JP2006122771A - Fluid treatment method and fluid treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid treatment method and a fluid treatment system which enable the removal of nitrogen from a nitrogen compound-containing fluid in a shorter time and at a lower cost than before. <P>SOLUTION: The fluid treatment method comprises a process where desulfurized wastewater containing ammonia nitrogen (NH<SB>3</SB>-N) is supplied to a microorganism holding carrier (2) made of sponge holding nitrifying bacteria, and the ammonia nitrogen (NH<SB>3</SB>-N) contained in the desulfurized wastewater is nitrified by the action of the nitrifying bacteria, and a process where the desulfurized wastewater containing nitrite nitrogen (NO<SB>2</SB>-N) or nitrate nitrogen (NO<SB>3</SB>-N) generated by the nitrification of the ammonia nitrogen (NH<SB>3</SB>-N), and elemental sulfur (S<SP>0</SP>) are supplied to an upflow anaerobic sludge bed (7) holding sulfur oxidizing denitrifying bacteria consuming the elemental sulfur (S<SP>0</SP>), and the nitrite nitrogen (NO<SB>2</SB>-N) or nitrate nitrogen (NO<SB>3</SB>-N) in the desulfurized wastewater is decomposed by the action of the sulfur oxidizing denitrifying bacteria to generate nitrogen gas (N<SB>2</SB>). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and system for processing a fluid for reuse, discharge or the like.

In thermal power plants and other various plants, ammonia water is used to adjust the pH of an ion exchange resin for producing pure water, so ammonia nitrogen (NH ₃ -N) with a high concentration (for example, several thousand ppm) is used. Contains wastewater. Ammonia nitrogen is an ammonium salt represented by nitrogen contained therein, that is, nitrogen in the form of ammonia. In addition, in the desulfurization effluent discharged from the flue gas desulfurization unit of the thermal power plant, ammonia nitrogen as a reducing agent used in the denitration process leaks to the desulfurization unit, so low concentration (for example, 50 ppm or less) of ammonia nitrogen is present. include. These ammonia-nitrogen-containing wastewater is treated in large quantities every day for the purpose of reuse or release.

However, in such wastewater treatment, the concentration and discharge amount of various components contained in the treated wastewater are severely restricted under national wastewater regulations. In particular, for nitrogen compounds such as ammonia nitrogen, nitrogen is subject to wastewater regulation as a causative substance of eutrophication, and nitrite nitrogen (NO ₂ -N) that is oxidized and harmful in an aerobic environment. ) Or nitrate nitrogen (NO ₃ -N), and the consumption of oxygen in an aerobic environment may cause an increase in chemical oxygen demand (COD), which is the subject of wastewater regulations. For reasons, it must be removed before discharge. Nitrite nitrogen (NO ₂ —N) or nitrate nitrogen (NO ₃ —N) is nitrogen in the form of nitrous acid or nitric acid, as is ammonia nitrogen (NH ₃ —N). Nitrite nitrogen includes nitrous acid (HNO ₂ ) as a gas and nitrate ions (NO ₂ ⁻ ) that may exist in an aqueous solution, and nitrate nitrogen also includes nitric acid (HNO ₃ ) and nitrate ions (NO ₃ ^2- ).

  A physicochemical treatment method or a biochemical treatment method is used as a treatment method of the ammonia nitrogen-containing waste water.

As the physicochemical treatment method, the pH of the waste water is raised to about 12 using an alkaline aqueous solution or the like, and then the waste water is aerated with air or oxygen to remove the gasified ammonia nitrogen. The law is known. This treatment method is mainly applied to wastewater containing ammonia nitrogen having a high concentration. However, this processing method includes
(1) It is difficult to treat ammonia nitrogen to a concentration that can be released;
(2) Large cost for aeration equipment and power,
(3) There is a problem that the chemical added to neutralize the wastewater is expensive. Therefore, in light of the fact that effluent regulations are expected to be strengthened in the future, it is necessary to take immediate measures for the treatment of wastewater containing ammonia nitrogen in thermal power plants and other various plants.

In addition, as a biochemical treatment method, an aerobic anaerobic progressive biological method in which wastewater flows through an aerobic treatment tank and an anaerobic treatment tank in order and performs biological treatment is widely used. Thus, so-called denitrification that generates nitrogen gas (N ₂ ) can be performed.

As a conventional aerobic treatment, an activated sludge method is known in which the introduced waste water is aerated to generate activated sludge by aerobic microorganisms (for example, nitrifying bacteria) and precipitate this. In this method, ammonia nitrogen in waste water is oxidized by the action of nitrifying bacteria to produce nitrite nitrogen (NO ₂ -N), and further oxidized to produce nitrate nitrogen (NO ₃ -N). Accordingly, in the waste water, one or both of nitrite nitrogen and nitrate nitrogen are contained as a product of nitrification.

Further, as the latter-stage anaerobic treatment, there is a method in which the product of the first-stage aerobic treatment (nitrification) is reduced to nitrogen gas by the action of anaerobic microorganisms under anaerobic conditions. However, when processing a fluid containing almost no organic matter such as desulfurization effluent, it is necessary to add organic matter (for example, methanol [CH ₃ OH], etc.) as an electron donor in the denitrification reaction in an anaerobic treatment tank. There is.

  The aerobic and anaerobic progressive biological method is applied to low-concentration ammonia nitrogen-containing wastewater, and biologically treated wastewater is appropriately subjected to advanced treatment according to wastewater regulations according to the purpose of reuse or release. Is done.

However, for the aerobic treatment in the previous stage,
(1) The nitrification reaction rate is slow, and nitrification does not occur especially at low temperatures, so a large tank for storing wastewater is required.
(2) When nitrification reaction does not occur, denitrification cannot be carried out by anaerobic treatment at the later stage.
(3) There is a problem that a large cost is required for the equipment for aeration and the power consumption thereof, and there is a problem that a large amount of organic matter is added to the anaerobic treatment in the subsequent stage, so that a very large cost is required. .

  Patent Document 1 below describes a denitrification treatment apparatus and a denitrification treatment method as anaerobic treatment means that can efficiently remove nitrate nitrogen in raw water such as groundwater while stabilizing it.

JP 2004-154700 A

However, in order to perform denitrification from wastewater from thermal power plants and other various plants, these wastewaters do not contain nitrite nitrogen (NO ₂ -N), nitrate nitrogen (NO ₃ -N), etc. In this case, it is necessary to perform a nitrification step of decomposing nitrogen compounds (such as ammonia nitrogen) in raw water into nitrate nitrogen (NO ₃ -N) or the like as a pretreatment. Therefore, even if the denitrification treatment apparatus and the denitrification treatment method of the above-mentioned document are applied, if the treatment speed in the previous nitrification step is slow, denitrification takes a long time as a whole.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a fluid treatment method and a fluid treatment system that can denitrify a fluid containing a nitrogen compound in a shorter time and at a lower cost than conventional ones. To do.

  The fluid treatment method of the present invention comprises supplying a fluid containing a nitrogen compound to an aerobic treatment means that retains aerobic microorganisms, and nitrifying the nitrogen compound in the fluid by the action of the aerobic microorganisms; Supplying the fluid containing the product from the nitrification of the compound and the reduced sulfur component to the anaerobic treatment means holding the anaerobic microorganism consuming the sulfur component, and decomposing the product by the action of the anaerobic microorganism And a step of generating nitrogen, and as the aerobic treatment means, a microorganism holding carrier made of a porous material holding the aerobic microorganisms is used.

In a specific embodiment of the above method, the product is one or both of nitrite nitrogen (NO ₂ —N) and nitrate nitrogen (NO ₃ —N).

  In a more specific aspect, the mass of the organic substance contained in the fluid is 2.85 times or less of the mass of nitrogen constituting the nitrogen compound.

  Moreover, as a sulfur component in a reduced state, a by-product during purification or combustion of the sulfur-containing fuel can be used.

  Alternatively, as the anaerobic treatment means, an upflow anaerobic sludge bed that supplies and raises a fluid to be treated from the bottom can be used.

  Furthermore, nitrogen compound-containing wastewater from power plants and other various plants can be treated. In this case, it is possible to denitrify wastewater that comes out when adjusting the pH of the ion-exchange resin provided in the condensate demineralizer or pure water generator used in the plant, or wastewater that comes out of the electric dust collector.

  The fluid treatment system of the present invention includes an aerobic treatment means for retaining an aerobic microorganism that nitrifies a nitrogen compound in the fluid when a fluid containing the nitrogen compound is supplied, and a product obtained by nitrification of the nitrogen compound. Anaerobic treatment means for holding anaerobic microorganisms that consume the sulfur component and decompose the product to produce nitrogen when the fluid and reduced sulfur component are supplied; and And a means for supplying the sulfur component to the anaerobic treatment means, wherein the aerobic treatment means is a microorganism holding carrier made of a porous material for holding the aerobic microorganisms. To do.

In a specific embodiment of the above system, the product is one or both of nitrite nitrogen (NO ₂ —N) and nitrate nitrogen (NO ₃ —N).

  In a more specific aspect, the mass of the organic substance contained in the fluid is 2.85 times or less of the mass of nitrogen constituting the nitrogen compound.

  Moreover, as a sulfur component in a reduced state, a by-product during purification or combustion of the sulfur-containing fuel can be used.

  Alternatively, the anaerobic treatment means can use an upflow anaerobic sludge bed that feeds and raises the fluid to be treated from the bottom.

  Furthermore, nitrogen compound-containing wastewater from power plants and other various plants can be treated. In this case, it is possible to denitrify and repair the waste water that comes out when adjusting the pH of the ion exchange resin provided in the condensate demineralizer or the pure water generator used in the plant or the waste water that comes out of the electric dust collector.

  According to the present invention, a microorganism can be retained at a high concentration (for example, 20,000 to 40,000 mg / L) by using a microorganism-supporting carrier made of a porous material as an aerobic treatment means. The speed of the nitrification process in the previous stage can be increased, and the denitrification treatment can be performed in a short time as a whole. In the subsequent denitrification step, denitrification is performed by the action of anaerobic microorganisms that consume the reduced sulfur component, and therefore, the denitrification treatment can be performed simply by adding an inexpensive sulfur component.

The product of nitrification in the pre-treatment is one or both of nitrite nitrogen (NO ₂ -N) and nitrate nitrogen (NO ₃ -N), so that in the nitrification step, a fluid containing nitrite nitrogen Nitrate nitrogen may be generated as a fluid to be treated, and in the subsequent denitrification step, a fluid containing either nitrite nitrogen or nitrate nitrogen may be supplied to perform denitrification treatment. it can.

  In general, in order to maintain the denitrification reaction, the mass of the organic substance serving as the electron donor in the denitrification reaction is required to be at least 2.85 times the mass of nitrogen constituting the nitrogen compound. Since the sulfur component becomes an electron donor, even if the amount of organic matter in the fluid to be treated is less than the above amount, if the mass of the reduced sulfur component is about 6.86 times the mass of nitrogen, further organic matter is added. Denitrification can be reliably carried out without addition.

  Furthermore, denitrification can be performed at a lower cost by using a by-product during purification or combustion of sulfur-containing fuel as the sulfur component in the reduced state.

  In any of the above cases, by employing an upflow anaerobic sludge bed as an anaerobic treatment means, a stable anaerobic treatment can be maintained even at low temperatures, and a denitrification treatment can be performed reliably. In this upflow anaerobic sludge bed, a biofilm of anaerobic microorganisms that grow by adhering to a reduced sulfur component by self-immobilization (for example, what is called “granule”) is produced as a fluid to be treated or generated. By stirring or mixing with gas (for example, nitrogen gas, methane gas, etc.), the action of microorganisms is activated and the contact area between the microorganisms and the fluid increases, so that the denitrification process can be accelerated. .

Furthermore, since the nitrogen compound containing waste water from a power plant and other various plants can be denitrified, the cost for waste water treatment in various plants can be reduced. Specifically, ammonia nitrogen-containing wastewater discharged when adjusting the pH of the ion exchange resin provided in the condensate demineralizer or pure water generator with ammonia water, or ammonia nitrogen-containing wastewater discharged from the electric dust collector Can be denitrified. More specifically, in an electrostatic precipitator, ammonium water is supplied into a flue (pipe, etc.) through which the exhaust gas of the combustion device passes, and reacted with sulfides in the exhaust gas to produce ammonium sulfide [(NH ₄ ) ₂ SO ₄ ] crystals are produced and recovered, so that the supplied ammonia water flows out as unreacted ammonia nitrogen-containing wastewater, or even when the inside of the electrostatic precipitator is washed with ammonia water. Drainage comes out. In the fluid processing method or system of the present invention, these ammonia nitrogen-containing wastewater can be denitrified.

  FIG. 1 shows a denitrification system 1 for carrying out the denitrification method of the embodiment.

This denitrification system 1 is a system for denitrification from so-called desulfurization effluent discharged from a desulfurization device of a coal-fired power plant. Specifically, ammonia nitrogen (NH ₃ -N) contained in the desulfurization effluent is pre-staged. This is decomposed through the nitrification step and the denitrification step in the subsequent stage to generate harmless nitrogen gas (N ₂ ).

The denitrification system 1 is a specific means for performing the denitrification process,
It is made of a porous material (for example, a chemical sponge) and includes a plurality of microorganism holding carriers 2 that can hold nitrifying bacteria at a high concentration (for example, 20,000 to 40,000 mg / L). An aerobic treatment tank 3 for nitrifying ammonia nitrogen in wastewater by the action of nitrifying bacteria when supplied to the carrier 2;
A sulfur component storage tank 4 and a pump 5 as means for supplying a reduced sulfur component to the wastewater treated in the aerobic treatment tank 3,
Anaerobic which consumes the reduced sulfur component and acts to reduce the product of nitrification contained in the wastewater and generate nitrogen gas 6 when the wastewater treated in the aerobic treatment tank 3 is supplied. An anaerobic treatment tank 7 that retains anaerobic microorganisms (eg, sulfur-oxidizing denitrifying bacteria);
A pump 9 is provided as means for supplying the wastewater treated in the aerobic treatment tank 3 to the anaerobic treatment tank 7.

The product of the nitrification contains one or both of nitrite nitrogen (NO ₂ -N) and nitrate nitrogen (NO ₃ -N), and the nitrite nitrogen is nitrous acid (HNO ₂ ) as a gas. Nitrite ions (NO ₂ ⁻ ) that can exist in the liquid are included, and nitrate nitrogen also includes nitric acid (HNO ₃ ) as a gas and nitrate ions (NO ₃ ²⁻ ) that can exist in the liquid.

The aerobic treatment tank 3 for performing the nitrification process in the previous stage is provided with a pipe line provided with a plurality of nozzles 8 for spraying or dripping the waste water onto the microorganism holding carrier 2, and the waste water supplied from the nozzle 8 is retained by the microorganism. It flows down on the surface or inside of the carrier 2. As a result, the ammonia nitrogen in the waste water is oxidized by the nitrifying bacteria held in the microorganism holding carrier 2, and nitrite nitrogen (NO ₂ -N) and nitrate nitrogen (NO ₃ -N) are produced as products by nitrification. ) Or both.

  In addition, the aerobic treatment tank 3 is configured so that the microorganism holding carrier 2 made of sponge and the like and the nitrifying bacteria form a biofilm, thereby allowing microorganisms to be present at a concentration about 20 times higher than that of a conventional so-called complete mixing reactor. The nitrification process can be speeded up. Furthermore, since the microorganism-retaining carrier 2 made of sponge or the like has a high oxygen dissolving ability, aeration (in a fluid) can be achieved by providing ventilation holes 10 in the upper and lower parts of the aerobic treatment tank 3 to allow ventilation. A good aerobic environment can be maintained without performing aeration. Further, in the aerobic treatment tank 3, a ventilation device (for example, a ventilation fan) may be provided for the ventilation hole 10 provided in the lower part for intake and the ventilation hole 10 provided for the upper part for exhaustion, respectively. Good.

As a reduced sulfur component (specifically, a sulfur component other than sulfate ion [SO ₄ ²⁻ ]) supplied to the aerobic treated wastewater, a solid which is a by-product during purification or combustion of the sulfur-containing fuel Alternatively, a liquid sulfur component can be used. Specifically, hydrogen sulfide ion (HS ⁻ ), thiosulfate ion (S ₂ O ₃ ²⁻ ), elemental sulfur (S ⁰ ), or sulfite ion (SO ₃ ⁻ ) Various sulfur components in a reduced state such as can be used. These sulfur components are stored in the sulfur component storage tank 4 in a state of being mixed with water, for example, and appropriately supplied to the aerobic treated waste water by the pump 5. Further, the sulfur component in the reduced state can be directly supplied to the anaerobic treatment tank 7 in the subsequent stage as well as supplied to the waste water sent to the subsequent denitrification process as in the embodiment.

  The anaerobic treatment tank 7 that performs the subsequent denitrification process holds a biofilm (for example, a granule having a diameter of 1 to 3 mm) 12 formed by the self-immobilization action of the sulfur denitrifying bacteria, and is placed at the bottom of the tank. It is an upflow anaerobic sludge bed in which wastewater to be treated and sulfur components in a reduced state are supplied from a plurality of nozzles 13 to perform water flow treatment. In an upflow anaerobic sludge bed, anaerobic microorganisms can form granules by self-immobilizing action, so that the microorganisms can be maintained at a high concentration (for example, 50,000 mg / L), and the denitrification process can be performed at high speed. Can be achieved. In addition, since the wastewater supplied from the bottom of the tank is treated with high-concentration anaerobic microorganisms in the tank, the frequency of sludge discharge work can be reduced and the denitrification reaction is also promoted. A hood 14 that collects the nitrogen gas 6 generated in the denitrification process and discharges it into the atmosphere is provided in the upper portion of the anaerobic treatment tank 7.

A denitrification reaction using a sulfur component in a reduced state (for example, elemental sulfur [S ⁰ ]) as an electron donor is represented by the following formula.

As this reaction formula shows, sulfate ions (SO ₄ ²⁻ ) are generated in the denitrification step. For example, the sulfate ion can be made harmless gypsum by sending it to an absorption tower that takes out sulfur oxides contained in the desulfurization effluent as gypsum, and can be effectively used for materials such as cement and gypsum board.

  Furthermore, the anaerobic treated waste water is appropriately subjected to advanced treatment such as pH adjustment in accordance with waste water regulations according to the purpose of reuse or discharge.

  FIG. 2 is a flowchart of the denitrification method of the embodiment.

In the denitrification system 1, desulfurization effluent containing ammonia is sent to the aerobic treatment tank 3, and a nitrification process is performed in which ammonia in the effluent is decomposed and oxidized to generate nitrate ions (step [hereinafter referred to as ST]). 1). Specifically, the waste water flows down on the surface or inside of the microorganism holding carrier 2 by spraying the waste water toward the microorganism holding carrier 2 from the nozzle 8 provided in the upper part of the aerobic treatment tank 3. The waste water flowing down the microorganism holding carrier 2 is decomposed and oxidized by the action of nitrifying bacteria held in the microorganism holding carrier 2 to produce nitrite nitrogen (NO ₂ -N), and further oxidized to nitrate nitrogen ( NO ₃ -N) produce. Then, the wastewater further flows down the microorganism holding carrier 2, reaches the bottom of the aerobic treatment tank 3, and is supplied to the anaerobic treatment tank 7 side in the subsequent stage.

  Next, a reduced sulfur component is supplied to the aerobic treated waste water (ST2). Thus, even if the amount of organic matter contained in the wastewater to be treated is not sufficient as an electron donor in the denitrification reaction, a predetermined amount of sulfur component (specifically, about 6.85 times the mass of nitrogen or more) If the sulfur component is present, denitrification can be performed reliably.

  The relationship between the sulfur component and the mass of nitrogen is expressed by the following equation.

From this formula (2), in order for all the nitrate ions (NO ₃ ²⁻ ) in the fluid to be treated to react and become nitrogen gas (N ₂ ), the molar mass of nitrogen (N ₂ ) is 24 g / mol. Since the molar mass of sulfur (S) is 32 g / mol, the ratio between the two is “(6 × 32) / (2 × 14) ≈6.85”, which is about 6. It can be seen that a sulfur component of 85 times or more is necessary.

  Finally, the waste water from the aerobic treatment tank 3 and the reduced sulfur component added thereto are supplied to the anaerobic treatment tank 7 to perform a denitrification step (ST3).

  Here, the amount of organic matter contained in the wastewater to be treated in the denitrification method of the example will be described. In this denitrification method and denitrification system, even when the fluid to be treated does not contain organic substances or has a very low content, desulfurization is achieved by supplying the reduced sulfur component as an electron donor in the denitrification reaction. Nitrogen treatment can be maintained. The amount of organic matter in the treatment target fluid necessary to maintain the denitrification step can be determined based on the following equation representing the denitrification reaction using the organic matter as an electron donor.

Specifically, in order for the denitrification reaction to be established, in general, ² g of the organic substance (C) that is a target component of COD is 2 parts per 1 g · N of nitrate nitrogen contained in nitrate ions (NO ₃ ²⁻ ). It is known that .85 g · COD is necessary. That is, according to this denitrification method, in the conventional method, the fluid that was not denitrified unless an organic substance was added as an electron donor, that is, the mass of the organic substance contained was about 2.85 times or less the mass of the nitrogen component. Even a fluid can be denitrified by adding an inexpensive reduced sulfur component without adding an organic substance. The amount of organic matter or nitrogen in the fluid to be treated can be measured using a measuring device such as a liquid chromatograph.

Further, as shown in the above formula (1), nitrate ions (NO ₃ ²⁻ ) in the waste water are reduced by the action of sulfur oxidative denitrifying bacteria to produce harmless nitrogen gas 6, and in the hood 14 of the anaerobic treatment tank 7. It is collected and discharged into the atmosphere. The wastewater after anaerobic treatment is appropriately subjected to advanced treatment such as pH adjustment in accordance with wastewater regulations according to the purpose of discharge and reuse, and also to the absorption tower to take out the contained sulfate ions as gypsum. Supplied.

  Furthermore, although the flow chart of FIG. 2 shows a series of flow of denitrification treatment, in practice, the fluid to be treated is continuously supplied, and the nitrification step and the denitrification step are continuously carried out accordingly. Can be done.

  As mentioned above, although the denitrification method and the denitrification system of an Example were demonstrated, the nitrogen compound containing waste_water | drain to process is not restricted to the desulfurization waste_water | drain which comes out from the desulfurization apparatus with which the coal-fired power station was equipped, The nitrogen compound which comes out from various plants Contained wastewater can be treated. Examples of the nitrogen compound-containing wastewater other than the desulfurization wastewater discharged from the plant include wastewater discharged at the time of pH adjustment of the ion exchange resin provided in the condensate demineralizer or pure water generator used in the various plants, or electricity Drainage from the dust collector can be denitrified.

  In addition, the denitrification system of the present invention can be incorporated into a part of the wastewater treatment process in a coal-fired power plant, and in accordance with the flow rate of wastewater to be treated, the concentration of nitrogen compounds contained, etc. 3 and the processing speed of the anaerobic processing tank 7 should be adjusted.

  Furthermore, the microorganism holding carrier 2 can be made of a sponge-like material such as a nonwoven fabric or polyurethane, or can be made of a water-retaining material such as ceramics.

  Moreover, although the upward flow anaerobic sludge bed was employ | adopted as the anaerobic processing tank 7 in the Example, it is also possible to employ | adopt the general anaerobic reaction tank which does not use an upward flow.

The figure which shows the denitrification system of an Example. The flowchart of the denitrification method of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Denitrification system, 2 ... Microbe holding carrier, 3 ... Aerobic processing tank, 4 ... Sulfur component storage tank, 5,9 ... Pump, 6 ... Nitrogen gas, 7 ... Anaerobic processing tank, 8, 13 ... Nozzle, 10 ... vent, 12 ... biofilm, 14 ... hood.

Claims (14)

Supplying a fluid containing a nitrogen compound to an aerobic treatment means holding aerobic microorganisms, and nitrifying the nitrogen compound in the fluid by the action of the aerobic microorganisms;
Supplying a fluid containing a product obtained by nitrification of the nitrogen compound and a sulfur component in a reduced state to an anaerobic treatment means holding an anaerobic microorganism that consumes the sulfur component, and the product is produced by the action of the anaerobic microorganism. A process of decomposing and generating nitrogen,
A fluid processing method comprising using a microorganism holding carrier made of a porous material holding the aerobic microorganism as the aerobic processing means. The fluid treatment method according to claim 1, wherein the product is one or both of nitrite nitrogen (NO ₂ —N) and nitrate nitrogen (NO ₃ —N).   3. The fluid processing method according to claim 1, wherein the mass of the organic substance contained in the fluid is 2.85 times or less of the mass of nitrogen constituting the nitrogen compound.   4. The fluid processing method according to claim 1, wherein the sulfur component in the reduced state is generated during purification or combustion of the sulfur-containing fuel.   5. The fluid treatment method according to claim 1, wherein the anaerobic treatment means is an upflow anaerobic sludge bed that feeds and raises a fluid to be treated from the bottom. .   6. The fluid treatment method according to claim 1, wherein the fluid supplied to the aerobic treatment means is nitrogen compound-containing wastewater from a power plant or other various plants.   The fluid treatment method according to claim 6, wherein the nitrogen compound-containing wastewater is drainage discharged at the time of pH adjustment of an ion exchange resin provided in a condensate demineralizer or a pure water generator used in the plant, or an electric dust collector A fluid treatment method characterized by being drained from a wastewater. An aerobic treatment means for holding aerobic microorganisms that nitrify the nitrogen compound in the fluid when a fluid containing the nitrogen compound is supplied;
When a fluid containing a product obtained by nitrification of the nitrogen compound and a sulfur component in a reduced state are supplied, the sulfur component is consumed, and anaerobic microorganisms that act to decompose the product to generate nitrogen are retained. Anaerobic treatment means,
A fluid containing the product and a means for supplying the sulfur component to the anaerobic treatment means,
The fluid processing system, wherein the aerobic processing means is a microorganism holding carrier made of a porous material that holds the aerobic microorganisms. The fluid processing method according to claim 8, wherein the product is a fluid processing method is characterized in that one or both of nitrite nitrogen (NO 2 _-N) and nitrate nitrogen (NO 3 _-N).   10. The fluid treatment system according to claim 8, wherein a mass of an organic substance contained in the fluid is 2.85 times or less of a mass of nitrogen constituting the nitrogen compound.   The fluid processing system according to claim 8, wherein the sulfur component in the reduced state is generated during purification or combustion of the sulfur-containing fuel.   12. The fluid treatment system according to claim 8, wherein the anaerobic treatment means is an upflow anaerobic sludge bed that feeds and raises a fluid to be treated from the bottom. .   13. The fluid treatment system according to claim 8, wherein the fluid supplied to the aerobic treatment means is nitrogen compound-containing waste water from a power plant or other various plants. 14. The fluid treatment system according to claim 13, wherein the nitrogen compound-containing wastewater is drainage discharged at the time of pH adjustment of an ion exchange resin provided in a condensate demineralizer or a pure water generator used in the plant, or an electric dust collector. A fluid treatment system characterized by being drained from water.

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