JPH06190251A - Method and apparatus for treatment of water containing turbid component - Google Patents

Abstract

PURPOSE:To efficiently reduce the volume of turbid components and to discard these turbid components by using water contg. the turbid components as original water and removing the turbid components by filtration. CONSTITUTION:Waste water contg. the flocs largely agglomerated by addition of a high-molecular flocculaant in a flocculation chamber 7 is sent through a water feed line 92 by a membrane water feed pump 91 from a pump pit 9 of the flocculation chamber 7 into a filter membrane device 11. The filter membrane device 11 has a tubular internal pressure type precision filter membrane 11a and is so provided that the waste water is passed in the pipe and is then circulated by the cross flow to return the waste water from a circulating return line 12 to the pump pit 9 of the flocculation chamber 7. The SS components (turbid components) in the waste liquid passed by the cross flow is filtered by the filter membrane 11a and the permeated water passed to the outer side of the membrane 11a is taken out as treated water 16 from a permeated water line 14 through a back washing water holding tank 15. As a result, the clean permeated water is obtd. and the turbid components are efficiently reduced in the volume and are discarded.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for treating water containing turbidity components as raw water to remove the turbidity components by filtration to obtain clean permeated water, and to efficiently reduce the turbidity components. The present invention relates to a treatment method that can be converted into a waste and a device used for these methods.

[0002]

2. Description of the Related Art Generally, "SS (Suspended Solid)"
It is widely practiced to remove water from raw water containing turbidity components to clean the water.The conventional method is to add a coagulant to the raw water to remove fine particles in the water. The turbid components are aggregated to form flocs, which are subjected to solid-liquid separation in the flocculation sedimentation layer, and the supernatant water is filtered with a filter to obtain clear filtered water, while the flocs precipitated in the flocculation sedimentation layer are sludge. There is known a method in which the sludge is concentrated in a concentrating tank, recovered as sludge, further subjected to an appropriate dehydration treatment to reduce the volume, and then treated as waste.

Of these methods, recently,
Attention has been focused on a filtration membrane method that has excellent filtration performance as a filtration means and can be installed in a small volume, and in particular, a method of using a hollow fiber type filtration membrane or the like as an internal pressure type.

FIG. 12 shows an outline of the flow of an example of a water treatment device using such a filtration membrane. In this figure, 201 is a coagulation tank into which raw water is introduced, and a flocculant is added to the raw water to coarsely flocculate turbid components contained therein. The water containing the flocs flows into the pump pit 202 and is passed by the pump 203 into the pipe of the filter 204 having the hollow fiber type filtration membrane in a cross-flow format, and the permeated water that has passed through the membrane is discharged to the outside of the system ( Alternatively, the water is sent to an appropriate treatment device in the next stage), and the water on the non-filtration side is returned to the pump pit 202.

In this way, the floc concentration in the water flowing in the circulation system formed by the pump pit 202 and the filter 204 gradually increases. Then, from the middle of the water supply line where the pump pit 202 sends the circulating water to the filter 204, the water in which the flocs are concentrated by the above is withdrawn into the concentration tank 205 at an appropriate time and in an appropriate amount, and left standing for a predetermined time. The accumulated flocs (hereinafter referred to as “sludge”) that have settled and separated from the lower part of the concentration tank 205 at this point are extracted into a dehydrator 206, dehydrated and treated as waste. On the other hand, if such a filtration operation is continued, suspended components will adhere to the membrane surface of the filtration membrane, and the flow rate of the permeated water obtained will gradually decrease. While continuing the supply of water, the washing operation is performed by flushing backwash water from the outside (permeate side) of the membrane to wash away suspended matter adhering to the membrane surface. And stop and repeat the filtration as described above.

The filter used in the waste water treatment apparatus having such a structure uses a hollow fiber type filtration membrane of an internal pressure type, and a part of the waste water flowing in the membrane tube is pumped without passing through the filtration membrane. It is operated as a cross-flow method of returning to the pit 202. At this time, for the purpose of obtaining a high permeated water, for example, the turbidity component of the wastewater is not attached to the membrane surface (separation membrane surface) of the filtration membrane as much as possible, and the wastewater is supplied at a high flow rate so that a high permeated water amount can be obtained. A flushing method or an operation method in which the above-mentioned backwashing is frequently performed to prevent the turbid component from adhering to the membrane surface so much is adopted. Therefore, the concentration of sludge in backwash wastewater is generally low.

[0007]

The above-mentioned water treatment method shown in FIG. 12 is essentially to suppress as much as possible the decrease of the permeation component due to the adherence of the turbidity component on the filtration membrane, and the waste water containing the turbidity component is crossed. Flow through the flow to obtain as much permeate as possible on the permeate side, while increasing the concentration of suspended matter in the circulating water on the non-filtration (permeate) side as much as possible to balance the supply amount of raw water and the flow rate of permeate. However, it is intended to obtain water containing a relatively high concentration of turbidity components from this circulation system. The reason for increasing the concentration of suspended matter in the circulating water in the circulation system is to reduce the burden of concentrating, dehydrating, and reducing the volume of sludge extracted from the system.

[0008] However, according to this method, the suspended matter component in the circulating water repeatedly circulated in the filtration membrane becomes higher in concentration than the SS concentration of the raw water, so that the suspended matter component is likely to adhere and deposit on the surface of the filtration membrane. This is not necessarily an advantageous method for the purpose of operating while suppressing the adherence of turbid components to the membrane surface as much as possible.

That is, the conventional method has an extremely high flow velocity on the membrane surface (usually 3 m / sec) so as not to attach turbidity to the membrane surface.
As described above), the ratio of the circulation flow rate to the permeation flow rate is usually 10 or more, and when it is high, it is 30 or more, which is a very wasteful process in terms of energy. Furthermore, in terms of equipment, there is a major drawback in that auxiliary equipment such as pumps and piping are also large.

Further, the solid-liquid separation by the conventional membrane treatment is
The suspended matter concentration in the circulation system cannot be increased so much as to suppress the deposition of suspended matter on the surface of the filtration membrane as much as possible.
The concentration of sludge discharged to the outside of the system is at most 10,000-200
It remains at 00 mg / l. Therefore, at this concentration, dehydration by a direct dehydrator cannot be said to be an advantageous method from the viewpoint of the water content and the amount of dehydration aid used, and a concentration tank for further concentrating sludge is required.

Further, when the turbidity component in the water has a relatively low concentration, the amount of deposits adhering to the membrane surface is small, so in terms of energy efficiency, the water flow of the total filtration method is more effective than the crossflow method. Although it is considered preferable to carry out filtration, since water flow of cross-flow method has been common knowledge in the past, the water treatment method of total-volume filtration method is not so common.

In view of the current state of the art as described above, the present inventor diligently studied a treatment method that can effectively utilize a membrane filtration system having many advantages, and a novel water treatment apparatus that can be used for the treatment method. Layered.

In the course of this examination, the present inventor has detailed the phenomenon appearing in the process of filtration operation without being restricted by the concept of the conventional method of "operating while suppressing the adherence of turbid components to the membrane surface as much as possible". As a result of the investigation, it was found that there are some points to be noted. In other words, it should be noted that the turbidity component deposited and deposited on the surface of the filtration membrane has a cylindrical structure with a loosely bound state in which it is destroyed by a relatively weak force, and has the property of exhibiting high sedimentation properties. It was done. Here, I realized that if the highly sludge-forming tubular sludge could be taken out without substantially destroying the tubular shape, all the various problems of the conventional method could be solved.

The present invention has been made from the above viewpoints, and an object thereof is to remove turbid components contained in raw water.
It is an object of the present invention to provide a novel water treatment method and apparatus that can be quickly settled in the lower part of a tank and taken out in a state where it can be easily separated from raw water.

Another object of the present invention is to extract the sludge having the cylindrical structure having the rapid settling property as described above from the lower part of the tank in which it settled to the outside without a large amount of water. In addition, a conventional concentration tank for sludge separation can be dispensed with, and a new water treatment method and device can be provided which can reduce the facility volume by immediately dehydrating the extracted sludge. .

Still another object of the present invention is that, depending on the turbidity component content of the raw water, for example, when the turbidity component content is small, a total filtration method excellent in energy efficiency can be adopted, and high turbidity is achieved. In the case of raw water containing quality components, since it is treated with a low amount of circulating water, a new energy-saving water treatment method and device capable of obtaining the same amount of permeated water as the conventional method with a small capacity pump is provided. .

Another object of the present invention is to provide a novel water treatment method and apparatus which can be easily automated.

[0018]

In order to achieve the above object, the present inventor has completed the invention described in each of the claims.

One of the features of the present invention is that the raw water containing the turbidity component is caused to flow in the tube of the tubular filtration membrane, and the turbidity component contained in the raw water is deposited on the inner peripheral surface of the membrane while the diameter of the membrane is being increased. Characterized by a filtering operation that causes permeated water to flow out to the outside in the direction, and a washing operation that interrupts this filtering operation to remove the suspended components adhered and deposited on the inner peripheral surface of the tubular filtration membrane from the inner peripheral surface of the membrane, The most typical feature is that the tubular body of the turbid component adhered and deposited in a tubular shape on the inner peripheral surface of the tubular filtration membrane is separated from the membrane surface without substantially destroying the tubular structure, A peeling operation in which backwash water is flown from the outer side to the inner side in the radial direction of the membrane, and an extruding operation in which a tubular body of suspended components separated by this is extruded from the inside of the tube in the axial direction by the water flow in the axial direction of the tubular filtration membrane. There is a place to do and sequentially.

That is, when a water-passing operation is performed, sludge gradually adheres to the inner surface of the filtration membrane as shown in FIG.
When waste water with a concentration of 500 mg / l is passed for 1-2 hours,
At the end of water flow, the sludge layer has a thickness of about 1 to 2 mm. The amount of permeated water also decreases as the sludge layer becomes thicker. For example, what was about 300 liters / m ² · h at the beginning of water passage was 100 liters / m ² · h at the end of water passage.
It decreases to about h. Therefore, generally, when the amount of permeated water decreases to about 1/2 to 1/3 of the initial amount of water passed, the operation of removing the sludge adhered by the above-described backwashing of the present invention is performed.

By sequentially performing the above-described peeling operation and extrusion operation, as shown in FIG. 11, the tubular sludge adhered and deposited on the inner surface of the filtration membrane is extruded from the filtration membrane without being substantially destroyed. It

The peeling operation and the extruding operation are performed in order so that the extruding operation for exfoliating the tubular body from the film surface precedes so that the extruding of the tubular body in the axial direction becomes smooth. Is. Permeate water or raw water may be used as the extrusion water.

In the method of the present invention, the peeling operation for peeling the cylindrical body of the turbid component adhered to the inner surface of the filtration membrane from the membrane surface without substantially destroying it is performed, for example, from the outside of the filtration membrane. This is an operation in which water is caused to flow in the direction opposite to that of filtration, but has completely different properties from the backwashing at a high flow rate, which is carried out in the conventional method. That is, in the conventional method, the backwash water is made to flow from the outer side to the inner side of the membrane while the raw water is kept flowing in the tube of the filtration membrane without interrupting the filtration operation. The adhered volume that is presenting as a body is destroyed by the flow of raw water, so that the sludge becomes finer and has poor sedimentation properties. In order to perform the peeling without substantially destroying the tubular body, as described above, the filtration operation is once interrupted, the backwash water is then flowed to perform the peeling operation, and then the backwash water is removed. It is important to stop the inflow and to extrude the exfoliated tubular sludge.

In the latter stage of backwashing, the extruded water for axially extruding the tubular body from the end portion of the membrane must also be passed through without substantially destroying the peeled tubular body. Is generally 0.5 to 2 m / sec, preferably 0.
It is preferable to flow at a flow rate of about 5 to 1.0 m / sec. Either permeated water or raw water may be used as the extruded water.

The tubular body of the turbid component extruded from the tubular filtration membrane without being substantially destroyed by the method of the present invention is, in most cases, a hollow tubular body, as will be confirmed in the examples described later. It has a (macaroni-like) shape,
It can be seen that the structure is formed in a weakly bonded state in which it is relatively easily broken when a mechanical force is applied. Here, “without substantially destroying” means operating as little as possible the rate at which the tubular body is destroyed and returns to the floc state before attachment and deposition, but the rate of returning to the floc state is 50. %, The effect of the present invention is not sufficient. Therefore, the ratio is generally 20% or less, preferably 10% or less.

According to the method of the present invention, when the turbidity component of the raw water has a high turbidity (generally SS≈1000 mg / l or more), the raw water is fed to the tubular filtration membrane, and the membrane surface velocity is set to 0. 1 to
1 m / sec, preferably 0.2 to 0.5 m / sec, a method of flowing in a cross flow at a lower flow rate than the conventional one is preferably adopted, while the turbid component of raw water has a low turbidity (generally SS ≈ 1000 mg / L) or less), the total filtration method is preferable for the tubular filtration membrane.

The above-mentioned membrane surface flow velocity is obtained by dividing the flow rate of non-permeate water (usually this becomes circulating water) flowing out of the tubular filtration membrane without being filtered by the opening cross-sectional area of the tubular filtration membrane. Is. Therefore, in the case of the total filtration method, the membrane surface flow velocity is zero.

In the present invention, by increasing the amount of circulating water, the flow velocity on the membrane surface with respect to the tubular filtration membrane is increased (usually 3 m / sec or more), and the operation is performed while suppressing the adherence of turbid components to the membrane surface as much as possible. Instead of being confined to the conventional way of thinking, the turbidity component is made to actively adhere to the membrane surface, so even when performing filtration by the cross flow method, the circulating water volume is significantly smaller than in the conventional case. Therefore, various advantages such as a small capacity of the pump for supplying raw water to the tubular filtration membrane can be obtained.

The apparatus of the present invention used for carrying out the above-mentioned method is characterized by a tubular filtration membrane provided so that raw water containing turbid components flows in the tube in an axial direction, and a tubular filtration membrane in the tubular filtration membrane. Raw water flow means for flowing the above-mentioned raw water to flow out permeated water from the membrane peripheral surface to the outside in the radial direction of the membrane and filtration of suspended matter, and a cylindrical body of suspended matter adhered and deposited on the inner peripheral surface of the membrane. Backwash water flow means for flowing backwash water from the outside to the inside in the radial direction of the tubular filtration membrane to separate it from the membrane surface, and the tubular body of the suspended component peeled from the membrane surface of the tubular filtration membrane. The extruding water passage means for extruding with running water in the axial direction and the passage through the raw water passage means are intermittently interrupted, and the backwash water passage means and the extruding water passage means are sequentially passed. It is equipped with water control means.

The tubular filtration membrane used in the present invention is
Although the name is not particularly limited, generally so-called hollow fiber type or tubular type can be used, and the type of membrane includes microfiltration membrane, ultrafiltration membrane, etc. Can be used. The inner diameter of the filtration membrane used is 2 to 10 mm, preferably 4 to 6 mm. The length of the tubular filtration membrane is not particularly limited, but is usually about 0.5 to 3 m, preferably about 0.5 to 1 m.

Since the method and apparatus of the present invention can be applied to raw water containing a relatively high concentration of turbidity components, it can be used for various types of wastewater treatment in addition to treatment facilities for factory wastewater and power plant wastewater. It is applicable not only to wastewater treatment but also to removal of turbid components such as industrial water and tap water.

In particular, the apparatus of the present invention has a tank for allowing the bottom of the tubular body made of the turbid component extruded from the tubular filtration membrane to be settled at the bottom, and the tubular body of the settled turbid component is externally supplied from the bottom of the tank. As a device with a structure provided with a means for extracting to
More preferably, the tubular filtration membrane is installed vertically in the filtration tower,
The extruded water flow means is used as a device for passing water so that the tubular body of the turbid component separated from the inner surface of the tubular filtration membrane is pushed downward. In particular, according to the method in which the tubular filtration membrane is installed vertically in the filtration tower and the extruded water is caused to flow in a downward flow, the filtration tower itself can be used as a tank for causing the sedimentation of the tubular body, so that the installation volume of the device is increased. Can be further reduced.

According to these devices, the cylindrical body having a high sedimentation property rapidly settles in the lower part of the tank and can be quickly discharged by the means for drawing it out of the tank.

Further, in such an apparatus, the tubular body extracted to the outside of the tank can be directly sent to the dehydrating means without performing the concentrating means such as the conventional concentrating tank to perform the dehydrating treatment. It is possible to reduce the equipment volume.

The apparatus of the present invention is not limited to the apparatus of the type in which the raw water is flowed through the filtration membrane in a cross-flow, but the operation of the conventional method of suppressing the deposition of turbid components on the surface of the filtration membrane during the filtration operation. Since it is not intended at all, it can be effectively applied to a system in which raw water is made to flow through a filtration membrane by a total volume filtration system. In the case of a method of flowing raw water by this total volume filtration method, for example, one end side of a filter membrane of open both ends is normally closed so that raw water does not flow, and a flow passage is formed so that extruded water flows from this one end side during cleaning. Extrusion water flow means for switching can be provided.

[0036]

【Example】

Example 1 In FIG. 1, 4 is a reaction tank, and wastewater sent from a wastewater storage tank by a pump (neither is shown) flows in from an inflow line 1. In this reaction tank 4, a coagulant 2 (aluminum sulfate, aluminum salt such as polyaluminum chloride,
Iron salt such as ferric chloride) is added, and a pH adjusting agent 3 of acid (hydrochloric acid, sulfuric acid, etc.) and alkali (sodium hydroxide, etc.) is injected to flocculate SS components in the waste water to cause flocs. Is generated. 5 is a stirrer.

The wastewater in which flocs are generated by the addition of the flocculant is sent to the flocculation tank 7, where the polymer flocculant 6 is further added to coarsen the flocs. 8 is a stirrer. The coagulation tank 7 in this example is a cylindrical solid substance contained in the backwash water sent from the tubular filtration membrane by the circulation system described later (a turbid substance that has adhered and accumulated on the inner surface of the tubular filtration membrane to form a tubular suspended matter). It also serves as a tank for settling and separating (components), and for that reason, its bottom is provided in a cone shape (inverted cone shape).

The waste water containing flocs coarsened in the coagulation tank 7 is filtered from the pump pit 9 of the coagulation tank 7 by the membrane water supply pump 91 through the water supply line 92 to the filtration membrane device 11
Sent to. In addition, a part of the wastewater sent to the filtration membrane device 11 through the water supply line 92 by the membrane water supply pump 91 is pumped by the return piping line 10 to the coagulation tank 7 in order to adjust the pressure and prevent the deposition of SS in the pump pit 9. Returned to pit 9.

The filtration membrane device 11 of this embodiment is provided with a tubular internal pressure type microfiltration membrane 11a, and a waste water is passed through the inside of the pipe and then is returned from the circulation return line 12 to the pump pit 9 of the coagulation tank 7 described above. The SS component in the waste water that is flowed in a cross flow is filtered by the membrane surface of the filtration membrane, and the permeate that has passed to the outside of the membrane is retained as backwash water from the permeate line 14. It is taken out as treated water 16 through the tank 15. Further, for example, as shown in FIG. 4, this filtration membrane device 11 has a raw water inlet 301 at a lower end, a non-permeate outlet 302 at an upper end, and a permeate outlet 303 at a side wall in a container 304, each having an inner diameter of about several mm. A large number of the tubular filtration membranes 11a of FIG.
The upper and lower ends of 1a are supported in a liquid-tight manner by supporting members 305 and 306, raw water is supplied into the container 304 through the raw water inlet 301, and the chamber A below the supporting member 306 passes through the inside of the tubular filtration membrane 11a. The permeated water that has permeated the filtration membrane is obtained in the chamber C between the upper and lower support members while flowing into the chamber B above the support member 305, and the permeated water obtained is used as the permeate outlet 30.
Although a type in which the fluid flows from the container 3 to the outside of the container 304 is adopted, the structure is not particularly limited to this.

The above structure shows a structure for performing a filtering operation by the cross flow system, and for this purpose, the automatic valves 101, 102, 103, 10 provided in the respective piping lines.
4 is open circuit.

When performing the filtration operation by the total volume filtration method, the automatic valves 101, 102 and 103 are opened, and
Should be closed.

Next, the washing operation performed after performing the above-described filtration operation will be described with reference to FIGS. 2 and 3.

Reference numeral 18 denotes an air storage tank for sending backwash water. After the filtration operation is interrupted, a normally closed automatic valve 108 is opened and pressure air is backwashed by a command from a controller (not shown). The permeated water stored in the backwash water holding tank by being sent to the holding tank 15 is passed through the backwash water inlet line 17 and the normally closed automatic valve 105 opened, and the filtration membrane device 11
The tubular filtration membrane 11a is backwashed with water from the outside to the inside of the tube. The backwash water that has been passed is sent to the flocculation tank 7 through a backwash water discharge line 13 that is connected to the circulation return line 12 through a normally closed automatic valve 107. The above-mentioned configuration of the piping, the automatic valve, and the like is for performing the operation for separating the cylindrical deposits from the inner surface of the filtration membrane in the cleaning process. In this step, each of the automatic valves 101, 10 opened in the filtration operation is
2, 103 and 104 are closed (see FIG. 2).

Next, the structure for the extruding operation of axially extruding the tubular sludge exfoliated in the exfoliation step from the end of the tubular filtration membrane will be described. From the air storage tank 18 for the backwash water supply, The permeated water in the backwash water holding tank 15 is passed through the normally closed automatic valve 106, which is opened, to the inside of the tubular filtration membrane of the filtration membrane device 11, and is peeled by the above peeling operation. Circulation return line 12
Side, and further, automatic valve 107, backwash water discharge line 13
It is provided so as to be sent to the flocculation tank 7 via the (see FIG. 3). Raw water may be used as the extruded water in FIG.

The cylindrical deposits (sludge) contained in the backwash water sent to the coagulation tank 7 quickly settle in the coagulation tank 7 and settle at the bottom of the tank.

The switching of the opening and closing of each automatic valve and the switching of the operation of each pump are performed as follows. That is, in this example, the permeated water amount detector 31 provided in the permeated water line 14 that causes the permeated water to flow out from the filtration membrane device sends variation information of the permeated water amount to a control device (not shown), and the back washing start condition is previously set in the control device. By comparing the value of the amount of permeated water detected with the threshold value defined as, it is provided to start a predetermined backwash step when the amount of permeated water detected falls below a predetermined threshold value. . The procedure of the backwash process should be performed automatically by a control program that controls the opening and closing of each automatic valve and the time for sending air from the air tank 18 for sending the backwash water by using a timer or the like. You can

Next, the construction for extracting the cylindrical sludge settling at the bottom of the flocculation tank 7 and dehydrating it will be described.

Reference numeral 20 denotes a sludge discharge line connected to the bottom of the flocculation tank 7. In this example, the normally closed automatic valve 109 provided in the middle of the sludge discharge line is periodically opened to open the flocculation tank 7. It is drawn out by the difference between the water level inside and the water level in the next stage sludge storage tank 21. The sludge withdrawal pump may be used for the withdrawal.

The sludge drawn into the sludge storage tank 21 is uniformly stirred in this tank by the agitator 22 and sent to the dehydrator 25 by the sludge supply pump 23, and the dewatered cake 26
Be shipped as. If necessary, a dehydration aid 24 may be added before the dehydration. The dehydrated filtrate 27 discharged from the dehydrator 25 is stored in a dehydrated filtrate tank 28, and the filtrate water supply pump 2
9 is sent to the reaction tank 4 or a waste water storage tank (not shown) through the filtrate water supply line 30.

Embodiment 2 This embodiment shown in FIG. 5 is carried out except that the flocculation tank 7 of FIG. 1 is made independent of the solids separating section 71 in the first half and the flocculation section 72 in the latter half. The configuration is the same as in Example 1.

In the case of this example, since the bottom portion having the cone shape can be limited to the solid content separating portion 71, the construction of the tank becomes easy.

Embodiment 3 In this embodiment shown in FIG. 6, the bottom 111e of the filtration tower 111a constituting the filtration membrane device 111 is formed in a cone shape,
The example of the apparatus which pushed out the extrusion in the washing | cleaning process of the cylindrical sludge adhered and accumulated inside the vertical installation filtration membrane 111d is shown.

In this example, in order to make the extruding direction of the tubular sludge downward, the extruded water is passed from the upper chamber 111b of the filtration tower 111a through the inside of the filtration membrane to the lower chamber 11 of the filtration tower 111a.
It is provided so as to flow downward to 1c, while excess water in the filtration tower is returned to the pump pit 9 of the coagulation tank 7 through the backwash water return line 112. Further, with such a configuration, the tubular sludge will settle at the bottom of the filtration membrane device 111, not at the coagulation tank 7, so that the sludge drawing line 2
0, the normally closed automatic valve 109 that is opened periodically, the sludge supply tank 21 and the like are connected to the bottom of the filtration membrane device 111.

The other structure is the same as that of the first embodiment in which the circulating water is flowed by the cross flow.

FIG. 7 is a partially enlarged view of the filtration membrane device 111 in this example, which normally includes the automatic valve 1 from the water supply line 92.
01-lower chamber 111c of filtration tower 111a-filtration membrane 111
The waste water flows to the d-upper chamber 111b-circulation return line 12, the suspended matter is filtered on the inner surface of the filtration membrane, and the permeated water flows from the automatic valve 102 to the permeated water line 14 to perform a filtration step. At this time, the automatic valves 106, 107, 109 are closed.

Next, in the cleaning process, first, the automatic valves 101 and 104 are closed and the automatic valves 102 and 1 are closed.
07 is opened and the backwash water from the backwash water holding tank (not shown) is sent through the permeate line 14 to flow from the outer side to the inner side of the filtration membrane to separate the tubular sludge.

Following this, next, the automatic valve 102 is closed and the automatic valve 106 is opened to remove the backwash water from the upper chamber 11 of the filtration tower.
The tubular sludge that has flowed down from 1b into the filtration membrane and has been peeled off is extruded into the lower chamber 111c. The extruded tubular sludge quickly settles and deposits on the bottom of the filtration tower 111a, while
Excess water in the filtration tower 111a is backwashed water return line 112.
It is discharged to the outside of the tower via.

Embodiment 4 Although this embodiment is not particularly shown, for example, the filtration membrane device 111 is operated by the total filtration method by normally closing the automatic valve 104 provided in the middle of the circulation return line 12 of FIG. This is the case. Other configurations and switching of opening and closing of each automatic valve and the like in the cleaning process are performed in the same manner as in the third embodiment.

According to this example, it is possible to easily operate the total filtration method when the concentration of the turbidity components contained in the raw water is relatively low.

Test Example 1 A water treatment operation according to the method of the present invention was carried out under the following conditions by a cross flow system using the apparatus shown in FIG.

Conditions Filtration membrane device: Nitto Denko KK internal pressure type tubular microfiltration membrane (inner diameter 5.5 mm) Raw water: Thermal power plant waste water, SS concentration 4760 m
g / l Filtration operation conditions: Membrane inlet pressure of about 1.6 kg / cm ² ,
Membrane surface flow rate about 0.2 m / sec (circulation water amount / permeate amount ratio (circulation ratio) = 5) Cleaning operation conditions: stripping operation ... Backwash water pressure about 1.6 kg / cm ² hours 5 seconds Extrusion operation・ ・ ・ Extrusion water inflow rate 0.5 m / sec Extrusion water amount about 400 ml Filtration operation is performed for 30 minutes under the above-mentioned filtration conditions, and then the filtration operation is stopped to perform the washing operation as one cycle. When 5 cycles were repeated, tubular sludge with a solid concentration of 5.5 to 5.7% was discharged from the inside of the tubular filtration membrane in the washing operation of each cycle.
It quickly settled to the bottom of the flocculation tank.

By the way, the washing wastewater containing the tubular sludge taken out from the bottom of the coagulation tank was put into a graduated cylinder having a height of 30 cm and a capacity of 1 liter, and it was examined within 1 minute that the sludge settled with time. All of the tubular sludge settled on the bottom of the graduated cylinder.

The relationship between the filtration time and the amount of permeated water in the filtration operation of this test is shown in FIG.

Test Example 2 When the same apparatus as in Test Example 1 was used to perform water treatment by the method of the present invention by the cross flow method and the SS concentration of the raw water changed, what was the solid concentration of the obtained tubular sludge? To see if it changes.

The filtering operation conditions and the washing operation conditions are as follows.

Raw water: Wastewater from power plant Filtration operating conditions: Membrane inlet pressure of about 1.6 kg / cm ² ,
Membrane surface flow rate about 0.2 m / sec (circulation ratio 5) Washing operation condition: Peeling operation ... Backwash water pressure about 1.6 kg / cm ² hours 5-10 seconds Extrusion operation ... Extrusion water inflow speed 0.5 m / sec Extruded water amount about 400 ml The results are shown in Table 1 below.

[0067]

[Table 1]

As can be seen from the results of Table 1, the solid content of the tubular sludge obtained by backwashing was almost constant regardless of the initial SS concentration, and its sedimentation property was also very good.

Test Example 3 Using the apparatus of FIG. 1, a circulation return line 1 was used during the filtration operation.
The automatic valve 104 attached to No. 2 was closed, and the water treatment operation of the present invention was performed by the total volume filtration method.

The test conditions are as follows. The filtration membrane device used was the same as in Test Example 1.

Raw water: Wastewater from power plant, SS concentration 797 mg / l Filtration operating condition: Membrane inlet pressure about 1.6 kg / cm ² Washing operating condition: Stripping operation ... Backwashing water pressure about 1.6 kg / cm ² extrusion Operation ... Extruded water inflow rate 0.5 m / sec When filtration operation and washing operation under the above conditions were performed for 2 cycles, sedimentation property of solid content of about 5.5% by washing operation in any cycle A good tubular sludge was obtained.

The relationship between the filtration time and the amount of permeated water at this time is shown in FIG.

[0073]

As described above, according to the present invention, the following various effects can be obtained.

The turbidity component of the tubular body adhered and deposited on the inner surface of the tubular filtration membrane is extruded from the inside of the filtration membrane tube without substantially destroying the tubular shape, and the tubular structure is formed although the binding force is weak. As sludge with high sedimentation property, it can settle down to the bottom of the tank quickly and can be easily separated from raw water.

As a result, compared with the conventional case where the floating flocs extract the circulating water containing a high concentration out of the system, a large amount of water is added to the sludge having a cylindrical structure and having a high sedimentation property. Without the need for a conventional concentration tank for sludge concentration, the installation volume of equipment can be reduced, and the extracted sludge can be immediately sent to dehydration means for dehydration processing. Therefore, the processing can be speeded up.

Further, since the filtration operation is performed while positively adhering and depositing the turbidity component on the membrane surface, even if the raw water has a low concentration of the turbidity component, there is no need to perform circulation concentration for a long time as in the conventional case. A sludge having a high concentration and a high sedimentation property can be obtained by a short-time filtration operation. Therefore, the present invention can be applied regardless of the content of the turbid component of the raw water. Particularly, in the present invention, when the content of the turbid component is small, it is possible to carry out the operation of the total amount filtration system, so that it is possible to provide the device excellent in energy efficiency according to the content of the turbid component.

High turbidity concentration (SS≈1000 mg
(/ L or more) When treating raw water with the cross-flow method, the circulation flow rate can be reduced compared to the conventional method, and the flow rate of the circulation water to the filtration membrane can be set low, so the capacity of the pump for circulating water can be small, Furthermore, the turbidity concentration is low (SS
≅1000 mg / l or less), a circulating flow is not required and the pump capacity can be further reduced, so that the operating energy consumed can be reduced.

The time of the backwashing operation including the filtering operation, the peeling operation, and the extrusion operation usually changes in relation to the concentration of the turbid component, but the water flow control for each operation is performed by, for example, reducing the amount of permeated water. Since it can be simply performed with the degree as a guide, automation can be easily realized.

Due to the various advantages as described above, the features of the filtration membrane type water treatment apparatus having a small installation volume and suitable for automated operation can be more effectively exerted by the present invention. The effect of practical implementation is extremely large.

[Brief description of drawings]

FIG. 1 is a diagram showing a flow of a configuration of a water treatment device of Example 1, and a thick line in the diagram shows a flow of water during a filtering operation.

FIG. 2 shows a flow of water when a tubular sludge peeling operation is performed in a cleaning process of Example 1.

FIG. 3 shows a flow of water when a tubular sludge is extruded in the washing process of Example 1.

FIG. 4 is a schematic cross-sectional view of a membrane filtration device used in the water treatment device of Example 1.

FIG. 5 is a flowchart showing a part of the configuration of the water treatment device according to the second embodiment.

FIG. 6 is a flowchart showing a part of the configuration of a water treatment device according to a third embodiment.

FIG. 7 is an enlarged view showing the configuration of the filtration membrane device of the third embodiment.

FIG. 8 is a diagram showing a relationship between a filtration time and a permeated water amount in Test Example 1.

FIG. 9 is a diagram showing a relationship between a filtration time and a permeated water amount in Test Example 3.

FIG. 10 is a diagram for explaining a state in which sludge adheres to an inner surface of a tubular filtration membrane when wastewater is caused to flow by a cross flow method and a total volume filtration method.

FIG. 11 is a diagram for explaining an operation of peeling off tubular sludge that has adhered and accumulated on the inner surface of the tubular filtration membrane and extruding it from the end portion in the axial direction.

FIG. 12 is a flow chart for explaining a water treatment method performed using a conventional membrane filtration device.

[Explanation of symbols]

4: Reaction tank, 7: Coagulation tank, 11: Filtration membrane device, 12: Circulation return line, 14: Permeate water line, 17: Backwash water inlet line, 20: Sludge drawing line, 92: Water supply line.

Claims (8)

[Claims] 1. A raw water containing a turbidity component is caused to flow through a tube of a tubular filtration membrane, and while the turbidity component contained in the raw water is deposited on the inner peripheral surface of the membrane, permeated water is passed to the outside in the radial direction of the membrane. A treatment method for performing a filtering operation for flowing out, and a washing operation for interrupting this filtering operation to remove the suspended components adhering and deposited on the inner peripheral surface of the tubular filtration membrane from the inner peripheral surface of the membrane, wherein: The washing operation is performed so that the tubular body made of a suspended component adhered and deposited in a tubular shape on the inner peripheral surface of the tubular filtration membrane is separated from the membrane surface without substantially destroying the tubular shape. The peeling operation of flowing backwash water from the outer side to the inner side of the tube, and the tubular body of the suspended component peeled from the membrane surface by this peeling operation is performed by flowing water in the axial direction of the tubular filtration membrane from the pipe end. A method for treating water containing a turbid component, which comprises performing an extrusion operation. 2. The water containing a turbid component is characterized in that the filtration operation in claim 1 is a process in which raw water containing a turbid component at a high turbidity is flowed through a tubular filtration membrane in a cross-flow method. Processing method. 3. The filtration operation according to claim 1, wherein raw water containing a turbidity component at a low turbidity is passed through a tubular filtration membrane by a total volume filtration method. Processing method. 4. The method according to any one of claims 1 to 3,
Among the washing operations for removing the tubular body composed of the suspended component adhered and deposited on the inner surface of the tubular filtration membrane, the operation of axially pushing the tubular body from the tube end portion of the tubular filtration membrane is A method for treating water containing turbidity components, characterized in that extruded water is caused to flow downward in a tube of a tubular filtration membrane installed in a mold to extrude the tubular body downward. 5. A tubular filtration membrane provided so that raw water containing a turbid component flows axially in the tube, and the raw water is caused to flow in the tube of the tubular filtration membrane from the peripheral surface of the membrane to the outside in the radial direction of the membrane. Raw water passage means for performing the outflow of permeated water and the filtration of turbidity components, and the radial direction of the tubular filtration membrane in order to separate the cylindrical body of turbidity components deposited and deposited on the inner peripheral surface of the membrane from the membrane surface. Exfoliating water flow means for flowing backwash water from the outside to the inside, and extruded water flow means for extruding the cylindrical body of suspended matter separated from the membrane surface with running water in the axial direction of the tubular filtration membrane, and the raw water. A turbidity component characterized by comprising: a water flow control means for intermittently interrupting the water flow by the water flow means, and carrying out the water flow by the peeling water water flow means and the extrusion water water flow means in order. Including water treatment equipment. 6. The method according to claim 5, further comprising a tank for settling a tubular body made of a turbid component extruded from the tubular filtration membrane at the bottom, and the tubular body of the settled turbid component is externally supplied from a lower portion of the tank. A treatment device for water containing turbidity components, characterized in that it is provided with a means for extracting the water. 7. The tubular filtration membrane according to claim 5, wherein a tubular filtration membrane through which raw water is circulated is installed vertically in the filtration tower, and the extruded water flow means is a tubular body of the exfoliated suspended component. It was installed so that the extruded water would pass through in a downward flow so that it would be extruded downward from the inside of the filter membrane tube, and at the bottom of the filtration tower, a tubular body of turbid components extruded downward from the tubular filtration membrane and settled out. A treatment device for water containing turbidity components, characterized in that means for extracting the water to the outside of the filtration tower is provided. 8. The dehydrated tubular body according to claim 6 or 7, which is extracted by a means for extracting the sedimented tubular body of turbidity components to the outside of a tank or a filtration tower without using a concentrating means. A treatment device for water containing suspended matter, characterized by being provided so as to be sent to a means.