JP2008306939A - Method for culturing and breeding 1,4-dioxane-decomposing bacterium, method for producing carrier for immobilizing 1,4-dioxane-decomposing bacterium, and waste water treating method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for culturing 1,4-dioxane-decomposing bacterium in waste water wherein it is possible to rapidly multiply the bacterium without lowering the activity and to exhibit the excellent decomposing property. <P>SOLUTION: Disclosed is a method provided with an isolation process of isolating the 1,4-dioxane-decomposing bacterium by forming a colony of 1,4-dioxane-decomposing bacterium in an agar medium after seed sludge including 1,4-dioxane-decomposing bacterium is cultured in an inorganic medium containing only 1,4-dioxane as an organic material; and a process of culturing the isolated colony of the 1,4-dioxane-decomposing bacterium in an organic medium containing organic materials except 1,4-dioxane. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for culturing and acclimatizing 1,4-dioxane-degrading bacteria, a method for producing a carrier for immobilizing 1,4-dioxane-degrading bacteria, a wastewater treatment method and apparatus, and in particular, 1,4-dioxane in wastewater is the only one. The present invention relates to a method for culturing and acclimatizing 1,4-dioxane-degrading bacteria to be decomposed and removed as a carbon source, a method for producing a 1,4-dioxane-degrading bacterium-immobilized carrier, a wastewater treatment method and an apparatus.

  1,4-dioxane is generally used as a solvent and is also contained in detergents such as commercially available polyoxyalkyl ethers. For this reason, 1,4-dioxane is contained in the wastewater from the step of producing 1,4-dioxane, or the wastewater from the step of producing or using a polyethylene-based product. However, since 1,4-dioxane is a water-soluble hardly decomposable substance, it can hardly be decomposed by biological treatment or solid-liquid separation treatment in each factory or sewage treatment plant, and there is concern about pollution to the water environment.

  On the other hand, 1,4-dioxane has been detected in a wide range in environmental pollution surveys of designated chemical substances conducted by the Environment Agency, and in particular, pollution in water environments such as rivers and lakes has been reported. In addition, an example in which a high concentration of dioxane was detected from groundwater has been reported.

  And with the revision of the Water Supply Law in April 2004, the content of setting the regulated value of 1,4-dioxane as 0.05 mg / L as a drinking water standard was introduced. For these reasons, there is an increasing need for decomposing and removing 1,4-dioxane in the water environment.

  As a method for decomposing and removing 1,4-dioxane in wastewater, for example, an accelerated oxidation method that promotes the formation of OH radicals by mainly using ozone treatment in combination with hydrogen peroxide treatment and ultraviolet treatment has been proposed ( For example, Patent Documents 1 to 3).

Also known is a Fenton oxidation method in which hydrogen peroxide is added under a metal catalyst to form OH radicals.
JP 2001-029966 A JP 2001-121163 A JP 2000-202466 A

  However, the ozone treatment method and the Fenton oxidation method as described in Patent Documents 1 to 3 have a problem in that the power consumption and the amount of chemicals used are large and the running cost is high.

  On the other hand, the biological treatment can reduce the running cost as compared with the above method, but 1,4-dioxane is a substance that is extremely difficult to decompose, and thus cannot be decomposed and removed by normal biological treatment. .

  Therefore, the inventors of the present application pay attention to a microorganism (1,4-dioxane-degrading bacterium) that efficiently decomposes 1,4-dioxane, and attempt biological treatment using this. However, 1,4-dioxane degrading bacteria have a problem that their growth is extremely slow and culture is difficult.

  The present invention has been made in view of such problems, and is a 1,4-dioxane-degrading bacterium that can be grown at high speed without reducing its activity and can exhibit good 1,4-dioxane-degrading performance. It is an object of the present invention to provide a culture method and a wastewater treatment method and apparatus using an immobilization carrier for 1,4-dioxane degrading bacteria.

  Claim 1 of the present invention is a method for cultivating 1,4-dioxane-degrading bacteria that preferentially degrades 1,4-dioxane in wastewater to achieve the above object, wherein the 1,4-dioxane decomposition An isolation step in which seed sludge containing fungi is cultured in an inorganic medium containing only 1,4-dioxane as an organic substance, and then isolated by forming colonies of the 1,4-dioxane-degrading bacteria on an agar medium; A culture step of culturing an isolated colony of 1,4-dioxane-degrading bacteria in an organic medium containing an organic substance other than 1,4-dioxane, A culture method is provided.

  A 1,4-dioxane-degrading bacterium that decomposes 1,4-dioxane as the only carbon source is known to decompose 1,4-dioxane only in the presence of THF (tetrahydrofuran) (Non-Patent Document Zenlcer, MJetal, (2000) Mineralization of 1,4-dioxixan in the presence of a structural along Biodegradation 11 p239-246). However, since the growth rate of this 1,4-dioxane-degrading bacterium is extremely slow, other microorganisms were easier to prioritize. Moreover, even if 1,4-dioxane was given too much to the number of bacteria, the decomposition rate of 1,4-dioxane-degrading bacteria could not catch up and it was difficult to grow.

  The inventors of the present application give organic substances other than 1,4-dioxane (specifically, easily decomposable organic substances such as peptone, meat extract, glycerin, kaditon, and yeast extract) to the 1,4-dioxane-degrading bacterium. It was found that the growth rate was increased.

  The present invention has been made based on such findings. According to claim 1, the isolation process of 1,4-dioxane degrading bacteria is performed in an inorganic medium containing only 1,4-dioxane as an organic substance. Then, the culture process of 1,4-dioxane degrading bacteria was performed in an organic medium containing an organic substance other than 1,4-dioxane (hereinafter simply referred to as “organic substance”).

  Thereby, it can suppress that the growth of microorganisms other than 1, 4- dioxane decomposing bacteria gives priority, and can make 1, 4- dioxane decomposing bacteria grow efficiently. The seed sludge containing 1,4-dioxane degrading bacteria includes, for example, activated sludge, soil, sludge contained in waste water, and the like. The agar medium is not particularly limited, but a liquid inorganic medium to which agar is added is preferable.

  A second aspect of the present invention is characterized in that in the first aspect, a 1,4-dioxane addition step of adding 1,4-dioxane to the organic medium is provided after the culturing step.

  Although 1,4-dioxane-decomposing bacteria can grow at a high speed by giving organic substances, the activity of 1,4-dioxane-degrading bacteria decreases when only organic substances are given.

  According to claim 2, the activity of 1,4-dioxane-degrading bacteria can be maintained or improved by giving 1,4-dioxane to 1,4-dioxane-degrading bacteria that have been grown to some extent by giving organic substances. it can.

Claim 3 is the process according to claim 2, wherein the step of adding 1,4-dioxane is carried out after the step of culturing until the number of 1,4-dioxane-degrading bacteria reaches 1 × 10 ⁴ cells / mL or more. It is characterized by performing.

  Thereby, a highly active 1,4-dioxane degrading bacterium can be cultured at high speed.

  A fourth aspect of the present invention is characterized in that, in the second or third aspect, the amount of 1,4-dioxane added is 1 to 500 mg / L with respect to the organic medium.

  According to claim 4, since the amount of 1,4-dioxane added is in the above range, the activity can be maintained or improved without hindering the growth of 1,4-dioxane degrading bacteria. In addition, as for the addition amount of 1, 4- dioxane, it is more preferable that it is 10-200 mg / L.

  Claim 5 of the present invention is a method for cultivating 1,4-dioxane degrading bacteria that preferentially degrades 1,4-dioxane in wastewater to achieve the above object, wherein the 1,4-dioxane decomposition An isolation step in which seed sludge containing fungi is cultured in an inorganic medium containing only 1,4-dioxane as an organic substance, and then isolated by forming colonies of the 1,4-dioxane-degrading bacteria on an agar medium; A culture step of culturing an isolated colony of 1,4-dioxane-degrading bacteria in an organic medium containing the 1,4-dioxane and an organic substance other than the 1,4-dioxane; A method for culturing 1,4-dioxane degrading bacteria is provided.

  According to claim 5, since the isolated colonies of 1,4-dioxane-degrading bacteria are cultured in a medium containing both organic matter and 1,4-dioxane, the activity of 1,4-dioxane-degrading bacteria is maintained. Can be grown at high speed.

  A sixth aspect of the present invention is characterized in that the content of the 1,4-dioxane in the organic medium is 1 to 500 mg / L in the fifth aspect.

  Thus, the activity of 1,4-dioxane degrading bacteria can be maintained and more efficiently grown by setting the content of 1,4-dioxane in the organic medium in the above range.

  A seventh aspect of the present invention is characterized in that, in any one of the first to sixth aspects, the organic substance other than the 1,4-dioxane is an easily decomposable organic substance such as peptone, meat extract, glycerin, kaditon, and yeast extract. And

  Claim 8 of the present invention provides a 1,4-dioxane-degrading bacterium-immobilized carrier on which 1,4-dioxane-degrading bacteria that preferentially degrade 1,4-dioxane in wastewater are immobilized in order to achieve the above object. A method for producing 1,4-dioxane, wherein 1,4-dioxane-degrading bacteria cultured by the culture method according to any one of claims 1 to 7 are immobilized on a carrier material A method for producing a carrier for degrading bacteria is provided.

  Claim 9 of the present invention is a 1,4-dioxane-degrading bacterium-immobilized carrier on which 1,4-dioxane-degrading bacteria that preferentially degrade 1,4-dioxane in wastewater are immobilized in order to achieve the above object. And culturing in an inorganic medium containing only 1,4-dioxane as an organic substance, and then immobilizing colonies of 1,4-dioxane degrading bacteria isolated on an agar medium on a carrier material. A method for producing a 1,4-dioxane-degrading bacterium-immobilized carrier is provided.

  According to claim 8 or 9, high activity 1,4-dioxane-degrading bacteria grown at high speed or isolated 1,4-dioxane-degrading bacteria are immobilized on a carrier material. Thereby, the said 1, 4- dioxane decomposing bacteria can be thrown into a processing tank stably and with high density. Examples of the carrier material include a polymer gel and a plastic material.

  A tenth aspect of the present invention is characterized in that, in the eighth or ninth aspect, the 1,4-dioxane-degrading bacterium-immobilized carrier is a entrapping immobilization carrier in which 1,4-dioxane-degrading bacterium is entrapped and immobilized in a polymer gel. To do.

  Claim 11 is a 1,4-dioxane-degrading bacterium immobilization carrier produced by the method for producing a 1,4-dioxane-degrading bacterium immobilization carrier according to any one of claims 8 to 10. provide.

  According to the tenth or eleventh aspect, 1,4-dioxane degrading bacteria can be stably fixed in the polymer gel, and can be charged into the treatment tank at a high density.

  Claim 12 of the present invention is a method for acclimatizing a carrier for immobilizing 1,4-dioxane-degrading bacteria that preferentially degrades 1,4-dioxane in wastewater to achieve the above object, A first step of acclimatizing the 1,4-dioxane-degrading bacterium-immobilized carrier produced by the production method according to any one of 10 with water containing an organic substance other than 1,4-dioxane; And a second step of adding the 1,4-dioxane to the water containing the organic substance after the step of .

  According to claim 12, in the first step, the number of 1,4-dioxane-decomposing bacteria in the immobilization carrier is mainly increased, and in the second step, 1,4-dioxane-decomposing mainly. The activity can be increased. Moreover, even if 1,4-dioxane decomposition activity falls by giving an organic substance in the first step, 1,4-dioxane decomposition activity is supplemented by adding 1,4-dioxane in the second step. be able to.

  As 1,4-dioxane, waste water containing 1,4-dioxane is also included.

  A thirteenth aspect of the present invention is characterized in that in the twelfth aspect, the organic substance other than the 1,4-dioxane is an easily decomposable organic substance such as peptone, meat extract, glycerin, kaditon, and yeast extract.

  Claim 14 of the present invention is a wastewater treatment method for decomposing and removing 1,4-dioxane in wastewater in order to achieve the above object, and the culture method according to any one of claims 1-7. Provided is a wastewater treatment method in which cultured 1,4-dioxane degrading bacteria are added to wastewater, and 1,4-dioxane in the wastewater is decomposed and removed.

  Claim 15 of the present invention is a wastewater treatment method for decomposing and removing 1,4-dioxane in wastewater in order to achieve the above object, wherein the production method according to any one of claims 8 to 10 is used. Provided is a wastewater treatment method in which the produced 1,4-dioxane-degrading bacterium-immobilized carrier is introduced into wastewater, and 1,4-dioxane in the wastewater is decomposed and removed.

  According to claim 14 or 15, by using 1,4-dioxane-degrading bacterium sufficiently proliferated and imparted with activity, or its immobilization carrier, 1,4-dioxane is immediately added to waste water. It can be decomposed and removed.

  Claim 16 of the present invention is a wastewater treatment method for decomposing and removing 1,4-dioxane in wastewater in order to achieve the above object, wherein the production method according to any one of claims 8 to 10 is used. The step of adding the produced 1,4-dioxane-degrading bacterium-immobilized carrier to the wastewater containing 1,4-dioxane, and adding the organic matter other than 1,4-dioxane to the wastewater And a step of culturing 4-dioxane-degrading bacteria.

  According to claim 16, in the wastewater treatment using the 1,4-dioxane-degrading bacterium-immobilized carrier, the organic substance is added, so that the degradation activity of the 1,4-dioxane-degrading bacterium-immobilized carrier is reduced. Even in this case, 1,4-dioxane degrading bacteria in the carrier can be grown.

  A seventeenth aspect is the one according to the sixteenth aspect, wherein the amount of the organic substance added is 1 to 100 mg / L with respect to the wastewater.

  According to claim 17, by adding an organic substance so as to satisfy the above range in waste water, 1,4-dioxane degrading bacteria can be grown in the immobilization carrier, and 1,4-dioxane decomposing activity is exhibited. Can be improved.

  Claim 18 is the addition of 1,4-dioxane according to claim 16 or 17, wherein 1,4-dioxane is added to the wastewater after the step of culturing the 1,4-dioxane-degrading bacterium by adding the organic matter. A process is provided.

  According to the eighteenth aspect, the activity of 1,4-dioxane degrading bacteria in the immobilization carrier can be increased, and the degradation activity can be maintained or improved.

  A nineteenth aspect of the present invention is characterized in that, in any one of the fourteenth to eighteenth aspects, the organic substance other than the 1,4-dioxane is an easily decomposable organic substance such as peptone, meat extract, glycerin, kaditon, and yeast extract. And

  Claim 20 of the present invention is a wastewater treatment apparatus for decomposing and removing 1,4-dioxane in wastewater in order to achieve the above object, and comprehensive immobilization comprising the wastewater and 1,4-dioxane degrading bacteria A treatment tank for decomposing 1,4-dioxane in the wastewater by contacting the carrier; a concentration measuring means for measuring the 1,4-dioxane concentration of the wastewater in the treatment tank; and the inside of the treatment tank And an organic substance addition amount adjusting means for adjusting the addition amount of organic substances other than 1,4-dioxane, and a control means for controlling the organic substance addition amount adjusting means based on the measurement result of the concentration measuring means. A featured waste water treatment apparatus is provided.

  According to the present invention, it is possible to grow at a high speed without reducing the activity, and to exhibit good 1,4-dioxane decomposition performance.

  Hereinafter, preferred embodiments of a method for culturing and acclimatizing 1,4-dioxane-degrading bacteria, a method for producing a carrier for immobilizing 1,4-dioxane-degrading bacteria, a method for treating waste water, and an apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  First, the isolation / culture process of 1,4-dioxane degrading bacteria will be described.

  Since the 1,4-dioxane-degrading bacterium in the present invention has a very low growth rate, it is necessary to prevent other microorganisms from being mixed preferentially in the isolation process. In the culturing step, it is important to give an organic substance to the 1,4-dioxane-degrading bacterium in order to promote the growth of the isolated 1,4-dioxane-degrading bacterium.

  For this reason, the isolation process uses an inorganic medium containing only 1,4-dioxane as the organic substance, and the culture process uses an organic medium mainly containing an organic substance other than 1,4-dioxane. Hereinafter, in the present embodiment, the medium includes not only a gelled medium but also a liquid culture solution.

  In the isolation step, first, seed sludge containing 1,4-dioxane-degrading bacteria (including dioxane) is added to 100-500 mL of medium in which 1,4-dioxane is added to an inorganic medium so that the concentration is 10-100 mg / L. About 500 to 20000 mg / L of sludge collected from the wastewater treatment process is added and cultured. The enrichment culture is preferably performed at 20 to 30 ° C. for about 1 to 3 months.

  The presence of 1,4-dioxane degrading bacteria can be confirmed by measuring a change in 1,4-dioxane concentration in the medium. It is preferable to end the enrichment culture when the rate of decrease in 1,4-dioxane concentration exceeds 50%. The concentration of 1,4-dioxane in the medium can be measured by a known method (Ami Akemi (1997) Environmental Chemistry vol.7 No1 p95-100).

  After completion of the enrichment culture, static culture is performed at a constant temperature of 20 to 35 ° C. in a plate medium in which 10 to 15% of agar is added to the inorganic medium. By confirming the formation of colonies after static culture, 1,4-dioxane-degrading bacteria can be isolated.

  The seed sludge containing 1,4-dioxane-degrading bacteria is not particularly limited as long as it contains 1,4-dioxane, but soil collected from landfill sites, factories and wastewater using 1,4-dioxane. Activated sludge from the treatment plant can be used.

The inorganic substance constituting the inorganic medium is not particularly limited, but inorganic salts (for example, K ₂ HPO ₄ , (NH ₄ ) ₂ SO ₄ , MgSO ₄ .7H ₂ O, FeCl ₃ , CaCl ₂ , NaCl) are preferable. .

  In the culturing step, the 1,4-dioxane degrading bacterium isolated as described above is cultured in an organic medium mainly composed of organic matter.

  As the organic substance, a CGY medium, specifically, an easily decomposable organic substance such as peptone, meat extract, glycerin, kajiton, and yeast extract is preferable. In addition, 1, 4- dioxane may be contained in the said organic substance.

  In the culture, the activity of 1,4-dioxane-degrading bacteria is the highest at about 27 ° C., so the culture temperature is preferably 27 ° C., and the water temperature is preferably about 15-35 ° C., more preferably 20-30 ° C. The culture time is preferably about 5 to 30 days.

  1,4-Dioxane-degrading bacteria are difficult to grow when excessively 1,4-dioxane is given while the number of bacteria is small, whereas 1,4-dioxane-degrading activity is not given when 1,4-dioxane is not given at all. Decreases.

  For this reason, it is preferable to give organic substances other than 1,4-dioxane at the initial stage of culture, and to give 1,4-dioxane in the middle and later stages of culture in which the number of 1,4-dioxane-degrading bacteria has increased to some extent. That is, organic substances other than 1,4-dioxane mainly function to promote the growth of 1,4-dioxane-degrading bacteria, and 1,4-dioxane mainly decomposes 1,4-dioxane-degrading bacteria. It functions to maintain or improve activity.

The addition of 1,4-dioxane is preferably performed when the number of 1,4-dioxane-degrading bacteria becomes 1 × 10 ⁴ cells / mL or more.

  The addition amount of 1,4-dioxane is 1 to 500 mg / L or more, preferably 10 to 200 mg / L or more with respect to the organic medium.

  This is because if 1,4-dioxane is less than 1 mg / L, the effect of restoring the degradation activity of 1,4-dioxane-degrading bacteria is reduced. In addition, when 1,4-dioxane is 200 mg / L or more, the decomposition activity does not change any more, and 1000 mg / L is equivalent to 200 mg / L.

  In addition, in order to discard the medium in a harmless state, it is necessary to make the 1,4-dioxane concentration in the medium as low as possible. For this reason, it is preferable to add 1,4-dioxane little by little according to the number of bacteria of 1,4-dioxane decomposing bacteria and the degree of activity.

  Note that 1,4-dioxane may be contained in the organic medium from the beginning of the culture. In this case, the content of 1,4-dioxane can be the same as described above.

  The cultured 1,4-dioxane-degrading bacterium can be used as it is by putting it into the wastewater containing 1,4-dioxane in the treatment tank as it is. -It is preferable to use what fixed the dioxane degrading microbe to the carrier material.

  Hereinafter, a method for immobilizing 1,4-dioxane degrading bacteria will be described.

  As a method for immobilizing 1,4-dioxane-degrading bacteria, there are mainly an adhesion immobilization method and an entrapment immobilization method. However, since the adhesion immobilization method makes it difficult to stably attach bacteria to a carrier material, entrapment immobilization is possible. It is preferable to adopt a method for forming the same.

  The adhesion-immobilized carrier is obtained by attaching 1,4-dioxane degrading bacteria to a carrier material such as plastic. The carrier material for adhesion is preferably a spherical, square, or cylindrical material such as polyethylene or polypropylene, or a foam or a net-like material. The size of the adhesion-immobilizing carrier is preferably 1 to 10 mm in a sphere equivalent diameter. Further, a granule having a particle size of less than 1 mm can be used.

  The entrapping immobilization carrier is a pellet in which 1,4-dioxane degrading bacteria are entrapped and immobilized in a polymer gel.

  FIG. 1 is a diagram illustrating the flow of a method for producing a entrapping immobilization carrier. As shown in FIG. 1, first, an immobilizing material such as a monomer material or a prepolymer material is mixed with 1,4-dioxane-degrading bacteria, and the pH is adjusted to near neutral (6.5 to 8.5). Prepare the mixed solution. Next, after adding a polymerization initiator such as potassium persulfate to the mixed solution and stirring, the mixture is immediately gelled (polymerized) into a sheet shape or a block shape. The polymerization temperature is preferably 15 to 40 ° C, and more preferably 20 to 30 ° C. The polymerization time is preferably 1 to 60 minutes, and more preferably 10 to 60 minutes. Then, the gelled sheet or block can be cut into a predetermined size (for example, approximately 3 mm square cube) to obtain the entrapping immobilization carrier according to the present invention.

  The monomer material is not particularly limited, but acrylamide, methylenebisacrylamide, triacryl formal and the like can be preferably used.

  Although it does not specifically limit as a prepolymer material, Polyethylene glycol diacrylate, polyethyleneglycol methacrylate, and these derivatives can be used preferably.

  The shape of the entrapping immobilization carrier is not particularly limited, and any shape such as a square shape or a cylindrical shape can be adopted. The size of the entrapping immobilization type carrier is preferably 1 to 10 mm as a sphere equivalent diameter. The production method of the entrapping immobilization carrier is not limited to the above-described method, and a tube forming method, a dropping granulation method, or the like can also be employed.

  Next, the acclimatization method of a 1, 4- dioxane decomposing bacteria immobilization carrier and a wastewater treatment method are explained.

  In addition, although it demonstrates in the example using the entrapping immobilization support | carrier which entrapped and immobilized 1, 4- dioxane decomposing bacteria, it is not limited to this, When using an adhesion | attachment immobilization support | carrier, or 1, 4- dioxane decomposition | disassembly directly It can also be applied when using bacteria.

  Immediately after putting the entrapping immobilization support into the treatment tank, the 1,4-dioxane decomposition performance of the entrapping immobilization support is often low. In order to improve the decomposition activity of 1,4-dioxane to the level of steady operation in a short time, it is preferable to perform a habituation operation.

  The acclimatization operation is preferably performed by adding the above-mentioned organic matter (peptone, meat extract,...) To the wastewater, and after adding the organic matter to increase the number of bacteria, 1,4-dioxane is added. It is more preferable to improve the decomposition activity.

  The amount of the organic substance added is preferably 1 to 100 mg / L, more preferably 1 to 10 mg / L with respect to the wastewater.

  FIG. 2 is a diagram illustrating a schematic configuration of a wastewater treatment apparatus using a entrapping immobilization support for 1,4-dioxane degrading bacteria according to the present invention.

  As shown in FIG. 2, the wastewater treatment apparatus 10 is mainly filled with a entrapping immobilization support 12 according to the present invention, and decomposes 1,4-dioxane in raw water, and the inside of the treatment tank 14. Are provided with an introduction pipe 16 for introducing the raw water and a discharge pipe 18 for discharging the treated water from the treatment tank 14.

  A screen 20 is provided in the treatment tank 14 to prevent the entrapping immobilization carrier 12 from leaking out of the system from the discharge pipe 18.

  Moreover, the density | concentration measurement means 22 which measures the 1, 4- dioxane density | concentration in wastewater, the organic substance storage tank 24 for adding an organic substance in the processing tank 14, and the control means 26 are provided.

  The concentration measuring unit 22 measures the 1,4-dioxane concentration in the wastewater, and the measurement result is output to the control unit 26. The control means 26 adjusts the opening degree of the valve 28 (organic substance addition amount adjusting means) based on the measurement result, so that an appropriate amount of organic substances can be added into the treatment tank 14. In addition, a well-known thing can be used as the density | concentration measurement means 22 (If it is a special method, please describe).

  It is preferable that the filling rate in the treatment tank 14 of the entrapping immobilization carrier 12 of 1,4-dioxane degrading bacteria is 5 to 30%.

  With such a configuration, raw water containing 1,4-dioxane is introduced into the treatment tank 14 from the introduction pipe 16. 1,4-dioxane is decomposed and removed from the raw water in the treatment tank 14 by the action of the entrapping immobilization carrier 12 and discharged from the discharge pipe 18.

  In the acclimatization operation, the concentration measurement means 22 measures the 1,4-dioxane concentration in the wastewater in the treatment tank 14. At this time, when it is determined that the decrease rate of the 1,4-dioxane concentration is small and the decomposition activity is low, the opening degree of the valve 28 is adjusted by the control means 26, and the organic matter is added into the treatment tank 14.

  Since the activity of 1,4-dioxane degrading bacteria is the highest at about 27 ° C, the acclimatization temperature is preferably 27 ° C, and the water temperature is preferably about 15-35 ° C, more preferably 20-30 ° C. The acclimatization is preferably performed until the decomposition rate of 1,4-dioxane reaches a steady operation level.

  By using the entrapped immobilization carrier acclimatized in this way, the decomposition performance of 1,4-dioxane in wastewater can be increased to the level of steady operation in a short time, and high decomposition performance can be maintained.

  The steady operation can be performed in the same temperature range as the acclimatization operation described above. The pH in the wastewater is not particularly limited, but is preferably near neutral.

  Thereby, 1, 4- dioxane decomposition | disassembly activity can be started at an early stage and high decomposition activity can be maintained also in steady operation.

  FIG. 3 is a diagram illustrating another aspect of the wastewater treatment apparatus in the present invention. Note that members having the same functions as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  3 further includes a tank 30 for storing 1,4-dioxane, and a valve 34 for adjusting the amount of 1,4-dioxane added. The configuration is substantially the same as that shown in FIG. 2 except that the control means 32 for controlling the amount of 4-dioxane added is provided.

  The control means 32 can adjust the opening degree of the valves 28 and 34 based on the measurement result of the concentration measurement means 22 and can add an appropriate amount of organic matter or 1,4-dioxane into the treatment tank 14. ing.

  Thereby, after adding organic substance and increasing the number of 1, 4- dioxane decomposing bacteria in processing tank 14, 1, 4- dioxane can be further added and decomposition activity can be improved. Therefore, 1,4-dioxane decomposing activity can be started at an early stage, and high decomposing activity can be maintained even in steady operation.

  It should be noted that the above method can be applied when 1,4-dioxane decomposition activity is reduced not only in a habituation operation but also in a steady operation.

As described above, by applying the method for culturing and acclimatizing 1,4-dioxane-degrading bacteria of the present invention, the method for producing a carrier for immobilizing 1,4-dioxane-degrading bacteria, and the method for treating wastewater, 1,4-dioxane, which has been difficult to decompose, can be biologically decomposed and removed. Specifically, the decomposition rate of 1,4-dioxane per 1 m ³ of the treatment tank can be 10 g or more per day, that is, 10 g / m ³ / day or more.

  The preferred embodiments of the method for culturing and acclimatizing 1,4-dioxane-degrading bacteria, the method for producing a carrier for immobilizing 1,4-dioxane-degrading bacteria, the method for treating waste water and the apparatus according to the present invention have been described above. It is not limited to the said embodiment, Various aspects can be taken.

  Although the said embodiment demonstrated the example used after culture | cultivating the isolated 1, 4- dioxane degrading microbe until it becomes a certain level bacterial count, it uses as a comprehensive fixed support | carrier, it is not limited to this. For example, even when an isolated 1,4-dioxane-degrading bacterium is used as a entrapping immobilization support without sufficiently culturing, the degradation performance of 1,4-dioxane can be improved by acclimatizing the entrapping immobilization support as described above. It can be increased in a short time. In short, before using the isolated 1,4-dioxane itself or its immobilization support in steady operation, at least an organic substance other than 1,4-dioxane is given to grow 1,4-dioxane-degrading bacteria. In addition, 1,4-dioxane may be given to maintain or improve the decomposition activity.

  In the above embodiment, an example in which the entrapping immobilization support is prepared and then conditioned with wastewater containing 1,4-dioxane and then continuously operated in the same treatment tank has been described. After acclimatization in the tank, it can be transferred to another processing tank that is in steady operation.

  In the above embodiment, the culturing step, the entrapping immobilization carrier, and the wastewater treatment step (acclimation operation, steady operation) have been described, but these steps may be performed individually or in any combination. In particular, in the culture process, 1,4-dioxane-degrading bacteria are artificially cultured, and in the acclimatization process, 1,4-dioxane-degrading bacteria or entrapping immobilization carriers thereof are applied to the properties and operating conditions of waste water. As shown in the block diagram of FIG. 4, it is preferable to perform all the above steps.

[Example 1]
Activated sludge from a wastewater treatment plant in a chemical factory was collected, and concentrated culture was performed using a medium obtained by adding 1,4-dioxane to a liquid inorganic medium shown in Table 1 to 100 mg / L. In addition, pH of the inorganic culture medium of Table 1 was 7.0.

  After enrichment culture at 26 ° C. for about 6 months, the concentration of 1,4-dioxane in the culture medium was measured. As a result, a decrease in the 1,4-dioxane concentration was confirmed. The activity of the fungus was confirmed.

  Subsequently, 15% of agar was added to the liquid inorganic medium shown in Table 1 and solidified at room temperature to obtain a flat plate medium, and 1,4-dioxane degrading bacteria were isolated. And several types of colonies were formed, and 1,4-dioxane degrading bacteria could be isolated.

  Further, this colony was put into a 1 L Erlenmeyer flask, 500 mL of an inorganic medium was injected, and 1,4-dioxane was added so as to be 50 mg / L. Then, it culture | cultivated at 26 degreeC for 1 month, and the fungal culture liquid of 1, 4- dioxane decomposing bacteria was obtained.

The 1,4-dioxane-degrading bacterium thus isolated and cultured was added to the medium having each composition shown in Table 3 so as to be 1.2 × 10 ⁴ cells / mL, and a culture test was performed. As culture conditions, 100 mL of each medium (liquid) shown in Table 3 was poured into a 300 mL Erlenmeyer flask and incubated at 27 ° C. while soaking. Five days after the start of culture, the bacterial concentration in the culture was measured. Table 2 shows the composition of the CGY medium (organic medium). The result is shown in FIG.

As shown in FIG. 5, the number of 1,4-dioxane-degrading bacteria 5 days after the start of culture is 9.1 × 10 ⁴ cells / mL in Test 1 and 4.2 × 10 ⁶ cells in Test 2. It was 4.0 × 10 ⁶ cells / mL in Test 3. Thus, it was found that 1,4-dioxane-degrading bacteria can be cultured at a high speed by adding organic substances to the medium and culturing.

  Next, the 1,4-dioxane degrading activity of 1,4-dioxane degrading bacteria cultured in tests 1, 2, and 3 was evaluated.

  The cultured 1,4-dioxane degrading bacteria were collected by precipitation with a centrifugal concentrator. Using this 1,4-dioxane-degrading bacterium, a 1,4-dioxane-decomposing test was conducted.

In the test, 50 mL of an inorganic medium containing 100 mg / L of 1,4-dioxane was injected into a 200 mL Erlenmeyer flask. Three systems were prepared, and 1,4-dioxane-degrading bacteria cultured in tests 1, 2, and 3, respectively, were injected into each system so as to be 1 × 10 ⁴ cells / mL.

  Next, the above three systems were cultured for 5 days in a constant temperature room at 27 ° C. Thereafter, the 1,4-dioxane concentration remaining in each system was measured, and the 1,4-dioxane removal rate was determined from the following formula.

1,4-dioxane removal rate (%) = (1,4-dioxane concentration before test−1,4-dioxane concentration after test) / (1,4-dioxane concentration before test) × 100
The results are shown in Table 4.

  As shown in Table 4, the test 2 in which both 1,4-dioxane and an organic substance were added and cultured was able to most proliferate 1,4-dioxane-degrading bacteria, and the decomposition activity of 1,4-dioxane was also I found it expensive.

[Example 2]
Three types of entrapping immobilization carriers were prepared based on the following composition using 50 mL of a bacterial culture solution in which 1,4-dioxane-degrading bacteria were cultured.

(Composition of entrapping immobilization carrier)
Number of 1,4-dioxane-degrading bacteria: 2 × 10 ⁵ cells / mL
Immobilization material: Acrylamide 15% by mass
Polymerization accelerator: NNN'N 'tetramethylethylenediamine 0.5% by mass
Polymerization initiator: Potassium persulfate 0.25% by mass
As described above, 1,4-dioxane degrading bacteria were added to and mixed with the immobilization material (acrylamide solution) to prepare a suspension. Next, potassium persulfate and NNN′N ′ tetramethylethylenediamine were added to the suspension to cause gelation (polymerization) at a polymerization temperature of 10 ° C. and a polymerization time of 5 minutes. And the gelatinized support | carrier was shape | molded to the spherical shape of about 3 mm diameter, and was pelletized, and, thereby, the comprehensive fixed support | carrier of this example was produced.

  Each entrapping immobilization support produced in this way was conditioned with each waste water shown in Table 4. The acclimatization operation was carried out for 30 days with a water temperature of 27 ° C. and a residence time of 1 day. Then, on the 31st day, each entrapping immobilization support was transferred to a waste water in which 1,4-dioxane was added at 100 mg / L to the inorganic medium shown in Table 1, and a steady operation was performed. The 1,4-dioxane removal rate at this time was measured, and the treatment performance of 1,4-dioxane degrading bacteria was evaluated. The 1,4-dioxane concentration was measured by the GC / MS method. The results are shown in Table 5.

  As shown in Table 5, the entrapping immobilization support of Test 4 that was conditioned in wastewater containing organic matter and added with 1,4-dioxane had the highest 1,4-dioxane removal rate of 95% in steady operation. It was. Moreover, the removal rate of 1,4-dioxane was relatively good at 52% even in the entrapping immobilization support of Test 3 that was conditioned in wastewater to which 1,4-dioxane was added without adding organic substances.

  On the other hand, the entrapping immobilization support of Test 5 conditioned with waste water not containing 1,4-dioxane had the lowest 1,4-dioxane removal rate of 5% in steady operation.

  Subsequently, steady operation was performed, and on day 40, the 1,4-dioxane removal rate of the entrapping immobilization support of Test 5 increased to 95%, and the entrapping immobilization support of Test 3 had a 1,4-dioxane removal rate of 70%. Rose to%.

  From the above, it was found that the entrapping immobilization support of Test 4 to which both the organic substance and 1,4-dioxane were given by a habituation operation showed the fastest rise in treatment performance and high decomposition activity. In addition, it was found that the entrapping immobilization support of Test 3 to which the organic substance was given by the habituation operation showed higher decomposition activity (treatment performance) than the entrapping immobilization support of Test 5 which was not given the organic substance by the habituation operation. .

  As described above, it was found that by applying the present invention, the rise of the decomposition performance of 1,4-dioxane can be accelerated and high decomposition activity is exhibited.

It is a figure explaining the flow of the manufacturing method of the comprehensive fixed support | carrier which concerns on this invention. It is a figure explaining schematic structure of the wastewater treatment equipment concerning the present invention. It is a figure explaining another aspect of the wastewater treatment equipment concerning the present invention. It is a block diagram which shows the process in this invention. It is a graph which shows the result of the culture test in a present Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Waste water treatment apparatus, 12 ... Comprehensive immobilization support | carrier, 14 ... Treatment tank, 16 ... Introducing piping, 18 ... Discharge piping, 20 ... Screen, 22 ... 1, 4- dioxane density | concentration measuring means, 24 ... Organic substance storage tank, 26 , 32 ... control means, 28, 34 ... valve, 34 ... 1,4-dioxane storage tank

Claims (20)

A method for culturing 1,4-dioxane degrading bacteria that preferentially degrades 1,4-dioxane in waste water,
The seed sludge containing 1,4-dioxane-degrading bacteria is cultured in an inorganic medium containing only 1,4-dioxane as an organic substance, and then isolated by forming colonies of the 1,4-dioxane-degrading bacteria on an agar medium. An isolation step to
A culture step of culturing the isolated colony of 1,4-dioxane-degrading bacteria in an organic medium containing an organic substance other than 1,4-dioxane;
A method for culturing 1,4-dioxane degrading bacteria, comprising:   The method for culturing 1,4-dioxane-degrading bacteria according to claim 1, further comprising a 1,4-dioxane addition step of adding 1,4-dioxane to the organic medium after the culturing step. 3. The 1,4-dioxane addition step is performed after the culturing step until the number of 1,4-dioxane degrading bacteria reaches 1 × 10 ⁴ cells / mL or more. 1. The method for culturing 1,4-dioxane degrading bacteria described in 1.   The method for culturing 1,4-dioxane-degrading bacteria according to claim 2 or 3, wherein the amount of 1,4-dioxane added is 1 to 500 mg / L with respect to the organic medium. A method for culturing 1,4-dioxane degrading bacteria that preferentially degrades 1,4-dioxane in waste water,
The seed sludge containing 1,4-dioxane-degrading bacteria is cultured in an inorganic medium containing only 1,4-dioxane as an organic substance, and then isolated by forming colonies of the 1,4-dioxane-degrading bacteria on an agar medium. An isolation step to
Culturing the isolated colony of 1,4-dioxane-degrading bacteria in an organic medium containing the 1,4-dioxane and an organic substance other than the 1,4-dioxane;
A method for culturing 1,4-dioxane degrading bacteria, comprising:   6. The method for culturing 1,4-dioxane-degrading bacteria according to claim 5, wherein the content of 1,4-dioxane in the organic medium is 1 to 500 mg / L.   The organic substance other than the 1,4-dioxane is an easily decomposable organic substance such as peptone, meat extract, glycerin, kaditon, yeast extract and the like, according to any one of claims 1 to 6. , 4-Dioxane degrading bacteria culture method. A method for producing a 1,4-dioxane-degrading bacterium-immobilized carrier on which 1,4-dioxane-degrading bacterium that preferentially degrades 1,4-dioxane in wastewater is immobilized,
Production of 1,4-dioxane-decomposing bacteria-immobilized carrier, wherein 1,4-dioxane-degrading bacteria cultured by the culture method according to any one of claims 1 to 7 are immobilized on a carrier material. Method. A method for producing a 1,4-dioxane-degrading bacterium-immobilized carrier on which 1,4-dioxane-degrading bacterium that preferentially degrades 1,4-dioxane in wastewater is immobilized,
A 1,4-dioxane-decomposing colony isolated on an agar medium after culturing in an inorganic medium containing only 1,4-dioxane as an organic substance is immobilized on a carrier material. A method for producing a carrier for immobilizing dioxane-degrading bacteria.   The 1,4-dioxane-degrading bacterium-immobilized carrier is a entrapping immobilization carrier in which 1,4-dioxane-degrading bacterium is entrapped and immobilized in a polymer gel. A method for producing a 4-dioxane-degrading bacterium-immobilized carrier.   A 1,4-dioxane-degrading bacterium-immobilized carrier produced by the method for producing a 1,4-dioxane-degrading bacterium-immobilized carrier according to any one of claims 8 to 10. A method for acclimatizing a carrier for immobilizing 1,4-dioxane-degrading bacteria that preferentially degrades 1,4-dioxane in waste water,
A first step of acclimatizing the 1,4-dioxane-degrading bacterium-immobilized carrier produced by the production method according to any one of claims 8 to 10 with water containing an organic substance other than 1,4-dioxane. ,
A second step of adding the 1,4-dioxane to the water containing the organic matter after the first step;
A method for acclimatizing a carrier for immobilizing 1,4-dioxane-degrading bacteria, comprising:   The organic substance other than the 1,4-dioxane is an easily degradable organic substance such as peptone, meat extract, glycerin, kadhiton, yeast extract, etc., How to acclimatize chemical carriers. A wastewater treatment method for decomposing and removing 1,4-dioxane in wastewater,
A wastewater treatment method in which 1,4-dioxane-degrading bacteria cultured by the culture method according to any one of claims 1 to 7 are introduced into wastewater, and 1,4-dioxane in the wastewater is decomposed and removed. A wastewater treatment method for decomposing and removing 1,4-dioxane in wastewater,
A wastewater treatment method in which the 1,4-dioxane-degrading bacterium-immobilized carrier produced by the production method according to any one of claims 8 to 10 is introduced into wastewater, and 1,4-dioxane in the wastewater is decomposed and removed. . A wastewater treatment method for decomposing and removing 1,4-dioxane in wastewater,
A step of introducing the 1,4-dioxane-degrading bacterium-immobilized carrier produced by the production method according to any one of claims 8 to 10 into waste water containing the 1,4-dioxane;
Culturing the 1,4-dioxane degrading bacterium by adding an organic substance other than the 1,4-dioxane to the waste water;
A wastewater treatment method characterized by comprising:   The wastewater treatment method according to claim 16, wherein the addition amount of the organic substance is 1 to 100 mg / L with respect to the wastewater.   The method according to claim 1, further comprising a 1,4-dioxane addition step of adding 1,4-dioxane to the waste water after the step of culturing the 1,4-dioxane degrading bacterium by adding the organic matter. The wastewater treatment method according to 16 or 17.   The wastewater according to any one of claims 14 to 18, wherein the organic substance other than 1,4-dioxane is an easily decomposable organic substance such as peptone, meat extract, glycerin, kaditon, and yeast extract. Processing method. A wastewater treatment apparatus for decomposing and removing 1,4-dioxane in wastewater,
A treatment tank for decomposing 1,4-dioxane in the wastewater by contacting the wastewater with a entrapping immobilization support containing 1,4-dioxane degrading bacteria;
Concentration measuring means for measuring the 1,4-dioxane concentration of wastewater in the treatment tank;
Organic substance addition amount adjusting means for adjusting the addition amount of organic substances other than 1,4-dioxane in the treatment tank;
Control means for controlling the organic substance addition amount adjusting means based on the measurement result of the concentration measuring means,
A wastewater treatment apparatus characterized by comprising:

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