Shopping trips to Wal-Mart can be quite depressing. Today, however, I was pleasantly surprised. What greeted me as I slinked into the store (other than a creepy old man) were Sun Chips in compostable bags. Intriguing.
After delving into subject, I discovered that the bags are apparently manufactured by a company called NatureWorks, which specializes in creating packaging from corn. The bags start as dextrose (a sugar) derived from corn which is then fermented and becomes lactic acid (the same chemical that causes sore muscles after a workout). The lactic acid is then polymerized, or attached to one another to make a long chain of lactic acid molecules. The polymerized lactic acid can then be used like a plastic (which is also a polymer).
The cost of such a process is apparently now competitive with traditional plastics, and, of course, is more environmentally friendly. Not only are these products compostable, but they do not rely on oil to manufacture.
There are potential problems with this system, however. Corn is a food crop, and as we are experiencing with biofuel, using it for other purposes can drive up food costs. Corn also requires quite a bit of energy and water to grow. With this being said, the technology is simple enough that it can easily be used with some other source of sugar – perhaps a microbe – that will be more energy efficient.
Unfortunately, the Sun Chip bags are not completely made of this lactic acid polymer, but the company assures that they will be as soon as possible. And they are still compostable, though apparently they will not degrade in landfills (at least very quickly). Never-the-less, it is a noble effort and I, for one, encourage people to support it.
Learn more:
• Farrington, D.W.; Lunt, J.; Davies, S; Blackburn, R.S.; “Poly(lactic acid) fibers.” Biodegradable and sustainable fibres. Woodhead Publishing Limited, 2005. Chapter 6.
• http://www.natureworksllc.com/
• http://www.sunchips.com/healthier_planet.shtml
Tuesday, February 23, 2010
Friday, February 5, 2010
Clean power from trash?
Imagine your garbage morphing into the electricity that powers your home. Not only is this fantasy possible, but plans are already underway for it to be a reality, right here in New Orleans.
The technology is called plasma arc gasification. It utilizes super heated (over 7000 degrees Centigrade) gas called plasma to gasify or melt the trash that is fed into it. Plasma is also ionized, meaning that it carries an electric charge and generates a magnetic field. A frequently observed instance of such a plasma field is lightning.
Once the garbage is exposed to the plasma arc, the molecules of the substances break apart into pure atomic elements. The organic components of the trash become a gas – similar to natural gas – that can be used to generate power. The inorganic parts melt and become what is known as “slag.”
Despite some protests by local environmental groups, the facility will theoretically be environmentally friendly. Not only would the plant reduce landfill use, but since the actual molecular composition of the garbage is changed by this process, the plasma plant can take potentially hazardous materials and render them harmless. Dr. Louis J. Circeo, Director of the Plasma Applications Research Program at Georgia Tech Research Institute, claims that the plants can “accept all solid and liquid waste” including hazardous, toxic, and medical wastes.
Unlike other waste-to-energy facilities currently in the United States, plasma gasification does not burn the trash, thus eliminating a potential pollution problem. “It creates no waste” says D’Juan Hernandez, the owner of Sun Energy Group, the company planning to build a plasma gasification plant in New Orleans. “There are two products – slag, which can be reformed into construction materials, and syngas, which is used for power generation.” In a recent presentation, Dr. Circeo explained that the slag generated by plasma gasification can be used for concrete, asphalt, insulation, and can also produce recyclable metals.
However, since the molten slag can be molded into almost any shape, there are many other possible uses for it. In a recent book, Prescription for the Planet, Tom Blees suggested a use for slag that could assist with another environmental problem. Blees stated that “The molten slag could be poured into molds of various shapes optimally designed for use as artificial reefs.”
Hernandez also explained that using the syngas to create power will generate some emissions, but the plant should have emissions well under regulation standards and little to no other environmental consequences. Plasma gasification will not over-ride normal recycling, however. Recyclable materials will be sorted out at the facility and sold.
This technology may seem quite ground-breaking, but it has actually been used in several other countries for many years. Japan has been successfully operating two gasification plants for seven years. Canada, Taiwan, and England also have operational plasma gasification facilities. Plants similar to the one planned in New Orleans are currently under development in Florida, Pennsylvania, Minnesota, and Massachusetts.
Hernandez stated that Louisiana was targeted as a location for a gasification plant because “it is an industrial state and it has a high utilities cost and high landfill use rates.” According to Hernandez, the new plant is expected to create over one hundred jobs in the area and produce 115 megawatts of power by processing 2,500 tons of garbage daily. It is expected to be operational by the end of 2012.
The technology is called plasma arc gasification. It utilizes super heated (over 7000 degrees Centigrade) gas called plasma to gasify or melt the trash that is fed into it. Plasma is also ionized, meaning that it carries an electric charge and generates a magnetic field. A frequently observed instance of such a plasma field is lightning.
Once the garbage is exposed to the plasma arc, the molecules of the substances break apart into pure atomic elements. The organic components of the trash become a gas – similar to natural gas – that can be used to generate power. The inorganic parts melt and become what is known as “slag.”
Despite some protests by local environmental groups, the facility will theoretically be environmentally friendly. Not only would the plant reduce landfill use, but since the actual molecular composition of the garbage is changed by this process, the plasma plant can take potentially hazardous materials and render them harmless. Dr. Louis J. Circeo, Director of the Plasma Applications Research Program at Georgia Tech Research Institute, claims that the plants can “accept all solid and liquid waste” including hazardous, toxic, and medical wastes.
Unlike other waste-to-energy facilities currently in the United States, plasma gasification does not burn the trash, thus eliminating a potential pollution problem. “It creates no waste” says D’Juan Hernandez, the owner of Sun Energy Group, the company planning to build a plasma gasification plant in New Orleans. “There are two products – slag, which can be reformed into construction materials, and syngas, which is used for power generation.” In a recent presentation, Dr. Circeo explained that the slag generated by plasma gasification can be used for concrete, asphalt, insulation, and can also produce recyclable metals.
However, since the molten slag can be molded into almost any shape, there are many other possible uses for it. In a recent book, Prescription for the Planet, Tom Blees suggested a use for slag that could assist with another environmental problem. Blees stated that “The molten slag could be poured into molds of various shapes optimally designed for use as artificial reefs.”
Hernandez also explained that using the syngas to create power will generate some emissions, but the plant should have emissions well under regulation standards and little to no other environmental consequences. Plasma gasification will not over-ride normal recycling, however. Recyclable materials will be sorted out at the facility and sold.
This technology may seem quite ground-breaking, but it has actually been used in several other countries for many years. Japan has been successfully operating two gasification plants for seven years. Canada, Taiwan, and England also have operational plasma gasification facilities. Plants similar to the one planned in New Orleans are currently under development in Florida, Pennsylvania, Minnesota, and Massachusetts.
Hernandez stated that Louisiana was targeted as a location for a gasification plant because “it is an industrial state and it has a high utilities cost and high landfill use rates.” According to Hernandez, the new plant is expected to create over one hundred jobs in the area and produce 115 megawatts of power by processing 2,500 tons of garbage daily. It is expected to be operational by the end of 2012.
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