WO2005044741A1

WO2005044741A1 - Water treatment method and apparatus using fish

Info

Publication number: WO2005044741A1
Application number: PCT/JP2004/016742
Authority: WO
Inventors: Atsushi Kobayashi; Yuichi Fuchu; Kenji Sawai; Yasuko Shinjo; Sinya Soeda; Toshio Takeuchi
Original assignee: Ebara Corporation; The President Of Tokyo University Of Marine Science And Technology
Priority date: 2003-11-11
Filing date: 2004-11-11
Publication date: 2005-05-19
Also published as: JPWO2005044741A1

Abstract

It is intended to provide a water treatment method and an apparatus therefor wherein the generation of micrometazoans such as chironomid can be inhibited without using any insecticide in a septic tank into which sewage having been treated to a high extent flows. A treatment apparatus for eliminating micrometazoans generating in treated sewage in a septic tank into which the sewage having been treated to a high extent and sterilized flows, wherein fish preying on the micrometazoans in the treated water are fed in the septic tank at such a density as allowing continuous survival thereof, and the septic tank is provided with a lighting window and/or lighting facilities for subjecting the fish to light. It is favorable that the water treatment apparatus has a filtration unit for filtering the treated water flowing out from the septic tank.

Description

Specification

Water treatment method and apparatus using fish

Technical field

The present invention relates to water treatment using fish, and more particularly to a method for controlling micro metamorphic animals such as moss larvae and hills generated in treated water after highly treating sewage such as sewage and drainage. Law and equipment.

^ Scenic technology

[0002] In the treatment of sewage and wastewater, the power S that performs treatment mainly on biological treatment such as the activated sludge method and the aerobic filter method, and a small amount of treated water It contains solids mainly composed of microbial floc fragments used for the treatment of refuse. Since these solids settle at the site where the flow velocity is slow, they tend to accumulate at the bottom in a treated water tank or the like. The sediment at the bottom of the aquarium contains micro metazoans such as larvae and hills of the midge, and also feeds on them, so the growth of micro metazoans in treated aquariums, etc., especially in the spring from summer when the water temperature rises to summer. · Occurs.

[0003] Also, in the recent movement toward the formation of a recycling-based society, especially in metropolitan areas, sewage treated water is regarded as a water resource, and this is further treated with an aerobic filter method and ozone treatment. Advanced treatment by the law is used to effectively use water for flushing toilets, sprinkling water, or artificial landscapes such as artificial ponds, artificial babbles, and waterfalls. In the advanced treatment of sewage for the purpose of reusing treated water, the power of sterilization by ozone treatment and chlorination is used.At this time, specific organisms such as mosquito larvae that are resistant to these treatments are selectively selected. They survive and sometimes cause outbreaks under environmental conditions free of predators and competitors. In the reuse of sewage treatment water, if a large amount of squirrels or the like occurs in the distribution tank, which is a storage tank for the highly treated sewage, larvae of the suricate will be found in facilities where hotels and department stores use the highly treated sewage. There is a concern that it may be leaked, which is a problem.

[0004] At present, extermination by spraying insecticides is a general remedy for the mass outbreak of musurica and the like, and an effect has been obtained. However, the use of pesticides is not only costly, but also provides a temporary benefit to insecticides. There is a problem that it induces the appearance of slime, etc., and the insecticide used so far becomes ineffective. In addition, the act of adding an insecticide to the highly treated sewage water used for sprinkling water and scenic landscape water where the user does not intend to do so has the potential to adversely affect the environment. It is also in conflict with the future of sewerage business, which emphasizes the conservation of land. For these reasons, the application of insecticides cannot be said to be an appropriate method, and there is a demand for an alternative method for controlling micro metazoans such as suricas. `` The world of Ustrica '' p.

91-94 (published by Baifukan Co., Ltd. on January 30, 2001; see “Johkasou Kenkyu” Vol. 13, Nol. P. 3-12 (2001)).

Disclosure of the invention

Problems to be solved by the invention

[0005] In view of the above-mentioned problems of the prior art, the present invention seeks to suppress the occurrence and proliferation of micro metazoans such as larvae and leeches of musuricas by using fish as predators. . In other words, an object of the present invention is to produce large quantities of micro metazoan animals such as suricas without using pesticides by feeding fish to a treated water tank or the like that stores highly treated water in advanced sewage treatment facilities. It is an object of the present invention to provide a water treatment method and apparatus capable of suppressing water pollution.

Means for solving the problem

[0006] In order to solve the above problems, one embodiment of the present invention is characterized in that sewage is treated biologically to form treated water, and the treated water is stored in a treated water tank in which fish are released. Water treatment method is provided. Further, in another aspect of the present invention, a water treatment method for removing micrometamorphous animals generated in treated water in a treated water tank into which treated water in which sewage is highly treated, such as sewage high-grade treatment or high-grade treatment, flows. In the above-mentioned method, a water treatment method is provided, wherein fish are directly fed into the treated water tank at a density capable of continuously surviving and prey on and remove micrometamorphous animals in the treated water. . In the above-mentioned water treatment method, it is preferable to supply light required for predatory activity of fishes to micrometamorphous animals to a treatment tank for releasing fish.

[0007] Further, according to the present invention, in the water treatment device for removing micrometamorphous animals generated in the treated water in the treated water tank into which the treated water obtained by highly treating the wastewater flows, the treated water tank includes: That fish that prey on micro metazoans in the treated water are continuously released at a density that allows them to survive, and that lighting windows and / or lighting equipment for supplying light to the fish are provided. This is a characteristic water treatment device. In the water treatment device, a filtration device for filtering treated water flowing out of the treatment water tank can be provided.

The invention's effect

[0008] According to the present invention, in a system for highly treating sewage such as sewage and drainage, a fish is fed as a predator to a treated water tank or the like that stores highly treated water, and minute larvae such as mosquito larvae are used. Predation of metazoans can suppress the occurrence of a large number of micrometastasis that occurs in treated water tanks. As a result, it is possible to suppress the mass outbreak of micrometamorphous animals such as moss larvae and leeches, which has been a problem particularly in advanced treatment of sewage for the purpose of reusing treated water, without adding pesticides. It is now possible.

Brief Description of Drawings

FIG. 1 is a schematic configuration diagram showing one example of a water treatment apparatus of the present invention.

FIG. 2 is an explanatory diagram showing an outline of a water treatment system in which a treatment tank for releasing fish according to the present invention is combined with an advanced treatment system for sewage.

FIG. 3 is an explanatory view showing an outline of a water treatment system in which a treatment tank for releasing fish according to the present invention is combined with an advanced treatment system for sewage.

FIG. 4 is a schematic diagram showing the structure of a simulation tank used in Example 3.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, the water treatment method of the present invention will be described in detail. As the system for highly treating sewage such as sewage and wastewater of the present invention, various treatment systems for ordinary sewage facilities and food wastewater can be adopted. Nonetheless, equipment that poses a problem in the incorporation of small metazoans into treated water, such as advanced sewage treatment facilities for the purpose of reusing treated water, is particularly effective. That is, the present invention is applied to an advanced sewage treatment facility that intends to effectively use the treated water for flushing toilet water, sprinkling water, or landscape water for artificial ponds, artificial babbles, artificial waterfalls, and the like. Can apply power S. Examples of advanced sewage treatment include sedimentation treatment, biological treatment, activated sludge treatment, coagulation sedimentation treatment, biofilm filtration treatment, ozone treatment, and combinations thereof. S power In sewage and wastewater treatment systems, some solid matter (sludge) accumulates at the bottom of the treated water tank, and micrometamorphous animals such as mosquito larvae and leeches are likely to occur in this area. In particular, in a treated water tank after ozone treatment or chlorination, specific species of mosquito larvae and leeches that are resistant to these treatments selectively survive, causing large outbreaks. I'm sorry.

FIG. 1 shows the concept of a water treatment apparatus according to one embodiment of the present invention. The treated sewage water obtained by performing the various advanced treatments described above is introduced into a treated water tank where fish are released, and, depending on the case, is discharged after being filtered by a filter, or is called a so-called medium. It can be reused as water for washing, water for sprinkling, water for scenic landscape, various tap water, etc. in the form of waterways.

[0012] In the present invention, fish are directly fed to a treated water tank into which treated water is introduced, and prey on micrometamorphous animals such as larvae and hills with slime power to suppress their generation and proliferation. As fish to be used, omnivorous fish such as guppy, tilapia, koi, crucian carp, and loach are appropriate. Although not shown, it is desirable to add oxygen supply equipment, a pH adjustment mechanism, a temperature adjustment mechanism, and other equipment for maintaining an appropriate environment for fish to the treatment tank for releasing fish as necessary. Masire,

[0013] The supply of light to a treatment tank for releasing fish is an important factor not only in favor of foraging during predation of fish but also for maintaining a good ecological rhythm of fish. It is preferable to maintain the activity of fish by installing a window for lighting and / or installing a lighting system and running a timer to give a light rhythm similar to day and night in nature. Depending on the type of fish to be released, it is effective to use a special light source such as near infrared rays. In this way, the fish feed on microsurvivors such as mosquito larvae and leech by preparing the surviving environment of the fishes and releasing them, thereby generating micro metamorphic animals such as larvae of mossel and hills. Proliferation is deterred.

[0014] Depending on the type of fish used, the state of occurrence of micro metazoans such as larvae and leeches of the midge, or the properties of sludge mixed in the aquarium, the important thing here is that This is the amount of fish released based on the amount of micro metazoan animals such as squirrel larvae and leech, and the amount of organic sludge. In general, per day per kilogram of fish weight, The amount of micro metazoan such as hills and organic sludge is preferably 5 to 200 g, more preferably 20 to 70 g as dry weight. If the amount of small metazoans and organic sludge to be fed is less than 5 g as dry weight per day per 1 kg of fish body weight, the fish will starve and it will be difficult to survive continuously. On the other hand, if the amount of micro metazoans and organic sludge exceeds 200 g, fish will become saturated, leaving behind eating, and the effect of preventing micro metamorphosis on the micro metazoans will not be sufficiently obtained. In order to continuously obtain the effect of controlling outbreaks on micro metazoans, the relationship between the amount of micro metazoans such as mosquito larvae and organic sludge flowing into the treated water tank and the amount of fish to be released is determined by the fish weight. By adjusting the amount of micrometastasis and organic sludge per lkg to 5 g-200 g, preferably 20 g-70 g per day on a dry basis, fish can survive healthily and sufficiently. A predatory effect can be obtained, and the ability to stably obtain a long-term deterrent effect on small metazoans can be achieved.

[0015] The fish density in the aquarium to be released is also an important point, but this depends on the amount of bait (sludge etc.) supplied. It is possible to calculate the amount of fish to be released so that it falls within the above range.

[0016] Further, as shown in Fig. 1, the treated water in the treated water tank is guided to a filter, and the effluent from the water tank from which the fish have been released is included in the effluent from the turtle. By removing metazoans and the like, better processing can be realized.

[0017] Figs. 2 and 3 show the concept of a form in which the treatment tank for releasing fish according to the present invention is combined with an advanced sewage treatment system. In the embodiment shown in FIG. 2, sewage is treated by an advanced treatment system that performs sedimentation treatment, activated sludge treatment, biofilm filtration treatment, ozone treatment, and, in some cases, filtration treatment and chlorination treatment in this order. The resulting treated water generally has an SS power of 2 g / mL or less-6 mg / L, pH of 5.8.8.6, COD of 1 mg / L or less-8 mg / L, and BOD of 3 mg / L or less-6 mg. This is introduced into the treated water tank where the fish according to the present invention has been released, and then, if necessary, after being passed through a filter, discharged, or used for washing water, sprinkling water, and repair. Reuse as scenic water. In the embodiment shown in Fig. 3, sewage is treated by an advanced treatment system that performs sedimentation treatment, activated sludge treatment, coagulation sedimentation treatment, ozone treatment, filtration treatment, and, in some cases, chlorination treatment in this order. Do . The resulting treated water generally has an SS of 0.2g / mL or less-6mg, a pH of 5.8-8.6, a COD of lmg / L or less-8mg / L, and a BOD of 3mg / L or less-6mg. This is introduced into a treated water tank where fish that have been used in the present invention have been released, and then, if necessary, after passing through a filter, or discharged, or used for washing water, sprinkling water, scenic water, etc. To be reused as Example 1

[0018] In this example, a comparison was made between the case where fish were released in a water tank simulating a treated water tank, the case where light was blocked, and the case where fish were released in a tank simulating a treated water tank. did.

[0019] Two simulated water tanks with a water tank volume of 500L and an effective volume of 250L were prepared, one for natural light and the other for shading, with 250L of water in a tilapia (approximately 20mm long). Two were released. As for the water tank under natural light conditions, a water tank under the same condition without tilapia was prepared for comparison. Ozonized water from the secondary sewage was passed through these tanks at a flow rate of 500 L / day for 6 weeks. The occurrence of aurica in this aquarium was visually observed once a week. Table 1 shows the experimental results.

[0020] [Table 1] Table 1: Experimental results of Example 1 (number of suricas generated, unit: animals / test tank)

In the aquarium where no fish were released, a streak-like mass formed by the nesting activity of moss larvae was observed at the bottom one week after the start of water supply, and 5 weeks after the start of water supply The emergence of adults and the mass of eggs laid 6 weeks later were confirmed. Ma In addition, although the effect of suppressing fish outbreaks was observed in the aquarium where fish were released under light-shielded conditions compared to the aquarium where no fish were released, a small amount of polyurethane was placed on the bottom of the aquarium after the fourth week of the experiment. Streaky masses formed by larvae of the larvae of the larvae began to be seen. On the other hand, in the aquarium where tilapia was released under the condition of no shading, the occurrence of musurika was not visually observed. In this way, by feeding tilapia under light-supplied conditions, it was possible to suppress the occurrence and growth of thurica in the treated water tank. Example 2

[0021] In this example, a comparison was made between effluent when fish were fed into a tank simulating a treatment tank and sewage secondary treatment water subjected to ozone treatment for sewage water, with and without filtration. did.

[0022] Two tilapias (with a body length of about 20mm) were released in a simulated aquarium with a tank volume of 500L and an effective volume of 250L. In this tank, ozone-treated secondary sewage water was passed continuously at a flow rate of 500 L / day for 6 weeks. The effluent from this tank was filtered through a screen with a pore diameter of 25 βm on one side, and the other was not filtered, but received in a model receiving tank with a 500-liter tank capacity and a 250-liter effective volume, respectively, and the situation of the occurrence of suricas in this receiving tank Was visually measured once a week. In addition, a water tank under the same conditions where tilapia was not fertilized was prepared as a comparative object, and the same measurement was performed without filtration. Table 2 shows the experimental results.

[Table 2]

Table 2: Experimental results of Example 2 (number of squirrels generated, unit: animals test tank)

In the aquarium that did not release fish (tilapia), two weeks after the start of water flow, streak-shaped clumps formed by the nesting activity of moss larvae at the bottom began to be observed. After 5 weeks, the emergence power of the adult was observed. After 6 weeks, the egg mass laid was confirmed. When the effluent from the treated tank where the fish were released was not filtered, the number was smaller in the receiving tank that received the effluent than when the fish were not released. Some streak-like masses formed by the nesting activity of the mosquito larvae at the bottom began to be observed, and adult emergence of the adults was confirmed 6 weeks after the passage of water. On the other hand, when the effluent from the treated tank where the fish were released was filtered, the occurrence of musurica was not visually observed in the receiving tank that received the effluent filtered water. In this way, by releasing tilapia into the treated water tank and filtering the effluent from the treated water tank, it was possible to suppress the occurrence of musurica in the subsequent water receiving tank.

Example 3

[0024] In this example, the effect of feeding fish for one year to a large aquarium simulating a treated aquarium was examined for water obtained by treating ozone-treated secondary sewage (sewage advanced treated water). .

[0025] 100 tilapias (body length: about 20 mm) were bred in a simulated water tank having a water tank volume of 30 m ³ and an effective volume of 18 m ³ . To the water tank, the sewage secondary treatment water was treated with ozone water of 40m ³ / day flow rate For one year. Figure 4 shows the structure of the simulation tank used. The simulated aquarium has a structure that can be hermetically sealed by attaching a lid on top, and has two vents with a mesh of 0.2 mm mesh and one inspection port with a lid that can be opened and closed. In addition, a window for lighting made of a transparent acrylic plate is attached to a part of the upper lid, and a 200W mercury lamp and a 30W incandescent lamp are alternately turned on for 12 hours by timer control above this window. By changing the intensity of the light irradiating the inside of the aquarium, a cyclic change such as day and night was given.

[0026] Furthermore, a DO (dissolved oxygen) sensor and a water thermometer are attached to continuously monitor the DO and water temperature in the water tank, and an underwater camera is installed so that the inside of the treated water tank can be observed from outside. I made it. The treated water outlet is raised and installed facing the surface of the water to prevent water from overflowing and flowing out, thereby preventing the sediment in the water tank from being sucked into the outlet and flowing out. A drain drain was installed at the bottom of the tank. A mesh with a mesh width of 5 mm was attached to the treated water outlet and drainage drain to prevent fish from flowing out.

[0027] During the experimental period, the sediment at the bottom of the water tank was removed by inserting the upper inspection rocker hose and pumping it out once every two months.

[0028] As a result of this experiment, it was confirmed that during the experiment period, no adult mosquitoes were observed in the gas phase portion of the treated water tank, and that the generation and propagation of the moss in the simulated treated water tank were suppressed. Was. Also, at the end of the experiment, all 100 tilavias that were initially released have survived in the treated water tank, and it was found that the fish could survive throughout the year under conditions where no artificial food was supplied from outside. confirmed.

Claims

The scope of the claims

[1] A water treatment method comprising biologically treating sewage to form treated water, and storing the treated water in a treated water tank in which fish are released.

[2] A water treatment method for removing minute metazoans generated in the treated water in a treated water tank into which treated water having a high degree of treatment of sewage flows, wherein fish can be continuously alive in the treated water tank. A water treatment method comprising directly feeding at a density to prey and remove micrometamorphous animals in the treated water.

3. The water treatment method according to claim 1, wherein light required for predatory activity of the fish by the fish is supplied to the treatment tank for releasing the fish.

[4] In a water treatment apparatus for removing minute metazoans generated in treated water in a treated water tank into which treated water obtained by highly treating sewage flows, the treated water tank includes minute metazoans in the treated water. Characterized by the fact that fish that feed on the fish are maintained at a continuously viable density and are provided with lighting windows and / or lighting equipment to supply the fish with light.

[5] The water treatment device according to [4], further comprising a filtration device for filtering treated water flowing out of the treated water tank.