JP6532718B2 - Water treatment apparatus and water treatment method - Google Patents

Description

  The present invention relates to a water treatment apparatus and a water treatment method using anaerobic ammonia oxidizing bacteria.

  Heretofore, as a method of biologically removing nitrogen components in water to be treated, anaerobic ammonia oxidation treatment using anaerobic ammonia oxidizing bacteria is known. Anaerobic ammonia oxidation treatment converts ammonia nitrogen and nitrite nitrogen into nitrogen gas under the anaerobic condition by the action of the anaerobic ammonia oxidizing bacteria which are autotrophic denitrifying bacteria, and the nitrogen component of the treated water Is a method of removing Anaerobic ammonia oxidation treatment does not require the addition of an organic component (hydrogen donor) such as methanol as compared with the treatment by nitrification denitrification method generally used widely for nitrogen removal, and oxygen supply by aeration It is an effective treatment method in that it can reduce the amount of sludge generation and can also reduce the amount of sludge generation. On the other hand, since anaerobic ammonia-oxidizing bacteria have a slow growth rate, it is important to keep the anaerobic ammonia-oxidizing bacteria as high as possible in the reaction tank in order to increase the treatment efficiency in anaerobic ammonia oxidation treatment. . For example, Patent Document 1 discloses that an anaerobic ammonia oxidizing bacterium is fixed to a carrier or granulated and held in a reaction tank to perform an anaerobic ammonia oxidation treatment.

JP 2005-324132 A

  In the anaerobic ammonia oxidation treatment, it is possible to increase the contact efficiency between the anaerobic ammonia oxidizing bacteria and the water to be treated while suppressing the outflow from the reaction tank of the anaerobic ammonia oxidizing bacteria from the viewpoint of efficiently performing the treatment. It is preferable to do. Therefore, it becomes more important to properly control the flow of water in the reaction vessel.

  The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to have a reaction tank performing an anaerobic ammonia oxidation treatment, and to control the flow of water in the reaction tank suitably for a long period of time It is in providing a water treatment device. Further, the present invention provides a water treatment method capable of suitably controlling the flow of water over a long period of time when performing anaerobic ammonia oxidation treatment in which nitrogen-containing treated water is brought into contact with anaerobic ammonia oxidizing bacteria. Also aim.

The water treatment apparatus of the present invention which has been able to solve the above-mentioned problems has a reaction tank which brings the nitrogen-containing treated water into contact with the anaerobic ammonia oxidizing bacteria to carry out the anaerobic ammonia oxidation reaction. The present invention is characterized in that a water flow control member containing Al ₂ O ₃ as a main component is provided. In the water treatment apparatus of the present invention, since the water flow control member containing Al ₂ O ₃ as the main component is provided in the reaction tank, adhesion of bacteria to the surface of the water flow control member is suppressed, and the water flow control member is used. The function, that is, the function of controlling the flow of water in the reaction vessel can be exhibited over a long period of time.

  In the water treatment apparatus of the present invention, it is preferable to apply the water flow control member to the flow control member, from the viewpoint of suppressing the adhesion of the cells to the water flow control member and enhancing the treatment efficiency of the anaerobic ammonia oxidation treatment. In this case, it is preferable that the anaerobic ammonia oxidizing bacteria be retained on the downstream side of the water flow control member in the reaction tank, whereby the water flow control member can function as a rectifying material. As a result, the adhesion of the microbial cells to the surface of the water flow control member functioning as a rectifying material is suppressed, the rectifying effect is exhibited for a long period of time, and the contact efficiency between the water to be treated and the anaerobic ammonia oxidizing bacteria is high for a long period of time It becomes possible to maintain.

When the water flow control member is used as the flow straightening material, the above effect is particularly effectively exhibited in the upflow type reaction tank. For example, if part of the rectifying material is clogged in the upflow type reaction tank, the upward flow of the treated water is not well formed in the upper part (downstream side) of the clogged part, and a short circuit is likely to occur. . As a result, the entire inside of the tank can not be used effectively, and the anaerobic ammonia oxidation treatment performance may be degraded. However, by providing a rectifying material containing Al ₂ O ₃ as the main component in the upflow type reaction tank, clogging by cells of the rectifying material is less likely to occur, and anaerobic ammonia oxidation treatment is stabilized over a long period of time It is possible to do

  Anaerobic ammonia oxidizing bacteria are preferably fixed to a carrier and retained in the reaction vessel, or preferably granulated and retained in the reaction vessel. Thereby, anaerobic ammonia oxidation treatment can be performed efficiently.

Preferably, the water flow control member is granular, and a plurality of granular water flow control members are packed in the reaction tank to form a layer. When a plurality of granular water flow control members are packed to form a layer, the flow of water to be treated tends to be stagnant between the granular water flow control members, and the granular water flow control members are mainly composed of Al ₂ O ₃ By using the material, adhesion of the microbial cells to the surface of the water flow control member is suppressed, and clogging between the granular water flow control members is easily prevented.

The present invention is also a water treatment method for causing anaerobic ammonia oxidation reaction by bringing nitrogen-containing treated water into contact with anaerobic ammonia oxidizing bacteria, wherein water to be treated comprises Al ₂ O ₃ as a main component. The present invention also provides a water treatment method for controlling the flow of water to be treated by contacting the member. According to the water treatment method of the present invention, the adhesion of the microbial cells to the surface of the water flow control member is suppressed, and the flow of the water to be treated can be suitably controlled over a long period of time by the water flow control member. Further, when the water to be treated is brought into contact with the water flow control member and then brought into contact with the anaerobic ammonia oxidizing bacteria, the water flow control member functions as a rectifying material, and the water to be treated and the anaerobic ammonia oxidizing bacteria Contact efficiency can be maintained high over the long term.

According to the water treatment apparatus of the present invention, since the water flow control member containing Al ₂ O ₃ as the main component is provided in the reaction tank for performing the anaerobic ammonia oxidation treatment, the microbial cells on the surface of the water flow control member Adhesion is suppressed, and the flow of water in the reaction vessel can be suitably controlled over a long period of time. Further, according to the water treatment method of the present invention, adhesion of bacteria to the surface of the water flow control member is suppressed by using the water flow control member containing Al ₂ O ₃ as the main component when performing anaerobic ammonia oxidation treatment. And the flow of the water to be treated can be suitably controlled over a long period of time.

1 illustrates an exemplary configuration of a water treatment apparatus of the present invention.

In the present invention, a water treatment apparatus comprising a reaction tank for contacting nitrogen-containing treated water with anaerobic ammonia-oxidizing bacteria to perform an anaerobic ammonia oxidation reaction, and contacting nitrogen-containing treated water with anaerobic ammonia-oxidizing bacteria Water treatment method to perform anaerobic ammonia oxidation reaction. According to the present invention, when the anaerobic ammonia oxidation treatment is performed, the adhesion of the bacteria to the surface of the water flow control member is suppressed by using the water flow control member containing Al ₂ O ₃ as the main component, and the water to be treated Flow can be suitably controlled over a long period of time.

  In the present invention, the nitrogen-containing treated water is brought into contact with the anaerobic ammonia oxidizing bacteria to perform the anaerobic ammonia oxidation reaction. The treated water containing anaerobic ammonia oxidizing bacteria is held in the reaction tank which performs anaerobic ammonia oxidation treatment, and treatment with anaerobic ammonia oxidation reaction by contacting the treated water with anaerobic ammonia oxidizing bacteria It can be performed.

  The nitrogen-containing treated water contains at least ammonia nitrogen and preferably contains nitrite nitrogen. If the nitrogen-containing water to be treated contains both ammoniacal nitrogen and nitrite nitrogen, ammonia nitrogen and nitrite nitrogen are converted to nitrogen gas by the action of anaerobic ammonia oxidizing bacteria to be treated The nitrogen component in the water can be removed.

In anaerobic ammonia oxidation treatment, for example, a reaction represented by the following mass balance equation is considered to occur, and one equivalent of ammonia nitrogen and 1.32 equivalents of nitrite nitrogen react with each other to generate nitrogen molecules. Is generated, and the nitrogen component in the water to be treated is removed as a gas.
NH ₄ ⁺ +1.32 NO ₂ ⁻ +0.066 HCO ₃ ⁻ +0.13 H ⁺
→ 1.02 N ₂ + 0.26 NO ₃ ⁻ + 0.066 CH ₂ O _0.5 N _0.15 + 2.0 ₃ H ₂ O

  When the amount of nitrite nitrogen contained in the water to be treated is small, etc., it is preferable to partially nitrite ammonia nitrogen in the water to be treated, whereby ammonia nitrogen and nitrite in the water to be treated The content ratio of the reactive nitrogen can be adjusted to an appropriate range. For example, part of ammoniacal nitrogen in the water to be treated can be converted to nitrite nitrogen by performing pretreatment before the water to be treated is brought into contact with the nitrifying bacteria (ammonia oxidizing bacteria).

The shape and the like of the reaction tank are not particularly limited as long as the reaction water can be brought into contact with the anaerobic ammonia oxidizing bacteria. In addition, it is preferable that a reaction tank has a supply part of to-be-processed water, and a discharge part of treated water. In order to increase the contact efficiency between the water to be treated and the anaerobic ammonia oxidizing bacteria, the reaction tank is provided with stirring means such as a mechanical stirrer, or a circulation line connecting the water supply unit and the treatment water discharge unit. May be provided. In the latter case, the treated water is circulated between the reaction tank and the circulation line by returning a portion of the treated water discharged from the discharge unit to the treated water supply unit, and anaerobic ammonia oxidizing bacteria and The frequency of contact can be increased. In addition, it is preferable that a gas containing molecular oxygen (O ₂ ) such as air is not supplied to the water to be treated in the reaction tank from the viewpoint of adjusting the growth environment of the anaerobic ammonia oxidizing bacteria. It is preferable that the diffuser is not provided with a diffuser.

  In the reaction tank, the anaerobic ammonia-oxidizing bacteria may be suspended in the water to be treated in a dispersed state, or may be granulated (coarse-grained). Alternatively, the anaerobic ammonia oxidizing bacteria may be immobilized on the carrier, and in this case, the anaerobic ammonia oxidizing bacteria may be entrapped and immobilized on the carrier, or may be attached and immobilized on the carrier surface. The carrier may be fixed in the reaction vessel or non-fixed in the reaction vessel. As the carrier, fiber products (non-woven fabric, woven fabric, cords, etc.), plastics, sponges, carbides, gel bodies, etc. can be used. In addition, since anaerobic ammonia-oxidizing bacteria have a slow growth rate, it is preferable that the anaerobic ammonia-oxidizing bacteria be maintained at a high concentration in the reaction tank, from the viewpoint of efficient treatment. Therefore, it is preferable that the anaerobic ammonia oxidizing bacteria be granulated and held in the reaction vessel, or be fixed to a carrier and held in the reaction vessel.

  A flow control member is provided in the reaction tank. The water flow control member includes a straightening material for equalizing the flow of the treated water in the reaction tank, a baffle plate or guide plate for changing the flow of the treated water in the reaction tank, and the water in the reaction tank Overfill to support the packing material in the reaction tank and allow the treated water to permeate, a screen for preventing outflow of the carrier etc. from the reaction tank and separating treated water, and solid content such as sludge in the reaction tank The inclined board etc. which are made to settle are mentioned. By providing the water flow control member, the contact efficiency between the water to be treated and the anaerobic ammonia oxidizing bacteria can be enhanced, or the outflow amount of the anaerobic ammonia oxidizing bacteria from the reaction tank can be reduced.

In the present invention, at least one of the water flow control members is made of a material mainly composed of Al ₂ O ₃ . Then, by contacting with water flow control member mainly composed of Al ₂ O ₃ water to be treated, to control the flow of the water to be treated. As a result of investigations by the present inventors, in the reaction vessel in which the anaerobic ammonia oxidizing bacteria are retained, the water flow control member is made of a material containing Al ₂ O ₃ as a main component, whereby the bacterial cells (anaerobic It became clear that it became difficult for ammonia oxidation bacteria to adhere. For example, compared with the case of using a water flow control member made of another inorganic material, adhesion of the cells clearly becomes less likely to occur. Although the reason why such a result was obtained is not clear, the water flow control member is composed of a ceramic material having high stability in water (low reactivity) compared to metals, salts, etc. Among the ceramic materials, Al ₂ O ₃ has an isoelectric point to which anaerobic ammonia oxidizing bacteria do not easily adhere, that is, anaerobic ammonia oxidizing bacteria adhere electrostatically to Al ₂ O ₃ It may be difficult to do.

The water flow control member may contain other components as long as it contains Al ₂ O ₃ as a main component. For example, a binder or the like may be included to enhance formability, and another inorganic component may be included as a melting point depressant or the like to enhance the thermal processability of Al ₂ O ₃ . Furthermore, Al ₂ O ₃ may be contained as a composite oxide. The water flow control member preferably contains Al ₂ O ₃ at a content of 50% by mass or more, more preferably 70% by mass or more, still more preferably 85% by mass or more, and particularly preferably 95% by mass or more. The water flow control member may be made of only Al ₂ O ₃ .

According to the present invention, by forming the water flow control member from a material containing Al ₂ O ₃ as the main component, it is possible to suppress the adhesion of the cells to the water flow control member, but the effect is anaerobic ammonia oxidation treatment by the effect. It is preferable to apply such a water flow control member to the flow straightener in order to increase the treatment efficiency of That is, in the reaction tank, it is preferable to provide a rectifying material containing Al ₂ O ₃ as a main component. The rectifying material is preferably provided in the vicinity of the supply portion of the water to be treated, whereby the flow of the water to be treated in the reaction tank is made uniform to increase the contact efficiency between the water to be treated and the anaerobic ammonia oxidizing bacteria. Can. In this case, in the reaction tank, anaerobic ammonia oxidizing bacteria are held downstream of the rectifying material (water flow control member), and after the treated water is brought into contact with the rectifying material (water flow control member), anaerobic ammonia is obtained. It will be in contact with oxidizing bacteria. By forming the rectifying material from a material containing Al ₂ O ₃ as a main component, the adhesion of bacterial cells to the surface of the rectifying material can be suppressed, and the rectifying action by the rectifying material can be realized for a long time. As a result, the contact efficiency between the water to be treated and the anaerobic ammonia oxidizing bacteria can be maintained high over a long period of time.

When the rectifying material is made of a material containing Al ₂ O ₃ as a main component, the effect of suppressing the adhesion of bacterial cells to the rectifying material is exhibited particularly effectively in the upflow reaction tank. For example, when the rectifying material is not made of a material mainly composed of Al ₂ O ₃ , if a part of the rectifying material is clogged in the upflow reaction tank, the upper portion of the clogged portion (downstream side The shorting tends to occur because the upward flow of the treated water is not well formed. As a result, the entire inside of the tank can not be used effectively, and the anaerobic ammonia oxidation treatment performance may be degraded. However, in the upflow type reaction tank, by providing the rectifying material mainly composed of Al ₂ O ₃ , clogging with cells of the rectifying material is less likely to occur, and the anaerobic ammonia oxidation treatment is stabilized over a long period of time It is possible to do

  The shape or the like of the rectifying material can be a known one. For example, a plate provided with a plurality of openings (i.e., a rectifying plate) may be installed, and a plurality of granular rectifying materials are filled to form a layer. It is also good.

The effect of suppressing the adhesion of the bacteria to the water flow control member is particularly exhibited when the water flow control member in which the flow of the water to be treated tends to stagnate is used. As such a water flow control member, there is a granular one, and a plurality of such water flow control members in the reaction vessel are filled to form a layer. When a plurality of granular water flow control members are packed to form a layer, the flow of water to be treated tends to be stagnant between the granular water flow control members, and the granular water flow control members are mainly composed of Al ₂ O ₃ By using the material, adhesion of the microbial cells to the surface of the water flow control member is suppressed, and clogging between the granular water flow control members is easily prevented. In addition, the shape of a granular water flow control member is not specifically limited, Spherical shape, cylindrical shape, ring shape, an indeterminate form, etc. are mentioned.

  The structural example of the water treatment apparatus of this invention is demonstrated with reference to FIG. The present invention is not limited to the embodiment shown in FIG.

  The water treatment apparatus which has the reaction tank 1 provided with the supply part 2 which introduce | transduces the nitrogen-containing to-be-processed water 11 and the discharge part 3 which discharges the treated water 12 by FIG. 1 is shown. In the reaction tank 1, a carrier 4 to which anaerobic ammonia oxidizing bacteria are fixed is held. An anaerobic ammonia oxidation treatment is performed by introducing the nitrogen-containing treated water 11 into the reaction tank 1 in an upflow manner and bringing it into contact with the carrier 4 on which the anaerobic ammonia oxidizing bacteria are fixed.

The reaction tank 1 is provided with a water flow control member 5 mainly composed of Al ₂ O ₃ , and the carrier 4 on which the anaerobic ammonia oxidizing bacteria are fixed is held downstream of the water flow control member 5 . The water flow control member 5 is granular, and a plurality of granular water flow control members 5 are filled in the reaction tank 1 to form a layer. The water flow control member 5 functions as a flow straightening material, and when the water 11 to be treated passes through the water flow control member 5, the water to be treated is easily contacted uniformly with the carrier 4 on which the anaerobic ammonia oxidizing bacteria are fixed. Can be enhanced. Since the water flow control member 5 is made of a material containing Al ₂ O ₃ as a main component, the adhesion of bacterial cells is suppressed, and it becomes possible to stably exhibit the function as a rectifying material over a long period of time.

  Hereinafter, the present invention will be described in more detail by way of examples, but the scope of the present invention is not limited thereto.

Example 1
Anaerobic ammonia oxidation treatment was performed using a water treatment apparatus as shown in FIG. Sewage return water was used as the water to be treated, and the total nitrogen concentration of the water to be treated was an average of 669 mg-N / L, and the pH was an average of 7.6. The reaction tank was an upflow type, and alumina balls (particle diameter 5 to 8 mm) were filled as a flow straightening material on the side of the water supply portion to form a layer. On the downstream side of the rectifying material, anaerobic ammonia oxidizing bacteria were fixed to the carbide carrier and held in the reaction tank. The isoelectric point of the alumina ball is about pH 7.4 to 9.5. The water to be treated was introduced into the reaction tank at an empty velocity of about 10 m / day, and part of the treated water was mixed with the water to be treated and returned to the reaction tank. After the treatment for 150 days, the inside of the reaction vessel was checked. As a result, almost no cells were attached to the surface of the alumina ball.

Comparative Example 1
The process was performed in the same manner as in Example 1 except that glass balls (particle diameter 13 mm) were used as the flow control material. The glass ball is made of general glass composed of silicate, and the isoelectric point is about pH 2. After the treatment for 150 days, the inside of the reaction vessel was checked. As a result, the cells were attached to the entire surface of the glass ball, and the flow path between the glass balls was blocked. In addition, the anaerobic ammonia oxidation treatment performance was lower than that in Example 1, and it was necessary to reduce the amount of water to be treated introduced into the reaction tank as compared to Example 1.

Comparative example 2
The treatment was performed in the same manner as in Example 1 except that a shell was used as the flow control material. The shells are mainly composed of inorganic salts containing calcium silicate as a main component. After the treatment for 150 days, the inside of the reaction tank was confirmed. As a result, the cells were attached to a part of the surface of the shell, and the flow path between the shells was blocked. In addition, the anaerobic ammonia oxidation treatment performance was lower than that in Example 1, and it was necessary to reduce the amount of water to be treated introduced into the reaction tank as compared to Example 1.

  The present invention is used for treating wastewater from sewage, human waste, process wastewater generated along with sewage treatment and human waste treatment, factory wastewater generated from food factories, chemical factories etc., livestock manure, livestock waste, etc. Can.

1: Reaction tank 2: Supply part 3: Discharge part 4: Anaerobic ammonia oxidation bacteria fixed carrier 5: Water flow control member (Rectifying material)

Claims (7)

It has a reaction tank that brings the nitrogen-containing treated water into contact with anaerobic ammonia-oxidizing bacteria to carry out the anaerobic ammonia oxidation reaction,
A water treatment apparatus characterized in that a water flow control member containing Al ₂ O ₃ at a content of 85% by mass or more is provided in the reaction tank.   The water treatment apparatus according to claim 1, wherein the anaerobic ammonia oxidizing bacteria are held downstream of the water flow control member in the reaction tank.   The water treatment apparatus according to claim 2, wherein the reaction tank is an upflow type.   The anaerobic ammonia oxidizing bacterium is fixed to a carrier and held in the reaction vessel, or granulated and held in the reaction vessel according to any one of claims 1 to 3. Water treatment equipment.   The water treatment apparatus according to any one of claims 1 to 4, wherein the water flow control member is granular, and a plurality of granular water flow control members are filled in the reaction tank to form a layer. A water treatment method wherein an ammonia-oxidizing reaction is carried out by bringing nitrogen-containing treated water into contact with anaerobic ammonia-oxidizing bacteria,
A water treatment method comprising controlling the flow of water to be treated by bringing the water to be treated into contact with a water flow control member containing Al ₂ O ₃ at a content of 85% by mass or more .   The water treatment method according to claim 6, wherein the water to be treated is brought into contact with the anaerobic ammonia oxidizing bacteria after being brought into contact with the water flow control member.