Landfills

landfill landfill site (also known as tip, dump, rubbish dump or dumping ground and historically as amidden) is a site for the disposal of waste materials by burial and is the oldest form of waste treatment. Historically, landfills have been the most common methods of organized waste disposal and remain so in many places around the world. Some landfills are also used for waste management purposes, such as the temporary storage, consolidation and transfer, or processing of waste material (sorting, treatment, or recycling).
A landfill also may refer to ground that has been filled in with rocks instead of waste materials, so that it can be used for a specific purpose, such as for building houses. Unless they are stabilized, these areas may experience severe shaking or liquefaction of the ground in a large earthquake.

operations
Typically, in non hazardous waste landfills, in order to meet predefined specifications, techniques are applied by which the wastes are: 1. Confined to as small an area as possible. 2. Compacted to reduce their volume. 3. Covered (usually daily) with layers of soil.
During landfill operations the waste collection vehicles are weighed at a weighbridge on arrival and their load is inspected for wastes that do not accord with the landfill’s waste acceptance criteria. Afterward, the waste collection vehicles use the existing road network on their way to the tipping face or working front where they unload their contents. After loads are deposited,compactors or bulldozers are used to spread and compact the waste on the working face. Before leaving the landfill boundaries, the waste collection vehicles pass through a wheel cleaning facility. If necessary, they return to the weighbridge in order to be weighed without their load. Through the weighing process, the daily incoming waste tonnage can be calculated and listed in databases for record keeping. In addition to trucks, some landfills may be equipped to handle railroad containers. The use of 'rail-haul' permits landfills to be located at more remote sites, without the problems associated with many truck trips.
Typically, in the working face, the compacted waste is covered with soil or alternative materials daily. Alternative waste-cover materials are chipped wood or other "green waste",[1] several sprayed-on foam products, chemically 'fixed' bio-solids and temporary blankets. Blankets can be lifted into place at night then removed the following day prior to waste placement. The space that is occupied daily by the compacted waste and the cover material is called a daily cell. Waste compaction is critical to extending the life of the landfill. Factors such as waste compressibility, waste layer thickness and the number of passes of the compactor over the waste affect the waste densities. impacts A large number of adverse impacts may occur from landfill operations. Damage occurrence can includeinfrastructure (e.g. damage to access roads by heavy vehicles); pollution of the local environment(such as contamination of groundwater and/oraquifers by leakage or sinkholes[2] and residual soil contamination during landfill usage, as well as after landfill closure); off gassing of methane generated by decaying organic wastes (methane is agreenhouse gas many times more potent than carbon dioxide, and can itself be a danger to inhabitants of an area); harboring of disease vectorssuch as rats and flies, particularly from improperly operated landfills, which are common in developing countries; injuries to wildlife; and simple nuisance problems (e.g., dust, odor, vermin, or noise pollution). This list is growing steadily as time passes.
Some local authorities have found it difficult to locate new landfills. Communities may charge a fee or levy in order to discourage waste and/or recover the costs of site operations. Many landfills are publicly funded, but some are commercial businesses, operated for profit.

problems
One of the problems of landfills is pollution of the road from dirty wheels on vehicles when they leave the landfill. To reduce this, wheel washing systems are used to clean the wheels as the vehicle exits the landfill. Poisonous lechate can also leak from the landfill contaminating nearby soil and groundwater. Methane gases are flammable and explosive if exposed to heat.

reclaiming
Landfills can be regarded as a viable and abundant source of materials and energy. In the developing world, this is widely understood and one may thus often find waste pickers scavenging for still usable materials. In a commercial context, landfills sites have also been discovered by companies and many have begun harvesting materials and energy .[10] Well known examples are gas recovery facilities.[11] Other commercial facilities include waste incinerators which have built-in material recovery. This material recovery is possible through the use of filters (electro filter, active carbon and potassium filter, quench, HCL-washer, SO2-washer, bottom ash-grating, etc.). An example of these is the AEB Waste Fired Power Plant.[12][13] The AEB waste incinerator is hereby able to recover a large part of the burned waste in source materials. According to Marcel van Berlo (who helped build the plant), the processed waste contained higher percentages of source materials than any mine in the world. He also added that when the plant was compared to a Chilean copper mine, the waste fired plant could recover more copper.[14] However, because of the high concentration of gases and the unpredictability of the landfill contents, which often include sharp objects, landfill excavation is generally considered dangerous. Furthermore, the quality of materials residing within landfills tends to degrade and such materials are thought to be not worth the risks required to recover them.

alternatives
The alternatives to landfills are waste reduction and recycling strategies. Secondary to not creating waste, there are various alternatives to landfills. In the late 20th century, alternative methods of waste disposal to landfill and incineration have begun to gain acceptance. Anaerobic digestion,composting, mechanical biological treatment, pyrolysis and plasma arc gasification have all begun to establish themselves in the market.
In recent years, some countries, such as Germany, Austria, Belgium, the Netherlands, andSwitzerland, have banned the disposal of untreated waste in landfills. In these countries, only the ashes from incineration or the stabilized output of mechanical biological treatment plants may still be deposited.