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Innovative solutions to provide environmentally acceptable deicing

Description:

Each winter maintenance season, concerns arise regarding the use of NaCl (both granular and brine) for anti-icing purposes. Along with these concerns are requests for the agency to use some alternative chemical and/or prove that the use of NaCl at their current application rates is not resulting in environmental harm. Yet, at the same time, the use of NaCl by some agencies has increased drastically in the recent past, in response to the escalation of public expectations related to roadway level of service during and immediately following a winter maintenance event.

Additionally, over the past several years there's been a dramatic uptick in the building of new or replacement infrastructure. With costs in the billions of dollars and expectations of 100 plus year service lives, corrosion from deicers is a big concern. Review of research into alternative deicing materials shows studies from the 1990's that are still the state of the art. Alternative materials are available, but they are generally perceived as prohibitively expensive (from a first cost basis anyhow) and many have their own associated environmental impacts. There also is a need to coordinate and standardize the effects of investigating and mitigating the impacts of deicers on surface and ground waters so that this environmental risk can be better understood and managed, across the diverse road weather regions/scenarios and diverse water/soil contexts.

Increasing the use of salt brine and other liquids have been purported to help reduce overall deicer use, but manufacturing liquids could put a strain on local potable water supplies and could prevent some departments of transportation (DOTs) from expanding the use of liquids and brine.

Objective:

There are a few pressing needs in the area of environmentally acceptable deicing methods:

  • Development of NaCl application limit thresholds (e.g., total wintertime pounds per lane mile) below which no environmental harm – primarily to surface and groundwater sources – is expected. This threshold could be based on annual precipitation amounts and local environmental conditions. It would serve as a measuring tool for the general public and possibly as a goal for the DOTs.
  • Guidelines for investigating and mitigating the impacts of highway deicers to the surrounding water bodies and highway infrastructure.
  • Research and evaluations on pre-wetting materials and other strategies to reduce overall salt usage.
  • Development of commercially viable alternative deicing materials.
  • Using reclaimed water as an alternative source in the production of salt brine.
  • Precise measurement of residual deicers. Knowing precisely how much salt is left on the road might lead to less actions of salting, and therefore, reduced negative environmental impacts.
  • Balancing environmental and corrosion concerns with increasing performance and safety expectations.
Benefits:
  • Reduce deicing costs by DOTs.
  • Reduce impacts to the environment.
Implementation:

DOTs will use the information gained from this research to determine the best deicing procedures, materials, and equipment so that they can improve snow fighting efforts. This will allow DOTs to keep the roads open which improves mobility for the public.

Sponsoring Committee:AHD65, Winter Maintenance
Research Period:12 - 24 months
Research Priority:High
RNS Developer:Joe Horton, Tina Greenfield
Date Posted:07/26/2017
Date Modified:08/02/2017
Index Terms:Deicing, Sustainable development, Environmental impacts, Winter maintenance, Deicing chemicals, Brines, Sodium chloride, Alternatives analysis,
Cosponsoring Committees: 
Subjects    
Highways
Maintenance and Preservation
Environment

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