Environmental Impact and Life-Cycle Analysis of Winter Roadway Abrasives
Under 1 year
BACKGROUND: Recent research has challenged the effectiveness of roadway abrasives in certain settings, but states throughout the nation still use roadway abrasives as part of their winter maintenance programs. The use of these winter abrasives, such as sand or other products, can be costly to DOTs. At a typical application rate of 1200 lbs per lane mile, product cost, post event sweeping, waste management, and waste disposal can be significant cost considerations. Abrasives can create a post-storm waste stream that requires regular street sweeping to control the materials from entering drainage systems. Often, spent abrasives are contaminated through exposure to compounds found on road surfaces; therefore, the collected street sweepings must be sent to regulated landfills. In addition to routine maintenance and disposal costs, there are environmental costs associated with the use of roadway abrasives. Abrasives are contributing directly and indirectly to airborne particulate matter (PM-2.5). Indirect particulate matter has been shown to come from the actual road surfaces wearing as a result of the "sandpaper" effect. An Oregon DOT study found that even after sweeping, 50-90% of applied sand remains in the environment. When these abrasives are transported through drainage systems, they can increase stormwater Best Management Practice (BMP) maintenance costs and potentially reduce BMP performance. An informal AASHTO query of state DOTs, indicated that some states do not use, or have eliminated the use, of abrasives in their winter maintenance programs. Given the questionable effectiveness of winter abrasives and the costs for cleanup and disposal, alternative deicers may be more cost effective. A life-cycle comparison of abrasives versus deicers could also consider the potential for Total Maximum Daily Load (TMDL) sediment credits to be generated through reductions in the application of such materials and be used towards meeting sediment waste-load reductions. Additionally, reusing spent abrasive material in other roles such as alternative fill material may be more cost effective than landfill disposal.
OBJECTIVE(S): The primary objective of this research is to develop a report that includes an overview of the state of the practice regarding winter abrasives, an evaluation of the life-cycle costs and environmental impacts of abrasives versus alternative deicers as well as abrasive disposal versus abrasive reuse, and recommendations regarding application of abrasives versus their alternatives. Tasks required to meet the research objectives include: • Summarize quantity and characteristics of nationwide abrasive use; • Synthesize previous research on the effectiveness of winter abrasives for traction control; • Evaluate the life-cycle costs of abrasives versus alternative deicers, including: o procurement; o application; o sweeping; o disposal; o reuse; o impact to road surfaces; and o impact to water and air quality; • Evaluate potential for spent abrasives to be used as alternative fill or other uses • Evaluate the feasibility of potential TMDL credits for eliminating abrasives; and • Provide best practice recommendations to DOTs nationwide
Some states have recognized the limited effectiveness and environmental impacts of winter abrasives and have subsequently reduced the use and cost of abrasives as a winter roadway maintenance practice. However, many states throughout the nation continue to employ winter abrasives and do not have a sufficient decision tool with which to make practice choices. At procurement costs of $5-30 per ton, reducing, eliminating, or reusing winter abrasives is a potentially sustainable and economically profitable action for DOTs. Potential benefits enabled through the proposed research include: • Provide the basis for reducing or eliminating a winter maintenance practice that does not exhibit favorable life-cycle-benefits; • Provide the basis for alternative uses of spent abrasive material; • Reduce environmental impacts to surrounding water and air; • Provide support to pursue TMDL sediment credits from the state TMDL authority or EPA.
ADC60 TRB Committee on Resource Conservation and Recovery
May 26, 2016
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