Minutes of the Technical Advisory Group (TAG)

Meeting held December 11, 1998 in Gainesville, Florida

Disposal of CCA-Treated Wood: Existing and Alternative Management Options

Agenda for TAG Meeting

1. Welcome
2. Introduction
3. Summary of Research Plan for Year 2 Solo-Gabriele
4. Presentation of Research Results to Date
        -Sorting Study, Work with stains and ASOMA Equipment Solo-Gabriele/Kormienko
        -Solvent Extraction, U.Miami Solo-Gabriele/Calitu
        -TCLP/SPLP, U.Florida Townsend/Messick
5. Plans for next year Solo-Gabriele/Townsend
        -Phase I: Alternative Chemicals
        -Phase II: Disposal-End Management
        -Field Demonstration of Sorting Technologies
        -Testing a Commercially Available Pyrolysis System
        -Sourcebook for Disposal Sector
6. Discussion
7. Adjourn

Attendees in Gainesville:

Kevin Archer, Product Development Manager, Chemical Specialties Inc., Charlotte, NC

Vandin Calitu, Graduate Student, University of Miami, Coral Gables, FL

Kenneth Cogan, Technical Representative, Hickson Corporation, Conley, GA

David Dee, Attorney, Landers & Parsons, Tallahassee, FL

Jim Gabbert, Gabbert and Meyer, Sarasota, FL

Bill Gay, Wood Preserving Group Manager, Langdale Forest Products Co., Valdosta, GA

Monika Kormienko, Graduate Student, University of Miami, Coral Gables, FL

Bill Krumbholz, Environ. Manager, Dept. of Environ. Protection - Solid Waste Div., Ft.Myers, FL

Lisa Martin, Engineer II, Florida Department of Environmental Protection, Tallahassee, FL

Brian Messick, Graduate Student, University of Florida, Gainesville, FL

Mike Provenza, Environmental Health and Safety Manager, Robbins Manufacturing, Tampa, FL

Chih-Shin Shieh, Director of the F.I.T., Research Center for Waste Utilization, Melbourne, FL

Helena Solo-Gabriele, Assistant Professor, University of Miami, Coral Gables, FL

August Staats, Mngr. Environ. Services, Osmose Wood Preserving Division, Griffin, GA

Don Surrency, Manager of Plant and Sales, Koppers Industries Inc., Gainesville, FL

Timothy Townsend, Assistant Professor, University of Florida, Gainesville, FL

George Varn, Jr., Project Manager, Varn Wood Products, Hoboken, GA

A group of students from the University of Florida also attended. These students were: Tim Franklin, Vicky Gou, Yong-Chul Jang, Sue Lee, Scott Sheridan, Paul Vaucusen, and Billy Weber

Attendees in West Palm Beach via Teleconference at Florida Power & Light (FPL) facility:

Bill Benton, Environmental Coordinator, FPL Distribution Environmental, Daytona, FL

Diana Davis, Attorney, FPL Law Department, Juno Beach, FL

Keith Drescher, Environmental Specialist, FPL Distribution Environmental, West Palm Beach, FL

Jerry McMullan, Product Engineer, FPL Distribution Engineering, West Palm Beach, FL

Dan Rawson, Logistics Operations Supervisor, FPL Distribution Environmental, West Palm Beach, FL

Susan Sweeney, Bioanalyst, FPL Materials Management, West Palm Beach, FL

Warren Tittle, Environmental Permit Specialist, Distribution Environmental, Sarasota, FL

Ed Zillioux, Environmental Services, Juno Beach, FL

The meeting began at 10:05 am and ended at 12:20 noon

1. Welcome

Dr. Helena Solo-Gabriele welcomed all TAG members and invited guests to the meeting.

2. Introduction

Individuals present in Gainesville and at the remote site in West Palm Beach introduced themselves by stating their name and affiliation.

3. Summary of Research Plan for Year 2

Dr. Helena Solo-Gabriele described the format for the morning's presentations which were to occur in three parts. First a broad overview of this year's project was to be presented, followed by a more detailed description of the research results to date and by a description of plans for next year. The research plan for the current year (year 2) was motivated by the results of year 1 activities which found that the quantities of CCA-treated wood waste would increase in the near future, sorting of CCA-treated wood from untreated wood is very limited at construction and demolition (C&D) recycling facilities, and the primary pathway for the disposal of CCA-treated wood is energy recovery. A conclusion from these findings is that ash quality at wood burning facilities will likely degrade further. Given these concerns the objectives of the current study were formulated. These objectives include: evaluate the leaching characteristics of CCA-treated wood ash (Phase I), assess two sorting technologies, chemical stain and energy dispersive x-ray fluorescence (EDX), for separating treated wood from untreated wood (Phase II), and evaluate options for Florida with respect to the practical limitations (Phase III). The timeline and technology transfer plan for the study were presented. The presentation closed with a description of anticipated benefits.

4. Presentation of Research Results to Date

Sorting Study, Work with Stains

Dr. Solo-Gabriele introduced Monika Kormienko who proceeded to describe the results of work with chemical stains. The chemical stains tested included chrome azurol, rubeanic acid, and PAN indicator. The formulation for chrome azurol was modified to improve the rate at which the color change occurred. With the new formulation, which is alcohol based, the reaction is immediate. The original formulation for rubeanic acid required two separate stains; the new formulation requires only one. Distinct color changes were observed for all three chemical stains. This was observed for whole pieces of wood, shredded wood samples prepared in the laboratory, and for most field samples collected from C&D recycling facilities. Chrome azurol is the chemical of choice for unshredded samples, and chrome azurol and PAN indicator were of the best indicators for shredded pieces of wood. The stains were found suitable for most but not all recycled wood waste. Recycled wood waste which contained a lot of soil or fibrous material did not stain well. The stains can be used to sort small quantities of treated wood from untreated wood and for screening fuel quality. Plans for next year include the publication of results of the stain tests and EDX and informing C&D recyclers of the technologies available for sorting treated from untreated wood.

Sorting Study, Work with ASOMA

Dr. Solo-Gabriele mentioned that work with ASOMA began before the trip to the headquarters of the company located in Austin, Texas. This early work involved an exchange of samples and results prior to the trip. Dr. Solo-Gabriele then introduced Monika Kormienko who began by describing the theory of EDX and by describing why ASOMA Instruments was chosen for the study. ASOMA Instrument Model 400 was described in greater detail, which was the instrument used at ASOMA headquarters to evaluate whether EDX technology was suitable for an on-line sorting system. Experiments conducted at ASOMA were designed to determine the minimum analysis time, the best metal for analysis, spacing between the sensor and wood, and the detection limit for the technology. Conclusions from these experiments were that the minimum count time was 2 seconds; however, the true minimum is likely shorter for an on-line system since time will not be needed for the sensor shutter to open and close. The best indicator metal was arsenic. The minimum detection limit for the instrument is a 3% mixture of CCA-treated wood. Detection of whole pieces of wood (0.25 pcf) is possible at a 1 inch distance. This distance is adequate whether or not a plastic shield is used to protect the sensor. The advantages of EDX include no sample preparation, no alteration or contamination of the wood being analyzed, low maintenance, and no waste generation. The primary disadvantage is cost; an on-line system will cost between $20,000 to $100,000.

Question: Kevin Archer asked why other EDX manufacturers were not asked to participate. He mentioned that Oxford analyzers generate a signal from accelerated electrons rather than from a radioactive source. From a licensing point of view, there may be some advantages in using the Oxford equipment.

Response: ASOMA was chosen because it is the largest supplier of EDX equipment for the wood treating industry. They were very cooperative when they were first contacted and therefore the research group chose to collaborate with ASOMA. Our work with ASOMA does not necessarily rule out work with other companies. The research group will evaluate potential advantages of using equipment from other manufacturers.

Question: Kevin Archer expressed a concern about the addition of a chemical to the wood during the staining process.

Response: The organic portion of the stains should not represent a problem if the wood is incinerated properly. The research team will investigate this issue further and will report on the results at the next meeting.

Question: Jim Gabbert expressed a concern about the large-scale application of sorting technologies, especially given the large range of wood sizes and shapes and the immense quantities of wood recovery at some facilities.

Response: The research team recognizes that although EDX technology appears feasible, sample introduction will be one of the most challenging aspects of implementing the technology.

Questions: Don Surrency asked about how wood is sorted at C&D recycling facilities and what is done with the CCA-treated wood that is sorted out.

Response: Jim Gabbert mentioned that wood at his facility is sorted manually. Vegetative waste is first separated from dimensional lumber. Treated portions of dimensional lumber are separated from untreated portions by visual inspection. Jim Gabbert also mentioned that the treated wood is sold at low cost for reuse purposes. The market for used treated poles appears to be good.

Question: George Varn asked about whether the 2 second count time could be further reduced. A 2 second analysis time would not be conducive to large-scale recycling.

Response: Engineers at ASOMA Instruments indicate that the "true"count time for an on-line system is likely a fraction of a second. During analysis using the Model 400T, the sensor shutter opens and closes thereby artificially increasing the count time.

Solvent Extraction, U. Miami

Dr. Solo-Gabriele introduced Vandin Calitu who described the results of the solvent extraction study. Sample preparation involved shredding wood using an industrial shredder and incinerating at the Florida Power and Light facility. Ten extractions were conducted ranging from distilled water to concentrated acids. All extractions were followed by total recoverable metals as per EPA method 3050b. Extractions were conducted on eight samples including untreated wood, wood treated at 0.25 pcf, 0.60 pcf, and 2.50 pcf, a weathered wood sample, followed by samples collected from three different C&D recycling facilities. Metals analyses for chromium and copper is proceeding as planned on a flame atomic absorption spectrometer. The arsenic analyses will be conducted shortly using a colorimetric method. Results from total recoverable metals show that the amount of chromium extracted increases from untreated wood, C&D recycled wood waste, 0.25 pcf, 0.60 pcf, to 2.5 pcf CCA-treated wood. For the 2.5 pcf sample, of the total weight of ash, 9% is extractable as chromium. Extractions using the non-acid solvents indicate that copper was more difficult to remove than chromium. A maximum of 20% of the total recoverable copper was removed using hydroxylamine hydrochloride. Between 80 to 99% removals were observed for chromium using distilled water alone for the ash collected from C&D recycling facilities. Such high removals were not observed for wood treated at the high retention levels. Citric acid showed the best performance among the acids with its ability to remove most of the copper and chromium from C&D wood ash samples.

Question: Dr. Shieh described his experience with sequential extractions of metals from treated wood ash. His results show that chromium is not likely removed with distilled water.

Response: The data are preliminary and are currently being evaluated. However, the results at this point show that chromium can be easily extracted from C&D recycled wood ash. Discussions continued concerning incineration temperatures and % ash recoveries in an attempt to reasons for these differences. Dr. Solo-Gabriele agreed to discuss the results further with Dr. Shieh.

TCLP and SPLP, U. Florida

Dr. Townsend discussed the toxicity characteristics leaching procedure (TCLP) and the synthetic precipitation leaching procedure (SPLP). He described the analytical details as well as the application and interpretation of the results. He then introduced Brian Messick, who described the experimental design for the ash samples. The experimental design involved separating the sample into two size fractions, one larger that 4.75 mm and another smaller than 4.75 mm. Each size fraction was subjected to TCLP, SPLP, and total recoverable metals. Preliminary tests were conducted to determine the proper leaching solution for TCLP analysis. The presentation also included a discussion of the pH after extraction and a discussion of analytical procedures for metals determinations. To date a total of 115 leaching tests have been conducted, 200 digestions have been completed, and most samples have been analyzed for copper. Results to date show that TCLP and SPLP concentrations for copper are less than 1 mg/L for untreated wood ash and for ash produced from C&D waste wood. The highest values, greater than 40 mg/L, were observed for ash produced from 0.60 pcf CCA-treated wood. Remaining tasks include completing chromium and arsenic analyses on leachate digestates, digest and analyze samples for total recoverable metals, and data analysis.

5. Plans for Next Year

Dr. Solo-Gabriele presented the plans for next year's research titled, "Chemical Alternatives and Improved Disposal-End Practices for CCA-Treated Wood." The pre-proposal has been approved by the Florida Center for Solid and Hazardous Waste Management. The full proposal is due at the beginning of 1999. Next year's study consists of two phases: Phase I, Alternative Chemicals, and Phase II, Disposal-End Management. Alternative chemicals considered for next year's study are waterborne preservatives that contain no arsenic, chromium, or zinc and which have standards provided by the American Wood Preservers' Association. Alternative chemicals initially considered include: alkyl ammonium compound, ammoniacal copper quat, borates, copper azole, ammoniacal copper citrate, and copper dimethydithiocarbamate. Evaluation of these chemicals will include feedback from the chemical manufacturers, wood treaters, and from large end-users of CCA-treated wood. Work on disposal-end management will focus on field demonstrations of sorting technologies, an evaluation of available pyrolysis systems, and developing a sourcebook for the wood disposal sector. A final report along with a draft copy of the sourcebook will be available by March 2000. The presentation closed with the budget for the study and with a list of practical benefits from the research.

Question: David Dee asked about how best to accomplish sorting from a practical perspective. He also mentioned that there are different uses of recycled wood waste other than cogeneration.

Response: It is much easier to sort whole pieces of wood than a mixture of shredded wood pieces; thus sorting should be accomplished at the C&D recycling facilities prior to shredding the wood. Dr. Townsend further added that sorting should be promoted at construction sites. Jim Gabbert and Dr. Chih-Shin Shieh added that another promising alternative to cogeneration is using wood waste to produce colored mulch. Apparently there is a growing market for this recycled material.

Video-tape of ASOMA on-line sensor for sorting PVC and PET plastic bottles

A short video tape was shown that illustrates the use of EDX in sorting plastic bottles based upon their chloride content. A similar system could be designed to sort treated wood from untreated wood based upon arsenic content.

Comment: Sample introduction to the EDX sensor will be a challenge.

The next TAG meeting has been scheduled for March 26, 1999 in Miami, Florida.