Over the past two decades, single-stream recycling collection (all recyclables in one bin) has taken root in many communities. With that growth has come challenges to securing high-quality recycled glass to make new glass containers. The benefits of using recycled glass are considerable, including reduced energy use and related costs at the manufacturing facility, along with the reduction of associated greenhouse gas emissions.

Sorting Recycled Glass

Challenges associated with single-stream recycling programs include variability in how collected materials are processed to prepare them for an end market. The addition over time of more types of recyclables in the single-stream collection mix has also multiplied that challenge—for glass recovery and other materials.

When it comes to sorting out recycled glass containers, the processing systems at many materials recovery facilities (MRFs) do not support maintaining the integrity of the glass so that it is suitable for closed-loop recycling. Much of the recycled glass goes to secondary uses or landfills, rather than back to glass container manufacturers for making new food and beverage bottles.

Industry Collaboration

While glass container manufacturers have maintained persistent efforts to work with suppliers of recycled glass, or “glass processors,” to improve the supply of quality recycled glass, they have not specifically targeted these same efforts with MRF operators. Recently, however, glass container manufacturers, through the Glass Packaging Institute (GPI), have opened a dialogue with members of the National Waste and Recycling Association (NW&RA). This trade organization counts many large and small MRF companies among its membership.

The goal is to better understand the fundamentals of the recycling stream and how recyclable materials from single-stream programs are being handled in MRF systems. This includes how all recyclables are collected, processed and sorted, as well as end-market opportunities for recycled glass containers. As the dialogue has progressed, participating MRFs have expressed a desire to learn more about single-stream recycling collection programs around the U.S. that are having success recovering recycled glass to produce a high-quality end product.

Best Practices for Glass Recovery

To help capture processing and sorting methods at MRFs that are proving best for glass containers, GPI is in the process of finalizing a commissioned report that will analyze single-stream recycling programs with demonstrated success in recovering glass for bottle-to-bottle recycling. This includes the basic building blocks of MRF equipment and technical practices. It will also show data on secondary markets, or non-container uses for recycled glass that do not meet glass container manufacturer specifications.

While the analysis remains a work in progress, initial findings have identified specific sorting equipment at MRFs that aid in a successful glass recovery process. The report is also yielding substantial information on secondary markets, as NW&RA members look to more immediately move contaminated recycled glass unsuitable for the container market. Secondary markets include beach supplement, glassphalt for roads and highways, and sand substitution for filtration and related products.

Upon completion, the analysis will provide assistance to all recycling stakeholders on the most beneficial ways to recycle glass, as well as guidance on effective equipment, technical information, and best practices for producing recycled glass suitable for the glass container market. 

 For more information, visit www.GPI.org. 

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.