By Donella Meadows
–September 3, 1987–
About a month ago I got a mailing from a national environmental group, warning about the very incinerator to which my garbage wends its humble weekly way. It’s a brand-new, waste-to-energy plant in Claremont, New Hampshire, built and operated by Signal Environmental Systems.
“Watch this plant!” the flyer said. “This is the second incinerator in the USA to be fitted with a dry scrubber and baghouse filter. Ash testing from March to June 1987 has confirmed that the better the industry gets at controlling air emissions, the more toxic the ash becomes. The plant is converting four tons of garbage into one ton of hazardous waste.” My garbage? Toxic ash? Hazardous waste?
A week later a headline in the local paper said, “Latest Results Are In, Incinerator Ash Shown Cleaner”. Shortly thereafter another headline said: “Incinerator Ash Testing Questioned”. Some experts were saying that the tests weren’t done properly, that they aren’t very informative anyway, and that the ash should not be allowed anywhere near our landfills. Other experts were replying, in polite expert fashion, that that is a lot of balderdash.
When experts disagree about matters of public interest, I assume it’s time for ordinary folks to find out what’s going on. Anyway, I consider it a basic rule of good citizenship to Know Where Your Garbage Goes, and I had never laid eyes on my incinerator. So I paid it a visit.
Warning: the following material is an explicit description of how a modern garbage incinerator looks, smells, and works. If you think you don’t need to understand such things, consider that wherever you live, there’s likely to be an incinerator near you — there are 17 planned for New Hampshire and over 1000 for the nation over the next ten years. One of these things will certainly cost you money; it may pollute you as well.
The $25 million Signal plant is in Claremont’s industrial-park-in-the-countryside, surrounded by corn, forests, and houses with blooming gardens. It looks like any new industrial plant, an ugly, imposing sheet-steel block of a building, a tall rust-colored smokestack. Nothing visible comes out the stack.
All day garbage trucks pull up the drive and onto the weighing platform. The computer inside has memorized each truck’s weight; it registers the weight of the trash and totes up the tipping fee ($40/ton at the moment). About 200 tons of garbage arrive per day, mostly from the 26 towns in the Solid Waste District, some contracted by Signal from private dumpers.
The trucks drive onto the tipping floor, a massive concrete-lined hall that can hold a thousand tons of trash. Air is drawn into the tipping floor and out through the boilers to reduce odor, but on the floor your nose tells you plainly that the main business here is garbage. The trucks dump it, a bulldozer shoves it up against the wall in impressive mountains, another bulldozer drops loads of it into the chutes that feed the two boilers. There is no separating, milling, crushing. Whatever we throw away — bottles, cans, Pampers — gets tossed, all mixed up but pretty much intact, into the boilers. That’s why this is called a mass-burn facility.
The boilers are like woodstove fireboxes only much bigger. They have small, heavy windows through which you can see the enormous fires. Their floors are stair-stepped; the burning trash moves slowly downward and the ash falls through grates and is quenched with water. This “bottom ash” is seared, unburnable trash, mostly metal and glass. From its daily 200 tons of garbage, the plant produces about 60 tons of ash. The incinerator doesn’t eliminate the need for a landfill; it just reduces the volume going there.
The heat of the boilers makes steam, which goes through a turbine to generate electricity. When fully fired up, the Claremont plant produces 4.2 megawatts, about 25% of the needs of the city of Claremont, about 1/250 as much as a nuclear power plant.
The gases coming off the burning trash are full of nasty stuff, and that’s why there are two anti-pollution devices on this plant, a scrubber and a baghouse.
The scrubber runs the gases through dry lime, which neutralizes the sulfur dioxide and hydrochloric acid that are causes of acid rain. The baghouse is a series of huge asbestos-and-teflon bags, like vacuum cleaner bags. They catch about 75% of the fine smoke particles called fly ash. The fly ash contains some of the most dangerous pollutants, including dioxins and heavy metals — lead, cadmium, mercury, chromium.
The fly ash from the baghouse is combined with the bottom ash and trucked to a landfill in Rockingham, Vermont. A new ash landfill is being prepared in Newport, N.H., just 1000 feet from the Sugar River, which is the drinking water supply for Claremont.
Is that ash safe? Will the pollutants in it blow around in the air or leach out into the groundwater? That’s what the experts are arguing about. While they argue, the Claremont plant is operating, creating 60 tons of perhaps-safe, perhaps-hazardous ash a day, under the all-American assumption that industries, like people, are innocent until proven guilty. Next week: getting the lead out of our ash.
Copyright Sustainability Institute 1987