Held at the University of Miami, College of Engineering
Coral Gables, Florida
Kevin Archer, Chemical Specialties Inc., Charlotte, NC
Sean Bennie, University of Miami, Coral Gables, FL
Mark Bingham, Dade Recycling, Miami, FL
Scott Conklin, Universal Forest Products, Grand Rapids, MI
Diana Davis, Florida Power and Light, Juno Beach, FL
David Dee, Landers & Parsons, Tallahassee, FL
Louis DiVita, Delta Recycling Corp., Pompano Beach, FL
Rick Donaldson, Great Southern Wood Preserving, Bushnell, FL
Keith Drescher, Florida Power and Light, West Palm Beach, FL
Tom Evans, Coastal Lumber, Weldon, NC
Kelvin Gary, University of Miami, Coral Gables, FL
Bill Gay, Langdale Forest Products, Valdosta, GA
Alex Gomez, Dade Recycling, Miami, FL
Jeff Gould, Florida Dept. of Environmental Protection, Ft. Myers, FL
Bob Gruber, Hickson Corp., Smyrna, GA
Jimmy Harris, Great Southern Wood Preserving, Bushnell, FL
Jim Healey, Koppers Industries Inc., Gainesville, FL
Jim Hickman, Langdale Forest Products, Valdosta, GA
Naila Hosein, University of Miami, Coral Gables, FL
Gary Hurst, Robbins Manufacturing, Tampa, FL
Mitch Joiner, Osmose Wood Preserving, Griffin, GA
Russel Ketchem, Florida Power and Light, West Palm Beach, FL
Bernine Khan, University of Miami, Coral Gables, FL
Frank Klasnick, Osmose Wood Preserving, Griffin, GA
Monika Kormienko, University of Miami, Coral Gables, FL
Danny Kreiser, East Coast Recycling, Ft. Pierce, FL
William Krumbholz, Ft. Myers, FL
Jim Langdale, Langdale Forest Products, Valdosta, GA
Marc Laurent, Miami-Dade County Solid Waste, Miami, FL
Dave Mason, FL Dept. of Environ. Protection, Tallahassee, FL
Jerry McMullan, Florida Power and Light, West Palm Beach, FL
Russ Morgan, Occidental Chemical, Castle Hayne, NC
Don Pardue, Wood Treaters, Jacksonville, FL
George Parris, American Wood Preservers Inst., Fairfax, VA
Scott Ramminger, American Wood Preservers Inst., Fairfax, VA
Jay Robbins, Robbins Manufacturing, Tampa, FL
Tom Roberts, Delta Recycling Corp., Pompano Beach, FL
Steven Roundtree, Southeastern Lumber Manufacturers Assoc., Forest Park, GA
John Schert, Univ. Florida Florida Center for Solid and Haz. Waste Mgt., Gainesville, FL
Jim Seufert, Universal Forest Products, Grand Rapids, MI
Helena Solo-Gabriele, University of Miami, Coral Gables, FL
Gus Staats, Osmose Wood Preserving Division, Griffin, GA
Kristin Stook, University of Florida, Gainesville, FL
Thabet Tolaymat, University of Florida, Gainesville, FL
Tim Townsend, University of Florida, Gainesville, FL
George Varn Jr., Varn Wood Products, Hoboken, GA
Shakir Wissa, Southern Soft Wood Inc., Orlando, FL
Edward Zillioux, Florida Power and Light, Juno Beach, FL
The meeting began at 1:05 pm.
Helena Solo-Gabriele welcomed all the attendees to the meeting. Each attendee introduced themselves by stating their name and affiliation. John Schert described the initiatives of the Florida Center for Solid and Hazardous Waste Management. Helena Solo-Gabriele reviewed the agenda and mentioned that Bill Hinkley will not be making a presentation due to illness.
2. History of Research Project and Review Revised Draft of Final Technical Report for Yr 2
Helena Solo-Gabriele described the history of the project. The project was initiated several years ago due to elevated metals concentrations observed in the ash from wood cogeneration plants. A mass balance analysis was developed as part of the year 1 study to determine whether CCA treated wood was a likely cause. From the mass balance it was found that the quantities of CCA treated wood disposed will increase significantly in the future. Samples collected from construction and demolition (C&D) facilities indicate that roughly 6% of wood waste recycled at these facilities is CCA treated. Energy recovery was found to be the primary disposal pathway for the recycled wood waste during 1996; however, today mulch is becoming more significant; reference was made to a newspaper article that quotes the owner of a retail outlet stating that the mulch sold at the outlet is made of treated wood. Given this situation, the focus of the year 2 study was to develop tools for better managing this waste stream. Technologies were evaluated for sorting CCA-treated wood from other wood types. These technologies included the use of chemical stains and x-ray fluorescence. Both technologies performed well in the laboratory. During year 2 the research team also evaluated leaching characteristics of CCA-treated wood ash. The leaching study included TCLP and SPLP tests as well as extractions using other chemicals. TCLP tests showed that CCA-treated wood ash will likely be classified as a hazardous waste, even when CCA-treated wood represents less than 5% of the mixture. Results from the solvent extraction study changed since the last TAG meeting due to new data collected concerning the total metals concentrations in the ash. Results showed that nitric acid was the most effective solvent, the mobile portion of the chromium was readily leached using weak solvents, and that citric acid was particularly effective at extracting significant quantities of arsenic. Recommendations were to further explore ash treatment technologies and opportunities for recycling the metals in the ash.
George Parris: Was the ash matrix analyzed? Both neutron activation and the scanning electron microscopy (with x-ray detection) are capable of analyzing for many different elements.
Response: The analysis focused on chromium, copper, and arsenic. It is recognized that the analytical procedure can analyze for more elements; however, due to limitations in funds the analysis was focused on three elements.
Ed Zillioux: What was the original retention level of the weathered wood sample?
Response: The weathered wood sample, a utility pole, was originally rated at 0.6 pcf. However, direct analysis of the retention level of this sample indicated that the actual retention level was higher.
John Schert: The ratio of chromium to copper tends to differ for the different ash samples. What is the variability of the neutron activation analysis.
Response: The variability of the analysis is within order of magnitude. The variability is likely due to sample heterogeneity.
Questions: How were the background arsenic concentrations determined?
Response: The background levels were determined through a separate study coordinated by Lena Ma of the University of Florida. The background levels are intended to represent natural background levels that are un-impacted by people. Lena Ma's work found a strong correlation between background metals concentrations and type of soil. She found that 75% of the soils analyzed were less than the Florida Department of Environmental Protection (FDEP) residential guidance concentration of 0.8 mg/kg.
Question: What is the background metals concentration in ash made from bagasse?
Response: It is likely on the same order of magnitude as the untreated wood control which was on the order of 100 mg/kg for each metal.
George Parris: For the scaling computations is it realistic to assume that the arsenic from CCA is spread over the top 1 inch of soil?
Response: The purpose of the computation is to scale the cumulative arsenic disposal quantities to a readily conceived potential impact. It is provided to show that the amount of arsenic disposed is significant.
Current Research Activities: Original Year 3 Study
The objectives for year 3 focus on evaluating alternative chemicals (phase I) and on developing disposal management strategies (phase II). Alternative chemicals are considered to represent a potential long-term solution to the disposal problem associated with CCA-treated wood. Disposal-end management strategies are needed to handle short-term (next 25 to 40 years) disposal of CCA-treated wood. Disposal-end management strategies are separated into three tasks: field demonstration of sorting technologies, evaluation of pyrolysis technology, and developing a sourcebook for the wood disposal sector. Chemicals considered for phase I include those that contain no arsenic, have been used commercially to some extent, have been standardized by the American Wood Preservers' Association (AWPA), and are waterborne preservatives. Seven chemicals have been found that meet these criteria: AAC, ACC, ACQ, Borates, CBA, CC, and CDDC. Methods for evaluating these alternatives include contacting manufacturers, reviewing AWPA standards, and sending questionnaires to large-end users and wood treaters concerning perceived advantages and disadvantages in the use of alternative chemicals. Contacts have been made with alternative-chemical manufacturers and the AWPA standards have been reviewed. Questionnaires have been mailed. An initial evaluation was provided for the four most promising alternatives which include ACQ, CBA, CC, and CDDC. Kelvin Gary provided a review concerning corrosion issues, depletion/leaching, and efficacy. Costs were summarized for a 12 foot deck board. It was mentioned that the alternatives listed contain copper which may not be acceptable for submerged water use. Future tasks include continued follow-up with the questionnaires and write-up of a report on alternative chemicals.
Keith Drescher: The recommended fasteners for CCA-treated wood are hot-dipped galvanized. Was information on the corrosion of such fasteners available?
Response: Most of the information available from the alternative chemical manufacturers indicated that fasteners were galvanized. Most did not specify whether the galvanized fasteners were hot-dipped or electroplated. The research team has contacted the alternative chemical manufacturers for this information.
George Parris: Creosote is a potentially viable alternative chemical for marine applications. Also, there has been a rumor that a facility is currently being retrofitted within Florida to treated with an alternative chemical.
Response: John Schert stated that there has been some grant money set aside to retrofit the Pride wood treatment plant to utilize a non-arsenical chemical for treatment purposes.
Scott Conklin: The entire life cycle should be evaluated when choosing alternative chemicals.
Response: True. The research team has proposed to conduct a life cycle analysis on the alternative chemicals within the year 4 pre-proposal.
Bob Gruber: What is the logic for recommending a switch to non-CCA-treated products for marine applications, given that the impact of CCA-treated wood in the marine environment is minimal?
Response: Ultimately CCA-treated wood from marine applications will be disposed. Upon disposal, this wood will contribute to high arsenic concentrations within the disposal stream.
Scott Ramminger: What would be the regulations that would apply if the ash from alternative chemicals were land applied?
Response: The primary metal regulated in the ash from the alternative chemicals would be copper. The copper regulations for land application of sewage sludge, which are used as guidelines to regulate land application of other wastes, allows for higher copper concentrations relative to that of arsenic.
Question: Has stabilization of the CCA-treated wood-ash within a cement matrix been evaluated?
Response: Stabilization of the ash within a cement matrix for ultimate disposal is a possibility; however, it will likely be expensive.
George Parris: Disposal of CCA-treated wood with municipal solid waste (MSW) should be investigated. The impacts of such a practice should be minimal. Also, there are other components in construction and demolition (C&D) and MSW, such as lead and cadmium. Are there incentives to remove these contaminants from the waste stream?
Response: The metals in CCA-treated wood can significantly impact the overall quality of municipal solid waste, especially if the waste is incinerated. As for other metals within C&D and MSW waste, there are programs in place to facilitate removal from the waste stream. As a matter of fact the amount of lead and cadmium are decreasing within MSW and C&D landfills. Arsenic is one of the few metals that does not have a program in place.
Comment: Attention should be given to developing strategies to recycle CCA-treated wood products.
Response: If markets are established one must also contend with removing CCA-treated wood from the waste stream.
Alex Gomez: Use of wood in composite materials simply delays the disposal cycle. The composite material will ultimately be disposed at which time the CCA will impact the disposal sector.
Scott Ramminger: Are there methods available to differentiate arsenic containing wood treatment products from non-arsenic containing products?
Response: Yes. The X-ray fluorescence method detects specific metals and it can readily detect arsenic. The chemical stains tested by the research team are not specific to arsenic; however, the team has recently learned about another stain that is arsenic specific. This other stain has not been tested.
George Parris: How much does it cost to sort wood out from the C&D waste stream?
Response: Alex Gomez responded by stating that it is roughly $2 to $2.50 per cubic yard which roughly translates to $10 per ton. Tipping fees for C&D landfills in Florida generally run at about $21 to $28/ton.
Scott Ramminger: How is wood sorted out, especially given that it is commingled?
Response: In actuality not all wood is removed from the C&D waste stream. In Florida, it is estimated that roughly 50% of the wood is sorted out and the remaining 50% is landfilled.
Disposal-end Management, Phase II, Field Study for Chemical Stain
Monika Kormienko summarized the results from the pilot studies at C&D facilties. Three chemical stains were evaluated: chrome azurol, rubeanic acid, and PAN indicator. The objectives of the field studies were to determine whether the chemical stains could be used at C&D facilities to sort CCA-treated wood from other wood types. Three C&D pilot studies have been conducted. For the construction piles evaluated, most of the CCA treated wood was in the form of cut-offs. Most of the treated wood in the demolition pile analyzed was dimensional lumber. The three sites visited contained pre-sorted wood waste piles. The amount of CCA treated wood in these piles was 9%, 10%, and 30% by weight for these facilities. The performance of the stains was discussed. PAN indicator was the quickest chemical to react; however it was subject more interferences than chrome azurol. Interferences were noted with paint and nails. The costs associated with the use of chemical stains and x-ray fluorescence technology were presented. For x-ray fluorescence technology, the cost per ton of waste sorted is dependent upon the size of the C&D facility. For the three facilities that were visited, the estimated costs ranges from $2.50 to $9.25 per ton. Sorting wood waste including separation into treated and untreated wood is less than landfill tipping fees. The cost for using the chemical stains for sorting treated from untreated wood is very high at $25 per ton. Practical applications of the stains include sorting small quantities of treated wood from other wood types and screening fuel quality.
Jim Langdale: It would be worthwhile to focus on treating the ash. Why has the research team deviated from focusing on the ash?
Response: The research team considers that the potential for ash treatment should be further evaluated. The more recent data gathered indicates that metals removal using chemical solvents is more effective that previously thought. Perhaps it can be a focus of future research.
Alex Gomez: It will be very difficult to source separate CCA-treated wood at a demolition job. There may be some potential at a construction site.
Bill Gay: In what form is the waste delivered to the C&D facilities?
Response: Alex Gomez and others answered that it enters the facilities commingled with other waste.
Scott Ramminger: If it is commingled, how do you get all the wood out?
Response: Not all the wood is sorted out. In Florida roughly 50% is landfilled.
Comment: In many cases the wood is ground and intentionally placed in a landfill.
Jim Healey: The data show that we are at the tip of the ice burg concerning disposal issues surrounding CCA-treated wood. There is another smaller project funded by the Center on burning treated wood. Are there efforts to provide more funds to evaluate incineration processes and to remove the metals from the ash?
John Schert: Proposals have been submitted to the Center and the CCA-treated wood project has been short listed in the amount of $100,000.
Jim Healey: A large disposal quantity is coming through. Efforts should focus on getting the metals out of the ash.
Jim Langdale: By the year 2015 it is estimated that 3000 tons of the chemical will be found within the disposal sector and that 660 tons are in the form of arsenic. Will this quantity be in the form of ash?
Response: The 660 tons of arsenic is not specific to the particular form of the arsenic. It may be in the form of ash, mulch, or some other material.
Comment: Should recommend burning treated wood to reduce volume.
Response: It will be difficult to have the existing cogeneration plants permitted as hazardous waste processing facilities.
Diana Davis: Bill Hinkley has mentioned in other meetings that currently there is no waste management practice in place for arsenic. Waste minimization should be addressed. There also has been a controversy associated with elevated arsenic levels at a playground in Gainesville where the soil arsenic concentrations were above the guidance levels for residential uses. What is FDEP's plan to address this?
George Parris: Incorporating C&D wood waste within MSW incinerators will only increase the metals concentrations by a factor of 25.
Dave Dee: All the CCA treated wood cannot go to incinerators because there is not enough capacity to handle it all. The reality of the matter is that cogeneration facilities tried to take clean dry wood. They did not envision a problem with C&D wood waste. The CCA-treated wood waste must be managed in some fashion. What should Florida do? No one will accept putting CCA-treated wood into a phosphate mine as suggested previously. One important issue is that arsenic is being imported into a state that has low background arsenic concentrations. The repercussions of importing the arsenic should be addressed. Questions concerning why there has been a focus on particular research tasks should be directed to Bill Hinkley. The researchers are doing their best to answer the questions raised concerning CCA-treated wood. Lighten-up on the researchers.
Comment: Perhaps the cogeneration plants can handle the CCA-treated wood as a hazardous waste.
Dave Dee: Currently one of the cogenerations plants is bankrupt the second is operating on a marginal basis. If the costs increase for disposal, the second plant will go out of business.
Comment: How about taking one of the cogeneration plants and make it a regional facility for the disposal of CCA-treated wood?
Comment: There would be increased emissions. How can you make that work?
Comment: The C&D industry works on very small profit margins. Only through regulations that provide incentives can it be profitable for sorting and perhaps disposal through cogeneration.
Comment: If the C&D landfills are taken out of business, the cost for disposal in MSW landfills will increase signficantly.
Comment: Perhaps a solution would be to provide incentives for recycling. Perhaps there could be mandates through the legislature. Perhaps a surcharge could be provided to the disposal facility.
Scott Conklin: The key to the problem is identifying the waste stream. We should not write-off sorting at the demolition site. The big blip in the disposal stream is primarily decks which are not difficult to find. The rest of the treated wood in a home is a "drop in the bucket."
John Schert: Sales of CCA-treated plywood for roofing systems appears to have increased. It will be very difficult to sort-out plywood from roofing. I am sure that there are a lot of other uses within a home.
Scott Conklin: The majority of treated wood is in the decks.
Comment: Sorting at the demolition site will require a culture change in demolition activities. The culture is "knock it down and load it up." If regulations are in place that require sorting at the site, many citations will be written.
Diana Davis: I have heard that legislation will be proposed for CCA.
Response: Dave Mason answered by stating that he did not know. Bill Krumbholz mentioned that he had heard that there were discussions that CCA may not be considered a C&D waste and therefore it would have to be disposed in a Class I landfill. David Dee added that this type of change would probably occur through rule-making rather than through the legislature.
Question: Which C&D facilities were studied.
Response: That information is confidential. All facilities were located within Florida.
Disposal-end Management, Phase II, Pyrolysis Evaluation
Helena Solo-Gabriele verbally described the status of the pyrolysis evaluation. Review of the data indicates contradictory information concerning the impacts of temperature on arsenic volatilization during pyrolysis processes. There are currently two known full-scale pyrolysis systems in operation in Europe. One is located in France and called "Chartherm" and the other is run through a copper smelter in Finland.
Question: Has the researcher from France provided additional information to the research team?
Response: Jean Hery, the Chatherm contact, is now communicating with the research team via email. He explained that the reason he could not provide information earlier was because the Chartherm process was being patented. The research team has asked for additional information in the form of publications; however, none of the results are yet available in published form.
Disposal-end Management, Phase II, Sourcebook for Disposal Sector
The rationale for developing the sourcebook was presented by Timothy Townsend. The purpose of the sourcebook is to assist individuals who ultimately must dispose treated wood. Kristin Stook proceeded to describe more details about the sourcebook. The sourcebook will include a list of disposal options for CCA- , creosote-, and pentachlorophenol- treated wood. Targeted waste management facilities include wood burning facilities, construction and demolition debris facilities, and municipal solid waste facilities. Questions included within the questionnaire were listed. A very good response has been received on the questionnaires to date. The sourcebook will be drafted and presented during the Spring 2000 TAG meeting.
Question: There were questionnaires sent to 80 C&D recycling facilities?
Response: The 80 includes recyclers and landfills.
Supplemental Study for Year 3 and Related Research
Helena Solo-Gabriele described the tasks associated with the supplemental study. These tasks include: 1) depletion of Cr, Cu, and As during the service life of CCA-treated wood, 2) quantity of CCA-treated wood used by major industries, 3) laboratory methods for Cr and As speciation, 4) identify laboratory methods for organics analysis associated with alternative chemicals, and 5) replicate TCLP and SPLP results for CCA-treated wood. The focus of the subsequent presentation was on tasks 1 and 5. Methods for task 1 include a literature review, sampling of soils below CCA-treated decks, and analysis of soil samples for Cr, Cu, and As. Naila Hosein presented the soil sampling strategy. A total of nine decks were sampled, three each in the following cities: Gainesville, Miami, and Tallahassee. Surface samples were collected in a grid-like fashion under each deck. A soil core was also collected at each sampling site. Tim Townsend presented the preliminary results of the soil sampling. The background arsenic concentrations at each site were 1 to 3 mg/kg. The arsenic soil concentrations below each deck varied from 5 to 45 mg/kg. A more in-depth analysis is currently underway to better interpret the results.
Ed Zillioux: How were the samples collected along the grid?
Response: They were collected by scraping the upper 1" of soil from the surface.
George Parris: Were the samples collected near posts? This data does not look like Stilwell's data.
Response: We are currently analyzing the data. We have not yet had the opportunity to correlate the location of the sample with their concentration value.
Ed Zillioux: Has the data been correlated against the age of the decks?
Response: We are currently compiling information concerning the age of the decks.
Question: How were the background samples collected?
Response: They were surface samples collected up-slope from the deck.
Question: It was mentioned that the geometric mean of Florida soils is 0.42 mg/kg. How does this compare with the background samples?
Response: The background samples were about 1 to 3 mg/kg.
Question: Any reason as to why the one particular deck was especially elevated?
Response: That deck was recently cleaned. Also, the soil at the site was characterized by a very high organic content.
Comment: There are problems associated with using averages. It is better to look at the distribution than reporting averages.
Tim Townsend: Osmose plans to conduct a deck study. The methodologies used here are consistent with their methods so that results can be compared.
Supplemental Study for Year 3 and Related Research Associated with this Project (continued)
Tim Townsend mentioned that this portion of the presentation will focus on the results obtained from routine leaching tests conducted at the University of Florida and the results from a sister research project that addresses the characteristics of C&D leachate. The title of the presentation was "Issues Regarding the Leaching of Unburned Wood." Tim Townsend described situations during which leaching is of concern, he described the types of leaching tests, and listed the applicable regulatory criteria for arsenic. The results from the TCLP test , which simulates landfill conditions, shows that arsenic leaching is a function of wood sample size. In general the smaller the sample the more arsenic leached per unit weight of sample. Data showed that unburned CCA-treated wood will fail TCLP criteria. The results from SPLP tests, which simulates rainfall, shows that samples of CCA-treated wood will also exceed the 5 mg/L regulatory criteria for arsenic. Results show that the groundwater soil clean-up target levels (GWCTL) are exceeded when CCA-treated wood represents 1% of the wood mixture. The leachates from artificial mulches subjected to SPLP tests is greater than the drinking water standard for arsenic.
Related research indicated that CCA may leach from treated wood under landfill conditions. Two experiments were conducted: one using laboratory columns and another using field test cells filled with C&D waste. Column tests show that arsenic and chromium leaching is a function of time and that the concentrations vary from 0.4 mg/l to 0.05 mg/l. Data collected from a field C&D test cells support the hypothesis that the primary source of leachable chromium and arsenic from these cells is CCA-treated wood. Copper data and other physical-chemical parameters, such as oxidation reduction potential (ORP) and sulfide concentrations were also presented. Issues associated with metal speciation, soil attenuation, and dilution factors were discussed. In summary, it does not take very much arsenic to leach to result in possible disposal limitations under current waste management policies; to fail TCLP 6% of the arsenic must leach; and to exceed GWCTL 0.06% of the arsenic must leach. Future leaching work will include: examining the leaching of weathered wood, further simulation of CCA-treated wood impacts on C&D debris landfills, analysis of metal species, leaching of alternative chemicals, and taking a closer look at C&D debris landfill data.
George Parris: What was the particle size of the CCA-treated wood placed in the columns.
Response: All the waste was ground to 1 inch in size.
George Parris: Please discuss the dynamics of what was happening inside the columns.
Response: Sulpher may impact the mobility of the metals; however, it is also important to note that arsenic followed a similar curve as chloride, which is a conservative tracer.
George Parris: Please list all the parameters that were analyzed in the column studies.
John Schert: What was the volume of waste placed in the field cells?
Response: 100 cubic yards.
Question: How was the water distributed within the lysimeters?
Response: Clean silica sand was placed at the top of the column to distribute the water.
George Varn Jr.: For the TCLP and SPLP on the unburned wood, what size was used during the experiment?
Response: Tests were conducted using various sizes of wood including a 100 g block, a 100 g block cut into 5 pieces, chipped wood was placed through a wood chipper, etc..
George Parris: What was the rate of water flow through the column?
Response: 500 ml/day. Although this rate is higher than the rainfall rate, it is typical of the rate of flow of infiltrated water through a landfill. In a landfill, the infiltration rate will cease during times of no rainfall; in the lysimeter experiments the infiltration rate was kept constant. Applying constant infiltrations rates is a typical protocol for lysimeter studies.
David Dee: Has leachate data from C&D landfills been reviewed? Have hits been observed for arsenic?
Response: Dave Mason mentioned that the FDEP is currently putting together the groundwater data from C&D facilities. Alex Gomez mentioned that no arsenic has been observed in the groundwater wells at his facilities. One of his wells is located at the base of the waste material. Tom Roberts added that there has been testing at his facility since 1992 and he has not observed arsenic either.
The meeting adjourned at 5:00 pm.