Truth About Glass Recycling

Green recyclable glass bottles

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Before you deposit the next beer or wine bottle into your blue bin, here are a few things to know about recycling your favorite sand-based product:

  1. It has the quickest turnaround of any curbside product, back on store shelves in as little as 30 days
  2. There’s a strong market for recycled glass, and the demand is not currently met
  3. A good portion of glass that you place in your recycling bin is not actually recycled

What is Downcycling?

According to O-I Global, the leading glass manufacturer in North America, about 1.6 million tons of glass are downcycled, translating to almost 40 percent of the 4.2 million tons collected annually for recycling. Furthermore, this 4.2 million tons represents only 25 percent of total glass manufactured, as shown in the chart below.

Let’s start by explaining what happens to all this glass that isn’t reprocessed into new containers. To do this, we need to understand the concept of downcycling.

Downcycling is the process by which materials are recycled into a product of lesser-quality. An example for glass containers would be fiberglass or using it as an additive in concrete or ceramic tiles. The decision to downcycle glass is usually based on the quality of material, but who makes that call?

“This is most often the decision of the Material Recovery Facility (MRF),” says Paul Smith, O-I’s Global Sourcing Manager of Cullet. “Aggregate use of glass is important but limited in application. The recycling rate through MRFs could improve.”

One of the issues is the popularity of single-stream recycling, where all materials are collected in one bin. The materials are then separated at the MRF using a system of magnets, eddy currents and other machines, with glass being separated based on its weight.

During this process, glass tends to be crushed, which lowers the quality and increases the chances it will be downcycled. Smith says crushing can be a negative because large sizes are preferred when it comes to reprocessing glass into new containers.

O-I Cullet Recycling

Incentivizing Participation

One way to offset the loss of glass product from downcycling is for consumers to recycle more glass in the first place. When referring to municipal solid waste, the EPA reported a 28 percent glass recycling rate in 2007. This would rank glass containers below steel cans (64 percent), paper (55 percent), aluminum cans (49 percent) and plastic soft drink bottles (36.6 percent) when it comes to container recycling.

Every ton of glass that is recycled results in one ton of raw materials saved to process new glass, including: 1,300 pounds of sand, 410 pounds of soda ash and 380 pounds of limestone. Photo:

Every ton of glass that is recycled results in one ton of raw materials saved to process new glass, including: 1,300 pounds of sand, 410 pounds of soda ash and 380 pounds of limestone. Photo:

But in California, nearly 71 percent of glass was recycled in 2007, with an increase to 80 percent last year. The Glass Packaging Institute attributes much of the difference to the fact that California has a bottle deposit law.

“The greatest participation of glass recycling tends to come from deposit programs,” adds Smith in reference to the 11 states that incentivize recycling beverage containers. “There are several tiers of glass recycling, but this is the highest quality.”

In addition to the financial incentive for consumers to recycle containers in these states, part of the deposit goes to funding collection facilities. This means better access to recycling drop-offs for glass in these states.

Spread the Word

While it’s possible to manufacture glass containers with over 90 percent recycled content, the lack of supply makes this difficult.

“Sometimes there is a perception that there’s no market for recycled glass, and that’s not the case,” says Smith. “We need to create awareness of this, and consumers can do their part by finding out what is happening with recyclables.”

It’s also import to know what glass is accepted. Putting in a color of glass that is not accepted by your program, or treated glass, such as windows and mirrors, leads to contamination issues that reduces the value of your entire batch.

For its part, O-I is becoming aggressive in developing new technologies and pursuing contracts that will increase glass collection. The company has been able to increase its glass recycling rate by almost 7 percent in the past three years.

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Trey Granger

Trey Granger is a former senior waste stream analyst for Earth911.
Trey Granger

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