Timber Waste Research Articles

Removal of Cr(VI) from aqueous solutions using modified red pine sawdust

The adsorption of Cr(VI) from aqueous solutions on sawdust (SD), base extracted sawdust (BESD) and tartaric acid modified sawdust (TASD) of Turkish red pine tree (Pinus nigra), a timber industry waste, was studied at varying Cr(VI) concentrations, adsorbent dose, modifier concentration and pH. Batch adsorption studies have been carried out. Sawdust was collected from waste timber industry and modified with various amount of tartaric acid (TA) (0.1–1.5 M). The batch sorption kinetics has been tested and the applicability of the Langmuir and Freundlich adsorption isotherms for the present system has been tested at 25 ± 2 °C. Under observed test conditions, the equilibrium adsorption data fits the linear Freundlich isotherms. An initial pH of 3.0 was most favorable for Cr(VI) removal by all adsorbents. Maximum Cr(VI) was sequestered from the solution within 120 min after the beginning for every experiment. The experimental result inferred that chelation and ion exchange is one of the major adsorption mechanisms for binding metal ions to the SD. Percentage removal of Cr(VI) was maximum at the initial pH of 3.0 (87.7, 70.6 and 55.2% by TASD, BESD, and SD, respectively). Adsorption capacities range from 8.3 to 22.6 mg/g for SD samples.

Regressional modeling of electrodialytic removal of Cu, Cr and As from CCA treated timber waste: application to sawdust

Waste of wood treated with chromated copper arsenate (CCA) is expected to increase in volume over the next decades. Alternative disposal options to landfilling are becoming more attractive to study, especially those that promote re-use. The authors have studied and modeled the electrodialytic (ED) removal of Cu, Cr and As from CCA treated timber waste. The method uses a low-level direct current as the “cleaning agent”, combining the electrokinetic movement of ions in the matrix with the principle of electrodialysis. The technique was tested in eight experiments using a laboratory cell on sawdust of out-of-service CCA treated Pinus pinaster Ait. poles. The experiments differ because the sawdust was saturated with different assisting agents and different percentages of them. In order to select the best assisting agent in jointly removing the three metals and subsequently the best percentage of the selected assistant agent, a statistical analysis was made. First, three experiments were selected as being the best. Second, for the selected experiments, a polynomial model was found to describe the time evolution of the total concentrations of each metal in the electrolytes. Based on this modeling, a multi-treatment regression approach was further used to select the final range of experiments.

Slow pyrolysis studies for utilization of impregnated waste timber materials

The increasing environment protection requirements for waste timber materials attract interest regarding the use of traditional slow pyrolysis equipment, which is employed to produce charcoal, for their utilization, since the raw material is lump wood. After carbonization of creosote-impregnated pinewood sleepers, the amount of toluene solubles decreases from 28.5 to 0.81% in sapwood. Having investigated the toxic polycyclic aromatic hydrocarbons (PAHs) content in charcoals, we have found that it partly depends on the wood species, since there are essential differences in the toxic PAH quantities in non-impregnated birch and pinewood charcoals (22 and 145 mg/kg from the oven-dry mass, respectively). However, the greatest growth is induced by the creosote fraction—the charcoal from creosote-impregnated sapwood, where the creosote content is the highest, and the toxic PAH content reaches 289 mg/kg from the oven-dry mass. Much greater differences are observed for the benzo(a)pyrene concentrations, which are 0.31 and 0.57 mg/kg from the oven-dry mass for birch and pine charcoal, respectively, and reach 4.04 mg/kg from the oven-dry mass in the case of pine sleeper sapwood charcoal. In its turn, the pyrolysis of electric transmission line (ETL) poles impregnated with chromated copper arsenate (CCA) shows that arsenic is inevitably partially evaporated, hence is distributed between the solid residue and the gas–vapor phase. CCA does not demonstrate the catalytic action on the charcoal yield during analytical pyrolysis, and only a minor increase is obtained during slow pyrolysis.

Copper and Chromium Electrodialytic Migration in CCA-Treated Timber Waste

Chromated copper arsenate (CCA)-treated timber waste is hazardous for the environment due to the leakage of copper, chromium as well as arsenic to the soil and the groundwater. The study concentrates on electrodialytic removal of copper and chromium and their migration behavior in the wood chips and sawdust matrix in an applied electric field. The method is based on the movement of the charged particles in the electric field, enhanced by incubation with oxalic acid (2.5% w/w) and various placement of the contaminated waste in the electrodialytic cell area to analyze the distribution of chemicals in the proposed matrix. The method was tested in laboratory scale experiments where the CCA contaminated wood chips and clean sawdust were placed in various places of the cell, i.e., adjacent to the cathode and anode compartments and in the mid-section of the cell. The duration of each experiment was 14 days and the current was kept constant at 40 mA. During the electrodialytic treatment negative copper and chromium compounds were mostly found in the anolyte or accumulated in the anion-exchange membrane. The amount of positive compounds found in the catholyte is negligible. The placement of contaminated chips close to the anode and cathode showed that copper and chromium moved towards the positively charged anode. If placed in the mid section of the cell, significant amount of contaminants remained bound to the wood matrix or slightly migrated towards the anode. To predict the formation of copper and chromium species at certain pH and Eh, the computer-modeling program MTDATA to generate Pourbaix diagrams was used.

形状計測センサーを用いた廃木材リサイクルチップ配向角の測定

形状計測センサーを用いた廃木材リサイクルチップ配向角の測定

Premium fuel production from coal and timber waste

There is a significant amount of energy in the waste generated by the coal and timber industries. In the coal industry there is an energy loss mainly due to the discharge of fine coal to the waste impoundment. Despite the fact that the fine coal has the greatest cleaning potential, dewatering, handling and transportation concerns prevent its use as product in many cases. Likewise, sawdust generated from wood production has energy value but is only used as industrial boiler fuel when the transportation distance is relatively short. Wood waste is often discarded into cumbersome landfills due to uneconomical transportation alternatives. Recent research found that these two waste materials can be combined to provide a high-energy fuel, containing around 30.2 MJ/kg (13,000 Btu/lb), that can be easily handled and transported to end users.

Maximizing resource recovery from waste streams

AbstractResource conservation and waste management have become two sides of the same argument. According to the Institutefor Local Self Reliance in the US., the recycling revolution begun in the l960s was a reaction “to the levels of waste in our economy and the pollution and suffering these habits cause worldwide” [1,2]. However, the recycling targetsetting of the early 1990s was focused on diversion from landfill, and it has taken another 10 years for the focus to shift back to the resource values approach, driven largely by the application of Life Cycle Assessment to the waste management system.This paper examines materials in the waste stream to determine the “value proposition” in each material group, and to examine options for efficient resource use and recovery. Specifically, it discusses waste management issues associated with clean fill, food waste, timber waste, concrete and bricks, green waste, paper and board, metals, plastics, and glass.

Effects of future crop tree flagging and skid trail planning on conventional diameter-limit logging in a Bolivian tropical forest

Sustainable natural forest management initiatives in the lowland tropical forests of Bolivia require that cost-effective measures be identified to help maintain timber stand quality and reduce damage to advance regeneration during logging operations. This study considered the potential costs and benefits of including two ‘best’ management practices—the pre-harvest flagging of future crop trees (FCTs) and improved planning of skid trails—in adjacent 45 ha plots, in conjunction with conventional planned diameter-limit logging in a lowland tropical forest in the Department of Santa Cruz, Bolivia. The study also included a general assessment of FCT damage and timber waste associated with standard felling operations. The additional costs of flagging FCTs ≥30 cm DBH were estimated to be US$ 0.38/ha. FCT flagging significantly reduced damage by 20% in felling gaps and by 10% along skid trails that received 2–10 skidder passes. A mean directional error of ±35° per tree felled was observed for felling operations, indicating that damage to FCTs during felling could be reduced through implementation of directional felling techniques. Improved felling techniques could increase mean timber utilization by as much as 0.16 m 3 or US$ 3.20 per tree felled through reduced wood waste associated with stump pull, a common problem observed during felling operations. Pre-harvest skid trail planning increased costs an estimated US$ 1.46/ha, but reduced mean skidder “search times” (min/m 3 harvested) by 23% and unnecessary skid trails by 96%. Compared to normal harvesting operations, overall operational efficiency increased by approximately US$ 3.00/ha. Pre-harvest skid trail planning significantly reduced FCT damage along skid trails that received 2–10 skidder passes. The results of this study indicate that pre-harvest skid trail planning and improved timber felling techniques yield short-term financial gains relative to conventional management as well as potential long-term gains through FCT conservation and, therefore, warrant implementation. Forest certification groups should consider FCT flagging for inclusion in timber certification criteria for the region given its low cost and proven utility for maintaining timber stand quality.

Recycle Use of Charcoals Produced from Waste Timber

Recycle Use of Charcoals Produced from Waste Timber

Reduce, Reuse and Recycle of Waste Timber Produced by Agricultural Improvement Project

Reduce, Reuse and Recycle of Waste Timber Produced by Agricultural Improvement Project

Ash from timber waste as cement replacement material

Sawdust is a waste product from the timber industry. Research work carried out on the ash derived from the sawdust has confirmed its pozzolanic properties with a pozzolanic index value of 75.9%. This material compares favourably with fly ash and wastes from the oil palm industry. The only difference noticed is in the low content of Al 2O 3 (4.09%) and Fe 2O 3 (2.26%). Concrete mixes have been proportioned to have various percentages of cement replacement with sawdust ash (SDA) ranging from 0% to 30% by mass. Performance of the ash–portland cement mixture has been evaluated with respect to setting time, workability and compressive strength. From the results obtained, 10% replacement of cement with SDA shows good performance giving the desired workability and strength.

Improving solid waste reduction and recycling performance using goal setting and feedback

A multiple-baseline experiment design across waste streams was used to determine the effectiveness of a goal setting and feedback intervention in bringing about improved solid waste management performance on a sports stadium construction site in Australia. A desktop method was used to measure the volume of timber and construction waste disposed as landfill and recycled. A general index of material usage efficiency and two recycling indices were calculated. Performance was measured each fortnight and formal goal setting and performance feedback were introduced to the timber and concrete waste streams. The intervention was effective in reducing the volume of waste disposed as landfill and increasing material usage efficiency, indicating that solid waste was reduced at source or re-used. Recycling performance did not improve significantly with the introduction of the intervention. This may be due to the way in which construction workers perceive the costs and benefits of recycling.

Electrodialytic Removal of Cu, Cr, and As from Chromated Copper Arsenate-Treated Timber Waste

Waste of wood treated with chromated copper arsenate (CCA) is expected to increase in volume over the next decades. Alternative disposal options to landfilling are becoming more attractive to study, especially those that promote reuse. The authors have studied the electrodialytic removal of Cu, Cr, and As from CCA-treated timber waste. The method uses a low-level direct current as the “cleaning agent”, combining the electrokinetic movement of ions in the matrix with the principle of electrodialysis. The technique was tested in four experiments using a laboratory cell on sawdust of an out-of-service CCA-treated Pinus pinaster Ait. pole. The duration of all the experiments was 30 days, and the current density was kept constant at 0.2 mA/cm2. The experiments differ because in one the sawdust was saturated with water (experiment 1) and in the rest it was saturated with oxalic acid, 2.5, 5, and 7.5% (w/w), respectively, in experiments 2−4. The highest removal rates obtained were 93% of Cu, 95% of Cr, and 99% of As in experiment 2. Other experimental conditions might possibly optimize the removal rates.

Modified palm kernel shell clamp method for firing bricks

The continuing activities of finding and testing suitable alternative fuel sources for firing bricks in Ghana is reported by Kofi Obeng. Previously, the use of agricultural waste (palm kernel shells) as a fuel was reported (Building Research and Information, 25(3), 131-136). This study reports on advances made through the substitution of charcoal made from timber offcuts and waste instead of the use of firewood to ignite the palm kernel shells.

Fundamental aspects of electrokinetic remediation of soils

Biochars are considered potential sustainable sorbents to reduce the leaching of per- and polyfluoroalkyl substances (PFAS) from contaminated soils. However, biochar characteristics must probably be optimized to achieve useful sorption capacity. In the present work, eight waste timber biochars were produced, including biochars activated to different degrees, at different temperatures, and using both steam and CO2. In laboratory batch experiments, the eight biochars were amended to soil samples from two different horizons, with low and high total organic carbon (TOC, 1.6% and 34.2%, respectively), of a heavily PFAS-contaminated soil (1200–3800 μg kg−1 PFAStot), at varying doses (0, 0.1, 0.5, 1.0 and 5.0%). With a 5% amendment to the low-TOC soil, all eight biochars resulted in strongly reduced leachate PFAS concentrations (by 98–100%). At the same amendment dose in the high-TOC soil, leachate concentration reductions were more modest (23–100%). This was likely due to a strong PFAS-sorption to the high-TOC soil itself, as well as biochar pore clogging in the presence of abundant organic matter, resulting in fewer sorption sites available to PFAS. Reduction in PFAS leaching was proportional to the degree of activation and activation temperature. Thus, lower amendment doses of activated biochars were needed to reduce PFAS leaching to the same level as with the non-activated biochar. Activation however, came at a tradeoff with biochar yield. Furthermore, the adsorption ability of these biochars increased proportionally with PFAS-fluorocarbon chain length, demonstrating the role of hydrophobic interactions in reduction of PFAS leaching. Development of internal surface area and porosity was proposed as the main factor causing the improved performance of activated biochars. This study shows that woody residues such as waste timber can be used to produce effective sorbents for the remediation of PFAS-contaminated soil. It also highlights the desirability of sorbate and matrix-specific optimization of biochar production.

Biomass energy from harvesting to storage

Collection, like transport and storage, is one of the basic technical and economic components of the processes of converting Biomass into energy. In recent years much progress has been made in R&D and industrial appli cations for the collection of all types of Biomass resources/feedstock, which ranges from orchard prunings to tree-felling waste, from straw to seaweed, from specific energy crops to arable-farming residues of any kind. Though interesting results have certainly been achieved, many problems still remain, and their solution will largely influence the final use of these Biomass sources and residues. There are the problems of bringing out timber waste from inaccessible oak forests, and making the collection of algae and aquatic plants financially worthwhile j should ma chines be specially designed for this work j and what about the economic and social costs for a proper forest management policy such as forest fires, soil degradation and so on. The need to assess what positives advances have already been made in the Community's member countries, so that Community action in this sector can be directed most efficiently, prompted the Directorate-General for Energy of the Commission of the European Communities to organize this workshop in collaboration with the other departments active in this field.

Effects of logging on stream environments and faunas in Nelson

The effects of various logging practices on stream environments and faunas were studied at the Golden Downs State Forest in Nelson. Comparisons were made between the features of a control stream with an unmodified forest catchment and three streams whose catchments had been affected by different logging practices. Measurements were made of stream flow, water temperature, stream bed sedimentation, suspended sediment and dissolved solids concentrations, and the abundance of benthic invertebrates and fishes. Clearfelling to the stream's edge, together with inappropriate roading and bridging techniques, caused great changes in stream environments and faunas. Excessive amounts of waste timber and soil entered streams and stream bed loads, and suspended sediment and dissolved solid concentrations increased. In comparison to the control stream water temperatures increased in summer by up to 6.5cc and decreased in winter by as much as 2.5°c. In one stream the benthic invertebrate fauna was greatly modified; there was a reduction in the abundance of Plecoptera and certain Ephemeroptera nymphs, and an increase in the abundance of oligochaetes. chironomids, and Deleatidium nymphs. Fishes, Galaxias divergens and Anguilla dieffenbachi, were also reduced in numbers in this stream. In January 1971 numerous brown trout (Salmo trutta) and other fishes died in the Motueka River, and there are indications that this was due in part to low dissolved oxygen concentrations following excessive sedimentation of the river bed caused by unsatisfactory logging practices. In general, the physical and chemical changes found in the stream environments were similar to those found overseas, but those noted in the invertebrate and fish fauna were rather different, e.g., logging had different effects on the abundance of Diptera, Ephemeroptera, and Trichoptera, and on trout survival and migration. The data collected will be of some value in assessing the effects of this type of logging on other streams and their biotas in the Nelson region. A protective buffer strip of unlogged vegetation was left alongside one stream and the remainder of the catchment was clearfelled. In comparison to the other streams there was relatively little change in the aquatic environment and fauna. Although stream flows and nitrate concentrations were considerably higher than in the control stream, these differences may have been natural and not a consequence of the logging operations. Similar results have been found overseas, and it is concluded that provided measures are taken to reduce erosion, buffer strips will be effective in reducing the effects of logging operations on stream environments and their faunas in other forests throughout New Zealand.

Possibilities of Reducing the Soil and Water Pollution Using Agricultural and Forestry Solid Biomass

The polluting effect of wood sawdust left in nature acts especially on the environment due to biodegradation in time, under the action of bad weather, fungi and micro-organisms. 
 Forestry and agricultural waste can be transformed through a technological process in pellets, agricultural pellets or combustible briquettes, products which may be used for energetic purposes, leading to higher use of them, and to nature protection of natural pollution with these secondary products.
 Determination of the influences of uncontrolled timber waste storage on the environmental components regarding the soil's quality in a site located in an unarranged sawdust warehouse area led to marking out an insignificant level of pollution induced by the quality indicator of phenols in all the soil profiles analyzed. Concentrations of pollutants in the air (ammonia and hydrogen sulfide) were below the limit value laid down in STAS 12574-87, while the measured concentrations of powders (PM 10) were located in the area of limit values.

Traditional Methods of Dyeing Wool in Wales

The stage in production at which wool is dyed varies according to the preferences of the textile worker and the type of cloth to be woven. In some cases raw wool, sometimes scoured, sometimes in the grease is dyed before carding. In the past, this was done in large, open vats and the worker would stir the boiling dye and wool at frequent intervals with a pole. In the smaller rural factories, this method of dyeing still persists. At the Esgair Moel Mill from Llanwrtyd in Brecknockshire, now at the Welsh Folk Museum, for example, the usual method is to dye unwashed raw wool in a large 30-gallon copper vat. The dye vat is always heated with wood fires and there is a tradition in Brecknock that the best timber for heating purposes is alder, which up to 1939 could be obtained from the itinerant clog sole makers who frequently visited the alder groves of the county and sold waste timber locally. The practise of dyeing raw wool in the grease has a distinct disadvantage in that the rollers of the carding engines have to be cleaned at frequent intervals, to ensure that one colour does not contaminate another. This is particularly true where white wool follows a strongly coloured one through the carding set; indeed, some of the larger, late nineteenth century woollen mills in west Carmarthenshire installed two carding sets; the one for white wool, the other for coloured wool.