Method for, in particular accelerated, aerobic microbiological decomposition of biological substances.

The invention relates to a method of, in particular accelerated, aerobic microbial degradation of organic substances, eg. As household waste with biological waste materials of a cover layer, eg. As soil, clay, foil, is covered.

The domestic but also industrial waste has increasingly a greater proportion of microbiologically degradable substances, u. Btw. Biological substances on. These substances are subject to short-term microbiological fermentation, so that not only in terms of hygiene must be worn for regular and short-term disposal bill. The usually collected by municipalities or associations waste can either be incinerated, in which case the subject flue gases of a treatment and the slag has to be stored, or disposed directly. In such landfills one hand ensure should be taken that there is no direct access is given to the groundwater. This can be achieved either by suitable geological siting or by providing their own interfaces. Furthermore, such landfills are usually sealed with a cover layer at the intended final height, which may for example consist of clay or earth. Normally, when the waste in such a landfill is subject to an anaerobic fermentation, is to be worn for the derivation of the gases on the one hand and on the other malodorous explosive concern. Therefor it is known that Gasableitsysteme A diversity constructed are provided in such a landfill, where the content of combustible gases may be so high that not only a flaring of the gases is carried out, but the gases for energy utilization are supplied. For example, gas engines can operate od. Like.

Is now a shift from landfill necessary, where a contamination of the environment, eg. As the groundwater to avoid, or even at the location of the landfill to supply a different purpose, it is necessary, the deposited substances to decontaminate odor while in a form on out that takes place at least in the deployment, z. B. to a new landfill, no unpleasant odor.

For this purpose it has been proposed that anaerobic fermentation, in which usually the odor is due to stop by freezing the substrates such. As the teilfermentierten household waste. Although such a method is able to function effectively, the disadvantage is that a very large amount of energy for cooling the substrates is required, and then the degradation of landfill comes an increased expenditure of energy used to the then rock-like material since the frozen water as a binder used to crush into transportable sizes.

It is also already a process has become known in which, optionally enriched by forcibly introducing air with oxygen originally present anaerobic fermentation is transferred to an aerobic fermentation. In a few days to weeks of fermentation is then ensured that during the dismantling of the landfill and the seduction of the substances no odor nuisance occurs because an aerobic fermentation is present. To accelerate the aerobic degradation of substrates in the landfill can, optionally with oxygen-enriched air are introduced into shock waves into the substrate, while simultaneously a suction of air is carried out together with the fermentation gases. Although such a method with regard to the odor nuisance, is quite successful, consists precisely in the initial phase of a slow start operation, with the risk that highly explosive methane / air mixtures for extended periods reach the outside.

The present invention has set itself the goal of creating a method that in addition to the reduction of odor nuisance, z. B. the degradation of landfill, also allows faults as are provided for example by explosive air / gas mixtures to avoid, , and allows a very rapid degradation and thus mineralization of biogenic substances.

The inventive method for, in particular accelerated, aerobic microbial degradation of organic substances, eg. As household waste with biological waste materials, which are covered by a cover layer, eg. As soil, clay, foil and optionally against the ground with at least one separating layer , z. B. Lehmschichte, foil, are separated, in particular for termination of microbiological degradation with malodorous reaction products for at least temporary odor stabilization, optionally for transfer from old landfills, where over gas supply lines targeted air at atmospheric pressure, optionally with further addition of oxygen to the biological substances of a thus forcibly ventilated deposition is guided and withdrawn via gas withdrawal lines gases from the biological substances, in particular aspirated, are essentially consists in that, via the gas supply lines one, in particular at least 5.0 vol .-%, preferably by at least 10.0 vol. -%, low air amount, preferably integrated over minutes, in particular integrated over 5 to 10 seconds, is selectively fed as is extracted via the gas extraction lines as gas quantity, and that, if appropriate, the gas supply lines to the biological substances over the non-selectively acted upon with air organic substances by the gas vent lines is limited. The covered on its side facing the air side with clay or soil landfills, so landfills of biological substances, generally have an anaerobic fermentation. By supplying air in which optionally oxygen enriched, the anaerobic fermentation can be converted into a no odor nuisance having aerobic fermentation. These gases produced during fermentation, are not intended to be supplied directly to the atmosphere, but be gas exhaust pipes, for example, in a biological filter, introduced. By suction of the gases and the air supply, the fermentation is accelerated. Characterized in that a larger amount of air is sucked off is fed as forced is achieved that no arbitrary discharge of the gases takes place from the site, and such a arbitrary outlet includes two major disadvantages. On the one hand would be, especially in the initial phase, a given odor, since the gases escape untreated into the atmosphere, and on the other hand would also be in the early stages of a major threat given due explosions. By the measure delineate the gas supply lines to the biological substances over the non-selectively acted upon with air organic substances by gas discharge lines, it is prevented that gas is expelled in the not forced air landfill by the targeted Luft.zufuhr, but it is also located in the border region maintain a certain negative pressure, so that here no additional gas leaks and thus handicaps occur.

Are the gas supply lines to the biological substances on all sides, is provided by gas discharge lines, in particular for delimitation of the forced air deposition, so in order to ensure a particularly good ventilation within the landfill, since the one hand, the gas pressure is supplied, and this gas is sucked off at adjacent points, in which the other hand, characterized in that the gas feed lines are surrounded by the gas discharge lines ailseitig, ie, for. example, on four sides, it is ensured that no landfill gases are passed into the open air by the introduced gases, but can be supplied via the suction treatment.

If the gas from a deeper horizon vacuumed as the air is supplied, it can be prevented with this simple se measure uncontrolled escape of gases from the landfill, as, in particular malodorous gases are heavier than air.

If the oxygen content of about the gas supply lines fed induced air increased at least once, so can be carried out a steady transfer of anaerobic fermentation in an aerobic fermentation, without toxic effects to cause the inactive present in the landfill aerobically active microorganisms.

If the injection of air or oxygen mixture discontinuously, so growth momentum to accelerate the implementation can be achieved.

If the way of the gas supply lines supplied air laden with water vapor, so it can be ensured that even after weeks of feeding the air, the moisture in the substrate is high enough in dry se landfills which only have a low intake of leachate to a fermentation to ensure.

Are, in particular before the supply of air, via the gas supply lines and / or gas removal lines microorganisms, z. B. suspended in water, supplied to the biological substances, such a vaccination process is given, the z. B. when located long in anaerobic fermentation landfills or even at landfills, in which by exothermic excessive fermentation, the microorganisms have been killed, a further fermentation can be performed.

If on the gas supply lines and / or gas exhaust pipes nutrients, trace elements or the. Like. The accelerated fermentation of biological substances supplied to these, it can be solved in a particularly simple manner, a lack of these substances.

If the temperature of the organic substances and / or the derived gases measured and the supply of air and / or oxygen content controlled afterwards, enabling an optimal degradation behavior are respected, without thereby affecting the microorganisms are killed by high temperatures.

If at exceeding of an upper temperature limit, preferably 50 ° C, in particular 70 ° C, air introduced without further addition of oxygen, whereupon when the temperature drops, in particular below 40 ° C, the oxygen content is increased again, so a particularly high fermentation speed are respected, without causing a destruction of microorganisms which are responsible for the degradation of organic substances, is conditioned.

If if it exceeds an upper temperature limit, preferably 50 ° C, in particular 70 ° C, the extracted gas, enriched with nitrogen and / or carbon dioxide gases, in particular their technical gases via the gas feed lines supplied to the biological substances again, there comes a depleted with oxygen gas so that a very quick drop in the fermentation speed is ensured to the biological substances.

If the extracted gases flared, as is, in particular, where at the beginning of the extraction, a particularly secure disposal of gases.

If the extracted gases discharged through a biofilter to the environment, so in normal operation, a particularly advantageous further odor stabilization of the extracted gases are present because of the existing in the biofilter microorganisms takes place a further microbiological degradation, the present in the biofilter humus due to its ionenaustauscherhaften effect acidic and alkaline substances holds and further serves as adsorbents due to its textured structure.

In the following the invention is explained in more detail with reference to the schematic illustration.

The landfill 1 has a vertical extent of 9 m and is mixed from construction waste, household waste and industrial waste. In order to prevent even a passage of leachates, a sealing layer 2 is provided, which in addition to clay a polypropylene film. The landfill has on its upper surface to a cover 3 of a mixture of earth and clay. The gas supply pipes 4 extend through lead pipes 5 and 6 lances into the landfill. The lances are perforated and serve as Einleitorgane for air into the landfill. The lances can also be arranged at an angle or horizontally as required. The compressor 7, which takes 10 seconds 14.5 Nm³ Air, relative to atmospheric pressure, supplying the landfill, sucks air from the atmosphere and oxygen to discontinuously from a container eighth The air can then be reached in a oil separator, not shown, via a humidifier 9 in the supply lines. 4 The overpressure to the atmosphere can be up to 10 bar, with individual pressure shocks for better penetration of the gases in the landfill at intervals of several seconds can be performed in milliseconds magnitude. In the present example uses an overpressure of 3 to 4 bar. Via the vacuum pump 10, which operates at a pressure of 0.1 bar and 0.6 bar in the conditionally 11 Absauglanzen, 16 Nm³ Gases, based on the atmospheric pressure, suction filtered. The gases then pass into a biofilter 12, in which are arranged essentially biological aerobic rotting substances. The biofilter 12 has a flow rate corresponding to the extracted amount of gas. The drain lines 13 connect the Absauglanzen 11 with the vacuum pump 10, the vacuum pump is a burn-off device is connected downstream of 14th

In carrying out the process of the invention is now to proceed such that, via the Absauglanzen 11, which are positioned lower than the lances 6, present in the landfill gas is exhausted landfill. The pressure in the vacuum pump is about 100 millibars. To ensure a faster suction, can additionally be connected over a part of the lances 6, which are intended for the supply of air and oxygen to the discharge line thirteenth The gases are burned for now on Abfackeleinrichtung 14th At the same time via the compressor 7 air which is passed through the humidifier 9 and via an upstream oil separator is supplied via the gas supply conduit 4 with lances 6 of the landfill. At the same time the gas from now is subtracted from the anaerobic been converted to aerobic fermentation degradation of the organic substances on the Absauglanzen 11 also. This gas now passes through the Biotilter 12 to the environment. Simultaneously, the temperature of the substrate and that of the withdrawn gas is measured. If the temperature of the substrate 50 ° C or at most 70 ° C, then the oxygen supply, soft was added to increase the fermentation container via the oxygen, to the compressor 7, and thus the lances 6, prevented. This oxygen concentration may be .-% oxygen up to an addition of 20 vol. With such an increase in temperature, the additional supply of oxygen is on the one hand interrupted. If a further reduction in the reaction rate desired, the vacuum pump 12 can be connected to the compressor 7 so that the extracted gases are introduced again in the landfill, so that the oxygen content of the introduced into the landfill gases may be contrasted with the air still further lowered , After reaching the desired temperature can be reinitiated normal air or air with the addition of oxygen in the landfill. Instead of the extracted gases can technically pure nitrogen or carbon dioxide occur.

If the fermentation does not start or interrupts the desired extent, it is possible that either a lack of certain nutrients or trace elements has led to a slowdown in the growth of microorganisms, or that died for other reasons, in particular due to high temperature, the microorganisms are. In this case, the supply of nutrient solutions, and possibly also trace element solutions or suspensions of microorganisms can be carried out both on the suction as well as the supply lines, which after a short time trouble-free operation is achieved.

After appropriate rerouting the anaerobic fermentation in an aerobic fermentation odor stabilization of the landfill has occurred, so that a mechanical degradation thereof can be carried out with subsequent seduction, with a slight reduction of the landfill is possible. If no seduction is desired, an accelerated completion of the entire fermentation and thus explosion and odor can be achieved.

Is now about 2 to 3 weeks odor stabilization achieved in the landfill, so both the lances for the air supply as well as for the extraction of the gases can be added and can be converted into a new not yet treated field of landfill. The freed from the pipelines landfill can then be mechanically broken down, the fine fraction can be utilized as humus. The transfer is made such that the air supply is separated by gas extraction lines as a delimitation of the air supply with respect to the not yet treated and ventilated landfill. The Gasabzugs- or supply lines in the landfill can through perforated pipes, wells, which are filled with gravel or other suitable means may be formed.

In the formation of the pipes must be taken into account, that the higher the negative pressure in a pipeline, the higher must be the mean free path of the molecules, and thus the greater the cross-section of the pipes. If this approach does not take into account, as it comes at a very rapid pressure drop within the vacuum gas lines. The material of the air supply lines is not particularly chemical stresses, so that there is common materials may be used. However, extracted from the landfill gases may be chemically aggressive, for example, contain acidic components, so that an appropriate choice of materials is to be met if the devices come in the longer term to use.

For seeding with microorganisms, aqueous extracts from aerobic rotting material such. B. od humus. Like. Or be produced from the present in the biofilter substances.

The gas vent lines may have explosion doors, to avoid destruction of the system in case of malfunctions.

For regulating the pressure in the lances remotely controlled manually or automatically before the same adjustable valves may be provided. In the lances for sucking devices also may be provided within the lances to adjust the cross-sectional openings, through which the suction takes place, for. Example in the form of a rotary valve.

To impetus for growth of microorganisms and thus contribute to the accelerated conversion of the organic substances, the blowing of air or oxygen mixture z. B. can discontinuously, intermittently, slowly or rapidly increasing in the flow rate, can be performed.