CDOT's Southwest Maintenance team wins 2012 environmental award
Maintenance Section 3, headquarted in Durango and covering 6 ½ counties* in southwest Colorado, received one of just three awards given.
Each year, CDOT reviews environmental award submittals in four categories: Maintenance, Projects, Innovative Processes and Special Contributions. Section 3 crews won in the Maintenance category for their in-house production of a salt brine as a liquid deicer.
“Traditionally, CDOT uses magnesium chloride as the base product for snow and ice operations,” CDOT Section 3 Maintenance Superintendent Kyle Lester said. “We began experimenting with the use of salt brine as a liquid deicer in 2006 in an effort to reduce the concentration of chlorides that are introduced into the environment.”
In 2009, maintenance section staff developed their own brine-making system that produces 24,000 gallons in just four hours. This salt brine production process continued to evolve, with the integration of a wastewater recycling system. In 2010, staff developed an automated salt brine production system that recycles waste water from the maintenance patrol barn floor drains and wash bay. The recycled water is filtered for heavy metals and other contaminates, then mixed into the salt brine. (Section 3 has three Maintenance Areas, located in Durango, Cortez and Ridgway, and all three areas are producing the salt brine. Waste water recycling is in operation at only the Cortez and Ridgway maintenance areas currently; the Durango area will eventually begin this process, as well.)
Eventually, the system at all maintenance areas will be fully computerized and fully automated. Operators will load a circular hopper (conveyer) with salt, and sensors on the mixing tank will monitor the solid salt level and the salinity of the brine.
Lester summarizes the environmental and economic benefits of the use of salt brine as a liquid deicer:
- Reduces the number of chlorides introduced into the environment half, as compared to magnesium chloride, due to the lower amount of chloride ions in the material.
- Cortez and Ridgway production facilities recycle of their waste water by filtering out the heavy metals; after the metals are filtered the clean water is then pumped to storage tanks were it is made into Salt Brine
- Salt brine is less expensive than magnesium chloride products; Section 3 used 612,152 gallons for pre-wetting sand and as a liquid deicer last winter, saving $394,030. (For comparison, the salt brine (including production and transportation costs) averages about .41 cents per gallon—other liquid deicing products have a per-gallon cost ranging from .70 cents to $1.25.)
- Salt brine is quicker to produce on-site, than have liquid deicers delivered; crews can produce 24,000 gallons in an eight-hour shift.
*CDOT Maintenance Section 3 covers maintenance activities the counties of: Montezuma, La Plata, Dolores, San Juan, San Miguel, Ouray and the southern half of Montrose. The Section includes the following maintenance areas and patrols:
Durango Maintenance (King) Area
The Durango Maintenance Area has six patrols, located in: Pagosa Springs, Bayfield, Ignacio, Durango, Hesperus and Rockwood. The Durango Maintenance Area has 43 maintenance workers and 35 pieces of snow removal and avalanche equipment (including 22 snowplows, 12 of which are equipped with MDSS). Eleven trucks are equipped with liquid deicer applicator tanks. Other plow trucks carry sand/salt and for providing traction. Durango maintenance crews take care of 510.36 lane-miles. During last winter, Durango maintenance crews plowed 167,650 total lane-miles. As well, crews sprayed 543,070 gallons of liquid deicing products (all deicers, including salt brine), spread 6,115 tons of sand/salt and spent 98 hours on avalanche control missions.
Cortez Maintenance (John) Area
The Cortez Maintenance Area has six patrols, located in: Dove Creek, Cortez, Mancos, Dolores, Rico and Telluride. The Cortez Area has 31 maintenance workers and 37 pieces of snow removal and avalanche equipment (including 23 snowplows, 6 of which are equipped with MDSS). Cortez maintenance crews take care of 650.8 lane-miles. During last winter, Cortez maintenance crews plowed 131,678 total lane-miles. As well, crews sprayed 255,130 gallons of liquid deicing products (all deicers, including salt brine); spread 5,829 tons of sand/salt, and spent 230 hours on avalanche control missions.
Ridgway Maintenance (Mary) Area
The Ridgway Maintenance Area has seven patrols, located in: Cascade, Silverton, Ouray, Ridgway, Norwood, Nucla and Paradox. The Area has 33 maintenance workers and 35 pieces of snow and avalanche removal equipment (including 19 snowplows, 2 of which are equipped with MDSS). One truck is equipped with a liquid deicer applicator tank. Other plow trucks carry sand/salt for providing traction. Ridgway maintenance crews take care of 588.84 lane-miles. During last winter, Ridgway maintenance crews plowed 158,109 total lane-miles. Crews sprayed 139,696 gallons of liquid deicing products (all deicers, including salt brine), spread 11,605 tons of sand/salt and spent 1,745 hours on avalanche control missions.
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