Non-hazardous industrial waste in the United States: 100 Million tonnes of recoverable resources

Despite the large volume of non-hazardous industrial waste (NHIW) being generated globally, systematic NHIW reuse policies are lagging, largely owing to piecemeal understanding of generation volumes, locations, chemical constituents, and future trends. Herein, we demonstrate how to estimate the mineral and energy flows embedded in the 200-300 million tonnes of NHIW in the United States using information from process engineering and economic projections. We estimate that the minerals contained in NHIW are on the order of 100 million tonnes and with electricity potential lectricity at 200 billion kWh annually from 1990 to 2016. Both are expected to increase by roughly 50% from 2017 to 2050. The electricity potential and bulk mineral contents (e.g., CaO and SiO2) are modest compared to the total level of consumption of these resources (<3%), but there are county-level hotspots along the west coast with opporunities possibly large enough to yield significant material benefits at the local scale. Two lower-volume minerals, phosphorus and titanium, are noteworthy from a material substitution standpoint. They are estimated at 0.5-2.0 million tonnes in NHIW annually, which is 10-20% of current consumption and up to 50-80% in hotspot states. Although there are difficulties in cross-national generalization, we anticipate that the workflow steps themselves would be transferrable to other countries to be able to yield the chemical, locational and temporal information needed to inform the design of region-specific NHIW reuse programs and the development of NHIW valorization technologies.