May 1, 2003
How 220,000 milk jugs became a bridge made entirely of recycled plastic.
While officials in New York City have been scratching their heads about what to do with the tons of plastic collected by the municipal recycling effort—going so far as to eliminate the glass-and-plastic program last summer—two materials researchers and an entrepreneur in nearby Edison, New Jersey, have found a least a few neat uses for your discarded bleach bottles and milk jugs.
Their most recent example? A 30,000-pound bridge. When the tourist season begins this spring, park rangers and hikers alike will begin crossing the Mullica River through the Pine Barrens in New Jersey’s Wharton State Forest on a one-lane plank bridge made entirely of plastic.
Rutgers University professors Tom Nosker and Richard Renfree developed the bridge with McLaren Engineering Group and ex-Fortune 500 accountant Jim Kerstein. It is the latest in a series of suprisingly efficient uses they’ve found for old soda bottles, shampoo bottles, and yogurt containers. For several years now Kerstein’s company, Polywood, has been melting and molding recovered plastic into boardwalks, railroad ties, marine pilings, and decking material. But only recently have they developed a mixture hard enough for load-bearing uses. The secret to their new success: Styrofoam.
In Polywood’s Edison warehouse, in a room that smells faintly of burnt kettles, a few workers mix different grades of shredded plastics with polystyrene coffee cups, packing peanuts, and take-out containers. A series of machines heats, cools, and then extrudes the unlikely mixture into two-by-fours, bench planks, and telephone poles. “We’ve found that when you heat these materials up, their polymers wrap around each other and form one extremely durable fiber,” Kerstein says. “We’ve finally hit on a very good stiff blend.”
“I know plastic might not be exactly intuitive,” says Frank Peluso, a section chief in the New Jersey Department of Environmental Protection’s Office of Recycling and Market Development, which funded the bridge. “But the material is structurally sound. The bridge can carry up to thirty-six tons.” Peluso says plastic is also an environmentally sensible choice because lumber used for outdoor functions like bridges, marine pilings, or park benches typically is treated with arsenic and creosote to prevent its decay. “The toxic stuff leaches out into its surroundings, and then the wood rots anyway,” Kerstein says. As it ages, wood also releases carbon dioxide into the environment, whereas plastic lumber does not. “It actually traps carbon, so we’re keeping the air cleaner too,” Renfree says.
Kerstein says that, despite the faint smell, Polywood’s manufacturing process is nontoxic. And the products, which have about a 50-year life span, can themselves be reprocessed. “We actually just run our scrap through machines here,” Kerstein says, patting a bin of plastic shreds, “so we don’t even make any waste.”
Because their durability makes them cost-effective, Polywood’s decking, piling, and boardwalk materials are slowly but surely creeping into parks and onto railroad tracks across the country. Now Kerstein hopes to find new markets for the I-beams. “I bet we could make some really cool stuff with these,” he says, kicking one gently. Even plastic skyscrapers? “The sky’s the limit,” Kerstein grins.
Kerstein says the key to making a successful recycled product is to think broadly. “I think in the beginning people thought, Take an old plastic cup and make a new plastic cup. But that doesn’t work. This is really a better use of the material. It doesn’t pollute when we make it, and we can remake it several times in a row. And it really keeps significant amounts of materials out of the landfills. I mean, the bridge alone is probably 220,000 milk jugs.”