Multiple uses for recycled glass found in Minnesota
Glass supply, once contamination has been eliminated, is available in abundance and the state of Minnesota has creatively found alternatives to landfilling this valuable resource.
Glass containers that are brown, green and clear are commonly recycled in Minnesota. The majority of this glass is recycled back into new containers to package food and beverages. However, many companies and counties are exploring alternative recycling options for post-consumer glass.
Glass as an Abrasive
Success Story: Winona ORC Industries (WORC)
WORC formed a partnership with the Southeast Minnesota Recyclers Exchange (SEMREX), an alliance of local public and private recyclers that operates a program to assist the region in marketing its recyclables to end-users. In 1994, WORC received a grant from the OEA to demonstrate that they could locally manufacture garden pavers made from recycled glass.
Their manufacturing method is an internationally recognized ground-glass/fire-kiln process — the only one like it in the world. Much like works of art, the products made with this process are unique; background hues vary with the mixing of colored glass. The non-porous glass is strong and durable, does not absorb water, and can withstand extreme heat and cold. Independent testing has proven them to be virtually chip and crack-free under hundreds, or even thousands of pounds of stress.
Glass as Road Aggregate
Success Story: Ramsey County
Success Story: Otter Tail County
In 1996, the county recycling program began stockpiling glass containers collected for recycling. In 1997, because the glass was dedicated to use in highway construction, the glass-recycling program was expanded to include non-container glass, including dishes, window glass and glass cookware.
The project to re-construct a four-mile section of Highway 74 began in September 1998. Bid specifications required the contractor to include a 10% blend of recycled glass (by weight) in the aggregate used in the road base. The County Solid Waste Administrator, Mike Hanan, and the County Engineer, Rick West, worked closely with the contractor to ensure that the material used in the base course was clean and of high quality. Engineers determined that the glass could be crushed as it was blended with gravel. The finished product was a MnDOT Class 5 aggregate base with a one-inch maximum particle size. Some salvaged asphalt pavement was also included in the blend.
This mixture performed well during construction, with no need for special equipment. The county has found that this use is an excellent way to recycle glass locally, avoiding the high transportation costs and color separation of the glass required for recycling back into container glass. “We will do these kinds of things (aggregate amendment) until the market says that trucking glass to be used for new glass makes sense,” says West.