Environmental Biodegradable Additive
Landfill Gas
632 of LFG ( landfill gas ) energy projects are currently operate in the United States, in March 2018*. Projects involve public and private organizations, small and large landfills, and various types of technology. Read about successful LFG energy projects that are enjoying the environmental and economic benefits of using LFG.
Landfill gas has been shown to create a carbon negative change in the environment ( prevent green house gas, and methane emission to atmosphere ) when items that in landfills biodegrade. The EPA ( Environmental Protection Agency in USA ) has released information that assures citizens that 69% of methane created in landfills is captured or flared off. Once the methane is captured 90% is converted into energy and 10% is oxidized releasing 0% methane into the atmosphere.
The EPA-USA has funded the landfill methane outreach program, which is sharing with landfill operators and owners the benefits of capturing the methane gas. The outcome of capturing methane gas ? Carbon negative, EBA Additive allows plastics which utilize the technology to be carbon negative 35% of the time. Once the methane is captured 100% is converted, green house gas ( GHG ) emissions is negative.
* Reference :
United States Environmental protection Agency
Natural Resources Convention Service
Landfill Gas Utilization in Hong Kong
Landfill Gas in Hong Kong
The Landfill Gas Utilization Project is now operating at NENT Landfill site in Hong Kong, since 25th January 2008. The landfill gas generated is now captured and transmit the surplus LFG to Town Gas plant in Tai Po Industrial Estate, as an alternative heating fuel for town gas production. LFG in other landfill in Hong Kong is also captured fro generating electricity to meet on site electricity demands. However, as the volume of LFG is expected to increase, the surplus LFG should be utilized as power / electricity supplies for the benefit to local society.
* Reference :
Landfill Gas Utilization in Hong Kong
Landfill Gas Output in Hong Kong
A new Landfill Gas Utilization Project by CLP is now just operating at WENT Landfill in Hong Kong starting at the end of 2018. The project’s first phase comprises five units capable generating enough electricity to power 17,000 four-person households for one year. A second phase will add two more units in power supply.
Reference :
CLP Power to tap methane from Landfill for Electricity Supply
Landfill Gas Power Generation Project at WENT Landfill
What is landfill gas composed of in nowadays ?
Landfill gas is composed of a mixture of hundreds of different gases. By volume, landfill gas typically contains 45% to 60% methane and 40% to 60% carbon dioxide. Landfill gas also includes small amounts of nitrogen, oxygen, ammonia, sulfides, hydrogen, carbon monoxide, and non-methane organic compounds (NMOCs) such as trichloroethylene, benzene, and vinyl chloride.
How is landfill gas produced?
Three processes—bacterial decomposition, volatilization, and chemical reactions—form landfill gases. Bacterial decomposition. Most landfill gas is produced by bacterial decomposition, which occurs when organic waste is broken down by bacteria naturally present in the waste and in the soil used to cover the landfill. Organic wastes include food, garden waste, street sweepings, textiles, wood and paper products. Bacteria decompose organic waste in four phases, and the composition of the gas changes during each phase.
The Four Phases of Bacterial Decomposition of Landfill Waste
Bacteria decompose landfill waste in four phases. The composition of the gas produced changes with each of the four phases of decomposition. Landfills often accept waste over a 20- to 30-year period, so waste in a landfill may be undergoing several phases of decomposition at once. This means that older waste in one area might be in a different phase of decomposition than more recently buried waste in another area.
Phase I
During the first phase of decomposition, aerobic bacteria—bacteria that live only in the presence of oxygen—consume oxygen while breaking down the long molecular chains of complex carbohydrates, proteins, and lipids that comprise organic waste. The primary byproduct of this process is carbon dioxide. Nitrogen content is high at the beginning of this phase, but declines as the landfill moves through the four phases. Phase I continues until all available oxygen is depleted. Phase I decomposition can last for days or months, depending on how much oxygen is present when the waste is disposed of in the landfill. Oxygen levels will vary according to factors such as how loose or compressed the waste was when it was buried.
Phase II
Phase II decomposition starts after the oxygen in the landfill has been used up. Using an anaerobic process (a process that does not require oxygen), bacteria convert compounds created by aerobic bacteria into acetic, lactic, and formic acids and alcohols such as methanol and ethanol. The landfill becomes highly acidic. As the acids mix with the moisture present in the land-fill, they cause certain nutrients to dissolve, making nitrogen and phosphorus available to the increasingly diverse species of bacteria in the landfill. The gaseous byproducts of these processes are carbon dioxide and hydrogen. If the landfill is disturbed or if oxygen is somehow introduced into the landfill, microbial processes will return to Phase I.
Phase III
Phase III decomposition starts when certain kinds of anaerobic bacteria consume the organic acids produced in Phase II and form acetate, an organic acid. This process causes the landfill to become a more neutral environment in which methane-producing bacteria begin to establish themselves. Methane-and acid-producing bacteria have a symbiotic, or mutually beneficial, relationship. Acid-producing bacteria create compounds for the methanogenic bacteria to consume. Methanogenic bacteria consume the carbon dioxide and acetate, too much of which would be toxic to the acid-producing bacteria.
Phase IV
Phase IV decomposition begins when both the composition and production rates of landfill gas remain relatively constant. Phase IV landfill gas usually contains approximately 45% to 60% methane by volume, 40% to 60% carbon dioxide, and 2% to 9% other gases, such as sulfides. Gas is produced at a stable rate in Phase IV, typically for about 20 years; however, gas will continue to be emitted for 50 or more years after the waste is placed in the landfill (Crawford and Smith 1985). Gas production might last longer, for example, if greater amounts of organics are present in the waste, such as at a landfill receiving higher than average amounts of domestic animal waste.
A bioreactor landfill operates to rapidly transform and degrade organic waste. The increase in waste degradation and stabilization is accomplished through the addition of liquid to enhance microbial processes. By efficiently designing and operating a landfill, the life of landfill can be significantly extended, leachate is effectively detoxified and greenhouse gases are reduced. Landfill gases such as methane are fuel sources which are then used for clean energy production. Bioreactor landfills offer many benefits, such as :
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Decomposition and biological stabilization in years. Lower waste toxicity and mobility due to both aerobic and anaerobic condition. Reduce leachate disposal costs and leachate detoxification.
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A 15 to 30 percent gain in landfill space due to an increase in the density of waste mass. Increased landfill settlement due to rapid decomposition of waste.
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Significant increase in LFG generation that, when captured, is used for onsite energy use, or can be sold.e.
However, the anaerobic digestion in waste management on landfill has been recognized by United Nation Development Program and the research of Bioplastics Council in August 2013, as one of the most useful decentralized sources of energy supply.
If your plastic products being adopted & using EBA Additive, the degradable period can reduce to 5 to 10 years, which depends on the material thickness. Your product is then treated as carbon negative, and contributing to a greener world and creating energy from trash. Biodegradable plastic production will increase the biodegradation rates of landfills causing for more methane potential within landfill environments.
* Reference :
HONG KONG EMSD Production of landfill Gas
https://www.sciencedirect.com/topics/earth-and-planetary-sciences/landfill-gas
