JPH10137783A - Virus removing method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mass-treat water to be treated and to improve a removing efficiency without exerting adverse influence on an effuluent place by passing the water through the area of membrane pores where Hymenostomatida Ciliatea exists, thereby simplifying a system. SOLUTION: A porous carrier 2 is packed in a column 1, and as inlet 3 of the water to be treated and an air inlet 5 are arranged in the upstream side of the column 1. A discharge port 4 of a treated water and an air outlet 6 are arranged in a downstream side of the column 1. Then valves 3a to 6a are fitted respectively. The Ciliatea is allowed to settle down at the hole part or on the surface of the porous carrier 2. Amounts of influent-effluent of the air are controlled with air valves 5a and 6a in accordance with a nature of the Ciliatea. Then bacteria and virus existing underwater are eaten and removed with the Ciliatea when the water to be treated is made to flow in the column 1. In this way, the many viruses are removed by treating continuously without using a batch type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a virus removing method and a virus removing device capable of removing viruses present in wastewater. The method and apparatus of the present invention can be applied to various types of water in the environment, such as sewage, sewage secondary treated water,
Contaminated lake water, river water, marine water, park ponds, aquariums,
It can be used to remove viruses contained in water systems such as pool water.

[0002]

2. Description of the Related Art There are many viruses in nature, but viruses have the property of infecting only a specific host, and are often detected only in the infected state. Therefore, it is difficult to accurately grasp the type and number of viruses in a natural environment, and it is more difficult to examine inactivation (death) of each virus.

However, with the recent development of virus detection technology, many types of viruses have begun to be identified, and it is becoming clear that many viruses exist in the water system of our living environment. These viruses can sometimes harm humans, livestock, and crops. For example, it is known that virus present in water systems causes food-toxic diarrhea. Particularly in cities, the rapid increase in population has led to an increase in the amount of sewage and the recycling of water resources, and the problem of viruses present in these water systems has been pointed out.

As a method for removing or inactivating a virus that inhabits an aqueous system, a method of chemically killing with a chemical such as chlorine or chlorine dioxide (conventional example) and a method of physicochemical killing with ozone (conventional example) There are known a method of killing by ultraviolet irradiation (conventional example), a method of killing by heat treatment (conventional example), and a method of removing virus by filtration using a membrane (conventional example).

[0005] However, in the above conventional example, there is a problem that chemical substances such as chlorine remaining after the treatment adversely affect the environment. For example, an organochlorine compound generated from residual chlorine has an adverse effect on aquatic organisms to which it is released, and has become a social problem. Further, the above conventional example does not have the adverse effects of the residual chemical substances as described above, but has a problem that the cost required for the treatment is high, and is not suitable for treating a large amount of water. In addition, in the conventional example, the effect fluctuates significantly depending on the amount of suspended turbid components present in the water to be treated and the amount of water to be treated, and the effect is reduced by dirt on the ultraviolet lamp. There is a need. In addition, in the above-mentioned conventional examples, since these methods are usually performed under general bacterial disinfection conditions, it is known that the virus tends to remain resistant and resistant. Further, the above-mentioned conventional example is not suitable for a large amount of processing, and is ineffective for heat-resistant viruses. In addition, in the above-mentioned conventional examples, the killed cells themselves remain in the treated water, so that the water cannot be purified without further additional treatment.

[0006] On the other hand, the above-mentioned conventional example is a good method in that the virus itself can be removed and sewage is purified. However, since the filter membrane is easily clogged,
It is necessary to frequently perform back washing of the filtration membrane or exchange of the filtration membrane, which increases the processing cost. In addition, when the amount of impurities is large, there is a problem that the removal efficiency is reduced and a large-scale apparatus is required.

[0007] Due to the above problems, the above-described conventional example is used in a facility such as a medical institution where virus removal is particularly essential, or the conventional example is used for the purpose of inactivating some viruses. Only.

In order to solve the above problems, Japanese Patent Laid-Open No.
No. 51973 (conventional example) and JP-A-4-158865 (conventional example)
Alternatively, a new virus removal method has been proposed in JP-A-56-67581 (conventional example).

In the above-mentioned conventional example, an object to be processed is passed between electrodes, and a virus is inactivated by the action of a voltage or a current applied between the electrodes.
The oxidizing agent or other active substance is added to oxidize and kill the virus. In the above-mentioned conventional example, the virus is killed by adsorbing the virus on an ionic adsorption carrier and subjecting the virus to a photooxidation treatment. It is to remove.

[0010]

However, the above-mentioned conventional example requires a large-scale apparatus, and therefore has a problem that the cost is high. In the above-mentioned conventional example, there is a concern that the above-mentioned additive substance may adversely affect the discharge destination. Further, in the above-mentioned conventional example, there is a problem that the maintenance cost of the ionic adsorption carrier is high, and many unsolved problems remain.

By the way, oysters are known to have the ability to filter water, and the water circulation rate of one individual reaches as much as 30 liters / day. In the process of water circulation, oysters take up viruses into their bodies, and for example, Norwalk virus contamination of oysters by this uptake is well known. Therefore, if such a virus accumulation effect of oysters is utilized, there is no problem such as release of added substances and the like, so it was expected that the virus could be removed without adversely affecting the water environment of the release destination. However, since oysters are shellfish, their growth is difficult to control and their growth is slow, and they are not practical for large amounts of water.

In view of the above, the present invention has been made in view of the above problems, and can be processed in a large amount by a simple system, does not adversely affect a discharge destination, and furthermore, has a processing facility and an operation for the operation thereof. It is an object of the present invention to provide a virus removal method and a virus removal device with low maintenance cost and high removal efficiency.

[0013]

The gist of the virus removing method according to the present invention is to allow the water to be treated to pass through a region where the ciliates of the order Membrane are present. Further, the virus removal device according to the present invention includes a region where the ciliates of the order of the membrane exist, and has an inlet for inflowing the water to be treated into the region and an outlet for discharging the treated water from the region. Is the gist.

The present inventors have found through experiments that ciliates of the order Membrane have the property of taking up viruses. Moreover, the ciliates of the membrane mouth are easy to control and handle the growth,
In addition, since this virus uptake can be performed by an extremely simple method of merely flowing the water to be treated into the area where the ciliates inhabit, the treatment system can be simplified, and equipment and running costs can be reduced. It can be inexpensive. In addition, since the removal method uses the ciliates to take in the virus, there is no adverse effect on the water environment at the release destination. Ciliates that have taken in viruses can be easily rendered harmless by incineration.

The mode of virus uptake by ciliates is discussed below. Ciliates gain nutrients by predating bacteria and other small organisms, and their predation is achieved by filtering water using many minute cilia and capturing bacteria contained in the water. , To take into the body. In addition, even when there are no bacteria around, they move by ciliary movement, and at this time, they have a habit of filtering out water and taking in organic substances contained in the water as nutrients.

Viruses are of little value in nutrition, but when ciliates prey on nutrients such as bacteria as described above, surrounding viruses are also taken in at the same time. It will be removed.

Among the ciliates, the ciliates of the order Membranes are particularly active without forming cysts.
Because of good growth and vigorous predation and filtration, the virus can be removed continuously and well. still,
The ciliates of the membrane mouth have a length of 100 μm or less and a width of 50 μm.
It belongs to small ciliates of less than μm. Further, the device according to the present invention provides a device having a diameter of
Those having a porous carrier having a hole diameter of ５００500 μm are preferred.

It is better to have a large number of ciliates in order to remove a large amount of virus, but it is not possible to inhabit a large number of ciliates if there is no habitable place. However, if the porous carrier is provided, an environment in which ciliates can easily live is provided, and the ciliates can live at a high density. In addition, since the ciliate is carried on the porous carrier, the outflow of the ciliate can be prevented, so that the growth state of the ciliate can be stabilized and a good high density can be maintained. Therefore, the virus removal efficiency is improved.

The pore diameter of the porous carrier is 50 μm.
m or more is preferable, and this size is desirable as a ciliate habitat because ciliates can move freely in the hole and bacteria (ciliate feed) can easily enter the hole. On the other hand, if the hole diameter is too large, the ciliate will flow out without being fixed, and it will be impossible to grow the ciliate at a high density. Therefore, the diameter is preferably 500 μm or less. In addition, as a result of microscopic observation, when the hole diameter was 5 times or less the size of the ciliate, it was recognized that the retention of the ciliate in the hole was particularly good. It is good to select the hole diameter according to.

Examples of the porous carrier include a silica-based carrier, a cellulose-based carrier, a chitin-based carrier, a polyurethane-based carrier, a carbon-based carrier, a ceramic-based carrier, and a carrier of a gel polymer such as polyvinyl alcohol, carrageenan, and alginic acid. Among them, cellulose-based carriers and polyurethane-based carriers are most preferred. The shape of the porous carrier is not particularly limited.
Lattice shape, pellet shape, thread shape, fiber shape, sponge shape are mentioned.

In the virus removing apparatus according to the present invention, it is preferable that the area where the ciliates exist is surrounded by a membrane having a pore size larger than viruses and bacteria and smaller than the ciliates.

In other words, the membrane is a membrane that can transmit viruses and bacteria and cannot pass through the ciliates. By surrounding the ciliate growth area with the membrane, the ciliates can be prevented from flowing out and ciliates can be prevented. Inhabit in high density and enhance the virus removal effect. On the other hand, the bacteria (feed) and the virus to be removed need to enter the membrane in which the ciliates live, so that the membrane is permeable to viruses and bacteria as described above. Since this membrane has a larger pore diameter than the conventional example, it does not cause much clogging and does not need to be replaced frequently. Specifically, the pore diameter of the membrane is preferably 2 to 6 μm. The pore size of the membrane may be appropriately selected according to the size of the ciliate insect used.

Examples of the material of the membrane include cellulose, polysulfone, polyethylene, and polycarbonate. Among them, polycarbonate is most preferred. The type of the membrane may be appropriately selected according to the ciliate to be used. In addition, the porous carrier may be surrounded by the membrane. Further, in the present invention, it is more preferable that the region surrounded by the membrane is configured to be exchangeable, so that ciliates and carriers can be totally exchanged.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Experiments on the effectiveness of ciliates of the order Membrane used in the present invention are described below. <Experiment 1: Study on virus removal by protozoa>
Ciliates (Examples) and Flagellates (Comparative Examples) as Protozoa
Was examined. Using a 60-ml culture flask, 500 ciliates / ml in 10 ml of artificial secondary treatment water
Was inoculated. As the ciliate, the length is 30 to
One type of a membrane having a width of 60 μm and a width of 5 to 10 μm was used. The composition of the artificial secondary treatment water is as shown in Table 1 below, and sterilized by an autoclave at 121 ° C. for 5 minutes before use.

[0025]

[Table 1]

P. florescenc is used as a bait in the above ciliate solution.
e ) about 1 × 10 ⁸ CFU / ml, and
A sample to which 2 × 10 ⁴ PFU / ml of NA phage was added (sample 1) and a sample to which 2 × 10 ⁶ PFU / ml were added (sample 2)
Was prepared. The RNA phage Qβ of Escherichia coli is a virus that can be assayed safely in a general laboratory, and has properties similar to those of human-derived pathogenic viruses such as influenza virus and poliovirus. It was decided to use it as a substitute.

Using a 60 ml culture flask, 10 ml of the artificial secondary treated water was inoculated with microflagellates having a length of 10 μm or less and a width of 5 μm or less so that the number of solids was about 10 ⁴ / ml. Similarly, about 1 × 10 ⁸ CFU / ml of P.florescence cells and 2 × 10 ⁴ PFU / ml of E. coli RNA phage Qβ (sample 3), and 2 × 10 ⁶ PFU / ml An additive (Sample 4) was prepared.

As a control, the same conditions were used except for ciliate and flagellate (Control 1: E. coli RN).
A phage Qβ2 × 10 ⁴ PFU / ml, control 2: E. coli RNA phage Qβ2 × 10 ⁶ PFU / ml) were prepared.

The above Samples 1 to 4 and Controls 1 and 2 are cultured with shaking in a thermostat at 25 ° C. After a predetermined culture period, a part of each of Samples 1 to 4 and Controls 1 and 2 is separated as a test sample. The numbers (concentrations) of viruses, bacteria, ciliates and flagellates were measured by the following methods. The above culture was performed by a batch method, and ciliates, bacteria, viruses, and flagellates were added only at the start of culture, and were not added later.

The composition of the medium for measuring the number of viruses is shown in Table 2 below. These components were dissolved in distilled water to obtain 1N-N
Adjust the pH to 7.0 ± 0.2 with aOH, and add 15
After sterilization for 1 minute, the medium was used as a medium for measuring the number of viruses.

[0031]

[Table 2]

The method for measuring the number of viruses was E. coli K-12.
Using the (F +) strain as the indicator bacterium, the double agar method was used (Reference: T. Loeb and NDZinder, PNAS47 No.
282, 1961), the test sample was sown on the medium together with the indicator bacteria, and cultured at 37 ° C. for 24 hours, and the number of plaques formed was counted to determine the number of viruses. In the measurement of the number of viruses in the test sample, the test was performed as it was or after appropriate dilution. The measurement of the number of bacteria (live bacteria)
The test sample was inoculated on a standard agar medium, cultured at 30 ° C. for 48 hours, and the number of colonies was counted. The number of ciliates and flagellates was measured by visual observation with a microscope.

FIG. 1 is a graph showing the results of measurement of the numbers of viruses, bacteria, and ciliates after each culture period. still,
FIG. 1 (a) shows the case of sample 1, and FIG. 1 (b) shows the case of sample 2.
Is the case.

As can be seen from the results, one day of culture (24
After time h), the ciliate population increased and the bacterial count decreased. Further, when the liquids of Samples 1 and 2 were visually observed, turbidity due to P. florescence cells was observed at the start of the culture, but this turbidity was reduced one day after the cultivation, and the observation results and From the results shown in FIG. 1, it can be seen that the number of bacteria was reduced by predation of ciliates.

On the other hand, the number of viruses hardly changed after 1 day of culture, but a decrease in the number of viruses was observed after 2 days (48 hours) of culture. This decrease was about 85% in sample 1 and about 79% in sample 2 as compared with the time when the virus was added. Furthermore, the number of viruses further decreased as the culturing period was prolonged, and after 7 days of culturing, the number of viruses was reduced by 99.1% as compared with the initial addition, indicating that the virus was removed well.

FIG. 2 is a graph showing the relationship between the number of viruses and the culture period for samples 1 and 2. Samples 1 and 2 have the same number of added bacteria and different numbers of added viruses.
As can be seen from FIG. 2, regardless of the number of viruses at the beginning, the virus decreases at the same reduction rate (slope). In other words, the virus reduction of sample 1 is about [10 ⁴ −10 ² = 9900] PFU / ml. On the other hand, the sample 2 was approximately [10 ⁶ -10 ⁴ = 99
0000] PFU / ml virus reduction. Since the amounts of ciliates are the same for both samples 1 and 2, if ciliates prey on virus tropism, there should be no significant difference in virus predation. However, as described above, sample 1
From the results, it is inferred that the removal of the virus is not predation due to the virus tropism of ciliates but predation that accompanies predation of bacteria and the like. In addition, since the ciliates are not virus-tropic as described above, even if various types of viruses are present, they are taken up without being distinguished by the type of virus, and therefore, the content of all viruses in the water to be treated is included. It can be seen that the virus removal rate can be estimated from the ratio.

FIG. 3 is a graph showing the relationship between the culture period and the numbers of viruses, bacteria and flagellates in Sample 4. FIG.
As can be seen from the figure, the number of flagellates increased by about two orders in one day of culture, but the number of viruses did not decrease. In addition, no decrease in the number of viruses was observed even after 2 days of culture and further after 7 days of culture. The same result was obtained for sample 3. From the results of Samples 1 and 2 to which ciliates were added and the results of Samples 3 and 4 to which flagellates were added, it was found that ciliates were effective in removing viruses.

The state of predation of ciliates is to take up food by using many cilia, and it is considered that viruses are simultaneously taken up by the cilia during this incorporation.

<Experiment 2: Virus reduction rate and ciliate ( Cili
ate No.9 ) Examination of the relationship with the population> In the same manner as in Experiment 1 above, artificially treated water was inoculated with ciliates, and P.fl
The ciliate population was controlled by adding or controlling the amount of orescence (feed), and sample solutions of various numbers of solids were prepared. In addition, Ciliate No. 9 (membrane: length 3)
0 to 50 μm, width 5 to 15 μm). After culturing this for 2 days, the RNA phage Qβ2 × 10 ⁶ P
FU / ml was added, the cells were further cultured for 24 hours, and the number of viruses (phages) and the number of ciliates were measured. The measurement method is the same as the above experiment
Is the same as Table 3 shows the results.

[0040]

[Table 3]

As can be seen from Table 3, the larger the ciliate population, the smaller the number of remaining viruses. Therefore, it can be seen that increasing the number of ciliates is effective in increasing the virus removing effect.

<Experiment 3: Examination of virus removal effect by various ciliates> As ciliates, Colpoda sp ( Coleoptera : length 40 to 80 μm, width 35 to 50 μm), Ciliate No. 2
(Epitope: length 30-60 μm, width 10-20 μm),
Oxytricha sp (under hair: length 150μm, flat shape),
And Ciliate No. 9 were used. Wash these ciliates,
Each was inoculated into 10 ml of the above-mentioned artificial secondary treatment water, and P.
1 × 10 ⁹ florescence were added, and E. coli RNA phage Qβ was further added as a virus. Table 4 below shows the number of viruses immediately after the addition (day 0 of culture). These are cultured in a thermostat at 25 ° C. for 3 days with shaking.
The number of ciliates and the number of viruses were measured. In addition, these measuring methods were performed by the same method as the above-mentioned experiment 1, and only those in the active state were measured for ciliates except those that formed cysts. Table 4 shows the results.

[0043]

[Table 4]

As can be seen from Table 4, in the case of Ciliate No. 9 , the number of viruses was very low, but Colpoda sp , Cili
In the case of ate No.2 and Oxytricha sp , the virus hardly decreased. Oxytricha sp grows slowly,
The handleability was poor. Also Colpoda sp and Ciliat
e Microscopic observation of No. 2 revealed that the cyst was secreted to the body surface to form a cyst.

FIG. 4 shows the ciliateCiliate No.7(Membrane eyes),
Ciliate No.9,Ciliate No.2,Colpoda spabout,P.
florescence Graph showing the maximum growth number when feeding
It is. As can be seen from FIG.Ciliate No.7AndCiliate
No.9Is the bait (P.florescenceCilia) as ciliata grow
The number is increasing. on the other handCiliate No.2Has relatively little food
When there is no food, the number of ciliates increases as the food increases.
But the food is 10 ^TenWhen the amount becomes large like CFU / ml,
The number of ciliates is rapidly decreasing. AlsoColpoda spThen
Ciliate numbers are almost constant when food is relatively low
However, the ciliate count sharply decreased when the food was large.
Ciliate No.2,Colpoda spIs greater than the maximum density
Then form a cyst, even if there is a lot of food
It does not exceed a certain number.

As described above, depending on the type of ciliate, a cyst is formed for the preservation of the species when the number exceeds the maximum number of living individuals (density). It is considered that the ciliate was dormant and did not remove the virus, and as a result, the virus did not decrease as shown in Table 4 above.

Therefore, in the case of ciliates which form cysts as described above, even if the number of ciliates is increased for the purpose of enhancing the virus removal effect, the virus removal effect is rather reduced, so that in actual operation, It is not suitable because virus removal cannot be performed efficiently.

On the other hand, since Ciliate No. 9 does not form cysts, the number of ciliates in the active state can be increased. Therefore, the virus removal ability can be enhanced by the increase in the number of ciliates, and the virus can be effectively removed. Can be performed. Species that do not form cysts, such as Ciliate No. 9 above, are ciliates of the order Membrane, so virus removal is performed using the ciliates of the order Membrane.

<< Example of Virus Removal Device >> As described above, increasing the individual density of ciliates is effective for virus removal. Therefore, a virus removal device having a region where ciliates live in high density will be described below. Will be described.

<Embodiment 1> FIG. 5 is a schematic sectional view showing an example of a virus removing apparatus. The column 1 is filled with a porous carrier 2, and an inlet 3 through which water to be treated flows in and an air inlet 5 through which air flows are provided upstream of the column 1. Is provided with an outlet 4 for discharging treated water and an air outlet 6 for discharging air. The inlet 3, outlet 4, air inlet 5, and air outlet 6 are provided with valves 3a, 4a, 5a, 6a, respectively, to control the inflow and outflow. In addition to the case where the treatment is performed by continuously flowing the water to be treated, the valves 3a, 4
By stopping a, the water to be treated can be treated in the column 1 in a batch system. In addition, the inflow and outflow of air are adjusted according to the nature of the ciliate used.

FIG. 6 is an enlarged sectional view showing the surface of the porous carrier 2. The porous carrier 2 has a large number of holes 2a having a diameter of 50 to 500 µm, and ciliates (10 to 100 µm in size) are settled in the holes 2a and on the surface of the carrier 2. When the water to be treated flows into the column 1, bacteria and viruses present in the water to be treated are eaten and removed by the ciliates resident on the porous carrier 2.

Since the virus removing device provided with the porous carrier as in Example 1 can inhabit a large number of ciliates of the order of the membrane, it can be treated continuously instead of in a batch system. In addition, many viruses can be removed from the water to be treated.

<Embodiment 2> FIG. 7 is a schematic sectional view showing another example of the virus removing apparatus. The membranes 11a and 11b are provided on the inflow side 13 and the outflow side 14 of the water to be treated of the column 10, respectively. The membranes 11a and 11b have pores, the pore size of which is larger than viruses and bacteria and smaller than the above ciliates. The pore size may be appropriately selected depending on the size of the ciliate.

By being sandwiched between the membranes 11a and 11b, the ciliates are confined in the inside thereof and live in high density without flowing out of the column 10. When water to be treated is passed through the high-density area of the ciliates, viruses and bacteria are predated and removed by the ciliates, and purified water is released from the outflow side 13.

[0055]

According to the present invention, virus is removed from the water to be treated using ciliates of the order Membrane, so that a large amount can be treated by a simple system without adversely affecting the discharge destination. In addition, the maintenance cost for the processing equipment and its operation is low, and the virus can be removed with high removal efficiency. Since the present invention can remove not only human viruses but also viruses harmful to plants, livestock, fish, and the like, the treated water can be used as recycled water in the livestock industry, agriculture, and fisheries.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the culture period and the number of viruses, bacteria, and ciliates when ciliates were added.

FIG. 2 is a graph showing the relationship between the number of viruses and the culture period when ciliates were added.

FIG. 3 is a graph showing the relationship between the culture period and the numbers of viruses, bacteria, and flagellates when flagellates are added.

FIG. 4 is a graph showing maximum growth numbers for various types of ciliates.

FIG. 5 is a schematic sectional view showing Example 1 of the virus removal device according to the present invention.

FIG. 6 is an enlarged sectional view showing a surface portion of a porous carrier in Example 1.

FIG. 7 is a schematic sectional view showing Embodiment 2 of the virus removal device according to the present invention.

[Explanation of symbols]

 1, 10 column 2 porous carrier 3 inlet 3a, 4a, 5a, 6a valve 4 outlet 5 air inlet 6 air outlet 11a, 11b membrane 13 inflow side 14 outflow side

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Shintaro Suzuki 1-3-18 Wakihama-cho, Chuo-ku, Kobe Kobe Steel Ltd. Kobe Head Office

Claims (5)

[Claims] 1. A method for removing a virus, comprising passing treated water through a region where ciliates of the order Membrane are present. 2. It comprises an area where ciliates of the order Membrane are present,
A virus removal device, comprising: an inlet for inflowing water to be treated into the region, and an outlet for discharging treated water from the region. 3. The method according to claim 3, wherein the ciliate is present in a region having a diameter of 50.
The virus removal device according to claim 2, further comprising a porous carrier having a hole diameter of about 500 µm. 4. The virus removing apparatus according to claim 2, wherein the area where the ciliates are present is surrounded by a membrane having a larger pore size than viruses and bacteria and smaller than the ciliates. 5. The virus removal device according to claim 4, wherein a region surrounded by the membrane is exchangeable.