PROFILES IN GARBAGE: Glass Containers

Glass containers are made from sand, limestone, soda ash, cullet (crushed bottles) and various additives, including those used to “color” brown, green or blue bottles.

Clear (also known as flint) bottles may equal as much as half of the glass bottles produced in the United States, followed closely by brown bottles. Most of the remainder are green with a very small amount of blue or other colors. Half of the green bottles used in the United States are imported wine and beer bottles.

In 2000, approximately 36 billion glass containers, weighing approximately 10.4 million tons, were manufactured in the United States. Eighty percent were narrow neck containers, used primarily for beverages. The remainder were wide mouth bottles used for food products. Another 650,000 tons of glass bottles, mostly used for beer and wine products, were imported. Glass bottles use in the United States increased by 4.9 million tons between 1960 and 1999, for a 79 percent increase. However, the glass container market share of municipal solid waste (MSW) declined in the same time period by 31 percent as lighter weight aluminum and plastic containers replaced glass bottles.

Other glass products include flat glass such as windows, fiberglass insulation and glassware. These products use different manufacturing processes and different additives than container glass.

This profile does not cover noncontainer glass.

Glass Containers Municipal Solid Waste Facts:

Generated:

  • 11.05 million tons or 4.8% by weight.*
  • 81 pounds per person per year.*
  • The average glass bottle weighs 8 oz.
  • 82% of glass bottles are generated from homes; 18% from businesses.
  • Recycled:

  • 2.94 million tons for a 26.6% recycling rate.*
  • Industry data shows a 35% recycling rate in 1999. (This figure includes refillables at a trippage rate of 8 times per bottle.)
  • 10 states require deposits on glass beverage containers.
  • Recycled Content:

  • 26% U.S.-produced bottles.
  • A glass bottle can have up to 70% recycled content.
  • Composted:

  • Glass does not compost.
  • Incinerated or Landfilled:

  • 8.1 million tons or 4.9% of discarded MSW by weight.*
  • Glass is inert in landfills.
  • Glass is noncombustible and generally forms a slag.
  • Landfill Volume:

  • 5.5 million cubic yards or 1.3% of landfilled MSW in 1997.
  • Density:

  • Landfilled glass bottles weigh 2,800 pounds per cubic yard.
  • Loose glass bottles have a density of 600 pounds per cubic yard.
  • Crushed bottles have a density of 1,000 pounds to 2,000 pounds per cubic yard.
  • Source Reduction:

    Like all packaging industries, the glass industry always is looking for ways to decrease the weight of its products. Nonreturnable glass bottles were reduced in weight by 44% between 1972 to 1987 and have achieved additional reductions since then.

    A new beer bottle using 20% less glass now is available.

    EPA estimates that source reduction measures such as end-users switching to lighter weight plastic, metal packages or glass bottles becoming lighter in weight, resulted in 5 million fewer tons of glass in the waste stream in 1999.

    Recycling Markets:

    The glass container industry is the primary market for cullet, using more than 80% of the glass that was recycled.

    Fiberglass products are the second largest market for cullet. Other secondary markets include abrasives used in sand-blasting; aggregate substitutes used in road construction including “glasphalt,” glass beads for reflective paint; fiberglass; filler in storm drain and French drain systems; frictionators used for lighting matches; glass foam and fluxes; and other additives.

    A minimal amount of glass is exported for recycling.

    End-Market Specifications:

    Glass containers fall under Institute of Scrap Recycling Industries (ISRI) Guidelines for Glass Cullet: GC-01, with color-specific specifications for unprocessed and processed (furnace ready) container glass cullet.

    Unprocessed cullet should be free of excess moisture and may not be pulverized. Prohibited materials include noncontainer glass, metals, rocks and ceramic closures. Unprocessed clear cullet must be at least 95% clear glass; brown cullet must be at least 90% brown glass; and green cullet must be at least 90% green glass. After processing, the cullet must be suitable for glass container production.

    Glass bottles often break when collected in curbside programs. Breakage solutions include installation of interior baffles or nets in the collection trucks, special glass-only truck compartments, and limiting the number of times glass is transferred after collection before final processing.

    Recycling Cost and Value:

  • Collection costs range from $54 to $77 per ton.
  • Processing costs range from: $37 to $105 (clear glass)$70 to $149 (brown glass)$58 to $134 (green glass)$29 to $76 (mixed color glass)
  • Chaz Miller is director of state programs for the Environmental Industry Associations, Washington, D.C. E-mail the author at: [email protected].

    Sources:

    Current Industrial Reports, U.S. Census Bureau, Washington, D.C. Website: www.census.gov.

    Glass Packaging Institute, Washington, D.C. Website: www.gpi.org

    “Measurement Standards and Reporting Guidelines,” National Recycling Coalition, Alexandria, Va. Website: www.nrc-recycle.org

    Municipal Solid Waste In the United States: 1999 Facts and Figures, U.S. EPA, 2001. Website: www.epa.gov.osw

    National Solid Wastes Management Association's Waste Recyclers Council, Washington, D.C., Processing and Collection Cost Studies

    Rhode Island Dept. Of Environmental Management, 1990.

    Scrap Specifications Circular 1997, Institute of Scrap Recycling Industries, Washington, D.C. Website: www.isri.org

    *1999 EPA estimates.