JP2006297374A - Method and apparatus for wastewater treatment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for wastewater treatment which is energy-saving, small-sized and capable of enhancing the efficiency for treating nitrogen wastewater containing hydrogen peroxide as well as reducing the running cost. <P>SOLUTION: The wastewater treatment apparatus for treating the nitrogen wastewater containing hydrogen peroxide comprises a regulation tank 1, a denitrification tank 3, and a nitrification tank 11 having an immersed membrane 16 for a microorganism treatment, followed by a photocatalyst tank 18 for a photocatalyst treatment. The photocatalyst treatment enables an advanced treatment of the nitrogen wastewater containing hydrogen peroxide exceeding the limit of the water quality via the microorganism treatment. Therefore, the wastewater treatment apparatus can enhance the efficiency for treating the nitrogen wastewater containing hydrogen peroxide and realize an apparatus which is more energy-saving, small-sized and can reduce more running cost than a conventional one. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wastewater treatment apparatus and a wastewater treatment method. As an example, the present invention relates to a wastewater treatment apparatus and a wastewater treatment method for complying with the restriction on the total amount of nitrogen by partial revision of the Water Pollution Control Law, which was enforced from April 2004. The present invention is, for example, a high-level nitrogen wastewater containing hydrogen peroxide mainly drained from a semiconductor factory (for example, a high-concentration ammonia-containing wastewater containing hydrogen peroxide) or an advanced treatment of nitrogen in aminoethanol-containing wastewater. The present invention relates to a wastewater treatment apparatus and a wastewater treatment method.

  Conventionally, high-concentration nitrogen wastewater, and as a specific example, high-concentration nitrogen wastewater such as high-concentration ammonia-containing wastewater having a concentration of about 3000 ppm has generally been biotoxic and therefore generally cannot be treated with microorganisms.

  In cases where the nitrogen-containing wastewater has been microbially treated, treatment with a low ammonia concentration of several hundred ppm has been common.

  Therefore, wastewater containing high-concentration ammonia of 3000 ppm or more was concentrated to about 1/10 using an evaporator as a physical method, and the concentrated liquid was disposed as industrial waste. In the method of concentrating with this evaporator and discharging from the factory as industrial waste, the concentrate corresponds to industrial waste. As a result, industrial waste from business establishments is increased, and the disposal method of concentrated liquid as industrial waste is generally incineration, which causes problems such as air pollution due to the use of fuel such as heavy oil. there were. Further, the method of treating with an evaporator has a problem that the initial cost, running cost, and maintenance cost are high because a large amount of energy is consumed and the plant equipment becomes large.

  As another conventional technique, a biological treatment method is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2000-308900). According to this biological treatment method of the prior art, a stable treatment can be performed by preventing a reduction in treatment efficiency due to nitrite nitrogen generated when treating wastewater containing ammonia nitrogen at a high concentration. Specifically, in this biological treatment method, nitrite nitrogen is reduced to nitrogen gas by a biological denitrification method using autotrophic bacteria resistant to nitrite nitrogen and removed from waste water.

  In this ammonia-containing wastewater treatment method, treatment in a nitrification tank, a denitrification tank, an ultraviolet oxidation tank, a nitrification tank, a photocatalytic ultraviolet oxidation tank, a denitrification tank, and an ultraviolet oxidation tank is disclosed.

  As another prior art, another biological treatment method is described in Patent Document 2 (Japanese Patent No. 3467671).

  In this biological treatment method, the organic wastewater in the raw water tank is sequentially fed to the denitrification tank and the nitrification tank by a liquid feed pump and circulated between both tanks, so that ammonia nitrogen contained in the organic wastewater is circulated. Nitrogen gas is removed by reducing it to nitrogen gas using biological nitrification and denitrification, and using a suction pump, the sludge and treated water are separated by a filtration membrane unit immersed in the waste water in the nitrification tank. Denitrification method.

  As a feature of this nitrification / denitrification method, the pipe that feeds from the denitrification tank to the nitrification tank is branched in the middle, the tip of the branch is opened in the denitrification tank, and a part of the organic wastewater sent from the denitrification tank to the nitrification tank is It is blown out into the organic waste water in the denitrification tank. That is, in this nitrification / denitrification method, the waste water is sequentially fed to the denitrification tank and the nitrification tank by a liquid feed pump and circulated between both tanks.

  As another conventional technique, another biological treatment method is described in Patent Document 3 (Japanese Patent No. 3095620).

  In this biological treatment method, a denitrification tank into which raw water containing organic substances flows, a nitrification tank into which a denitrification tank mixed solution of this denitrification tank flows, and a nitrification liquid circulation channel for circulating the nitrification liquid in this nitrification tank to the above denitrification tank And a biological nitrogen removing apparatus including the nitrification tank diffuser disposed in the nitrification tank.

  More specifically, in this biological nitrogen removing apparatus, a denitrifying bacterium immobilization support filling zone for capturing and removing suspended substances in raw water flowing into the denitrifying tank is provided in the denitrifying tank. In addition, the raw water introduction channel and the nitrification solution circulation channel are communicated with the lower position of the denitrifying bacteria immobilization support filling zone of the denitrification tank, and the suspended matter trapped and removed in the denitrification bacteria immobilization support filling zone at the bottom of the denitrification tank. A sludge hopper for depositing is provided, and a hopper air diffuser is provided in the sludge hopper.

However, as described above, conventionally, wastewater containing high-concentration ammonia of about 3000 ppm has a high biological toxicity, and thus has not been generally treated with microorganisms. That is, because of high biological toxicity, high-concentration ammonia wastewater that cannot be treated with microorganisms has been treated by a concentration method or a vaporization separation method. For this reason, the concentration method has a problem of a large amount of energy consumption and an increase in industrial waste due to the concentrated solution. In addition to the large amount of energy consumption, the vapor separation method cannot treat nitrous acid or nitric acid other than ammonia. There are also drawbacks.
JP 2000-308900 A Japanese Patent No. 3467671 Japanese Patent No. 3095620

  SUMMARY OF THE INVENTION An object of the present invention is to provide a wastewater treatment method and a wastewater treatment apparatus that can improve the treatment efficiency of nitrogen wastewater containing hydrogen peroxide and that are energy-saving and can realize downsizing and running costs.

In order to solve the above problems, a wastewater treatment method of the present invention includes a microorganism treatment step of treating a nitrogen wastewater containing hydrogen peroxide using a submerged membrane,
A photocatalytic treatment step of photocatalytically treating the treated water derived from the submerged membrane.

  According to the wastewater treatment method of the present invention, after performing the microorganism treatment using the submerged membrane on the nitrogen wastewater containing hydrogen peroxide, the photocatalytic treatment is further performed. By this photocatalytic treatment, nitrogen wastewater containing hydrogen peroxide can be treated at a high level beyond the limit of water quality of treatment by microbial treatment. Therefore, according to the wastewater treatment method of the present invention, the treatment efficiency of nitrogen wastewater containing hydrogen peroxide can be improved, and energy saving, compactness, and reduction of running cost can be realized as compared with the prior art.

Moreover, the waste water treatment apparatus of one embodiment has a submerged film while introducing nitrogen waste water containing hydrogen peroxide, and a microorganism treatment unit that performs microorganism treatment of the nitrogen waste water,
A treatment water derived from the submerged membrane of the microorganism treatment part is introduced, and a photocatalyst part for photocatalytically treating the treatment water is provided.

  According to the wastewater treatment apparatus of this embodiment, after the microorganism treatment is performed on the nitrogen wastewater containing hydrogen peroxide by the microorganism treatment unit having a submerged film, the photocatalyst treatment is further performed by the photocatalyst unit. By this photocatalytic treatment, nitrogen wastewater containing hydrogen peroxide can be treated at a high level beyond the limit of water quality of treatment by microbial treatment. Therefore, according to the waste water treatment apparatus of the present invention, the treatment efficiency of nitrogen waste water containing hydrogen peroxide can be improved, and energy saving, compactness, and reduction of running cost can be realized as compared with the prior art.

  Moreover, the waste water treatment method of one embodiment adds aminoethanol containing waste water to the nitrogen waste water and treats it.

  According to the wastewater treatment method of this embodiment, aminoethanol-containing wastewater is added to the nitrogen wastewater for treatment. Therefore, at the same time that the aminoethanol-containing wastewater is treated, this aminoethanol replaces methanol, so that it is not necessary to add methanol as a hydrogen donor necessary for the denitrification treatment, and the running cost can be reduced.

  Moreover, the wastewater treatment method of one embodiment treats the nitrogen wastewater by adding biologically treated treated water or sludge generated by biological treatment.

  According to the wastewater treatment method of this embodiment, the activity of various microorganisms can be enhanced in the microorganism treatment step. That is, the activity of microorganisms can be enhanced by the mineral contained in the treated water or sludge by the biological treatment.

Moreover, in the wastewater treatment apparatus of one embodiment, the microorganism treatment unit is
An adjustment tank into which the nitrogen drainage is introduced;
A denitrification tank having an agitating part for introducing treated water from the adjustment tank and agitating by an air lift method,
The treatment water from the denitrification tank is introduced and has a nitrification tank having a stirring portion for stirring by an air lift method.
The stirring unit of the denitrification tank includes a separation wall disposed between an upper part and a lower part of the denitrification tank, a partition plate extending vertically in the denitrification tank, and an air diffuser pipe disposed between the upper part and the lower part. Including
The stirring section of the nitrification tank includes a separation wall disposed between an upper part and a lower part of the nitrification tank, a partition plate extending vertically in the nitrification tank, and an air diffuser disposed between the upper part and the lower part. including.

  According to the wastewater treatment apparatus of this embodiment, the denitrification tank and the nitrification tank have an air lift type agitation unit utilizing a partition plate and an air diffuser. Thereby, in the denitrification tank and the nitrification tank, microorganisms are cultured at a high concentration of, for example, 15000 ppm in the MLSS (mixed liquid suspension substance) concentration, and even when it cannot be sufficiently stirred with a normal stirrer or a circulation pump, Stirring in each water tank can be performed efficiently. Therefore, the microbial reaction can sufficiently proceed. In addition, it is possible to concentrate the microorganism concentration in each lower part to a high concentration by the principle of natural sedimentation, while minimizing the influence of aeration by the air diffuser on the upper part of the denitrification tank and the upper part of the nitrification tank on each lower part. .

  In addition, since the aeration by the diffuser installed in the denitrification tank is for stirring the tank while maintaining the anaerobic state of the denitrification tank, it was connected to the diffuser installed in the denitrification tank The blower may be operated intermittently. On the other hand, the aeration by the diffuser installed in the nitrification tank is for agitating the inside of the nitrification tank and ensuring the dissolved oxygen concentration in the nitrification tank, so it is connected to the diffuser installed in the nitrification tank. The blower that has been used may be operated continuously.

  Moreover, in the waste water treatment apparatus of one Embodiment, the microorganisms concentration in the said microorganism treatment part shall be 15000 ppm or more by MLSS (mixed-liquid suspension material) density | concentration.

  According to the waste water treatment apparatus of this embodiment, biotoxic ammonia and aminoethanol can be efficiently treated.

  In one embodiment of the waste water treatment apparatus, the photocatalyst unit is a photocatalyst tank having an ultraviolet irradiation unit and a photocatalyst plate that contacts the treated water and is irradiated with ultraviolet rays from the ultraviolet irradiation unit.

  According to the wastewater treatment apparatus of this embodiment, the effect of the photocatalytic treatment can be further enhanced by irradiating the photocatalyst plate with ultraviolet rays from the ultraviolet irradiation unit.

  Moreover, in the waste water treatment apparatus of one Embodiment, the said microorganisms treatment part has a diffuser pipe which is arrange | positioned under the said submerged membrane, wash | cleans the said submerged membrane, and stirs treated water.

  According to this waste water treatment apparatus, since it is possible to wash the submerged membrane and agitate the microorganism treatment unit with one aeration tube, the initial cost can be reduced, and the washing air can also be used as agitation air. Running costs can be reduced.

  Moreover, in the waste water treatment apparatus of one Embodiment, the photocatalyst board which the said photocatalyst tank has is inorganic porous.

  According to the wastewater treatment apparatus of this embodiment, since the photocatalyst plate is inorganic porous, the surface area (contact area) is large, and the reaction efficiency by the photocatalyst can be increased.

  Moreover, in the waste water treatment apparatus of one Embodiment, it has a return part which returns the treated water photocatalyzed by the photocatalyst part to the denitrification tank of the microorganism treatment part.

  According to the wastewater treatment apparatus of this embodiment, the return unit returns the treated water photocatalyzed in the photocatalyst tank to the denitrification tank, so that the treated water can be circulated, and in particular, the treatment efficiency in the denitrification tank. Can be increased.

  Moreover, in the waste water treatment apparatus of one Embodiment, it has a return part which returns the treated water photocatalyzed by the photocatalyst part to the nitrification tank of the microorganism treatment part.

  According to the wastewater treatment apparatus of this embodiment, since the return unit returns the treated water photocatalyzed in the photocatalyst tank to the nitrification tank, the treated water can be circulated, and in particular, the treatment efficiency in the nitrification tank Can be increased.

Further, in waste water treatment apparatus of an embodiment, the intensity of ultraviolet the ultraviolet irradiation unit irradiates the photocatalyst plate, it was 1 mW / cm ² of about or 500 W / cm ² to 3 mW / cm ^2.

  According to the waste water treatment apparatus of this embodiment, the effect of the photocatalyst treatment by the photocatalyst plate can be sufficiently exhibited.

  In one embodiment, the photocatalyst plate is made of any one compound of titanium oxide, zinc oxide, niobium oxide, strontium titanate, potassium tantalate, and tungsten oxide.

  According to the wastewater treatment apparatus of this embodiment, advanced wastewater treatment can be realized by the action of a useful photocatalyst utilizing the characteristics of each of the above compounds.

  Moreover, in the waste water treatment method of one embodiment, the nitrogen waste water is waste water containing micro-nano bubbles.

  According to the wastewater treatment method of this embodiment, since the nitrogen wastewater contains micro-nano bubbles, when the microorganisms are treated with nitrogen wastewater in the microorganism treatment step, microorganisms can be activated with the micro-nano bubbles, and the treatment efficiency by the microorganisms is improved. it can.

  Moreover, in the waste water treatment apparatus of one Embodiment, the said nitrogen waste_water | drain is the waste water containing a micro nano bubble.

  According to the wastewater treatment apparatus of this embodiment, since the nitrogen wastewater contains micro / nano bubbles, when the microorganism waste treatment unit performs the microorganism treatment of the nitrogen waste water, the microorganisms can be activated by the micro / nano bubbles and the treatment efficiency by the microorganisms is improved. it can.

  Moreover, in the waste water treatment apparatus of one Embodiment, the to-be-processed water from the said denitrification tank was introduce | transduced, and the micro-nano bubble generation tank to introduce into the said nitrification tank after making the said to-be-processed water contain a micro nano bubble was provided.

  According to the wastewater treatment apparatus of this embodiment, the micro / nano bubble generation tank introduces the micro / nano bubbles into the treated water from the denitrification tank and then introduces it into the nitrification tank. Can be efficiently nitrified.

  According to the wastewater treatment method of the present invention, after performing the microorganism treatment using the submerged membrane on the nitrogen wastewater containing hydrogen peroxide, the photocatalytic treatment is further performed. By this photocatalytic treatment, nitrogen wastewater containing hydrogen peroxide can be treated at a high level beyond the limit of water quality of treatment by microbial treatment. Therefore, according to the wastewater treatment method of the present invention, the treatment efficiency of nitrogen wastewater containing hydrogen peroxide can be improved, and energy saving, compactness, and reduction of running cost can be realized as compared with the prior art.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 schematically shows a first embodiment of the wastewater treatment apparatus of the present invention. The first embodiment includes an adjustment tank 1, a denitrification tank 3, a nitrification tank 11 having a submerged film 16, and a photocatalyst tank 18.

  Examples of the adjustment tank 1 include high-concentration nitrogen wastewater containing hydrogen peroxide and aminoethanol-containing wastewater from a CMP (chemical mechanical polishing) process in a semiconductor factory. In addition, biological treatment water that has been subjected to biological treatment or slurry-like biological treatment sludge generated by biological treatment is also introduced into the adjustment tank 1. The high-concentration nitrogen wastewater containing hydrogen peroxide includes high-concentration ammonia-containing wastewater containing hydrogen peroxide. In this adjustment tank 1, the amount and quality of the wastewater introduced are adjusted.

  By introducing the biological treatment water or biological treatment sludge into the adjustment tank 1, trace elements such as phosphorus, potassium, calcium, magnesium contained in the biological treatment water or biological treatment sludge are removed from the denitrification tank 3 or nitrification. The activity of all the microorganisms in the tank of the tank 11 will be promoted. In particular, in high-concentration microbial treatment using the submerged membrane 16 in the nitrification tank 11, if the trace element is not contained in the water to be treated, the activity of the microorganism is small and the microbial treatment is not stable.

  In addition, by introducing aminoethanol-containing wastewater into the adjustment tank 1, treatment of aminoethanol, which is a harmful substance, is naturally treated, and at the same time, nitrogen in aminoethanol is treated as a hydrogen donor in the denitrification tank 3. Available. In general, methanol is often used as the hydrogen donor, but in this embodiment, aminoethanol substitutes for methanol, so it is not necessary to add methanol as a hydrogen donor necessary for denitrification treatment. Running costs can be reduced.

  Moreover, the adjustment tank pump 2 is installed in the adjustment tank 1, and this adjustment tank pump 2 introduces to-be-processed water from the adjustment tank 1 to the lower part 8 of the denitrification tank 3. FIG. That is, toxic hydrogen peroxide-containing high-concentration nitrogen wastewater such as hydrogen peroxide-containing high-concentration ammonia-containing wastewater as the treated water has a higher microorganism concentration due to gravity than the upper part 9 of the denitrification tank 3. It introduce | transduces into the lower part 8 of the denitrification tank 3 used as the density | concentration. Thereby, the irritation | stimulation which a hydrogen peroxide containing high concentration nitrogen waste_water | drain gives to microorganisms can be decreased, and it is suitable for microorganisms processing.

  The denitrification tank 3 includes a separation wall 4A disposed between the upper portion 9 and the lower portion 8, a partition plate 6 extending vertically from the upper portion 9 to the lower portion 8, and a dust disposed between the upper portion 9 and the lower portion 8. And trachea 5. The separation wall 4A, the partition plate 6, and the air diffusion pipe 5 constitute an air lift type stirring unit. The air diffuser 5 is connected to a denitrification tank blower 7, and discharge air is supplied from the blower 7. That is, a water flow along the partition plate 6 is generated by air bubbles discharged from the air diffuser 5. That is, in this denitrification tank 3, in FIG. 1, an ascending water flow W <b> 1 is generated in the area where the diffuser pipe 5 on the right side of the partition plate 6 is installed, and a descending water flow W <b> 2 is generated in the area on the left side of the partition plate 6. According to the air lift type agitator utilizing the partition plate 6 and the air diffuser 5, even if the microorganism concentration in the denitrification tank 3 is as high as 15000 ppm or more in MLSS (Mixed Liquor Suspended Solid), the denitrification tank Stirring in the denitrification tank 3 can be performed efficiently so that a portion where stirring cannot be performed in the so-called dead space is not formed. The denitrification tank blower 7 is based on intermittent operation set by a timer or the like according to the necessity of stirring and aeration in the tank.

  Since the separation wall 4 is installed on the side wall of the denitrification tank 3, the stirring by the stirring unit proceeds more smoothly in the upper part 9 of the denitrification tank 3 than in the lower part 8 of the denitrification tank 3. . The lower part 8 of the denitrification tank 3 requires a certain amount of stirring, but the lower part 8 of the denitrification tank 3 concentrates microorganisms to a high concentration by natural sedimentation. Therefore, it is better that the lower part 8 of the denitrification tank 3 has less stirring compared to the upper part 9 of the denitrification tank 3.

  In addition, a high-concentration return containing microorganisms is returned to the lower part 8 of the denitrification tank 3 from the lower hopper part 24 of the lower semi-anaerobic part 13 of the nitrification tank 11 by the return sludge pump 10 and the return sludge pipe L10. A large amount of sludge is introduced. The return sludge section constituted by the return sludge pump 10 and the return sludge pipe L10 moves the semi-anaerobic sludge at the lower part of the nitrification tank 11 to the lower part 8 of the denitrification tank 3 without exposing it to oxygen in the air at all. be able to. In addition, since the lower hopper part 24 of the semi-anaerobic part 13 has a hopper-like (funnel-like) structure, it is easy to collect the precipitated sludge in the central part and easily introduce it into the sludge return pipe L10 connected to the lowermost part.

  The high-concentration nitrogen drainage introduced into the denitrification tank 3 is anaerobically treated in the lower part 8 and then introduced into the semi-anaerobic part 13 at the lower part of the nitrification tank 11 by natural flow from the upper part 9 of the denitrification tank 3. .

  The nitrification tank 11 includes a lower semi-anaerobic part 13, an upper aerobic part 12, a separation wall 4B installed between the upper part and the lower part, and an upper aerobic part 12 to a lower semi-aerobic part 13. And a partition plate 14 extending. A diffuser tube 15 is disposed between the partition plate 14 and the separation wall 4B, and between the upper aerobic portion 12 and the lower semi-anaerobic portion 13. A submerged membrane 16 is disposed above the diffuser tube 15. Has been placed. The air diffuser 15 is connected to a nitrification tank blower 21. Further, a gravity pipe 17 is connected to the submerged film 16 as a pipe for leading the treated water.

  The combination of the air diffusion tube 15 and the partition plate 14 constitutes an air lift type stirring unit, and a water flow along the partition plate 14 is generated by the air discharged from the air diffusion tube 15. That is, in this nitrification tank 11, in FIG. 1, an upward water flow W <b> 11 is generated in the area on the right side of the partition plate 6, and a downward water flow W <b> 12 is generated in the area on the left side of the partition plate 6. Thereby, in the nitrification tank 11, even if the MLSS density | concentration of a treated water is a density | concentration of 15000 ppm or more, the inside in a tank can be performed.

  In this nitrification tank 11, since the submerged film 16 is installed in the aerobic part 12, the microorganisms remain in the nitrification tank 11 or are returned to the lower part 8 of the denitrification tank 3 by the return sludge pump 10. . The treated water discharged from the submerged membrane 16 is introduced into the photocatalyst tank 18 through the gravity pipe 17. Since the gravity pipe 17 is a system that uses the water head difference to discharge the treated water, it does not require electric power, and energy saving operation is possible.

  On the other hand, the return sludge transferred to the denitrification tank 3 by the return sludge pump 10 is a method using a normal pump, and a large amount of return sludge can be transferred without being exposed to air. Anaerobic can be reliably maintained. The microbial sludge returned to the lower part 8 of the denitrification tank 3 passes through the upper part 9 of the denitrification tank 3 and returns to the semi-anaerobic part 13 of the nitrification tank 11 to be circulated. By circulating microbial sludge in both the denitrification tank 3 and the nitrification tank 11, the microbial concentration in both tanks is maintained at substantially the same concentration. As described above, when the microorganism concentration is as high as 15,000 ppm or more in MLSS (Mixed Liquor Suspended Solid) concentration, as a countermeasure against the occurrence of a dead space where stirring cannot be performed with a normal stirrer, submerged stirrer, and circulation pump. The entire agitating of the air lift type tank by the combination of the partition plate 14 and the air diffuser 15 is performed.

  Since the separation wall 4B is installed on the side wall of the nitrification tank 11, when the aerobic part 12 and the semi-anaerobic part 13 are compared, the aerobic part 12 is stirred by the rising water flow W11 and the falling water flow W12. It is progressing smoothly. The semi-anaerobic portion 13 concentrates microorganisms to a high concentration by sedimentation by natural sedimentation. Therefore, the semi-anaerobic part 13 needs a certain amount of stirring, but it is better that the stirring is less than that of the aerobic part 12.

  The microorganism concentration in both the denitrification tank 3 and the nitrification tank 11 is maintained at 15000 ppm or more by MLSS (Mixed Liquor Suspended Solid).

  In addition, although returning to the former, the denitrification tank 3 is provided with an oxidation-reduction potentiometer (not shown) in order to measure the anaerobic degree. In the denitrification tank 3, nitrate nitrogen in the treated water introduced from the semi-anaerobic portion 13 of the nitrification tank 11 by the return sludge pump 10 is converted into nitrogen gas by anaerobic microorganisms in the presence of aminoethanol as a hydrogen donor. It is reduced until. Nitrate nitrogen in the treated water is a nitrification tank 11 in which hydrogen peroxide-containing high-concentration ammonia wastewater or aminoethanol as hydrogen peroxide-containing high-concentration nitrogen wastewater is decomposed by microorganisms into nitrate nitrogen. It is.

  In the denitrification tank 3, organic substances other than aminoethanol are biologically decomposed by anaerobic microorganisms. Next, the treated water flowing out from the upper part 9 of the denitrification tank 3 is introduced into the semi-anaerobic part 13 which is the lower part of the nitrification tank 11. Here, the anaerobic part is a state where there is no dissolved oxygen, the aerobic part is a state where the dissolved oxygen is maintained at several ppm, and the semi-anaerobic part is 0 ppm of dissolved oxygen or there is dissolved oxygen. However, it is defined as about 0.5 ppm.

  As described above, in the aerobic portion 12 at the upper part of the nitrification tank 11, the water flows W11 and W12 are generated by the air discharged from the diffuser tube 15, but these water flows W11 and W12 are somewhat different from the lower semi-anaerobic portion 13. However, more than the aerobic part 12 is not affected by the presence of the separation wall 4B. Since the microbial concentration in the nitrification tank 11 is high, the influence on the semi-anaerobic part 13 due to the water flow in the aerobic part 12 is minimized even with the separation wall 4B having a size as shown in FIG. be able to.

  Further, as described above, the nitrification tank 11 has the semi-anaerobic portion 13 at the lower portion. Thereby, in the circulation system by the return sludge pump 10 between the denitrification tank 3 and the nitrification tank 11, the anaerobic microorganisms which move to the nitrification tank 11 together with the treated water treated by the anaerobic microorganisms in the denitrification tank 3, It will be introduced into the aerobic part 12 through the semi-anaerobic part 13. Therefore, compared with the case where the moving anaerobic microorganisms are introduced straight into the aerobic part 12, the environmental stress on the anaerobic microorganisms can be reduced, and the efficiency in treating nitrogen with the anaerobic microorganisms can be improved. .

  In addition, in the semi-anaerobic part 13, microorganisms specific to the semi-anaerobic part 13 are propagated, and by treating the water to be treated with various microorganisms that propagate in the semi-anaerobic part 13 as well as anaerobic microorganisms and aerobic microorganisms, The efficiency of microbial treatment can be improved comprehensively. Moreover, it discovered that the microorganism which propagates in the semi-anaerobic part 13 is useful for the reduction | decrease of sludge by providing the semi-anaerobic part 13 in the nitrification tank 11. FIG.

  Since the aeration pipe 15 as an aeration facility is not installed in the lower part of the semi-anaerobic part 13, although the semi-anaerobic part 13 is not aerated, the influence of some water flow in the upper aerobic part 12 being aerated is affected. receive. Thereby, in the semi-anaerobic part 13, the dissolved oxygen which is the condition of the semi-anaerobic part is 0 ppm, or about 0.5 ppm even if dissolved oxygen is present. Thereby, in the semi-anaerobic part 13, semi-anaerobic property can be maintained.

  Further, in the aerobic part 12 at the upper part of the nitrification tank 11, an air diffuser 15 is installed below the submerged film 16. The air diffuser 15 is supplied with air discharged from the nitrification blower 21. The submerged film 16 is washed with air by the air discharged from the air diffuser 15. As this submerged membrane 16, for example, two types, a flat membrane type and a hollow fiber membrane, are commercially available. In the aerobic part 12 of the nitrification tank 11, ammonia nitrogen in the water to be treated is decomposed and oxidized by aerobic microorganisms to become nitrate nitrogen or nitrite nitrogen. The treated water treated in the nitrification tank 11 naturally flows out from the gravity piping 17 connected to the submerged membrane 16 by gravity. That is, this gravity piping 17 derives treated water using a water head difference. Since the method using the water head difference does not require electric power, energy-saving operation is possible.

  Further, in the nitrification tank 11, when the amount of permeated water of the submerged membrane 16 is reduced, that is, when the amount of treated water is reduced, the submerged membrane 16 itself is washed with sodium hypochlorite or the like. Then, treated water from the gravity pipe 17 is introduced into the photocatalyst tank 18.

  In the photocatalyst tank 18, a UV light generation unit 19 as an ultraviolet irradiation unit is installed on an upper part 18 </ b> A (that is, a part not in contact with the liquid) of the photocatalyst tank 18 that is not submerged. The photocatalyst tank 18 has a photocatalyst plate 20 that comes into contact with the treated water and is irradiated with ultraviolet rays from the UV light generation unit 19. As an example, the UV light generation unit 19 can employ an ultraviolet lamp or a black light. The UV light generator 19 may be provided with a necessary number of ultraviolet lamps or black lights that can irradiate ultraviolet rays with sufficient intensity. Further, the installation position of the UV light generation unit 19 is set at a position about 5 cm to 1 m above the surface of the treated water in the photocatalyst tank 18. The UV light generation unit 19 may be a mercury lamp or a sunlight introduction unit.

As the intensity of the ultraviolet this UV light generating unit 19 irradiates, with respect to drainage of the irradiation target, as an example, was a 1 (mW / cm ^2), usually, 500μW ^/ cm 2 ~3mW ^/ cm The intensity of the ultraviolet light is about ² . Further, the intensity of ultraviolet light UV light generating unit 19 irradiates, may 50μW ^/ cm ² ~5mW ^/ cm 2 approximately.

  Next, as an example, the photocatalyst plate 20 in the photocatalyst tank 18 is a photocatalyst plate coated with a ceramic containing a compound such as titanium oxide, zinc oxide, niobium oxide, strontium titanate, potassium tantalate, and tungsten oxide. . The residence time of the treated water in the photocatalyst tank 18 varies depending on the target treated water quality concentration, but in this first embodiment, it is about 30 minutes to 2 hours.

  According to the waste water treatment apparatus of the first embodiment, the nitrogen waste water containing hydrogen peroxide is subjected to microbial treatment in the nitrification tank 11 having the submerged film 16 and then further subjected to photocatalytic treatment in the photocatalyst tank 18. . By this photocatalytic treatment, nitrogen wastewater containing hydrogen peroxide can be treated at a high level beyond the limit of water quality of treatment by microbial treatment. In addition, by irradiating the photocatalyst plate 20 with ultraviolet rays from the UV light generation unit 19, the effect of the photocatalyst treatment can be further enhanced.

  Therefore, according to the waste water treatment apparatus of the first embodiment, the treatment efficiency of nitrogen waste water containing hydrogen peroxide can be improved, and energy saving, compactness, and reduction of running cost can be realized as compared with the prior art.

(Second embodiment)
Next, FIG. 2 shows a second embodiment of the waste water treatment apparatus of the present invention. In this second embodiment, instead of the denitrification tank 3 and the nitrification tank 11 of the first embodiment described above, a denitrification tank 3N filled with a vinylidene chloride filling 23A and a nitrification tank 11N filled with a vinylidene chloride filling 23B. Only the point provided with is different from the first embodiment described above. Therefore, in this 2nd Embodiment, the same code | symbol is attached | subjected about the same part as 1st Embodiment, detailed description is abbreviate | omitted, and a different part from 1st Embodiment is demonstrated.

  In the second embodiment, the denitrification tank 3N is filled with a vinylidene chloride filler 23A from the upper part 9 to the lower part 8 on the side opposite to the diffuser pipe 5 with respect to the partition plate 6. Further, the nitrification tank 11N is filled with a vinylidene chloride filler 23B from the aerobic part 12 to the semi-anaerobic part 13 on the side opposite to the air diffuser 15 with respect to the partition plate 14.

  Thus, by filling the denitrification tank 3 and the nitrification tank 11 with the vinylidene chloride fillers 23A and 23B, the average concentration of the microorganisms in the denitrification tank 3 and the nitrification tank 11 is smaller than that in the case where there is no filler. High concentration. In addition, the microorganisms adhere to and propagate on the vinylidene chloride fillers 23A and 23B, so that the microorganisms are more stabilized and the nitrogen treatment capacity for the high-concentration nitrogen drainage is improved as compared with the state without the filler. In addition, it is preferable to arrange | position this vinylidene chloride filling 23A, 23B over the whole of each water tank. In this case, the microbial concentration can be propagated at a high concentration throughout each water tank.

  In this embodiment, microorganisms propagate on the vinylidene chloride fillings 23A and 23B with the passage of time from the trial operation of the apparatus. The microbial concentration on the surfaces of the vinylidene chloride fillers 23A and 23B becomes 30000 ppm or more, which leads to an improvement in nitrogen treatment efficiency. The material of the vinylidene chloride fillings 23A and 23B is vinylidene chloride which is strong and not affected by chemical substances, and can be used semipermanently. Examples of the vinylidene chloride filling 23 include products such as biocodes, ring laces, biomulti-leafs, biomodules, and the like, which may be selected according to the properties of the waste water.

(Third embodiment)
Next, FIG. 3 shows a third embodiment of the waste water treatment apparatus of the present invention. The third embodiment is different from the first embodiment described above in that a pit 25, a pit pump 26, and a return pipe L20 are installed in the subsequent stage of the photocatalyst tank 18.

  In the third embodiment, treated water from the outlet of the photocatalyst tank 18 is introduced into the pit 25. A part of the treated water introduced into the pit 25 is returned to the aerobic portion 12 at the upper part of the nitrification tank 11 via the pit pump 25 and the return pipe L20. Thereby, since the returned treated water is processed again in the nitrification tank 11, the quality of the treated water can be improved.

(Fourth embodiment)
Next, FIG. 4 shows a fourth embodiment of the waste water treatment apparatus of the present invention. The fourth embodiment is different from the first embodiment described above in that a pit 25, a pit pump 26, and a return pipe L30 are installed at the subsequent stage of the photocatalyst tank 18.

  In the fourth embodiment, treated water from the outlet of the photocatalyst tank 18 is introduced into the pit 25. A part of the treated water introduced into the pit 25 is returned to the denitrification tank 3 via the pit pump 25 and the return pipe L30. Accordingly, the returned treated water is treated again in the denitrification tank 3 and the nitrification tank 11. Therefore, the treatment water quality can be further improved by the repeated treatment in the denitrification tank 3 and the nitrification tank 11.

  In the first to fourth embodiments, as shown by solid lines in FIGS. 1 to 4, the semi-anaerobic portion at the lower part of the nitrification tank 11 from the upper part 9 of the denitrification tank 3 through the flow paths 41, 42, 43. In the case where the nitrogen drainage is introduced into the flow path 13, instead of the flow path 42, when the flow path 37 drawn by a one-dot chain line, the micro / nano bubble generation tank 34, and the flow path 38 drawn by a one-dot chain line are provided, This is a modification of the fourth embodiment.

In this modification, the water to be treated from the upper part 9 of the denitrification tank 3 is introduced into the micro / nano bubble generation tank 34 through the flow path 41 and the flow path 38 under natural flow. As shown in FIGS. 1 to 4, a micro / nano bubble generator 31 is installed in the micro / nano bubble generation tank 34, and air from an air suction pipe 33 is adjusted by a valve 32 in the micro / nano bubble generator 31. While being introduced. In addition, the water to be treated in the micro / nano bubble generation tank 34 is supplied to the micro / nano bubble generator 31 from the water supply pipe 36 by the circulation pump 30 at a pressure of, for example, 1.5 kg / cm ² or more. Thereby, the micro / nano bubble generator 31 efficiently generates micro / nano bubbles. Therefore, in the micro / nano bubble generation tank 34, the water to be treated is made to contain micro / nano bubbles, and the water to be treated containing the micro / nano bubbles is supplied to the nitrification tank by the micro / nano bubble generation tank pump 35 via the flow path 37 and the flow path 43. 11 is introduced. Thereby, the aerobic microorganisms breeding in the nitrification tank 11 are activated by the micro / nano bubbles, and the nitrification efficiency of ammonia nitrogen can be dramatically improved.
Here, the micro / nano bubble generator 31 is operated by, for example, a timer (for example, about 20 minutes / day), so that no stress is applied to the anaerobic microorganisms. Further, the semi-anaerobic state of the semi-anaerobic portion 13 can be prevented from being destroyed by the timer operation (for example, 20 minutes / day or less than 20 minutes / day).

  Further, in the above modification, a micro-nano bubble generation tank similar to the above-described micro-nano bubble generation tank 34 is installed in the previous stage of the adjustment tank 1, and nitrogen drainage containing micro-nano bubbles is introduced into the adjustment tank 1. Good. In this case, the activity of all microorganisms in the denitrification tank 3 and the nitrification tank 11 can be promoted by the micro / nano bubbles contained in the nitrogen waste water, and the microorganism treatment can be promoted.

  In the first to fourth embodiments, the micro / nano bubble generator 31, the air suction pipe 33, the circulation pump 30, and the water supply pipe 36 are located near the air diffuser 15 </ b> A of the aerobic section 12 in the nitrification tank 11. A micro / nano bubble generator, an air suction pipe, a circulation pump, and a water supply pipe may be arranged to generate micro / nano bubbles in the aerobic part 12.

(Experimental example)
An experimental apparatus having the same structure as the waste water treatment apparatus of the first embodiment shown in FIG. 1 was manufactured. In this experimental apparatus, the capacity of the adjustment tank 1 is 50 liters, the capacity of the denitrification tank 3 is 100 liters, the capacity of the nitrification tank 11 is 200 liters, and the capacity of the photocatalyst tank 18 is 20 liters. After the training of microorganisms in this experimental apparatus for about two months, the microorganism concentration is set to 22000 ppm, and the high concentration nitrogen wastewater containing hydrogen peroxide with a nitrogen concentration of 3320 ppm discharged from the factory production equipment is used as treated water. Then, it was continuously introduced into the adjusting tank 1 together with the aminoethanol-containing waste water and the biological treatment sludge.

  Then, after waiting for the water quality to stabilize for one month, the nitrogen concentration at the outlet of the photocatalyst tank 18 was measured and found to be 8 ppm.

  FIG. 5A shows an example of a time chart when the nitrogen concentration in the hydrogen peroxide-containing high-concentration nitrogen drainage in the first to fourth embodiments is 2000 ppm and the hydrogen peroxide concentration is 10 ppm. FIG. 5B shows an example of a time chart when the nitrogen concentration in the hydrogen peroxide-containing high-concentration nitrogen drainage in the first to fourth embodiments is 4000 ppm and the hydrogen peroxide concentration is 20 ppm.

It is a figure which shows typically 1st Embodiment of the waste water treatment equipment of this invention, and its modification. It is a figure which shows typically 2nd Embodiment of the waste water treatment equipment of this invention, and its modification. It is a figure which shows typically 3rd Embodiment of the waste water treatment equipment of this invention, and its modification. It is a figure which shows typically 4th Embodiment of the waste water treatment equipment of this invention, and its modification. It is an example of the time chart in case the nitrogen concentration in the hydrogen peroxide containing high concentration nitrogen waste_water | drain in the said 1st-4th embodiment is 2000 ppm, and a hydrogen peroxide concentration is 10 ppm. It is an example of the time chart in case the nitrogen concentration in the hydrogen peroxide containing high concentration nitrogen waste_water | drain in the said 1st-4th embodiment is 4000 ppm and hydrogen peroxide concentration is 40 ppm.

Explanation of symbols

1 Adjustment tank 2 Adjustment tank pump
3, 3N Denitrification tank 4A, 4B Separation wall 5 Aeration pipe 6 Partition plate 7 Denitrification tank blower 8 Denitrification tank lower part 9 Denitrification tank upper part 10 Return sludge pump 11, 11N Nitrification tank 12 Aerobic part 13 Semi-anaerobic part 14 Partition plate 15 Aeration pipe 16 Submerged film 17 Gravity pipe 18 Photocatalyst tank 19 UV light generation part 20 Photocatalyst plate 21 Nitrification tank blower 23A, 23B Filling with vinylidene chloride 24 Lower hopper part 25 Pit 26 Pit pumps W1, W2, W11, W12 Water flow 30 Circulation Pump 31 Micro-nano bubble generator 32 Valve 33 Air suction pipe 34 Micro-nano bubble generation tank 35 Micro-nano bubble generation tank pump 36 Water supply pipe 37, 38, 41-43 Flow path

Claims (16)

A microbial treatment process for treating microbial wastewater containing hydrogen peroxide using a submerged membrane;
A wastewater treatment method comprising: a photocatalytic treatment step of photocatalytically treating treated water derived from the submerged membrane. A microbial treatment section for introducing a nitrogen wastewater containing hydrogen peroxide and having a submerged membrane to microbially treat the nitrogen wastewater;
A wastewater treatment apparatus comprising: a treated water derived from a submerged membrane of the microorganism treatment unit; and a photocatalyst unit for photocatalytically treating the treated water. The waste water treatment method according to claim 1,
A wastewater treatment method characterized by adding aminoethanol-containing wastewater to the nitrogen wastewater for treatment. The waste water treatment method according to claim 1,
A wastewater treatment method characterized by adding and treating biologically treated water or sludge generated by biological treatment to the nitrogen wastewater. The waste water treatment apparatus according to claim 2,
The microorganism treatment unit is
An adjustment tank into which the nitrogen drainage is introduced;
A denitrification tank having an agitating part for introducing treated water from the adjustment tank and agitating by an air lift method,
The treatment water from the denitrification tank is introduced and has a nitrification tank having a stirring portion for stirring by an air lift method.
The stirring unit of the denitrification tank includes a separation wall disposed between an upper part and a lower part of the denitrification tank, a partition plate extending vertically in the denitrification tank, and an air diffuser pipe disposed between the upper part and the lower part. Including
The stirring section of the nitrification tank includes a separation wall disposed between an upper part and a lower part of the nitrification tank, a partition plate extending vertically in the nitrification tank, and an air diffuser disposed between the upper part and the lower part. A wastewater treatment apparatus comprising: The waste water treatment apparatus according to claim 2,
A wastewater treatment apparatus characterized in that the microorganism concentration in the microorganism treatment section is 15000 ppm or more in terms of MLSS (mixed liquid suspended substance) concentration. The waste water treatment apparatus according to claim 2,
The photocatalyst part is
An ultraviolet irradiation unit;
A wastewater treatment apparatus, comprising a photocatalyst tank in contact with the treated water and having a photocatalyst plate irradiated with ultraviolet rays from the ultraviolet irradiation unit. The waste water treatment apparatus according to claim 2,
The microorganism treatment unit is
A wastewater treatment apparatus, which is disposed below the submerged membrane and has an air diffuser for washing the submerged membrane and stirring the treated water. The waste water treatment apparatus according to claim 7,
A wastewater treatment apparatus, wherein the photocatalyst plate of the photocatalyst tank is inorganic porous. The waste water treatment apparatus according to claim 5,
A wastewater treatment apparatus comprising a return unit that returns treated water photocatalyzed by the photocatalyst unit to a denitrification tank of the microorganism treatment unit. The waste water treatment apparatus according to claim 5,
A wastewater treatment apparatus comprising a return unit that returns treated water photocatalyzed by the photocatalyst unit to a nitrification tank of the microorganism treatment unit. The waste water treatment apparatus according to claim 7,
Waste water treatment apparatus, characterized in that the ultraviolet irradiation unit is an intensity of the irradiated ultraviolet ray to the photocatalyst plate, it was 1 mW / cm ² of about or 500 W / cm ² to 3 mW / cm ^2. The waste water treatment apparatus according to claim 7,
The waste water treatment apparatus, wherein the photocatalyst plate is made of any one compound of titanium oxide, zinc oxide, niobium oxide, strontium titanate, potassium tantalate, and tungsten oxide. The waste water treatment method according to claim 1,
The nitrogen waste water is waste water containing micro / nano bubbles. The waste water treatment apparatus according to claim 2,
The waste water treatment apparatus, wherein the nitrogen waste water is waste water containing micro / nano bubbles. The waste water treatment apparatus according to claim 5,
A wastewater treatment apparatus comprising a micro / nano bubble generation tank that introduces water to be treated from the denitrification tank and introduces micro / nano bubbles into the water to be treated and then introduces the water into the nitrification tank.

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