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This study aimed to evaluate the effects of mechanical treatment through twin-screw extrusion for the enhancement of biomethane production. Four lignocellulosic biomasses (i.e., sweetcorn by-products, whole triticale, corn stover and wheat straw) were evaluated, and two different shear stress screw profiles were tested. Chemical composition, particle size reduction, tapped density and cellulose crystallinity were assessed to show the effect of extrusion pretreatment on substrate physico-chemical properties and their biochemical methane production (BMP) capacities. Both mechanical pretreatments allowed an increase in the proportion of particles with a diameter size less than 1 mm (from 3.7% to 72.7%). The most restrictive profile also allowed a significant solubilization of water soluble coumpounds, from 5.5% to 13%. This high-shear extrusion also revealed a reduction in cellulose crystallinity for corn stover (i.e., 8.6% reduction). Sweetcorn by-products revealed the highest BMP values (338–345 NmL/gVS), followed by corn stover (264–286 NmL/gVS), wheat straw (247–270 NmL/gVS) and whole triticale (233–247 NmL/gVS). However, no statistical improvement in maximal BMP production was provided by twin-screw extrusion. Nevertheless, BMP kinetic analysis proved that both extrusion pretreatments were able to increase the specific rate constant (from 13% to 56% for soft extrusion and from 66% to 107% for the high-shear one).

U ovom diplomskom radu izrađeno je idejno rješenje uređaja za pročišćavanje otpadnih voda aglomeracije Rab. Ulazni podaci potrebni za definiranje hidrauličkog i biološkog opterećenja preuzeti su iz Studije izvedivosti za prijavu projekta aglomeracije Rab, za sufinanciranje iz EU fondova. Temeljem ulaznih podataka, a sukladno važećoj zakonskoj regulativi, definiran je potreban stupanj pročišćavanja, što je u konkretnom slučaju prvi (I.) stupanj. Nadalje, izvršeni su hidraulički proračuni kojima su definirane optimalne dimenzije objekata i uređaja koji se nalaze u sklopu postrojenja za pročišćavanje. Dano je oblikovno, funkcionalno i tehničko rješenje linije vode, revizijskih okana, zgrade mehaničkog predtretmana, crpne stanice, aeriranog pjeskolova-mastolova, prethodnog taložnika, zgrade klasirera pijeska, zgrade za obradu mulja i upravne zgrade. Također, izvršena je procjena troškova izgradnje postrojenja do njegovog puštanja u rad. U grafičkim prilozima idejnom rješenju nalaze se nacrti kojima je definiran položaj postrojenja u prostoru te konstruktivno rješenje i dimenzije pojedinih objekata. In this graduate thesis, the conceptual design of the wastewater treatment plant of the Rab agglomeration was made. The input data required for defining the hydraulic and biological load are taken from the Feasibility Study for the application of the Rab agglomeration project, for co-financing from EU funds. Based on the input data, and in accordance with the current legislation, the required degree of purification is defined. Furthermore, hydraulic calculations were carried out that defined the optimal dimensions of the facilities and devices located within the treatment plant. A design, functional and technical solution of the water line, audit shafts, mechanical pretreatment building, pumping station, aerated grit chamber, the primary settling plant, the sand classifier building, the sludge treatment building and the administrative building were given. Also, an estimate of the cost of building the plant until its release into permanent operation was carried out. In the graphic annexes to the conceptual design, there are designs that define the position of the plant in space, and the constructive solution and dimensions of each individual object.

5 Figuras.-- 3 Tablas, The invasive alien seaweed Rugulopteryx okamurae (R.o.) has spread quickly through the Mediterranean Sea causing an unprecedented ecological impact. A solution integrated into a circular economy model is needed in order to curb the negative effects of its presence. Anaerobic digestion (AD) is proposed as a feasible process able to transform biomass into renewable energy. Nevertheless, in order to improve the methane yield and surpass the drawbacks associated with AD processes, this research proposes a thermal pretreatment and a new developed method where the macroalgae is mechanically pretreated with zeolite. Chemical and microstructure characterization of the algal biomass after pretreatments involved scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The highest methane yields of 240 (28) and 250 (20) NLCH4 kg-1 VSadded were obtained with the new mechanical pretreatment and the thermal pretreatment at 120 °C for 45 min without zeolite, achieving a 35 % improvement against the non-pretreated algae. A direct relationship between the crystallinity index of the samples and methane production was observed. The experimental data of methane production versus time were found to be in accordance with both first-order kinetic and Transference Function mathematical models., The authors wish to express their gratitude to the Spanish Ministry of Science and Innovation for providing financial support through the project PID2020-114975RB-100/AEI/10.13039/5011000/11033. Assistant by Dr. Consuelo Cerrillos González on the SEM measurement and analysis is acknowledged. We also thank the CEPSA Foundation, Red Eléctrica de España (REE) and Port Authority of Algeciras Bay (APBA) for their additional financial support for the development of environmental monitoring campaigns for Rugulopteryx okamurae and for obtaining samples of this species used in this work.

Cotton stalks (CS) are lignocellulosic agricultural by-products, a potential source for biogas production, but pretreatment must be considered since hydrolysis is the rate-limiting stage for lignocellulosic biomass substrates. This study investigates the feasibility of mechanical pretreatment of CS to enhance methane production. Batch anaerobic digestion of CS samples with particle sizes ranging from 0.5 to 65 mm was carried out in 1 L eudiometer batch digesters for 48 days at 37°C. Results showed that methane yield was inversely proportional to particle size, and the quality of biogas was good (54.0–55.2% CH4). Significant increases in methane yield were observed with 20.3% and 26% for samples with a particle size of 3 mm and 0.5 mm, respectively, compared to untreated CS. The coefficient of anaerobic energy turnover was relatively low (20.2–25.5%). Reduction of the CS particle size to 3 mm or less is recommended to achieve effective methane conversion and decrease the retention time in an anaerobic digester from 31 to about 25 days. However, to offset the high energy demand required for grinding, further research should be conducted in combining size reduction with chemical and physicochemical pretreatment.

El presente estudio evaluó el comportamiento mecánico y dinámico de cuatro mezclas asfálticas densas en caliente (MD19), tres de estas con sustitución sobre la fracción gruesa (retenida en el tamiz número 4) de agregado reciclado de concreto (ARC) proveniente de las losas de concreto de la ciudad de Bogotá y una mezcla patrón. El agregado natural (AN), ARC y el cemento asfáltico (CA) fueron caracterizados para identificar características físicas y mecánicas, el ARC fue pretratado en la máquina de Los Ángeles para remover parte de la capa de mortero adherido. Se evaluaron las siguientes muestras: 1) MD19 muestra convencional de control; 2) MD19-12.5; 3)MD19-21; 4)MD19-43 muestras con sustitución del 12.5%, 21% y 43% respectivamente del ARC pretratado (ARCP) sobre el AN. Las muestras fueron fabricadas según la metodología de diseño Marshall, adicionalmente se realizó un pretratamiento térmico antes de compactar, a las mezclas con inclusión de ARCP, para posteriormente ser evaluadas en el laboratorio estudiando su comportamiento ante el ahuellamiento, tracción indirecta, modulo resiliente y fatiga. A medida que aumentó el porcentaje de sustitución del ARCP sobre el AN, aumentó también el contenido óptimo de asfalto de las mezclas. Por otro lado, el aumento en la sustitución del ARCP aumentó el porcentaje de vacíos con aire y disminuyó el porcentaje de vacíos llenos de asfalto. La susceptibilidad a la humedad de las mezclas fabricadas aumentó con el aumento de sustitución del ARCP, la rigidez de las mezclas aumentó con la inclusión de ARCP, el comportamiento ante la deformación permanente mejoró para las mezclas MD19-12.5 y MD19-21, el comportamiento a la fatiga de las mezclas mejoró en la medida en que aumentó el porcentaje de sustitución de ARC y el contenido óptimo de asfalto (COA). The present study evaluated the mechanical and dynamic behavior of four hot dense asphalt mixtures (MD19), three of these with substitution on the coarse fraction (retained in sieve number 4) of recycled concrete aggregate (RCA) from concrete slabs. concrete from the city of Bogotá and a standard mix. The natural aggregate (AN), ARC and asphalt cement (CA) were characterized to identify physical and mechanical characteristics, the ARC was pretreated in the Los Angeles machine to remove part of the adhered mortar layer. The following samples were evaluated: 1) MD19 standard control sample; 2) MD19-12.5; 3)MD19-21; 4) MD19-43 samples with substitution of 12.5%, 21% and 43% respectively of the pretreated ARC (ARCP) over the AN. The samples were manufactured according to the Marshall design methodology, additionally a thermal pretreatment was carried out before compacting, to the mixtures including ARCP, to later be evaluated in the laboratory studying their behavior against rutting, indirect traction, resilient modulus and fatigue. . As the substitution percentage of ARCP over AN increased, the optimal asphalt content of the mixtures also increased. On the other hand, the increase in ARCP substitution increased the percentage of voids with air and decreased the percentage of voids filled with asphalt. The susceptibility to moisture of the manufactured mixtures increased with the increase in ARCP substitution, the stiffness of the mixtures increased with the inclusion of ARCP, the behavior against permanent deformation improved for the mixtures MD19-12.5 and MD19-21, the behavior The fatigue of the mixtures improved to the extent that the percentage of ARC substitution and the optimal asphalt content (COA) increased Magíster en Ingeniería Civil Maestría

Polyhydroxyalkanoates (PHAs) are natural polyesters which biodegrade in soils and oceans but have more than double the cost of comparable oil-based polymers. PHA downstreaming from its biomass represents 50% of its overall cost. Here, in an attempt to assist downstreaming, mastication of wet biomasses is tested as a new mechanical continuous biomass pretreatment with potential for industrial upscaling. Downstreaming conditions where both product recovery and purity are low due to the large amount of treated wet biomass (50% water) were targeted with the following process: extraction of 20 g in 100 mL solvent at 30 °C for 2 h, followed by 4.8 h digestion of 20 g in 0.3 M NaOH. Under the studied conditions, NaOH digestion was more effective than solvent extraction in recovering larger PHA amounts, but with less purity. A nearly 50% loss of PHA was seen during digestion after mastication. PHAs downstreamed by digestion with large amounts of impurities started to degrade at lower temperatures, but their melt elasticity was thermally stable at 170 °C. As such, these materials are attractive as fully PHA-compatible processing aids, reinforcing fillers or viscosity modifiers. On the other hand, wet biomass mastication before solvent extraction improves PHA purity and thermal stability as well as the melt rheology, which recovers the viscoelasticity measured with a PHA extracted from a dried biomass., This research was funded by the Portuguese Foundation for Science and Technology (FCT), grant number PTDC/BII-BIO/5626/2020. Additional funding from the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of the IPC (projects UIDB/05256/2020 and UIDP/05256/2020) and contract CEECINST/00156/2018 is also acknowledged.

It is urgent to determine suitable municipal sludge treatment solutions to simultaneously minimize the environmental negative impacts and achieve sustainable energy benefits. In this study, different sludge pretreatment techniques were applied and investigated to enhance the sludge solubility and, subsequently, facilitate the anaerobic biodegradation performance of the mixed sludge under different sludge concentrations and pretreatment techniques. The sludge characteristics before and after pretreatment and batch experiments of anaerobic digestion of sludge samples under different conditions were analyzed and discussed. The results showed that the mechanical pretreatment method, alone and in combination with low-temperature heat treatment, significantly improved the sludge solubility, with the highest solubility at 39.23%. The maximum biomethane yield achieved was 0.43 m3/kg after 10 d of anaerobic digestion of a 3% sludge sample subjected to mechanical and thermal pretreatment prior to anaerobic biodegradation. In comparison, it took more than 28 d to achieve the same biomethane production with the unpretreated sludge sample. Mechanical pretreatment and subsequent heat treatment showed a high ability to dissolve sludge and, subsequently, accelerate anaerobic digestion, thereby providing promising prospects for increasing the treatment capacity of existing and new sludge treatment plants.

In the transition to a climate neutral future, the transportation sector needs to be sustainably decarbonized. Producing advanced fuels (such as biomethane) and bio-based valorised products (such as pyrochar) may offer a solution to significantly reduce greenhouse gas (GHG) emissions associated with energy and agricultural circular economy systems. Biological and thermochemical bioenergy technologies, together with power to gas (P2G) systems can generate green renewable gas, which is essential to reduce the GHG footprint of industry. However, each technology faces challenges with respect to sustainability and conversion efficiency. Here this study identifies an optimal pathway, leading to a sustainable bioenergy system where the carbon released in the fuel is offset by the GHG savings of the circular bio-based system. It provides a state-of-the-art review of individual technologies and proposes a bespoke circular cascading bio-based system with anaerobic digestion as the key platform, integrating electro-fuels via P2G systems and value-added pyrochar via pyrolysis of solid digestate. The mass and energy analysis suggests that a reduction of 11% in digestate mass flow with the production of pyrochar, bio-oil and syngas and an increase of 70% in biomethane production with the utilization of curtailed or constrained electricity can be achieved in the proposed bio-based system, enabling a 70% increase in net energy output as compared with a conventional biomethane system. However, the carbon footprint of the electricity from which the hydrogen is sourced is shown to be a critical parameter in assessing the GHG balance of the bespoke system.

Nowadays, many commercial kits allow the polymerase chain reaction (PCR) detection of Cryptosporidium deoxyribonucleic acid (DNA) in stool samples, the efficiency of which relies on the extraction method used. Mechanical pretreatment of the stools using grinding beads has been reported to greatly improve this extraction step. However, optimization of this key step remains to be carried out. Indeed, many parameters could influence the pretreatment performances, among which the modulation of the speed and duration of the grinding step, in addition to the physicochemical features of the grinding beads, have never been evaluated to date. In this study, eleven commercial mechanical pretreatment matrixes (Lysis matrix tubes®, MP Biomedical, Irvine, CA, USA) composed of beads with different sizes, shapes, and molecular compositions, were evaluated for their performances in improving Cryptosporidium parvum oocyst DNA extraction before amplification by using our routinely used real-time PCR method. As expected, the eleven commercial mechanical pretreatment matrixes showed varying performances depending on the composition, size, and shape. All in all, the best performances were obtained when using the Lysing matrix, including ceramic beads with a median size (diameter of 1.4 mm).

The potential use of elm wood in lignocellulosic industries has been hindered by the Dutch elm disease (DED) pandemics, which have ravaged European and North American elm groves in the last century. However, the selection of DED-resistant cultivars paves the way for their use as feedstock in lignocellulosic biorefineries. Here, the production of cellulose nanofibers from the resistant Ulmus minor clone Ademuz was evaluated for the first time. Both mechanical (PFI refining) and chemical (TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation) pretreatments were assessed prior to microfluidization, observing not only easier fibrillation but also better optical and barrier properties for elm nanopapers compared to eucalyptus ones (used as reference). Furthermore, mechanically pretreated samples showed higher strength for elm nanopapers. Although lower nanofibrillation yields were obtained by mechanical pretreatment, nanofibers showed higher thermal, mechanical and barrier properties, compared to TEMPO-oxidized nanofibers. Furthermore, lignin-containing elm nanofibers presented the most promising characteristics, with slightly lower transparencies.

The potential use of elm wood in lignocellulosic industries has been hindered by the Dutch elm disease (DED) pandemics, which have ravaged European and North American elm groves in the last century. However, the selection of DED-resistant cultivars paves the way for their use as feedstock in lignocellulosic biorefineries. Here, the production of cellulose nanofibers from the resistant Ulmus minor clone Ademuz was evaluated for the first time. Both mechanical (PFI refining) and chemical (TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation) pretreatments were assessed prior to microfluidization, observing not only easier fibrillation but also better optical and barrier properties for elm nanopapers compared to eucalyptus ones (used as reference). Furthermore, mechanically pretreated samples showed higher strength for elm nanopapers. Although lower nanofibrillation yields were obtained by mechanical pretreatment, nanofibers showed higher thermal, mechanical and barrier properties, compared to TEMPO-oxidized nanofibers. Furthermore, lignin-containing elm nanofibers presented the most promising characteristics, with slightly lower transparencies.

International audience; Pre-treatments are often applied in anaerobic digestion in order to improve the performance of the process: increased methane yield and rate. Physical pretreatments are the most commonly used for anaerobic digestion of agricultural waste. The main purpose of this work was to evaluate the effects of different lab-scale mechanical pretreatments on cattle manure. Three mechanical pre-treatments were sequentially applied to cattle manure: shredding, mixing and blending. An original set of analytical procedures was performed before and after mechanical pretreatments, in order to assess physical, chemical and biological properties of the feedstock. Thus, shredding and mixing pre-treatments were not significantly efficient in terms of methane production yield and rate. In contrast, methane production rate increased with blending treatment, and methane yield was slightly improved as well. An increase of soluble chemical oxygen demand (COD) was also reported with blending pretreatment. The reduction of particle size was mainly between 31.5 and 4 mm for all pretreatments and it led to an increase of water retention capacity of the cattle manure. Therefore, mechanical pre-treatments do not only affect the biochemical characteristics of agricultural waste. It also influences its structure and reactivity. In this context, blending pretreatment showed as the most performant pretreatment among the evaluated pretreatments with an increase of 18% on methane rate and a higher COD solubilisation. Graphic Abstract Mechanical pre-treatments are present in almost all biogas plants treating organic waste. However they have been far less investigated than thermal chemical or biological pre-treatments. The objective of this work was to characterize different mechanical effects (shredding mixing and blending) on cow manure. An original characterization procedure has been used including biochemical and physical parameters. Our results show that the methane yield and methane production rate was improved by the pre-treatments the most important effect being blending. Shredding mostly reduced the size of the large particles but its effect on the biochemical characteristics was limited.

As multipurpose, high biomass yielding and resource efficient crop, industrial hemp stands out as a promising source of biomass feedstock for anaerobic digestion (AD). Besides bioenergy cropping systems, the production of renewable biomethane can rely also on the large availability of hemp biomass residues (HBRs), which are generated by different hemp production chains. In the present study, the biochemical methane potential (BMP) of raw and pretreated fibers, stalks, hurds (retted and unretted) as well as of the mix of leaves and inflorescences was assessed through batch anaerobic tests. Untreated hemp fibers showed the highest BMP of 422 ± 20 mL CH4 · g VS-1 among the tested substrates. Retted and unretted hurds reached similar BMP values of 242 ± 13 and 239 ± 10 mL CH4 · g VS-1, respectively, while the mix of leaves and inflorescences showed a low BMP value of 118 ± 8 mL CH4 · g VS-1. Concerning HBRs pretreatments, dilute alkaline pretreatment through a NaOH solution enhanced the BMP of unretted hurds by 15.9%, while a 28.5% increase was obtained with the mix of leaves and inflorescences. Finally, dilute acid pretreatment with a H2SO4 solution showed no significant effect, while mechanical pretreatment through grinding increased the BMP of retted hurds by 15.9%.

Methanization is a technology that involves complex biological reactions and it is the subject of several scientific studies. The paper aims to evaluate the effect of the combined mechanical and ultrasonic pretreatment (CMUP) on the anaerobic digestion (AD) of the household organic waste fraction in Morocco (HOWF), using a continuous stirred tank reactor (CSTR) at mesophilic conditions.This article presents and compares a results obtained by operating two experiments in lab scale reactors with mechanical pretreatment (MP) and with CMUP. The experiment with MP was considered in this study as a control. During the handling period, the effect of CMUP on the AD of HOWF was studied. The process was evaluated in terms of methane production and biodegradability. The stability was maintained within correct parameters throughout the process for each experiment, while the methane yield and biodegradability of the control and CMUP experiments were 382 (mL CH4 g−1VS) (0°C, 1 atm), 72%, and 493 (mL CH4 g−1VS) (0°C, 1 atm), 86 % respectively. This shows clearly that the CMUP enhance the methane production and increase the biodegradability, suggesting that this combination pretreatment improve the hydrolysis and methanogenesis phases of the process.A kinetic study on anaerobic digestion results using the first order model was also used. The mathematical model shows a good fit with the experimental data. Keywords: Anaerobic digestion, HOWF, Mechanical pretreatment, Ultrasonic pretreatment, Methane yield, Biodegradability

Experimental results of leaching tests using waste fractions obtained by mechanical pretreatment of lithium ion batteries (LIB) were reported. Two physical pretreatments were performed at pilot scale in order to recover electrodic powders: the first including crushing, milling, and sieving and the second granulation, and sieving. Recovery yield of electrodic powder was significantly influenced by the type of pretreatment. About 50% of initial LIB wastes was recovered by the first treatment (as electrodic powder with size0.5mm, Sample 1), while only 37% of powder with size1mm (Sample 2) can be recovered by the second treatment. Chemical digestion put in evidence the heterogeneity of recovered powders denoting different amounts of Co, Mn, and Ni. Leaching tests of both powders were performed in order to determine optimized conditions for metal extraction. Solid/liquid ratios and sulfuric acid concentrations were changed according to factorial designs at constant temperature (80°C). Optimized conditions for quantitative extraction (99%) of Co and Li from Sample 1 are 1/10g/mL as solid/liquid ratio and +50% stoichiometric excess of acid (1.1M). Using the same solid/liquid ratio, +100% acid excess (1.2M) is necessary to extract 96% of Co and 86% of Li from Sample 2. Best conditions for leaching of Sample 2 using glucose are +200% acid excess (1.7M) and 0.05M glucose concentration. Optimized conditions found in this work are among the most effective reported in the literature in term of Co extraction and reagent consumption.

Essential oils (EOs) are natural and economically valuable aromatic compounds obtained from a variety of crops and trees, including forest trees, which have different therapeutic and biological activities. This project aims to assess the impact of different residual forest biomass pretreatments on the yield and the properties of EOs, including their antibacterial and antioxidant characteristics. Forest biomass from black spruce (BS, Picea mariana Mill.), balsam fir (BF, Abies balsamea), and jack pine (JP, Pinus banksiana Lamb.) was processed mechanically by (i) shredding, (ii) grinding, (iii) pelletizing, and (iv) bundling. EOs were then extracted by hydro- and steam distillation. The densification into bundles was found to improve EOs yield compared to the other residual forest biomass pretreatments. For example, the yield of bundled BF was improved by 68%, 83%, and 93% compared to shredded, ground, and granulated biomass, respectively. The highest yield was obtained when densification into bundles was combined with extraction through hydrodistillation. As for EOs&rsquo, chemical composition, JP had the highest polyphenol content and consequently the greatest antioxidant activity. EOs derived from BS inhibited the growth of Gram-positive Staphylococcus aureus bacteria and Gram-negative Salmonella typhimurium and Escherichia coli bacteria. The densification of forest biomass into bundles did not affect the antioxidant capacity or the antibacterial activity of EOs, thereby preserving both properties. Thus, the pretreatment of forest biomass residue could have an impact on the volume and the transport costs and therefore improve the bioproducts market and the bioeconomy in Canada.

We determined the potential of three mechanical pulverizers—a continuous ball mill (CBM), an air classifier mill (ACM), and a high-speed mill (HSM)—in the continuous pretreatment of corn stover. The mean diameters of the pulverized biomasses were not significantly different in the three cases, and the glucose yields from the CBM-, ACM-, and HSM-pulverized samples were 29%, 49%, and 44%, respectively. The energy requirements and process capacities for the ACM and HSM were similar. We conclude that the ACM and HSM could be used in the continuous pretreatment of corn stover and would be useful in biofuel production.

Macroalgae have recently attracted attention as a possible feedstock for energy as well as for biogas. Macroalgae have higher productivity than terrestrial plants, and do not compete with crops for arable land but insight is still necessary on the biogas yield for an overall sustainable evaluation. The objective of this study was addressed to evaluate the effect mechanical pre-treatment (MW) on anaerobic digestion (AD) conversion of the brown algae Fucus vesiculosus washed ashore in the Gulf of Riga. The AD were carried out in batch tests at 37 °C, over an incubation time no longer than 21–25 days, in order to evaluate the biological methane potential (BMP). Two mechanical pre-treatment methods were tested including a biomass washing with TAP water and a further manual chopping up to a maximum size of 5 mm. Total solids (TS) and volatile solids (VS) tests were defined according to EPA standards [1] . The batch test-based BMP was further compared with the theoretical biological BMP from Buswell's formula. The results show the BMP is doubling up to 200 l CH 4 /kg TS if any pre-treatments method is applied. The thicker cell walls of the brown marine algae respect other macro algae types and as well respect fresh water macroalgae which inhibit the activity of fermentative bacteria during the hydrolysis process.

In recent years, we have witnessed an increasing interest in the application of mechanochemical methods for processing materials in biomass refining techniques. Grinding and mechanical pretreatment are very popular methods utilized to enhance the reactivity of polymers and plant raw materials; however, the choice of devices and their modes of action is often performed through trial and error. An inadequate choice of equipment often results in inefficient grinding, low reactivity of the product, excess energy expenditure, and significant wear of the equipment. In the present review, modern equipment employing various types of mechanical impacts, which show the highest promise for mechanochemical pretreatment of plant raw materials, is examined and compared—disc mills, attritors and bead mills, ball mills, planetary mills, vibration and vibrocentrifugal mills, roller and centrifugal roller mills, extruders, hammer mills, knife mills, pin mills, disintegrators, and jet mills. The properly chosen type of mechanochemical activation (and equipment) allows an energetically and economically sound enhancement of the reactivity of solid-phase polymers by increasing the effective surface area accessible to reagents, reducing the amount of crystalline regions and the diffusion coefficient, disordering the supramolecular structure of the material, and mechanochemically reacting with the target substances.

The effect of organosolv pretreatment was investigated using a 30 L bench-scale ball mill reactor that was capable of simultaneously performing physical and chemical pretreatment. Various reaction conditions were tried in order to discover the optimal conditions for the minimal cellulose loss and enhanced enzymatic digestibility of Miscanthus × giganteus (MG), with conditions varying from room temperature to 170 °C for reaction temperature, from 30 to 120 min of reaction time, from 30% to 60% ethanol concentration, and a liquid/solid ratio (L/S) of 10–20 under non-catalyst conditions. The pretreatment effects were evaluated by chemical compositional analysis, enzymatic digestibility test and X-ray diffraction of the treated samples. The pretreatment conditions for the highest glucan digestibility yield were determined as 170 °C, reaction time of 90 min, ethanol concentration of 40% and L/S = 10. With these pretreatment conditions, the XMG (xylan + mannan + galactan) fractionation yield and delignification were 84.4% and 53.2%, respectively. The glucan digestibility of treated MG after the aforementioned pretreatment conditions was 86.0% with 15 filter paper units (FPU) of cellulase (Cellic® CTec2) per g-glucan enzyme loading.

This study quantifies the cost of cellulosic sugar production using a fully-mechanical pretreatment process and fuel pellets as a co-product. The pretreatment reduces softwood forest harvest residuals to micron-sized amorphous particles. Energy consumption is minimized using a three-stage milling process. A techno-economic analysis was completed for a milling facility with saccharification and wood pellet manufacture. For the base case, concentrated sugar syrup can be produced for $0.496/kg of sugar. Sensitivity analyses were used to determine cost controlling variables, optimize the sugar cost and found that siting for this technology needs to strongly consider electricity cost and to a lesser extent local feedstock availability. If the sugar produced in this process is used to generate biofuel and is qualified for RIN credits through a life-cycle analysis, the effective cost could be reduced by $0.04–$0.06/kg of sugar. An additional $0.067/kg savings is possible if the biofuel facility is located adjacent or on-site; the finished sugar syrup would not have to be concentrated for transportation. An optimized scenario, including the RIN credit, dilute sugar syrup, and favorable energy costs and consumption, could reduce the cost to $0.34/kg sugar compared to $0.496/kg for the base case.

The aim of this study was to explore the efficiency of a mechano-enzymatic deconstruction of two macroalgae species for sugars and bioethanol production, by using a new enzymatic cocktail (Haliatase) and two types of milling modes (vibro-ball: VBM and centrifugal milling: CM). By increasing the enzymatic concentration from 3.4 to 30 g/L, the total sugars released after 72 h of hydrolysis increased (from 6.7 to 13.1 g/100 g TS and from 7.95 to 10.8 g/100 g TS for the green algae U. lactuca and the red algae G. sesquipedale, respectively). Conversely, total sugars released from G. sesquipedale increased (up to 126% and 129% after VBM and CM, respectively). The best bioethanol yield (6 geth/100 g TS) was reached after 72 h of fermentation of U. lactuca and no increase was obtained after centrifugal milling. The latter led to an enhancement of the ethanol yield of G. sesquipedale (from 2 to 4 g/100 g TS).

The aim of this study was to explore the efficiency of a mechano-enzymatic deconstruction of two macroalgae species for sugars and bioethanol production, by using a new enzymatic cocktail (Haliatase) and two types of milling modes (vibro-ball: VBM and centrifugal milling: CM). By increasing the enzymatic concentration from 3.4 to 30 g/L, the total sugars released after 72 h of hydrolysis increased (from 6.7 to 13.1 g/100 g TS and from 7.95 to 10.8 g/100 g TS for the green algae U. lactuca and the red algae G. sesquipedale, respectively). Conversely, total sugars released from G. sesquipedale increased (up to 126% and 129% after VBM and CM, respectively). The best bioethanol yield (6 g(eth)/100 g TS) was reached after 72 h of fermentation of U. lactuca and no increase was obtained after centrifugal milling. The latter led to an enhancement of the ethanol yield of G. sesquipedale (from 2 to 4 g/100 g TS).

International audience; Mechanical size reduction is considered as a primordial step of current and future lignocellulosic biorefinery. In this sense, it is of high interest to understand who are the biochemical and structural features of the lignocellulosic biomass, which affect the Specific Energy Requirement (SER), and in consequence the cost of mechanical size reduction processes. First, it was shown that the initial moisture content of the lignocellulosic biomass affect the SER and the final particle size distribution. The highest the moisture content gives raise the highest SER. Then, at fixed initial moisture content (≈7% DW), structural and biochemical features of lignocellulosic biomass that can affect the SER were determined. It was noticed that both arabinose/xylose ratio and accessible surface area lead to increasing the SER. On the contrary, the content of cellulose, lignin, crystallinity and p-coumaric acids links were found to have a positive effect on the reduction of the SER.

Cellulose nanofibrils, as a bionanomaterial with many promising properties, have great potential in composite applications. Herein, well-dispersed and uniform-sized cellulose nanofibrils (CNF) was successfully obtained from commercial bleached softwood kraft pulp, with yields of 79.15% via enzyme-assisted hydrolysis and a subsequent homogenization process. Field emission scanning electron microscope (FE-SEM) confirmed the fiber morphology. Water retention value (WRV) was increased from 107.32% of original pulp to 1383.92% of the resulting CNFs, while crystallinity had no significant changes. Fourier transform infrared (FTIR) spectroscopy indicated the addition of enzyme resulted in the removal of hemicelluloses and lignin. CNFs subjected to enzymatic treatment and homogenization had less entangled network, larger aspect ratio and higher transmittance than those from pure mechanical treatment. They exhibited well-dispersed in aqueous solution and uniform-sized in morphology. These advantages revealed enzyme-assisted process had a remarkable effect on the production of CNFs and made CNFs attractive for nanotechnology and nanomaterial.

Animal manure digestion is associated with limited methane production, due to the high content in fibers, which are hardly degradable lignocellulosic compounds. In this study, different mechanical and thermal alkaline pretreatment methods were applied to partially degradable fibers, separated from the effluent stream of biogas reactors. Batch and continuous experiments were conducted to evaluate the efficiency of these pretreatments. In batch experiments, the mechanical pretreatment improved the degradability up to 45%. Even higher efficiency was shown by applying thermal alkaline pretreatments, enhancing fibers degradability by more than 4-fold. In continuous experiments, the thermal alkaline pretreatment, using 6% NaOH at 55°C was proven to be the most efficient pretreatment method as the methane production was increased by 26%. The findings demonstrated that the methane production of the biogas plants can be increased by further exploiting the fraction of the digested manure fibers which are discarded in the post-storage tank.

An innovative process was optimized to recover Co from portable Lithium Ion Batteries (LIB). Pilot scale physical pretreatment was performed to recover electrodic powder from LIB. Co was extracted from electrodic powder by a hydrometallurgical process including the following main stages: leaching (by acid reducing conditions), primary purification (by precipitation of metal impurities), solvent extraction with D2EPHA (for removal of metal impurities), solvent extraction with Cyanex 272 (for separation of cobalt from nickel), cobalt recovery (by precipitation of cobalt carbonate). Tests were separately performed to identify the optimal operating conditions for precipitation (pH 3.8 or 4.8), solvent extraction with D2EHPA (pH 3.8; Mn/D2EHPA = 4; 10% TBP; two sequential extractive steps) and solvent extraction with Cyanex 272 (pH 3.8; Cyanex/Cobalt = 4, 10% TBP, one extractive step). The sequence of optimized process stages was finally performed to obtain cobalt carbonate. Products with different degree of purity were obtained depending on the performed purification steps (precipitation with or without solvent extraction). 95% purity was achieved by implementation of the process including the solvent extraction stages with D2EHPA and Cyanex 272 and final washing for sodium removal.

Extrusion pretreatment of lignocellulosic biomasses is a physical continuous pretreatment method for subsequent fermentative ethanol production. Twin-screw elements (conveying, kneading and reverse) have different effects on enzymatic digestibility according to their geometries and functions. The first study evaluated the effects of individual functional screw elements on enzymatic digestibility and found that extrusion enhanced enzymatic digestibility under all tested condition. Reverse and kneading screw elements however resulted in lignin re-distribution over the cellulose fibres, blocked pores (shown via SEM) and resulted in less digestible biomass, compared to conveying screw elements, only. Lignin removal via NaOH reversed this effect and the highest digestibility was found for biomass extruded in the presence of reverse screw elements (the most severe conditions tested in this study). Based on these finding a process was developed for separating xylose from lignocellulosic biomass (steam-exploded corncobs) in a co-rotating twin-screw extruder, through water addition and solid-liquid separation. Eight screw configuration profiles were evaluated to define the best performance on xylose recovery. Subsequently, operating conditions (barrel temperature, screw speed and water flow rate) were examined with respect to xylose recovery and specific mechanical energy consumption. It was found that liquid/solid separation highly depended on the position and spacing of reverse screw elements. In addition, more xylose was recovered as the screw speed decreased and water flow rate and barrel temperature increased. Furthermore, operating conditions influenced the specific mechanical energy consumption of the motor drive. The extruder was then used to produces differently treaded biomass samples, and a response surface method (RSM)-based model using IV-optimal design was used to study the combined effects of various enzymatic hydrolysis process variables (enzyme loading, surfactant addition, and hydrolysis time) with two differently extruded corncobs (7% xylose removal, 80% xylose removal) on glucose conversion. The results showed that the extrusion process led to an increase in cellulose crystallinity, while structural changes could also be observed via SEM. A quadratic polynomial model was developed for predicting the glucose conversion and the fitted model provided an adequate approximation of the true response as verified by the analysis of variance (ANOVA).

Die zunehmende Nutzung von Energiepflanzen als Haupteinsatzstoff und der damit verbundende Flächenverbrauch ist der zentrale Kritikpunkt der Bevölkerung an der Biogasproduktion. Obwohl erhebliche energetische Potentiale an Abfällen und Reststoffen vorhanden sind, konnte sich die Verwertung dieser Materialien im Biogasprozess bis heute nicht flächendeckend etablieren. Wesentliche Hemmnisse sind hierbei die stark variierende Zusammensetzung dieser Stoffe und deren Substrateigenschaften. In der Regel beinhalten die Reststoffe einen hohen Faseranteil, der die vorhandene Verfahrenstechnik vor große Herausforderungen stellt. Daher war das Ziel dieser Arbeit, die Eignung und Verwertbarkeit des rohfasereichen Substrates Pferdemist als Beispielsubstrat zur Biogaserzeugung in kontinuierlich betriebenen landwirtschaftlichen Biogasanlagen zu untersuchen. Um dieses Ziel zu erreichen, wurde die vorliegende Arbeit in drei Abschnitte gegliedert: 1. Untersuchung der Zusammensetzung und Verwertbarkeit von Pferdemist mit verschiedenen Einstreumaterialien und Bestimmung der spezifischen Methanerträge unter Berücksichtigung des Alterungsprozesses des Pferdemistes; 2. Ermittlung der Effekte der mechanischen Substratvorbehandlung mit dem Querstromzerspaner auf den spezifischen Methanertrag und die Abbau-geschwindigkeit von nachwachsenden Rohstoffen und Pferdemist im Labormaßstab; 3. Untersuchungen zur Verwertbarkeit von Pferdemist im Praxismaßstab und den Einflüssen der mechanischen Aufbereitung auf den Biogasprozess an der Forschungsbiogasanlage „Unterer Lindenhof“. Eine Verwertung von strohhaltigem Pferdemist im Biogasprozess ist möglich. Allerdings muss eine Verunreinigung mit alternativen Einstreumaterialien aufgrund der geringen Abbaubarkeit vermieden werden. Zudem konnte ein erheblicher Verlust des Methanpotenzials durch eine Zwischenlagerung und der dadurch stattfindenden aeroben Rotte nachgewiesen werden. Aufgrund hoher Trockensubstanzgehalte und geringer Gehalte von essentiellen Mikro- und Makronährstoffen sollte der Einsatz von Pferdemist in Biogasanlagen nur mit geeigneten Co-Substraten erfolgen. Die mechanische Aufbereitung mittels Querstomzerspaner von Silagen und Pferdemist führte zu einer signifikanten Reduktion der Partikelgröße und Steigerung der Substratoberfläche. Es wurden jedoch keine signifikanten Veränderungen des spezifischen Methanertrages der untersuchten Silagen durch die Vorbehandlung festgestellt. Bedingt durch die Vergrößerung der Substratoberfläche wurde bei der Grassilage und der Getreide-Ganzpflanzensilage eine Steigerung der Abbaugeschwindigkeit nachgewiesen. Die mechanische Desintegration von Pferdemist resultierte in einer signifikanten Steigerung des spezifischen Methanertrags und einer deutlichen Verbesserung der Abbaukinetik. Bei der Betrachtung der Energiebilanz der Zerkleinerung konnte nur für die Aufbereitung der rohfasereichen Substrate ein positives Ergebnis erzielt werden. Dementsprechend ist eine vorherige Desintegration von Silagen für die Biogaserzeugung nicht zu empfehlen. Die Ergebnisse aus den Untersuchungen zur Verwertbarkeit von unbehandelten und mechanisch aufbereiteten Pferdemist im Praxismaxstab zeigen, dass der Einsatz von unzerkleinertem Pferdemist zu erheblichen verfahrenstechnischen Problemen führt und in unzureichenden Abbaugraden resultiert. Durch die mechanische Aufbereitung war ein störungsfreier Anlagenbetrieb möglich. Zusätzlich konnte eine sehr gute Substratausnutzung erzielt werden. Der zusätzliche Energieaufwand der mechanischen Intensivaufbereitung konnte durch den höheren Gasertrag weit mehr als ausgeglichen werden. Die Resultate der vorliegenden Arbeit zeigen, dass mit einer geeigneten Aufbereitungstechnik der Einsatz von Pferdemist und weiteren rohfaserreichen Strukturmaterialien in landwirtschaftlichen Biogasanlagen möglich ist. Eine vollständige Konversion des strohhaltigen Pferdemistes stellt ein Flächenäquivalent von bis zu 156.000 ha Maisanbaufläche dar. Damit liefert diese Arbeit einen wesentlichen Beitrag zur Steigerung der Nachhaltigkeit und Wirtschaftlichkeit der Biogaserzeugung und dem Erreichen der energiepolitischen Ziele. The increasing use of energy crops as the main feedstock and the resulting occupancy of arable land is the central point of criticism of the population in biogas production. Although waste and residues provide significant energy potentials, the conversion of these materials in the biogas process has not been established to date. Significant barriers are the widely varying composition of these materials and their substrate properties. In general, the residues contain a high percentage of fiber, which rises great challenges for the existing process technology. This work aimed to address these challenges by investigating the suitability and usability of the fiber-rich substrate horse manure for biogas production in continuously operated agricultural biogas plants. The study was divided into three consecutive 1. Investigation of the composition and usability of horse manure with different bedding materials and determination of the specific methane yields also taking into account the aging process degradation of horse manure; 2. Determination of the impact of mechanical pretreatment of the substrate with the cross-flow grinder on the specific methane yield and degradation kinetics of commonly used energy crops and horse manure in laboratory-scale; 3. Studies on the feasibility of horse manure in full-scale biogas processes and the effects of mechanical treatment at the research biogas plant "Unterer Lindenhof”. The use of straw-based horse manure in the biogas process is feasible. However, contaminations with alternative bedding materials due to their low degradability must be avoided. Furthermore, a substantial loss of methane potential could be detected due to the storage and meanwhile aerobic degradation. As a result of the high dry matter content and low levels of essential micro- and macro-nutrients, horse manure should only be utilized in biogas plants with suitable co - substrates. The mechanical treatment of silage and horse manure with the cross-flow grinder resulted in a significant reduction in particle size and increased substrate surface. However, no significant changes in the specific methane yield of the investigated silages were observed. Due to the increase of the substrate surface the degradation rate of the grass silage and whole crop silage accelerates. The mechanical disintegration of horse manure resulted in a significant increase of the specific methane yield and a significant improvement of the degradation kinetics. When considering the energy balance of the disintegration, a positive result could only be obtained for the processing of the fiber-rich substrates. Accordingly a previous disintegration of silage for biogas production is not recommended. The results from the investigation of the usability of untreated and disintegrated horse manure in the full-scale biogas process show that the use of horse manure without previous treatment causes serious procedural problems and results in insufficient degrees of degradation. The mechanical pretreatment guarantees a plant operation without failures during this trial. Additionally a complete substrate utilization can be achieved due to the treatment. The additional energy expenditure for the operation of the cross flow grinder was overcompensated by the higher gas yield. The results of this study show, that with a suitable treatment technology, the use of straw based horse manure and other high fiber structural materials in agricultural biogas plants is possible. A complete conversion of straw based horse manure provides an energy equivalent of up to 156,000 ha of maize. Thus, this study helps to improve the sustainability and profitability of biogas production and the achievement of the energy policy objectives.

International audience; This study aims to evaluate the impact of pretreatment on the anaerobic digestion of wheat straw and other lignocellulosic materials. For that, an original procedure named “Anaerobic Respirometry” is used as a tool to monitor the Methane Production Rate (MPR) of treated and untreated materials, allowing determining the impact of pretreatment in terms of CH4 production and degradation kinetics. Results from various grinding technologies, namely impacts mill, knife mill, air-jet mill, ball mill illustrate this procedure. The MPR experimental curves obtained for pretreated substrates show two distinct peaks in the methane production rate. This can result from an accumulation of acetate which is then consumed and gives rise to the second peak. A second hypothesis can also involve a phenomenon of bacteria colonization on the cellulose delaying methane production. Although this double peak complicated the results interpretation, CH4 production over the 10 days period was determined from the MPR in order to evaluate the impact of the mechanical pretreatment on the anaerobic digestion efficiency. The results demonstrate an increase up to 44% in CH4 production from 122 for the knife mill sample up to 175 NLCH4/kgVS for samples grinded by ball mill.

Modern mechanical-biological waste treatment plants for the stabilization of both the source-separated organic fraction of municipal solid wastes (OFMSW) and the mixed stream of municipal solid wastes (MSW) include a mechanical pretreatment step to separate recyclable materials such as plastics, glass or metals, before biological treatment of the resulting organic material. In this work, the role of storage and mechanical pretreatment steps in the stabilization of organic matter has been studied by means of respiration techniques. Results have shown that a progressive stabilization of organic matter occurs during the pretreatment of the source-separated OFMSW, which is approximately 30% measured by the dynamic respiration index. In the case of mixed MSW, the stabilization occurring during the reception and storage of MSW is compensated by the effect of concentration of organic matter that the pretreatment step provokes on this material. Both results are crucial for the operation of the succeeding biological process. Finally, respiration indices have been shown to be suitable for the monitoring of the pretreatment steps in mechanical-biological waste treatment plants, with a strong positive correlation between the dynamic respiration index and the cumulative respiration index across all samples tested.

A modified twin-screw extruder incorporated with a filtration device was used as a liquid/solid separator for xylose removal from steam exploded corncobs. A face centered central composite design was used to study the combined effects of various enzymatic hydrolysis process variables (enzyme loading, surfactant addition, and hydrolysis time) with two differently extruded corncobs (7% xylose removal, 80% xylose removal) on glucose conversion. The results showed that the extrusion process led to an increase in cellulose crystallinity, while structural changes could also be observed via SEM. A quadratic polynomial model was developed for predicting the glucose conversion and the fitted model provided an adequate approximation of the true response as verified by the analysis of variance (ANOVA).