Despite the numerous potential benefits of organic waste utilization, including environmental protection, investment and job creation, the United States currently only has 2, operating biogas systems, representing less than 20 percent of the total potential.
Biogas is produced after organic materials plant and animal products are broken down by bacteria in an oxygen-free environment, a process called anaerobic digestion. Biogas systems use anaerobic digestion to recycle these organic materials, turning them into biogas, which contains both energy gas , and valuable soil products liquids and solids.
Anaerobic digestion already occurs in nature, landfills, and some livestock manure management systems, but can be optimized, controlled, and contained using an anaerobic digester. Biogas contains roughly percent methane, percent carbon dioxide, and trace amounts of other gases. The liquid and solid digested material, called digestate, is frequently used as a soil amendment. Some organic wastes are more difficult to break down in a digester than others. Food waste, fats, oils, and greases are the easiest organic wastes to break down, while livestock waste tends to be the most difficult.
Mixing multiple wastes in the same digester, referred to as co-digestion, can help increase biogas yields. Warmer digesters, typically kept between 30 to 38 degrees Celsius Fahrenheit , can also help wastes break down more quickly.
After biogas is captured, it can produce heat and electricity for use in engines, microturbines, and fuel cells. Biogas can also be upgraded into biomethane, also called renewable natural gas or RNG, and injected into natural gas pipelines or used as a vehicle fuel. The United States currently has 2, operating biogas systems across all 50 states, and has the potential to add over 13, new systems. Stored biogas can provide a clean, renewable, and reliable source of baseload power in place of coal or natural gas.
Baseload power is consistently produced to meet minimum power demands; renewable baseload power can complement more intermittent renewables. Similar to natural gas, biogas can also be used as a source of peak power that can be rapidly ramped up. Using stored biogas limits the amount of methane released into the atmosphere and reduces dependence on fossil fuels. The reduction of methane emissions derived from tapping all the potential biogas in the United States would be equal to the annual emissions of , to 11 million passenger vehicles.
Based on a waste-to-wheels assessment, compressed natural gas derived from biogas reduces greenhouse gas emissions by up to 91 percent relative to petroleum gasoline. Diverting that waste to anaerobic digestion would turn a cost into an opportunity, generating revenue from energy production and co-products. Source: New York Times , June 2, In addition to climate benefits, anaerobic digestion can lower costs associated with waste remediation as well as benefit local economies.
Building the 13, potential biogas systems in the United States could add over , temporary construction jobs and 23, permanent jobs. Anaerobic digestion also reduces odors, pathogens, and the risk of water pollution from livestock waste. Digestate, the material remaining after the digestion process, can be used or sold as fertilizer, reducing the need for chemical fertilizers. Digestate also can provide additional revenue when sold as livestock bedding or soil amendments.
Around 30 percent of the global food supply is lost or wasted each year. In alone, the United States produced roughly billion pounds Food should be sent to landfills as a last resort. Unfortunately, food waste makes up 21 percent of U. Most of this waste is sent to landfills, where it produces methane as it breaks down. While landfills may capture the resultant biogas, landfilling organic wastes provides no opportunity to recycle the nutrients from the source organic material.
But even if this goal is met, there will be excess food that will need to be recycled. The energy potential is significant. As just one example, with tons of food waste per day, anaerobic digestion can generate enough energy to power to 1, homes each year.
Fat, oil, and grease collected from the food service industry can also be added to an anaerobic digester to increase biogas production. Landfills are the third largest source of human-related methane emissions in the United States. Share sensitive information only on official, secure websites. JavaScript appears to be disabled on this computer. Please click here to see any active alerts. Anaerobic digestion is the natural process in which microorganisms break down organic materials.
Anaerobic digestion happens in closed spaces where there is no air or oxygen. All anaerobic digestion systems adhere to the same basic principles whether the feedstock is food waste, animal manures or wastewater sludge.
The systems may have some differences in design but the process is basically the same. Learn more about how anaerobic digestion works. Biogas is generated during anaerobic digestion when microorganisms break down eat organic materials in the absence of air or oxygen.
Biogas is mostly methane CH 4 and carbon dioxide CO 2 , with very small amounts of water vapor and other gases. The carbon dioxide and other gases can be removed, leaving only the methane. Not long after, in , the UK used anaerobic digestion to convert sewage into biogas, which was then used to light street lamps. For the next century, anaerobic digestion was primarily used as a means to treat municipal wastewater. The goal was to decrease energy poverty in rural areas, and make cleaner cooking fuels more accessible in remote areas.
Close to one third of the global population still uses firewood and other biomass for energy, causing devastating health and environmental problems. Link to blog post on developing countries. Since then, family-sized biogas units are gaining more attention and popularity as both a means of reducing household waste and as a means of providing clean renewable energy to families throughout the world.
In the past 15 years, countries around the globe are adopting biogas programs to make both household biogas systems and larger anaerobic digestion plants accessible, efficient, and convenient. As landfills get illegally overloaded, and as the release of methane poses more worrying problems, the benefits of using biogas systems to convert waste into energy are increasingly more relevant and important. Many Uses of Biogas:Biogas can be produced with various types of organic matter, and therefore there are several types of models for biogas digesters.
Some industrial systems are designed to treat: municipal wastewater, industrial wastewater, municipal solid waste, and agricultural waste. Small-scale systems are typically used for digesting animal waste. And newer family-size systems are designed to digest food waste. The resulting biogas can be used in several ways including: gas, electricity, heat, and transportation fuels. For example, in Sweden hundreds of cars and buses run on refined biogas. The biogas in Sweden is produced primarily from sewage treatment plants and landfills.
Another example of the diversified uses of biogas is the First Milk plant. New anaerobic digestion plants like these with fascinating stories keep popping up every day! Small-scale, or family-size biogas digesters are most frequently found in India and China. However, the demand for such units is growing rapidly throughout the world thanks to more advanced and convenient technologies, such as HomeBiogas.
As the modern world is producing more and more waste, individuals are eager to find ecologic ways to treat their trash. Traditional systems typically found in India and China focus on animal waste. Due to a lack of energy in rural areas combined with a surplus of animal manure, biogas digesters are very popular, useful, and even life-changing. In many developing countries, biogas digesters are even subsidized and advocated by the government and local ministries, who see the variety of benefits produced from using biogas.
In addition to having a clean renewable energy provide gas in the kitchen, many families make extensive use of the fertilizer by-product that biogas digesters provide. In African countries, some biogas users even turn a profit by selling the bio-slurry by-product produced by biogas systems. This bio-slurry is different from the liquid fertilizer that is produced daily.
Bio-slurry refers to the most decomposed stage of the organic matter, after it has been broken down in the system. Bio-slurry sinks to the bottom of the biogas system, and with the help of modern units like HomeBiogas, is easily emptied out once accrued usually an annual process. This bio-slurry is in fact a nutrient-dense sludge that provides lots of benefits to soil, and can increase productivity of vegetable gardens. As the application and efficiency grows, biogas can make a significant impact on reducing greenhouse gases.
0コメント