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Disposal of Pressure Treated Wood in Construction and Demolition Debris Landfill
2005 - IRG/WP 05-50235
Pressure treated wood is often disposed in landfills in the US, very frequently in construction and demolition (C&D) debris landfills. C&D debris disposal facilities in many states are not equipped with liner systems to protect underlying groundwater. In this paper, issues associated with the disposal of metal-containing treated wood in C&D debris landfills are discussed. C&D debris landfills can be biological active systems, dominated by the activity of sulfate reducing bacteria. The leachate is characterized by relatively low biodegradable organic compound concentrations, high salt concentrations, a neutral pH, and a moderately to strongly reducing environment. Simulated landfills containing CCA-treated wood often show relatively high concentrations of As and Cr, but only minimal concentrations of Cu. Cu-based preservatives such as alkaline copper quaternary (ACQ) also show minimal copper leaching, suggesting that disposal of Cu-based wood preservatives posees minimal impact to groundwater from Cu leaching.
T G Townsend, B Dubey, J Jambeck, H M Solo-Gabriele


The Disposal of CCA-Treated Wood in Simulated Landfills: Potential Impacts
2003 - IRG/WP 03-50198
Landfills are typically where CCA-treated wood is currently disposed, and will likely continue to be the primary form of management in the future. It has been shown that arsenic, copper and chromium leach from CCA-treated wood in certain situations; however, the impact of the disposal of CCA-treated wood on landfill leachate is currently unknown. The objective of this research is to examine the potential effect of the disposal of CCA-treated wood on landfill leachate characteristics. Disposal in C&D debris landfills, the facilities where CCA-treated wood is typically managed in Florida, United States (U.S.), was examined. In other states, CCA-treated wood may go to municipal solid waste (MSW) landfills, which are required to have liners and leachate collection systems under U.S. law. Thus, the MSW landfill disposal scenario was examined as well. Finally, the disposal scenario of CCA-treated wood in a monofill, or a landfill where only CCA-treated wood is disposed, was explored. The effect of CCA-treated wood on leachate in each of these three scenarios was examined by creating simulated landfill environments each containing CCA-treated wood. Six lysimeters (simulated landfill columns), two for each disposal scenario, were constructed and operated; both control lysimeters (no CCA-treated wood) and experimental lysimeters containing CCA-treated wood were constructed for the three scenarios. Natural and simulated rainwater was allowed to infiltrate and percolate through the waste in the lysimeters creating leachate. Leachate was generated by the lysimeters and analyzed for arsenic, copper and chromium concentrations and general water quality parameters.
J Jambeck, T G Townsend, H M Solo-Gabriele


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


Recycling of CCA treated wood in the US
1998 - IRG/WP 98-50101-08
The production of CCA treated wood has increased dramatically in recent years. Previous estimates of the volume of treated wood to be removed were based on the assumed service life of the material, generally 20 to 25 years. This study based on a survey of contractors installing treated decks, determined that the actual service life of these decks is much shorter than their assumed functional service life. Home owners replace decks for various reasons beyond the soundness of the wood, including many reasons related to the look, appearance, and style of the deck. These new estimates of CCA treated wood likely to be removed in the near future greatly increases the volume destined for disposal primarily in landfills. This increases the pressure on these sites and may make competing disposal methods more attractive.
J McQueen, J Stevens, D P Kamdem


A Prediction of Arsenic Groundwater Concentrations Influenced by Construction and Demolition Debris Landfills in Florida Containing CCA-Treated Wood
2006 - IRG/WP 06-50242
Groundwater fate and transport models can provide an indication of the potential impacts of arsenic from the infiltration of leachate from unlined C&D debris landfills containing CCA-treated wood. A solute transport model, Migration of Organic/Inorganic Chemicals (MYGRT), was chosen to predict groundwater contaminant concentrations at specified locations from a hypothetical source (C&D landfill) that contains CCA-treated wood. MYGRT simulates a single contaminant, generated from a surface source, migrating downward through the unsaturated soil layer, mixing with the underlying groundwater, and then migrating horizontally downgradient through the aquifer. The software incorporates the processes of advection, dispersion and retardation. Because of the slow and complex transport mechanisms involved, groundwater impacts may not be observed for many years. A small fraction of the arsenic from the CCA-treated wood disposed in C&D debris landfills was simulated as leached (17.1%). Although hundreds of years later, exceedances of current and potential groundwater cleanup target levels were predicted.
J Jambeck, T Townsend, H Solo-Gabriele


Danish wood preservatives approval system with special focus on assessment of the environmental risks associated with industrial wood preservatives
2001 - IRG/WP 01-50166-01
The following is a description of the procedure used by the Danish Environmental Protection Agency to assess the environmental risks associated with preservatives used in the pressure impregnation of wood. The risk assessment covers issues considered to be of significance for the environment and which are adequately documented so as to allow an assessment. Such issues are persistence and mobility in soils, bioaccumulation and the impact on aquatic and terrestrial organisms. Unless required in special circumstances, the assessment does not apply to birds and mammals as the normal use of preservative treated wood is not expected to involve any noteworthy exposure of these groups. Approval of wood preservatives will be based on a general assessment of the environmental risk associated with the normal use of wood treated with the preservative in a realistic worst case situation. The assessment may address other aspects such as disposal and total life cycle.
J Larsen


Management of the wood and additives wastes in the wood processing industries: Problematics and technical answers review
1996 - IRG/WP 96-50073
Management pathways for pure wood subproducts are well known and used; but as soon as additives like preservatives, glues, varnishes or coatings are present within the wood wastes, their disposal or valorization becomes more tricky. The different kinds of mixed wood wastes of the wood processing industries, from the sawmill to the furniture manufacture, are identified herewith and their diversity is examined. These wastes can be classified according to their danger characteristics, taking into account the type of additives, their concentration, their availability for the environment, the physical state of the waste. Different disposal pathways are then considered. Combustion, with the possibility of energetic valorization seems the best answer for a major part of these wastes. But this is only possible if good combustion conditions are defined, so that no harmful products are emitted. Moreover, these conditions must be affordable on the technical and economical point of view. Then, some wastes cannot be burned in such a simple way, and need a larger approach, which is presented in this document.
S Mouras, G Labat, G Deroubaix


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.
G Deroubaix


The collaborative developement of soil acceptance criteria for timber treatment chemicals in New Zealand
1995 - IRG/WP 95-50040-34
In New Zealand, the issue of potential contamination on timber treatment sites arose in the late 80&apos;s due to the long history of use of PCP by the industry. One of the recommendations from the task group set up to investigate the issue was the development of a set of acceptance criteria to define trigger levels for remediation. A technical group from the government, industry and regional councils supported by experienced environmental consultants was formed by the Ministry for the Environment to prepare the criteria. Guidelines for soil and landfill criteria were drafted covering the commonly used preservative products based primarily on human health risk exposure. Guidelines were also developed for specific beneficial uses where other risk exposures may dominant. The guidelines have been peer reviewed and issued in draft form for public comment. Several benefits have flowed from this process namely, a relatively short timeframe, low cost, multiple party ownership, practicality of application and ease of administration.
H C Boyd


Fiji wood preservation regulations
1980 - IRG/WP 3138
A S Alston


Environmental issues: Messages for the wood preservation industry
1985 - IRG/WP 3353
A review of the origins and structure of environmental legislation throughout those territories of the world where wood preservation is a major industry is given. The implications of media, industry and legislation interaction is discussed and suggestions made as to the key issues the wood preservation industry should concentrate its attentions on in the immediate future.
D G Anderson, P Waldie


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


Wood preservation and the environment: A Canadian perspective
1990 - IRG/WP 3577
The non-pressure (surface) and pressure treatment of wood impacts on the environment in four ways. These are: through the production of treated wood at sawmills and pressure treating facilities; during the storage of treated wood prior to use; when the pressure treated wood is placed in service; and finally, when the treated product reaches the end of its useful life and must be disposed. By reference to current and past Canadian wood preserving practices, the impact of concern by environmentalists on future directions for the wood preserving industry is reviewed. "Information gaps" are identified, which must be filled if the general public&apos;s perception of wood preservation as being beneficial to society is to be maintained. The need for internationally agreed criteria for the approval of new preservatives is also identified.
J N R Ruddick


Protection of Ochroma pyramidale from fungal decay with N,N-napthaloylhyroxylamine
1998 - IRG/WP 98-30182
Fungal decay of wood in service results in billions of dollars (U.S.) in losses annually. Recent environmental restrictions, both U.S. and international, are limiting and eliminating the use of broad-spectrum, heavy metal biocides for wood preservation. Restrictions result primarily from problems with disposal. New wood preservatives need to be developed and tested which specifically target key elements in the sequence of fungal decay mechanisms. Our laboratory has been experimenting with chemicals which inhibit pectin hydrolysis during incipient brown-rot and white-rot decay in southern pine sapwood (Inter. Biodeter. Biodegrad. 39:103). In the present paper these results are extended to include the tropical hardwood Ochroma pyramidale (balsa). Balsa blocks (24x18x12mm) were exposed to two brown-rot fungi and one white-rot fungus in ASTM soil block tests for 10 weeks. CCA (6.4 km/m3 ) was compared with the calcium binding agent N,N-napthaloylhydroxylamine (NHA; 1.6, 3.2 & 6.4 km/m3 ) in leached and unleached blocks. CCA protected balsa with minimal weight loss (> 7.4%) with no leaching effects. NHA (6.4 km/m3 ) protected balsa (0.3-1.2%) weight loss but leaching raised the weight losses to 25% with the brown-rot fungus Tyromyces palustris. We conclude that NHA can protect balsa against G. trabeum and T. versicolor with comparable efficiency to CCA (leached and unleached) but not T. palustris.
F Green III, T L Highley


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


Role of Global Cooperation in Wood Protection for Conserving Forest Resources
2007 - IRG/WP 07-50249
The current uses of treated wood are discussed along with the emerging concerns for continued use of these products. The issues of new chemicals, treatments for wood based composites, migration of chemicals from treated wood, and the disposal of these products at the end of their useful life are all outlined. The potential for the IRG to serve as the focus for research discussion as well as collaborative projects to help enhance wood performance are discussed.
J J Morrell, G Deroubaix


Second international symposium on wood preservation "The challenge safety-environment" 8-9 February 1993, Cannes-Mandelieu, France
1993 - IRG/WP 93-50001
Contains the following 34 Documents (IRG/WP 93-50001/1 - IRG/WP 93-50001/34) and 4 abstracts: A methodology for the life-cycle assessment of treated timber products (IRG/WP 93-50001/1) Initial results and observations of a model system to assess the efficacy and environmetal impact of preservative treated wood (IRG/WP 93-50001/2) Borates as wood preservatives - an environmental, health and safety perspective (IRG/WP 93-50001/3) The shower test method. A leaching test for assessing preservative losses from treated timber under simulated open storage conditions (IRG/WP 93-50001/4) A comparative study of CCA type C and B treated poles in service (IRG/WP 93-50001/5) Laboratory experiments on aerial emissions from wood treated with wood stains (IRG/WP 93-50001/6) Depletion of preservatives from treated wood: Results from laboratory, fungus cellar and field test (IRG/WP 93-50001/7) Modelling of PCP migration in the environment: Feeding the models with laboratory data (IRG/WP 93-50001/8) Programme d&apos;études sur le pentachlorophénol (IRG/WP 93-50001/9) Système informatisé d&apos;aide à la décision pour la gestion de la migration du pentachlorophénol dans l&apos;environnement (IRG/WP 93-50001/10) Health hazards and environmental aspects when using Cu-HDO-containing wood preservatives in vacuum pressure plants (IRG/WP 93-50001/11) On-site test for indicative determination of leaching of components of preservatives from treated timber (IRG/WP 93-50001/12) Assessment of losses of wood preservatives from treated wood by leaching into the environment (IRG/WP 93-50001/13) Le séchage arificiel du bois. Simple opération de traitement du metériau ou méthode douce de préservation? [Wood kiln drying. Simple process of material treament or soft method of preservation?] (IRG/WP 93-50001/14) Social and economocal impact of an extension of service life resulting of an adequate preventive treatment. Application to wooden components used in urban areas with a high density of population (IRG/WP 93-50001/15) Extending the useful life of creosoted electricity distribution poles in service (IRG/WP 93-50001/16) Utilisation industrielle du bois. Préservation de la matière première par des utilisations rationnelles successives de ses propriétés (IRG/WP 93-50001/17) The potential for reuse of treated wood poles removed from service (IRG/WP 93-50001/18) Development of a commercial-scale CCA chemical sludge recycling system (IRG/WP 93-50001/19) Persistance of active ingredients in treated wood (IRG/WP 93-50001/20) Solidification - A viable option for the safe disposal of CCA treatment plant wastes (IRG/WP 93-50001/21) Microbial decomposition of salt treated wood (IRG/WP 93-50001/22) Délavabilité de bois ronds traités avec un sel CCA dans des conditions réelles de stockage. Incidence pratique de la fixation accélérée par étuvage. Impact effectif sur l&apos;environnement (IRG/WP 93-50001/23) The microbiological treatment of chlorophenolic preservative in spent utility poles (IRG/WP 93-50001/24) The fate of salt preservatives in facility yard soils and decontamination of soils and drainage waters (IRG/WP 93-50001/25) Decomposition of biocides in aqueous media cases of MTC and TCMTB (IRG/WP 93-50001/26) Quantification des émanations de substances dans l&apos;air ambiant a partir des bois traités (IRG/WP 93-50001/27) A voluntary system to control the usage of wood preservatives in Austria (IRG/WP 93-50001/28) Health and safety in use of antistain chemicals (IRG/WP 93-50001/29) Dutch work programme for environmental measures in wood preserving industry (IRG/WP 93-50001/30) Dutch national environmental policy strategy (NMP): Implications throughout the life cycle of treated timber and for the Dutch preservation industry (IRG/WP 93-50001/31) Eco-tax - A new threat for wood preservation? The Belgian experience (IRG/WP 93-50001/32) Inventaire des "déchets" ou produits connexes de la filière bois (IRG/WP 93-50001/33) Trends in environmental management in industry. Implications for wood preservation activities (IRG/WP 93-50001/34)
Anonymous


Rapid analytical methods for wood waste - An overview
1998 - IRG/WP 98-50104
The proper handling of wood after service is a today&apos;s problem. Untreated wood could be reused or may be used as fuel. For treated wood special care is demanded to avoid environmental impacts. Thus, analytical methods are requested to detect rapidly whether and to what extend wood is contaminated, covering a wide spectrum of organic and inorganic agents used during the last 50 years. Traditional methods can not meet today&apos;s requirements due to their time consumption or high detection limits. Modern analytical techniques are widely used in research and industry, but their application for wood waste is still difficult due to the complex and differing organic structure of wood. An overview on analytical methods, their chances and limits will be given. In particular it is reported on a joint research programme initiated by the German Environment Foundation. The program aims at the development of a single or combined method that is able to detect both, organic and inorganic contaminations in wood in industrial scale. This technique shall be suitable for the entrance control at waste disposal sites as well as the controlled demolition. The most promising techniques for fast analises are based on Laser-Plasma-Atomic-Emmission-Spectroscopy for inorganic agents and Ion-Mobility-Spectroscopy for organic agents.
A Peylo, R-D Peek


Optimum growth conditions for the metal-tolerant wood decay fungus, Meruliporia incrassata TFFH 294
1999 - IRG/WP 99-50142
There is a worldwide need for alternative methods for the treatment and disposal of CCA-treated waste wood. Illman and Highley (IRG/WP 96-10163) reported the isolation of a unique strain of Meruliporia incrassata (TFFH 294) with tolerance to CCA. The strain is capable of degrading CCA treated waste wood, giving a 40% weight loss in the ASTM soil block test. The strain is an ideal candidate for degrading CCA-treated waste wood, which is accumulating in landfills at a rapid rate. In this study, we report the optimum growth conditions of the fungus, including the effect of chemically defined liquid media, growth temperature, light sensitivity, oxygen requirement and nutrient supplements. The results of a metal-tolerance test and SEM evidence of fungal growth on CCA-treated wood are given to support M. incrassata TFFH 294 tolerance.
V W Yang, B Illman


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 &apos;choice test&apos;) 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


Utility pole recycling and disposal in Eastern Canada
1990 - IRG/WP 3587
Increasing public awareness, prompted by environmental groups such as Greenpeace, concerning the use and disposal of treated wood is becoming a serious issue in Canada. Producers and user groups of treated Pentachlorophenol (PCP) utility poles are at the forefront of public, government and media attention. If, as expected, further limitations on the use and disposal of PCP by the public are imposed, the producers and users of this material will have to find alternative means of the means of pole disposal.
S D Henry


World survey on the status of pollution control in the field of wood preservation
1976 - IRG/WP 369
In 1974 the IRG/WP-Secretariat distributed a "Questionnaire on the state of pollution control in the field of wood preservation" which was prepared by the author. The questionnaire consisted of two parts. Part A asked "General questions" on - the position of wood preservation in the respective country - the use of preservatives - the type of application of wood preservatives in different fields - the state of pollution control. Additional details to the questions of Part A were requested in Part B. This part also included questions on - the special work on pollution control in wood preservation in the respective country - the use of residues and old timber. A preliminary report on the answers to the questionnaire was given in IRG-Document 56 to the plenary meeting at Vienna, Austria in June 1974. Since then, all questionnaires, including also those received after the Vienna-meeting, were evaluated in detail. Mistakes made during the rough evaluation in 1974 have been corrected. Therefore certain differences may occur between the preliminary report and the present one. Further more the answers to Part A and Part B of the questionnaire have been combined in the tables of this report.
H Willeitner


Use of wood-decay fungi for disposal of PCP-treated wood
1995 - IRG/WP 95-50040-33
Although PCP has been classified as a priority pollutant, PCP-treated wood products are currently allowed to be disposed of as ordinary solid (non-hazardous) wastes in the US. Non-regulated disposal of these materials is allowed because PCP concentrations in extracts from PCP-treated products such as utility poles and crossarms, determined by the Toxicity Characteristic Leaching Procedure (TCLP) have been shown to be well below the regulatory level of 100 mg/L PCP. However, with increasing concerns regarding future liability associated with PCP-treated materials and with the reticence towards accepting large amounts of woody debris, the option of disposing by landfilling is rapidly disappearing. Also, disposal by incineration is expensive and not readily available. Therefore, alternate methods of disposal are needed. In laboratory experiments the white-rot fungus Trametes hirsuta has been shown to cause an 84% decrease in the PCP concentration of PCP-treated wood. After 4 weeks, the fate of 14C[PCP] in softwood chips inoculated with Trametes hirsuta was as follows: 27% was mineralized; 42.5% was non-extractable and bound to the chips; 23.5% was associated with fungal hyphae, and 6% was organic-extractable. Using biopile technology the use of Trametes hirsuta for the large-scale treatment of PCP-treated wood was evaluated on wood chips from southern pine and western red cedar utility poles that were treated with PCP. The effectiveness of the treatment was evaluated throughout the treatment period by assessing the PCP concentration in the chips and the toxicity of the chips using a submitochondrial particle assay. Fungal growth was assessed indirectly by measuring the ergosterol content of the chips throughout the treatment period.
R T Lamar


Recycling of treated timber by copper smelter
1994 - IRG/WP 94-50030
A preliminary trial was carried out to see whether copper smelting process is able to recycle CCA treated timber. As a result of the first trial almost a full recovery of both copper and arsenic was achieved. Recovered metals were utilized in manufacturing CCA preservatives. The energy bound in wood is utilized in the flash smelting process and the burning gases are fed to the sulphuric acid plant. On the contrary chromium undergoes a slag treatment process where it forms insoluble compounds and is then removed together with the final residue. A trial was carried out at the copper line of Outokumpu Harjavalta Metals. Outokumpu Oy is the major producer of copper in Finland and the company also produces CCA preservatives for the Nordic market.
A J Nurmi, L Lindroos


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


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