Physical and chemical characterization of recycled glass sand for environmental restoration

Abstract Introduction We rely on coastal resources for food, water, and energy. However, over 75% of U.S. coastlines are eroding. Concurrently, the U.S. recycles less glass than other developed countries, landfilling hundreds of millions of tons every year. Recycled glass sand has many potential benefits over natural sand for combatting land loss; for example, it can be produced with controlled particle size to better resist erosion, making it an excellent—and underutilized—material for environmental restoration. Objectives This research compares the physical and chemical properties of recycled glass sand to natural sands (beach and dredge) from the U.S. Gulf Coast to assess environmental safety. Methods Particle size distribution, angularity, particle and bulk density, compaction, and permeability were evaluated using standard methods. Elemental composition and leaching were analyzed using x‐ray fluorescence and toxicity characteristic leaching procedure (TCLP), respectively. Results Recycled glass sand is not “sharp,” although it is less well‐rounded than natural sand. Porosity, compaction, and water permeability depend on particle size, and glass sand can be size‐separated to match or complement natural sand. Recycled glass sand is mostly silica. Additional elements used in glass processing are present at acceptable levels, and no leaching of harmful elements is detectable by TCLP. Thermally decomposable residues (e.g. label and adhesive) reliably comprised less than 1% of the material. Conclusions The characteristics of recycled glass sand make it a good resource for environmental restoration.