Recycling Errors


March 25, 1993|By NIGEL SEARLE

VENICE, FLORIDA. — Venice, Florida -- How many times have you read statement such as, ''Each year we throw away enough aluminum to rebuild the U.S. air fleet,'' intended to give us a feel for the magnitude of the recycling problem? Have you ever wondered if such factoids are actually true?

Consider a couple of statements that have been published repeatedly, without attribution. I saw them most recently under the title ''Recycling Facts'' in the Sarasota Herald-Tribune last month.

* Each ton of recycled glass saves 9 millions gallons of fuel.

* The energy saved from recycling a glass bottle will light a 100-watt bulb for four hours.

Let's suppose an average glass bottle weighs four ounces. Since there are 2,000 pounds in a ton, there would be 8,000 bottles in a ton of glass. So, recycling 8,000 bottles would save 9 million gallons of fuel. Or, each bottle recycled would save 1,125 gallons of fuel. (That's 9 million divided by 8,000.) That seems like a big savings for just one bottle.

But we're also told that the energy saved from recycling one bottle -- or 1,125 gallons of fuel -- will light a 100-watt bulb for four hours. If I ever have to run a generator to provide electricity for my home, I hope I don't have to burn more than a thousand gallons of fuel to light a 100 watt bulb for four hours.

My guess is that the second statement is true. The amount of energy used to light a 100-watt bulb for four hours is fairly small. It's plausible that it could be the same as the energy saved by recycling a bottle.

But the first statement is just plain wrong. Maybe a ton of recycled glass saves 9,000 gallons of fuel, rather than 9 million. But that would still leave 1.125 gallons of fuel required to light a 100-watt bulb for four hours. That much gasoline could drive a typical car at 30 miles an hour for more than an hour; and it seems a car should use lots more energy than a 100-watt light bulb, not just four times as much.

Maybe a ton of recycled glass saves 900 gallons of fuel.

Sometime, somewhere, someone made a mistake. The answer they came up with was wrong by a factor of at least 1,000 -- maybe 10,000. But their numbers have been accepted as gospel, and have been recycled over and over.

Just how much aluminum is there in the U.S. air fleet, anyway?

Nigel Searle is a math major and skeptic.

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