CH648011A5 - Arrangement for composting organic waste materials and sewage sludge, and process for the operation of this arrangement - Google Patents

Abstract

The material to be composted, which is in processed form, is fed at a uniform rate into a container (11), which is completely closed, by means of a feed device (19). Each particle with which the arrangement is charged migrates through this container (11) within a column of material (HW) in the course of 14 to 20 days, whereupon it is discharged in the form of compost at the bottom by means of a discharge worm (16). The air required for the composting process is passed from the bottom in countercurrent relative to the column of material, using a forced draught fan and an exhaust fan (33), a filter (31) being arranged downstream of the exhaust fan (33). This allows optimal composting of the material. <IMAGE>

Description

** WARNING ** beginning of DESC field could overlap end of CLMS **.

PATENT CLAIMS 1. Arrangement for composting organic waste and sewage sludge, consisting of an upright container of circular cross-section, which a feed device for the compost material, a discharge device for the compost produced during the stay in the container and a ventilation device for controlled ventilation of the container as a column of material Compost goods migrating downwards are characterized by the following features: a) the container (11) is hermetically sealed; b) the feed device contains a mixing device with a screw conveyor (FS) for generating the composting the material from 10 to 15 percent by volume of sawdust, 20 to 30% by volume of composted compost and 55 to 70 volume percent garbage and mud; c) the feed device is followed by a circular disk (6, 7, 8) of different diameters, the centrifugal disc (1), the speed of which is adjustable, for Purposes that over the discharge edges of the individual circular washers the conspicuous bulk material particles of the goods a level filling the container (11) effecting Throwing parabolas are forced; d) the ventilation device is arranged on the sole (13) of the container (11) and has in radial, mutually ver arranged tubes (BR1 -BR4) ventilation openings (21), the one of which is fed by a blower (28) Supply line (23) fed supply lines (Stl-St4) can be opened or closed via controllable switching valves (SV1SV4), and is provided with an exhaust air line (30) pointing to a suction fan (33); e) serves as a discharge device, a discharge screw (16), which is supported by a pivoting cylinder (15) projecting into the container (11), the discharge screw (16) and the pivot cylinder (15) each having a hydraulic drive motor (Ji or M2) is assigned, which are hydraulically connected in series.

2. Arrangement according to claim 1, characterized in that the ventilation openings (11) are grouped together and divided into sectors (ad) and arranged one after the other via time switches ZS1-ZS4) to the common supply line (23), and that the opening times of the switching valves (SVI-SV4) overlap each other.

3. Arrangement according to claims 1 and 2, characterized in that means (38) are provided which control the amount of air flowing through the container from bottom to top by means of the pressure and suction blower (28 and 33) in such a way that the CO2 content of the exhaust air leaving the container (11) is between 2 to 5%, and the temperature of the introduced air can be regulated to +30 to +50 "C.

4. Arrangement according to claims 1 to 3, characterized in that the hydraulic drive motors (mol, M2) each have the same absorption volume and are each connected via a mechanical reduction gear to the discharge screw (16) and the swivel cylinder (15).

5. Arrangement according to claims 1 to 4, characterized in that the suction device (33) is followed by a filter device (34).

6. Arrangement according to claims 1 to 5, characterized in that the supply line (23) is connected to a moistening device.

7. The method for operating the arrangement according to claim 1, characterized in that the amount of air flowing through the container from the bottom up is controlled by means of the pressure and suction blower in such a way that the CO2 content of the exhaust air leaving the container is between 2 to 5 Where is it and that the air is introduced into the material column at a temperature of + 30 to + 500C.

The invention relates to an arrangement for composting compost material from organic waste and sewage sludge, consisting of an upright container of circular cross-section, a feed device for the compost material, a discharge device for the compost produced during the stay in the container and a ventilation device for controlled ventilation of the compost material that passes through the container as a column of material from top to bottom.

Such an arrangement is known for example from DE-AS 2 253 009. With exact observance of the parameters influencing the rotting process, which are essentially controlled by the air supply, a different heat and oxygen stratification as well as a different distribution of specific bacteria should be achieved within the material column in the ventilation reactor, which leads to differentiated aerobic and anaerobic bacterial activity that is optimal for the rotting process leads.

In order to obtain a hygienically perfect, biologically active, valuable humus material as the end product, however, precise control of the rotting process is necessary, otherwise there is neither an optimization, for example as regards the duration of the process and the quality of the end product, nor can it be maintained.

Since, in the known method, the material to be rotten is aerated by means of a single pressure blower as it passes through an aeration reactor open at the top, a number of difficulties arise. The material column must be ventilated against atmospheric pressure so that it is difficult to reliably guide the pressure in the material column.

Excessive air supply dries out the material column in the ventilation reactor so that bacterial activity comes to a standstill. If the air supply is too low, the number of anaerobes increases significantly. Since the air enriched with particles, suspended matter and odorous substances leaves the ventilation reactor after flowing through the material column, it gets into the atmosphere, which can lead to environmental pollution. Furthermore, atmospheric precipitation reaches the material column and changes the moisture in the material column in an uncontrollable manner. In order to return the moisture content to normal values, heated air and / or dry carbon carriers must be supplied to the material column in excess. Due to the low speed with which the material column travels through the ventilation reactor, it takes a relatively long time for the normal moisture conditions to be restored. An incorrect air supply also causes condensation in the material column, which is detrimental to the rotting process. In the cold season, cold falling into the open ventilation reactor also leads to undesirable condensation. Furthermore, the rotting process is disturbed in the event of irregular discharge, since this also partially dries out on the sole of the material column from where it is discharged. As experience has shown, this also leads to changes in the biological balance in the material column. In addition to unpleasant odors, the rotting process can also come to a complete standstill.

Each partial drying out of the material column also leads to irregularities in the heat flow and favors further drying out, as is well known, dry material is a poorer heat conductor than moist material. The bacterial activity only comes to a partial standstill, then stops altogether and the material column sticks to the aeration reactor, which leads to considerable difficulties during discharge.

The exhaust air escaping from the ventilation reactor open at the top then contains a disproportionate number of unpleasant odorous substances.

The air supply into the container, which determines the course of the biological rotting process, is therefore also dependent on the moisture content of the waste, in particular the moisture content of the material column in the ventilation reactor. It must therefore also be taken into account when regulating the air supply and the associated supply of oxygen to the bacteria - in order to prevent irregularities in the course of the rotting process, in particular to prevent the anaerobic bacterial strains from growing disproportionately and to prevent the bacterial activity from being interrupted as a whole.

If the air is supplied to the column of material evenly distributed over the cross-section from below in order to aerate it in counterflow - i.e. in the opposite direction to the slow movement of the column of material - it has been shown that despite the uniform air supply over the entire cross-section of those in the container Material column, the discharged compost has different moisture and different degrees of rotting. If, when an empirically found permissible moisture level of the discharged compost material is exceeded, the air throughput is increased until the discharged compost material shows the desired moisture, as experience shows, this leads to drying zones within the material column, which is also undesirable, because then at this point the rotting process stops.

Finally, since these are quasi-continuous processes, the uniform feeding and removal of compost material is crucial for the rotting process.

So that the rotting conditions within the material column are always the same, it is necessary that the desired partial pressure remains somewhat constant in the individual heights of the pile (the material column) in order to always provide the pressure blower with the same pre-pressure. The compost to be refilled must therefore be refilled as evenly as possible from above and removed from the base of the material column.

Finally, before the compost is filled into the container, it must be processed so that it has a rotable composition, i.e. a rotable C / N ratio, and the air resistance for the pressure blower is as constant as possible.

The invention has for its object to provide a new arrangement for rotting or composting organic waste and / or sewage sludge, which enables the apparatus to meet the requirements mentioned above, so that the waste within the material column when passing through the container are ventilated in such a way that an optimal differentiated rotting can take place, i.e. aerobes and anaerobes as well as microorganisms like all types of actinomycetes that find comfortable living conditions in different biological layers within the material column, which layers have different temperature and oxygen ratios.

This object is achieved according to the invention by the following features, some of which are known per se: a) the container is sealed airtight; b) the feed device contains a mixing device with a screw conveyor for generating the compostable material from 10 to 15 percent by volume of sawdust, 20 to 30% by volume of composted compost and 55 to 70 percent by volume of organic waste such as municipal Sewage sludge or garbage; c) the feed device is followed by an existing of circular disks of different diameters Centrifugal disc, the speed of which is adjustable, for the purpose that the discarding bulk particles of the compost are good, causing a level filling of the container over the discharge edges of the individual circular rings Throwing parabolas are forced; d) the ventilation device is arranged on the bottom of the container and has in radial, staggered tubes arranged ventilation openings, which are fed with a supply line fed by a blower Supply lines can be opened or closed via controllable switching valves, and is equipped with an exhaust line with a suction fan; e) serves as a discharge device, a discharge screw, which is carried by a projecting into the container swivel cylinder conditions, the discharge screw and the Schwenkzylin each of which is assigned a hydraulic drive motor, which are hydraulically connected in series.

Particular embodiments of the invention result from the dependent claims.

With the aid of the arrangement according to the invention, the air flowing through the container is simultaneously blown and sucked and the container is closed on all sides, so that a negative pressure can be generated above the reactor contents. Accordingly, both the amount of oxygen passed through and the pressure difference between the bottom and the top of the container, and hence the partial pressure of the oxygen in the different layers of the material column, can be adjusted. In combination with the countercurrent process used, this ensures perfect ventilation of the entire container contents and allows the partial pressure to be adapted to the living conditions of the different types of microorganisms involved in the rotting process. Another advantage is that the material column in the container despite the air flowing from the bottom upwards, which is extremely important for the hygiene, if necessary moisture can be supplied, so that a partial or complete drying out of the material column can be prevented with certainty. In addition, it is possible to regulate the flow rate of the air flowing through the container even if the other parameters mentioned above are observed, which can influence and optimize the temperature stratification in the material column Both blowers and the supply of moisture influence the biology in the material column in such a way that the rotting process runs optimally over any period of time, regardless of the ability of operating personnel, i.e. without manual intervention.

The air can preferably be introduced in sectors and, after passing through a certain layer of material, can be distributed over this sector over the entire material column, so that with the aid of the ventilation device, partial wetting of the material column passing through the container can be eliminated in a simple manner by partially different ventilation in that the Wet zones on the base of the material column determined at the discharge can be ventilated more than other zones on the base of the material column. A so-called forced ventilation can thus be achieved, through which the material column to be rotten is partially or more strongly aerated in its cross-section and thus the water content of the compost material to be discharged can be regulated in relation to the respective sector. It is therefore ensured that the desired influencing only takes place within the sector concerned. The opening times of the switching valves can overlap, which can ensure that there is always an air flow through the material column. Another advantage of the ventilation device can be seen in the fact that the maximum available ventilation capacity can be used in the short term to ventilate only one sector, in order to eliminate short-term compression and waterlogging of the material column. The feed device and the discharge device are operated in such a way that each particle of the compost material introduced within the material column in the container travels through the container in about 14 to 20 days.

The invention is described below with reference to an embodiment shown in the drawing. Show it: 1 is a schematic representation of the arrangement according to the invention, 2 is an enlarged view of the compost material feed device, 3 is an enlarged view of the discharge device of the arrangement according to FIG. 1, Fig. 4 is a section along the line IV-IV in Fig. 3 and Fig. 5 is a hydraulic circuit diagram of the drive motors.

On a foundation 10 found in the ground (cf.

3), a container 11, which is circular in cross section, is arranged upright, the wall of which is thermally insulated and has a central inlet opening 4 at the top and (FIG. 2) a likewise central opening 14 on the sole 13. Through this opening, the swivel cylinder 15 of a discharge screw 16 protrudes via a motor M2 shown in FIG. 5 and via a gear (not shown). The discharge screw 16 is arranged near the base 13 of the container and is also via a gear and shown in FIG a motor M1 driven.

Above the discharge screw 16, when the container 11 is filled, there is a material column HW (see FIG. 1), which consists in its top layer of non-rotten garbage and mud and in its bottom layer it consists of rotten material, which is removed by the rotating discharge screw and is discharged centrally via an outlet nozzle 18. A loading device 19 is provided at the upper end of the container for the entry of the waste to be rotten. The column of material consisting of waste of different degrees of rotting thus slowly traverses the container 11 from top to bottom.

As shown in FIGS. 3 and 4, four ventilation openings 21 with ventilation pipes BRI to BR4 are arranged near the base 13 of the container 11, each at a distance of 900 from one another, each via a riser Stl to St4, each of which has an electromotive actuated control valve SVI to SV4, are connected to a ring line 23. The ring line is fed by a pressure blower 28 with compressed air via a supply line 25, in which a control valve 26 adjustable by a motor is provided.

Furthermore, four partitions 29 are provided on the bottom of the container 11, which protrude above the ventilation pipes. Through this arrangement, individual sectors a to d filled with gravel K are formed for the ventilation of the material column HW, which are each supplied with fresh air by one of the ventilation pipes and over which the discharge screw 16 extends.

A humidification device, not shown here, can be connected to the supply line 25.

The air-gas mixture emerging from the surface of the material column in the container is sucked off via a suction line 30, which opens into the cover 31 of the housing 11 and leads to a suction blower 33, and blown into the atmosphere via a schematically illustrated filter 34. Furthermore, the CO2 content in the exhaust air is determined via a separate measuring line ML.

The operation of the device described will now be described with reference to FIG. 1.

The fresh air sucked in by the pressure blower 28 is conveyed into the container 11 via the control valve 26, the ring line 23, the risers Stl to St4 and the ventilation pipes BR1 to BR4 (FIGS. 3 and 4) in order to flow through the material column HW there. A negative pressure is generated above the material column by means of the suction pump 33, so that the air / gas mixture emerging at the upper end of the material column is suctioned off and transferred to the atmosphere in a cleaned manner via a filter 34.

Depending on, for example, the CO2 content in the exhaust air and a predetermined target value, the air throughput through the material column is controlled in a predetermined manner via a controller 38, which influences the motor adjusting the control valve 26. The regulation is based on a CO2 content of 2 to 5%, preferably 3.5 u / 0.

As a result of the above-mentioned control valves ST1 to St4, which are transferred one after the other from the closed to the open position and after a predetermined time back to the closed position via time switches ZS1 to ZS4, the material column is vented in sectors, e.g. in the order: Sector a - Sector b - Sector c Sector d - Sector a etc. in the same time periods based on empirically found periods. In this case, the air quantity blown into the material column on the basis of the predetermined setpoint value and the measured actual values is conveyed via the controller 38. The air blown into the respective sector is distributed over this sector over the entire cross section of the container from above after passing through a certain material layer material column slowly migrating below and flows through it in counterflow in order to be suctioned off after flowing through in the manner already mentioned.

In the simplest case, the setting of the time switches ZS, that is to say a change in the predetermined ventilation time of the individual sectors, is adjusted manually due to the moisture content of the material just discharged from the discharge screw 16. A mechanical display (not shown) shows in which of the sectors a to d the discharge screw is currently located, in Fig. 2 e.g. especially in sector B. To influence the moisture of the material just discharged, the setting of the timer ZS2 must be changed in this case. As soon as the moisture in this section of the material column is correct, the adjustment is reversed. Of course, the time switches can also be set via a controller influenced by a moisture meter arranged in the discharge 18.

As shown in FIG. 2, the feed device 19 consists of a trough conveyor device TF, which is releasably connected to the container 11 on a cover plate 3 by means of a flange 2.

In a cylindrical opening 4 there is an arrangement A for filling the container 11 at the same level, which comprises a drive motor M, an associated gear G, the horizontal trough conveyor TF already mentioned, a vertically arranged screw conveyor FS and a centrifugal disc ST.

The centrifugal disc consists of several horizontally arranged annular disks 6, 7 and 8, which have different diameters D and different width B and are rigidly fixed to a rotatably mounted vertical shaft 10 at fixed height intervals H. For example, the outer diameter of the smallest circular disk 6 is approximately

two hundred, the middle circular disk 7 approximately four hundred and the largest circular disk 8 approximately six hundred millimeters, while their mutual distance H is approximately 100 mm.

The lowest annular disk 6 is welded to a hub 41 which is fixedly connected to the shaft 10 (FIG. 2). The further annular disks 7 and 8 are rigidly connected to one another and to the annular disk 6 by welded-on spacer pieces 42, the arrangement being such that the spacers do not cause any imbalances and the annular disk with the largest diameter faces the screw conveyor FS. Radial blades 43 are connected to the surface of the said circular disk 8 in order to be able to better drop material falling on its surface.

On the shaft 10, the vertically arranged screw conveyor FS is also attached, which projects into the trough space 45 of the trough conveyor TF, which is coated with bulk material via an opening 46.

Between the screw conveyor FS and the upper circular disk 8 there is a metering disk 47 having radial slots 48.

The trough conveyor TF also has a screw conveyor 52 which is rotatably mounted in side parts 49 and 50 of the housing 51 and is driven by a V-belt wheel 53. Instead of a screw conveyor, a conveyor chain can of course also be used. The shaft 10 is rotatably mounted in the housing 51 by means of a bearing 54 and at 55 by means of a foot bearing and is driven by the motor M via a V-belt 57 and the transmission G. The trough conveyor TF preferably has its own drive, which is not shown here.

The operation of the feed device described is as follows: The bulk material fed in at 46, in the form of material to be composted, for example comminuted waste with a grain size of up to 5 cm, or sewage sludge, for example in pelletized form, is brought to the screw conveyor FS by the trough conveyor TF and is ejected by the latter through the slots 48. A mixture of 10 to 15 percent by volume of sawdust, 20 to 30 percent by volume of composted material and 55 to 70 percent by volume of organic waste such as municipal sewage sludge or waste is preferably added. The ejected material falls on the individual annular disks 6 to 8 of the centrifugal disc set in rotation by the motor M and reaches the outside by the centrifugal force, from where it is dropped into the container 11 via the discharge edges.

As a result of the different widths of the individual annular disks, the annular disk 8 is allocated a larger amount of material than the annular disks 7 and 6 connected downstream of it. The speed of the shaft 10, the diameters D and widths B of the individual annular disks and their height spacings H are now chosen such that under Taking into account a predetermined discharge height, the individual bulk particles leaving the discharge edges are forced onto throwing parabolas dependent on gravity and centrifugal force, so that they are deposited in approximately the same layer thickness on the surface of the material column already in the container. In this way, a level, i.e. level, filling of the container takes place. A material column located in the container can thus be kept at the same height by continuous dispensing of material with constant discharge at the bottom thereof, the filled surface of the material column always being approximately flat is held without additional distribution organs having to be provided for this.

Such a column of material thus offers approximately the same air resistance for the fan 28.

By changing the speed of the shaft 10 by means of the gear G mentioned, the discharge height at which a level filling with bulk material takes place can be changed so that the container 11 can also be filled level from an empty state.

3 and 5, the discharge device consists of the discharge screw 16 already mentioned, which is rotatably mounted in the swivel cylinder 15. The drive of the discharge screw and swivel cylinder is shown in Fig. 5.

As the hydraulic circuit diagram shown there in a highly schematic manner, the pressure medium necessary for the operation of the hydraulic motor M1 driving the discharge screw and the hydraulic motor M2 driving the swivel cylinder is supplied with the aid of a control pump RP driven by a drive motor AM. The pressure medium is via a line 60 to a pressure accumulator SP and via a safety valve V1 and a line 61 to the hydraulic motor M2 for driving the swivel cylinder 15 and via a line 62, a rotary union DD - which is necessary as a result of the rotating swivel cylinder - and a line 63 the hydraulic motor M1 for driving the discharge screw 16 and via a line 64 the rotary feedthrough and a line 65 are returned to the control pump RP. A line 66 forms a bypass for the control pump leading to the oil sump OS. A further bypass is provided for the hydraulic motor M2, which is formed by a pressure-dependent switching valve SV and the line sections 67 and 67.

The high-speed hydraulic motors M1 and M2, which serve as drive motors for the discharge screw and the swivel cylinder and which generate the conveying and feed movements, have the same displacement volume, that is to say the same outputs, and, as shown in FIG. 5, are hydraulically connected in series.

The hydraulic motors M1 and M2 are therefore interchangeable. Through this series connection, the speeds of the discharge screw and swivel cylinder are coupled to one another, the transmission ratio being changeable via an adjustable eccentric (not shown), that is to say adaptable to different material to be discharged or to different sizes of rotting containers or silos. Due to the bypass, which can be switched on as a function of the pressure in front of the hydraulic motor M2, if there is any undesired compression of the material column in front of the discharge screw, the hydraulic motor M1 which generates the conveying movement continues to be operated alone in order to be able to discharge the material causing the compression the bypass connecting the oil sump OS - line 66 - only occurs when the hydraulic motor M1 can no longer flow through due to malfunctions of the pressure medium.

With a diameter of the rotting container 11 of approx. 6 m and a diameter of the discharge screw of approx. 250 mm, a degree of filling of the discharge screw of approx. 50%, which corresponds to a loosening of the material to be discharged of 1: 2, and a feed of approx. 5.52 mm per revolution of the discharge screw, the transmission ratio between the conveying and feed movement is approximately 1: 3590. The power requirement for the drive device is approximately 3 to 4 kW.

The invention also relates to an advantageous method for operating the described arrangement, according to which the amount of air flowing through the container from the bottom up is controlled by means of the pressure and suction fan such that the CO2 content of the exhaust air leaving the container is between 2 and 500 , and that the air is introduced into the material column at a temperature of approximately + 30 to + 50 "C.

Claims (7)

PATENT CLAIMS 1. Arrangement for composting organic waste and sewage sludge, consisting of an upright container of circular cross-section, which a feed device for the compost material, a discharge device for the compost produced during the stay in the container and a ventilation device for controlled ventilation of the container as a column of material Compost goods migrating downwards are characterized by the following features: a) the container (11) is hermetically sealed; b) the feed device contains a mixing device with a screw conveyor (FS) for generating the composting the material from 10 to 15 percent by volume of sawdust, 20 to 30% by volume of composted compost and 55 to 70 volume percent garbage and mud; c) the feed device is followed by a circular disk (6, 7, 8) of different diameters, the centrifugal disc (1), the speed of which is adjustable, for Purposes that over the discharge edges of the individual circular washers the conspicuous bulk material particles of the goods a level filling the container (11) effecting Throwing parabolas are forced; d) the ventilation device is arranged on the sole (13) of the container (11) and has in radial, mutually ver arranged tubes (BR1 -BR4) ventilation openings (21), the one of which is fed by a blower (28) Supply line (23) fed supply lines (Stl-St4) can be opened or closed via controllable switching valves (SV1SV4), and is provided with an exhaust air line (30) pointing to a suction fan (33); e) serves as a discharge device, a discharge screw (16), which is supported by a pivoting cylinder (15) projecting into the container (11), the discharge screw (16) and the pivot cylinder (15) each having a hydraulic drive motor (Ji or M2) is assigned, which are hydraulically connected in series. 2. Arrangement according to claim 1, characterized in that the ventilation openings (11) are grouped together and divided into sectors (ad) and arranged one after the other via time switches ZS1-ZS4) to the common supply line (23), and that the opening times of the switching valves (SVI-SV4) overlap each other. 3. Arrangement according to claims 1 and 2, characterized in that means (38) are provided which control the amount of air flowing through the container from bottom to top by means of the pressure and suction blower (28 and 33) in such a way that the CO2 content of the exhaust air leaving the container (11) is between 2 to 5%, and the temperature of the introduced air can be regulated to +30 to +50 "C. 4. Arrangement according to claims 1 to 3, characterized in that the hydraulic drive motors (mol, M2) each have the same absorption volume and are each connected via a mechanical reduction gear to the discharge screw (16) and the swivel cylinder (15). 5. Arrangement according to claims 1 to 4, characterized in that the suction device (33) is followed by a filter device (34). 6. Arrangement according to claims 1 to 5, characterized in that the supply line (23) is connected to a moistening device. 7. The method for operating the arrangement according to claim 1, characterized in that the amount of air flowing through the container from the bottom up is controlled by means of the pressure and suction blower in such a way that the CO2 content of the exhaust air leaving the container is between 2 to 5 Where is it and that the air is introduced into the material column at a temperature of + 30 to + 500C. The invention relates to an arrangement for composting compost material from organic waste and sewage sludge, consisting of an upright container of circular cross-section, a feed device for the compost material, a discharge device for the compost produced during the stay in the container and a ventilation device for controlled ventilation of the compost material that passes through the container as a column of material from top to bottom. Such an arrangement is known for example from DE-AS 2 253 009. With exact observance of the parameters influencing the rotting process, which are essentially controlled by the air supply, a different heat and oxygen stratification as well as a different distribution of specific bacteria should be achieved within the material column in the ventilation reactor, which leads to differentiated aerobic and anaerobic bacterial activity that is optimal for the rotting process leads. In order to obtain a hygienically perfect, biologically active, valuable humus material as the end product, however, precise control of the rotting process is necessary, otherwise there is neither an optimization, for example as regards the duration of the process and the quality of the end product, nor can it be maintained. Since, in the known method, the material to be rotten is aerated by means of a single pressure blower as it passes through an aeration reactor open at the top, a number of difficulties arise. The material column must be ventilated against atmospheric pressure so that it is difficult to reliably guide the pressure in the material column. Excessive air supply dries out the material column in the ventilation reactor so that bacterial activity comes to a standstill. If the air supply is too low, the number of anaerobes increases significantly. Since the air enriched with particles, suspended matter and odorous substances leaves the ventilation reactor after flowing through the material column, it gets into the atmosphere, which can lead to environmental pollution. Furthermore, atmospheric precipitation reaches the material column and changes the moisture in the material column in an uncontrollable manner. In order to return the moisture content to normal values, heated air and / or dry carbon carriers must be supplied to the material column in excess. Due to the low speed with which the material column travels through the ventilation reactor, it takes a relatively long time for the normal moisture conditions to be restored. An incorrect air supply also causes condensation in the material column, which is detrimental to the rotting process. In the cold season, cold falling into the open ventilation reactor also leads to undesirable condensation. Furthermore, the rotting process is disturbed in the event of irregular discharge, since this also partially dries out on the sole of the material column from where it is discharged. As experience has shown, this also leads to changes in the biological balance in the material column. In addition to unpleasant odors, the rotting process can also come to a complete standstill. Each partial drying out of the material column also leads to irregularities in the heat flow and favors further drying out, as is well known, dry material is a poorer heat conductor than moist material. The bacterial activity comes only partially, then stops altogether and it ** WARNING ** End of CLMS field could overlap beginning of DESC **.