Presentation on theme: "Environmental Issues Associated With Asphalt Shingle Recycling Presented at the 3 rd Asphalt Shingle Recycling Forum Chicago, Illinois November 1-2, 2007."— Presentation transcript:
Environmental Issues Associated With Asphalt Shingle Recycling Presented at the 3 rd Asphalt Shingle Recycling Forum Chicago, Illinois November 1-2, 2007
Jon T. Powell, E.I. Innovative Waste Consulting Services Gainesville, Florida
Project Background Initial involvement to help develop Compiled a white paper on behalf of CMRA and EPA that: – Summarized two environmental questions/concerns raised regarding shingle recycling – Collected data from recyclers in the US – Evaluated analytical data Published Recycler-supplied – Incorporated input from CMRA, EPA, UNH Will keep updating available analytical data as it is collected
Presentation Outline Background Overview of Asphalt Shingle Recycling Environmental Questions or Issues – Asbestos – Polycyclic Aromatic Hydrocarbons (PAHs) Conclusions On-going research in Florida
Background Asphalt shingles are the most common roofing material in North America Great market potential for recycling Approximately 11 million tons of asphalt shingle waste is generated per year – Post manufacture (scrap): 1 million tons – Post consumer (tear-off): 7-9 million tons
Typical Composition of An Asphalt Shingle Base (fiberglass or organic felt) Waterproofing asphalt Granular/aggregate Back surfacing ComponentOrganic FeltFiberglass Mat Asphalt cement30-36%19-22% Felt2-15% Mineral granules/aggregate 20-38% Mineral filler/stabilizer8-40%
Raw Material Asphalt shingles is dropped off by roofing contractors.
Horizontal mill for size reduction
Overhead magnet used for the “under” and “over” streams
Unders – Used as HMA additive Overs – used as covering and paving material for unpaved roads
Asphalt Shingles Excavator Shredder Trommel Screen Overhead Magnet Fine ASR Coarse ASR Basic Layout of Post-Consumer Asphalt Shingle Processing Facility Basic Layout of Post-Consumer Asphalt Shingle Processing Facility Ferrous Metal Overhead Magnet Ferrous Metal
Environmental Concerns ASBESTOS PAHs
Possible Exposure Pathways GrindingHMA Pavement, mulch, etc. Release of Asbestos? PAH emissions? PAH leaching? or
Health Impacts Asbestos – Lung cancer – Mesothelioma PAHs – Cataracts, kidney and liver damage – Some PAHs are identified as carcinogenic
Pathways of Possible Exposure at Recycling Operations Generator Processing Facility (storage, grinding) Most likely pathways of exposure
Pathways of Possible Exposure for Recycling Operations Generator Processing Facility (storage, grinding) Asbestos Air Emissions Water Emissions PAH Use in HMA Direct Use Human Contact PAH Regulatory pathways of concern Water Emissions PAH Air Emissions PAH
Types of Asbestos Chrysotile Amosite Crocidolite Tremolite Actinolite Anthophyllite
Was Asbestos Widely Used? Manufacturer Years Manufactured Product Barber Asphalt CorporationNAAsphalt-asbestos roof felt Carey Manufacturing Company NA Asphalt-asbestos shingles, asbestos finish felt, mastic The Celotex Corporation1906 through 1984Asphalt roof coating and other miscellaneous materials Fibreboard Corporation1920 to 1968 Roof paint, roll roofings with asbestos-containing base sheets, caulking compounds, plastic cements, taping and finishing compounds General Aniline and Film Corporation NARoofing asphalt Johns-Manville Corporation1891 through 1983 Asphalt-asbestos shingles, rag-felt shingles, fibrous roof coating, shingle tab cement, roof putty Kaylite CompanyNA Asbestos surface coating for shingles National Gypsum Company1941 through 1981 Roofing and shingles Monroe CompanyNA Asbestos surface coatings for shingles Rhone-Poulenc Ag Company Early 1930s through 1976 Adhesives, coatings, sealants, and mastics United States Gypsum Company 1930 through 1977Paper and felt
Asbestos roof shingles (transite) were fairly common; however, this is not the same thing as asphalt shingles. There were also a lot of other roofing products that used asbestos.
ROCK_W0QQitemZ QQihZ002QQcategoryZ37831QQssPageNameZ WDVWQQrdZ1QQcmdZViewItem “This roofing is made by crushing solid asbestos rock and compressing the long fibres into a dense, homogeneous felt. Several layers of this rock are then permanently cemented together with nature’s greatest water- proofer, Trinidad Lake Asphalt, making a light-weight roofing that is virtually a solid sheet of pliable stone.”
Asphalt Shingle Testing Results for Asbestos Data from processors in Maine, Iowa, Florida, Missouri, Minnesota, and Massachusetts Data available for 27,694 samples collected – 18 detections asbestos content <1% – 408 detections asbestos content >1% – Overall, asbestos detections in 426 samples Approximately 1.53%
Asbestos Summary Asbestos was used in the manufacture of asphalt shingles and asphalt-containing roofing materials in the late 1800s, continuing through to the 1980s. Asbestos phased out as component of asphalt shingles in the early 1980s. Data on asbestos content in asphalt shingles is very limited. Service life of an asphalt shingle is around two decades, +/-.
Asbestos Summary It is common practice in re-roofing to install new shingles directly on top of old ones. – As such, a load of post-consumer asphalt shingle waste may contain multiple layers of asphalt shingles of varying age.
Asbestos Summary Analytical results of over 27,000 asphalt shingle samples indicated that about 1.5% of all samples detected asbestos. – Many asbestos detections were caused by other materials such as mastic that were attached to the samples.
Asbestos Summary Despite the interference in the samples from the presence of mastic, the limited number of asbestos detections was consistent with the fact that asbestos was mostly phased out in the 1970s and that the typical reported service life for asphalt shingles is around years, although effect of new shingles being installed on old ones may impact detection.
Asbestos Summary Obtaining/sourcing uncontaminated material should further reduce incidence of asbestos in samples – Some states restrict where the shingles can come from
A group of over 100 different chemicals Formed primarily during the incomplete burning of coal, oil and gas EPA identifies 7 PAHs as probable human carcinogens – Benz(a)anthracene, Benzo(a)pyrene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Chrysene, Dibenzo(a,h)anthracene, Indeno(1,2,3- cd)pyrene What are Polycyclic Aromatic Hydrocarbons (PAHs)?
PAH Issues Raised Some have raised question of whether PAHs should be a concern when recycled asphalt shingles are: Ground up and used as road base Ground up and used as mulch – Leaching? – Direct Exposure? Used in HMA – Air emissions?
PAH Summary Asphalt shingles naturally contain PAHs. A leaching study on discarded asphalt shingles indicated that PAHs did not readily leach PAHs. Related studies on virgin roofing asphalt, reclaimed asphalt pavement, and run-off from asphalt pavement indicated PAH concentrations below the laboratory detection limits. – However, since that study some acceptable levels have decreased – Additional data are required to detect these samples at lower concentrations
PAH Summary PAHs are emitted during HMA production – Pollution control equipment reduces PAH concentrations The effect of using post-consumer asphalt shingles in HMA on PAHs is unknown The use of post-manufacture asphalt shingles is permitted in some states A study in Texas investigating the issue of PAH emissions in HMA production has not yielded any data to date
PAH Summary It is not anticipated that clean, uncontaminated asphalt shingles would cause PAH emissions to be significantly different than virgin asphalt
Recommendations to State Regulators You can obtain a copy of our White paper, which provides recommendations for information and demonstrations a facility should make to recycle post-consumer asphalt shingles as part of permitting
RISK ASSESSMENT OF THE REUSE AND DISPOSAL OF SEVERAL ASPHALT WASTE MATERIALS Ongoing Research
Overview University of Florida Department of Environmental Engineering Sciences – Solid and Hazardous Waste Laboratory Objectives: – Measurement of PAHs using instrumentation with lower detection limits (shingles and RAP) – Risk-based analyses of PAHs and other chemicals