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This paper reveals the effect of calcium and magnesium ions in carbonation experiments carried out to regenerate sodium hydroxide from a biogas upgrading unit. This novel study arises as an alternative to standard physical process whose elevated energy consumption imposes economic restrictions. Previous works employed alkaline waste to turn them into value added product. Nevertheless, no attractive economical results were obtained due to the low regeneration efficiencies. Our hypothesis is that both calcium and magnesium waste composition percentages have an impact in the result, hence this work propose an isolated study aiming to determine the of each one in the global performance. To this end, the operational parameters (reaction time, reaction temperature and molar ratio) were tuned as well as physicochemical properties of the final solid samples were analyzed by several techniques. The results indicate that calcium is much more prone than magnesium to reach high efficiencies in aqueous carbonation experiments. Additionally, higher quality products were achieved with calcium. The results of this study suppose an important step for understanding the aqueous carbonation through waste in the path to achieve a more sustainable city and society.

In this work a novel strategy for bio-methane production and magnesium chloride waste valorization is addressed. The proposed process is a potential alternative path to the already existing biogas upgrading technologies by carbon dioxide mineralization into valuable magnesium carbonate. The main parameters affecting the precipitation efficiency (reaction time, reaction temperature, and molar ratio reactant/precipitator) are studied, leading to promising results which spark further investigation in this innovative route. Additionally the purity and the morphology of the obtained solid product was accurately analysed through different physicochemical characterization techniques such as Raman, X-Ray diffraction and Scanning electron microscope. The characterisation study reveals a mixture of Nesqueonite and Dypingite carbonate phases obtained in the process being the later the dominant phase in the resulting precipitate. Overall, the results discussed herein confirmed the technical feasibility of this innovative strategy for synergizing carbon dioxide mineralization and renewable energy production.

Herein a strategy for biogas upgrading in a continuous flow absorption unit using CaCl2 as capturing agent is reported. This process is presented as an alternative to the standard physical regeneration processes to capture carbon dioxide (CO2) from biogas effluents with inherent high energy penalties. This work showcases a systematic study of the main parameters (reaction time, reaction temperature, and molar ratio reactant/precipitator) affecting calcium carbonate (CaCO3) precipitation efficiency in a reaction between sodium carbonate (Na2CO3) and CaCl2. In addition, the purity and main characteristics of the obtained product were carefully analysed via in a combined characterization study using Raman, XRD, and SEM. Our results indicate that acceptable precipitation efficiencies between 62 and 93% can be reached by fine tuning the studied parameters. The characterization techniques evidence pure CaCO3 in a calcite structure. These results confirmed the technical feasibility of this alternative biogas upgrading process through CaCO3 production.

Acid mine drainage induced by the mining industry causes environmental and economic issues. Acid mine drainage contains mainly metals such as Fe, Al, Cu, Ca, Mg, Mn and Zn. Preventing the formation of acid mine drainage has not been found feasible. As a consequence, remediation treatments have been developed during the last years to remove metals and obtain high-quality water, which may be reused. We review here several treatment options such as selective metal precipitation, adsorption, electrochemical processes and membrane processes. Adsorption is the most employed commercially since it can recover 99% of the metals. Membrane processes are promising according to lab-scale results, notably because high-quality water is obtained. Further research is necessary to implement combination of technologies, e.g., adsorption membrane, at larger scales, as well as to obtain more valuable products that can balance the overall economy for the mining industry.

The scarcity of fossil fuels and the worldwide pollution have led the scientific community to seek renewable energy alternatives. In particular, biogas has become a potential alternative fuel to be employed instead of traditional energies. Biogas is mainly composed by methane (CH4) and carbon dioxide (CO2). To obtain pure biomethane, a proper biogas upgrading to remove CO2 and other minority compounds is needed. For this purpose, upgrading processes have been developed, such as water or chemical scrubbing, membrane separation, pressure swing adsorption, and cryogenic techniques. Cryogenic techniques represent a good option to be optimized because these techniques yield high-purity products, ranging between 95 and 99%. Therefore, we present here a review on cryogenic techniques. In spite of many advantages, the high-energy penalty makes cryogenic techniques commercially inapplicable actually. Several authors have proposed novel configurations to reduce the energy consumption. Cryogenic packed-bed technology was recently tested in a coal-fired plant with an energy consumption of 1.8 MJ/kg CO2. Economic analyses were carried out for anti-sublimation CO2 capture, giving a cost of 34.5 €/ton CO2. Among the different alternatives of cryogenic hybrid systems, cryogenic membrane processes stand out due to a 54.4% of capital cost savings.

This paper reveals a regeneration method for a carbonate compound after carbon dioxide (CO2) absorption in a biogas upgrading unit run with caustic mixtures, obtaining precipitated calcium carbonate (PCC) as valuable by-product. This process arises as an alternative to physical regeneration, which is highly energy intensive. This work provides novel insights on the regeneration efficiency of carbonates to hydroxides while also studying the influence of K+ or Na+ in the caustic CO2-trapping solution. The compared parameters were the reaction time, temperature and molar ratio. Moreover, psychochemical characterization of solids was obtained by means of Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM) images. The results indicate that regeneration efficiencies are slightly lower when potassium is used instead of sodium, but quite acceptable for both of them. The chemical characterization experiments showed the predominance of calcium carbonate. Overall, the results obtained in this study proved that this process is feasible to upgrade biogas through PCC precipitation, which appears to be a promising economically viable process to synergise CCS and CCU.

Biomethane production through biogas upgrading is a promising renewable energy for some industries which could be part of the equilibrium needed with fossil fuels consumption to achieve a sustainab...

Herein we analyze the profitability of a novel regenerative process to synergize biogas upgrading and carbon dioxide utilization. Our proposal is a promising alternative which allows to obtain calcium carbonate as added value productwhile going beyond traditional biogas upgrading methodswith high thermal energy consumption. Recently we have demonstrated the experimental viability of this route. In this work, both the scale-up and the profitability of the process are presented. Furthermore, we analyze three representative scenarios to undertake a techno-economic study of the proposed circular economy process. The scale-up results demonstrate the technical viability of our proposal. The precipitation efficiency and the product quality are still remarkable with the increase of the reactor size. The techno-economic analysis reveals that the implementation of this circular economy strategy is unprofitable without subsidies. Nonetheless, the results are somehow encouraging as the subsides needed to reach profitability are lower than in other biogas upgrading and carbon dioxide utilization proposals. Indeed, for the best-case scenario, a feed-in tariff incentive of 4.3 €/MWh makes the approach profitable. A sensitivity study through tornado analysis is also presented, revealing the importance of reducing bipolarmembrane electrodialysis energy consumption. Overall our study envisages the big challenge that the EU faces during the forthcoming years. The evolution towards bio-based and circular economies requires the availability of economic resources and progress on engineering technologies

In this work, a comprehensive discussion of forward osmosis membrane technology is presented. Forward osmosis is an interesting and promising system to concentrate multiple kind of solutions in different industrial areas as an alternative solution to classical water evaporation. Therefore, the number of publications and works related to this topic has considerably increased in the last years. Several aspects of forward osmosis have been discussed such as membrane fouling, concentration polarization phenomena, the different available draw solutions and the industrial applications in which forward osmosis has been applied. Cellulose triacetate membranes and thin-film composite membranes are the most employed nowadays. Chemical industry, desalination of drinking water, food industry and pharmaceutical industry are analyzed in deep since these are the most studied areas for forward osmosis application. Herein, the potential of forward osmosis for a sustainable industrial growth is widely proved in every sense.

Herein, a novel method for energy recovery from molten synthetic slags is analyzed. In this work, the potential energy that could be recovered from the production of synthetic slag is estimated by means of an integrated experimental&ndash, theoretical study. The energy to be recovered comes from the cooling&ndash, solidification stage of the synthetic slag manufacturing. Traditionally, the solidification stage has been carried out through quick cooling with water, which does not allow the energy recovery. In this paper, a novel cooling method based on metal spheres is presented, which allows the energy recovery from the molten slags. Two points present novelty in this work: (1) the method for measuring the metal spheres temperature (2) and the estimation of the energy that could be recovered from these systems in slag manufacturing. The results forecasted that the temperature achieved by the metal spheres was in the range of 295&ndash, 410 &deg, C in the center and 302&ndash, 482 &deg, C on the surface. Furthermore, we estimated that 325&ndash, 550 kJ/kg of molten material could be recovered, of which 15% of the energy consumption is in the synthetic slag manufacturing process. Overall, the results obtained confirmed the potential of our proposal for energy recovery from the cooling&ndash, solidification stage of synthetic slag manufacturing.

For sustainable growth, an economic model must tend toward a circular system, especially in the field of waste management. This work focuses on the valorization of spent fluid catalytic cracking catalyst from oil refineries, which generate 400,000 metric tons of spent catalyst per year worldwide, most of which is sent to landfills. A new alternative to landfilling is proposed for this waste, based on the combination of acid leaching for the recovery of lanthanum, a valuable rare earth, and the reuse of the leached solid residue as a cement substitute. A comparative life cycle assessment was made, including four environmental impact categories, i.e. global warming, fossil resource scarcity, mineral resource scarcity and water consumption, in order to quantify the potential environmental benefits of secondary lanthanum recovery from industrial waste with respect to primary lanthanum extraction from mineral resources. A maximum of 85.6% La recovery was achieved and 15 wt% of cement can be substituted with leached solid residue without changing the original cement classification. The waste management process presented in this paper promotes the sustainable management of the spent fluid catalytic cracking catalyst and contributes to the development of a new resource for a critical material such as lanthanum. The implementation of this novel waste management process could reduce global warming and mineral resource scarcity but would increase fossil resource scarcity and water consumption in comparison with primary La extraction.

© 2020 by the authors., Anaerobic digestion is a promising alternative to valorize agrifood wastes, which is gaining interest under an environmental sustainability overview. The present research aimed to compare anaerobic digestion with olive pomace oil extraction, by using life cycle assessment, as alternatives for the valorization of the olive mill solid waste generated in the centrifugation process with a two-outlet decanter from oil mills. In the case of olive pomace oil extraction, two cases were defined depending on the type of fuel used for drying the wet pomace before the extraction: natural gas or a fraction of the generated extracted pomace. The anaerobic digestion alternative consisted of the production of biogas from the olive mill solid waste, heat and electricity cogeneration by the combustion of the generated biogas, and composting of the anaerobic digestate. The life cycle assessment showed that anaerobic digestion was the best alternative, with a global environmental impact reduction of 88.1 and 85.9% respect to crude olive pomace oil extraction using natural gas and extracted pomace, respectively, as fuel., This research was funded by the Spanish Ministry of Economy and Competitiveness by Project CTM2014-55095-R.

9 Figuras.-- 4 Tablas, A novel analysis addresses the economic viability of biomethane production from small biogas plants in South Spain, as a claim to promote the use of green energy and reduce the consumption of natural gas. To this end, the importance of governmental incentives to reach profitability in biomethane plants is illustrated through a case study. To date, no study addressing this problem specifically for South Spain can be found. The study considers the whole process from biogas production to biomethane feeding into the grid, for three different biomethane capacities (50, 100 and 150 m3/h) and includes an exhaustive sensitivity analysis. For the three cases, implementing a biomethane plant is not viable and, therefore, not attractive for investors. Results considering biomethane governmental incentives as feed-in premia show significant improvements on the profitability of the largest plants. For example, supporting 150 m3/h biomethane production capacity plants with a premium price of only 6 €/MWh (6.6 cents/m3) results in 270 k€ NPV. Nevertheless, the smallest biomethane plants are hardly feasible. Concerning governmental support through investment subsidies, 150 m3/h plants are profitable if 10% of the investment is subsidized, whereas the smallest plants do not reach profitability even if 50% of the investment is subsidized., This work was supported by University of Seville through V PPIT-US, by FCT – Fundação para a Ciência e Tecnologia, Portugal (project UID/EMS/50022/2019) and by the Spanish Ministry of Economy and Competitiveness (project CTM2017-83870-R).

This paper presents a comprehensive list of Carbon Capture and Utilization technologies and applications, ranging from lab-scale R&D activities reported in academic papers to commercially establish...

All building materials contain amounts of natural radioactive nuclides and heavy metals, but when waste materials are to be used in building materials, industrial processing can lead to further enhancement of the concentrations of nuclides and heavy metals in the waste. In this paper fly ashes were used as a raw material to replace natural clay to make fired bricks. The effects of a high replacement ratio (from 0% to 100%) of clay with fly ash on the mechanical, radiological and leaching properties of bricks were analyzed. A study of the different sintering temperatures of bricks was carried out at the selected temperatures of 800, 900 and 1000 °C. When the temperature was increased the mechanical strength was also increased. Two leaching tests (one batch and the other monolithic) were carried out and the bricks with a high replacing ratio did not present problems regarding the heavy metal leaching in either test. The contents of three radionuclides (220Ra, 232Th and 40K) were analyzed and the Activity Concentration Index of the bricks was calculated and was lower than 1, indicating a radiation exposure lower than 1 mSv y−1.

The reuse of two wastes from coal combustion in the manufacture of panels to be used as building materials or in the protection of metal structures against fire was analysed in this study. The panels were composed of 100% coal combustion by-products. The wastes used were fly ashes and flue gas desulfurisation gypsum from the combustion of coal in a Spanish power plant. The gypsum was previously calcined for 6 h at 150°C. Different mixtures of gypsum and fly ash were tested. The mixtures were kneaded with water until a homogeneous paste was achieved, with which moulds were filled. After 28 d at ambient temperature, the panels were subjected to different physical (density, pH and humidity), mechanical (compressive strength and surface hardness) and fire-resistance tests. Moreover, leaching tests were applied to the fly ash and gypsum. The results obtained were evaluated with the requirements established in some European standards for commercial gypsum products. The fire resistance of the panels under study was found to be higher than that of commercial gypsum and they also showed good mechanical properties.

31 Páginas .-- 5 Figuras.-- 6 Tablas, This study proposes a biorefinery approach system to treat two berry extrudates generated by the berry-tasted products industry. The berry extrudates studied were strawberry extrudate (SE1 and SE2) and raspberry extrudate (RE), both of them processed in the same industrial plant. The proposed biorefinery approach consists in the extraction of bioactive compounds after hydrothermal pre-treatment followed by anaerobic digestion of the remaining biomass after extraction. A high concentration of valuable phenolic compounds was extracted from each extrudate through the absorption-desorption processes, i.e. 876, 392 and 2402 mg of gallic acid equivalents/kg extrudate in SE1, SE2 and RE, respectively. Anaerobic digestion of the remaining biomass after extraction led to high methane production, between 371 and 503 mL CH4/g VS. The economical evaluation showed that the proposed biorefinery approach would offer higher benefits than just anaerobic digestion of the untreated extrudate, although this last option would be economically feasible as well., The authors are very grateful to the Spanish Ministry of Economy and Competitiveness for funding this research through the project CTM2017-83870-R and the Ministry of Economy and Competitiveness Ramon y Cajal Programme (RyC 2012-10456). The authors also wish to thank to Dr. Bernabé Alonso-Fariñas for the revision of the manuscript.

This paper studies the feasibility of utilizing co-combustion fly ashes for the production of eco-friendly fired bricks. The fly ashes from co-combustion of coal and pet coke in a Spanish Power Plant were used as raw material to replace clay to make fired bricks. The effect of fly ash with high replacing ratio (from 0 to 80%) of clay on properties of bricks was analysed. The specimens, cylinders with 32.5 mm diameter and 50 mm length, were manufactured by compressing at 10 MPa. Different firing temperatures, 800, 900 and 1000 °C, were studied. The fired bricks with high volume ratio of fly ash present a high compressive strength and a low water absorption capacity. With increase in firing temperature, the compressive strength increased and the water absorption decreased. With increase in replacing ratio, the compressive strength decreased and the water absorption ratio increased. The bricks no present environmental problems according to the leaching study.

This paper presents an experimental analysis on a new board composed of gypsum and fly ashes from coal combustion, which are mutually compatible. Physical and mechanical properties, sound absorption coefficient, thermal properties and leaching test have been obtained. The mechanical properties showed similar values to other commercial products. As far as the acoustic insulation characteristics are concerned, sound absorption coefficients of 0.3 and 0.8 were found. The board presents a low thermal conductivity and a fire resistance higher than 50 min (for 4 cm of thickness). The leaching of trace elements was below the leaching limit values. These boards can be considered as suitable to be used in building applications as partitions.

Within the framework of a sustainable economy, industrial effluent management currently faces minimal liquid discharge or zero liquid discharge processes. To reduce energy consumption, forward osmosis has been introduced into zero liquid discharge system. The main disadvantage of forward osmosis is the high-energy consumption of the draw solution regeneration. Herein the regeneration stage is subjected to a techno-economic analysis using a novel membrane technology known as cascading osmotically mediated reverse osmosis. The objective of this work was the techno-economic study of water recovery from real effluents from the metallurgical industry, using a novel combined novel system. The liquid effluents employed in this work were real currents provided by Atlantic Cooper (Huelva, Spain). The experimental results showed that up to 75% of water can be recovered (for 20 L/m2·h at 20% of sodium chloride). The specific energy consumption and economic cost of the novel hybrid process were estimated as 7.4 kWhe/m3 and 6.05 $/m3 of recovered water, respectively. Thus, this novel proposal seems a promising alternative for zero liquid discharge systems in the metallurgical industry.

This paper focuses on developing a highway noise barrier prototype mainly composed of bottom ash from the traditional pulverised coal combustion at semi-industrial scale, following a simple and low-cost manufacturing procedure similar to that used to cast commercial concrete noise barriers. In order to obtain good sound absorption coefficients, a multilayer product was designed, with a porous layer in the incident noise face followed by the finest material in the back layer. The characterisation of the recycled multilayer product was carried out in accordance with the current European standard for road traffic noise reducing devices and the results have been compared to the specifications stated by the regulations. The acoustic performance has been evaluated by determining the sound absorption coefficient and the airborne sound insulation in a reverberation room. Regarding the non-acoustic performance, the physical (open void ratio, unit weight), mechanical (compressive strength, Young’s modulus, flexural strength, fracture energy, indirect tensile strength, characteristic length, impact strength) and fire resistance properties were determined. From the results obtained, bottom ash from traditional pulverised coal combustion can potentially be recycled by manufacturing a multilayer product that complies with the specifications required for road traffic noise reducing devices according to the European standards, and that reaches the same acoustic category as other commercial products used for the same application.

The development of robust and cost-effective hot gas filtration technologies is crucial to facilitate the implementation of advanced coal-based power systems. Understanding the structural characteristics of the dust cake, such as porosity, in relation to the pressure drop evolution is a subject of interest to improve the filtration process. This paper focuses on the study of dust cake compaction and its influence on cake porosity. A semi-empirical model based on Kozeny–Carman equation has been applied to experimental data from the operation of four types of commercial filters (two bag filters and two rigid filters) in a hot gas filtration experimental facility. The method proposed calculates the cake porosity from the specific dust cake resistance coefficient and dust properties. Cake porosity values obtained have been analysed to determine the effect of the operating parameters (filtration velocity, temperature and filtering media). Results show that filtration velocity is the variable that most affects the dust cake porosity. In addition, a correlation between filtration velocity and dust cake porosity has been established.

This article describes a number of tests that have been carried out using a pilot electrostatic precipitator (ESP) which operates with flue gases from a coal power plant. The purpose of these tests was to show the influence of the characteristics of the ash (resistivity) and the main design variables of an ESP (type of discharge electrode and collecting plate spacing) on the fouling of plates and discharge electrodes and the reentrainment of dust. Two types of coal, with high and low resistivity ashes, respectively, three types of discharge electrodes, and three typical collecting plate spacings were used in the tests. In fouling tests, the dust emission growth rate during periods with no rapping, the maximum permissible rapping interval, and the recuperation rate of the dust emission level after rapping were characterized. The maximum permissible rapping interval was defined as the time in which no alteration is observed in the operational variables of the ESP. In rapping tests, the relative increase of the dust emission level due to reentrainment was also characterized. The results of these tests have made possible to identify, for each of the tested coals, the ESP configurations (plate spacing and type of electrode) less sensitive to the formation of a permanent layer of ash and to the particle reentrainment due to rapping. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 7–14, 2015

The improvement of gas cleaning technologies is crucial for the establishment of advanced clean power generation coal-based technologies such as Integrated Gasification Combined Cycle (IGCC) or Pressurised Fluidized Bed Combustion (PFBC) which need high performance of the syngas clean-up process. New materials and advanced operating strategies at higher temperatures that could give lower energy penalty are required to be developed. A large scale high temperature filtration pilot plant is available at the ETSI University of Seville. This pilot plant allows testing different filtering elements and pulse cleaning strategies using real coal ash under an extensive range of operating temperature and pressure. The aim of the research is the evaluation of the alternatives for hot gas filtration technologies and the optimisation of the operation and performance of the filtering elements. An experimental campaign was carried out to test a new type of silicon carbide candle. Some prototype candles were fabricated from pyrolysed wood and other materials as result of a novel environment friendly patented process (BioSiC®). This process provides good thermo-mechanical, chemical and structural stability in an extensive range of temperatures. Main parameters for the characterisation of the prototype were studied such as filtration velocity, permeability, porosity, pressure drop across the filter, cleaning pulse interval, baseline pressure drop, filtration efficiency and durability of the filter. Optimal operating conditions and pulse cleaning strategies were determined. Additionally, a model to predict the behaviour of the filtering elements under diverse operating conditions was developed. In general, the experimental results showed that the prototypes are suitable for industrial applications under the operating conditions, typical of those required for hot gas cleaning of coal combustion and gasification gases, as used in this study. However, the possible improvements in the performance of the elements were identified that should be carried out in the next experimental campaign. This paper describes the main characteristics of the new material developed as well as the major results and conclusions from the analysis.

A semi-industrial filtration facility is currently in operation at the ETSI-University of Seville, with financial support from the European Commission and the Spanish Ministry of the Environment. This pilot plant allows testing different elements and reverse-flow pulse cleaning strategies using real coal ash and under diverse operating conditions such as temperature and pressure. The aim of the on-going research is the evaluation of the alternatives for hot gas filtration technologies and the optimisation of the operation and performance of the filtering elements. The first experimental campaign carried out in the filtration facility commenced in 2005. Four types of elements were tested at maximum temperature and pressure of 235 °C and 7.5 barg respectively. This paper describes the main results obtained during the second phase of the experimental campaign, in which the temperature was increased up to 370–550 °C. Three types of elements (one type of bag filter and two types of candles) were tested. Main parameters investigated for the characterisation of the filtering elements performance were the pressure drop across the element, the cleaning pulse interval, the baseline pressure drop, the filtration efficiency and the durability of the elements. Dependences on the particle loading and temperature among others were also established. Results obtained and conclusions extracted provide a useful tool for the implementation of the filtration technologies at industrial scale.

A high temperature high pressure filtration facility is available at the ETSI-University of Seville, which allows testing different elements and cleaning reverse-flow pulse strategies using real coal ash under diverse operating conditions. The facility is capable of processing 850 Nm 3 /h gas flow rate at maximum temperature and pressure of 550 °C and 7.5 barg respectively. An extensive testing campaigns have been carried out with the aim of evaluating alternatives for hot gas filtration technologies and optimising the performance of commercial filtering elements. In this framework, this paper focuses on a semi-empirical model developed for predicting the rise of the pressure drop with time. The model is based on theoretical considerations and the application of the experimental data generated using four filtering elements (PTFE and 3MFB700 bag filters, DSN1020 and CS1150 rigid filters). Nonlinear regression has been used to estimate and validate the coefficient of the model (specific dust cake coefficient) with arbitraries relations between independent and dependent parameters, by using iterative estimation algorithms. This is a valuable tool to select the best filtration options and optimum cleaning strategies in high temperature applications. Investigations about the factors affecting the specific dust cake resistance coefficient (filtration velocity, temperature, filter medium) are also presented.

The scope of this investigation is to develop a material mainly composed (80% w/w) of ceramic wastes that can be applied in the manufacture of road traffic noise reducing devices. The characterization of the product has been carried out attending to its acoustic, physical and mechanical properties, by measuring the sound absorption coefficient at normal incidence, the open void ratio, density and compressive strength. Since the sound absorbing behavior of a porous material is related to the size of the pores and the thickness of the specimen tested, the influence of the particle grain size of the ceramic waste and the thickness of the samples tested on the properties of the final product has been analyzed. The results obtained have been compared to a porous concrete made of crushed granite aggregate as a reference commercial material traditionally used in similar applications. Compositions with coarse particles showed greater sound absorption properties than compositions made with finer particles, besides presenting better sound absorption behavior than the reference porous concrete. Therefore, a ceramic waste-based porous concrete can be potentially recycled in the highway noise barriers field. El objetivo de este trabajo es desarrollar un material absorbente acústico compuesto fundamentalmente por residuos cerámicos (80% p) que se pueda utilizar en la fabricación de dispositivos reductores de ruido de carretera. La caracterización del producto se ha llevado a cabo atendiendo a sus propiedades acústicas, físicas y mecánicas, determinando el coeficiente de absorción acústica a incidencia normal, porosidad abierta, densidad y resistencia a compresión. La absorción acústica de un material poroso está fuertemente determinada por el tamaño de poro y por la longitud dela probeta sometida a ensayo. De este modo, se ha analizado la influencia del tamaño de partícula del residuo cerámico y del espesor de las muestras estudiadas en las propiedades del producto final. Los resultados obtenidos se han comparado con los obtenidos para un hormigón poroso elaborado con árido grueso, que se ha tomado como producto de referencia tradicionalmente empleado en este tipo de aplicaciones. Las composiciones elaboradas con el residuo de mayor tamaño de partícula han mostrado mayor absorción acústica, incluso mayor que las del hormigón poroso comercial. Por tanto, un hormigón poroso elaborado con residuos cerámicos puede ser potencialmente empleado como material en la fabricación de barreras acústicas de carretera.

© 2015 Elsevier Ltd. This study investigated metal dynamics, and their bioavailability, before and after thermal pretreatment of olive mill solid waste (OMSW), using a sequential metal extraction scheme. The 11.5% increase of cobalt in the most available fraction after the pretreatment coupled to the increase of methane production rate have been a good indicator that the OMSW anaerobic digestion might be metal limited due to the lack of cobalt., The authors wish to express their gratitude to the Spanish “Ministerio de Economia y Competitividad” (project CTM2014-55095-R) for providing financial support. The authors acknowledge funding within the framework of the COST Action 1302 (‘European Network on Ecological Roles of Trace Metals in Anaerobic Biotechnologies’)