JP2006007131A - Method for preventing filtering membrane part from clogging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preventing a filtering membrane from clogging by preventing materials suspended in water to be treated from depositing on the filtering membrane part without using chemicals and by removing the suspended materials deposited on the filtering membrane part. <P>SOLUTION: In this method for preventing the filtering membrane part 3 from clogging by blowing concentrated wastewater containing suspended materials, generated on the filtering membrane part 3 at specified intervals in the process of filtering the water to be treated, a circulating circuit 10 is constituted by connecting a water supply line 2a on the upstream side of the filtering membrane part 3, through a circulating line 9, with a concentrated wastewater containing suspended material line 6 connected to the filtering membrane part 3, and after the water supply line 2a on the upstream side of the filtering membrane part 3, a treated water line 2b on the downstream side of the filtering membrane part 3 and the line 6 of concentrated wastewater containing suspended materials are closed and the concentrated wastewater containing suspended materials is forcedly circulated in the circulating circuit 10 before blowing the concentrated wastewater containing suspended materials, the water supply line 2a on the upstream side of the filtering membrane part 3 and the concentrated wastewater containing suspended material line 6 are opened, and the concentrated wastewater containing suspended materials is blown. Thereby, the suspended materials deposited on the membrane surface of the filtering membrane part 3 are peeled off from the membrane surface by the flow of circulation water and the suspended materials peeled off are discharged from the concentrated wastewater containing suspended material line 6 together with the concentrated wastewater containing suspended materials. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for preventing clogging of a filtration membrane portion caused by adhering suspended substances in water to be treated to a filtration membrane portion that filters raw water (treated water) supplied by a pump.

  2. Description of the Related Art Conventionally, a process of filtering through a filtration membrane is known as a means for removing dissolved substances, suspended substances such as dust and dirt contained in raw water. As filtration membranes used in the filtration membrane portion, ultrafiltration membranes (UF membranes), microfiltration membranes (MF membranes), nanofiltration membranes (NF membranes), and reverse osmosis membranes (RO membranes) are generally known. These filtration membranes have different filtration functions. Among them, the filtration function of the ultrafiltration membrane is the lowest, and the filtration function of the reverse osmosis membrane is the highest. These filtration membranes can be used for treated water, for example, steam boilers, hot water boilers, cooling towers, water heaters and other thermal equipment, semiconductor manufacturing, electronic component washing, medical equipment washing, etc. It is selected and used accordingly.

  In the process of filtering the raw water by the filtration membrane part, suspended solid concentration wastewater is generated in the filtration membrane part, and this suspended matter concentrated wastewater is discharged from the suspended matter concentration drainage line. In the vicinity of the membrane part, the concentration of the suspended matter contained in the raw water becomes high, and contamination due to phenomena such as fouling and scaling occurs on the membrane surface of the filtration membrane part.

  Fouling is a phenomenon in which suspended solid components, colloidal components, organic components, etc. in raw water are deposited and adsorbed on the membrane surface. Scaling is the concentration of dissolved substances dissolved in raw water above the solubility. This refers to the phenomenon of precipitation and adhesion on the film surface.

  As described above, when fouling or scaling occurs on the membrane surface of the filtration membrane portion, the filtration membrane portion is clogged, and the treated water is increased due to an increase in membrane differential pressure and a decrease in the amount of permeate (flux). The situation of the fall of the recovery rate and the permeated water quality occurs.

Therefore, as a means for preventing clogging of the filtration membrane part due to suspended substances in the raw water, it is known that the filtration membrane part is prevented from being clogged by periodically injecting a chemical and washing the filtration membrane part. (See Patent Document 1).
Japanese Patent Laid-Open No. 5-220480

  However, according to the method for preventing clogging of the filtration membrane part, although the clogging of the filtration membrane part can be prevented, a part of the medicine is treated by the means for supplying the chemical and washing the filtration membrane part. There is a possibility of being taken into water, which may be an obstacle to the use of treated water. In addition, when the treated water is discharged after use, there is a problem that if it is discharged into sewage or the like as long as it is not subjected to a special treatment for removing the chemical, it may cause environmental pollution.

  As a means for solving such a problem, the present inventors prevent the suspended matter in the raw water from adhering to the filtration membrane part without using a chemical, and the suspended matter attached to the filtration membrane part. Research has been conducted on the removal, and it has been found that it can be solved by intermittently blowing the suspended solid concentration wastewater generated in the filtration membrane part at a predetermined interval in the process of filtering raw water, and filed earlier (Japanese Patent Application 2004). -97812).

  The object of the present invention is to more effectively prevent the suspension of raw water, that is, suspended matter in the water to be treated, from adhering to the filtration membrane without using any chemicals, and the suspended matter attached to the filtration membrane. It is an object of the present invention to provide a method for preventing clogging of a filtration membrane part by removing clogging more effectively.

  In order to achieve the above object, the filtration membrane portion clogging prevention method according to the first aspect of the present invention is the method for preventing suspended solid concentration wastewater generated in the filtration membrane portion in the process of filtering the water to be treated at predetermined intervals. A method for preventing clogging of the filtration membrane part by blowing, wherein a circulation circuit is formed by connecting a water supply line upstream of the filtration membrane part and a suspended solid concentration drainage line connected to the filtration membrane part by a circulation line. And before closing the suspended matter concentrated drainage, close the water supply line upstream of the filtration membrane part, the treated water line downstream of the filtration membrane part and the suspended substance concentrated drainage line, and the circulation circuit The suspension material concentrated waste water is forcibly circulated in the inside, and then the water supply line and the suspended material concentration drainage line on the upstream side of the filtration membrane portion are opened to blow the suspended material concentration wastewater.

  In this way, a circulation circuit is constructed by connecting the suspended water concentration drainage line connected to the filtration membrane section upstream of the water supply line and the filtration membrane section with the circulation line, and before the suspension material concentration drainage blow, When the water supply line upstream of the filtration membrane unit, the treated water line downstream of the filtration membrane unit and the suspended solid concentration drainage line are closed, and the suspended matter concentrated drainage is forcibly circulated in the circulation circuit, the filtration membrane unit Suspended substances adhering to the membrane surface are separated from the membrane surface by the flow rate of the circulating water. Thereafter, when the water supply line and the suspended solid concentration drainage line upstream of the filtration membrane part are opened and the suspended matter concentrated drainage is blown, the separated suspended substance is concentrated with the suspended substance concentrated wastewater. It can be discharged from the drainage line.

  Further, as described above, when the suspended matter adhering to the membrane surface of the filtration membrane part is peeled off from the membrane surface, the suspended matter concentrated drainage is circulated without supplying the water to be treated. Since the suspended substances adhering to the substrate are peeled off, the discharge amount of the water to be treated for blowing can be reduced, that is, the waste water can be saved, which is economical.

  According to a second aspect of the present invention, there is provided a method for preventing clogging of a filtration membrane portion. The blow is stopped when the value becomes constant.

  If it does in this way, useless discharge of the treated water for blow can be prevented, and the amount of discharged treated water can be reduced.

  According to a third aspect of the present invention, there is provided a method for preventing clogging of a filtration membrane portion, wherein the turbidity of a suspended solid-concentrated wastewater is detected immediately after the start of blowing the suspended solid-concentrated wastewater according to the first aspect, If the degree exceeds the specified value, change the interval of a series of operations to forcibly circulate the suspended solid concentrated wastewater and blow the suspended solid concentrated wastewater, and / or the time to blow the suspended solid concentrated wastewater. It is characterized by.

  In this way, immediately after the start of the suspension of concentrated suspended solids, by detecting the turbidity of the concentrated suspended wastewater, it is possible to know the degree of adhesion of suspended solids to the membrane surface of the filtration membrane part. By changing the interval of a series of operations and / or changing the time to blow the suspended solid concentrated wastewater by forcibly circulating the suspended solid concentrated wastewater and / or blowing the suspended solid concentrated wastewater. Thus, adhesion of the suspended substance to the membrane surface of the filtration membrane part is reduced as much as possible, and clogging of the filtration membrane part due to the suspended substance can be eliminated at an early stage.

  According to a fourth aspect of the present invention, there is provided a method for preventing clogging of a filtration membrane part according to the first aspect of the present invention, wherein the turbidity of the suspended matter concentrated drainage is detected immediately after the suspension material concentrated drainage blow starts. Depending on the degree, it is characterized in that the interval of a series of operations for forcibly circulating the suspended solid concentrated waste water and blowing the suspended solid concentrated waste water and / or the time for blowing the suspended solid concentrated waste water are changed.

  In this way, immediately after the start of the suspension of concentrated suspended solids, by detecting the turbidity of the concentrated suspended wastewater, it is possible to know the degree of adhesion of suspended solids to the membrane surface of the filtration membrane part. Depending on the degree, the filtration membrane section can be changed by changing the interval between the series of operations for forcibly circulating the suspended solid concentrated wastewater and blowing the suspended solid concentrated wastewater and / or the time for blowing the suspended solid concentrated wastewater. Suspended substances adhere to the membrane surface as much as possible, and clogging of the filtration membrane due to suspended substances can be eliminated at an early stage, and wasteful discharge of treated water for blowing can be prevented, The amount of water to be treated can be reduced.

  According to the present invention, the circulation line is formed by connecting the suspended water concentration drainage line connected to the filtration membrane section upstream of the water supply line and the filtration membrane section with the circulation line. In addition, the water supply line on the upstream side of the filtration membrane part, the treated water line on the downstream side of the filtration membrane part and the suspension material concentration drainage line are closed, and the suspension material concentration drainage is forcibly circulated in the circulation circuit. It can be peeled off from the membrane surface by the flow pressure of the suspended solid concentration drainage that circulates the suspended matter attached to the membrane surface of the membrane part. Thereafter, the water supply line and the suspended solid concentration drainage line on the upstream side of the filtration membrane part are opened, and the suspended suspended matter concentrated drainage is blown to suspend the separated suspended matter together with the suspended matter concentrated drainage. It can be discharged from the substance concentration drainage line. Thereby, the clogging of the filtration membrane part due to the suspended substance can be eliminated at an early stage.

  Further, as described above, when the suspended matter adhering to the membrane surface of the filtration membrane part is peeled off from the membrane surface, the suspended matter concentrated drainage is circulated without supplying the water to be treated. Since the suspended substances adhering to the surface are peeled off, the discharge amount of the water to be treated for blowing can be reduced, that is, the waste water can be saved, which is economical.

  Hereinafter, the best mode for carrying out the clogging prevention method for the filtration membrane portion according to the present invention will be described.

(Embodiment 1)
The filtration membrane part clogging prevention method of this example prevents the filtration membrane part from being clogged by blowing the suspended matter concentrated waste water generated in the filtration membrane part at a predetermined interval in the process of filtering the water to be treated. In this method, a water supply line upstream of the filtration membrane section and a suspended substance concentration drainage line connected to the filtration membrane section are connected by a circulation line to form a circulation circuit, and the suspension substance concentration drainage blow is performed. Before closing the water supply line upstream of the filtration membrane section, the treated water line downstream of the filtration membrane section and the suspended solid concentration drainage line, and forcibly circulating the suspended solid concentration drainage in the circulation circuit The water supply line and the suspended solid concentration drainage line on the upstream side of the filtration membrane part were opened to blow the suspended matter concentrated drainage.

  The flow rate and time for forcibly circulating the suspended matter concentrated wastewater in the circulation circuit is the dynamic pressure required to peel off the suspended matter concentrated wastewater circulating the suspended matter attached to the membrane surface of the filtration membrane part. It is set based on the flow rate obtained and the time required for peeling.

  Also, during the time when the suspended matter concentrated wastewater is blown, the turbidity of the suspended matter concentrated wastewater that has become higher due to the suspended matter peeled off from the membrane surface of the filtration membrane portion is lowered by the blow. It is set based on the time required. Here, the turbidity of the suspended solid concentration drainage that has become higher due to the suspended substance peeled off from the membrane surface of the filtration membrane section is lowered by the blow. The suspended matter discharged from the suspended matter concentrated drainage line by the blow A state in which the turbidity of concentrated wastewater is constant.

  In addition, the interval between the series of operations in which the suspended matter concentrated wastewater is forced to circulate in the circulation circuit and the suspended matter concentrated wastewater is blown is set so that the suspended matter in the suspended material concentrated wastewater adheres to the membrane surface of the filtration membrane section. It is set on the basis of the time when there is a risk of clogging.

  In this way, a circulation circuit is constructed by connecting the suspended water concentration drainage line connected to the filtration membrane section upstream of the water supply line and the filtration membrane section with the circulation line, and before the suspension material concentration drainage blow, The water supply line upstream of the filtration membrane part, the treated water line downstream of the filtration membrane part and the suspended solid concentration drainage line are closed, and the suspended substance concentrated drainage is set in the circulation circuit with a set flow rate. When forced circulation is performed, the suspended matter adhering to the membrane surface of the filtration membrane part is peeled off from the membrane surface by the flow rate of the circulating water. After that, when the water supply line and the suspended solid concentration drainage line on the upstream side of the filtration membrane part are opened and the suspended matter concentrated drainage is blown for a set time, the separated suspended substance is combined with the suspended matter concentrated drainage. It can be discharged from the suspended solids drainage line.

  Then, by performing a series of operations for forcibly circulating the suspended matter-concentrated wastewater and blowing the suspended matter-concentrated wastewater at a set interval, clogging of the filtration membrane portion due to the suspended matter can be eliminated at an early stage. It will be possible. Further, as described above, when the suspended matter adhering to the membrane surface of the filtration membrane part is peeled off from the membrane surface, the suspended matter concentrated drainage is circulated without supplying the water to be treated. Since the suspended substances adhering to the surface are peeled off, the discharge amount of the water to be treated for blowing can be reduced, that is, the waste water can be saved, which is economical.

(Embodiment 2)
The filtration membrane part clogging prevention method of this example prevents the filtration membrane part from being clogged by blowing the suspended matter concentrated waste water generated in the filtration membrane part at a predetermined interval in the process of filtering the water to be treated. In this method, a water supply line upstream of the filtration membrane section and a suspended substance concentration drainage line connected to the filtration membrane section are connected by a circulation line to form a circulation circuit, and the suspension substance concentration drainage blow is performed. Before closing the water supply line upstream of the filtration membrane section, the treated water line downstream of the filtration membrane section and the suspended solid concentration drainage line, and forcibly circulating the suspended solid concentration drainage in the circulation circuit Then, the water supply line and the suspended matter concentration drainage line on the upstream side of the filtration membrane part are opened, and the suspended matter concentration drainage is blown. The suspending substance-concentrated waste water is blown by observing the turbidity of the suspended substance-concentrating waste water at the time of blowing, and stopping the blowing when the turbidity becomes constant.

  In this example, the flow rate and time for forcibly circulating the suspended solid concentrated wastewater in the circulation circuit are set in the same manner as in the first embodiment. In addition, the interval of a series of operations for forcibly circulating the suspended matter concentrated wastewater and blowing the suspended matter concentrated wastewater in the circulation circuit is set in the same manner as in the first embodiment.

  In this way, a circulation circuit is constructed by connecting the suspended water concentration drainage line connected to the filtration membrane section upstream of the water supply line and the filtration membrane section with the circulation line, and before the suspension material concentration drainage blow, The water supply line upstream of the filtration membrane part, the treated water line downstream of the filtration membrane part and the suspended solid concentration drainage line are closed, and the suspended substance concentrated drainage is set in the circulation circuit with a set flow rate. When forced circulation is performed, the suspended matter adhering to the membrane surface of the filtration membrane part is peeled off from the membrane surface by the flow rate of the circulating water.

  Thereafter, when the water supply line and the suspended solid concentration drainage line upstream of the filtration membrane part are opened and the suspended matter concentrated drainage is blown, the separated suspended substance is concentrated with the suspended substance concentrated wastewater. It can be discharged from the drainage line. Then, by performing a series of operations for forcibly circulating the suspended matter-concentrated wastewater and blowing the suspended matter-concentrated wastewater at a set interval, clogging of the filtration membrane portion due to the suspended matter can be eliminated at an early stage. It will be possible.

  Further, as described above, when the suspended matter adhering to the membrane surface of the filtration membrane part is peeled off from the membrane surface, the suspended matter concentrated drainage is circulated without supplying the water to be treated. Since the suspended substances adhering to the surface are peeled off, the discharge amount of the water to be treated for blowing can be reduced, that is, the waste water can be saved, which is economical.

  Furthermore, in this example, the turbidity of the suspended solid concentration drainage was observed when the suspended solid concentration drainage was blown, and the blow was stopped when the turbidity became constant. Unnecessary discharge of the water to be treated can be prevented, and the discharge amount of the water to be treated can be further reduced.

(Embodiment 3)
The filtration membrane part clogging prevention method of this example prevents the filtration membrane part from being clogged by blowing the suspended matter concentrated waste water generated in the filtration membrane part at a predetermined interval in the process of filtering the water to be treated. In this method, a water supply line upstream of the filtration membrane section and a suspended substance concentration drainage line connected to the filtration membrane section are connected by a circulation line to form a circulation circuit, and the suspension substance concentration drainage blow is performed. Before closing the water supply line upstream of the filtration membrane section, the treated water line downstream of the filtration membrane section and the suspended solid concentration drainage line, and forcibly circulating the suspended solid concentration drainage in the circulation circuit Then, the water supply line and the suspended matter concentration drainage line on the upstream side of the filtration membrane part are opened, and the suspended matter concentration drainage is blown. Then, immediately after the start of the blow of the suspended solid concentrated wastewater, the turbidity of the suspended solid concentrated wastewater is detected, and when the turbidity exceeds a predetermined value, the suspended suspended solid concentrated wastewater is forcedly circulated. The interval between a series of operations for blowing concentrated wastewater and the time for blowing suspended solids wastewater were changed.

  In this example, the flow rate and time for forcibly circulating the suspended solid concentrated wastewater in the circulation circuit are set in the same manner as in the first embodiment. Further, the time during which the suspended solid concentrated waste water is blown is set as the basic time in the same manner as in the first embodiment. Further, the interval between a series of operations for forcibly circulating the suspended matter concentrated wastewater and blowing the suspended matter concentrated wastewater in the circulation circuit is set as a basic interval in the same manner as in the first embodiment.

  Further, in this example, when the turbidity of the suspended matter concentrated wastewater exceeds a predetermined value, a series of operation intervals for forcibly circulating the suspended matter concentrated wastewater and blowing the suspended matter concentrated wastewater in the circulation circuit. In addition, the time during which the suspended solid concentration drainage is blown is separately set as a correction interval and a correction time. The correction interval and the correction time are set on the basis of the interval and time at which the turbidity exceeds a predetermined value and the turbidity of the suspended matter-concentrated waste water is constant by blowing, and is set as a reference. The interval of a series of operations for forcibly circulating suspended matter concentrated wastewater and blowing suspended matter concentrated wastewater is set to be shorter than the basic interval, and the open / close valve and blow valve open time is longer than the basic time. Is set as

  Then, as described above, immediately after the suspension material concentrated drainage blow is started, when the turbidity of the suspended material concentrated wastewater is detected and the turbidity of the suspended material concentrated wastewater exceeds a predetermined value, Change the basic interval of the series of operations to forcibly circulate suspended solid concentrated wastewater and blow suspended solid concentrated wastewater to the corrected interval, and change the basic time to blow suspended solid concentrated wastewater to the corrected time It is supposed to be.

  In addition, the basic interval of a series of operations for forcibly circulating the suspended solid concentrated wastewater and blowing the suspended solid concentrated wastewater in the circulation circuit is set as the correction interval, and the basic time during which the suspended solid concentrated wastewater is blown. The predetermined value of the turbidity of the suspended solid-concentrated waste water, which serves as an index for changing the value to the correction time, is set as follows.

  The specified turbidity value of suspended solids drainage is forced to suspend suspended solids in the circulation circuit when the turbidity of suspended solids drainage immediately after the start of blown suspension of concentrated suspended solids exceeds that value. In the basic interval of a series of operations to circulate and blow suspended suspended matter concentrated wastewater and the basic time to blow suspended suspended matter concentrated wastewater, the suspended suspended matter concentrated wastewater discharged from the suspended suspended matter concentrated drainage line is blown. It is set as a value at which the blow ends before the turbidity becomes constant.

  In this way, a circulation circuit is constructed by connecting the suspended water concentration drainage line connected to the filtration membrane section upstream of the water supply line and the filtration membrane section with the circulation line, and before the suspension material concentration drainage blow, The water supply line upstream of the filtration membrane part, the treated water line downstream of the filtration membrane part and the suspended solid concentration drainage line are closed, and the suspended substance concentrated drainage is set in the circulation circuit with a set flow rate. When forced circulation is performed, the suspended matter adhering to the membrane surface of the filtration membrane part is peeled off from the membrane surface by the flow rate of the circulating water. Thereafter, when the water supply line and the suspended solid concentration drainage line upstream of the filtration membrane section are opened and the suspended solid concentration drainage is blown for the set basic time, the separated suspended substance is suspended in the suspended solid concentration drainage. At the same time, it can be discharged from the suspended solid concentration drainage line.

  Then, the clogging of the filtration membrane due to the suspended solids can be eliminated at an early stage by performing a series of operations for forcibly circulating the suspended solid concentrated wastewater and blowing the suspended solid concentrated wastewater at a set basic interval. Will be able to.

  Furthermore, in this example, immediately after the start of the blowing of the suspended matter-concentrated wastewater, the degree of adhesion of the suspended matter to the membrane surface of the filtration membrane portion can be known by detecting the turbidity of the suspended matter-concentrated wastewater. . When the turbidity exceeds a predetermined value, the basic interval of a series of operations for forcibly circulating the suspended solid concentrated wastewater and blowing the suspended solid concentrated wastewater is set to the correction interval and the suspended solid concentrated wastewater is blown. By changing the basic time to the correction time, adhesion of suspended substances to the membrane surface of the filtration membrane part will be reduced as much as possible, and clogging of the filtration membrane part due to suspended substances can be eliminated early. Become.

  Further, as described above, when the suspended matter adhering to the membrane surface of the filtration membrane part is peeled off from the membrane surface, the suspended matter concentrated drainage is circulated without supplying the water to be treated. Since the suspended substances adhering to the surface are peeled off, the discharge amount of the water to be treated for blowing can be reduced, that is, the waste water can be saved, which is economical.

  In this example, if the turbidity of the suspended solid concentrated drainage immediately after the start of blowing exceeds a predetermined value, the basics of a series of operations for forcibly circulating the suspended suspended solid concentrated wastewater and blowing the suspended solid concentrated wastewater The basic time for blowing the suspended matter concentrated wastewater is changed by changing the interval and the basic time for blowing the suspended matter concentrated wastewater. It is also possible to change only one of the basic times for blowing.

(Embodiment 4)
The filtration membrane part clogging prevention method of this example prevents the filtration membrane part from being clogged by blowing the suspended matter concentrated waste water generated in the filtration membrane part at a predetermined interval in the process of filtering the water to be treated. In this method, a water supply line upstream of the filtration membrane section and a suspended substance concentration drainage line connected to the filtration membrane section are connected by a circulation line to form a circulation circuit, and the suspension substance concentration drainage blow is performed. Before closing the water supply line upstream of the filtration membrane section, the treated water line downstream of the filtration membrane section and the suspended solid concentration drainage line, and forcibly circulating the suspended solid concentration drainage in the circulation circuit Then, the water supply line and the suspended matter concentration drainage line on the upstream side of the filtration membrane part are opened, and the suspended matter concentration drainage is blown. Immediately after the start of the blowing of the suspended solid concentration wastewater, the turbidity of the suspended solid concentration wastewater is detected, and the next suspended solid concentration wastewater is forcibly circulated according to the turbidity to blow the suspended solid concentration wastewater. The interval between a series of operations to be performed and the time for blowing the suspended matter concentrated waste water were changed.

  In this example, the flow rate and time for forcibly circulating the suspended solid concentrated wastewater in the circulation circuit are set in the same manner as in the first embodiment.

  In addition, the time during which the suspended matter concentrated wastewater is blown is set as the basic time in the same manner as in the first embodiment, and the turbidity of the suspended matter concentrated wastewater is lowered and becomes constant by blowing. Is set as a corresponding time according to the turbidity of the suspended solid concentration drainage immediately after the start of blowing.

  Further, the interval of a series of operations for forcibly circulating the suspended matter concentrated wastewater in the circulation circuit and blowing the suspended matter concentrated wastewater is set as a basic interval in the same manner as in the first embodiment, Based on the time when suspended substances in the substance-concentrated wastewater adhere to the membrane surface of the filtration membrane part and become clogged, the interval is set according to the turbidity of the suspended substance-concentrated wastewater immediately after the start of blowing. .

  Then, as described above, immediately after the suspension material concentrated drainage blow is started, the turbidity of the suspension material concentrated wastewater is detected, and the next suspended material concentrated wastewater is forcibly circulated to blow the suspended material concentrated wastewater. The suspension interval concentrated wastewater is blown by forcibly circulating the suspended matter concentration wastewater that is set according to the turbidity of the suspended matter concentration wastewater immediately after the start of the blow. The corresponding interval of the series of operations and the corresponding time for blowing the suspended solid concentrated drainage are changed.

  In this way, a circulation circuit is constructed by connecting the suspended water concentration drainage line connected to the filtration membrane section upstream of the water supply line and the filtration membrane section with the circulation line, and before the suspension material concentration drainage blow, The water supply line upstream of the filtration membrane part, the treated water line downstream of the filtration membrane part and the suspended solid concentration drainage line are closed, and the suspended substance concentrated drainage is set in the circulation circuit with a set flow rate. When forced circulation is performed, the suspended matter adhering to the membrane surface of the filtration membrane part is peeled off from the membrane surface by the flow rate of the circulating water. Thereafter, when the water supply line and the suspended solid concentration drainage line upstream of the filtration membrane section are opened and the suspended solid concentration drainage is blown for the set basic time, the separated suspended substance is suspended in the suspended solid concentration drainage. At the same time, it can be discharged from the suspended solid concentration drainage line.

  Then, by performing a series of operations for forcibly circulating the suspended matter-concentrated wastewater and blowing the suspended matter-concentrated wastewater at a set interval, clogging of the filtration membrane portion due to the suspended matter can be eliminated at an early stage. It will be possible.

  Furthermore, in this example, immediately after the start of the blowing of the suspended matter-concentrated wastewater, the degree of adhesion of the suspended matter to the membrane surface of the filtration membrane portion can be known by detecting the turbidity of the suspended matter-concentrated wastewater. . And according to the turbidity, the interval of a series of operation to forcibly circulate the suspended solid concentrated wastewater and blow the suspended solid concentrated wastewater to the corresponding interval, and the time to blow the suspended solid concentrated wastewater By changing the time, the adhesion of suspended substances to the membrane surface of the filtration membrane part is reduced as much as possible. Unnecessary discharge of treated water can be prevented, and the amount of treated water discharged can be reduced.

  In this example, according to the turbidity of the suspended solid concentrated drainage immediately after the start of blowing, the interval of a series of operations for forcibly circulating the suspended solid concentrated wastewater and blowing the suspended solid concentrated wastewater is taken as the corresponding interval, and The time to blow the suspended matter concentrated wastewater is set as the corresponding time, the interval of a series of operations for forcibly circulating the suspended matter concentrated wastewater and blowing the suspended matter concentrated wastewater, and the time to blow the suspended matter concentrated wastewater, Depending on the turbidity of the suspended solid concentrated wastewater immediately after the start of blowing, the corresponding interval of a series of operations for forcibly circulating the suspended solid concentrated wastewater and blowing the suspended solid concentrated wastewater and the corresponding time to blow the suspended solid concentrated wastewater However, it is either the interval of a series of operations to forcibly circulate suspended matter concentrated wastewater and blow suspended material concentrated wastewater, or the time to blow suspended material concentrated wastewater. Set may only change only one said.

  Next, a specific embodiment of the present invention will be described in detail with reference to the drawings.

(First example)
This example is an example of Embodiment 1, and FIG. 1 is a schematic explanatory diagram of a water treatment system that implements the clogging prevention method for the filtration membrane portion of this example. The water treatment system shown in FIG. 1 passes through a filtration membrane unit 3 for filtering suspended substances present in the treated water and a filtration membrane unit 3 through a water supply line 2 that feeds the treated water from the raw water tank 1. The storage tank 4 which stores the treated water obtained by this is arrange | positioned. Further, on the upstream side of the filtration membrane unit 3, a pump 5 is disposed that pressurizes and supplies treated water to the filtration membrane unit 3. The pump 5 also has a role of forcibly circulating the suspended matter concentrated wastewater generated in the filtration membrane section 3 in a circulation circuit described later.

  The filtration membrane unit 3 is connected to a suspension material concentration drainage line 6 for draining the suspension material concentration drainage generated in the filtration membrane unit 3 in the process of filtering the water to be treated by the filtration membrane unit 3. A blow line 7 and a drain line 8 are branched and connected to the suspended solid concentration drain line 6. Further, a circulation line 10 is configured by connecting a water supply line 2 a upstream of the pump 5 and a blow line 7 of the suspended solid concentration drainage line 6 connected to the filtration membrane unit 3 by a circulation line 9. An on-off valve 11 is disposed upstream of the water supply line 2a to which one end of the circulation line 9 is connected, and an on-off valve 12 is also provided on the treated water line 2b through which treated water treated by the filtration membrane unit 3 flows. Further, a blow valve 13 is arranged downstream of the blow line 7 to which the other end of the circulation line 9 is connected. A drain valve 14 is disposed in the drain line 8.

  In addition, the water treatment system is disposed on the on-off valve 11 disposed on the upstream side of the water supply line 2a to which the circulation line 9 is connected, and on the treated water line 2b for flowing treated water treated by the filtration membrane unit 3. An on-off command signal is output to the on-off valve 12, the blow valve 13 disposed on the downstream side of the blow line 7 to which the circulation line 9 is connected, and the drain valve 14 disposed on the drain line 8. Is provided with a control unit 16 that outputs a drive command signal for driving the pump 5 via an inverter 15 that varies the output frequency according to the output frequency.

  The control unit 16 includes an opening / closing valve 11 disposed in the water supply line 2a, an opening / closing valve 12 disposed in the treated water line 2b, a blow valve 13 disposed in the blow line 7, and a drain line 8 at predetermined intervals. A closed command signal for closing the drain valve 14 arranged for a predetermined time is output, and a drive command signal for driving the pump 5 at a predetermined rotation speed for a predetermined time is output. After the predetermined time has elapsed, the on-off valve 11 and the blow valve 14 are blown. An opening command signal for opening the valve 13 for a predetermined time is output, and an opening command signal for opening the on-off valve 12 and the drain valve 14 and a closing command signal for closing the blow valve 13 are output after the predetermined time during which the blow valve 13 is opened. In addition, a program for outputting a drive command signal for driving the pump 5 at a normal rotation speed in the filtration processing operation is provided.

  In addition, the control unit 16 collects a series of operations based on the series of signals at a predetermined interval, and during the operation, the on-off valve 11, the on-off valve 12, the blow valve 13, and the drainage are performed. A storage unit is provided for storing the time during which the valve 14 is closed, the time during which the pump 5 is driven at a predetermined rotational speed, the time during which the on-off valve 11 and the blow valve 13 are opened, the rotational speed of the pump 5 and the like. ing.

  Suspended substances in the concentrated suspended wastewater generated in the filtration membrane section 3 during the filtration treatment operation during the time when the series of actions based on the series of signals are collectively performed at predetermined intervals. Is set on the basis of the time during which there is a risk of clogging due to adhering to the membrane surface of the filtration membrane portion 3.

  Further, during the time when the on-off valve 11, on-off valve 12, blow valve 13 and drain valve 14 are closed during the above operation, suspended substances adhering to the membrane surface of the filtration membrane unit 3 will be described later. However, it is set on the basis of the time required for separation by the circulating suspended solid concentration drainage.

  Further, the rotational speed of the pump 5 when forcedly circulating the suspended matter-concentrated wastewater in the circulation circuit 10 is such that the suspended matter adhering to the membrane surface of the filtration membrane part 3 is separated by the circulating water described later. It is set on the basis of the number of rotations at which the flow rate at which a necessary dynamic pressure can be obtained.

  In addition, the time during which the on-off valve 11 and the blow valve 13 are open (the time during which the suspended solid concentration drainage is blown) is higher due to the suspended material peeled off from the membrane surface of the filtration membrane portion 3. It is set on the basis of the time required for the turbidity of the suspended suspended matter concentrated wastewater to be lowered by blowing. Here, the fact that the turbidity of the suspended solid concentration drainage that has become higher due to the suspended matter peeled off from the membrane surface of the filtration membrane portion is lowered by the blow, the suspension discharged from the suspended matter concentrated drainage line 6 by the blow This refers to the state where the turbidity of substance-concentrated wastewater is constant.

  With the water treatment system configured as described above, the method for preventing clogging of the filtration membrane portion according to the present invention is performed as follows.

  In the operation of the water treatment system, the water to be treated is supplied from the raw water tank 1 to the filtration membrane unit 3 through the water supply line 2 by driving the pump 5, and the treated water filtered by the filtration membrane unit 3 is stored in the storage tank 4. To be done.

  Then, when the set time for the filtration treatment operation has elapsed, the control unit 16 opens and closes the on-off valve 11 arranged on the water supply line 2a, the on-off valve 12 arranged on the treated water line 2b, and the blow arranged on the blow line 7. The closing command signal for closing the drain valve 14 disposed in the valve 13 and the drain line 8 for a set time and the driving command signal for driving the pump 5 at a predetermined number of revolutions are output. The on-off valve 12, the blow valve 13 and the drain valve 14 are closed for a set time to constitute the circulation circuit 10, and the pump 5 is driven at a predetermined rotational speed. As a result, the suspended solid concentrated wastewater generated in the filtration membrane unit 3 circulates in the circulation circuit 10. In this way, by forcibly circulating the suspended matter-concentrated wastewater in the circulation circuit 10, the suspended matter adhering to the membrane surface of the filtration membrane unit 3 is peeled off from the membrane surface by the flow rate of the circulating water.

  When the set time elapses, the control unit 16 outputs an opening command signal for opening the on-off valve 11 and the blow valve 13 for the set time, and the on-off valve 11 and the blow valve 13 are opened in response to the signal. As a result, the suspended solid-concentrated waste water circulated in the circulation circuit 10 is blown from the blow line 7 so as to be pushed out by the treated water supplied from the raw water tank 1. By thus suspending the suspended matter concentrated waste water, the suspended material peeled off from the membrane surface of the filtration membrane section 3 is discharged from the blow line 7 together with the suspended material concentrated waste water.

  When a set time for opening the on-off valve 11 and the blow valve 13 has elapsed, the control unit 16 outputs an open command signal for opening the on-off valve 12 and the drain valve 14 and a close command signal for closing the blow valve 13, A drive command signal for driving the pump 5 at a normal rotational speed is output. Upon receipt of such a signal, the on-off valve 12 and the drain valve 14 are opened, the blow valve 13 is closed, and the pump 5 is operated at a normal rotational speed. Drive, thereby returning to the filtration operation. And the said operation | movement is repeated for every set space | interval (time).

  As described above, the circulation circuit 10 is configured, and the suspension material concentrated waste water is forcibly circulated in the circulation circuit 10, so that the suspended material adhering to the membrane surface of the filtration membrane unit 3 is caused by the flow rate of the circulation water. It can be easily and more reliably peeled from the film surface. Thereafter, the separated suspended substance can be discharged from the suspended substance concentrated drainage line 6 together with the suspended substance concentrated drainage by blowing the suspended substance concentrated drainage. It is possible to eliminate clogging at an early stage.

  Further, as described above, when the suspended matter adhering to the membrane surface of the filtration membrane part 3 is peeled from the membrane surface, the membrane is obtained by circulating the suspended matter-concentrated waste water without supplying the water to be treated. Since the suspended matter adhering to the surface is peeled off, the discharge amount of the water to be treated for blowing can be reduced, that is, the waste water can be saved, which is economical.

(Second example)
This example is an example of Embodiment 2, and FIG. 2 is a schematic explanatory diagram of a water treatment system that implements the method for preventing clogging of the filtration membrane portion of this example. In the water treatment system shown in FIG. 2, the same components as those in FIG. 1 showing the first example which is an example of the first embodiment will be described with the same reference numerals. In this example, a turbidity meter 17 for detecting the turbidity of the suspended solid concentration drainage flowing through the blow line 7 is attached to the blow line 7 of the suspended solid concentration drainage line 6. The same as the first example shown in FIG. The turbidity meter 17 detects the turbidity of the suspended solid concentration drainage flowing through the blow line 7 and outputs the turbidity to the control unit 16.

  Further, in the control unit 16, as in the first example, an open / close command signal is output to the open / close valve 11, the open / close valve 12, the blow valve 13 and the drain valve 14, and the rotation speed of the pump 5 is set to the output frequency. A drive command signal for driving the pump 5 is output via an inverter 15 that is variable according to the above.

  As in the first example, the control unit 16 outputs a close command signal for closing the on-off valve 11, the on-off valve 12, the blow valve 13 and the drain valve 14 for a predetermined time at predetermined intervals, and the pump 5 is turned on. There is provided a program for outputting a drive command signal for driving for a predetermined time at a predetermined rotational speed, and outputting an open command signal for opening the on-off valve 11 and the blow valve 13 after the predetermined time has elapsed.

  Further, in this example, when the turbidimeter 17 detects that the turbidity of the suspended solid concentration drainage flowing through the blow line 7 becomes constant by opening the on-off valve 11 and the blow valve 13, the on-off valve 12 And a program for outputting an opening command signal for opening the drain valve 14 and a closing command signal for closing the blow valve 13 and outputting a driving command signal for driving the pump 5 at a normal rotational speed.

  Similarly to the first example, the control unit 16 collects a series of operations based on the series of signals and performs the operation at predetermined intervals. 12, a storage unit is provided for storing the time during which the blow valve 13 and the drain valve 14 are closed, the time during which the pump 5 is driven at a predetermined rotational speed, the rotational speed of the pump 5, and the like.

  A time period in which a series of operations based on the series of signals are collectively performed at predetermined intervals, and a time period during which the on-off valve 11, the on-off valve 12, the blow valve 13 and the drain valve 14 are closed in the operation. Further, the rotational speed of the pump 5 when the suspended substance concentrated waste water is forcibly circulated in the circulation circuit 10 is set in the same manner as in the first example.

  With the water treatment system configured as described above, the method for preventing clogging of the filtration membrane portion according to the present invention is performed as follows.

  The operation of the water treatment system is similar to the first example, in which treated water is supplied from the raw water tank 1 to the filtration membrane unit 3 through the water supply line 2 by driving the pump 5, and treated water filtered by the filtration membrane unit 3 is supplied. It is performed so as to be stored in the storage tank 4. Then, when the set time for the filtration treatment operation has elapsed, the control unit 16 opens and closes the on-off valve 11 arranged on the water supply line 2a, the on-off valve 12 arranged on the treated water line 2b, and the blow arranged on the blow line 7. The closing command signal for closing the drain valve 14 disposed in the valve 13 and the drain line 8 for a set time and the driving command signal for driving the pump 5 at a predetermined number of revolutions are output. The on-off valve 12, the blow valve 13 and the drain valve 14 are closed for a set time to constitute the circulation circuit 10, and the pump 5 is driven at a predetermined rotational speed. As a result, the suspended solid concentrated wastewater generated in the filtration membrane unit 3 circulates in the circulation circuit 10. In this way, by forcibly circulating the suspended matter-concentrated wastewater in the circulation circuit 10, the suspended matter adhering to the membrane surface of the filtration membrane unit 3 is peeled off from the membrane surface by the flow rate of the circulating water.

  When the set time elapses, the control unit 16 outputs an opening command signal for opening the on-off valve 11 and the blow valve 13 for the set time, and the on-off valve 11 and the blow valve 13 are opened in response to the signal. As a result, the suspended solid-concentrated waste water circulated in the circulation circuit 10 is blown from the blow line 7 so as to be pushed out by the treated water supplied from the raw water tank 1. By thus suspending the suspended matter concentrated waste water, the suspended material peeled off from the membrane surface of the filtration membrane section 3 is discharged from the blow line 7 together with the suspended material concentrated waste water.

  When the turbidimeter 17 detects that the turbidity of the suspended solid-concentrated waste water flowing through the blow line 7 is constant by opening the on-off valve 11 and the blow valve 13, the control unit 16 detects the on-off valve 12 and the waste water. An open command signal for opening the valve 14 and a close command signal for closing the blow valve 13 are output, and a drive command signal for driving the pump 5 at a normal rotational speed is output. While the valve 14 is opened and the blow valve 13 is closed, the pump 5 is driven at a normal rotational speed, thereby returning to the filtration processing operation. And the said operation | movement is repeated for every set space | interval (time).

  As described above, the circulation circuit 10 is configured, and the suspension material concentrated waste water is forcibly circulated in the circulation circuit 10, so that the suspended material adhering to the membrane surface of the filtration membrane unit 3 is caused by the flow rate of the circulation water. It can be easily and more reliably peeled from the film surface. Thereafter, the separated suspended substance can be discharged from the suspended substance concentrated drainage line 6 together with the suspended substance concentrated drainage by blowing the suspended substance concentrated drainage. The clogging of 3 can be eliminated at an early stage.

  Further, as described above, when the suspended matter adhering to the membrane surface of the filtration membrane part 3 is peeled from the membrane surface, the membrane is obtained by circulating the suspended matter-concentrated waste water without supplying the water to be treated. Since the suspended matter adhering to the surface is peeled off, the discharge amount of the water to be treated for blowing can be reduced, that is, the waste water can be saved, which is economical.

  Furthermore, in the blow of the suspended solid concentration drainage, the blow is stopped when the turbidimeter 17 detects that the turbidity of the suspended solid concentration drainage flowing through the blow line 7 becomes constant during the blow. Since it was made to do so, useless discharge | emission of the to-be-processed water for blows can be prevented, and the discharge amount of to-be-processed water can be further reduced.

(Third example)
This example is an example of the third embodiment. Since the water treatment system of this example is the same as that of the said 2nd example shown in FIG. 2 except the program of the control part 16, and the memory | storage information of a memory | storage part, FIG. 2 is used and this example is demonstrated.

  In this example, as in the first example, the control unit 16 outputs an open / close command signal to the open / close valve 11, the open / close valve 12, the blow valve 13 and the drain valve 14, and sets the rotation speed of the pump 5 to the output frequency. A drive command signal for driving the pump 5 is output via an inverter 15 that is varied accordingly.

  And the control part 16 is arrange | positioned at the on-off valve 11 arrange | positioned at the water supply line 2a, the on-off valve 12 arrange | positioned at the treated water line 2b, and the blow line 7 for every predetermined | prescribed basic space | interval like the 1st example. In addition to outputting a closing command signal for closing the blow valve 13 and the drain valve 14 disposed in the drain line 8 for a predetermined basic time, a drive command signal for driving the pump 5 at a predetermined rotation time for a predetermined basic time is output. After the predetermined basic time has elapsed, an opening command signal for opening the opening / closing valve 11 and the blow valve 13 for a predetermined basic time is output, and after the predetermined basic time for opening the blow valve 13 has elapsed, the opening / closing valve 12 and drainage A program for outputting an opening command signal for opening the valve 14 and a closing command signal for closing the blow valve 13 and outputting a drive command signal for driving the pump 5 at a normal rotational speed is provided.

  Furthermore, in this example, the turbidimeter 17 detects the turbidity of the suspended solid concentrated drainage immediately after the start of the blow of the suspended solid concentrated drainage flowing through the blow line 7 by opening the on-off valve 11 and the blow valve 13. When the degree exceeds a predetermined value, a series of operations based on the series of signals coming next is collectively changed, a predetermined basic interval for performing the operations, and a basic time for opening the on-off valve 11 and the blow valve 13 are changed. And a program for outputting a signal for instructing the interval and time after the change.

  Further, when the turbidity of the suspended solid concentration drainage immediately after the start of the blow of the suspended solid concentration drainage flowing through the blow line 7 falls below a predetermined value, a series of operations based on the next series of signals are collectively performed. A program for returning a changed interval for performing the operation and a changed time for opening the on-off valve 11 and the blow valve 13 to the basic interval and the basic time before the change, and outputting a signal for instructing the basic interval and the basic time It has.

  In addition, the control unit 16 collects a series of operations based on the series of signals as a whole at a basic time for performing the operations at a predetermined interval, and in the operations, the on-off valve 11, the on-off valve 12, the blow valve 13 and Basic time for closing the drain valve 14, basic time for driving the pump 5 at a predetermined rotational speed, basic time for opening the on-off valve 11 and blow valve 13, rotational speed of the pump 5, concentration of suspended matter The turbidity value of suspended solid-concentrated waste water immediately after the start of drainage, the time for which the series of operations based on the series of signals after the change is performed at a predetermined interval, and the on-off valve after the change 11 and a storage unit for storing the time during which the blow valve 13 is open.

  In this example, a series of operations based on the series of signals are grouped and a basic time for performing the operations at a predetermined interval. Among the operations, the on-off valve 11, on-off valve 12, blow valve 13 and Basic time when the drain valve 14 is closed, the number of rotations of the pump 5 when the suspended substance-concentrated drainage is forcedly circulated in the circulation circuit 10, and the basic time when the on-off valve 11 and the blow valve 13 are open (suspended substance The time during which the concentrated drainage is blown is set in the same manner as in the first example.

  The predetermined value of the turbidity of the suspended matter concentrated drainage immediately after the start of the blowing of the suspended matter concentrated drainage is when the turbidity of the suspended matter concentrated drainage immediately after the start of the blowing of the suspended matter concentrated drainage exceeds the predetermined value, Suspension discharged from the suspended solid concentration drainage line 6 by blow at a basic interval for performing a series of operations based on the series of signals and at a basic time for opening the on-off valve 11 and the blow valve 13. It is set as a value at which the blow ends before the turbidity of the substance-concentrated wastewater becomes constant.

  When the turbidity of the suspended matter concentrated drainage immediately after the start of the suspended matter concentrated drainage blow exceeds a predetermined value, it becomes a signal indicating that the degree of attachment of the suspended matter to the membrane surface of the filtration membrane part 3 has increased. Next, the interval of a series of operations for forcibly circulating the suspended matter concentrated wastewater and blowing the suspended matter concentrated wastewater in the circulation circuit 10 and the time during which the suspended matter concentrated wastewater is being blown are corrected intervals, corrected It is set separately as time. The correction interval and the correction time are set based on the interval and time at which the state in which the turbidity of the suspended solid-concentrated waste water whose turbidity exceeds a predetermined value is constant by blow is obtained. The interval of a series of operations for forcibly circulating the suspended matter concentrated wastewater and blowing the suspended matter concentrated wastewater is set to be shorter than the basic interval, and the opening time of the on-off valve 11 and the blow valve 13 is longer than the basic time. Set as

  When the turbidity of the suspended solid concentrated drainage immediately after the start of the suspended solid concentrated drainage blow is detected by the turbidimeter 17, and the turbidity of the suspended solid concentrated drainage exceeds a predetermined value, the circulation circuit 10 The basic interval of a series of operations for forcibly circulating the suspended solid concentrated wastewater and blowing the suspended solid concentrated wastewater in the correction interval, and the basic time for blowing the suspended solid concentrated wastewater in the corrected time It is supposed to change.

  With the water treatment system configured as described above, the method for preventing clogging of the filtration membrane portion according to the present invention is performed as follows.

  The operation of the water treatment system is similar to the first example, in which treated water is supplied from the raw water tank 1 to the filtration membrane unit 3 through the water supply line 2 by driving the pump 5, and treated water filtered by the filtration membrane unit 3 is supplied. It is performed so as to be stored in the storage tank 4. When a predetermined basic time elapses during the filtration operation, the control unit 16 has an on-off valve 11 arranged on the water supply line 2a, an on-off valve 12 arranged on the treated water line 2b, a blow valve 13 arranged on the blow line 7, and A closing command signal for closing the drain valve 14 disposed in the drain line 8 for a predetermined basic time and a driving command signal for driving the pump 5 at a predetermined number of revolutions are output. 12, the blow valve 13 and the drain valve 14 are closed for a predetermined basic time to constitute the circulation circuit 10, and the pump 5 is driven at a predetermined rotation speed. As a result, the suspended solid concentrated wastewater generated in the filtration membrane unit 3 circulates in the circulation circuit 10.

  By forcibly circulating the suspended matter concentrated waste water in the circulation circuit 10 in this way, the suspended matter adhering to the membrane surface of the filtration membrane unit 3 is separated from the membrane surface by the flow rate of the circulating water. When the basic time has elapsed, the control unit 16 outputs an opening command signal for opening the on-off valve 11 and the blow valve 13 for a basic time, and the on-off valve 11 and the blow valve 13 are opened in response to the signal. As a result, the suspended solid-concentrated waste water circulated in the circulation circuit 10 is blown from the blow line 7 so as to be pushed out by the treated water supplied from the raw water tank 1. By thus suspending the suspended matter concentrated waste water, the suspended material peeled off from the membrane surface of the filtration membrane section 3 is discharged from the blow line 7 together with the suspended material concentrated waste water.

  Further, by opening the on-off valve 11 and the blow valve 13, the turbidity of the suspended solid concentration drainage flowing through the blow line 7 is detected by a turbidimeter 17, and immediately after the suspension material concentrated drainage flow flowing through the blow line 7 is started. When the turbidity of the suspended matter concentrated wastewater exceeds a predetermined value, the control unit 16 sets the basic interval of a series of operations for forcibly circulating the suspended matter concentrated wastewater in the circulation circuit 10 and blowing the suspended matter concentrated wastewater. The basic time during which the suspended solid concentration drainage is blown, that is, the on-off valve 11 and the blow valve 13 are opened, is changed to the correction time at the correction interval, and the next operation is the correction interval and the correction time. Based on.

  After that, when the turbidity of the suspended solid concentration drainage immediately after the start of the suspended solid concentration drainage flow flowing through the blow line 7 falls below a predetermined value, the suspended solid concentration drainage is forcibly circulated and suspended in the circulation circuit. The correction interval of the series of operations for blowing the substance-concentrated waste water and the correction time for opening the on-off valve 11 and the blow valve 13 are changed to the basic interval before the change, the basic time, and the operation is the basic interval before the change, Performed based on basic time.

  As described above, the circulation circuit 10 is configured, and the suspension material concentrated waste water is forcibly circulated in the circulation circuit 10, so that the suspended material adhering to the membrane surface of the filtration membrane unit 3 is caused by the flow rate of the circulation water. It can be easily and more reliably peeled from the film surface. Thereafter, the separated suspended substance can be discharged from the suspended substance concentrated drainage line 6 together with the suspended substance concentrated drainage by blowing the suspended substance concentrated drainage. The clogging of 3 can be eliminated at an early stage.

  Further, as described above, when the suspended matter adhering to the membrane surface of the filtration membrane part 3 is peeled from the membrane surface, the membrane is obtained by circulating the suspended matter-concentrated waste water without supplying the water to be treated. Since the suspended matter adhering to the surface is peeled off, the discharge amount of the water to be treated for blowing can be reduced, that is, the waste water can be saved, which is economical.

  Furthermore, by detecting the turbidity of the suspended solid concentrated drainage immediately after the start of blowing the suspended solid concentrated drainage, the degree of adhesion of the suspended matter to the membrane surface of the filtration membrane part 3 can be known, When the turbidimeter 17 detects that the turbidity of the suspended solid concentrated drainage immediately after the start of blowing the concentrated concentrated wastewater exceeds a predetermined value, the suspended suspended solid concentrated wastewater is forced to circulate thereafter. By changing the interval between a series of operations for blowing the suspension and the time for blowing the suspended matter-concentrated waste water, the suspended matter adheres to the membrane surface of the filtration membrane part 3 as much as possible, and the filtration membrane part by the suspended substance The clogging of 3 can be eliminated at an early stage.

(4th example)
This example is an example of the fourth embodiment. Since the water treatment system of this example is the same as that of the said 2nd example shown in FIG. 2 except the program of the control part 16, and the memory | storage information of a memory | storage part, FIG. 2 is used and this example is demonstrated.

  In this example, as in the first example, the control unit 16 outputs an open / close command signal to the open / close valve 11, the open / close valve 12, the blow valve 13 and the drain valve 14, and sets the rotation speed of the pump 5 to the output frequency. A drive command signal for driving the pump 5 is output via an inverter 15 that is varied accordingly.

  And only at the time of starting, the control part 16 is the same as the 1st example, the on-off valve 11 arrange | positioned at the water supply line 2a, the on-off valve 12 arrange | positioned at the treated water line 2b, and the blow valve arrange | positioned at the blow line 7 13 and a drain command signal for closing the drain valve 14 disposed in the drain line 8 for a predetermined basic time, and a drive command signal for driving the pump 5 at a predetermined basic time for a predetermined basic time. After the basic time elapses, an opening command signal for opening the on-off valve 11 and the blow valve 13 for a predetermined basic time is output, and after the predetermined basic time for opening the blow valve 13, the on-off valve 12 and the drain valve 14 are turned on. A program for outputting an opening command signal for opening and a closing command signal for closing the blow valve 13 and outputting a driving command signal for driving the pump 5 at a normal rotational speed is provided.

  Further, in this example, the control unit 16 collects a series of operations based on the next series of signals and performs a predetermined basic interval for performing the operations and a basic time for opening the on-off valve 11 and the blow valve 13. The interval and time are changed to the interval and time set according to the turbidity of the suspended matter concentrated drainage immediately after the start of the blow of the suspended matter concentrated drainage flowing through the blow line 7 detected by the turbidimeter 17, and the changed interval and time are changed. The program which outputs the signal which commands is provided.

  In addition, the control unit 16 collects a series of operations based on the series of signals as a whole at a basic time for performing the operations at a predetermined interval, and in the operations, the on-off valve 11, the on-off valve 12, the blow valve 13 and Basic time for closing the drain valve 14, basic time for driving the pump 5 at a predetermined rotational speed, basic time for opening the on-off valve 11 and blow valve 13, rotational speed of the pump 5, concentration of suspended matter A series of operations based on the series of signals set according to the initial turbidity of the wastewater is collectively set according to the time for which the operation is performed at predetermined intervals and the initial turbidity of the suspended matter-concentrated wastewater. In addition, a storage unit is provided for storing a time during which the on-off valve 11 and the blow valve 13 are open.

  In this example, a series of operations based on the series of signals are grouped and a basic time for performing the operations at a predetermined interval. Among the operations, the on-off valve 11, on-off valve 12, blow valve 13 and Basic time when the drain valve 14 is closed, the number of rotations of the pump 5 when the suspended substance-concentrated drainage is forcedly circulated in the circulation circuit 10, and the basic time when the on-off valve 11 and the blow valve 13 are open (suspended substance The time during which the concentrated drainage is blown is set in the same manner as in the first example.

  Furthermore, the interval of performing the series of operations based on the series of signals as a whole is based on the turbidity of the suspended solid concentrated drainage immediately after the start of the suspended solid concentrated drainage blow, in addition to the basic interval. Separately set as the corresponding interval. This corresponding interval is based on the time during which suspended substance in the suspended substance concentrated wastewater adheres to the membrane surface of the filtration membrane part 3 and may become clogged. It is set as the corresponding interval according to the turbidity of the concentrated drainage.

  Further, the opening time of the on-off valve 11 and the blow valve 13 is set separately according to the turbidity of the suspended solid concentrated drainage immediately after the start of the suspended suspended solid concentrated drainage in addition to the basic time. Is done. This response time is determined based on the time required for the turbidity of the suspended solid concentrate drainage immediately after the start of the suspended concentrate concentrated drainage blow to become lower and constant due to the blow. It is set as the response time according to the turbidity of the turbid substance concentrated drainage.

  Then, as described above, the turbidity of the suspended matter concentrated wastewater immediately after the start of the suspended matter concentrated wastewater blow is detected, and the next suspended matter concentrated wastewater is forcibly circulated to blow the suspended matter concentrated wastewater. Suspended substance is forced to circulate suspended substance concentrated drainage set according to the turbidity of suspended substance concentrated drainage immediately after the start of the suspended substance concentrated drainage blow, and the interval of operation and suspension substance concentrated drainage blow time The corresponding interval of a series of operations for blowing concentrated wastewater and the corresponding time for blowing suspended material concentrated wastewater are changed.

  With the water treatment system configured as described above, the method for preventing clogging of the filtration membrane portion according to the present invention is performed as follows.

  The operation of the water treatment system is similar to the first example, in which treated water is supplied from the raw water tank 1 to the filtration membrane unit 3 through the water supply line 2 by driving the pump 5, and treated water filtered by the filtration membrane unit 3 is supplied. It is performed so as to be stored in the storage tank 4. And when filtration processing driving | running for predetermined time passes, the control part 16 has the on-off valve 11 arrange | positioned in the water supply line 2a, the on-off valve 12 arrange | positioned in the treated water line 2b, the blow valve 13 arrange | positioned in the blow line 7, and the drainage line 8 outputs a closing command signal for closing the drain valve 14 for a predetermined time and a driving command signal for driving the pump 5 at a predetermined number of revolutions. Upon receipt of such a signal, the on-off valve 11, the on-off valve 12, and the blow valve 13 and the drain valve 14 are closed for a predetermined time to constitute the circulation circuit 10, and the pump 5 is driven at a predetermined rotational speed. As a result, the suspended solid concentrated wastewater generated in the filtration membrane unit 3 circulates in the circulation circuit 10. By forcibly circulating the suspended matter concentrated waste water in the circulation circuit 10 in this way, the suspended matter adhering to the membrane surface of the filtration membrane unit 3 is separated from the membrane surface by the flow rate of the circulating water.

  When the predetermined time elapses, the control unit 16 outputs an opening command signal for opening the on-off valve 11 and the blow valve 13 for a predetermined time, and the on-off valve 11 and the blow valve 13 are opened in response to the signal. As a result, the suspended solid-concentrated waste water circulated in the circulation circuit 10 is blown from the blow line 7 so as to be pushed out by the treated water supplied from the raw water tank 1. By thus suspending the suspended matter concentrated waste water, the suspended material peeled off from the membrane surface of the filtration membrane section 3 is discharged from the blow line 7 together with the suspended material concentrated waste water.

  Further, by opening the on-off valve 11 and the blow valve 13, the turbidity of the suspended matter concentrated drainage immediately after the start of the blowing of the suspended matter concentrated drainage flowing through the blow line 7 is detected by the turbidimeter 17, and the control unit 16 The interval at which the series of operations based on the series of signals coming next is performed collectively and the time during which the on-off valve 11 and the blow valve 13 are open are set to the turbidity detected by the turbidimeter 17. The response interval and response time are changed to the corresponding response interval and response time, and a signal for instructing the changed response interval and response time is output. In response to the signal, the operation is performed based on the changed correspondence interval and the corresponding time.

  As described above, the circulation circuit 10 is configured, and the suspension material concentrated waste water is forcibly circulated in the circulation circuit 10, so that the suspended material adhering to the membrane surface of the filtration membrane unit 3 is caused by the flow rate of the circulation water. It can be easily and more reliably peeled off from the membrane surface. Thereafter, the suspended suspended matter concentrated drainage is suspended together with the suspended suspended matter concentrated drainage line 6 by blowing the suspended suspended matter concentrated drainage. Therefore, the clogging of the filtration membrane part 3 due to the suspended substance can be eliminated at an early stage.

  Further, as described above, when the suspended matter adhering to the membrane surface of the filtration membrane part 3 is peeled from the membrane surface, the membrane is obtained by circulating the suspended matter-concentrated waste water without supplying the water to be treated. Since the suspended matter adhering to the surface is peeled off, the discharge amount of the water to be treated for blowing can be reduced, that is, the waste water can be saved, which is economical.

  Further, by detecting the turbidity of the suspended matter concentrated drainage immediately after the start of the blowing of the suspended matter concentrated drainage, it is possible to know the degree of adhesion of the suspended matter to the membrane surface of the filtration membrane part 3, and the turbidity. Depending on the degree, the filtration membrane unit 3 can be changed by changing the interval of a series of operations for forcibly circulating the suspended solid concentrated wastewater and blowing the suspended solid concentrated wastewater and the time for blowing the suspended solid concentrated wastewater. As a result, the amount of suspended substances adhering to the membrane surface is reduced as much as possible, and the clogging of the filtration membrane part 3 due to suspended substances can be eliminated at an early stage, and wasteful discharge of treated water for blowing can be prevented. In addition, the amount of water to be treated can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic explanatory drawing which shows an example of the water treatment system which enforces the clogging prevention method of the reverse osmosis membrane part which concerns on this invention. Schematic explanatory drawing which shows the other example of the water treatment system which enforces the clogging prevention method of the reverse osmosis membrane part which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw water tank 2 Water supply line 2a Water supply line 2b Treated water line 3 Filtration membrane part 4 Storage tank 5 Pump 6 Suspended substance concentration drainage line 7 Blow line 8 Drainage line 9 Circulation line 10 Circulation circuit 11 On-off valve 12 On-off valve 13 Blow valve 14 Drain valve 15 Inverter 16 Control unit 17 Turbidimeter

Claims (4)

A method of preventing clogging of the filtration membrane part by blowing the suspended matter concentrated waste water generated in the filtration membrane part in the process of filtering the water to be treated at predetermined intervals,
A circulation circuit is formed by connecting a suspended water concentration drainage line connected to the upstream side of the filtration membrane unit and a suspension membrane concentration drainage line to the filtration membrane unit, and before the suspension material concentration drainage blow, the filtration is performed. After closing the water supply line upstream of the membrane part, the treated water line downstream of the filtration membrane part and the suspended solid concentration drainage line, and forcibly circulating the suspended matter concentrated drainage in the circulation circuit, the filtration membrane part A method for preventing clogging of a filtration membrane section, characterized by opening a water supply line and a suspended matter concentration drainage line on the upstream side of the filter and blowing the suspended matter concentration drainage.   2. The filtration membrane unit according to claim 1, wherein the turbidity of the suspended solid concentration drainage is observed when the suspended solid concentration drainage is blown, and the blow is stopped when the turbidity becomes constant. How to prevent clogging.   Immediately after the start of the blowing of the suspended solid concentrated drainage, the turbidity of the suspended solid concentrated drainage is detected, and when the turbidity exceeds a predetermined value, the suspended suspended solid concentrated drainage is forcibly circulated to suspend the suspended suspended solid concentrated drainage. 2. The method for preventing clogging of the filtration membrane part according to claim 1, wherein an interval between a series of operations for blowing the water and / or a time for blowing the suspended matter concentrated waste water is changed.   Immediately after the start of the blowing of the suspended solid concentration waste water, the turbidity of the suspended solid concentration waste water is detected, and the next suspended solid concentration waste water is forcibly circulated to blow the suspended solid concentration waste water according to the turbidity. 2. The method for preventing clogging of the filtration membrane section according to claim 1, wherein the operation interval and / or the time for blowing the suspended matter-concentrated waste water is changed.

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