JP4470169B2 - Water treatment method and apparatus - Google Patents

Description

The present invention relates to a water treatment how and apparatus, a method and particularly acclimating the carrier thereby removing processes the harmful components in the for-treatment water biologically using a carrier particulate immobilized microorganisms Relates to the device.

  In order to address the problem of eutrophication in closed waters, it is highly desirable to remove nitrogen in the influent wastewater. Nitrogen is mainly contained in sewage and various industrial wastewater in the form of ammoniacal nitrogen. Biological methods are generally employed as methods for removing ammoniacal nitrogen from wastewater. This method uses nitrifying bacteria to oxidize ammonia nitrogen to nitrite and nitric acid, and then uses denitrifying bacteria to convert nitrous acid and nitric acid to nitrogen gas for removal.

Because nitrifying bacteria have a slow growth rate, in order to perform stable nitrogen removal, it is necessary to perform low-load operation in the nitrification reaction tank with a nitrogen load of 0.2 to 0.4 kg-nitrogen / m ³ / day. There is an increase in the size of the nitrification reaction tank. As a countermeasure against this, a method of keeping a high concentration of nitrifying bacteria by introducing a carrier on which nitrifying bacteria are immobilized into a nitrification reaction tank is becoming widespread. According to this method, high-speed processing in which the nitrification reaction tank is miniaturized becomes possible.

  In order to maintain not only nitrifying bacteria but also organic matter-degrading bacteria, environmental hormone-degrading bacteria, etc. at a high concentration and perform high-speed processing, a carrier on which these microorganisms are immobilized has been used or researched and developed ( For example, see Patent Document 1 and Patent Document 2).

By the way, in the water treatment facility using this type of carrier, when the new design picture of the facility is materialized and the harmful component to be removed becomes clear, the most suitable microorganism for removing the target harmful component is selected. And the support | carrier which fix | immobilized the said microorganism or the support | carrier for fix | immobilizing a microorganism is manufactured previously by a support | carrier manufacturing factory according to the construction process of a water treatment plant | facility. When the water treatment facility is completed, the manufactured carrier is put into the reaction tank, and after a trial run, the main operation is started.
Japanese Patent No. 3389811 Japanese Patent No. 3514360

  However, the carrier immediately after being produced at the carrier production plant usually has a low concentration of immobilized microorganisms and is poor in activity, and a long acclimatization period is required until the treatment is stabilized in actual operation. In particular, it may take several months for microorganisms to adhere sufficiently to the carrier in the case of an attachment type carrier in which microorganisms are gradually adhered in actual operation without fixing microorganisms at the carrier manufacturing factory stage. It was a serious factor that delayed the start of driving. Such a problem is relatively alleviated in the entrapping immobilization type carrier in which microorganisms are entrapped and immobilized in advance at the stage of the carrier production factory, but it still requires a acclimatization period of about one month. In addition to the case where a water treatment facility is newly established, there is a similar problem when a carrier is newly added to or replenished to an existing water treatment facility.

Object of the present invention to improve the problems of the prior art, while maintaining the water treatment function is to provide a water treatment how and apparatus capable of acclimatization a highly active carrier easily .

To achieve the above object, the water treatment how according to the present invention, the microorganism was supplied water to be treated into the reaction vessel containing the immobilized granular carrier, contacting said carrier with the water to be treated the harmful components of the treatment water to a water treatment method for removing treated biologically by a part of the carrier load of the harmful components were accommodated in the reaction vessel when it is less than the set value Repeating a carrier drawing process for drawing out for diversion to another water treatment facility, and a new carrier feeding process for feeding a granular new carrier into the reaction tank at a set timing after the carrier drawing process is completed. It is characterized by. In the present invention, the new carrier means a carrier that has been produced in a carrier production plant and has no microorganisms immobilized thereon, an unfamiliar carrier in which microorganisms are immobilized, or a carrier that has not been acclimatized. To do.

In the above method, the microorganism is a nitrifying bacterium, the harmful component is a nitrogen component, the set value is 30 to 50 mg-nitrogen / h / L-carrier, and the set timing is the value of the harmful component. It is desirable that the load be over 50 mg-nitrogen / h / L-carrier.
The microorganism is an anaerobic ammonia oxidizing bacterium, the harmful component is a nitrogen component, and the set value is preferably 80 mg-nitrogen / h / L-carrier .

The water treatment MakotoSo location according to the present invention, removed by treatment harmful components in the for-treatment water biologically by housing the particulate carrier obtained by immobilizing microorganisms contacting the water to be treated and the carrier A reaction tank, a carrier extraction means for extracting a part of the carrier from the reaction tank, a carrier storage means for storing the carrier extracted by the carrier extraction means, and a granular new support are introduced into the reaction tank. And a new carrier charging means. In this case, a monitoring means for monitoring the quality of the treated water flowing into the reaction tank and / or the treated water discharged from the reaction tank is provided, and the carrier pulling means is controlled based on the monitoring result by the monitoring means. It is desirable to have done.

  The present invention includes a carrier extracting step of extracting a part of the carrier in the reaction vessel from the reaction vessel by the carrier extracting means. The extracted carrier is acclimatized in the reaction tank and has high activity. For this reason, the extracted carrier can be diverted to other water treatment facilities that require the same carrier. In the case where another water treatment facility as a diversion destination is newly established, the use period of the carrier can be greatly shortened by using this highly active carrier, and the shift to actual operation can be accelerated. In the carrier extraction process, only a part of the carrier contained in the reaction tank is extracted, so that in the reaction tank, the remaining highly active carrier comes into contact with the water to be treated and biologically removes harmful components in the water to be treated. Maintained.

  In addition, the present invention includes a new carrier charging step of charging a granular new carrier into the reaction tank by a new carrier charging means. The introduced new carrier is mixed with the highly active carrier remaining in the reaction tank, and gradually becomes acclimatized and becomes a carrier in which microorganisms are immobilized at a high concentration. Water treatment that removes harmful components from the water to be treated by repeating the carrier drawing process and the new carrier loading process by making the amount of the carrier drawn in the carrier drawing process the same as the new carrier charged in the new carrier loading process. It is possible to realize a method and an apparatus having both a function and a carrier acclimatization function for acclimatizing and supplying a highly active carrier for diversion to other water treatment facilities.

  The throughput of the reaction vessel is temporarily reduced by withdrawing the carrier. For this reason, it is desirable to carry out the carrier drawing process when the load of harmful components is low and the processing capacity of the reaction tank is sufficient. Therefore, if the carrier is pulled out when the load of harmful components is below the set value, water treatment can be performed while maintaining the removal performance of the harmful components. In addition, if aeration is continued when the load of harmful components is low in the reaction tank, there is a phenomenon in which an aeration state occurs, microorganisms immobilized on the carrier are self-degraded, and the activity of the carrier is reduced. Therefore, if the carrier is withdrawn when the load of harmful components is below the set value, the carrier will be withdrawn before the activity declines, so acclimatize a highly active carrier for diversion to other water treatment facilities. Can be supplied. Furthermore, when the carrier is pulled out, the load of harmful components of the carrier remaining in the reaction tank increases, and the air aeration state is eliminated. Therefore, it is possible to suppress a decrease in the activity of the carrier at a low load. Note that it is not necessary to shift to the new carrier charging step immediately after the carrier drawing step, and it is preferable to load the new carrier when the load is recovered.

  In addition, when a monitoring means for monitoring the quality of the treated water flowing into the reaction tank and / or the treated water discharged from the reaction tank is provided, and the carrier extraction means is controlled based on the monitoring result, automatic control at a suitable timing is possible. And the reliability of the method and apparatus according to the present invention can be increased.

When a entrapping immobilization type carrier is used as the carrier according to the present invention, it is obtained by mixing a monomer material or prepolymer material and a microorganism and polymerizing the mixture. As the monomer material, acrylamide, methylenebisacrylamide, triacryl formal and the like are preferable. The prepolymer material is preferably polyethylene glycol diacrylate or polyethylene glycol methacrylate, and derivatives thereof can also be used. The carrier is formed into a spherical shape, a square shape or a cylindrical shape, and the size is preferably 1 to 10 mm as a sphere equivalent diameter. For example, in the case of nitrifying bacteria, the concentration of microorganisms to be immobilized exhibits activity when the number of nitrifying bacteria is 10 ⁶ / mL-carrier or more. When the number of nitrifying bacteria at the time of acclimatization is 10 ⁵ / mL-carrier or more, it grows to 10 ⁸ / ml-carrier or more inside the carrier by appropriate acclimatization.

  In addition, when an adhesion-type carrier is used as the carrier according to the present invention, a spherical, square, or cylindrical shape such as polyethylene or polypropylene, or a foam or net-like shape is preferable. The size is preferably a sphere equivalent diameter of 1 to 10 mm. A granular adhering carrier having a particle size of less than 1 mm can also be used.

  Microorganisms to be immobilized are activated sludge, nitrifying bacteria group, denitrifying bacteria group, anaerobic ammonia oxidizing bacteria group and other complex microorganisms, or nitrifying bacteria, denitrifying bacteria, anaerobic ammonia oxidizing bacteria, blue-green-decomposing bacteria, PCB-degrading bacteria, There are pure bacteria such as dioxin degrading bacteria and environmental hormone degrading bacteria.

The basic experiment results using the carrier will be described below. Nitrifying bacteria were used as microorganisms to be immobilized. That is, persulfuric acid as a polymerization agent in a suspension obtained by mixing 30 parts of a nitrifying bacteria concentrate (10 ⁹ bacteria / mL), 10 parts of polyethylene glycol diacrylate, 0.5 part of tetramethylethylenediamine, and 59.25 parts of water. When 0.25 part of potassium is added, polymerization starts and gelation occurs. This gel was cut into a cube having a side of 3 mm, and used as a comprehensive support for basic experiments.

Experiment 1 (Air aeration experiment)
By acclimation, a carrier in which nitrifying bacteria were sufficiently grown (number of nitrifying bacteria: 10 ⁸ / mL-carrier) was prepared. This carrier was aerated in fresh water without nutrients, and the change in the number of nitrifying bacteria was examined. For comparison, the case where the carrier was drained and stored at a predetermined temperature was also examined. FIG. 5 shows the experimental results. In FIG. 5, line C shows the case where air aeration is performed, line D shows the case where it is stored at 20 ° C., and line E shows the case where it is stored at 5 ° C. Air aeration reduces the number of nitrifying bacteria in the carrier with a half-life of 4 days. This is because nitrifying bacteria self-decomposed by air aeration. On the other hand, when stored without aeration, there is little decrease in the number of bacteria, especially when stored at 5 ° C., the number of bacteria hardly decreases.

Experiment 2 (Experiment for bacterial growth inside the carrier)
Acclimated carrier (nitrifying bacteria number 10 ⁵ / mL-support) immediately was added to raw water of ammonium nitrogen concentration 100 to 400 mg / L, varying the nitrogen component load 10~313mg-N / h / L- carrier The growth status of nitrifying bacteria after 1 month of culture in each load was examined. FIG. 6 shows the experimental results. When the nitrogen component load is as low as 10 or 21 mg-N / h / L-carrier, the number of nitrifying bacteria hardly grows. In order to increase the number of nitrifying bacteria exhibiting activity as 10 ⁶ carriers / mL-carrier or more, the nitrogen component load is 33 mg-N / h / L-carrier or more, preferably about 50 mg-N / h / L-carrier. It turns out that it should be retained.

  FIG. 1 is an apparatus system diagram showing a first embodiment of the present invention. The reaction tank 10 has an inlet for treated water 12 and an outlet 15 for treated water 14. In addition, a granular carrier 16 on which microorganisms are immobilized is placed in the reaction tank 10. The total amount of the carrier 16 is about 10 to 30% of the effective volume of the reaction tank 10. When the immobilized microorganisms are aerobic microorganisms such as nitrifying bacteria, air is sent from the blower 20 to the air diffuser 18 disposed at the bottom of the reaction tank 10 to aerate the inside of the reaction tank 10. Due to this aeration energy, the water to be treated 12 into which the carrier 16 has flowed in and the carrier 16 are mixed and contacted. As a result, harmful components to be removed in the treated water 12 come into contact with microorganisms immobilized on the carrier 16, and the harmful components are decomposed or oxidized and removed by biological action of the microorganisms. When the immobilized microorganism is an anaerobic microorganism such as a denitrifying bacterium, the carrier 16 is caused to flow by using a stirrer instead of the aeration means 18 or blowing an inert gas into the reaction tank 10. .

  A screen 22 is provided on the outlet 15 side of the reaction tank 10, and the carrier 16 and the treated water 14 are separated by this screen 22. A carrier extraction pipe 24 having a pump 25 is connected to the reaction tank 10, and the other end of the carrier extraction pipe 24 is connected to a carrier storage tank 26. It is desirable to place the carrier storage tank 26 in a refrigeration facility and place it in an environment of about 5 ° C. The water to be treated and the carrier 16 drawn out from the reaction tank 10 by the pump 25 are sent to the upper part of the carrier storage tank 26, and the carrier 16 is stored by sinking downward. The water to be treated separated from the carrier 16 is returned to the reaction tank 10 through the overflow tank 28. A carrier return pipe 32 having an on-off valve 30 is connected to the bottom of the carrier storage tank 26, and the other end of the carrier return pipe 32 is connected to the reaction vessel 10. A carrier discharge pipe 34 is branched from the carrier return pipe 32 via an on-off valve 36.

  In addition, a new carrier charging tank 38 is attached to the reaction tank 10. The new carrier charging tank 38 is filled with, for example, an unfamiliar new carrier 16A manufactured at a carrier manufacturing factory. A new carrier input pipe 42 having an automatic opening / closing valve 40 is connected to the bottom of the new carrier input tank 38, and the other end of the new carrier input pipe 42 is connected to the reaction tank 10. Therefore, by opening the automatic opening / closing valve 40, the new carrier 16A in the new carrier charging tank 38 is replenished into the reaction tank 10.

  A detector 46 that detects the concentration of harmful components in the water to be treated is disposed in the inflow pipe 44 of the water to be treated. The detection value of the detector 46 is transmitted to the controller 48, and the controller 48 calculates the load of harmful components in the reaction tank 10 based on the detected value of the harmful component concentration in the treated water transmitted from the detector 46. . Further, when the amount of the carrier charged in the reaction tank 10 is known, the load of harmful components on the carrier is also calculated. Then, the controller 48 controls the driving of the pump 25 as the carrier drawing means and the opening and closing of the automatic opening / closing valve 40 as the new carrier loading means according to the calculated loads of these harmful components.

  In the apparatus having the above-described configuration, when the water to be treated is, for example, sewage in daily life, the water quality varies from year to year, period, week, and day, and the load of harmful components for the purpose of removal varies greatly due to the variation in water quality. FIG. 2 is an explanatory diagram exemplifying the fluctuation state of the load of harmful components. In the figure, the load F1 is the planned load of the water treatment facility, and is set to a value close to the maximum expected load. The capacity of the reaction tank 10 and the input amount of the carrier 16 are determined according to this planned load. ing. The load F2 is a quarter of the planned load F1. As shown in the figure, the load of harmful components generally fluctuates greatly, and the time zone exceeding the planned load is very temporary, and in most time zones, the operation is less than the planned load. In many cases, the time zone S of the low load operation below the load F2 also occupies a considerable proportion. In such a low load operation time zone S, the carrier 16 is placed in an excessive amount. For microorganisms immobilized on the carrier 16, a low load of harmful components means a lack of nutrition, and the microorganisms are placed under the same conditions as air aeration. For this reason, as apparent from Experiment 1 described above, the microorganisms are autodegraded and the activity of the carrier 16 is reduced.

  In the present embodiment, the apparatus is operated based on the technical background described above. That is, when the load of harmful components becomes a set value (for example, load F2) or less, the controller 48 temporarily drives the pump 25 to remove a part of the carrier 16 put in the reaction tank 10 from the reaction tank 10. The extracted carrier 16 is fed into the carrier storage tank 26. In the carrier storage tank 26, the fed carrier 16 is temporarily stored. The withdrawal amount of the carrier 16 for one time is about 3 to 5% of the total amount. If the load of harmful components continues to be below the set value even after one extraction of the carrier 16, the same extraction operation is repeated. Since the capacity of the carrier storage tank 26 is limited, it is preferable to limit the maximum amount of the carrier 16 temporarily stored in the carrier storage tank 26 to, for example, about 20 to 30% of the total carrier amount.

  Since the extracted carrier 16 is a carrier immediately after the load of harmful components reaches a set value, it is not subjected to autolysis and maintains high activity. The carrier 16 stored in the carrier storage tank 26 is extracted from the carrier discharge pipe 34 at an appropriate timing and shipped, or temporarily stored in a shipping refrigeration facility 50 whose environment is maintained at about 5 ° C. The high-activity carrier 16 to be shipped can be diverted to other water treatment facilities that require a similar carrier, for example. When another water treatment facility which is a diversion destination is newly established, the use period of the carrier can be greatly shortened by using the highly active carrier 16, and the shift to actual operation can be accelerated.

  On the other hand, in the reaction tank 10, the absolute amount of the carrier 16 accommodated therein is reduced by pulling out the carrier 16. For this reason, the load of the harmful component with respect to the support | carrier 16 becomes high correspondingly, a low load state is recovered | restored, and the active fall of the support | carrier 16 is suppressed. As a result, since the carrier 16 in the reaction tank 10 maintains high activity, stable treatment is continued, and even when the load is shifted to a high load due to fluctuations in the quality of the water to be treated. That is, the apparatus according to the present embodiment functions as a water treatment apparatus that removes harmful components in the water to be treated, and a carrier habitation apparatus that accompanies and supplies a highly active carrier for diversion to other water treatment facilities. Combined with the functions.

  When the drawing operation of the carrier 16 is completed, the reaction tank 10 is replenished with a new carrier 16A in an amount suitable for the drawn carrier 16. That is, the controller 48 opens the automatic opening / closing valve 40 as soon as possible after the operation of pulling out the carrier 16 is completed, and replenishes the reaction vessel 10 with the new carrier 16A in the new carrier charging tank 38. The new carrier 16A is a carrier having a low activity immediately after being manufactured at a carrier manufacturing plant, for example. The new carrier 16A does not exhibit a great ability to remove harmful components immediately after being introduced into the reaction tank 10, but gradually becomes acclimatized and becomes active. After a few weeks, it becomes a highly active carrier 16.

  When the load of harmful components is equal to or higher than the set value, the current operation is continued without removing the carrier 16 as a general rule, focusing exclusively on ensuring the performance as a water treatment device and accustoming the replenished new carrier 16A. . When the shipping destination of the carrier 16 stored in the carrier storage tank 26 is not found for the time being and the storage period of the carrier 16 in the carrier storage tank 26 is long, the carrier 16 is stored from the carrier return pipe 32 at the bottom of the carrier storage tank 26. The carrier 16 is returned to the reaction vessel 10. Then, again, the carrier 16 extracted from the reaction tank 10 and stored in the carrier storage tank 26 is updated. In addition, when the load of harmful components in the reaction tank 10 increases rapidly and the treatment is insufficient in the current operation, it is similarly stored from the carrier return pipe 32 at the bottom of the carrier storage tank 26 as a temporary measure. The carrier 16 can be returned to the reaction tank 10.

  According to the first embodiment, when the load of harmful components is below the set value, a part of the carrier 16 is pulled out from the reaction tank 10 and stored in the carrier storage tank 26. For this reason, in the reaction tank 10, the load of harmful components per unit volume of the carrier is increased by that amount, and the state of air aeration can be avoided, and the decrease in the activity of the carrier 16 in the reaction tank 10 can be prevented. Moreover, in the reaction tank 10, the load of harmful components per unit volume of the carrier is always maintained in an appropriate range, and stable biological treatment can be continued. Further, the carrier 16 stored in the carrier storage tank 26 is highly active, and this carrier 16 can be shipped and diverted to other water treatment facilities that require the same carrier. When another water treatment facility which is a diversion destination is newly established, the use period of the carrier can be greatly shortened by using the highly active carrier 16, and the shift to actual operation can be accelerated. Further, when the other existing water treatment facility requires a highly active carrier for reasons such as malfunction, the extracted carrier 16 can be diverted. Therefore, the apparatus according to the present embodiment is a water treatment apparatus that stably removes harmful components in the water to be treated, or a carrier habitation apparatus that accompanies and supplies a highly active carrier for diversion to other water treatment facilities. Is also useful.

When the harmful component is ammoniacal nitrogen, it is desirable to set the set value of the nitrogen component load to 30 to 50 mg-nitrogen / h / L-carrier or more. That is, as shown in FIG. 6, in the vicinity of the nitrogen component load of 30 to 50 mg-nitrogen / h / L-carrier, the carrier 16 has a number of nitrifying bacteria of about 10 ⁶ to 10 ⁷ cells / mL-carrier, There is enough activity. By pulling out the carrier 16 and shipping it, the shipping destination can exhibit its activity immediately.

  FIG. 3 is an apparatus system diagram showing a second embodiment of the present invention. In FIG. 3, elements denoted by the same reference numerals as those in FIG. 1 are the same elements as in FIG. In this 2nd Embodiment, the water quality meter 52 which monitors the quality of the treated water is arrange | positioned at the discharge port 15 of the treated water, and the detected value of the water quality meter 52 is transmitted to the controller 48A. In the controller 48A, based on the detected value of the harmful component concentration in the for-treatment water transmitted from the detector 46 and the detected value of the treated water transmitted from the water quality meter 52, driving of the pump 25 which is a carrier drawing means, The automatic opening / closing valve 40 and the automatic opening / closing valve 30 </ b> A provided in the carrier return pipe 32 are controlled to open and close as new carrier loading means.

  FIG. 4 is a flowchart showing an example of control in this embodiment. First, in step S100, the detection value of the water quality meter 52 is transmitted to the controller 48A. If the water quality of the treated water is appropriate (the drainage standard value or less), the process proceeds to the next step S110. Further, if the quality of the treated water is inappropriate (over the drainage standard value), it is determined that the amount of carrier in the reaction tank 10 is insufficient, and the controller 38A opens the automatic opening / closing valve 30 to the carrier storage tank 26. Control is performed so that at least a part of the stored drawing carrier is returned to the reaction vessel 10 (S120). In step S110, based on the detected value of the harmful component concentration in the water to be treated transmitted from the detector 46, the load of the harmful component on the carrier in the reaction tank 10 is calculated. If the calculated load of harmful components is equal to or less than the set value in the controller 48A, the pump 25 is driven with a count N = 0, and the carrier 16 accommodated in the reaction tank 10 (4% of the total carrier amount) Is extracted from the reaction tank 10, and the extracted carrier 16 is fed into the carrier storage tank 26 (S130). Next, in step S140, if the calculated load of harmful components is equal to or less than the set value, the count is set to N = N + 1, and the carrier 16 (4% of the total amount) is again withdrawn from the reaction tank 10, and the same applies to the harmful components. If the load is less than the set value, the extraction of the carrier is repeated until the count reaches N = 5. As a result, a maximum amount of the carrier 16 corresponding to 20% of the total carrier amount is pulled out and stored in the carrier storage tank 26.

  If the load of harmful components exceeds the set value in step S140, the controller 48A opens the automatic opening / closing valve 40 and reacts by an amount corresponding to the carrier 16 from which the new carrier 16A stored in the new carrier charging tank 38 has been withdrawn. It controls so that it may throw into the tank 10 (S150).

  If the load of harmful components exceeds the set value in step S110, the current operation is continued. Thereafter, the same control is repeated at a frequency of once every several hours in the same procedure. If the quality of the treated water flowing in is severe, calculating the load of harmful components based on the detection value of the detector 46 at each time point causes the calculated value to fluctuate with the quality of the treated water. Become stable. Therefore, when calculating the load of harmful components, it is desirable to use a value obtained by averaging the detection value of the detector 46 in a predetermined time zone (for example, control interval time).

  According to the second embodiment, the water quality of the treated water 14 is monitored, and if the water quality is inappropriate (over the drainage standard value), the extracted carrier is returned to the reaction tank 10. The water quality can be stabilized.

  The present invention is not limited to the first embodiment or the second embodiment. For example, it is possible to omit the water quality monitoring of the treated water 12 and the treated water 14 and the automatic control system of the controllers 48 and 48A. That is, the present invention also includes a configuration in which the operator manually operates the carrier extraction means and the new carrier input means based on the result of the water quality inspection by periodic sampling of the treated water 12 and the treated water 14.

  Further, as the carrier extracting means, an air lift type pump may be employed instead of the spiral type pump 25 shown in FIGS. The new carrier charging means may employ various pumps in place of the automatic opening / closing valve 40 shown in FIGS.

  The new carrier according to the present invention is not limited to the carrier immediately after being produced at the carrier production plant, and may be any carrier as long as the activity needs to be increased by habituation because the activity is relatively low.

Example 1
As a polymerization agent, a suspension obtained by mixing 50 parts of a nitrifying bacteria concentrate (10 ⁵ bacteria / mL), 4 parts of polyethylene glycol diacrylate, 1 part of acrylamide, 0.5 part of tetramethylethylenediamine, and 44.25 parts of water. When 0.25 part of potassium persulfate is added, polymerization starts and gelation occurs. This gel was cut into a cube having a side of 3 mm, and used as an experimental carrier. The experimental conditions are as follows.
Experimental apparatus Water to be treated as shown in FIG. 1 BOD about 10 mg / L, ammoniacal nitrogen 128-168 mg / L
Retention time of water to be treated in reaction tank 8 hours Carrier filling rate in reaction tank 20%
Nitrogen loading on carrier 80-105 mg-nitrogen / h / L-carrier
(Plan load 110mg-nitrogen / h / L-carrier)

  Continuous treatment was performed using a carrier well conditioned under the above conditions. Since the water quality fluctuation of the treated water is small and the fluctuation of nitrogen load is also small, after 5% of the carrier is drawn out from the total amount as needed, an unfamiliar new carrier in an amount suitable for the drawn carrier is put into the reaction tank. The operation was repeated every 3 days. The carrier thus extracted is a carrier with high nitrification activity having the capacity of about 100 mg-nitrogen / h / L-carrier. When this carrier was treated under almost the same conditions as described above, stable treatment could be achieved without habituation. Moreover, the ammoniacal nitrogen of the treated water during the operation period was stable at 4 to 8 mg / L. In addition, when the carrier is withdrawn 25% with respect to the total amount of carrier at a time and a new carrier of the same amount is introduced, the load on the carrier immediately after withdrawal becomes large. It took 2 weeks to deteriorate to L and return to a stable treatment of 4 to 8 mg / L.

  As a comparative example, continuous treatment was performed under the same conditions using an unfamiliar new carrier immediately after production at the carrier production plant. The ammoniacal nitrogen of the treated water at the beginning of operation was 120 mg / L. Even after 3 weeks from the start of operation, the ammoniacal nitrogen of the treated water was as bad as 30 mg / L, and a 4-week acclimatization period was required to obtain a stable treatment result of 4 to 8 mg / L.

Example 2
The same carrier used in Example 1 was used as an experimental carrier. The experimental conditions are as follows.
Experimental apparatus Water to be treated as shown in FIG. 1 BOD about 10 mg / L, ammoniacal nitrogen 32 to 280 mg / L
Retention time of water to be treated in reaction tank 8 hours Carrier filling rate in reaction tank 20%
Nitrogen loading on carrier 20-175 mg-nitrogen / h / L-carrier Continuous treatment was carried out using a carrier well conditioned under the conditions described above. The quality of the water to be treated was large, and initially the nitrogen load was operating at a level of about 120 mg-nitrogen / h / L-carrier, but thereafter the nitrogen load rapidly decreased. Therefore, when the nitrogen load is reduced to 30 mg-nitrogen / h / L-carrier, the carrier pulling is started, and when the carrier drawing amount reaches 25% of the total amount, the carrier drawing is stopped, Stored at room temperature. Immediately after the extraction of the carrier, the new carrier was not charged, and when the nitrogen load exceeded 50 mg-nitrogen / h / L-carrier, an unfamiliar new carrier in an amount suitable for the drawn carrier was charged into the reaction vessel. . By carrying out such an operation, it was possible to recover a carrier having an average nitrification activity of 45 mg-nitrogen / h / L-carrier. In addition, the ammoniacal nitrogen of the treated water during this period was stable at 4 to 8 mg / L.

Example 3
As an adhesive carrier, foamed polyethylene was cut into cubes having a side of 3 mm, and used as an experimental carrier.
Experimental apparatus Water to be treated as shown in FIG. 3 BOD about 10 mg / L, ammoniacal nitrogen 124-280 mg / L
Retention time of water to be treated in reaction tank 8 hours Carrier filling rate in reaction tank 20%
Nitrogen loading on carrier 78-175 mg-nitrogen / h / L-carrier
(Plan load 140mg-nitrogen / h / L-carrier)
Continuous treatment was carried out using a carrier to which nitrifying bacteria were sufficiently adhered by acclimation under the conditions described above. The control was performed according to the procedure shown in FIG. At this time, the judgment standard of ammonia nitrogen in the treated water was 5 mg / L, and the set value of nitrogen load on the carrier was 80 mg-nitrogen / h / L-carrier. As a result, it was possible to recover a carrier having an average nitrification activity of 80 mg-nitrogen / h / L-carrier while maintaining the ammoniacal nitrogen of the treated water at about 5 mg / L.

Example 4
Anaerobic ammonium oxidizing bacteria concentrate (a few 10 ⁹ bacteria / mL) 34 parts, 6 parts of polyethylene glycol diacrylate, 0.5 parts of tetramethylethylenediamine as a polymerization agent mixture suspension water 59.25 parts over When 0.25 part of potassium sulfate is added, polymerization starts and gelation occurs. This gel was cut into a cube having a side of 3 mm, and used as an experimental carrier. The experimental conditions are as follows.
Experimental apparatus Similar to that shown in FIG. However, by stirring the inside of the reaction tank without performing aeration by aeration means, the inside of the tank is maintained under anaerobic conditions. To-be-treated water Ammonia nitrogen 300 mg / L, nitrite nitrogen 360 mg / L
Residence time of water to be treated in reaction tank 4 hours Carrier filling rate in reaction tank 15%
Continuous treatment was performed using a carrier well conditioned under the above conditions. The control was performed by simplifying the procedure shown in FIG. That is, the judgment standard of the total nitrogen concentration of treated water was 80 mg / L, and the extraction of the carrier was started at 80 mg / L or less. The drawing was stopped when the carrier was drawn 25% with respect to the total amount of the carrier, and the drawn carrier was stored at room temperature. In addition, an unfamiliar new carrier in an amount suitable for the drawn carrier was charged into the reaction vessel at an appropriate timing. In this manner, as a result of the operation to repeat the introduction of pulling the new carrier of the carrier, while maintaining a total nitrogen concentration in the treated water below approximately 80 mg / L, the number of bacteria in the anaerobic ammonium oxidizing bacteria 10 ⁷ A high activity carrier of -10 ⁸ cells / mL could be recovered.

1 is an apparatus system diagram showing a first embodiment of the present invention. It is explanatory drawing which modeled and illustrated the fluctuation condition of load. It is an apparatus system diagram which shows 2nd Embodiment of this invention. It is a flowchart which shows the example of control in 2nd Embodiment. 10 is a graph showing an experimental result of Experiment 2. 10 is a graph showing an experimental result of Experiment 3.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ......... Reaction tank, 12 ......... Water to be treated, 14 ......... Treatment water, 16 ...... Carrier, 18 ......... Air diffuser, 20 ...... Blower, 22 ...... Screen, 24 ... …… Carrier extraction pipe, 25 ... …… Pump, 26 ......... Carrier storage tank, 28 ......... Overflow tank, 30 ......... Open / close valve, 32 ......... Carrier return pipe, 34 ......... Carrier discharge pipe 36 ......... Open / close valve, 38 ......... New carrier input tank, 40 ......... Automatic open / close valve, 42 ......... New carrier input pipe, 44 ......... Inflow pipe, 46 ......... Detector, 48, ... 48A ... Controller, 50 ... Refrigeration equipment for shipping, 52 ... Water quality meter.

Claims (5)

Water to be treated is supplied to a reaction tank containing a granular carrier in which microorganisms are immobilized, and the carrier and the water to be treated are brought into contact with each other to remove harmful components in the water to be treated by biological treatment. A water treatment method, in which when a load of the harmful component is equal to or less than a set value, a carrier extraction step of extracting a part of the carrier accommodated in the reaction tank for diversion to another water treatment facility, and the carrier water treatment how to and repeating the new carrier adding step of drawing process turns on the new carrier particulate at a set timing after terminating the reaction vessel. The microorganism is a nitrifying bacterium, the harmful component is a nitrogen component, the set value is 30-50 mg-nitrogen / h / L-carrier, and the load of the harmful component is 50 mg-nitrogen at the set timing. The water treatment method according to claim 1, wherein the timing exceeds / h / L-carrier. The water treatment method according to claim 1, wherein the microorganism is an anaerobic ammonia oxidizing bacterium, the harmful component is a nitrogen component, and the set value is 80 mg-nitrogen / h / L-carrier. A reaction vessel that contains a granular carrier in which microorganisms are immobilized and contacts the treated water and the carrier to biologically treat and remove harmful components in the treated water, and one of the carriers from the reaction vessel. And a carrier storage means for storing the carrier extracted by the carrier extraction means, and a new carrier introduction means for introducing a granular new carrier into the reaction vessel. Mizusho MakotoSo location. A monitoring means for monitoring the quality of the treated water flowing into the reaction tank and / or the quality of the treated water discharged from the reaction tank, and the carrier extraction means is controlled based on the monitoring result by the monitoring means. water treatment MakotoSo location according to claim 4, characterized.

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