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Synergy in the co-processing of lignocellulosic wastes and municipal biowaste (MB) can unlock their potential for biobutanol production. This study assessed the potential for biobutanol production through the co-processing of lignocellulosic waste and MB. Specifically, it compared the co-processing of paper waste with MB to that of garden waste and MB. Ethanol organosolv pretreatment served as a dual-function process for both pretreatment and detoxification purposes. Initial fermentation of hydrolysates from untreated paper waste using Clostridium acetobutylicum produced 0.9 g/L of acetone and ethanol but no detectable butanol. Organosolv pretreatment led to a significant increase in acetone and ethanol production but did not yield butanol. Co-processing paper waste with MB using organosolv pretreatment resulted in the production of 2.8–3.2 g/L butanol, along with increased acetone and ethanol production. Furthermore, co-processing a 1:1 (w/w) mixture of paper waste and MB under mild and severe pretreatment conditions produced 45.5 g and 43.4 g butanol, respectively, compared to 34.8 g and 14.4 g butanol when processing these waste streams separately. The study also explored the positive impact of co-processing garden waste with MB, a distinct lignocellulosic source, enhancing acetone-butanol-ethanol (ABE) yield by 27–40%. These findings highlight the potential of synergistic waste co-processing for achieving a more suitable balance of nutrients to enhance biobutanol and ABE production from biowastes. Additionally, the simultaneous treatment of lignocellulosic waste and municipal biowaste offers a simplified approach to waste processing, contributing to advancements in sustainable biomass utilization and bioenergy production. [Display omitted] • The fermentation of the paper-derived hydrolysates led to acetone but not butanol. • Co-processing with municipal biowaste led to butanol production from paper waste. • The synergy of co-processing and organosolv pretreatment led to higher ABE yields. • The pretreatment positively affected the starch release and cellulose hydrolysis. • Ethanol is a byproduct used as a pretreatment agent to help process circularity. [ABSTRACT FROM AUTHOR]

Regenerated cellulose (RC) was prepared from pineapple crown waste fiber (PCWF) with a yield of about 45 %. The RC was blended with hardwood pulp (HP) to improve the mechanical properties of the paper. The composite paper with improved tensile index from 16.87 ± 0.75 NN mm/g to 28.98 ± 1.2 NN mm/g and burst index from 0.974 ±0.083 kkPaPa mm22/g to 1.827 ±0.153 kkPaPa mm22/g was developed by blending 20 % RC with 80 % HP. It was calculated that the production of one tonne of RC generates about 130 m3 of wastewater and it can be recycled after treatment with electrocoagulation technique. After wastewater treatment, chemical oxygen demand (COD) was reduced 84.8 %, total suspended solid (TSS) by 95.6 %, total dissolved solids (TDS) by 30.4 %, and biochemical oxygen demand (BOD) by 95.8 %. Importantly, the recycling behavior by reusing/recycling the treated wastewater for the regeneration process was investigated and a yield of about 42 % of the RC was observed. [Display omitted] [ABSTRACT FROM AUTHOR]

In the boilers of pulp mills the fuel blends used vary because they are essentially composed of residual forest biomass. Consequently, the physical-chemical properties of the produced ash streams can exhibit high temporal variability, making their proper management and recycling difficult. This study aims to characterize the ash from the incineration of biomass samples used as fuel in order to understand its influence on the properties of the generated ash fluxes. This can anticipate suitable blending procedures that minimize the variability of the ash characteristics. For this purpose, typical biomass samples (eucalyptus bark, treetops and knots, pine treetops, silver wattle, Sydney golden wattle, white poplar, and grey willow) were incinerated (at 550 and 825 °C) and the resulting ashes were characterized. The thermal behavior of the biomass was evaluated by TG/DTA and the generated ash content was determined. The particle size distribution (laser diffraction), morphology (SEM), mineralogy (XRD), and chemical composition (XRF) were other evaluated properties. From the results obtained it is concluded that the ashes cannot be used as raw materials for clinker production. However, they can be used in concrete and mortar formulations, as a cement substitute or as filler. The maximum incorporation amount depends on the type of biomass used, ranging from 54 wt% for pine treetops to 100 wt% for eucalyptus bark. This knowledge is fundamental to understand how to optimize the biomass blends used in industrial combustion systems to obtain ashes with suitable properties to be used as secondary raw materials in building materials formulations. [Display omitted] • Eight types of biomass fuels used in two bubbling fluidized bed boilers were studied. • The ashes generated after biomass incineration at 550 and 825 °C were characterized. • Slagging and fouling are forecast to happen in the combustion systems under study. • The obtained ashes cannot be used as secondary raw material for clinker production. • Maximum ash incorporation in cementitious formulations ranges from 54 to 100 wt%. [ABSTRACT FROM AUTHOR]

Paper mill sludge (PMS) is a residual biomass that is generated at paper mills in large quantities. Currently, PMS is commonly disposed in landfills, which causes environmental issues through chemical leaching and greenhouse gas production. In this research, we are exploring the potential of fast pyrolysis process for converting PMS into useful bio-oil and biochar products. We demonstrate that by subjecting PMS to a combination of acid hydrolysis and torrefaction pre-treatment processes it is possible to alter the physicochemical properties and composition of the feedstock material. Fast pyrolysis of pretreated PMS produced bio-oil with significantly higher selectivity to levoglucosenone and significantly reduced the amount of ketone, aldehyde, and organic acid components. Pretreatment of PMS with combined 4% mass fraction phosphoric acid hydrolysis and 220 °C torrefaction processed prior to fast pyrolysis resulted in a 17 times increase of relative selectivity towards levoglucosenone in bio-oil product along with a reduction of acids, ketones, and aldehydes combined from 21 % to 11 %. Biochar, produced in higher yield, has characteristics that potentially make the solid byproduct ideal for soil amendment agent or sorbent material. This work reveals a promising process system to convert PMS waste into useful bio-based products. More in-depth research is required to gather more data information for assessing the economic and sustainability aspects of the process. [ABSTRACT FROM AUTHOR]

Abstract: To overcome declining markets and low-cost competition, Canadian pulp and paper (P&P) mills are considering the diversification of their product platform. Investing in bioenergy is emerging as a promising way to boost the sector. In this paper, we present a mathematical programming approach to evaluate the profitability of bioenergy investments in the case of a P&P mill, while assessing technical and associated economic risks. The mill, called the integrated forest biorefinery (IFBR), could produce a set of high-value bioproducts from biomass generated in the mill or supplied from outside. P&P activity generates residues, such as black liquor and pulp sludge, which could be used to produce bioenergy. P&P activity should then be well managed, by considering the possibility of temporarily stopping the production of P&P, while assuming the costs associated with the shutdowns. The objective is to develop a mathematically-based approach for investors and stakeholders, within the forest sector that aims to optimise the value creation network of the IFBR and to maximise the profitability of future investments in bioenergy, while optimising the existing P&P activity. [Copyright &y& Elsevier]

The valorization of paper sludge is a high-potential process to develop renewable fuels and chemicals, which can be integrated with pulp and paper mills. Calcium carbonate is the main ash component in sludge, which plays a role in buffering pH and potentially lowering the conversion during enzymatic hydrolysis. Therefore, it is important to investigate the effect of ash on sugar yields and examine pH change to introduce efficient and economical enzymatic hydrolysis of sludge. Carbohydrate conversion was enhanced when the ash was removed by fractionation. On the other hand, the highest sugar recovery was obtained when the sludge contained 20% ash content. The pH change during enzymatic hydrolysis was influenced by ash and explained why sludge-derived hydrolysate showed lower carbohydrate conversion. Therefore, a high shear process with the increased acid amount is suggested to prohibit the negative effect of ash and enhance the accessibility of cellulase to fibers. This study highlights the feasibility of using wet waste streams generated by the paper industry. • Enhanced carbohydrate conversion of sludge containing low ash after fractionation. • Enhanced carbohydrate conversion by lowering the starting pH environment. • Observed pH change during hydrolysis to understand the adverse effect of ash. • Obtained maximum sugar recovery when paper sludge contained 20% ash. • Provided the efficiency of enzymatic hydrolysis depending on the ash content. [ABSTRACT FROM AUTHOR]

Abstract: Upflow anaerobic sludge blanket (UASB) reactor was installed to replace the conventional anaerobic lagoon treating bagasse wash wastewater from agro-based pulp and paper mill, to generate bio-energy and to reduce greenhouse gas emissions. The plant was designed to treat 12MLd−1 of wastewater having two 5ML capacity reactors, 5.75kgCODm−3 d−1 organic loading rate and 20h hydraulic retention time. In the plant 80–85% COD reduction was achieved with biogas production factor of 520Lkg−1 COD reduced. In 11 months 4.4 millionm3 of biogas was generated from bagasse wash wastewater utilizing UASB process. Utilization of the biogas in the Lime Kiln saved 2.14ML of furnace oil in 9 months. Besides significant economic benefits, furnace oil saving reduced 6.4GgCO2 emission from fossil fuel and conversion of the anaerobic lagoon into anaerobic reactor reduced 2.1Gg methane emission which is equal to 43.8Gg of CO2. [Copyright &y& Elsevier]

Ample interest for more efficient utilization of bio-based residues has emerged in the Nordic pulp and paper (P&P) industry, which uses virgin wood as feedstock. Although different bioenergy retrofit technologies for production of liquid, solid, and gaseous bioenergy products have been applied in the existing P&P mills, the number of installations remains small. The lack of profound knowledge of existing bioenergy retrofits hinders the replication and market uptake of potential technologies. This review synthesises the existing knowledge of European installations and identifies the key drivers and barriers for implementation to foster the market uptake of potential technologies. The bioenergy retrofits were reviewed in terms of technical maturity, drivers, barriers and market potential. Based on this evaluation, common drivers and barriers towards wider market uptake were outlined from political, economic, social, technical, environmental, and legal perspective. Technologies already commercially applied include anaerobic fermentation of sludge, bark gasification, tall oil diesel and bioethanol production, whereas lignin extraction, biomethanol production, hydrothermal liquefaction and hydrothermal carbonization are being demonstrated or first applications are under construction. The findings of this review show that a stable flow of residues at P&P mills creates a solid base for retrofitting. New innovative bio-based products would allow widening the companies' product portfolios and creating new businesses. Also, European Union's (EU) legislation drives towards advanced biofuels production. Wider uptake of the retrofitting technologies requires overcoming the barriers related to uncertainty of economic feasibility and unestablished markets for new products rather than technical immaturity. • Bioenergy retrofits can widen the product portfolio of the pulp and paper industry. • Bioenergy retrofits in Europe were comprehensively reviewed for the first time. • Drivers and barriers for the market uptake were assessed from different perspectives. • Retrofits support the REDII targets for advanced biofuels in transport sector. • Utilization of residues for bioenergy products improves mills' resource efficiency. [ABSTRACT FROM AUTHOR]

Abstract: The conversion of ethanol from paper sludge using the separate hydrolysis and fermentation (SHF) process with cellulase and Saccharomyces cerevisiae GIM-2 were investigated in this paper. Optimization strategy based on statistical experimental designs was employed to enhance degree of saccharification by enzymatic hydrolysis of paper sludge. Based on the Plackett–Burman design, hydrolysis time, substrate concentration and cellulase dosage were selected as the most significant variable on the degree of saccharification. Subsequently, the optimum combination of the selected factors was investigated by a Box-Behnken approach. A mathematical model was developed to show the effects of each factor and their combinatorial interactions on the degree of saccharification. The optimal conditions were hydrolysis time 82.7 h, substrate concentration 40.8 g L−1 and cellulase dosage 18.1 FPU g−1 substrate, and a degree of saccharification of 82.1% can be achieved. When hydrolysate was further fermented with S. cerevisiae GIM-2, the conversion rate of sugar to ethanol was 34.2% and the ethanol yield was 190 g kg−1 of dry paper sludge, corresponding to an overall conversion yield of 56.3% of the available carbohydrates on the initial substrate. The results derived from this study indicate that the response surface methodology is a useful tool for optimizing the hydrolysis conditions to converse paper sludge to ethanol. [Copyright &y& Elsevier]

Abstract: The effect of waste paper on biogas yield produced by co-digesting fixed amount of cow dung and water hyacinth in five digesters A–E was studied at room temperature. Waste paper was observed to improve biogas yield in digesters B–E with digester A acting as the control. However, as the amount of waste paper increased the biogas yield was observed to decrease. Kinetic model based on first order kinetic was derived to estimate the maximum, ultimate, biogas yield and also the ultimate methane yield from these biomass mixtures. The maximum biogas yield estimated using this model for digesters B–E were 0.282, 0.262, 0.233, and 0.217 lg−1 VS fed with goodness of fit (R 2) of 0.995, 0.99, 0.889, and 0.925 respectively, which were obtained by fitting the experimental biogas yield (yt ) against (exp(kt)−1)/exp(kt). The ultimate biogas and methane yield at very low batch solid load were extrapolated to be 0.34 and 0.204 lg−1 VS fed respectively. In essence, the addition of waste paper in the co-digestion of cow dung and water hyacinth can be a feasible means of improving biogas yield and also alternative means of recycling waste paper. Furthermore, the kinetic model developed can compliment other models used in anaerobic digestion of agricultural and solid waste. [Copyright &y& Elsevier]

Pulp and paper industry primary sludge being largely composed of lignocellulosic fibres, it could be used as carbon source by bacteria having cellulolytic capability. The aim of this study was to evaluate the use of cellulose contained in this type of sludge for Clostridium thermocellum to produce ethanol, hydrogen and cellulases. In an ATCC 1191 medium containing 5 kg m −3 dry primary sludge from recycled paper mill, batch culture reached stationary phase after 2 days. All of the available cellulose was hydrolysed after 60 h of incubation, with a final pH of 5.83. Metabolites produced after 60 h of fermentation were acetate (8.50 mol m −3 ), ethanol (11.30 mol m −3 ), lactate (8.75 mol m −3 ), formate (0.27 mol m −3 ), hydrogen (11.20 mol m −3 ) and carbon dioxide (18.41 mol m −3 ). Cellulase activity was detected in the supernatant after 36 h, with a maximal activity of 0.25 U cm −3 at 72 h. Pulp and paper primary sludge appeared to be a readily usable substrate for C. thermocellum at this concentration, yielding both potential biofuels (hydrogen and ethanol) as well as active cellulases. [ABSTRACT FROM AUTHOR]

Abstract: The treatment and reutilization of paper sludge (PS) is a worldwide issue. In this study, PS without any pretreatment was used for bioethanol production through simultaneous saccharification and fermentation (SSF) using hyper producer of cellulase and thermotolerant yeast. For saccharification of PS cellulose, cellulase activity was improved from 1.28 × 107 FPU m−3 (wild type) up to 1.52 × 107 FPU m−3 by mutation of Acremonium cellulolyticus C-1 and its carboxymethyl cellulase (CMCase) activity increased 5-fold compared to that of the wild type. In the SSF process, using A. cellulolyticus origin cellulase the highest level of ethanol production was 11.80 and 11.34 kg m−3 from 50 kg m−3 untreated PS in 250 cm3 and 2 dm3 flask scales, respectively. Ethanol yield based on consumed glucose was 80%. This result exhibits a high ethanol production yield from untreated PS, without using a commercial cellulase, nor any pretreatment of PS during SSF process. [Copyright &y& Elsevier]

Abstract In order to make 2nd-generation biofuels more competitive, high solid-matter content has to be reached. To progress towards this target, the mechanism for destructuring lignocellulose fibres in semidilute conditions has to be well understood, as this configuration shows the basic mechanism which limits transfers and efficiency. This study aims to delve deeply into the biophysical and transfer limitations occurring during enzymatic hydrolysis. A specific experimental set-up associating in-situ and ex-situ physical (rheometry, chord length analysis) and biochemical analysis was used to expand the knowledge of hydrolysis of extruded softwood paper pulp over 24 h under different substrate concentrations (1%–3%) and enzyme doses (Accellerase 1500, 5 and 25 FPU/g cellulose). Non-Newtonian behaviour associated with pronounced yield stress stand as the major factors limiting process efficiency. A critical time was deduced from viscosity evolution, and the existence of a unique, dimensionless viscosity-time curve was established, suggesting similar mechanisms for fibre degradation. In addition, chord length distribution allowed for the description of population evolution and was discussed in the light of in-situ viscosity and hydrolysis yield. Physical (viscosity, particle size) and biochemical (substrate) kinetics were modelled (second-order) and coefficients identified. A chronology of the encountered phenomenological limitations demonstrates the necessity of optimising bioprocesses by considering physical parameters. A reference feed rate is proposed in order to reach high solid loading under fed-batch strategy. Highlights • An in- & ex-situ multiscale approach was used to study the paper pulp hydrolysis. • The bio-physical and transfer limitations during hydrolysis were investigated. • A non-Newtonian behaviour was the major factor limiting process efficiency. • A unique dimensionless viscosity-time curve was identified. • A reference feed rate is proposed to reach high solid loading with fed-batch mode. [ABSTRACT FROM AUTHOR]

The aim of this research it is to show how the biogas anaerobic digestion from treatment of recycled pulp and paper wastewater industry (RPPW) can be a renewable energy. Furthermore, a kinetic study of hydrolyzed COD and productions of methane from UASB digester treating RPPW for the continuous test is established. This will allow to reduce the organic matter deposited in landfills and CO 2 emissions and to find viable solutions to minimize the environmental impact of RPPW. This study analyses the biogas products and energy recovery processes from a thermic and electric point of view from the theoretical equations. Thus, this study evaluated the performance of mesophilic methanogenic up-flow sludge blanket reactors (UASB) operating continuously in single-stage (UASB I). The maximum methane yields were 250.9 mLCH 4 /gCOD removed for UASB I, corresponding to 82.7% of the maximum theoretical energy 6.336 kJ/gCOD removed, Methanogenic potential were 4 137 928 m3CH 4 /year and electrical energy potential were 510 703 MWh/year. The kinetic study allowed us a hydrolysis rate kh = 0.04 indicates a correct simulation for the UASB digester treatment system for RPPW with an R = 99.668%. • Anaerobic treatment for RPPW by UASB digester under mesophilic conditions. • Energy generated was 6.336 kJ/gCOD removed and Electrical energy 510 703 MWh/year. • 84% COD and 48% TS were removed at an OLR of 7 g COD/L.d. • At optimal OLR was required to produce average 46 L/d CH 4. • Methane yields were 250.9 mLCH 4 /gCOD removed. [ABSTRACT FROM AUTHOR]

Abstract: Integration of biomass gasification with a pulp and paper mill is a possible route to create more value-added products. This route facilitates, for example, more advanced electricity generation and production of biomass based transportation fuels or chemical feedstock. Each unit operation in such a process affects overall efficiency as well as possibilities for process integration. In this paper, the impact of different dryer types in a biomass gasification combined cycle (BIGCC) has been evaluated in terms of efficiency and economic performance. The BIGCC was sized so that the excess heat would replace the current steam production from bark and oil. The results show that the dryer type can have a significant impact on economic performance and efficiencies. A BIGCC with an integrated belt dryer, utilizing excess heat to heat the drying air from the mill, can result in electrical efficiencies of up to around 40%, while e.g. a steam dryer can reach 36–37%. Choice of oxidant, air or oxygen, in the gasifier affects both capital and operational cost. Air was proven to be the most cost efficient solution for the cases evaluated in this study. The investment of around 100 to 140 million Euros for a BIGCC facility is profitable for most evaluated cases for an annuity factor of 0.1, while the net annual profit is negative for most cases when the annuity factor was increased to 0.2, even when including financial support for renewable electricity. [Copyright &y& Elsevier]

Abstract: Anaerobic digestion of pulp and paper sludge (PPS) and monosodium glutamate waste liquor (MGWL) was studied in completely stirred tank reactors (CSTR) at 37 ± 2 °C. This work focused on the effect of increased organic loading rate (OLR) on the methane production in long-term experiments. For OLR in the range of (1.5–5.0) kg m−3 d−1 based on VS fed, VFA and SCOD concentrations decreased for the first 10 days and then kept stable at about 2.3 kg m−3 and 4.0 kg m−3 respectively until to the critical OLR of 5.0 kg m−3 d−1; and the methane generation rate enhanced to 0.838 m3 m−3 d−1 during this period until to the reactor failure. Additionally, reaction rate constant k and sludge retention time (SRT) are described on the basis of a mass balance in a CSTR followed a first order kinetic equation. In the present study, values for ym and k were obtained as 0.733 m3 kg−1 of removed VS and 0.07 d−1, respectively. The simple model can apply for dimensioning a CSTR digesting of organic wastes from pulp and paper industries, food processing industries, sewage treatment plants or biogas crops. [Copyright &y& Elsevier]

Lignocellulosic biomass is a promising renewable feedstock for the production of bioenergy and platform chemicals; however, its use would not be economically viable without adopting effective transformation technologies. In this work, long-term anaerobic treatment (370 days) of pulp and paper primary sludge (PS) was performed by a thermophilic anaerobic membrane bioreactor (AnMBR) for the first time to investigate the effect of various solid retention times (SRTs) on biogas production and solids reduction ratios. The tested STRs (32–55 days) have shown varying biogas productivity, and it can be concluded that the longer the SRT, the higher is the biogas yield. At the optimum solids retention time of 55 d, an organic loading rate of 2.15 ± 0.10 kg-TSS/L.d, and hydraulic retention time of 5 d, average biogas yield of 106.4 ± 8.5 m3 biogas/tonne TSS added (approximately 72.7 m3 CH 4 /t VS added) was achieved with an average methane content of 56 ± 4% and the solids reduction ratio ranged between 47% and 54.9%. Besides biogas yield, the quality of the permeates, solids reduction, and digestates characteristic/dewaterability changed by changing the SRT. The mixed liquor suspended solids concentrations and solids reduction increased with increasing SRT, while the effluent COD concentration and sludge dewaterability decreased. The Fourier Transform Infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) findings exhibited that the digestate contains more lignin and cellulose than the other substances, while the nitrogen and carbon concentration decreased with increasing SRT. • Long-term anaerobic digestion of pulp and paper primary sludge was performed. • Effect of various solid retention times on biogas yield and solids reduction ratio investigated. • The quality of the permeates and solid reduction ratio changed by changing the solids retention time. • The effluent COD concentration decreased with increasing solid retention time. [ABSTRACT FROM AUTHOR]

This paper presents a MILP (Mixed Integer Linear Programming) model for a continuous packed-bed biomass dryer. The model minimizes total drying costs, including both capital and operational costs, of the dryer. Heated air, which flows through a biomass bed and perforated conveyor, is used as drying gas by the dryer. We define the dryer size with the help of an experimentally-measured characteristic drying curve. The MILP model is tested in a case study where the dryer is assumed to have been installed at a Scandinavian pulp and paper mill. There are three different heat sources available for the heating of drying air: warm water at 60 °C, warm water at 80 °C and backpressure steam at the pressure of 0.4 MPa. The results indicate that, in practice, the use of only low-temperature warm water flows for heating of drying air is the most economic method when their prices are low (below 1 € MWh −1 in the case study). Warm water flows are usually waste heat from pulp and paper mills and their prices are low compared to the price of back-pressure steam (typically from 10 to 15 € MWh −1 ). The use of steam for drying may be reasonable if the price of warm water is for some reason clearly higher than the price of a typical waste-heat stream. The MILP model presented in this work can be used for minimizing drying costs of any material (not only biomass) dried in a continuous packed-bed dryer if the characteristic drying curve of the material is available. [ABSTRACT FROM AUTHOR]

Lignocellulose based processes consist of technology platforms for production of materials and products for developing a bio-based, sustainable economy. Production of sugar streams and ethanol from cellulose is a mature technology, and its deployment results in increased lignin availability. Although lignin is used for low-value applications, its high-value utilization needs to be explored and developed. The aromatic intermediates from lignin can be transformed into high-value products. The unique structural/chemical properties of lignin offer possibilities for valorization, which can be achieved through thermochemical or biological transformation platforms, each route having its pros and cons. Lignin degrading oragnisms hold promise for biovalorization. In this work, different categories of organisms (fungi and bacteria) capable of degrading lignin, possessing unique repertoires of enzymes have been discussed. Under natural niches consortium of organisms decay lignin as a single organism does not possess all the activities. The constraints in biological processing can be addressed by using a combination of processes for lignin depolymerization to aromatic intermediates, followed by their conversion to target products. The recent devised metabolic engineering strategies to tackle these challenges are reviewed. Ultimately, the success of biorefineries will be dictated by the technical feasibility of bioconversions, robustness of engineered organisms, and their ability to produce the desired products in high titers with relatively high purity, scalability, and overall economics. [Display omitted] • Lignin, a byproduct from biorefineries, still underutilized. • High value application entailed depolymerization. • Chemical/catalytic/biological platforms for depolymerization entail challenges. • Biological valorization through ligninolytic organisms and enzymes has potential. • Metabolic engineering to get robust organisms and pure products in high titer. [ABSTRACT FROM AUTHOR]

Abstract: This aim of this study was to optimize the conditions for efficient saccharification of paper sludge (PS) considering PS cellulose concentration, buffer capacity, and cellulase activity from Acremonium cellulolyticus. PS is a cellulosic biomass, the residue of paper making industry, composed of 24.5% cellulose, 10.5% clay, and 65% water. Clay present in PS did not show any inhibitory effect on the saccharification process but influenced the buffer pH. Maleate buffer in the pH range 5.2–5.6 was suitable for the saccharification of PS cellulose. The maximum reducing sugar concentration that could be obtained from 75.6 kg m−3 of PS cellulose was predicted to be 37.8 kg m−3. This was experimentally confirmed to be 38.4 kg m−3 under the optimal saccharification conditions at pH 5.2 (1.06 kmol m−3 Maleate buffer) using Cellulase 20,000 FPU m−3. Almost 100% saccharification yield (SY) was obtained at a low PS cellulose concentration of 15 kg m−3, but this value decreased when the cellulose content increased. When PS was hydrolyzed with commercial cellulase GC220, the SY and glucose content were 54% and 60% of SY, respectively. The corresponding values with Cellulosin T2 were 63% and 75% of SY, respectively. A. cellulolyticus yielded SY and glucose content values almost 10% higher than those obtained with other cellulases. [Copyright &y& Elsevier]

In this paper, lignin-activated carbon xerogels from the black liquor of the paper industry were synthesized by the sol-gel polycondensation of resorcinol and lignin with formaldehyde, NaOH, and water. The sol-gel was prepared at three Lignin/(Lignin+Resorcinol) mass ratios of 0, 13, and 27%. A portion of sol-gel was functionalized with a no-common crosslinking agent, cyanuric chloride (CC) saturated in 1,4-dioxane, to introduce some nitrogen functional groups on the surface. The sol-gels non- and functionalized were dried and activated with H 3 PO 4 at a mass ratio of 1:1 at 450 °C. After the functionalization with the CC and activation process, the superficial nitrogen content percentage increased to 7 wt%, where the most prevalent functionality was N-pyrrole. The sample with a high percentage of nitrogen groups did not show the best electrochemical behavior (112 F g−1 at 0.125 A g−1). However, increasing lignin content up to 27% without functionalization improved the gravimetric capacitance value of 149.5 F −1. These results are mainly attributed to electrostatic effects and the high presence of phosphorus functionalities introduced after the activation process that enhance the surface wettability of the electrodes. Furthermore, the analysis of the variance confirmed that the CC impregnation process did not favor gravimetric capacitance. Lignin can be considered as an excellent substitute for resorcinol partially to produce bio-based activated carbon xerogels and use them as electrodes for supercapacitors and reduce production costs. • Partial substitution of resorcinol for lignin is a good alternative for bio-based xerogels. • The introduction of lignin into carbon xerogel structure did not affect the storage capacity. • Nitrogen can be incorporated into sol-gel using cyanuric chloride as a functionalization agent. [ABSTRACT FROM AUTHOR]

The purpose of the study was to examine the feasibility and capacity of a thermophilic microbial consortium to produce fermentative metabolites from plant polymers. The consortium comprised of cellulolytic anaerobes that were originally enriched from a compost pile using cellulose as the substrate. Fermentative metabolism was examined with monosaccharides, disaccharides, hemicellulose, starch, pectin, chitin, and eight commercial paper samples without further enrichment of the culture to each specific substrate. In general, H 2 , CH 4 , CO 2 , and organic acids were the main metabolites on all substrates but the metabolite profiles varied with the substrate. Similar H 2 yields of 2–3 mol mol −1 substrate at 48 h were obtained with all monosaccharides and disaccharides. The CO 2 yields were higher with disaccharides than with monosaccharides, 4.5 vs 2 mol mol −1 substrate. Metabolite yields were relatively low with glyceraldehyde, glycerol, and arabinose. Paper samples containing high amounts of chemical pulp produced the highest metabolite yields, and biodegradation accounted for ≤74% of total dry weight loss. The fermentative metabolism of the paper samples varied with the pulp composition and the amount of inorganic material. Bacterial community analysis using pyrosequencing analysis of 16S rRNA gene showed a predominance of members of the order Clostridiales, including members of genera Clostridium and Lutispora , which contain known cellulolytic organisms. Most differences among the samples were attributed to small taxonomic groups represented by ≤10% of total sequences. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the prospect of integrating a combined paper&pulp mill with fuel production via biomass gasification was investigated. In the study, three different types of gasifiers (circulating fluidised bed, entrained flow and indirect gasification) and three fuel processes (dimethyl ether, methanol and Fischer-Tropsch wax synthesis) were investigated using computer simulations. The paper reports differences from the stand-alone cases and the integrated cases, using the electricity equivalence efficiency as a measure. Only 6 out of the 18 integrated cases studied displayed a positive result from integration and no obvious fuel selection that stand out as the most beneficial one, however the synthesis of dimethyl ether is, in combination with all gasifiers assessed a rather good choice, with an change in efficiency from integration ranging from −1% to 4%. Dimethyl ether is not the best choice if the electrical equivalence is to be maximised however. In this case the combination of circulating fluidised bed gasification and methanol synthesis should be pursued. The production of Fischer-Tropsch wax should according to the chosen measure not be produced; however there is an added value in the production of a non-oxygenated fuel which has not been taken into account in this particular study. All cases leads to a reduction of 0.4–0.9 kg CO2 per kg of dry biomass used in the process for fuel synthesis and the possibility to export bark is a more significant factor in this respect than which type of fuel is synthesised. [Copyright &y& Elsevier]

Abstract: The hydrolysis of cellulosic fiber used in papermaking by cellulase enzymes was studied as a function of fiber length and temperature. The rate of hydrolysis of the fines fraction increased with temperature but that of the longer fiber was relatively temperature independent. The binding of enzyme to the fiber was proportionately almost three times higher for the fines fraction. Binding of these enzymes to cellulose is known to be inversely temperature dependent, whereas the catalytic step should have a direct dependence on temperature. It is proposed that the two effects offset each other for the longer fiber where there is more free enzyme present as compared to the situation with fines. A similar effect was noted for the hydrolysis of cellulosic paper mill sludge where the rate of hydrolysis of the longer fiber was relatively temperature independent. A practical outcome is that the cost of heating long-fiber sludges to 50°C, the reported optimum temperature for the enzyme, can be avoided. [Copyright &y& Elsevier]

Abstract: The MixAlco™ process biologically converts biomass to carboxylate salts that may be chemically converted to a wide variety of chemicals and fuels. This study looked at the viability of the following substrates: office paper, pineapple residue, Aloe vera rinds, wood molasses, sugar molasses, and glycerol. All agricultural substrates were initially tested to determine their carbohydrate and lignin content because lignin reduces substrate digestibility. Only pineapple residue had a high enough lignin content (18.3%) to necessitate pretreatment. Pineapple residue was treated with excess lime (300gkg−1 Ca(OH)2 on dry biomass, t =1h) and then neutralized with CO2, which reduced the lignin content to 4.89%. All substrates were anaerobically fermented in batch culture with marine microorganisms for 24 days. The acid concentrations (g mixed acid L−1) were Aloe vera (25.5), office paper (24.0), glycerol (22.6), pineapple residue (17.2), wood molasses (19.4) and sugar molasses (18.9). The conversions (g volatile solids digested g−1 volatile solids fed) were Aloe vera (0.59), office paper (0.50), glycerol (0.62), pineapple residue (0.52), wood molasses (0.42) and sugar molasses (0.82). The selectivities (g acetic acid equivalents g−1 VS digested) were Aloe vera (0.64), office paper (0.62), glycerol (0.51), pineapple residue (0.39), wood molasses (0.61) and sugar molasses (0.33). [Copyright &y& Elsevier]

Abstract: To convert cellulosic organics contained in industrial paper sludge into glucose, reaction of pseudo paper sludge composed of cellulose and inorganic compounds (calcium carbonate (CaCO3), talc (Mg3(Si4O10)(OH)2), kaolin (Al2(Si2O5)(OH)4)) under hydrothermal conditions was studied. Significant amounts of glucose (ca. 23%) could be produced from cellulose in the absence of CaCO3 for reaction in water at 523 K and 12 min reaction time. On the other hand, in the presence of CaCO3, most glucose decomposed over all conditions, whereas the addition of talc and kaolin to the mixtures increased the glucose yield to about 30%. For the case of chemical recycle of paper sludge with hydrothermal treatment to obtain d-glucose, it can be concluded that it is preferable to separate the calcium carbonate from the paper sludge before hydrothermal treatment. [Copyright &y& Elsevier]

Abstract: Land application of organic wastes to short rotation woody crops (SRWC) can reduce the environmental impacts associated with waste disposal and enhance the productivity of biomass production systems. Understanding the potential impacts of organic amendments however, requires the examination of changes in soil characteristics and plant productivity. This study was conducted to evaluate the effect of paper sludge and dairy manure on biomass production of shrub willow (Salix dasyclados SV1) and to determine the impacts of these amendments on soil chemical properties. Treatments included urea, dairy manure and paper sludge separately and in combination, and a control. These materials were applied in the summer of 2005 to two fields of SV1 at different stages of growth: An old field with one year old shoots on a 10 year old root system and a young field which was beginning regrowth after being coppiced at the end of its first growing season. Foliar nutrient concentrations and soil chemical properties were analyzed at the end of the second growing season after treatment application to determine plant response to the fertilization regimes and to determine the effects of fertilization on soil characteristics. Fertilization did not increase biomass production in either field. However, application of the N-poor paper sludge did not reduce yield either. In general, fertilization did not influence soil or foliar chemistry, although there were some exceptions. The lack of response observed in this study is probably related to the nutrient status of the site or losses of applied nutrients. [Copyright &y& Elsevier]

Abstract: In this work, we characterized Hesperaloe funifera; pulp and paper obtained by subjecting the plant raw material to soda, soda–anthraquinone, ethanolamine, ethyleneglycol and diethyleneglycol cooking. In addition, the solid fractions extracted by acidifying the cooking liquors, rich in lignin, were used to obtain synthesis and fuel gases. The contents in lignin, α-cellulose, holocellulose, hemicellulose, ethanol–benzene extractives, hot water solubles, 1% NaOH solubles and ash of H. funifera were found to be 7.3%, 40.9%, 76.5%, 35.6%, 4.0%, 13.5%, 29.5% and 5.9%, respectively. The mean fibre length, 4.19 mm, exceeds those for some non-wood materials. Hesperaloe pulp obtained by cooking with 10% NaOH and 1% anthraquinone at 155 °C for 30 min exhibited good values of yield (48.3%), viscosity (737 mL g−1), Kappa number (15.2), tensile index (83.6 Nm g−1), stretch (3.8%), burst index (7.34 kN g−1) and tear index (3.20 mNm2 g−1). Acidification to pH 6 of the liquor resulting from the soda pulping of 500 g of plant raw material provided an amount of 13.90 g of lignin-rich solids pyrolysis of which gave a gas mixture containing 1.13% H2, 31.79% CO and 1.86% CH4 by weight. Gasification of the same sample provided a mixture containing 0.18% H2, 24.50% CO and 17.75% CH4, also by weight. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of the present work was to evaluate the possibility of converting recycled paper sludge (RPS), an industrial residue stream with strong environmental impact, into valuable products. The approach used was based on the enzymatic conversion of major sludge components (cellulose and xylan) and the simultaneous (simultaneous saccharification and fermentation—SSF) or sequential (separate hydrolysis and fermentation—SHF) fermentation of the resulting sugars to ethanol. In the enzymatic hydrolysis step using Celluclast® 1.5L supplemented with Novozym® 188, a degree of saccharification of 100% was achieved. In relation to ethanol production using the yeast Pichia stipitis CBS 5773, SHF and SSF process efficiencies were compared. A slightly higher conversion yield was attained on SHF, corresponding to an ethanol concentration of 19.6gL−1, but 179h were needed. The SSF process was completed after 48h of incubation allowing the production of 18.6gL−1 of ethanol from 178.6gL−1 of dried RPS, corresponding to an overall conversion yield of 51% of the available carbohydrates on the initial substrate. These results demonstrate that the biological conversion of sludge to ethanol is efficient even with no pre-treatment or substrate supplementation. [Copyright &y& Elsevier]

During the process of pulp- and papermaking, large volumes of fibre-rich primary sludge are generated. Anaerobic digestion of primary sludge offers a substantial potential for methane production as an alternative approach to the inefficient energy recoveries by commonly used incineration techniques. However, a systematic study of the importance of upstream process techniques for the methane potential of pulp fibres is lacking. Therefore, biochemical methane potentials were determined at mesophilic conditions for 20 types of fibres processed by a variety of pulping and bleaching techniques and from different raw materials. This included fibres from kraft, sulphite, semi-chemical, chemical thermo-mechanical (CTMP) and thermo-mechanical pulping plants and milled raw wood. The pulping technique was clearly important for the methane potential, with the highest potential achieved for kraft and sulphite fibres (390–400 Nml CH 4 g VS−1). For raw wood and CTMP, hardwood fibres gave substantially more methane than the corresponding softwood fibres (240 compared to 50 Nml CH 4 g VS−1 and 300 compared to 160 Nml CH 4 g VS−1, respectively). Nuclear magnetic resonance characterization of the organic content demonstrated that the relative lignin content of the fibres was an important factor for methane production, and that an observed positive effect of bleaching on the methane potential of softwood CTMP fibres was likely related to a higher degree of deacetylation and improved accessibility of the hemicellulose. In conclusion, fibres from kraft and sulphite pulping are promising substrates for methane production irrespective of raw material or bleaching, as well as fibres from CTMP pulping of hardwood. Image 1 • Kraft and sulphite fibres had high and stable CH 4 potentials (390–400 Nml CH 4 g VS-1). • Shifts in raw material gave large variations in CH 4 potential for CTMP fibres. • Removal of lignin was the most important factor for high CH 4 potential. • Bleaching of CTMP softwood improved CH 4 potential, likely by deacetylation. • Unbleached TMP fibres were inhibitory to AD, while bleaching alleviated this effect. [ABSTRACT FROM AUTHOR]

Abstract: Land-use change (LUC) estimated by economic models has sparked intense international debate. Models estimate how much LUC might be induced under prescribed scenarios and rely on assumptions to generate LUC values. It is critical to test and validate underlying assumptions with empirical evidence. Furthermore, this modeling approach cannot answer if any specific indirect effects are actually caused by biofuel policy. The best way to resolve questions of causation is via scientific methods. Kim and Dale attempt to address the question of if, rather than how much, market-induced land-use change is currently detectable based on the analysis of historic evidence, and in doing so, explore some modeling assumptions behind the drivers of change. Given that there is no accepted approach to estimate the global effects of biofuel policy on land-use change, it is critical to assess the actual effects of policies through careful analysis and interpretation of empirical data. Decision makers need a valid scientific basis for policy decisions on energy choices. [Copyright &y& Elsevier]

Abstract: A conference on current research and educational programs in production of crops for bio-fuel was sponsored and organized by the EARTH University and the University of Florida in November, 2008. The meeting addressed current research on crops for bio-fuel production with discussions of research alternatives for future crop production systems, land use issues, ethics of food vs. fuel production, and carbon sequestration in environmentally sensitive tropical and sub-tropical regions of the Americas. The need and potential for development of graduate and undergraduate curricula and inter-institutional cooperation among educational institutions in the region were also discussed. Delegations from Belize, Brazil, Columbia, Costa Rica, Cuba, Honduras, Panama, The Dominican Republic, and the United States including ministers of Agriculture and Energy attended this meeting. Over a two-day period, four working groups provided a framework to facilitate networking, motivate task oriented creative thinking, and maintain a timely accomplishment of assigned duties in the context of the conference themes. Participants in the conference were assigned to one of four working groups, each following given topics: Agronomy, Environment, Socio-Economics and Education/Extension. It was the consensus of representatives of industry, academic and regulatory community assembled in Costa Rica that significant research, education and socio-economic information is needed to make production of bio-fuel crops sustainable. Agronomic research should include better crop selection based on local conditions, improved production techniques, pest and disease management, and mechanical cultivation and harvesting. Another conclusion was that tailoring of production systems to local soil characteristics and use of bio-fuel by-products to improve nutrient use efficiency and reduction of environmental impact on water quantity and quality is critical to sustainability of bio-fuel crop production. [Copyright &y& Elsevier]

Abstract: Once again Swedish forest industries are supposed to face a new threatening shortage of wood. Therefore, demonstration of new ideas of producing wood for pulp and fuels (heat, ethanol, hydrogen gas, dimethylether, electricity) in the most southern part of Sweden was very welcome. One example of new ideas is that some farmers planted hybrid poplars on abandoned farming land at Sångletorp (33ha), Johannesholm (15ha), Kadesjö (11ha) and Näsbyholm (2ha) in the southernmost part of Sweden in 1991. Some of these plantations were harvested in 2004, but some are still growing. The harvested wood had been used for pulp and fuel. The results of the harvest and of the plantations that are still growing are analysed here from an economic, ecologic and energy point of view. [Copyright &y& Elsevier]

The bark of Pteroceltis tatarinowii is the main raw materials for manufacturing Xuan paper. With the increasing of Xuan paper-making factories, greater demands for bark production will be placed on the new plantations of P. tatarinowii. The objective of this study was designed to investigate the effects of site factors and silvicultural regimes on above-ground biomass production and bark yield of P. tatarinowii plantations. Based on the investigation of 33 plantations of P. tatarinowii, the results indicated that significant differences in above-ground biomass and bark yield among the sites were observed. The ranking of the biomass production and bark yield by rock is slate>phyllite>limestone>sandstone. The average above-ground biomass on the sites with top soil more than 20 cm is 1.45 times of that on the sites with top soil between 10 and 20 cm, and 1.56 times of that on the sites with top soil less than 10 cm. Similar to the above-ground biomass production, the bark yield increased with the increment of top soil depth. Correlation analysis suggested that organic matter, total N, available K and available P were positively related to above-ground biomass production and bark yield, while C/N was negatively. Significant differences in above-ground biomass, bark yield and bark ratio among four planting densities were observed. The highest biomass was achieved at the plantation of 3333 stumps/ha, while the highest bark yield occurred at the plantation of 4200 stumps/ha. In the coppice system of P. tatarinowii plantations, the biomass production and bark yield are significantly affected by stump age, sprout age (rotation length), and the number of sprouts per stump. This investigation indicated that the coppiceability of P. tatarinowii is vigorous and the stumps tend to be long-lived. In term of biomass production and bark yield, 3333–4200 plants/ha as initial planting density, 3-year rotation and 8–12 sprouts per stump are suggested for practical use in establishing the coppice system of P. tatarinowii plantations. [Copyright &y& Elsevier]

Implementation of a lignin-based biorefinery into one of the existing kraft pulp mills calls for increased consumption of resources such as steam (by up to 21.5%), water (by up to 3%), carbon dioxide (by up to 16.2%), and sulphuric acid (by up to 11.3%). To compensate for these extra demands on resources, an advanced process integration method was used to identify steam, water, and chemicals savings options and resource recovery opportunities within the kraft process. Given the importance of the lignin-based biorefinery, an economic viability assessment was carried out toward four scenarios, namely: a reference case relating to a stand-alone kraft pulp mill without a pulp production increase but with/without advanced process integration (scenarios #1 and #2) as well as to an integrated biorefinery with a pulp production increase by 5, 10 and 15% (scenarios #3 and #4). [ABSTRACT FROM AUTHOR]

Pipeline hydro-transport, an economically viable means of delivering large volumes of biomass, can replace conventional modes of transport – road, rail, and river - to improve the economy of pulp and paper mills, as well as bio-based energy facilities. This paper is a review of experimental and theoretical studies conducted by various sectors on the transport of wood and non-wood biomass-water mixtures (slurries) in pipes. The aims were to collect technical challenges, governing mechanical equations, and associated economic issues, as well as to identify the gaps in knowledge in the area. There have been several experiments conducted on pipeline hydro-transport of wood chips over a wide range of pipeline materials, lengths, and diameters. However, pipeline transport of non-wood agricultural residue slurries, as well as the performance of the centrifugal slurry pump handling such mixtures, has recently been investigated in a single lab-scale pipeline facility. Several researchers have proposed empirical correlations to estimate friction loss in wood chip slurries flowing in pipes and also recommended technically and economically optimum pumping velocities. Those correlations, however, are reported to come with noticeable deviations from one another and from experimental measurements. One empirical correlation has been also proposed to predict, with an uncertainty of less than 10%, the longitudinal pressure gradients in pipeline hydro-transport of agricultural residue biomass. All the experimental measurements and empirical correlations based some studies on the economic feasibility of pipelining wood chip-water mixtures. These studies proved the concept of economy of scale to be highly applicable to biomass pipeline systems. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) is a promising process for the upgrading of wet biomass residues. Models of HTC processes, in particular at continuous pilot-scale, are needed to move HTC from lab-scale to industrial scale. This study presents a process model for mild HTC, dewatering and conversion to intermediate energy carriers (bio-pellets and biogas for power and/or heat production) of three wet biomass residue streams: paper sludge, olive pomace and orange peels, based on lab- and pilot-scale experiments. In addition, the process energy efficiency and feedstock utilization of the HTC process is calculated and compared with conventional treatment options for the chosen residues, i.e., direct anaerobic digestion (olive pomace, orange peels) or combustion after conventional dewatering (paper sludge). The process model indicates that the HTC pilot-scale process is much more efficient in terms of feedstock utilization to produce heat and/or power than the reference scenarios. The process energy efficiency of the HTC process (pilot-scale) was calculated to be 26 %, 63 % and 40 % for paper sludge, olive pomace and orange peel feedstocks, respectively. For all feedstocks, both the solid and liquid-generated products are equally important for improving the overall process energy efficiency. This study demonstrates the potential benefits of HTC processes for upgrading wet biomass waste streams based on continuous pilot-scale data. • Hydrothermal carbonization successfully upgraded wet biomass residues for energy. • Hydrothermal carbonization was more efficient for heat/power than reference cases. • Solid and liquid products are both important to improve process energy efficiency. [ABSTRACT FROM AUTHOR]

Abstract: The main objective with this work was to investigate techno-economically the opportunity for integrated gasification-based biomass-to-methanol production in an existing chemical pulp and paper mill. Three different system configurations using the pressurized entrained flow biomass gasification (PEBG) technology were studied, one stand-alone plant, one where the bark boiler in the mill was replaced by a PEBG unit and one with a co-integration of a black liquor gasifier operated in parallel with a PEBG unit. The cases were analysed in terms of overall energy efficiency (calculated as electricity-equivalents) and process economics. The economics was assessed under the current as well as possible future energy market conditions. An economic policy support was found to be necessary to make the methanol production competitive under all market scenarios. In a future energy market, integrating a PEBG unit to replace the bark boiler was the most beneficial case from an economic point of view. In this case the methanol production cost was reduced in the range of 11–18 Euro per MWh compared to the stand-alone case. The overall plant efficiency increased approximately 7%-units compared to the original operation of the mill and the non-integrated stand-alone case. In the case with co-integration of the two parallel gasifiers, an equal increase of the system efficiency was achieved, but the economic benefit was not as apparent. Under similar conditions as the current market and when methanol was sold to replace fossil gasoline, co-integration of the two parallel gasifiers was the best alternative based on received IRR. [Copyright &y& Elsevier]

Abstract: This paper provides analysis of the availability of grain straw resources for centralised industrial usages and suitable areas in China at the prefectural level. China has abundant straw resources for both decentralised and centralised usages. Decentralised usages are inefficient and cannot absorb enough straw. However, centralised usages have technological and economic problems, such as product cost and resource supply, and therefore, a system analysis of the economic available resources and suitable areas are needed. Three main grain crops – rice, wheat, and corn – and three typical centralised usages – paper making, direct combustion power generation, and bioethanol – are investigated in this study. An optimal model is established on the basis of straw resource characteristics and techno-economic characteristics of the usages and used to calculate the distribution of suitable prefectures and the largest supply of resources for each usage. The study focuses on prefectures in 13 provinces with relatively abundant grain straw resources. The suitable areas for paper making are in North China, for direct combustion power generation are in North and Northeast China, for bioethanol are in Northeast China. The largest economic available resources for paper making, direct combustion power generation, and bioethanol are 47.5, 221.4, and 164.4 million tons, respectively. The operation cost and the ratio of straw actually collected from production are selected for conducting a sensitivity analysis. The impacts of other factors, including the geographical environment, local product demand, existing industry, change in total straw production, technical progress and straw from other crops, are discussed. [Copyright &y& Elsevier]

As the regulations related to greenhouse gases (GHG) emissions from fuel become stricter, fundamental changes are being effectuated to achieve the Paris Agreement agenda. Since the aviation sector contributes to 2.5 % of the global CO 2 emission, it is imperative to tackle this conundrum imminently by reducing the CO 2 emission from commercial flights, which are the main contributors to CO 2 emission in the aviation sector. Sustainable aviation fuel (SAF) has garnered tremendous attention in achieving carbon neutrality in the aviation sector. SAF is a suitable alternative since little to no modification of the aircraft is required for SAF usage. There are many challenges when it comes to implementing the use of SAF, including the large-scale production of SAF and the cost associated with the production of SAF. Therefore, this paper aims to provide an overview of various factors related to the global implementation of SAF, considering the latest supporting policy frameworks and from the perspective of feedstock. It examines how existing SAF pathways contribute to large-scale production and explores the role of emerging technologies—from potential feedstocks to the latest advancements. The paper delves into several emerging technologies, including hydrothermal liquefaction, aqueous phase reforming, pyrolysis, and photofermentation, discussing their potential in SAF production and the challenges they present. Furthermore, this paper analyses the life cycle assessment (LCA) and the techno-economic analysis (TEA) of different feedstocks and processes for SAF production. [Display omitted] • Existing policies associated with SAF growth and their limitations are reviewed. • Emerging technologies and challenges of sustainable aviation are explored. • Various feedstocks and ASTM-certified processes for SAF production are discussed. • Techno-economic and environmental aspects related to SAF are summarised. [ABSTRACT FROM AUTHOR]

The pulp and paper industry use biomass residues, such as paper sludge and bark as fuel to provide energy for their plants. However, issues such as high-water content or low heating value limit the amount of energy that can be utilized. Processes to improve heat generation include biomass densification, which facilitates transportation and handling and can increase energy yield. However, the technical feasibility of briquetting is a function of the feedstock and preprocessing. This study introduces a novel approach to briquette production from biomass residues by utilizing wet biomass with water as a natural binder, contrasting with conventional methods that require forced drying and/or the addition of binders. The objective of this research was to investigate the impact of briquetting both unprocessed biomass and post-hydrothermal carbonization. The study focused on manufacturing briquettes derived from different sources, including bark (Balsam fir), paper sludge, and hydrochar of paper sludge. The feedstock was characterized for ash content and higher heating value. Biomass particle size (range), moisture content (range), process temperature (range), process pressure (range), and process residence time (range) were varied in briquetting experiments to determine conditions to produce high-quality briquettes with minimal energy input. Moisture content as high a 50 wt% in feedstock produced technically feasible briquettes, with appropriate physical-mechanical properties (durability, volumetric expansion and apparent density), and energetic potential (calorific value). The addition of heat (pressing temperature of 150 °C) during the pressing process resulted in briquettes with enhanced physical-mechanical, and energetic properties, surpassing those produced at room temperature. Further tests with additional steps in the production process are required to meet commercialization standards in Canada, but the treatments conducted in this study effectively improved the energy potential of biomass for internal industrial energy gains. • Wet briquettes (20 wt% and 50 wt%) production was technically feasible. • Briquettes with added heat (150 °C) exhibited superior properties. • All biomass briquettes exhibited improved energy potential. • Hydrochar briquettes showed superior energy content and durability. [ABSTRACT FROM AUTHOR]

Biochar can be prepared from biomass through pyrolysis in a low-oxygen or anaerobic environment. The characteristics of biochar are influenced by raw materials and the specific preparation process employed. To enhance the efficacy of biochar, various modification methods can be applied. These primarily include chemical modification, physical modification, and biological modification. This paper conducts a literature review covering the period from 2018 to 2023, focusing on biochar preparation, modification methods, and environmental applications. It is a comprehensive overview of the processes involved in preparing biochar, analyzes its characteristics, and explores various modification techniques. Additionally, the paper discusses the diverse and highly efficient application of biochar in environmental remediation, with a particular emphasis on its use in soil, water, and the atmosphere. While biochar holds significant potential for environmental remediation, a thorough understanding of its mechanism in environmental applications is still lacking. Further in-depth studies are required to elucidate the complex roles biochar plays in various environmental contexts. • A summary of the application of modified biochar to soil, water, and atmosphere remediation is presented to show its remediation effect. • Alkali modification of biochar greatly enhances its specific surface area. • Metal salt modification significantly boosts oxygen-containing functional groups in biochar. • Some research directions and future perspectives for modified biochar are highlighted. [ABSTRACT FROM AUTHOR]

Abstract: Caledonian Paper (CaPa) is a major paper mill, located in Ayr, Scotland. For its steam supply, it previously relied on the use of a Circulating Fluidized Bed Combustor (CFBC) of 58 MWth, burning coal, wood bark and wastewater treatment sludge. It currently uses a bubbling fluidized bed combustor (BFBC) of 102 MWth to generate steam at 99 bar, superheated to 465 °C. The boiler is followed by steam turbines and a 15 kg/s steam circuit into the mill. Whereas previously coal, wood bark and wastewater treatment sludge were used as fuel, currently only plantation wood (mainly spruce), demolition wood, wood bark and sludge are used. Since these biosolids contain nitrogen, fuel NO x is formed at the combustion temperature of 850–900 °C. NO x emissions (NO + NO2) vary on average between 300 and 600 mg/Nm3 (dry gas). The current emission standard is 350 mg/Nm3 but will be reduced in the future to a maximum of 233 mg/Nm3 for stand-alone biomass combustors of capacity between 50 and 300 MWth according to the EU LCP standards. NO x abatement is therefore necessary. In the present paper we firstly review the NO x formation mechanisms, proving that for applications of fluidized bed combustion, fuel NO x is the main consideration, and the contribution of thermal NO x to the emissions insignificant. We then assess the deNO x techniques presented in the literature, with an updated review and special focus upon the techniques that are applicable at CaPa. From these techniques, Selective Non-catalytic Reduction (SNCR) using ammonia or urea emerges as the most appropriate NO x abatement solution. Although SNCR deNO x is a selective reduction, the reactions of NO x reduction by NH3 in the presence of oxygen, and the oxidation of NH3 proceed competitively. Both reactions were therefore studied in a lab-scale reactor and the results were transformed into design equations starting from the respective reaction kinetics. An overall deNO x yield can then be predicted for any operating temperature and NH3/NO x ratio. We then present data from large-scale SNCR-experiments at the CFBC of CaPa and compare results with the lab-scale model predictions, leading to recommendations for design and operation. Finally the economic impact is assessed of implementing SNCR-technology when applying an NH3 SNCR or urea SNCR to the CFBC at CaPa. [Copyright &y& Elsevier]

Abstract: Shortage of oil, large variations in exports from Russia of wood to Europe, plenty of abandoned agriculture land, new ideas about a more intensive silviculture; these circumstances are driving forces in Sweden for planting fast-growing poplar and hybrid aspen clones on suitable land. The advantage of such trees is that the wood can be used for both energy (heat, biofuels, electricity), paper and for construction. Poplar clones bred in the USA and Belgium, and older hybrid aspen clones from Sweden, together with new poplar clones collected and selected for Swedish conditions from British Columbia, Canada, were planted during the 1990s in south and central Sweden. The stem diameters and heights of the trees have been measured during the last 10 years and the woody biomass production above ground has been calculated. MAI for all the plantations is 10–31m3 or 3–10ton DM per hectare with the highest annual woody production of 45m3 or 15ton DM per hectare in some years in a very dense plantation in the most southern part of Sweden. All the plantations have been fenced for at least the first ten years. The damage has been caused by stem canker, insects, leaf rust and by moose after removal of the fences. The possibilities for the use of poplar plantations as energy forest and vegetation filters are discussed. [Copyright &y& Elsevier]

It is well known that Trichoderma reesei 's cellulase is deficient in β-glucosidase and cellobiohydrolase II, hampering the synergism of cellulase components and attenuating the cellulose-degrading capability. T. reesei was engineered to enhance its cellobiohydrolase II and cellulase production. However, it was still deficient in β-glucosidase. Therefore, the mixed culture of the recombinant T. reesei and Aspergillus niger was introduced to further improve cellulase production and the performance in enzymatic hydrolysis. It was found to produce the most robust cellulase, whose filter paper activity was 12.17 ± 1.18 FPIU/mL, cellobiohydrolase activity 53.10 ± 2.95 U/mL, endoglucanase activity 716.11 ± 41.16 U/mL, and β-glucosidase activity 1.93 ± 0.28 IU/mL. It had the highest enzymatic hydrolysis yield 89.35%, the lowest cellulase input 25.18 FPIU for 1 g glucose. It just needed 1.96 g SECS (dry material) for producing 1 g glucose. This work is profound and meaningful for lignocellulose-based biorefineries. [ABSTRACT FROM AUTHOR]

This paper presents a systematic literature review on both the risks affecting wood supply security and risk mitigation strategies by quantitative and qualitative data analysis. It describes wood-specific supply chain risks, thereupon resulting impacts and counteracting strategies to ensure supply. Risks, impacts, and strategies are documented as basis for a comparative analysis, discussion of results, challenges and research gaps. Finally, the suitability and the limitations of the chosen methodology and the achieved results are discussed. Scanning wood supply chain risks and supply strategies, most of the reviewed papers focus on wood supply for bioenergy generation and only a few studies investigate wood supply chain risk issues for the sawing, wood panel, pulp and paper industries, or biorefineries. This review differs significantly from other reviews in this field as it considers the entire wood value chain including recent studies on new chemical wood-based products and thus provides a more complete picture of the wood-based bioeconomy. Consequently, it contributes to the literature by providing an overarching investigation of the risks affecting wood supply security and possible side effects of a growing wood-based bioeconomy. It was found that comprehensive value chain analyses considering established wood products, large-volume bioenergy products, as well as established and new chemical wood-based products in the context of wood supply security are missing. Studies that map the entire wood value chain with its multilevel interdependences and integrating cascading use of wood are lacking. • Most studies focus on fuelwood supply chain risks affecting bioenergy generation. • Regulations stimulated studies on bioenergy feedstock supply strategies. • Europe especially shows a research topic in securing bioenergy production. • Supply security analyses in the context of the wood supply chain are rare. • Comprehensive analyses of the entire wood value chain are missing. [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen rich wastewater from monosodium glutamate industry (MSG) and paper-mill wastewater were used in this study as low cost fertilizers for growing corn, a common fuel crop. Detailed characterization of the wastewaters and toxicity testes were conducted to assure the safety of these wastewaters. In a greenhouse pot experiment, effects of these wastewaters on corn growth and biomass yield along with the soil properties were evaluated. MSG-wastewater was applied at three rates i.e., zero, 5 m3 ha−1 and 7.5 m3 ha−1 and paper-mill wastewater was applied at and zero, 3.5 m3 ha−1 and 5 m3 ha−1 in a complete randomized blocks design experiment. Significant increase in the corn biomass yield was observed in all the wastewater treatments compared to the Control. Both these wastewaters did not show any adverse effects on plant. N-use efficiency from the MSG-wastewater was comparable to urea-N application. This study emphasizes on sustainable practices for energy crop production by utilizing wastewaters as fertilizer sources. Hence, we report for the first time that the MSG-wastewater can be used for growing corn as a low cost green practice without adverse affects on the soil properties. [Copyright &y& Elsevier]

Chemi-mechanical pulping (CMP) is a typical high-yield pulping technology to produce various papers and paperboards due to its high yield and high fiber properties. However, it is challenging to further improve its energy efficiency without the scarification of fiber quality. To attack this challenge, herein we study the effects of different hemicellulose pre-extraction on the viscoelasticity of wood cell wall, the energy efficiency, and product properties in chemi-mechanical pulping (CMP) process. Hardwood was first pretreated by NaOH to hydrolyze the benzyl ester bonds that link lignin with hemicellulose, aiming to partially remove hemicellulose and weaken the inter-fiber connections. Then, the hemicellulose-extracted wood underwent refining. The chemical distributions of wood, fiber morphologies, fiber surface fibrillation, energy consumption, and paper properties were extensively studied. The results showed that a 40.8% removal of hemicellulose corresponded to a 90.3% reduction in wood storage modulus (E') and a 68.3% decrease in specific refining energy consumption. Moreover, the weaker connections between microfibrils in the secondary layer, caused by hemicellulose extraction, promoted fiber surface fibrillation during pulp refining. The study elucidates the nonnegligible role of hemicellulose as the linking "bridge" between lignin and cellulose. It also provides a new mechanism in addition to the current classic pulping mechanism including lignin chemical/thermal softening and cellulose swelling in both CMP and chemi-thermomechanical pulp (CTMP). This study offers a feasible and efficient approach to extract hemicellulose from hardwood to reduce the refining energy without scarification of fiber quality, therefore, it holds promise for advanced and greener biorefineries. [Display omitted] • The mechanism of chemical-mechanical pulping about hemicellulose was supplemented. • Removal 40.8% of hemicellulose reduced wet woods' storage modulus by 90.3%. • LC ester bonds hydrolysis weakens connection inter-fibers and inter-microfibrils. • Wood de-hemicellulose optimized fiber separation and fibrillation in refining. [ABSTRACT FROM AUTHOR]