LFG (Land Fill Gas) is a source of methane. This blog repeatedly has made note of projects, where the gaseous byproduct from the biological decomposition of organic material in the absence of oxygen is upgraded and used for power generation. Less often has this blog noted the use of CNG (Compressed Natural Gas) as a transportation fuel, with a portion of the methane coming from renewable energy sources rather than drilling. Given present and anticipated world conditions, it is worthwhile to consider both applications.
“Upgrading on digestion gas has been practiced since 1935 and, in Germany, there was large scale injection into the gas grid between 1982 and 1999. Since 1992 there has also been injection into the gas grid in Sweden, Switzerland and the Netherlands. Injection currently only occurs in local distribution gas grids, though. In these cases, relatively small volumes are added, at low pressures, mostly for domestic end-users. As far as is known, no major problems have been reported related to the addition of biogas to natural gas.”
Such a source of renewable energy has been developed more in Europe than Asia or the Americas. Development has begun to move forward elsewhere. This blog previously noted establishment of biogas recovery, refining, transportation and supply systems in Japan. Recently noted was methane extraction from landfills in Brazil. And, also noted in the United States was co-digestion to produce biogas, followed by conditioning and storage of the bio-methane by Environmental Power Corporation.
Green Car Congress now reports on a joint venture between Linde North America and Waste Management. They plan to build the world’s largest facility for processing landfill gas (LFG) into liquefied natural gas (LNG). The facility will be situated at the Altamont Landfill near Livermore, California. The developers anticipate that operation will begin in 2009.
The projected production capacity is up to 13,000 gallons per day of LNG. The report mentions that plant capacity would be sufficient to fuel 300 refuse trucks, so this may be another instance of converting LFG to be used as an alternative transportation fuel.
(Serendipity again, GCC, I just finished suggesting the need to test heavy-duty, short haul transport that utilizes Big Electric serial hybrid propulsion with generator sets running on a combination of Natural Gas and biogas.)
Biogas and landfill gas are somewhat different. Biogas is a product of anaerobic digestion of animal manure; sometimes referred to as cow power or poop power. When the waste is offal, it may be referred to as “digester gas”. Organic material entering land fill is more heterogeneous.
Gas cleaning is necessary to eliminate impurities in the biogas produced at waste treatment facilities. These impurities are principally hydrogen sulfide, halogens (fluorine, chlorine and bromine), moisture, bacteria and solids. LFG can have heavy hydrocarbons (both aliphatic and aromatics such as benzene), chlorinated hydrocarbons (e.g., dioxin, furans, and PCBs (Poly Chlorinated Bi-phenyls).
LFG requires more extensive cleaning and careful monitoring for toxins.
Linde will use a multi-step purification system to remove CO2, N2, H2S and trace contaminants and then use a cryogenic process to cool the purified gas into LNG at a temperature of -260° F.
Currently, Waste Management has 10 waste treatment landfill projects in operation in the US and Canada that have full-scale bio-reactors.
A bioreactor landfill operates to rapidly transform and degrade organic waste through the addition of liquid and air to enhance microbial processes. These bioreactors can be used for the production of landfill gas. There are three different general types of bioreactor landfill configurations, according to the EPA:
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Aerobic. In an aerobic bioreactor landfill, leachate is removed from the bottom layer, piped to liquids storage tanks, and re-circulated into the landfill in a controlled manner. Air is injected into the waste mass, using vertical or horizontal wells, to promote aerobic activity and accelerate waste stabilization.
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Anaerobic. In an anaerobic bioreactor landfill, moisture is added to the waste mass in the form of re-circulated leachate and other sources to obtain optimal moisture levels. Biodegradation occurs in the absence of oxygen (anaerobically) and produces landfill gas. Landfill gas, primarily methane, can be captured to minimize greenhouse gas emissions and for energy projects.
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Hybrid (Aerobic-Anaerobic). The hybrid bioreactor landfill accelerates waste degradation by employing a sequential aerobic-anaerobic treatment to rapidly degrade organics in the upper sections of the landfill and collect gas from lower sections. Operation as a hybrid results in the earlier onset of methanogenesis compared to aerobic landfills.
BIOGASMAX is a project in Europe that uses urban waste as feedstock with garbage trucks and city buses partially running on methane extracted from anaerobic digestion.
In addition to gaining the operational knowledge needed for working with anaerobic and hybrid bioreactor technologies, Waste Management currently is evaluating the economic and environmental impacts. Such knowledge is wanted by a number of governmental, non-governmental and commercial entities. For instance, “the $15.5 million Waste Management-Linde project will receive grant assistance from the California Integrated Waste Management Board, the California Air Resources Board, and the South Coast Air Quality Management District.” This blog previously mentioned biogas projects at urban waste treatment facilities in California that receive similar support.
GCC Recommended Resources
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Bioreactors (EPA)
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While bio-char may bite, says the amazingdrx, but “bio-gas (from manure, garbage, and biomass waste) still offsets 20 times the effective GHG that it emits when burned.”
“Many Americans,” writes Wes Muir, Director of Communications for Waste Management, Inc, “are increasingly turning to alternative forms of energy, and one exciting source that has seen recent resurgence in use is landfill gas.”
Image credit::Parnell Biogas Landfill Gas Flaring Systems
Philadelphia Treehugger John Laumer cites the prospects that Muir sees for the USA, i.e. a 2,500 megawatt opportunity converting landfill gas to energy. Waste Management (WM) has over 100 sites that have landfill gas to energy (LFGTE) facilities and the company plans to build another 60 plants by 2012. One that now is under construction is near Livermore, Calif.
Using the methane created at landfills rather than allowing it to escape into the atmosphere is a way to curb anthropogenic emissions that cause global heating besides providing a source of energy. Waste Management is focussed upon collection of the methane and using it to fuel onsite engines or turbines that generate electricity to power surrounding homes and neighborhoods. When fossil fuels are burned at utility power plants to generate electricity, LFGTE technology further reduces greenhouse gases.
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[...] course, if we produce enough, someone may decide to start turning it into LNG and shipping it offshore, so this wouldn’t necessarily be a [...]
[...] before a usable product can be added to the gas line, significant upgrading must occur. And, logistics is not the only approach that must be considered. Since manure to biogas [...]