Americans toss out approximately 10 million metric tons of glass each year. Most of that ends up in the solid waste stream even though glass is 100 percent recyclable. According to the Glass Manufacturing Industry Council, glass has an unlimited life and can be melted and recycled endlessly without losing quality to new glass products.
Many curbside recycling programs have banned glass from recycling bins because it contaminates other recyclable materials, creates problems with machinery at processing plants, and poses risks to works.
Still, the glass container industry values recycled glass for its many benefits. Benefits. The industry mixes cullet, granulated material made by smashing jars and bottles from recycling plants, sand, limestone, and other raw materials used to make molten glass to manufacture new jars and bottles.
Cullet allows the glass industry to reduce the need for raw materials. Cullet also decreases the amount of energy needed to keep furnaces hot enough to produce molten glass, reducing operating costs. The recycled cullet also improves glass quality by limiting crystals and streaks due to incomplete mixtures of raw materials. And adding cullet reduces greenhouse gas emission from manufacturing. Carbonates from limestone release CO2 when they melt with other materials. Scientists estimate that using cullet in manufacturing glass lowers emissions by about 5 percent.
But producing quality, furnace-ready cullet requires more effort on the public accustomed to the ease of single-stream recycling and more automated and manual sorting and equipment upgrades at recycling plants. More public outreach and education on proper recycling practices seem to keep the recycled glass on its upward swing. Multi-stream recycling, which requires people to sort and place paper, plastic, aluminum, and glass in separate collection containers, is one solution. Glass from multi-stream systems is much cleaner than glass recovered from single-stream recycling. About 40 percent of the glass from the single-stream collection is recycled into new products, while 90 percent of the glass from multi-stream systems is recovered and reused. But municipalities consider single-stream collection an improved service and are unlikely to welcome a return to multi-stream.
Another alternative is to combine education with glass collection sites. Salt Lake City, Utah, had had great success with a collection site that combines the community’s belief in the value of recycling with pride in the natural environment and appreciation of public art. Momentum Recycling teamed up with city officials and hired a local artist to paint a mural of the state’s red rock arches on a dumpster in a city park used as a glass recycling collection site. Last year, residents rose to the occasion and kept 1,550 tons of glass from the city landfill.
The recycling industry should consider partnering with the public to keep recycling on the rebound with glass.