JPS62298498A - Method for preventing pollution of marine organisms by injection of deposited phage - Google Patents

Abstract

PURPOSE:To efficiently prevent the pollution due to marine organisms by propagating the bacteriophage which cause bacteriolysis the pollutive microorganisms sticking to sponge balls in liquid contg. the sponge balls and supplying such sponge balls to a device utilizing the sea water. CONSTITUTION:The bacteriophage which cause bacteriolysis the pollutive microorganisms sticking to the sponge balls is propagated in the liquid contg. the sponge balls in a phage culture tank 9, in a method for cleaning the device 4 utilizing the sea water with the sponge balls. Such sponge balls or the bacteriophage liquid contg. the sponge balls is supplied to the device 4 utilizing the sea water. As a result, the pollution due to the marine organisms for the device utilizing the sea water is efficiently and economically prevented.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention is directed to the cooling of equipment that uses seawater for cooling, such as coastal power plants, and other equipment that uses seawater for cooling. Concerning recovery, cooling equipment, and L method.

[Conventional technology]

The conventional technology will be explained below with reference to FIG. 3, taking a thermal power plant as an example.

Intake water (ocean) 1 obtained from the intake area is filtered by screen equipment 2 to remove solid matter such as seaweed and shellfish, and then sent to a condenser 4 by a heavy water pump 3. After heat exchange, it passes through a ball collector 5. It is discharged into the discharge area as discharge water 6. Usually, in a thermal power plant, a system consisting of one or several condensers is provided for one boiler.

In the operation of such a seawater system, Fujibbo oysters,
Large organisms such as shellfish such as mussels, insects such as bulrushes, and microorganisms such as bacteria are present on the water intake side walls, pipe inner walls,
Preferably grows in the water chamber of a heat exchanger. The adhesion process of these fouling organisms is: ■ Attachment of bacteria to the surface of the structure, ■ Increase in the biofouling film due to proliferation of attached bacteria and formation of extracellular slime biofouling film, and ■ Attachment of various plankton and It is thought that the process progresses through the adhesion and growth of the larvae of the large molluscs that feed on it, with the adhesion of bacteria playing a major role.

The phenomenon caused by the adherent growth of the above-mentioned fouling organisms not only causes an increase in head loss in the seawater system, but also causes blockage of equipment and branch pipes,
It also causes blockage of the condenser and condenser tubules, and destruction of the protective coating inside the tubules, promoting erosion and local corrosion.

Conventionally, the following methods have been known as means for solving such problems.

(1) Chlorine, ozone, bromine, bromine chloride, hydrogen peroxide, permanganate, arsenate, arsenite, cyanide,
A method in which antifouling agents containing compounds such as metal salts, organometallic compounds, and phenols are mixed directly into the water intake or applied to the surface of structures to kill attached organisms.

method, ultrasonic vibration method, mechanical cleaning method using a sponge ball or brush.

(3) A combined method of (1) and (2) above.

Note that cleaning the condenser 4 shown in FIG. 3 with a sponge ball is performed as follows. Usually, this is carried out with seawater flowing through one of the plurality of condensers 4.

First, as shown in FIG. 3, the sponge balls 10 are supplied to the pole collector 8. The initial supply amount of sponge balls 10 is 10 to 20, which is the number of cooling pipes per pass of the condenser 4.
It is about φ. Thereafter, the amount of sponge balls 10 to be supplemented is replenished by the uncollected portion of the initial supply amount, and the total amount is updated periodically. After the sponge balls 10 are immersed in the pole collector 8 to contain water, the pole collection valve 14 and the pole circulation valve 15 are opened, and the circulating water pump 7 is operated to supply the sponge balls to the condenser 4. do. As shown in FIG. 2, the sponge balls 10 introduced into the condenser 4 through the circulation valve 15 first enter the cooling water chamber 20. Then, the sponge balls 10a and 10b are pushed away in the direction of the water flow while rubbing against the inner wall of the cooling pipe 18 by the water pressure and water flow. The sponge balls 10 that have passed through the cooling pipe 18 exit the condenser 4 and enter the pole collector 5 where they are separated from the effluent water 6, and then go through the pole collection valve 14 and the circulating water pump 7 to the pole collector 8. Sent. The above operations are continued for a predetermined period of time to circulate the balls. The slime generated on the inner wall of the cooling pipe 18 of the condenser 4 in this way is periodically removed by the sponge ball 10. Normally, iron salt is injected into the condenser 4 to form a thin protective film on the inner wall surface of the cooling pipe 18 to prevent corrosion caused by seawater. The sponge ball 10 is also used to remove the dirt. When the cleaning is completed, the pole collection valve 14, the ball circulation [Problem to be solved by the invention] In the method (1) above using an antifouling agent, the antifouling agent is expensive and does not cause biological fouling. Since it is also toxic to unrelated marine organisms, its use is restricted from the standpoint of environmental conservation. Additionally, if some antifouling agents are regularly used, K may accumulate in the bodies of marine organisms, potentially causing secondary pollution.

In method (2) above, the mechanical cleaning method using a brush is used to remove shellfish from water intake side walls, the inner walls of large-diameter pipes, and the inner walls of heat transfer tubes in heat exchangers, while the mechanical cleaning method using sponge balls is This method is only used to remove slime from exchanger ice chambers and thin tubes; other methods are impractical in terms of cost and antifouling effect. In addition, the mechanical cleaning method using a sponge ball is
If the number of cleanings is too high, it will damage the surface of the structure and cause corrosion, but if the number of cleanings is too small, the removal of fouling microorganisms will be insufficient and they will grow on the surface, and eventually large-scale fouling organisms will grow and be used from the ground. On the other hand, it has become difficult to deal with this problem because it is not possible to increase the number of times the sponge ball is washed, and the emergence of an antifouling agent to replace it has been awaited.

[Means for solving problems]

A large amount of the fouling microorganisms scraped from the inside of the cooling pipe by cleaning the sponge ball remains in the pores of the ball, and the ball becomes an ideal breeding ground for the fouling microorganisms.

The present invention utilizes this to solve the above-mentioned problems, and aims to proliferate bacterium phages that lyse the fouling microorganisms remaining on the balls, and thereby Alternatively, the bacteriophage is adsorbed to newly grown fouling microorganisms and lysed. The present invention solves the problem of cleaning the sponge balls by a method of cleaning them in the process of studying the practical application of the basic invention related to the earlier application (see Japanese Patent Application Laid-open No. 159596/1983). A supported phage characterized in that a bacteriophage that lyses sexual microorganisms is grown in a solution containing the sponge balls, and then the sponge balls or the bacteriophage i containing the sponge balls are supplied to an apparatus that uses seawater. This relates to a method for preventing marine biofouling due to injection.

[Effect]

In the present invention, the bacteriophage carried on a sponge ball and injected has the effect of lysing and sterilizing fouling microorganisms, so that the fouling microorganisms remaining or newly attached to the surface of the structure are involved in biological fouling. Only the attached microorganisms that are attached are treated as specific.

Furthermore, the present invention can sufficiently remove attached microorganisms without damaging the surface of the structure, and since the present invention uses bacteriophage, a natural product that already exists in nature, it does not cause secondary pollution due to accumulation. do not have.

〔Example〕

Next, specific embodiments of the present invention and their specific effects will be described.

1 Embodiment FIG. 1 is a flowchart showing an example of an embodiment of the present invention, and the condenser 4 in FIG. 1 has the same configuration as in FIG.
Water intake (seawater) in the diagram 1. Screen equipment 2. Water intake pump 3. Condenser 4. Pole collector 5. Effluent water6. Pole collector8. Sponge ball 10. Ball collection valve 14. The pole circulation valve 15 has the same structure as that shown in FIG.

Initially, 1° of sponge balls used for cleaning are collected in a collection device 8 in one of the plurality of condensers 4 provided. After cleaning, ball collection valve 14, ball circulation valve 1
5 is closed to stop the circulation pump 7. Next, the ball recovery valve 16 is opened and the sponge ball 1o used for washing is sent to the phage culture tank 9 together with seawater. The phage culture tank 9 is first supplied with a nutrient source 13 and sterile air 12.

The nutrient source 13 may have a composition suitable for the growth of marine heterotrophic bacteria, and is usually yeast extract and polypeptone with a content of Q, 001-llL1wt% and cLo0, respectively.
5 to [lL 5wt%. However, if the seawater temperature in the water intake area of water intake (seawater) 1 is relatively high and the nutrients such as organic matter are relatively high, or if the interval between sponge ball cleaning operations is sufficient, the nutrient source 13
does not need to be added.

After 4-24 hours, preferably 6-8 hours, seed phage 11 is added.

As the seed phage 11, a previously searched bacteriophage that lyses staining microorganisms present in the intake water (seawater) 1 is used. Thereafter, the liquid in the phage culture tank 9 containing the sponge balls 1o is heated to 30% by sterile air 12.
Stir for more than a minute, but this operation can also be continued at the start of the next sponge ball cleaning operation.

In addition, the amount of bacteriophage added is 1010 to 10 for a bacterial concentration of 108 cells/L like normal seawater.
The concentration should be 6 pieces/l, preferably 109 to 107 pieces/l.

The sponge balls 10 thus obtained are supplied together with the liquid in the phage culture tank 9 in place of the sponge balls 10 used in the conventional cleaning method by opening the ball supply valve 17 during the next sponge ball cleaning. . The sponge ball cleaning time is about the same as in the prior art. After cleaning, the sponge balls are again sent to the 7-age culture tank 9 via the ball recovery valve 16 in the manner described above.

Further, in the present invention, only the phage-carrying sponge balls 10 obtained as described above can be supplied (separated from the liquid in the tank 9).

2. Effect (1) When the sponge ball is initially cleaned, a large amount of the fouling microorganisms scraped from the inner wall surface of the cooling tube remains in the pores of the sponge ball 10.

[2) Sponge ball 10 containing fouling microorganisms
By stirring the sterile air 12 together with seawater in the phage culture tank 9, the fouling microorganisms grow within the pores of the sponge ball 10. If the nutrient source 13 is added, the amount of growth can be further increased.

(3) Bacteriophage (or simply “phage”)
) are also called bacterial viruses, and are composed only of nucleic acids and proteins and do not have the ability to self-replicate. It has the effect of parasitizing certain bacteria and lysing them. More specifically, a phage propagates after it attaches to a bacterium, injects the phage nucleic acid into the bacterium, synthesizes the phage nucleic acid and protein within the bacterium, and then forms a phage particle. Bacteria are lysed and several dozen new
It occurs through a process of releasing hundreds of phages.

In the present invention, the seed phage 11 is adsorbed by the fouling microorganism in the growth phase within the pores of the sponge ball 10, and then the phage is released when the fouling microorganism is lysed. The released phage further lyses the remaining fouling microorganisms, and in this way, most of the fouling microorganisms are lysed, and the released phages are suspended not only in the 1° pores of the sponge ball but also in the liquid of the phage culture tank 9. do.

(4) By injecting the phages contained in the liquid of the phage culture tank 9 into the condenser 4, the phages are adsorbed to the fouling microorganisms contained in the intake water (seawater) 1,
This is lysed.

(5) When the sponge ball 102>f passes through the cooling pipe 18, contaminating microorganisms that adhere to the inner wall surface during the sponge ball cleaning stop period or that were not removed during the previous cleaning are removed using the conventional method. It is scraped off and removed by the sponge ball 10 in exactly the same way. At this time, the spherical sponge ball 1° is distorted into a flat shape like the sponge ball 10b, and as a result, the phages present in the pores leak into the gap between the inner wall surface of the cooling tube 18 and the sponge ball 101). However, it adsorbs and lyses staining organisms that were not removed even by the above-mentioned scraping process.

(6) After cleaning, the pores of the sponge ball 1o contain newly removed contaminating microorganisms, as in the case after the previous cleaning.

〔Effect of the invention〕

(1) The pores of the sponge ball 10 are suitable for the growth of the fouling microorganisms scraped from the inner wall surface of the cooling tube 18, and a large amount of bacterial cells can be obtained, thereby obtaining a large amount of phages.

12) The lytic effect of phages (lysis time, amount released) is highest when the staining microorganism to be lysed is in the growth phase. In the phage culture tank 9, the seed phage 11 adsorbs and lyses the fouling microorganisms in the growth phase in the pores of the sponge balls 10, thereby obtaining the greatest bacteriolytic effect.

This allows a large amount of phage to be obtained efficiently.

(3) The efficiency with which phages are adsorbed to fouling microorganisms is proportional to the product of their respective concentrations. Therefore, water intake (seawater) 1
If the concentration of fouling microorganisms supplied is constant, it is necessary to increase the injection concentration of phages as much as possible.

In particular, since fouling microorganisms adhere to the inner wall surface of the cooling tube 18, it is necessary to increase the phage concentration near the wall surface. In the present invention, when the sponge pole 10b passes through the inside of the cooling pipe 18, a high concentration of phage is leached onto the wall surface of the cooling pipe 18, so that together with the scraping by the sponge pole 10b, the phage can be efficiently adsorbed to the fouling microorganisms. Also,
Once a phage adsorbs to a fouling microorganism, it will eventually lyse and die, even if the time required for lysis varies.

(4) After cleaning the sponge ball, use the sponge pole 10
Using the fouling microorganisms contained within the pores of the phage, a large amount of phages required for the next cleaning operation can be obtained.

In combination with the above effects, the following effects occur.

(5) The type of staining microorganism changes depending on the season, and the type of seed phage 11 must also be changed accordingly, but this can be quickly dealt with by observing the growth status of the seed phage 11 on the sponge pole 10.

(6) Since staining microorganisms are sufficiently lysed and removed, not only does it eliminate excessive cleaning of the sponge ball, but also
The number of washings can be reduced.

(Power) It is possible to prevent the adhesion of bacteria to the structure surface at the earliest stage of the adhesion process of fouling organisms.
Subsequent adhesion and growth of large contaminants can be prevented.

[Brief explanation of drawings]

Fig. 1 is a flow diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing the behavior of a sponge pole in a capillary according to the present invention and a conventional method;
FIG. 3 is a flowchart showing a conventional method. 1...Water intake (seawater), 2...Screen equipment, 6.
... Water intake pump, 4 ... Condenser, 5 ... Ball collector, 6 ... Discharge water, 7 ... Circulating water pump, 8 ...
Ball collector, 9...phage culture tank, 10, 10a
, 10b... sponge pole, 11... seed phage, 12... sterile air, 13... nutrient source, 14...
Ball collection valve, 15... Ball circulation valve, 16... Ball recovery valve, 17... Ball supply valve, 18... Cooling pipe, 19... Partition wall, 20... Cooling water chamber, 21...
Cooling pipe room diagram 2

Claims (1)

[Claims] In a method for cleaning sponge balls of equipment using seawater, bacteriophages that lyse fouling microorganisms attached to the sponge balls are grown in a solution containing the sponge balls, and then the sponge balls or the sponge balls are cleaned. A method for preventing marine biofouling by injecting supported phage, which comprises supplying a bacteriophage solution containing the phages to a device that uses seawater.