Hydraulic and earth engineering – Subterranean waste disposal – containment – or treatment – Compacting
Reexamination Certificate
2000-04-05
2003-05-06
Lee, Jong-Suk (James) (Department: 3673)
Hydraulic and earth engineering
Subterranean waste disposal, containment, or treatment
Compacting
C405S129200, C405S129750, C405S129900, C405S129950
Reexamination Certificate
active
06558079
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a method and apparatus for laying a film on a landfill, and more particularly to a method and apparatus for compacting the landfill, spraying a pesticide upon the compacted waste, laying film over the landfill, and depositing ballast on the film.
2. Description of the Related Art
Landfills have become highly regulated in recent years with an emphasis on minimizing their impact to surrounding populations and the environment. Regulatory agencies, like the Environmental Protection Agency of the United States, mandate requirements for landfill design and maintenance in an attempt to minimize the potential for odors, ground water contamination, fires, blowing litter, disease vectors, and vermin infestation. In an attempt to prevent such undesirable occurrences, regulatory agencies have adopted strict restriction and codes as to the construction and covering of landfills.
Often, new landfills are created with a liner constructed of a polymeric film to cover the bottom of the landfill to prevent ground water contamination and disease vectors. The liner is used to prevent seepage from the waste stored on top of the liner from entering into the community water table located underground. Most often, the liner is installed by overlapping sections of film laid along the bottom of the recently excavated landfill and heat sealing the sections together to ensure that no liquid seeps through the liner between the panels of film and into the virgin ground underneath the landfill. It is preferred that such a liner have a long life expectancy and not degrade so that the water table may be separated from the landfill for as long as possible. Once the liner and a required minimum soil cover has been deposited over the base of the landfill, waste materials can then be accepted onto the landfill for disposal.
Landfill covers are required by regulatory agencies for landfill sections that are to be left inactive for extended periods of time or at the end of every workday. Regulatory agencies require exposed waste to be covered in order to reduce the effects of fires, odor, vermin, litter, and disease on nearby populations. It is understood that the open face of a landfill is the surface of compacted trash and garbage, much enclosed in plastic bags, and other waste, but can also contain tree pieces, cans, small appliances, wood, shingles, building materials of all kinds, dirt, sludge, or any other material permitted in a landfill. Traditionally, soil was used as the primary means of cover and was applied upon deposited waste in amounts governed by how long the section of the landfill as to remain inactive.
Many current regulations require daily coverage of exposed waste with the daily cover including a minimum of six (eight in some locations) inches of soil applied to the landfill workface. Due to the non-homogeneous layout of most landfills, such a layer of soil may actually reach from 12 to 15 inches in height in certain areas in order to ensure that the six inch minimum exists throughout. Careful planning and management must be applied to each landfill installation to ensure that the utility of the available airspace is maximized. For this reason, landfills are preferably filled in sections, rather than all at once. The accepted process for waste material disposal is to section off a portion of the landfill for the day's fill and to deposit material there, compact throughout the day, and then cover the section at day's end.
To maximize the effective use of landfill space, the waste is compacted. Compaction is usually performed in two stages, prior to and after waste deposit. Compaction prior to delivery at the landfill is usually performed either by the trash collection trucks or at separate compaction or bailing facilities. Generally, household waste, as collected, is between 250-300 lb/yd
3
in density. Collection trucks are able to further compact this waste to 400-700 lb/yd
3
and bailing facilities are capable of compacting waste to levels exceeding 1000 lb/yd
3
in density. Once brought to the landfill facility, waste is deposited into a section of landfill and is further compacted by driving compaction equipment over and about the exposed waste.
Examples of the compaction equipment used for this purpose can range from dedicated compactors, to standard earthmovers and bulldozers. The size, weight, and range of compaction equipment generally corresponds to the size of the landfill installation, with the largest landfills having the most diverse and heaviest equipment. The compaction equipment is used to unload, deposit, and compact waste material to and within the deposit zone with its attached blade or bucket device. Once the initial placement and compaction is performed, the compaction equipment is then driven over the deposited waste material several times throughout the workday, further compacting the deposited fill waste. The fill is compacted, preferably using an area, trench or ramp method, into an open face which is typically inclined at angle of from 5° to 20°.
Studies have shown that 3 to 4 compaction cycles provide the ideal amount of compaction for any given weight of machine and that increasing the number of compaction cycles beyond 4 typically yields little gain in effective compaction. Once placed and compacted within the landfill, the same ordinary household waste that began at 250-300 lb/yd
3
is now stored within the landfill at 600-1500 lb/yd
3
, with the actual amount of compaction depending on the weight and size of the equipment utilized and the number of compactions.
Because waste storage capacity is a landfill's most precious commodity, the traditional soil method of covering the waste has become less and less popular in recent years. In response to the recent demands for more efficient usage of landfill space, alternative daily cover, or ADC, systems have been suggested. The primary goal of an ADC is to perform all the functions of an eight to six inch layer of soil without the drawback of consuming large amounts of landfill capacity. Attempts have been made to cover landfills with removable tarps, but it has been shown that the deployment and retrieval processes are difficult and labor intensive. Nondegradable disposable plastic liners that are designed to be left in place have been proven to take up little landfill space but are considered potentially dangerous because of their tendency to trap methane and other gasses generated by the waste within the layers of the fill.
One ADC that has been widely accepted is the use of a degradable polyolefin film as disclosed in U.S. Pat. Nos. 5,416,133 and 5,565,503 both hereby incorporated herein by reference. The degradable film of polyolefin is desirable as an ADC because it conserves valuable fill capacity and degrades quickly enough (either through chemical, photo, stress, or biodegradation) to reduce the potential for the buildup of gasses between fill layers. An apparatus and a method for deploying degradable film is disclosed in U.S. Pat. No. 5,536,116 (the “116 patent”) and U.S. Pat. No. 5,620,281 hereby incorporated herein by reference.
The apparatus disclosed in the '116 patent includes a film deployment apparatus that may be disposed on the blade of a tractor or other prime mover. The deployment apparatus is attached to the blade, usually by chains, hooks, or both. The tractor is usually powered by a diesel engine while the blade, which may be lifted and lowered, is operated by hydraulic fluid lines and a conventional electrical system. The required hydraulic and electrical power needed to operate the deployment apparatus may be obtained from the tractor by conventional hydraulic and electrical take-off lines. Alternatively, the power, fuel and hydraulic systems may be self contained on the deployment apparatus. After the deployment apparatus is attached to the blade, it may be lifted off the ground by actuating a hydraulic cylinder. When not used to support the deployment apparatus, the blade is used to pu
Johnson Ian
Kozak Randall Jeff
Conley & Rose, P.C.
EPI Environmental Technologies Inc.
Lee Jong-Suk (James)
LandOfFree
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