AASHTO Journal, 31 October 2014
Salt shed with runoff pond in background.
Photos courtesy VDOT.
Virginia Department of Transportation is expanding the use of saltwater brine mixtures to help prepare roads when a winter storm is approaching, and plans a pilot test in one area of the state to use brine again after a snowfall in place of road plowing.
The state’s brine focus could have several benefits – cutting the use of direct rock salt applications at a time of high costs and tight supplies for that commodity (see related coverage in Top Stories), and cutting environmental disposal costs of brine runoff that VDOT already collects into holding ponds where it stores salt.
The agency says it wants to sharply increase the amount of brine it harvests from those ponds.
Those plans emerged as VDOT said it budgeted $145.5 million for snow removal over the 2014-2015 winter, out of an overall fiscal 2015 maintenance budget of about $1.5 billion.
Last year it set aside $157 million for snow removal heading into the 2013-14 snow season, but ended up spending $350 million by the time the long, harsh winter finally ended.
Like many states, Virginia has been capturing brine runoff from its salt storage and loading facilities to prevent salt buildup in waterways, directing it either into underground tanks or holding ponds. Then it pays contractors for offsite disposal that meets environmental requirements.
But the agency said in recent years “VDOT has relied more and more on applying brine to roads in areas where feasible before winter storms. This is because it can prevent frozen precipitation from bonding to the pavement, and it’s more environmentally friendly than salt.”
VDOT has already recycled runoff from most of its Richmond district salt facilities to use as road applications, as part of a multiyear pilot project. Last year, that district used about 550,000 gallons of brine that mostly came out of those holding ponds.
Now, the agency aims to increase locations where it can recycle runoff into anti-icing applications. It said “in-house research has determined that VDOT could reduce the volume of water requiring disposal by at least 50 percent.”
In a new pilot that can also help reduce costs, its Northern Virginia District will only apply a brine mix in part of Chantilly, without additional hard salt, to “determine if this is a viable alternative to applying salt after plowing.”
VDOT’s anti-icing road treatments include liquid calcium chloride as well as brine. For the winter ahead, it has stockpiled 564,405 gallons of the calcium chloride and 1.1 million gallons of brine, plus 366,678 tons of salt, and said it will rebuild stocks as needed in coming months.
