The Call for Quality

Glass recycling systems significantly affect the availability of post-consumer glass for recycling. Regardless of the system, the glass container industry must increasingly advocate for quality recycling programs that will yield post-consumer cullet suitable for bottle-to-bottle use.

Increased quality cullet makes sense for the environment, with glass being among the sustainable packaging options. Composed of abundant natural materials—sand, soda ash and limestone—glass can be recycled again and again without altering its chemical composition. In addition, increasing cullet by 10 percent during the manufacturing process reduces particulates by 8 percent, nitrogen oxide by 4 percent and sulfur oxides by 10 percent. The environment is a growing concern, which accelerates the need for glass recycling and quality cullet.

MAKING THE CASE. Glass containers are easily processed and readily recycled. Unlike some of its competitors, glass can be recycled endlessly without deterioration in its essential qualities. Because glass is chemically inert, its contents benefit from a long shelf life with no risk of cross-contamination.

As a 100 percent and endlessly recyclable container, glass is an ideal environmental product. The Sustainable Packaging Coalition has recognized that, with recycled material in glass containers reaching as high as 90 percent, there is essentially no such thing as "virgin" container glass.

In contrast, packaging made from petrochemical resins can be complicated and expensive to re-make into containers, so when it is recovered from post-consumer use, it is primarily "downcycled." In contrast to recycling, downcycling can be considered the practice of converting a higher-use product into a lower-use product. If a package requires downcycling, it is essentially a single-use container.

Multi-layer, paper-based cartons are even more difficult to recycle and, with a 10 percent recovery rate, can hardly be considered recyclable.

A third material is aluminum, which, despite the prices generally paid for post-consumer metals and the relative ease of recovery, has seen its recycling rate drop in recent years.

DRIVING RECYCLING LEVELS. Using recycled glass to make new bottles benefits glass container manufacturers. Cullet use reduces energy usage, lowers the emissions generated in the production of new bottles and generally extends furnace life and efficiency. Additionally, when cullet cost levels are in line with the cost of batch materials, cullet is an ideal replacement material.

So, with its obvious advantages and a ready market for post-consumer material, why is glass proving increasingly difficult to recover?

The recycling market is largely industry-driven. Glass container and fiberglass insulation companies are motivated to purchase cullet because it replaces batch, improves quality and minimizes energy usage and emission discharges. A notable exception to this is in California, where regulatory and legislative initiatives have a significant impact on cullet availability.

Cullet usage for bottle-to-bottle manufacturing is approximately 35 percent, with rates within the United States and Canada ranging from 15 percent to 80 percent. A significant hurdle is the demand for color-separated materials, as the U.S. market heavily relies on amber and flint (clear) glass and has only a small demand for green, except in California. The primary sources of color-separated glass are the 11 bottle deposit states, which generate the majority of the cullet in the United States, with a similar situation in Canada. Approximately 70 percent of all recycled containers come from these jurisdictions.

The post-consumer cullet available for re-use is approximately 2.4 million tons out of a total sales rate of 10.8 million tons. The largest users are bottle manufacturers, followed by the fiberglass industry and glass bead manufacturers. Another 1.2 million tons has traditionally been marketed in architectural and windshield glass, or flat glass.

Flat glass from the architectural industry, once a significant source of material for fiberglass and bead production, has had significant volume reductions. Manufacturers in that industry have discovered the benefits of recycling their own products and have developed systems to recover it. This has reduced the volume of cullet available for traditional users and has forced them to shift their cullet interests. The trend has put more pressure on supplies of bottle cullet, as fiberglass and bead manufacturers are actively seeking more cullet.

Despite the increasing demand for cullet from the container and insulation industries, usable cullet is becoming scarcer, as curbside recycling programs are under increasing pressure from municipal budget constraints. These constraints have caused cancellation of some programs and the introduction of single-stream recycling. Single-stream recycling, in general, is the commingling of recyclables, such as paper and plastic, glass and aluminum containers, at the curb. Without significant investment in processing the material generated through single-stream collection programs, the glass recovered tends to be less usable for bottle-to-bottle manufacturing.

Single-stream collection systems can tightly compact all recyclables in order to maximize the payload on a truck. These higher compaction rates can crush the glass, potentially diminishing the value of all the recyclables collected, including the glass. The net result is a large volume of fines, up to 40 percent of cullet in some cases, arriving at beneficiators. Cameras used in optical sorting systems cannot see the fines measuring less than ¼ inch, so much glass is wasted.

Single-stream programs continue to grow rapidly in the United States and Canada, in part because of the objective of cost savings to municipalities. These programs have also grown in part because of state mandates to increase the volume of material collected.

Despite the cost savings in transportation, single-stream recycling is not always favored by downstream consumers of recyclable commodities, whether it’s the paper, plastics or glass industries. This system can benefit large, vertically integrated waste enterprises with landfills in their portfolios. But when not well designed, single-stream systems can potentially increase the volume of recyclables going to landfill, losing the purpose and focus of recycling.

BENEFICIATING INTO CULLET. Where deposit glass is available, a simple cleaning and crushing system can ensure full recovery of the material. It is inexpensive and generates high-quality, color-separated cullet.

For dual- or single-stream systems, the current sorting technology used to make mixed cullet useful employs cameras, which typically see down to ¼ inch, and high-speed computers. Improvements are being made that will enable the sorting systems to see and process smaller pieces of glass, but not necessarily at high production rates. Provided the speed of production is geared correctly, the process delivers good quality glass for manufacturers.

The growth of single-stream recycling can create many problems for glass, especially when the sorting methods deployed are not up to the task of sufficiently sorting commingled materials. Further, the performance of some material recovery facilities has reduced cullet availability and resulted in inconsistent quality.

The substantial demand for all three colors of cullet increases the complexity and cost of processing glass. This has put further pressure on cullet supply because color sorting is largely required for glass container plant usage. The net result is that recyclers increasingly view usage for road base and fiberglass as attractive options.

RECYCLING OPTIONS. Bottle deposit return programs are one option for the glass container industry to improve usable quantities of post-consumer glass. These deposit programs provide excellent source-separated material and, therefore, higher cullet quality. An additional bonus for jurisdictions with deposits is that unredeemed bottles provide surplus revenues that, if used appropriately, can pay for the deposit programs and be reinvested to improve container recycling.

One method of curbside collection that was relatively successful for many years was the dual-stream system, which separated fibers (newsprint) from most beverage containers. The net result was systems that generated material of reasonable quality at lower volume—and lower costs to brand owners—than deposit return systems.

However, some single-stream programs have not been successful in producing substantial volumes of material for bottle-to-bottle manufacturing. Such systems can be successful in recovering cullet if there is a proper investment in downstream material and color separation technology.

Regardless of the collection program used, the glass industry needs good cullet. For every 10 percent of cullet used in the manufacture of glass containers, there is a 2.5 percent energy savings. Such energy savings also bring environmentally beneficial emissions reductions at the source and lower energy production costs upstream. Using cullet in bottle-to-bottle applications also helps reduce landfill volume and unnecessary downcyling.

ADVOCATING FOR RECYCLING. The glass industry’s arguments supporting the sustainability and, thus, the superiority of glass containers are clearly underpinned by the full employment of post-consumer cullet.

The glass container industry should not allow competing materials to "occupy the field" as determinations are made regarding the shape of recycling systems. As evidenced by experience, when it comes to recycling, "more is not always better." The demand for quality recycling needs to be the new mantra of the glass container manufacturing industry.