Treated Wood Waste Research Articles

Structure Formation in Engineered Wood Using Wood Waste and Biopolyurethane.

This research aims to find suitable processing methods that allow the reuse of wood waste to produce wood waste-based engineered wood logs for construction that meet the strength requirements for structural timber for sawn structural softwood. Three types of wood waste were examined: wood packaging waste (W), waste from the construction and furniture industry (PLY), and door manufacturing waste (DW). The wood waste was additionally crushed and sieved, and the granulometric composition and shape of the particles were evaluated. The microstructure of the surface of the wood waste particles was also analysed. A three-component biopolyurethane adhesive was used to bind wood waste particles. An analysis of the contact zones between the particles and biopolyurethane was performed, and the adhesion efficiency of their surfaces was evaluated. Analysis was performed using tensile tests, and the formation of contact zones was analysed with a scanning electron microscope. The wood particles were chemically treated with sodium carbonate, calcium hypochlorite, and peroxide to increase the efficiency of the contact zones between the particles and the biopolyurethane adhesive. Chemical treatment made fillers up to 30% lighter and changed the tensile strength depending on the solution used. The tensile strength of engineered wood prepared from W and treated with sodium carbonate increased from 8331 to 12,702 kPa compared to untreated waste. Additionally, the compressive strength of engineered wood made of untreated and treated wood waste particles was determined to evaluate the influence of the wood particles on the strength characteristics.

Graphene Derived from Municipal Solid Waste.

Landfilling is long the most common method of disposal for municipal solid waste (MSW). However, many countries seek to implement different methods of MSW treatment due to the high global warming potential associated with landfilling. Other methods such as recycling and incineration are either limited to only a fraction of generated MSW or still produce large greenhouse gas emissions, thereby providing an unsustainable disposal method. Here, the production of graphene from treated MSW is reported that including treated wood waste, using flash Joule heating. Results indicated a 71%-83% reduction in global warming potential compared to traditional disposal methods at a net cost of -$282 of MSW, presuming the graphene is sold at just 5% of its current market value to offset the cost of the flash Joule heating process.

Decreasing the urban carbon footprint with woody biomass biochar in the united states of america

Urban centers are places with a high human population concentration, and they can pose social, economic, and environmental challenges. These challenges are accentuated by the increased use of available open space for housing and industrial expansion, leading to elevated energy consumption, increased pollution, higher carbon emissions, and, consequently, adverse effects on human health. Many of these issues also contribute to the acceleration of climate change. There are several ways to decrease these problems through the expansion of greenspaces that conserve biodiversity, decrease air pollution, improve human well-being, and reduce human health risks, while also allowing people to enjoy the benefits of ecosystem services. This review is aimed at professionals who can manage urban landscapes - including adjacent forests, urban parks, tree beds, or home gardens that produce biomass that, together with other non-chemically treated wood waste, could be used to produce and use biochar. Biochar-amended soils provide the benefits of increased carbon sequestration, water retention, and soil productivity and can also decrease stormwater runoff. In addition, a small number of cities around the world have adopted biochar as a nature-based solution to decrease the impacts of climate change. We point out the opportunities and benefits of converting urban wood waste into biochar, how cities can improve their green environments, and, at the same time, produce energy from waste that would otherwise end in landfills with no use or value. Finally, based on previous assessments of wood waste in the United States of America, we estimate the biochar potential to sequester CO2.

A Comparative Study on Heavy Metal Removal from CCA-Treated Wood Waste by Yarrowia lipolytica: Effects of Metal Stress.

Bioremediation is an effective way to remove heavy metals from pollutants. This study investigated the effects of Yarrowia lipolytica (Y. lipolytica) on the bioremediation of chromated copper arsenate (CCA)-treated wood wastes. Copper ions stressed the yeast strains to improve their bioremediation efficiency. A comparison of changes in morphology, chemical composition, and metal content of CCA wood before and after bioremediation was conducted. The amount of arsenic (As), chromium (Cr), and copper (Cu) was quantified by microwave plasma atomic emission spectrometer. The results showed that yeast strains remained on the surface of CCA-treated wood after bioremediation. The morphologies of the strains changed from net to spherical because of the Cu2+ stress. Fourier-transform infrared spectroscopy showed that carboxylic acid groups of wood were released after removing heavy metals. A large amount of oxalic acid was observed when the optical density (OD600nm) was 0.05 on the 21st day. Meanwhile, the highest removal rate of Cu, As, and Cr was 82.8%, 68.3%, and 43.1%, respectively. Furthermore, the Cu removal from CCA-treated wood increased by about 20% after Cu2+ stress. This study showed that it is feasible to remove heavy metals from CCA-treated wood by Y. lipolytica without destroying the wood structure, especially by copper-induced Y. lipolytica.

Characterization of chemically treated waste wood fiber and its potential application in cementitious composites

In recent years, the utilization of various fibers in cementitious composites gained remarkable popularity worldwide. Unlike well-known fibers, this study focused on examining the incorporation of waste wood fiber (WWF) assorted from construction and demolition sites into the cementitious matrix. In the first stage of the study, alkali-treatment of the WWF was carried out with different concentrations of sodium hydroxide (NaOH) solution (i.e., 1.0 M, 2.0 M, 2.5 M, 5.0 M, 10.0 M) and treatment durations (i.e., 2 h, 4 h, 6 h, 12 h) to eliminate impurities and enhance fiber properties and fiber-matrix compatibility through surface treatment. To investigate alkali-treatment efficiency, microstructural analyses were conducted on the untreated and alkali-treated WWFs by Scanning Electron Microscopy and Fourier Transform Infrared Spectrophotometer measurements. Afterward, physical and mechanical performance assessments were conducted by water absorption test, compressive and four-point bending tests on the WWF-incorporated cementitious composites to monitor the compatibility behaviour of the WWF-matrix interface. Microstructural examinations showed that after the alkali treatment, impurities (i.e., painting, hemicellulose, lignin, etc.) on the WWF surface were successfully removed; however, higher alkali concentrations (beyond 5.0 M) and longer treatment duration (after 6 h) lead to deterioration, fragmentation, and a more heterogeneous structure due to the degradation of long cellulosic chains of WWF. Four-point bending test results showed that the flexural strength capacity of 2.5M-2 h-WWF-composite was 7.9 MPa, which was higher than untreated WWF-composite and plain mortar by 34.7% and 39.8%, respectively. Furthermore, the 2.5M-2 h treated WWF composite had the highest compressive strength of 46.3 MPa, which was higher than plain mortar, and the untreated WWF composite by 6.4% and 21.5%, respectively. The elimination of impurities such as painting, lignin, hemicellulose, and other inorganic compounds at the optimal alkali treatment concentration and time increases the WWF surface area and strengthens the fiber-matrix interface adhesion, resulting in a stronger matrix-WWF interface connection and an increase in load-carrying capability. The study's findings are believed to encourage the usage of alkali-treated WWF in cementitious matrix with improved mechanical performance and high waste upcycling.

Copper-Doped Carbon Nanodots with Superior Photocatalysis, Directly Obtained from Chromium-Copper-Arsenic-Treated Wood Waste

An ecofriendly approach was developed for preparing copper-doped carbon dots (CDs) with superior photocatalysis using chromium-copper-arsenic (CCA)-treated wood waste as a precursor. Original wood (W-CDs), CCA-treated wood (C-CDs), and bioremediation CCA wood (Y-CDs) were used as the precursors. The chemical composition and structural, morphological, and optical properties, as well as the photocatalytic ability of the synthesized CDs varied with wood type. The C-CDs and W-CDs had similar characteristics: quasispherical in shape and with a diameter of 2 to 4.5 nm. However, the Y-CDs particles were irregular and stacked together, with a size of 1.5-3 nm. The presence of nitrogen prevented the formation of an aromatic structure for those CDs fabricated from bioremediation CCA wood. The three synthesized CDs showed a broad absorption peak at 260 nm and a weak absorption peak at 320 nm. Proof of the model study for the fabrication of luminescent CDs from CCA wood waste for bioimaging was provided. The degradation rate of CD photocatalytic MB was 97.8% for 30 min. Copper doping gives the CDs electron acceptor properties, improving their photocatalytic efficiency. This study provides novel ways to prepare nanomaterials from decommissioned wood as a nontoxic and low-cost alternative to fluorescent dots.

Bioleaching of heavy metals from preservative-treated wood using Aspergillus tubingensis

Abstract Although fungal bioleaching with Aspergillus niger has been investigated to remove metal from treated wood wastes, toxicological concerns limit the practical use of the species, necessitating the search for non-toxic species with comparable or greater metal removal efficiency. The removal of metals from wood treated with chromated copper arsenate (CCA) and copper amine-based preservatives was investigated using the non-ochratoxigenic mold Aspergillus tubingensis in comparison to A. niger via bioleaching. Metals were bioleached for 10 days by immersing treated wood sawdust in fungal culture filtrates. Culture filtrates were prepared by growing fungi in malt extract (ME) and sucrose media and then filtering the fungal biomass. Oxalic acid and citric acid were the predominant organic acids in A. tubingensis culture filtrate in ME and sucrose media, respectively. Citric acid present in sucrose media was found to be a more effective leaching agent for metals from preservative-treated wood. Citric acid produced by A. tubingensis and A. niger in sucrose media removed nearly 95% of copper, 80%–85% of chromium, and arsenic from CCA-treated wood, and 80%–90% of copper from wood treated with copper amine-based preservatives. As a result of its non-toxigenic characteristics and high metal removal efficiency, A. tubingensis may be a useful fungus for bioleaching metal components from inorganic preservative-treated wood.

Compressive strength of light-weight concrete material made from treated wood waste as a coarse aggregate

The effect of replacing the conventional coarse aggregate with wood shavings was evaluated relative to the 28-day compressive strength of the concrete. Six groups were studied: group-1 represented the normal concrete (NC-CTRL1), group-2 (TW-CTRL2) comprised the specimens that had the replacement of the coarse aggregate with raw wood shavings, group-3, group-4, group-5, and group 6 represented the specimens that had the coarse aggregate as coated (treated) wood shavings with cement paste (group-3 and -4) and with tile adhesive paste (group-5 and -6), with and without the effect of the emulsifier, respectively. The density of the TW-CTRL2 concrete was 31.4% lighter than NC-CTRL1. However, the compressive strength of TW-CTRL2 was 75% of the NC-CTRL1, but within the acceptable limits stated in ASTM standards. The findings of this study showed a potential to use the produced concrete as concrete masonry unit when compared with the values reported in previous studies. Compared with TW-CTRL2, the compressive strength increased 45% and 20% for the coated wood shavings with cement and tile adhesive pastes, respectively. The effect of using the emulsifier in the coating process of the wood shavings increased the compressive strength by 20%, and reduced the voids of the concrete by 3%.

Valorization of Hazardous Organic Solid Wastes towards Fuels and Chemicals via Fast (Catalytic) Pyrolysis

The management of municipal and industrial organic solid wastes has become one of the most critical environmental problems in modern societies. Nowadays, commonly used management techniques are incineration, composting, and landfilling, with the former one being the most common for hazardous organic wastes. An alternative eco-friendly method that offers a sustainable and economically viable solution for hazardous wastes management is fast pyrolysis, being one of the most important thermochemical processes in the petrochemical and biomass valorization industry. The objective of this work was to study the application of fast pyrolysis for the valorization of three types of wastes, i.e., petroleum-based sludges and sediments, residual paints left on used/scrap metal packaging, and creosote-treated wood waste, towards high-added-value fuels, chemicals, and (bio)char. Fast pyrolysis experiments were performed on a lab-scale fixed-bed reactor for the determination of product yields, i.e., pyrolysis (bio)oil, gases, and solids (char). In addition, the composition of (bio)oil was also determined by Py/GC-MS tests. The thermal pyrolysis oil from the petroleum sludge was only 15.8 wt.% due to the remarkably high content of ash (74 wt.%) of this type of waste, in contrast to the treated wood and the residual paints (also containing 30 wt.% inorganics), which provided 46.9 wt.% and 35 wt.% pyrolysis oil, respectively. The gaseous products ranged from ~7.9 wt.% (sludge) to 14.7 (wood) and 19.2 wt.% (paints), while the respective solids (ash, char, reaction coke) values were 75.1, 35, and 36.9 wt.%. The thermal (non-catalytic) pyrolysis of residual paint contained relatively high concentrations of short acrylic aliphatic ester (i.e., n-butyl methacrylate), being valuable monomers in the polymer industry. The use of an acidic zeolitic catalyst (ZSM-5) for the in situ upgrading of the pyrolysis vapors induced changes on the product yields (decreased oil due to cracking reactions and increased gases and char/coke), but mostly on the pyrolysis oil composition. The main effect of the ZSM-5 zeolite catalyst was that, for all three organic wastes, the catalytic pyrolysis oils were enriched in the value-added mono-aromatics (BTX), especially in the case of the treated wood waste and residual paints. The non-condensable gases were mostly consisting of CO, CO2, and different amounts of C1–C4 hydrocarbons, depending on initial feed and use or not of the catalyst that increased the production of ethylene and propylene.

Lightweight cement composites containing end-of-life treated wood – Leaching, hydration and mechanical tests

A huge amount of treated wood waste containing hazardous substances is produced every year all over Europe that simply ends up in landfills. In this study, the authors investigate the practical feasibility of using end-of-life treated wood for producing innovative lightweight cement composites. For this purpose, wood waste from four different sources was characterised to assess the presence of leaching substances and to ascertain physical properties relevant to the production of cement composites. Afterwards, cement pastes containing, firstly, wood extractives, and later, wood particles were prepared to assess the compatibility between the wood and Portland cement binder. To improve the wood-cement compatibility, additional tests were carried out using extracted and chemically treated wood particles. The results were discussed in terms of hydration heat and mechanical properties. Finally, a concrete mix containing selected wood particles was produced for a preliminary examination of the effect of wood waste on the mechanical properties of a reference concrete.The results show that the concentration of leaching substances can vary significantly depending on the source of wood waste. Small variations were found in the hydration heat profile of different cement composites containing up to 10 %(w/w) of wood particles, contrasting with the significant reduction found in compressive strength. The results of the concrete mixes further show that the incorporation of wood particles significantly reduces the mechanical performance of the hardened material, though such composites can still be used in applications with low-structural requirements.

Electro-removal of copper, chromium, and arsenic from chromated copper arsenate treated waste wood

ABSTRACT Wood is a renewable material considered eco-friendly and used for various purposes. While wood treated with chromated copper arsenate (CCA) does not deteriorate, its final disposal may entail risks due to the concentration and toxicity of the components. The removal of CCA from wood can be achieved in different ways. This study focuses on the reduction of the concentrations of Cu, Cr, and As chemical species by the electro-removal technique, aiming to obtain biomass with low deleterious potential that would allow multiple uses or safe disposal in landfills. The analytical results showed reductions of 79.5, 87.4, and 81.3% in the mean concentrations of Cu, Cr, and As, respectively. It is worth mentioning the occurrence of the fungus Xylaria sp. after treatment 6 (60 min, 5 g, and 25 V), further suggesting that the method was effective. Samples of these fungi were identified from isolates by culture in medium, DNA extraction, and sequencing of the Internal Transcribed Spacer (ITS) region.

Copper extraction and recovery from alkaline copper quaternary and copper azole treated wood using sulfuric acid leaching and ion exchange or electrodeposition

Removing copper from treated wood waste would allow the waste to be reused instead of being disposed of in landfills. For that reason, a sulfuric acid leaching process for removing copper from wood waste treated with alkaline copper quaternary (ACQ) and copper azole (CA) was tested at pilot scale. This process, consisting of three 160 min leaching steps at room temperature using a 0.13 N H2SO4 solution followed by three water rinsing steps, allows the removal of 95% of the initial copper present in the treated wood (1890 ± 100 mg kg−1 for ACQ-treated wood and 1190 ± 170 mg kg−1 for CA-treated wood). This study focuses on Cu recovery and revalorisation by ion exchange and electrochemical deposition. Acidic leachates obtained from ACQ- and CA-treated wood contain 99 ± 22 mg Cu L−1 and 124 ± 24 mg Cu L−1, respectively. One chelating resin, Dowex™ M4195, is identified for efficient Cu recovery from acidic leachate and allows ≥76% recovery with a maximum exchange capacity of 0.51 mmol Cu g−1 for ACQ-leachate and 0.39 mmol Cu g−1 for CA-leachate calculated using the Langmuir isotherm. Continuous ion exchange treatment allows Cu recovery as a CuSO4 solution when using H2SO4 as the eluent, or as a Cu-MEA solution for reuse in wood treatment when using monoethanolamine (MEA) as the eluent. Both eluents are able to solubilize ≥99% of the Cu trapped by the resin with a final concentration factor between 40 and 50. In contrast, electrochemical treatment allows for up to 92% Cu deposition at 10 A after 90 min. However, a comparison of the value of recovered Cu and the cost of the electricity required for deposition encourages the use of a lower current (3 A and 90 min). Economic analyses of both processes are presented for a plant with a capacity of 100 000 tons of treated wood per year (ttw yr−1). Accounting for direct, indirect, and capital costs, the treatment of waste wood and the recovery of wood and Cu can generate a profit of 37 US$ ttw−1 using ion exchange and 65 US$ ttw−1 using electrochemical treatment.

Role of Biochar in Anaerobic Digestion Based Biorefinery for Food Waste

The effect of biochar addition on the anaerobic digestion (AD) of food waste was evaluated. From the five biochars tested, Fe, Co, Ni, and Mn were leached in very small quantities (less than 10 mg/kg), while a high amount of K (1510 and 1969 mg/kg) was leached from treated waste wood and willow tree pyrochar, respectively. AD batch experiments were performed at an inoculum:substrate ratio of 1:1, at 30 °C and under agitating conditions. The results showed that the biogas volume produced by the treatments with the brewery residue hydrochar and treated waste wood pyrochar was lower than the amount of biogas produced by the control with only food waste. The food waste supplemented with 1.5 mL of trace elements yielded the highest biogas of 588 mL/g COD (CH4 content - 48%). Furthermore, two identical upflow anaerobic sludge blanket (UASB) reactors, i.e. control reactor and biochar amended reactor, were operated at 30 °C, at organic loading rates (OLR) varying from 3.4 to 7.8 g COD/L.day. The average COD removal efficiencies of the control and the biochar-amended reactor were 47% and 77% at an OLR of 6.9-7.8 g COD/L.day, respectively. These study results clearly indicate that the type of biochar and trace elements concentration in biochar play a key role in determining the effectiveness of the biochar in enhancing biogas production from food waste.

The use of chemical and biological agents in the recovery of heavy metals from treated woods – A brief review

This manuscript provides a brief review about chemical and biological agents used to bioremediate treated wood waste. Wood preservatives have been used to increase wood’s useful life, because any species is subject to decay. Studies indicate that the disposal of treated wood after its service has drawn concern and scrutiny. Practices have included disposal in landfills or construction sites as well as destruction by burning, so it is apparent that more environmentally friendly options are needed. To mitigate these problems, acidic agents, fungi, and bacteria can be used as alternatives to remove heavy metals. At optimum temperature and concentration, acids play a major role in the removal process. The process is enhanced when a bioremediation technique is used after chemical extraction. In fact, bioremediation has been shown to be a remarkable technique for recovering copper, arsenic, creosote, and other compounds. The major drawback is the extensive duration of fungal activity for release of heavy metals.

Waste wood as bioenergy feedstock. Climate change impacts and related emission uncertainties from waste wood based energy systems in the UK

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 N2O 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 N2O 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 N2O during the energy conversion.

Life cycle assessment of paper production from treated wood

The potential health and environmental impacts associated with the improper management of chemically treated wood waste demands the adoption of recycling, and disposal practices. Chemically treated wood waste has several physical and chemical properties which makes it usable for the manufacture of another product to multiple use, among which the production of paper and fuel. This paper presents the initial life cycle assessment (LCA) study on wood waste used for paper production. The study boundary is limited with raw materials (raw wood or waste wood) processing and paper production itself, thus corresponds to “gate-to-gate” life cycle with a special focus on life cycle inventory data on waste wood treatment via hydrolysis process. The results of the analysis demonstrate competitiveness of the waste wood use for paper production vs. raw wood in such environmental categories as human health and ecosystem quality.

An extensive characterization of various treated waste wood for assessment of suitability with combustion process

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 38g/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 1.1g/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.

<b>Roughness study on homogeneous layer panels manufactured from treated wood waste

Natural resource exploration is growing, highlighting woods and joinery waste, wood industries and the like. This study presents homogeneous particleboard (PPH) roughness characterization manufactured from treated wood waste. Normative document with values of Brazilian Technical Standard Association ABNT NBR 8404 (1984), was adopted as a reference. The results show that the manufactured PPH showed roughness class N 10, with roughness values (Ra) of less than 12.5 microns.

Contaminated biomass fly ashes – Characterization and treatment optimization for reuse as building materials

The incineration of treated waste wood generates more contaminated fly ashes than when forestry or agricultural waste is used as fuel. The characteristics of these biomass fly ashes depend on the type of waste wood and incineration process parameters, and their reuse is restricted by their physical, chemical and environmental properties. In this study, four different fly ash types produced by two different incineration plants were analysed and compared to Dutch and European standards on building materials. A combined treatment was designed for lowering the leaching of contaminants and the effect of each treatment step was quantified. A pilot test was performed in order to scale up the treatment. It was found that chlorides (which are the main contaminant in all studied cases) are partly related to the amount of unburnt carbon and can be successfully removed. Other contaminants (such as sulphates and chromium) could be lowered to non-hazardous levels. Other properties (such as particle size, LOI, oxide and mineralogical compositions) are also quantified before and after treatment.

Investigation of emissions from thermal oxidation of waste wood samples using spectral methods

The objective of this study was to investigate the effects of chemical treatment and heating rate on the emissions released from various waste wood samples including untreated pine and chemically treated MDF, plywood and particleboard after thermal treatment. Emission characteristics of the samples were determined in situ by using their FTIR spectra. Some toxic and carcinogenic gases such as formaldehyde, isocyanate, ammonia and phenyl group were detected in emissions from low temperature combustion of treated samples. For this reason, urea-formaldehyde or melamine formaldehyde treated waste wood samples should be oxidatively pyrolysed at low heating rates and low temperatures to remove nitrogen-containing toxic compounds such as ammonia and isocyanate.