Process System for Reclaiming a Sustainable Landfill and Fuelizing Combustibles from Landfill Waste

Abstract

The present invention relates to a process system for reclaiming a sustainable landfill and fuelizing combustibles from the landfill waste. According to the present invention, the odor and landfill gas in the landfill are removed, and then the organic matters in the landfill waste are pre-stabilized so that the moisture of the landfill waste is partially reduced, the landfill waste which went through the odor stabilization and the pre-stabilization is excavated and sorted, and then the purity of the sorted landfill waste is increased for recycling and fuelizing, solid fuels are produced from the collected combustibles, thereby it is allowed to recycle resources and manage land efficiently due to circulating use of operating or closed landfills.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process system for reclaiming a sustainable landfill and fuelizing combustibles from landfill waste, and more particularly, to a process system configured to mechanically sort landfill waste, which went through odor stabilization and pre-stabilization, so that collected soil is reused as a cover material and solid fuels (fluff RDF: Refuse Derived Fuel) are produced from collected combustibles through drying and fuelizing treatments.

2. Background of the Related Art

So as to achieve the reduction of greenhouse gas emission and the growth of the virtuous circle between economy and environment, recently, ‘Low Carbon and Green Growth’ strategies and laws have been proposed in many countries, and many endeavors whereby fossil fuels are replaced with renewable energy are conducted to decrease the greenhouse gas emission.

According to the Korean government's plans, the renewable energy supply rate to total domestic energy supply amount will be increased to 3.78% by 2013, and through the dynamic utilization of waste resources and bio-mass, further, it will be more increased to 6.08% by 2020 and 11% by 2030. The rate of the waste energy from the domestic renewable energy is 76%, and the renewable energy will be efficiently distributed and supplied from municipal waste and landfill waste. Accordingly, ‘waste resources and bio-mass energy plan’ and ‘green technology research and development plan’ are published by the Ministry of Environment in Korea (in 2009), and together with the existing method of sanitarily and stably treating the municipal waste from households and the like, thus, the development for green technology by which waste is turned into a resource or new energy becomes focused.

According to the recent report of IPCC (Intergovernmental Panel on Climate Change), especially, about 5% of the emission rate of the greenhouse gas considered as one of main causes of world environmental problems is occupied by waste, so that new management for the waste should be needed. More particularly, if the municipal waste from households and the like is landfilled unsanitarily, the environmental pollution materials such as landfill gas (for example, greenhouse gas like CH₄ and CO₂) and leachate generated from the landfill cause serious environmental pollution of the air, water and soil as well as global warming, and therefore, there is a definite need for the development of new policy and technology capable of effectively processing the landfill waste.

According to the research result of the Ministry of Environment in Korea, on the other hand, the number of closed landfills is about 1,238 in 2005, and in this case, most of the closed landfills are old landfills having no waterproofing equipment. Among them, 186 landfills over 500,000 m3 have been selected and treated intensively as priority management landfills, and urgent management for the landfills is needed. As a result, closed landfill reclamation plan was published in December 2001 by the Ministry of Environment in Korea, and based upon the plan, closed non-sanitary landfills having serious degrees of environmental pollution are selected and reclaimed by step under the support of the national treasury. The combustibles sorted from the landfills are just burnt, and the reclaimed landfills are reused as parks and housing sites. In this case, however, waste resources are unfortunately lost through the process for just burning the combustibles.

Further, the number of operating landfills is drastically decreased from about 623 in 1990 to about 285 in 2001, and it is continuously reduced to 226 in 2009.

According to the research results of residual capacity of landfills except the landfills in capital areas, the residual capacity becomes decreased continuously year by year, as shown in

FIG. 4, and based on the standard of landfill amount per year, as shown in FIG. 5, 113 landfills corresponding to about 51% of the total landfills will be closed in use within 9 years by 2018, As the dumping of organic waste at sea will be prohibited in 2013, especially, the landfill amount will be additionally increased, such that small scale landfills except large scale landfills become more rapidly decreased in their usage term than the above-mentioned period.

Especially, in case of local governments that necessarily require landfill systems due to the economical infeasibility of mechanical biological treatment (MBT) facilities for achieving waste-to-energy planned and developed by the central Government and in case of local governments that operate 89 small scale landfills (about 39.4% of the total landfills) of less than 10,000 m2, the construction of new landfills and incineration facilities are considered to sufficiently secure the residual capacities of the landfills. However, because of a variety of problems such as the increase in the construction cost of the new landfills, NIMBY (not in my back yard), the difficulties in securing new landfill sites, and the reduction in the national treasury support for environmental infrastructure such as landfills and incinerators and so on, it is actually hard to build new landfills and incinerators, such that municipal waste treatment will be one of serious social problems in the near future.

However, according to domestic landfill reclamation technology adopted to closed non-sanitary landfill reclamation business conducted on the basis of ‘closed landfill reclamation guides’ proposed by the Ministry of Environment in Korea on December 2001, combustibles are just sorted from non-sanitary landfill waste in which an amount of combustibles is small and an amount of non-combustibles like soil is large. Therefore, the conventional technology cannot be applied to collecting combustibles in high purity from the sanitary landfill waste in which an amount of combustibles is large and an amount of non-combustibles like soil is small.

In some cases, particularly, the landfill waste is excavated and sorted to conduct the landfill reclamation on landfill site, but there has been no case in which the combustibles are sorted in high purity on the landfill site and high quality of auxiliary fuels like cement are produced from them, without any movement to the outside of the landfill site, so as to achieve waste-to-energy according to the ‘Low Carbon and. Green Growth’ strategy proposed by the Korean Government. Also, the lack in the number of landfills commonly appears in many countries such as Japan, China, Brazil, the United States of America, and so on, and as the need of renewable energy should be definite due to the limit of the fossil energy, circulating use of landfills and making energy with the sorted combustibles become one of very attractive studies and businesses.

Accordingly, it is timely research to develop new technology by which the operating or closed sanitary landfills are circulatingly used to make up for the number of the landfills lacking in the local governments, the environmental pollution like landfill gas, leachate and so on are reduced, the sorted soil is recycled as cover materials upon the operation of the landfill in the future, and combustibles are sorted in high purity so as to produce high quality of solid fuels from them as replacement of fossil energy, since the new technology satisfies the ‘Low Carbon and Green Growth’ strategy inclusive of the development of renewable energy and the reduction of the greenhouse gas emission, proposed by the Korean Government.

According to a conventional process for sorting and recycling waste from a landfill, as shown in FIG. 1, the landfill waste is injected into an injection hopper, and the landfill waste is sorted through a trommel screen device to separately supply soil and combustibles to a soil sorter and a combustible sorter. Next, the soil sorter separates the soil into sorted soil and organic foreign matters, and the combustibles sorter separates the combustibles into sorted combustibles and non-combustibles. That is, the landfill waste for which odor stabilization has been conducted is sorted mechanically, so that only a portion of the collected soil is used as fill material and the combustibles are just incinerated, thereby causing the increase of the treatment costs and the consumption of energy.

So as to solve the problems in such conventional process, thus, there has been proposed Korean Patent No.10-0492810 entitled method and device for recycling combustible waste obtained during landfill reclamation or restoration as fuels for cement process. However, since the prior art relates to the method and device wherein the combustibles are injected into a slant continuous kiln in a cement pyro process, in which combustion is conducted up to a material temperature of 1450° C. and a gas temperature of 2000° C., and the ashes generated are made to a product like clinker or cement, it is actually different from the process for excavating and sorting waste from the landfill and producing solid fuels (fluff RDF) from the sorted combustibles.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a process system for reclaiming a sustainable landfill and fuelizing combustibles from landfill waste, configured to excavate and sort landfill waste, for which odor in the landfill and of the landfill gas has been stabilized and pre-stabilization has been performed, so that the collected soil is reused as a cover material and solid fuels (like fluff RDF) are produced from the combustibles through drying and fuelizing treatment.

To accomplish the above object, the present invention comprising: means for performing a landfill waste odor stabilization and pre-stabilization process of removing odor and landfill gas in the landfill, pre-stabilizing the organic matters in the landfill waste, and partially reducing moisture of the landfill waste; means for performing a landfill waste excavating and sorting and combustibles purity increasing process of excavating and sorting the landfill waste, which went through the odor stabilization and pre-stabilization process, and increasing the purity of the product sorted from the landfill waste so as to recycle and fuelize the sorted product; and means for performing a landfill combustibles fuelizing process of producing solid fuels (Fluff RDF) from collected combustibles, so as to use operating or closed landfills circulatingly and fuelize the landfill combustibles.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing a conventional system for sorting and recycling landfill waste;

FIG. 2 is a photograph flowchart about a process system for reclaiming a sustainable landfill and fuelizing combustibles from landfill waste according to the present invention; and

FIG. 3 is a process chart about the process system for reclaiming a sustainable landfill and fuelizing combustibles from landfill waste according to the present invention.

FIG. 4 is a graph showing variations of the number of operating landfills and landfill residual capacities by year.

FIG. 5 is a graph showing landfill capacity by the scale of landfill.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, an explanation on a process system for reclaiming a sustainable landfill and fuelizing combustibles from landfill waste according to the present invention will be given with reference to the attached drawing.

FIG. 2 is a photograph flowchart about a process system for reclaiming a sustainable landfill and fuelizing combustibles from landfill waste according to the present invention, and FIG. 3 is a process chart about the process system for reclaiming a sustainable landfill and fuelizing combustibles from landfill waste according to the present invention.

As shown in FIGS. 2 and 3, according to the present invention, there are provided processes for reclaiming a sustainable landfill and fuelizing combustibles from landfill waste, the processes including a landfill waste odor stabilization and pre-stabilization process of removing odor and landfill gas in the landfill in which landfill waste is buried, pre-stabilizing the organic matters in the landfill waste, and partially reducing moisture of the landfill waste; a landfill waste excavating and sorting and combustibles purity increasing process of excavating and sorting the landfill waste, which went through the odor stabilization and pre-stabilization process, and increasing the purity of the product sorted from the landfill waste so as to recycle and fuelize the sorted product; and a landfill combustibles fuelizing process of producing solid fuels (like Fluff RDF) from collected combustibles, so as to use operating or closed landfills circulatingly and fuelize the landfill combustibles.

The processes for reclaiming sustainable landfill and fuelizing combustibles from landfill waste including such processes and will be described in more detail.

In the landfill waste odor stabilization and pre-stabilization process, the odor and landfill gas in the landfill in which burial of landfill waste has been closed are removed and moisture is dried. At this time, the landfill gas is emitted to the outside through pipes planted into the landfill, and the emitted landfill gas is filtered through a filtering device outside.

At this time, the moisture contained in the landfill waste is partially dried by blowing air through these pipes so as to aid performing next processes, and the odor emitted from the landfill waste is partially removed by directly spraying a deodorizer.

The landfill waste excavating and sorting and combustibles purity increasing process is performed by: an injection hopper into which the landfill waste excavated from the landfill by means of heavy equipment is injected; a magnetic sorting device adapted to primarily sort metals from the landfill waste injected into the injection hopper so as to recycle the sorted metals; a trommel screen device adapted to downwardly discharge soil less than 35 mm contained in the landfill waste from which the metals have been primarily sorted; a mechanical precision sorting device for soil adapted to discharge soil of 15-20 mm from the soil less than 35 mm discharged from the trommel screen device so as to recycle the discharged soil; and a mechanical precision sorting device for combustibles adapted to precisely sort the combustibles as an object of solid fuel from the landfill waste from which the soil less than 35 mm has been discharged by the trommel screen device.

Each of the trommel screen device and the mechanical precision sorting device for soil is formed of rotatable cylindrical screen drums having a plurality of holes of 35 mm or 15-20 mm on the outer periphery thereof, so that the soil less than 35 mm contained in the landfill waste is supplied through the trommel screen device to the mechanical precision sorting device for soil positioned below, and the soil of 15-20 mm is passed downwardly through the mechanical precision sorting device for soil, discharged being separated into soil and non-combustibles, and recycled.

At this time, the soil not passed through the holes of 15-20 mm of the mechanical precision sorting device for soil is discharged separately as organic foreign matters by a rake-type sorting device of the mechanical precision sorting device for soil and buried in the landfill.

The mechanical precision sorting device for combustibles has a type of rake so as to sort the combustibles in sequential order from large volumes to small volumes, so that the combustibles are precisely sorted as the object of solid fuel and the non-combustibles not sorted through the mechanical precision sorting device for combustibles is separated for recycling.

The landfill combustibles fuelizing process is performed by: a combustibles purity increasing device adapted to be supplied with the combustibles sorted as the object of solid fuel and to dry the soil on the combustibles by applying hot air thereto so as to discharge the soil on the combustibles for recycling; a magnetic sorting device adapted to secondarily sort the metals contained in the combustibles, which has been dried and from which the soil has been separated, for recyling; a crusher adapted to crush the combustibles, from which the metals have been secondarily sorted, to 100-150 mm; a mill adapted to grind the combustibles crushed through the crusher to 30-50 mm; and a solid fuel packaging device adapted to compress the combustibles grinded to 30-50 mm to solid fuels at the inside thereof and to package the solid fuels.

The combustibles purity increasing device is formed of a rotatable cylindrical screen drum having a plurality of holes on the outer periphery thereof, and dries the soil on the combustibles by means of a hot air generator mounted at the inside thereof so as to separately discharge the soil on the combustibles for recycling.

The solid fuel packaging device is supplied with the combustibles grinded to 30-50 mm, compresses the combustibles to the solid fuels at the inside thereof, and packages the solid fuels to a given size.

Now, schematic operations on this process system for reclaiming a sustainable landfill and fuelizing combustibles from landfill waste according to the present invention will be explained.

As shown in. FIGS. 2 and 3, a pre-stabilization process for landfill waste is performed before the landfill in which burial of waste has been closed is excavated.

In this landfill waste odor stabilization and pre-stabilization process, the landfill gas is emitted to the outside through the pipes planted into the closed landfill, the emitted landfill gas is filtered outside, the moisture contained in the landfill waste is partially dried by blowing air through these pipes so as to aid performing next processes, and the odor emitted from the landfill waste is partially removed by directly spraying the landfill with the deodorizer.

When the landfill waste odor stabilization and pre-stabilization process is finished, the landfill waste is excavated by means of heavy equipment like a backhoe, delivered by a dump truck, injected into the injection hopper, and supplied to the magnetic sorting device through which metals are primarily sorted. At this time, the primarily sorted metals are treated for recycling.

After that the landfill waste from which the metals have been primarily sorted is supplied to the trammel screen device which is rotatable and formed, of a net having holes of 35 mm, the soil less than 35 mm contained in the landfill waste discharged from the trommel screen device is supplied to the mechanical precision sorting device for soil positioned below, and the soil of 15-20 mm is discharged through the mechanical precision sorting device and treated for recycling.

At this time, the soil not passed through the holes of 15-20 mm of the mechanical precision sorting device for soil is discharged separately as organic foreign matters by the rake-type sorting device of the mechanical precision-sorting device for soil.

Next, the landfill waste from which the soil less than 35 mm has been discharged through the trommel screen device is supplied to the mechanical precision sorting device for combustibles, and the combustibles are precisely sorted as the object of solid fuel through the mechanical precision sorting device for combustibles. At this time the non-combustibles not sorted through the mechanical precision sorting device for combustibles are separated for recycling.

Next, the combustibles sorted as the object of solid fuel are supplied to the combustibles purity increasing device formed of the rotatable cylindrical screen drum having holes on the outer periphery thereof, the soil on the combustibles is dried by means of the hot air from the hot air generator mounted at the inside of the combustibles purity increasing device and is separately discharged for recycling, thereby the purity of the combustibles is increased.

After that, the combustibles of which purity has been increased are supplied to the magnetic sorting device, the metals contained in the combustibles are secondarily sorted through the magnetic sorting device and treated for recycling, the combustibles are then supplied to the crusher and crushed to 100-150 mm, the crushed combustibles are grinded to 30-50 mm through the mill and then supplied to the solid fuel packaging device, the grinded combustibles are compressed to solid fuels at the inside of the solid fuel packaging device, and the compressed solid fuels are packaged and stacked, thereby one process is completed.

According to the present invention, the odor and landfill gas in the landfill are removed, and then the organic matters in the landfill waste are pre-stabilized, so that the moisture of the landfill waste is partially reduced, the landfill waste which went through the odor stabilization and the pre-stabilization is excavated and sorted, and then the purity of the sorted landfill waste is increased for recycling and fuelizing, solid fuels are produced from the collected combustibles, thereby it is allowed to recycle resources and manage land efficiently due to circulating use of operating or closed landfills.

The preferable embodiments of the present invention explained above are described with the purpose of example and may be modified, changed, or added variously under the technical idea and the scope of the present invention. These modification, change, and addition have to be regarded as belonging to the appended claims.

Claims

1. A system for reclaiming a sustainable landfill and fuelizing combustibles from landfill waste, the system comprising:

means for performing a landfill waste odor stabilization and landfill waste pre-stabilization process of removing odor and landfill gas in the landfill and reducing moisture of the landfill waste;

means for performing a landfill waste excavating and sorting and combustibles purity increasing process of excavating and sorting the landfill waste, which went through the odor stabilization and pre-stabilization process, and increasing the purity of the product sorted from the landfill waste so as to recycle and fuelize the sorted product; and

means for performing a landfill combustibles fuelizing process of producing solid fuels (fluff RDF) from collected combustibles.

2. The system according to claim 1, wherein the means for performing landfill waste excavating and sorting and combustibles purity increasing process comprising:

a magnetic sorting device adapted to primarily sort metals from the landfill waste injected into an injection hopper after excavating the landfill waste;

a trommel screen device adapted to downwardly discharge soil less than 35 mm contained in the landfill waste from which the metals have been primarily sorted;

a mechanical precision sorting device for soil adapted to discharge soil of 15-20 mm from the soil less than 35 mm discharged from the trammel screen device; and

a mechanical precision sorting device for combustibles adapted to precisely sort the combustibles as an object of solid fuel from the landfill waste from which the soil less than 35 mm has been discharged by the trommel screen device.

3. The system according to claim 2, wherein the mechanical precision sorting device for soil is formed of a rotatable cylindrical screen drum having holes of 15-20 mm and has a rake type sorting device provided on one side thereof so as to separately discharge the soil not passed through the holes of 15-20 mm to the outside.

4. The system according to claim 1, wherein the means for performing a landfill combustibles fuelizing process comprising:

a combustibles purity increasing device adapted to be supplied with the combustibles separated as the object of solid fuel and to dry the soil contained in the combustibles by applying hot air thereto so as to separately discharge the soil on the combustibles;

a magnetic sorting device adapted to secondarily sort the metals contained in the combustibles which has been dried and from which the soil has been separated;

a crusher adapted to crush the combustibles, from which the metals have been secondarily sorted, to 100-150 mm;

a mill adapted to grind the combustibles crushed through the crusher to 30-50 mm; and

a solid fuel packaging device adapted to compress the combustibles grinded to 30-50 mm to solid fuels at the inside thereof and to package the solid fuels.

5. The system according to claim 4, wherein the combustibles purity increasing device is formed of a rotatable cylindrical screen drum having a plurality of holes, and dries the soil on the combustibles by means of a hot air generator mounted at the inside thereof so as to separately discharge the soil on the combustibles.