CH616395A5 - Process for treating wet sludge from a sewage treatment plant and device for carrying out the process - Google Patents

Description

The invention relates to a process for the continuous treatment of wet sludge from a sewage treatment plant and to a device for carrying out the process.

It is known to expose sludge from sewage treatment plants in ig gas-tight mixing containers under pressure to wet composting. This method requires a device which is relatively complicated and expensive to construct, operate and maintain. The pressurized containers of this device also prove to be very dangerous in operation. In addition, the energy required for wet composting is extremely high in this device and very large containers are required, since very long ventilation times are required.

The purpose of the present invention is to provide a process which does not have the disadvantages mentioned above, i.e. with which it is possible to achieve a pasteurized sludge in a shorter time and with significantly less energy and investment expenditure than with all previously known processes.

3o The method according to the invention is characterized in that the wet sludge with a dry substance content of 3 to 25% is heated with the aid of a heat exchanger unit by at least 10 ° C to at least 25 ° C, then the wet sludge heated in this way is dewatered and 35 with a dry substance content of 10 to 28% in such an amount leads into a heat-insulated wet sludge aeration tank and in the same ventilates the sludge with an oxygen-containing gas or pure oxygen in such a way that temperatures of 64 to 72 ° C are reached in the sludge with the help of the heat generated during the biological, 40 thermophilic conversion process and that the warm sludge pasteurized in the wet sludge aeration tank is then allowed to flow through the heat exchanger unit to the freshly supplied wet sludge flowing through the heat exchanger unit without direct contact with the latter.

It is expedient if the sludge is dewatered to a dry matter content of 15 to 28% before it is introduced into the wet sludge aeration tank, preferably before flowing through the heat exchanger unit.

For various purposes, it is advantageous if the heated, pasteurized wet sludge 55, which has been removed from the wet sludge aeration tank and then passed through the heat exchanger unit, is preferably still warm after its exit from the latter, preferably at a temperature of at least 35 ° C. to a dry matter content of dewatered at least 35%, preferably to a dry matter content in the range of 40 to 55%. It is expedient if the wet sludge is dewatered to a dry matter content of at least 15%, preferably from 18 to 25%, using a dewatering device before it is introduced into the wet sludge aeration tank and the sludge thus dewatered in the wet sludge aeration tank is exposed to the biological conversion process. then the supply of fresh wet sludge to the drainage device is interrupted and the same drainage device on its entry side for further drainage of the wet

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slurry aeration tank located pasteurized slurry connects to the outlet side of the latter, and these dewatering steps are repeated alternately.

In order to achieve final rotting and to maintain the very desirable soil bacteria, it is advantageous if the pasteurized sludge, which has been dewatered to at least 35% dry matter content, is subjected to composting.

It is known to mix cold wet sludge with garbage or another dry substance, and then to aerate it in a treatment chamber, also called aeration reactor, for its composting, heat being generated by the biological conversion process taking place, and after a sufficiently long aeration time in the aeration reactor Humus arises. However, the processes known for this have the disadvantage that the very wet material to be ventilated, which is in the cold state, requires very long aeration times in the aeration reactor and thus a high energy expenditure for the aeration and a large-volume aeration reactor.

It has now been shown that the disadvantages of the above-mentioned method can be avoided

if the pre-composted, dewatered, pasteurized and still warm sludge in the wet sludge aeration tank is mixed with oxygen-containing gas or pure oxygen for its post-composting in a downstream aeration reactor until temperatures of 65 to 85 ° C in the aeration reactor are reached and humus through the biological conversion process with a dry matter content of 45 to 60%, preferably from 50 to 55%.

By pretreating the freshly obtained wet sludge in the wet sludge aeration tank at a temperature in the range from 64 to 72 ° C, the biological conversion process of the sludge in this tank takes place by means of thermophilic bacteria. The advantage of thermophilic digestion in the wet sludge aeration tank is that it takes place much faster than the processes previously carried out at much lower temperatures without thermophilic bacteria and the residence time of the material to be aerated, which is still required in the subsequent aeration reactor, in some cases up to around 50% of that at the very long residence time required so far can be reduced, so that the constructionally relatively complex aeration reactor can be dimensioned much smaller than before, and the residence time of the material to be treated in the entire treatment plant required is significantly shortened, since in all sludge treatment plants the Aeration reactor required for aeration of the dewatered sludge takes up most of the residence time required in the entire treatment plant. This also has the consequence that the total effort required for aeration of the material to be processed can also be greatly reduced when using the method according to the invention compared to the methods previously used.

In a subsequent composting in an aeration reactor, it is often expedient to add up to 20% dry waste and / or additives to the pasteurized sludge after it has been dewatered after the heat exchanger unit and before composting using a mixer.

The present invention furthermore relates to a device for carrying out the method according to the invention, which is characterized in that it has a heat exchanger unit for heating the freshly obtained wet sludge by at least 10 ° C. to a temperature of at least 25 ° C. and a unit connected to the heat exchanger unit Aeration-provided, heat-insulated wet sludge aeration tank for receiving and aeration of the wet sludge accruing from the heat exchanger unit, and that the outlet side of the wet sludge aeration tank is connected to the heat exchanger 5 unit, whereby the aerated, heated and pasteurized wet sludge transfers heat to the fresh wet sludge without direct contact.

In order to avoid that wet sludge freshly introduced into the wet sludge aeration tank relatively lowers the temperature of the total wet sludge contained in it, it is expedient if the wet sludge aeration tank has at least one perforated bottom 15 running perpendicular to its main flow direction and dividing it into at least two successive ventilation chambers . In order to avoid a vertical ascent of the oxygen-containing gas, e.g. Bubbles containing air or pure oxygen are advantageous if at least one liquid circulation device is assigned to each of the ventilation chambers, the latter being arranged and / or designed in such a way that the liquid in the individual ventilation chambers has a central axis running perpendicular to the perforated floor ongoing swirl is given. Furthermore, it is expedient for 2S if the wet sludge aeration tank has a cylindrical shape, at least one clearing arm is assigned to the bottom of the tank and each of the perforated floors, and the clearing arms are connected to one another and to a drive motor via a common drive shaft. It is advantageous if the heat exchanger unit has at least two containers, one of which is connected to the fresh sludge supply on its inlet side and to the wet sludge aeration container on its outlet side, and the other container is connected to the wet sludge aeration container on its inlet side, and in both Containers at least one heat exchange element through which a heat exchange liquid flows are arranged, which are connected to one another for the circulation of the heat exchange liquid via a line system. It is expedient 40 if the containers of the heat exchanger unit have a cylindrical inner cross section and the heat exchanger elements arranged concentrically to the longitudinal axes of the containers have a circular cross section, that in the interior of the heat exchanger elements and 45 between the outside thereof and the inside of these containers each have a wall scraper arrangement which is designed at the same time, are arranged parallel to the longitudinal axis of the liquid conveying device, the conveying directions of two concentric liquid conveying devices arranged in the same container opposite each other, such that during operation there is an at least approximately toroidal circulation flow around the heat exchanger elements, and that each of the containers with a 55 scraper movable over its floor.

The method of the invention is explained below with reference to the drawing for a device for carrying out the method, for example. Show it:

1 schematically shows an embodiment of a device according to the invention in elevation; and

Fig. 2 in plan the device shown in Fig. 1, with the heat exchanger unit and the wet sludge aeration tank in section.

In the device shown in the drawing, 65 of e.g. from a sewage treatment plant or a digestion wet sludge with a dry matter content of 3 to 8% via a finely ground shredder 1 by means of a pump 2 to a dewatering device 3, in

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which the wet sludge is dewatered to a dry matter content of 18 to 25%. From the dewatering device 3, the heavily dewatered wet sludge passes via the slides 5 and 6 and the connecting line 7 into the upper container 8 of the heat exchanger unit 10 which is provided with very good thermal insulation 9. The heat exchanger unit 10, which is thermally insulated on the outside, has, as can be seen from FIG. 1 , two containers 8 and 11 arranged one above the other for reasons of space, the upper container 8 being connected on its inlet side 8a to the fresh sludge supply 7 and on its outlet side 8b to the inlet of the wet sludge ventilation container 13 provided on the outside with a highly heat-insulating thermal insulation 12. The lower container 11 is connected on its inlet side 1 la via a slide 14 to the outlet of the wet sludge aeration tank 13 and on the outlet side 11b via a slide 15 and a line 16 to the drainage device 3.

In both containers 8 and 11 of the heat exchange unit 10, a heat exchange element 17 or 18, through which a heat exchange liquid flows, is arranged, which are connected to one another for the circulation of the heat exchange liquid via a line system 19, 20 and 21. In the line system 19, 20 and 21 connecting the heat exchanger elements 17 and 18 to one another, a heat pump 22 is arranged for additional heating of the heat exchanger liquid, in particular for additional heating in the case of relatively cold wet sludge and when starting up the entire system, which preferably originates from the clarification Water extracts heat and releases it to the heat exchange fluid at a higher temperature level.

As can be seen from FIG. 2, the containers 8 and 11 connected to one another at the end face have a cylindrical inner cross section and the heat exchanger elements 17 and 18 arranged concentrically to the longitudinal axes 23 of the container in the interior of the containers 8 and 11 have an annular cross section, with the heat exchanger elements 17 inside and 18 and between the outside thereof and the inside of these containers 8 and 11 a liquid conveying device 24 or 25, which is simultaneously designed as a wall scraper arrangement and conveys parallel to the longitudinal axis 23 of the container, is arranged. The conveying directions of two liquid conveying devices 24 and 25 arranged concentrically to one another and in the same container 8 and 11 run opposite to each other, so that during operation of the system there is an at least approximately toroidal circulation flow around the heat exchanger elements 17 and 18 and which are distanced from the container bottom thus a good heat transfer between the wet sludge located in the two containers 8 and 11 and the heat exchange liquid results. Since the liquid feed wheels 24 and 25 also serve as wall wipers, deposits that degrade the heat transfer on the surfaces of the heat exchanger elements 17 and 18 and deposits that reduce the tank volume on the inside walls of the tank are avoided properly and in a simple manner. The inner conveyor and scraper wheels 24 are fastened directly to the common drive shaft 27 coupled to a drive motor 26. The outer conveyor and scraper wheels 25 are fixedly connected to the drive shaft 27 via a floor scraper 28 each. In many cases, it is expedient if both containers 8 and 11 are each provided with a ventilation arrangement 29 opening into the bottom region for supplying oxygen-containing gas, such as air, or pure oxygen in the wet sludge located in these containers 8 and 11.

In the upper container 8 of the heat exchange unit

10 flowing, already partially dewatered, and thus having a lower volume and a higher solid concentration, is heated in this container 8, for example, to a temperature of approximately 45 ° C. and then via the outlet 8b and the line 30 into the wet. Sludge aeration tank 13 delivered. In order to avoid that the supply of fresh sludge via the line 30 into the wet sludge aeration tank 13 causes the temperature of the entire wet sludge located in the latter to drop below the pasteurization temperature of about 70 ° C., the inside of the wet sludge aeration tank 13 can be seen from FIG. 1 , divided, for example, by two perforated bases 31 and 32 into three ventilation chambers 13a, 13b and 13c which are arranged one below the other and are in liquid exchange with one another. These perforated intermediate floors 31 and 32 prevent wet sludge flowing into the top of the wet sludge aeration tank 13 and located at a lower temperature level from reaching the bottom of the tank 13 in the shortest way. With the aid of the perforated intermediate floors 31 and 32, ventilation chambers 13a, 13b and 13c, which are relatively strongly separated from one another in terms of flow, are formed, which, however, are in relatively good fluid transfer with one another.

In each of the individual ventilation chambers 13a, 13b and 13c, two liquid conveying devices 33 are arranged, which in the wet sludge located in the individual ventilation chambers 13a, 13b and 13c generate a swirl rotating about the vertical longitudinal axis of the container, so that the intermediate floors 31 and 32 and the scraper 35 assigned to the container bottom 34 and the hollow longitudinal axes of the liquid conveying devices 33 in the individual ventilation chambers 13a, 13b and 13c conveyed wet sludge, gas bubbles consisting of oxygen-containing gas, such as air, or pure oxygen, are prevented from rising vertically and thus remain in contact with the wet sludge to be aerated for a very long time.

Due to the strong aeration of the wet sludge, a biological conversion process takes place in it, which results in heating of the wet sludge. Due to the division of the wet sludge aeration tank 13 into three successive aeration chambers 13a, 13b and 13c, the sludge in the uppermost aeration chamber 13a has an average temperature of about 53 ° C, in the middle aeration chamber 13b an average temperature of about 65 ° C and in the lowest aeration chamber an average temperature from about 70 ° C. In this way, thermophilic bacteria become active, which causes the biological conversion process to run much faster than in the previously used processes and forms a high concentration of enzymes, which is very important for the subsequent process sequence.

The air to be conveyed into the interior of the wet sludge aeration tank 13 is metered from the compressor 36 via line 37 and the individual air flow meter 38 to the individual air introduction points. By regulating the amount of air introduced into the individual ventilation chambers 13a, 13b and 13c, the heat generated by the biological conversion process can be regulated in such a way that it does not rise above 72 ° C, which is extremely important since the biological activity is adversely affected at higher temperatures .

In addition, an inner wall scraper 57 fastened to the drive shaft 55 is provided in the interior of each ventilation chamber 13a, 13b or 13c, in order to avoid deposits on the inside of the container wall.

In order to accelerate the start of the biological conversion process when starting up the plant,

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In order to raise the temperature in the last chamber 13c to the desired temperature level or to avoid, in the case of certain sludge compositions, that the temperature of the sludge rises above a temperature above which the microorganisms important for the biological conversion process die, the container wall is in the area of the lowest chamber 13c formed as a double wall, through which a cold or warm, gaseous or liquid medium can be passed as required.

The wet sludge pasteurized and hygienized in the wet sludge aeration tank 13 can now be drawn off at the lower end of the tank 13 if necessary and e.g. can be removed via the slide 14 and the exhaust line 39 (A) for a liquid discharge for the field.

Most, or usually the entire part of the sludge pretreated in this way in the wet sludge aeration tank 13 is passed from the latter in the warmest possible state, for example 68 ° C., via line 40 into the second tank 11 of the heat exchanger unit 10, where it is carried out with the help of the heat exchanger element 18 withdraws as much heat as possible and is transferred to the freshly supplied sludge in the first container 8 for heating it.

After the supply of fresh sludge to the dewatering device 3 has been interrupted, the cooled, pasteurized and already partially dewatered sludge flowing out of the lower container 11 is again fed to the dewatering device 3 at a temperature of about 35 ° C. and therein to a dry substance content of 40 to 50% further drained. This alternating use of the dewatering device 3 makes very good use of it.

The pasteurized sludge, which is further dewatered in this way, can now be removed from the system via the slides 5 and 41 and the line B or fed to a dryer 47.

On the other hand, the pasteurized sludge, which is further dewatered in this way, can be fed via the slides 5 and 6 to a comminution and loosening apparatus 42, it being possible for additives to be added to the sludge before the latter by means of an admixing arrangement 43, waste also being used as additives.

The material emerging from the chopper and loosening apparatus 42 can now be fed via the slide 44 either to the conveying device 45 and thus to the aeration reactor 46 as well as to the outlet C or to the dryer 47 producing a dry granulate, the dry granulate conveying the system to the line E leaves.

As can also be seen from the diagram, the heat pump 22 heats air via a heat exchanger 48

is introduced into the dryer 47 via the line 49 in the warmest possible state.

If the heavily dewatered, pasteurized material is discharged via the conveying device 45 into the ventilation reactor 46, which is thermally insulated on the outside, then it is intensively aerated in a known manner with an oxygen-containing gas, such as air, with pure oxygen-enriched air or pure oxygen. In the hottest area of the ventilation reactor 46, temperatures in the range from 65 to 80 ° C. arise as a result of the biological conversion process.

After a sufficiently long dwell and aeration time in the aeration reactor 46, a healthy soil substance containing soil bacteria in humus-like form and with a dry matter content of about 50 to 55% can be discharged on the underside thereof.

By introducing pre-treated, heavily dewatered, pasteurized, warm sludge, the aeration reactor 46 can be dimensioned significantly smaller than before.

Depending on the type of material being treated, e.g. the aeration reactor 46 and / or the granulate-producing dryer 47 can be omitted.

It is also possible to use the hot exhaust gases drawn off from the ventilation reactor 46 via the line 50 for additional heating of the sludge in the container 8, the container 8 expediently being e.g. is formed with a double wall, between which the hot exhaust gases coming from the ventilation reactor 46 are passed.

In most cases, the top of the wet sludge aeration tank 13 is also provided with a foam breaker arrangement 51, an air suction line 52 and siphons and water separators 53 arranged in the latter. The water coming from the dewatering device 3 and the water separator 53 is fed back to the sewage treatment plant via line 54.

In order to avoid bacteriological contamination of the pasteurized sludge emerging from the wet sludge aeration tank 13 by the freshly fed sludge, it is expedient to replace the dewatering device 3 by two separate dewatering units, the one to be fed continuously to the upper tank 8 for cold cold dewatering Sludge and the second for continuous warm dewatering (at a temperature of about 25 to 40 ° C) of the pasteurized and hygienized sludge originating from the wet sludge aeration tank 13, and thus bacteriological contamination of the latter by the freshly fed sludge cannot take place .

Of course, the wet sludge aeration tank 13 and the heat exchanger unit 10 can also be arranged horizontally.

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2 sheets of drawings

Claims (29)

616395 1. A process for the continuous treatment of wet sludge from a sewage treatment plant, characterized in that the wet sludge with a dry substance content of 3 to 25% is heated by at least 10 ° C to at least 25 ° C with the aid of a heat exchanger unit, then the wet sludge heated in this way is dewatered and with a dry substance content of 10 to 28% in such an amount leads into a heat-insulated wet sludge aeration tank and in which the sludge is aerated with an oxygen-containing gas or pure oxygen in such a way that temperatures in the sludge with the help of the heat generated during the biological, thermophilic conversion process from 64 to 72 ° C, and that the warm sludge pasteurized in the wet sludge aeration tank for heat transfer to the freshly supplied wet sludge flowing through the heat exchanger unit flows through the heat exchanger unit without direct contact with the latter leaves. 2. The method according to claim 1, characterized in that the sludge is dewatered to a dry matter content of 15 to 28% before it is introduced into the wet sludge aeration tank, preferably before flowing through the heat exchanger unit. 2nd PATENT CLAIMS 3rd 616 395 has a perforated base (31, 32) running perpendicular to its main flow direction and subdivided into at least two successive ventilation chambers (13a, 13b, 13c). 3. The method according to claim 1 or 2, characterized in that the withdrawn from the wet sludge aeration tank and then passed through the heat exchanger unit heated, pasteurized wet sludge after its exit from the latter, preferably in a still state, preferably at a temperature of at least 35 ° C drained to a dry matter content of at least 35%, preferably to a dry matter content in the range of 40 to 55%. 4. The method according to claim 3, characterized in that the pasteurized sludge dewatered to at least 35% dry matter content is subjected to composting. 5 5. The method according to claim 4, characterized in that the dewatered sludge for its composting in a downstream aeration reactor with oxygen-containing gas or pure oxygen is passed through until the biological conversion process reaches temperatures of 65 to 85 ° C in the aeration reactor and humus with one Dry matter content of 45 to 60%, preferably from 50 to 55%, is formed. 6. The method according to claim 1, characterized in that for the continuous dewatering of the warm sludge located in the wet sludge aeration tank, a negative pressure is generated inside the wet sludge aeration tank and damp gas or moist gas and water vapor are drawn off from the latter. 7. The method according to any one of claims 1 to 6, characterized in that up to 20% dry waste and / or additives are added to the wet sludge. 8. Process according to claims 3 and 4, characterized in that up to 20% dry waste and / or additives are added to the pasteurized sludge after it has been dewatered after the heat exchanger unit and before composting by means of a mixer. 9. The method according to claim 8, characterized in that for further continuous dewatering of the sludge inside the mixer, a negative pressure is generated and damp gas or damp gas and water vapor are withdrawn from the mixer. 10th 10. The method according to claim 5, characterized in that the dewatered material is fed to the aeration reactor at a temperature of at least 35 ° C. 11. The method according to claims 5 and 8, characterized in that the emerging from the ventilation reactor, heated as a result of the heat generated by the biological conversion process, oxygen-depleted exhaust gas for heating the mixer and / or for additional heating of the freshly supplied wet sludge in the heat exchanger unit used. 12. The method according to claim 5, characterized in that the intensity of the aeration of the material located in the downstream aeration reactor and the discharge speed of the treated material are coordinated with one another in such a way that the latter has a dry matter content of 45 to 60%. 13. The method according to claims 2 and 3, characterized in that the wet sludge before it is introduced into the wet sludge aeration tank by means of a dewatering device to a dry matter content of at least 15%, preferably from 18 to 25%, and the sludge thus dewatered in the wet sludge aeration tank suspends the biological conversion process, thereupon interrupts the supply of fresh wet sludge to the dewatering device and connects the same dewatering device on its inlet side for further dewatering of the pasteurized sludge located in the wet sludge aeration tank to the outlet side of the latter, and repeats these dewatering steps alternately. 14. The method according to claims 3, 8 or 13, characterized in that the dewatered pasteurized sludge is fed to a drying device. 15 15. Device for carrying out the method according to claim 1, characterized in that it has a heat exchanger unit (10) for heating the freshly obtained wet sludge by at least 10 ° C to a temperature of at least 25 ° C and one connected to the heat exchanger unit (10), with ventilation means (36) provided, heat-insulated wet sludge aeration tank (13) for receiving and aeration of the wet sludge from the heat exchanger unit (10), and that the outlet side of the wet sludge aeration tank (13) is connected to the heat exchanger unit (10), whereby the ventilated , heated and pasteurized wet sludge transfers heat to the fresh wet sludge without direct contact. 16. Device according to claim 15, characterized in that it has a ventilation reactor which is intended for receiving the dewatered, pasteurized sludge and is connected downstream of the wet sludge aeration tank and which is provided with supply means for supplying oxygen-containing gas or pure oxygen. 17. The device according to claim 16, characterized in that a feed arrangement connected to a mixer is provided in order to add up to 20% dry waste and / or additives to the dewatered sludge before it enters the ventilation reactor. 18. Device according to claim 15, characterized in that a feed arrangement is provided in order to add up to 20% dry waste and / or additives to the warm sludge located in the wet sludge aeration tank. 19. Device according to claim 15 or 17, characterized in that the interior of the wet sludge aeration tank and / or the mixer with at least one negative pressure generator for generating negative pressure inside the same or the same and for extracting moist gas or moist gas and water vapor from the same or the same , connected is. 20th 20. Device according to claim 15, characterized in that the wet sludge aeration tank (13) at least 21. Device according to claim 20, characterized in that each of the ventilation chambers (13a, 13b, 13c) at least 'At least one liquid circulation device (33) is assigned, the latter being arranged and / or designed in such a way that the liquid in the individual ventilation chambers is given a DraE which runs around a chamber central axis running perpendicular to the perforated floor (31, 32). 22. Device according to claim 20 or 21, characterized in that the wet sludge aeration tank (13) has a cylindrical shape, the tank bottom (34) and each of the perforated floors (31, 32) is assigned at least one clearing arm (35, 35), and the clearing arms (35, 35) are connected to one another and to a drive motor (56) via a common drive shaft (55). 23. Device according to claim 15, characterized in that the heat exchanger unit (10) has at least two containers (8, 11), of which one container (8) on its inlet side (8a) with the fresh sludge supply (7) and on its outlet side (8b) with the wet sludge aeration tank (13), and the other tank (11) on its inlet side (IIa) is connected to the wet sludge aeration tank (13), and that in both tanks (8, 11) at least one heat exchange element through which a heat exchange liquid flows (17, 18) is arranged, which are connected to one another for the circulation of the heat exchange liquid via a line system (19, 20, 21). 24. The device according to claim 23, characterized in that a heat pump (22) is arranged in the line system (19, 20, 21) connecting the heat exchanger elements (17, 18) to one another for additional heating of the heat exchanger liquid, which preferably comes from the one from the secondary clarification Water removes heat. 25. The device according to claim 23, characterized in that the containers (8, 11) of the heat exchanger unit (10) have a cylindrical inner cross-section and the heat exchanger elements (17, 18) arranged concentrically to the longitudinal axes of the container have a circular cross-section that in the heat exchanger elements ( 17, 18) enclosed interior as well as between the outside of the same and the inside of these containers (8, 11) a liquid conveying device (24, 25), designed simultaneously as a wall scraper arrangement and parallel to the longitudinal axis of the container, is arranged, the conveying directions of two concentric to each other and Liquid conveying devices (24, 25) arranged in the same container run opposite to one another in such a way that, during operation, there is an at least approximately toroidal circulation flow around the heat exchanger elements (17, 18), and that each of the containers (8, 11) has one over its bottom movable en clearer (28) is provided. 25th 30th 35 40 45 50 55 60 65 26. Device according to claim 25, characterized in that the containers (8, 11) are connected to one another at the end faces to form a single unit, and a single drive shaft (27) connected to a drive motor (26) for all liquid conveying devices (24, 25) and reamer (28) is provided. 27. The device according to claim 23, characterized in that in both containers (8, 11) ventilation means for supplying oxygen-containing gas or pure oxygen in the sludge located in these containers are provided. 28. Device according to claim 26, characterized in that the outer liquid delivery device (25) is fixedly connected to the scraper (28). 29. The device according to claim 20, characterized in that each of the ventilation chambers (13a, 13b, 13) is provided with at least one inner wall wiper (57).