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Highlights • Wide area of sampling, four countries and five different companies. • A I-A III recycled wood has 6 times higher portion of non-wooden material than AI. • The most critical inorganic pollutants in recycled wood are Cl, Cr, Cu and Pb. • Concentrations of analyzed inorganic pollutants increase with smaller particle size. • Samples from sophisticated sorting systems have lower portion of other materials. Abstract Recycled wood is becoming an important material source for production of new materials and chemicals. Predominantly clean recycled wood should be used for the products with high added value. However, contamination of the recycled wood defines the potential end uses. Thus, it is of the huge commercial and environmental importance to monitor the contamination of the respective material. In the present research, we focused on concentrations of non-wooden materials in recycled wood and the presence of indicative inorganic pollutants, namely: chlorine (Cl), chromium (Cr), copper (Cu), zinc (Zn), lead (Pb), iron (Fe) and bromine (Br). Sampling of various qualities of commercially available recycled wood was performed for one year in recycling companies from Germany, Slovenia, Finland and UK. In addition to the above-mentioned long term monitoring, fraction analysis was also performed on selected batches. For nine different fractions, the water soluble part and lignin content were additionally determined. The results showed that high quality recycled wood had low shares of non-wooden materials and only a few samples exceeded the limit values for inorganic pollutants prescribed by German ordinance Altholzverordnung or EPF standard. On the other hand, mixed recycled wood, of lower quality contained a significantly higher portion of non-wooden material (up to 3%). These mixtures also had higher concentrations of inorganic pollutants. More than 85% of samples exceeded the limit concentration prescribed by the German ordinance Altholzverordnung for recovered wood for at least one of the analysed chemicals. The concentration of chemical elements in samples from nine different size fractions negatively correlated with the particle size in the fractions. The same trend was also observed for the soluble part and the lignin content. In general, it can be concluded that recycled wood deriving from larger annual process capacity volumes with sophisticated sorting systems, contains less non-wooden material and can provide clean wood. On the other hand, the mixed recycled wood contained high concentrations of inorganic elements, regardless of the origin or sorting system. [ABSTRACT FROM AUTHOR]

The results of the experimental release of the test batches of fuel briquettes from carbon-containing products (waste coal and wood sawdust) are presented: by-product. The technical characteristics of fuel briquettes from the waste coals of different regions were determined. Data on the combustion of fuel briquettes from the test batches are given. The theoretical aspects of the formation of the structure and properties of fuel briquettes are considered. The practical significance of the production of fuel briquettes from the carboncontaining products as potential energy sources is demonstrated. [ABSTRACT FROM AUTHOR]

Waste wood (WW) was used as feed stock in an ethanol organosolv treatment to isolate lignin. The effects of treatment conditions (temperature, concentration of sulfuric acid and reaction time) on lignin yield were investigated using response surface methodology (RSM). Lignin yield was positively influenced by temperature and concentration of sulfuric acid but not by reaction time. The maximum lignin yield (12.46 g/100 g of dry wood with 44.25 % recovery) was achieved at 178.2ºC and 2.32 % H2SO4. Gel permeation chromatography showed that the isolated WW-lignin had low molecular weights. From the Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance spectra, WEB-lignin was estimated to have more guaiacyl (G) units than syringyl (S) units, showing high purity. The ethanol organosolv treatment offers the possibility of using isolated WW as an untapped source of lignin. [ABSTRACT FROM AUTHOR]

Abstract: A natural wood sample and two waste wood samples were investigated by thermogravimetry and the emerging pyrolysis gases were analyzed by coupled Fourier transform infrared spectroscopy and mass spectrometry (FTIR‐MS) analyzers. The mass loss curves, represented by the differential thermogravimetry signals, show different structures indicating different compositions of the initial samples. The waste wood samples were found to emit pyrolysis gases with some nitrogenous species, while in case of the natural wood samples, no nitrogen‐containing pyrolysis gases were detectable. The results can be used to extend an existing simulation model for the pyrolysis of waste wood. [ABSTRACT FROM AUTHOR]

Considering the urgent need to shift to low carbon energy carriers, waste wood resources could provide an alternative energy feedstock and at the same time reduce emissions from landfill. This research examines the climate change impacts and related emission uncertainties of waste wood based energy. For this, different grades of waste wood and energy application have been investigated using lifecycle assessment. Sensitivity analysis has then been applied for supply chain processes and feedstock properties for the main emission contributing categories: transport, processing, pelletizing, urea resin fraction and related N 2 O formation. The results show, depending on the waste wood grade, the conversion option, scale and the related reference case, that emission reductions of up to 91% are possible for non-treated wood waste. Compared to this, energy from treated wood waste with low contamination can achieve up to 83% emission savings, similar to untreated waste wood pellets, but in some cases emissions from waste wood based energy can exceed the ones of the fossil fuel reference - in the worst case by 126%. Emission reductions from highly contaminated feedstocks are largest when replacing electricity from large-scale coal and landfill. The highest emission uncertainties are related to the wood's resin fraction and N 2 O formation during combustion and, pelletizing. Comparing wood processing with diesel and electricity powered equipment also generated high variations in the results, while emission variations related to transport are relatively small. Using treated waste wood as a bioenergy feedstock can be a valid option to reduce emissions from energy production but this is only realisable if coal and landfill gas are replaced. To achieve meaningful emission reduction in line with national and international climate change targets, pre-treatment of waste wood would be required to reduce components that form N 2 O during the energy conversion. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the kinetic parameters of pyrolysis of waste wood from reforestation: Eucalyptus benthamii (EB), Eucalyptus dunnii (ED) and Pinus elliottii (PN). The kinetic study was performed using the Friedman, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), Starink, and Vyazovkin methods from the experimental data at four heating rates (5, 10, 20 and 30 °C min −1 ). The Friedman method presented higher activation energy values ( E a ) when compared to the other methods ( E a EB  = 142.98 kJ mol −1 , E a ED  = 147.71 kJ mol −1 , E a PN  = 155.46 kJ mol −1 ). The KAS, Starink and Vyazovkin methods resulted in approximate values of activation energy ( E a EB  = 132.83–133.31 kJ mol −1 , E a ED  = 137.51–137.98 kJ mol −1 , E a PN  = 145.24–145.70 kJ mol −1 ) due to the approximation equations with lowest relative errors. The simulation of curves using the kinetic parameters obtained with the Vyazovkin method showed that the decomposition process of EB and ED occurs as a multi-step process resulting in an unsatisfactory result for the simulation. On the other hand, for PN a satisfactory fit to the experimental data was obtained, which demonstrates its suitability for application to the modeling of thermochemical systems. [ABSTRACT FROM AUTHOR]

This letter deals with the in-situ determination of important inorganic gas phase species in high temperature gasification product gas. The fuels are waste wood and German hard coal which were co-gasified at 1500 °C in lab-scale experiments. The release of the vapour species 34 H 2 S + , 36 HCl + , 56 KOH + , 58 NaCl + , 60 COS + , 64 SO 2 + , and 74 KCl + was determined online by a Molecular Beam Mass Spectrometer. The experimentally determined data sets were compared to calculated data sets in order to distinguish the underlying release mechanisms. The release behaviour of the inorganics 34 H 2 S + , 36 HCl + , 60 COS + , 64 SO 2 + and 58 NaCl + cannot be attributed to simple mixing and dilution effect only. Further, it is shown that the release of these inorganics is significantly influenced by secondary reactions, e.g. competitive reaction with S and Cl. [ABSTRACT FROM AUTHOR]

The most important sources of biomass energy are currently coming from agricultural activity. A sizeable portion in production areas is waste wood after the winter cut of orchards and vineyards, which cover areas exceeding 30,000 ha in the Czech Republic. The most important are species like apples, peaches, apricots, plums, sweet cherries, sour cherries and grapevines. Average production of wood mass for individual species of fruit trees and grapevines ranges from 1,540 kg/ha up to 6,762 kg/ha, i.e. 1.5 t/ha to 6.8 t/ha. The calorific value for these species ranges from 14.70 to 16.39 MJ/kg, with moisture between 6 and 8%. The results show that the total measured energy potential of the fruit species-cultivated areas is 1,469.7 TJ for the whole Czech Republic.

co-gasification experiments with mixtures in various proportions of waste wood (WW) and sewage sludge (SS) were performed in a downdraft gasifier, in order to evaluate process performance and properties of gas and chars. Addition of SS improved the energy conversion efficiency and product gas yield, and minimised the formation of tars. Char production was greater, with formation of agglomerations inside the reactor. The optimal waste mixture contained 87.5 wt.% WW and 12.5 wt.% SS, generating a product gas yield of 2.9 m3/kg waste with a calorific value of 4.8 MJ/m3, and a tar production of 4.7 g/kg waste.

According to the statistic office of the European Union (Eurostat), Germany is the main producer of waste wood in Europe followed by France, United Kingdom, Italy and Finland. Based on the characteristics of the waste wood, it can be classified in four (4) categories: A I, A II, A III and A IV. This paper focuses in the A I waste wood since is the only category able to be used directly for both material and energy purposes without a previously pre-treatment. Currently, most of this waste wood is used for direct energy production due to the previous government legislation that promoted its use directly in incineration facilities. However, the newest Renewable Energy Act (EEG 2017) may promote the cascade-use of A I waste wood prior to be intended for energy purposes. Nonetheless, the government incentives to the energy sector is not the only bottleneck that the use of A I waste wood as raw material in the wood-based industry has to overcome. The peak availability, collection logistics (collection centers and transportation) and recycling facility location are some of the parameters that must be considered in order to design the “best” supply chain network for A I waste wood. This work presents a detailed description of the effect of the hierarchical strategic decision in the proper design of the waste wood supply chain. Additionally, the global picture of waste wood recycling in different European countries (UK, Italy and Finland) is briefly presented. [ABSTRACT FROM AUTHOR]

Recycling of waste materials is desirable to reduce the consumption of limited primary resources, but also includes the risk of recycling unwanted, hazardous substances. In Austria, the legal framework demands secondary products must not present a higher risk than comparable products derived from primary resources. However, the act provides no definition on how to assess this risk potential. This paper describes the development of different quantitative and qualitative methods to estimate the transfer of contaminants in recycling processes. The quantitative methods comprise the comparison of concentrations of harmful substances in recycling products to corresponding primary products and to existing limit values. The developed evaluation matrix, which considers further aspects, allows for the assessment of the qualitative risk potential. The results show that, depending on the assessed waste fraction, particular contaminants can be critical. Their concentrations were higher than in comparable primary materials and did not comply with existing limit values. On the other hand, the results show that a long-term, well-established quality control system can assure compliance with the limit values. The results of the qualitative assessment obtained with the evaluation matrix support the results of the quantitative assessment. Therefore, the evaluation matrix can be suitable to quickly screen waste streams used for recycling to estimate their potential environmental and health risks. To prevent the transfer of contaminants into product cycles, improved data of relevant substances in secondary resources are necessary. In addition, regulations for material recycling are required to assure adequate quality control measures, including limit values. [ABSTRACT FROM AUTHOR]

The quality of cellulose nanofibril (CNF) films is affected by processing and raw material related factors. The causes of potential excessive cellulose degradation during defibrillation that may directly affect the quality of CNF films may be assessed by cellulose viscosity, which need further investigations. This study aims to investigate the influence of cellulose viscosity and residual lignin of four different hardwood species ( Eucalyptus grandis - eucalyptus; Brosimum parinarioides - amapá; Parkia gigantocarpa - faveira; and Cordia goeldiana - freijó ) on water absorption of the subsequent CNF films. Viscosity of the unbleached and bleached pulps was measured by capillary viscosimetry after alkali and bleaching pre-treatments of the raw wood sawdust. Residual lignin was also determined for the bleached pulps. The films were obtained by casting method after pulp nanofibrillation through 10, 20, 30 and 40 passages in a mechanical defibrillator. The amount of water absorbed per film area (g/m 2 ) after water immersion of the CNF films for 60 s was determined and normalized by the thickness. Overall, CNF films obtained from pulps with residual lignin and higher viscosity, and hence lower degradation by the alkali and bleaching pre-treatments, showed lower water absorption. The lowest water absorption of B. parinarioides CNF films may be highlighted. For pulps with lower viscosity, water absorption continuously increased with the increase of passages through the defibrillator, possibly due to combined degradation of pre-treatments and nanofibrillation. This tendency was observed from 10 to 40 passages for eucalyptus CNF films and from 10 to 30 passages for P. gigantocarpa CNF films. [ABSTRACT FROM AUTHOR]

The most important sources of biomass energy are currently coming from agricultural activity. A sizeable portion in production areas is waste wood after the winter cut of orchards and vineyards, which cover areas exceeding 30,000 ha in the Czech Republic. The most important are species like apples, peaches, apricots, plums, sweet cherries, sour cherries and grapevines. Average production of wood mass for individual species of fruit trees and grapevines ranges from 1,540 kg/ha up to 6,762 kg/ha, i.e. 1.5 t/ha to 6.8 t/ha. The calorific value for these species ranges from 14.70 to 16.39 MJ/kg, with moisture between 6 and 8%. The results show that the total measured energy potential of the fruit species-cultivated areas is 1,469.7 TJ for the whole Czech Republic. [ABSTRACT FROM AUTHOR]

A representative set of treated waste wood was extensively characterized in order to evaluate its heterogeneity and its suitability with combustion process. Samples included both average samples made up of waste wood mixtures and specific waste wood classes. Untreated wood was also considered for comparison. As expected, neither heating value nor composition in C, H, O varied significantly compared to untreated wood. However, differences arose for minor elements, in relation with the chemical treatments undergone by waste wood. Particleboard was shown to be the main source of N with values up to 38 g/kg due to the presence of N-containing resins. Heavy metals like Ba, Ti or Zn were clearly associated to pigments used in painted wood or coatings and their amount reached respectively 2.6, 2.9 and 1.1 g/kg in painted wood. Cr and Cu were shown to come essentially from the chemical treatment undergone by impregnated wood with values of several thousands of mg/kg. A comparison between the minor elements contents found in waste wood and the specifications required in terms of feedstock composition and gas emissions in biomass combustion plants showed that the use of such feedstock would require either pretreatment before combustion to remove impurities or specific gas post-treatment. [ABSTRACT FROM AUTHOR]

Torrefaction of lignocellulosic waste wood and non-lignocellulosic sewage sludge and their blends was attempted. Effect of torrefaction temperature on mass yield, energy yield, HHV, elemental composition and gas yield was studied at a torrefaction temperature range of 200 to 450 °C. The decomposition rate of hemicellulose and organic component in lignocellulosic and nonlignocellulosic component played vital role in determining the characteristics of the torrefied products. In addition, the gaseous products from torrefaction were also analyzed. Comparatively low emission of carbon dioxide and thermal hydrocarbon is one of the major advantages in using the blends. [ABSTRACT FROM AUTHOR]

In this work, two sets of samples were considered: field samples collected from local waste wood and synthetic samples made by mixing clean wood (including oak, beech, poplar) with typical organic pollutants: creosote, polychlorinated byphenils (PCBs), pentachlorophenol (PCP), cypermethrin, dodecyl dimethyl ammonium chloride (DDAC). Vibrational spectroscopy techniques were tested to detect organic pollutants in wood items. Raman and infrared spectroscopies were showed as fast, non-destructive and non-invasive fingerprint techniques for detection of organic molecules. Associated with principal component analysis, we have shown the evidence of quick detection of and discrimination of polluted wood items by kinds and versus concentration. [ABSTRACT FROM AUTHOR]

Increasing scarceness of primary raw materials leads to a heightened focus on secondary resources. Deposits from urban infrastructure, mainly the building stock, are a potential major source of secondary resources. However, reliable information concerning available volumes and qualities is lacking. We analyzed incorporated amounts of wood in the building stock of south-east Germany, and calculated resulting streams of recovered wood in order to quantify potentially available volumes for an environmentally beneficial cascading utilization of these secondary resources. By applying a new method using data from sample buildings in regard to the quantity and quality of incorporated wood and statistical data concerning the building stock, the stock of wood based materials in buildings and the recovered wood resulting from demolishing for the year 2011 were calculated. We found that considerable amounts of recovered wood in suitable condition for a resource-efficient use in cascades can be expected to originate from the building stock: 25% of the recovered wood is suitable for re-use and 21% could be channeled into other high-value secondary applications. These first initialized concepts of a cascading utilization of recovered wood should be further refined and extended to utilize the existing potential to its optimum. [ABSTRACT FROM AUTHOR]

Dye-polluted wastewater is released from various industries, such as textile and paint industries. Among different reclamation techniques, adsorption has been widely used for dye removal. Carbonaceous adsorbents, such as graphene, are among the most sought-after compounds for adsorption applications because of their high specific surface area and adjustable surface features. In this study, graphene-like carbon (GLC) was prepared from biomass as it is a facile and eco-friendly approach. Biomass-derived GLC was prepared by pyrolyzing waste wood in the presence of FeCl 3 /ZnCl 2 as a eutectic binary mixture. Brunauer–Emmett–Teller (BET) and Raman analyses revealed that FeCl 3 had a template effect during pyrolysis, whereas ZnCl 2 acted as a pore former. Moreover, FeCl 3 and ZnCl 2 concentrations positively affected the BET value, regardless of the salt type. Further, waste wood-derived graphene-like carbon (WGLC) pyrolyzed at 900 °C with biomass: FeCl 3 : ZnCl 2 at a ratio of 1:2:1 (WGLC-121) showed the highest specific surface area (2073.78 m2 g−1) and could remove >90 % of rhodamine B (RhB) and Congo red (CR) dyes. The pseudo-second order kinetic model showed a stronger correlation with the experimental data than the pseudo-first order model. While intra-particle diffusion was the rate-determining step in RhB adsorption, it did not influence CR adsorption. Further, the Freundlich model better explained the RhB (q max = 633.86 mg g−1) and CR (q max = 141.28 mg g−1) adsorption and revealed the superiority of WGLC-121 in dye removal compared to the previously reported adsorbents. The adsorption isotherm, energy, and thermodynamic parameters confirmed that the dyes were adsorbed through physisorption. Furthermore, the inter-molecular interaction between the RhB and CR molecules influenced the dye adsorption rate and isotherm. The findings of this study demonstrate the high potential of a binary mixture of FeCl 3 and ZnCl 2 for preparing carbonaceous adsorbents from waste wood to remove dyes from industrial wastewater. [Display omitted] • Wood-derived graphene-like carbon (WGLC) adsorbent was prepared using waste wood. • The role of FeCl 3 and ZnCl 2 in preparing of carbonaceous adsorbents was explored. • Pseudo-second order model correlated better with data than pseudo-first order model. • WGLC-121 showed high adsorptive properties for Rhodamine B and Congo red. [ABSTRACT FROM AUTHOR]

The objective of this paper was to provide a preliminary analysis of the utilization of energy derived from waste wood in Taiwan, a highly industrialized country with a high dependence (over 99%) on imported energy. The discussion focuses on the status of waste wood generation and its management over the past decade. Findings show that the quantities of biomass waste collected for reuse purposes in the industrial sectors of Taiwan has exhibited an increasing trend, from about 4000 tons in 2001 to over 52,000 tons in 2010. Although waste wood can be reused as a fuel and raw material for a variety of applications based on regulatory promotion, the most commonly used end use is to directly utilize it as an auxiliary fuel in industrial utilities (e.g., boilers, heaters and furnaces) for the purpose of co-firing with coal/fuel oil. The most progressive measure for promoting biomass-to-power is to introduce the feed-in tariff (FIT) mechanism according to the Renewable Energy Development Act passed in June 2009. The financial support for biomass power generation has been increasing over the years from 0.070 US$/kWh in 2010 to 0.094 US$/kWh in 2012. On the other hand, the environmental regulations in Taiwan regarding the hazard identification of wood-combusted ash (especially in filter fly-ash) and its options for disposal and utilization are further discussed in the paper, suggesting that waste wood impregnated with chromated copper arsenate (CCA) and other copper-based preservatives should be excluded from the wood-to-energy system. Finally, some recommendations for promoting wood-to-energy in the near future of Taiwan are addressed.

A considerable proportion (about 64%) of biomass energy is produced from woody biomass (wood and its wastes). However, waste wood (WW) is very often contaminated with metal(loid) elements at concentrations leading to toxicity emissions and damages to facilities during thermal conversion. Therefore, procedures for preventing and/or alleviating the negative impacts of these elements require further development, particularly by providing informative and supportive information regarding the phase transformations of the metal(loid)s during thermal conversion processes. Although it is well known that phase transformation depends on different factors such as elements’ vaporization characteristics, operational conditions, and process configuration; however, the influences of reaction atmosphere composition in terms of interactions and interferences are rarely addressed. In response, since Cu, Cr, and As (CCA-elements) are the most regulated elements in woody biomass, this paper aims to explore the possible interactions and interferences among CCA-elements themselves and with Ca, Na, S, Cl, Fe, and Ni from reaction atmosphere composition perspectives during the gasification of contaminated WW. To do so, thermodynamic equilibrium calculations were performed for Boudouard reaction (BR) and partial combustion reaction (PCR) with temperature ranges of 0–1300 °C and 0–1800 °C, respectively, and both reactions were simulated under pressure conditions of 1, 20, and 40 atm. Refinement of the occurred interactions and interferences reveals that Ni-As interactions generate dominant species As2Ni5 and As8Ni11, which increase the solid–gaseous transformation temperature of As. Moreover, the interactions between Ca and Cr predominantly form C3Cr7; whereas the absence of Ca leads to Cr2Na2O4 causing instability in the Cr phase transformation.

The aim of this study was to investigate the optimal temperature range for waste wood and the effect torrefaction residence time had on torrefied biomass feedstock. Temperature range of 200–400 °C and residence time of 0–50 min were considered. In order to investigate the effect of temperature and residence time, torrefaction parameters, such as mass yield, energy yield, volatile matter, ash content and calorific value were calculated. The Van Krevelen diagram was also used for clarification, along with the CHO index based on molecular C, H, and O data. Torrefaction parameters, such as net/gross calorific value and CHO increased with an increase in torrefaction temperature, while a reduction in energy yield, mass yield, and volatile content were observed. Likewise, elevated ash content was observed with higher torrefaction temperature. From the Van Krevelen diagram, it was observed that at 300 °C the torrefied feedstock came in the range of lignite. With better gross calorific value and CHO index, less ash content and nominal mass loss, 300 °C was found to be the optimal torrefaction temperature for waste wood.

In Germany, waste wood can be used in various ways. The main ones are recycling in particleboards and energy production if the quality is insufficient for material utilisation. For the decision of usage, it is necessary to determine the wood quality by measuring the concentrations of certain pollutants. If given legal limits are exceeded, energetic utilisation in heat and power plants is recommended. Waste wood is a heterogeneous material. Therefore, special attention has to be given to the sample preparation in order to achieve representative analytical results. This article investigates whether the sample preparation according to ISO 14780 is also useable for a highly heterogeneous material such as waste wood or if a method with better homogenisation is needed. Furthermore, the effect of outliers on the interpretation of measurement results is considered. For this purpose, two milling methods are compared concerning their homogenisation capability. The samples were milled to 4 mm and homogenised. From this total amount, one half was milled directly to 0.25 mm (full milled), while the other half was separated in a sample divider until 100 g of the sample remained (according to ISO 14780), which was milled to 0.25 mm (partial milled). The results show that both milling procedures do not achieve a satisfactory homogenisation of the sample. However, with a sufficient number of measurements, limit value monitoring can still be carried out, as individual outliers are not decisive in whether a limit value is exceeded or not. • Sample preparation (milling) according to ISO 14780 is as suitable for waste wood. • Organoleptic sorting of waste wood is not possible. • Outliers will not affect the entire results if the sample quantity is sufficient. • Two measurements are not sufficient for a reliable analytical result. [ABSTRACT FROM AUTHOR]

Waste wood represents as much a waste to dispose of as a secondary resource to exploit. Various studies have assessed the energy potential and/or climate impact of energy recovery from waste wood. This paper aims to assess the long-term potential of waste wood for energy production and greenhouse gas (GHG) emissions reduction in Switzerland. Material flow analysis (MFA) is applied for modelling the metabolism of wood and waste wood in the Swiss anthroposphere over one century. The energy and climate impacts are estimated for 32 scenarios which assume different forest harvesting variants and waste wood treatment options. The scenario analysis shows that waste wood treatment options are more beneficial in the long term in terms of energy production (by energy recovery from waste wood) and of GHG emission reduction than the increase in the quantities of waste wood generated in the future caused by the advocated strategies of increased forest harvesting. By using the Maximin criterion, the long-term optimal additional potential for energy recovery from waste wood is estimated at 2110 GWh/year of useful energy, which offers a reduction of 364 tonnes of CO 2 equivalents per year. As prerequisites, the nominal installed capacity of the waste wood boilers needs to be raised and their efficiency and as well as those of incineration plants need to be increased. In addition, the sustainable potential of Swiss forests must be fully exploited. This study identifies various recommendations for the optimal exploitation of energy recovery from waste wood. [ABSTRACT FROM AUTHOR]

The wood industry produces large amounts of wood waste. This waste usually contains a number of nonwood materials, such as paints or varnishes. In this study, the pyrolysis characteristics of wood waste containing synthetic, polyurethane, and polyester varnishes were investigated for conversion into renewable liquid fuels. The elemental analysis and higher heating values of the biooils were determined. The chemical compounds present in the bio-oils obtained at an optimum temperature were identified by gas chromatography/mass spectroscopy analysis. The product yields and compositions were affected by the types of varnishes. The maximum bio-oil yield of 46.7% was obtained from pyrolysis of waste wood containing polyester varnish at a final pyrolysis temperature of 500 °C. The bio-oil produced from wood waste containing varnishes was composed mainly of phenols, aldehydes, acids, ketones, alcohols, benzenes, and N-containing compounds. The phenols accounted for the largest amount of compounds in the bio-oils. Therefore, the bio-oil produced from varnished wood waste could be a potential substitute for biofuels and green chemicals. [ABSTRACT FROM AUTHOR]

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]

The increased demand for waste wood (WW) as fuel in Swedish co-combustion facilities during the last years has increased the import of this material. Each country has different laws governing the use of chemicals and therefore the composition of the fuel will likely change when combining WW from different origins. To cope with this, enhanced knowledge is needed on WW composition and the performance of pre-treatment techniques for reduction of its contaminants. In this study, the chemical and physical characteristics of 500 WW samples collected at a co-combustion facility in Sweden between 2004 and 2013 were investigated to determine the variation of contaminant content over time. Multivariate data analysis was used for the interpretation of the data. The concentrations of all the studied contaminants varied widely between sampling occasions, demonstrating the highly variable composition of WW fuels. The efficiency of sieving as a pre-treatment measure to reduce the levels of contaminants was not sufficient, revealing that sieving should be used in combination with other pre-treatment methods. The results from this case study provide knowledge on waste wood composition that may benefit its management. This knowledge can be applied for selection of the most suitable pre-treatments to obtain high quality sustainable WW fuels. [ABSTRACT FROM AUTHOR]

• Wood database library was established based on 3D Scanning technology. • Waste, under-used and off-cut wood can be recycled for SBD. • 3D scanning method allows collection of parametric wood data and geometric features. • Provides material sources for building design and construction practice. The increasing demand for social well-being and infrastructure development, along with the exploitation of physical resources and the depletion of natural ecological resources, have led to a series of environmental problems, such as global warming and climate change. As a result, the UN 2030 Sustainable Development Goals have called for the reduction in the impact of urban development on the environment and the creation of adaptive, inclusive and sustainable habitats. The circular economy (CE) is a new economic paradigm that contributes to sustainable socioeconomic development. It aims to lessen the extraction and acquisition of material resources through recycling and rationalise the allocation and reuse of social resources. For instance, recycling wood, a fundamental component of municipal waste, alleviates some pressure to extract raw materials and solves the dilemma of turning materials into waste. In this context, this study investigates five mills and logging sites around London as a source of material support. The findings highlight that wood recycling methods remain inadequate, with an excessive amount of wood being landfilled, downgraded and disposed without the possibility of reuse. The experiment completed the material collection of Waste, Under-use and Off-cut wood based on photogrammetry and laser scanning technology. According to the practical features found within the geometrical data, a material library was generated to wood select to the porosity requirements of the building. Results from the investigation illustrate how recycled wood components can be reintegrated into new construction as part of sustainable building design (SBD). [Display omitted] [ABSTRACT FROM AUTHOR]

In the Great East Japan Earthquake on March 11, 2011, large amounts of disaster waste were generated by the earthquake and subsequent tsunami. Much of the mixed wood waste was stored in a temporary storage facility for an extended period of time, and fire broke out due to spontaneous ignition. Consequently, it is now the practice that when a metropolitan epicentral earthquake occurs, disaster waste will be generated and stored locally. Fire caused by the same type of spontaneous ignition is a grave cause for concern. Thus, in order to prevent such fires, we evaluated the thermal behavior of the oxidation heat of the wood that was believed to be the cause of the heat generation in disaster waste. As a result of studies using TG-DTA and TAM, it was revealed that the thermal danger of wood increases due to increases in the temperature and in the concentration of unsaturated fatty acids in the wood. It is thought that the oxidation heat of the unsaturated fatty acids contained in the waste wood contributed to heat generation near 70 °C after heat generation by fermentative bacteria. [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]

Biochar, a solid byproduct generated during waste biomass pyrolysis or gasification in the absence (or near-absence) of oxygen, has recently garnered interest for both agricultural and environmental management purposes owing to its unique physicochemical properties. Favorable properties of biochar include its high surface area and porosity, and ability to adsorb a variety of compounds, including nutrients, organic contaminants, and some gases. Physical and chemical properties of biochars are dictated by the feedstock and production processes (pyrolysis or gasification temperature, conversion technology and pre- and post-treatment processes, if any), which vary widely across commercially produced biochars. In this study, several commercially available biochars derived from waste wood are characterized for physical and chemical properties that can signify their relevant environmental applications. Parameters characterized include: physical properties (particle size distribution, specific gravity, density, porosity, surface area), hydraulic properties (hydraulic conductivity and water holding capacity), and chemical and electrochemical properties (organic matter and organic carbon contents, pH, oxidation–reduction potential and electrical conductivity, zeta potential, carbon, nitrogen and hydrogen (CHN) elemental composition, polycyclic aromatic hydrocarbons (PAHs), heavy metals, and leachable PAHs and heavy metals). A wide range of fixed carbon (0–47.8%), volatile matter (28–74.1%), and ash contents (1.5–65.7%) were observed among tested biochars. A high variability in surface area (0.1–155.1 g/m 2 ) and PAH and heavy metal contents of the solid phase among commercially available biochars was also observed (0.7–83 mg kg −1 ), underscoring the importance of pre-screening biochars prior to application. Production conditions appear to dictate PAH content – with the highest PAHs observed in biochar produced via fast pyrolysis and lowest among the gasification-produced biochars. [ABSTRACT FROM AUTHOR]

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The gas products from gasification processes have been considered to have some limitations in gas composition and heating value from the previous studies. Gasification characteristics of sewage sludge and wood mixture were investigated using different mixing ratios with the purpose of better quality of gas product suitable for energy/power generation. The gasification experiment was performed by an indirectly heated fluidized bed reactor. As reaction temperature increased from 600 to 900 °C, the yield of gas product increased with higher generation of CO, H and CH by more activated gas conversion reactions. As the equivalence ratio increased from 0.2 to 0.4, composition ratio of CO increased while CO, CH, H decreased as expected. Several operating variables including mixing ratio of wood with dried sludge were also tested. From this initial stage of experiment, optimal operating conditions for the bubbling fluidized bed gasifier, could be considered 900 °C in temperature; 0.2 in equivalence ratio and 40 % in wood mixing ratio within test variables range. These results will be more thoroughly investigated for the application to the larger scale pilot 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]

Abstract: 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. [Copyright &y& Elsevier]

The use of waste wood as a fuel in power plants is becoming more widespread in Europe, because it is a renewable energy source with a lower cost than forest fuel. However it is more corrosive than coal and corrosion problems have arisen in the furnace wall area of a low NOx heat and power boiler. The furnace walls are made of a low alloy steel which has been coated in some parts with a nickel alloy to reduce corrosion. In this work, furnace tubes coated with a nickel alloy were compared to the uncoated tubes of the low alloy steel 16Mo3 after 3 years of exposure in the boiler. The nickel alloy coating and uncoated material were also compared with more controlled testing on a corrosion probe lasting for about 6 weeks. The corrosion rates were measured and the samples were chemically analysed by SEM/EDS/WDS and XRD methods. The corrosive environment was also modelled with Thermo-Calc software. The corrosion rates measured from the probe and tube samples of 16Mo3 agreed well with each other, implying linear corrosion rates. The results also showed that the use of nickel alloy coatings changes the corrosion mechanism, which leads to a dramatic reduction in the corrosion rate. The results are discussed in terms of the corrosion mechanisms and thermodynamic stability of the corrosion products. [ABSTRACT FROM AUTHOR]