PLANNING, DESIGN AND OPERATION OF A SALT TRUCK WASHING WASTEWATER REUSE FACILITY

The paper describes the planning, design and operation experiences of a facility using wastewater generated from a salt truck washing operation to make a salt brine for antiicing. The planning phase included an evaluation of salt truck washing wastewater handling alternatives including reverse osmosis, vacuum and atmospheric evaporation, disposal by contract hauling and reuse. Reusing the wastewater for anti-icing was selected due to its cost-effectiveness and other benefits.The wastewater reuse facility design included grit and oil-water separators, a pump station and wastewater storage tank, a feed pump and brine production system, four salt brine storage tanks and four transfer pumps. Following pretreatment in the grit and oilwater separators, the wastewater was pumped into the brine production system where salt was added to give the brine a sodium chloride content of 23.7%. At this concentration, the brine has a freezing temperature of −21°C, making it suitable as an anti-icing agent.The facility was completed in November 2001, allowing the brine generated from the reuse system to be applied to the Borman Expressway near Gary, Ind. last winter. The brine prevented frost and ice from building up on roads and bridges, resulting in a substantial reduction in traffic accidents.