Energy saving

Garbage as an energy source


Waste can be a source of clean energy? While in Naples a technology that uses a waste-eating bacterium is patented, in the United States 2400 landfills lend their waste for the production of clean energy. Of course, wind and solar power continue to be the most fascinating renewable sources but garbage also wants its part!

The technology that allows the conversion of waste into energy is now mature. In the United States there are over 500 plants already active and just as many sites waiting to operate from energy plants by converting the gases obtained from waste into electric energy. A great one energy saving for the environment that every year has to dispose of or store tons of rubbish emitting CO2 and at the same time produce electricity by emitting CO2 and manufacture other objects destined to become garbage!

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The recovery of gas from landfills was already a reality in 1975, as is stated Jean Bogner, Nobel Peace Prize laureate in 2007 and geochemical expert at the University of Illinois, Chicago. Compared to the energy obtained from biomass which in Italy could yield 16 billion euros, the energy obtained from urban waste has a great advantage: there is already a good waste collection system.

When we talk about "gas from landfills " we refer to methane, generated by the decomposition of organic material in municipal solid waste: waste food, garden waste, leaves, grasses, wood, paper ... this gas in the USA represents about a quarter of total anthropogenic emissions. Not only the United States, but also in Germany there are waste treatment plants, so much so that Italy pays Germany for the export of local waste, waste that German plants transform into energy.

Garbage needs to be re-evaluated, beyond the more classic recycling works, waste has a great value in the energy sector. How is energy produced from waste? The landfill gas is extracted by means of aspirators that convey the methane in a tube. Here the gas is oxidized during a combustion process which will produce carbon dioxide and water. With combustion, the gas will be used as a substitute for fossil fuels.

It is necessary that the gases produced by landfills are exploited for the production of energy otherwise they could cause great damage to the environment: methane has a high capacity to trap heat, this greenhouse gas heats the earth 23 times more than the so-called CO2 . The gas, if collected, can feed an industrial boiler or set in motion a turbine capable of generating electricity.

Using gas to drive a turbine and generate electricity could be an inconvenient solution due to the high costs, but let's not forget that there are many methane cartherefore, this gas could undergo a compression or liquefaction process to be used in vehicles or it could convey directly into the pipelines that carry the gas to homes. A limit of methane produced by waste is purity: if the gas is not treated it is rich in impurities that make it less attractive for a mass market.


Video: LANDFILL PROCESS (October 2020).