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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
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
Evaluation of wood treated with copper-based preservatives for Cu loss during exposure to heat and copper-tolerant Bacillus licheniformis
1999 - IRG/WP 99-20155
Copper-based wood preservatives need to be effective against exposure to all types of microorganisms. Wood treated with six copper-based preservatives was exposed to 121°C and 20 psi pressure for 15 minutes under standard autoclave conditions and the copper-tolerant bacterium, Bacillus licheniformis CC01, for 10 d at 28°C and 150 rpm. Sixteen to 37 percent of the copper was released from the wood during autoclaving, with copper citrate demonstrating the highest percent loss. Forty-four to 82 percent of the copper remaining in the samples following autoclaving was removed during exposure to the bacterium in liquid culture; copper naphthenate in oil and ACQ-D had losses of eighty percent or greater of the remaining copper. The bacterium removed as much or more total copper in 4 of 6 gas-sterilized samples (85-94%) than the cumulative effects of steam-sterilization and the bacterium on treated samples. Copper loss from in-service treated wood compromises the efficacy of copper-based wood preservatives.
D M Crawford, C A Clausen
An introduction to environmental aspects of groundwater arsenic and CCA treated wood poles in Bangladesh
1997 - IRG/WP 97-50081
The environment comprises biosphere, lithosphere, atmosphere and hydrosphere. Therefore, environmental science is a multi-disciplinary study, includes life sciences, physical sciences, chemical sciences, geology, geography, meteorology, forestry, agriculture, soil science, hydrology, ecology, public health, engineering etc. Tremendous industrial and mining activities, deforestation and population explosion are threatening the very existence of life on earth.Groundwater is used for irrigation, drinking and other domestic purposes where other sources of water are not plenty. Groundwater contain different metals resulting from soluble minerals, deposited in ground during its origin. Thus concentration of metals in surface soils and water are increased day by day by lifting of groundwater. Surface soils and water also receive metals from industries and mines and as a result of multipurpose use of products from those. Deforestation is controlled by plantation and preservation of forest products by different wood preservatives. Recently groundwater in some underground rocks of Tertiary and Quarternary age in Bangladesh is very often known to contain arsenic (As) above permissible limits . On the other hand chromated copper arsenate (CCA) impregnated wooden poles has been used for rural electrification in Bangladesh since 1979. It is an attempt to find out through research and review of literatures that whether the groundwater As is contaminatable from As used in wood poles and whether the components of CCA cause environmental problems. Possible way of purification of arsenic containing groundwater for drinking have been suggested.
A K Lahiry
X-ray analysis of selected anatomical structures in copper/chrome/arsenic treated wood
1973 - IRG/WP 320
Application of analytical electron microscopy to problems in wood preservation has been very limited. Indeed, less than ten workers appear to have published their results using the technique, and of these' only two papers deal with energy dispersion procedures in the scanning electron microscope; the others employ the more familiar wavelength dispersive methods of the electron probe.
Copper based water-borne preservatives: The biological performance of wood treated with various formulations
1987 - IRG/WP 3451
Wood samples treated with the various components of CCA preservative singly and in combination were tested against a soft rot organism, a copper tolerant brown rot organism and in soil burial both unleached and after leaching. The results suggest that, of the elements tested, fixed copper is essential for preventing soft rot attack and fixed arsenic is essential for preventing attack by a copper tolerant brown rot organism in leaching environments.
S M Gray, D J Dickinson
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
The Effect of Soil pH on the pH of Treated Southern Pine in Ground Contact after 12 Months
2011 - IRG/WP 11-50281
Southern pine samples treated with soluble and particulate copper solutions were subjected to three soils that had been amended to provide acidic, neutral and alkaline conditions. Wood pH was measured prior to, and after 6 and 12 months after being placed in the soil to determine the effect of soil pH on wood pH.
L Jin, C Schauwecker, C Vidrine, P Walcheski, A Preston
The volatilization of arsenic on burning copper-chrome-arsenic (CCA) treated wood
1978 - IRG/WP 3111
Small scale burning experiments are described involving copper-chrome-arsenic treated wood. Approximately 20 per cent of the arsenic was volatilised when the wood was burned in air but 60 per cent when burned in an oxygen-enriched atmosphere, this increase is attributed to an increase in combustion temperature. Although a small increase in arsenic evolution was found with an increased concentration of CCA in the wood this increase is not considered sufficient to be of any practical importance. The concentration of water-soluble arsenic and chromium in the wood-ash was greater when the experiment was conducted with oxygen-enriched air.
A-J Dobbs, C Grant
A Preliminary Report on the Properties of Engineered Wood Composite Panels Treated with Copper Naphthenate
2005 - IRG/WP 05-40294
This paper reports on our preliminary investigation of the properties of randomly oriented strandboard which had waterborne or powdered copper naphthenate (CuN) incorporated into the board during manufacture. When compared to zinc borate-treated controls (ZnB), the mechanical properties of strandboard (MOR, MOE, work-to-maximum load, internal bond strength) were not adversely affected by treatment with either form of copper naphthenate. In general, values for mechanical properties followed the trend untreated controls > waterborne CuN = powdered CuN > ZnB. Water absorption and dimensional properties followed a similar trend. This preliminary study suggests that CuN is a viable alternative treatment for engineered wood composites.
J W Kirkpatrick, H M Barnes
Leachability And Decay Resistance of Copper-Treated Wood
2004 - IRG/WP 04-30337
Samples of scots pine sapwood (Pinus sylvestris L.) were treated with solutions of (Copper II sulfat-5 hydro + fluoroboric acid) and (Copper II sulfat-5 hydro + fluoroboric acid + boric acid) in order to determining to leachability and decay resistance against brown rot fungus (Postia placenta) and white rot fungus (Coriolus versicolor). Results indicated that the copper in treated wood is less strongly bound because of the higher copper concentration in the leachates from treated wood and leaching rate of Cu is highest initially and decrease over time. After leaching, however, weight losses increased because of the leaching of copper and boron compounds from wood, revealing a lower decay resistance.
A Temiz, T Nilsson, I Deemirtas, Ü C Yildiz
Leaching Characteristics of Copper in Copper Treated Wood
2003 - IRG/WP 03-30316
The leaching characteristics of copper in copper treated bamboo and other wood species such as slash pine and poplar has been conducted in this paper according to AWPA M11-87 standard, the result indicates that: --Copper fixation rate of salts from organic acids such as citrate and oxalate and malate is less than other non-organic acid formulations. --Copper fixation rate of oven-dried bamboo samples is less than air-dried bamboo samples for all formulations containing copper. --Copper fixation rate of bamboo treated with ACQ containing dimethyl didecyl ammonium chloride (DDAC) is higher than other type of ACQ formulation containing benzalkonium chloride. Copper fixation rate of ammonia-based ACQ-B treated bamboo is higher than amine-based ACQ-D while in the same retention level. --Copper fixation rate in some formulations containing phosphate is higher than non-phosphate ones.
Mingliang Jiang, Junliang Liu, Daochun Qin, Yamei Wang, Zehui Jiang
Leaching and fixation characteristics of chrome-copper-fluoride-zinc (CCFZ) treated wood
1996 - IRG/WP 96-30096
The leaching characteristics of radiata pine sapwood blocks treated with CCFZ were evaluated by the AWPA standard leaching test. The rate of fixation of the preservative components in CCFZ treated radiata pine were also evaluated by quantitative analysis of solution expressed from the treated wood. Both leaching and fixation characteristics of CCFZ were compared with CCA-Type C treated wood samples. The permanence of CCFZ is excellent and comparable to that of CCA-Type C, and the rates of CCFZ fixation were similar to those found for CCA-Type C. These results suggest that CCFZ has a potential as alternative preservative for the replacement of CCA-Type C.
Gyu-Hyeok Kim, Jong-Bum Ra
Kiln drying of CCA-treated wood - Some safety and environmental considerations
1987 - IRG/WP 3443
Vapours and condensate from a condenser kiln in which CCA-treated wood was being dried have been collected and analysed. The concentrations of arsenic, copper and chromium found in the vapours from the drying process were well below Swedish threshold limit values. The contents of arsenic and chromium were also low in the condensate, although the copper content was fairly high. The latter result was probably because the low pH of the condensate caused some copper to be leached out from the copper pipes of the dehumidifier device. If precautionary measures are taken when condenser type kilns are constructed in order to prevent the leaching of heavy metals by low pH condensate liquors, there would seem to be no safety or environmental problems with this type of kiln.
J Jermer, B Lundberg
Applications of the shower test. Part B: Results from CC and CCB treated wood: influence of fixation process
1993 - IRG/WP 93-50010
This report outlines the results of shower tests conducted on CC and CCB treated wood. The results indicate the fairly good fixation of chromium and the reasonable fixation of copper in CC and CCB formulations, as judged by the leaching limits within the Environmental Regulations. In general boron leaches to a higher extent than chromium and copper. The shower test has proven to be a useful quality control and research test. It determines reasonably accurately the leaching under simulated conditions and, admittedly from a limited number of tests, it can determine differences between various fixation cycles. Natural fixation, controlled climate room fixation and steam fixation were compared. Overall the sleam fixation process gave the lowest leaching figures although the selection of an appropriate fixation facility is a question for individual companies, taking into account capital, customer base, throughput etc.
W J Homan, H Militz
Experiences with penetration of copper-based wood preservatives
2001 - IRG/WP 01-20233
In the Nordic countries there is a long tradition of result type based specifications for preservative-treated wood. A common Nordic standard for treated pine (Pinus sylvestris) wood was published in 1976. After a revision in 1989 this standard, then named INSTA 140, defined four classes of treated wood: M, A, AB and B. Treaters producing according to this standard had to be affiliated to a quality control and certification scheme. When the European standards EN 351 and EN 599 were to be implemented, the Nordic Wood Preservation Council issued a Nordic application document where the traditional wood preservation classes were defined in terms of EN 351 and EN 599. The present paper describes briefly how the European standards have been implemented in the Nordic countries. During the last years the use of CCA-preservatives has been restricted in the Nordic countries. New copper-based, chromium and arsenic free preservatives have been introduced for commodities above ground. This has by no means been without complications. The treaters have had severe problems to comply with the treatment requirements. Pilot plant treatment trials confirm that the penetrating properties of the chromium/arsenic free preservatives differ substantially from CCA. Experience from the Nordic quality control and certification scheme shows that it is often difficult to judge the penetration of the chromium and arsenic free preservatives. Different copper reagents give different results. A comparative test showed that ammoniumhydroxide and rubeanic acid as reagent for copper was the most sensitive to copper and performed better than other reagents tested.
J Jermer, F G Evans, I Johansson
Susceptibility of CCB treated wood to fungal colonization
2003 - IRG/WP 03-10492
CCB treated wood is generally resistant to all wood decay fungi. However, like CCA impregnated wood, susceptibility of CCB treated wood to copper tolerant fungi have been observed. The ability of various brown rot fungal hyphae to penetrate and overgrow the wood samples was investigated. Samples made of Norway spruce (Picea abies) were impregnated with 5 % CCB solution according to the EN 113 procedure. After conditioning, part of the samples was leached according to the EN 84 method. Small stick of unimpregnated wood (r = 1.5 mm, l = 25 mm) was inserted into a hole, bored in the center of the samples, and after that sealed with epoxy coating. Sterilized, leached and non-leached impregnated and unimpregnated specimens were exposed to two copper-tolerant (Antrodia vaillantii, Leucogyrophana pinastri) and two copper sensitive (Poria monticola, Gloeophyllum trabeum) brown rot fungi for one, two or four weeks. After exposure, the inserted wood pieces were removed from the specimens and put onto nutrient medium in petri dishes. Growth of the hyphae from those wood pieces was then visually determined. Rate of colonization by the fungi were determined by measurement of CO2 production. After that, mass losses of parallel specimens were also determined. The fastest colonization of the unimpregnated specimens was by G. trabeum (one week). On the other hand, no fungal growth could be detected on non-leached CCB impregnated specimens even after four weeks of exposure. However, significantly more intense colonization by the copper tolerant fungi were detected on the leached CCB treated samples.
F Pohleven, U Andoljsek, P Karabegovic, C Tavzes, S A Amartey, M Humar
Report on the burning of wood treated with wood preservatives containing copper, chromium and arsenic
1976 - IRG/WP 379
Mixtures of copper, chromium and arsenic salts are used extensively in the UK to preserve timber. This report is concerned with the fate of these metals when timber treated with these salts is burned. A large percentage of the arsenic present in the timber is shown to be volatilised during combustion and the potential environmental implications of this are assessed by comparison with the release of arsenic during coal burning. From this assessment it is concluded that burning of treated wood is unlikely to add significantly to the quantity of arsenic present in the atmosphere, although the concentration of arsenic in the discharged flue gases could give rise to local problems. Much of the arsenic and the chromium that remains in the ash is in the water soluble form and the possible implications of this are discussed. Recommendations based on findings reported here have been made to the Directorate General Water Engineering for consideration by the Arsenic Wastes Working Party which will be producing guidelines for the disposal of treated wood under the Control of Pollution Act 1974.
A J Dobbs, C Grant
Evaluation of the corrosivity of the treated wood - Laboratory vs field test methodologies
2000 - IRG/WP 00-20211
The corrosivity of treated wood to fasteners has been evaluated using laboratory test procedures, including AWPA Standard E12-94. The standard method was modified in order to allow detailed study of commercial metal fasteners in terms of sample types, installation configuration and exposure conditions. Parallel field tests were also performed. The experimental results generated from these tests suggest that the laboratory test methods accelerate metal corrosion relative to the field performance conditions for only certain preservative treatments. The influence of performance properties of water repellent treated wood on the corrosivity testing methods is also discussed.
L Jin, A F Preston
Copper leaching from Kemwood ACQ and Embalit CBC treated wood products
2000 - IRG/WP 00-50150
TNO has performed a study on the leaching of copper from Kemwood ACQ and Embalit CBC treated wood products, further referred to as ACQ and CBC. The sawn dry wood has been impregnated using an industrial vacuum-pressure process with ACQ (with or without Ultrawood 4) or with CBC, under supervision of Flexchemie B.V. After treatment samples have been transported and subjected to leaching tests at TNO. The leaching tests applied were a submersion test according to NEN 7345 and shower tests according to a fixed protocol (Havermans et al., 1993). Parallel to each shower tests two or three screening tests for leaching have been performed, according to the existing guideline (BRL 0601, 1999) and according to experimental spray and submersion protocols. The screening should indicate, if the leaching limits of the guideline are likely to be met or not. The results of the screening leaching test have been plotted against the results of the shower tests. It has shown that the existing leaching limit for the "standard" guideline screening test of 0.5 mg copper per ml. is too low and does not indicate if the wood will perform well in the shower test, for both ACQ and CBC treated wood. The experimental spray test has shown to be fairly good as prediction for compliance in the shower test. Furthermore the submersion test according to NEN 7345 has shown promising reductions with a factor 3,7 of copper leaching in ACQ and Ultrawood 4 treated Norway spruce compared to an earlier test with ACQ treated Scots pine. The copper emission in CBC treated Scots pine was a factor 2,5 higher compared to the ACQ-Ultrawood 4 treated Norway spruce.
P Esser, W L D Suitela, H Trompetter
The influence of copper (II) chemicals on the weathering of treated wood. Part 1: ACQ treatment of wood on its weathering
1994 - IRG/WP 94-30040
Wood weathering can be accelerated by alkylammonium compound (AAC) treatment, and slowed by ammoniacal copper quat (ACQ) treatment. This study aims at investigating the influence of ACQ treatment of wood, especially the present of copper (II), on its weathering. ACQ, CCA and DDAC treated microtomed sections of southern yellow pine earlywood were prepared and naturally weathered for five periods, totally 35 days. The compositional changes in the weathered samples with preservatives, retention and exposure time were examined using FTIR spectroscopy. The FTIR spectra showed that ACQ treatment slowed wood photodegradation mainly via inhibiting the formation of carbonyls and delignification during weathering. 2% ACQ treatment provided effective protection against wood photo-oxidation.
Ruiying Liu, J N R Ruddick, L Jin
Fungal remediation of CCA-treated wood
2004 - IRG/WP 04-50210
This study evaluates oxalic acid accumulation and bioremediation chromated copper arsenate (CCA) treated wood by three brown-rot fungi, Fomitopsis palustris, Coniophora puteana, and Laetiporus sulphureus and ten mold and staining fungi, Aspergillus niger, Aureobasidium pullulans, Gliocladium virens, Penicillium funiculosum, Rhizopus javanicus, Ceratocystis pilifera, C. peceae, Alternaria alternata, Trichoderma viride, and Cladosporium herbarum. In the study, the fungi were first cultivated in a fermentation broth in order to accumulate oxalic acid and bioremediation of CCA-treated wood was then performed through leaching of heavy metals inside the broth. F. palustris and L. sulphureus exposed to CCA-treated sawdust for 10 days caused a decrease in As of 100% and 85%, respectively however C. puteana remediation removed 18% As from CCA-treated sawdust. Likewise, Cr removal in F. palustris and L. sulphureus remediation processes was higher than those in C. puteana depending on less oxalic acid accumulation compared to F. palustris and L. sulphureus. All mold and staining fungi caused more than 70% Cu removal however Cr removal rates varied from 20% to 50%. Arsenic removal showed variations among the mold and staining fungi from 30% to 90%. These results suggest that fungal remediation processes can remove inorganic metal compounds via organic acid production increasing the acidity of the substrate and increasing the solubility of the metals.
S N Kartal, Y Imamura
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
Soft-rot control in hardwoods treated with chromated copper arsenate preservatives. Part 3: Influence of wood substrate and copper loadings
1977 - IRG/WP 2100
The hypothesis is proposed that hardwoods need more chromated copper arsenate (CCA) than softwoods to protect them from soft-rot attack mainly because hardwoods are more readily consumed by soft-rot fungi. Simple model systems, using copper-supplemented agar or groundwood pulp treated with CCA showed that fungi tolerated more toxicant (copper) as more available substrate (malt) was provided. Soft-rot tests with CCA-treated hardwood blocks provided typical dosage-response curves when results were expressed as a ratio of substrate to toxicant (wood to copper). Furthermore, hardwoods needed 10 to 20 times more copper as CCA than softwoods to prevent soft-rot attack. When CCA was substituted by ammoniacal copper arsenate in 5 hardwoods, similar threshold values for soft-rot attack were obtained in terms of a wood-to-copper ratio. Hence, CCA may be behaving poorly against soft-rot fungi in our hardwood specimens mainly because the substrate contained too little copper. The practical implications of these results are discussed.
M A Hulme, J A Butcher
Copper storage in the digestive caecae of Limnoria tripunctata and Limnoria quadripunctata (Crustacea: Isopoda) tunnelling in CCA treated and untreated wood in laboratory cultures
1998 - IRG/WP 98-10257
Digestive tract tissues of Limnoria quadripunctata Holthuis and Limnoria tripunctata Menzies, tunnelling untreated and CCA treated Scot's pine sapwood under laboratory conditions were examined using X-ray microanalysis and transmission electron microscopy. Populations of both Limnoria species tunnelling treated and untreated wood stored copper within their digestive caecae in the form of spherical and irregular granules. The number of storage granules was found to be higher in those organisms tunnelling CCA treated wood. This study also demonstrated copper was stored in gut tissues at certain stages of Limnoria's moult cycle, although the highest levels were always observed in organisms tunnelling CCA. Chromium and arsenic were not stored in the midgut cells. The current study demonstrates a possible mechanism by which Limnoria may colonise CCA treated wood in service.
C Wykes, A J Pitman, S M Cragg