Strategies to Mitigate Salt Runoff from Salt Storage and Salt Truck Maintenance Facilities

Abstract

Mitigating salt runoff at salt storage and salt truck maintenance facilities has become a concern for many state departments of transportation (DOTs), since their storm water discharge is found to pollute the environment. The use of nonstructural and structural best management practices (BMPs) are required to minimize the generation of liquid waste containing salt and to minimize the potential hazard caused by salt runoff. The regulatory requirements mandate appropriate disposal of treated salt runoff, which has instigated the need to use wash water to make salt-brine for salt prewetting and anti-icing applications. This paper discusses a novel approach to collect and treat the liquid waste containing salt based on an approach similar to the wastewater management practices used in vehicle and equipment washing facilities. Collected wastewater will be first made to flow through an oil–grit separator to remove hydrocarbons and organic material, then through an underground sediment–sand filter to remove sediments. Sediments and oil–grit free wastewater will be stored in a fiberglass underground holding tank, until it is reused during the next winter storm. The salt–brine used for prewetting salts and for anti-icing is the eutectic solution with 23% salt, by weight. Salt solutions with low concentrations can be used as the base solution for making salt–brine, though it has to be intermittently stirred to prevent bad odor. The proposed measures may reap significant cost-savings, which otherwise would incur in treating wastewater prior to disposal.