What great timing! Knoxville's Public Service Division had a new Salt Brining Mixing and Deployment System, with tank trailers built and delivery vehicles modified by the Fleet Services division, all ready to go in time for the series of "snow events" that began Jan. 5. Here's what's involved, according to the city:
• The perfect solution of brine is a 20-23 percent concentration of salt that withstands freezing temperatures to -6 degrees and can be spread with temperatures as low as 10 degrees
• The salt brine, used as a pre-treatment on city streets, is typically applied in dry weather two to three days before bad weather hits.
• When snow later hits the asphalt, the brine activates and lowers the freezing point of water. The object is to prevent the road surface and snow from bonding, not to melt the snow; this allows smooth, easy plowing.
• Traditional salt methods use 308 tons of salt to treat level 1 and 2 streets in Knoxville. At $71.14/ton it costs about $21,911 per application with 21 trucks and 42 employees.
• The new brine methods use 23 gallons of salt in 28,000 gallons of brine, costing $1,636 in salt per application, a savings of roughly $20,000—and requiring just four trucks and eight employees.
• The approximate $60,000 for the new system should be recaptured by winter's end.