One of the newest and most innovative methods for handling municipal waste is a process called plasma gasification. If it sounds complicated, that’s because it is. It’s also very expensive to build a plasma gasification facility, so that’s a major drawback. However, it’s probably the cleanest, most eco-friendly waste management option to date.
The Air Force Uses Plasma Gasification
The Air Force has been operating a 6,400 square-foot plasma gasification plant in the Florida panhandle for several years now. It’s a small-scale plant that processes about 10 tons of garbage per day. The plant produces about 350 kilowatts of electricity using the plasma arc gasification (its official name) process.
David Robau, an environmental scientist for the Air Force, stresses the environmental benefit offered by this new technology. He says, “This is not incineration. This is gasification, so it’s a lot cleaner, a lot better for the environment.” He adds, “Effectively, 100% of all the metals on the (Air Force) base are being recycled.” Sounds too good to be true. So... is it?
Pros and Cons of Plasma Gasification
Based on early research, it’s pretty tough to find any negatives associated with sending municipal waste to plasma gasification facilities. I’ve already mentioned the biggest drawback – cost. Cities would have to fork over a pretty penny to build and operate a plasma gasification plant.
A proposed large-scale plant in Reno, Nevada will cost $105 million to build. Building a new landfill is far less expensive, and that’s the reason it’s still the number one choice of cities and municipalities across the United States. A second potential downfall of a plasma gasification waste processing plant is the energy requirements. It takes a relatively large amount of electricity to fuel such a plant.
That said, much of the electricity needed for operations can be produced on-site, such as is the case at the Air Force facility. The benefits of this type of waste facility are plentiful. Here’s a short list:
- Far less toxic emissions compared to landfills or other waste-to-energy facilities
- Toxic waste, like asbestos and medical waste, can be safely processed.
- Syngas is a byproduct of the process, which is as clean or cleaner than natural gas, and can be used to produce energy, like biofuel.
- Metal is nearly 100 percent recoverable and can be used to make new steel.
- Low dioxin emissions
- Waste is shrunk to 1 percent its original size—one-tenth the size of byproducts of incineration.
How Plasma Gasification Works
As previously stated, it’s a pretty complicated process, but here’s the gist of it:
- Waste enters the facility and gets shredded into pieces no larger than two-inches in size.
- The small chunks of garbage get fed into an oxygen-poor gasification chamber.
- The trash is heated to 9,000 degrees using powerful arcs of electricity to create plasma.
The gasification process instantly disintegrates wood, turns plastic to gas, and melts metal/glass into a molten state. The byproducts of the process meet or exceed standards for disposal, but Robau believes it could be reused as a construction aggregate material.
The gases produced during the initial burn – carbon monoxide and hydrogen – exit the furnace, get filtered several more times, and are used to produce syngas. The molten metal pools at the bottom of the furnace chamber. It’s allowed to cool, and it can then be used to produce steel or other metal products. The process also produces hydrochloric acid and sodium bisulfate, both of which can be sold for profit.
The proposed plasma gasification plant in Reno will have the capacity to handle 400 tons of garbage per day. The plant is scheduled to open in 2014. Other proposed plants are scattered throughout the U.S., but no firm commitments have been made as of this date.
New York City has entertained the idea of building a plasma gasification waste facility capable of handling 900 tons of waste per day.
A small-scale test facility in Arlington, Oregon has been in operation for several years, and this facility handles about 25 tons of waste per day.
Waste-to-energy technology has progressed at a rapid pace over the last 5-10 years due to an increased concern over clean energy and sustainability. Plasma arc gasification seems like a viable and eco-friendly solution to manage the estimated 250 million tons (and growing) of municipal waste the U.S. produces each year. Could plasma gasification mark the end of traditional landfills as we know it? Odds are, probably not—at least not anytime soon. Landfills are still useful today and will be in the future, but the U.S. is definitely heading in a more eco-friendly direction when it comes to handling its trash.
Via: New York Times
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Step 1: Find the right size dumpster for your project and disposal needs
Step 2: Understand what does and doesn't affect dumpster pricing
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