JP3538385B2 - Culture solution purification apparatus and method for cleaning filtration membrane thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a culture solution purifying apparatus for purifying a nutrient solution culture solution by membrane filtration.

[0002]

2. Description of the Related Art Recently, hydroponic cultivation of tomatoes and the like has been widely performed. The nutrient solution used for such nutrient solution cultivation includes fresh water (tap water, well water) in nitrogen, phosphorus,
Fertilizer components such as potassium are dissolved, and most of the supplied culture solution is absorbed by cultivated plants, but not all is absorbed, and the unabsorbed nutrient solution is discharged as waste liquid. Was common. For the purpose of making effective use of the nutrient solution, circulation use of the nutrient solution has been attempted and put to practical use. In order to recycle such nutrient solution, it is necessary to remove impurities in the nutrient solution or to remove bacteria to prevent problems such as illness. It is being done.

[0003] However, hollow fiber membranes are very expensive, and their replacement costs are passed on to the price of cultivated crops. Here, as such a method of cleaning the hollow fiber membrane, an air scrubbing treatment in which bubbles such as air are brought into contact with the hollow fiber membrane for cleaning, or a chemical washing treatment in which the hollow fiber membrane is washed with a chemical solution such as hypochlorite. Has been done. However, the air scrubbing process cannot prevent long-term performance degradation.

[0004] On the other hand, the hypochlorite treatment requires the cost of hypochlorite to be used, and if the waste liquid is discharged as it is, it may disturb the ecological system of the environment. There is a disadvantage that the running cost of the neutralization treatment of the salt waste liquid is required.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, that is, it significantly reduces the frequency of replacing a filtration membrane of a culture solution purifying device for purifying a nutrient solution by membrane filtration. It is another object of the present invention to provide a culture solution purifying apparatus that can be stably operated for a long period of time.

[0006]

According to a first aspect of the present invention, there is provided a culture solution purifying apparatus for purifying a nutrient solution culture membrane by membrane filtration. Differential pressure detection means for detecting the differential pressure between the upstream and downstream of the membrane, flow rate detection means for detecting the filtration flow rate, air scrubbing processing means for performing air scrubbing on the filtration membrane, and hypochlorous acid for the filtration membrane The hypochlorite treatment means for performing hypochlorite treatment with a salt solution, the differential pressure between the upstream and downstream of the filtration membrane is equal to or higher than a predetermined pressure, and the filtration flow rate is equal to or higher than a predetermined flow rate. When the differential pressure between the upstream and downstream of the air scrubbing processing means and the filtration membrane that causes the air scrubbing processing means to perform the air scrubbing processing is equal to or higher than a predetermined pressure, and the filtration flow rate is lower than a predetermined flow rate, A culture purifying apparatus, comprising a hypochlorite processing determination means for causing the hypochlorite treatment chlorite processing means.

[0007] With such a culture apparatus, a method for cleaning a filtration membrane of a culture solution purifying apparatus according to the present invention according to claim 3, ie, a method for purifying a culture solution purifying a nutrient solution culture membrane by membrane filtration. In the cleaning method, the differential pressure between the upstream and downstream of the filtration membrane is equal to or higher than a predetermined pressure, and when the filtration flow rate is equal to or higher than the predetermined flow rate, an air scrubbing process is performed on the filtration membrane. A culture fluid purifying apparatus that performs hypochlorite treatment with a hypochlorite solution on a filtration membrane when a pressure difference between the downstream and a predetermined pressure is equal to or higher than a predetermined pressure and a filtration flow rate is less than a predetermined flow rate. The method for washing the filtration membrane can be easily implemented.

[0008] By such a method for cleaning the filtration membrane of the culture solution purifying apparatus, the filtration performance of the filtration membrane can be stabilized for an extremely long period with a very small amount of hypochlorite solution used.
The filtration flow rate can be maintained.

[0009] In the method for cleaning a filtration membrane of the culture solution purifying apparatus, as described in claim 4, in the hypochlorite treatment, the hypochlorous acid is washed while being in contact with the upstream side of the membrane without passing through the membrane. The ratio of the amount of the chlorate solution to the amount of the hypochlorite solution passing through the membrane for washing is set to 5: 5 to 9: 1, so that the filtration membrane can be more efficiently washed. It becomes. For this reason, the hypochlorite treatment means, in the hypochlorite treatment, the amount of the hypochlorite solution to be washed while being in contact with the upstream side of the membrane without passing through the membrane and the washing through the membrane Upstream / downstream flow ratio adjusting means for adjusting the ratio of the amount of hypochlorite solution to the amount of the hypochlorite solution, and the desired upstream / downstream flow ratio can be adjusted by the upstream / downstream flow ratio adjusting means.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to all circulating culture solutions in which a membrane is separated by a filtration membrane in a nutrient solution culture of vegetables such as tomato, pepper, melon, zucchini, cucumber, lettuce, saladana, watercress and spinach. It can be applied to purification equipment. Examples of such a filtration membrane include hollow fiber, tubular, and spiral filtration membranes.

The present invention is particularly effective for hollow fiber type filtration membranes having pores of 0.45 μm or less and capable of removing bacteria. In the present invention, the scrubbing treatment means that air bubbles are brought into contact with the upstream side of the filtration membrane to remove dirt, bacteria and the like attached to the surface thereof ("upstream" and "downstream side" of the filtration membrane in the present invention). ”Means“ upstream ”the direction in which the required culture medium is supplied to the filtration membrane, with the filtration medium as a reference, based on the flow of the culture medium to be filtered, and the filtration culture medium filtered by the filtration membrane is cultured again. The direction supplied to the plant is called "downstream").

The scrubbing treatment is desirably performed vigorously so as not to damage the filtration membrane. That is, the air pressure is 0.1 MPa, and the air amount is 1.5 per m ² of the membrane area.
The processing time is usually about 5 to 10 minutes.

Such a scrubbing process needs to be performed when the pressure difference between the upstream and downstream of the filtration membrane becomes equal to or higher than a predetermined pressure. The predetermined pressure is, in the case of a culture solution,
This is a value obtained by adding 0.01 MPa or more and 0.03 MPa or less to the initial differential pressure. When the pressure falls within this range, a scrubbing process is performed.

Here, the pressure at the time of supplying the culture solution to the filtration membrane of the culture solution purifying apparatus of the present invention is usually 0.15 MPa or more and 0.25 MPa or less. By the above-described appropriate scrubbing treatment, ordinary dust and bacteria are detached from the surface of the filtration membrane and dispersed in the liquid phase, so that the liquid in which the dust and bacteria are dispersed is discharged.

Although the pressure difference before and after the filtration membrane is reduced by such a scrubbing treatment, it is formed by some of the general bacteria (10 ⁷ to 10 ⁸ cells / mL) present in the culture solution. There is not much effect when slime or the like sticks to the filtration membrane and closes the pores thereof, and the pressure difference between before and after the filtration membrane increases, and at the same time, the flow rate of the culture solution passing through the filtration membrane decreases. Therefore, when the differential pressure before and after the filtration membrane is equal to or higher than a predetermined pressure, and the filtration flow rate of the culture solution is less than the predetermined flow rate, the hypochlorite treatment of the filtration membrane with a hypochlorite solution is performed on the filtration membrane. I do.

[0016] The hypochlorite treatment is to wash the filtration membrane with an aqueous solution of hypochlorite such as sodium hypochlorite and potassium hypochlorite. Can be eliminated. At the same time, the slime-forming bacteria can be sterilized by sterilizing the vicinity of the filtration membrane by the effect of these agents, and the pore can be prevented from being blocked again.

The effective chlorine concentration in such a hypochlorite solution is usually 70 mg / L or more and 200 mg / L or less, and less than 70 mg / L is less effective.
If the concentration exceeds 0 mg / L, the effect due to the increase in concentration is almost flat, the handling property is deteriorated, and the filter membrane and the surrounding materials may be deteriorated. Become.

In the hypochlorite treatment, it is preferable that the hypochlorite solution is in contact with the upstream side of the filtration membrane and cleans the surface thereof, and a part of the hypochlorite solution flows downstream through the filtration membrane. . At this time, the ratio of the amount of the hypochlorite solution to be washed while contacting the upstream side of the membrane without passing through the membrane and the amount of the hypochlorite solution (washing solution) to be washed through the membrane is When the ratio is 5: 5 to 9: 1, particularly effective cleaning becomes possible. This is presumed to be due to the fact that the cleaning liquid optimally acts on the front and back of the filtration membrane.

Such hypochlorite treatment is usually carried out in the range of 1 to 2
Do time. Then, after removing the hypochlorite solution, the filtration membrane and its surroundings are thoroughly washed with clear water, and after draining,
The culture solution is introduced into the filtration membrane, and filtration is started. With such a configuration, stable operation for a long time, which cannot be achieved by the conventional method for cleaning a filtration membrane of a culture solution purifying apparatus, can be achieved.

FIG. 1 shows a block diagram of a culture solution purifying apparatus of the present invention. In FIG. 1, reference numeral α denotes a cultivation tank, and the culture solution is purified and circulated through a filtration membrane A of a culture solution purification device δ of the present invention by a line β and a pump γ. At this time, the differential pressure between the upstream and downstream of the filtration membrane A is detected by a differential pressure detecting means B such as a differential pressure gauge, and the differential pressure is equal to or higher than a predetermined pressure and detected by a flow rate detecting means C such as a flow meter. When the detected filtration flow rate is equal to or more than the predetermined flow rate, the air scrubbing processing determining means D causes the air scrubbing processing means E to perform the air scrubbing processing on the filtration membrane A.

If the differential pressure detected by the differential pressure detecting means B is equal to or higher than a predetermined pressure and the filtration flow rate detected by the flow rate detecting means C is less than the predetermined flow rate, hypochlorite is used. The processing determining means F causes the hypochlorite processing means G to perform hypochlorite processing on the filtration membrane A.

In this hypochlorite treatment means G, the amount of the hypochlorite solution to be washed while being in contact with the membrane upstream without passing through the membrane and passing through the membrane in the above-mentioned hypochlorite treatment Upstream / downstream flow ratio adjusting means H for adjusting the ratio to the amount of the hypochlorite solution to be washed with water is attached. In addition,
Although not shown in this example, the culture solution purifying device may control the on / off of the pump γ as necessary.

The control of the culture solution purifying apparatus can be controlled by using, for example, a microcomputer.
FIG. 2A shows a piping diagram of an example of the culture solution purifying apparatus of the present invention. The line from the cultivation tank on the upstream side of the filtration membrane F has a solenoid valve V ₁ (to prevent a waste liquid such as a scrubbing treatment and a hypochlorite treatment from flowing back toward the cultivation tank) and a pump Po. chemical lines and fresh water lines are connected to a branch between the solenoid valve V ₁ and the pump Po.

The electromagnetic valve V ₆ is the chemical lines, chemical tank K is provided upstream of the solenoid valve V _6. Also, Shimizu line for supplying washing water to clean the filtration membrane surrounding after hypochlorite process is connected to the water supply via a solenoid valve V ₉

The inlet side of the filtration membrane F, the differential pressure gauge M ₁ is the outlet side is provided so as to detect a differential pressure between upstream and downstream of the filtration membrane F. An electromagnetic valve V ₇ , a flow meter M ₃ for adjusting the amount of liquid that does not pass through the filtration membrane during hypochlorite treatment, and a flow control valve V ₇ ′ are provided below the upstream side of the filtration membrane F. upstream hypochlorite reflux line adapted chemical solution is returned to tank K, filtration membranes surrounding drainage drain line having an electromagnetic valve V _5, and compression for air scrubbing process through the solenoid valve V ₃ The air supply line is connected.

[0026] filtration membrane F upstream upward, vent line for the exhaust-air having a solenoid valve V ₄ is provided. Further, below the filtration membrane F, a solenoid valve V ₈ and a flow meter M ₄ for adjusting the amount of liquid passing through the filtration membrane during hypochlorite treatment are provided.
And a downstream-side hypochlorous acid reflux line having a flow control valve V ₈ ′ and a chemical solution returning to the chemical solution tank K.

The solenoid valve V ₂ is provided at the outlet of the filtration membrane F is waste such as scrubbing process during and hypochlorite process is prevented from flowing in the culture tank direction. These solenoid valves V ₁ ~V ₉ are respectively connected to the output port O ₁ ~ O ₇ microcomputer MP, open the signal "ON" is output to each of these output ports, signal "OFF" is output And closes.

The pump Po is a microcomputer M
Are connected to P output ports O10, running the signal "ON" is output to the output port O _10, so that the stops when the signal "OFF" is output. These solenoid valves and pumps are "OFF" as initial values, and the solenoid valves are closed and the pumps are stopped before the operation of the apparatus is started.

The output of the differential pressure gauge M _{1 and} the output of the flow meter M ₂ are connected to the input port I of the microcomputer MP, respectively.
It is adapted to be taken into the microcomputer MP through ₁ and I _2.

The microcomputer MP also includes a central control circuit CPU, timer variables T ₁ , T ₂ and T _3.
Readable and writable memory RAM (FIG. 2
(B) and data a ₁ of a predetermined differential pressure set in advance,
Predetermined flow rate data a ₂ , air scrubbing time t ₁ , hypochlorite time t ₂ , and
A read-only memory (FIG. 2) in which data t _{3 of} the time required for drainage around the filtration membrane, data t _{4 of the} washing time, etc., or a program of the central control circuit CPU is written.
(C)).

The operation of such a culture solution purifying device will be described with reference to the flowchart of FIG. After the start, the output of the signal "ON" to the output port O _1, O ₂ and O ₁₀ in step S _1, the electromagnetic valve V ₁ and V ₂ are opened, the pump Po is running, circulating cleaning of culture Is started.

[0032] reaches a pressure a ₁ value of the input port I ₁ is a differential pressure data is given from the differential pressure gauge M is a differential pressure detecting means for detecting a differential pressure between upstream and downstream of the step S ₂ in the filtration membrane Check for a, when it is less than a predetermined pressure a ₁ repeats the steps S _2, the process proceeds to step S ₃ when the predetermined pressure a ₁ or more.

[0033] investigated whether the value of the input port I ₂ is a filtration flow rate data from the flow meter M ₂ which is a flow rate detecting means for detecting the filtered flow in step S ₃ has not reached the predetermined flow rate a _2, a predetermined flow rate the process proceeds to step S ₁₀ when it is a ₂ or more, the process proceeds to step S ₂₀ when it is less than the predetermined flow rate a _2.

The signal "OFF" is output in step S ₁₀ output ports O _1, O ₂ and O _10, valves V ₁ and V ₂ are closed, the culture solution purification device is disconnected from the culture fluid line, At the same time, the pump Po stops.

[0035] Then the signal "ON" to the output port O ₃ and O ₄ in step S ₁₁ is outputted, the valve V ₃ and V ₄ are opened, and compressed air is supplied to the upstream side of the filtration membrane F, air scrubbing Processing is started.

The timer T ₁ in step S ₁₂ is started after being reset, the process to reach t ₁ is air scrubbing process a predetermined time in step S ₁₄ is continued.

After the timer T ₁ has reached the predetermined air scrubbing processing time t ₁ , a signal “OFF” is output to the output port O ₃ in step S ₁₄ , the valve V ₃ is closed, and the air scrubbing processing is performed. Ends. Then, the signal "ON" is output to the output port O ₅ in step S _15, the valve V ₅ is opened, dust detached from the filtration membrane by air scrubbing, broth filtration membrane surrounding the like are dispersed dirt discharge Is done.

[0038] Starting after the timer T ₂ is reset in step S _16, after the state of the valve to reach t ₂ is maintained a drainage predetermined time in step S _17, output in step S ₁₈ signal to port O ₄ and O ₅ "OF
F "is outputted, the valve V ₄ and V ₅ are closed, then the process returns to step S _1, again, the circulation filtration is started cultures.

On the other hand, step S_ThreeTo step S₂₀Proceed to
Output port O₁And O _TwoSignal "OFF"
Is output, the valves V1 and V2 are closed, and this culture is performed.
The liquid purifier is disconnected from the culture solution line.

The output port O ₆ in step S _21, O ₇ and O
₈ , a signal “ON” is output, valves V ₆ , V ₇ and V ₈ are opened, and the hypochlorite solution prepared in advance in the chemical solution tank K is circulated and supplied to the filtration membrane, and hypochlorous acid is added. Salt treatment is performed. At this time, the hypochlorite for cleaning through the amount and film hypochlorite solution for cleaning in contact therewith without film upstream (i.e. valve V ₇ passing liquid amount) passing through the filtration membrane The valves V ₇ ′ and V ₈ ′ are adjusted so that the ratio to the amount of the solution (that is, the amount of liquid passing through the valve V ₈ ) is 5: 5 to 9: 1.

[0041] Starting after the timer T ₃ is reset in step S _22, hypochlorous salt treatment is continued until the t ₃ is a hypochlorite treatment predetermined time in step S _23.

The signal "OFF" is outputted to the output port O ₆ and O ₁₀ in step S _24, the valve V ₆ is closed,
At the same time, the pump Po stops. The signal "ON" to the output port O ₄ in the next step S ₂₅ is outputted, the valve V ₄ is opened, hypochlorite nutrient solution downstream hypochlorite reflux line and the upstream side near the filtration membrane following Collected from the chlorite reflux line into the chemical tank.

Step S₂₆With timer T_TwoIs reset
Start after step S₂₇Then, the predetermined
T is the liquid time_TwoThe state of the valve is maintained until it reaches.
Step S₂₈Then output port O_Four, O₇And O₈Signal
“OFF” is output and the valve V_Four, V₇And V₈Is closed
And then step S₂₉Output port O_Five, O ₉as well as
O_Ten"ON" is output to the valve V_FiveAnd V₉Is open
Then, the pump Po operates and the filter membrane is washed with water.
You.

The process starts after the timer T ₄ is reset in step S _{30. In} step S ₃₁ , the state of the valve and the pump is maintained until the timer T ₄ reaches a predetermined washing time t ₄ .

After reaching a predetermined washing time t ₄ , a signal “OFF” is output to the output ports O ₉ and O ₁₀ in step S ₃₂ , the valve V ₉ is closed and the pump Po is stopped. Then, the water washing process ends. Then
The output port O ₄ in step S ₃₃ the signal "ON" is output, the valve V ₄ is opened, washing water around the filtration membrane is discharged.

After the timer T ₂ is reset in step S ₃₄ , the process is started. In step S ₃₅ , the state of the valve is maintained until the timer T ₂ reaches a predetermined drainage time t _2. S35 signal "OFF" is outputted to the output ports O ₄ and O _5, the valve V4 and V5
Is closed, and then the process returns to step S1, and circulation filtration of the culture solution is started again.

As is apparent from various parts of the action of such devices, the differential pressure gauge M ₁ is the differential pressure detecting means for detecting a differential pressure between upstream and downstream of the filtration membrane, the flow meter M ₂ detects the filtration flow Air scrubbing, which is a flow rate detection means, and causes the air scrubbing processing means to perform an air scrubbing process when a differential pressure between the upstream and downstream of the filtration membrane is equal to or higher than a predetermined pressure and the filtration flow rate is equal to or higher than a predetermined flow rate. The hypochlorite treatment is performed by the hypochlorite treatment means when the pressure difference between the upstream and downstream of the processing determination means and the filtration membrane is equal to or higher than a predetermined pressure, and the filtration flow rate is less than the predetermined flow rate. Hypochlorite treatment determining means to be performed is microcomputer M
P, and the compressed air supply line, piping, and valves perform air scrubbing on the filtration membrane.
o The hypochlorite treatment means in which the piping and each valve perform hypochlorite treatment with a hypochlorite solution on the filtration membrane, as well as the flow meters M3 and M4 and the flow control valve V ₇ ′ The amount of hypochlorite solution to be cleaned while V ₈ ′ is in contact with the upstream side of the membrane without passing through the membrane in the hypochlorite treatment, and the hypochlorite solution to be cleaned by passing through the membrane Corresponding to upstream / downstream flow ratio adjusting means for adjusting the ratio with the amount of water

[0048]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The purification of a culture solution by the culture solution purification apparatus of the present invention will be specifically described below. The following experiment was performed using the culture solution purifying apparatus whose piping and circuit diagram is shown in FIG. The culture solution is a culture solution for tomato hydroponics, and the filtration membrane is CP-2020 manufactured by Toray (membrane filtration accuracy: molecular weight cut off 10,000).
Using 0), circulation filtration was performed.

In the embodiment according to the present invention (the combined use of the air scrubbing treatment and the hypochlorite treatment), the initial pressure difference between the upstream and downstream of the filtration membrane was 0.18 MPa, and the pressure difference was 0.20 MPa. (“A ₁ ” in the above example)
And, the flow rate is 1,400 L / h with respect to the initial value of 1,600 L / h.
L / h (“a ₂ ” in the above example) or more, the air scrubbing treatment was performed, and the initial pressure difference between the upstream and downstream of the filtration membrane was 0.18 MPa, and the differential pressure was 0.20 MPa (the above example). "A ₁ ") or more and the flow rate is 1400
When it was less than L / h, hypochlorite treatment was performed.

On the other hand, for the sake of comparison, the circulating filtration of the culture solution was carried out in the same manner as in the example, and the membrane cleaning according to the prior art was carried out in comparative example 1
In the example in which only the air scrubbing treatment was performed alone, the differential pressure between the upstream and downstream of the filtration membrane (initial differential pressure: 0.18
When the pressure (MPa) reached 0.20 MPa, an air scrubbing treatment was performed. In Comparative Example 2, the circulating filtration of the culture solution was performed in the same manner as in the example, and in the example in which only the hypochlorite treatment was performed alone for membrane washing, the filtration flow rate was 14%.
The hypochlorite treatment was performed when the water content became 00 L / h or less.

The air scrubbing process is performed for 10 minutes,
An air scrubbing treatment was performed on the upstream side of the filtration membrane under the conditions of an air supply pressure of 0.1 MPa and an air supply amount of 20 NL / min. On the other hand, the hypochlorite treatment was performed by supplying a 100 mg / L aqueous solution of sodium hypochlorite (normal temperature) to the membrane at a rate of 500 L / h for one hour. In this hypochlorite treatment, the amount of the hypochlorite solution to be washed while being in contact with the membrane upstream without passing through the membrane and the hypochlorite solution to be washed through the membrane The ratio with the amount (upstream / downstream flow ratio) was set at 6: 4.

FIG. 4 also shows the change over time of the filtration flow rate at this time (the air scrubbing treatment time and the hypochlorite treatment time are omitted). In each of FIG. 3, each serrated peak indicates that the flow rate was restored after each cleaning treatment. In addition, the places marked with “●” indicate that the hypochlorite treatment was performed.

From FIG. 4, it can be seen that the frequency of hypochlorite treatment in the example of the present invention is about 1/4 as compared with Comparative Example 2 in which hypochlorite treatment alone is used. In Comparative Example 1 in which only the scrubbing treatment was performed, it can be seen that the amount of the permeated liquid is extremely stable as compared with the case where the amount of the permeated liquid gradually decreases.

FIG. 5 shows the amount of permeated water when the process of the above embodiment was continued for a long period of time. FIG. 5 shows that stable processing can be performed over a long period of time. In the case of Comparative Example 2 in which the treatment with hypochlorite alone was performed, the amount of permeated water gradually decreased, and the filtration membrane had to be replaced in about 15 days.

Next, in the hypochlorite treatment, the amount of the hypochlorite solution to be washed while being in contact with the upstream side of the membrane without passing through the membrane and the hypochlorite to be washed through the membrane The ratio to the amount of the solution (upstream / downstream flow ratio) was examined. Note that the upstream / downstream flow ratio is the flow meter M ₃ in FIG.
By adjusting the flow control valves V ₇ ′ and V ₈ ′ while watching the instructions of M ₄ and M ₄ .

As in the first embodiment, the flow rate adjusting valves V ₇ ′ and V ₈ ′ are adjusted while observing the instructions of the flow meters M ₃ and M ₄ in FIG. 2 to change the upstream / downstream flow rate ratio. The apparatus was operated, and the amount of permeated water when the use / washing treatment was repeated five times with hypochlorite treatment was examined. Table 1 shows the recovery rate when the value of the initial permeated water amount is 100%.

[0057]

[Table 1]

As shown in Table 1, in the hypochlorite treatment, the amount of the hypochlorite solution to be washed while being in contact with the upstream side of the membrane without passing through the membrane and the hypochlorite to be washed by passing through the membrane Ratio to the amount of acid salt solution (upstream / downstream flow ratio) is 5: 5
It turns out that when it is 9: 1, an extremely high recovery rate is shown.

[0059]

The culture solution purifying device of the present invention is an excellent culture solution purifying device.

[Brief description of the drawings]

FIG. 1 is a block diagram of a culture solution purifying apparatus of the present invention.

FIG. 2 is a piping and wiring diagram of an example of the culture solution purifying apparatus of the present invention.

FIG. 3 is a flowchart for explaining the operation of the apparatus of FIG. 2;

FIG. 4 is a graph showing the effect of the method for cleaning a culture solution purifying device of the present invention.

FIG. 5 is a graph showing that stable filtration can be performed over a long period of time by the method for cleaning a culture solution purifying device of the present invention.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshiaki Shibuya 4-4 Midorigahara, Tsukuba, Ibaraki Prefecture Aquas Co., Ltd. Tsukuba Research Institute (72) Inventor Toshinobu Tokumaru 4-4 Midorigahara, Tsukuba City, Ibaraki Prefecture In-house (56) References JP-A-7-275671 (JP, A) JP-A-9-107826 (JP, A) JP-A-9-253645 (JP, A) JP-A-9-29070 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B01D 61/00-61/58 A01G 31/00

Claims (4)

(57) [Claims] 1. A culture solution purifying device for purifying a nutrient solution culture solution by membrane filtration, comprising: a differential pressure detecting means for detecting a differential pressure between upstream and downstream of a filtration membrane; a flow rate detecting means for detecting a filtration flow rate; Air scrubbing means for performing air scrubbing treatment on the membrane; hypochlorite treatment means for performing hypochlorite treatment with a hypochlorite solution on the filtration membrane; and upstream and downstream of the filtration membrane. When the differential pressure exceeds a predetermined pressure,
And, when the filtration flow rate is equal to or more than a predetermined flow rate, the differential pressure between the upstream and downstream of the air scrubbing determination means and the filtration membrane that causes the air scrubbing processing means to perform the air scrubbing processing is equal to or higher than a predetermined pressure, and A culture solution purifying apparatus, comprising: hypochlorite treatment determining means for causing the hypochlorite processing means to perform hypochlorite treatment when the filtration flow rate is less than a predetermined flow rate. 2. The method according to claim 1, wherein the hypochlorite treatment means is configured to perform the cleaning while passing through the membrane and the amount of the hypochlorite solution for cleaning while contacting the upstream side of the membrane without passing through the membrane. The culture solution purifying apparatus according to claim 1, further comprising an upstream / downstream flow rate ratio adjusting means for adjusting a ratio with respect to the amount of the salt solution. 3. A method for cleaning a filtration membrane of a culture solution purifying device for purifying a nutrient culture solution by membrane filtration, wherein a differential pressure between upstream and downstream of the filtration membrane is equal to or higher than a predetermined pressure,
And, when the filtration flow rate is equal to or higher than a predetermined flow rate, an air scrubbing process is performed on the filtration membrane, and the differential pressure between the upstream and downstream of the filtration membrane is equal to or higher than a predetermined pressure, and the filtration flow rate is lower than the predetermined flow rate. A method for cleaning a filtration membrane of a culture solution purifying apparatus, wherein the filtration membrane is subjected to hypochlorite treatment with a hypochlorite solution. 4. In the hypochlorite treatment, the amount of the hypochlorite solution to be washed while being in contact with the upstream side of the membrane without passing through the membrane and the hypochlorous acid to be washed through the membrane The method according to claim 3, wherein a ratio of the amount of the salt solution to the amount of the salt solution is 5: 5 to 9: 1.