Mitigating Roadway Deicing Salt Runoff: Utilizing Environmental Containment Socks to Sequester Na+ and Cl-

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2022-12-31
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Virginia Tech
Abstract

Roadway deicing salts are applied annually in Virginia and other states impacted by winter weather on a large scale. The United States Environmental Protection Agency (EPA) estimates that the damage caused by road salt costs approximately $5 billion dollars per year in repairs for cars, trucks, roads, and bridges. Improvements have optimized winter maintenance activities, such as better application equipment and technology, utilization of precise weather forecasting, and the implementation of new highway deicing strategies. Nevertheless, additional methods are necessary to combat the detrimental effects caused by deicing practices if the broader ecological consequences of deicing salts are to be adequately addressed. One such method is phytoremediation; however, the plant species that are able to uptake sodium (Na+) and chloride ( Cl- ) ions from the soil do not grow during the winter when road salt application is most frequent. In addition, implementation is limited as phytoremediation cannot be used on impervious surfaces like parking lots where salt can drain freely into sewers and drains. In these situations, environmental containment socks (ECS) are a novel way to filter pavement runoff before it enters a drainage system and ultimately the environment. In this experiment, multiple ECS filled with various Na+ and Cl- binding materials (biofilters) were exposed to a 100mM solution of NaCl to evaluate the potential of this technology at adsorbing salt runoff. The results demonstrate that both Na+ and Cl- can be retained by biofilters and suggests that they can be prevented from entering into the environment. Further studies are needed with ECS in the field to evaluate their potential for recycling sodium and chloride ions for potential reuse.

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