A Hot Idea To Make Trash Disappear

March 19, 2006
Commentary By Tom Condon

I have seen the future of trash. It's hot. It's very hot. It's 7,000 degrees Celsius.

I speak of plasma arc, an emerging technology that can, among other things, zap garbage with so much heat that mountains of trash turn into piles of pebbles (and you can reuse the pebbles). There's no ash, no emission and no pollution.

I saw a presentation on plasma arc last week in Hartford by one of the field's leading experts, Louis J. Circeo of Georgia Tech.

It's almost breathtaking, what this someday might do for Greater Hartford. Not only doesn't plasma arc require a landfill, it can melt an existing one.

As you are doubtless aware, we have a garbage problem. Connecticut generates 400,000 more tons of trash than we can dispose of each year, and so we have to ship it out of state, at considerable expense. The Hartford landfill is due to end its overlong existence late next year, and many other landfills in the state are close to the end of their useful lives as well.

We can and should do better on the supply end - more recycling and not as much packaging. That would help, but it won't solve the trash problem. Plasma arc might.

Circeo, a stocky, gray-haired, avuncular fellow, explained that plasma arc is essentially artificial lightning. Plasma is ionized gas, which some consider the "fourth state of matter." Through a process I won't pretend to understand, electrical current in plasma can create a "plasma torch" that burns at a temperature in excess of 7,000 degrees C. That is three times hotter than the temperature at which fossil fuels burn. It is hotter than the surface of the sun.

What it does is cause organic compounds to dissociate into their elemental components, which then recombine as simple gases that can be burned for fuel. The inorganic residue melts into a substance much like black volcanic glass, which can be used for bricks or roadfill.

Scientists at NASA refined plasma arc technology in the 1960s to test heat shields for space vehicles. The steel and metallurgical industries use it, and environmental engineers began working with it in the 1980s to treat municipal, hazardous and toxic wastes, Circeo said.

The process will work on medical, electronic, asbestos - about any kind of waste short of spent nuclear fuel rods.

Thus far, three plasma arc waste-to-energy plants have been built, all in Japan. The French have a plasma plant for disposing of asbestos. This country has a few projects on the drawing board, including a plant in Atlanta for scrap tires. One of the remarkable potentialities, though it is just emerging from the lab, is something called in-situ remediation. The idea is to bore holes in existing landfills, drop the torch down into the holes and zap the contents. Circeo said it can reduce the mass of a landfill by 90 percent and eliminate environmental hazards at the bottom of the dump. It then becomes possible to reuse the land. This would put nearly 100 acres along the river in the North Meadows - the site of the current landfill - back in play. Imagine.

"If you wanted to, you could use it for a landfill again," Circeo said. I think not.

As with many new technologies, there are challenges with size and cost. The largest plant now operating handles 300 tons of municipal waste a day. There's one in the planning stages that will do 1,000 tons. The 70 towns in the Connecticut Resources Recovery Authority's area generate about 2,500 tons of trash a day. The cost can now be gotten down to a competitive rate, $50-$80 a ton, though the Georgia Tech researchers have further cost-reduction measures in the pipeline.

One is to produce rock wool, a sought-after insulation and soundproofing material, with the inorganic residue. Another is to hook up a plasma arc plant to a coal-burning power plant. By using parts of the coal-fired plant, such as the electrical generator and gas treatment chamber, the cost of the trash plant is cut in half.

Where does all of this leave Hartford? At the moment, just getting started.

Former city Councilman Mike McGarry and city Councilman Robert Painter have been looking at this technology for some time, and prevailed on public works Director Bhupen Patel to visit Georgia Tech and see for himself. Patel, no pushover for the latest thing, was impressed. The city and the nonprofit group Hartford 2000 brought Circeo to the city last week in the hope of getting something started.

The folks at CRRA once dismissed this - perhaps not incorrectly - as too expensive. But they've now gotten interested in it.

It's certainly something to watch, and Patel is forming a study group to further examine the process. It might be possible to build a small plant to handle, say, medical waste, which is now shipped out of state at considerable expense. If that worked, we could go bigger.