JP3514187B2 - Filtration device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a suspended substance (SS) concentration of 500 mg / L, which is represented by activated sludge and coagulated sludge.
The above suspensions are MF (microfiltration) membranes and UF (ultrafiltration)
The present invention relates to a filtration device suitable for filtration using a membrane or a non-woven fabric, and more particularly, to improvement of chemical cleaning equipment of an immersion type filtration device of a type in which a filter is immersed in a water tank containing a liquid to be treated for filtration.

[0002]

2. Description of the Related Art Conventionally, as a method for directly filtering raw water containing a high concentration of suspended substances, it is known that it is effective to immerse a filter body in a water tank and carry out filtration by an external pressure system.
According to this method, since the flow path of the liquid to be filtered in the tank can be widened, the liquid to be filtered is concentrated into a gel or cake, and the liquid to be filtered or the filtration surface is filtered. This is because the problem of blocking the

FIG. 2 is a sectional view showing an immersion tank of a conventional immersion type filtration device. In FIG. 2, 1 is an immersion tank,
Filter body modules 3A and 3B provided with partition plates 2A and 2B having upper and lower openings on both sides are immersed in the center. The partition plates 2A and 2B are for aerating only the inside of the partition plate 2A, 2B with a blower (not shown) by the aeration pipe 4 provided in the lower portion of the filter body module 3B, and promoting the upward flow due to the aeration. An overflow port 5 is for overflowing the excess concentrated liquid to be filtered.

Raw water is supplied to the immersion tank 1 through a pipe 6, and filtered water (permeated water) is taken out through a pipe 7 as treated water. Reference numeral 8 is a pipe for extracting the liquid in the tank, and 9 is a pipe for supplying the chemical liquid.

In such a submerged filtration device, an MF membrane or a UF membrane is usually used as the filtration membrane when the membrane module is used as the filtration body modules 3A and 3B.
In particular, an external pressure type hollow fiber membrane or flat membrane of MF membrane is preferably used.

In the filtration process, the liquid to be filtered in the dipping tank 1 is aerated or stirred by a stirring means to suppress the concentration of the substance to be filtered (SS) on the membrane surface and reduce clogging of the filter body. To do. In this case, as shown in FIG. 2, partition plates 2A and
2B is provided and only the lower parts of the filter body modules 3A, 3B inside the partition plates 2A, 2B are aerated, so that the partition plate 2
A method of causing an ascending flow due to an air lift in A and 2B is often adopted.

When the filtration treatment is carried out in such a manner, the so-called cross-flow flux of the liquid to be filtered cannot be made high. Therefore, in order to prevent clogging of the filter body, the filtration flux is 1 m ³ / m ² / It is set below day. Further, in order to prevent the liquid flow path of the liquid to be filtered from being blocked, it is necessary to make the distance between the filter bodies relatively large. Therefore, this results in
The filter body module requires a relatively large occupied area, and the immersion tank also has a relatively large capacity. For example, treated water 10
In order to obtain 0 m ³ / day, the volume of the dipping tank 1 is usually required to be about 10 to 50 m ³ .

By the way, in such an immersion type solid-liquid separation device, it is necessary to wash the filter body to remove SS and the like adhering to the surface of the filter body, but as described above, the filter module 3A, Since the occupying area of 3B is large and the immersion tank 1 has a large capacity, the inflow of raw water is stopped and the liquid to be filtered in the immersion tank 1 is drawn out of the tank through the pipe 8 for chemical cleaning of the filter body. After that, a method has been proposed in which a cleaning chemical is introduced into the immersion tank 1 through the pipe 9 to perform chemical cleaning while the filter body is installed in the immersion tank 1.

Since it is desired to continue the filtration treatment during the chemical cleaning as described above, generally, the dipping tanks are constructed by being divided into a plurality of parallel series, and the chemical cleaning is performed for each tank.
It is considered that a method of continuing the filtration treatment in another dipping tank while the one tank is being chemically cleaned is preferable. In this case, the amount of treated water corresponding to the chemical cleaning series decreases, so the amount of permeated water in other dipping tanks that continue filtration treatment may be temporarily increased as necessary to increase the amount of treated water. May be done.

Conventionally, as a chemical cleaning method for the immersion tank, a method of performing the following steps (1) to (4) has been proposed.

The introduction of raw water into the immersion tank is stopped, the liquid to be filtered is withdrawn from the immersion tank, and the inside of the immersion tank is emptied.

The extracted liquid to be filtered may be returned to the raw water tank,
Treat as waste water, temporarily evacuate to another storage tank, or supply to another immersion tank. When the liquid to be filtered is activated sludge and the upstream of the immersion tank is the activated sludge treatment tank, the activated sludge in the tank may be received in the activated sludge treatment tank in the preceding stage.

The cleaning solution is supplied into the dipping tank, and the filter body is cleaned by contacting the cleaning solution for a certain period of time. Prior to the supply of the cleaning chemical liquid, a rinse step may be added in which fresh water is charged into the dipping tank and the tank liquid is extracted again. Here, as a method of supplying the cleaning chemicals to the immersion tank, 1) a method of separately supplying clean water such as tap water, industrial water or treated water and an active ingredient (chemical) to the immersion tank and mixing them in the immersion tank 2) There is a method in which fresh water and an active ingredient are mixed in another water tank in advance to prepare a cleaning chemical solution, and the cleaning chemical solution is transferred to an immersion tank, or a combination thereof.

As the active ingredient of the cleaning chemical solution, an alkali such as caustic soda, an oxidizing agent such as sodium hypochlorite, an acid such as sulfuric acid, and a combination thereof are used. Sodium hypochlorite is added to 100% caustic soda solution to obtain an effective chlorine concentration of 100 to 1000 m.
In many cases, a liquid having a pH of 12 or more and a g / L is used. As the acidic chemical solution, hydrochloric acid or sulfuric acid having a pH of 2 or less at about 0.1 to 2% by weight is often used.

While the filter and the chemical solution are in contact with each other, a stirring flow is applied to the filter surface mainly by aerating from the lower part of the filter to decompose, dissolve or remove contaminants on the filter surface. This contact time is usually about 1 to 24 hours and is usually selected according to the concentration of the chemical solution and the degree of contamination of the filtration surface.

After the washing time has elapsed, the chemical solution in the dipping tank is extracted, and if necessary, fresh water is added, and after a rinse step of extracting the solution in the tank again, raw water (liquid to be filtered) is added and filtration is performed. Resume.

The chemical solution extracted from the dipping tank is stored in a chemical solution storage tank and repeatedly used several times while supplementing the active ingredient as necessary, or is directly treated as waste water. The chemical solution may be neutralized to some extent in the dipping tank before being taken out. When storing the used chemicals,
It is repeatedly used about 3 to 6 times, and after the stain of the chemical liquid becomes remarkable or the cleaning effect of the chemical liquid deteriorates, it is neutralized if necessary and treated as waste water.

[0018]

However, when the dipping tanks are constructed by dividing them into a plurality of parallel series in order to continue the membrane filtration treatment even during the chemical cleaning, there are the following problems.

(Problem 1) If each tank is equipped with a tank liquid withdrawal pump, a chemical injection pump, a chemical solution dilution adjustment fresh water supply pipe, etc., which are necessary for chemical cleaning work,
Construction costs are high due to the need to install these devices.

(Problem 2) Transfer of the liquid to be filtered in the dipping tank,
Since it takes a long time to put in or take out the chemical liquid, the work efficiency is poor and the chemical cleaning requires a long time. Although it is possible to shorten the transfer time by increasing the size of the pump used for transferring these liquids, in this case, the cost of the pump increases and it is not economical.

(Problem 3) When the neutralization work for discarding the cleaning chemical solution for the filter is carried out in each dipping tank, the pH of each dipping tank is increased.
Since a meter for detecting the neutralization of the meter and the equipment for supplying the neutralizing agent are required, the cost of the meter, the cost of piping, the cost of instrumentation of the electric machine are increased, and the operation becomes complicated. It is easy to make mistakes. In order to avoid this problem, if the cleaning chemical is once transferred to a water tank other than the immersion tank and neutralized in this water tank, a complete set of neutralization equipment is sufficient. The stirring equipment is required, which also causes a cost increase. Also, in the neutralization work,
Since the number of steps for temporarily transferring the cleaning chemical solution to the neutralization water tank increases, the steps become complicated and the time until the end of the cleaning step also increases.

When the active ingredient is consumed while the filter body and the chemical solution are in contact with each other, it may be better to supplement the active ingredient at any time. For example, when the filter used to filter the activated sludge is washed with a chemical solution containing sodium hypochlorite, the effective chlorine concentration decreases during the washing. It is effective to measure and to add sodium hypochlorite. However, in order to do this, it is necessary to provide a means for replenishing sodium hypochlorite at least in each membrane dipping tank, which increases the number of pipes, valves, pumps, etc., and increases construction costs. It may be possible to place sodium hypochlorite in a water tank as needed using flexible piping such as a hose, but in this case the work becomes complicated and the chemical cleaning operation is fully automatic. Can't do it.

(Problem 4) When the liquid to be filtered is extracted from the immersion tank for chemical cleaning, the liquid to be filtered remains in the lower part of the immersion tank for about several tens of mm. If the cleaning chemical liquid is added while the liquid to be filtered remains, the following problems will occur. This problem becomes remarkable especially when the chemical solution is repeatedly used several times. (4-1) The remaining organic matter in the liquid to be filtered, particularly the microorganisms, is dissolved in the chemical liquid, so that the liquid becomes very easily foamable. (4-2) The remaining organic substances, particularly microorganisms, in the liquid to be filtered react with the active ingredients, particularly effective chlorine, in the cleaning chemicals, the active ingredients are consumed, and the cleaning effect on the filter becomes weak.

Similarly, after the cleaning process is completed, when the cleaning chemical solution is taken out from the immersion tank, the cleaning chemical solution is several tens mm below the immersion tank.
It remains to some extent. In this way, if the liquid to be filtered is added while the cleaning chemical liquid remains and the filtration process is restarted, the following problems occur. (4-3) By mixing the cleaning chemical liquid and the liquid to be filtered, a part of the liquid to be filtered is dissolved, and the quality of treated water, particularly COD and chromaticity are deteriorated. This phenomenon is particularly remarkable when the cleaning liquid is an alkaline liquid because the organic substances mainly containing microorganisms in the liquid to be filtered are dissolved. (4-4) When the cleaning chemical solution is an acid or an alkaline solution, the pH of the introduced liquid to be filtered becomes acidic or alkaline due to the residual cleaning chemical solution, and the quality of treated water deteriorates. Further, when the liquid to be filtered is activated sludge, the activity of the sludge is deactivated, and the quality of the treated water deteriorates due to the elution of organic substances, nitrogen, and phosphorus from the sludge. When the liquid to be filtered is coagulated sludge,
The aggregated phosphorus, COD, and chromaticity are eluted, and the iron ions and aluminum ions used as the aggregating agent are dissolved to contaminate the filter body and deteriorate the treated water quality.

As described above, the problems of (4-1) and (4-2) are as described above, in which fresh water is added to the immersion tank before the cleaning chemical is added after the liquid to be filtered is extracted from the immersion tank. It is possible to reduce or solve the problem by diluting the remaining liquid to be filtered, and then performing a so-called rinsing step of extracting it again, and then adding a chemical liquid. It is necessary to install piping equipment for supply, which increases equipment costs. In particular, when the injection of fresh water is automatically performed using the automatic valve, the cost of the automatic valve and the cost of the electric instrumentation also increase.

The problems (4-3) and (4-4) are also solved by performing the above-described rinsing step before extracting the liquid to be filtered after extracting the chemical liquid from the dipping tank. Since it is possible to reduce the concentration of the chemical solution remaining inside, it can be reduced or solved, but this also leads to an increase in costs of piping, automatic valves, electric instrumentation, and the like.

(Problem 5) During chemical cleaning of the filter,
As described above, it is effective to perform aeration from the lower part of the filter to remove contaminants on the filter surface, but at this time, the cleaning chemical solution often foams violently. When the cleaning chemical liquid foams in this way, it contaminates the surroundings and makes it unattractive, and
Since the cleaning chemicals are scattered around, the working environment is significantly deteriorated.

In order to prevent this, it is necessary to add an antifoaming agent. For that purpose, it is necessary to provide an antifoaming agent injection pipe in each dipping tank and attach a valve for switching the injection destination. , The piping cost will increase. In particular, in order to automatically switch the pouring position so that the dipping tank to which the defoaming agent is added becomes the dipping tank currently being washed, an automatic valve or defoaming agent injection pump is installed according to the number of dipping tanks. Therefore, the cost of automatic valves, chemical pumps, and electrical instrumentation increases.

As described above, in the filtering apparatus constructed by dividing the dipping tanks into a plurality of parallel lines, the liquid to be filtered and the cleaning chemical liquid are exchanged for each dipping tank to perform the chemical cleaning, so that one dipping tank can perform the chemical cleaning. You can continue the filtration process with other filtration equipment;
Although it has the advantage of being able to reduce the storage tank for cleaning chemicals and the evacuation tank for the liquid to be filtered during cleaning, it requires multiple chemical cleaning pumps and piping, multiple automatic valves, multiple chemical injection pumps, etc. There are drawbacks that the cost and instrumentation cost increase, and that the device becomes complicated and an operation error is likely to occur.

The present invention solves the above-mentioned conventional problems, and in a filtering device constructed by dividing the immersion tank into a plurality of parallel series, the pump, piping and instruments necessary for chemical cleaning are reduced to reduce the equipment cost. It is an object of the present invention to provide a filtration device which is capable of easily and efficiently cleaning chemicals in a short time while simplifying the equipment and equipment while reducing the above.

[0031]

A filter device according to the present invention comprises a plurality of containers each having a filter therein, and a container for supplying liquid to each container and discharging liquid from each container.
A filtration device having a cleaning pump for a table, wherein the inside of each container communicates with the suction side of the cleaning pump via a liquid extraction pipe, and the discharge of the cleaning pump via a liquid supply pipe. The liquid take-out pipe is provided with a liquid take-out valve, and each liquid supply pipe is provided with a liquid supply valve. It is characterized in that a means for supplying a body cleaning chemical solution is connected.

With this filtration device, one cleaning pump is used to transfer the liquid for chemical cleaning of all the immersion tanks, that is, to take out the liquid to be filtered from the immersion tanks and to wash the cleaning chemicals into the immersion tanks. Can be supplied, cleaning chemicals can be taken out from the dipping tank, and only two pipes are required for each dipping tank, which greatly reduces the equipment cost and simplifies the equipment. It can be operated easily.

If at least one storage tank is further installed, and the inside of this storage tank is communicated with the suction side of the cleaning pump through a liquid supply pipe having a liquid supply valve, this storage tank is provided. By using as the cleaning chemical solution storage tank, the cleaning chemical solution can be supplied from this storage tank to the immersion tank. Further, in this case, in the case of the filtering device according to claim 3, wherein the storage tank is connected to the discharge side of the cleaning pump via the return pipe having the return valve, the cleaning chemical solution is again supplied to the storage tank after the chemical cleaning. Can be returned. Further, by making this storage tank a filtered liquid storage tank, the filtered liquid in the dipping tank during chemical cleaning can be evacuated to this storage tank, and after the chemical cleaning, the filtered liquid can be returned to the dipping tank again. .

In the filtration device according to claim 4, which is provided with means for communicating the discharge side of the cleaning pump with the wastewater treatment device, the filtered liquid or the cleaning waste liquid in the dipping tank for chemical cleaning is treated with this wastewater treatment device. It can be transferred to the device.

According to the filtration device of claim 5, wherein at least one sensor for detecting the water quality is provided on the discharge side and / or the suction side of the cleaning pump, the water quality of chemical cleaning can be controlled. Further, in the case of the filtration device according to claim 6, further comprising means for supplying a neutralizing agent for the cleaning chemical liquid to the discharge side or the suction side of the cleaning pump, the neutralization treatment of the cleaning chemical liquid after use can be performed.

In the filtration device according to claim 7, wherein the discharge side or suction side of the cleaning pump is provided with means for supplying fresh water or low turbidity water, the rinse step before and after chemical cleaning is performed by supplying such water. Can be carried out. In addition, clean water, tap water, industrial water, treated water of the filtration device or treated water of other water treatment equipment can be used, and as the low turbidity water, water having an SS concentration of 500 mg / L or less can be used. Can be used.

According to the filtration device of claim 8, wherein a means for supplying an antifoaming agent is provided on the discharge side or the suction side of the cleaning pump.
The defoaming agent can be supplied to the immersion tank during chemical cleaning.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a filtration device of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of the membrane filtration device of the present invention. In FIG. 1, members having the same functions as those shown in FIG. 2 are designated by the same reference numerals.

In FIG. 1, reference numerals 10 and 20 denote membrane dipping tanks. The construction of these membrane dipping tanks 10 and 20 is that a recess is provided as a liquid reservoir 10M or 20M at one corner of the tank bottom. Has the same structure as the general immersion tank 1 shown in FIG. The filter module 3A, 3
As B, a membrane module is provided.

Reference numerals 30 and 40 are sludge evacuation tanks and chemical liquid storage tanks, which are provided with an aeration pipe 4 similarly to the membrane dipping tanks 10 and 20, and liquid reservoirs 30M and 40M are provided at one corner of the bottom respectively.
Equipped with. P is a cleaning pump.

In the membrane dipping tanks 10, 20, the sludge evacuation tank 30, and the chemical liquid storage tank 40, liquid extraction pipes 10A, 2 are provided, respectively.
0A, 30A, 40A and liquid supply pipes 10B, 20B, 3
0B and 40B are provided, and the liquid take-out pipe 10A,
20A, 30A, and 40A are liquid take-out valves (hereinafter, simply referred to as valves) V _1A , V _2A , V _3A , and V _4A.
Through the suction side of the cleaning pump P. Further, the liquid supply pipes 10B, 20B, 30B and 40B are respectively liquid supply valves (hereinafter simply referred to as valves) V _1B and V.
It is connected to the discharge side of the cleaning pump P via _2B , V _3B and V _4B . The liquid take-out pipes 10A, 20A, 30
Each of A and 40A is provided so that its tip end opening is located near the bottom surface of the liquid reservoirs 10M, 20M, 30M and 40M of each tank.

Raw water is supplied to the membrane dipping tanks 10 and 20 through pipes 6A and 6B branched from the raw water supply main pipe 6, respectively, and treated water is taken out from a membrane filtrate (permeate) take-out pipe (not shown). Is configured. Valves V _6A and V _6B are provided on the raw water supply pipes 6A and 6B, respectively.

Further, the chemical liquid storage tank 40 is provided with a chemical liquid supply pipe 40C and an industrial water supply pipe 40D for directly supplying an effective component of the chemical liquid (for example, 25 wt% caustic soda solution) from a tank truck or the like. There is. The pipe 40D is equipped with a valve V _4D .

A treated water supply pipe 11 from a treated water storage tank is further connected to the suction side of the cleaning pump P via a valve V ₁₁ .

On the discharge side of the cleaning pump P,
Piping 1 for supplying liquid to the raw water tank and the aeration tank, respectively
2 and 13 are connected via valves V ₁₂ and V ₁₃ , respectively.

A pH meter S, a supply pipe 14 for the chemical liquid 1, a supply pipe 15 for the chemical liquid 2, a supply pipe 16 for the industrial water, and a supply pipe 1 for the defoaming agent 1 are provided between these valves and the cleaning pump P.
7, supply pipe 18 for neutralizer 1 and supply pipe 19 for neutralizer 2
Is provided. The industrial water supply pipe 16 is provided with a valve V ₁₆ .

A check valve (check valve) V for preventing backflow is provided at necessary locations such as the supply pipe and the discharge side of the cleaning pump P.

According to this membrane filtration device, a series of operations for chemical cleaning of the membrane dipping tanks 10 and 20 can be efficiently performed by one cleaning pump P by switching valves. it can.

[Example of Transfer Operation of Liquid to Be Filtered Prior to Chemical Cleaning] For example, to transfer the liquid to be filtered in the tank to the sludge evacuation tank 30 prior to cleaning the chemical in the membrane dipping tank 10, a valve V is used.
Only _1A and V _3B are opened to operate the cleaning pump P, and the liquid to be filtered in the membrane dipping tank 10 is extracted from the liquid extraction pipe 10A and transferred to the sludge evacuation tank 30 from the liquid supply pipe 30B.
The destination of the filtered liquid may be the membrane dipping tank 20,
In this case, only the valves V _1A and V _2B are opened, and the liquid to be filtered in the membrane dipping tank 10 extracted from the liquid withdrawing pipe 10A is transferred to the membrane dipping tank 20 from the liquid supply pipe 20B by the cleaning pump P. . When the liquid to be filtered is returned to the raw water tank or the aeration tank, the valve V _1A and the valve V ₁₂ or the valve V _{13 are used.}
And the cleaning pump P is used to open the liquid extraction pipe 10
The liquid to be filtered in the membrane dipping tank 10 extracted from A is piped 12
Or it is returned to the raw water tank or aeration tank via 13. The liquid to be filtered in the membrane dipping tank 20 can be similarly transferred.

[Example of Rinse Operation Before and After Chemical Cleaning] For example,
In the rinsing process of the membrane immersion tank 10, according to the transfer operation example described above, after the tank liquid (liquid to be filtered or cleaning chemical liquid) is extracted, only valves V _1B and V ₁₆ are opened to supply a predetermined amount of industrial water. Supply from the pipe 10B, and then switch the valves to open only the valve V _1A and the valves V _2B , V _3B , V ₁₂ or V ₁₃ and operate the cleaning pump P to take out the water in the membrane immersion tank 10. Extracted from the pipe 10A and fed to the membrane immersion tank 20 from the liquid supply pipe 20B, fed to the sludge evacuation tank 30 from the liquid supply pipe 30B, or returned to the raw water tank or aeration tank from the pipe 12 or 13. . The rinsing step of the membrane immersion tank 20 can be similarly performed by opening the valves V _2A and V _2B instead of the valves V _1A and V _1B .

[Example of Neutralizing Cleaning Chemical Solution] When the cleaning chemical solution contained in the membrane dipping tank 10 is neutralized, the valve V _{1A is used.}
And V _1B are opened, and the other valves are closed, and the cleaning chemical solution in the membrane dipping tank 10 is internally circulated by the cleaning pump P in the liquid take-out pipe 10A and the liquid supply pipe 10B to stir the liquid in the tank. At the same time, the neutralizing agent 1 or the neutralizing agent 2 (for example, acid such as sulfuric acid, alkali such as caustic soda, reducing agent such as sodium bisulfite) is injected into the system from the discharge side of the cleaning pump P (at this time). The injection control of the neutralizing agent is performed based on the measurement result of the pH meter S.). The neutralization of the cleaning chemical in the chemical storage tank 40 can be performed in the same manner by opening only the valves V _4A and V _4B .

According to the above neutralization operation, it is not necessary to newly provide a stirring means for neutralization in the chemical liquid storage tank 40 or the like, and the cost can be reduced.

In particular, as shown in FIG. 1, by providing a pH meter and a means for supplying a neutralizing agent, it is possible to share the equipment for neutralizing treatment for all the water tanks, and the cost of the measuring instrument, the piping cost,
Electric equipment instrumentation cost can be saved and the cost can be reduced rationally. In addition, automatic control can be performed, operation can be simplified, operation mistakes can be prevented, and the total time required for the chemical solution process can be shortened. You can

[Example of Preparation of Cleaning Chemical Solution] When a large amount of cleaning chemical solution is initially prepared in the chemical solution storage tank 40, a predetermined amount of chemical solution is introduced into the chemical solution storage tank 40 from the chemical solution supply pipe 40C and a valve is provided. _V4D is opened and industrial water is added to prepare a chemical solution having a predetermined concentration. To prepare this chemical solution, the valve V _4B is opened, and the chemical solution 1 or 2 is supplied from the piping 14 or 15 to the chemical solution storage tank 40 through the solution supply pipe 40B.
It can also be carried out by supplying industrial water from 6 and diluting it. In preparing this chemical solution, the valves V _4A and V _4B are opened, and the chemical solution in the chemical solution storage tank 40 is circulated by the cleaning pump P through the solution take-out pipe 40A and the solution supply pipe 40B to stir the chemical solution. Therefore, it is not necessary to provide a dedicated stirrer in the chemical solution storage tank.

[Example of chemical cleaning operation] For example, the chemical liquid storage tank 4
When the membrane dipping tank 10 is chemically washed with the cleaning chemical liquid in 0, the liquid to be filtered in the membrane dipping tank 10 is extracted in advance and transferred to a predetermined location, and after a rinse step as necessary, the valve is Only V _4A and V _1B are opened, the cleaning pump P is operated, and the cleaning chemical solution in the chemical solution storage tank 40 is taken out of the liquid extraction pipe 40A.
It is further extracted and fed to the membrane immersion tank 10 via the liquid supply pipe 10B. This chemical cleaning is performed by using the chemical solution 1 from the pipe 14 or 15.
Alternatively, the chemical solution 2 may be supplied to the membrane dipping tank 10 and the working water may be introduced into the membrane dipping tank 16 through the pipe 16 to directly prepare the cleaning chemical solution in the membrane dipping tank 10 for execution. Further, for example, when the chemical cleaning of the membrane immersion tank 20 is completed immediately before the chemical cleaning of the membrane immersion tank 10, the valve V _2A and the valve V _{1B are used.}
The cleaning chemical solution in the membrane dipping tank 20 may be extracted from the liquid take-out pipe 20A by the cleaning pump P and sent to the membrane dipping tank 10 via the liquid supply pipe 10B.

[Example of Replenishing Operation of Active Ingredient during Chemical Cleaning] For example, when the membrane dipping tank 10 is being chemically cleaned, the valve V _{1B is used.}
Only the opening is opened and the chemical solution 1 or the chemical solution 2 is supplied from the solution supply pipe 10B to supplement the cleaning chemical solution in the membrane immersion tank 10 with the active ingredient. The replenishment of this active ingredient can be performed for all aquariums by switching the valve.

When the replenishment of the chemical liquid 1 or the chemical liquid 2 is small, the chemical liquid remaining in the liquid supply pipe 10B is wasted. In this case, for example, only the valves V _1A and V _1B are opened. As a result, the cleaning pump P is operated to inject the chemical liquid 1 or the chemical liquid 2 while circulating the liquid in the membrane immersion tank 10 through the liquid take-out pipe 10A and the liquid supply pipe 10B, or the valve V _1B.
It is also possible to open only the valve and inject a required amount of the chemical liquid, and then open the industrial water injection valve V ₁₆ to push out the chemical liquid remaining in the liquid supply pipe 10B or the like.

[Example of Injecting Defoaming Agent] For example, when injecting the defoaming agent into the membrane dipping tank 10, only the valve V _1B is opened and the defoaming agent is passed through the liquid supply pipe 10B. Supply to. The defoaming agent can be injected into the membrane dipping tank 20 by opening the valve V _2B .

The defoaming agent is usually injected in a very small amount. Therefore, in order to prevent the defoaming agent remaining in the liquid supply pipe 10B and the like from being wasted, only the valves V _1A and V _1B are opened and the cleaning pump P is operated to remove the liquid in the membrane dipping tank 10 from the liquid take-out pipe. The antifoaming agent is injected while circulating 10A and the liquid supply pipe 10B, or in FIG. 1, the injection position of the antifoaming agent on the discharge side of the cleaning pump P and the injection position of the working water are exchanged, and the valve V is used. _It is also possible to open only _1B and inject a required amount of the defoaming agent, and then open the industrial water injection valve V ₁₆ to push out the defoaming agent remaining in the liquid supply pipe 10B or the like.

[Example of Transfer of Cleaning Chemical Solution After Chemical Cleaning] For example, after cleaning the chemical in the membrane dipping tank 10, to transfer the cleaning chemical in the tank to the chemical solution storage tank 40, only the valves V _1A and V _4B are used. Is opened and the cleaning pump P is operated, and the cleaning chemical solution in the membrane dipping tank 10 is extracted from the liquid extraction pipe 10A and transferred to the chemical liquid storage tank 40 from the liquid supply pipe 40B. The transfer destination of the cleaning chemical liquid may be the membrane immersion tank 20 in which the chemical cleaning is performed next. In this case, only the valves V _1A and V _2B are opened and the cleaning pump P is used to extract the liquid from the liquid extraction pipe 10A. The liquid to be filtered is transferred in advance to the cleaning chemical liquid in the membrane dipping tank 10 and, if necessary, is transferred from the liquid supply pipe 20B to the membrane dipping tank 20 that has undergone the rinsing step.

When the cleaning chemical is neutralized by the neutralization operation described later and then returned to the raw water tank or the aeration tank, the valve V _1A and the valve V ₁₂ or the valve V ₁₃ are opened and the cleaning pump P is opened.
The membrane dipping tank 1 extracted from the liquid extraction pipe 10A by
The neutralization treatment liquid in 0 is returned to the raw water tank or the aeration tank via the pipe 12 or 13. The cleaning chemical solution in the membrane immersion tank 20 can be transferred in the same manner.

[Example of Resuming Operation of Membrane Filtration Treatment After Completion of Chemical Cleaning Step] After completion of the chemical cleaning step (that is, after performing chemical cleaning, extracting cleaning chemical solution, and optionally rinsing step), for example, sludge When the liquid to be filtered in the evacuation tank 30 is transferred to the membrane dipping tank 10 and the membrane filtration process is restarted, the valves V _3A and V _1B are opened, the cleaning pump P is operated, and the sludge evacuation tank 30 is opened. The liquid to be filtered in the liquid extraction pipe 30A
It is further extracted and supplied to the membrane immersion tank 10 through the liquid supply pipe 10B, and the membrane filtration process is restarted. When the liquid to be filtered in the membrane dipping tank 20 is transferred to the membrane dipping tank 10 to restart the membrane filtration process in the membrane dipping tank 10 and to wash the membrane dipping tank 20 with a chemical, the valves V _2A and V _{1B are used.} Open to open cleaning pump P
To remove the liquid to be filtered in the membrane dipping tank 20
The liquid is withdrawn from A and supplied to the membrane dipping tank 10 through a liquid supply pipe 10B. Alternatively, when there is no liquid to be filtered on standby, the valve V _6A is opened and the raw water supply pipes 6 and 6A are used to feed the membrane dipping tank 1
The introduction of raw water to 0 is restarted and the membrane filtration process is started.

According to the membrane filtration apparatus of the present invention, by combining the above operations, it is possible to carry out a rational chemical cleaning step by the following method, which greatly reduces the cleaning time and the number of operations. Can be reduced.

[Example 1 of rationalized chemical cleaning process] For example, when the membrane dipping tank 10 is undergoing chemical cleaning, the time until the cleaning is completed is used to perform the next chemical cleaning. The liquid to be filtered in 20 is extracted, and the rinsing step is also terminated if necessary. Then, after the chemical cleaning of the membrane immersion tank 10 is completed, the cleaning chemical solution in the membrane immersion tank 10 is directly transferred to the membrane immersion tank 20. If necessary, the active ingredient is replenished during this transfer.

After completion of the transfer, the membrane dipping tank 10 is subjected to a rinsing step if necessary, and then the liquid to be filtered is added to restart the membrane filtration process.

[Example of rationalized chemical cleaning step-2] After the chemical cleaning of the membrane dipping tank 10 is completed, the cleaning chemical solution in the membrane dipping tank 10 is extracted, and a rinse step is performed if necessary, and then the chemical cleaning is performed. The liquid to be filtered in the membrane dipping tank 20 for performing is directly put into the membrane dipping tank 10. After completion of the charging, the membrane dipping tank 10 restarts the membrane filtration process, and the membrane dipping tank 20 undergoes a rinsing step if necessary, and then a cleaning chemical is added to start chemical cleaning.

Both the above-mentioned chemical cleaning process examples-1 and -2 can be carried out only by switching the valve.
By directly transferring the liquid to be filtered or the cleaning chemical liquid between the membrane and the membrane dipping tank 20, a storage tank or the like during the transfer of the liquid can be eliminated, and the time required for chemical cleaning can be shortened. , The number of work can be reduced.

In the above-mentioned chemical cleaning step examples-1 and -2, although the membrane dipping tank 10 and the membrane dipping tank 20 temporarily stopped the membrane filtration treatment at the same time, the treated water could not be sampled. Since the time is a short time of about 1 hour, there is almost no problem, and in particular, by performing such switching during a time period when the amount of inflow of raw water is small or a time period when the amount of treated water is large, it is practical The influence can be almost eliminated.

In this membrane filtration device, a self-priming pump is used as the cleaning pump according to the purpose, and a pump having resistance to the chemicals used is appropriately selected.

In particular, it is desirable that the cleaning pump is automatically stopped when the transfer of a predetermined amount of liquid is completed. Further, each water tank is provided with a level switch (water level meter) to complete the withdrawal and addition of the liquid in the tank. It is desirable to detect these and perform these automatically.

The valve may be an automatic valve or a manual valve, but it is desirable that part or all of the valve is an automatic valve and at least a part of opening and closing of the valve necessary for the chemical cleaning operation is automated. .

The membrane filtration apparatus shown in FIG. 1 is an example of the embodiment of the present invention, and the present invention is not limited to the illustrated apparatus unless it exceeds the gist of the invention.

The water quality detecting sensor is not limited to a pH meter, but may be an ORP meter or the like, and two or more of these may be installed. Further, the installation location may be not only on the discharge side of the cleaning pump P but also on the suction side.

Although two membrane dipping tanks are provided in FIG. 1, the number of membrane dipping tanks may be three or more, and generally about 3 to 6 tanks are installed.

In FIG. 1, each of the membrane dipping tanks 10, 20, the sludge evacuation tank 30, and the chemical liquid storage tank 40 is provided with a liquid reservoir 10M to 40M at one corner of the bottom surface, and each liquid reservoir 10M to. The opening tips of the liquid take-out pipes 10A to 40A are provided in the vicinity of the bottom surface of the 40M, respectively. By providing the liquid pool portion in this way and inserting the tip of the liquid take-out pipe into the inside, respectively, When removing the liquid from the tank, the amount of residual liquid in the tank can be made extremely small, which prevents deterioration of the quality of treated water due to residual cleaning chemicals and deterioration of chemical cleaning effect due to residual liquid to be filtered. ,preferable.

The raw water supply pipes 6, 6A, 6B have valves V _6A ,
The raw water may be supplied and stopped by opening and closing V _6B , or the raw water may be supplied and stopped by operating and stopping the raw water supply pump.

The overflow port 5 of the membrane dipping tanks 10 and 20 allows the concentrated excess liquid to be filtered to flow out when the liquid to be filtered is excessively supplied to the membrane dipping tanks 10 and 20, and the raw water tank. Or to return to the aeration tank to prevent concentration of the substance to be filtered in the membrane dipping tanks 10 and 20.

Further, in FIG. 1, the chemical solution, the working water, the defoaming agent, and the neutralizing agent are introduced to the discharge side of the cleaning pump P, but these are the suction side of the cleaning pump P. May be introduced in. Generally, in order to supply water with pressure such as tap water or industrial water, it is sufficient to use the discharge side of the cleaning pump, and the water that needs to be sucked up from a tank such as a treated water storage tank is the supply side of the cleaning pump. Need to be plumbed to. Supply pipes for each of these chemicals and the like are not always required, but by providing these on the suction side or the discharge side of the cleaning pump, as in the above-mentioned operation side,
Can perform more efficient chemical cleaning.

Further, in the above description, the method of carrying out the rinse step using the working water is exemplified, but the rinse step may be performed by supplying the treated water in the treated water storage tank through the pipe 11. Further, this treated water may be used as the chemical dilution water for the preparation of the cleaning chemical liquid. Only one of these supply pipes for industrial water or treated water may be used.

In FIG. 1, the sludge evacuation tank and the chemical liquid storage tank are provided together, but in the present invention, the sludge evacuation tank 30 and its liquid take-out pipe 30A, liquid supply pipe 30B may be used. Alternatively, the liquid to be filtered in the membrane immersion tank during chemical cleaning may be returned to the raw water tank or the aeration tank. In this case, the liquid to be filtered may be returned to a raw water tank or an aeration tank of the same system, or may be sent to a wastewater treatment device of another system. Further, when the sludge evacuation tank 30 is provided, the liquid return pipe to the raw water tank or the aeration tank may be omitted.

Further, as described above, since the liquid in the tank can be stirred by internally circulating the liquid, the sludge evacuation tank 30
The aeration pipe 4 of the chemical solution storage tank may be omitted.

[0083]

As described in detail above, according to the present invention, by constructing the dipping tanks by dividing them into a plurality of parallel series, it is possible to provide a filtering apparatus capable of performing a filtering process in another dipping tank even during chemical cleaning. In addition to reducing the equipment cost by reducing the pumps, piping, and instruments required for chemical cleaning,
The equipment can be simplified to simplify the cleaning operation, and chemical cleaning can be performed easily and efficiently in a short time.

In particular, by detecting the end of the liquid withdrawal and the introduction of the liquid in conjunction with each step of chemical cleaning, each valve is an automatic valve, and the controller automatically opens and closes the valve and operates and stops the pump. Not only can the chemical cleaning time be shortened, but the number of operations required for chemical cleaning can be significantly reduced, or chemical cleaning can be performed without requiring any human labor, and erroneous operations can be reduced or eliminated. It is possible to prevent the chemicals from scattering due to an erroneous operation to enhance the safety, and to prevent the chemicals from being excessive or deficient and the cleaning time from being excessive or deficient, thereby obtaining a remarkably good chemical cleaning effect. It is possible to reliably carry out chemical cleaning to extend the membrane life and improve the quality of treated water. Such an excellent effect is achieved.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a membrane filtration device of the present invention.

FIG. 2 is a system diagram showing a general immersion tank.

[Explanation of symbols]

1,10,20 Membrane immersion tank 2A, 2B partition board 3A, 3B filter module (membrane module) 4 aeration pipe 5 Overflow port 30 Sludge evacuation tank 40 chemical storage tank 10A, 20A, 30A, 40A Liquid extraction pipe 10B, 20B, 30B, 40B Liquid supply pipe 10M, 20M, 30M, 40M liquid reservoir

Claims (8)

(57) [Claims] 1. A filtering device comprising a plurality of containers each having a filter body disposed therein, and one cleaning pump for supplying the liquid to each container and discharging the liquid from each container. The inside of each container communicates with the suction side of the cleaning pump through a liquid take-out pipe, and also communicates with the discharge side of the cleaning pump through a liquid supply pipe. Each liquid supply valve is provided, each liquid supply pipe is provided with a liquid supply valve, and the cleaning chemical liquid supply means of the filter body is connected to the discharge side or suction side of the cleaning pump. A filtration device characterized by: 2. A filter device comprising one or more containers each having a filter body disposed therein, and one washing pump for supplying the liquid to each container and discharging the liquid from each container. The inside of each container communicates with the suction side of the cleaning pump via a liquid take-out pipe, and also communicates with the discharge side of the cleaning pump via a liquid supply pipe. Is provided with a liquid take-out valve, each liquid supply pipe is provided with a liquid supply valve, and at least one storage tank is installed. Inside the storage tank, a liquid supply pipe having a liquid supply valve is provided. A filtering device communicating with the suction side of the cleaning pump via a filter. 3. The filtration device according to claim 2, wherein the storage tank communicates with a discharge side of the cleaning pump via a return pipe having a return valve. 4. The filtration device according to claim 1, further comprising means for communicating the discharge side of the cleaning pump with a wastewater treatment device. 5. The cleaning pump according to claim 1, wherein at least one sensor for detecting water quality is provided on a discharge side and / or a suction side of the cleaning pump. And a filtration device. 6. The filtration according to any one of claims 1 to 5, characterized in that a means for supplying a neutralizing agent for a cleaning chemical liquid is provided on a discharge side or a suction side of the cleaning pump. apparatus. 7. The filtration device according to claim 1, further comprising means for supplying fresh water or low turbidity water to the discharge side or the suction side. 8. The filtration device according to claim 1, further comprising a means for supplying a defoaming agent to a discharge side or a suction side of the cleaning pump.