KR20020078538A - Process for treating a waste water containing a nitrous organic components - Google Patents

Abstract

PURPOSE: A wastewater treatment process for treating organics containing nitrogen is provided, which is characterized in that wastewater is hydrolyzed for decomposing organics into ammonia and carbon dioxide at near critical temperature and pressure of water. And hydrolyzed ammonia and carbon dioxide is recovered. CONSTITUTION: The process comprises (a) step for continuous inflow of pressurized wastewater (at 130 to 250 atm) and heating wastewater by heat exchange with treated water discharged from a reactor; (b) hydrolysis of organics of wastewater at 200-370 deg.C in the reactor; (c) cooling treated water discharged from the reactor by heat exchange with raw wastewater; (d) recovering ammonia at the upper part of a distillation tower, and recovering solution dissolved ammonia and carbon dioxide at the side of the distillation tower; and (e) discharging treated water at the lower part of the distillation tower.

Description

Process for treating a waste water containing a nitrous organic components

The present invention relates to a process for treating wastewater containing nitrogen-containing organic matters, and more particularly, to hydrolyzing wastewater including nitrogen-containing organic matters at a temperature and pressure state near the water critical point to convert the organic matter into ammonia and carbon dioxide. The present invention relates to a process for treating wastewater containing nitrogen and organic matters decomposing and recovering the hydrolyzed ammonia and carbon dioxide. In particular, the present invention is suitable for the treatment of high concentration, hardly decomposable nitrogen-containing organic waste liquid, which is difficult to be treated by biological treatment, and hydrolysis of organic matter at temperature and pressure near the critical point of water to convert ammonia and carbon dioxide, which are raw materials for urea synthesis. It relates to a near critical water hydrolysis process and ammonia recovery process to concentrate and recover. In the present invention, after decomposition of organic matter, ammonia and carbon dioxide are recovered and reused as raw materials for the urea synthesis process, and treated water can be reused as process water to essentially eliminate the generation of wastewater.

Representative by-products generated by industrialization include industrial wastewater and wastewater discharged from various industrial sites. Currently, the most widely used method of treating industrial wastewater and waste liquor is a biological treatment scheme, but is not suitable for the treatment of wastewater and waste liquor containing high concentrations of organic matter, hardly degradable organic matter or toxic organic matter. In particular, organic matter containing nitrogen has a lot of hardly decomposable substances, reduced to ammonia after decomposition, or oxidized to nitric acid, causing other problems in the ecosystem. As such, nitrogen dissolved in water acts as a nutrient source for microorganisms at low concentrations, but as the concentration increases, phytoplankton rapidly increases, depleting oxygen in the water, thereby acting as a threat to the survival of aquatic organisms. Excessive amounts of these nutrients are the cause of secondary pollution such as green algae and red tide. In addition, ammonia and nitrate ions are soluble in water and are toxic and cause destruction of aquatic organisms.

The nitrogen component contained in the wastewater can be roughly divided into three kinds of components such as nitrate nitrogen, ammonia nitrogen and organic nitrogen. The total content of these three components is called the total nitrogen content, and regulations on the total nitrogen content are carried out when the treated water is discharged.

Conventional methods for removing such nitrogen components include physical treatment and chemical treatment. Examples of the physical treatment include ion exchange, ammonia stripping, and the like. Chemical treatment includes ammonia removal using a chlorination reaction, biological removal, and incineration.

As a technique for removing nitrogen by ion exchange method, there is a selective ion exchange method for removing ammonia ions using a positive ion exchange resin or a nitrate ion using an anion exchange resin. Since the technique of treating waste liquid is not suitable, and especially when a high concentration of organic matter is contained, it is difficult to remove nitrogen and remove organic matter, so that organic nitrogen is difficult to be used alone in many wastewaters.

Ammonia stripping is a method of removing ammonia gas by contacting the air while maintaining the pH of the waste water at 10.5 to 11.5, but it takes a lot of time, and the investment costs such as the separation of water and ammonia gas in the gas state. In addition, nitrogen-containing organic matter other than the ammonia component cannot be treated, and organic matter contained in the wastewater cannot be removed.

Ammonia removal technology using the chlorination reaction, a chemical nitrogen removal method, can remove ammonia by adding chlorine to wastewater containing ammonia ions and converting it to nitrogen gas and hydrochloric acid. Problem, and the process of removing residual chlorine again has to be added, the removal of organic nitrogen is impossible,

Biological nitrogen removal method for removing organic matter and nitrogen using nitrifying microorganisms and denitrification microorganisms has been applied to a large amount of sewage treatment with the advantage that it can be treated at a low operating cost. However, while low concentrations of toxic chemicals such as domestic sewage and sewage are effective for removing nitrogen and organics, industrial wastewater contains a large amount of chemicals that are toxic to microorganisms and are discharged at high concentrations. There is a problem that the treatment is impossible because many, many treatment time is required, and is not suitable for high concentration industrial wastewater treatment. In addition, since the decomposition rate of microorganisms is not fast, the treatment time is very high, and the ability of microorganisms to cope with the change of wastewater concentration is low, so that it is appropriately changed to the rapidly changing wastewater concentration according to unstable conditions of chemical process such as chemical industry wastewater It does not have the disadvantage of being very difficult to do.

Incineration is the method most commonly used to treat high concentrations of organic wastewater or waste. However, when incinerated, nitrogen oxides (NOx) are generated due to high temperature, and there is a problem in that a large energy cost is required. In order to remove the nitrogen oxides generated again, an additional catalytic reactor has to be installed, which results in a large investment cost and operation constraints. In particular, the wastewater treatment method by incineration causes secondary pollution problems and is being replaced by new technologies in advanced countries due to high energy costs.

On the other hand, US Patent No. 4,341,640 discloses a method for hydrolyzing urea contained in wastewater generated in urea process of organic nitrogen-containing wastewater and recovering it as a mixed gas of ammonia, carbon dioxide and water. This method is a method of hydrolyzing wastewater containing urea at a temperature of 120 to 250 ° C. to decompose urea in wastewater into ammonia and carbon dioxide, and stripping to remove nitrogen from the wastewater. The hydrolysis reactor and stripping towers that remove ammonia and carbon dioxide from water after hydrolysis are integrally installed to perform decomposition and removal in a single tower. In addition, US Pat. Nos. 4,308,835 and 4,652,678 are other techniques developed to recover ammonia and carbon dioxide by hydrolyzing the wastewater, including urea, by temperature, and in US Pat. Nos. 4,168,299 and 4,220,635 using catalysts. The present invention relates to a method for increasing the hydrolysis efficiency. However, conventionally developed technologies are hydrolysis of urea.In addition to urea, nitrogen-containing organic matters contained in wastewater, such as melamine process, are not only biuret, triuret, amlide and urea. It has been found that it is difficult to treat wastewater containing hardly degradable substances such as melline and melamine.

As described above, the conventional technology of decomposing nitrogen-containing organic matters has a problem that the decomposition time is too long, such as biological treatment, or generates secondary pollutants such as incineration, or consumes a lot of energy. In order to solve this problem, a method of hydrolyzing urea wastewater has been developed to decompose and recover it with ammonia and carbon dioxide, which are raw materials for urea synthesis. However, although this technique can be suitably used to decompose low molecular weight nitrogenous organics such as urea, there are limitations to decomposing poorly decomposable nitrogenous organics such as wastewater from melamine processes.

Accordingly, an object of the present invention is to hydrolyze a hardly decomposable organic substance including nitrogen to decompose it into ammonia and carbon dioxide, and then separate and recover the ammonia and carbon dioxide from the treated water, and recycle the water back into process water to prevent environmental pollution, and waste water. To provide a process for the treatment of wastewater containing nitrogen-containing organics that can be recycled as a useful raw material.

Waste water treatment process of the present invention for achieving the above object is to hydrolyze waste water containing nitrogen-containing organic matter to decompose nitrogen-containing organic matter, recover the hydrolysis product ammonia and carbon dioxide, and process the water ammonia and carbon dioxide removed In the wastewater treatment process of recycling with water, while pressurizing the internal pressure to 130 to 250 atm to continuously introduce the wastewater into the heat exchanger, the wastewater introduced from the heat exchanger is heated by the treated water discharged from the reactor and simultaneously Cooling the treated water; Hydrolyzing the organic matter in the wastewater by raising the wastewater to a liquid phase region having an internal temperature of 200 to 370 ° C. or lower than a critical point of water; Hydrolyzing the organic material and then cooling the treated water discharged into the reactor by heat exchange with the incoming wastewater and then introducing the ammonia and carbon dioxide into a distillation column to recover the ammonia and carbon dioxide; And ammonia and carbon dioxide are introduced into the distillation column to recover ammonia from the top of the distillation column, and ammonia and carbon dioxide are recovered from the side of the distillation column as an aqueous solution dissolved in water. Draining the removed water.

1 is a process diagram schematically showing a process for treating wastewater containing nitrogen-containing organic matter according to the present invention.

※ Explanation of code about main part of drawing ※

A: wastewater pressurized pump B: heat exchanger

C: wastewater heater D: hydrolysis reactor

E: treated water cooler F: ammonia and carbon dioxide recovery tower

G: Recovered Ammonia Condenser H: Reflux Drum

I: Reboiler 10: Influent Wastewater

21: Feed Stream of Ammonia Recovery Tower

24: Recovered Ammonia (Top Stream)

25: Recovered Ammonia and Carbon Dioxide (Side Stream)

27: Bottom Stream

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

As described above, the conventional nitrogen-containing wastewater treatment technology does not decompose poorly decomposable nitrogen-containing organic matter like melamine process wastewater. In addition, even when decomposition, there is a problem that the secondary pollutant is discharged, or a lot of energy is consumed. Accordingly, the present invention efficiently decomposes an organic nitrogen component containing one or more from the group consisting of urea, biuret, triuret, amlide, amelin and melamine, reduces energy usage, and after hydrolysis A process was developed to recover wastewater containing nitrogen-containing organics that recovers ammonia and carbon dioxide, which are decomposition products, and reuses them as process materials.

This invention consists of the hydrolysis process of nitrogen-containing organic wastewater, and ammonia and a carbon dioxide recovery process. The hydrolysis process consists of a wastewater pressurization process, a heat exchanger, a heater, a reactor, a cooler, and the like.

The reactor is equipped with a heater to increase the organic hydrolysis efficiency and to operate at a temperature and pressure near the critical point of water, preferably 200 to 370 ° C. and 130 to 250 atmospheres, so as to be sufficiently hydrolyzed in a short time. It was able to exchange heat with the injected waste water to recover the high heat energy of the water sufficiently. In addition, in order to recover ammonia and carbon dioxide from the hydrolyzed treated water, a distillation column in which a stripper and an absorber are mixed is installed to recover and reuse the ammonia and carbon dioxide, and the treated water is recycled to process water.

FIG. 1 briefly illustrates a nitrogen-containing organic waste liquid treatment process in which the nitrogen-containing organic waste liquid developed in the present invention is hydrolyzed and treated to remove and recover the ammonia and carbon dioxide components as decomposition products from the treated water. The waste liquid 10 containing organic nitrogen is injected into the heat exchanger B after raising to an operating pressure near the critical pressure (218 atm) of water through the high-pressure injection pump A (11). The pH of the wastewater is preferably 7 or more because the hydroxide ion concentration becomes high, which can increase the hydrolysis reaction. The organic nitrogen component may be a product, raw material or product contained in the wastewater generated in the urea process or melamine process, such as urea, biuret, triuret, amide, ameline, melamine, and / or cyanuric acid. It is a byproduct component.

The heat exchanger (B) may perform the function of cooling the high-temperature treated water 14 discharged from the reactor (D) again with the waste liquid supplied to the reactor (D), and the waste liquid flowing from the pump (A) is heated. It is designed to be. The waste liquor 12 heated primarily in the heat exchanger B is heated in the waste liquor heater C to a hydrolysis reaction temperature and then injected into the bottom of the reactor D (13). Reactor D is operated at 218 atm and 374 ° C., preferably at 130 to 250 atm and 200 to 370 ° C., which is the critical point of water, and is operated in the liquid phase to increase the decomposition efficiency per reactor D. If the temperature is less than 200 ℃ hydrolysis reaction rate is low, if the temperature exceeds 370 ℃ the reaction solution is in a supercritical state, the density is sharply reduced and the reactor volume has to be increased, if the air pressure is less than 130 atm reaction The liquid vaporizes so that the gas and the liquid coexist and the average reaction liquid density decreases. When the pressure exceeds 250 atmospheres, the energy efficiency decreases.

The treated water from which the organic matter is decomposed is discharged out of the reactor by a discharge pipe installed at the top of the reactor (D) (14). The discharged waste liquid is cooled in the heat exchanger (B) as described above (15), and then adjusted to the injection temperature of the ammonia recovery tower (F) in the treated water cooler (E) and then injected into the ammonia recovery tower (F). (21). The injection temperature is preferably 60 ° C. to 100 ° C. because it is similar to the temperature range of the inlet point of the distillation column.

In the ammonia recovery tower F, low-boiling materials such as ammonia and carbon dioxide contained in the treated water are raised to the upper portion, and treated water 27 from which ammonia and carbon dioxide is removed is discharged through the line 26 at the lower portion. More specifically, the internal pressure of the distillation column is maintained at 18 to 21 atm, the internal temperature of the top of the distillation column is maintained at 50 ℃ to 60 ℃ or less, the internal temperature of the distillation column side discharged water is maintained at 100 ℃ to 150 ℃ And, the internal temperature of the bottom of the distillation column is maintained at 180 ℃ to 220 ℃.

Effluent (27) from which ammonia, carbon dioxide and nitrogen-containing organic matters have been removed can be recycled to process water, and when the wastewater generated in the melamine process is treated, controlling the decomposition rate of the melamine component as a product allows the melamine component to remain in the effluent to recover melamine. Can be sent to the process to increase the recovery of the product. On the other hand, since ammonia and carbon dioxide aqueous solutions form an azeotropic point, it is very difficult to concentrate only ammonia. Therefore, the ammonia was injected from the upper part of the recovery tower and operated while maintaining the excess ammonia area so that only pure ammonia could be recovered (22 and 23) to the upper part of the tower. The recovered ammonia can be used as part of the reflux of the recovery tower and part of it as a product for recycling. Meanwhile, an aqueous solution near the azeotropic point of ammonia and carbon dioxide is discharged through an outlet on the side of the tower, which is sent to the urea process and recycled as a urea synthesis material.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

Example 1

Hydrolysis of Urea Aqueous Solution

Hydrolysis was performed by dissolving 1000 ppm of urea in 11% aqueous ammonia. The pressure was fixed at 3700 psig, the hydrolysis reaction was carried out while changing the temperature and the reactor residence time, and the degree of hydrolysis of the urea was measured by measuring the concentration of urea remaining after the treatment. Table 1 below shows the conversion of urea at each temperature and residence time change.

Hydrolysis Results of Urea Reaction temperature (℃) Residence time (sec) Urea Concentration (mg / L) % Conversion 200 7 819 18.1 200 10 745 25.5 200 20 698 30.2 220 7 730 27.0 220 10 693 30.7 220 20 502 49.8 240 7 580 42.0 240 10 437 56.3 240 20 237 76.3 260 7 370 63.0 260 10 165 83.5 260 20 22 97.8

Example 2

Hydrolysis of Biuret Aqueous Solution

Hydrolysis was performed by dissolving 1000 ppm of biuret in 11% aqueous ammonia. The pressure was fixed at 3700 psig, the hydrolysis reaction was carried out while changing the temperature and the reactor residence time, and the degree of hydrolysis of the biuret was measured by measuring the concentration of the biuret remaining after the treatment. Table 2 below shows the conversion rate of the biuret according to the change of temperature and residence time.

Hydrolysis Results of Biuret Reaction temperature (℃) Residence time (sec) Biuret Concentration (mg / L) % Conversion 200 7 860 14.0 200 10 795 20.5 200 20 640 36.0 220 7 685 31.5 220 10 602 39.8 220 20 405 59.5 240 7 608 39.2 240 10 435 56.5 240 20 180 82.0 260 7 405 59.5 260 10 204 79.6 260 20 8 99.2

Example 3

Hydrolysis of Triuret Aqueous Solution

Hydrolysis was carried out by dissolving 1000 ppm of triuret in 11% aqueous ammonia. The pressure was fixed at 3700 psig, the hydrolysis reaction was carried out while varying the temperature and the reactor residence time, and the degree of triuret hydrolysis was measured by measuring the concentration of the triuret remaining after the treatment. Table 3 below shows the conversion rate of Triuret according to the change of temperature and residence time.

Hydrolysis Results of Triuret Reaction temperature (℃) Residence time (sec) Triuret Concentration (mg / L) % Conversion 200 7 840 16.0 200 10 775 22.5 200 20 650 35.0 220 7 685 31.5 220 10 593 40.7 220 20 398 60.2 240 7 608 39.2 240 10 413 58.7 240 20 110 89.0 260 7 387 61.3 260 10 175 82.5 260 20 5 99.5

Example 4

Hydrolysis of Amide and Amelin Solution

Hydrolysis was performed by dissolving a 1000 ppm mixture of amide and amelin in an aqueous 11% ammonia solution. The pressure was fixed at 3700 psig, and the hydrolysis reaction was carried out while changing the temperature and the residence time of the reactor. It was. Table 4 shows the concentrations and conversion rates of the amlides and ammelles with the change of temperature and residence time.

Hydrolysis Results of Amide and Amelin Mixtures Reaction temperature (℃) Residence time (sec) Amide (mg / L) % Conversion Amelin (mg / L) % Conversion 200 7 840 16.0 840 16.0 200 10 775 22.5 775 22.5 200 20 650 35.0 650 35.0 220 7 685 31.5 685 31.5 220 10 593 40.7 593 40.7 220 20 398 60.2 398 60.2 240 7 608 39.2 608 39.2 240 10 413 58.7 413 58.7 240 20 110 89.0 110 89.0 260 7 387 61.3 387 61.3 260 10 175 82.5 175 82.5 260 20 5 99.5 5 99.5

Example 5

Hydrolysis of Mixed Wastewater

In the melamine production process, the wastewater discharged after crystallization and recovery of the melamine product was hydrolyzed. Wastewater discharged from the crystallization process of melamine products cannot be dissolved and recovered without being determined in the crystallization process such as urea, biuret, amlide, amelline, etc. Contains melamine, a product not found. In Table 5, the composition of the substances contained in the wastewater and the concentrations of the substances contained in the treated water after hydrolyzing and treating the wastewater were compared. In addition, as a result of converting the concentration of the nitrogen component (Organic Nitrogen) contained in these organic substances, it can be seen that more than 99% of the nitrogen component can be removed. It can be seen that the decomposition efficiency increases with increasing temperature. During hydrolysis, process operating conditions were maintained at a pressure of 3400 psig and a residence time of 15 minutes.

Hydrolysis Results of Melamine Process Wastewater 1 Concentration (mg / L) Temperature (℃) Organic Nitrogen (mg / L) Element Bayurette Amide Amelin Melamine Wastewater 900.0 70.0 990.0 1710.0 7700.0 - 6957.5 Treatment water 1 0.0 0.0 0.0 0.1 43.4 350 29.0 Treatment water 2 0.0 0.0 0.0 0.8 79.0 340 53.1 Treatment water 3 0.0 0.0 0.0 1.3 136.0 330 91.4 Treatment water 4 0.0 0.0 3.0 12.0 250.0 300 174.6

Example 6

Hydrolysis of Mixed Wastewater

Wastewater having different concentrations generated in the melamine production process was hydrolyzed in the apparatus of FIG. 1 by varying the temperature, pressure, and residence time. Table 6 compares the composition of the substances in the wastewater and the concentrations of the substances in the treated water after hydrolyzing and treating the wastewater. As shown in Table 6, it can be seen that the decomposition efficiency increases with increasing temperature and reactor residence time.

Hydrolysis result 2 of melamine process wastewater Concentration (mg / L) Temperature (℃) Pressure (psig) Residence time (min) Element Bayurette Amide Amelin Melamine Wastewater 400.0 70.0 740.0 1590.0 4050.0 - - - Treatment water 1 0.0 0.0 0.0 0.0 13.2 370 3700 15 Treatment water 2 0.0 0.0 2.0 1.4 123.2 350 3700 10 Treatment water 3 5.0 0.0 5.9 10.8 822.6 350 3700 5 Treatment water 4 70.0 0.0 7.6 5.5 297.1 350 2000 2 Treatment water 5 40.0 0.0 2.8 1.2 78.7 350 2000 3 Treatment water 6 120.0 444.3 9.5 33.7 1653.0 350 2000 1/3 Treated water7 0.0 0.0 0.0 3.1 295.8 300 3140 15 Treatment water 8 0.0 0.0 0.0 4.8 373.5 300 3140 10

Example 7

Recovery of Ammonia and Carbon Dioxide from Treated Water

Waste water generated in the melamine production process was hydrolyzed and decomposed, and ammonia and carbon dioxide were recovered in the ammonia recovery tower. The temperature of the hydrolysis reactor was maintained at 330 ° C., the pressure was 3200 psig, and the reactor residence time was continuously hydrolyzed while maintaining an average of 12 minutes. The ammonia was recovered while operating at 200 ° C. and a pressure of 276 psig.

Table 7 shows the measurement of the flow rate and composition of the composition of the influent and the recovery of the ammonia recovery tower (24 of FIG. 1), the side stream (25 of FIG. 1), and the effluent (27 of FIG. 1). .

Recovery of ammonia and carbon dioxide after hydrolysis Stream name Flow rate (kg / hr) Concentration (wt%) ammonia carbon dioxide water Melamine Injection (21 in FIG. 1) 29000 14.07 2.13 83.78 0.02 Top stream (24 of FIG. 1) 3111 100 0 0 0 Side stream (25 of FIG. 1) 3000 32.3 20.6 47.1 0 Bottom stream (27 in FIG. 1) 22889 0.0 0.0 99.97 0.03

Comparative Example 1

Effluent before and after wastewater treatment

After hydrolysis using the wastewater generated in the melamine production process, the ammonia and carbon dioxide were recovered in the ammonia recovery tower. In Table 8, the wastewater was hydrolyzed by the present invention to recover ammonia and carbon dioxide (Example 7), and to compare the composition of the effluent. As can be seen in Table 8, many nitrogen-containing organic substances that were previously discharged into the effluent are recovered as ammonia and carbon dioxide, and more than 99% of the organic substances remaining in the effluent are removed. In addition, it can be seen that the recovery of ammonia increased by 12.6% from 2,762kg / hr to 3,111kg / hr before treatment.

Comparison of Ammonia Recovery and Effluent Components Before and After Wastewater Treatment Before treatment After treatment Feed Stream Upstream Sidestream Downstream Injection stream Upstream Sidestream Downstream Flow rate (kg / hr) 31000 2762 2600 25638 29000 3111 3000 22889 Concentration (wt%) water 84.9 0.0 45.4 98.10 83.78 0.0 47.10 99.97 carbon dioxide 0.6 0.0 7.2 0.0 2.13 0.0 20.6 0.0 ammonia 12.9 100.0 47.4 Trace 14.07 100.0 32.3 Trace Amide 0.13 0.0 0.0 0.16 0.0 0.0 0.0 0.0 Amelin 0.16 0.0 0.0 0.19 0.0 0.0 0.0 0.0 Melamine 0.96 0.0 0.0 1.16 0.02 0.0 0.0 0.03 Element 0.32 0.0 0.0 0.39 0.0 0.0 0.0 0.0

As described above, the present invention is to decompose organic matter in wastewater containing nitrogen-containing organic matter by hydrolysis reaction at temperature and pressure conditions near the critical point to decompose the ammonia and carbon dioxide, and then recover the decomposed ammonia and carbon dioxide. It relates to a process for recycling into raw materials. In the present invention, the nitrogen-containing organic matter contained in the waste water is hydrolyzed more than 99% to recycle to ammonia and carbon dioxide to recycle the material that was discharged as a waste, the waste water from which the organic contaminant including nitrogen is removed is recycled back to the process water I could do it. In particular, the present invention is applied to a process for discharging a large amount of nitrogen-containing organic matter, such as melamine process and urea process, thereby fundamentally preventing the generation of nitrogen-containing organic waste and wastewater, and decomposing pollutants and recycling them as raw materials. .

Claims (7)

In a wastewater treatment process in which wastewater containing nitrogen-containing organic matter is hydrolyzed to decompose nitrogen-containing organic matter, and then ammonia and carbon dioxide, which are hydrolysis products, are recovered, and the water from which the ammonia and carbon dioxide has been removed is recycled to process water. Pressurizing the internal pressure to 130 to 250 atm to continuously flow the wastewater into the heat exchanger, while heating the wastewater flowing from the heat exchanger by the treated water discharged from the reactor, and simultaneously cooling the treated water; Hydrolyzing the organic matter in the wastewater by raising the wastewater to a liquid region having an internal temperature of 200 to 370 ° C. or less below a critical point of water; Hydrolyzing the organic material and then cooling the treated water discharged into the reactor by heat exchange with the incoming wastewater and then introducing the ammonia and carbon dioxide into a distillation column to recover the ammonia and carbon dioxide; And The treated water including ammonia and carbon dioxide is introduced into the distillation column to recover ammonia from the upper part of the distillation column, and recover the ammonia and carbon dioxide from the aqueous solution dissolved in water from the side of the distillation column, and remove the ammonia and carbon dioxide from the lower part of the distillation column. A wastewater treatment process comprising a nitrogen-containing organic material, characterized in that it comprises the step of discharging the water. The wastewater treatment process according to claim 1, wherein the pH of the influent wastewater is 7 or more. According to claim 1, wherein the distillation column inlet step is hydrolyzed nitrogen-containing organic material in the liquid state to remove the ammonia and carbon dioxide produced by decomposition of the nitrogen-containing organic material in water dissolved in water in the hydrolysis process after the internal temperature is 60 Waste water treatment process characterized in that the introduction into a distillation column for recovering ammonia and carbon dioxide by adjusting to 100 ℃. The waste water according to any one of claims 1 to 3, wherein the nitrogen-containing organic material is selected from the group consisting of urea, biuret, triuret, amlide, amelin and melamine. Treatment process. According to claim 1 or 3, wherein the internal pressure of the distillation column is maintained at 18 to 21 atm, the internal temperature of the top of the distillation column is maintained at 50 ℃ to 60 ℃ or less, the internal temperature of the distillation column side discharge water is 100 ℃ To 150 ° C., and the internal temperature of the lower part of the distillation column is maintained at 180 ° C. to 220 ° C. 2. The wastewater treatment process according to claim 1, wherein ammonia is injected into the upper part of the distillation column and operated while maintaining the excess ammonia in the region to recover pure ammonia to the upper part of the column. The wastewater treatment process according to claim 1, wherein the discharged water from the lower part of the distillation column from which the ammonia and carbon dioxide are removed is recycled to the process water.