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Analysis of contaminants in waste wood
2001 - IRG/WP 01-50179
Waste wood is increasingly used as fuel in Sweden. It is of Swedish origin as well as imported, Mainly from Germany and the Netherlands. The major chemical contaminants are surface treatments (paints etc) and wood preservatives. The surface treatments contribute in particular to contaminants of zinc and lead. In some cases zinc has been found to cause severe deposits in the furnaces. Surface treatments also contribute to increased levels of sodium, chlorine, sulphur and nitrogen. Preservative-treated wood is the most important source of increased levels of copper, chromium and arsenic in the waste wood. Waste wood imported from Germany contains less arsenic but the same amount of copper and chromium as Swedish waste wood. The fraction consisting of wood-based panels is comparably free from contaminants but as a result of the high contents of adhesives wood-based panels contribute to a higher proportion of nitrogen in waste wood than in forest residues. A great number of non-wood compounds (such as plastics and metals) do also contaminate waste wood. By careful and selective demolition and various sorting procedures most non-wood compounds will be separated from the waste wood. Metal objects of zinc, brass and aluminium are considered to be particularly troublesome as they may plug primary air openings. PVC residues may cause considerably higher levels of chlorine in waste wood. Chemical analyses indicate that the distribution in levels of impurities varies a lot between deliveries of waste wood. Difficulties to take representative samples probably contribute to this. The study has confirmed previous studies that waste wood contains a substantial proportion of fine fraction. 25-40% of the waste wood passed a sieve with a mesh size of 4 mm at screening trials. Chemical analyses indicated that the fine fraction will be the main contributor to contaminants of potassium, chlorine, sodium, zinc and lead.
J Jermer, A Ekvall, C Tullin
Étude de l'impact d'un xénobiotique sur le milieu aquatique: Approche méthodologique
1990 - IRG/WP 3586
L'action de xénobiotiques sur les communautés vivantes des écosystèmes lénitiques a été abordée à des échelles spatiotemporelles différentes. Dépassant le niveau des tests monospécifiques, nous avons effectué des essais en laboratoire sur des microcosmes contenant des végétaux ( Lemna minor ) et des bactéries et également sur des bassins de quelque m³ contenant une grande variété d'organismes. Les essais ont porté jusqu'à présent sur le Pentachlorophénol; ils seront poursuivis prochainement sur d'autres composés. Les résultats obtenus au laboratoire se sont avérés être transposables aux effets obtenus dans les bassins: le développement de souches bactériennes résistantes au PCP et l'inhibition de l'activité photosynthétique des différents groupes de végétaux constituent les principaux résultats de la contamination par le fongicide. Ces effets reposent sur les caractéristiques de dispersion et d'accumulation du produit étudiées par ailleurs. Il s'avère que l'approche méthodologique multidimensionnelle utilisé içi est très efficace et elle sera utilisée pour vérifier les effets d'autres xénobiotiques sur la structure et le fonctionnement des écosystème aquatiques.
G Blake, G Merlin
In-house accelerated method for testing decay resistance of treated wood
2004 - IRG/WP 04-20286
Fungicidal compounds often change their effectiveness when they are incorporated into candidate formulations. For this reason fungistatic effectiveness needs to be re-evaluated as many times as the formula has been modified for better performance. To avoid multiple expenses, in-house fungistatic tests are essential. Our goal was to develop in-house usable, simple but reliable and reproductive procedure for testing decay resistance of the Sansin priming formulae without a need for special testing equipment. Our preliminary trials have proved that commercially available, heat processed wood pellet fuel can be used as an excellent substrate for growing certain wood rotting fungi. In contact with water wood pellets quickly disintegrate and convert into sawdust, gaining up to three times increase in volume. When wood pellets are wetted with water containing hydrogen peroxide, the vapors of this antiseptic kill non-desirable air-borne contaminants and protect the substrate from further contamination for as long period as peroxide remains in the substrate at sufficient concentration. When peroxide protected substrate is spawned with well-organized fungal organisms (for example true decay/test fungi), they will rapidly colonize the substrate and develop a powerful mycelial network capable of decomposing most of the natural fiber based materials. Treated and non-treated wood specimens were buried in spawned, hydrogen peroxide protected wood pellet fuel-based substrate and placed in transparent, perforated plastic containers to determine the effect of this procedure on rapid colonization and accelerated wood degradation. Parallel test was set up with specimens inserted in 150mm diameter dishes containing fungal cultures developed on the beer based agar medium. The results after 45 and 90 days of exposure to the brown rot causing fungus Gloeophyllum trabeum indicate that the weight loss in control blocks in containers was higher than in the dishes for 7 and 11 percent respectively.
Contamination of recycled wood from selected recycling companies in Europe
2016 - IRG/WP 16-50322
Recycled wood is becoming more and more important material source for production of new materials and chemicals. For good quality of end products predominately clean recycled wood should be used. In present research, we have focus on concentrations of non-wooden materials in recycled wood and presence of inorganic pollutants: chlorine (Cl), chromium (Cr), copper (Cu), zinc (Zn), lead (Pb), iron (Fe) and bromine (Br). Sampling of different qualities of commercially available recycled wood was performed for one year in recycling companies from Germany, Slovenia, Finland and UK. Beside above mentioned long term monitoring, one for one batch fraction analysis was made as well. For nine different fractions soluble part and lignin content were determine also. Results showed that AI recycled wood (German classification), had low share of non-wooden materials and only few samples exceeds limit values for inorganic pollutants. On the other hand in AI-AIII mix recycled wood contains significantly higher portion of non-wooden material (up to 3 %). This mixtures had also higher concentrations of inorganic pollutants. More than 85% of samples, for at least one of the monitored chemicals, exceed limit concentration prescribed by German ordinance for recovered wood. Concentration of chemical elements in samples from nine different size fraction negatively correlates with particle size in the fractions. The same was observed also for soluble part and lignin content. In general we can conclude that recycled wood from big companies whit sophisticated sorting system contains less non-wooden material, and can provide rather clean AI wood. On the other hand AI-AIII mix recycled wood contained rather high concentrations of inorganic elements regardless the origin or sorting system.
B Lesar, M Humar, G Hora