Freeze separation for recycling road salt contaminated melt water

Freeze separation was examined as a method to concentrate dilute salt in snow melt and sand recycling wash water into concentrated brine at a City of Edmonton snow storage and sand recycling facility. Brine with salt concentrations as low as 15 g/L, with road sand and crystal salt, was found to be reusable as a de-icer. Field data confirmed the occurrence of natural freeze separation onsite. The first portions of the melt often had salt concentrations more than 10 times the average concentration in the bulk snow. The natural separation of salts can be further enhanced physically by collecting the first portion (high concentration) of the snow melt and subsequently spraying it into the cold winter air (spray freezing). A spray freezing field investigation showed that up to 90% of the chloride and sodium was released from the spray ice cores within the first 19% of the melt water.