Recycling Of Wood Waste Research Articles

Avoided impact quantification from recycling of wood waste in Singapore: an assessment of pallet made from technical wood versus virgin softwood

Recycling of wood waste is beneficial in delaying and avoiding carbon emissions stored in trees. To justify the benefits of avoiding the carbon emissions, this paper has assessed, quantified and compared the carbon emissions of recycled wood waste (technical wood) with virgin softwood in the application of wooden pallet. Through the use of avoided impact in a comparative carbon footprint study, results show that technical wood pallet has lower carbon emission of 3.547 kg-CO2eq than virgin softwood pallet (4.009 kg-CO2eq), after taking into consideration of avoided impact. This assessment also identifies the “hotspots” for future carbon emission improvement. Transportation accounts for 67.64% of the carbon emission for virgin softwood timber while resin usage is the dominant factor (52.86%) for technical wood timber. In addition, scenario and sensitivity analyses are conducted which show that technical wood pallet has a larger reduction in carbon emissions than virgin softwood pallet, if the pallet lifetime is increased.

Study on the Recycling of Waste Old Ship-Wood

By introducing the supply and demand of China's wood resources, it summed up the necessity and problems of the recycling of waste wood. Then it presented that studying on the recycling of waste old ship-wood could provide new ideas for the recycling of waste wood. And then it in detail discussed that using which ways and means to achieve the efficient and high value-added recycling of waste old ship-wood on the premise of low-cost, green and environmental protection, and energy conservation and emissions reduction. And finally it pointed out that designers play key roles in the process of recycling waste wood and the recycling of waste wood has an expansive industrialization foreground which can boost the construction of “two-oriented society”.

Novel composite materials based on cavitated wood

A topical trend in the industrial and ecological development of Russia is elaboration of the methods for integrated use of all components of natural raw materials, in particular, woodbased biomass. Note that the integrated processing of the woodbased bio� mass is possible only in close cooperation of various woodbased industries. These include production of traditional materials, energy sources, chemical prod� ucts, and biologically active compounds approaching the geochemically and energetically closed cycle tech� nology. Currently, all woodbased industries related to either mechanical or chemical processing of wood produce specific wastes although in different amounts. The difficulty of targeted standardized processing of these wastes is related to the necessity of strict indus� trial classification of the wastes and their averaging taking into account the physicochemical properties of the substances that form the material and parts of the trees. It is important that bulky wastes of woodbased biomass are formed upon extraction from wood of bio� logically active compounds such as terpenes, polypre� nols, and flavonoids, which are usually present in small amounts in the initial raw material (1). For example, the larch wood remainders after the removal of arabinogalactan and dihydroquercetin are large� scale wastes, their weight being about 85% of the wood weight (2, 3). A promising method for waste wood recycling is the production of plate materials without or with mini� mized use of synthetic binders. This trend is promising as regards the environmental safety of constructional materials. It was proposed to manufacture plate mate� rials from the compression molding material resulting from the extensive physicomechanical modification of wood by explosive autohydrolysis occurring at elevated

Extraction of Heavy Metals from CCA Preservative-Treated Wood Waste Using Lactic Acid Bacteria: An Environment-Friendly Technology

The recycling of wood waste is a possible solution to the global environmental concerns associated with waste. It also has economic benefits and potential environmental benefits given the global warming potential of architectural waste. The recycling method for wood waste treated with Chromated Copper Arsenate (CCA) has been a subject of concern of the architectural use of wood. The disposal of CCA-treated wood has become a serious issue in many countries, due to increasing levels of contamination from chromium, copper and arsenic. Thus, the need to promote the recycling of the CCA treated wood waste after appropriate pre-treatment has been clearly described in the Construction Materials Recycling Act from the Japanese Ministry of Land, Infrastructure and Transport.

Recycling of wood for particle board production: accounting of greenhouse gases and global warming contributions

The greenhouse gas (GHG) emissions related to the recycling of wood waste have been assessed with the purpose to provide useful data that can be used in accounting of greenhouse gas emissions. Here we present data related to the activities in a material recovery facility (MRF) where wood waste is shredded and foreign objects are removed in order to produce wood chips for use in the production of particleboard. The data are presented in accordance with the UOD (upstream, operational, downstream) framework presented in Gentil et al. (Waste Management & Research, 27, 2009). The GHG accounting shows that the emissions related to upstream activities (5 to 41 kg CO(2)-equivalents tonne( -1) wood waste) and to activities at the MRF (approximately 5 kg CO(2)-equivalents tonne(-1) wood waste) are negligible compared to the downstream processing (-560 to -120 kg CO(2)equivalents tonne(-1) wood waste). The magnitude of the savings in GHG emissions downstream are mainly related to savings in energy consumption for drying of fresh wood for particleboard production. However, the GHG account highly depends on the choices made in the modelling of the downstream system. The inclusion of saved electricity from avoided chipping of virgin wood does not change the results radically (-665 to -125 kg CO(2)-equivalents tonne(- 1) wood waste). However, if in addition it is assumed that the GHG emissions from combustion of wood has no global warming potential (GWP) and that the energy produced from excess wood due to recycling substitutes energy from fossil fuels, here assumed to be coal, potentially large downstream GHG emissions savings can be achieved by recycling of waste wood (-1.9 to -1.3 tonnes CO(2)-equivalents tonne(- 1) wood waste). As the data ranges are broad, it is necessary to carefully evaluate the feasibility of the data in the specific system which the GHG accounting is to be applied to.

Recycling of wood waste as sustainable industrial resources—Design of energy saving wood-based board for floor heating systems

Recycled wood has two important functions for sustainable development, as an industrial resource and as a means of longer storage of fixed carbon from carbon dioxide by photosynthesis. Recycled wood-based board, such as medium density fiberboard (MDF), is treated to produce a base material of floor heating system. The concept of functionally graded material (FGM) is introduced for the design of energy saving wood-based board. The heat transfer phenomenon of an FGM base plate used in a floor heating system is modeled and analyzed. The basic equation of the unsteady two-dimensional heat transfer problem and the analytical method for an FGM plate with wood material properties are proposed. The analytical method consists of the Laplace transformation and the perturbation method for arbitrary grading patterns. The results of the numerical calculation suggest that the optimum FGM wood-based board can save more energy than the homogeneous material.

Effects of Wood Particle Size and Mixing Ratios of HDPE on the Properties of the Composites

The main goal of this research is to innovate wood-plastic composites by using various wood particle sizes and different mixture ratios (weight ratio) of HDPE (High Density Polyethylene). After mixing the wood particles (recycled wood waste) and the plastic powder, we use a molding and pressing process to make composites with a thickness of 12 mm. By doing so, the wood particle content can be increased to 75%. This kind of composite provides excellent dimensional stability, its moisture content is under 2.5%, and the thickness swelling rate after 24 hr water absorption is under 7.5%. The maximum static bending strength of this composite reaches 20.7 N/mm2, and is better than that of general commercial particleboards. The composite made of larger sized wood particles has better strength properties. In addition, when the plastic content ratio increases, the dimensional stability of the composite will increase as well. After the soaking process in boiling water, the static bending strength of wet composite remained at 50%; this shows the good weather resistance of the composite. The surface veneer overlaid peeling strength of the composite showed 1.02–1.63 N/mm. After the evaluation of processing, cost of material and strength properties of the composite, we would suggest that the use of 70% of wood particles and 30% of plastic powder is practical to produce proper sized composites.

Characteristics of particleboard made from recycled wood-waste chips impregnated with phenol formaldehyde resin

The main purpose of this study was to manufacture water-resistant particleboard for use in kitchens and bathrooms, and as flooring-based material and in outdoor environments. The chips were from recycled wood wastes of different wood species. The chips were divided into coarse chips with dimensions of 5–8 mesh and fine chips of 8–20 mesh, then, these chips were immersed in water-soluble phenol formaldehyde (PF) resin solution at concentrations of 4.5%, 6.5% and 10%. After 5 min, they were removed from the PF solution and dried in an oven until in a half-hardened condition. Three-layer mats with target densities of 0.70 and 0.80 g/cm 3 were formed by using fine chips for the face layer (25%) and back layer (25%) and coarse chips for the core layer (50%). A conventional hot press was used for fabrication of the particleboard, and the temperature, pressure and pressing time were 453 K, 2.9 MPa, and 5 min, respectively. The nominal dimensions of particleboard were 500×500×12 mm (thick). Result showed that the PF resin absorption content of chips (RC) increased linearly with an increase in the concentration of PF solution. Their relationship could be represented by the linear regression formula. The bending strength, internal bonding strength, and thickness swelling (%) of the PF-impregnated particleboards exhibited excellent performances compared to those made in the past, and the retention rate (%) of the modulus of rupture (MOR) and modulus of elasticity (MOE) of PF-impregnated particleboard after treatment in hot water (343 K) for 2 h were maintained at 48.7–84.5% and 49.2–82.7%, respectively. Characteristics of the ultrasonic velocity in the mechanical direction were similar to those in the vertical direction. In addition, there were significant relationships between the ultrasonic velocity and the mechanical properties of the particleboard, and this meant that we could evaluate the properties of the particleboard using ultrasonic velocity.

Life cycle assessment of wood wastes: A case study of ephemeral architecture

One of the most commonly used elements in ephemeral architecture is a particleboard panel. These types of wood products are produced from wood wastes and they are used in temporary constructions such as trade fairs. Once the event is over, they are usually disposed into landfills. This paper intends to assess the environmental effects related to the use of these wood wastes in the end-of-life stage. The Life Cycle Assessment (LCA) of two scenarios was performed, considering the recycling of wood waste for particleboard manufacture and energy generation from non-renewable resources (Scenario 1) versus the production of energy from the combustion of wood waste and particleboard manufacture with conventional wooden resources (Scenario 2). A sensitive analysis was carried out taking into account the influence of the percentage of recycled material and the emissions data from wood combustion. According to Ecoindicator 99 methodology, Damage to Human Health and Ecosystem Quality are more significant in Scenario 2 whereas Scenario 1 presents the largest contribution to Damage to Resources. Between the two proposed alternatives, the recycling of wood waste for particleboard manufacture seems to be more favorable under an environmental perspective.

Evaluation of the environmental impact of waste wood co-utilisation for energy production

The need for a practical, economic and environmentally sound solution for waste wood arises from the requirements for resource conservation and recent regulations. Co-firing with coal is a promising option for the thermal recycling of waste wood. The overall environmental impact caused by the co-utilisation of waste wood with coal was evaluated by using life cycle assessment as established by Society of Environmental Toxicology and Chemistry (SETAC) [A technical framework for life cycle assessment. Washington, DC: SETAC, USA; 1991, Guidelines for life cycle assessments: A code of practice. Brussels: SETAC, Europe; 1993]. This provides opportunities to evaluate direct environmental impact, to identify possible improvements, and to reduce energy resource consumption. In this work, the environmental impact of co-utilising lignite and waste wood in an industrial steam boiler was evaluated. Results obtained showed that co-utilisation is technically feasible and can meet strict environmental standards. A net decrease of CO 2 emissions can be achieved by the thermal use of waste wood, as well as conservation of fossil fuel resources, minimisation of waste disposal and reduction of impacts on health.

Waste wood recycling as animal bedding and development of bio-monitoring tool using the CALUX assay

Animal bedding made of waste wood samples from seven different plants in Japan were chemically analyzed in terms of persistent organic pollutants (POPs) including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs), coplanar polychlorinated biphenyls (Co-PCBs), drin compounds, chlordane compounds and various inorganic toxic compounds (Cr, Cu, As, B, Cd and Pb) to investigate the chemical characteristics and levels of contamination. Further investigation was conducted to determine the success of applying the Chemically Activated Luciferase Expression (CALUX) bioassay to the waste wood samples in combination with a cleanup procedure for the detection of dioxin-like compounds in order to develop the CALUX bioassay as a rapid and cost-effective screening/monitoring method and a contributive tool to risk management in the waste wood recycling process. For the cleanup procedure, crude extracts from wood samples were prepared by dimethylsulfoxide (DMSO)/n-hexane extraction, and then the extracts were processed by silica gel–44% sulfuric acid reflux treatment at 70 °C for 60 min to yield the bioassay fractions.The presence of POPs and inorganic toxic compounds were confirmed in most of the litter samples. In particular, Co-PCBs in one sample (litter dust) showed a high concentration level (1,200,000 pg/g, 240 pg TEQ/g), suggesting the potential for contamination from demolition waste.The CALUX assay-determined TEQs (CALUX-TEQs) were significantly high in the sample after DMSO/n-hexane extraction, probably due to labile aryl hydrocarbon receptor (AhR) ligands such as PAHs; however, they were remarkably reduced through a single silica gel–44% sulfuric acid reflux treatment. The ratio between CALUX-TEQ values and WHO toxicity equivalent values (WHO-TEQ) obtained by congener-specific chemical analysis ranged from 0.058 to 22 and show comparatively good agreement. Underestimation in some samples, however, was observed where WHO-TEQ values of Co-PCBs contributed greatly to total WHO-TEQ values. Reasons for this gap could be lower CALUX assay-determined relative potencies (REPs) than the WHO-TEFs for these congeners or AhR-antagonistic effects of non dioxin-like PCBs which coexist at higher concentration than Co-PCBs. The CALUX assay is proposed as a promising application in the recycling process of wooden materials.

Allocation in lca of wood-based products experiences of cost action E9 part i. methodology

The treatment of allocation in the descriptive LCA of wood-based products has been discussed for a long time and different solutions have been presented. In general, it is accepted that the influence of different allocation procedures on the results of LCA of wood-based products can be very significant. This paper is a result of the Cost Action E9 ’Life cycle assessment of forestry and forest products’ and represents the experience of involved Cost E9 delegates. Wood is a renewable material that can be used for wood products and energy production. Consistent methodological procedures are needed in order to correctly address the twofold nature of wood as a material and fuel, the multi-functional wood processing generating large quantities of co-products, and reuse or recycling of paper and wood. Ten different processes in LCAs of wood-based products are identified, where allocation questions can occur: forestry, sawmill, wood industry, pulp and paper industry, particle board industry, recycling of paper, recycling of wood-based boards, recycling of waste wood, combined heat and power production, landfill. Following ISO 14 041 a step-wise procedure for system boundary setting and allocation are outlined. As a first priority allocation should be avoided by system expansion, thus adding additional functions to the functional unit. Alternatively, the avoided-burden approach can be followed by subtracting substituted functions of wood that are additionally provided. If allocation cannot be avoided, some allocations methods from case studies are described. The following conclusions for allocation in LCA of wood-based products are given. 1) Avoid allocation by expansion of system boundaries by combining material and energy aspects of wood, meaning a combination of LCA of wood products and of energy from wood with a functional unit for products and energy. 2) Substitute energy from wood with conventional energy in the LCA of wood products to get the func-tional unit of the wood product only, but identify the criteria for the substituted energy. 3) Substitution of wooden products with non-wooden products in LCA of bioenergy is not advis able, because the substitution criteria can be too complex. 4) If avoiding allocation is not possible, the reasons should be documented. 5) Different allocation procedures must be analysed and documented. In many cases, it seems necessary to make a sensitivity analysis of different allocation options for different environmental effects. It can also be useful to get the acceptance of the chosen allocation procedure by external experts. 6) Different allocation factors, e.g. mass or economic value, are allowed within the same LCA. 7) For allocation of forestry processes it is necessary to describe the main function of the forest where the raw material is taken out. In some cases different types or functions of forests must be considered and described. 8) Regarding the experiences from the examples, the following most practical allocation for some specific processes are identified: forestry: mass or volume; sawmill: mass or volume and proceeds; wood industry: mass and proceeds.

Present State of Wood Waste Recycling and a New Process for Converting Wood Waste into Reusable Wood Materials

The amounts of new wood used for housing construction and wood waste from demolished buildings was calculated using various scenarios of wood recycling. Diverse utilization of waste and increase in reuse rate was found to be effective to reduce the total amounts of final waste and the use of new wood materials. For recycling wood waste, the water vapor explosion (WVE) process was developed. In this process, wood materials were exploded from within by the force of water vapor generated by compression under high pressure and temperature and evaporation of the internal moisture, and they were separated into small wood elements. The WVE process was directly applied to the separation of Sugi (Cryptomeria Japonica) and Karamatsu (Laryx leptolepis) sawn timbers and slabs. The WVE of them produced small wood elements including fiber bundles, strands, and chips at certain experimental conditions (pressure, temperature, and compressing time). Fiber bundles were long, narrow and flexible elements, and it appeared that they could not be obtained by the conventional processes.

Characteristics of chromated copper arsenate-treated wood ash

The combustion of recovered wood from construction and demolition waste as biomass fuel is a common practice. When chromated copper arsenate (CCA)-treated wood is present as part of the wood fuel mix, concentrations of arsenic, chromium, and copper become elevated in the ash. The objectives of this study were to estimate the fraction of CCA-treated wood needed to cause the ash to fail regulatory guidelines and to test a series of solvents for the purpose of extracting the metals from the ash. Ash samples were prepared in an industrial furnace using samples of CCA-treated wood, mixtures of CCA-treated wood and untreated wood, and recycled wood waste collected at construction and demolition recycling facilities. Regulatory guidelines were evaluated by measuring total metals concentrations (using neutron activation analysis) and by conducting standardized leaching tests (toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP)) on the ash. Ten different solvents, ranging from distilled water to strong acids, were also tested for their ability to extract metals. Results of this study indicate that metal concentrations (chromium plus copper plus arsenic) can be as high as 36% of the ash by weight for treated wood samples containing high retention levels (40 kg/m 3) of CCA. All ash samples from the combustion of 100% CCA-treated wood and mixtures containing 5% CCA-treated wood leached enough arsenic (and sometimes chromium) to be characterized as a hazardous waste under US regulations. Concentrated nitric acid, which was the most effective solvent tested, was capable of removing between 70 and 100% of the copper, between 20 and 60% of the chromium, and 60 and 100% of the arsenic for samples characterized by low retention levels. A particular finding of interest was the efficiency of distilled water and other weak solvents to extract measurable amounts of chromium, especially for ash samples containing low retention levels of CCA. Citric acid was particularly effective at removing arsenic (between 40 and 100%) for ash samples produced from wood containing low CCA retention levels.

Detection of Inorganic Wood Preservatives on Timber by near Infrared Spectroscopy

The recycling of waste wood causes great problems due to the variety of toxic wood preservatives, varnishes and paints used. The fast and reliable distinction and sorting of treated and untreated wood on demolition sites could open new ways of wood recycling, e. g. for the production of chip boards. For this purpose, prepared wood samples treated with inorganic wood preservatives (arsenic, boron, copper salts) were investigated by near infrared-spectroscopy. In most cases, treated wood samples could be distinguished from untreated ones. Furthermore the type of wood preservative could be identified. The observed spectral features are electronic absorption bands and changes in the OH–band due to interaction with salt molecules.

大阪市における建設系廃木材の排出・処理実態と再資源化への課題

大阪市における建設系廃木材の排出・処理実態と再資源化への課題