JP5951531B2 - Wastewater treatment equipment - Google Patents

Description

Embodiments of the present invention, for example, relates to a waste water treatment equipment for processing sewage and industrial wastewater.

  Biological treatment is often used in the treatment of wastewater containing organic matter such as sewage and industrial wastewater. Biological treatment can be classified into anaerobic treatment using anaerobic microorganisms and aerobic treatment with aerobic microorganisms.

  Anaerobic treatment has advantages such as low supply of oxygen because it does not require oxygen supply, low generation of sludge, and recovery of biogas mainly composed of flammable methane gas. Compared with aerobic treatment, the organic substance removal performance is poor, and as it is, it is difficult to discharge it into a river or the like. In addition, when sulfur components such as sulfuric acid are contained in the water to be treated, hydrogen sulfide is generated by the action of sulfate-reducing bacteria, one of anaerobic microorganisms, and the hydrogen sulfide is mixed into biogas. In order to effectively use the gas, it is necessary to perform some kind of desulfurization treatment.

  On the other hand, aerobic treatment has the merit that it can obtain the quality of treated water that can be discharged into rivers. However, it is necessary to supply oxygen for treatment with aerobic microorganisms, and power for that is required. It becomes. In addition, when treatment with aerobic microorganisms is performed, the amount of sludge generated is greater than that of anaerobic microorganisms.

  Therefore, a water treatment process has been devised that performs anaerobic treatment on the upstream side and aerobic treatment on the downstream side, and has been put into practical use as a factory wastewater treatment facility for the purpose of organic matter removal.

  However, the combination of a simple anaerobic treatment tank and an aerobic treatment tank cannot remove nitrogen, which is required to be removed as a countermeasure for eutrophication, so nitrogen can be removed as a subsequent aerobic treatment. A treatment using a circulatory nitrification denitrification method is also being adopted.

In FIG. 5, an example of the conventional waste water treatment process which provided the circulation type nitrification denitrification processing tank in the back | latter stage is shown. In this example, the water to be treated flows into the anaerobic treatment tank 1, where organic substances are removed, and then the denitrification tank 14 and the aerobic tank 2 are sent in this order. Nitrogen components in the water to be treated are oxidized to nitrate or nitrite nitrogen in the aerobic tank 2, sent to the denitrification tank 14 by the nitrification liquid circulation pump 13, and reduced to nitrogen gas by the action of denitrifying bacteria. , Discharged outside the system. The reaction formula for denitrifying bacteria is shown below.
5CH ₃ COO ⁻ + 8NO ₃ ⁻ + 8H ⁺ → 5CO ₂ + 5HCO ₃ ⁻ + 4N ₂ + 4H ₂ O

  In the above reaction, in order to reduce nitrate nitrogen, an organic substance is required, and it is necessary to adjust the BOD / N ratio to be 2.8 or more. Depending on the quality of the water to be treated and the BOD removal performance of the anaerobic treatment tank, it becomes impossible to satisfy the BOD / N ratio. Therefore, by bypassing part of the waste water to the anaerobic treatment tank, The N ratio is adjusted.

  Further, the hydrogen sulfide contained in the biogas generated from the anaerobic treatment tank is processed by the desulfurization apparatus 17.

  In the above process, the bypass amount of the anaerobic treatment tank increases depending on the quality of the water to be treated, so that the merit of the anaerobic treatment cannot be fully exhibited, which causes an increase in operating cost.

  As one of the methods for solving the above problems, a wastewater treatment method for removing nitrogen components in the water to be treated using a sulfur denitrification reaction has been proposed. In this method, denitrification efficiency is improved by using hydrogen sulfide generated by anaerobic treatment.

Here, the waste water treatment method will be described with reference to FIG.
In this treatment method, the treatment solution treated in the anaerobic reaction tank 1 flows into the denitrification tank 14 and is circulated between the denitrification tank 14 and the nitrification tank 2 to perform anaerobic treatment. The biogas generated in the reaction tank 1 is sent to the denitrification tank 14 by a blower. In the denitrification tank 14, the denitrification treatment is performed by the reaction of nitrate nitrogen in the circulating water and hydrogen sulfide in the biogas dissolved in the reaction solution by the action of sulfur denitrifying bacteria. The biogas from which hydrogen sulfide has been removed in the denitrification tank 14 is sent to a desulfurization facility for effective use.

JP 2000-189995 A

  However, the above-described method has the following problems.

(1) The nitrogen removal rate of the water to be treated has a relationship of nitrogen removal rate = (R / (1 + R)) when the ratio of circulating water between the denitrification tank 14 and the nitrification tank 2 (circulation ratio: R) is used. In the case of wastewater containing high-concentration nitrogen such as factory wastewater, when the nitrogen removal rate is increased, it is necessary to increase the circulation ratio, so that the power of the circulation pump is increased.

(2) To improve the nitrogen removal rate, it is necessary to increase the circulation ratio. However, since the nitrogen removal rate is not proportional to the circulation ratio, it is difficult to achieve a nitrogen removal rate of 90% or more.

(3) Since denitrification is performed by circulation operation, it is necessary to completely nitrify the nitrogen component flowing into the nitrification tank, and the aeration power of the nitrification tank increases.

(4) Since denitrifying bacteria, which are heterotrophic bacteria having a high growth rate, and sulfur denitrifying bacteria, which are slow-growing autotrophic bacteria, coexist in the denitrification tank, it is not easy to retain sulfur denitrifying bacteria in the denitrification tank. Absent.

Therefore, development of wastewater treatment equipment which can obtain a high nitrogen removal rate can simplify the device configuration is desired.

The wastewater treatment apparatus according to the embodiment comprises an anaerobic treatment tank, an aerobic treatment tank for treating the primary treated water treated in the anaerobic treatment tank, and a secondary treated water treated in the aerobic treatment tank. A sulfur denitrification reactor for treating and discharging as final treated water, and a circulation tank for circulating the primary treated water of the anaerobic treatment tank . The sulfur denitrification reactor is a biogas that passes secondary treatment water only once and discharges nitrate nitrogen or nitrite nitrogen contained in the secondary treatment water from the anaerobic treatment tank by the action of sulfur denitrifying bacteria. The secondary treated water is reduced by hydrogen sulfide contained in the waste water, and the spent biogas is returned to the gas phase part of the anaerobic treatment tank in the sulfur denitrification reactor. Is also returned to the circulation tank .

FIG. 1 is a schematic view showing a wastewater treatment apparatus according to the first embodiment. FIG. 2 is a schematic view showing a wastewater treatment apparatus according to the second embodiment. FIG. 3 is a schematic view showing a wastewater treatment apparatus according to the third embodiment. FIG. 4 is a schematic view showing a wastewater treatment apparatus according to the fourth embodiment. FIG. 5 is a schematic view showing a conventional water treatment apparatus that combines anaerobic treatment and circulation type nitrification / denitrification treatment. FIG. 6 is a schematic view showing a conventional water treatment apparatus combined with sulfur denitrification treatment.

Hereinafter, embodiments will be described in detail with reference to the drawings.
FIG. 1 shows a schematic diagram of a wastewater treatment apparatus 100 according to the first embodiment.
The wastewater treatment apparatus 100 includes an anaerobic treatment tank 1, an aerobic treatment tank 2, a solid- liquid separation tank 3, and a sulfur denitrification reactor 4.

  The anaerobic treatment tank 1 anaerobically treats water to be treated such as sewage and factory wastewater by the action of anaerobic microorganisms. In this anaerobic treatment, biogas containing methane gas as a main component is generated by methane fermentation that decomposes and gasifies organic matter. At this time, if the water to be treated contains a sulfur component, hydrogen sulfide is generated by the action of sulfate-reducing bacteria among the anaerobic microorganisms. Then, the biogas containing hydrogen sulfide is taken out from the vapor phase of the anaerobic treatment tank 1 through the gas line 10 to the subsequent processing unit.

  The aerobic treatment tank 2 has a blower 5 for blowing a large amount of air near its bottom. In the aerobic treatment tank 2, the anaerobic treated water (primary treated water) treated in the anaerobic treatment tank 1 is aerobically treated by the action of aerobic microorganisms, and nitrogen components contained in the anaerobic treated water are nitrated. Oxidizes to nitrogen or nitrite nitrogen.

The solid- liquid separation tank 3 separates aerobic microorganisms from the overflow water (aerobic treated water) (secondary treated water) of the aerobic treatment tank 2, and the sludge containing the separated aerobic microorganisms is favored by the sludge return pump 6. Return to the tempering tank 2. The aerobic treated water (secondary treated water) containing nitrate nitrogen or nitrite nitrogen from which aerobic microorganisms have been separated and removed is introduced into the sulfur denitrification reactor 4 from the bottom of the sulfur denitrification reactor 4. .

  The sulfur denitrification reactor 4 has a carrier 7 holding a high concentration of sulfur denitrifying bacteria in the liquid. The carrier 7 is desirably a material having a surface on which microorganisms are easily rooted. For example, it is possible to suspend a string-like material or to use a material having a specific gravity lighter than water. In addition, it is desirable that the carrier 7 is filled in the upper layer portion of the liquid of the sulfur denitrification reactor 4 without a gap in order to allow biogas and aerobic treated water described later to pass through effectively. On the other hand, it is desirable that there is enough space to allow the flow of the biogas described later.

  Further, the sulfur denitrification reactor 4 has an air diffuser 9 for supplying biogas sent from the anaerobic treatment tank 1 by the blower 8 from below the carrier 7 in the liquid. That is, the biogas containing hydrogen sulfide generated in the anaerobic treatment tank 1 is blown into the sulfur denitrification reactor 4 by the blower 8 from below the support 7 through the air diffuser 9.

  At this time, the nitrate nitrogen produced in the aerobic treatment tank 2 is sulfur-denitrifying bacteria held by the carrier 7 in the sulfur denitrification reactor 4 due to hydrogen sulfide contained in the biogas generated from the anaerobic treatment tank 1. Is reduced and discharged as nitrogen gas outside the system. On the other hand, hydrogen sulfide contained in biogas is oxidized into elemental sulfur or sulfuric acid. Sulfur deposits on the surface of the support 7 and adheres thereto.

  The aerobic treated water introduced into the sulfur denitrification reactor 4 is separated from the aerobic microorganisms in the sludge in the aerobic treatment tank 2 because the aerobic microorganisms are separated by the solid-liquid separation tank 3. Inflow into the denitrification reactor 4 can be suppressed. For this reason, in addition to the sulfur denitrifying bacteria held by the carrier 7 in the sulfur denitrifying reactor 4, it is not necessary for the denitrifying bacteria that are heterotrophic bacteria having a relatively high growth rate to coexist in the sulfur denitrifying reactor 4. Only denitrifying bacteria can be grown. In particular, the aerobic treated water introduced into the sulfur denitrification reactor 4 is a case where denitrifying bacteria, which are heterotrophic bacteria, flow into the sulfur denitrification reactor 4 because organic matter is reduced by the aerobic treatment. However, since its growth is limited, sulfur denitrifying bacteria can be preferentially grown in the sulfur denitrifying reactor 4.

  In the sulfur denitrification reactor 4, the aerobic treated water and the biogas are supplied in the same direction (in parallel flow) from the bottom upward, so that the sulfur denitrifying bacteria held below the carrier 7 is upward. The reaction efficiency is higher than that of That is, since the hydrogen sulfide and nitric acid nitrogen having a higher concentration react below the support 7 than above, the reaction efficiency increases. For this reason, when hydrogen sulfide is oxidized to elemental sulfur, more elemental sulfur is attached to the lower side of the support 7.

  In this way, the simple sulfur adhering to the lower side of the carrier 7 is easily separated from the carrier 7 by causing the carrier 7 to flow with the biogas blown through the air diffuser 9. For this reason, the malfunction which the sulfur denitrification reactor 4 obstruct | occludes with the elemental sulfur adhering to the support | carrier 7 can be prevented.

  As described above, according to the wastewater treatment apparatus 100 of the present embodiment, the aerobic treatment water treated in the aerobic treatment tank 2 is subjected to a transient treatment that passes the sulfur denitrification reactor 4 only once. In addition, it is not necessary to install a circulation pump in the sulfur denitrification reactor 4, the apparatus configuration can be simplified, the power for operating the circulation pump can be reduced, and the manufacturing cost and running cost of the apparatus can be reduced.

  In addition, according to the present embodiment, the sulfur denitrification treated water (final treated water) treated in the sulfur denitrification reactor 4 is water from which nitrate nitrogen in the aerobic treated water has been removed, and is thus discharged directly into a river or the like. It is not necessary to return to the anaerobic treatment tank 1 or the aerobic treatment tank 2. Therefore, the processing steps can be simplified correspondingly, and the configuration of a pump or the like for returning the flow becomes unnecessary. On the other hand, since the water discharged from the reactor 4 is not returned to the anaerobic treatment tank 1 or the aerobic treatment tank 2, the treatment in each of the tanks 1 and 2 is not affected.

  Furthermore, according to this embodiment, by setting the ratio of nitrogen and sulfur flowing into the sulfur denitrification reactor 4 to an appropriate value, the nitrogen removal rate can be increased to 90% or more, theoretically 100% It is possible to obtain a nitrogen removal rate.

FIG. 2 is a schematic view of the waste water treatment apparatus 110 according to the second embodiment.
This waste water treatment device 110 has a biogas circulation line 12 for returning the gas (biogas with reduced hydrogen sulfide) discharged from the sulfur denitrification reactor 4 to the anaerobic treatment tank 1 (and the anaerobic treatment circulation tank 11). Except having, it has the structure substantially the same as the waste water treatment equipment 100 of 1st Embodiment mentioned above. Therefore, here, the same reference numerals are given to components that function in the same manner as in the first embodiment, and detailed description thereof will be omitted.

  In this embodiment, the biogas charged into the sulfur denitrification reactor 4 via the gas line 10, the blower 8, and the air diffuser 9 passes through the carrier 7 and then passes through the biogas circulation line 12. Returned to the anaerobic treatment tank 1. Since the biogas returned by the biogas circulation line 12 is a gas from which hydrogen sulfide has been removed in the sulfur denitrification reactor 4, when this gas is supplied to the upper part of the anaerobic treatment tank 1, the anaerobic treatment tank 1 The hydrogen sulfide concentration in the gas phase part at the upper part of the substrate decreases.

  Thus, when the hydrogen sulfide concentration in the gas phase portion of the anaerobic treatment tank 1 decreases, the hydrogen sulfide dissolved in the liquid phase of the anaerobic treatment tank 1 becomes biogas (gas phase) due to gas-liquid equilibrium. Move to. That is, in this case, hydrogen sulfide is extracted from the liquid phase to the gas phase until the dissolved sulfide dissolved in the liquid phase and the hydrogen sulfide concentration in the gas phase reach an equilibrium state.

  Thus, the hydrogen sulfide recovered from the liquid phase of the anaerobic treatment tank 1 is sent to the air diffuser 9 in the sulfur denitrification reactor 4 through the gas line 10 by the blower 8, and sulfur is passed through the air diffuser 9. It is introduced into the bottom of the denitrification reactor 4. That is, according to the present embodiment, the amount of hydrogen sulfide supplied to the sulfur denitrification reactor 4 can be increased as compared with the first embodiment. Thereby, the denitrification efficiency in the sulfur denitrification reactor 4 can be improved.

  On the other hand, as described above, the hydrogen sulfide concentration in the liquid phase of the anaerobic treatment tank 1 can be reduced by extracting the hydrogen sulfide dissolved in the liquid phase of the anaerobic treatment tank 1. As described above, the hydrogen sulfide concentration in the liquid phase of the anaerobic treatment tank 1 can be reduced simply by feeding the gas in which the hydrogen sulfide is thinned from the sulfur denitrification reactor 4 into the gas phase of the anaerobic treatment tank 1. However, in this embodiment, the gas in which hydrogen sulfide is thinned is also fed into the gas phase of the anaerobic treatment tank 11 connected in parallel with the anaerobic treatment tank 1.

  When the sulfur component contained in the liquid phase (treated water) of the anaerobic treatment tank 1 is very large, the produced hydrogen sulfide has an adverse effect on the anaerobic bacteria present in the anaerobic treatment tank 1, particularly methanogens. Sometimes. In such a case, the liquid phase of the anaerobic treatment tank 1 is circulated by circulating the biogas desulfurized in the sulfur denitrification reactor 4 in the upper part (gas phase) of the anaerobic treatment circulation tank 11 as in this embodiment. The concentration of hydrogen sulfide contained in the water can be reduced, and anaerobic treated water with reduced hydrogen sulfide concentration can be circulated to the anaerobic treatment tank 1. This also makes it possible to prevent anaerobic bacteria from being inhibited by hydrogen sulfide.

  As described above, according to the present embodiment, in addition to being able to achieve the same effects as those of the first embodiment described above, the hydrogen sulfide purified by the anaerobic treatment of the sulfur component contained in the water to be treated is obtained. , Since it can be removed from the treated water in the anaerobic treatment tank 1 and led to the sulfur denitrification reactor 4, inhibition of the anaerobic treatment tank 1 by hydrogen sulfide is prevented, and desulfurization in the sulfur denitrification reactor 4 is prevented. Nitrogen efficiency can be improved.

FIG. 3 is a schematic view of the waste water treatment apparatus 120 according to the third embodiment.
This waste water treatment apparatus 120 removes the anaerobic treatment circulation tank 11 and adds the denitrification tank 14 for circulating and denitrifying the treated water in the aerobic treatment tank 2, and the waste water of the second embodiment described above. It has substantially the same structure as the processing apparatus 110. Therefore, here, the same reference numerals are given to components that function in the same manner as in the second embodiment, and detailed description thereof will be omitted.

  According to this embodiment, the anaerobic treated water treated in the anaerobic treatment tank 1 is guided to the aerobic treatment tank 2 through the denitrification tank 14 provided in the subsequent stage. The aerobic treated water containing nitrate nitrogen generated in the aerobic treatment tank 2 is guided to the sulfur denitrification reactor 4 after the aerobic microorganisms are removed in the solid-liquid separation tank 3.

  A part of the treated water in the aerobic treatment tank 2 is returned to the denitrification tank 14 by the circulation pump 13 and is circulated again to the aerobic treatment tank 2. A total nitrogen meter 15 (nitrogen concentration meter) is installed at the waste liquid outlet of the sulfur denitrification reactor 4 so that the nitrogen concentration of the final treated water discharged from the sulfur denitrification reactor 4 is measured. Yes.

The denitrification reaction by sulfur denitrifying bacteria in the sulfur denitrifying reactor 4 is shown in the following formula (1).
_{^{5HS - + 8NO 3 - + 3H}} + → 5SO 4 2- + 4N 2 + 4H 2 O ··· (1)
As can be seen from the equation (1), denitrification is possible when the ratio of nitrogen component to sulfur component (N / S ratio) flowing into the sulfur denitrification reactor 4 is 0.7 or less. However, when the component of the water to be treated to be treated by this apparatus is less sulfur component than the nitrogen component, the planned nitrogen removal rate cannot be obtained.

  On the other hand, since BOD (biochemical oxygen demand) component remains in the anaerobic treated water, the treated water containing nitric acid generated in the aerobic treatment tank 2 is returned to the denitrification tank 14 by the circulation pump 13 and denitrification tank. Denitrify at 14.

  At this time, the nitrogen concentration contained in the final treated water discharged from the sulfur denitrification reactor 4 is measured by the total nitrogen meter 15, and the circulation flow rate by the circulation pump 13 is adjusted based on the measured value. The ratio of denitrification and denitrification in the denitrification tank 14 is adjusted.

  Actually, when the measured value by the total nitrogen meter 15 becomes larger than the reference value, the flow rate by the circulation pump 13 is increased to increase the denitrification in the denitrification tank 14, and the measured value becomes smaller than the reference value. The flow rate by the circulation pump 13 is decreased.

  By such adjustment, stable final treated water can be obtained even when the sulfur component concentration and the nitrogen component concentration contained in the water to be treated to be treated by this apparatus vary. Further, since the operation of the circulation pump 13 is controlled to control the denitrification amount of the entire apparatus, the circulation flow rate of the treated water by the circulation pump 13 can be reduced as compared with an apparatus having no sulfur denitrification reactor 4. It is possible to reduce the power of the circulation pump.

  As described above, according to the present embodiment, stable final treated water can be obtained even when the sulfur component concentration and nitrogen component concentration in the treated water fluctuate, and the flow rate of the circulation pump can be reduced. Therefore, the power of the circulation pump can be reduced. Moreover, according to this embodiment, since the sulfur denitrification reactor 4 by sulfur denitrifying bacteria and the denitrification tank 14 by nitrifying denitrifying bacteria are provided separately, it is not necessary to coexist different types of denitrifying bacteria in one reaction tank.

FIG. 4 is a schematic view of the waste water treatment apparatus 130 according to the fourth embodiment.
This waste water treatment apparatus 130 is the first implementation described above except that it has a nitric acid meter 16 (nitric acid concentration meter) for measuring the concentration of nitrate nitrogen contained in the final treated water discharged from the sulfur denitrification reactor 4. It has substantially the same structure as the wastewater treatment apparatus 100 of the form. Therefore, here, the same reference numerals are given to components that function in the same manner as in the first embodiment, and detailed description thereof will be omitted.

  The waste water treatment apparatus 130 of this embodiment measures the nitrate nitrogen concentration contained in the final treated water discharged from the sulfur denitrification reactor 4 via the nitric acid meter 16, and based on the measurement result, the aerobic treatment tank The amount of air supplied to the aerobic treatment tank 2 is adjusted by the second blower 5.

  In this waste water treatment apparatus 130, after the BOD component contained in the anaerobic treated water is oxidized by the aerobic microorganism in the aerobic treatment tank 2, the ammonia nitrogen of the treated water is oxidized to nitrate nitrogen by the nitrifying bacteria. . Therefore, the amount of nitrate nitrogen produced in the aerobic treatment tank 2 is proportional to the amount of oxygen charged into the aerobic treatment tank 2 by the blower 5.

  On the other hand, the nitrate nitrogen produced in the aerobic treatment tank 2 is denitrified by the sulfur denitrification reactor 4 in a transient manner. For this reason, the nitrate nitrogen which can be removed by the whole amount of hydrogen sulfide flowing into the sulfur denitrification reactor 4 by the blower 8 is removed. That is, it is desirable that the amount of nitrate nitrogen to be generated in the aerobic treatment tank 2 is an amount that can be removed by the sulfur denitrification reactor 4.

  Therefore, in this embodiment, the nitrate nitrogen concentration contained in the final treated water discharged from the sulfur denitrification reactor 4 is measured by the nitric acid meter 16, and the aerobic treatment is performed by the blower 5 so that the value becomes constant. The amount of air fed into the tank 2 was adjusted. Thereby, the production | generation of excess nitrate nitrogen can be stopped and it becomes possible to reduce the amount of aeration air thrown into the aerobic processing tank 2. FIG. That is, according to this embodiment, the power of the blower 5 of the aerobic treatment tank 2 can be reduced.

  In addition, according to the present embodiment, hydrogen sulfide contained in the biogas is also removed simultaneously with the removal of nitrate nitrogen, so by adjusting the concentration of nitrate nitrogen contained in the final treated water to be constant, It is possible to perform reliable removal.

  According to this embodiment, aeration power required in the aerobic treatment tank 2 can be reduced while removing hydrogen sulfide contained in biogas.

  According to the waste water treatment apparatus of at least one embodiment described above, by having the sulfur denitrification reactor 4 on the downstream side of the anaerobic treatment tank 1 and the aerobic treatment tank 2, the apparatus configuration can be simplified and high nitrogen removal is possible. Rate can be obtained.

Although several embodiments have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.
Hereinafter, the invention described in the scope of claims at the beginning of the application of the present application will be added.
[1]
An anaerobic treatment tank;
An aerobic treatment tank for treating the primary treated water treated in the anaerobic treatment tank;
A sulfur denitrification reactor that treats the secondary treated water treated in this aerobic treatment tank and discharges it as final treated water,
The sulfur denitrification reactor passes the secondary treated water only once and discharges nitrate nitrogen or nitrite nitrogen contained in the secondary treated water from the anaerobic treatment tank by the action of sulfur denitrifying bacteria. To remove nitrogen from the secondary treated water by reducing with hydrogen sulfide contained in the biogas produced,
Wastewater treatment equipment.
[2]
Further comprising an individual liquid separation tank for separating aerobic microorganisms from the secondary treated water and returning them to the aerobic treatment tank, and feeding the secondary treated water separated from the aerobic microorganisms to the sulfur denitrification reactor;
[1] The waste water treatment apparatus.
[3]
The sulfur denitrification reactor has a carrier for holding the sulfur denitrification bacteria in the secondary treated water sent to the sulfur denitrification reactor, and introduces the secondary treated water from the bottom of the sulfur denitrification reactor. Injecting the biogas from below the carrier,
The wastewater treatment apparatus according to [1] or [2].
[4]
The spent biogas used in the sulfur denitrification reactor is returned to the gas phase part of the anaerobic treatment tank.
The wastewater treatment apparatus according to any one of [1] to [3].
[5]
It further has a circulation tank for circulating the primary treated water of the anaerobic treatment tank,
Return the spent biogas to the circulation tank,
[4] The waste water treatment apparatus.
[6]
A nitrogen concentration meter for measuring the nitrogen concentration of the final treated water discharged from the sulfur denitrification reactor,
A denitrification tank for denitrifying by circulating the secondary treated water of the aerobic treatment tank,
Adjusting the amount of secondary treated water to be circulated to the denitrification tank based on the measurement result by the nitrogen concentration meter,
[1] The waste water treatment apparatus.
[7]
A nitric acid concentration meter for measuring the nitric acid concentration of the final treated water discharged from the sulfur denitrification reactor,
Adjusting the amount of air supplied to the aerobic treatment tank based on the measurement result by the nitric acid concentration meter,
[1] The waste water treatment apparatus.
[8]
Treat the treated water in an anaerobic treatment tank,
Treat the primary treated water treated in this anaerobic treatment tank in the aerobic treatment tank,
The secondary treated water treated in this aerobic treatment tank is passed through a sulfur denitrification reactor only once, and nitrate nitrogen or nitrite nitrogen contained in the secondary treated water is anaerobic by the action of sulfur denitrifying bacteria. Reduced with hydrogen sulfide contained in biogas discharged from the treatment tank and discharged as final treated water,
Wastewater treatment method.
[9]
Measure the nitrogen concentration of the final treated water discharged from the sulfur denitrification reactor,
Based on this measurement result, adjust the amount of circulating the secondary treated water of the aerobic treatment tank to the denitrification tank,
[8] The waste water treatment method.
[10]
Measure the concentration of nitric acid in the final treated water discharged from the sulfur denitrification reactor,
Based on this measurement result, adjust the amount of air supplied to the aerobic treatment tank,
[8] The waste water treatment method.

DESCRIPTION OF SYMBOLS 1 ... Anaerobic processing tank, 2 ... Aerobic processing tank, 3 ... Solid- liquid separation tank, 4 ... Sulfur denitrification reactor, 7 ... Carrier, 9 ... Air diffuser, 11 ... Anaerobic processing circulation tank, 12 ... Biogas circulation Line, 13 ... Circulation pump, 14 ... Denitrification tank, 15 ... Total nitrogen meter, 16 ... Nitric acid meter, 100, 110, 120, 130 ... Waste water treatment equipment.

Claims (5)

An anaerobic treatment tank;
An aerobic treatment tank for treating the primary treated water treated in the anaerobic treatment tank;
A sulfur denitrification reactor for treating secondary treated water treated in the aerobic treatment tank and discharging it as final treated water;
A circulation tank for circulating the primary treated water of the anaerobic treatment tank ,
The sulfur denitrification reactor passes the secondary treated water only once and discharges nitrate nitrogen or nitrite nitrogen contained in the secondary treated water from the anaerobic treatment tank by the action of sulfur denitrifying bacteria. is reduced with hydrogen sulfide contained in the biogas have rows nitrogen removal of the secondary treatment water,
Returning the used biogas in the sulfur denitrification reactor to the gas phase part of the anaerobic treatment tank and returning the used biogas to the circulation tank,
Wastewater treatment equipment. Further comprising a solid- liquid separation tank for separating aerobic microorganisms from the secondary treated water and returning them to the aerobic treatment tank, and feeding the secondary treated water from which the aerobic microorganisms have been separated to the sulfur denitrification reactor,
The waste water treatment apparatus of Claim 1. The sulfur denitrification reactor has a carrier for holding the sulfur denitrification bacteria in the secondary treated water sent to the sulfur denitrification reactor, and introduces the secondary treated water from the bottom of the sulfur denitrification reactor. Injecting the biogas from below the carrier,
The waste water treatment apparatus of Claim 1 or Claim 2. A nitrogen concentration meter for measuring the nitrogen concentration of the final treated water discharged from the sulfur denitrification reactor,
A denitrification tank for denitrifying by circulating the secondary treated water of the aerobic treatment tank,
Adjusting the amount of secondary treated water to be circulated to the denitrification tank based on the measurement result by the nitrogen concentration meter,
The waste water treatment apparatus of Claim 1. A nitric acid concentration meter for measuring the nitric acid concentration of the final treated water discharged from the sulfur denitrification reactor,
Adjusting the amount of air supplied to the aerobic treatment tank based on the measurement result by the nitric acid concentration meter,
The waste water treatment apparatus of Claim 1.

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