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• A biofilter packaged with perlite, ripe compost, and oak woodchips was used to remove furfural from polluted air. • Totally, the mean values of removal efficiency and elimination capacity of the biofilter were 72 ± 12 % and 2.1 ± 1.5 g m−3 h−1. • The removal efficiency values under neutral and acidic conditions were 80 and 65 %, respectively. Furfural is a toxic compound that is widely used in various industries. Prolonged inhalation exposure to this pollutant, especially at workplaces, can induce detrimental health effects. Therefore it is important to remove it from the environment. The present study aimed to investigate furfural removal from polluted air streams using a biofilter system. In this regard, a 4-section biofilter packed with perlite, ripe compost, and oak woodchips was operated for a 108 day-period under different operating conditions. The effects of pH (natural and acidic), inlet concentration (18.8–81.6 mg m−3), the height of biofilter layers (4 sections), and empty bed residence times (EBRTs) of 120, 70, and 30 s on removal efficiency (RE) of the biofilter were evaluated. All sampling and measurements were performed according to standard methods. The RE values under neutral and acidic conditions were 80 and 65 %, respectively. At furfural inlet concentrations in the ranges of 18.8–21.3, 35.25–42.7, and 78.4–81.6 mg m−3, the RE values were 81, 68, and 57 %, respectively. Also, the RE values at EBRTs of 120, 70, and 30 s were 83, 73, and 61 %, respectively. About half of the total RE was related to the first section of the biofilter, where the number of bacterial (6.2 log 10 CFU g-1) and fungal (5.8 log 10 CFU g-1) were higher than the other sections. Due to the high RE (72 %) and low pressure drop (below 43 Pa m-1) of the biofilter, it can be concluded that biofiltration is a suitable process to remove furfural from the air. [ABSTRACT FROM AUTHOR]

This article describes the experimental setup for estimating the moisture in wood pellets and wood chips by measuring the attenuation of the first longitudinal acoustic resonance mode that is excited in the cylindrical container. The resonance quality is related to losses of sound energy, which are brought about by several phenomena and moisture is one of them. The metrological traceability was carried out by the "loss on drying" method, supported by calibrated balance and a set of reference materials. Using the "loss on drying" method, the amount of moisture in wood pellets was measured in the ranges of 0 %mc to 10 %mc. For acoustic tests in the range of 0 % mc to 56 % mc, reference woodchip material was used. Experimental results show feasibility of concept of traceable acoustic moisture measurement based device. [ABSTRACT FROM AUTHOR]

Abstract Storage is the critical operation within the biomass supply chain to reduce feedstock supply risks and to manage smooth year-around operations of a biorefinery or a bioenergy plant. This paper analyzed the economic and environmental impacts of four different biomass storage systems for woodchips (Outdoor-open, Outdoor-tarped, Indoor, and Silo) and two systems for pellets (Indoor and Silo). Storage cost includes the costs for handling (including ventilation in case of silo storage), infrastructure investment, and dry matter loss (DML) for each system. The estimation of total greenhouse gas (GHG) emissions includes the fugitive emissions from storage piles and emissions due to electricity and fuel consumption for each system. Among four storage systems, the outdoor-tarped ($15.0 ODMT−1, ODMT: Oven Dry Metric Ton) and silo ($5.8 ODMT−1) storage were the least-cost options for woodchips and pellets respectively. However, silo-storage could be the most promising option for storing woodchips ($5.8 ODMT−1) and pellets ($2.3 ODMT−1), if it is used for short-term (two months) and frequently (at least six times) in a year. The total GHG emissions for six-month storage were 2.8–11.8 kgCO 2 e ODMT−1 for woodchips and 8.6–42.0 kgCO 2 e ODMT−1 for pellets. During Outdoor-open storage, the lower heating value of woodchips could drop to 37% due to increased dry-matter loss (DML) and moisture content. The initial moisture content, bulk density, DML, and resource required during handling were the most sensitive parameters influenced the storage performances of both woodchips and pellets. This study has demonstrated that a combination of different storage options along the supply chain could reduce the total biomass storage cost for a biorefinery or power plant. Graphical abstract fx1 Highlights • Large-scale storage options for storing woodchips and pellets were studied. • The outdoor-open storage was the least-cost option for long-term storage of woodchips. • Bin/silo storage was the best option for short-term storage of woodchips and pellets. • The average bin storage cost ranged from 2 to 22 ODMT−1. • All storage systems had low energy use and GHG emissions. [ABSTRACT FROM AUTHOR]

Abstract Wood particle biofilters are being used for remediation of nitrate in watercourses but so far, have received little attention for the possibility of phosphorus (P) treatment. Phosphorus export in many agriculture and urban stressed watercourses however, is dominated by particulate rather than dissolved P and particulate P is potentially treatable by physical filtration. Five low cost, highly permeable media types, including woodchips, sawdust, bark mulch, corn cob chips and peastone, were tested in eight pilot scale biofilters over a six month period for their ability to remove suspended solids (TSS) and particulate P from turbid stream water. The biofilters were operated at high loading rates, with retention times averaging 1.9–4.2 h and achieved TSS removal averaging 85–97%. Excluding a 30 day startup period, seven of the eight biofilters removed an average of 53–64% of stream total P (TP) averaging 65.6 µg/L. The corn cob media provided lower TP removal (1%) because P leached from the media. These filters provided TP removal at hydraulic loading rates that were an order of magnitude higher than when similar media is used for nitrate remediation. These low cost filter media, with capacity for high loading rates, could offer a practical solution for P removal in urban storm water ponds, sewage lagoons and agriculturally impacted water courses. [ABSTRACT FROM AUTHOR]

Highlights • Biofilters can simultaneously control odour and bioaerosol in contaminated air. • There may be differences between biofilter control of fungi and bacteria. • EBRT may not be vital for removal; however, this requires a more extensive study. • Bioaerosol particle size distribution varied between inlet and outlet air. Abstract This study investigated the performance of four pilot-scale biofilters for the removal of bioaerosols from waste airstreams in a materials recovery facility (MRF) based in Leeds, UK. A six-stage Andersen sampler was used to measure the concentrations of four groups of bioaerosols (Aspergillus fumigatus , total fungi, total mesophilic bacteria and Gram negative bacteria) in the airstream before and after passing through the biofilters over a period of 11 months. The biofilters achieved average removal efficiency (RE) of 70% (35 to 97%) for A. fumigatus , 71% (35 to 94%) for total fungi, 68% (47 to 86%) for total mesophilic bacteria and 50% (-4 to 85%) for Gram negative bacteria, provided that the inlet concentration was high (103–105 cfu m−3), which is the case for most waste treatment facilities. The performance was highly variable at low inlet concentration with some cases showing an increase in outlet concentrations, suggesting that biofilters had the potential to be net emitters of bioaerosols. The gas phase residence time did not appear to have any statistically significant impact on bioaerosol removal efficiency. Particle size distribution varied between the inlet and outlet air, with the outlet having a greater proportion of smaller sized particles that represent a greater human health risk as they can penetrate deep into the respiratory system where gaseous exchange occurs. However, the outlet concentrations were low and would further be diluted by wind in full scale applications. In conclusion, this study shows that biofilters designed and operated for odour degradation can also achieve significant bioaerosol control in waste gas. [ABSTRACT FROM AUTHOR]

Moisture content (MC) is the most important quality parameter for energy wood. Unfortunately, checking MC under operational conditions is difficult, because the standard method for MC measurement requires up to 48 h. The bioenergy industry needs alternative methods allowing fast and reliable MC determination, but most of the commercial devices require biomass-specific calibration models. This is an important limitation, particularly in Mediterranean areas, where mixed forest dominate and feedstock loads can include multiple species. In this study a moisture meters based on Magnetic Resonance (MR) was tested for assessing its reliability as an alternative to oven drying. For this purpose, a stress-test was performed at the premises of an energy facility in Southern Italy, using a commercial MR analyzer. Thanks to the non-destructive action on the biomass of MR technology, the MC of 350 samples was measured with both MR and standard gravimetric techniques. Results confirm the validity of the MR analyzer as an alternative to oven drying. Accuracy and precision of the machine are both satisfactory, with over 95% of values within ±2.5% of deviation and a Standard Error of Performance of 1.2%. Furthermore, the analyzer processes over 15 samples per hour, coping with frequent deliveries. [ABSTRACT FROM AUTHOR]

For some environments such as planktonic/aqueous environments, the separation of bacteria cells from eukaryotic cells prior to DNA extraction using filtration is relatively straightforward. However, for woodchips, the bacteria are attached/embedded within the wood matrix, which prevents easy removal of bacterial cells. In this study, a method for the selective extraction of DNA from bacteria inhabiting Eucalyptus spp. woodchips has been developed. The objective was to compare milled and unmilled woodchips processed via three detachment methods, viz., sonication, vortexing and shaking followed by filtration using Teflon filters according to three relevant criteria: DNA yield, DNA purity and quality of DNA. Highest DNA yield was obtained by milling and vortexing for 10 min (77.50 ± 5.17 ng/μl), followed by milling and vortexing for 2 min (61.00 ± 6.56 ng/μl), unmilled and vortexing for 10 min (38.67 ± 5.17 ng/μl) and milled and shaking for 2 h (31.62 ± 5.17 ng/μl). The lowest DNA yield was obtained by using unmilled woodchips and 5 min of sonication treatment (7.00 ± 1.22 ng/μl). There was no significant difference in DNA purity for milled or unmilled woodchips processed via the three detachment methods. Duration of cell detachment treatment did not significantly influence DNA yield and purity. Following optimisation experiments, it was possible to extract bacterial DNA using milled woodchips and 10 minute vortexing devoid of DNA from the host background and other associated eukaryotes and of sufficient quality and quantity for metagenomic analysis. [ABSTRACT FROM AUTHOR]

A new vane shear tester is proposed for the determination of the shear strength in consolidated samples of granular biomass. Measurements are performed using forest woodchips with a normal pressure in the range 5–30 kPa applied at rotation rates of 3–13 rpm. The maximum torque is found to be affected by the normal pressure and time of compression. The rotation speed is not found to have a significant influence on the shear strength. The new apparatus is an efficient tool for determining the mechanical characteristics of granular biomass. The results are in general agreement with those given by the standard Jenike method, but the new technique makes testing easier and faster. Quantitative differences between the results obtained using the two methods are possibly a result of the different modes of load application and the geometry of the shear surface. [ABSTRACT FROM AUTHOR]

Our study investigated the effect of smoking sausages using different types of woodchips—Neem ( Azadirachta indica Valeton.), Copper pod (Cassia siamea Lamk), Earleaf acacia ( Acacia auriculiformis Cunn.), and Eucalyptus ( Eucalyptus camaldulensis Dehn)—compared to commercial Beech woodchips on different qualities of the smoked sausages—pH, water acidity, total acidity, color, sensory properties and shelf life. Moreover, the contents of carcinogenic polycyclic aromatic hydrocarbons (PAHs) of the smoked sausages were evaluated using gas chromatography-mass spectrometry (GC-MS). The results indicated that sausage smoked with Neem woodchips had similar physical qualities, sensory properties and shelf-life (9 weeks) to sausage smoked with Beech woodchips. Total PAHs revealed no significant differences between these two sausages, while the PAH4 levels of sausage smoked with Neem woodchips (1.06 μg/kg) was significantly lower than that of sausage smoked with Beech woodchips (1.54 μg/kg). The sausages smoked with Copper pod woodchips ( L* value 54.1, hardness 13.0 N) and Eucalyptus woodchips ( L* value 50.3, hardness 11.1 N) had lighter color and softer texture than those smoked with Beech woodchips ( L* value 50.8, hardness 13.7 N), respectively, while their total PAH and PAH4 contents were not significantly different. Although the sausage smoked with Earleaf acacia woodchips had the lowest contents of total PAHs, its quality during the 9 weeks of storage was unacceptable due to higher aerobic plate counts which were believed to be related to the low smoke generation temperature of the Earleaf acacia woodchips. Therefore, the overall results suggested that the Neem woodchips could be potentially utilized as a low cost alternative to commercial Beech woodchips for smoking meat products in the meat industry. [ABSTRACT FROM AUTHOR]

This work, performed in the context of Gaya project, focuses on the characterization and modelling of the effect of the pyrolysis heating rate on the steam gasification of char from woodchips. An experimental work was performed based on thermogravimetry and solid characterization of char samples prepared under different conditions. The results showed that gasification apparent reactivity increased with the increase of heating rate. The faster chemical kinetics of char prepared under high heating rate could be related to its higher catalytic inorganic content together with a more reactive carbonaceous structure. The increase of heating rate favours porosity development and the enlargement of pores, which would have a positive effect on gasification reaction rate by enhancing gas diffusion within the solid. The effect of heating rate on char gasification was included in a model previously developed, by correlating the chemical kinetics, particle density and diffusion rate to the char yield, which was selected as a suitable indicator of the heating rate. The new version of the model, considering the variability of heating rate during char formation, was validated through accurate predictions of the experimental results. [ABSTRACT FROM AUTHOR]

The silicon industry is an energy-intensive industry with high energy operating costs and is currently facing new challenges to improve sustainability and become more competitive. Petroleum coke, coal, and charcoal are typically utilized as carbonaceous reductants for silicon production, and the mixture of different carbonaceous materials plays a very important role in the specific power consumption and the exergy efficiency of the process. Of these materials, in particular, charcoal preparation requires large amounts of wood, and continued and extensive deforestation contributes to ecological damage. Thus, it is urgent to study carbonaceous reductants that can be alternatives to charcoal or to find strategies that do not require the application of charcoal in the silicon production process. Exergy efficiency was used as an overall indicator to evaluate the effect of different carbon materials on the process of silicon production in this study. An exergetic efficiency of 0.39 was obtained for silicon produced with a mixture of woodchips and no charcoal. The overall exergy efficiency and the silicon yield exergy indicator results indicated that the addition of woodchips to a mixture of carbonaceous materials improved the performance of the silicon furnace, even if the fixed carbon contribution was lower. There was no change in exergetic efficiency (0.33) for the mixture of petroleum coke and coal as carbonaceous materials with or without charcoal and woodchips. Therefore, a mixture of petroleum coke and coal without charcoal can be used as carbonaceous reductants while maintaining the exergetic efficiency of the process of silicon production. [ABSTRACT FROM AUTHOR]

The environmental legislation and strict enforcement of environmental regulations are the tools effectively used for developing the market of materials for environmental protection technologies. Sustainability criteria shift environmental engineering systems to more sustainable-material-based technologies. For carbon-based medium materials in biofiltration, this trend results in attempts to use biochar for biofiltration purposes. The paper presents the analysis of biochar properties based on the main criteria for biofiltration medium integrating the environmental quality properties of biochar, following the European Biochar Certificate guidelines. Three types of biochar produced from feedstock of highly popular and abundant types of waste are analysed. A multi component approach was applied to summarize the results. The lignocellulosic type of biochar was found to be more competitive for use as a biofiltration medium than the types of biochar with high ash or lignin content. [ABSTRACT FROM AUTHOR]

Landfill leachate contains high concentrations of ammonia and recalcitrant organic compounds, which can interfere with wastewater treatment processes. Hybrid constructed wetlands (CWs), consisting of Vertical Flow (VF) CWs followed by Horizontal Flow (HF) CWs, are low cost technologies for onsite leachate treatment. This study investigated the potential of low-cost adsorbent materials, a natural zeolite mineral (clinoptilolite) and biochar, to enhance leachate treatment in hybrid CWs. Two mesocosm hybrid CWs were set up at a Florida (US) landfill. In the Adsorbent-CW 10% (v /v) of zeolite was added to the VF-CW to enhance nitrification and 13% (v /v) biochar was added to the HF-CW to increase microbial activity and plant growth. A Control-CW contained only gravel. Both systems were planted with cattails (Typha latifolia) and cordgrass (Spartina alterniflora) and operated at varying hydraulic loading rates for ~2 years. A HF-CW containing wood chips (Woodchip-CW) was added downstream of the Adsorbent-CW during the final 6-months of operation to enhance denitrification. Results showed that zeolite addition to the VF-CW significantly increased nitrification rates by 16–93% due to cycles of ammonium adsorption and bioregeneration under intermittent loading conditions. Biochar addition increased removal of organic matter (21–26% to 29–44%) and color (1–18% to 7–49%), and improved wetland plant growth and nitrogen removal due to enhanced plant growth and rhizosphere microbial activity. Addition of the Woodchip-CW reduced nitrate accumulation, resulting in total nitrogen removals of up to 79%. [Display omitted] • Zeolite addition reduced free ammonia inhibition and improved nitrification rate. • Biochar addition enhanced removals of COD, color, organic matter, and heavy metals. • Adsorbent addition improved plant growth for enhanced nitrogen uptake. • Woodchip-CW reduced nitrate accumulation for enhanced nitrogen removal. • Nitrification/denitrification was the main pathway for nitrogen removal. [ABSTRACT FROM AUTHOR]

Mitigation of agricultural nitrogen (N) loss via tile drains using woodchip-based subsurface constructed wetlands seems promising. However, the stochastic nature of drainage discharge and consequent temporal variations in hydraulic loading rates may result in the emission of the greenhouse gases (GHG) nitrous oxide (N 2 O) and methane (CH 4 ) with potentially severe climatic effects that are not yet adequately studied. We investigated the influence of the direction of the convective transport on the net export of GHGs by measuring the two export paths of the gases (emitted and dissolved via the effluent) in six woodchip-based subsurface constructed wetlands with different hydraulic designs (horizontal and vertical up- and downward flow). Emissions ranged from −75.1 to 49.5 μg N 2 O N m −2 h −1 and from −0.28 to 720 mg CH 4 C m −2 h −1 . Dissolved concentrations in the effluent ranged from 0 to 1108 μg N 2 O N L −1 and from 4 to 8452 μg CH 4 C L −1 . Nitrous oxide emissions were negligible; thus, the main export path for N 2 O was as gas dissolved in the effluent. April and December were temporal hotspots for N 2 O production. High CH 4 emissions and high dissolved concentrations were associated with the low hydraulic loading and high temperature occurring during the Danish summer. We found no effect of hydraulic design on the net export of N 2 O, whereas the ratio between CH 4 emissions and net export in the form of dissolved CH 4 via the effluent (the export ratio) was significantly affected. In conclusion, vertical downward flow lowered the export ratio of CH 4 and may be the best hydraulic design, when conditions (i.e. low HLR) facilitate high CH 4 production. [ABSTRACT FROM AUTHOR]

Although basic investigations on wood chip material properties haven been carried out, only few studies deal with transport of wood chips, despite the fact that significant problems are commonly observed when feeding biomass in industrial applications. Within the work presented, basic bulk material properties were measured and experiments carried out with a system consisting of a hopper, agitator and a screw conveyor. The aim of this study was to investigate how three different wood chip grades and two blends of wood chips influence typical design parameters, such as mass flow and driving torque, of a biomass feeding system. The measured basic bulk properties are in good overall agreement with the literature. However, discrepancies were discovered between two standardized methods for determination of the bulk density. The results for the driving torque, mass flow and mass-related energy consumption showed that different grades of wood chips can alter these values considerably. Between two wood chip grades, a twice as high torque was recorded, while a third grade could not be fed due to jamming. One of the major findings of this study is that mixing a rather small amount of a high-fine content grade with the non-feedable grade of wood chips resulted in a blend which inhibited jamming during the screw feeding process. [ABSTRACT FROM AUTHOR]

Nitrate contaminated water can be effectively treated by simultaneous heterotrophic and autotrophic denitrification (HAD). In the present study, woodchips and elemental sulfur were used as co-electron donors for HAD. It was found that ammonium salts could enhance the denitrifying activity of the Thiobacillus bacteria, which utilize the ammonium that is produced by the dissimilatory nitrate reduction to ammonium (DNRA) in the woodchip-sulfur based heterotrophic and autotrophic denitrification (WSHAD) process. The denitrification performance of the WSHAD process (reaction constants range from 0.05485 h −1 to 0.06637 h −1 ) is better than that of sulfur-based autotrophic denitrification (reaction constants range from 0.01029 h −1 to 0.01379 h −1 ), and the optimized ratio of woodchips to sulfur is 1:1 (w/w). No sulfate accumulation is observed in the WSHAD process and the alkalinity generated in the heterotrophic denitrification can compensate for alkalinity consumption by the sulfur-based autotrophic denitrification. The symbiotic relationship between the autotrophic and the heterotrophic denitrification processes play a vital role in the mixotrophic environment. [ABSTRACT FROM AUTHOR]

Mechanical characteristics useful for design and process control were determined for sawdust and woodchips at five levels of moisture content. The density, the modulus of elasticity and relaxation curves were determined using uniaxial compression tester that allowed for measurement of horizontal pressure. The strength properties, the flowability and coefficient of friction against popular construction materials were determined using direct shear tester having 210 mm in diameter shear box. The modulus of elasticity was found to be under strong influence of moisture content of the material. In the case of dry woodchips modulus of elasticity of 0.33 MPa was obtained, while at 50% of moisture content it was of 0.25 MPa. Mean value of angle of internal friction for sawdust was found 27° while that for woodchips was approximately equal to 33°. Effective angle of internal friction ranged from 34° for sawdust to 42° for woodchips. Flow index of sawdust was characteristic for cohesive/easy flowing materials while it was characteristic for cohesive materials in the case of woodchips. Strong negative correlation was observed in relationship between angle of internal friction and moisture content of sawdust. Weak or no correlation of cohesion versus moisture content relationships was observed for both tested materials, while cohesion was found under strong influence by consolidation stress. Friction against construction materials was found higher in the case of woodchips. No influence of consolidation stress on coefficient of friction was noted. With an increase of moisture content above 30% for sawdust and 20% for woodchips decrease in friction coefficient took place. [ABSTRACT FROM AUTHOR]

Fertilizers replenish soil nutrients removed by crops and help in producing high yielding crops, but the overuse of these fertilizers can have a detrimental effect on the receiving waters. There is a need for better management practices and remediation techniques to reduce and potentially eliminate the transport of nutrients from agricultural lands. The objective of this study was to evaluate the removal of orthophosphate using an industrial waste (iron turnings) as well as examine the synergistic effects of using it in conjunction with a woodchip bioreactor known to have a high affinity for nitrate-N removal. A laboratory-scale column reactor was constructed using the iron-based material and woodchips as reactor media. Synergism was displayed as a result of alternating media arrangement with the observation of 25% higher reduction in nitrate-N concentrations, on average, as a result of interaction with woodchips when woodchips were downstream of steel turnings as opposed to upstream. This was also demonstrated in the orthophosphate results, where woodchips reduced orthophosphate concentrations by 8.54% on average when upstream of steel turnings, but yielded a net increase in orthophosphate concentration (23.8% of initial concentration on average) by converting bound phosphate back to orthophosphate when downstream of steel turnings. This led to a final experiment where the steel turnings were placed both upstream and downstream of woodchips. This confirmed earlier findings of enhanced nitrate-N removal by woodchips downstream of iron, while showing that the second iron section downstream of woodchips could once again remove orthophosphate from solution down to non-detectable concentrations. [ABSTRACT FROM AUTHOR]

The baling of freshly harvested wood chips was tested in an Orkel MP2000, a baling machine extensively used in agriculture and industry to densify residues. Wood chips from two different feedstocks: poplar (Populus x euroamericana) and black locust (Robinia pseudoacacia). Baling effected a volume reduction of 43% with respect to the loose bulk density of the piled chips. Each bale has an average mass of 638 kg, and the time consumption to produce one bale was typically 98 s – 122 s. Productivity then varied from 19.8 t h −1 and 21.7 t h −1 of the fresh (green) wood chips. Diesel fuel consumption ranged from 1.4 L t −1 to 1.5 L t −1 of fresh chip weight and represented about 12% of the production cost. The packaging cost is approximately 23 € t −1 of fresh chips equivalent to a bale cost of 15 €. Comminuted wood pressed into bales could provide a valid solution in the use of conventional agricultural and forestry machines. In fact, the handling and transportation of bales can be performed by means of equipment normally used in other agro-forestry activities (front loaders of tractors). In addition, pressed woodchips in packaged bales with waterproof sheets also guarantees a useful storage technique with significant storage surface reduction relative to loose wood chips. [ABSTRACT FROM AUTHOR]

This study was done to investigate the performance of vertical subsurface flow (VSF) wetlands with additional carbon sources in reducing the nitrogen in stormwater from livestock lots. Three experimental lab-scale VSF wetlands packed with woodchips were constructed. The wetlands were operated with number of dry days (NDD) of 2, 4, and 8, respectively, for a duration of 136 d. The average removal efficiencies of total nitrogen (TN) were 26.2, 34.1, and 50.0% at NDD as 2, 4, and 8, respectively. The average nitrogen removal rate based on woodchips volume was 3.6 g N m−3d−1for NDD of 2, 2.1 g N m−3 d−1for NDD of 4, and 1.7 g N m−3 d−1for NDD of 8. Nitrification and denitrification were the major mechanisms of nitrogen reduction in the studied wetlands. The contribution of other pathways to nitrogen removal was small. The removal of total Kjeldahl nitrogen (TKN) and TN was not affected by the influent pH, whereas the removal of TKN was enhanced by the increase in influent alkalinity. Nitrification was promoted by the abundant oxygen supplied during the course of recirculation, whereas denitrification might be suppressed to some degree by the oxygen. [ABSTRACT FROM PUBLISHER]

This study, performed in the context of GAYA project, focuses on the development of a simple predictive model about steam gasification of char from woodchips fast pyrolysis. A semi-empirical model was developed through experiments in a macro thermogravimetric analyzer which owns the peculiar ability of fast heating, as well as to deal with macro-size particles and higher mass loads compared to conventional TGA. The experimental results show that gasification is controlled by chemical kinetics and internal transfer phenomena. During gasification, char particles can be considered as isothermal in a given range of temperatures and particle sizes, more likely for low values. The gasification model was based on the effectiveness factor, which involves the chemical kinetics and diffusion rate. The chemical kinetics were expressed by a classical Arrhenius law, whereas empirical expressions from mathematical fitting of the experimental data were established for the diffusion coefficient and surface function. The diffusion coefficient from this work is suspected to probably include supplementary rate limiting phenomena, apart from steam porous diffusion, such as H 2 inhibition and/or the decrease of temperature within char particles because of the endothermic character of gasification. The model globally predicts with accuracy the gasification rate in typical operating conditions of a fluidized bed reactor. For its simplicity and reliability, this approach can be used for the modelling of char gasification in the conditions of interest. [ABSTRACT FROM AUTHOR]

Pretreatment technologies that can not only reduce the recalcitrance of woody biomass but also achieve a high benefit-cost ratio are desirable for bioenergy production from woody biomass. In this study, an integrated process was proposed and conducted by pretreating woodchips via Shiitake cultivation for improved methane yield during solid-state anaerobic digestion (SS-AD), and simultaneously producing mushrooms as a high-value co-product. Shiitake cultivation using woodchips as the main substrate ingredient obtained mushroom yields comparable to those using a commercial substrate. Enzymatic digestibility and cumulative methane yields (133–160 L kg −1 VS during 62 days of SS-AD) of pretreated substrates (spent mushroom substrate) were at least 1.5 times as high as those of untreated woodchips. Compared to a sole SS-AD process, the integrated Shiitake cultivation/SS-AD process increased methane production and solid waste reduction per kilogram of woodchips by about 1.5 and 8 times, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a thermo-economic analysis of an integrated biogas-fueled solid oxide fuel cell (SOFC) system for electric power generation. Basic plant layout consists of a gasification plant (GP), an SOFC and a retrofitted steam-injected gas turbine (STIG). Different system configurations and simulations are presented and investigated. A parallel analysis for simpler power plants, combining GP , SOFC , and hybrid gas turbine (GT) is carried out to obtain a reference point for thermodynamic results. Thermodynamic analysis shows energetic and exergetic efficiencies for optimized plant above 53% and 43% respectively which are significantly greater than conventional 10 MWe plants fed by biomass. Thermo-economic analysis provides an average cost of electricity for best performing layouts close to 6.4 and 9.4 c€/kWe which is competitive within the market. A sensitivity analysis of the influence of SOFC stack cost on the generation cost is also presented. In order to discuss the investment cost, an economic analysis has been carried out and main parameters such as Net Present Value (NPV), internal rate of return (IRR) and Time of Return of Investment (TIR) are calculated and discussed. [ABSTRACT FROM AUTHOR]

Abstract: Biomass has emerged in the renewable energy area with high potential to contribute to the energy needs in both the industrialized and developing countries. The objective of this study is to evaluate and compare the economic feasibility of three different configurations of a woodchips power plant based on the circulating fluidized-bed (CFB) gasification: (1) a gas engine, (2) a gas turbine, and (3) gas & steam turbines. A comprehensive model of the power plant was developed employing the process simulator, Aspen Plus. The economic feasibility was analyzed in terms of the payback period (PBP), return on investment (ROI), and discount cash flow rate of return (DCFROR). It was proposed that the power plant has an economic benefit for plant sizes of over 150 t/d of dry woodchips in all the three cases. The gas engine was a better choice for the power plant sizes smaller than 200 t/d or 22 MWe, while the gas & steam turbines had the highest benefit at big plant sizes over 200 t/d. A sensitivity analysis was performed for the 150 t/d plant to identify key variables that have a strong impact on DCFROR. The total capital investment (TCI) and plant size had a major influence on DCFROR. [Copyright &y& Elsevier]

The impact of different woodchips (beech, oak, pear, and apple) on the contents of heterocyclic aromatic amines (HAAs) and quality characteristics of smoked bacon was investigated. The results indicated that the contents of total HAAs and non-polar HAAs in beech- and oak-smoked bacon were lower than that in pear- and apple-smoked bacon (P < 0.05). There were no HAAs detectable in control (non-smoking) sample. The smoking process promoted the formation of free amino acids (FAA) in the smoked bacon. The total contents of FAA in beech- and oak-smoked bacon were higher than these in the pear- and apple-smoked bacons (P < 0.05). The beech-smoked bacon had the highest L *-value (P < 0.05), and oak-smoked bacon had the lowest thiobarbituric acid-reactive substance (TBARS) value and carbonyl content (P < 0.05). Additionally, woodchip types had no significant influence on a *-value, b *-value, moisture content, a w , T 20 , T 21 and T 22 (P > 0.05). PCA of the HAA contents and quality characteristics could effectively differentiate that were unsmoked and smoked bacon. Therefore, woodchip types had a great influence on HAA contents and quality of smoked bacon. • Woodchip type had a significant impact on HAA contents and quality in bacon. • Non-polar HAA contents were higher than polar HAA contents in bacon samples. • HAA contents in pear- and apple-smoked bacon were higher than in other samples. • The beech- and oak-smoked bacon had similar HAA content and quality characteristics. [ABSTRACT FROM AUTHOR]

Highlights: [•] Increasing excess air lowered temperature but mixing in the combustor was improved. [•] With the addition of woodchips, combustion shifted to the upper part of the riser. [•] Addition of woodchips increased CO emission, reduced char formation and NO emission. [•] Optimum excess air ratio increased with addition of woodchips to fuel mixture. [Copyright &y& Elsevier]

Abstract: The existing methods of process-based life cycle assessment (LCA) fail to account for the role of ecosystem goods and services derived from natural capital. This study presents an in-depth analysis of resource consumption and atmospheric emissions across a wood-derived bioethanol supply chain. The analysis is based on energy consumption, Industrial Cumulative Exergy Consumption (ICEC), and Ecological Cumulative Exergy Consumption (ECEC) of resources used in the production of one ton of ethanol from woodchips using the near-neutral hemicellulose extraction technology. We found that when compared with fossil-based fuels and corn ethanol, wood-based cellulosic ethanol derived under the near-neutral hemicellulose extraction process demonstrated superior environmental performance. Renewable resources − mostly sunlight and detrital matters – are the dominant contributors to ICEC analysis, whereas non-renewable resources such as crushed stone, crude oil, ores and minerals contribute more to total ECEC. Lime manufacturing, inorganic chemicals production for green liquor preparation, and anthraquinone production have the highest resource consumption. The woodchip washing process and transportation stages consume relatively fewer resources. A performance metric analysis suggests that even though cellulosic ethanol uses a renewable feedstock, its environmental sustainability performance is reduced due to the large consumption of non-renewable resources during the ethanol production stage. [Copyright &y& Elsevier]

Abstract: A three-stage steady state model (TSM) was developed for biomass steam gasification in a dual circulating fluidized-bed (DFB) to calculate the composition of producer gas, carbon conversion, heat recovery, cost efficiency, and heat demand needed for the endothermic gasification reactions. The model was divided into three stages including biomass pyrolysis, char–gas reactions, and gas–phase reaction. At each stage, an empirical equation was estimated from experimental data. It was assumed that both unconverted char and additional fuel were completely combusted at 950°C in the combustor (riser) and the heat required for gasification reactions was provided by the bed material (silica sand). The model was validated with experimental data taken from the literature. The parametric study of the gasification temperature (T) and the steam to fuel ratio (γ) was then carried out to evaluate performance criteria of a 1.8MW DFB gasifier using woodchips as a feedstock for the electric power generation. Effective operating conditions of the DFB gasifier were proposed by means of the contour of the solid circulation ratio, the heat recovery, the additional fuel ratio and the cost efficiency with respect to T and γ. [Copyright &y& Elsevier]

Abstract: The effects of gasification temperature (TG ) and steam to fuel ratio (γ) on product gas composition and yield were experimentally investigated for steam gasification of pine woodchips in a bench-scale circulating fluidized-bed (CFB) gasifier with external heat supplier. To evaluate process performance in a dual circulating fluidized-bed (DFB) with heat carrier (silica sand), a quasi-equilibrium three-stage gasification (qETG) model was developed and validated with experimental data of biomass steam gasification. The model was divided into three stages including biomass pyrolysis, char–gas reactions, and gas-phase reactions. Carbonic and methane formation ratios were considered at the pyrolysis stage under the assumption of spontaneous decomposition. At the second and third stages, char–gas and gas-phase equilibrium reactions were corrected by two empirical equations concerning the steam participation ratio and the non-equilibrium factor, respectively. Using the qETG model, parametric study on TG and γ was performed to predict final gas composition, carbon conversion, char residue, gas yield, lower heating value, additional fuel ratio, solid circulation ratio, heat recovery and H2 to CO molar ratio. Focusing on the solid circulation ratio and H2/CO molar ratio, several effective operating conditions were suggested from the contour of performance criteria. [Copyright &y& Elsevier]

Abstract: Besides the apparent need to reduce greenhouse gas emissions, other important factors contributing to the renewed interest in biofuels are energy security concerns and the need of sustainable transportation fuel. Nearly 30% of the annual CO2 emissions in the U.S. come from the transportation sector and more than half of the fuel is imported. Biofuels appear to be a promising option to reduce carbon dioxide emissions, and the reliance on imported oil concomitantly. The interest on (ligno) cellulosic ethanol is gaining momentum as corn-based ethanol is criticized for using agricultural outputs for fuel production. Among many lignocellulosic feedstocks, woodchips is viewed as one of the most promising feedstocks for producing liquid transportation fuels. The renewable and carbon neutral nature of the feedstocks, similar chemical and physical properties to gasoline, and the low infrastructure cost due to the availability of fuel flex vehicles and transportation networks make (ligno) cellulosic bioethanol an attractive option. An in-depth LCA of woodchips shows that harvesting and woodchips processing stage and transportation to the facility stage emit large amount of environmental pollutants compared to other life cycle stages of ethanol production. Our analysis also found that fossil fuel consumption and respiratory inorganic effects are the two most critical environmental impact categories in woodchips production. We have used Eco-indicator 99 based cradle-to-gate LCA method with a functional unit of 4 m3 of dry hardwood chips production. [Copyright &y& Elsevier]

Abstract: A variety of low-cost carbonaceous solids have been successfully tested in bioreactors designed for nitrate treatment. In many agricultural and wastewater settings, however, such reactors may be practical only if they are maintenance free for a number of years after installation. Although field installations have demonstrated consistent treatment over multi-year timeframes, the ability to accurately quantify slowly declining reaction rates in field settings is problematic because of variations in reactor flow rates, ambient temperatures and influent chemistry. In this study, laboratory column tests were undertaken on four samples of coarse wood particle media (woodchips), two that were fresh and two that had been in continuous operation in subsurface denitrifying bioreactors for periods of 2 and 7 years respectively. Four experimental runs were undertaken at increasing influent NO3-N concentrations of from 3.1 to 48.8mgNL−1. Nitrate mass removal rates remained relatively constant and did not systematically increase in successive runs at higher NO3 concentrations indicating that NO3 was not the rate-limiting substrate at these concentrations. Thus, zero-order reaction kinetics were used to model the attenuation reaction (presumably denitrification). The 7-year-old media had a mean NO3-N removal rate of 9.1mgNL−1 d−1 (6.4gNm−3 mediad−1), which remained within 75% of the rate for the 2-year-old media (12.1mgNL−1 d−1 or 8.5gNm−3 mediad−11) and within 40–59% of the rate for the fresh chips (15.4–23.0mgNL−1 d−1 or 10.8–16.1gNm−3 mediad−1). Results support field experience indicating that woodchips loose about 50% of their reactivity during their first year of operation as soluble organic compounds are leached out, but then relatively stable rates persist for a considerable number of years thereafter. [Copyright &y& Elsevier]

Abstract: Anoxic subsurface flow (SSF) constructed wetlands were evaluated for denitrification using nitrified wastewater. The treatment wetlands utilized a readily available organic woodchip-media packing to create the anoxic conditions. After 2 years in operation, nitrate removal was found to be best described by first-order kinetics. Removal rate constants at 20°C (k 20) were determined to be 1.41–1.30d−1, with temperature coefficients (θ) of 1.10 and 1.17, for planted and unplanted experimental woodchip-media SSF wetlands, respectively. First-order removal rate constants decreased as length of operation increased; however, a longer-term study is needed to establish the steady-state values. The hydraulic conductivity in the planted woodchip-media SSF wetlands, 0.13–0.15m/s, was similar to that measured in an unplanted gravel-media SSF control system. [Copyright &y& Elsevier]

• The smoking decreased the pH and L *-value and increased the a *-value and b *-value. • SP and ST are appropriative for smoked chicken in terms of sensory property. • The total HAAs were higher in smoked samples than in the control. • Smoked samples had higher total aldehyde, but lower alcohol and phenol contents. • S and SA are proper for smoked chicken in terms of minimization of HAAs. This study investigated the effect of different types of smoking materials on the flavor, heterocyclic aromatic amine (HAA) content, and sensory attributes of smoked chicken drumsticks. All smoked samples showed lower pH and L *-value and higher a *-value and b *-value than the control sample (P < 0.05), but no significant differences in water content and water activity (P > 0.05). The samples smoked with sucrose combined with pear-tree woodchips (SP) or green tea leaves (ST) had higher overall acceptability than other samples (P < 0.05). Smoking increased the total HAA content, and the ST sample exhibited the highest total HAA content (P < 0.05). A total of 54 volatile compounds was identified. Overall, SP and ST are suitable for smoked chicken considering the sensory properties, while S and SA are proper for smoked chicken considering the minimization of HAAs, which may provide a theory basis for the production of smoked chicken. [ABSTRACT FROM AUTHOR]

This study investigated the effects of different woodchip types (beech, oak, pear, and apple) on the volatile compounds and sensory characteristics of smoked bacon. The volatile compounds were influenced by woodchip types and the total content of ketones and phenols in pear-smoked bacon were higher than in bacon smoked with other woodchips (P < 0.05). The E-tongue combined with E-nose can effectively distinguish the difference in the flavor of bacon smoked with different woodchip types by the signal intensities. Sensory analysis showed that smoking increased bacon's redness, saltiness, and smoky flavor compared with the control (unsmoked bacon) (P < 0.05) and it had little impact on off-odor (P > 0.05). Correlation analysis showed that the E-nose and E-tongue data were highly correlated with contents of alcohols, aldehydes, and ketones. This study revealed that the different smoked materials greatly influenced the flavor and sensory properties of bacon. [ABSTRACT FROM AUTHOR]

• This paper proposes a capacitive moisture content measurement technique. • A helical capacitive sensor is optimized using the finite element model. • Various factors on the capacitive moisture content measurement are investigated. • Data driven models are developed to predict the moisture content in woodchips. In this paper, a helical capacitive sensor is developed to measure the moisture content (MC) in woodchips. Firstly, based on the orthogonal test method, the structure of the capacitive sensor is optimized to obtain the best possible uniform sensitivity. Then, the effect of the type and random distribution of woodchips on the capacitive MC measurement is investigated. Finally, three different algorithms, including support vector machine, random forest and deep neural network, are employed to establish the data driven models. Experimental results demonstrate that the proposed system is capable of measuring the MC in woodchips with absolute error within ±5%. The generalization capability is verified using the cedarwood with three size ranges, with R2, RMSE and MAE of 0.95, 1.69% and 1.28%, respectively. The absolute error of the predicted MC in cedarwood over the range 24.3% and 25.2% is found to be within ±2% for a range of packing densities. [ABSTRACT FROM AUTHOR]

• Five futures images of woodchip energy use in Finland are created. • The futures images vary based on the type of operator and the role of international regulation. • In the futures images, forest use varies from preservation to the strong promotion of using woodchips as an energy source. • Transition pathways for the current regime of using woodchips as an energy source are identified. Wood is the most widely used renewable energy source in the world. However, there are competing views on how wood should be used in the future. The objective of this study is to examine conceptions related to alternative futures for the use of woodchips as an energy source in Finland. We construct futures images based on two data sources describing the views favouring the use of woodchips: thematic interviews with woodchip users and newspaper articles. The futures images are constructed based on two key themes that emerge from our data. First, the alternatives are imagined for the types of the operators using woodchips in the future, varying between small- and large-scale use. Second, the strong role of regulations, particularly at the European Union level, will be the key driver of the future use of woodchips as an energy source. The results show wide variation in the potential goals of public governance, ranging from regulations designed to strongly support the use of woodchips as an energy source to almost complete conservation of forests. Focusing on the regime level, we identify possible transition pathways illustrating how the use of woodchips could change in the future and discuss possible policy implications. [ABSTRACT FROM AUTHOR]

• Woodchips substrates supplement the carbon source for denitrification. • The COD release rate and sustainability of woodchips are variable. • Woodchips reduced the ORP of CW, enhancing the denitrification of annamox. • The combined substrates realized the simultaneous denitrification and dephosphorization. The lack of carbon source in the denitrification process with low C/N wastewater is the main factor limiting the denitrification efficiency in constructed wetlands (CWs). However, the traditional method of adding liquid carbon source is often costly and facing the risk of secondary pollution. This study attempted to solve this problem by adding woodchips sustained-release carbon sources as part of the substrate, together with the dewatered alum sludge as the main wetland substrate to the baffle subsurface flow constructed wetland (BSFCW). The effects of woodchips on denitrification capacity, effluent COD and nitrogen transfer and transformation were studied. Results showed that the removal rates of ammonia nitrogen (NH 4 +-N), nitrate nitrogen (NO 3 −-N), total nitrogen (TN) and total phosphorus (TP) were 19.0%–75.3%, 63.6%–96.1%, 61.94%–74.4%, 75.0%–98.8%, respectively, when the C/N ratio varies between 0.93 and 1.87. The two-dimensional contour simulation of pollutants concentration in the system indicated that: i) the release rate of COD by woodchips decreased with the time; ii) woodchips reduced the oxidation reduction potential (ORP) of CW system, creating favorable conditions for the denitrification; iii) the closer the woodchips filling position to the inlet, the higher the denitrification efficiency of the system. The combination of dewatered alum sludge and woodchips substrates realized the simultaneous denitrification and dephosphorization of the BSFCW system. This study is of great significance for the treatment of low C/N wastewater containing considerable even high strength P. [ABSTRACT FROM AUTHOR]

• Feedstock type mainly controls the physicochemical characteristics of biochars. • Biochar physical properties were more dependent on particle size than chemical ones. • There was a significant interaction effect between biochar type and particle size. • Post-pyrolyzed size processing is a feasible choice for producing designer biochars. This work aimed to study the changes in the physicochemical properties of biochars induced by post-pyrolyzed particle size processing. Twelve distinct physicochemical attributes of four different particle sized biochars, derived from three different feedstocks, including rice husk, tea wastes and woodchips; were investigated. Amongst all of the investigated characteristics water repellency (η2 = 0.99) and mean pore diameter (η2 = 0.95) were the characteristics most affected by feedstock type and particle size, respectively. The interaction effect between biochar type and particle size was extremely significant (P < 0.001) for surface area and mean pore diameter. While feedstock mainly controlled biochar characteristics, most characteristics were also particle size dependent, where size dependency was more influential on physical than chemical properties. For most properties a significant interaction effect between biochar type and particle size was also detected. [ABSTRACT FROM AUTHOR]

Woodchip denitrifying bioreactors mitigate nitrate loading from agricultural tile effluents. Biochar is considered as an amendment to woodchips. Research findings are contradictory regarding the effect of biochar on nitrate removal. The current study is aimed at investigating the effect of biochar on the removal of nitrate in denitrifying bioreactors. For this purpose, laboratory and field experiments were carried out. In the laboratory, cylindrical up-flow bioreactors were used that were filled with woodchips and oxidized biochar at rates of 0%, 12.5%, 25%, 50% by volume. The removal of nitrate was investigated at two stages: unaged and aged for 16 weeks. The bioreactors were operated at four hydraulic retention times of 2, 4, 8, and 24 h. Additionally, we measured the concentrations of greenhouse gases in the laboratory bioreactors. In the field, nitrate removal over a 6-year period was investigated in two denitrifying bioreactors, one of which amended with 10% fresh biochar. The laboratory experiments showed that, on average, oxidized biochar (OB) amendment reduced nitrate removal by 9% in unaged and 13% in aged bioreactors while the respiration was equal or greater. This led us to conclude that oxidized biochar acted as an electron acceptor. In addition, oxidized biochar increased greenhouse gas concentrations. In the field bioreactors, fresh biochar initially increased nitrate removal. However, biochar became less effective over six years. In the final year, the biochar-amended bioreactor removed less nitrate than the woodchip bioreactor, which was ascribed to the electron-accepting ability of biochar due to aging. In sum, our study showed that biochar's electron acceptability significantly reduced denitrification in denitrifying bioreactors. [ABSTRACT FROM AUTHOR]

• G-SPDR showed better denitrification performance at an appropriate flow rate. • G-SPDR promoted complete denitrification with low NO 2 − accumulation. • Gradient filling improved the NO 3 − removal rate and reduced the bioreactor size. • The distribution pattern of the NO 3 − removal rate was elucidated. • A novel woodchip-packed bioreactor is proposed in this study. Woodchip solid-phase denitrification bioreactors (SPDRs) are widely applied to remove NO 3 − from water. In this study, two SPDRs with different woodchip filling patterns, namely a gradient filling bioreactor (G-SPDR) and a uniform filling bioreactor (U-SPDR), were constructed and their denitrification performances were investigated. Analysis of the NO 3 − removal pathway along the water flow path showed that NO 3 − removal rates could be enhanced using the G-SPDR (35.66–174.55 mg N·L−1·d−1) compared to the U-SPDR (25.17–111.72 mg N·L−1·d−1) at an appropriate flow rate (0.3–1.8 mL·min−1). In addition, the G-SPDR promoted complete denitrification with low NO 2 − accumulation. Chamber model analysis showed that the maximum NO 3 − removal rate was closer to the inlet in the G-SPDR. Furthermore, the optimum reaction height was 25 cm for the G-SPDR and 35 cm for the U-SPDR, implying that gradient filling could reduce the size of the bioreactor. Therefore, gradient filling is a promising and cost-saving method to construct SPDRs for the bioremediation of NO 3 − contaminated water. [ABSTRACT FROM AUTHOR]