•Hazardous heavy metal contents and the leaching behavior in 60 woody biomass fly ash.•95% of the woody biomass fly ash could be landfilled without special treatment.•The impacts of furnace type and ...fuel were statistically analyzed.•Ash produced from waste wood combustion had higher heavy metal contents.•Selenium can be a concern in beneficial use of woody biomass fly ash.
In efforts to reduce net CO2 emissions, the use of woody biomass as a fuel for power generation has grown rapidly. However, this practice is expected to generate large amounts of combustion ash. To support the subsequent use and disposal of combustion ash, it is important to understand its hazardous heavy metal (HHM) contents and leaching behavior. Therefore, we investigated the impacts of furnace type and fuel on HHM contents and leaching behavior based on 60 types of woody biomass fly ash (WBFA). A safety assessment of WBFA as fertilizer based on HHM contents revealed that 20% of the WBFA samples exceeded the prescribed standards. Therefore, WBFA would require preprocessing before reuse as fertilizer. The leaching test results showed that 95% of the WBFA samples could be landfilled as industrial waste without special treatment. However, prior to reuse in construction materials or soil amendments, it would be necessary to remove or fix HHMs to prevent leaching. Overall, WBFA generated from the combustion of waste wood as fuel tended to have higher HHM contents and leachate concentrations than WBFA from other woody biomass-based fuel types.
Adoption of renewable energy sources such as biomass has been increasing worldwide. In this study, fast pyrolysis as an acceptable and viable method to get renewable bio-oil and biochar is used. ...Different temperatures and N2 flow velocities were used in the fast pyrolysis process to evaluate the pyrolysis yield of biochar and bio-oil. The waste wood and pig manure were utilized to prepare biochar and bio-oil. X-ray fluorescence, X-ray diffraction, high-pressure liquid chromatograph, Micro confocal laser Raman spectrometer, Fourier transform infrared spectrometer, and dynamic shear rheometer were used to measure the chemical compositions, structure, and pyrolysis yield of biochar and bio-oil. The obtained results indicate that pyrolysis temperature increases the purity of inorganic oxide in biochar and N2 flow velocity promotes the yield of carbon in biochar. The increase of N2 flow velocity would increase the acid property of bio-oil and damage the products yield of bio-oil. It was also observed that biochar could remarkably alter the fundamental performances of petroleum asphalt including penetration, softening point, ductility, viscosity, and complex modulus. The most important is that the upgraded bio-oil can be used to replace partly or fully the petroleum asphalt which is a promising biomass application.
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•Waste wood and pig manure were used as biomass for fast pyrolysis.•Pyrolysis temperature affects the pyrolysis yield and chemical properties of pyrolysis products.•Bio-oil can be used to replace partly or fully the petroleum asphalt.•Biochar and bio-oil can be co-used to asphalt modification and replacement.
Sustainable structural lightweight concrete has been produced using the waste of wood particles found in disposal areas of wood factories and carpenters. These wastes form a bunder on the environment ...and recycling them will provide a gain to the environment and the economy. Wood particles of aggregate size have been used in variation with percentages (0%,5%,7%,10%, 12% and 15%) of the cement weight. The concrete produced becomes light weight reaching 1600 kg/m3 (33% reduction). The workability kept constant by controlling mix properties of SP doses. The compressive strength ranged between 60 MPa for control samples to 30 MPa for 15% wood particle concrete, a max reduction of 54% is resulted, however the overall reduction was 42%. Applying superplasticizer SP has improved the results and reduction becomes 22% overall. The corresponding flexural strength ranged between (12 MPa to 22 MPa), with overall increase of 7% over the control specimens increased to 34% when using SP.These findings provide encouragement to use the wood particles lightweight concrete in structures. However, durability remains the main concern. The concrete should be protected from severe exposure and humidity. Therefore, it is recommended to be used in indoor exposure.
The evaluation of thermochemical characteristics and the development of kinetic model for pyrolysis of waste biomass are more challenging. In this study, the mass losses, intermediates evolved and ...products formed during pyrolysis of waste wood biomass were determined by coupling DSC/TGA-DTG/GC-MS/FTIR to improve the understanding of conversion processes and decomposition characteristics. The improved non-isothermal kinetics method was proposed by introducing the function of mechanisms, the activation energies and pre-exponential factors were estimated iteratively by regression to enhance modeling accuracy. The results indicated the gases of CO, CO2, CH4, H2 and the liquids of N-containing organics, esters, ketons and carboxylic acids were the most dominated products evolved. The pyrolysis of waste wood biomass could be divided into three phases, and with the increase of heating rates, the caloric requirement for pyrolysis was greatly increased. The random nucleation and one-dimensional diffusion predicted accurately the main (second) and third phases in the pyrolysis of waste wood biomass and waste camphor presented lower activation energies than waste bamboo.
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•Pyrolysis of waste wood is studied by DSC/TG-DTG/GC-MS/FTIR.•Mass loss and energy requirement of pyrolysis are determined by DSC/TGA-DTG.•Gases and liquids of pyrolysis are analyzed by FTIR, GC-MS.•Improved kinetics method is derived to enhance the accuracy of model.
•Inadequacies in the disposal methods lead devastating environmental deprivation.•Cement manufacturing contributes to approximately 7% of global CO2 emission along.•Major reduction in the carbon ...footprint is attained due waste wood use in mortars.•The use wood powders crucially enhance the mechanical properties of cement mortars.•Waste wood use in mortars offers a greener disposal lane for industrial wastes.
Significances of reducing the climate change through the mitigation of global warming potentials are implicitly affiliated with the energy consumption, carbon dioxide emissions, and associated environmental hazards. In the light of reducing these adverse effects on environmental sustainability, waste wood materials are partially substitute in cement mortars as a greener alternative to the existing disposal routes. The paper comprehensively investigates the utilisation of waste wood materials in the forms of wood powders and wood fibres in cement mortars to re-generate the waste wood into value added construction materials. Although the optimum cases often appear to be attained when wood powders are used as sand replacement, it is emphasized in the paper that the reduction in strength and the accompanying physical properties are still sufficient for the structural use of such materials in civil engineering practice. It is eminently demonstrated in the paper that the utilisaiton of waste wood materials both in the form of wood powders and wood fibres provides a greener alternative for the waste recycling of industrial debris with respect to the existing waste management options, as well as saves natural resources and the CO2 emissions required to produce the raw materials for the manufacture of these mortars.
Abstract
Gelegentlich wird angenommen, dass Holz einer endlosen Nutzungskaskade zugeführt werden kann. Diese Annahme wird basierend auf Daten von neuen und gebrauchten Spanplatten sowie Altholz der ...Kategorie AI–AIII untersucht. Die Ergebnisse zeigen basierend auf 468 Datensätzen, dass Schadstoffkonzentrationen in Altholz in einem weiten Bereich schwanken. Je nach Probenkollektiv wären 46 % bis 69 % der betrachteten Proben nach geltender AltholzV nicht für eine stoffliche Nutzung geeignet. Es muss davon ausgegangen werden, dass Altholz bereits nach einmaliger Nutzung Schadstoffe in relevanten Konzentrationen enthält und deshalb erst nach Vorliegen der Ergebnisse einer analytischen Überprüfung dem Stoffkreislauf ein weiteres Mal zugeführt werden kann. Eine organoleptische Untersuchung ist hierfür nicht ausreichend.
Abstract
Occasionally, it is assumed that wood can be fed into an endless usage cascade. This assumption is investigated based on data from new and used chipboards, as well as waste wood of category AI–AIII. The results show, based on 468 data sets, that pollutant concentrations in waste wood vary over a wide range. Depending on the sample group, 46 % to 69 % of the samples examined would not be suitable for material use according to the applicable Waste Wood Ordinance. It must be assumed that waste wood already contains pollutants in relevant concentrations after a single use and can therefore only be fed into the material cycle a second time after the results of an analytical examination are available. An organoleptic examination is not sufficient for this purpose.
Highly weathered soils in humid Asia are characterized by low soil fertility and high soil erosion potential. This study evaluates the influences of biochar made from the waste wood of white lead ...trees (Leucaena leucocephala (Lam.) de Wit) on the physicochemical and biological properties of long-term cultivated, acidic Ultisol. This study used three application rates (0%, 2.5%, and 5% (wt/wt)) of the biochar with an incubation time of 105d for all cases. Soils were collected at 21d, 42d, 63d, 84d and 105d during the incubation period to evaluate changes in soil properties over time. A simulated rainfall event (80mmh−1) was performed to estimate soil loss for all treatments at the end of the incubation time. Experimental results indicate that applying biochar improved the physicochemical and biological properties of the highly weathered soils, including significant increases in soil pH from 3.9 to 5.1, cation exchange capacity from 7.41 to 10.8cmol (+) kg−1, base cation percentage from 6.40 to 26.0%, and microbial biomass carbon (MBC) from 835 to 1262mgkg−1. Compared with the control (i.e., no biochar), biochar application decreased bulk density from 1.4 to 1.1Mgm−3, increased Ksat by 1.8 times and increased the mean weight diameter (MWD) of soil aggregates from 2.6cm to 4.0cm. Incorporating biochar into the soil significantly reduced soil loss by 50% and 64% at 2.5% and 5% application rates, respectively, compared with the control. The formation of macroaggregates in the biochar-amended soils is the critical factor to improve soil erosion potential. Based on these results, a 5% application rate of biochar is considered as suitable for highly weathered soil because this application rate efficiently improves soil physiochemical properties and reduces soil loss.
Soil physicochemical properties have been clearly improved and soil erosion potential has been obviously reduced by biochar application in the highly weathered soil. This study interprets alteration of soil aggregate size in terms of soil micromorphology and well explains improved mechanism of soil erosion after biochar application (Fig. 4). Fig. 4 also demonstrated that the biochar could help to bind microaggregates by microbial activity. The redistribution of the proportions of macro- and microaggregates (aggregate sizes obviously increase with biochar application rates) might be the critical factor to reduce soil erosion potential.
Fig. 4. Micrographs of thin sections of soils without and with amendment of biochar: (a) soil aggregates with 2.5% application rate of biochar with plain polarized light (PPL); (b) soil aggregates with 5% application rate of biochar with plain polarized light (PPL); (c) combination of clays and biochar in the 5% application rate of biochar with plain polarized light (PPL); and (d) hyphae between interface of the biochar and soil particle in 5% application rate of biochar-amended soil (PPL). Display omitted
•Biochar addition obviously improves degraded soil physicochemical properties.•Soil erosion rate significantly decreases at least 50% after biochar application.•The increase of macroaggregates is a primary factor to reduce soil losses.
•Investigated physical–chemical properties of commercial, wood-derived biochars.•Tested biochars did not have significant water-leachable PAHs or trace metals.•Degree of carbonization affected ...biochar pH, metal content, and surface area.•SEM image analysis revealed high degrees of microporosity among biochars.•Overall a high variability in biochar physical and chemical properties was observed.
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 (0.1–155.1g/m2) and PAH and heavy metal contents of the solid phase among commercially available biochars was also observed (0.7–83mgkg−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.
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•Gasification for MSW conversion prevents disposal and pollution.•Modified downdraft gasifier achieved cold gas efficiency of 85.6%.•Gasifier design has no throat.•Mass and energy ...balance demonstrated that the entire process was potentially feasible.
Municipal solid waste has become an issue to be addressed with the rapidly growing human population. With implementation of circular economy strategy, this waste can be recovered as an energy resource, assuring a sustainable growth with minimal wasting. However, huge diversity in municipal solid waste often led to complication of processing. Thus, this study proposed a modified downdraft gasifier designed specifically for such heterogeneous feedstock, which includes municipal solid waste and wood waste. The dimensions of the tamarind wood were measured to be 10 cm in length and 6 cm in diameter. The moisture content of the wood was found to be 5.3 %. In this modified downdraft gasifier, the air for the gasification process is fed downward into a rotary grate with an internal air distribution system that is mounted at the reactor's bottom. Separate hot zones were developed as homogeneous and heterogeneous oxidation occurred progressively in the modified gasifier. The suggested gasifier operated at a capacity of 100 kg/h, with air supplied at 150 kg/h and equivalence ratio of 0.3–0.5. Producer gas with the highest calorific value (1250 kcal/Nm3) was produced at the mixed ratio of 50:50 (by mass), with a rate of 250 m3/h. The minor energy and mass imbalance of 1.7 % and 0.2 %, respectively between input and output can be accounted for by environmental heat loss, moisture content and unburned carbon in the ash. The gasifier maintained a consistent syngas flow rate and achieved a cold gas efficiency of 85.6 %. Based on the obtained result, municipal solid waste was successfully transformed into producer gas, with mass and energy balance been adequately maintained.
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