Search

The goal of this study was to determine the quantity and quality of wood extracted from the structural parts of wooden buildings to facilitate the most appropriate allocation of the material. An additional aim was to provide a reliable and consistent characterisation procedure for recovered wood, according to its physical characteristics, such as dimensions, the presence of cracks etc. From a sample of recovered wood collected from the demolition of a wooden building in Espoo, Finland, it was found that around 30% of the total volume of material could be recovered for repurposing or remanufacturing into solid wood products, provided structural integrity can be ensured. The samples of recovered wood were relatively short compared to virgin timbers, averaging 88 cm. Further, it was determined that removing metal contaminants does not necessarily improve material recovery, because cracks, wane, warping, as well as machining the recovered wood to standard dimensions, impact material recovery the most. [ABSTRACT FROM AUTHOR]

Modern environmental and economic challenges in waste management require transition from linear to circular economic flow. In practice, this entails considerable challenges that include the change of material circle flux, the application of mathematical modelling and the use of life cycle thinking – also in the field of recovered wood (RW). To this end, the reverse logistics process model CATWOOD (CAscade Treatment of WOOD) with mechanistic modelling for detailed planning of the RW reverse flow with regular collection, innovative (cascade) sorting based on RW quality and environmentally sound recovery has been designed. As a decision support, the quantitative methods of life-cycle assessment (LCA) and societal life-cycle costing (SLCC) have been incorporated into the CATWOOD, which can choose among a few alternative scenarios. A case study has been performed in the Posavje region in Slovenia, which has discovered that reverse logistics scenarios for reuse are environmentally friendlier than those for recycling or energy recovery, but also more costly, mainly because of extensive manual labour needed and less heavy technology involved in sorting and recovery processes. Sensitivity analysis has exposed that modifying the values of the input parameters may change the final LCA and SLCC results in scenarios observed.

• The material stock analysis included residential houses in Finland in 2017. • Wood intensity values were used for calculation of wood in building stock. • Age distribution of buildings by gross floor area and mass of wood were calculated. • Detached houses showed high potential for cascading in terms of quantity. • Issues to the development of material stock analysis and several recommendations were noted. The aims of this study were to quantify the amount of wood in residential houses in Finland in 2017 that could be available for cascading, and to characterize the age distribution and gross floor area of the houses in the stock. Through a bottom-up material stock analysis, the mass of wood and the gross floor area of buildings in each building type and construction period were estimated. The study found that 10 million tons of wood are contained in the structures of residential houses built before 1969, equivalent to around 59% of the stock. Since much of this stock is nearing end of life, this material should soon become available for cascading so providing a significant potential resource. It was also found that, overall, the structural parts of residential houses embody 17.5 million tons of wood, of which around 9 million tons is, theoretically, reusable and recyclable. However, for effective reuse and recycling, further analysis of the quality, type and future availability of recovered wood is required. The current results could be used for material stock and flow analyses to help planning for the use of recovered wood. Further research is needed to fill in gaps in the time-series of the number and gross floor area of buildings constructed and their average gross floor area. Moreover, a material intensity analysis of Finnish buildings is needed to better quantify the wood used. [ABSTRACT FROM AUTHOR]

The growing production of wood-based panels and the linked consumption result in a need for substituting standard wooden raw materials. The shortage of wood availability, as well as the increasing prices and a trend towards more environmentally friendly materials and processes, have encouraged the producers of wood-based products to consider extending the life cycle of wood composites. In the present work, the influence of substituting pine with spruce for industrial high-density fiberboards with 5% of recovered fibers was studied. Samples containing 0%, 25%, 50%, and 100% spruce fibers were tested in their mechanical resistance and their interaction with water. Boards from all samples met relevant standard requirements; however, the addition of spruce caused a decrease in mechanical properties, with homogeneity having the most significant influence. The modulus of rupture dropped up to 6% and the internal bond for 47% for samples having 50% of spruce. The most significant drop (50%) was observed for surface soundness for samples made with 100% spruce. Regarding physical properties, swelling increased up to 19% with 50% spruce; on the other hand, its water absorption decreased for up to 12%. The addition of spruce to industrial high-density fiberboards also influenced the formaldehyde content negatively, with an increase of up to 21% with 50% spruce. [ABSTRACT FROM AUTHOR]

Abstract To establish a bioeconomy, the demand for renewable resources like wood is likely to increase. To satisfy the demand, cascading, i.e. the sequential use of one unit of a resource in multiple applications with energy recovery as the final step, is a key concept to improve the efficiency of wood utilization. Today, the systematic wood cascading is still in its infancies and limited to the downcycling of wood, i.e. the degradation of material quality. New recycling technologies are needed, which maintain the material quality at the beginning of the cascade chain and mobilize yet unused resources. Therefore, a new recycling technology for recovered solid wood from construction into glued laminated timber products was developed. 1 1 The process was developed in the research project 'Cascading Recovered Wood — CaReWood', funded within the European WoodWisdom-Net Research Programme. To identify the environmental and economic performance of the process, the eco-efficiency was assessed by the joint application of life cycle assessment (LCA) and life cycle costing (LCC). As reference system, the incineration of the recovered wood was analyzed, representing the common treatment for recovered wood from construction in Germany. System expansion was applied to solve multifunctionality. The results indicate that the recycling of recovered wood into glued laminated timber products is environmentally and economically viable and offers possibility for the production of value added products. The recycling further shows up to 29% of lower environmental impacts and 32% of lower costs compared to the incineration, if system expansion is based on wood energy. The operational processes required for the solid wood cascading are of minor relevance for the economic and environmental performance. Instead, primary technologies like glue lamination and the incineration are key drivers. In all considered scenarios, the material recycling has a 15–150% higher eco-efficiency compared to the incineration. In conclusion, the further development for the practical implementation of the recycling process is recommended to enhance the implementation of the cascading concept. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Wood recycling is common practice in most countries. Currently, recovered wood is used for relatively low value uses including energy generation, particleboard manufacture, animal beddings and landscape uses. This paper gives an overview of two research projects that aim to generate high-value products from recovered wood and thereby encourage even higher rates of wood recycling. One project is concerned with the extraction of nano-crystalline cellulose from waste MDF and the other produces laminated beams from recovered wood. [ABSTRACT FROM AUTHOR]

The main objective of this study was to find scientific arguments in favour of reusing recovered oak wood in order to reintegrate it in new types of structures. For this study six beams were selected, which had been recovered from a house built in 1831. Visual analysis revealed several defects and signs of degradation in the sapwood and inside the cracks. The recovered beams hadn’t been treated with any toxic chemicals. Bending strength, modulus of elasticity and compression strength parallel to the grain were investigated and microscopy and FTIR-ATR spectroscopy were used to check the quality of the apparently sound beam areas also used for the determination of mechanical properties. Macroscopic and microscopic analysis may not reveal any incipient fungal attack but FTIR analysis was proven to be effective. The obtained results open a new perspective for the future use of recovered old oak wood, due to the adequate mechanical properties and to the assumed means of eliminating degraded areas.

The circular economy is among the key contemporary policy goals both in Europe and in Finland. Therefore, sustainability and life cycle thinking are increasingly the center of attention. In addition, wood and bioproduct companies have faced many challenges in Finland and the closure or restructuring of many large-scale industrial sites have caused many regional changes for both society and the private sector. The EU's targets to promote the circular economy and become a recycling society bring about many changes and provide new opportunities. This study addresses two different components of circular economy development in the forest sector through case studies. The first case study was a regional study on sustainability driven competitive advantage within forest sector companies and the method applied was a questionnaire survey targeted at both large and small forest sector companies in the Kymenlaakso region. The second case study was about the potential for cascading recovered solid wood in wood products and wood working companies and the method employed was interviewing company and association representatives. The findings of the first case study indicate that material and energy efficiency are important in the context of circular economy and bioeconomy development. They also indicate the importance of EU and national level public steering and sustainability considerations and that there is a need for more focus on life cycle thinking in the future. The findings of the second case study indicate that without inducements, legislative obligations or demand from the construction sector or other customers, the potential for the wide-scale cascading of solid wood in Finland is very limited. The most promising cascading opportunities are the reuse and preparing for reuse of wooden packages and furniture. In addition, the results suggest that life-cycle-assessment for different end-of-life scenarios for solid wood products could give more reliable information about different options from an environmental point of view. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore potential cascading flows and the measures that could be taken to enhance cascading potential. The results reveal that the potential cascading flow needs to be considered in light of the length and condition of the wood recovered from buildings, rather than the cross-section. For instance, wood in the roof structure such as '1 × 4' or '1 × 6' was recovered with most of the original length intact and with minimal damage, which is suitable for direct reuse. In contrast, wood in walls, floors and ceilings such as '2 × 2', '2 × 3' or '2 × 8' was recovered in poor condition in terms of both length and the occurrence of damage. To enhance cascading potential, the development of the jointing systems and considering the reuse of whole elements of the unit parts should be further investigated. [ABSTRACT FROM AUTHOR]

Driven by the scarcity of non-renewable resources and a growing environmental awareness in Germany, the demand for wood could likely exceed its sustainable supply within the next decades. In response to this development, cascading, i. e. the sequential use of one unit of material in material applications with energy generation as final step, is expected to enhance the resource efficiency of wood utilization. In this context, the objective of this paper is to determine the resource consumption and resource efficiency of wood cascading compared to the use of primary wood to provide the same multiple functions. To account for resource use and calculate the efficiency, exergy analysis was applied. The exergy of a material is the potential work that can be obtained from the material in the natural environment. By using Exergy Flow Analysis, key drivers of exergy dissipation and thus hotspots for improvement were identified. Exergetic Life Cycle Assessment was applied to determine resource use and the resource efficiency at a life cycle level. The results indicate that cascading leads to less resource consumption compared to the use of primary wood, indicated by higher resource efficiency (46% vs. 21%) at life cycle level. The main resource saving potential through cascading arises from avoiding primary production in forestry systems. In conclusion, cascading reduces the primary resource extraction and makes wood utilization highly efficient. Exergy analysis proved to be a viable method to study the resource use of multifunctional cascading systems, although showing some limitations with respect to land use accounting. [ABSTRACT FROM AUTHOR]

In recent years, recovered wood that arises from the demolition of buildings has become a demanded raw material for the production of particleboards and energy. Similarly, several statistics and studies have demonstrated that timber was an important building material during the so-called “Wilhelminian time” and that its use has been increasing since the 1980s. We therefore assume that a considerable volume of timber is contained in the Austrian building stock that serves as a potential raw material. A central question that needs to be addressed in this context is what volumes of timber can be expected to arise from the demolition of residential buildings in the coming years. To answer this question, a generic dynamic material flow analysis model presented by Müller, (2005) is adapted to data available on the Austrian building stock and the timber contained. With the help of this model, different scenarios on the development of the timber contained in the Austrian building stock and its input and output flows are developed and presented for the years 2012–2100. The standard scenario shows that (1) the volume of timber stored in the building stock will increase steadily from approx. 32 M m 3 to approx. 50 M m 3 , and (2) the input of timber follows a wavelike behaviour within the frame of approx. 550,000 to approx. 750,000 m 3 /a. Furthermore, (3) the output of timber will increase slightly during the first two thirds of the period considered and indicates a steeper increase for the remaining period, subsequently rising from approx. 350,000 m 3 to approx. 650,000 m 3 in 2100. [ABSTRACT FROM AUTHOR]

Wood products follow the same cycle as other materials: manufacture, use and disposal. For certain applications, chemical additives are added to wood to increase its durability against biological and physical attack. At the end of life, waste wood is chipped or crushed before being recovered as raw material for new products or as fuel for energy. In recycled wood, there is the potential that some wood particles are contaminated by hazardous substances, such as organic or heavy metal preservatives. Therefore there is a need for a quality control method of assessing recovered wood that is on the one hand sufficiently precise and on the other not too expensive to preclude the use of recycling wood in to new products. This paper covers some preliminary research that is part of a large study that aims to develop a robust analytical method for recovered wood. However the extreme variability of recovered wood makes it difficult to develop such protocols on real recovered wood samples. Consequently, model chip piles with known contamination levels were created to simulate real world recovered wood samples.

The aim of this study was to understand the current situation of wooden C&DW in Finland through a survey conducted on the demolition of a case study building. The results revealed that the extent of damage to the recovered wood is more dependent on the location than on the dimension. The condition of recovered wood from an integrated unit part (e.g. exterior wall panel) tended to be worse due to the attachment of other materials (e.g. insulation, plastic sheet), while recovered wood in better condition could be obtained from independent parts (e.g. roof truss, exterior cladding). These results would indicate that the cascading potential for recovered wood should be discussed in terms of both cross-section and location. In particular, the wood used as exterior cladding seems to have good potential for cascading and this could help extend the target for cascading wood from purely wooden building to other buildings. [ABSTRACT FROM PUBLISHER]

The increasing demand for wood and the associated increased logging in Europe as well as changes in forest management towards hardwood-rich mixed forests lead to a shortage of wood supply. An example of a relatively unexploited sort of wood is waste wood. After an introduction to the overall wood supply in Europe, the special situation of waste wood usage in Germany is discussed. Both the legal but also the actual situation is presented. Here, particularly the potential contamination and impurities of the waste wood and its origin are discussed. [ABSTRACT FROM AUTHOR]

Wood products follow the same cycle as other materials: manufacture, use and disposal. For certain applications, chemical additives are added to wood to increase its durability against biological and physical attack. At the end of life, waste wood is chipped or crushed before being recovered as raw material for new products or as fuel for energy. In recycled wood, there is the potential that some wood particles are contaminated by hazardous substances, such as organic or heavy metal preservatives. Therefore there is a need for a quality control method of assessing recovered wood that is on the one hand sufficiently precise and on the other not too expensive to preclude the use of recycling wood in to new products. This paper covers some preliminary research that is part of a large study that aims to develop a robust analytical method for recovered wood. However the extreme variability of recovered wood makes it difficult to develop such protocols on real recovered wood samples. Consequently, model chip piles with known contamination levels were created to simulate real world recovered wood samples.

This is a discussion paper that presents the CaReWood process for recycling solid wood. The main aim of CaReWood is to develop and assess the viability of a method of reprocessing postconsumer wood that has a minimal impact on the cross-sectional area of the pieces. In other words, making glued and/or laminated wood products from recovered wood. Although a simple concept, its implementation is complex and so this paper provides a context and discussion of the factors that will influence putting the CaReWood process into practice. [ABSTRACT FROM AUTHOR]

The main objective of this study was to find scientific arguments in favour of reusing recovered oak wood in order to reintegrate it in new types of structures. For this study six beams were selected, which had been recovered from a house built in 1831. Visual analysis revealed several defects and signs of degradation in the sapwood and inside the cracks. The recovered beams hadn't been treated with any toxic chemicals. Bending strength, modulus of elasticity and compression strength parallel to the grain were investigated and microscopy and FTIR-ATR spectroscopy were used to check the quality of the apparently sound beam areas also used for the determination of mechanical properties. Macroscopic and microscopic analysis may not reveal any incipient fungal attack but FTIR analysis was proven to be effective. The obtained results open a new perspective for the future use of recovered old oak wood, due to the adequate mechanical properties and to the assumed means of eliminating degraded areas. [ABSTRACT FROM AUTHOR]

Cascading, the use of the same unit of a resource in multiple successional applications, is considered as a viable means to improve the efficiency of resource utilization and to decrease environmental impacts. Wood, as a regrowing but nevertheless limited and increasingly in demand resource, can be used in cascades, thereby increasing the potential efficiency per unit of wood. This study aims to assess the influence of cascading wood utilization on optimizing the overall environmental impact of wood utilization. By combining a material flow model of existing wood applications – both for materials provision and energy production – with an algebraic optimization tool, the effects of the use of wood in cascades can be modelled and quantified based on life cycle impact assessment results for all production processes. To identify the most efficient wood allocation, the effects of a potential substitution of non-wood products were taken into account in a part of the model runs. The considered environmental indicators were global warming potential, particulate matter formation, land occupation and an aggregated single score indicator. We found that optimizing either the overall global warming potential or the value of the single score indicator of the system leads to a simultaneous relative decrease of all other considered environmental impacts. The relative differences between the impacts of the model run with and without the possibility of a cascading use of wood were 7% for global warming potential and the single score indicator, despite cascading only influencing a small part of the overall system, namely wood panel production. Cascading led to savings of up to 14% of the annual primary wood supply of the study area. We conclude that cascading can improve the overall performance of a wood utilization system. [ABSTRACT FROM AUTHOR]

Purpose: A cascading utilization of resources is encouraged especially by legislative bodies. However, only few consecutive assessments of the environmental impacts of cascading are available. This study provides answers to the following questions for using recovered wood as a secondary resource: (1) Does cascading decrease impacts on the environment compared to the use of primary wood resources? (2) What aspects of the cascading system are decisive for the life cycle assessment (LCA) results? Methods: We conducted full LCAs for cascading utilization options of waste wood and compared the results to functionally equivalent products from primary wood, thereby focusing on the direct effects cascading has on the environmental impacts of the systems. In order to compare waste wood cascading to the use of primary wood with LCA, a functional equivalence of the systems has to be achieved. We applied a system expansion approach, considering different options for providing the additionally needed energy for the cascading system. Results and discussion: We found that the cascading systems create fewer environmental impacts than the primary wood systems, if system expansion is based on wood energy. The most noticeable advantages were detected for the impact categories of land transformation and occupation and the demand of primary energy from renewable sources. The results of the sensitivity analyses indicate that the advantage of the cascading system is robust against the majority of considered factors. Efficiency and the method of incineration at the end of life do influence the results. Conclusions: To maximize the benefits and minimize the associated environmental impacts, cascading proves to be a preferable option of utilizing untreated waste wood. [ABSTRACT FROM AUTHOR]

Three-layer polymeric diphenyl-methane-diisocyanate (pMDI)-bonded particleboards (PBs) were produced with different proportions of simulated recovered wood (rW) in the core layers (cLs) to assess the effect of rW on the formaldehyde (FA) release of PB. A pre-test was conducted on furniture and particle mixtures of rW to determine the range of expectable FA emission of rW. The FA content of the raw particle mixtures could be predicted from the contents of the individual raw material and did not change compared to the PB. FA content correlated strongly with PB-FA emission. It was possible to predict the maximum PB-FA contents, which should not be exceeded according to F**** and CARB 2 by linear regression models. At moderate and high total FA emission levels, the FA emission of the particle mixtures was approximately 60% higher than the emission of PB blocks. At low total FA level, the flask method and the gas analysis method exhibited different results with regard to the emissions from particles and their respective PBs. [ABSTRACT FROM AUTHOR]

The purpose of the investigations reported was a feasibility study of field asymmetric ion mobility spectrometry (FAIMS) applications for the characterization of recovered wood. Especially the treatment with organic wood preservatives represented by their active substances should be detected in concentrations commonly used for timber products. The following pesticides were determined: PCP, lindane, dichlofluanide, tolylfluanide, propiconazole, tebuconazole, IPBC (iodine-propyl-butyl-carbamate), K-HDO ((N-Cyclohexyl-diazeniumdioxy)-potassium) and fenoxycarb. The first step was to show that such compounds can be vaporized under moderate conditions. Solid-phase microextraction (SPME) was capable for sampling and enrichment. The reference analytics was made by gas chromatography coupled with mass spectrometry (GC-MS). Both, waste wood, in this case window frames from reconstruction work, and self-prepared doped wood samples were utilized. For analyzing the complex mixture of vaporized native and artificial ingredients of the lignocellulose material a chromatographic pre-separation was necessary. Hence, the second step was to study the behavior of active substances in the analysis with GC-FAIMS to clarify which peaks in positive and negative mode are dedicated to wood preservatives. At least one strong signal from every selected active compound was located for clear identification. With that knowledge, FAIMS was successfully applied for the distinction of natural and treated wood samples. The discrimination can be a basis for industrial sorting plants which could help to increase the contemporary amount of material usage of recovered wood for a more ecological and economical handling of natural resources. [ABSTRACT FROM AUTHOR]

Wood products follow the same cycle as other materials: manufacture, use and disposal. For certain applications, chemical additives are added to wood to increase its durability against biological and physical attack. At the end of life, waste wood is chipped or crushed before being recovered as raw material for new products or as fuel for energy. In recycled wood, there is the potential that some wood particles are contaminated by hazardous substances, such as organic or heavy metal preservatives. Therefore there is a need for a quality control method of assessing recovered wood that is on the one hand sufficiently precise and on the other not too expensive to preclude the use of recycling wood in to new products. This paper covers some preliminary research that is part of a large study that aims to develop a robust analytical method for recovered wood. However the extreme variability of recovered wood makes it difficult to develop such protocols on real recovered wood samples. Consequently, model chip piles with known contamination levels were created to simulate real world recovered wood samples. [ABSTRACT FROM AUTHOR]