EP1768933A1

EP1768933A1 - Method and device for separating magnesium-ammonium-phosphate (map) from waste water

Info

Publication number: EP1768933A1
Application number: EP05760947A
Authority: EP
Inventors: Oliver Christ; Simone Meuler; Franz Bischof
Original assignee: Hans Huber AG Maschine und Anlagenbau
Current assignee: Huber SE
Priority date: 2004-07-08
Filing date: 2005-07-08
Publication date: 2007-04-04
Also published as: WO2006005733A1; DE102004033310A1; WO2006005733A8

Abstract

The invention relates to a method for separating magnesium-ammonium-phosphate (MAP) (16) from waste water by adding a precipitant (5) to a container (2), the waste water being mixed with the precipitant (5). Said waste water is essentially undiluted urine separated from faeces and other solid materials. Once the process time is finished, the precipitate formed (9) and a depleted yellow water (8) are discontinuously separated from each other. The invention also relates to a device for separating magnesium-ammonium-phosphate (MAP) (16) from waste water by adding a precipitant (5) to a container (2), said device comprising a supply (1, 4) for undiluted waste water separated from faeces, and for the precipitant (5). Furthermore, the container (2) comprises a discharge line (18, 19) for the precipitate (9) and/or for the depleted yellow water (8).

Description

Process and apparatus for separating magnesium ammonium phosphate MAP from wastewater

The present invention relates to a method and apparatus for separating magnesium ammonium phosphate (MAP) from wastewater by adding a precipitant in a container.

In addition to organic substances, wastewater and especially yellow water contains almost all of the valuable soluble nutrients such as nitrogen, phosphorus, potassium and others. Yellow water, essentially urine, is produced in relatively small amounts, but mainly contains the nutrients phosphorus and nitrogen in large quantities. So far, the yellow water is detected together with other wastewater and rainwater in a sewer system and anschlie¬ ßend freed in a central sewage treatment plant largely of harmful and nutrients. In order to avoid contamination of the aquatic environment by over-fertilization, the nutrients, phosphorus and nitrogen, are removed from the wastewater in a high expenditure of energy, and in some cases using chemicals, in today's conventional wastewater treatment systems, without supplying them to further use.

As methods for the purification of wastewater in terms of nitrogen and phosphorus elimination, various methods, for. B. biological Verfah ren or Knickpunktchlorung known. However, these processes only provide the desired cleaning performance and are not suitable for the re-hydration of nutrients. Recovery of phosphates is possible by means of different precipitation reactions; by precipitation of magnesium ammonium phosphate (MAP, MgNH ₄ PO ₄ ), an effective return of obtained phosphorus and nitrogen, since both nutrients can be simul¬ tan eliminated.

Such a process for large-scale elimination of ammonium and phosphate from industrial wastewater is known for example from DE 37 32 896 A1. It is proposed to substantially eliminate ammonia and phosphate from wastewater by adding magnesium salt or magnesium oxide. The degree of elimination can be controlled by the added amounts of magnesium or phosphate so that the content of ammonium or the content of phosphate is minimized. Magnesium is added according to the ammonia and phosphate content of the waste water until a certain stoichiometric ratio is reached. The pH is adjusted to a value between 7 and 10, so that the salt crystallizes magnesium ammonium phosphate MAP. The separation of the salt can be carried out by sedimentation or centrifugation. The MAP obtained from the precipitation can be made available as fertilizer. However, MAP precipitation from yellow water is limited by the availability of phosphate, so that optimization of MAP precipitation is designed for phosphorus elimination. In particular, in the treatment of urine, in which phosphate is present in much smaller amounts than ammonium, no remarkable ammonium precipitation (NH ₄ ⁺ ) and thus nitrogen elimination are to be expected with an optimal stoichiometric reaction. Higher NH ₄ ⁺ precipitation could be achieved only by an additional source of phosphate, which means increased use of chemicals.

The object of the present invention is to propose a method for separating MAP from wastewater, which is suitable for the treatment of wastewaters, in particular of urine, on a smaller scale and, in addition to phosphorus, also provides nitrogen in a form usable as fertilizer , The object is achieved with a method and a device according to the independent claims.

In a process according to the invention, magnesium ammonium phosphate is separated from wastewater with the addition of a precipitant in a container. The effluent is essentially undiluted urine liberated from faeces and other solids. In the container or prior to introduction into the container, the urine is mixed with the precipitant. For example, magnesium oxide, magnesium hydroxide, magnesium carbonate or the like can be used as precipitating agents. Since the wastewater is essentially undiluted urine, which is not mixed with rinsing water and other waste waters, the nutrients phosphorus and nitrogen are present in a process-technically favorable concentration, so that nutrient recovery is possible in a very economical manner. The addition of another phosphate source is not required. The resulting precipitation product and the depleted yellow water are then separated from each other after completion of a process time discontinuously. The discontinuous separation allows a sufficiently long reaction time for precipitation of the MAP and the formation of larger crystals. In addition, it includes the possibility of separating the precipitate and the remaining yellow water in a particularly simple manner from one another by sedimentation in the precipitation reactor. This is particularly advantageous for smaller, de¬ central systems, since the space required by such a system can be kept low. The precipitated product can then be further used as fertilizer. The depleted yellow water becomes, u. U. after a further treatment stage, for example, the Ka¬ nalisation supplied. A complex phosphorus and nitrogen elimination is no longer necessary in the subsequent wastewater treatment. It is particularly advantageous here if the urine is obtained from a Separationstoi¬ lette or from a urinal. The use of Separationstoi¬ letten not only allows collection of urine in highly concentrated form and thus almost complete nutrient recovery, but is also useful in terms of economical use of water.

It is particularly advantageous if the urine is adjusted to a pH of about 9 before mixing with the precipitating agent. The MAP precipitation reaction is highly dependent on the pH in the solution. In general, the urine has an acidic pH between 5.0 and 6.4. If the urine is stored for several days, the urea contained in the urine decomposes by enzyme action to form ammonia (NH ₃ ) and carbon dioxide. The release of ammonia shifts the pH to the alkaline range. The release of ammonia can be achieved not only by storage for several days but also by heating. Likewise, the required pH can, however, also be adjusted by the addition of lye. An alkaline pH of about 9 causes an optimal concentration of ammonium or ammonia in the solution for MAP precipitation.

Furthermore, it is advantageous if the urine and the precipitant are stirred for mixing. The intensive mixing of precipitant and yellow water favors the formation of insoluble compounds of the precipitate. In particular, it is advantageous if, after the first intensive mixing, only little turbulence occurs during the crystallization phase, so that the growth of larger crystals is also possible.

The precipitation product and depleted yellow water are preferably separated after a process time of at least 10 minutes. The process time includes the reaction time during which the actual precipitation and the formation of larger particles of the MAP take place. In addition, during the process time, the separation of the precipitated product from the depleted yellow water instead. The separation can be carried out by expressing, filtering, sedimentation or other methods, so that the separation process considerably influences the process time. In a separation by sedimentation, the process time can therefore be several hours.

In an advantageous development of the invention, it is proposed that the precipitate remains several times in the container for the separation of urine and / or precipitant added again. As a result of the discontinuous separation, the precipitate is present at the end of the process time as a suspension in the lower region of the container. The supernatant treated urine is drained from the container and can then be further treated while the precipitate remains in the container. If urine and / or precipitant are again added to the container, the already precipitated MAP can continue to react in the next precipitation reaction and provide nucleation nuclei for the next crystallization, so that even larger particles can be grown. The remaining in the container suspension is thus concentrated with each processing operation. After the last processing run, for example at the end of a day, the concentrated suspension is then removed from the container.

Preferably, the precipitate is dehydrated and / or dried after the final separation of depleted yellow water. The suspension remaining in the container is dried by an integrated drying process. Such a drying process makes it possible to recover the precipitate MAP in powder form. Likewise, however, a filtering of the suspension and subsequent drying outside the container is possible.

Furthermore, it is advantageous if the separated from the precipitated product depleted yellow water is passed into a reservoir. It is particularly advantageous if the collected in the storage container abge- richer yellow water is heated to about 50 ⁰ C. The MAP precipitation is limited by the content of phosphate in urine, so that even after the precipitation even larger amounts of ammonium or ammonia are in the Ab¬ water. In a further process step, ammonia can be removed from the fused yellow water. For this purpose, it is necessary that the ammonia is present in gaseous form in the waste water, which is favored by an increase in temperature. A temperature of 50 ^° C. has proven to be optimal for the next process step. In particular, when heating the depleted yellow water in the storage tank for about two hours, an advantageous uniform heating is achieved. However, the depleted yellow water can also be returned to the tank for a further precipitation reaction, thereby achieving further depletion.

Preferably, the depleted yellow water is promoted after heating in a stripping column, where it is removed from the ammonia still contained in it. It proves to be advantageous if the yellow water trickles in the stripping column in countercurrent flow over packing. The ammonia is in this case removed from the liquid and accumulates in the stripping air. The fillers in this case allow a uniform distribution of the yellow water in the column and provide a large surface for Stoff¬ exchange available.

It is likewise advantageous if the yellow water from the bottom of the stripping column is fed to a further treatment and / or to the feed tank. If the yellow water is returned to the storage tank and the stripping column passes through again, residual amounts of ammonia still remaining can be removed. After a predetermined number of further passes through the stripping column, the depleted yellow water is discharged from the circuit. In a preferred embodiment of the invention, the air is heated prior to entering the stripping column and / or cooled after leaving the stripping column. By heating the air before entering the stripping column, an optimum process temperature for the ammonia absorption is achieved, which increases the efficiency of the stripping process. If the air is circulated and subjected in a further process to a chemical scrubbing, cooling the air after it leaves the stripping column is advantageous for the following process step.

In a further advantageous form of the invention, the air-ammonia mixture leaving the stripping column is washed chemically in a further column. By means of the chemical scrubbing, the stripping gas charged with NH ₃ can be purified of ammonia and recirculated to the stripping column in the circuit. It has proved to be particularly advantageous when the air-ammonia mixture is washed with water or acid, in particular sulfuric acid, nitric acid or phosphoric acid. In this case, the stripping air loaded with ammonia is flowed through in countercurrent, for example, sulfuric acid in a regeneration column. The ammonia is removed from the air and combines with the sulfate of sulfuric acid to form ammonium sulfate, which can be used in the fertilizer production in agriculture or industry.

In a device according to the present invention for separating magnesium ammonium phosphate from waste water by adding precipitant to the waste water in a container, the container comprises a supply of substantially undiluted urine separated from faeces and solids and a precipitating agent. Furthermore, the container has a discharge line for a precipitated product and / or for depleted yellow water. The wastewater is passed in batches into the container and via the feed for the precipitating agent a corresponding amount of precipitating agent is metered in, so that the precipitation takes place discontinuously. The urine and the precipitant may also be mixed before being introduced into the container and ne common line are introduced into the container. Advantageously, the essentially undiluted urine is obtained from a rationing toilet. At the end of the process time, the separated precipitate product is removed via a discharge line. The depleted urine can be passed through a further discharge line in the reservoir. Likewise, however, it is also possible first to discharge precipitate and yellow water via a common line and to separate it outside the container.

Furthermore, it is advantageous if the container is associated with a mixing device for mixing urine and precipitant. The Mischeinrich¬ device, for example, a stirrer ensures after addition of the precipitant in the container for a thorough mixing with the urine. However, the mixing of the urine with the precipitant may also be done outside the container prior to introduction into the container.

In a further advantageous embodiment of the invention, the discharge line for the precipitated product is assigned a drying device. In the container s? the precipitate MAP is present as a highly concentrated suspension with a certain content of residual water. By drying the residual water is removed and the precipitate MAP can be removed directly in powder form and recycled as fertilizer. The drying device may in this case be integrated in the container or be located outside the container. It is likewise advantageous if the drying ^; Nungseinrichtung has a filter bag. After the suspension has been drained, the precipitate MAP can be filtered out of the suspension via the filter bag.

In a further development of the invention, it is proposed that the discharge lines for the precipitated product and / or for the depleted yellow water in a

Open the storage container. After the precipitation has taken place in the container, the depleted yellow water is introduced via a discharge line into the from where it is fed to the stripping column to remove ammonia. The residual water from the suspension can also be supplied via a further or else via the same line to the feed tank and a subsequent stripping.

In a particularly advantageous embodiment of the invention, a heater is assigned to the feed tank, so that the process for the stripping neces sary process temperature of about 5O ⁰ C achieved in a simple manner can wer¬.

Advantageously, the feed tank is connected by means of a conduit with a stripping column. The depleted-β urine from the storage tank can be fed via this line to the stripping column, where it is deprived of residues of ammonia, so that the nitrogen can also be recovered in optimum form from the urine.

In one embodiment of the invention it is provided that in the Strippko¬ lonne packing are arranged, trickles over which the depleted yellow water from top to bottom. The packing improves the mass transfer between the yellow water and the stripping air by providing a large phase interface. For the mass transfer, it is also advantageous if the stripping column can be flowed through from bottom to top, so that the yellow water is flowed through in countercurrent.

It has also proven to be particularly advantageous if a line to a further treatment device and / or the storage container is arranged at the bottom of the stripping column. If the depleted urine is again supplied to the feed tank after flowing through the stripping column, possibly existing residual amounts of nitrogen can be removed in a further stripping process. It is particularly advantageous if a heating is arranged for the air before entry into the stripping column and / or cooling after leaving the stripping column. The air can hereby be brought by the heater to an optimum process temperature for the ammonia absorption before entering the stripping column. If a chemical washing of the stripping air is carried out after the stripping process, it is advantageous to cool the stripping air laden with ammonia after it has left the stripping column.

If the stripping column for the air-ammonia mixture emerging from the stripping column is connected to a further column for chemical washing, the nitrogen can also be recovered from the air and fed to a further use. In the case of chemical scrubbing, the air can be washed in acidic solutions, with, for example, sulfuric acid flowing through the air in countercurrent. In this case, the air is removed from the ammonia, and ammonium sulfate is obtained as the end product. The formation of ammonium salt solutions in the chemical scrubbing is facilitated by the cooling of the air. Ammonium sulfate can be used in agriculture or industry, for example as a fertilizer additive.

Further advantages of the invention are described in connection with the following embodiment.

FIG. 1 shows a schematic representation of a device according to the invention and a corresponding method for the treatment of yellow water.

In a process according to the invention for the treatment of wastewater, the wastewater passes in succession through a precipitation reactor 10 for the recovery of magnesium ammonium phosphate MAP and a stripping column 20 for the removal of nitrogen from the wastewater. The stripping air is subsequently cleaned in a regeneration column 30 of ammonia. The Wastewater is a substantially undiluted urine, for example, from a separation toilet containing phosphate and ammonium in high concentrations. The precipitation of the MAP takes place discontinuously, it being possible to treat in each case about 50 l of urine in each case. The design of the process is adjusted to an accumulating urine volume of 200 l daily.

The wastewater to be treated is passed via a feed 1 into the container 2, in which the precipitation reaction takes place. Via a further supply line 4, a precipitant 5 is introduced into the container 2. The feeding and metering of the precipitating agent 5 is carried out in the illustrated example in a fully automated manner via a microdosing device 3. Magnesium oxide is used as precipitant 5, since it has a high precipitation efficiency. As a precipitation product 9, magnesium ammonium phosphate MAP is formed, which in this embodiment is separated from the depleted yellow water 8 by sedimentation and settles at the bottom of the container 2. During the feeding, the urine is mixed with the precipitating agent 5 by a mixing device 7, in the example shown a stirrer 11. It is advantageous in this case if the rotational speed of the stirrer 11 can be regulated. When dosing the precipitant 5, a good mixing can be ensured at a high [rotational speed], while a lower rotational speed during the crystallization phase permits optimum growth of the MAP crystals. However, other mixing devices 7 are also conceivable. Also, the mixing device 7 may be arranged outside of the container 2, so that only the separation of the precipitation product 9 takes place in the container 2.

After an undurchmischten sedimentation of about 4 hours, the supernatant is drained from depleted yellow water 8 via a discharge line 19 into a storage tank 13 and preheated there for the following stripping to about 50 ⁰ C. The precipitation product 9 remains in the lower region at the bottom of the container 2 and forms nucleation nuclei for the next reaction. At the end of the last course of treatment one day, with a daily urine volume of 200 l, ie after four Lungprozeßen, the precipitation product 9, which is present as a suspension at the bottom of the container 2, drained via a further discharge line 12. The discharge of the depleted yellow water 8 and the discharge of Fällungspro¬ product 9 are controlled by solenoid valves 6. The precipitated product 9 then passes through a drying device 15, where the residual water still contained in the suspension is separated off. Separation may be by filtration, pressing or otherwise. After drying, powdered MAP 16 can be removed from the drying device 15. Likewise, however, only the filtration can be carried out in the precipitation reactor 10 and the drying carried out externally. The filtered geIb water 17 is also passed into the reservoir 13. It is also possible to discharge the precipitation product 9 and the depleted yellow water 8 over the same line. The separation can take place here before draining in the container 2 or even after draining outside the container 2.

The depleted yellow water 14 preheated for the stripping is subsequently passed via a line 28 into a stripping column 20. A Rück¬ guide 18 in the container 2 is also possible. In a precipitation process, about 70% to 95% of the phosphorus precipitated, so that by the Rück¬ guide 18, the precipitation rate can be increased.

In the stripping column 20 packing 22 are arranged to increase the surface in bulk. The packing 22 have a lattice-like structure, so that it does not come to Ver¬ stuffs even in a precipitation of solids. For stripping the ammonia from the depleted yellow water 14, it is necessary that this is present in gaseous form, which is favored by a temperature increase to about 50 ⁰ C. For this purpose, the receiver container 13 is heated accordingly by a heater (not shown here). The air 23 is also preheated by a heater 24 for stripping and compressed in a compressor 25. The depleted yellow water 14 passes through the stripping column 20 from top to bottom, during which in the opposite direction, compressed air 23 flows through it. As a result, continuous desorption takes place in the stripping column 20, ie the air 23 constantly comes into contact with highly concentrated yellow water 14 on its way through the packing 22 from below to absorb ammonia, while the depleted yellow water 14 desorbs ammonia continuously. In the stripping column 20, a nitrogen elimination of about 90% is achieved. The phosphorus-and-nitrogen-depleted liquid 26 can be recycled several times into the feed tank 13 for renewed stripping, so that an even higher nitrogen elimination is achieved. After a predetermined number of passes, the depleted liquid 26 is discharged via a siphon 27 in order to ensure trouble-free guidance of the compressed air 23. The depleted liquid 26 can then be fed to the sewer or to another purification stage.

The ammonia-laden air 21 is then drawn off the ammonia. For this purpose, the air 21 is conducted via a cooling device 31 and a flow measurement 32 into a regeneration column 30. In the regeneration column, filling bodies 33 are likewise arranged to increase the surface area. The cleaning of the air 21 is carried out in the present example by acid washing in sulfuric acid 34. However, a wash with water or other acids is also possible. The air 21 flows through the regeneration onskolonne 30 from bottom to top, the sulfuric acid 34 is introduced according to the determined in the flow measurement 32 air flow in Gegen¬ stream in the regeneration column 30. By the mass transfer, an ammonium sulfate solution 35 forms. The cooling of the air facilitates the formation of the ammonium salt. The ammonium sulfate solution 35 is circulated out of the process via a siphon 36 for the pressure seal and reused as fertilizer.

The air 21, 23 is recycled during the stripping and subsequent regeneration. In the case of ventilation with fresh air, the CO 2 proportion contained in the air would have considerable disadvantages in terms of stripping. By the circular running guide, the ammonia contained in the air 21, 23 can be completely recovered wie¬, an ammonia discharge into the atmosphere is prevented verhin¬. By means of a heater 31 and a cooling device 24, the air 21, 23 is set to an optimum temperature for the respective process. With the method according to the invention and a corresponding device, it is possible to almost completely recover the nutrients phosphorus and nitrogen from urine. Both phosphorus and nitrogen fertilizers can be obtained directly from the process. A complex elimination of phosphorus and nitrogen in particular with high energy consumption is no longer necessary in the subsequent wastewater treatment. Nutrient accumulation in waters and their harmful effects are prevented.

The present invention is not limited to the described embodiments. Variations within the scope of the claims also fall under the invention.

Φ

Claims

Patent claims

1. Process for Separating Magnesium Ammonium Phosphate MAP

(16) from wastewater with addition of a precipitant (5) in a container (2), characterized in that the wastewater is essentially undiluted urine separated from faeces and other solids, the urine with the precipitant ( 5) is mixed and a resulting precipitate (9) and a depleted yellow water (8) are separated from each other discontinuously after a process time has elapsed.

2. Method according to the preceding claim, characterized. that the urine is obtained from a Separationstoilette and / or a urinal.

3. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the urine is adjusted to a pH of about 9 before mixing with the precipitating agent (5).

4. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the urine and the precipitating agent (5) are stirred for mixing.

5. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the separation of precipitated product (9) and abgere chertem yellow water (8) after a process time of at least 10 minutes.

6. Method according to one of the preceding claims, characterized qekenn- characterized in that the precipitated product (9) several times to separate re-added urine and / or precipitant (5) in the Behäl¬ ter (2) remains and thus larger particles of the precipitated product ( 9) are bred.

7. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the precipitate (9) is dewatered after the last separation of fused yellow water (8) and / or dried.

8. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the separated from the precipitation product (9) abgegerei- tured yellow water (8) in a storage container (13) is passed.

9. The method according to any one of the preceding claims, characterized oekenn- characterized in that in the storage container (13) collected abgeger- tured yellow water is heated in particular to about 5O ⁰ C.

10. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that in the storage tank (13) collected abgegerei- tured yellow water is heated for about 2 hours.

11.Verfahren according to any one of the preceding claims, characterized gekenn¬ characterized in that the depleted yellow water is promoted after heating in a stripping column (20).

12. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the depleted yellow water trickles in the stripping column (20) in the counterflow for the discharge of ammonia via filler (22).

13. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the depleted yellow water from the bottom of the stripping column (20) to a further treatment and / or the Vorla¬ container (13) is supplied.

14. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the air be¬ heated before entering the stripping column (20) and / or after leaving the stripping column (20) cooled. becomes.

15. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the from the stripping column (20) exiting air-ammonia mixture in a further column (30) is chemically gewa¬ rule.

16. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the air-ammonia mixture with water or acid, in particular sulfuric acid (34), nitric acid or phosphoric acid is washed.

17. A device for separating magnesium ammonium phosphate MAP (16) from wastewater with the addition of a precipitant (5) in a container (2), characterized in that the container (2) ei¬ ne supply (1, 4) for substantially undiluted and urine and a precipitant (5) separated from faeces and other solids, and the container (2) further comprises a drain line (12, 12). 19) for a precipitation product (9) and / or for depleted Gelbwas¬ water (8).

18. Device according to one of the preceding claims, characterized in that the undiluted urine is obtained from a separation toilet.

19. Device according to one of the preceding claims, characterized gekenn¬ characterized in that the container (2) is assigned a mixing device (7) for mixing see urine and precipitant (5).

20. Device according to one of the preceding claims, characterized gekenn¬ characterized in that the discharge line (12) for the precipitation product (9) is associated with a drying device (15).

21. Device according to one of the preceding claims, characterized gekenn¬ characterized in that the drying device (15) has a filter bag auf¬.

22. Device according to one of the preceding claims, characterized gekenn¬ characterized in that the outflow line (s) (12, 19) for the precipitation product (9) and / or for the depleted yellow water (8) in a Vorlage¬ container (13) opens ,

23. Device according to one of the preceding claims, characterized gekenn¬ characterized in that the supply container (13) is associated with a heater.

24. Device according to one of the preceding claims, characterized gekenn¬ characterized in that the feed tank (13) by means of a line (28) is connected to a stripping column (20).

25. Device according to one of the preceding claims, characterized gekenn¬ characterized in that in the stripping column (20) packing bodies (22) are arranged, via which the depleted yellow water (14) trickles from the top to the bottom th.

26. Device according to one of the preceding claims, characterized gekenn¬ characterized in that the stripping column (20) from bottom to top with air (23) can be flowed through.

27. Device according to one of the preceding claims, characterized gekenn¬ characterized in that at the bottom of the stripping column (20) a line to a further treatment device and / or the storage container (13) is arranged.

28. Device according to one of the preceding claims, characterized gekenn¬ characterized in that for the air (23) before entering the stripping column (20) a heater (24) and / or after leaving the Strippko¬ lonne (20) a Cooling (31) is arranged.

29. Device according to one of the preceding claims, characterized gekenn¬ characterized in that the stripping column (20) for the from the stripping column (20) exiting air-ammonia mixture with another column (30) is connected to the chemical washing.