JP5773381B2 - Ammonia removing apparatus, organic waste processing apparatus and processing method using the same - Google Patents

Description

The present invention provides an ammonia removal device for removing ammonia from livestock manure, food waste, organic wastewater containing high concentration ammoniacal nitrogen, and a methane fermentation treatment of the treatment liquid discharged from the ammonia removal device. The present invention relates to a processing apparatus and a processing method.
In addition, although it is called organic waste including waste and wastewater such as livestock excreta containing the organic matter in high concentration, it may be described in terms of each.

  Conventionally, organic waste containing high concentrations of ammonia nitrogen has been denitrified by various methods to prevent eutrophication of rivers and sea areas. However, the measures for pig manure, chicken manure, cattle manure, horse manure, sheep manure and other livestock manure are currently delayed, and the contamination of groundwater and rivers has become serious. It has become.

  Conventionally, as a method of treating livestock manure, livestock manure (hereinafter, organic waste water) is separated into solid and liquid, and the separated liquid is fermented with methane. At this time, digestion gas containing high concentration of methane is recovered, and after fermentation A method is known in which the liquid (digested liquid) is treated with activated sludge microorganisms. In these treatment methods, a method of reducing the concentration of ammonia nitrogen is performed in order to avoid inhibition of ammonia nitrogen by microorganisms. Specifically, in the stage before methane fermentation, ammonia nitrogen, which is an inhibitory factor in methane fermentation, is stripped with water vapor (see the steam stripping method, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2009-66572)), Remove by volatilization by aeration using air.

Among them, in the steam stripping method, in the stripping tower for stripping, the organic waste water containing ammonia nitrogen at a high concentration flows down from the upper part of the tower, while supplying water vapor from the lower part of the tower, In the stripping tower, the water vapor comes into contact with the organic waste water, and the ammonia component in the organic waste water moves to the water vapor side and is removed from the organic waste water. The water vapor containing ammonia after stripping is generally cooled by a cooler after being discharged from the top of the tower, and recovered as condensed water (recovered liquid) containing ammonia.
Even in the case of the aeration method using air, the ammonia content in the organic waste water can be easily reduced by increasing the liquid temperature, and the condensed water containing ammonia can also be recovered.

  However, in any organic wastewater treatment method, the main components of the recovered liquid are ammonium hydroxide, ammonium bicarbonate, and ammonium carbonate. Among these, ammonium hydroxide dissipates the partial pressure equilibrium ammonia even at room temperature. Therefore, it was necessary to provide an odor countermeasure device after cooling the steam.

JP 2009-66572 A

  The present invention has been made in the background of the above-mentioned problems. By blowing carbon dioxide into a stripping tower, the ammonia stripped from the organic waste liquid reacts with carbon dioxide, and the ammonia content is reduced. It can be recovered as a recovery liquid mainly composed of ammonium bicarbonate and ammonium carbonate which are difficult to diffuse instead of ammonium hydroxide which is easy to diffuse at normal temperature, and after cooling of the gas containing water vapor from the stripping tower It is an object of the present invention to provide an ammonia removing device that can eliminate the need for a deodorizing device for ammonia, an organic waste processing device and a processing method using the ammonia removing device.

  The gist of the present invention for achieving the above object is that the present invention according to claim 1 separates ammonia nitrogen from the organic waste by bringing carbon dioxide gas into contact with the organic waste containing ammonia nitrogen. And a stripping tower for obtaining a treatment liquid.

  The present invention according to claim 2 further includes a heat exchanger for exchanging heat between the organic waste supplied to the stripping tower and the treatment liquid discharged from the bottom of the stripping tower. The ammonia removing apparatus according to claim 1.

Further, the present invention according to claim 3 has a stripping tower for contacting a carbon dioxide gas with an organic waste containing ammonia nitrogen and separating the ammonia nitrogen from the organic waste to obtain a treatment liquid. An ammonia removal device,
An organic waste comprising: a methane fermentation tank for supplying the treatment liquid, subjecting the organic waste from which ammonia nitrogen has been separated to methane fermentation, and performing decomposition of organic matter and recovery of digestion gas It is a processing device for things.

  The present invention according to claim 4 further includes a heat exchanger for exchanging heat between the organic waste supplied to the stripping tower and the treatment liquid discharged from the bottom of the stripping tower. The organic waste processing apparatus according to claim 3.

Furthermore, the present invention according to claim 5 provides:
A combustion apparatus for burning digestion gas generated from the methane fermentation tank;
5. The organic waste treatment apparatus according to claim 3, further comprising an exhaust gas supply unit configured to supply exhaust gas containing carbon dioxide discharged from the combustion apparatus to the stripping tower.

Furthermore, in the present invention according to claim 6, the exhaust gas supply means includes
An exhaust gas supply pipe communicating the combustion device and the stripping tower;
A CO ₂ concentration meter provided in the middle of the exhaust gas supply pipe for measuring the carbon dioxide concentration of the exhaust gas; a flow rate indicating controller provided in the middle of the exhaust gas supply pipe for indicating and adjusting the flow rate of the exhaust gas;
The organic waste processing apparatus according to claim 5, comprising:

  The present invention described in claim 7 is the organic waste processing apparatus according to claim 5 or 6, wherein the combustion apparatus is a digestion gas boiler or a digestion gas generator.

  The present invention according to claim 8 is a stripping method in which carbon dioxide gas is brought into contact with organic waste containing ammonia nitrogen in a stripping tower, and ammonia nitrogen is separated from the organic waste to obtain a treatment liquid. And a methane fermentation step of supplying the treatment liquid, subjecting the organic waste from which the ammoniacal nitrogen has been separated to methane fermentation, and removing organic matter and recovering digestive gas. This is a method for treating organic waste.

  The present invention according to claim 9 heat-exchanges the organic waste supplied to the stripping tower and the treatment liquid discharged from the bottom of the stripping tower. This is a treatment method for radioactive waste.

  According to a tenth aspect of the present invention, the organic gas according to the eighth or ninth aspect is provided, wherein the digested gas is burned after being desulfurized, and the exhaust gas containing the carbon dioxide gas generated at that time is supplied to the stripping tower. This is a treatment method for radioactive waste.

  In the present invention described in claim 11, the temperature of the organic waste during stripping in the stripping tower is 70 ° C or higher and lower than 100 ° C, and any one of claims 8-10. It is the processing method of the organic waste as described in above.

  The present invention described in claim 12 is the organic waste processing method according to any one of claims 8 to 11, wherein the organic waste is derived from livestock manure. .

Here, the ammonia removal device is a gas-liquid that blows carbon dioxide gas from the bottom of the tower and brings ammonia nitrogen in the organic waste into the gas by bringing it into gas-liquid contact with the heated organic waste to be treated. A device that recovers a liquid containing ammonium bicarbonate or ammonium carbonate as a main component by cooling the gas containing these components with a cooler after being discharged from the top of the tower accompanying the gas containing water vapor generated by contact. is there.
The operating condition of the ammonia removing device is usually normal pressure, preferably 85 ° C. to 90 ° C., and is usually stripped with carbon dioxide gas containing water vapor.
As carbon dioxide, in addition to exhaust gas that burns digestion gas collected from the methane fermentation tank, carbon dioxide gas emitted from digestion gas methane gas refining equipment, as well as combustion exhaust gas from general heavy oil, gas cooking boilers, etc. be able to.

  As the methane fermentation tank, a methane fermentation tank, a combined apparatus of an acid fermentation tank and a methane fermentation tank, an upward flow anaerobic treatment apparatus (UASB apparatus), or the like can be adopted. The recovered digestion gas can be used as fuel. In addition, although the processing temperature of methane fermentation in a methane fermentation tank is not limited, For example, it is about 35-38 degreeC in a medium temperature fermentation processing method, and is about 54-56 degreeC in a high temperature fermentation processing method. The residence time is preferably 2 days to 2 weeks.

In the present invention according to claim 1, in the stripping tower for stripping, the organic waste flowing down from the top of the tower is brought into gas-liquid contact by blowing carbon dioxide from the bottom of the tower, so that the organic waste The ammonia component therein moves to the gas side and is removed.
The steam-containing gas containing the ammonia component after stripping is discharged from the top of the stripping tower, then cooled by a cooler, and the main components are ammonium bicarbonate and ammonium carbonate, which hardly dissipate ammonia at room temperature. The recovered liquid can be recovered. Thereby, the deodorizing device for ammonia can be made unnecessary after cooling the water vapor from the stripping tower.

  In this invention of Claim 2, Claim 4, and Claim 9, using the heat exchanger, the organic waste supplied to the stripping tower and the processing liquid discharged from the bottom of the stripping tower Therefore, the amount of water vapor can be reduced by about 15% compared to the conventional steam direct blowing method.

In the present invention according to claim 3 and claim 8, in the stripping tower for stripping, the organic waste is brought into gas-liquid contact with the organic waste to be treated by blowing carbon dioxide gas from the bottom of the tower. Ammonia bicarbonate in the waste was transferred to the gas by moving it into the gas and accompanying the gas containing water vapor generated by gas-liquid contact. It can be recovered as a recovery liquid mainly composed of ammonium carbonate.
In this way, the gas containing the ammonia component after stripping is discharged from the top of the stripping tower and then cooled by a cooler to remove ammonium bicarbonate and ammonium carbonate, which are difficult to dissipate at room temperature. It can be recovered as a recovery liquid containing the main component. Thereby, the deodorizing device for ammonia can be made unnecessary after cooling the gas from the stripping tower.
Moreover, in the ammonia removal apparatus, the treatment liquid (deammonification liquid) obtained by reducing ammonia nitrogen, which is an inhibitory factor in methane fermentation, to a concentration that does not affect methane fermentation is supplied to the methane fermentation tank. In the methane fermenter, digestion gas containing methane that is used as a fuel by methane fermentation by the action of the methane-producing bacteria is recovered, and efficient fermentation treatment is possible.

  In the present invention described in claim 5, the digestion gas generated from the methane fermentation tank is combusted by the combustion device, and at that time, the exhaust gas containing carbon dioxide discharged from the combustion device is supplied to the stripping tower by the exhaust gas supply means. To do. Thereby, the carbon dioxide gas supplied to the stripping tower of the ammonia removing device can be obtained by effectively utilizing the digestion gas generated from the methane fermentation tank.

In this invention of Claim 6, the waste gas containing the carbon dioxide discharged | emitted from the combustion apparatus is supplied to a stripping tower through an exhaust gas supply pipe. In the middle, the flow rate of the exhaust gas is indicated and adjusted with a flow rate indicating controller, and the carbon dioxide concentration of the exhaust gas is measured with a CO ₂ concentration meter. Thereby, the required amount of carbon dioxide that reacts with ammonia can be supplied to perform efficient stripping.

  In the present invention according to claim 10, since the digestion gas before being supplied to the combustion apparatus is desulfurized, generation of hydrogen sulfide and the like can be reduced to prevent air pollution.

  In the present invention described in claim 11, since the temperature of the organic waste during stripping in the stripping tower is set to 70 ° C. or more and less than 100 ° C., ammonia nitrogen is used in the exhaust gas containing a relatively small amount of carbon dioxide gas. Can be transferred into the gas. When the temperature of the organic waste during stripping is less than 70 ° C., the removal rate of ammonia from the organic waste decreases. On the other hand, when the temperature is 100 ° C. or higher, the stripping tower has a specification satisfying the pressure vessel structure standard, resulting in an inconvenience that the equipment cost increases. The preferred temperature of the organic waste during stripping in the stripping tower is 85-90 ° C.

In one Embodiment of this invention, it is a systematic diagram of the processing apparatus of organic waste (livestock manure). In one Embodiment of this invention, it is a graph which shows the relationship between the liquid temperature of the organic waste in a stripping tower, and the removal rate of ammonia.

The present invention will be specifically described below.
FIG. 1 is a system diagram of an organic waste processing apparatus according to an embodiment of the present invention.

  FIG. 1 shows a processing apparatus for livestock manure as organic waste, and the main apparatus configuration is a stock tank 1 for organic waste, an ammonia removal apparatus 2 for separating ammonia nitrogen, and methane fermentation. Digestion gas boiler 4 and digestion gas generator 5 for burning digestion gas obtained by methane fermentation in methane fermentation tank 3, methane fermentation tank 3, and dioxide dioxide discharged from digestion gas boiler 4 and digestion gas generator 5 Exhaust gas supply means 6 for supplying exhaust gas containing carbon to the ammonia removing device 2 is provided.

Hereinafter, these configurations will be described in detail.
The stock solution tank 1 stores liquid organic waste (hereinafter referred to as “stock solution”) obtained by removing contaminants from livestock manure with a screen in order to adjust the supply amount of the stock solution when supplying it to the subsequent processing step. It is a tank, and pH adjustment is performed if necessary.
The stock solution is configured to be supplied to the downstream ammonia removing device 2 through the heat exchanger 11.

  The ammonia removing device 2 has a tray type stripping tower (stripping tower) 2A for discharging and removing a part of the ammoniacal nitrogen in the stock solution. The stripping tower is not limited to a plate type, and may be a packed tower. The heated stock solution is supplied to the upper stage of the tower, the exhaust gas containing carbon dioxide supplied from the exhaust gas supply means 6 is blown to the lower stage of the tower, and the ammonia content in the organic waste is accompanied by the rising steam and the exhaust gas. It rises, is fractionally concentrated by a tray, and is discharged as a vapor containing ammonia from the top of the column. A cooler 7 that cools the steam is connected to the top of the stripping tower 2A by a cooler 7 that uses cooling water as a refrigerant. A recovery liquid tank 8 that recovers the ammonia component as a recovery liquid mainly composed of ammonium bicarbonate and ammonium carbonate is communicated with the downstream portion of the cooler 7.

A recovery liquid storage tank 9 for storing the recovery liquid discharged from the recovery liquid tank 8 is communicated with the downstream portion of the recovery liquid tank 8. A part of the recovered liquid discharged from the recovered liquid tank 8 is refluxed to the upper stage of the stripping tower 2A. Therefore, the recovered liquid tank 8 stores a high concentration ammonium bicarbonate and a condensate containing ammonium carbonate. Further, from the upper part of the recovered liquid tank 8, carbon dioxide gas with reduced ammonia content is released to the atmosphere. In the middle of the process, odorous components such as ammonia contained in a small amount in carbon dioxide gas are deodorized by the deodorizing apparatus 10 including activated carbon. Of the gas released to the atmosphere, unreacted carbon dioxide is recirculated in the exhaust gas supply pipe 16.
Further, a deammonized liquid (hereinafter referred to as “deammonized liquid”) as a processing liquid is extracted from the bottom of the stripping tower 2A, and the raw liquid and heat supplied to the ammonia removing device 2 by the heat exchanger 11 are extracted. It replaces and it adjusts to temperature suitably, and once it stores in the relay tank 12, it becomes the structure supplied to the methane fermentation tank 3 of a back | latter stage.

  The methane fermentation tank 3 is an apparatus for recovering digestion gas containing methane used as fuel by subjecting the deammonification liquid supplied from the ammonia removal apparatus 2 to methane fermentation by the action of methane-producing bacteria. Specifically, the methane fermentation apparatus 3 includes a fermenter that contains a deammonification liquid that is a methane treatment liquid, a draft tube that is disposed vertically in the center of the fermenter, and a draft tube that communicates with the upper part. The methane fermentation tank 3 mainly has a sealed structure covered with a head tank. The digested liquid after fermentation in the methane fermenter 3 is supplied to the digested liquid tank 13 and then treated with activated sludge microorganisms.

  A desulfurization tower 14 is communicated with the subsequent stage of the methane fermentation tank 3 to desulfurize digestion gas discharged from the methane fermentation tank 3. A gas holder 15 communicates with the downstream portion of the desulfurization tower 14 where the desulfurized digestion gas is temporarily stored. A digestion gas boiler (combustion device) 4 and a digestion gas generator (combustion device) 5 using digestion gas as fuel are disposed downstream of the gas holder 15. Digestion gas is burned in these combustion devices. In the digestion gas boiler 4, the digestion gas after desulfurization is burned to generate water vapor. This steam is used as the steam supplied to the stripping tower 2A. Note that the steam is supplied directly to the lower part of the storage tower 2A, the case where it is supplied to the stock solution after heat exchange, and a part of the deammonia liquid discharged from the stripping tower 2A is again stripped. When it is refluxed to the middle stage of 2A, it may be mixed into the refluxed deammonification liquid.

Exhaust gas containing carbon dioxide generated during combustion communicates with the digestion gas boiler 4 and the digestion gas generator 5 via the exhaust gas supply pipe 16 and the lower column and the bottom of the stripping tower 2A. Further, a flow rate indicating controller 17 for indicating and adjusting the flow rate of the exhaust gas is provided in the upstream portion of the exhaust gas supply pipe 16, while a CO ₂ concentration for measuring the carbon dioxide concentration of the exhaust gas is provided in the downstream portion of the exhaust gas supply pipe 16. A total of 18 is provided. When the exhaust gas is excessively generated, a part (excess) of the exhaust gas is released into the atmosphere from the upstream portion of the flow rate indicating controller 17 of the exhaust gas supply pipe 16.

  In FIG. 1, P1 is a first pump for pumping the stock solution in the stock solution tank 1 to the stripping tower 2A through the heat exchanger 11, and P2 is for heat exchange of the deammonification liquid discharged from the bottom of the stripping tower 2A. This is a second pump that pumps to the relay tank 12 via the vessel 11. P3 is a third pump that pumps the deammonia solution stored in the relay tank 12 to the methane fermentation tank 3, and P4 is a fourth pump that pumps the exhaust gas from the combustion devices 4 and 5 to the stripping tower 2A.

Next, a processing method for processing livestock manure will be described based on the system diagram of the livestock manure processing apparatus according to the present invention described in FIG.
First, livestock manure is supplied to the screen to remove impurities from the livestock manure (not shown). The stock solution separated by the screen is pumped to the upper stage of the stripping tower 2A of the ammonia removing device 2 by the first pump P1. On the way, the stock solution passes through the heat exchanger 11 and is heated to 85 to 90 ° C. by exchanging heat with the deammonification liquid discharged from the bottom of the stripping tower 2A. The undiluted solution supplied to the upper stage of the tower flows down in the tower, while the lower stage of the tower is injected with exhaust gas containing carbon dioxide supplied from steam for heating and the exhaust gas supply means 6, and the ammonia content in the organic waste is reduced. Along with the gas, it is discharged from the top of the tower.

In the exhaust gas containing carbon dioxide, ammonia stripped from the liquid reacts with carbon dioxide in the exhaust gas to produce ammonium bicarbonate and ammonium carbonate from the ammonia content. Hereinafter, this reaction is shown in the following formula.
NH ₃ + CO ₂ + H ₂ O → NH ₄ HCO ₃
Or 2NH ₃ + CO ₂ + H ₂ O → (NH ₄ ) ₂ CO ₃

It is cooled by a cooler 7 using cooling water as a refrigerant, and an ammonia component is stored in a recovery liquid tank 8 as a recovery liquid mainly composed of ammonium bicarbonate and ammonium carbonate.
Next, the recovered liquid in the recovered liquid tank 8 is stored in the recovered liquid storage tank 9. At this time, a part of the recovered liquid discharged from the recovered liquid tank 8 is refluxed (restripped) to the upper stage of the stripping tower 2A. Thereby, the density | concentration of ammonia in the vapor | steam discharged | emitted from a tower top part can be raised. Therefore, a condensate containing high-concentration ammonium bicarbonate and ammonium carbonate is stored in the recovery liquid tank 8. Thereby, in the condensate, it can collect | recover as a collection | recovery liquid which the solid content which ammonium carbonate and ammonium bicarbonate precipitated mixed.

From the upper part of the recovered liquid tank 8, the exhaust gas containing unreacted carbon dioxide gas from which ammonia has been recovered is deodorized by the deodorizer 10 and released to the atmosphere. Of the gas released to the atmosphere, a part of the unreacted carbon dioxide is recirculated in the middle of the exhaust gas supply pipe 16.
Next, from the bottom of the stripping tower 2A, a deammonia liquid as a processing liquid is extracted by the second pump P2, and the heat exchanger 11 exchanges heat with the stock solution supplied to the ammonia removal device 2 as appropriate. Adjusted to temperature. Thereafter, the ammonia removal liquid is once stored in the relay tank 12 and then supplied to the methane fermentation tank 3 by the third pump P3.

The deammonification liquid supplied to the methane fermentation tank 3 is carried out in the methane fermentation tank 3 by a medium temperature fermentation treatment method at 35 to 38 ° C, but may be a high temperature fermentation treatment method at about 54 to 56 ° C. Moreover, PH in methane fermentation treatment is maintained at 8.0 to 8.5, and is operated at a volumetric load CODcr (chemical oxygen demand measured using potassium dichromate) 20 to 25 kg / m ³ / d. Is done. The generated digested gas stays in the gas reservoir formed in the upper part of the methane fermentation tank 3 to increase the internal pressure, and communicates with the draft tube to push up the digested liquid to the head tank disposed in the upper part.

  Digestion gas staying in the gas reservoir formed in the upper part of the methane fermentation tank 3 is discharged from the digestion gas discharge pipe at the pressure, supplied to the desulfurization tower 14 through the seal pot, and mixed in the digestion gas by the desulfurization tower 14. Hydrogen sulfide to be removed is removed and stored in the gas holder 15. The digestion gas stored in the gas holder 15 is used as fuel for the digestion gas boiler 4 and the digestion gas generator 5. In addition, the solid content concentration in the methane fermentation tank 3 is adjusted to be 4 wt% to 15 wt%.

  In the digestion gas boiler 4, the digestion gas after desulfurization is burned to generate water vapor. This steam is blown directly for heating the stock solution and gas supplied to the stripping tower 2A, or is used as steam for indirect heating. Note that the steam is supplied directly to the lower part of the storage tower 2A, is supplied to the stock solution after heat exchange, or a part of the deammonia liquid discharged from the stripping tower 2A is again supplied to the stripping tower 2A. When it is refluxed to the middle stage, it is supplied for direct heating of the liquid, such as being mixed in the refluxed deammonia solution, or for indirect heating as heat exchange at each location.

The exhaust gas containing carbon dioxide generated from the digestion gas boiler 4 and the digestion gas generator 5 at the time of combustion is pumped by the fourth pump P4 through the exhaust gas supply pipe 16 to the lower column and the bottom of the stripping tower 2A. . On the way, the flow rate indicating controller 17 controls the exhaust gas flow rate, while the CO ₂ concentration meter 18 measures the carbon dioxide concentration of the exhaust gas. When exhaust gas is excessively generated, a part (surplus) of the exhaust gas is released into the atmosphere from the upstream portion of the flow rate indicating controller 17 of the exhaust gas supply pipe 16.

  In this way, the livestock manure processing device is configured and the livestock manure is processed and operated, so that methane fermentation of livestock manure can be performed efficiently, and the livestock manure is disposed of as waste from nearby farmers, etc. Can be recovered as many effective processed materials such as livestock feed, fertilizer, and fuel gas that can be used in Japan, and discharge as waste can be minimized.

  In addition, carbon dioxide gas is blown from the bottom of the stripping tower 2A so that the heated nitrogenous organic waste is brought into gas-liquid contact to transfer ammonia nitrogen in the organic waste into the gas and gas-liquid contact. It can be recovered as a recovered liquid mainly composed of ammonium bicarbonate and ammonium carbonate by discharging the gas containing water vapor from the top of the tower accompanying the gas generated by the above, and cooling the gas containing these components with a cooler. . As a result, the ammonia deodorizing apparatus 10 can be made unnecessary after the steam is cooled from the stripping tower 2A.

In addition, the heat exchanger 11 is used to exchange heat between the organic waste supplied to the stripping tower 2A and the treatment liquid discharged from the bottom of the stripping tower 2A. Compared to the blowing method, the amount of water vapor can be reduced by about 15%.
Furthermore, in the ammonia removing device 2, the deammonia solution obtained by reducing ammonia nitrogen, which is an inhibitory factor in methane fermentation, to a concentration that does not affect methane fermentation is supplied to the methane fermentation tank 3. In the methane fermentation tank 3, digestion gas containing methane that is used as a fuel after being methane-fermented by the action of the methane-producing bacteria is recovered, and an efficient fermentation process is possible.

  Furthermore, the digestion gas generated from the methane fermentation tank 3 is combusted by the combustion devices 4, 5, and at that time, the exhaust gas containing carbon dioxide discharged from the combustion devices 4, 5 is sent to the stripping tower 2 A by the exhaust gas supply means 6. Supply. Thereby, the carbon dioxide gas supplied to the stripping tower 2 </ b> A of the ammonia removing device 2 can be obtained by effectively utilizing the digestion gas generated from the methane fermentation tank 3.

The exhaust gas containing carbon dioxide discharged from the combustion devices 4 and 5 is supplied to the stripping tower 2 </ b> A through the exhaust gas supply pipe 16. In the middle, the flow rate indicating controller 17 indicates and adjusts the flow rate of the exhaust gas, and the CO ₂ concentration meter 18 measures the carbon dioxide concentration of the exhaust gas. Thereby, carbon dioxide can be supplied efficiently.
Since the digestion gas before being supplied to the combustion devices 4 and 5 is desulfurized, generation of hydrogen sulfide and the like can be reduced and air pollution can be prevented.

Test Example An example of the results of heating livestock urine sewage, blowing carbon dioxide into an ammonia recovery device (stripping tower), and removing ammonia from the sewage is shown in FIG.
The processing conditions are 10 liter / hr of stock solution treatment, 4 g / liter of ammonia nitrogen concentration in stock solution, 600 liter / hr of gas blowing, 10% CO ₂ concentration in gas, stripping temperature of 80 ° C. At 85 ° C. and 90 ° C., the ammonia removal rates are 30.7%, 51.6%, and 75.7%. The recovered liquid ammonia nitrogen concentration was 2 to 8 moles / liter.
From the above results, when the liquid temperature (stripping temperature) was 90 ° C., the ammonia removal rate was about 76%, which was most preferable.

  INDUSTRIAL APPLICABILITY The present invention is useful for treating livestock manure such as cows, pigs, chickens, horses and sheep, organic waste such as food waste, or organic wastewater containing high concentration of ammonia nitrogen.

2 Ammonia removal device 2A Stripping tower 3 Methane fermentation tank 4 Digestion gas boiler (combustion device)
5 Digestion gas generator (combustion device)
6 Exhaust gas supply means 11 Heat exchanger 16 Exhaust gas supply pipe 17 Flow rate indicating controller 18 CO ₂ concentration meter

Claims (5)

A stripping tower is provided in which carbon dioxide gas is brought into contact with organic waste containing ammonia nitrogen, and ammonia nitrogen is separated from the organic waste to obtain a treatment liquid. Here, a stripping tower is provided at the upper stage of the stripping tower. Is provided with a means for supplying organic waste containing ammonia nitrogen, a means for injecting carbon dioxide gas is provided at the bottom of the tower, and ammonia nitrogen in the organic waste is accompanied by gas at the top of the tower. Discharge means for discharging is provided, and a cooler for cooling the steam containing ammonia discharged from the top of the stripping tower is provided downstream of the discharge means, and an ammonia component is further provided downstream of the cooler. A recovery liquid tank for recovering as a recovery liquid mainly composed of ammonium bicarbonate and ammonium carbonate is communicated. An ammonia removal apparatus according to claim 1 ;
A methane fermenter for supplying a treatment liquid obtained by the ammonia removing device according to claim 1 and methane-fermenting the organic waste from which the ammoniacal nitrogen has been separated, for decomposing the organic matter and recovering digestion gas; An organic waste processing apparatus comprising: A combustion apparatus for burning digestion gas generated from the methane fermentation tank;
The organic waste processing apparatus according to claim 2 , further comprising an exhaust gas supply unit configured to supply exhaust gas containing carbon dioxide exhausted from the combustion apparatus to the stripping tower. In the stripping tower, organic waste containing ammonia nitrogen is supplied to the upper stage of the tower, and carbon dioxide gas is blown from the lower stage of the tower to bring the organic waste and carbon dioxide into contact with each other. Nitrogen is separated to obtain a treatment solution, and ammonia nitrogen in organic waste is discharged along with the gas at the top of the tower, and ammonia is discharged downstream from the top of the stripping tower. A stripping step in which the steam containing the refrigerant is cooled and further the ammonia component is recovered downstream as a recovery liquid mainly composed of ammonium bicarbonate and ammonium carbonate ;
An organic waste comprising: a methane fermentation step of supplying the treatment liquid, subjecting the organic waste from which ammonia nitrogen has been separated to methane fermentation, and removing organic matter and recovering digestion gas How to handle things. The method for treating organic waste according to claim 4 , wherein the digestion gas is burned after being desulfurized, and the exhaust gas containing the carbon dioxide gas generated at that time is supplied to the stripping tower.

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