Promoting Sustainability: Wastewater treatment plants as a source of biomethane in regions far from a high-pressure grid. A Portuguese case study

Wastewater treatment plants (WWTP) located in regions far from a high-pressure grid can produce renewable biomethane, which can partially substitute the natural gas locally consumed. However, the economic viability of implementing biomethane plants in WWTP has to be guaranteed. This paper uses the discount cash flow method to analyze the economic viability of producing biomethane in a WWTP located in Évora (Portugal). The results show that, under the current conditions, it is unprofitable to produce biomethane in this WWTP. Since selling the CO2 separated from biogas may result in an additional income, this option was also considered. In this case, a price of 46 EUR/t CO2 has to be paid to make the project viable. Finally, the impact of potential government incentives in the form of feed-in premia was investigated. Without selling CO2, the project would only be profitable for feed-in premia above 55.5 EUR/MWh. If all the CO2 produced was sold at 30 EUR/t CO2, a premium price of 20 EUR/MWh would make the project profitable. This study shows that the economic attractiveness of producing biomethane in small WWTP is only secured through sufficient financial incentives, which are vital for developing the biomethane market with all its associated advantages

Catalytic Converters for Vehicle Exhaust: Fundamental Aspects and Technology Overview for Newcomers to the Field

This works aims to provide an understanding on basic chemical kinetics pertaining to three-way catalytic (TWC) converters from an educational perspective, aimed at those novel readers in this field. Rate of reactions and its factors are explained, showcasing that the chosen catalyst is the main factor affecting the overall rate of reaction. Furthermore, this overview revisit insights of the catalytic converter structure and the environmental issues that come along with it. Lastly, the chemical and physical properties of the reactants and products-pollutant and less-toxic gases—are discussed, in order to gather a better understanding of the reactants and products that enters a catalytic converter

Biogas upgrading through calcium looping: Experimental validation and study of CO2 capture

The calcium looping technology is one of the most promising technologies for capturing and storing CO2. This technology has been evaluated with a variety of sorbents and conditions in previous works, but the inlet CO2-ladden gas has typically been a flue gas from combustion, which typically has a composition of 10–20% CO2 and 80–90% N2. On the other side, the performance of the calcium looping process for CO2 capture of other gases (i.e., biogas or gases resulting from hydrothermal carbonization) remains largely unstudied. In this work, this knowledge gap is assessed through evaluating the performance of the calcium looping process for biogas (synthesized as 40% CO2, 60% CH4) in terms of carbonation conversion. This experimental study investigates the impact of: (1) using an inlet gas composition representative for biogas instead of combustion flue gas; (2) different biogas compositions; (3) the carbonation temperature; (4) the cooling-down and heating-up of the sorbent material between the reactor and ambient temperatures within cycles; (5) the atmosphere composition during calcination; and (6) the solids particle size. The main result obtained is that the overall CO2-capture performance of calcium looping improves when using biogas as inlet CO2-ladden gas, in comparison with combustion flue gas. One main contribution to this improved performance is shown to be the presence of secondary reactions (i.e., dry reforming, methanation). The impact of the CH4 to CO2 ratio tested is not remarkable, showing that the potentialities of the process in this aspect can be adapted to several biogas producing feedstocks

Effluents and residues from industrial sites for carbon dioxide capture: a review

The adverse effects of climate change calls for the rapid transformation of manufacturing processes to decrease the emissions of carbon dioxide. In particular, a lower carbon footprint can be achieved by capturing carbon dioxide at the site of emission. Here we review the use of industrial effluents, waste and residues to capture carbon dioxide. Waste include steelmaking slag, municipal solid waste incinerator ashes, combustion fly ash, black liquor, paper mill waste, mining waste, cement waste, construction and demolition waste, waste from the organic industry, and flue gas desulfurization gypsum waste. Capture capacities range from 2 to 800\ua0kg of carbon dioxide per ton of waste, depending on processes, waste type and conditions. Cement waste and flue gas desulfurization gypsum\ua0waste show the highest capture capacity per ton of waste

Sinorhizobium fredii Strains HH103 and NGR234 Form Nitrogen Fixing Nodules With Diverse Wild Soybeans (Glycine soja) From Central China but Are Ineffective on Northern China Accessions

Sinorhizobium fredii indigenous populations are prevalent in provinces of Central China whereas Bradyrhizobium species (Bradyrhizobium japonicum, B. diazoefficiens, B. elkanii, and others) are more abundant in northern and southern provinces. The symbiotic properties of different soybean rhizobia have been investigated with 40 different wild soybean (Glycine soja) accessions from China, Japan, Russia, and South Korea. Bradyrhizobial strains nodulated all the wild soybeans tested, albeit efficiency of nitrogen fixation varied considerably among accessions. The symbiotic capacity of S. fredii HH103 with wild soybeans from Central China was clearly better than with the accessions found elsewhere. S. fredii NGR234, the rhizobial strain showing the broadest host range ever described, also formed nitrogen-fixing nodules with different G. soja accessions from Central China. To our knowledge, this is the first report describing an effective symbiosis between S. fredii NGR234 and G. soja. Mobilization of the S. fredii HH103 symbiotic plasmid to a NGR234 pSym-cured derivative (strain NGR234C) yielded transconjugants that formed ineffective nodules with G. max cv. Williams 82 and G. soja accession CH4. By contrast, transfer of the symbiotic plasmid pNGR234a to a pSym-cured derivative of S. fredii USDA193 generated transconjugants that effectively nodulated G. soja accession CH4 but failed to nodulate with G. max cv. Williams 82. These results indicate that intra-specific transference of the S. fredii symbiotic plasmids generates new strains with unpredictable symbiotic properties, probably due to the occurrence of new combinations of symbiotic signals.España, Junta de Andalucía P11-CVI-7500España Ministerio de Economía y Competitividad BIO2016-78409-

Synthetic Slag Production Method Based on a Solid Waste Mix Vitrification for the Manufacturing of Slag-Cement

Herein an innovative process to develop a potential vitreous material with cementing properties is proposed. This process paves a production path through melting industrial waste and subsequently cooling the casting in water. The idea erases the need to reduce the environmental impact of the cement industry in terms of natural resources consumption as well as the re-utilization of abandoned wastes from other industries. The recycled industrial wastes were selected according to the amount of waste produced in the industrial field and its suitable chemical composition, such as construction and demolition waste and/or shells from shellfish. As a main result, the mechanical properties showed by our novel material were worse than those reported by blast furnace slag (25–28 MPa for two different proportions) for seven days and better (43–52 MPa for two different proportions) for 28 days. The rest of the properties evaluated were in agreement with the standards’ requirements. Hence, this novel process would help to minimize the environmental impact of these wastes at the same time that their use in the cement industry would reduce the consumption of raw materials.Gobierno de España ITC-2011101

UE side Application Layer metrics For QoE-based Network Management.

Cellular networks are being improved by the automation of management tasks in order to optimize the performance while improving the efficiency. This is based on the vast amount of data which is available from the network side. Nonetheless, the network side perspective is limited and the focus is being redirected to the user side. Here, Drive Tests are in charge of collecting useful information, but at high costs. Thus, the present work presents a key source of information regarding network management: user side application layer metrics. In this regard, this work exploits this user side data by using different techniques to estimate the users’ quality of experience with the aim of network management.This work was supported by the project MUSE (Massive User Experience Assessment and Prediction for Mobile Networks) - Ref. UMA-CEIATECH-15, and the Spanish Ministry of economic affairs and Digital Transformation and European Union - NextGenerationEU within the framework “Recuperación, Transformación y Resiliencia y el Mecanismo de Recuperación y Resiliencia” - project MAORI, and Univer- sidad de Málaga through the “II Plan Propio de Investigación, Transferencia y Divulgación Científica” This work was possible thanks to the partnership with Metricell Limited to provide a very large dataset of anonymized metrics from real cellular network users. This work has been also funded by: Spanish Ministry of Universities - Ref. FPU20/02863

Insights into Photosensitized Reactions for Upgrading Lignin

The conversion of lignin into valuable chemical products is important for the shift away from the petrochemical industry toward a more sustainable system of biorefineries. However, the recalcitrance and heterogeneity of lignin have made its selective depolymerization a difficult task. Photochemical methods of lignin conversion are being investigated because of the potential to operate photoreactors at milder temperatures and pressures than thermal methods and to achieve efficient reaction pathways. Furthermore, light-driven reactions facilitate reaction pathways that cannot be accessed by conventional/thermal methods. Most of the current research focuses on photocatalytic methods, which are interesting due to their potentially high selectivity, but come with the disadvantage of catalyst costs and separation requirements. In this work, we continue our investigation into the use of ultraviolet light-emitting diodes, which aims to utilize the advantages of photochemistry, while avoiding the use of expensive catalysts. Photosensitizers can participate in energy transfer, electron transfer, and hydrogen abstraction in photochemical reactions. Here, we investigated the effects of a common photosensitizer, benzophenone, on the photochemical conversion of lignin, and 2-(benzyloxy)phenol (2BP), a compound with an ether bond between two aromatic units. We monitored the conversion reactions using complementary techniques of 1H nuclear magnetic resonance (NMR), diffusion NMR, and in situ Fourier transform infrared (FTIR) spectroscopy. For 2BP, the reactions with benzophenone progressed slower and without a difference in the final product formation. However, several differences were observed in photoreactions utilizing Kraft lignin and benzophenone compared to those without benzophenone. For example, a faster decay of the 1H NMR peak corresponding to aromatic/phenolic protons and different changes in the shape of methoxy peaks were observed, indicating the formation of different products. This work demonstrates that benzophenone participates in the photoreactions of Kraft lignin and that the photoreactions of Kraft lignin and 2BP are different. Depolymerization of lignin into smaller fragments was confirmed with diffusion NMR, both with and without the photosensitizer

Physicochemical comparison of precipitated calcium carbonate for different configurations of a biogas upgrading unit

BACKGROUND: This paper presents a physicochemical comparison of the solid products obtained from two alternative processes that recycle waste sodium carbonate (Na2CO3) solution, which is produced following the absorption of CO2 in a biogas upgrading unit. Chemical regeneration processes offer an attractive alternative to the energetically demanding standard physical methods. In the first process, sodium hydroxide (NaOH) is regenerated as a precipitate from the chemical reaction of Na2CO3 with calcium hydroxide (Ca(OH)2). The second process shows a path to obtain a valuable sodium chloride (NaCl) and calcium carbonate (CaCO3) rich brine from calcium chloride (CaCl2) acting as a precipitant agent. In both processes, precipitated calcium carbonate (PCC) is obtained as the most valuable by‐product, but with varying properties owing to the different origin. RESULTS: The purpose of this work is to analyze physicochemically both variations of PCCs obtained and examine the differences between these solid samples in order to determine which method produces more desirable characteristics in the final product. To this end, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were employed as characterization methods. The results reflect that both PCCs have a calcite crystal structure, or morph, being as both PCC products originate from CaCl2 that is more similar to commercial calcium carbonate calcite. CONCLUSION: These results confirmed that a pure CaCO3 valuable by‐product can be obtained from a biogas upgrading unit with several industrial applications.This work was supported by the University of Seville through V PPIT-US. Financial support for this work was also provided by EPSRC grant EP/R512904/1 as well as Royal Society Research Grant RSGR1180353. This work was also partially sponsored by CO2ChemUK through EPSRC grant EP/P026435/1. Furthermore, this work was supported by EMASESA through the NURECCO2 project and Corporación Tecnológica de Andalucía (CTA)

Electrocatalytic CO2 conversion to C2 products: Catalysts design, market perspectives and techno-economic aspects

The energy crisis caused by the incessant growth in global energy demand joint to its associated greenhouse emissions motivates the urgent need to control and mitigate atmospheric CO2 levels. Leveraging CO2 as carbon pool to produce value-added products represents a cornerstone of the circular economy. Among the CO2 utilization strategies, electrochemical reduction of CO2 conversion to produce fuels and chemicals is booming due to its versatility and end-product flexibility. Herein most of the studies focused on C1 products although C2 and C2+ compounds are chemically and economically more appealing targets requiring advanced catalytic materials. Still, despite the complex pathways for C2+ products formation, their multiple and assorted applications have motivated the search of suitable electrocatalysts. In this review, we gather and analyse in a comprehensive manner the progress made regarding C2+ products considering not only the catalyst design and the electrochemistry features but also techno-economic aspects in order to envisage the most profitable scenarios. This state-of-the-art analysis showcases that electrochemical reduction of CO2 to C2 products will play a key role in the decarbonisation of the chemical industry paving the way towards a low-carbon future