October 2, 2009 in City

City using crushed glass for road-building

Hillyard project first to use costly-to-ship commodity

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Colin Mulvany photo

Jared DePue, with Inland Asphalt and Paving, lays asphalt on North Market Street over roadbed containing recycled glass.
(Full-size photo)

Until recently, empty bottles and jars had to be hauled hundreds of miles from Spokane to be transformed into recycled products.

Glass collected at the curb was trucked to Calgary, Alberta, and then Edmonton, where it was turned into fiberglass. When that market dried up, Spokane’s glass was shipped to Portland, where a recycling company prepared it for a train trip to California to turn it into wine bottles.

But concerns over the financial and environmental costs of shipping glass to faraway locations led the city to look for new possibilities. Now local glass is reused locally – in road construction.

Recycling companies in Spokane that handle curbside collections from the city and Waste Management began taking glass to city property in Colbert, Wash., last summer, where it was collected until crushed for roadbeds.

The city’s first project using recycled glass began over the summer in Hillyard. The city is using 1,500 tons of crushed glass in the 1.25-mile reconstruction of Market Street. The glass was combined with crushed rock to create a 9-inch-thick bed on which an 8-inch layer of asphalt is laid, said Ken Brown, the city’s principal construction engineer. Crushed glass makes up between 12 percent and 15 percent of the roadbed.

Inland Asphalt is charging the city $293,000 to build the roadbed with the glass. It estimated the glass added $30,000 to the cost.

Officials say they’re still crunching numbers to determine if the money saved on shipping will cover the increased cost of road construction. But even if it doesn’t now, they say, working with recycled glass will become cheaper as the city and contractors gain experience.

Scott Windsor, who leads the city’s solid waste department, said the program has cut glass-recycling costs because of greatly reduced transportation costs. Before, the city paid local recycling companies $45 a ton to handle glass plus as much as $30 a ton to truck it from Spokane. The $45 charge still applies, but transportation costs are perhaps just a few dollars a ton, he said.

Even before the switch, Windsor said, recycling was cheaper than paying $98 a ton to take the glass to a landfill in south-central Washington.

Spokane has an extra incentive to recycle glass: Most trash in Spokane County is burned at the Waste-to-Energy Plant. Glass doesn’t burn. Rather than creating energy that can be sold, it uses energy as it is melted. Then it ends up being sent to a landfill anyway, with the rest of the ash created at the plant.

In 2008, about 42,600 tons of glass was collected for recycling by the city, Waste Management, which does most curbside collection outside the city, and the Spokane Regional Solid Waste System.

James E. Shelby, a glass science professor at Alfred University in western New York, said the best use for used bottles is generally to recycle them into bottles. That’s because making glass bottles out of old bottles uses significantly less energy and creates less carbon dioxide than using raw materials.

But getting the glass ready to recycle often is cost-prohibitive and creates environmental concerns about fuel usage – especially for communities like Spokane that are far from companies that use recycled glass. That problem has caused many communities to abandon curbside glass recycling. Kootenai County began sending glass to a landfill in 2008.

Shelby said using glass in roadbed is a good alternative: “If it gets broken up, it acts just like sand.”

And glass carries no environmental concerns. “What comes out is pretty innocuous stuff,” Shelby said. “That kind of glass just doesn’t have any toxins.”

Five comments on this story so far. Add yours!

• 

  CalJones on October 02 at 6:40 a.m.

  So basically - Tax Payers be damned! The city is screwing over taxpayers so that they can feel good about themselves for recycling locally. Recycling should be done by the private market, when the market sees fit, not forced on us by the city.

• 

  MrNatural on October 02 at 10:14 a.m.

  This is a great way for the government to support the local economy and to save taxpayers money. By recycling and road building they use a safe inert material; hereby saving money and the environment. I find it confounding how privatism demonizes “government” when we “are” the government and this benefits all peoples instead of the greed of one.

• 

  wyoboy on October 02 at 11:38 a.m.

  Another option is to use it in the cover on the “dead animal pit” at the land fills. The skunks, foxes, coyotes and badgers do not like to dig in the dirt when it has glass in it.

• 

  Lonny on October 02 at 12:33 p.m.

  Ahem… since when does the “Waste to Energy” plant actually generate more electricity than it uses? If it does, this is the first I have heard about it.

  You can’t “create energy to be sold” unless it is excess energy, over and above what your plant needs to operate. To the best of my knowledge, Spokane’s trash burner does not create, and has not created, excess energy. It uses more than it generates.

• 

  jonathanb on October 02 at 3:42 p.m.

  Lonny,

  The city’s trash incinerator, the Waste-to-Energy plant, does generate more power than it uses. Damon Taam, the system contract manager for the Spokane Regional Solid Waste System, said that in 2007, the plant produced 170,533 megawatt hours worth of electricity. Of that, 141,747 megawatt hours were sold to Puget Power, earning the plant about $12 million. The difference between the total amount produced and the energy sold to Puget Power is what was used to power the plant.

  Jonathan