DE102009025470A1 - Method for aerating static decayed debris e.g. waste dump, involves introducing oxygen as oxygen carrier into waste body by hydrogen peroxide dissolved in water, where concentration of hydrogen peroxide solution amounts to specific range - Google Patents

Abstract

The method involves introducing oxygen as an oxygen carrier into a waste body by hydrogen peroxide dissolved in water. Concentration of the hydrogen peroxide solution amounts to more than 5 percent of mass and less than 20 percent of mass. An aqueous solution such as landfill leachate or landfill leachate concentrate, is used as a solvent for the hydrogen peroxide. The oxygen carrier is fed and drained by gravity to the waste body. A registered amount of fluid is controlled using technical devices such as control valves and flow meters.

Description

1) Name of the invention

Process for the aerobization of dormant Abfallhaufwerken

2) Technical field of the invention

waste Management

3) The technical problem underlying the invention

The in dormant waste streams (eg landfills, old deposits, interim storage) contained organic matter is caused by anaerobic microorganisms within long periods of time (up to several hundred years) reduced. This will be flammable, harmful and odor-intensive landfill gas, and especially organically polluted Leachate released. Both streams require until the biological processes have sufficiently decayed Registration and treatment.

Around shorten this period, it is possible to the environment in the landfill body by the entry of oxygen to aerobize - aerobic-microbiological processes take place much faster than anaerobic, they also do not form a flammable Gas and no bad odors.

at the usual aerobization techniques become the waste body ventilated by putting in this atmospheric air blown or occasionally sucked through. The for The microbial respiration needed oxygen must be in from the air pass over the pore water, since microorganisms only in water can absorb dissolved oxygen. The ventilation of waste debris is therefore described in point 4 Disadvantages connected by the use of the invented method can be avoided.

4) State of the art and its shortcomings

Of the Prior art concerning aerobization of biologically active Waste heaps currently consist exclusively of the deposited waste by means of various technical devices with gaseous oxygen, usually as part of air, to flow through.

• a) Für die Einbringung von Luft sowie für die Absaugung des Abgases sind Installation und Betrieb aufwendiger technischer Anlagen notwendig.
• b) Sauerstoff kann nur in gelöster Form von Mikroorganismen verwertet werden, löst sich jedoch schlecht in Wasser. Für einen zufriedenstellenden Stoffübergang ist eine möglichst große Grenzfläche zwischen Gas- und Wasserphase erforderlich – dies wird durch das einfache Einblasen von Luft nicht gewährleistet. Der Sauerstoff wird folglich nicht effizient genutzt, weshalb ein großer Teil des eingeblasenen Sauerstoffs wieder an die Atmosphäre abgegeben werden.
• c) Der nicht nutzbare Stickstoff (79 Volumen-%), sowie der erforderliche Überschuss an Luft durchströmen den Abfallkörper und verlassen ihn gesättigt mit Wasser, und angereichert mit Deponiegasbestandteilen, so zum Beispiel mit Methan, Schwefelwasserstoff, Ammoniak, organischen Stickstoff- und Schwefelverbindungen sowie niederen organischen Säuren. Das so generierte schädliche und geruchsintensive Abgas muss zum Beispiel mittels Gasbrunnen und Saugzuggebläse erfasst und in der Folge biologisch, thermisch oder adsorptiv behandelt werden.
• d) Durch den ständigen Austrag von Wasserdampf droht der Abfallkörper auszutrocknen, und die erwünschten biologischen Prozesse zu erliegen. Es muss folglich das Haufwerk ständig kontrolliert bewässert werden.
• e) Wegen der Inhomogenität und der groben Stückigkeit des Abfalls sucht sich das eingeblasene Gas den Weg des geringsten Widerstandes. Folge hiervon sind Channelling- Effekte, d. h. es bilden sich gut mit Sauerstoff versorgte Kanäle, sowie verschieden große Zonen, welche nicht von der Luft erreicht werden, und welche folglich anaerob bleiben. Channelling ist ein bekanntes Problem bei der Durchströmung poröser Medien, und ist schwer zu vermeiden.
• f) Die meisten Belüftungsverfahren können nur bei komplett abgedichteten Deponien sinnvoll eingesetzt werden, damit die Erfassung des Abgases möglich ist.

Most venting methods are based on the following principle: By means of compressors, air is blown into the partially or completely sealed waste body, for example via ventilation lances, whereby part of the atmospheric oxygen can dissolve in the pore water of the waste, allowing aerobic microorganisms to breathe. However, all of the atmospheric nitrogen and most of the oxygen must leave the waste body elsewhere. To control this process, the exhaust gas is sucked off, for example, over existing gas wells by means of induced draft blowers. From this procedure lead to the following disadvantages for all ventilation methods:

• a) Installation and operation of complex technical equipment is necessary for the introduction of air and for the exhaust gas extraction.
• b) Oxygen can only be utilized in dissolved form by microorganisms, but dissolves poorly in water. For a satisfactory mass transfer the largest possible interface between gas and water phase is required - this is not guaranteed by the simple injection of air. The oxygen is therefore not used efficiently, which is why a large part of the injected oxygen are returned to the atmosphere.
• c) The unusable nitrogen (79% by volume), as well as the required excess air flow through the waste body and leave it saturated with water, and enriched with landfill gas components, such as methane, hydrogen sulfide, ammonia, organic nitrogen and sulfur compounds and lower organic acids. The harmful and odorous exhaust gas generated in this way must, for example, be detected by means of gas wells and induced draft blowers and subsequently treated biologically, thermally or adsorptively.
• d) Through the constant discharge of water vapor threatens to dry out the waste body, and succumb to the desired biological processes. Consequently, the debris has to be irrigated constantly.
• e) Because of the inhomogeneity and the gross lumpiness of the refuse, the injected gas seeks the path of the least resistance. This results in channeling effects, ie well oxygenated channels are formed, as well as zones of different sizes, which are not reached by the air, and which consequently remain anaerobic. Channeling is a known problem in the flow of porous media, and is difficult to avoid.
• f) Most of the ventilation methods can only be used sensibly in completely sealed landfills, so that the capture of the exhaust gas is possible.

In Germany, the so-called low pressure ventilation is used as aerobicization measure at some locations. One such variant is the one under the file number DE 100 05 243.6 patented four-stage in situ stabilization using low pressure ventilation. A typical aeration pressure is about 50 hectopascals. The above described not agile extraction and treatment of the exhaust air is part of the patent.

Further examples of aeration techniques can be found in the relevant specialist literature: inter alia in TOWNSEND, TG ET AL. (2004) is described above all developed in the US and industrially realized bioreactor process. It is a combined process with which a landfill can be operated aerobically or anaerobically as needed. Depending on the injection depth, air is injected at operating pressures of up to 500 hPa for the occasional aerobization. A relatively high energy input is the result. The generated, loaded with harmful gases and odors exhaust is sucked off and treated. In general, the method is characterized by a high expenditure on equipment.

A similar one to the above mentioned methods is also described in the literature COSSU, R. ET AL. (2003) described.

Also known is the so-called semiaerobic technique with passive entry of oxygen through the chimney effect by high temperatures in the waste body (see, inter alia MATSUFUJI, Y. ET AL., 2005 ). Again, the gas detection and treatment described above is mandatory.

For All these methods come the disadvantages listed above to carry.

5) solution of the defects by the invention and embodiments

The The invention is capable of effectively handling dormant debris Oxygen supply - effective above all concerning the utilization of the introduced amount of oxygen, and concerning it Distribution in the waste body.

The Invention takes advantage of the fact that aerobic and facultative anaerobic microorganisms have an enzyme (catalase), which after a certain adaptation time in the presence of amplified dissolved in water peroxidized compounds is excreted, and which then spontaneously to oxygen and water (in the case of hydrogen peroxide) or a corresponding residual molecule (with other peroxides) decomposes. The released oxygen becomes in the choice of an adequate peroxide concentration in the used solution largely dissolved in the water present.

The Invention provides a commercially available solution of hydrogen peroxide in an occupational safety controllable Concentration in the waste to be aerobized in free fall to infiltrate or otherwise contribute.

For The infiltration will be filled with peroxide solution Containers at a suitable, ideally highest Point of the pile set up. There are the containers connected to a pipe network, which the draining liquid in appropriate infiltration facilities directs. For infiltration can be unused gas wells, specially drilled or already existing sump wells, existing multi-storey trenches (eg for leachate pure filtration), subsequently built-in one-level trenches or other suitable devices are used. The solution becomes convective following gravity, as well as diffuse in the waste body to distribute. The distribution efficiency is mainly due to the Type of infiltration devices and their distances from one another certainly. The volume flow of the oxygen carrier is through controlled and controlled appropriate technical devices. at More compacted heaps can improve the flow-through pumps are used.

It For example, the added amount of solution may be at the local However, if necessary also take into account the leachate quality and quantity of the heap. These, in turn, depend, among other things, on the degree of compaction of the garbage and the proportion of the surface covered.

alternative The peroxide solution can also be leached using lances be introduced into the waste body.

As soon as the solution comes into contact with the waste, starting facultative anaerobic microorganisms, according to the o. e. Adaptation time, the peroxide to split, causing the microorganisms immediately and immediately dissolved Oxygen is available for breathing.

• a) Aus organischen Kohlenstoffverbindungen, sowie aus im Porenwasser gelösten niedermolekularen Verbindungen wie niedere Fettsäuren, organische Stickstoff- und Schwefelverbindungen, werden in CO₂-Gas, Wasser, Sulfat- und Nitrat-Anionen gebildet.
• b) Ammoniak und Ammonium werden zu Nitrat oxidiert.
• c) Schwefelwasserstoff wird zu Sulfat oxidiert.
• d) Im Porenraum vorhandenes Methan wird zu gasförmigem CO₂ und Wasser umgesetzt.

Excess gaseous oxygen is not discharged from the system when adequate peroxide concentrations are used. As aerobic-biological processes begin, the following processes take place in waste:

• a) From organic carbon compounds, as well as from dissolved in pore water low molecular weight compounds such as lower fatty acids, organic nitrogen and sulfur compounds are formed in CO ₂ gas, water, sulfate and nitrate anions.
• b) Ammonia and ammonium are oxidized to nitrate.
• c) Hydrogen sulphide is oxidised to sulphate.
• d) Methane present in the pore space is converted to gaseous CO ₂ and water.

During the initial period, in which with the very low gas flow noxious gases and If necessary, the gas can be detected and treated with suitable equipment. In the stable state of the system, the discharge of noxious gases is negligible.

6) Advantages achieved by the invention over the prior art

• a) For the use of the invention a considerably lower technical effort than in the state of Technology necessary.
• b) Almost 100% of the registered oxygen can be absorbed by the Microorganisms are used - in the prior art the proportion used is much lower.
• c) A gas surplus is not registered, thus the exhaust gas flow is so low that it does not catch and treat must become.
• d) There is no risk of dehydration of the waste body.
• e) Uneven oxygen distribution through channeling effects does not take place.
• f) The method can be applied to both sealed, covered, as well as in open to the atmosphere heaps used be - in the prior art is due to be expected Gas emissions at least a cover of the waste body required.

7) Cited patents and non-patent literature

• PATENT DE 100 05 243.6
• TOWNSEND, TG ET AL. (2004): "Update to New River Regional Landfill Bioreactor Project" Lecture at the SWANA Landfill Symposium, Monterey, USA, June 21-25, 2004 ,
• COSSU, R. ET AL. (2003): "Full Scale Application of In Situ Aerobic Stabilization of old Landfills" in: Proceedings Sardinia 2003, Ninth International Waste Management and Landfill Symposium. Cagliari, Italy, 6-10 October 2003 ,
• MATSUFUJI, Y. ET AL. (2005): "Biodegradation process of municipal solid waste by semiaerobic landfill type", in: Proceedings Sardinia 2005, Tenth International Waste Management and Landfill Symposium, S. Margherita di Pula, Cagliari, Italy, 3-7 October 2005 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10005243 [0006]

Cited non-patent literature

• - TOWNSEND, TG ET AL. (2004) [0007]
• - COSSU, R. ET AL. (2003) [0008]
• MATSUFUJI, Y. ET AL., 2005 [0009]

Claims (10)

A method for the aerobization of dormant waste heaps, characterized in that oxygen is introduced via dissolved in water hydrogen peroxide (H ₂ O ₂ ) as an oxygen carrier in the waste body. A method according to claim 1, characterized in that the concentration of the H ₂ O ₂ solution may be between 3 and 50% by mass, preferably more than 5% by mass and less than 20% by mass. Process characterized in that as the solvent other aqueous solutions for the peroxide, such as landfill leachate or landfill leachate concentrate can serve. A method characterized in that to be aerobized Abfallhaufwerke a) in operation or in the aftercare phase, sealed, inter-sealed, covered or open to the atmosphere Landfills for the disposal of municipal waste or waste with shares in municipal waste, b) temporary storage for municipal waste, c) old deposits of waste of all kinds, as well d) heaps of biological Treatment of municipal waste or other organic Material containing waste could be. Process characterized in that the oxygen carrier without the use of pumps in free fall the waste body can be supplied and infiltrated. Method according to claim 5, characterized that the amount of liquid entered through the use of suitable technical devices, such as control valves and flow meters, can be controlled. Method according to claim 5, characterized that the infiltration of the oxygen carrier by means of use can be improved or accomplished by pumps. Method characterized in that as infiltration devices a) no longer used gas wells, b) for the purpose of gas-free oxygen supply specially built or existing vertical mouth, c) specifically for the purpose the gas-free oxygen supply or for other purposes erected multi-storey trenches (horizontal wells), d) for the purpose of gas-free oxygen supply or for other purposes built shallow one-storey trenches, e) other suitable infiltration devices as well to the Use can come. Method according to claim 5, characterized that the peroxide solution via lances in the waste body can be pumped. Method characterized in that at the beginning aerobic gas when it produces harmful substances releases odors to a significant degree, recorded and treated in a suitable way.