After 4 years, Anchorage is still working to make glass recycling worth the effort

In a corner of the yard at Central Recycling Services lies two piles of glass.

One is a mountain of empty bottles, with labels mostly left intact: Prego pasta sauce, Synergy kombucha, Martinelli's sparkling cider and super-sized containers of Kirkland Signature vodka.

The other looks like a pile of cream-colored sand, tinged slightly green. Look closer and it's clear that the tiny globes aren't sand at all, but brightly colored chunks of ground-up glass.

This is the end product for glass recycling in Anchorage, one of the city's most popular — and controversial — types of recycling.

[Related: Glass recycling starts up again in Anchorage]

Glass recycling has been available off and on in the city for more than two decades. The economics of glass recycling make it difficult to sustain here.

But the raw material needed to make glass in the first place — sand, essentially — is cheap and plentiful. There's less incentive to purchase the recycled product, making it hard for companies processing recycled glass to make a profit.

Glass usually ends up getting recycled by being ground down into small pieces — aggregate — that can be used for everything from traction to construction fill.

When Anchorage had glass recycling before, one company tried to use the glass to make sand for sandblasting ships. Another began selling crushed glass to the Alaska Railroad for traction. Neither found significant markets in Alaska and glass collection last ceased in 2008.

Since restarting in late 2012, about 1,200 tons of glass has been collected each year, according to Travis Smith, recycling services coordinator for the municipality of Anchorage. That annual total is the equivalent of about two days worth of trash being diverted from the Anchorage Regional Landfill.

The average amount of glass collected for recycling each year has been about the same over the last four years as it was before the program was halted, said Donna Mears, environmental engineer with Central Recycling Services and a former municipal recycling coordinator.

The mountains of glass piling up at the recycling services storage yard works out to several month's worth of collection, Mears said. It looks impressive, but it only breaks down into a small portion of crushed material.

"It's mostly air," she said of the piles of bottles.

This year, Central Recycling Services sold 300 tons of crushed material for construction projects. The year before it sold 800, about three-quarters of the total amount of glass received that year. Mears said the amount they sell depends on how much contractors order. Overall it's a small percentage of the recycling the company collects each year, she said.

Part of the comeback for glass in 2012 was that state and municipal specifications changed to allow glass aggregate to be a partial component in backfill. It can be used as 100 percent fill for sewer and water pipe construction.

But Mears said getting contractors to order glass has been slow to catch on. While changing the specifications has helped, engineers and contractors are not required to use it. She said some have been hesitant to use the new material.

The company is hoping to expand markets for recycled glass by adding a screen that sifts out smaller bits of glass — less than 1/4 inch in size — that could be used as traction in parking lots and other walkways, just like sand. Mears said the recycling services yard already uses the aggregate for traction.

Glass is only recycled in three places in Anchorage and it's prohibited in curbside recycling pickup. That's because all the recycling collected in the bins is bundled and sent to Washington state for sorting, according to Smith, the recycling services coordinator for the municipality.

Adding glass would add to the weight of what's being shipped, making it more costly and creating a lower-value product, Smith said.

But finding more markets for the recycled glass could mean an increase in glass collection — maybe curbside pickup at some point.

"At the moment the demand we're meeting is the demand for residents to recycle glass and what we're wanting to happen is for the demand of the end product to grow," she said. "And when that grows, we can start targeting it much more as reducing the waste stream. We're doing some, but there's more out there."