Landfill

A landfill site (also known as a tip, dump, rubbish dump, garbage dump or dumping ground and historically as a midden[1]) is a site for the disposal of waste materials by burial. It is the oldest form of waste treatment (although the burial part is modern; historically, refuse was just left in piles or thrown into pits). Historically, landfills have been the most common method 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). Unless they are stabilized, these areas may experience severe shaking or soil liquefaction of the ground during a large earthquake.

Wysypisko
A landfill in Poland

Operations

Landfill
One of several landfills used by Dryden, Ontario, Canada.

Typically, operators of well-run landfills for non-hazardous waste meet predefined specifications by applying techniques to:

  1. confine waste to as small an area as possible
  2. compact waste to reduce volume

They can also cover waste (usually daily) with layers of soil or other types of material such as woodchips and fine particles.

During landfill operations, a scale or weighbridge may weigh waste collection vehicles on arrival and personnel may inspect loads 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 can spread and compact the waste on the working face. Before leaving the landfill boundaries, the waste collection vehicles may pass through a wheel-cleaning facility. If necessary, they return to the weighbridge for re-weighing without their load. The weighing process can assemble statistics on the daily incoming waste tonnage, which databases can retain for record keeping. In addition to trucks, some landfills may have equipment 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 include chipped wood or other "green waste",[2] several sprayed-on foam products, chemically "fixed" bio-solids, and temporary blankets. Blankets can be lifted into place at night and 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.

Sanitary Landfill Life Cycle

The term landfill is usually shorthand for a municipal landfill or sanitary landfill. These facilities were first introduced early in the 20th century, but gained wide use in the 1960s and '70s, in an effort to eliminate open dumps and other "unsanitary" waste disposal practices. The sanitary landfill is an engineered facility that separates and confines waste. But that is not all it does. It is actually a biological reactor (bioreactor) in which microbes break down complex organic waste into simpler, less toxic compounds over time. These reactors must be designed and operated according to regulatory standards and guidelines (See environmental engineering).

Usually, aerobic decomposition is the first stage by which wastes are broken down in a landfill. These are followed by four stages of anaerobic degradation. Usually, solid organic material in solid phase decays rapidly as larger organic molecules degrade into smaller molecules. These smaller organic molecules begin to dissolve and move to the liquid phase, followed by hydrolysis of these organic molecules, and the hydrolyzed compounds then undergo transformation and volatilization as carbon dioxide (CO2) and methane (CH4), with rest of the waste remaining in solid and liquid phases.

During the early phases, little material volume reaches the leachate, as the biodegradable organic matter of the waste undergoes a rapid decrease in volume. Meanwhile, the leachate's chemical oxygen demand increases with increasing concentrations of the more recalcitrant compounds compared to the more reactive compounds in the leachate. Successful conversion and stabilization of the waste depends on how well microbial populations function in syntrophy, i.e. an interaction of different populations to provide each other's nutritional needs.[3]:

The life cycle of a municipal landfill undergoes five distinct phases[4][3]:

Phase I - Initial adjustment:

As the waste is placed in the landfill, the void spaces contain high volumes of molecular oxygen (O2). With added and compacted wastes, the O2 content of the landfill bioreactor strata gradually decreases. Microbial populations grow, density increases. Aerobic biodegradation dominates, i.e. the primary electron acceptor is O2.

Phase II - Transition:

The O2 is rapidly degraded by the existing microbial populations. The decreasing O2 leads to less aerobic and more anaerobic conditions in the layers. The primary electron acceptors during transition are nitrates and sulphates, since O2 is rapidly displaced by CO2 in the effluent gas.

Phase III - Acid formation:

Hydrolysis of the biodegradable fraction of the solid waste begins in the acid formation phase, which leads to rapid accumulation of volatile fatty acids (VFAs) in the leachate. The increased organic acid content decreases the leachate pH from approximately 7.5 to 5.6. During this phase, the decomposition intermediate compounds like the VFAs contribute much COD. Long-chain volatile organic acids (VOAs) are converted to acetic acid (C2H4O2), CO2, and hydrogen gas (H2). High concentrations of VFAs increase both the biochemical oxygen demand (BOD) and VOA concentrations, which initiates H2 production by fermentative bacteria, which stimulates the growth of H2-oxidizing bacteria. The H2 generation phase is relatively short because it is complete by the end of the acid formation phase. The increase in the biomass of acidogenic bacteria increases the amount of degradation of the waste material and consuming nutrients. Metals, which are generally more water soluble at lower pH, may become more mobile during this phase, leading to increasing metal concentrations in the leachate.

Phase IV - Methane fermentation:

The acid formation phase intermediary products (e.g. acetic, propionic, and butyric acids) are converted to CH4 and CO2 by methanogenic microorganisms. As VFAs are metabolized by the methanogens, the landfill water pH returns to neutrality. The leachate's organic strength, experessed as oxygen demand, decreases at a rapid rate with increases in CH4 and CO2 gas production. This is the longest decomposition phase.

Phase V - Final maturation and stabilization:

The rate of microbiological activity slows during the last phase of waste decomposition as the supply of nutrients limits the chemical reactions, e.g. as bioavailable phosphorus becomes increasingly scarce. CH4 production almost completely disappears, with O2 and oxidized species gradually reappearing in the gas wells as O2 permeates downwardly from the troposphere. This transforms the oxidation–reduction potential (ORP) in the leachate toward oxidative processes. The residual organic materials may incrementally be converted to the gas phase, and as organic matter is composted; i.e. the organic matter is converted to humic-like compounds.

Social and environmental impact

Landfill Hawaii
Landfill operation in Hawaii. Note that the area being filled is a single, well-defined "cell" and that a protective landfill liner is in place (exposed on the left) to prevent contamination by leachates migrating downward through the underlying geological formation.

Landfills have the potential to cause a number of issues. Infrastructure disruption, such as damage to access roads by heavy vehicles, may occur. Pollution of local roads and water courses from wheels on vehicles when they leave the landfill can be significant and can be mitigated by wheel washing systems. Pollution of the local environment, such as contamination of groundwater or aquifers or soil contamination may occur, as well.

Leachate

In some places, efforts are made to capture and treat leachate from landfills before it reaches groundwater aquifers. However, liners always have a lifespan, though it may be 100 years or more. Eventually, every landfill liner will leak,[5] allowing pollutants to contaminate groundwater.

Decomposition gases

Rotting food and other decaying organic waste creates decomposition gases, especially CO2 and CH4 from aerobic and anaerobic decomposition, respectively. Both processes occur simultaneously in different parts of a landfill. In addition to available O2, the fraction of gas constituents will vary, depending on the age of landfill, type of waste, moisture content and other factors. For example, the maximum amount of landfill gas produced can be illustrated a simplified net reaction of diethyl oxalate that accounts for these simultaneous reactions [6]:

C6H10O4 + 1:5H2O → 3:25CH4 + 2:75CO2

On average, about half of the volumetric concentration of landfill gas is CH4 and slightly less than half is CO2. The gas also contains about 5% molecular nitrogen (N2), less than 1% hydrogen sulfide (H2S), and a low concentration of non-methane organic compounds (NMOC), about 2700 ppmv[7]

Landfill gases can seep out of the landfill and into the surrounding air and soil. Methane is a greenhouse gas, and is flammable and potentially explosive at certain concentrations, which makes it perfect for burning to generate electricity cleanly. Since decomposing plant matter and food waste only release carbon that has been captured from the atmosphere through photosynthesis, no new carbon enters the carbon cycle and the atmospheric concentration of CO2 is not affected. Carbon dioxide traps heat in the atmosphere, contributing to climate change.[8] In properly managed landfills, gas is collected and flared or recovered for landfill gas utilization.

Vectors

Poorly run landfills may become nuisances because of vectors such as rats and flies which can spread infectious diseases. The occurrence of such vectors can be mitigated through the use of daily cover.

Other nuisances

Other potential issues include wildlife disruption, dust, odor, noise pollution, and reduced local property values.

Landfill gas

Gases are produced in landfills due to the anaerobic digestion by microbes. In a properly managed landfill this gas is collected and used. Its uses range from simple flaring to the landfill gas utilization and generation of electricity. Landfill gas monitoring alerts workers to the presence of a build-up of gases to a harmful level. In some countries, landfill gas recovery is extensive; in the United States, for example, more than 850 landfills have active landfill gas recovery systems.[9]

Regional practice

Landfill face
A landfill in Perth, Western Australia
South East New Territories Landfill 2
South East New Territories Landfill, Hong Kong

Canada

Landfills in Canada are regulated by provincial environmental agencies and environmental protection legislation.[10] Older facilities tend to fall under current standards and are monitored for leaching.[11] Some former locations have been converted to parkland.

European Union

Deponieverbote
Landfill bans in Europe

In the European Union, individual states are obliged to enact legislation to comply with the requirements and obligations of the European Landfill Directive. In the UK this is the Waste Implementation Programme.

Finland, Sweden, Denmark, Poland, Germany, the Netherlands, Belgium, Austria and Slovenia have laws banning or severely restricting the disposal of household trash via landfills. [12]

United Kingdom

Landfilling practices in the UK have had to change in recent years to meet the challenges of the European Landfill Directive. The UK now imposes landfill tax upon biodegradable waste which is put into landfills. In addition to this the Landfill Allowance Trading Scheme has been established for local authorities to trade landfill quotas in England. A different system operates in Wales where authorities are not able to 'trade' between themselves, but have allowances known as the Landfill Allowance Scheme.

United States

U.S. landfills are regulated by each state's environmental agency, which establishes minimum guidelines; however, none of these standards may fall below those set by the United States Environmental Protection Agency (EPA).[13]

Permitting a landfill generally takes between five and seven years, costs millions of dollars and requires rigorous siting, engineering and environmental studies and demonstrations to ensure local environmental and safety concerns are satisfied.[14]

Types

Microbial topics

The status of a landfill's microbial community may determine its digestive efficiency.[17]

Bacteria that digest plastic have been found in landfills.[18]

Reclaiming materials

Landfills can be regarded as a viable and abundant source of materials and energy. In the developing world, waste pickers often scavenge for still-usable materials. In a commercial context, landfill sites have also been discovered by companies, and many have begun harvesting materials and energy .[19] Well known examples are gas recovery facilities.[20] 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.).

Alternatives

In addition to waste reduction and recycling strategies, there are various alternatives to landfills, including waste-to-energy incineration, anaerobic digestion, composting, mechanical biological treatment, pyrolysis and plasma arc gasification. Depending on local economics and incentives, these can be made more financially attractive than landfills.

Restrictions

Deponieverbote
European countries that have banned the disposal of untreated waste in landfills

Countries including Germany, Austria, Sweden,[21] Denmark, Belgium, the Netherlands, and Switzerland, have banned the disposal of untreated waste in landfills. In these countries, only certain hazardous wastes, fly ashes from incineration or the stabilized output of mechanical biological treatment plants may still be deposited.

See also

References

  1. ^ "Midden". Merriam-Webster. Retrieved May 18, 2014.
  2. ^ "Alternative Daily Cover (ADC)". Retrieved September 14, 2012.
  3. ^ a b Letcher, T.M.; Vallero, D.A., eds. (2019). ”Municipal Landfill, D. Vallero and G. Blight, pp. 235-249 in Waste: A Handbook for Management. Amsterdam, Netherlands and Boston MA, Print Book: Elsevier Academic Press. ISBN 9780128150603. 804 pages.
  4. ^ U.S. Environmental Protection Agency (2007) Landfill bioreactor performance: second interim report: outer loop recycling & disposal facility - Louisville, Kentucky, EPA/600/R-07/060
  5. ^ US EPA, "Solid Waste Disposal Facility Criteria; Proposed Rule", Federal Register 53(168):33314–33422, 40 CFR Parts 257 and 258, US EPA, Washington, D.C., August 30 (1988a).
  6. ^ Themelis, Nickolas J., and Priscilla A. Ulloa. "Methane generation in landfills." Renewable Energy 32.7 (2007), 1243-1257
  7. ^ Themelis, Nickolas J., and Priscilla A. Ulloa. "Methane generation in landfills." Renewable Energy 32.7 (2007), 1243-1257
  8. ^ "CO2 101: Why is carbon dioxide bad?". Mother Nature Network. Retrieved November 30, 2016.
  9. ^ Powell, Jon T.; Townsend, Timothy G.; Zimmerman, Julie B. (September 21, 2015). "Estimates of solid waste disposal rates and reduction targets for landfill gas emissions". Nature Climate Change. 6: 162–165. doi:10.1038/nclimate2804.
  10. ^ Landfill Inventory Management Ontario - How Ontario regulates Landfills - Ministry of the Environment
  11. ^ Aging Landfills: Ontario's Forgotten Polluters - Eco Issues
  12. ^ http://www.cewep.eu/media/cewep.eu/org/med_557/1406_2015-02-03_cewep_-_landfill_inctaxesbans.pdf
  13. ^ Horinko, Marianne, Cathryn Courtin. “Waste Management: A Half Century of Progress.” EPA Alumni Association. March 2016.
  14. ^ "Modern landfills". Archived from the original on February 22, 2015. Retrieved February 21, 2015.
  15. ^ EPA, OSWER, ORCR, US. "Basic Information about Landfills". www.epa.gov. Retrieved March 14, 2017.CS1 maint: Multiple names: authors list (link)
  16. ^ "Disposal and Storage of Polychlorinated Biphenyl (PCB) Waste". United States Environmental Protection Agency. Retrieved May 10, 2017.
  17. ^ Gomez, A.M.; =Yannarell, A.C.; Sims, G.K.; Cadavid-Resterpoa, G.; Herrera, C.X.M. (2011). "Characterization of bacterial diversity at different depths in the Moravia Hill Landfill site at Medellín, Colombia". Soil Biology and Biochemistry. 43 (6): 1275–1284. doi:10.1016/j.soilbio.2011.02.018.
  18. ^ Gwyneth Dickey Zaikab (March 2011). "Marine microbes digest plastic".
  19. ^ Multiple Purpose industries using landfills for energy Archived December 8, 2009, at the Wayback Machine[Positional parameters ignored]=
  20. ^ Commercial exploitation of gas from landfills
  21. ^ "Regeringskansliets rättsdatabaser". rkrattsbaser.gov.se (in Swedish). Retrieved May 9, 2019.

Further reading

External links

Atari video game burial

The Atari video game burial was a mass burial of unsold video game cartridges, consoles, and computers in a New Mexico landfill site, undertaken by American video game and home computer company Atari, Inc. in 1983. Up until 2014, the goods buried were rumored to be unsold copies of E.T. the Extra-Terrestrial, one of the biggest commercial failures in video gaming and often cited as one of, if not, the worst video game ever released, along with the Atari 2600 port of Pac-Man, which was commercially successful but critically maligned.

Since the burial was first reported in the press, there had been doubts as to its veracity and scope, leading to it being frequently dismissed as an urban legend. In either case the event had become a cultural icon and a reminder of the North American video game crash of 1983; it was the end result of a disastrous fiscal year which saw Atari, Inc. sold off by its parent company Warner Communications. Though it was believed that millions of copies of E.T. were disposed of in the landfill, Atari officials later verified the numbers to be around 700,000 cartridges of various titles, including E.T.

In 2014, Fuel Industries, Microsoft, and others worked with the New Mexico government to excavate the site to validate the contents of the landfill as part of a documentary called Atari: Game Over. On April 26, 2014, the excavation revealed discarded games and hardware. Only a small fraction, about 1,300 cartridges, were recovered during the excavation period, with a portion given for curation and the rest auctioned to raise money for a museum to commemorate the burial.

Biogas

Biogas is the mixture of gases produced by the breakdown of organic matter in the absence of oxygen. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste. Biogas is a renewable energy source.

Biogas is produced by anaerobic digestion with methanogen or anaerobic organisms, which digest material inside a closed system, or fermentation of biodegradable materials. This closed system is called an anaerobic digester, biodigester or a bioreactor.Biogas is primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulfide (H2S), moisture and siloxanes. The gases methane, hydrogen, and carbon monoxide (CO) can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used for any heating purpose, such as cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat.Biogas can be compressed, the same way as natural gas is compressed to CNG, and used to power motor vehicles. In the United Kingdom, for example, biogas is estimated to have the potential to replace around 17% of vehicle fuel. It qualifies for renewable energy subsidies in some parts of the world. Biogas can be cleaned and upgraded to natural gas standards, when it becomes bio-methane. Biogas is considered to be a renewable resource because its production-and-use cycle is continuous, and it generates no net carbon dioxide. As the organic material grows, it is converted and used. It then regrows in a continually repeating cycle. From a carbon perspective, as much carbon dioxide is absorbed from the atmosphere in the growth of the primary bio-resource as is released, when the material is ultimately converted to energy.

Edgemere Landfill

Edgemere Landfill is a former municipal landfill located in Edgemere on the Rockaway peninsula in Queens, New York City. It is located on a man-made peninsula on the Jamaica Bay shoreline, at the eastern end of the Rockaway peninsula. A portion of the site is currently open to the public as Rockaway Community Park (formerly Edgemere Park). The entire site is owned by the New York City Department of Parks and Recreation.

The landfill began operations in June 1938, merging several islands in the Jamaica Bay marshland and connecting them to the main Rockaway Peninsula. Shortly afterward, a portion of the site was used as the Rockaway Airport. Edgemere Park was conceived for the landfill site in the 1950s by New York City Parks Commissioner Robert Moses, as part of the infrastructure for the adjacent Edgemere Houses housing project. The site, along with several other planned parks in the city, continued operations as a landfill in order to fill the marshland for park development. The small portion of Rockaway Community Park adjacent to the Edgemere Houses was developed in the 1960s. During its operation, the landfill was a dumping site for toxic chemicals and waste oil, and served as a hazard to nearby John F. Kennedy International Airport by attracting birds. Following the discovery of toxic waste drums in the landfill in 1983, the landfill was declared a Superfund site. It was closed in 1991 and capped afterwards.

The peak of the landfill is the tallest point in the Rockaways, measuring 70 feet (21 m) high. The landfill is claimed to be "the longest continuously operating dump in the United States", accepting waste from 1938 to 1991. It is also one of the oldest landfills in New York City, and was the second-to-last city landfill to remain in operation. The final landfill, Fresh Kills Landfill in Staten Island, closed in 2001.

Environmental remediation

Environmental remediation deals with the removal of pollution or contaminants from environmental media such as soil, groundwater, sediment, or surface water. This would mean that once requested by the government or a land remediation authority, immediate action should be taken as this can impact negatively on human health and the environment.

Remedial action is generally subject to an array of regulatory requirements, and also can be based on assessments of human health and ecological risks where no legislated standards exist or where standards are advisory.

To help with environmental remediation, one can get environmental remediation services. These services help eliminate radiation sources in order to help protect the environment.

Fresh Kills Landfill

The Fresh Kills Landfill was a landfill covering 2,200 acres (890 ha) in the New York City borough of Staten Island in the United States. The name comes from the landfill's location along the banks of the Fresh Kills estuary in western Staten Island.The landfill was opened in 1948 as a temporary landfill but by 1955 it became the largest landfill in the world and it remained so until its closure in 2001. At the peak of its operation, in 1986, Fresh Kills received 29,000 tons of residential waste per day. From 1991 until its closing it was the only landfill to receive New York City's residential waste. It consists of four mounds which range in height from 90 to approximately 225 feet and hold approximately 150 million tons of solid waste. The archaeologist Martin Jones characterises it as "among the largest man-made structures in the history of the world."In October 2008, reclamation of the site began for a multi-phase, 30-year site redevelopment. The landfill is eventually expected to be developed as Freshkills Park.

Freshkills Park

Freshkills Park is a public park being built atop a landfill reclamation project on Staten Island. At about 2,200 acres (8.9 km2), it will be the largest park developed in New York City since the 19th century. Its construction began in October 2008 and is slated to continue in phases for at least 30 years. When fully developed by 2035-37, Freshkills Park will be the second-largest park in New York City and almost three times the size of Central Park in Manhattan. The park has been designed for five major sections that accommodate a range of uses, including cultural, athletic, and educational programs. Sections of the park will be connected by a circulation system for vehicles and a network of paths for bicyclists, pedestrians, and equestrians. The New York City Department of Parks and Recreation (NYC Parks) is running the project with the New York City Department of Sanitation.

Indie rock

Indie rock is a genre of rock music that originated in the United States and United Kingdom in the 1970s. Originally used to describe independent record labels, the term became associated with the music they produced and was initially used interchangeably with alternative rock. As grunge and punk revival bands in the US and Britpop bands in the UK broke into the mainstream in the 1990s, it came to be used to identify those acts that retained an outsider and underground perspective. In the 2000s, as a result of changes in the music industry and the growing importance of the Internet, some indie rock acts began to enjoy commercial success, leading to questions about its meaningfulness as a term.

Sometimes used interchangeably with "guitar pop rock", in the mid-1980s, the term "indie" (or "indie pop") began to be used to describe the music produced on punk and post-punk labels. Some prominent indie rock record labels were founded during the 1980s. During the 1990s, grunge bands broke into the mainstream, and the term "alternative" lost its original counter-cultural meaning. The term "indie rock" became associated with the bands and genres that remained dedicated to their independent status. By the end of the 1990s, indie rock developed several subgenres and related styles, including lo-fi, noise pop, emo, slowcore, post-rock, and math rock. In the 2000s, changes in the music industry and in music technology enabled a new wave of indie rock bands to achieve mainstream success.In the early 2000s, a new group of bands that played a stripped-down, back-to-basics version of guitar rock emerged into the mainstream. The commercial breakthrough from these scenes was led by four bands: The Strokes, The White Stripes, The Hives and The Vines. Emo also broke into mainstream culture in the early 2000s. By the end of the decade, the proliferation of indie bands was being referred to as "indie landfill".

Land reclamation

Land reclamation, usually known as reclamation, and also known as land fill (not to be confused with a landfill), is the process of creating new land from oceans, riverbeds, or lake beds. The land reclaimed is known as reclamation ground or land fill.

In a number of other jurisdictions, including parts of the United States, the term "reclamation" can refer to returning disturbed lands to an improved state. In Alberta, Canada, for example, reclamation is defined by the provincial government as "The process of reconverting disturbed land to its former or other productive uses." In Oceania it is frequently referred to as land rehabilitation.

Landfill Directive

The Landfill Directive, more formally Council Directive 1999/31/EC of 26 April 1999 is a European Union directive that regulates waste management of landfills in the European Union. It was implemented by its Member States by 16 July 2001.

The Directive's overall aim is "to prevent or reduce as far as possible negative effects on the environment, in particular the pollution of surface water, groundwater, soil and air, and on the global environment, including the greenhouse effect, as well as any resulting risk to human health, from the landfilling of waste, during the whole life-cycle of the landfill". This legislation also has important implications for waste handling and waste disposal.

Landfill fire

A landfill fire occurs when waste disposed of in a landfill ignites and spreads. Two types of landfills fires are generally recognized. Surface Fires and Deep Seated Fires. Surface fires typically occur in underdeveloped countries that lack capacity to properly cover waste with inert daily and intermediate cover. Modern examples of such fires include the Deonar and Ghazipur Landfills in India, Cerro Patacon Landfill in Panama and the New Providence Landfill in the Bahamas.

In landfills that do not cover their waste with daily cover, air intrusion provides the oxygen required for increased biological activity decomposition that creates substantial heat and can cause material in the landfills to spontaneously combust.. If unchecked, spontaneous combustion fires in particular tend to burn deeper into the waste mass, resulting in deep seated fires. In the U.S. 40% of landfill fires are attributed to arson.Landfill fires are especially dangerous as they can emit dangerous fumes from the combustion of the wide range of materials contained within the landfill. Key parameters of concern are carbon monoxide, hydrogen sulphide, volatile organics. Production of dioxins and furans is also a documented risk factor.

Subsurface landfill fires also, unlike a typical fire, are difficult to put out with water unless an overhaul operation is undertaken. They are similar to coal seam fires and peat fires. Oxygen intrusion control is the best method to prevent and fight subsurface landfill fires as long as the fire fighting team can be confident that all air entry pathways are effectively blocked. "Fuel quenching", by allowing landfill gas build-up, can work well, especially in conjunction with maintenance of the daily cover of soil or material places on landfills. However, this oxygen suppression method can be compromised if cracks develop in the soil cover due to settlement.

Nearby streams can be threatened by leachate pools which may form if water is used to extinguish fires in landfills. for this reason, recirculation of fire fighting water should be considered to minimize environmental impacts. There is also the danger that the landfill's membrane, a barrier placed under most modern landfills to prevent contamination of the underlying ground, will be destroyed or penetrated by the fire itself. Normally this liner prevents harmful liquids contained within the landfill from escaping into the groundwater and nearby streams. Destruction of the liner therefore leads to serious environmental problems.

Landfill gas

Landfill gas is a complex mix of different gases created by the action of microorganisms within a landfill. Landfill gas is approximately forty to sixty percent methane, with the remainder being mostly carbon dioxide. Trace amounts of other volatile organic compounds (VOCs) comprise the remainder (<1%). These trace gases include a large array of species, mainly simple hydrocarbons.Landfill gases have an influence on climate change. The major components are CO2 and methane, both of which are greenhouse gas. Methane in the atmosphere is a far more potent greenhouse gas, with each molecule having twenty five times the effect of a molecule of carbon dioxide. Methane itself however accounts for less composition of the atmosphere than does carbon dioxide. Landfills are the third largest source of methane in the US.

Landfill mining

Landfill mining and reclamation (LFMR) is a process whereby solid wastes

which have previously been landfilled are excavated and processed. The function of landfill mining is to reduce the amount of landfill mass encapsulated within the closed landfill and/or temporarily remove hazardous material to allow protective measures to be taken before the landfill mass is replaced. In the process, mining recovers valuable recyclable materials, a combustible fraction, soil, and landfill space. The aeration of the landfill soil is a secondary benefit regarding the landfill's future use. The combustible fraction is useful for the generation of power. The overall appearance of the landfill mining procedure is a sequence of processing machines laid out in a functional conveyor system. The operating principle is to excavate, sieve and sort the landfill material.

The concept of mining was introduced as early as 1953 at the Hiriya landfill operated by the Dan Region Authority next to the city of Tel Aviv, Israel. Waste contains many resources with high value, the most notable of which are non-ferrous metals such as aluminium cans and scrap metal. The concentration of aluminium in many landfills is higher than the concentration of aluminum in bauxite from which the metal is derived.

Leachate

A leachate is any liquid that, in the course of passing through matter, extracts soluble or suspended solids, or any other component of the material through which it has passed.

Leachate is a widely used term in the environmental sciences where it has the specific meaning of a liquid that has dissolved or entrained environmentally harmful substances that may then enter the environment. It is most commonly used in the context of land-filling of putrescible or industrial waste.

In the narrow environmental context leachate is therefore any liquid material that drains from land or stockpiled material and contains significantly elevated concentrations of undesirable material derived from the material that it has passed through.

Oyster Point Marina/Park

Oyster Point Marina/Park is a 408-berth public marina and 33-acre (13 ha) park located in the city of South San Francisco, California on the western shoreline of San Francisco Bay.The City of South San Francisco owns Oyster Point Marina/Park. The San Mateo County Harbor District has operated Oyster Point Marina/Park under a Joint Powers Agreement (JPA) with the City since 1977. The JPA terminates in 2026.

The marina is located close to nearby job centers in various office complexes and high rises in downtown of this city known as a regional biotech center. It includes a fuel dock, boat launching ramp, and fishing pier. In addition to boating and parkland, there are hiking and jogging trails, picnic areas, and 2.5 acres (1.0 ha) of sandy beaches.

Pulau Semakau

Pulau Semakau (or Semakau Island) is located to the south of the main island of Singapore, off the Straits of Singapore. The Semakau Landfill is located on the eastern side of the island, and was created by the amalgamation of Pulau Sakeng (also known as Pulau Seking), and "anchored" to Pulau Semakau. The Semakau Landfill is Singapore's first offshore landfill and now the only remaining landfill in Singapore.

Toxic waste

Toxic waste is any unwanted material in all forms that can cause harm (e.g. by being inhaled, swallowed, or absorbed through the skin). Many of today's household products such as televisions, computers and phones contain toxic chemicals that can pollute the air and contaminate soil and water. Disposing of such waste is a major public health issue.

Waste collection

Waste collection is a part of the process of waste management. It is the transfer of solid waste from the point of use and disposal to the point of treatment or landfill. Waste collection also includes the curbside collection of recyclable materials that technically are not waste, as part of a municipal landfill diversion program.

Waste in New Zealand

The management of waste in New Zealand has become more regulated to reduce associated environmental issues.

Waste management in Hong Kong

In the densely populated Hong Kong, waste is a complex issue. The territory generates around 6.4 million tons of waste each year but is able to collect and process only a minimal portion of recyclable waste. By 2019, its existing landfills are expected to be full. The government has introduced waste management schemes and is working to educate the public on the subject. On the commercial side, producers are taking up measures to reduce waste.

Major types
Processes
Countries
Agreements
Other topics

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