Laura Fay IECA Environmental Connection February 18 2015 This work is based on NCHRP Synthesis 449 Strategies to Mitigate the Impacts of Chloride Roadway Deicers on the Natural Environment Revised Chapter 8 Winter Operations Salt Sand and Chemical Management and Toxicological Effects of Ch ID: 409744
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Slide1
Strategies to Mitigate the Impacts of Chloride Based Deicers to the Environment
Laura FayIECA Environmental ConnectionFebruary 18, 2015Slide2
This work is based on NCHRP Synthesis 449 Strategies to Mitigate the Impacts of Chloride Roadway Deicers on the Natural Environment, Revised Chapter 8, Winter Operations, Salt, Sand and Chemical Management, and Toxicological Effects of Chloride-Based Deicers in the Natural Environment. Slide3
Support for these research projects came from AASHTO Standing Committee on Highways, Transportation Research Board (TRB), National Highway Cooperative Research Program (NCHRP), and the National
Academies.Slide4
Acknowledgements…Dr. Xianming Shi
Jiang HuangMichelle AkinDavid VenezianoEric StreckerMarie VennerSlide5
Outline
Winter Maintenance PracticesEnvironments at RiskMitigation TechniquesConclusionsSlide6
Overview of WM OperationsSlide7
WM practices - Plowing
The physical removal of snow from the road using a snowplow.Slide8
Sanding
The application of sand, cinders, ash, etc. to improve friction on the road way.Slide9
Anti-icing
The snow and ice control practice of preventing the
formation
or
development
of bonded snow and ice by
timely
applications of a chemical
freezing-point depressant.Slide10
Deicing
The snow and ice controlpractice of breaking the
bond between
snow and
ice and the pavement
surface through applications
of a chemical
freezing-point depressant.Slide11
Pre-wetting
Application of liquid to solid material prior to placement on the road surface.ExamplesSalt brine sandSalt brine rock saltSlide12
Winter Maintenance Products
SandTreated sand (sand + 10% salt (s,l))Chlorides – NaCl, MgCl
2
, CaCl
2
(
s,l
)
Ag-based – beet, corn (l)Acetates & formates (s,l), glycols (l) & glycerin (l)Slide13
Product Application Rates
Sand – 100 to 1000 lbs/l-m (32°F and colder)Salt/sand – 400 to 1000 lbs/l-m (32 to 0°F)NaCl (32 to 15°F)
solid – 100 to 800
lbs
/l-m
liquid – 10 to 40 gal/l-m
pre-wet – 8 to 20 gal/l-m
MgCl
2 (32 to -5°F) and CaCl2
(32 to
-15°F)
solid – 100 to
500
lbs
/l-m
liquid – 10 to 40 gal/l-m
pre-wet – 8 to 20 gal/l-mSlide14
Benefits of W.M. Operations
Fewer accidents, improved mobility, reduced travel costs, reduced fuel use
Sustained economic productivity, continued emergency services, …Slide15
W.M. in the U.S.
> 70% roads, 70% population affected
Hwys
: 2.3 $
bln
/
yr
+
5 $
bln
/
yr
MnDOT
Case Study:
(4,600 crashes)= 29%
↓
$10.9M in travel time savings
$48.4M in user fuel savings
Total $227M saved,
b/c
of 6.2
Intangible benefits
Ye, Z., Veneziano, D.,
Shi, X.
Transportation Research Record
,
2013, 2329: 17.
Fay, L., Veneziano, D., Ye, Z., Williams, D.,
Shi. X.
Transportation Research Record
2010, 2169: 174.
Slide16
Shi, X.
Journal of Public Works & Infrastructure
2010, 2(4): 318.Slide17
Impacts of Salt and Chloride Based Deicers
www.witnerservices.net
www.ci.bellevue.wa.us
Photo courtesy of M. Mills
www.clf.org
www.modot.org
www.syracuse.com
www.miissoulanews.bigskypress.co
mSlide18
Impacts of Acetate Based Deicers
BOD
www.ci.bellevue.wa.us
Reduces available oxygen
for organism is the soil and
a
quatic environments.Slide19
Impacts of Sand and Abrasives
www.mto.gov.on.ca
www.itd.idaho.gov
www.utah.sierraclub.org
www.thunderbay.ca
www.kcsq.com
$ $ $Slide20
Strategic Planning for Reduced Salt Usage
Proactive versus Reactive MeasuresSlide21
Performance MeasuresWinter Operations Performance Measures
Mobility, reliability, accessibility, safetyExample: time to bare laneMeasured as: return to speed, friction, visual inspection, etc.
www.pbase.comSlide22
Performance Measures
Environmental Performance MeasuresMaintain or improve ecosystem, habitat, biodiversity, water quality, wetlands, air quality.Example: water quality monitoringData collection: hydrologic, biologic, atmospheric, etc.Resources
Environmental Guidebook (FHWA), Environmental Review Toolkit (FHWA), Center for Environmental Excellence (AASHTO), Eco-Logical, FHWA INVEST Sustainable Highways Self Evaluation ToolSlide23
Salt Management Plans
A statement of policies and objectivesIdentifies:Road use, salt vulnerable areas, storage sites, snow disposal sites, training, etc.DocumentationProposed approaches
Training and Management ReviewSlide24
Iowa DOT Salt Model
Allocates salt to garages based on weather conditions and policy usage requirements.Creates a salt budget for each garage
Annette Dunn, Iowa DOT Slide25
Training for Salt Management and Winter Maintenance Operations
Assess the needs of your staffConsider who is being trained and how to best convey that informationDesign training based on learning goalsTraining methods:Classroom, field, post-storm debriefing, simulator, etc.Slide26
Training Continued…
Have experienced staff conduct the trainingEvaluate your training programAssess how much information was learnedCommon training methods:Annual operator training, Snow University, Snow & Ice Rodeo, Computer Based Training (CBT)
www.capitalbay.com
www.triblocal.comSlide27
Monitoring and Keeping Records
Determine your baselineUse collected data to find trendsConsider tracking:Total length of roadWinter severity ratingNumber of events
Material used
Calibration dates
Treatment effectivenessSlide28
Calibration
Is a mustWhy: to realize savings gained from investment in new technology Train how to calibrate & keep recordsWhen to calibrate:When first acquired, points throughout a season, whenever a new material is used, after repairs, if there appears to be discrepancy in material usageSlide29
Material StorageAll products should be stored in a manner to minimize any loss of product.
www.syracuse.comSlide30
Management of Snow Disposal Sites
If moving snow to a melting location:
Minimize impacts (dust, litter, etc.)
Manage
meltwater
to comply with local water quality regulations
Routinely monitoring of site capacity, soil and water
The most effective way to dispose of snow is to let it melt where it accumulates.Slide31
Anti-icing
LOS, product, abrasives & plowing10 – 40 gal/l-mCost savings, mobility & safetySide benefit of reducing impacts to the environment, infrastructure, and vehicles.
Limitations:
Cold temps, rain/sleet, blowing snow, air temp above freezing and rising, high humidity
“the snow and ice control practice of prevent the formation or development of bonded snow and ice by timely applications of a chemical freezing-point depressant”Slide32
Pre-Wetting Solid Material
Adding liquid to products or abrasives at stockpile or at the spreaderBenefits
Eases product management and distribution
Accelerates breakup of snow/ice and enhances melting
Minimizes bounce and scatter, improves performance
Increases longevity on road = less frequent applicationsSlide33
Reducing Sand Usage and Managing Traction Materials
Pre-wetting Liquid productHot waterHeating sandUsing other materialsReduce
bounce/scatter
Apply in appropriate locations
Low speed roads, hills, curves, intersectionsSlide34
Sand and Abrasives Continued..The detrimental environmental impacts of abrasives generally outweigh those of chemical products.
Abrasives require more material and provide a lower LOS
www.syracuse.com
www.witnerservices.net
www.mto.gov.on.caSlide35
Precision Application to Manage and Reduce Chemical Applications
BenefitsImproved material placementReturn on investmentReduced chemical usageImproved environmental stewardship
Costs
Equipment
Maintenance
CalibrationSlide36
RWIS
Used to time treatments and determine which treatments to useBenefits: LOSCost savingsAid in maintenance response
Efficiency
Cost-benefit ratio
:
1.4
to 11
Real-time road condition informationSlide37
Pavement Sensors & Thermal Mapping
Monitoring, planning, treatment strategies, forecastingInvasive and non-invasive
www.vaisala.com
Maine DOT
www.enterpriseflasher.com
www.cbc.ca
www.bangordailynew.comSlide38
Friction Measurements
www.dot.state.oh.us
www.mastrad.com
www.highfrictionroads.com
www.vaisala.com
Indicator of road condition
Monitoring, planning, treatment strategy, prevent over application
Friction to assess Performance Measures (CDOT)
Non-contract friction measurements
Noticed difference in products performance
Provide good short/long term assessment of product performanceSlide39
Residual Chemical Measurement
Monitor road surface product concentrationOn-vehicle, embedded, or non-contactAccurate/recalibrated application ratesLink measurements with automatic spreader controlsBenefits:
Prevents over application, saves material and
$$$
Salinity sensors have been used to make educated decisions about reapplication (Ye et al., 2012).Slide40
Road Weather Management Decision Support
Software application, weather forecast and predictions, road weather reports, training tools.
Benefits:
Cost
and material
savings, benefit-cost: 1.33 to 8.67, less use of vehicles
Lessons learned:
Time needed to refine forecast & get management on board, continued training and exposure
Tools that integrate road weather forecasts, coded maintenance rules of practice, resource data to provide recommended treatment strategies (FHWA 2011)Slide41
MDSSSlide42
Weather Forecasts and Information Services
Research has shown that winter maintenance costs decrease as the use of weather information increases (Ye et al., 2009).Accurate and timely forecasts have been shown to save 11–25% (labor) and 4-10% (material), but using a
bad forecast can cost you
(Shi et al., 2007)
Improved spatial resolution will provide greater expected benefits to service levels (Fu et al., 2009).Slide43
Drift Control and Snow Fences
≥
8
ft
Wildlife habitat, control erosion, improve water quality, reduce spring-time flooding, sequester carbon.
Reduce blowing and drifting snow
Low cost snow storage
Increased safety
Reduce need for snow & ice control product
25 year lifespan at
$1.40 per
ft
2Slide44
Fixed Automated Spray Technology (
FAST)Slide45
FAST Summary…
BenefitsReduced mobile operationsReduced crash frequency & delayLess material requiredChallenges
Activation frequency
System maintenance & training
Installation should be site specificSlide46
Proactive BMPsEPA pollution prevention for operation and maintenance of highways:
Cover salt storage piles and deicing materialsStore all materials outside of the 100 yr flood plainRegulate application ratesUse specialized application equipment
Avoid dumping snow into surface watersSlide47
Reactive Strategies
So there are deicing chemicals and sand out on the road and in the environment, what do we do now - Clean it up - Capture it
- Dispose of itSlide48
Storage and Release
Detention, Retention, &Evaporation PondsWetlands and Marshes
The primary mechanism of storage and release BMPs is mixing of runoff to reduce peak chloride concentrations .Slide49
Infiltration
Infiltration trenches and basins treat runoff and reduce surface runoff water by allowing water to infiltrate into the surrounding/underlying soils and groundwater systems.
Avoid if location has a
shallow water table
.
Chlorides can be stored
and later released in
greater concentration
.Slide50
Alternatives methods to remove chlorides?
Capturing chlorides in filter media (dolomite, calcium, or recycled concrete)> Sorption of chloride to filter media.More research is needed to determine the effectiveness.(Villagran-Zaccardi et al., 2008)Slide51
Conclusions
Deliver the right type & amount of materials in the right location at the right time
effectiveness & efficiency of winter operations
material usage, $$$, environmental footprint
Balancing
LOS
vs.
sustainability
: best practice
in technology & management domainsSlide52
Questions?
www.cylelicio.usSlide53
Thank you for your time.
Laura FayWinter Maintenance & Effects Program ManagerResearch Scientist IIWestern Transportation Institute
Montana State University
l
aura.fay@coe.montana.edu
406-600-5777Slide54
Report Authors
Laura Fay
Michelle Akin
Xianming Shi
David Veneziano
.
http://maintenance.transportation.org/Documents/nchrp%2020-7_Task%2013Revised%20Chapter%208%20with%20Summary%20of%20Research.pdf
Photo courtesy of GNPSlide55
We would like to thank the following people for their efforts on this project:
Caleb DobbinsWilliam HoffmanSteve LundDebra NelsonWilfrid NixonMax Perchanok
Gabriel Guevara
Leland Smithson
Frank Lisle
Amir Hanna
Annette Dunn
Monty Mills
Michael Williams
Brian BurnSlide56
Salt Matrix and Pre-set Spreader Application Rates
Goal: Reduce application rates while maintaining same or better LOS.Considers: pavement temp., heating/cooling trends, road condition at time of service, available maintenance strategies.Provides
: recommended application rates for liquid and solid for initial and subsequent treatments on reference sheets
4 storm scenarios (light, moderate, & heavy snow, and freezing rain.
Drivers use their judgment to make decisions.
Kentucky Department of HighwaysSlide57
Stewardship Practices for Reducing Salt, Sand and Chemical UsageSlide58
Anti-icing
Direct Liquid Application (DLA)Benefits: reduced application ratesreduced loss of material
Faster storm cleanup
Quick acting
Further bond prevention
Expanded toolbox
“the snow and ice control practice of prevent the formation or development of bonded snow and ice by timely applications of a chemical freezing-point depressant”Slide59
Benefits (per winter season)
Assume 30% MDSS recommendations were followed.
Costs per winter season: $332,879
Benefit-Cost Ratios:
2.1 (Same Conditions); 2.6 (Same Salt)
59
NH: MDSS Benefits & Costs
Scenarios
Delay
Savings
Crash
Savings
Resource
Savings
Total
Savings
Same Conditions
$5,039
$335,052
$354,661
$694,752
Same Salt
$72,461
$786,385
$6,624
$865,470
Ye, Z., Strong, C.K.,
Shi, X.
, Conger, S., Huft, D.
Transportation Research Record
2009, 2107, 95-103. Slide60
Spread PatternsWindrowed on the crown
Center line applicationSpread uniformlyBroadcastSlide61
Reports on to look for….
Comparison of Material Distribution Systems for Winter Maintenance Phase IDevelopment of a Totally Automated Spreading SystemSlide62
Material Distribution Systems
Tailgate Spreaders & Reverse dumpingMultipurpose spreadersRear Discharge SpreadersZero velocity spreadersDual spinnersSpinner
Modified spinners
Homemade chutes
Challenges
Mechanical failure
Clogging & freezing
Corrosion
Frequently calibrationSlide63
Tailgate Spreaders and Reverse Dumping of Dual Dump Spreaders
BenefitMultipurpose spreader that can be used year roundChallengeHeavy
Need to raise body, reduced stabilitySlide64
Rear-Discharge Spreaders
Designed to pre-wet, fine grained saltPre-wet at: spinner, hopper using auger, or both.Allow for “high-ratio” or “slurry” salt application30:70 liquid-to-solid by weightRequires large capacity liquid tanks and adequate pumpingSlide65
Case Study: Slurry Technology
High volume liquid anti-icer to dry salt (30%:70%) ~ 60-90 gal/ton200 lb/l-m = ~ 9 galOatmeal consistency, salt grains fully saturated
Slurry auger and at spinner
(Maine DOT 2005)Slide66
Slurry Technology Contd.
Lesson Learned¾ in salt allowed but smaller grains work better.Start with a heavier application, followed by smallerSome equipment has worked better than others
Pumps, on
board
crushers, overall
equipment
design/functionality
Material and cost savings (Maine DOT 2005)
Anecdotal comments: Goes into action quicker, acts immediately, lasts longer on road, out-perform traditional pre-wetting methods, minimizes bounce and scatter.Slide67
Electronic Spreader Controls
Pre-set or on-demand application ratesUse electronic ground speed controls to provide consistent application rates.Can be linked with sensors (e.g. friction, AVL, GPS)Modern units can record information aboutApplication rate, gate position, run time, blast information, avg. spread width/symmetry.Slide68
Rearward Casting Spreaders(Ground-Speed and Zero-Velocity Spreaders)
Material is discharged rearward at the same speed as the spreading vehicle is traveling forward.Keeps more material on the road where it was placed.Application speeds should not exceed 35 mph, higher speeds reduce application accuracy.Slide69
Proactive BMPsMaryland Department of the Environment BMPs for WM:
Use right material for temperatures/conditionsSweep/vacuum excess material from roadApply material only when necessaryMix sand with granular materialConsider alternative materials with lower application ratesSlide70
Reactive BMPsAssess contamination site
Location of nearest maintenance facilityIdentify potential sources of contaminationInterview local staffRecommend actions to address issue
Review historical data
Inspect site and neighboring areas to determine other potential sources