Material Flows and Energy Analysis of Glass Containers Discarded in New Jersey, USA

The use of glass cullet (crushed recycled glass containers) as aggregate in construction projects and landfills has increased rapidly even though the use of cullet as feedstock in new glass container and fiberglass production is energetically more sound. The effect of increased use of cullet as aggregate has not yet been thoroughly assessed. The objectives of this study were to model and quantify glass container flows across New Jersey and the associated life cycle energy consumption, and then compare life cycle energy consumption for two different recycling scenarios and three different end‐use/disposal scenarios. The results of a material flow analysis showed that in 2008 only about 11% of the glass containers consumed in New Jersey were used as glass container or fiberglass feedstock, while five times more were used as construction aggregate. However, a lower system energy requirement can be achieved by increased use of cullet as container feedstock compared to construction aggregate, even when the cullet is transported 1,600 miles to a glass container manufacturer. Based on the uncertainty analysis, there is about an 80% probability for the scenario with increased use as container feedstock to have a lower system energy requirement when compared with all other scenarios. To achieve increased use of cullet as glass container feedstock in New Jersey, the quality of the cullet must be improved.