Finding A Sustainable Future at The Dump
The economic crisis has now hit the bottom of the barrel - the trash barrel, that is.
If we were to look at a garbage landfill from 200 feet away, most of us would see what appears to be a landscape of unidentifiable trash. If we dared to stand in the landfill, we would be able to identify familiar solid-waste products such as paper, cardboard, metal cans, plastic and glass bottles, scrap metal, and a host of other items. But what if we were able to take a really close look - down to the atomic level? We would see trillions of molecules made up of carbon, hydrogen, and oxygen, the building blocks of precious fuel to run our cars, heat our homes, and generate electricity. We would see trillions of molecules of inorganic chemicals that could be transformed into building and construction materials to save energy and preserve our natural resources.
For years, the paradigm for waste recycling has only considered the value of waste on the material level. We recycle plastics to plastics, rubber to rubber, paper to paper - we simply refabricate the same molecules into similar products of the same molecules.
This isn't a bad idea as long as the demand for those products remains strong enough to support the cost of recycling. But we are currently witnessing a drastic drop in the market for traditional recyclables because of the downturn in our economy and the economies of global trading partners. Also, recycling and refabricating these materials often uses more energy than creating virgin products. The result - more and more recyclable materials are finding their way back into a landfill system that is getting dangerously close to capacity and continues to spew greenhouse gases.
There are a number of new technologies that can come to the rescue of this landfill dilemma.
One such technology is called plasma-enhanced melter. With it, virtually any waste product can be fed into a closed chamber where it is superheated to temperatures of between 10,000 and 20,000 degrees Fahrenheit using an electricity-conducting gas called plasma. This is not an incineration process that creates greenhouse gases, hazardous ash, and other air pollutants. The intense heat of the plasma gasification process actually rearranges the molecular structure of the waste, transforming organic (carbon-based) materials into an ultra-clean, synthetic gas (syngas) rich in carbon and hydrogen. The clean gas can be made a substitute for natural gas for heating, converted to liquid transportation fuels, or even used for electricity generation.
The gasification technology is not simply another science project. In fact, it is already being used in the United States as well as other countries. In 2003, Kawasaki Heavy Industries in Japan purchased a plasma-enhanced melter system to destroy PCBs and asbestos. Global Plasma in Taiwan has been converting industrial and medical wastes into clean electric power since 2005. Last year, Dow Corning signed a 10-year contract and construction has started to use this technology to convert chemical waste into process-quality hydrochloric acid and enough clean synthetic gas to heat several thousand homes. Fulcrum Bioenergy is building a facility outside of Reno, Nev., that will have the capacity to process 90,000 tons of municipal solid waste into 10.5 million gallons of ethanol per year. A 25-ton-per-day, demonstration-scale plasma-enhanced melter unit in Richland, Wash., is capable of processing 20 percent of the town's waste.
Plasma gasification technology like the plasma-enhanced melter creates a new paradigm for waste recycling and sustainability, because it actually rearranges the atoms in molecules of low-value waste into molecules of high-value products. Over the past 1,000 years we have called this process "alchemy." Perhaps in the next 1,000 years we will call it "a sustainable future."
© 2009 The Boston Globe