Date: Jan 06, 2012 Author: John Caulfield Source: Builder (
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Three million tons of glass were recycled in 2009, four times more than in 1980, according to the EPA's latest estimates. But that's only about one-quarter of the glass that ends up in the country's solid-waste stream. And of the total that gets recycled, 90 percent is used to make containers, with the rest becoming part of road aggregate, kitchen tiles, countertops, and wall insulation.
"Current recycling technology is very inefficient," explains Grant Marchelli, a 29-year-old graduate engineering student at the University of Washington. "Only the purest, non-colored glass is used for containers," which eliminates much of what's available.
Marchelli and Renuka Prabhaker, 37, a fellow graduate student, think they've come up with a way to recycle more glass, regardless of color or contaminants. Their nascent Seattle-based company Envitrum (Latin for "out of glass") has developed a manufacturing process that converts crushed 100 percent post-consumer glass into a material called VitroBricks. The process isn't that different from the way traditional masonry bricks are made, except that the heat needed to fire the form-pressed glass is about 60 percent less than for masonry, although Prabhaker notes that the heating schedule for VitroBricks could have as many as 10 temperature phases.
VitroBricks is one of those "if at first you don't succeed …" discoveries. The duo had experimented unsuccessfully with "sintering," a technique for fusing powderized materials. Turning crushed glass into 3D printing didn't pan out, either, according to Sustainable Industries magazine. But in 2010 Envitrum's manufacturing process won the $10,000 grand prize from the University of Washington's Environmental Innovation Challenge. And Waste Management reportedly is paying Envitrum to take a portion of the mixed-color glass it collects.
As they work toward their Ph.D.s, Prabhaker and Marchelli have received Small Business Research funding from the National Science Foundation. They envision their products being used for what Prabhaker calls "rainscreen" applications that envelop residences and commercial buildings. While glass additives tend to make building products more brittle, Envitrum's process is one of the first to use glass as the main ingredient without compromising the strength of the finished product. Prabhaker doubts, though, that Envitrum's products will ever replace structural materials such as concrete blocks.
In October, the company had a patent pending, and its principals were networking to raise money and establish procurement and sales relationships. The partners are also talking with architectural firms—one of which, Seattle-based Perkins+Will, is on Envitrum's advisory board—about installing demonstration pieces of VitroBricks. They'd like to have an actual product ready within the next 12 months, with the goal of licensing the process.
