JP2009207986A - Method for suppressing propagation of algae in sewage treatment water and device therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for suppressing the propagation of algae in a closed water area and a device therefor which can inexpensively suppress the propagation of algae without taking effort. <P>SOLUTION: A biological reaction tank 2 having screens 21, 22 where the inflow or outflow of water is possible at the upper part and the lower part, and storing microorganism holding carriers S capable of carrying microorganisms is installed in the vicinity of the surface layer of a closed water area, the biological reaction tank 2 is aerated from the lower part with an aeration means 3, a mild rising stream is generated at the inside of the biological reaction tank 2, a mild lowering stream is generated at the outside of the biological reaction tank 2, further, the microorganism holding carriers S are fluidized, and the operation is continued, thus, trace metal oxidizing microorganisms oxidizing trace metals required for the propagation of algae are carried on the surfaces of the microorganism holding carriers S spontaneously, and, by the trace metal oxidizing microorganisms carried on the microorganism holding carriers S, trace metals included in the water of the closed water area made to flow in from the lower part of the biological reaction tank 2 are oxidized and insolubilized, thus the oxidized trace metal oxides are settled by the lowering current. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for suppressing the growth of algae in a closed water area such as a dam reservoir.

  When polluted water flows into closed water areas such as dam reservoirs and lakes, the concentration of nutrients (compounds such as phosphorus and nitrogen) in the closed water areas increases and eutrophication occurs. Algae may be generated in large quantities. When a large amount of algae occur in such a closed water area, it itself is a landscape obstacle, and when algae are launched on the shore and decays, it gives off a foul odor, or the water area is used as a source of tap water. There is a problem that it has a strange odor.

  In order to solve such problems, conventionally, aeration circulation is carried out near the bottom of lakes such as dam reservoirs, etc., and water warming layers (relatively hot and low-density water areas heated by solar radiation and deeper relatively It is a boundary with low-temperature and high-density water areas, and it is a layer where there is a large density difference and water exchange between these water areas hardly occurs, and the surface water temperature is lowered and algae is drawn deeper than the light layer. Therefore, suppression of abnormal growth of algae has been performed. However, there are many examples where a large-scale apparatus is required, the equipment cost is high, and sufficient effects are not achieved.

  Patent Document 1 discloses a method for removing sea cucumber by spraying a biodegradable plastic carrier on which microorganisms having the ability to dissolve and agglomerate the sea bream are immobilized. However, in the method for removing sea cucumber described in Patent Document 1, although it is biodegradable, a plastic carrier is added directly to a closed water area, causing secondary pollution to the environment and disturbance of the ecosystem. There is a problem of end.

  Patent Document 2 has a decomposition treatment tank that is installed in surface water in a closed water area and is filled with a bottom mud immobilization support that supports microorganisms on its surface, and is aerated by an aeration device from the lower part of the decomposition treatment tank. A treatment apparatus for cyanobacteria and microcystin that suppresses abnormal growth of cyanobacteria and microcystin generated in the closed water area is described. The treatment apparatus for cyanobacteria and microcystin described in Patent Document 2 selects and immobilizes effective microorganisms on a carrier for supporting microorganisms, as in the method for removing blue-green leaves described in Patent Document 1, There is a problem that it is necessary to collect the sample and immobilize it on each carrier, which takes time. There is also a problem that the effect is not sufficient.

JP 2000-254686 A JP 2005-205336 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problems of the conventional techniques described above, and to provide a method for suppressing algal growth in a closed water area and a device therefor which can suppress the growth of algae at low cost without taking time. .

  In order to solve the above-mentioned problem, the invention described in claim 1 is a method for suppressing the growth of algae in a closed water area such as a dam reservoir, and has a screen capable of inflow or outflow of water at an upper part and a lower part. A biological reaction tank containing a microorganism-supporting carrier capable of supporting microorganisms is installed near the surface layer of the closed water area, and the biological reaction tank is aerated from below by aeration means, and is gently placed inside the biological reaction tank. A micro metal oxide microorganism that oxidizes a trace metal necessary for the growth of algae by generating a gentle downward flow on the outside of the bioreactor with an upward flow and continuing to fluidize the microorganism holding carrier. Included in the water of the closed water area that is naturally supported on the surface of the holding carrier and is introduced from the lower part of the biological reaction tank by the trace metal oxidation microorganisms supported on the microorganism holding carrier. Serial trace metals oxidized to insolubilize the, and wherein the precipitating trace metal oxide oxidized by the trace metal oxide microorganism by the downflow.

  Invention of Claim 2 is an apparatus used for the algal growth suppression method in the closed water area of Claim 1, Comprising: It has a screen which can inflow or outflow of water in the upper part and the lower part, and carries microorganisms A biological reaction tank containing a possible microorganism-supporting carrier; an aeration unit that is connected to the lower part of the biological reaction tank at a predetermined interval and aerated by sending air; and a connection that suspends the biological reaction tank to a predetermined depth And a water surface moving means capable of moving around the water surface of the closed water area.

  The invention described in claim 3 is characterized in that, in claim 2, the microorganism holding carrier is made of a resin having a specific gravity of about 1.

  The invention according to claim 4 is the invention according to claim 2 or 3, wherein the length of the connecting member can be adjusted, and the installation depth of the biological reaction tank can be changed according to the depth of the water temperature climbing layer. It is characterized by becoming.

  As described above, the invention according to claim 1 has a biological reaction tank having a screen capable of inflowing or outflowing water at the upper and lower portions and containing a microorganism holding carrier capable of supporting microorganisms. Installed in the vicinity of the surface layer, aerating means aerate the biological reaction tank from below, generating a gentle upward flow inside the biological reaction tank and a gentle downward flow outside the biological reaction tank, and holding the microorganism A trace amount of metal oxidation microorganisms that oxidize trace metals necessary for algae growth by allowing fluidization of the support to be naturally supported on the surface of the microorganism support carrier, Trace metals oxidized by the trace metal oxidation microorganisms by oxidizing and insolubilizing the trace metals contained in the water of the closed water area introduced from the lower part of the biological reaction tank by the metal oxidation microorganisms Since precipitate the product in the downflow, trace metals required for growth of algae and other soluble manganese algae in a state that can not intake, it is possible to significantly reduce the algae growth potential of the closure body of water. Therefore, a large amount of algae in summer can be surely prevented, and problems such as landscape obstacles, bad odors and off-flavors can be solved. In addition, no labor is required and the equipment and operating costs are low.

  The invention described in claim 2 has a biological reaction tank having a screen capable of inflow or outflow of water at the upper part and the lower part and containing a microorganism holding carrier capable of supporting microorganisms, and a predetermined part below the biological reaction tank. Aeration means connected at intervals and aerated by sending air; and a water surface moving means having a connecting member for suspending the biological reaction tank to a predetermined depth and capable of moving in the vicinity of the water surface of the closed water area. Because it is equipped, it can easily move to the whole closed water area or a specific place with water surface moving means, biological treatment, settle the trace metals necessary for algae growth and make it impossible for algae to ingest, The algal growth potential of the place to be suppressed can be greatly reduced. Therefore, a large amount of algae in summer can be surely prevented, and problems such as landscape obstacles, bad odor, and off-flavor can be solved. In addition, no labor is required and the equipment and operating costs are low.

  The invention according to claim 3 is that in claim 2, since the microorganism holding carrier is made of a resin having a specific gravity of about 1, in addition to the above effects, the microorganism holding carrier can be fluidized more effectively, Biological reactions of trace metal oxidizing microorganisms can be promoted. For this reason, it is possible to efficiently oxidize trace metals in a short period of time.

  The invention according to claim 4 is the invention according to claim 2 or 3, wherein the length of the connecting member can be adjusted, and the installation depth of the biological reaction tank can be changed according to the depth of the water temperature climbing layer. In other words, since the depth of the water temperature change layer and the thickness of the water temperature change layer that changes with the change of the season can be changed, the surface layer above the water temperature increase layer in the closed water area Trace metals contained in water can be efficiently oxidized. For this reason, the growth of algae can be efficiently suppressed in a short period of time.

  An embodiment of the present invention will be described with reference to the drawings.

First, an embodiment of the algal growth suppression device according to the present invention will be described with reference to FIGS.
FIG. 1 is a configuration explanatory diagram showing a schematic configuration of an algal growth suppression device according to an embodiment of the present invention, and FIG. 2 is a photograph of a microorganism holding carrier according to an embodiment of the present invention. Reference numeral 1 in FIG. 1 is an algae growth suppression device, and this algae growth suppression device 1 is mainly composed of a biological reaction tank 2, an aeration means 3, and a trolley 4 which is a water surface movement means. This device suppresses the growth of algae in a closed water area such as a reservoir.

  This biological reaction tank 2 is mainly composed of a cylindrical reaction tank main body 20 having an opening at the top and bottom, and is similar to a screen 21 that allows inflow and outflow of water without passing through a microorganism holding carrier S described later on the upper part. It has a screen 22 that allows the inflow / outflow of water without passing through the microorganism holding carrier S in the lower part, and is configured to allow water to flow in from the lower part and outflow from the upper part. It is installed at a depth of about half of the depth of water, that is, at a depth approximately in the center of the surface water. The screens 21 and 22 are preferably made of stainless steel in consideration of corrosion resistance. Further, in this biological reaction tank 2, a microorganism holding carrier S capable of supporting microorganisms is accommodated.

  The microorganism holding carrier S is not particularly limited in shape and material as long as it has a certain degree of unevenness so that microorganisms can easily adhere to the surface and can be easily fluidized by air aeration. As shown in FIG. 2, the resin is molded into a hollow cylindrical shape and adjusted so that the specific gravity is about 1. As described above, since the microorganism holding carrier S according to the present embodiment is formed in a hollow cylindrical shape, the surface area can be increased as compared with the volume. The reaction can be promoted. Further, since it is made of a resin having a specific gravity of about 1, it can be easily fluidized simply by aeration from the bottom.

The aeration means 3 is mainly composed of a diffuser plate 30, a pressure feeding pipe 31 that is a pneumatic feeding means, and a compressor 32, and is connected to a lower part of the biological reaction tank 2 by a plurality of fixing rods 33 at a predetermined interval. ing. Air is fed into the diffuser plate 30 from the compressor 32 which is the pneumatic feeding means of the aeration means 3 through the pressure feeding pipe 31, and the biological reaction tank 2 is aerated from below, and as shown by the arrows in the figure, the biological reaction tank A gentle upward flow is generated inside 2 and a gentle downward flow is generated outside the biological reaction tank 2. Further, the microorganism holding carrier S accommodated in the biological reaction tank 2 is fluidized by the aeration of the aeration means 3 and uniformly contacts the water in the closed water area. For this reason, the water of a closed water area can be processed by the biological reaction by the microorganisms to carry.
Note that the length of the fixing rod 33 may be adjusted in consideration of maintenance or the like.

  By the way, it is conventionally known that there are trace metal oxidizing microorganisms that oxidize trace metals (for example, manganese Mn) necessary for algae growth. However, these trace metal oxidation microorganisms have a slow growth rate, and in a floating state, they cannot grow in large quantities even in closed water areas such as dam reservoirs. However, as described above, by installing the biological reaction tank 2 containing the microorganism holding carrier S and continuing aeration with the aeration means 3 from below, that is, fluidizing for a certain period under aerobic conditions. By continuing, the trace amount metal-oxidized microorganisms can adhere and grow on the surface of the microorganism-supporting carrier S.

  The trolley 4 is a general ship that is maneuvered by a person, but is exemplified as an embodiment of the water surface moving means, and only hangs the biological reaction tank 2 and the aeration means and stays near the water surface. It only needs to have buoyancy, drive means such as an engine or motor, and propulsion means such as a submersible screw or propeller, so that it can be moved to a predetermined location on the surface of a closed water area. It may be possible to steer from remote locations such as shores with possible underwater screws and floats, or it will move automatically over the water surface by the program and move across the water surface of the closed water area for processing. May be.

  This barge 4 has a plurality of variable fixing rods 40 as connecting means for connecting the barge 4 and the reaction tank body 20 of the biological reaction tank 2, and the biological reaction tank 2 has a predetermined depth, that is, a water temperature. It is designed to be hung to about half the depth of the water layer. Further, the length of the variable fixing rod 40 can be adjusted, and the installation depth of the biological reaction tank 2 can be changed according to the water depth of the water warming layer that changes according to the season.

  Next, the water temperature climbing layer will be described with reference to FIG. FIG. 3 is an explanatory diagram showing the installation positions of the water temperature climatic layer and the algal growth suppression device. As described in the background art, the water temperature striking layer is a relatively high temperature and low density water area (surface water) heated by solar radiation and deeper than that, that is, a relatively low temperature deeper than the light layer. This is a boundary (interface layer) with a high-density water area, and the water temperature changes abruptly in this layer as shown in the change curve of the water temperature depending on the water depth in the figure. For this reason, there is a large density difference between the two water areas, and there is almost no exchange of water between these water areas, that is, convective circulation of water does not occur across this layer. Naturally, the water temperature rises in different regions, but in Japan, it begins to form in early spring when the temperature is generally high and the solar radiation is strong, reaches the deepest in summer (about 5m), and disappears in late autumn.

Next, operation | movement of the algal growth suppression apparatus 1, ie, embodiment of the algal growth suppression method in the closed water area which concerns on this invention is demonstrated using FIG.
First of all, in the spring, the boat 4 moves to a predetermined position in the closed water area where the growth of algae is a concern. Then, the length of the variable fixing rod 40 is adjusted, and the water temperature rises from the water surface without destroying the water temperature rise layer. The biological reaction tank 2 (and the aeration means 3) is installed so as to be approximately in the center of the surface water up to the layer (see FIG. 3). Thus, when it is installed in the approximate center of the surface water, the trace metals contained in the surface water can be efficiently oxidized and insolubilized.

  Next, the aeration means 3 is continuously operated for a certain period, and the microorganism holding carrier S in the biological reaction tank 2 is continuously fluidized for a certain period under an aerobic condition, whereby a trace metal oxidation microorganism having a relatively slow growth rate ( For example, a microorganism that oxidizes soluble manganese and insolubilizes it) is naturally supported on the surface of the microorganism-supporting carrier S.

  Then, the trace metal contained in the water flowing in the direction of the arrow in FIG. 1 is oxidized and insolubilized by the biological reaction of the trace metal oxidizing microorganism. The insolubilized trace metal oxide gradually aggregates and gradually becomes large particles.

When the operation of the aeration means 3 is continued, as shown by the arrows in FIG. 1, a gentle upward flow is generated inside the biological reaction tank 2 and a gentle downward flow is generated outside the biological reaction tank 2, that is, in the surface water. A quiet flow is generated that circulates through In addition, since the specific gravity of the trace metal oxide is heavier than that of water, when the trace metal oxide particle size is about 1 μm, the trace metal oxide is gradually settled on the downward flow. In addition, since this flow is very gentle, when the trace amount of metal oxide particles reaches the lower end of the flow, it escapes from the flow and settles over the water temperature crushing layer as it is.
As mentioned above, water does not circulate beyond the water temperature layer, so if the trace metals contained in the surface water are almost oxidized and insolubilized, algae that grow using photosynthesis are necessary for growth. Trace metals such as soluble manganese cannot be ingested, and as a result, they cannot be generated greatly.

  As described above, according to the method for suppressing algal growth in a closed water area according to the present embodiment, the biological reaction treatment is not performed on the total amount of water in the closed water area such as a dam reservoir as in the prior art, but the surface layer. Since only water is targeted, the potential for algae growth in surface water can be reduced by reducing the concentration of trace metals required for algae growth in a concentrated and quick manner in the most algae-prone waters. Can be reduced. For this reason, a large amount of summer algae can be reliably prevented in a closed water area, and problems such as landscape obstruction, bad odor, and off-flavor can be solved. In addition, the labor and labor for selecting and immobilizing microorganisms are not required, and the equipment and operating costs are low.

(Effect confirmation experiment)
In order to confirm the algal growth inhibitory effect of the algal growth suppression method in the closed water area of the present invention, the following experiment was conducted in the inflow river of the dam reservoir (Miharu dam) where abnormal algal growth is a problem. FIG. 4 is an explanatory diagram showing an outline of the experimental apparatus, and Table 1 is a table showing the water quality of each water system and the amount of algae grown by the amount of chlorophyll a in the experimental apparatus of FIG.
The system I shown in FIG. 4 is a system in which river water is collected, sand and the like are removed by a sedimentation tank, and then the water is directly used as a sample. In a reaction vessel with a capacity of 5 liters, in which water is treated with carrier I for 30 minutes (biological reaction of microorganisms supported on a microorganism-supporting carrier including trace metal oxidation microorganisms) Similarly, system III is a system in which system I water is treated at a rate of 2.5 L / h in a reaction tank having a capacity of 5 L, that is, system I water is treated for 120 minutes. is there. Samples of these three systems were collected in several batches and taken back to the laboratory to measure the water quality of each system (total phosphorus, total nitrogen, soluble manganese concentration), and then occurred in the dam reservoir After a very small amount of algae was inoculated, the algae was cultured for 8 to 10 days, and the amount of the grown algae was measured by the concentration of chlorophyll a. Table 1 below shows the average of the measurement results (average of several times).

  As can be seen from Table 1 above, the I- to III-based waters are generally the same as the causes of eutrophication, but there is no difference in the concentration of phosphorus and nitrogen. Even in the case of culturing with, the concentration of chlorophyll a is clearly reduced as compared with the water of system I, and it is recognized that the growth of algae is suppressed. This is because there is no difference in the concentration of phosphorus and nitrogen, so the soluble manganese is oxidized and insolubilized by the action of the trace metal microorganisms supported on the microorganism-supporting carrier. It is thought that the intake of (manganese) was inhibited.

  As described above, the embodiment of the present invention has been described. However, the embodiment is merely an example, and the biological reaction tank, the aeration means, and the water surface moving means can be replaced with conventional techniques. Even in such a case, it is clear that the above-described effect is achieved. In addition, the shape, material, and the like of each configuration shown in the drawings are merely preferable examples, and can be arbitrarily changed and modified within the scope described in the claims in the implementation. . Algae is a general term for photosynthetic organisms (plants) that mainly live in water, and is used to include seaweeds and phytoplankton. This seaweed includes three groups with different colors, shapes, and lifestyles, such as green algae such as aonori, brown algae such as kombu and wakame, and red algae such as sea cucumber. It includes the kind.

BRIEF DESCRIPTION OF THE DRAWINGS It is a structure explanatory drawing which shows the general | schematic structure of the algal growth suppression apparatus which concerns on embodiment of this invention. 2 is a photograph of a microorganism holding carrier according to an embodiment of the present invention. It is explanatory drawing which shows the installation position of a water temperature climbing layer and an algae growth suppression apparatus. It is explanatory drawing which shows the outline | summary of the experimental apparatus of the effect confirmation experiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Algal growth suppression apparatus 2 Biological reaction tank 20 Reaction tank main body 21 Screen 22 Screen 3 Aeration means 30 Aeration plate 31 Pressure feed pipe (pneumatic feed means)
32 Compressor (pneumatic feed means)
4 trolley (water surface movement means)
40 Variable fixing rod (connecting means)
S Microbe holding carrier

Claims (4)

A method for suppressing the growth of algae in a closed water area such as a dam reservoir,
A biological reaction tank containing a microorganism holding carrier capable of supporting microorganisms is installed near the surface layer of the closed water area, having a screen capable of inflow or outflow of water at the upper part and the lower part, and the biological reaction tank is formed by aeration means. By aeration from below, a gentle upward flow is generated inside the biological reaction tank and a gentle downward flow is generated outside the biological reaction tank, and the microbial holding carrier is continuously fluidized to grow algae. A trace metal oxidation microorganism that oxidizes a trace metal necessary for spontaneously carrying on the surface of the microorganism-supporting carrier,
Oxidizing and insolubilizing the trace metal contained in the water of the closed water area introduced from the lower part of the biological reaction tank by the trace metal oxidation microorganisms supported on the microorganism holding carrier,
A method for inhibiting algal growth in a closed water area, characterized in that the trace metal oxide oxidized by the trace metal oxidation microorganism is settled in the downward flow. It is an apparatus used for the algal growth suppression method in the closed water area according to claim 1,
A biological reaction tank having a screen capable of inflow or outflow of water at the upper part and the lower part and containing a microorganism-supporting carrier capable of supporting microorganisms;
Aeration means connected to the lower part of the biological reaction tank at a predetermined interval and aerated by sending in air;
A water surface moving means having a connecting member for suspending the biological reaction tank to a predetermined depth, and capable of moving in the vicinity of the water surface of the closed water area;
An apparatus for inhibiting algal growth in a closed water area, comprising:   The algae growth-suppressing device in a closed water area according to claim 2, wherein the microorganism holding carrier is made of a resin having a specific gravity of about 1.   The length of the connecting member can be adjusted, and the installation depth of the biological reaction tank can be changed according to the depth of the water temperature climbing layer. The algal growth suppression apparatus in the closed water area as described in 2.