Biogas became another alternative to reuse organic waste! See how this works!

Biogas became another alternative to reuse organic waste! See how this works!

Biogas is the energy produced by the gas released during the decomposition of organic waste. This is another super-timely natural alternative for electricity generation! Thus, biogas helps cleaning the air as well as to reducing diseases due to the landfill's waste volume reduction!

The gas produced by bacterial activity is transformed into carbon dioxide after being burned, in order to be reused in the form of a biogas

Technically speaking, what happens, actually, is a conversion of the chemical energy of the gas released - from the dumps or landfills - into mechanical energy, aka biogas, through a controlled combustion process.

The generation of biogas begins after the first three months following the disposal of the waste and can last for a period of 30 years or more. The use of biogas is done by installing drains that reach all layers of garbage.

"The waterproofing of the base and coverage of the landfill is a measure that contributes both to the process of degradation of organic matter (increasing biogas production), and also to prevent contamination of soil and groundwater from the site."

Biogas, in gaseous form, has the following chemical composition:

  • 60% of methane hydrocarbon (CH4)

  • 35% of carbon dioxide (CO2) 

  • 5% of other compounds such as hydrogen, nitrogen, ammonia, hydrogen sulfide, carbon monoxide, amines, and oxygen.

The amount of methane can reach 80%, depending on how the biogas was produced!

Methane gas is also known as "swamp gas", because it is formed in wetlands, with low oxygenation, by the decomposition of organic material deposited in lakes. Another name that methane gas receives is "firedamp", a flammable gas found in coal mines. It is particularly found in areas where the coal is bituminous.

Sewers are another source of methane gas

The collected methane from sewers is transported to the lifting station, from where the larger particles are retained, then destined to a local sewage treatment plant.

In fact, solid waste goes to the landfill, while the liquid stuff goes to the biodigester, a reactor, where the process of digestion of organic matter occurs, by the bacteria in it.

Post-treatment of an organic waste facility

3 situations to use biogas as an energy source:

  1. Direct combustion

  2. Gasification

  3. Reproduction of the natural process when microorganisms in an anaerobic environment produce the decomposition of organic matter and, consequently, produces biogas

A brief history of biogas

Biogas was discovered in 1667 but only recognized as an energy source in the 19th century by Ulysse Gayon, a student of Louis Pasteur, who performed anaerobic fermentation of a mixture of manure and water at 35ºC. At this temperature, Gayon was able to obtain 100 liters of gas per m3 of matter.

In 1884, Louis Pasteur himself presented to the Academy of Sciences the works of his student. The fermentation obtained in the experiment became a cheaper source of energy for heating and lighting of regions furthest from big city centers.

Biogas can be stored in facilities with low-cost infrastructure!

Other benefits of biogas:

  • Renewable: landfill and sewage waste never runs out
  • Raw material sources: easy to obtain at low-cost
  • Waste reduction: with reduced volume in dumps, it lows the risk of disease and soil contamination
  • Greenhouse effect: lowering the level of garbage, low emission of gases in the atmosphere that feeds the so-called ozone hole
  • Fertilizer: solid residues from waste can become organic fertilizer or biofertilizer, known as a biogas by-product

    The device that produces biogas

    The biodigester is a device responsible for the collection and generation of energy from waste or sewage gases. It is closed equipment in which organic matter is introduced to be decomposed by several anaerobic microorganisms.

    "In the biodigester, the process of digestion of organic matter is performed by bacteria, in the absence of oxygen and in an environment with stabilized pH and temperature. In this process, the organic matter will be converted into biogas, predominantly composed of methane and carbon gas"

    The biodigester in the country

    The biodigester is super-important for rural producers who can generate electricity, from the reuse of their organic waste:

    • Cane: vinasse, filter pie, leftover bagasse, and cane straw

    • Waste from rural production: pig, bovine and poultry manure

    • Agricultural waste

    • Washing and feed waste

      The reuse of organic waste in the field relieves rural producers, who do not know what to do with waste since it is required by law that they have a proper destination for them in order to maintain local sustainability. 

      By Marco Veado - THINK GREEN

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