JP2015029968A - Method and apparatus for removing microorganism and organic matter in water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for separating and removing a harmful microorganism or the like contained in agricultural water and service water for a food product project by simple operation.SOLUTION: The method for removing a microorganism and an organic matter in water is provided in which a flotation machine (FM) is supplied with water to be treated (W1) containing a microorganism (including a virus, same hereinafter) or a microorganism and an organic matter (excluding a microorganism and a virus, same hereinafter) and at least a collector as an additive (C), and further supplied with microbubbles from a lower part of the flotation machine (FM), and floating substance (U) including the concentrated microorganism or the concentrated microorganism and organic matter are recovered from an upper part of the floatation machine (FM), while underflow water (W2) from which the microorganism or the microorganism and organic matter are removed is recovered from the flotation machine (FM).

Description

  The present invention relates to a method and apparatus for removing microorganisms such as algae, bacteria (bacteria), viruses, and organic substances in water to be treated.

Conventionally, there are many methods for sterilizing microorganisms such as algae in water and bacteria. Moreover, in recent years, commercialization of hydroponics that uses sunlight or artificial light to give and cultivate nutrients necessary for growing crops as liquid fertilizer (culture solution) dissolved in water has been actively carried out. However, if bacterial diseases such as bacterial wilt, scab, etc., filamentous fungal diseases, soil infectious viral diseases, etc., which are diseases caused by circulating use of the culture solution, must be sterilized and removed (" All of hydroponic cultivation-basic technology to support plant factories ", Sebundo Shinkosha, publisher: Yuichi Ogawa, issued July 31, 2012, pages 181 to 186).
However, although it is possible to disinfect and disinfect to some extent by chemical disinfection and disinfection methods such as bacteria in water, it is expensive and expensive to treat and dispose of treated water containing added chemicals. Will lead to up.

  Therefore, in reality, the use of chemical agents is unavoidable as much as possible for the sterilization and sterilization of agricultural water used for hydroponics and the like, and the sterilization and sterilization of water for food-based businesses. In addition, since there are no drugs that act directly against viruses, early detection is important for preventing viral diseases ("New development of solar plant factory", published by Yokendo, editor: Noguchi Nobu Et al., Issued April 20, 2012, pages 324-326). In addition, water purification methods based on membrane separation methods that do not use drugs such as ultrafiltration membranes (U / F membranes) have been proposed and researched and developed. In this case, submicron to several micrometers In order to filter microorganisms of a large size, backwashing of the membrane is frequently required, and the processing speed is reduced.Furthermore, the microorganisms are clogged due to soft particles and the frequency of membrane replacement is high, so that the operation can be maintained. There is a problem that a great deal of cost must be borne for management.

Patent Document 1 includes a microbubble sterilization apparatus that includes a bubble generator that supplies a water tank in which a sterilization target of human or animal skin is immersed, and generates microbubbles to sterilize in a liquid. It is disclosed.
In Patent Literature 2, a hydroponic cultivation tank in which an upper part is covered with a building and a hydroponic bed for cultivating a plant on the surface of the hydroponic liquid is suspended, and a micro-nano bubble is added to the introduced hydroponic liquid. A micro-nano bubble aquarium for containing water and an activated carbon tower for decomposing the organic matter and plant waste in the introduced hydroponic liquid by adhering to the activated carbon and propagating by microorganisms, A hydroponics apparatus capable of sterilization that is circulated in this order between the hydroponics tank, the micro-nano bubble tank, and the activated carbon tower is disclosed.
Since micro-nano bubbles have an sterilizing action because they have an oxidizing action, by introducing the hydroponic liquid from the culture tank into the micro-nano bubble aquarium where the micro-nano bubble generator is installed, It is described that pathogenic bacteria can be sterilized by micro-nano bubbles.

Patent Document 3 discloses a method for disinfecting and purifying shellfish, in which a hole is formed in a shell portion where the shellfish body is not in close contact, and aseptic salt water to which microbubbles containing ozone are forcibly sent is sent from this hole. Has been. It is described that norovirus can be inactivated by adding microbubbles of high-concentration oxygen containing ozone to sterile salt water.
In Patent Document 4, an aluminum electrode unit is provided in a treatment tank for collecting water used in a pre-rinsing process among water used in a commercial washing machine, and microbubbles are generated to aggregate impurities. , To promote precipitation.
Patent Document 5 introduces a microbubble generating nozzle into water containing a detergent stored in a washing tub, and generates microbubbles to generate fine cream-like bubbles (detergent bubbles). It is disclosed that the water (microbubble mixed water) containing detergent bubbles and microbubbles generated in this way is supplied into a washing tub through a water outlet and used for washing.

JP 2009-195440 A JP 2008-206448 A JP 2008-199946 A JP 2006-328762 A JP 2006-167185 A

In the sterilization with microbubbles in the liquid disclosed in Patent Document 1, the sterilization rate is not sufficient, and no means for removing bacteria from the liquid out of the system is mentioned. Disinfection of pathogenic bacteria in hydroponic liquid using micro-nano bubbles disclosed in Patent Document 2 is not sufficient for sterilization.
In the treatment of irrigation water, it is known that when microbubbles containing ozone are supplied, a sterilizing effect can be obtained. However, simply supplying microbubbles to the irrigation water provides a sufficient sterilizing effect in most cases. It is known that there is no such thing ("Latest Trends in Water Purification Technology", CMC Publishing, supervised by Masataka Sugawara, published June 30, 2011, page 140).
In the method of disinfecting and purifying shellfish in aseptic seawater using high-concentration oxygen microbubbles containing ozone disclosed in Patent Document 3, since ozone itself is harmful to plants, attention must be paid to concentration control and prevention of atmospheric diffusion. It is.
In the washing water recycling apparatus disclosed in Patent Document 4, it is disclosed that the generated microbubbles promote aggregation and precipitation of impurities, but no mention is made of a method for removing microorganisms. In the washing machine disclosed in Patent Document 5, it is disclosed that micro-bubbles are generated in detergent-containing water so that fine cream-like foam (detergent foam) is supplied into the washing tub and used for washing. Only.

  Therefore, development of a method for separating and removing harmful microorganisms and the like contained in water for use in agricultural water, food business water, etc. by a simple operation is required. However, it does not describe a method for separating and removing harmful microorganisms from these waters. The present invention solves the above problems and provides a method and apparatus for separating and removing harmful microorganisms and the like contained in water to be treated, such as agricultural water and food-based business water, with a simple operation. Objective.

As a result of intensive studies in view of the above circumstances, the present inventors added a small amount of additives to the separation / removal of harmful microorganisms and organic substances contained in water to be treated such as agricultural water and food business water. It has been found that by applying a foam flotation separation method (flotation method) that can be operated with (resource saving) and a small power source (energy saving), the microorganisms and organic substances can be separated and removed efficiently. It came to complete.
That is, the gist of the present invention is the invention described in the following (1) to (9).

(1) To-be-treated water (W1) containing microorganisms (including viruses; the same shall apply hereinafter) or microorganisms and organic substances (excluding microorganisms and viruses; the same shall apply hereinafter) and at least a collector as additive (C) Is supplied to the flotation machine (FM), and microbubbles are supplied from the lower part of the flotation machine (FM),
The microorganism or the floating substance (U) in which the microorganism and organic matter are concentrated is levitated and recovered from the upper part of the flotation machine (FM), and the microorganism, or the microorganism and organic matter are removed from the flotation machine (FM). Recovered underflow water (W2),
A method for removing microorganisms and organic substances in water (hereinafter sometimes referred to as a first embodiment).
(2) The method for removing microorganisms and organic substances in water according to (1) above, wherein the collection agent is a cationic surfactant or an anionic surfactant.
(3) The cationic surfactant is one or two or more selected from an amine salt type and a quaternary ammonium salt. A method for removing microorganisms and organic substances.
(4) The anionic surfactant is one or more selected from a carboxylate and a sulfate ester salt, and the microorganisms in water according to (2) above, How to remove organic matter.

(5) The additive (C) is a collection agent, and one or more selected from a foaming agent, a flocculant, and a pH adjuster. To (4), the method for removing microorganisms and organic substances in water.
(6) The average bubble diameter of the microbubbles supplied to the flotation machine (FM) is 100 μm or less, and the microorganisms and organic matter in water according to any one of (1) to (5), Removal method.
(7) The method for removing microorganisms and organic substances in water according to any one of (1) to (6) above, wherein the diameter or major axis of the microorganisms in the treated water (W1) is 10 μm or less.

(8) Consists of at least a flotation machine (FM), microbubble generation means provided in the lower part of the flotation machine (FM), floated substance collection means, and underflow water (W2) collection means In order to remove the microorganisms or the microorganisms and organic substances from the treated water (W1) containing microorganisms (including viruses; the same shall apply hereinafter) or microorganisms and organic substances (excluding microorganisms and viruses; the same shall apply hereinafter). Equipment,
Water to be treated (W1) and at least a collector as an additive (C) are supplied to a flotation machine (FM), and the microorganisms and organic matter are attached to and floated on the microbubbles generated from the microbubble generating means. Floating matter (U) recovery means for recovering the floated material (U) that has been placed is arranged in the upper part of the flotation machine (FM),
Underflow water (W2) recovery means in which the microorganisms, or the microorganisms and organic substances are removed from the water to be treated (W1) is arranged in a flotation machine (FM),
An apparatus for removing microorganisms and organic substances in water (hereinafter sometimes referred to as a second embodiment).
(9) The microbubble generating means is a microbubble generating means utilizing a pore method or a gas-liquid mixing / shearing method, wherein the microorganisms and organic matter in water according to (8) are characterized in that Removal device.

By adopting the “method for removing microorganisms and organic matter in water to be treated (W1)” of the present invention, water to be treated (W1) such as agricultural water and business water in which microorganisms such as algae, bacteria (bacteria) and viruses are present. By applying the microbubble flotation method to which at least a collector is added, the microorganism can be removed from the system, and the soluble / insoluble organic matter contained in the water to be treated (W1). Can also be removed.
Microorganisms are charged either positively or negatively in an aqueous solution, and at least a collection agent is added to the water to be treated (W1) containing such microorganisms, and the microorganisms are micronized by hydrophobizing the surface of the microorganisms. It becomes possible to perform floating separation by adhering to the bubble. The collection agent added to remove the microorganisms and organic substances present in the water to be treated (W1) is concentrated at the gas-liquid interface by utilizing the huge gas-liquid interface area generated by the introduction of microbubbles. And floating and separating with the microbubbles to enable discharge outside the system. The additive (C) used in the microbubble flotation method has a small addition amount, is inexpensive and has little persistence.
In addition, the adoption of the “underwater microbial and organic matter removal device” of the present invention allows the power source of the device itself to operate at least with an air compressor and a submersible pump for generating microbubbles. This is a revolutionary method for wastewater treatment systems.
The method for removing microorganisms in water or microorganisms and organic matter and the removal apparatus of the present invention can be applied to all water use fields in which water is used, and in particular, water to be treated (W1 in circulation use of agricultural water). It is effective for removing microorganisms and organic substances in

It is a figure which shows the relationship between the residual ratio (residual CFU) of the number of residual colony formation units (henceforth residual CFU) obtained in Example 1, and microbubble flotation time. It is a figure which shows the relationship between the ratio (residual TOC) of the residual total organic carbon in underflow water obtained in Example 1, and microbubble flotation time. It is a figure which shows the relationship between the residual CFU obtained in Example 2, and the microbubble flotation time in underflow water. It is a figure which shows the relationship between the residual TOC in underflow water obtained in Example 2, and microbubble flotation time. It is a figure which shows the relationship between the residual CFU obtained in Example 3, and the microbubble flotation time in underflow water. It is a figure which shows the relationship between the residual TOC in underflow water obtained in Example 3, and microbubble flotation time. It is a figure which shows the relationship between the residual CFU obtained in Example 4, and the microbubble flotation time in underflow water. It is a figure which shows the relationship between the residual TOC in underflow water obtained in Example 4, and microbubble flotation time. It is a figure which shows the relationship between the residual CFU in underflow water obtained in Example 5, and microbubble flotation time. It is a figure which shows the relationship between the residual CFU obtained in Example 6, and the microbubble flotation time in underflow water.

Hereinafter, [1] a method for removing microorganisms and organic matter in the treated water (W1) of the present invention (first embodiment), and [2] a device for removing microorganisms and organic matter in the treated water (W1) ( A second embodiment) will be described.
In the present specification, the unit “ppm” is a unit indicating the concentration on a mass basis.
[1] Method for removing microorganisms and organic substances in treated water (W1) (first embodiment)
The method for removing microorganisms and organic matter in the water to be treated (W1) of the present invention (first embodiment)
Flotation of treated water (W1) containing microorganisms (including viruses; the same shall apply hereinafter) or microorganisms and organic substances (excluding microorganisms and viruses; the same shall apply hereinafter) and at least a collector as additive (C) Supply to the machine (FM) and microbubbles from the lower part of the flotation machine (FM),
The microorganism or the floating substance (U) in which the microorganism and organic matter are concentrated is levitated and recovered from the upper part of the flotation machine (FM), and the microorganism, or the microorganism and organic matter are removed from the flotation machine (FM). The underflow water (W2) is recovered.

The method for removing microorganisms and organic matter in the water to be treated (W1) of the present invention before supplying the water to be treated (W1) and an additive (C) such as a collection agent to the flotation machine (FM). And can be prepared in advance.
The prepared water to be treated (W1) is supplied to the flotation machine (FM), microbubbles are supplied from the lower part of the flotation machine (FM), and microorganisms and from the upper part of the flotation machine (FM) are supplied. The floated material (U) in which the organic matter is concentrated is collected by means such as scraping, and the underflow water (W2) from which microorganisms and organic matter are removed is collected from the flotation machine (FM).
Below, (1) microorganisms and organic matter in treated water (W1), (2) additives, (3) microbubbles, (4) flotation machine (FM), (5) in treated water (W1) A method for removing microorganisms and organic substances by flotation will be described.

(1) Microbe and organic matter in treated water (W1) Hereinafter, treated water (W1) that is a target for removal of microorganisms or microorganisms and organic matter may be referred to as irrigation water.
(1-1) Microorganisms in water to be treated (W1) Microorganisms in water to be treated (W1) to be removed in the present invention include algae, bacteria (bacteria), viruses and the like. Although microorganisms are not strictly defined, they generally refer to microscopic organisms that cannot be clearly seen unless they are magnified with a microscope.However, microorganisms in the present invention include cells such as algae and protozoa, which are unicellular and multicellular organisms. In addition to organisms that exhibit little function or tissue differentiation, bacteria (bacteria) and viruses that cannot self-grow are included. Since the surface of the microorganism is often negatively charged, it is placed on the top of the flotation machine (FM) by a flotation means using microbubbles regardless of the type of the microorganism in the presence of a collection agent. It can be concentrated.
Most of the microorganisms have a diameter or a major axis of about 10 μm or less, and microbubbles are attached and float by the action of a collecting agent described later. In addition, when a plurality of these microorganisms gather to form a colony in the water to be treated (W1), a plurality of microbubbles adhere and float due to the action of the collection agent. .
Microorganisms have various shapes, but the diameter is spherical, and the major axis is the longest dimension that can be obtained in an elliptical shape, a rectangular parallelepiped shape, a thread shape, etc. in a straight line shape.
In addition, the to-be-processed water (W1) in this invention means the thing before carrying out a flotation process using a flotation machine (FM), and the thing to be treated (W1) what was pre-processed, such as mere filtration. )include.

(I) Algae is a general term for organisms that perform oxygen-generating photosynthesis, excluding moss plants, fern plants, and seed plants that inhabit the ground. Green algae and diatoms are commonly found in rivers. Although it exists, the diameter or major axis is usually about 10 to 50 μm.
(B) Bacteria
Bacteria (bacteria) are unicellular microorganisms with prokaryotic cells. They are a group of organisms that do not have a clear nucleus in their protoplasms. They mainly propagate through division and exist everywhere on the earth. Bacteria are also called bacteria and are unicellular organisms having a diameter or major axis of about 0.2 to 10 μm, larger than viruses, and having a hard cell wall. There are many types, but they are classified into cocci, bacilli and spirals according to their forms, and are roughly divided into gram-positive and gram-negative bacteria by gram staining (bacterial staining method). Bacteria are used for food processing and decomposition of organic matter, but many are pathogens. The bacteria to be removed in the present invention include bacteria such as bacterial wilt disease and scab disease, which are diseases caused by circulation in the above-mentioned hydroponics, and filamentous fungal diseases.

(C) Virus viruses are minute structures that can replicate themselves using cells of other organisms. They are smaller than the bacteria described above, and are composed of a protein shell and a nucleic acid contained therein. Because it does not have cells that are the smallest unit of life, it may be considered non-living. Its size ranges from several tens of nanometers for small ones to several hundred nanometers for large ones, which is about 100 to 1/1000 of the cells of other general organisms (several μm to several tens of μm). It is a size.

(1-2) The density | concentration of the organic substance in the organic substance water in to-be-processed water (W1) is displayed by total organic carbon (TOC).
Total organic carbon (TOC) is the organic substance carbon present in water expressed in mg / l. TOC consists of suspended organic carbon and soluble organic carbon. In general, rapid filtration, coagulation precipitation, and the like are known as methods for removing suspended organic carbon, and ozone oxidation, activated carbon adsorption, and the like are known as methods for removing soluble organic carbon.
In the removal of microorganisms or microorganisms and organic substances in the water to be treated (W1) of the present invention, additives (C) such as a collector and a foaming agent are total organic carbon (TOC) in the water to be treated (W1). Therefore, it is desirable that the amount of these additives (C) added be small although some organic substances are removed by flotation.

(2) Additive (C)
In the method for removing microorganisms or microorganisms and organic matter of the present invention, the collection agent is an essential component as the additive (C) added to the microorganisms, and the foaming agent, the flocculant, and the pH adjuster are treated water. (W1) A component that can be optionally added in order to indirectly improve the removal rate of microorganisms and organic substances in W1.

(2-1) Collection agent In the flotation machine (FM), for example, since the surface of microorganisms is usually negatively charged, it is difficult to adhere to the surface of negatively charged microbubbles. When the collector is added, the collector is attached to the surface of the microorganism and imparts hydrophobicity. As a result, the microorganism is easily attached to the surface of the microbubble and can float.
In the microbubble flotation of the present invention, the collecting agent used can be used without any limitation as long as it has the above-mentioned properties. It is desirable to select from ionic surfactants or anionic surfactants. The ionic surfactant used as a collecting agent used in the present invention is not only a cationic surfactant, but also an anionic surfactant acts to hydrophobize the surface of microorganisms and promote adhesion to microbubbles. To demonstrate. Examples of cationic surfactants and anionic surfactants (hereinafter, cationic surfactants and anionic surfactants may be collectively referred to as ionic surfactants) are illustrated below. The ionic surfactant used in the invention is not limited to the following examples.

(A) Cationic surfactants Those in which hydrophilic groups become positive ions are called cationic surfactants, and are classified into amine salt types, quaternary ammonium salts, pyridinium salts and the like.
Amine salt types are neutralized with hydrogen chloride (HCl), hydrogen bromide (HBr), organic acids, etc., and quaternary ammonium salt types and pyridinium salts exist as positive ions in a wide pH range. High water solubility. Cationic surfactants usually have strong interactions with living tissues and their components, and quaternary ammonium salt type benzalkonium chloride, benzethonium chloride, etc. have a bactericidal effect and are themselves biodegradable. high.

Amine salt types include primary amines (RNH ₂ · H ⁺ X ⁻ ), secondary amines (R, R′NH · H ⁺ X ⁻ ), and tertiary amines (R, R ′, R ″ N · H). ⁺ X ⁻ ).
As primary amine, octylamine hydrochloride, dodecylamine acetate, etc. As secondary amine, distearylamine, etc. As tertiary amine, N, N-dimethyldodecylamine acetate, dimethyllaurylamine hydrochloride, etc. These amine salt type surfactants preferably have about 6 to 15 carbon atoms.
Quaternary ammonium salt types include octyltrimethylammonium bromide, hexyldimethylbenzylammonium chloride (benzalkonium chloride) and the like.

(B) Anionic surfactants Anionic surfactants whose negative groups become negative ions are called anionic surfactants, and are classified into carboxylate salts, sulfate ester salts, sulfonate salts, phosphate ester salts, and the like.
Examples of the carboxylate include sodium laurate and sodium oleate, and the number of carbon atoms is preferably about 6-22.
Examples of the sulfate ester salt include sodium decyl sulfate and sodium dodecyl sulfate, and the number of carbon atoms is preferably about 6 to 20.

The concentration of the ionic surfactant added as a collection agent in the water to be treated (W1) is the kind of the ionic surfactant, the type of microorganisms and organic substances to be removed, and the water to be treated (W1). Although depending on the concentration in the medium, it can be added in a concentration range of 1 to 10,000 ppm in order to exert its function.
The addition of the ionic surfactant to the water to be treated (W1) may increase the concentration of organic substances in the water to be treated (W1), but the ions added by the microbubble flotation of the present invention. Since the ionic surfactant is concentrated in the suspended matter (U), the concentration of the ionic surfactant in the underflow water (W2) decreases. Although the ionic surfactant is highly biodegradable, it is desirable that the amount of the ionic surfactant added is small in order to reduce the total organic carbon concentration (TOC) in the water to be treated (W1). In consideration of such circumstances, the concentration of the ionic surfactant added as a collection agent in the water to be treated (W1) is more preferably 5 to 1,000 ppm, further preferably 5 to 500 ppm, and more preferably about 10 to 100 ppm. Particularly preferred.

(2-2) Foaming agent When the microbubbles are blown into the water to be treated (W1) depending on the type of ionic surfactant or the like added as a collecting agent to the water to be treated (W1), the foaming property is not sufficient. In some cases, a foaming agent can be added to a concentration of 1 to 10,000 ppm in the water to be treated (W1) in order to appropriately increase the foaming property.
Preferred examples of the foaming agent include nonionic surfactants (nonionic surfactants). A nonionic surfactant is a surfactant having a hydrophilic group that does not ionize when dissolved in water. Typical examples thereof include ester types such as glycerin fatty acid esters and ether types such as fatty alcohol ethoxylates. Can be mentioned. As the lower alcohol-based and lower ketone-based nonionic surfactants, nonionic surfactants having 6 to 8 carbon atoms are preferable.
Typical nonionic surfactant is a kind of polyoxyethylene alkylphenyl ether, including compounds such as polyethylene glycol p- (1,1,3,3-tetramethylbutyl) -phenyl ether. : Triton X-100 (Triton X-100).

(2-3) Flocculant In the method for removing microorganisms and organic matter in the water to be treated (W1) of the present invention, a flocculant can be added to the water to be treated (W1).
The flocculant is usually added to promote precipitation of activated sludge generated by decomposition of organic matter when treating industrial wastewater or the like with activated sludge. In the present invention, the flocculant is inorganic in the treated water (W1). A flocculant such as aluminum chloride or polyaluminum chloride as a flocculant can be added.
In the present invention, as an effect of adding the flocculant, no action has been found to reduce the number of remaining colony forming units (CFU), but the residual total organic carbon concentration (TOC) is reduced by the treated water (W1) system. In some cases, the effect is exerted. Examples of the inorganic flocculant to be added include aluminum chloride, polyaluminum chloride (PAC), and aluminum sulfate (sulfate band). The flocculant can be added in the range of 1 to 10,000 ppm in the water to be treated (W1).

(2-4) pH adjuster Since microorganisms in the water to be treated (W1) are assumed to have a surface having a substantially constant potential within a pH range of 2 to 12, add a pH adjuster. PH adjustment can be performed. The pH adjuster that can be used is not particularly limited, and in consideration of economy, sulfuric acid, hydrochloric acid, quicklime, slaked lime, caustic potash, caustic soda and the like can be used.

(3) Microbubbles In the method for removing microorganisms and organic matter in the water to be treated (W1) of the present invention, microbubbles are supplied to the lower part of the flotation machine, and the microorganisms to be removed in the presence of the collection agent Organic matter is levitated and collected. The average bubble diameter of the microbubbles is preferably 100 μm or less, more preferably 10 to 50 μm. When the average bubble diameter is in the above range, the removal rate of the microorganisms in the water to be treated (W1) can be improved from the viewpoint of slowing the bubble disappearance rate and the rising speed and the size of the microorganisms. it can. The microbubbles supplied from the lower part of the flotation machine (FM) are preferably air from the viewpoint of economy. For example, as described in the following non-patent documents a) to b), the low-concentration type bubbles have a distribution peak in the vicinity of a bubble diameter of 30 μm, and the bubble concentration is about several hundreds per milliliter (mL). The appearance is a little cloudy. In the present invention, the bubble concentration is preferably 1 / ml to 1 billion / ml, more preferably 100 / ml to 100,000 / ml.

Ordinary bubbles whose bubble size is larger than the microbubble size have a relatively high rising rate in an aqueous solution, and eventually burst at the liquid level. However, since the microbubble has a fine bubble volume, the ascending speed is slow and the microbubble continues to stay in water for a long time. The rising speed of microbubbles is known to follow Stokes' law, which is a formula that characterizes the motion of hard spheres in water, based on actual measurements in distilled water without internal convection (the following non-patent document). a-b).
Non-Patent Document a): “Effect of shrinking microbubble on gashydrate formation.” Takahashi, M. et al. J. Phys. Chem. B 107, 2003, p2171-2173
Non-Patent Document b): “ζ potential of microbubbles in aqueous solutions: electrical properties of the gas-water interface.” Takahashi, MJ Phys. Chem. B 109, 2005, p21858-21864
In addition, the measurement of the bubble diameter of the microbubble is performed by irradiating the microbubble in the aqueous solution with a blue-violet semiconductor laser light source and using a high sensitivity light receiving element (for example, Shimadzu Corporation, model: ALD-7500nano ). The bubble concentration of microbubbles can be measured by a conventionally known method.

Microbubbles have a colloidal side and are usually negatively charged. For this reason, the microbubbles repel each other, and the microbubbles are difficult to combine with each other, and the bubble concentration is not decreased. In addition, since the rising speed of the microbubbles is slow and the surface area is large, it becomes easy to attach the collection agent or the like to the surface.
On the other hand, normal bubbles having a bubble diameter larger than that of microbubbles are usually not charged, so that the bubbles are combined and gradually become larger.
Known microbubble generation methods include (a) pore method, (b) gas-liquid mixing / shearing method, (c) pressurized dissolution method, etc. ("All about microbubbles", Hirofumi Taisei, Japan Sangyo Publisher, published October 20, 2006, pages 144-149).

(A) Pore method The pore method is a method of generating microbubbles by a ceramic material or the like having through-pores at the nanomicron level. As an apparatus used for this system, an apparatus using a ceramic material having nano-micron level penetrating pores can be mentioned. For example, by allowing compressed air to pass through a SPG (Shirasu Porous Glass) membrane, microbubbles having an average bubble diameter of 30 to 50 μm can be easily generated, which is suitable for flotation in the present invention. In this case, an average pore diameter of about 0.1 to 6 μm can be used.
(B) Gas-liquid mixing / shearing method The gas-liquid mixing / shearing method is a method of generating bubbles by mixing and shearing a gas-liquid two-phase fluid such as water and air. It is a commonly used technique for generating microbubbles, which creates a vortex by causing a water flow, entrains gas (large bubbles) in the vortex, and breaks the bubbles apart when the vortex is collapsed The phenomenon is used. In the case of the two-phase flow swirling method, the generated microbubbles are often in a low concentration. As the bubble distribution, a single peak having a central particle diameter is observed around 30 μm. Note that a method of creating a pressurizing condition at the nozzle portion can generate high-density microbubbles.

(C) Pressure dissolution method The pressure dissolution method is a method in which a gas is efficiently dissolved in a pressurized liquid in a supersaturated state, and then released under reduced pressure to generate microbubbles.
The amount of dissolved gases such as oxygen and nitrogen in water increases in proportion to the pressure. The pressure-dissolving type microbubble generation method uses this characteristic. After a sufficient amount of gas is dissolved in water at a certain high pressure, the pressure is released and the supersaturation condition of the dissolved gas is reduced. produce. As a result, the excessively dissolved gas becomes unstable and the supersaturated gas molecules try to jump out of the water. As a result, a large amount of bubbles are generated in the water. If the timing is correct, it becomes a microbubble.
(D) Other methods for generating microbubbles include other ultrasonic methods, ultra-high speed turning methods, and the like.
By using the flotation means of the present invention, the microbubbles disappear on the liquid surface, so that solid-liquid separation for removing moisture from the floated material can be easily performed.

(4) Flotation machine (FM)
The flotation machine (FM) used in the method for removing microorganisms and organic matter in the water to be treated (W1) of the present invention is a microorganism in the water to be treated (W1) or a microorganism and organic matter in the water to be treated (W1). Water to be treated (W1) and at least a collector as an additive (C) are supplied to the flotation machine (FM), and microbubbles are supplied from the lower part of the flotation machine (FM), while Floating matter (U) enriched with microorganisms and organic matter is levitated and recovered from the upper part of the selector (FM), and underflow water (W2) from which microorganisms and organic matter are removed is recovered from the flotation device (FM). For example, a structure having substantially the same structure as a flotation machine that can be used for decontamination of contaminated soil shown in FIG. 2 of JP2013-64690A can be used.
The additive (C) such as a collecting agent can be mixed with the water to be treated (W1) in the flotation machine (FM), or the additive (C) is previously coated with a preparation tank, a line mixer or the like. What was added and mixed in treated water (W1) can be supplied to a flotation machine (FM).

  To the flotation machine (FM), water to be treated (W1) is continuously supplied to the trunk or upper part, and microbubbles are supplied from the lower part. Since the microbubbles supplied to the lower part of the flotation machine (FM) preferably rise in a state of being uniformly dispersed in the horizontal direction, the external shape of the flotation machine (FM) is cylindrical or polygonal. A cylindrical shape is preferable. It is desirable to supply the microbubbles in the flotation machine so as not to be unevenly distributed in the horizontal direction.

In addition, the height (L) from the microbubble supply position to the liquid surface of the flotation machine (FM) and the ratio (L / D) of the height (L) to the inner diameter (D) of the cylindrical portion are particularly limited. However, any structure that can secure the flotation time in the flotation machine (FM), which will be described later, may be used.
The horizontal section of the flotation part of the flotation machine (FM) is preferably a circle or regular polygon in order to avoid uneven distribution of microbubbles in the horizontal direction, and when the inner diameter (D) is large. Is
A partition plate whose interior is divided into a regular hexagonal shape or a regular quadrangular prism shape may be provided.
The supply position of the water to be treated (W1) to the flotation machine (FM) is the concentration of microorganisms and organic matter in the water to be treated (W1), the liquid level of the flotation machine, the amount of microbubbles supplied, etc. Although it depends, although it can be set as the trunk | drum or upper part of a flotation machine (FM), between the middle part and the upper part of the liquid level of a flotation machine (FM) trunk | drum is more preferable.
In the upper part of the flotation machine (FM), a receiver for collecting the floated material can be provided.

(5) Removal method by flotation of microorganisms and organic matter in treated water (W1) As described above, treated water (W1) containing microorganisms (or microorganisms and organic matter) and at least a collector as additive (C) Or water to be treated (W1) containing microorganisms (or microorganisms and organic matter) to which at least a collector is added as an additive (C) is supplied to a flotation machine (FM), and a flotation machine (FM ) To supply microbubbles from below
Underflow water (W2) from which the microorganisms or organic matter was removed from the flotation machine (FM) by levitating and collecting the floating substance (U) in which microorganisms or microorganisms and organic substances were concentrated from the upper part of the flotation machine (FM) Recover. By using at least a collector as the additive (C), the surface of the microorganism to be removed becomes hydrophobic, and the organic matter is also hydrophobic, so that it adheres to the microbubble surface and is treated with water ( W1) is levitated and separated.
For example, in the case where the removal method by flotation of microorganisms and organic matter in the water to be treated (W1) is performed by a batch method (batch method), etc.
A step of supplying microorganisms or water to be treated (W1) containing the microorganisms and organic matter and at least a collector as an additive (C) to a flotation machine (FM);
Supplying microbubbles into the water to be treated (W1) from the lower part of the flotation machine (FM);
A step of levitating and collecting the levitated matter (U) in which the microorganisms and organic matter are concentrated from the upper part of the flotation machine (FM);
Collecting the underflow water (W2) from which the microorganisms and organic matter have been removed from a flotation machine (FM),
The removal method of the microorganisms and organic substance in to-be-processed water (W1) is employable.

The floated material (U) that is floated and collected in the flotation machine (FM) by flotation is electrically charged with the charge on the microbubble surface and the charge on the microorganism surface by an ionic surfactant or the like as a collection agent. When summed, aggregates having a relatively low water concentration are formed by van der Waals force, and can be easily recovered by operations such as scraping.
In this way, the solid matter obtained by dehydrating the floating matter (U) obtained by floating the microorganisms and organic matter contained in the water to be treated (W1) is easy to handle.
By adopting the method for removing microorganisms and organic substances in the water to be treated (W1) of the present invention, the concentration of microorganisms contained in the water to be treated (W1) can be extremely reduced, and further the water to be treated (W1). The organic matter contained therein can also be removed as levitated matter (U).

[2] Device for removing microorganisms and organic matter in treated water (W1) (second embodiment)
The removal apparatus (2nd Embodiment) of the microorganisms and organic substance in the to-be-processed water (W1) of this invention is as follows.
At least, it was composed of a flotation machine (FM), microbubble generation means provided in the lower part of the flotation machine (FM), floated substance recovery means, and underflow water (W2) recovery means, An apparatus for removing the microorganisms or the microorganisms and organic matter from the treated water (W1) containing microorganisms (including viruses; the same shall apply hereinafter) or microorganisms and organic substances (excluding microorganisms and viruses; the same shall apply hereinafter). There,
Water to be treated (W1) and at least a collector as an additive (C) are supplied to a flotation machine (FM), and the microorganisms and organic matter are attached to and floated on the microbubbles generated from the microbubble generating means. Floating matter (U) recovery means for recovering the floated material (U) that has been placed is arranged in the upper part of the flotation machine (FM),
The underflow water (W2) recovery means in which the microorganisms or the microorganisms and organic substances are removed from the water to be treated (W1) is arranged in the flotation machine (FM).

(1) Flotation machine (FM)
The flotation machine (FM) in the second embodiment is the same as the flotation machine (FM) described in the first embodiment. In addition, although additive (C), such as a collection agent, can be mixed with to-be-processed water (W1) within a flotation machine (FM), this additive (C by a line mixer or a preparatory tank beforehand) ) Can be added to the water to be treated (W1) and mixed to be supplied to the flotation machine (FM).

(2) Microbubble generating means The microbubble generating means in the second embodiment is the same as the microbubble generating means described in the first embodiment. As microbubble generating means, a pore method, a gas-liquid mixing / shearing method, a pressure dissolution method, other ultrasonic methods, an ultra-high speed swirling method, etc. are known, but practically, an average bubble diameter is 100 μm. From the viewpoint of easily generating the following microbubbles stably and at a high concentration, it is preferable to use a pore method or a gas-liquid mixing / shearing method.

(3) Since the surface of the microorganism to be removed becomes hydrophobic by using at least a collector as the floating material recovery means additive (C), and the organic matter is also hydrophobic, the surface of the microbubbles It is possible to float and separate from the water to be treated (W1) relatively easily.
A receiver for collecting the floated material can be provided on the top of the flotation machine (FM).
After the floated material is collected from the flotation device by the receiver or the like, a dehydration filter can be arranged to remove the water in the suspended matter. A filter press can be used as a dehydrating filter. Such an operation not only prevents the trouble of clogging of the filter when using the filtering means and facilitates continuous operation, but also makes it possible to reliably separate the floating substance (U) as a solid. The type of the dehydrating filter is not particularly limited, and an oliver filter, a filter press, a filter using a bag made of a cloth material, or the like can be used.

(4) Underflow water (W2) recovery means The underflow water (W2) recovery means from which the microorganisms and organic substances have been removed from the treated water (W1) may be disposed below the flotation machine (FM). desirable. In addition, when the flotation machine (FM) is continuously operated, a portion below the microbubble supply port is preferable so that microbubbles are not entrained in the discharged liquid, and underflow water is supplied from the bottom of the flotation machine (FM). It is more preferable to collect as (W2).
When continuously operated, the underflow water (W2) is discharged in proportion to the supply amount of the water to be treated (W1) to the flotation machine (FM) per unit time. In this case, in order to keep the liquid level of the flotation machine (FM) constant, the underflow water (W2) can be extracted using a siphon phenomenon.

The present invention will be specifically described below with reference to examples. In addition, this invention is not limited to a following example. Samples, additives, flotation machines, analytical instruments, etc. used in the examples are described below.
(1) Sample (i) Microorganism to be removed (i) Commercial yogurt (Meiji Seika Co., Ltd., yogurt containing LG21 lactic acid bacteria (trade name: Meiji Probio Yogurt LG21 (registered trademark))
As a sample for simulated treated water, prepared is water prepared by diluting 3 mL of the above-mentioned commercially available Meiji Probio Yogurt LG21 in 1 L of distilled water, and then mixing the later-described additive in an aqueous solution (water sample 1) dispersed using a homogenizer. We used for flotation.
In addition, it confirmed by the CFU measuring method mentioned later that the cell number density | concentration in the simulated microbial cell prepared in this way is 4 * 10 < ^-5 > CFU / mL.
Moreover, in the following experiment, the density | concentration of this microbial cell number was made into 100%, and it was based on the removal rate.
(Ii) Bacteria attached to E. coli hands on the human skin surface are collected, cultured in a solution of glucose 5 g / L at a predetermined temperature (36 ° C.) for a predetermined time (50 hours), and used for flotation as water to be treated. did. The cell number concentration measured in the same manner as described above was 9.7 × 10 ⁻⁵ CFU / mL.
(Iii) Miscellaneous bacteria living in the drainage groove The bacteria collected from the household sink drainage groove were cultured in a 0.5 g / L glucose solution at a predetermined temperature for a predetermined time and subjected to flotation as treated water. The cell number concentration measured in the same manner as described above is 7.9 × 10 ⁻⁵ CFU / mL.

(B) Collection agent (i) Cationic surfactant N, N-dimethyldodecylamine acetate (N, N-DAA)
Benzalkonium chloride (BKC)
Dodecylamine acetate (DAA)
(Ii) Anionic surfactant sodium oleate (NaOl)
Sodium dodecyl sulfate (SDS)
(C) Polyoxyethylene alkylphenyl ether (trade name: Triton X-100 (hereinafter sometimes referred to as Tri)), which is a foaming agent nonionic surfactant.
(D) Flocculant aluminum chloride, polyaluminum chloride (PAC)

(2) Column-type microbubble flotation tester A column-type microbubble flotation tester (hereinafter referred to as a flotation tester) having a microbubble generator at the bottom to remove microorganisms and organic substances from the treated water. used.
(A) The flotation partial column part is a cylindrical flotation cell having an inner diameter of 50 mm and a height of 500 mm.
The flotation time was controlled by the time during which microbubbles were introduced using a batch system.
(B) Microbubble generator Using a small compressor, compressed air is supplied to an SPG membrane having through pores (average pore diameter of about 0.8 μm), which is a microbubble generator, in the water to be treated. Microbubbles were generated.
The microbubble generator has a cylindrical shape, and the upper lid part is formed with a seal structure. The copper part is an SPG (Shirasu Porous Glass) film (size: long) manufactured by SPG Techno Co., Ltd. And a connecting portion for introducing compressed air from the small compressor is provided in a cylindrical lower hollow portion.
The lid portion is provided at a position of about 5 cm from the bottom of the cylindrical flotation cell.
By introducing compressed air of 3.2 to 3.5 Kg / cm ² into the SPG membrane, microbubbles (bubble diameter of 50 μm or less) were generated in the water to be treated.
At the top of the flotation machine, a receiver was provided to collect the floating objects.

(3) Analytical equipment used (a) Number of colony forming units (CFU (Colony Forming Units per mililiter))
ATP concentration was measured by a plate method using a cleanliness measuring instrument (trade name: Lumistar C-110) manufactured by Kikkoman Biochemifa Co., Ltd., and the ATP concentration was converted to residual CFU in the water.
(B) Total organic carbon concentration (TOC)
The total organic carbon concentration (TOC) in the water to be treated was measured using a total organic carbon concentration measuring device (model: TOC-V) manufactured by Shimadzu Corporation.

[Example 1]
(1) Preparation of water sample to be treated In the above-mentioned water sample 1, the following three kinds of cationic surfactants as collection agents were each 100 (ppm), and neutral ionic surfactants (Triton X) as foaming agents. -100) was added to each so as to have a concentration of 100 (ppm), and the following water samples 1-1 to 3 were prepared as water to be treated.
Water 1-1: N, N-dimethyldodecylamine acetate (N, N-DAA) was used as a collector.
Water 1-2: Benzalkonium chloride (BKC) was used as a collector.
Water 1-3: Dodecylamine acetate (DAA) was used as a collector.

(2) Flotation method Supplying water 1-1 to 1-3 from the upper part of the flotation tester, and generating microbubbles of air from the microbubble generator installed at the lower part of the flotation tester, From the upper part of the flotation tester, the floated material in which microorganisms and organic substances were concentrated was collected in the receiver, and the underflow water from which the microorganisms and organic substances were removed was collected from the flotation machine.
The microbubble flotation (hereinafter also referred to as MBF) time for each water was increased by 10 minutes and adjusted to 60 minutes.

(3) Evaluation method and evaluation results The number of remaining colony forming units in the water during each microbubble flotation time obtained using the above water 1-1 to 3 (hereinafter, the number of colony forming units is referred to as CFU). And the residual total organic carbon concentration (hereinafter sometimes referred to as “residual TOC”).
Residual CFU ratio (%) (described as “residual CFU (%) in water” in FIG. 1; the same applies hereinafter) and microbubble flotation (MBF) time are shown in FIG. FIG. 2 shows the relationship between (%) (in FIG. 2, described as “residual TOC (%) in water”, the same applies hereinafter)) and MBF time.

As shown in FIG. 1, in the water 1-1 to which N, N-DAA was added, the residual CFU was about 0.5% 60 minutes after the start of MBF, that is, 99.5% of viable bacteria were removed. I understand that.
The removal indicated by the residual CFU includes inactivation of live bacteria and killing of live bacteria in addition to removal of live bacteria, inactivated bacteria, and dead bacteria to the outside of the system (hereinafter referred to as “killed bacteria”). ,the same).
The use of BKC and DAA water solutions 1-2 and 3 in 100 ppm concentration as the collection agent makes the removal of viable bacteria more remarkable, and the residual CFU is 0 in the water 1-2 after 60 minutes from the start of MBF. Since the residual CFU is about 0.1% with .2% or less and irrigation water 1-3, it can be seen that 99.8 to 99.9% of viable bacteria have been removed.
This is because inactivation of viable bacteria and discharge of viable bacteria out of the system occurred simultaneously by the action of the collector. Moreover, since the surface of bacteria is generally negatively charged on average, it is considered that the collector made of a cationic surfactant acted quickly and effectively.
As shown in FIG. 2, it can be seen that the organic matter of the irrigation water can be removed with the residual TOC of about 63% and the residual TOC of about 72% with the water 1-1 after 60 minutes of MBF with the water 1-2. In 1-3, the residual TOC is 170% before the start of MBF (the residual TOC is increased from 100% to 170% due to the addition of the additive before the start of flotation). The residual TOC was the same as that before the addition of additive No. 3.

[Example 2]
(1) Preparation of water sample to be treated The above-mentioned water sample 1 contains 100 (ppm) of the following two types of anionic surfactants as the collection agent and neutral ionic surfactant (Triton X as the foaming agent). -100) was added to each so as to have a concentration of 100 (ppm), and the following water samples 2-1 to 2 were prepared as water to be treated.
Water 2-1: Sodium oleate (NaOl) was used as a collector.
Water 2-2: Sodium dodecyl sulfonate (SDS) was used as a collector.

(2) Flotation method As described in Example 1, while supplying the water 2-1 to 2 from the upper part of the flotation tester, the microbubble generator installed at the lower part of the flotation tester Then, microbubbles of air were generated, and the floated material in which microorganisms and organic substances were concentrated was levitated and recovered from the upper part of the flotation test machine, and underflow water from which the microorganisms and organic substances were removed was recovered from the flotation machine.
The microbubble flotation time (MBF) of each water was increased by 10 minutes and adjusted to reach 60 minutes. In Example 2, the residual CFU and residual TOC of the underflow water after 5 minutes of MBF were measured for the water 2-1.
The control of the flotation time was performed in the same manner as described in Example 1.

(3) Evaluation method and evaluation results The relationship between residual CFU and MBF in water 2-1 and water 2 and 2 when NaOl and SDS are each added to a concentration of 100 ppm as an anionic collector is shown. 3 and the relationship between residual TOC and MBF is shown in FIG.
As shown in FIG. 3, in the water 2-1 to which NaOl was added, it can be seen that after 60 minutes from the start of MBF, the residual CFU was around 10% and 90% was removed. On the other hand, in the water 2-2 to which SDS was added, the removal effect became more remarkable, and it was found that residual CFU was removed 0.04% or less, that is, 99.96% or more of viable bacteria were removed 60 minutes after the start of MBF. .
This is presumably because the association was promoted by the presence of an amino group (—NH ₂ ) present on the water or on the surface of the fungus and dissociating into positive ions. The residual TOC in the water increased to about 153% due to the addition of the additive, but after 60 minutes of MBF, the residual TOC was around 90% in the NaOl addition system, and the residual TOC was around 60% in the SDS addition system. It can also be seen that it has been removed.

[Example 3]
(1) Preparation of water sample to be treated Benzalkonium chloride (BKC), which is a cationic surfactant, is added to the water sample 1 as a collection agent so as to have the following concentrations, respectively. And BKC and a foaming agent were added so as to have the following concentrations to prepare water for use 3-5.
Water for use 3-1: Water for use with benzalkonium chloride (BKC) concentration of 10 ppm 3-2: Water for use with benzalkonium chloride (BKC) concentration of 25 ppm 3-3: Water for use with benzalkonium chloride (BKC) concentration of 50 ppm Water for use in water 3-4: Water for use in benzalkonium chloride (BKC) concentration of 100 ppm 3-5: Water for use in benzalkonium chloride (BKC) concentration of 100 ppm, and neutral ionic surfactant (Triton X- 100) Water with a concentration of 100 ppm

(2) Flotation method As described in Example 1, while supplying water 3-1 to 5 from the top of the flotation tester, and from the microbubble generator installed at the bottom of the flotation tester Then, microbubbles of air were generated, and the floated material in which microorganisms and organic substances were concentrated was levitated and recovered from the upper part of the flotation test machine, and underflow water from which the microorganisms and organic substances were removed was recovered from the flotation machine.
The microbubble flotation time (MBF) for each irrigation water was adjusted to 5 minutes, and then MBF was increased by 10 minutes to 60 minutes.
The control of the flotation time was performed in the same manner as described in Example 1.

(3) Evaluation method and evaluation results In Example 3, the effect was confirmed as a collection agent, and BKC, a cationic surfactant, was used, and the additive concentration in the water to be treated was varied in various ways. FIG. 5 shows the relationship between the residual CFU and MBF, and FIG. 6 shows the relationship between the residual TOC and MBF.
In addition, although the BKC density | concentration in to-be-processed water was examined in the density | concentration range of 10-100 ppm, the addition of a foaming agent (Tri) is only when the BKC density | concentration in the water 3-5 for comparison is 100 ppm. As shown in FIG. 5, when the concentration of the collection agent BKC in the irrigation water increases, the residual CFU quickly decreases, and at BKC 50 ppm, the residual CFU is 0.1% or less after 60 minutes, that is, 99.9% or more of viable bacteria are removed. You can see that
On the other hand, when the concentration of BKC in the irrigation water was further increased to more than 50 ppm, the removal rate of viable bacteria slightly decreased to about 99.8 to 99.9%. Therefore, the optimum concentration range for the BKC concentration in the irrigation water Seems to exist.
In addition, when the BKC concentration in the irrigation water was 100 ppm, the Tri addition system (use water 3-5) and the Tri non-addition system (use water 3-4) were compared, and there was almost no difference in the residual CFU curve between them. However, as shown in FIG. 6, there is a speed difference in the residual TOC removal curve.

[Example 4]
In Example 4, an anionic surfactant SDS was used as a collection agent, and the influence on residual CFU and residual TOC when a flocculant was added to the water to be treated was examined.
In the same manner as in Example 2, water for use in which a foaming agent was added to the anionic surfactant SDS was also prepared.

(1) Preparation of water sample to be treated An anionic surfactant SDS as a collecting agent, a neutral ionic surfactant (Tri) as a foaming agent, and aluminum chloride and PAC as a flocculant in the water sample 1 described above. The following water samples 4-1 to 4 were prepared as water to be treated by adding them to the following concentrations.
Water for use 4-1: Anionic surfactant (SDS) concentration of 100 ppm and water for use with a foaming agent (Tri) concentration of 100 ppm 4-2: Anionic surfactant (SDS) concentration of 100 ppm, foaming agent (Tri ) Water for use with concentration of 100 ppm and flocculant (aluminum chloride) 50 ppm 4-3: Water for use with anionic surfactant (SDS) concentration of 100 ppm, foaming agent (Tri) concentration of 100 ppm, and flocculant (aluminum chloride) of 100 ppm Water 4-4: Water for flocculant (PAC) concentration of 100 ppm

(2) Flotation method As described in Example 1, while supplying water 4-1 to 4 respectively from the top of the flotation tester, and from the microbubble generator installed at the bottom of the flotation tester Then, microbubbles of air were generated, and the floated material in which microorganisms and organic substances were concentrated was levitated and recovered from the upper part of the flotation tester, and underflow water from which the microorganisms and organic substances were removed was recovered from the lower part of the flotation machine.
The microbubble flotation time (MBF) of each water was increased by 10 minutes and adjusted to reach 60 minutes. The control of the flotation time was performed in the same manner as described in Example 1.

(3) Using the evaluation method and evaluation result waters 4-1 to 3, the anionic surfactant (SDS) concentration is kept constant (100 ppm), and the remaining CFU when various additives are added in the above amounts FIG. 7 shows the relationship between the flotation time and FIG. 8 shows the relationship between the remaining TOC and the flotation time.
FIG. 7 shows that the viability removal rate when aluminum flocculant is used tends to be slightly inferior to that when no flocculant is added. In particular, when the aluminum chloride concentration is 50 ppm, it can be seen that the residual CFU rate is almost constant at 20% (removal rate 80%) immediately after the start of MBF, and the removal is not progressing much. The cause of this suggests that the electric charge was just neutralized between the anionic surfactant (SDS) and Al ^{3+ of} aluminum chloride, and a precipitate that did not contribute to inactivation was formed. On the other hand, as shown in FIG. 8, when an aluminum chloride compound was added as a flocculant, both the TOC removal rate and the TOC removal rate after 60 minutes were improved, so that the effect of the flocculant was confirmed to some extent.
As described above, microbubble flotation with the addition of appropriate collection agents, foaming agents, flocculants, and other agents can remove Minamata fungi such as lactic acid bacteria to very low concentrations, and organic substances can also be removed. The sex was confirmed.

[Example 5]
A human hand is immersed in the water in a container in which distilled water is stored, the liquid is cultured with glucose to prepare water to be treated, and microbubbles are generated at the bottom of the container to remove bacteria in the water. Tried.
Bacteria attached to the hands were collected, cultured in a solution of glucose 5 g / L at a predetermined temperature (36 ° C.) for a predetermined time (50 hours), and subjected to flotation as water to be treated. The cell number concentration measured by the ATP method is 9.7 × 10 ⁻⁵ CFU / mL.
As a collecting agent, benzalkonium chloride (BKC) used in Example 1 was added to the water so as to have a concentration of 100 ppm.
Flotation was performed in the same manner as described in Example 1.
FIG. 9 shows the relationship between the ratio of remaining viable bacteria (residual CFU (%) in water) and flotation time (MBF). It can be seen that the proportion of viable bacteria decreased with the progress of MBF, and 90% or more of bacteria were removed from water in 10 minutes and 97% or more of bacteria were removed in 20 minutes or more.
Therefore, according to Example 5, it was confirmed that the “method for removing microorganisms and organic substances in water” of the present invention is also effective in removing germs adhering to the hand.

[Example 6]
In Example 6, the microorganisms were removed in the same manner as in Example 1 except that microorganisms that lived in the drains were cultured and used as microorganisms.
Bacteria collected from a household sink drain were cultured in a 0.5 g / L glucose solution at a predetermined temperature (36 ° C.) for a predetermined time (50 hours) and subjected to flotation as water to be treated. The cell number concentration measured in the same manner is 7.9 × 10 ⁻⁵ CFU / mL.
FIG. 10 shows the relationship between the proportion of viable bacteria remaining in water (residual CFU (%) in water) and flotation time (MBF). Also in this case, when the MBF increased, the proportion of viable bacteria decreased, and it was confirmed that 95% or more of bacteria were removed from water in 20 minutes and 98% or more were removed from water in 30 minutes or more.
Therefore, according to Example 6, it was confirmed that the “method for removing microorganisms and organic substances in water” of the present invention is also effective in removing miscellaneous fungi that live in the drain.

Claims (9)

Flotation of treated water (W1) containing microorganisms (including viruses; the same shall apply hereinafter) or microorganisms and organic substances (excluding microorganisms and viruses; the same shall apply hereinafter) and at least a collector as additive (C) The microbubbles are supplied from the lower part of the flotation machine (FM) to the machine (FM), and the microorganisms or the floated substance in which the microorganisms and organic substances are concentrated from the upper part of the flotation machine (FM) ( U) is levitated and recovered, and the microorganisms or the underflow water (W2) from which the microorganisms and organic substances are removed is collected from a flotation machine (FM).
A method for removing microorganisms and organic substances in water.   The method for removing microorganisms and organic substances in water according to claim 1, wherein the collection agent is a cationic surfactant or an anionic surfactant.   3. The microbial and organic substance in water according to claim 2, wherein the cationic surfactant is one or more selected from amine salt type and quaternary ammonium salt. 4. Removal method.   The method for removing microorganisms and organic substances in water according to claim 2, wherein the anionic surfactant is one or more selected from a carboxylate and a sulfate ester salt. .   The said additive (C) is 1 type (s) or 2 or more types selected from the collection agent, the foaming agent, the flocculant, and the pH adjuster, Any one of Claim 1 to 4 characterized by the above-mentioned. A method for removing microorganisms and organic substances in water according to claim 1.   The method for removing microorganisms and organic substances in water according to any one of claims 1 to 5, wherein the average bubble diameter of the microbubbles supplied to the flotation machine (FM) is 100 µm or less.   The method for removing microorganisms and organic substances in water according to any one of claims 1 to 6, wherein the diameter or major axis of the microorganisms in the treated water (W1) is 10 µm or less. At least, it was composed of a flotation machine (FM), microbubble generation means provided in the lower part of the flotation machine (FM), floated substance recovery means, and underflow water (W2) recovery means, An apparatus for removing the microorganisms or the microorganisms and organic matter from the treated water (W1) containing microorganisms (including viruses; the same shall apply hereinafter) or microorganisms and organic substances (excluding microorganisms and viruses; the same shall apply hereinafter). There,
Water to be treated (W1) and at least a collector as an additive (C) are supplied to a flotation machine (FM), and the microorganisms and organic matter are attached to and floated on the microbubbles generated from the microbubble generating means. Floating material collection means for collecting the floated material (U) is disposed at the upper part of the flotation machine (FM),
Underflow water (W2) recovery means in which the microorganisms, or the microorganisms and organic substances are removed from the water to be treated (W1) is arranged in a flotation machine (FM),
Equipment for removing microorganisms and organic substances in water.   The apparatus for removing microorganisms and organic substances in water according to claim 8, wherein the microbubble generating means is a microbubble generating means utilizing a pore system or a gas-liquid mixing / shearing system.

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