As frequent readers of this column know, the glass container manufacturing industry has a consistent and strong demand for recycled glass at its 45 glass plants across the U.S. In 2015, glass manufacturers purchased 2.4 million tons of recycled glass for remelting into new containers. The purchase of recycled glass is reflected in the average recycled content of bottles and jars nationwide, which has increased since 2008 from 26% to roughly 33% in 2015. At some plants, it reaches as high as 96%. When glass container plants use recycled glass, they experience energy reductions of about 2-3% for every 10% remelted, as well as associated greenhouse gas emissions of approximately 6-8% for every 10% remelted.

The fiber glass industry has a similar need for recycled glass. The North American Insulation Manufacturers Association (NAIMA) is the trade group for the manufacturers of fiber glass and rock and slag wool (mineral wool) insulation. According to a 2014 NAIMA survey, member companies in the U.S. and Canada used more than 2.7 billion lbs of recycled glass and blast furnace slag. In that same year, the data showed U.S. fiber glass facilities used more than 1.7 billion lbs of recycled glass.

As part of the insulation manufacturing process, recycled glass melts at lower temperatures than raw materials alone, greatly reducing energy use at the plants. Energy reduction in the fiber glass industry is complemented by the overall energy savings realized when insulation is used in the built environment. Combined with the glass container industry, the overall demand for recycled glass by these two industries is roughly 3 million tons annually.

Quality and Supply Challenges

Capacity exists at container and fiber glass facilities to greatly increase the amount of recycled glass used in the manufacturing process. However, these industries require certain specifications be met for recycled glass entering their facilities. In fiber glass facilities, while the primary glass colors can be mixed together, (amber, flint and green, known in the fiber glass industry as “mixed bottle cullet”), contaminants such as paper and plastic labels, caps, cork, and other debris need to be removed. In the glass container world, however, colors must be separated (commonly done in the glass processing phase), but paper is less of a contaminant since it burns off in the furnace.

Both industries have encountered challenges securing quality sorted recycled glass, in large part due to the increasing amount of different types of recyclables introduced into residential curbside programs over the past decade. This exacerbates sorting and related contamination challenges, as well as economic challenges. Sorting glass early on in the process at the materials recovery facility (MRF) is one way recycling companies are increasing the yield, while at the same time reducing contamination levels for other recyclable materials.

Partnering on Challenges and Opportunities

In 2015, the GPI reached out to NAIMA leadership to encourage working together on the opportunities and challenges related to obtaining quality recycled glass. As a first start, the GPI has included the 36 fiber glass manufacturing facilities across North America in its online Glass Resource Locator. This tool provides driver routes and directions to and from glass recycling processing facilities and manufacturers. In a single search, waste recovery and recycling businesses can locate two key manufacturers that use recycled glass.

A glass supply chain working group is under way for 2016. In addition to GPI and NAIMA, this initiative brings together a broad spectrum of stakeholders from recycled glass collection companies to on-the-shelf brand owners. Working together on shared goals will help all stakeholders in the supply chain achieve company sustainability and environmental goals, in addition to gaining the environmental and energy benefits provided by the use of recycled glass. 

Any views or opinions expressed in this column are those of the author and do not represent those of Ceramic Industry, its staff, Editorial Advisory Board or BNP Media.