Energy From Trash
Waste-to-Energy refers to the practice of recovering energy from the destruction of non-recyclable waste materials. Techniques like combustion, anaerobic digestion, and landfill gas recovery can be used to generate electricity or heat and to capture natural gases.
Humans have employed basic forms of waste-to-energy conversion, such as using farming or logging waste as fuel for heating, since at least 3000 BCE.
Modern Industrial Incineration
The first notable example of a modern waste-to-energy system occurred in Nottingham, England in 1874, with an incinerator built by Manlove, Alliott & Co. Ltd. Incineration systems burn organic waste matter and transform it into gas, heat, and ashes.
Contemporary waste-to-energy methods also include gasification, which produces synthetic fuels and hydrogen, and thermal depolymerization, for the production of crude oil. Anaerobic digestion of waste by bacteria can produce usable natural gases, and fermentation can result in the production of useable hydrogen and lactic acids. The methane gas produced from decomposing waste can also be captured and used to produce energy and various compounds through landfill gas recovery systems.
Space and Energy Savings
Waste-to-Energy can be a significant source of valuable energy, which can be used to satisfy public and private power needs.
In the case of incineration, the total volume of waste can be dramatically reduced, sometimes by as much as 95 percent, cutting storage needs and freeing space in landfills. Waste-to-Energy facilities can often supply their own power, decreasing overall energy needs for waste disposal and offsetting emissions.
Objections to Waste-to-Energy
The primary objection to waste-to-energy processes involving combustion relates to emissions risks. If the facility is not managed properly, toxic gases like dioxin and furans may be released in the air when solid waste is burned. Also, waste that is burned to create energy cannot be recycled for material re-use, and the facilities themselves can be expensive to run.
Compared to fossil fuel power plants, plants that use municipal solid waste to generate power typically use a similar amount of water per unit of electricity generated. The use of that water comes with its own environmental repercussions, including impact upon local wildlife, human needs, and the discharge of polluted water.