrane, the control means 4 of the present embodiment temporarily decreases the flow rate of the raw water passing through the filtration membrane, and each of the turbidity of the filtrate water before and after the decrease (for example, measured value) A and measured value B) are acquired, and when measured value B is larger than measured value A, it is determined that the filter membrane has been broken.

  That is, when the passage flow rate of the filtration membrane in which breakage occurs is reduced, the amount of water passing through the normal portion of the filtration membrane decreases due to a decrease in water pressure on the filtration membrane, whereas the amount of water passing through the breakage portion is The decrease is smaller than the normal part. Here, the raw water that passes through the broken portion is untreated, and therefore contains a relatively large amount of turbidity. Therefore, the turbidity per unit volume of filtered water after the reduction of the passage flow rate will increase more than before the reduction.

  According to the present embodiment based on such knowledge, the turbidity of filtered water can be increased by decreasing the passing flow rate when detecting the breakage of the filtration membrane. As a result, for example, even when the turbidity of the raw water is relatively small, the turbidity of the filtered water can be accurately detected regardless of the detection sensitivity of the turbidity measuring instrument, so that the accuracy of detecting the breakage of the filtration membrane is improved. Therefore, since it becomes appropriate to perform a treatment on the filter membrane in which breakage has occurred, it is easy to supply safe and safe purified water. In addition, turbidity here is the ratio of the turbidity per unit volume.

  In addition, according to the present embodiment, when determining the presence or absence of membrane breakage, since it is based on the magnitude of the difference in turbidity before and after the reduction of the passage flow rate, it is not affected by the turbidity of the raw water itself, and the filtration membrane Can be accurately detected.

  Here, the relationship between the passage flow rate and the turbidity of the filtered water will be supplemented with reference to FIG. FIG. 2 is an example of measuring the change in turbidity of filtered water relative to the passing flow rate. The vertical axis in FIG. 2 indicates the turbidity of filtrate (filtrate turbidity), and the horizontal axis indicates the filtration flux corresponding to the passing flow rate. In addition, when acquiring the measured value of FIG. 2, every time the hollow fiber membrane of the filtration membrane was cut | disconnected by predetermined amount, the raw | natural water with the same turbidity was allowed to pass through a filtration membrane.

  As shown in FIG. 2, the turbidity of the filtrate is gradually reduced as the filtration flux is increased. In other words, when the filtration flux is decreased, the turbidity of the filtered water gradually increases. Based on the knowledge obtained from such measurement results, the membrane filtration apparatus of the present embodiment is realized. That is, the membrane filtration processing apparatus of the present embodiment can improve the membrane breakage detection sensitivity by the turbidity measurement of the treated water quality measuring means 3 by reducing the filtration flux, that is, the passing flow rate.

  As described above, the membrane filtration apparatus of the present embodiment has been described, but the present invention is not limited to this. For example, when the measured values of the treated water quality measuring means 3 vary, the control means 4 obtains, for example, a plurality of measured values A from the treated water quality measuring means 3, and sets the average value of the obtained measured values A as the first measured value. Can be obtained as Regarding the measurement value B, the average value of the plurality of measurement values B can be acquired as the second measurement value. Moreover, the control means 4 holds the set value in consideration of the variation in the measurement value by the treated water quality measurement means 3, and the deviation between the measurement value B and the measurement value A (measurement value B-measurement value A) exceeds the set value. In this case, it can be determined that the filter membrane is broken. Thereby, even when the measured value of the treated water quality measuring means 3 varies, for example, the measured value drifts due to aging deterioration, the error included in the measured value can be reduced.

  Further, the control means 4 compares the preset upper limit value H with the measured value B instead of comparing the measured value A with the measured value B. And the control means 4 can interpret that the raw | natural water has leaked from the fracture | rupture part of a filtration membrane, when the measured value B exceeds the upper limit H, and can detect the fracture | rupture of a filtration membrane. Thereby, when determining the presence or absence of a film rupture, since the set value which is a threshold is used as a reference, the film rupture detection process can be simplified.

  In addition, when the control means 4 determines that there is no breakage in the filtration membrane, the flow rate is restored, so that the operation of the membrane filtration process can be continued, so that the operation stop time associated with the membrane breakage detection process can be shortened. . Further, the control means 4 can increase the passing flow rate more than the original amount instead of returning the passing flow rate to the original. Thereby, since the reduction | decrease of the total amount of treated water resulting from having stopped the membrane filtration means 1 temporarily can be compensated, a predetermined treated water amount can be ensured.

  Further, when a storage tank is provided on the downstream side of the membrane filtration means 1 and a breakage of the filtration membrane is detected, the filtrate water flowing out from the membrane filtration means 1 can be temporarily stored in the storage tank. Thereby, when the turbidity of filtrate water rises resulting from the fracture | rupture of a filtration membrane, it can prevent supplying the filtrate water to a water treatment installation of a back | latter stage. Moreover, it replaces with storing filtered water in a storage tank, and you may increase the addition amount of the disinfectant for reducing turbidity.

  Moreover, the control means 4 can hold | maintain the setting value S about the turbidity of filtered water, and when the measured value of the measurement means 3 is more than the setting value S, it can start the fracture | rupture detection process of a filtration membrane. The set value S here is set to a value smaller than the upper limit value H when the upper limit value H is set. Moreover, the control means 4 can start the filtration membrane breakage detection process at a predetermined time and a predetermined interval.

  As a conventional rupture detection method, there is a method of filling a pressurized gas at the time of backwashing and detecting the rupture of the filtration membrane based on a change in the flow rate of the pressure (for example, Japanese Patent Laid-Open No. 2000-93765). However, in this method, since the detection process is executed every time the backwashing is performed, even if a rupture occurs in the filtration membrane, there occurs a time lag that the rupture is not detected until the next backwashing. In this regard, according to the present embodiment, the rupture of the filtration membrane can be detected online by the start process based on the set value S. Moreover, since the start time or the start interval can be set freely, it is possible to detect the breakage of the filtration membrane as needed.

  In addition, the membrane breakage detection method using the membrane filtration apparatus of the present embodiment includes a filtration step for separating and removing turbidity contained in raw water with a filtration membrane, and a water quality for measuring the turbidity of filtered water that has passed through the filtration membrane. A measurement step, and a membrane breakage detection step for detecting breakage of the filtration membrane based on the measurement value of the water quality measurement step. And the membrane breakage detection step reduces the flow rate of the raw water passing through the filtration membrane, and detects the breakage of the filtration membrane based on the measured value taken from the water quality measuring means after the passage flow rate is reduced. .

  As described above, according to the present embodiment, the turbidity of the filtrate flowing out from the membrane filtration means 1 is increased, the sensitivity of the membrane breakage detection by the treated water quality measurement means 3 is improved, and a membrane that supplies safer and safer purified water. A method for operating the filtration apparatus can be provided.

(Example 1-2)
FIG. 3 is a diagram showing a second example of the membrane filtration apparatus of the first embodiment to which the present invention is applied. The membrane filtration processing apparatus of the present embodiment is different from the embodiment 1-1 in that the membrane breakage detection process is started based on the measurement value of the treated water quality measurement means 5 installed on the upstream side of the membrane filtration means 1. The treated water quality measuring means 5 here is a turbidimeter that measures the turbidity of the raw water supplied to the membrane filtration means 1, and transmits the measured value to the control means 4.

  The film break detection process of the present embodiment will be described. First, the control means 4 takes the measured value A of turbidity from the treated water quality measuring means 3 at a predetermined interval when the membrane filtration apparatus is performing a basic operation. Next, the control means 4 compares the preset lower limit L with the measured value A. When the measured value A is less than or equal to the lower limit L, the control means 4 has relatively low turbidity in the raw water to be treated. The film break detection process is started. The contents of the film break detection process are the same as those in Example 1-1.

  In addition, when it is over a long time that the measured value A falls below the lower limit value L, the control unit 4 may start the process at a preset frequency. In other words, the filtration flow rate changing means 2 can also intermittently reduce the passing flow rate in accordance with the command of the control means 4.

  According to the present embodiment, in addition to the effects described in Embodiment 1-1, a case where the raw water turbidity to be treated is relatively small can be automatically detected by the treated water quality measuring means 5. That is, it is possible to automatically detect when the film break detection process should be started. As a result, the breakage of the filtration membrane can be accurately detected, and the usability of the apparatus is improved.

(Example 1-3)
FIG. 4 is a diagram showing a third example of the membrane filtration apparatus of the first embodiment to which the present invention is applied. The membrane filtration processing apparatus of the present embodiment differs from that of Example 1-1 in that a plurality of the membrane filtration means 1 and the filtration flow rate changing means 2 of FIG. In the present embodiment, an example in which three membrane filtration means 1 and three filtration flow rate changing means 2 are arranged will be described, but the number may be increased as appropriate.

  As shown in FIG. 4, the membrane filtration means 1-1 to 1-3 are arranged in parallel. The filtration flow rate changing means 2-1 to 2-3 are provided on the upstream side of the membrane filtration means 1-1 to 1-3. For example, the filtration flow rate changing means 2-1 is provided in series upstream of the membrane filtration means 1-1. The treated water quality measuring means 3 measures the turbidity after joining the treated water flowing out from the membrane filtration means 1-1 to 1-3.

  When the membrane breakage detection process of the present embodiment is started, the control means 4 takes in the measured value A of turbidity from the treated water quality measurement means 3. Next, the control means 4 outputs a command for decreasing the passage flow rate of the membrane filtration means 1-1 to the filtration flow rate changing means 2-1. The filtration flow rate changing means 2-1 decreases the passage flow rate of the membrane filtration means 1-1 according to the command of the control means 4. Next, the control unit 4 takes in the turbidity measurement value B <b> 1 from the treated water quality measurement unit 3. The time from when the passage flow rate is reduced until the measurement value B is acquired is set so that the water quality after the reduction of the passage flow rate can be reflected in the measurement value B.

  And the control means 4 compares the measured value A and measured value B1, and when measured value B1 is larger than measured value A, it determines with the fracture | rupture having arisen in the filtration membrane of the membrane filtration means 1-1. In that case, the control means 4 outputs the instruction | command which makes the passage flow rate of the membrane filtration means 1-1 to zero to the filtration flow rate change means 2-1. When the measurement value B1 is equal to or less than the measurement value A, the control means 4 determines that the filtration membrane of the membrane filtration means 1-1 is not broken, and gives a command to restore the passage flow rate to the filtration flow rate change means 2 Output to -1. Although the example which detects the fracture | rupture of the filtration membrane of the membrane filtration means 1-1 was demonstrated typically, the case of the membrane filtration means 1-2 and 1-3 is also the same.

  When such membrane breakage detection processing is executed in order for each of the membrane filtration means 1-1 to 1-3, the membrane filtration means (for example, the membrane filtration means 1-1) in which the filtration membrane is broken can be accurately identified. . Thereby, even when a plurality of membrane filtration means 1-1 to 1-3 are provided, in addition to the effect described in the embodiment 1-1, the membrane filtration means to be stopped (for example, the membrane filtration means 1- 1) can be specified accurately, so it is easy to supply clean and safe water.

  Moreover, if the control means 4 specifies the membrane filtration means 1-1 in which the filtration membrane broke among the plurality of membrane filtration means 1-1 to 1-3, for example, the other membrane filtration means 1-2, 1 -3 is output to the overflow rate changing means 2-2 and 2-3. Thereby, since the reduction | decrease of the filtrate water resulting from stopping the membrane filtration means 1-1 can be compensated, predetermined | prescribed amount of treated water is securable. Further, a spare membrane filtration means may be provided, and for example, when the membrane filtration means 1-1 is stopped, the spare membrane filtration means may be temporarily operated.

(Example 1-4)
FIG. 5 is a diagram showing a fourth example of the membrane filtration apparatus of the first embodiment to which the present invention is applied. The membrane filtration treatment apparatus of the present embodiment is the first embodiment in that the membrane breakage detection process is started based on the measurement value of the treated water quality measurement means 5 installed on the upstream side of the membrane filtration means 1-1 to 1-3. -3. The treated water quality measuring means 5 here is a turbidimeter that measures the turbidity of the raw water that is branched and supplied to the membrane filtration means 1-1 to 1-3, and transmits the measured value to the control means 4. .

  That is, as shown in FIG. 5, the membrane filtration treatment apparatus of the present example is provided with the treated water quality measuring means 5 of Example 1-2 in the membrane filtration treatment apparatus of Example 1-3, A function for controlling the water quality measuring means 5 is implemented in the control means 4. Therefore, according to the present embodiment, in addition to the effects described in Embodiment 1-3, a case where the raw water turbidity to be treated is relatively small can be automatically detected by the treated water quality measuring means 5. In other words, it is possible to automatically detect when the film break detection process should be started. As a result, the breakage of the filtration membrane can be accurately detected, and the usability of the apparatus is improved.

( Reference example )
A reference example of a membrane filtration apparatus to which the present invention is applied will be described. The membrane filtration apparatus of the present reference example differs from the first embodiment in that a turbidity source is added to raw water when detecting the breakage of the filtration membrane. More specifically, the membrane filtration treatment apparatus of this reference example adds a turbidity source to the raw water upstream of the membrane filtration means, and performs filtration based on the turbidity of filtrated water taken after the addition of the turbidity source. Detect film breaks.

Below, the membrane filtration apparatus of this reference example is demonstrated by the 1st thru | or 4th Example. However, it can be changed as necessary, for example, by combining or replacing the constituent parts and modifications described in each example or the first embodiment. Note that differences from the first embodiment will be mainly described, and portions corresponding to each other will be omitted as appropriate.

(Example 2-1)
FIG. 6 is a diagram showing a first embodiment of a membrane filtration apparatus of a reference example to which the present invention is applied. As shown in FIG. 6, the turbidity source addition means 6 has an addition port connected to a pipe on the upstream side of the membrane filtration means 1. Such a turbidity source addition means 6 adds a turbidity source to the raw water supplied to the membrane filtration means 1 in accordance with a command from the control means 4. As the turbidity source, it is preferable to use a substance that has a property of dissolving in water, such as calcium hypochlorite or bubbles of 1 mm or less, and disappears by dissolution in a predetermined time.

  The film break detection process of the present embodiment will be described. The control means 4 takes in the measured value A of turbidity from the treated water quality measuring means 3 when the membrane filtration apparatus is performing a basic operation.

  Next, when detecting the breakage of the filtration membrane, the control means 4 outputs a turbidity source addition command to the turbidity source addition means 6. The turbidity source addition means 6 adds a predetermined amount of the turbidity source to the raw water to be treated in accordance with the command from the control means 4. The amount added here may be determined in consideration of the dissolution rate of the turbidity source and the flow time from the addition position to the measurement position of the treated water quality measuring means 3. The flow-down time is a time measured in advance when the filter membrane is broken.

  After the turbidity source is added, the control means 4 takes in the measured value B of turbidity from the treated water quality measurement means 3. In addition, what is necessary is just to set so that the turbidity of the water quality by a turbidity source can be reflected in the measured value B about the time from the time of adding a turbidity source until acquisition of the measured value B. For example, the acquisition time of the measurement value B may be determined based on the length of the pipe from the addition position of the turbidity source to the measurement position of the treated water quality measurement means 3, the passing flow rate, and the like.

  Next, the control means 4 compares the measurement value A with the measurement value B, and detects the breakage of the filtration membrane based on the comparison result. More specifically, when the measured value B is larger than the measured value A, the control means 4 interprets that the turbidity source is leaking from the broken portion of the filtration membrane, and the filtration membrane is broken. Is determined. The processing after the determination is the same as that of Example 1-1. Further, the turbidity source contained in the filtered water disappears on the downstream side of the measurement position of the treated water quality measuring means 3. Note that when the measurement value B is equal to or less than the measurement value A, the control unit 4 determines that the filtration membrane is not broken.

  Calcium hypochlorite employed as a turbidity source in this example has a bactericidal action and a filter membrane cleaning action. In addition, since bubbles of 1 mm or less generate OH radicals when dissolved or crushed by pressure stimulation, the generated OH radicals exert a bactericidal action and a filter membrane cleaning action. Therefore, according to the present Example, in addition to the effect which can detect the fracture | rupture of a filtration membrane exactly, the disinfection effect of purified water and the cleaning effect of a filtration membrane can also be exhibited.

  As a conventional method for detecting breakage, there is a method of adding turbidity such as kaolin or silicon earth to raw water when measuring the turbidity of filtered water (for example, JP-A-6-320157). However, although this method is harmless for hygiene, it is not preferable because kaolin and silicon earth are mixed into the treated water. In this respect, according to the present embodiment, the turbidity source such as calcium hypozinc acid disappears after the elapse of a predetermined time, so that the degree of purification of the treated water in the subsequent stage is improved.

  In addition, the membrane breakage detection method using the membrane filtration apparatus of the present embodiment includes a filtration step for separating and removing turbidity contained in raw water with a filtration membrane, and a water quality for measuring the turbidity of filtered water that has passed through the filtration membrane. A measurement step and a membrane breakage detection step of detecting a breakage of the filtration membrane based on the measurement value of the water quality measurement step are provided. Then, the membrane breakage detection step adds a turbidity source to the raw water upstream of the membrane filtration means, and detects the breakage of the filtration membrane based on the measured value taken from the water quality measurement means after the addition of the turbidity source. .

(Example 2-2)
FIG. 7 is a diagram showing a second embodiment of the membrane filtration apparatus of the reference example to which the present invention is applied. The membrane filtration apparatus of the present embodiment is different from the embodiment 2-1 in that the membrane breakage detection process is started based on the measurement value of the water quality measurement means 5 to be treated installed on the upstream side of the membrane filtration means 1. The treated water quality measuring means 5 here is a turbidimeter that measures the turbidity of the raw water supplied to the membrane filtration means 1, and transmits the measured value to the control means 4.

  That is, as shown in FIG. 7, the membrane filtration apparatus of the present embodiment has the treated water quality measuring means 5 of FIG. 3 disposed in the membrane filtration treatment apparatus of FIG. This function is implemented in the control means 4. Therefore, according to the present embodiment, in addition to the effects described in Embodiment 2-1, when the raw water turbidity to be treated is relatively small, the treated water quality measuring means 5 can automatically detect. In other words, it is possible to automatically detect when the film break detection process should be started. As a result, the breakage of the filtration membrane can be accurately detected, and the usability of the apparatus is improved.

(Example 2-3)
FIG. 8 is a diagram showing a third embodiment of the membrane filtration apparatus of the reference example to which the present invention is applied. The membrane filtration processing apparatus of the present embodiment is different from that of Example 2-1 in that a plurality of the membrane filtration means 1 and the filtration flow rate changing means 2 of FIG. In the present embodiment, an example in which three membrane filtration means 1 and three filtration flow rate changing means 2 are arranged will be described, but the number may be increased as appropriate.

  As shown in FIG. 8, the membrane filtration means 1-1 to 1-3 are arranged in parallel. The filtration flow rate changing means 2-1 to 2-3 are provided on the upstream side of the membrane filtration means 1-1 to 1-3. For example, the filtration flow rate changing means 2-1 is provided in series upstream of the membrane filtration means 1-1. The treated water quality measuring means 3 measures the turbidity after joining the treated water flowing out from the membrane filtration means 1-1 to 1-3.

  The control means 4 applied to the membrane filtration processing apparatus of this embodiment takes in the measured value A of turbidity from the treated water quality measuring means 3 as the first measurement value when the membrane filtration processing apparatus is performing a basic operation. Next, when detecting the breakage of the filtration membrane, the control means 4 outputs a turbidity source addition command to the turbidity source addition means 6. The turbidity source addition means 6 adds a predetermined amount of the turbidity source to the raw water supplied to the membrane filtration means 1-1 according to the command of the control means 4. Next, the control unit 4 takes in the turbidity measurement value B <b> 1 from the treated water quality measurement unit 3. In addition, what is necessary is just to set so that the water quality after addition of a turbidity source can be reflected in measurement value B1 about the time from the time of adding a turbidity source until acquisition of measured value B1.

  And the control means 4 compares the measured value A and measured value B1, and when measured value B1 is larger than measured value A, it determines with the fracture | rupture having arisen in the filtration membrane of the membrane filtration means 1-1. When the measurement value B is equal to or less than the measurement value A, the control unit 4 determines that the filtration membrane of the membrane filtration unit 1-1 is not broken. Processing after the determination is the same as in the first embodiment. Although the example which detects the fracture | rupture of the filtration membrane of the membrane filtration means 1-1 was demonstrated typically, the case of the membrane filtration means 1-2 and 1-3 is also the same.

  When such a membrane breakage detection process is executed in order for each of the membrane filtration means 1-1 to 1-3, the membrane filtration means (for example, the membrane filtration means 1-1) in which the filtration membrane is broken can be specified. Therefore, according to the present embodiment, in addition to the effects described in the embodiment 2-1, even when the plurality of membrane filtration means 1-1 to 1-3 are disposed, the membrane filtration means to be stopped (for example, Since the membrane filtration means 1-1) can be accurately specified, safe and safe water supply can be facilitated.

(Example 2-4)
FIG. 9 is a diagram showing a fourth embodiment of the membrane filtration apparatus of the reference example to which the present invention is applied. The membrane filtration treatment apparatus of the present embodiment is the second embodiment in that the membrane breakage detection process is started based on the measurement value of the treated water quality measurement means 5 installed on the upstream side of the membrane filtration means 1-1 to 1-3. -3. The treated water quality measuring means 5 here is a turbidimeter that measures the turbidity of the raw water that is branched and supplied to the membrane filtration means 1-1 to 1-3, and transmits the measured value to the control means 4. .

  That is, as shown in FIG. 9, the membrane filtration apparatus of the present embodiment is provided with the treated water quality measuring means 5 of FIG. 5 in the membrane filtration treatment apparatus of FIG. 8, and controls the treated water quality measuring means 5. This function is implemented in the control means 4. Therefore, according to the present embodiment, in addition to the effects described in Embodiment 2-3, a case where the raw water turbidity to be treated is relatively small can be automatically detected by the treated water quality measuring means 5. In other words, it is possible to automatically detect when the film break detection process should be started. As a result, the breakage of the filtration membrane can be accurately detected, and the usability of the apparatus is improved.

As described above, according to the first embodiment and the reference example , the membrane filtration means 1 can be obtained by reducing the flow rate of the raw water passing through the filtration membrane or by adding a turbidity source to the raw water passing through the filtrate. It is possible to increase the turbidity of filtered water when the filter membrane breaks. Therefore, the membrane breakage detection sensitivity based on the turbidity measurement of the treated water quality measuring means 3 is improved. As a result, since the rupture of the filtration membrane can be accurately detected, the treatment for the rupture of the membrane can be accurately performed, so that safe and safe supply of purified water is facilitated.

It is a figure which shows the 1st Example of the membrane filtration processing apparatus of 1st embodiment to which this invention is applied. FIG. 2 is an example in which the change in the turbidity of filtered water relative to the amount of raw water passing through the filtration membrane of the membrane filtration means in FIG. 1 is measured. It is a figure which shows the 2nd Example of the membrane filtration processing apparatus of 1st embodiment to which this invention is applied. It is a figure which shows the 3rd Example of the membrane filtration processing apparatus of 1st embodiment to which this invention is applied. It is a figure which shows the 4th Example of the membrane filtration processing apparatus of 1st embodiment to which this invention is applied. It is a figure which shows the 1st Example of the membrane filtration processing apparatus of the reference example to which this invention is applied. It is a figure which shows the 2nd Example of the membrane filtration processing apparatus of the reference example to which this invention is applied. It is a figure which shows the 3rd Example of the membrane filtration processing apparatus of the reference example to which this invention is applied. It is a figure which shows the 4th Example of the membrane filtration processing apparatus of the reference example to which this invention is applied.

Explanation of symbols

1 membrane filtration means 2 filtration flow rate changing means 3 treated water quality measuring means 4 control means 5 treated water quality measuring means 6 turbidity source adding means

Claims (7)

Membrane filtration means having a filtration membrane for separating and removing turbidity contained in raw water, water quality measurement means for measuring the turbidity of filtrate water of the membrane filtration means, and based on the measured value of the water quality measurement means, A membrane rupture detecting means for detecting a rupture, and a filtration flow rate changing means for adjusting the flow rate of the raw water passing through the filtration membrane based on a command from the membrane rupture detection means ,
The membrane breakage detecting means outputs a command to reduce the passage flow rate to the filtration flow rate changing means to reduce the flow rate of the raw water passing through the filtration membrane, and the measurement taken from the water quality measurement means after the reduction of the passage flow rate A membrane filtration apparatus for detecting breakage of the filtration membrane based on a value. The membrane breakage detection means outputs a command to reduce the passage flow rate to the filtration flow rate change means, obtains the measurement value of the water quality measurement means before reducing the passage flow rate as a first measurement value, and passes the passage The measurement value of the water quality measuring means after reducing the flow rate is acquired as a second measurement value, and the filter membrane breaks when the second measurement value is larger than the first measurement value. The membrane filtration processing apparatus of Claim 1 determined to be a thing. The membrane breakage detecting means outputs a command to reduce the passage flow rate to the filtration flow rate changing means to obtain a measurement value of the water quality measurement means after reducing the passage flow rate, and the obtained measurement value is a set value. The membrane filtration processing apparatus according to claim 1, wherein it is determined that a breakage has occurred in the filtration membrane when larger than. The film breaking detecting means, according to any one of claims 1 to 3 outputs a command to return the amount of based on the flow rate through the filtration flow changing means when it is determined that there is no break in the filtration membrane Membrane filtration equipment. A treated water quality measuring means for measuring the turbidity of raw water upstream of the membrane filtration means is provided, and the membrane breakage detecting means is configured to change the filtration flow rate when the measured value of the treated water quality measuring means is equal to or less than a set value. The membrane filtration processing apparatus according to any one of claims 1 to 4 , wherein a command for decreasing the passage flow rate is output to the means to reduce the passage flow rate . A plurality of the membrane filtration means and the filtration flow rate changing means are provided, and the water quality measurement means measures the turbidity after merging of treated water flowing out from each of the membrane filtration means,
The membrane breakage detecting means outputs a command to reduce the passage flow rate to one of the filtration flow rate changing means among the plurality of filtration flow rate changing means to reduce the passage flow rate of the one membrane filtration means. The membrane filtration processing apparatus of any one of thru | or 5. The membrane breakage detection means outputs a command to increase the passage flow rate to the other filtration flow rate change means while reducing the passage flow rate of the one membrane filtration means, and determines the passage flow rate of the other membrane filtration means. The membrane filtration processing apparatus according to claim 6 to be increased.

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