Your search resulted in 30 documents. Displaying 25 entries per page.
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
Electrodialytic remediation of CCA-treated wood in larger scale
2005 - IRG/WP 05-50224-20
A pilot plant for the electrodialytic remediation of CCA-treated waste wood has been developed and tested at the Technical University of Denmark. Results from two experiments with different amount of wood chips are presented here. Prior to the electrodialytic remediation the wood was soaked in oxalic acid and phosphoric acid. The main purpose of soaking is to remove the most available fraction first and then use the electric current to remove the less available fractions. This proved successfully as the majority of CCA could be removed by soaking. The highest overall removal was obtained in an experiment with 100 kg wood chips. The electrode distance was 60 cm and 87% Cu, 81% Cr and >95% As was removed. In an experiment with 250 kg wood and an electrode distance of 150 cm, the removal of Cu and Cr was significantly lower, both below 60%. This is presumed to be due to the limitations of the power supply used. In the same experiment 96% As was removed, indicating that As is the easiest removable of the three CCA components. This result is very encouraging since As is the component of most environmental concern.
I V Christensen, L M Ottosen, A J Pedersen
Electrodialytic remediation of a soil from a wood preservation industry polluted by CCA
1998 - IRG/WP 98-50101-14
Soil contamination is often found at wood preservation sites due to spills, dripping of excess preservatives and deposition of sludge associated with dissolved salts of copper, chromium and arsenic (CCA). The electrodialytic process is a promising heavy metal soil remediation technique. It is based on a combination of the electrokinetic movement of ions in soil with the principle of electrodialysis. The technique was tested in five experiments using a laboratory cell on a CCA contaminated Portuguese soil. The duration of the experiments varied (from 18 to 125 days) but the dc current density was kept constant (0.2 mA/cm2). The development of the contaminant concentration profiles in the soil after the experiments was investigated. pH and the speciation of contaminants were identified as key parameters of importance to the remediation process. It was found that it was possible to decontaminate the soil to an extent lower than the recommended critical values for copper concentration in soils.
A B Ribeiro, A Villumsen, G Bech-Nielsen, A Réfega, J Vieira e Silva
Wood preservation sites polluted by CCA. Is potassium diphosphate incubation a catalyst for the electrodialytic remediation of these soils?
1998 - IRG/WP 98-50106
As part of an evaluation of a newly developed electrodialytic soil remediation technique, we investigated the incubation of a contaminated soil (from a Portuguese wood preservation site polluted with CCA) with potassium diphosphate as a possible catalyst for the removal of heavy metals and metalloids. A chemical sequential extraction scheme (SE) applied to the soil has shown that the potassium diphosphate (0.1 M), used for the attack of forms organically bound, extracted 30% of Cu, 15% of Cr and 23% of As. Two electrodialytic laboratory experiments (E and O) were carried out for 35 days in a laboratory cell, with a current density of 0.2 mA/cm2. In Exp. E the contaminated soil was put in the cell as it was sampled, and in Exp. O, the soil was previously incubated with 0.1 M K4P2O7, for 51 h. The aim was to compare results of process efficiencies by maintaining either acid or basic pH conditions in the soil, both media known to keep solubilization of metals high. Results show that the remediation process was not more efficient in the soil submitted to the pre-treatment, for the considered time length, as total Cu, Cr and Zn soil concentrations were higher after Exp. O than after Exp. E. The K4P2O7 incubation did not succeed in maintaining a basic pH in the soil. However, the soil SE results show that Exp. O put more Cu, Cr and Zn in "soluble and exchangeable forms" than Exp. E. If the process had been run for a longer period, electromigration could have acted more efficiently and these elements are expected to be removed from the soil, increasing the overall efficiency of the process. Addition of extra alkali could have furthered the process.
A B Ribeiro, G Bech-Nielsen, A Villumsen, A Réfega, J Vieira e Silva
Effect of EDTA on removal of CCA from treated wood
2002 - IRG/WP 02-50182
Since substantial amounts of chromated copper arsenate (CCA) remain in the wood for many years, the disposal of CCA-treated wood causes escalating environmental concerns. Additionally, wood waste is generated when treated wood is put into service, for which environmentally benign disposal technologies need to be developed. Novel approaches to remove copper, chromium, and arsenic from CCA-treated waste wood are needed to overcome such environmental concerns. Acid extraction, one of the most extensively used methods, has been studied by several researchers for removal of copper, chromium, and arsenic from CCA-treated wood. In this study, EDTA (ethylenediaminetetraacetic acid) extraction of copper, chromium, and arsenic from CCA- treated wood was evaluated using batch-leaching experiments. EDTA is one of the most common chelator used to bind the metal ions in extremely stable complexes in heavy metal contaminated soils and thus to remediate such substrates. EDTA forms water soluble complexes with many metal ions and it is used to release for the various metals. In the study, chips and sawdust containing CCA were processed by EDTA extraction to remove the metal elements present in the form of oxides. CCA-treated wood samples were extracted with four different concentrations of EDTA (0.0, 0.01, 0.1, and 1.0%) for 4 and 24 hours at room temperature. Exposing CCA-treated chips and sawdust to EDTA extraction enhanced removal of CCA components compared to extraction by deionized water. Grinding CCA-treated wood chips into 40-mesh sawdust provided greater access to and release of CCA components. Extraction with 1% EDTA solution for 24 h released 60% copper, 13% chromium, and 25% arsenic from treated chips. EDTA extraction of treated sawdust samples resulted in 93% copper, 36% chromium, and 38% arsenic release. The pH of EDTA solutions ranged from 2.2 to 3.2, providing acid conditions, which facilitate release of copper element. The results suggest that EDTA extraction removes significant quantities of copper from CCA-treated wood. Thus, EDTA could be important in the remediation of wood waste treated with the newest formulations of organometallic copper compounds and other water-borne wood preservatives containing copper.
S N Kartal
Review of remediation methods of sites contaminated by wood preservatives - testing of filter material for use in permeable barrier technology
1999 - IRG/WP 99-50141
Several treatment methods are currently available for treatment of contaminated sites. Soil and water can be treated by immobilisation, separation or destruction of contaminants. It has been common to use intensive treatment methods starting with soil excavation to reach strict purification goals. However, technical and financial reasons make it difficult to reach the desired treatment criteria. As a result, alternative treatment methods are now being allowed. Less intensive in situ methods are being developed, such as natural attenuation, phytoremediation and permeable barriers. A permeable barrier is a passive treatment method for contaminated groundwater. A study was conducted to test various barrier materials for filtering creosote contaminated groundwater. Peat, compost, bark, sewage sludge and sewage sludge pellets were tested out for sorption of phenol, 2-methylphenol and 2,4-dimethylphenol. Peat and compost showed best sorption efficiency. Peat and compost were mixed with sand in various fractions to see if sand can be used to improve hydraulic properties of the filter material.
G Rasmussen, H Iversen, S Andersen
Remediation of pentachlorophenol- and creosote-contaminated soils using wood-degrading fungi
1994 - IRG/WP 94-50021
Microbiological treatment of hazardous wastes has generally been associated with the use of bacteria. During the past decade a significant body of evidence has accumulated that demonstrates that fungi, in particular white-rot fungi, have the ability to degrade a wide range of hazardous organic compounds (xenobiotics) and thus might also be useful for treatment of materials contaminated with these compounds. Our work has focused on the development of a soil remediation technology that is based on the xenobiotic-degrading abilities of these fungi. This work has demonstrated that the technology is useful for remediation of pentachlorophenol-contaminated soils and may also be useful for creosote-contaminated soils. In this presentation the fungi and their xenobiotic-degrading abilities will be described and a summary of applications of this technology to remediation of PCP and creosote-contaminated sites and a discussion of technological developments necessary for commercialization of the technology will be given.
R T Lamar, T K Kirk
Evaluation of fungal remediation of creosote treated wood
1998 - IRG/WP 98-50101-25
Biotechnological remediation of creosote treated wood may be of interest in connection with novel recycling processes. White rot fungi and/or their ligninolytic enzyme systems are supposed to be valuable tools for such processes. This paper reports about results achieved when creosoted wood was treated in solid substrate fermentation with selected white rot fungi after different extraction procedures. None of different optimized fermentation conditions enabled the colonization of creosoted wood. The minimal inhibitory concentration for fungi was found to be about one power of ten below the actual concentration in railway sleepers. The efficiency of various solvents to extract creosote below the MIC for fungi was investigated. When 16 PAHs were analysed by HPLC under growth conditions, the best fungal strain degraded 100% of the low molecular weight PAHs and 92% of the 4-5 ring PAHs after 16 days. The lowest reduction was found to be 79% for benzo(b)fluoranthene. The results are discussed with respect to the application of white rot fungi for technical processes in combination with novel recycling methods for creosote treated wood.
K Messner, S Böhmer
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
Economical analysis of the chemicals used on remediation copper, chromium and arsenic from out of service CCA-treated utility poles in Turkey
2004 - IRG/WP 04-50217
There are 20.7 million hectare forested area in Turkey. However, the wood products supplies do not meet demand. One of the wooden products is the utility poles. In Turkey, impregnation of utility poles has been started since 1960's and 5 million utility poles have been used until today since then. Although life time of the utility poles may vary depending on climatic conditions, average service time of utility poles used in Turkey is about 25 years. Therefore, it is estimated that each year 200.000 m3 utility poles are out-of-service and they need to be replaced. In recent years, because of the unwanted effects of out-of-service CCA treated utility poles either during their storage or being recycled, there is a urgent needs to find a way removing Copper, Chrome and Arsenic from out-of-service CCA treated utility poles. For this purpose, many scientists have been studying on remediation of CCA treated wood. In this study, oleic acid, chromotropic acid and citric acid were used to remove Cu, Cr and Ar from CCA treated wood samples. The objective of this study is to determine the chemical that provides the maximum Cu, Cr and Ar removal from CCA treated wood as well as the cost effective one.
E D Gezer, D Toksoy, Ü C Yildiz
Remediation of CCA-treated wood by chitin and chitosan
2005 - IRG/WP 05-50229
Chitin and chitosan are naturally abundant biopolymers which are interest of to research concerning the sorption of metal ions since the amine and hydroxyl groups on their chemical structures act as chelation sites for metal ions. This study evaluated the removal of copper, chromium, and arsenic elements from chromated copper arsenate (CCA)-treated wood via biosorption by chitin and chitosan. Exposing CCA-treated sawdust to various amounts of chitin and chitosan for 1, 5, and 10 days enhanced removal of CCA components compared to remediation by deionized water, only. Remediation process with 2.5 g chitin-containing solution for 10 days removed 74% copper, 62% chromium, and 63% arsenic from treated sawdust. Remediation of treated sawdust samples using same amount of chitosan resulted in 57% copper, 43% chromium, and 30% arsenic removal. The results suggest that chitin and chitosan are able to remove copper from CCA-treated wood. Thus, these most abundant natural amino polysaccharides could be important in the remediation of waste wood treated with the newest formulations of organometallic copper compounds and other water-borne wood preservatives containing copper.
S N Kartal, Y Imamura
Future Directions Regarding Research on the Environmental Impacts of Preservative-Treated Wood: Environmental Impacts of Preservative-Treated Wood. February 8-11, 2004, FL, USA
Workshop – Research Needs
2004 - IRG/WP 04-50222
This paper presents a series of documents that focus on research needs for potential future work focusing on the environmental impacts of preservative-treated wood. These documents were developed through a conference sponsored by the Florida Center for Environmental Solutions (FCES), located in Gainesville, Florida. The conference was held in Orlando, Florida, February 8 – 11, 2004 and the title of the conference was, “Environmental Impacts of Preservative-Treated Wood.” Approximately 150 people from 15 countries attended the conference. The “research needs” documents developed to date were summarized from: 1) feedback received from conference participants prior to the conference and 2) a two hour workshop held at the conclusion of the conference. A draft voting ballot has been prepared from these documents. This ballot is currently being reviewed by the FCES conference Technical Advisory Committee and a final ballot will be released in mid-April for a vote among the conference participants. A copy of the draft voting ballot is included at the end of this document. Results of the vote will be released at the 35th Annual IRG Meeting in Slovenia.
H M Solo-Gabriele, J D Schert, T G Townsend
Remediation of a large CCA-impregnation plant
1998 - IRG/WP 98-50101-13
During 1949-85 the Swedish Telecom ran a plant for pressure impregnation of poles in Hjältevad, 80 km east of Jönköping in the southern part of Sweden. About one million poles were treated with CCA-preservaties. Leaks and accidential spills have contaminated soil and groundwater within the 5 ha large site. The total amount of released arsenic, the main pollutant, is estimated to 6-7 metric tons. It has been considered necessary to reduce environmental and healthy risks. Different types of remedial measures have been evaluated, but finally a treatment concept based on soil washing was decided. The purpose of the remediation is to create the necessary conditions for sport activities and recreation in the area. The remediation was conducted in 1997. About 26 600 metric tons of soil with arsenic concentration exceeding 40 mg/kg was treated on site in a soil washing plant. Approximately 4.6 metric tons arsenic was removed from the site in a restfraction, but also in highly contaminated, not treated soil. This high concentrated soil material was placed in a safe hazardous waste landfill. The treated soil and the low contaminated soil (<40 mg/kg) was left on the site. The project, which is the first real soil washing remediation in Sweden, has been successful. The treatment goals are reached in all essentials. The time schedule and project budget are also managed.
Tolerance of Wood Decay Fungi to Commercial Copper Based Wood Preservatives
2002 - IRG/WP 02-30291
Due to the use of copper based preservatives like CCB or CCA for more than a century, copper tolerant fungi have appeared in some European countries in recent times. It is therefore important to find out whether this phenomenon is specific for only classical copper ingredients, or generally for all copper based formulation. Thus, we tested the tolerance of three commercial copper based preservatives and copper(II) sulphate as well as potassium dichromate for comparison. In this research, seven copper tolerant Antrodia isolates and copper intolerant fungus Gloeophyllum trabeum were tested using a screening test and standard laboratory test SIST EN 113. Screening test were performed on potato dextrose agar (PDA) with copper concentration between 5.0×10-4 and 2.5×10-2 mol/l. The tolerance determined by the screening test was not always comparable with results obtained with the standard laboratory test. However, results obtained on wood samples showed that various fungal isolates exhibited different levels of copper tolerance depending on the copper based biocide. Tolerant strains were able to decay copper sulfate as well as copper naphthenate preserved wood samples. On the other hand, even the most tolerant fungi could not decompose wood preserved with classical CCB or copper amine preservative. It can therefore be concluded that various fungal isolates exhibited different copper tolerance regarding copper formulations. This finding is very important for remediation of waste treated wood by fungi. For a successful detoxification of waste wood impregnated with multi salt preservatives like CCA or CCB the suitable tolerant fungal strains have to be used, simultaneously for synergistic action.
F Pohleven, M Humar, S A Amartey, J Benedik
The fate of salt preservatives in facility yard soils and decontamination of soils and drainage waters
1993 - IRG/WP 93-50001-25
Extensive studies during the past 10 to 15 years revealed that noticeable amounts of preservative components may be released in the environment by dripping off or by rain prior to fixation unless adequate precautions are taken. Therefore, soil and groundwater contamination especially from chromium-VI compounds but also from other inorganic and organic constituents exist in impregnation plants, possibly endangering the soil and groundwater ecosystem. The actual risk potential originating from chromium-containing wood preservatives in a practical situation are to be studied in the frame of a comprehensive research programme sponsored by the German Ministry of Research and Technology (BMFT). Accompanying laboratory investigations are performed with the aim of assessing the various types of water-soluble wood preservatives with respect to whether or possibly which compounds remain mobile und thus bio-available in the soil. Special attention is drawn to the question as to which effective constituents are adsorbed to soil particles depending on the mineralogical-geological composition of the soil, and at what situation the retention capacity for effective components of different soils would be exceeded. The results of the pilot study and of parallel running laboratory tests serve as a basis of deterioration analyses for grading and assessing the endangering potential in the ecosystem and shall provide a basis for the choice of adequate remedial concepts and measures to avoid such environmental impacts.
R-D Peek, H Klipp, K Brandt
Removal of copper, chromium and arsenic from CCA treated wood using boron compounds
2005 - IRG/WP 05-50230
This study evaluates the copper (Cu), chromium (Cr) and arsenic (As) removal from CCA treated wood using boron compounds such as boric acid, borax (sodium tetraborate), and Timbor (DOT, disodium octaborate tetrahydrate) at varying (3 and 5%) concentrations. Remediation processes were taken at 1, 5 and 10 day intervals. Metals in remediated chips or sawdust were then analyzed using ICP and XRF. Results showed that, higher level of Cu was removed followed by As and Cr. The percentage removal of metals was higher in saw dust then chips. Borax at lower concentration (3%) removed 41.4%, 18.3% and 44.9% of Cu, Cr and As, respectively, in 10 days while at higher concentration (5%) 65.8%, 55% and 55.8% of Cu, Cr, As, respectively, were removed for the same period. Boric acid removed 39.7%, 15.5% and 35.6% at lower and 50.7%, 48.9% and 50.9% of Cu, Cr, and As at higher concentration, respectively, while DOT was not an effective extractant. Distilled water extraction removed 27.3%, 23.7% and 22.8% of Cu, Cr and As respectively. In case of chips, borax removed 30.3%, 19.7% and 24.9% of Cu, Cr, and As; boric acid removed 25.5%, 12.2% and 19.5%; DOT removed 22.8%, 10.8%, 14.2% and distilled water 17.7%, 11.1% and 10.2% of Cu, Cr, and As, respectively. Increasing the concentration of solution has greater effect on elements removal. Among the three compounds tested, borax removed higher levels of metals compared to boric acid and DOT.
B Tarakanadha, T Hata, S N Kartal, W J Hwang, Y Imamura
Chemical Remediation of Beech Condensates
2004 - IRG/WP 04-50221
In the present work, The beech wood condensate are subsequently separated from the aqueous phase. Experimental results reveal the electrostatic interaction between the oppositely charged wood extracts after oxidation and Ca(OH)2. The influence of parameters such as pH, oxidation were studied. The increase in aqueous phase pH resulted in enhanced removal of wood extracts from water. The effect of pH is explained based on oxygen uptake. The organic compounds found in this type aqueous effluent are also responsible for brown color. The effectiveness of the treatment process in the abatement of such toxicity was monitored by following the total phenols concentration decay, COD and color reduction.
M Irmouli, J P Haluk
Remediation of a site contaminated with creosote and CCA - a case study
1998 - IRG/WP 98-50101-12
Over sixty years of wood preservation activity conducted by ImpregNor at Ilseng, Norway, has caused serious contamination of the soil. High concentrations of creosote have been found at two separate sites, one in connection to the creosote wood preservation plant, and one further downstream were residues from the creosote preservation have been deposited. High levels of chromium, copper and arsenic (CCA) are found in a third area around the CCA wood preservation plant and the related dripping/fixation area. A site investigation of the contamination situation revealed that both creosote and CCA were spreading out of the wood preservation plant area directly through the sewer and drainage systems and with the ground water. There was no acute danger for exposure to humans, but further spreading would increase the exposure risk. A remedial actions plan to prevent further spreading of contaminants was requested by the Norwegian Pollution Control Authorities in July 97. Three drainage trenches for the collection of groundwater have been constructed downstream from the contaminated areas. The trenches were excavated down to a confining low permeable clayey silt layer. HDPE membranes on the downstream wall of the trenches prevent contaminated water from migrating across the trenches. Free phase creosote and creosote contaminated water from the trenches are pumped through an oil separator constructed to remove creosote oil. The groundwater from the CCA contaminated area is collected and pumped through a sedimentation basin and reused in the preservation plant. Control of the effluent during the first six months will show if further water treatment is required. The use of in situ bioremediation to increase the remediation rate of the creosote contaminated areas will be further investigated to limit the duration of the "pump and treat" operation.
T Rødsand, K Hellum, H Lillemaehlum
Remediation of wood treatment sites in Finland
1999 - IRG/WP 99-50139
Finnish legislation in connection with soil contamination are firstly waste management legislation and secondly public health legislation and water legislation. There is no separate legislation concerning soil protection or remediation. The Ministry of the Environment has published a proposal for official contaminant guideline values to be used both as criteria for contamination and clean-up target values. Today whether a site is contaminated or not is evaluated according to provisional guideline values set by the Ministry in 1996. In the legislation the liability for remediation has been defined according to the "Polluter pays" principle. In case the polluter is not found or is not able to take care of the remediation, the municipality is responsible for the implementation of remediation, in some cases with the help of central government funding. In most of the cases remedial works have to have a licence from one of the 13 Regional Environment centers. The Ministry of the Environment set up a special nation wide project to evaluate the problems related to soil contamination. The project (SAMASE) published its report in the end of 1994. Report includes a list of potentially contaminated sites and as summary the number of suspected sites is presented. In 1994 the estimate of the number of sites to be remediated for the next 20 years was 1.177. Remediation activity of contaminated sites had long been fairly low, and in the early 901es the number of clean-up projects was 10 - 20. Remediation activity was stronly increased by the SAMASE-project and today the number of clean-up projects is about 150 annually.
Remediation of environmental impacts related to inorganic wood preservative chemicals using in-situ geochemical fixation
2001 - IRG/WP 01-50166-17
Use of the inorganic wood preservative chemical chromated copper arsenate (CCA) has resulted in several documented cases of soil and ground water contamination at wood treatment plants due to spills or releases of the treatment chemical. The most significant impact from releases of CCA to the environment is related to hexavalent chromium contamination of ground water. This is due to the relative solubility of the hexavalent form of chromium in ground water and its toxicity. The other metals associated with CCA, copper and arsenic, are generally less soluble and therefore not as mobile as hexavalent chromium under typical environmental conditions. Although hexavalent chromium is readily reduced to less soluble and less toxic trivalent chromium, and natural attenuation of hexavalent chromium in the environment has been documented (Palmer and Puls, 1994), often the volume of CCA released exceeds the natural reducing capacity of the soil. Under this scenario, a plume of ground water contamination by hexavalent chromium develops. This paper discusses various approaches to remediation (clean up) of hexavalent chromium associated with CCA releases to the environment, and focuses on an innovative in-situ (in-place) approach that saves significant time and money.
R M Thomasser, J V Rouse
A review of the efficacy and uses of deltamethrin for wood preservation
1996 - IRG/WP 96-30105
The synthetic pyrethroid deltamethrin, is one of the most active insecticides available for protecting and curing wood from attack by beetles and termites. Freshly felled trees can be protected against bark beetles by spraying to run off with a 0.025% Al solution (K-Otek EC25) with negligible leaching. Alternatively, sawn timber may be dipped in a 0.0125% Al solution for short to medium term protection. Trials data and European Norm (EN) test results have demonstrated that dipping, vacuum pressure impregnation (VPI) and deltamethrin as an LOSP treatment need to provide retention levels of as little as 10 g Al/m³ for the protection of timber for use in Hazard Classes I-III (above ground). When deltamethrin is included in glueline applications, then protection of plywood from attack by the subterranean termite, Coptotermes havilandii is provided by levels of <40 g Al/m³. EN test results, for protective (EN46) and remedial (EN22, EN48, EN118) uses, support surface application rates of <50 mg Al/m² and <20 mg Al/m², respectively, of ready to use (RTU) and water-dilutable products (K-Otek Anti-insect OL, K-Otek Anti-insect SL ). Surface application (brushing) of EC, OL and SL formulations resulted in approx. 90% of the applied deltamethrin being recovered from the outer 2 mm of wood blocks.
A J Adams, J L Lindars
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
Removing Cu, Cr and As from CCA treated yellow pine by oleic acid
2003 - IRG/WP 03-50202
In this study, CCA treated yellow pine utility poles were cut into three different dimensions and 4 different pH levels (2, 2.5, 3.5 and 5) of Oleic acid was used. The leached wood samples were collected at the end of the 1, 3, 7 and 14 days to determine the remaining Cu, Cr and As concentrations. The concentrations of Cu, Cr and As were determined by X-RF. The effects of pH, dimension and duration on remediation of CCA treated yellow pine wood samples were determined.
E D Gezer, Ü C Yildiz, S Yildiz, E Dizman, A Temiz
Thermochemical Remediation of Preservative-Treated Wood
2008 - IRG/WP 08-50254
Remediation methods continue to be developed and refined for CCA-treated wood in order to divert this material from landfills and create secondary products from the wood fiber. A two-step thermochemical remediation method was developed to assess the efficiency of metal removal from CCA-treated spruce flakes. Nearly all the metals (As, Cr, and Cu) were thermochemically extracted from chromated copper arsenate (CCA) treated Spruce using solutions of oxalic acid and sodium hydroxide. Oxalic acid was found to be highly effective for removing As and Cr, whereas mixtures of oxalic acid and sodium hydroxide were more effective for removing copper. Up to 100 % As and 97 % Cr were removed from treated flakes after one hour using a 1 % oxalic acid solution (pH 1.4) at 80 °C, but less half of the Cu was removed at pH 1.4 even after six hours. Nearly all the As, Cr, and Cu were extracted from the treated flakes after six hours using a 1 % oxalic acid solution adjusted to pH 3 with sodium hydroxide. However, the removal of As and Cr was slower with oxalic acid solutions that contained sodium hydroxide. A two-stage process in which the flakes were first extracted for one hour with oxalic acid (pH 1.4) then extracted for another hour after adjusting the solution to pH 3 with sodium hydroxide removed 99 % As, 96 % Cr, and 92 % Cu. The effects of temperature, pH, time, mixing, rinsing, and liquid to solid ratio on the removal of metals from CCA-treated Spruce flakes and particles is discussed.
R Sabo, C A Clausen, J E Winandy
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