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Electrodialytic remediation of creosote and CCA treated timber wastes
2002 - IRG/WP 02-50190
There is a growing concern about the environmental issue of impregnated timber waste management, since an increase in the amount of waste of treated wood is expected over the next decades. Presently, no well-documented treatment technique is yet available for this type of waste. Alternative options concerning the disposal of treated wood are becoming more attractive to study, especially the ones that may promote its re-use. Inside this approach, the electrodialytic process (ED) seems a promising technique for removal of preservative chemicals from treated wood waste. The method uses a direct electric current and its effects in the matrix as the “cleaning agent”, combining the electrokinetic movement (mainly due to electromigration, but also electro-osmosis and electrophoresis), with the principle of electrodialysis. This work reports results from the application of the electrodialytic process to an out-of-service Portuguese creosote and CCA-treated Pinus pinaster Ait. railway sleeper and pole. The behaviour of the process is described and the main results discussed. The average removal rate, estimated in accordance with prEN 12490, for creosote from treated timber waste was around 40 %.. For CCA treated timber waste, experimental conditions that could optimise the process efficiency (e.g. current density, time) were studied. The highest removal rates obtained until now, in our studies, were 93 % of Cu, 95 % of Cr and 99 % of As for sawdust using 2.5 % oxalic acid (w/w) as the assisting agent. For CCA treated wood waste in the form of chips, the best removal rates obtained until now were 84 % of Cu, 91 % of Cr and 97 % of As.
E P Mateus, A B Ribeiro, L Ottosen
Preservative-treated wood as a component in the recovered wood stream in Europe – A quantitative and qualitative review
2004 - IRG/WP 04-50218
Wood preservatives have been used for the protection of timber products in the European market in appreciable quantities for about 100 years. Between the 1960s up to the present day this usage has been particularly noticeable. The aim of this paper is to present quantitative and qualitative data on the volumes of preservative treated wood placed on the market in the UK and Sweden and to evaluate the expected quantities of preservative treated wood coming out of service and into the ‘recovered’ wood stream in the future. Data are presented from a case-study in the UK on CCA (copper, chromium, arsenic) treated timber and projections on likely amounts of this entering the recovery stream up to 2061. It is estimated that in the UK in 2001 approximately 62,000m3 of CCA-treated wood required disposal and that this could rise to about 870,000m3 by 2061. The proportion of CCA-treated timber in all post consumer waste wood in the UK is predicted to rise from about 0.9% in 2001, to about 12.3% in 2061 representing a substantial component of the post-consumer wood stream. In Sweden statistics have been compiled for production of preservative treated wood for many years. The preservatives used for waterborne treatments have also changed significantly over the last 10 years from a dominant role for CCA to alternative, As-free systems. It is estimated that preservative treated wood will represent on average about 5% of the recovered wood flow in Sweden over the next 25-30 years and that this will represent an appearance of about 8000 tonnes of As, 7000 tonnes of Cu and 6500 tonnes of Cr. These data and the possible disposal options for CCA and similar treated wood are considered in a life-cycle thinking context.
R J Murphy, P Mc Quillan, J Jermer, R-D Peek
Disposal of treated wood - Canada
1990 - IRG/WP 3563
It is estimated that treated wood removed from service each year in Canada contains about 16,000 tonnes of creosote, 1000 tonnes of pentachlorophenol and 245 tonnes of CCA or ACA. The amount of CCA treated wood for disposal is expected to increase more than ten-fold by the year 2020. At present, most treated wood is disposed of in landfills, burned (creosote only) or recycled as other products. Other approaches to reduction, reuse, recycling and disposal are discussed.
P A Cooper
Restriction for use and waste management for pressure treated wood - The current situation in Norway
2001 - IRG/WP 01-50175
The Norwegian Environmental Authorities have this winter sent out a draft on restrictions in production and use of heavy metals in preservative treated timber. If it is passed, it will lead to drastic changes in the use of preservatives in Norway from this autumn. The environmental authorities and the preservative industry are both at present discussing waste management for CCA and creosote treated wood.
F G Evans
Experience with an industrial scale-up for the biological purification of CCA-treated wood waste
1997 - IRG/WP 97-50095
The biological purification of CCA-treated wood waste was tested in co-operation of the BFH and the Italian impregnation plant SoFoMe. Chipped poles were infested with the chromium and arsenic tolerant brown-rot fungus Antrodia vaillantii which can transform in the laboratory ca. 90% of the chromium and arsenic into watersoluble salts. These can be leached to 100-200 ppm residual metal content. The fermentation techniques tested will be described and the fermentation success as well as the possible use of the purified material will be discussed.
H Leithoff, R-D Peek
Disposal of CCA treated waste wood by combustion - An industrial scale trial
1996 - IRG/WP 96-50068
Totally 272 m³ (62.7 t) of CCA treated utility poles were chipped and incinerated at Jalasjärvi Gasification Plant. In average the whole batch of chips contained 57 kg of elementary copper, 95 kg chromium and 76 kg arsenic. During the 56 h combustion trial the measured arsenic emission to the air was 76 g in total. Copper and chromium emission was less than 1 g. The condensing water from the cooling unit and the ash from the gasifier were collected and transported to Outokumpu Harjavalta Metals Oy and finally circulated through a copper refinery line.
A J Nurmi
Feasibility study for a dedicated pressure treated wood waste management system
2005 - IRG/WP 05-50224-22
For the creosote treated wood coming out of service, it has been estimated an amount of 200 000 t per year for the next twenty years, and 100 000 t per year afterwards. With a limited number of actors, mainly SNCF (as producer and as user), no importations, and available energy recovery options, it appears possible for setting a dedicated wood waste management system, if the SNCF agrees to. For the CCA treated wood, the amount of it coming out of service will increase and will be much more important, reaching about 400 000 t per year. For setting a voluntary dedicated waste management system might be much more difficult, because the importation is very important (about 50%), the margin of product low and the actors and users are numerous. Over the answer of the question on the feasibility for setting a dedicated pressure treated wood waste management system, this study must allow also define the priority actions to improve the pressure treated wood waste management.
C Cornillier, I Buda, E Heisel, G Labat
Removal of CCA from Spent CCA-Treated Wood
2002 - IRG/WP 02-50192
A novel method for the removal of CCA components from spent CCA-treated wood has been developed. The CCA-treated wood was first converted into liquid in the presence of polyethylene glycol and glycerin at mild temperatures (120 – 150 0C) by using sulfuric acid as catalyst. The resulting viscous liquefied wood was then resolved in acetone/water solvent. The hazardous components (i.e., Cr, As, and Cu) in the solution were then removed through precipitation by addition of complexing agents. It was found that more than 85% of CCA could be removed from spent CCA-treated wood. The detoxified wood can be used as chemicals for the preparation of polyurethane materials and the recovered CCA can be reused in the CCA wood treatment industries.
Lianzhen Lin, Chung-Yun Hse
Bioprocessing preservative-treated waste wood
2000 - IRG/WP 00-50145
Disposal of preservative-treated waste wood is a growing problem worldwide. Bioprocessing the treated wood offers one approach to waste management under certain conditions. One goal is to use wood decay fungi to reduce the volume of waste with an easily managed system in a cost-effective manner. Wood decay fungi were obtained from culture collections in the Mycology Center and Biodeterioration research unit at the USDA-FS Forest Products Laboratory (FPL), Madison, Wisconsin, and from FPL field sites. The 95 isolates had originally been taken from at least 66 sites from around the United States. Isolates were screened in a bioassay (known as the 'choice test') for tolerance to CCA, ACQ, creosote and pentachlorophenol. A tolerant rating was based on fungal growth toward or on treated wood, with 17 tolerant to CCA, 21 to ACQ, 12 to creosote and 5 to pentachlorophenol. Decay capacity of the tolerant isolates was determined as percent weight loss by the ASTM D-1413-76 soil bottle method. We identified 8 isolates for experiments on preservative remediation. Isolates of Meruliporia incrassata and Antrodia radiculosa gave the highest percent degradation of ACQ and CCA-treated wood. Several A. radiculosa isolates and a Neolentinus lepideus isolate grew on creosote-treated wood, but had only a 4-5% weight loss. In this paper we discuss the potential use of decay fungi to degrade or remediate preservative-treated wood.
B Illman, V W Yang, L Ferge
Microbial decomposition of salt treated wood
1993 - IRG/WP 93-50001-22
Specialized microorganisms which are able to convert fixed inorganic preservatives from treated wood into water soluble components are investigated. A number of brown rot fungi like Antrodia vaillantii have been isolated from cases of damage and examined under unsterile conditions with CCA-, CCB-, CCF- and CC-treated wood at retention levels of at least 50% higher than recommended for wood in ground contact. Depending on the kind of fungus, preservative retention, wood particle size, culture conditions and duration Cr and As can be almost completely leached from the treated wood. Cu reacts with oxalic acid to a compound of limited water solubility.
R-D Peek, I Stephan, H Leithoff
Biological detoxification of wood treated with salt preservatives
1992 - IRG/WP 92-3717
The use of microorganisms that are capable to convert chemically fixed inorganic preservative complexes from impregnated wood waste into watersoluble components is investigated. A number of fungi were isolated from deteriorated and initially well-treated wood. They revealed an exceptionally high production of organic acids (pH 2). The fungi were identified and used together with others of the same genus for experiments under non-sterile conditions on a laboratory scale with CCA-, CCB and CC-treated wood at retention levels of at least 50% higher than recommended for wood in ground contact. As a result Cr and As were leached to more than 90% depending on culture conditions, whereas Cu reacts with oxalic acid to a complex with limited water solubility.
I Stephan, R-D Peek
Co-incineration of CCA-treated wood and Municipal Solid Waste in MSWI plant
2005 - IRG/WP 05-50224-19
The Norwegian Association of Energy Users and Suppliers (Norsk Energi) have carried out incineration tests with addition of 10 % by weight CCA-treated wood waste to municipal solid waste in a MSWI plant. The objective with the test was to determine emissions and composition of bottom ash. The incineration test was done at the Klemetsrud plant in Oslo The main conclusions are: -No significant increase in emission of copper, chromium, arsenic and dioxin -Emission of total heavy metals (incl. copper, chromium and arsenic) is much lower than the limit value in the EU directive on waste incineration. -The dioxin concentration in the flue gas was ¼ of the limit value in the EU directive on waste incineration. -The concentration of heavy metals in bottom ash shows levels far below the threshold value stated in the Norwegian regulations for Hazardous waste. The results from the leaching tests suggest that the bottom ash from the incineration with 10 % CCA-treated wood meets the criteria for depositing on landfills for non-hazardous waste.
D Borgnes, B Rikheim
Recycling CCA-treated poles with Charterm
2005 - IRG/WP 05-50224-17
After 10 years of Research and Development, the first “Chartherm” industrial unit is now operating since nearly half a year, thanks to Thermya SA, engineering company, current owner of all the “Chartherm” process Patents and Rights. In accord with the recycling contracts signed with several French major companies, the “Chartherm” plant, located near Bordeaux, recycles every day several hundred CCA treated wooden poles, mixed with some creosote, CCB and CFK treated ones, since the “Chartherm” process do not requires any pre-sorting, being able to process all kinds of treated wood, whichever be the type of contamination of the wood. The "Chartherm" process consists in a “distillation” of wood, at low temperature, in a neutral atmosphere. Each metric ton of wood waste getting into the system produces an average of 300 kg of clean Carbon powder, which has many applications in different industries. All these makes the “Chartherm” process be a very attractive treated wood recycling solution from an environmental, technical and economical point of view.
Electrochemical removal of Cu, Cr and As from CCA-treated waste wood
2001 - IRG/WP 01-50166-18
CCA-treated waste wood poses a potential environmental problem due to the content of copper, chromium and arsenic. This paper presents the results obtained by electrodialytic remediation of CCA-treated waste wood. It is found that more than 90% Cu, and approximately 85% Cr and As was removed from the wood during the remediation. Thereby the concentration of copper in the wood is reduced from app. 426 ppm to app. 25 ppm, chromium is reduced from app. 837 ppm to app.135 ppm and the arsenic content decreases from app. 589 ppm to app. 151 ppm. After remediation the removed metals are collected into liquids. The use of ion exchange membranes to separate the wood from the electrolytes result in a distribution of the metals after remediation that makes the collection of the metals easier, and reuse of the metals, for e.g. new CCA, may be possible.
I V Kristensen, L M Ottosen, A B Ribeiro, A Villumsen
Technologies for the Management of Wood Waste Containing Metals-Based Preservatives
2005 - IRG/WP 05-50224-16
Disposal of the metals from preservative treated wood can occur through two general strategies: “removal and confinement” or “dilution”. The acceptability of each of these two choices is typically dictated through the disposal regulations of a particular region. A considerable amount of research has been conducted to develop new and innovative “removal and confinement” technologies for treated wood waste. These technologies include disposal through bioremediation processes (including use of bacteria and fungi), chemical extraction processes, electro-dialytic treatment, and alternative thermo-chemical processes. “Removal and confinement” strategies will likely require adequate sorting and separation of the waste prior to disposal for mixed waste streams. “Dilution” strategies, which are typically less costly than “removal and confinement” technologies, include the management of treated wood through the regular solid waste stream. In some cases recycling of the wood waste may be allowed for certain re-use and recycling applications. In most regions, management of treated wood as regular solid waste will likely occur through either landfill disposal or through incineration at solid-waste processing facilities. Disposal through incineration will require air pollution control devices to minimize volatile releases and as a result the majority of the metals will accumulate within the ash. If the treated wood waste is co-disposed with other wastes there may be sufficient dilution to provide for a non-hazardous ash, which can be landfilled. Over time disposal of metal-treated wood in landfills (as either unburned wood or as ash) will likely result in the release of the metals from the wood resulting in higher metals concentrations in leachates from landfills. Whether or not this leachate is treated will depend upon whether or not there is sufficient dilution to maintain metals concentrations below certain regulatory thresholds. Thus the choice of suitable disposal options for wood treated with metal-based preservatives is dictated highly by the regulations of a particular region. These regulations are a reflection of the community’s “dilution capacity” and the balance between economics and allowable levels of environmental contamination.
H M Solo-Gabriele, T G Townsend
CCA-treated Wood Disposed in Landfills and Life-cycle Trade-Offs With Waste-to-Energy and MSW Landfill Disposal
2005 - IRG/WP 05-50231
CCA-treated wood as a solid waste is managed in various ways throughout the world. Although some wood is combusted for the production of energy in the U.S., more often than not, CCA-treated wood is disposed in landfills. In other countries, wood, often including CCA-treated wood, is combusted for the production of energy. This paper is presented in two parts. Part I evaluates the impact of CCA-treated wood in three landfill settings: a wood monofill, a C&D debris landfill and a municipal sold waste (MSW) landfill. Part II utilizes the data found in the first part, along with data found in the literature to examine the trade-offs between landfilling and waste-to-energy (WTE) combustion of CCA-treated wood through a life-cycle assessment and decision support tool (MSW DST). The disposal of CCA-treated wood affected all three landfill disposal scenarios increasing concentrations of arsenic and chromium especially. Although the acid-forming phase of the MSW landfill aggressively leached metals, the methanogenic phase was not as aggressive and the impact to the leachate from the CCA-treated wood was less than for C&D debris landfills. Additionally, the decreased impact is a result of the CCA-treated wood comprising a smaller portion of the MSW waste stream by mass. For this reason, and because MSW landfills are lined, MSW landfills were concluded to represent a preferred disposal option over unlined C&D debris landfills. If leachate is collected, leachate treatment in both situations may become more difficult and expensive if concentrations exhibited in this research are observed. Between landfilling and WTE for the same mass of CCA-treated wood, WTE is more expensive (nearly twice the cost), but when operated in accordance with U.S. EPA regulations, it produces energy and does not emit fossil carbon emissions. If the wood is managed via WTE, less landfill area is required, which could be an influential trade-off in some countries. Although metals are concentrated in the ash, the MSW landfill scenario releases a greater amount of arsenic from leachate on an annual basis, but it is more dilute. The ash disposal scenario releases less arsenic from leachate on an annual basis, but concentrates it. The ash disposal releases more chromium on an annual basis. The WTE facility and subsequent ash disposal greatly concentrates the chromium, often oxidizing it to the more toxic and mobile Cr(VI) form. Elevated arsenic and chromium concentrations in the ash leachate may increase disposal costs.
J Jambeck, K Weitz, T G Townsend, H M Solo-Gabriele
Effect of remediation on the release of copper, chromium, and arsenic from particleboard made from CCA treated wood
2001 - IRG/WP 01-50170
This study sought to determine the effect of remediation with oxalic acid (OA) extraction and Bacillus licheniformis fermentation on the release of copper, chromium, and arsenic from particleboard made from remediated wood particles and also investigates durability of the particleboard against white and brown- rot fungi. Particleboard samples were manufactured using untreated, CCA-treated, OA-extracted, and bioremediated southern yellow pine particles. Results shows that oxalic acid extraction and bioremediation by B. licheniformis significantly increased removal of elements from CCA-treated wood particles. The particleboards containing OA-extracted and bioremediated particles showed generally high leaching losses of remaining elements. Exposure of particleboard samples to decay fungi indicated that Gloeophyllum trabeum caused greater weight losses in all samples than Postia placenta. In general, leached samples from all particleboard types had greater weight losses than unleached samples. CCA particleboard samples were the most resistant to fungal degradation.
S N Kartal, C A Clausen
The results of detection on CCA components of the soils contacted with CCA-treated woods - A trial study for the availability of the burial Method as a disposal CCA treated wood waste
1993 - IRG/WP 93-50005
The objecteve of this experiment is to get a knowledge that, when CCA treated wood wastes were buried in a soil as a disposal, the soil would be or not be contaminated by the components of CCA preservatives in wood wastes. The specimens used were cutting logs and chips made of the CCA treated electric pole waste. The soil was buried to the 15 cm depth and the log specimens were set in the soil for parallel direction to the ground line. The chips specimens were placed in the bottomless boxes which were set on the ground floor at 20 cm depth under the ground line. The soil samples were taken from where were directly contacted with the specimens and from where were the nearest places apart from the specimens and were analyzed for CCA components after 6 months and after 6 years since these installation. The results were summerlized as follows. The levels of CCA components in the soil where were directly contacted with the specimens were slightly increased. However that in the soil where were collected over 5 cm far from the specimens were not increased. Therefore, the CCA components in the woods were not contaminated to the soil where were over 5 cm far from the specimens. According to our results, we can consider that the burial method for the disposal of CCA treated wood wastes was an avalable method and also practical possiblity to prevent from environmental contamination.
K Suzuki, H Sonobe
Factors affecting sodium hypochlorite extraction of CCA preservative components from out of service treated wood for recycling
2009 - IRG/WP 09-50263
Significant amounts of chromated copper arsenate (CCA) treated wood products such as utility poles and residential constructions remain in service. There is an increasing public concern about environmental contamination from CCA treated wood when it is removed from service for reuse or recycling, placed in landfills or burned in commercial incinerators. In this paper, we investigate the effects of time, temperature and extractant concentration on chromium oxidation and extraction of CCA-C components from treated wood using sodium hypochlorite. Of the conditions evaluated, reaction of milled wood with sodium hypochlorite for one hour at room temperature followed by heating at 75°C for two hours gave the highest extraction efficiency. An average of 95 % Cr, 99 % Cu and 96 % As could be removed from CCA-C treated milled wood by this process. Most of the extracted chromium was oxidized to the hexavalent state and could therefore be recycled in CCA treating solution. Sodium hypochlorite extracting solutions could be reused several times to extract CCA components from new treated wood samples.
E D Gezer, P A Cooper
Biodegration of treated wood waste by native fungal communities of tropical soil in French Guiana
2012 - IRG/WP 12-50285
Woods have been protected with fungicides for a long time, and the effects of these fungicides on soil after being leached into the ground have turned out to be a true environmental issue. It is in this perspective that we are proposing to study fungal communities of these contaminated woods in a purpose of bioremediation. Most of precedent studies have focused on ability of some Basidiomycetes and white rot fungi to degrade these biocide products. Treated and reference (non-treated) woods samples have been incubated in containers of forest soil in Guyana. The first two samplings of these woods and soils have been realized five months apart. A crop and molecular study allowed us to isolate and identify forty strains of Ascomycetes able to develop on wood and resist xenobiotics. Until now, no Ascomycete was known to resist xenobiotics. Furthermore, a study of fungal communities of the woods and soil were done by D-HPLC and SSCP, and then analyzed by ACP. According to these analyses, biocides are leached in the soil and have an impact on these fungal communities, which are different depending on time of sampling and the way wood is processed.
A Zaremski, L Gastonguay, C Zaremski, F Chaffannel, J Beauchêne, G LeFloch
Possible regulatory status of treated wood waste and implications
1998 - IRG/WP 98-50101-07
In relation to the European Community or the French regulations, treated wood waste can get two different regulatory status: <<recycled product or fuel>> or <<waste>>. Then, into the waste status, two categories are possible for these residues: <<domestic waste and assimilated>> or <<hazardous waste>>. These different status and categories are important for the environmental issue of treated wood waste management. But they also can have strong economical implications, linked to the waste management cost on one hand and on the materials image on the other hand. On the basis of the EC regulations, up to now, no treated wood waste is namely quoted as <<hazardous waste>>. However, through the classification criteria defined by different EC directives, creosote or heavy metals treated wood waste could be to considered that way. The technical arguments for such a classification and the practical implications are discussed.
Termite resistance of pine wood treated with chromated copper arsenates
1997 - IRG/WP 97-30128
Two four-week, no-choice laboratory tests were performed with CCA-treated southern yellow pine and radiata pine against Formosan subterranean termites, Coptotermes formosanus. CCA retentions as low as 0.05 kg/m3 (0.03 pcf) provided protection from all but light termite attack (rating of 9 on a 10-point visual scale). Similar and consistent light attack on wafers containing retentions as high as 6.4 kg/m3 (0.4 pcf), coupled with complete termite mortality, demonstrates that the mode of action of CCA treatments relies upon toxicity rather than having any repellent effects against termites.
J K Grace
Application of radio frequency heating to accelerate fixation of CCA in treated round-wood
1999 - IRG/WP 99-40133
The potential of radio frequency heating to accelerate the fixation of chromated copper arsenate (CCA) in treated round-wood was assessed. Pre-dried Douglas-fir and western red cedar round-wood sections were pressure treated with CCA in a pilot plant retort, after which they were placed individually in a pilot radio frequency (RF) chamber. Based upon the color reaction of chromotropic acid with hexavalent chromium and the quantitative assessment using diphenyl carbazide, fixation was achieved in less than 6 hours. During heating, the temperature at various locations inside the pole sections was monitored by fiber-optic thermocouples. The moisture profiles before, and after fixation, were also recorded. Further studies will examine other benefit of RF heating, including a) sterilization, and b) rapid drying of round-wood with minimum check formation.
Fang Fang, J N R Ruddick
Effect of water repellents on leaching from CCA treated wood
1995 - IRG/WP 95-50044
CCA treated fence boards brushed with a water repellent finish had consistently lower leaching losses of all CCA components compared to the rate for matched samples without the water repellent. These results are after 12 cycles of simulated rainfall in the laboratory (1800 mm rainfall total) and four months of natural rain exposure in Toronto.
P A Cooper, R MacVicar
Rates of emission from CCA-treated wood in the marine environment: measurement, modelling and requirements for further research
2001 - IRG/WP 01-50166-12
Accurate estimates of rates of emission of leachate from preservative treated wood are crucial for realistic predictions of the environmental impact of its use in maritime construction. Estimates are available for some commonly used preservatives, but these vary widely. Though variable, these measurements suggest that emission generally decreases exponentially with time. Part of the variation is due to differences in methodology employed. Physical and chemical characteristics of the seawater used (e.g. temperature, salinity, pH and oxygen content) affect emission rate. So too do the specifics of the treatment process especially the preservative formulation used, and pre- and post-treatment handling of the wood. The nature of the treated wood samples is also important, with misleadingly high estimates being obtained from samples with unrepresentatively high proportions of cross-cut surfaces. A suggested strategy for developing an informative and standardised methodology is discussed. To form useful models of impacts of leaching, emission rates need to be considered in conjunction with site-specific information regarding a) water exchange rates between the area where leaching occurs and the sea, and b) the extent of partitioning of leachate between the water column, biota and sediment. The risk of environmental impact may be reduced by modification to treatment procedures and by careful planning of installation.
S M Cragg, C J Brown, R A Albuquerque, R A Eaton