JP4284560B2 - Volume reduction method for entrapping immobilization carrier, entrapping immobilization carrier, water purification method, and entrapping immobilization carrier manufacturing apparatus - Google Patents

Description

  The present invention relates to a method for reducing the volume of a entrapping immobilization support, a entrapping immobilization support, a water purification method, and an apparatus for producing a entrapping immobilization support, and more particularly, a microorganism inclusion of a hydrous gel for purifying the quality of breeding water such as ornamental fish The present invention relates to a technique for reducing the volume of an immobilized carrier.

  Nitrifying bacteria contained in activated sludge used for wastewater treatment have a slower growth rate than general bacteria, and the number of bacteria decreases particularly during the low water temperature period in winter. This phenomenon is also observed in microorganisms having the same properties as nitrifying bacteria. For this reason, activated sludge containing nitrifying bacteria is attached to the surface of adhesive materials such as sponges and plastics to increase the concentration of nitrifying bacteria and improve the nitrification performance of wastewater (reference: water treatment by microbial immobilization method) Carrier immobilization method, comprehensive immobilization method, biological activated carbon method, NTS Co., Ltd., issued in 2000). However, microorganisms are peeled off from the adhering material, or microorganisms different from the target nitrifying bacteria are adhered to the carrier, so that the concentration of nitrifying bacteria cannot be sufficiently increased.

  For this reason, a entrapping immobilization carrier that entraps and immobilizes useful microorganisms such as nitrifying bacteria in an immobilization material has been proposed. By filling this entrapping immobilization carrier into a treatment tank to increase the concentration of nitrifying bacteria, nitrification activity is improved and wastewater is treated at high speed (for example, Patent Document 1). The entrapping immobilization carrier is produced by mixing activated sludge with an immobilization material such as a polymer compound to prepare a raw material liquid, and polymerizing the raw material liquid with a polymerization initiator to form a gel. The produced entrapping immobilization carrier is stored and transported in a bag or case together with some water, taken out from the bag or case at a place where there is a wastewater treatment facility, and put into a treatment tank for use.

  By the way, an unpolymerized material of the immobilization material may adhere to the surface of the entrapping immobilization carrier. For this reason, when the carrier is dried, the unpolymerized material on the carrier surface becomes sticky, and the carriers tend to adhere to each other to form a dumpling-like lump. When such a dumpling-like lump is generated, the lump is not easily broken even if it is brought into contact with waste water in the treatment tank, and the original performance cannot be exhibited. For this reason, when storing and transporting the entrapping immobilization carrier, the entrapping immobilization carrier and water are put into a case or a bag so that the carriers do not directly contact each other.

  As described above, when the entrapping immobilization carrier is immersed in water in a bag or case and stored and transported, the capacity and weight increase, and therefore, there is a problem that it takes time and cost for storage and transport. For this reason, there is a demand for a method that can be stored and transported without causing lumps even if water is not put into the bag or case. In addition, the moisture content of the entrapping immobilization carrier is usually as high as about 80 to 95%, and it is required to reduce (decrease) the size of the entrapping immobilization carrier by dehydration.

On the other hand, for example, the applicant of the present application has proposed a method of reducing the volume of the carrier by introducing the entrapping immobilization carrier into heated warm water and shrinking the hydrated gel of the entrapping immobilization carrier (patent). Reference 2).
Patent No. 3422229 JP 2004-298701 A

  However, in Patent Document 2 described above, for example, since the hydrated gel of the carrier is thermally contracted by immersing the carrier in heated warm water, the volume reduction of the carrier is only the shrinkage of the hydrated gel, and the significant volume reduction effect is It was not obtained.

  In addition, when the carrier is heated at a relatively high temperature, the shape of the carrier is not easily lost due to rapid drying, and microorganisms held in the carrier are easily damaged by heat, which may reduce the activity of the microorganisms.

  The present invention has been made in view of such circumstances, and is a comprehensive immobilization carrier that can effectively reduce the volume of a carrier while maintaining a uniform carrier shape without reducing the activity of microorganisms held in the carrier. An object of the present invention is to provide a volume reduction method, a entrapping immobilization support, a water purification method, and a entrapping immobilization support manufacturing apparatus.

In order to achieve the above object, claim 1 of the present invention is a method for reducing the volume of a entrapping immobilization support in which microorganisms are entrapped and immobilized inside an immobilization material, wherein the surface temperature of the entrapping immobilization support is 10 to 40. A method for reducing the volume of a entrapping immobilization carrier , comprising a step of reducing the volume by air drying so that the temperature becomes 0 ° C. provide.

  According to claim 1, since the entrapping immobilization support is blown and dried at 10 to 40 ° C., the entire entrapping immobilization support is uniformly and gently dried without damaging the microorganisms held in the support by heat. (Reducing moisture content). As a result, the volume of the carrier can be reduced while maintaining a uniform carrier shape without reducing the activity of the microorganisms held in the carrier. That is, if the carrier surface is blown and dried so that the surface temperature is less than 10 ° C., the activity of the microorganisms is reduced because the temperature is too low. If the carrier is blown and dried so that the temperature exceeds 40 ° C., the activity of the microorganisms is damaged by heat. , Both of which are not preferable. Therefore, it is necessary to blow and dry so that the temperature of the surface of the carrier is 10 to 40 ° C, preferably 20 to 30 ° C. Examples of microorganisms include, but are not limited to, mesophilic bacteria mainly used in wastewater treatment. Among them, microorganisms that are easily damaged by heat, such as ammonia oxidizing bacteria, nitrite oxidizing bacteria, organic matter decomposing bacteria, denitrification Examples include bacteria.

In addition, since the moisture content of the entrapping immobilization carrier is blown and dried until the moisture content becomes 1 to 5%, the surface of the carrier becomes sticky due to unpolymerized material while ensuring the moisture necessary for the microorganisms in the carrier to survive. It can be dried to such an extent that it does not. In addition, by drying by blowing the moisture content to 1 to 5%, the volume can be significantly reduced to about 1/10 of the water content before drying by blowing.

  The moisture content can be determined from the ratio of the carrier weight to the carrier weight when dried at 105 ° C. for 6 hours with the moisture content being 0%. For example, when the carrier weight when the moisture content is 0% is 30 mg and the carrier weight when the moisture content is 33 mg, the moisture content of the carrier at this time is ((33-30) mg / 33 mg) × 100 = 9% It becomes.

Claim 2 in claim 1, a specific surface area of the entrapping immobilization pellets prior to the blowing drying characterized in that it is a 1200~6000m ² / ^{m 3.}

If the specific surface area is too small, it is difficult to dry because the contact area with the drying air is small, and stickiness due to unpolymerized material on the surface of the carrier tends to occur. On the other hand, if the specific surface area is too large, the contact area with the drying air is large, and the shape of the carrier tends to collapse due to rapid drying. According to the second aspect , since the specific surface area of the entrapping immobilization support is 1200 to 6000 m ² / m ³ , drying can be performed in a short time while maintaining the shape of the support without causing the above problems. Can do.

Claim 3 is Claim 1 or 2 , wherein the immobilization material is an acrylate or diacrylate derivative of a polymer comprising ethylene oxide and propylene oxide, and the molecular weight of the acrylate or diacrylate derivative is 1000 to 10,000. It is characterized by that.

In the case of low molecular weight materials such as acrylamide, moisture in the hydrogel is easily removed by blow drying, and if the molecular weight is greater than 10,000, it is difficult to dry and it is difficult to adjust the water content. According to claim 3 , since the immobilization material is an acrylate or diacrylate derivative of a polymer composed of ethylene oxide and propylene oxide, and the molecular weight of the acrylate or diacrylate derivative is 1000 to 10,000. In addition, it is possible to prevent the shape of the carrier from collapsing due to drying, and to easily adjust the carrier to an appropriate moisture content range.

A fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, the microorganism is contained in 10 ⁵ cells / mL or more in the entrapping immobilization support before being blown and dried.

According to claim 4 , since microorganisms are immobilized in a large amount of 10 ⁵ cells / mL or more, even when the activity tends to decrease slightly due to a decrease in water content, the treatment efficiency of waste water is significantly reduced. Can be suppressed. A fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, the time for blowing and drying is 12 hours to 24 hours. In addition, drying time can also be shortened by lowering humidity and carrying out ventilation drying.

  Claim 6 of the present invention is a entrapping immobilization carrier in which microorganisms are entrapped and immobilized inside an immobilization material in order to achieve the object, and the entrapping immobilization according to any one of claims 1 to 5 Provided is a entrapping immobilization carrier characterized in that it is reduced in volume by a carrier volume reduction method.

  According to the sixth aspect, it is possible to obtain a volume-reducing carrier having a uniform shape without a decrease in microbial activity.

  In order to achieve the above object, claim 7 of the present invention provides a water purification method characterized in that the entrapping immobilization carrier of claim 6 is immersed in water and swollen and then used for water purification. .

  According to claim 7, by immersing the volume-immobilized immobilization carrier in water, it can be returned to the water-containing gel state before drying. For example, breeding water such as ornamental fish, river / lake water, It can be used for water purification such as industrial wastewater.

  Claim 8 of the present invention is an apparatus for producing a entrapping immobilization carrier in which microorganisms are entrapped and immobilized inside an immobilization material to achieve the above object, and a preparation unit for preparing a mixture of the microorganism and the immobilization material A molded part that is molded by polymerizing the prepared mixture, a cutting part that is cut into a predetermined size by cutting the molded body into a predetermined size, and a predetermined temperature with respect to the comprehensive fixed carrier And a blower drying section for blowing and drying with a entrapping immobilization support manufacturing apparatus.

  A ninth aspect of the present invention is the method according to the eighth aspect, wherein the ventilation drying unit is configured to measure a surface temperature of the entrapping immobilization support, and a temperature adjustment unit that adjusts the ventilation temperature based on a result of the measurement unit; It is provided with.

  According to the ninth aspect, since the temperature adjusting means for adjusting the blowing temperature is provided based on the measurement result of the measuring means, the blowing temperature can be accurately controlled so that the temperature of the surface of the carrier falls within a predetermined range.

  According to the present invention, the carrier can be effectively reduced while maintaining a uniform carrier shape without reducing the activity of the microorganisms held in the carrier.

  Hereinafter, preferred embodiments of the volume-reducing method for a entrapping immobilization carrier according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a flow from a manufacturing process to a use process of a carrier to which the present invention is applied.

  As shown in FIG. 1, the entrapping immobilization carrier produced in the production process 12 is reduced in volume in the volume reduction process 14, transported to the place where it is used in the storage / transport process 16, and then entrapped in the return process 18. The carrier is immersed in water to return to its original size and used for water purification in the biological treatment step 19.

  In the manufacturing process 12, as shown in FIG. 2, first, microorganisms such as activated sludge and an immobilizing material are mixed and stirred well to prepare a raw material solution. Then, a polymerization initiator such as potassium persulfate is added to the raw material solution and polymerized. At this time, the polymerization temperature is preferably 15 to 40 ° C, more preferably 20 to 30 ° C. The polymerization time is preferably 1 to 60 minutes, and more preferably 1.5 to 60 minutes. Thereafter, the carrier that has been polymerized and gelled is cut into, for example, a square shape of about 3 mm square, whereby a entrapping immobilization carrier can be obtained.

The size of the entrapping immobilization carrier (hereinafter also simply referred to as “carrier”) is set so that the specific surface area is 1200 to 6000 m ² / m ³ so that air can be uniformly blown to the surface of the carrier in the volume reduction step 14 described later. It is preferred that Further, since the water content of the carrier by air drying decreases, so it is highly efficient processing even activity is reduced in microorganisms in the carrier, it is preferable to fix the high levels of microorganisms, for example, 10 ⁵ cells / mL or more.

  The microorganism is not limited to activated sludge, and a purely cultured microorganism may be used. Examples of the type of microorganism include BOD component oxidizing bacteria, dioxin degrading bacteria, bisphenol A degrading bacteria, blue-tailed degrading bacteria, nitrifying bacteria, denitrifying bacteria, anaerobic ammonia oxidizing bacteria, and the like. In particular, the present invention is suitable for microorganisms that are easily damaged by heat, and examples include ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, organic matter-decomposing bacteria, and denitrifying bacteria.

  The immobilization material is not particularly limited, and for example, polyethylene glycol-based or polyvinyl alcohol-based polymers are used. Specifically, the content ratio of ethylene oxide and propylene oxide is 7: 3, and the end group is A prepolymer having a molecular weight of 1000 to 10,000 which is diacrylate can be used. In addition, polyethylene glycol acrylate, polyethylene glycol diacrylate, polyethylene glycol methacrylate, and the like can also be used.

  The molding method is not particularly limited, and a block molding method, a sheet molding method, a tube molding method, a dropping granulation method, and the like can be employed.

  In the volume reduction process 14, the carrier produced in the production process 12 is reduced in volume by air drying at a predetermined temperature.

  At this time, it is important to dry at a temperature at which the microorganisms in the carrier are not inactivated by heat. That is, when the blast temperature is less than 10 ° C., the temperature is too low and the activity of the microorganism is decreased, and when it exceeds 40 ° C., the activity of the microorganism is decreased due to heat damage. For this reason, blowing temperature is set so that the surface temperature of a support | carrier may be 10-40 degreeC, Preferably it is 20-30 degreeC.

  Further, since the shape of the carrier tends to collapse when the drying rate is too high, it is also important to dry gently (decrease the drying rate). Although drying time is not specifically limited, For example, it is preferable to set it as 12 to 24 hours. From the viewpoint of shortening the drying time, the dehumidified drying air can be supplied to the entrapping immobilization carrier.

  In the volume reduction process 14, it is necessary to dry the surface of the carrier to such an extent that no stickiness due to the unpolymerized material is generated, while ensuring the moisture necessary for the survival of the microorganisms in the carrier. In other words, if the moisture content is less than 1%, the moisture necessary for the microorganism is insufficient, and the activity of the microorganism tends to decrease. If the moisture content exceeds 5%, the dried carrier surface becomes sticky and becomes a lump and is immersed in water. Even if the mass does not collapse, the activity of the microorganisms decreases. Therefore, it is preferable to blow dry until the moisture content of the carrier is 1 to 5%, and more preferably blow dry to 3 to 5%.

  The moisture content can be determined from the ratio of the carrier weight to the carrier weight when dried at 105 ° C. for 6 hours with the moisture content being 0%.

  In the storage / transportation step 16, the carrier reduced and dried in the volume reduction step 14 is packed into a storage container such as a bag or a case and transported. And the returned process 18 is performed by taking out the conveyed support | carrier from a storage container and throwing into the biological treatment tank of a wastewater treatment facility.

  In the returning step 18, the carrier is immersed in water for a predetermined time to return the carrier to the shape (volume) before volume reduction. The time for immersing the carrier in water varies depending on the dry state of the carrier and the material used, but is preferably about 12 to 24 hours. Alternatively, water may be stored in a water tank different from the biological treatment tank, and the returning step may be performed by immersing the carrier in this water. After the returning step 18, the biological treatment step 19 can be performed by introducing raw water into the biological treatment tank.

  As described above, in the storage / transportation process, conventionally, water is poured into the case and the carrier is immersed and stored in water, so that the bulk volume and the weight are both large and handling is not good. In addition, when the storage temperature is high, the water in the storage container tends to rot and sometimes gives off a bad odor. This foul odor was due to the elution of organic substances and adhering organic substances from the carrier into water, causing the microorganisms to propagate and decay.

  According to the present invention, in the volume reduction step 14, the volume of the carrier can be reduced by drying while maintaining a uniform carrier shape without reducing the activity of the microorganisms held in the carrier. For this reason, it is not necessary to put water in a bag or a case, and the carrier can be stored and transported in a dry state and compactly. Thereby, while handling at the time of storage and conveyance can be improved significantly, malodor can also be prevented.

  Next, an apparatus configuration for carrying out the volume reduction method for the entrapping immobilization carrier according to the present invention will be described.

  FIG. 3 is a schematic diagram showing the configuration of the carrier manufacturing apparatus 20 according to the present invention. The carrier manufacturing apparatus 20 mainly includes a raw material preparation unit 22, a molding unit 24, a cutting unit 26, and a blower drying unit 28.

  The raw material preparation unit 22 mainly includes a raw material tank 32 in which raw materials are stored, chemical tanks 34 and 36 in which chemicals such as an immobilizing material solution and a polymerization initiator are stored, and agitation / extrusion for mixing raw materials and chemicals. Device 38. The pumps 40, 42, and 44 are respectively provided as drive means for introducing the raw material in the raw material tank 32, the chemical in the chemical tank 34, and the chemical in the chemical tank 36 into the stirring / extruding device 38. As a result, the mixed liquid as a raw material for producing the entrapping immobilization carrier can be mixed in the stirring / extruding device 38 and extruded to the molding frame 46.

  The molding unit 24 mainly includes a molding frame 46 that produces a molded body 48 by polymerizing the mixed solution, and a moving stage 50 that conveys the molding frame 46. The molding frame 46 is provided with temperature adjusting means 52 so that the polymerization temperature can be adjusted.

  The cutting unit 26 mainly includes a fixed stage 54 that fixes the molded body 48, and an extrusion plate 58 that is provided on one end side of the fixed stage 54 and that is movable by the transport mechanism 56. A grid-like cutting blade 60A and a rotary cutting blade 60B are provided on the other end side of the fixed stage 54. Thus, the molded body 48 set in the fixed stage 54 is cut into a lattice shape by the lattice-shaped cutting blade 60A while being pushed out at a predetermined speed by the transport mechanism 56, and is then approximately 3 mm square by the rotary cutting blade 60B. It is cut into cubes. The cut carrier 62 is further introduced into the blower drying unit 28 provided on the downstream side.

  FIG. 4 is an explanatory diagram illustrating in detail an example of the configuration of the blower drying unit 28 of FIG. 3.

  The blower drying unit 28 includes a pallet 64 that houses the carrier 62, and a blower unit 66 that is provided below the pallet 64 and supplies dry air from the bottom surface of the pallet 64.

  The pallet 64 has a plurality of holes 64 </ b> A for taking in dry air on the bottom surface. The pallet 64 is provided with a stirrer 68 so that the carrier in the pallet 64 can be stirred.

  In the pallet 64, a thermometer 70 (temperature measuring means) for measuring the surface temperature of the carrier 62 is provided. The air blowing means 66 is provided with a temperature controller 72 (temperature adjusting means) for adjusting to a constant air blowing temperature based on the measurement result of the thermometer 70. In addition, as shown in FIG. 4, you may also provide the thermometer 71 which measures ventilation temperature as needed.

  As a result, while sensing the surface temperature of the carrier 62 in the pallet 64, the carrier can be blown and dried so that the temperature of the carrier falls within a predetermined range (10 to 40 ° C.). If the air temperature and the surface temperature of the carrier are substantially the same, the same control may be performed while sensing the air temperature.

  In this way, the drying air set at a predetermined temperature is supplied from the blower 66 as an upward flow from the hole 64 </ b> A on the bottom surface of the pallet 64. Further, by supplying the drying air while stirring the carrier 62 with the stirrer 68, even when the amount of the carrier to be processed is increased, the dead space can be reduced and the air can be uniformly blown and dried.

  The carrier 62 reduced in volume as described above can be applied to, for example, a wastewater treatment apparatus 80 as shown in FIG. FIG. 5 is a schematic view showing an application example of a carrier reduced in volume by the method of the present invention. In the figure, an example is shown in which a carrier 62 in which nitrifying bacteria are immobilized is introduced into a biological treatment tank 82 (aeration tank) to perform a nitrification reaction.

  The biological treatment tank 82 is provided with an introduction pipe 84 for introducing raw water and a discharge pipe 86 for discharging the treated water, and a screen for suppressing the carrier 62 from flowing into the biological treatment tank 82. 88 and an air diffuser 90 for supplying air into the biological treatment tank 82 are provided.

  Thereby, the reduced carrier 62 returns to the shape before volume reduction in the biological treatment tank 82 and has nitrification activity equivalent to that before volume reduction. That is, since the carrier 62 is blown and dried at 10 to 40 ° C., the activity of microorganisms can be maintained at the same level before and after volume reduction, and in particular, the activity of nitrite oxidizing bacteria that are easily damaged by heat. It can suppress that it falls remarkably. Thereby, it can suppress that nitrite ion accumulate | stores in raw | natural water without being decomposed | disassembled.

  The configuration of the carrier manufacturing apparatus 20 (including the blower drying unit 28) is not limited to the above embodiment.

  As mentioned above, although preferable embodiment of the volume reduction method of the entrapping immobilization support based on this invention was described, this invention is not limited to the said embodiment, Various aspects can be taken.

  For example, in each of the above-described embodiments, an example in which the carrier reduced in volume by the method of the present invention is applied to the wastewater treatment step is not limited to this, but is introduced into an aquarium fish tank or a purification device thereof. It can also be applied to water purification.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. (1) Carrier surface temperature (blast temperature) and nitrification activity, (2) Carrier moisture content and nitrification activity, (3) Specific surface area and drying rate of carrier, (4) Molecular weight and drying rate of immobilization material, (5 The relationship between microbial concentration and nitrification activity, and (6) wastewater treatment performance of the present invention and conventional products were examined. The results are shown in FIGS.

In each example, a carrier having the carrier composition shown in Table 1 was used. Except for the study in (5), the concentration of microorganisms immobilized in the carrier was set to 10 ⁵ cells / ml or more for both ammonia-oxidizing bacteria and nitrite-oxidizing bacteria. The volume reduction of the carrier was performed by blowing and drying by the blowing and drying unit 28 of FIG.

(1) Surface temperature (air blowing temperature) of carrier and nitrification activity Using polyethylene glycol dimethacrylate as the main raw material, the carrier was molded into a 3 mm square shape. The blowing temperature was set so that the surface temperature of the carrier would be 5 to 45 ° C., dried for 24 hours, and the dried carrier was immersed in water for 24 hours to contain water. Then, using the water-containing carrier, NH ₄ —N ₄₀ mg / L raw water was continuously operated for 20 days under the condition of HRT 3 hours and carrier addition rate 10%, and nitrification activity was measured.

Nitrification activity, using the following equation, NO 3 _-N (nitrate nitrogen) in the treated water obtained from the nitrification rate by the amount.

Nitrification rate (%) = {(treated water NO ₃ −N) / (raw water NH ₄ −N)} × 100
The nitrification activity of each carrier was expressed as a relative value with the nitrification activity when the blowing temperature was set so that the surface temperature of the carrier 62 was 25 ° C. and dried by blowing. The result is shown in FIG.

When the blast temperature was set so that the surface temperature of the carrier was less than 10 ° C., ammonia remained in the treated water and the nitrification activity was low. On the other hand, when the blast temperature is set so that the surface temperature of the carrier becomes higher than 40 ° C., NO ₂ —N (nitrite nitrogen) remains in the treated water, and the reaction reaches NO ₃ —N (nitrate nitrogen). It did not progress and was found to have low nitrification activity.

  This is considered due to the following reasons. If the blast temperature is set so that the surface temperature of the carrier is less than 10 ° C., both the ammonia-oxidizing bacteria and nitrite-oxidizing bacteria are less active due to excessively low temperatures, and the ammonium ions in the raw water are less likely to decrease. On the other hand, when the blast temperature is set so that the surface temperature of the carrier exceeds 40 ° C., the activity of nitrite oxidizing bacteria that are particularly susceptible to damage due to heat is significantly reduced, and ammonium ions cannot be converted to nitrate ions. It is presumed that this is because it remains in this state. When this nitrite ion is accumulated in water, for example, when purifying the breeding water for aquarium fish, it is not preferable because it is highly toxic to the aquarium fish.

  Thus, it was found that the microorganisms in the carrier are easily affected by the blowing temperature, and it is necessary to set the blowing temperature so that the surface temperature of the carrier becomes 10 to 40 ° C.

(2) Moisture content of carrier and nitrification activity The carrier 62 formed into a 3 mm square was set at a blowing temperature so that the surface temperature of the carrier would be 25 ° C. and dried by blowing. At this time, different moisture content carriers were prepared by changing the drying time, and the moisture content of each carrier was measured. As described above, the moisture content was determined from the ratio of the weight of the carrier to this weight, assuming that the weight of the carrier when dried at 105 ° C. for 6 hours was 0%. Each carrier was immersed in water for 24 hours to contain water, and then NH ₄ —N ₄₀ mg / L raw water was continuously operated for 20 hours under conditions of HRT for 3 hours and a carrier addition rate of 10%, and the nitrification activity at that time was measured. did. The result is shown in FIG.

  The nitrification activity under each condition was shown as a relative value with the nitrification activity of a carrier having a moisture content of 5% after drying as 100. If the water content of the carrier is less than 1%, the nitrification activity rapidly decreases, and it is assumed that ammonia-oxidizing bacteria and nitrite-oxidizing bacteria (also referred to as nitrifying bacteria) were damaged during drying. On the other hand, when the moisture content of the carrier exceeded 5%, the surface of the carrier after drying became sticky and became lumps. Even when immersed in water, the lumps did not collapse and the nitrification activity decreased.

  Therefore, it turned out that the suitable moisture content after drying is 1 to 5%. Further, the carrier size at this time was about 1/10 before drying, and it was confirmed that the volume reduction effect was high.

(3) Specific surface area of carrier and drying speed In the present invention, the volume of the carrier is reduced by air drying, so that the drying speed varies depending on the specific surface area of the carrier. Therefore, the specific surface area of the carrier and the drying rate were examined.

  Carriers having different specific surface areas (carrier sizes) were prepared by changing the shape of the entrapping immobilization carrier when it contained water within a range of 0.5 to 8 mm square. And about each support | carrier, it set to the ventilation temperature from which the surface temperature of a support | carrier becomes 25 degreeC, and measured the moisture content when air-drying for 24 hours. The result is shown in FIG.

  The larger the specific surface area of the carrier, the easier it is to dry. On the other hand, since the drying speed is high, the shape of the carrier tends to collapse. It was also found that if the specific surface area is too small, it is difficult to dry because the contact area with the drying air is small, and the carrier surface tends to be sticky due to the unpolymerized material.

Therefore, it was found that the specific surface area of the entrapping immobilization support before drying (when containing water) is preferably 1200 to 6000 m ² / m ^{3 in order} to make the moisture content range (1 to 5%) described above. .

(4) Monomer molecular weight and water content of the immobilization material Encapsulated immobilization carriers having different molecular weights of polyethylene glycol dimethacrylate (immobilization material) were produced. Subsequently, about each support | carrier, the surface temperature of the support | carrier was set to the ventilation temperature which will be 25 degreeC, and the moisture content after carrying out ventilation drying for 24 hours was measured. The result is shown in FIG.

  It was found that the higher the molecular weight of the monomer, the higher the moisture content after drying, and the lower the monomer molecular weight, the lower the moisture content after drying. As a result, it was found that the higher the molecular weight, the harder it is to dry, and the lower, the easier it is to dry.

  Therefore, it was found that the molecular weight of the immobilization material is preferably set to 1000 to 10,000 in order to make the moisture content range (1 to 5%) described above.

(5) Microbial concentration in carrier and microbial activity The effect on nitrification activity was examined by changing the microbial concentration (ammonia oxidizing bacteria concentration) in the carrier. Carriers having different microbial concentrations were prepared, the air temperature was set so that the surface temperature of the carrier was 25 ° C., and air-dried for 24 hours, and then the carrier was immersed in water for 24 hours to contain water. Using this water-containing carrier, NH ₄ —N ₄₀ mg / L raw water was continuously operated for 20 hours under the conditions of HRT 3 hours and carrier addition rate 10%, and the nitrification activity at this time was measured. The result is shown in FIG.

The nitrification activity of the carrier under each condition was expressed as a relative value with respect to 100 when the microbial concentration was 10 ⁶ cells / ml. 10, the although the concentration of microorganisms in the carrier nitrification activity is less than ¹⁰ 5 cells / ml ^decreased, in 10 5 cells / ml or ^higher, equivalent nitrification activity in the case of 10 6 cells / ml Obtained.

Therefore, it was found that the microorganism concentration in the carrier is preferably 10 ⁵ cells / ml or more.

(6) Wastewater treatment performance of the present invention and conventional products A carrier (Example) blown and dried by the volume reduction method of the present invention, a carrier thermally dried by a conventional method (Comparative Example), and before conventional drying (when containing water) 3 types of carriers (reference example). The carrier of the example was blown and dried for 24 hours with the blowing temperature set so that the surface temperature of the carrier was 25 ° C. The carrier of the comparative example was thermally dried at 105 ° C. for 2 hours. In the examples and comparative examples, the moisture content after drying was set to 2%. And the daily change of the water quality was measured when the raw water of NH ₄ -N ₄₀ mg / L was aerated under the conditions of HRT for 3 hours at a carrier addition rate of 10% and continuously operated. The result is shown in FIG.

The carrier of the example to which the present invention was applied showed almost the same tendency as the conventional carrier when containing water (reference example), and it took 18 days until NH ₄ -N in the treated water became 1 mg / L or less. On the other hand, it was found that 15 mg / L of NH ₄ -N remained in the carrier of the comparative example that had been heat-dried even after 30 days. This is presumably because the carrier of the comparative example was inactivated due to damage caused by heat.

  From the above, it was confirmed that the carrier reduced by the volume reduction method of the present invention can maintain high activity without the microorganisms retained in the carrier being damaged by volume reduction.

It is a block diagram explaining the flow from the manufacturing process of the support | carrier to which this invention is applied to a biological treatment process. It is explanatory drawing explaining the manufacturing method of a comprehensive fixed support | carrier. It is a figure which shows schematic structure of the manufacturing apparatus of the support | carrier which concerns on this invention. It is explanatory drawing explaining the structure of the ventilation drying part of FIG. 3 in detail. It is a schematic diagram which shows the example of application of the support | carrier reduced by the method of this invention. It is a graph which shows the result in a present Example. It is a graph which shows the result in a present Example. It is a graph which shows the result in a present Example. It is a graph which shows the result in a present Example. It is a graph which shows the result in a present Example. It is a graph which shows the result in a present Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 12 ... Manufacturing process, 14 ... Volume reduction process, 16 ... Storage and conveyance process, 18 ... Returning process, 19 ... Biological treatment process, 20 ... Carrier manufacturing apparatus, 22 ... Raw material preparation part, 24 ... Molding part, 26 ... Cutting , 28 ... ventilation drying part, 62 ... carrier, 64 ... pallet, 66 ... air blowing means, 64 A ... hole, 68 ... stirrer, 70 ... thermometer, 72 ... temperature controller, 80 ... wastewater treatment device, 82 ... biological treatment Tank

Claims (9)

A method for reducing the volume of a entrapping immobilization support in which microorganisms are entrapped and immobilized inside an immobilization material,
Comprising the step of reducing the volume by blowing and drying so that the surface temperature of the entrapping immobilization support is 10 to 40 ° C. ,
A method for reducing the volume of a entrapping immobilization carrier, comprising drying by blowing until the moisture content of the entrapping immobilization carrier becomes 1 to 5% . The method for reducing the volume of a entrapping immobilization support according to claim 1 , wherein the entrapping immobilization support before blow-drying has a specific surface area of 1200 to 6000 m ² / m ³ . The immobilization material, with an acrylate or diacrylate derivative become more polymer with ethylene oxide and propylene oxide, to claim 1 or 2 molecular weight of the acrylate or diacrylate derivative, characterized in that 1,000 to 10,000 A method for reducing the volume of the entrapping immobilization support as described. The method for reducing the volume of a entrapping immobilization carrier according to any one of claims 1 to 3 , wherein the microorganism is contained in the entrapping immobilization carrier before the air drying by 10 ⁵ cells / mL or more. The method for reducing the volume of a entrapping immobilization carrier according to any one of claims 1 to 4, wherein the time for the blast drying is 12 hours to 24 hours.   A entrapping immobilization carrier in which microorganisms are entrapped and immobilized inside an immobilization material, wherein the volume is reduced by the entrapping immobilization carrier volume reduction method according to any one of claims 1 to 5. Comprehensive immobilization carrier.   A method for purifying water quality, wherein the entrapping immobilization carrier according to claim 6 is immersed in water and swollen, and then used for water purification. A device for producing a entrapping immobilization carrier in which microorganisms are entrapped and immobilized inside an immobilization material,
A preparation unit for preparing a mixture of the microorganism and the immobilization material;
A molding part to be molded by polymerizing the prepared mixture;
A cutting part to be a entrapping immobilization carrier by cutting the molded body into a predetermined size;
An air drying unit for air drying at a predetermined temperature with respect to the entrapping immobilization carrier;
An apparatus for producing a entrapping immobilization carrier, comprising: The blower drying unit
Measuring means for measuring the surface temperature of the entrapping immobilization support;
Temperature adjusting means for adjusting the blowing temperature based on the result of the measuring means;
The entrapping immobilization carrier manufacturing apparatus according to claim 8, comprising:

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