JP6919304B2 - Ammonia nitrogen-containing wastewater denitrification treatment equipment and denitrification treatment method - Google Patents

Description

The present invention is a batch (SBR) one-tank type ANAMMOX process that contains ammoniacal nitrogen-containing wastewater, especially high concentrations of ammoniacal nitrogen, as well as biodegradable organic components (BOD components) and suspended solids (BOD components). The present invention relates to a method for solving problems caused by BOD and SS in raw water when treating wastewater containing both or either of SS), specifically, a dehydrated filtrate of methane fermentation digestive juice. Here, the one-tank type ANAMMOX process refers to a wastewater treatment process in which ammonia nitrogen is nitrite-denitrite and denitrified in the same tank by a mixed sludge of ammonia-oxidizing bacteria and ANAMMOX bacteria to remove nitrogen.

As a denitrification process for ammoniacal nitrogen-containing wastewater, ammonia nitrogen and nitrite are used by using ANAMMOX bacteria, which are independent nutrient microorganisms that use ammoniacal nitrogen as an electron donor and nitrite nitrogen as an electron acceptor. The ANAMMOX process, which reacts with nitrogen to denitrify, is known.

Conventionally, the wastewater treatment process using the ANAMMOX reaction has been carried out in a two-tank type in which a nitrite type nitrification tank and an ANAMMOX denitrification tank are provided and the treatment is performed in the order of nitrite formation → ANAMMOX reaction, but in recent years, ammonia oxidation has been carried out. A one-tank type ANAMMOX process has been developed in which nitrite formation and ANAMMOX reaction are carried out in one tank using sludge in which bacteria and ANAMMOX bacteria coexist (Patent Document 1).
Further, as a granule sludge useful for a one-tank type ANAMMOX process, a biofilm double structure in which the surface of a primary biofilm obtained by self-granulating ANAMMOX bacteria is covered with ammonia-oxidizing bacteria has been proposed (Patent Document). 2).

The one-tank type ANAMMOX process can be processed in both batch type (SBR) (Patent Document 3) and continuous type (Patent Document 4) reaction tanks, but a solid-liquid separation device is not required and the device structure is simple. The SBR type reaction tank is often used.

When the BOD component flows into the SBR type one-tank type ANAMMOX reaction tank,
(1) Competition by nitrite nitrogen between ANAMMOX bacteria and dependent nutrient denitrifying bacteria (2) Oxygen competition between ammonia oxidizing bacteria and dependent feeding denitrifying bacteria, resulting in ammonia oxidizing bacteria in sludge There is a problem that the proportion of ANAMMOX bacteria decreases and the quality of treated water deteriorates.

Therefore, in the ANAMMOX process, it has been proposed to perform activated sludge treatment as a pretreatment to remove the BOD of the inhibiting factor in advance when the raw water contains BOD (Patent Document 5).

However, this method has a drawback that the installation space of the pretreatment device is excessive because a settling basin is required after the BOD oxidation tank using activated sludge, and the merit of space saving of the ANAMMOX process is lost. ..
Another problem is that it is difficult to control the amount of sludge extracted and returned in the settling basin. For example, when the amount of sludge extracted is insufficient and the sludge residence time (SRT) becomes long, nitrifying bacteria grow in the sludge and ammoniacal nitrogen is oxidized to nitrate nitrogen. In this case, the substrate of the ANAMMOX bacteria in the subsequent stage is insufficient, the activity of the ANAMMOX reaction is greatly reduced, and the water quality of the treated water is deteriorated. On the contrary, when the SRT is shortened and the sludge concentration is lowered, the BOD sludge load becomes large and the filamentous fungi dominate in the activated sludge, resulting in deterioration of sludge sedimentation (bulking) and in the sedimentation basin. A large amount of SS may flow into the ANAMMOX reaction vessel, causing a solid-liquid separation failure.

In the ANAMMOX process, when suspended solids (SS) are contained in the raw water, SS with a high sedimentation rate accumulates in the ANAMMOX reaction tank, which changes the apparent sludge growth rate and makes sludge management difficult. There is also the problem. To solve this problem, if a physicochemical treatment means such as a coagulation / settling tank is provided in front of the ANAMMOX reaction tank, it is necessary to add a pH adjuster, an inorganic coagulant, and a polymer (polymer coagulant), and running. The cost is high. In particular, in raw water having a high inorganic carbon (IC) concentration such as a dehydrated filtrate of methane fermentation digestive juice, the coagulation effect of the coagulant is low, and it is necessary to add a large amount of the coagulant.

For these reasons, in the conventional one-tank type ANAMMOX process, there has been a demand for a space-saving and easy-to-manage denitrification treatment technique even when the raw water contains BOD, which is an inhibitor of the ANAMMOX reaction. Further, it has been required to remove SS in raw water by an inexpensive method.

Special Table 2001-506535 Gazette Japanese Patent No. 461374 Japanese Patent No. 5347221 Japanese Unexamined Patent Publication No. 2010-22193 Japanese Patent No. 4649911

The present invention solves the above-mentioned conventional problems, and in the denitrification treatment of ammoniacal nitrogen-containing wastewater by the SBR type one-tank type ANAMMOX process, even if the raw water contains BOD or SS which is an inhibitory factor of the ANAMMOX reaction, it can be saved. It is an object of the present invention to provide a denitrification treatment device and a treatment method for ammoniacal nitrogen-containing wastewater, which can remove BOD by a space and easy-to-manage method and can remove SS in raw water at low cost. ..

As a result of repeated studies to solve the above problems, the present inventors have provided an SBR-type aerobic biological treatment tank in front of the SBR-type one-tank type ANAMMOX reaction tank, and this SBR-type aerobic biological treatment. It has been found that the above problems can be solved by removing BOD and SS in raw water in a tank.
That is, the gist of the present invention is as follows.

[1] A batch-type one-tank type ANAMMOX reaction tank containing mixed sludge of ammonia-oxidizing bacteria and ANAMMOX bacteria, a batch-type aerobic biological treatment tank provided in front of the ANAMMOX reaction tank, and an ammonia nitrogen-containing It has means for introducing wastewater into the aerobic biological treatment tank as raw water, means for introducing the treated water from the aerobic biological treatment tank into the ANAMMOX reaction tank, and means for discharging the treated water from the ANAMMOX reaction tank. A denitrification treatment device for ammoniacal nitrogen-containing wastewater.

[2] In [1], a denitrification treatment apparatus for ammoniacal nitrogen-containing wastewater, which comprises a means for drawing out SS in the raw water that has settled in the aerobic organism treatment tank.

[3] In [1] or [2], a relay tank is provided between the aerobic biological treatment tank and the ANAMMOX reaction tank, and the treated water in the aerobic biological treatment tank passes through the relay tank and the ANAMMOX. A denitrification treatment device for ammoniacal nitrogen-containing wastewater, which is characterized by being introduced into a reaction vessel.

[4] In any one of [1] to [3], a nitrification tank, a denitrification tank and a reaeration tank, a circulating denitrification / nitrification tank, or a denitrification tank is provided after the ANAMMOX reaction tank. A denitrification treatment device for ammonia-containing nitrogen-containing wastewater.

[5] In any of [1] to [4], the ammonia nitrogen-containing tank is characterized by having a coagulation / settling tank, a coagulation / pressurized flotation separation tank, or a settling tank after the ANAMMOX reaction tank. Wastewater denitrification treatment equipment.

[6] In any one of [1] to [5], a denitrification treatment apparatus for ammonia nitrogen-containing wastewater, wherein the raw water is a dehydrated filtrate of an anaerobic digestive juice.

[7] In a method of batch denitrification using a one-tank type ANAMMOX reaction tank containing a mixed sludge of ammonia-oxidizing bacteria and ANAMMOX bacteria using ammonia nitrogen-containing wastewater as raw water, in the pre-stage of the ANAMMOX reaction tank. A method for denitrifying ammonia nitrogen-containing wastewater, which comprises providing a batch-type aerobic biological treatment tank, treating the raw water in the aerobic biological treatment tank, and then treating the raw water in the ANAMMOX reaction tank.

[8] In [7], in the aerobic biological treatment tank, the SS in the raw water is settled and pulled out to remove the SS in the raw water, which is characterized by denitrification of the ammoniacal nitrogen-containing wastewater. Processing method.

[9] In [7] or [8], a relay tank is provided between the aerobic biological treatment tank and the ANAMMOX reaction tank, and the treated water of the aerobic biological treatment tank is passed through the relay tank to the ANAMMOX. A method for denitrifying ammonia-based nitrogen-containing wastewater, which is characterized by being introduced into a reaction vessel.

[10] In any of [7] to [9], a nitrification tank, a denitrification tank and a reaeration tank, a circulation type denitrification / nitrification tank, or a denitrification tank is provided after the ANAMMOX reaction tank. A method for denitrifying ammonia-based nitrogen-containing wastewater, which further denitrifies the treated water in the ANAMMOX reaction tank.

[11] In any of [7] to [10], a coagulation / settling tank, a coagulation / pressurized flotation tank, or a settling tank is provided after the ANAMMOX reaction tank, and the treated water in the ANAMMOX reaction tank is coagulated. A method for denitrifying ammonia nitrogen-containing wastewater, which comprises precipitation, aggregation / pressure flotation, or precipitation treatment.

[12] The method for denitrifying ammonia nitrogen-containing wastewater according to any one of [7] to [11], wherein the raw water is a dehydrated filtrate of an anaerobic digestive juice.

According to the present invention, an SBR-type aerobic biological treatment tank is provided in front of the SBR-type one-tank type ANAMMOX reaction tank, and the BOD in the raw water is decomposed and removed in this aerobic biological treatment tank, and the SS derived from the raw water is decomposed and removed. Can be settled and removed.
The SBR type aerobic biological treatment tank does not require a settling basin, so it saves space, and there is no need to return sludge, and sludge extraction can be easily managed, which is caused by excess or deficiency of sludge extraction. Problems such as deterioration of water quality will be solved.

It is a system diagram which shows an example of embodiment of the denitrification treatment apparatus of the ammoniacal nitrogen-containing wastewater of this invention. It is a system diagram which shows another example of embodiment of the denitrification treatment apparatus of the ammoniacal nitrogen-containing wastewater of this invention. It is a system diagram which shows another example of embodiment of the denitrification treatment apparatus of the ammoniacal nitrogen-containing wastewater of this invention. It is a system diagram which shows another example of embodiment of the denitrification treatment apparatus of the ammoniacal nitrogen-containing wastewater of this invention. It is a graph which shows the time-dependent change _{of the soluble COD Cr} concentration in the BOD oxidation tank in Example 1.

Embodiments of the present invention will be described in detail below.

In the present invention, an ANAMMOX reaction tank (hereinafter, may be referred to as a "one-tank type ANAMMOX tank" or "ANAMMOX tank") containing a mixed sludge of ammonia-oxidizing bacteria and ANAMMOX bacteria using ammonia nitrogen-containing wastewater as raw water. When denitrifying with the SBR method, an SBR type aerobic biological treatment tank (hereinafter, may be referred to as "BOD oxidation tank") is provided in front of the reaction tank, and the BOD in the raw water is oxidized by this BOD. After oxidative decomposition in the tank and sedimentation and separation of SS in the raw water to remove it, it is introduced into a one-tank type ANAMMOX tank and subjected to ANAMMOX treatment.

[ANAMMOX process]
The ammoniacal nitrogen-containing wastewater to be treated in the present invention may be a liquid containing ammoniacal nitrogen or organic nitrogen that can be treated with nitrogen by contacting with a granule containing ammonia-oxidizing bacteria and ANAMMOX bacteria. Is particularly effective against high concentrations of ammoniacal nitrogen and wastewater containing BOD and / or SS. Specific examples of such wastewater include a dehydrated filtrate of an aerobic digestive juice (methane fermentation digestive juice). The dehydrated filtrate of the anaerobic digestive juice generally contains 500 mg-N / L or more of ammoniacal nitrogen, and has a BOD and SS of 1,000 mg / L or more depending on the operating conditions of the methane fermenter and the dehydrator. May contain. In addition, even if the SS or BOD concentration in the raw water is low, if the raw water contains a polymer or a bactericide, it inhibits ammonia-oxidizing bacteria or ANAMMOX bacteria and deteriorates the water quality of the treated water. The method of the present invention may be applied even in such a case.

The ammonia-oxidizing bacteria used for nitrite formation of ammoniacal nitrogen in the present invention are bacteria conventionally used for nitrite formation of ammoniacal nitrogen, and nitrite by oxidizing ammoniacal nitrogen under aerobic conditions. It is a bacterium that converts to sex nitrogen.

The ANAMMOX bacterium used for denitrification in the present invention is a bacterium belonging to Planctomycetes, which is a denitrifying bacterium that reacts ammoniacal nitrogen and nitrite nitrogen in an anaerobic atmosphere and directly converts them into nitrogen gas. Unlike the heterotrophic denitrifying bacterium used for conventional denitrification, such ANAMMOX bacterium is an autotrophic bacterium. Does not require the addition of nutrient sources. Further, since ANAMMOX bacteria react ammonia nitrogen and nitrite nitrogen and directly convert them into nitrogen gas, ammonia nitrogen and nitrite nitrogen can be removed at the same time, and harmful by-products are not produced.

In the present invention, the mixed sludge of ammonia-oxidizing bacteria and ANAMMOX bacteria used in the ANAMMOX tank is, in particular, a biological double structure in which the surface of the primary biofilm of the self-granulated product of ANAMMOX bacteria is covered with ammonia-oxidizing bacteria. Is preferable.
Hereinafter, the treated sludge suitable for the present invention will be described.

The self-granulation of ANAMMOX bacteria can be formed by self-granulation of ANAMMOX bacteria according to a conventional method.
In the case of self-granulation of ANAMMOX bacteria, since it takes a long time for ANAMMOX bacteria to self-granulate, a core substance is added to form a biofilm of ANAMMOX bacteria around the nucleus. In this case, as the self-granulation of the microorganism used as the nucleus, the self-granulation of the anaerobic microorganism of the methanogen granule can be used. Methanogen self-granulated products are produced in a methane fermenter in which methane fermentation is carried out by the UASB (Upflow Anaerobic Sludge Blanket) method or the EGSB (Expanded Granule Sludge Bed) method. The one used can be applied. These self-granulated products can be used as they are or as crushed products thereof. ANAMMOX bacteria are likely to adhere to such microbial self-granulations, reducing the time required to form self-granulations. It is also more economical than using abiotic materials as nuclei.

The shape of the primary biofilm, which is a self-granulated product of ANAMMOX bacteria, is not particularly limited, and is granular (spherical, cubic, or other irregular shape), string-shaped, rod-shaped or other long-shaped, film-shaped or other flat surface. A wide variety of shapes such as shapes can be adopted, and the size is arbitrary, but from the viewpoint of handleability, formation efficiency of biofilm double structure, etc., the size should be as follows. Is preferable.
Granular: 3 to 20 mm in diameter or side length
In the case of long shape: length 3 to 2000 mm, thickness 0.1 to 5 mmφ
In the case of flat surface: No area limit, thickness 0.1 to 5 mm

In order to cover the surface of such a primary biofilm with ammonia-oxidizing bacteria to form a biological double structure, for example, the primary biofilm is placed in a nitrification tank and held so as not to flow out of the nitrification tank. do. When there is a risk of outflow only by putting the primary biofilm into the nitrification tank, it is preferable to provide a screen in the nitrification tank so that the primary biofilm does not flow out. Alternatively, the primary biofilm may be discharged together with the nitrification solution, introduced into a settling tank for solid-liquid separation, and the separated primary biofilm may be returned to the nitrification tank.

The amount of the primary biofilm charged into the nitrification tank is appropriately determined according to the ammonia concentration in the raw water, the load on the nitrification tank such as the amount of treated water, etc., but is usually 500 to 5000 mg / L as MLSS. It is preferable to put in as such.

By putting the primary biofilm into the nitrification tank and holding it, a biofilm of ammonia-oxidizing bacteria is formed on the surface of the primary biofilm, and the primary biofilm of ANAMMOX bacteria suitable for the ANAMMOX process is made of ammonia-oxidizing bacteria. A covered biofilm double structure can be obtained.

[Operation of batch type (SBR)]
In the present invention, both the BOD oxidation tank and the ANAMMOX tank are operated by the SBR method. The operation method is raw water introduction process → aeration process → sludge sedimentation process → sludge extraction process → treated water discharge process, or raw water introduction and aeration process (raw water introduction and aeration are performed at the same time) → (further aeration process if necessary → ) Any operation method of sludge sedimentation step → sludge extraction step → treated water discharge step may be used.
In the ANAMMOX tank, the sludge extraction step does not necessarily have to be carried out, but is carried out as needed.

If the raw water is microbially inhibitory or has a high pH, the Fill & Draw method, in which the substrate is flowed in at once at the start of the batch, increases the concentration and pH of the inhibitor in the ANAMMOX tank, which may inhibit microbial activity. , Fed-Batch formula is preferably selected. In this case, as will be described later, it is desirable to install a relay tank between the BOD oxidation tank and the ANAMMOX tank.
The amount of water discharged from the tank can be appropriately set in the range of 10 to 80% of the water level at the time of full water in both the BOD oxidation tank and the ANAMMOX tank.

If the BOD concentration of raw water fluctuates, a screen is installed at the outlet of the BOD oxidation tank and a small amount (5 to 20%) of microbial carrier is added to cope with a sudden increase in BOD concentration. be able to.

[Treatment in BOD oxidation tank]
<Treatment with floating sludge (floating bacteria) that does not form flocs>
When flocs are formed by bacteria in the BOD oxidation tank, the necessary bacteria are extracted as SS and it becomes difficult to retain the necessary bacteria in the tank. In this case, if the extraction of SS is controlled so that the flocs remain to some extent, the nitrifying bacteria will grow on the flocs as a scaffold over time, and the ammoniacal nitrogen in the raw water will be oxidized to nitrate nitrogen. Inappropriate. Therefore, it is preferable that the BOD oxidation tank is a floating type, and therefore, the operating conditions of the BOD oxidation tank are set to a short SRT, a transient type, and a high BOD sludge load in addition to the batch type (SBR). It is preferable to promote the dominance of airborne bacteria for treatment.

Therefore, in the SBR type BOD oxide tank according to the present invention, it is preferable to perform the following operations.
(1) In the sludge sedimentation step, the sedimented sludge is withdrawn so that the SRT is 5 days or less, preferably 3 days or less, for example, 1 to 2 days. If the SRT is longer than the lower limit below, nitrifying bacteria are likely to grow. The sludge may be extracted intermittently or continuously.
(2) The BOD oxidation tank will be a transient type, and the drawn sludge will not be returned or supplied. When the sludge is returned, nitrifying bacteria are likely to grow.
(3) The BOD sludge load of the BOD oxidation tank is 2 to 20 kg-BOD / kg-SS / day. If the BOD sludge load in the BOD oxidation tank is lower than the above lower limit, flocs are likely to be formed, and if it is higher than the above upper limit, the treatment tends to be insufficient.
(4) The time of the sludge settling step in the BOD oxidation tank is set to 15 minutes to 2 hours. If the time of the precipitation step is less than 15 minutes, SS derived from raw water cannot be sufficiently removed, while if about 2 hours are spent, most of SS derived from raw water is removed.
That is, SS having a faster settling speed than the granule (the settling speed of the granule is slow, 1 to 5 m / hr) that is statically settled and separated in the sludge settling step of the ANAMMOX tank is not supplied from the BOD oxidation tank to the ANAMMOX tank. Therefore, it is necessary to separate and remove SS having a high sedimentation rate in the BOD oxidation tank. Although it depends on the water level in the tank to which the water in the tank is drawn, the time of the precipitation step for that purpose is set as described above.

In this way, in the BOD oxidation tank, the sludge should not be returned as a transient type, the SRT should be 5 days or less, preferably 3 days or less, and the BOD sludge load should be operated at a high load of 2 kg-BOD / kg-SS / day or more. Therefore, it is preferable to suppress the formation of flocs and remove BOD by airborne bacteria.
Since the floating bacteria have a very slow sedimentation rate of 0.01 m / hr or less, they are not settled and removed in the sludge sedimentation step of the BOD oxidation tank, and flow into the ANAMMOX tank together with the treated water of the BOD oxidation tank. Similarly, since it is not removed in the sludge sedimentation step in the tank, it is discharged as treated water without accumulating in the tank.

<Omission of solid-liquid separation means associated with BOD oxidation>
In the conventional method, BOD is decomposed by activated sludge forming flocs in a BOD oxidation tank, and solid-liquid separation is performed in a settling basin.
On the other hand, in the present invention, the sludge is not returned and the SRT is set short to dominate the floating bacteria and remove the BOD. Floating bacteria flow into the ANAMMOX tank together with the treated water in the BOD oxidation tank, but because the sedimentation rate is very slow, the suspended bacteria do not settle and accumulate in the sludge sedimentation step of the ANAMMOX tank, and the treated water in the ANAMMOX tank (ANAMMOX treated water). ) And leak. In the present invention, this eliminates the need to provide a settling basin between the BOD oxidation tank and the ANAMMOX tank, and can save space as compared with the prior art.

<Selective removal of SS derived from raw water>
In the conventional one-tank type ANAMMOX tank, when SS derived from raw water flows in, there is a problem that SS having a sedimentation rate equivalent to that of ANAMMOX granules precipitates in the sludge sedimentation step and accumulates in the tank.
In the present invention, in the sludge sedimentation step of the BOD oxidation tank, SS having a high sedimentation rate can be sedimented and extracted, and SS derived from raw water can be suppressed from flowing into and accumulating in the ANAMMOX tank.
As described above, when SS is contained in the raw water, in the present invention, the sludge sedimentation step of the BOD oxidation tank is used to settle and extract the SS derived from the raw water having a high sedimentation rate such as accumulating in the ANAMMOX tank. , SS derived from raw water can be prevented from accumulating in the ANAMMOX tank. In the ANAMMOX tank, granules having a sedimentation speed of about 1 to 5 m / hr are usually precipitated and maintained in the tank. It is preferable to determine the time of the process.
The extraction of SS settled in the BOD oxidation tank does not need to be performed at a predetermined frequency, but the SRT is operated in 5 days or less, preferably 3 days or less in order to suppress the growth of nitrifying bacteria.

[Treatment in ANAMMOX tank]
The reaction formulas of the nitrite formation of ammoniacal nitrogen and the ANAMMOX reaction are as shown in the following formulas 1 and 2. The one-tank type ANAMMOX reaction in which Formulas 1 and 2 are summarized is as shown in Formula 3 below. From Equation 3, in the one-tank type ANAMMOX reaction, the pH decreases with the removal of ammonia, but when high pH raw water is introduced, a pH adjuster (acid, etc.) is added as necessary. It is preferable to adjust the pH to a pH range (pH 6.7 to 8.3) that does not inhibit ANAMMOX bacteria.
<Nitriteization of ammoniacal nitrogen>
1.0NH ₄ ⁺ + _{1.5O 2} → 1.0NO ₂ + H ₂ O + ^{2.0H +} Equation 1
<ANAMMOX reaction>
^{_{1.0NH 4 + + 1.32NO 2 - +}} 0.066HCO 3 - →
^{_{1.02N 2 + 0.26NO 3 - + 0.066CH}} 2 O 0.5 N 0.15
+ 2.03H ₂ O + 0.13OH ^- Equation 2
<Denitrification reaction by one-tank type ANAMMOX reaction>
1.0NH ₄ ⁺ + 0.65O ₂ →
^{_{0.44N 2 + 0.11NO 3 - + 1.14H}} + + 1.43H 2 O Formula 3

Further, in the ANAMMOX tank, as described above, the airborne bacteria flowing from the BOD oxidation tank and the SS having a slow sedimentation rate are contained in the treated water from the ANAMMOX tank without settling together with the ANAMMOX sludge in the sludge sedimentation step of the ANAMMOX tank. It is preferable to set the time of the sludge sedimentation step in the ANAMMOX tank to be 15 minutes to 2 hours (however, the time is the same as or shorter than the time of the sludge sedimentation step in the BOD oxidation tank) so as to flow out.

[Post-processing]
As described above, the reaction formula of the ANAMMOX process is as shown in Formula 3, and 0.11 mol of nitrate nitrogen is produced with respect to 1 mol of ammonia nitrogen in the raw water, so that nitrate nitrogen remains in the treated water. If this concentration does not meet the required criteria for wastewater treatment, a nitrification-denitrification-re-aeration process, a denitrification-nitrification process (circulation method), or a denitrification process is performed as a finishing treatment in the subsequent stage of the ANAMMOX tank. It is preferable to remove the residual nitrate nitrogen by providing the mixture.

In addition, the treated water in the ANAMMOX tank contains airborne bacteria and SS with a slow sedimentation rate that could not be removed by the BOD oxidation tank. In this case as well, if the required standards for wastewater treatment are not met, SS is removed by providing a solid-liquid separation means (coagulation sedimentation process, coagulation pressure flotation process, or sedimentation process) in the subsequent stage of the ANAMMOX tank. May be good.

[Specific tank configuration]
The specific tank configuration of the denitrification treatment apparatus for ammoniacal nitrogen-containing wastewater of the present invention will be described below with reference to FIGS. 1 to 4. FIGS. 1 to 4 are system diagrams showing an example of an embodiment of the denitrification treatment apparatus for ammonia nitrogen-containing wastewater of the present invention, and members having the same function are designated by the same reference numerals. In each case, the aeration piping and blower for aeration are not shown.

FIG. 1 shows a denitrification treatment device for ammonia-based nitrogen-containing wastewater in which a BOD oxidation tank 1 and an ANAMMOX tank 2 are connected in series, and raw water is introduced into the BOD oxidation tank 1 from a pipe 11 and treated by an SBS method. NS.
The SS derived from the raw water that has settled in the sludge settling step of the BOD oxidation tank 1 is pulled out from the pipe 12. The treated water in the BOD oxidation tank 1 contains ammoniacal nitrogen, airborne bacteria in the BOD oxidation tank 1, and SS that did not settle in the precipitation step, and this treated water is introduced into the ANAMMOX tank 2 from the pipe 13. , SBR formula ANAMMOX treatment removes ammoniacal nitrogen, and the treated water is discharged from the pipe 14.
The treated water in the ANAMMOX tank 2 contains airborne bacteria from the BOD oxidation tank 1 and SS that did not settle in the sedimentation step of the ANAMMOX tank 2.

As mentioned above, if the raw water is microbially inhibitory or has a high pH, the Fill & Draw method, in which the substrate flows in at once at the start of the batch, increases the concentration and pH of the inhibitor in the tank and inhibits microbial activity. Therefore, it is preferable to select the Fed-Batch formula. In this case, as shown in FIG. 2, it is desirable to install the relay tank 3 between the BOD oxidation tank 1 and the ANAMMOX tank 2.
In FIG. 2, a relay tank 3 is provided between the BOD oxidation tank 1 and the ANAMMOX tank 2, and the treated water of the BOD oxidation tank 1 from the pipe 13 is introduced into the ANAMMOX tank 2 from the pipe 15 via the relay tank 3. The configuration is the same as that of the denitrification treatment apparatus shown in FIG.

When the relay tank 3 is provided in this way, the operation cycle of each tank can be as shown in Table 1 below, and the aeration time in each tank can be secured for a long time.

That is, if there is no relay tank, the drainage time from the BOD oxidation tank (treated water discharge step) = the inflow time into the ANAMMOX tank (raw water introduction step). The drainage time in the oxidation tank is also long, and the aeration time in the BOD oxidation tank cannot be long. In this case, by providing the relay tank, the drainage time from the BOD oxidation tank = the inflow time to the relay tank, the inflow time to the ANAMMOX tank = the drainage time from the relay tank, and the inflow time to the ANAMMOX tank can be made longer. Since the drainage time from the BOD oxidation tank can be set regardless of this time, a sufficient aeration time in the BOD oxidation tank can be secured.

As mentioned above, nitrate nitrogen remains in the ANAMMOX treated water, so if this concentration does not meet the required standards for wastewater treatment, nitrification-denitrification-reaeration is performed as a finishing treatment in the subsequent stage of the ANAMMOX tank. It is preferred to provide a process, denitrification-nitrification process (circulation method), or denitrification process to remove residual nitrate nitrogen.

FIG. 3A shows an apparatus in which a denitrification tank 4 is provided after the ANAMMOX tank 2, and FIG. 3B shows a nitrification tank 5A, a denitrification tank 5B, and a reaeration tank 5C after the ANAMMOX tank 2. An apparatus is shown, and FIG. 3 (c) shows an apparatus in which a circulation type denitrification / nitrification tank 6 is provided after the ANAMMOX tank 2.

In the apparatus of FIG. 3A, the ANAMMOX-treated water from the ANAMMOX tank 2 is supplied from the pipe 14 to the denitrification tank 4, and the nitrate nitrogen is converted into nitrogen gas by the anaerobic treatment and removed, and the denitrification treatment is performed. Water is discharged from the system through the pipe 16. In the apparatus of FIG. 3B, the ANAMMOX treated water from the ANAMMOX tank 2 is sequentially treated from the pipe 14 in the nitrification tank 5A, the denitrification tank 5B, and the reaeration tank 5C, and then discharged from the pipe 16 to the outside of the system. In the apparatus of FIG. 3C, the ANAMMOX treated water from the ANAMMOX tank 2 is introduced into the nitrification tank 6B from the pipe 17 via the denitrification tank 6A from the pipe 14, and a part of the treated water in the nitrification tank 6B is introduced from the pipe 18. By being circulated and treated in the denitrification tank 6A, nitrification and denitrification treatment of nitrogen in the ANAMMOX treated water is performed, and the treated water is discharged to the outside of the system from the pipe 16.

In either case, it is possible to obtain high-quality denitrified treated water from which nitrogen in the raw water has been highly removed.

4 (a) to 4 (c) show an apparatus provided with a settling tank 7, a coagulation tank 8 and a settling tank 7, or a coagulation / pressure flotation separation tank 9 for removing SS in ANAMMOX-treated water, respectively. After being treated in the denitrification tank 4, the ANAMMOX-treated water from the ANAMMOX tank 2 is introduced into the settling tank 7, the coagulation tank 8 and the settling tank 7, or the coagulation / pressure flotation separation tank 9, respectively, to remove SS. After the treatment, it is discharged to the outside of the system from the pipe 19.

The settling tank 7, the coagulation tank 8 and the settling tank 7, or the coagulation / pressure flotation separation tank 9 in FIGS. 4 (a) to 4 (c) may be provided directly after the ANAMMOX tank 2, and FIG. It may be provided after the re-aeration tank 5c in b), or may be provided after the nitrification tank 6B in FIG. 3 (c).
Further, in the apparatus shown in FIGS. 3 and 4, a relay tank 3 may be provided between the BOD oxidation tank 1 and the ANAMMOX tank 2 as in FIG. 2.

Hereinafter, the present invention will be described in more detail with reference to examples.

[Example 1]
_{Acetic acid and propionic acid should be added to COD Cr} 2,000 mg / L, and activated sludge should be added to SS 3,000 mg / L to the synthetic wastewater adjusted to ammonia nitrogen 1,800 mg / L. So, a simulated wastewater containing BOD and SS was prepared.
Using this simulated wastewater as raw water, it is treated with a test device of an SBR type BOD oxidation tank, and the treated water is treated with a laboratory test device of an SBR type one-tank type ANAMMOX tank to perform a simulated test of an embodiment of the present invention. rice field.

The volume of the BOD oxidation tank was 2 L, and the volume of the one-tank type ANAMMOX tank was 3 L. The water temperature of the device was set to 30 ° C. The pH was adjusted to 7.8 using a pH adjuster only in the one-tank type ANAMMOX tank. As seed sludge, activated sludge cultivated in synthetic effluent was put into the BOD oxidation tank so as to reach MLSS 1,000 mg / L, and in the ANAMMOX tank, a single-tank type ANAMMOX granule cultivated in synthetic effluent (the above-mentioned biological double). The structure) was charged so that the settling volume was 30% of the tank volume.

The amount of exchanged water per batch of the BOD oxidation tank was 1 L (50% of the tank volume). The SBR cycle consisted of a raw water introduction step of 5 min, an aeration step of 8.15 hr, a sludge sedimentation step of 15 min, a sludge extraction step of 3 min, and a treated water discharge step of 5 min. SRT is 3 days.
The treated water of the BOD oxidation tank was passed through the ANAMMOX tank, and the amount of exchanged water was 33% (1 L) of the tank volume. The SBR cycle was 5 min for the introduction step of the water to be treated, 8.4 hr for the aeration step, 15 min for the precipitation step, and 5 min for the discharge of the treated water (nitrogen load 1.5 kg-N / m ³ / day).
The number of batches was assumed to be 2.8 batches / day, and the BOD sludge load in the BOD oxidation tank was set to 5 kg-BOD / kg-SS / batch.

After operating the BOD oxidation tank for 30 days, the change in the concentration _{of soluble COD Cr in the BOD oxidation tank in one batch was measured.} The result is shown in FIG. As shown in FIG. 1, the soluble COD _Cr decreased with time and became 40 mg / L or less after 4 hours. As a result of analyzing the concentrations of acetic acid and propionic acid after the completion of one batch, the concentrations were below the lower limit of detection, respectively. The nitrogen concentration of the treated water in the BOD oxidation tank was 1,760 mg / L for ammonia nitrogen and 1 mg / L or less for nitrite nitrogen and nitrate nitrogen, so nitrification did not occur in the BOD oxidation tank. I understand. Further, in the BOD oxidation tank, SS having a high sedimentation rate was removed, and the SS of the treated water became 241 mg / L.

When the treated water in this BOD oxidation tank was passed through a one-tank type ANAMMOX tank for 30 days for treatment, the nitrogen concentration of the treated water (ANAMMOX treated water) was 0.9 mg / L of ammoniacal nitrogen and nitrite nitrogen. The ratio was 5.6 mg / L and nitrate nitrogen was 146 mg / L, and nitrogen was sufficiently removed. Moreover, the SV (sludge volume) at this time was 34%, and the accumulation of SS was hardly observed.
The test results of Example 1 are summarized in Table 2.

[Comparative Example 1]
In Example 1, a mock test was carried out in the same manner except that the BOD oxidation tank was omitted.
As a result, about 678 mg / L of ammoniacal nitrogen remained in the treated water (ANAMMOX treated water), and the nitrogen removal rate was as low as 59%.
It is considered that this is because the inflow of organic matter into the ANAMMOX tank caused competition due to oxygen between the ammonia-oxidizing bacteria and the heterotrophic denitrifying bacteria, and the ammonia oxidation rate decreased. In addition, the SV at this time was 63%, and it was confirmed that flocs different from those of ANAMMOX granules were accumulated. This was considered to be a heterotrophic bacterium grown by SS or BOD derived from raw water.
The test results of Comparative Example 1 are summarized in Table 2.

1 BOD Oxidation Tank 2 ANAMMOX Tank 3 Relay Tank 4, 5B, 6A Denitrification Tank 5A, 6B Nitrification Tank 5C Reaeration Tank 7 Sedimentation Tank 8 Coagulation Tank 9 Coagulation / Dissolved Float Separation Tank

Claims (10)

A batch-type one-tank type ANAMMOX reaction tank containing mixed sludge of ammonia-oxidizing bacteria and ANAMMOX bacteria,
A batch-type aerobic biological treatment tank provided in front of the ANAMMOX reaction tank, and a batch-type aerobic biological treatment tank.
A means for introducing ammonia nitrogen-containing wastewater as raw water into the aerobic biological treatment tank,
A means for introducing the treated water from the aerobic biological treatment tank into the ANAMMOX reaction tank, and
A denitrification treatment device for ammoniacal nitrogen-containing wastewater having a means for discharging treated water from the ANAMMOX reaction tank.
Ammonia characterized by having a relay tank between the aerobic biological treatment tank and the ANAMMOX reaction tank, and the treated water of the aerobic biological treatment tank is introduced into the ANAMMOX reaction tank via the relay tank. A denitrification treatment device for wastewater containing sexual nitrogen. The denitrification treatment apparatus for ammonia nitrogen-containing wastewater according to claim 1, wherein the SS is extracted from the raw water that has settled in the aerobic biological treatment tank. The ammoniacal nitrogen-containing wastewater according to claim 1 or 2 , wherein a nitrification tank, a denitrification tank and a reaeration tank, a circulating denitrification / nitrification tank, or a denitrification tank is provided after the ANAMMOX reaction tank. Denitrification processing equipment. The removal of ammoniacal nitrogen-containing wastewater according to any one of claims 1 to 3 , wherein a coagulation / settling tank, a coagulation / pressurized flotation separation tank, or a settling tank is provided after the ANAMMOX reaction tank. Nitrogen treatment equipment. The device for denitrifying ammonia-based nitrogen-containing wastewater according to any one of claims 1 to 4 , wherein the raw water is a dehydrated filtrate of an anaerobic digestive juice. In a method of batch denitrification using a one-tank type ANAMMOX reaction tank containing mixed sludge of ammonia-oxidizing bacteria and ANAMMOX bacteria using ammonia nitrogen-containing wastewater as raw water.
A batch-type aerobic biological treatment tank was provided in front of the ANAMMOX reaction tank.
A method for denitrifying ammonia nitrogen-containing wastewater, which treats the raw water in the aerobic biological treatment tank and then treats it in the ANAMMOX reaction tank.
Ammonia-based, characterized in that a relay tank is provided between the aerobic biological treatment tank and the ANAMMOX reaction tank, and the treated water of the aerobic biological treatment tank is introduced into the ANAMMOX reaction tank via the relay tank. Denitrification treatment method for nitrogen-containing wastewater. The method for denitrifying ammonia nitrogen-containing wastewater according to claim 6 , wherein the SS in the raw water is removed by sedimenting and pulling out the SS in the aerobic biological treatment tank. In claim 6 or 7 , a nitrification tank, a denitrification tank and a reaeration tank, a circulating denitrification / nitrification tank, or a denitrification tank is provided after the ANAMMOX reaction tank, and the treated water in the ANAMMOX reaction tank is further added. A method for denitrifying wastewater containing ammoniacal nitrogen, which comprises denitrifying. In any one of claims 6 to 8 , a coagulation / settling tank, a coagulation / pressurized flotation tank, or a settling tank is provided after the ANAMMOX reaction tank, and the treated water in the ANAMMOX reaction tank is agglomerated / settled and agglomerated. -A method for denitrifying ammonia-based nitrogen-containing wastewater, which is characterized by pressure flotation or precipitation treatment. The method for denitrifying ammonia nitrogen-containing wastewater according to any one of claims 6 to 9 , wherein the raw water is a dehydrated filtrate of an anaerobic digestive juice.

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