Search Results (77)

The sustainable processing of coffee requires not only improving the efficiency of conventional operations but also advancing the recovery and valorization of bioactive compounds across the coffee value chain. In this context, emerging technologies offer eco-efficient alternatives to conventional extraction methods. This review summarizes recent advances in ultrasound-assisted extraction (UAE), high-pressure extraction (HPE), cold atmospheric plasma (CAP), and microwave-assisted extraction (MAE) applied to coffee beans and major coffee side streams, including pulp, husk, parchment, silverskin, and spent coffee grounds. The physicochemical principles of each technology, the main operating parameters, and their influence on extraction yield, phenolic composition, antioxidant capacity, and heat-sensitive compound preservation are discussed. Furthermore, potential synergies between combined techniques (UAE-MAE or HPE-UAE) and trends toward industrial scaling and integral valorization within a circular economy framework are highlighted. Overall, the evidence indicates that emerging technologies can intensify coffee extraction processes, increase phenolic recovery (often achieving up to two-fold improvements in total phenolic content compared to conventional techniques), and significantly reduce processing times (commonly reaching 2.5–15 min), supporting more sustainable and industrially relevant value chains. Full article

The transition toward a circular, sustainable food industry requires efficient valorization of biological resources while minimizing environmental pressures. This critical review focuses on the sustainable use of bioactive compounds recovered from plant-based waste and side streams through green extraction technologies as a core element of circular economy strategies in the agri-food sector. By integrating EUROSTAT indicators, a multivariate analytical approach, combining correlation analysis, principal component analysis (PCA), K-means clustering, and agglomerative hierarchical clustering (AHC), was employed to assess the relationships between greenhouse gas emissions, energy productivity, economic activity, and environmental employment across European States. The results reveal two main structural dimensions that explain nearly 90% of the total variability, reflecting the balance between economic scale and environmental pressure, and the role of energy efficiency in supporting sustainable consumption. Cluster analysis identified converging economies with greater circularity potential and structurally distinct economies that require targeted transition pathways. These findings emphasize that circular bioeconomy solutions, such as integrating green-extracted bioactive compounds into food products, must be tailored to each country’s economic and energy profile. This review highlights the strategic role of circular economy principles in strengthening the sustainability, resilience, and innovation capacity of the European food industry. Full article

Black liquor, the side stream from Kraft pulping, is a promising feedstock for the production of renewable fuels via hydrothermal liquefaction (HTL). However, further upgrading of the black liquor HTL oil is required to reduce the oxygen content for fuel use. In this work, the hydrodeoxygenation (HDO) of black liquor HTL oil model compounds was investigated to enhance the understanding of catalyst activity and selectivity under hydrothermal conditions. The study focused on isoeugenol and 4-methylcatechol as model compounds, representing different functionalities in black liquor-derived HTL-oil. Sulfided NiMo catalysts supported on titania, zirconia, activated carbon, and α-alumina were evaluated in batch mode at subcritical and supercritical upgrading using hydrogen gas. The results show that isoeugenol was fully converted in all experiments, while 4-methylcatechol conversion varied depending on the catalyst and reaction conditions. Phenols were obtained as the main products and the maximum degree of deoxygenation achieved was around 40%. This research provides insights into the potential of hydrothermal HDO for upgrading BL-derived biocrudes, emphasising the importance of catalyst selection and reaction conditions in hydrothermal conditions. Full article

Feedstock quality has been proven to be the single variable that most affects fluid catalytic cracking (FCC) unit performance, but catalyst characteristics have also been reported in the literature to have a considerable effect on cracking process performance. How these two main variables of the FCC process complement each other in the search for ways to optimize the performance of the FCC unit is the subject of current research. Twenty-one feedstocks with K_W-characterizing factors ranging from 11.08 to 12.06, Conradson carbon contents ranging from 0.05 to 12.8 wt.%, and nitrogen contents ranging from 800 to 3590 ppm (wt/wt) (basic nitrogen from 172 to 1125 ppm (wt/wt)) were cracked on 21 catalysts with micro-activity between 67% and 76% (wt/wt) in a laboratory-based advanced catalytic evaluation (ACE) unit at a reaction temperature of 527 °C, catalyst–to-oil ratios between 3.5 and 12.0 wt/wt, and a catalyst time on stream of 30 s. Some of the feeds and catalysts tested in the laboratory FCC ACE unit were also examined in a commercial short-contact-time FCC unit resembling a UOP side-by-side design. It was found that conversion can be very well predicted in both the laboratory ACE and the commercial FCC units using multiple linear correlations developed in this work from information about the following feed properties: K_W-characterizing factor, nitrogen content, and micro-activity of the catalyst. The coke on the catalyst that controls the catalyst-to-oil ratio and the regenerator temperature in the commercial FCC unit could be calculated using the correlations developed in this work for the laboratory ACE and commercial FCC units, based on feed characteristics and catalyst micro-activity. Due to the greater slope of the Δ coke/Δ micro-activity dependence observed in the ACE FCC unit, the more active catalysts show weaker results compared to the less active catalysts at a constant coke yield. In contrast, catalysts with higher activity are preferable for operation in the commercial FCC plant because they provide higher conversion at the same coke yield due to the lower slope of the Δ coke/Δ micro-activity relationship. Full article

This study represents comprehensive research that arises from the advanced sorption properties of zwitterionic resin beads, which were tested on simulated mono- and multicomponent heavy metal ion (HMI)-polluted water, compared to the stream collected in the Tarnita mine area. Ionic exchange resins (IExRs) were first synthesized in cationic form from a highly crosslinked (8%) acrylic copolymer, by introducing different side groups containing amino functionalities, such as ethylenediamine, triethylenetetramine, and hydrazine hydrate. The corresponding zwitterionic form of each IExR was obtained by reacting the cationic resins with sodium chloroacetate. The structures and morphologies of the synthesized resins were characterized using scanning electron microscopy and infrared spectroscopy. Successful removal of Cu(II), Fe(II), and Mn(II) was quantified by using atomic absorption spectroscopy. Tests with multicomponent synthetic solutions revealed the following typical order of retention: Cu(II) > Fe(II) > Mn(II). In the case of water samples collected from the Tarnita area, the zwitterionic resins were able to retain approximately 93.8% Mn(II), 94.7% Fe(II), and >95.5% Cu(II); in all instances, the concentration of Fe(II) was significantly higher than that of Cu(II) and Mn(II). Additionally, sorption isotherms, kinetics, and thermodynamic parameters were studied. Wheat germination was included to test the efficiency of the batch sorption using IExRs, compared to the stream collected from Tarnita, highlighting how the water cleaning process leads to healthy plant growth. The results demonstrate that, after IExRs sorption the tested HMIs content is below the permissible maximum level for surface water, effectively mitigating the pollution of the steam near to the Tarnita closed mine area, removing the main contaminants found in it. Full article

In Calabria coastal regions, seaward and landward sides could be connected through the ecological role of fluvial catchments. Calabria Tyrrhenian coast shows a wilderness area, characterized by two terrestrial and marine Special Areas of Conservation (SACs) connected by the fluvial catchment of Verri stream. The bibliographic search was realized according to a Preferred Reporting Items for Systematic Reviews and Meta-Analysis, as a standardized method for screening the most relevant literature. The field survey, conducted in the study area, highlighted high biodiversity levels and a great natural heritage represented by 189 plant species and 130 animal ones. According to the resulting data, the basin represents a classical model of ecological corridor linking terrestrial and marine SACs, as cornerstones of Natura 2000 network, so representing the European assessment for biodiversity conservation. This paper highlights the high biological richness of a wilderness area showing the tight relationship between the continental and the marine districts of the same coastal region. The main goal of the research is to remark the fundamental role of fluvial corridors within a regional approach where riverine catchments could represent the connecting steps of the network. In Calabria it is hopeful to establish a functional connectivity amongst protected areas supported by fluvial corridors along the regional basins. Full article

Biofuels, such as ethanol (CH₃CH₂OH), remain significantly underutilized globally despite their potential to mitigate environmental effects associated with fossil fuel combustion. Ethanol (ETH) can seamlessly blend with petroleum-derived gasoline, boosting its octane rating as a virtuous side effect. However, in several countries, octane number (ON) boosters such as methyl-tert-butyl-ether (MTBE) are still blended into the gasoline (also known as gas or petrol) sold in fuel stations, despite this being restricted or banned due to deleterious effects on the environment and health. Additionally, in nations overproducing naphtha from refining petroleum condensates, such as in the Middle East, investments in extra carbon chain rearrangement units can be an outlet to enhance gasoline production, since they produce high-ON streams; however, aromatic concentration becomes a limiting constraint. A discrete-event simulation algorithm combines sixteen main (primary) manufacturing variations into two secondary manufacturing and three supply chain variations, building gasoline yield and property plots over 512 gasoline production scenarios. Full article

Nowadays, the global brick industry utilizes billions of cubic meters of clay soil annually, resulting in the massive consumption of non-renewable resources. This study explores the viability of utilizing red marl from phosphate mining waste rocks for fired brick production. Ecofriendly fired bricks produced from 100% side streams (red marly clays (RM) and marble waste powder (MWP)) were prepared, pressed, dried at 105 °C, and then fired at 1100 °C for 1 h. The effects of marble waste powder addition (up to 30 wt%) on the physical, mechanical, mineralogical, and microstructural properties of the fired bricks were explored. The main results show that fired bricks with high compressive strength of a maximum of 39 MPa could be prepared with a mixture of red marl and 10 wt% of marble waste powder. The thermal conductivity was decreased by marble waste addition (from 0 to 30%) and was reduced from 0.93 W/m.k to 0.53 W/m.k; however, the compressive strength was also decreased to reach a minimum of 17 MPa. The firing shrinkage and density were also reduced with 30% marble waste by 41% and 18%, respectively. Therefore, red marly clays and marble waste could be promising raw materials for eco-fired brick production. Full article

This study presents a comprehensive flood-hazard assessment and mapping of the Messapios River catchment in Evia Island, Greece, utilizing a combination of Multi-Criteria Decision Analysis (MCDA) and Geographic Information Systems (GISs). Flood-prone zones were identified based on five critical factors, which were determined to be the most influential in the watercourse when excessive discharge overwhelms the drainage network’s capacity: slope, elevation, proximity to stream channels, geological formations, and land cover. The Analytic Hierarchy Process (AHP) was applied to assign weights to these factors, while the final flood-hazard map was generated using the Weighted Linear Combination (WLC) method. The analysis revealed that 17.8% of the catchment, approximately 39 km², falls within a very high flood-hazard zone, while 18.02% (38.91 km²) is classified as highly susceptible to flooding. The flood-prone areas are concentrated in the central, southern, and western parts of the study area, particularly at the lower reaches of the catchment, on both sides of the main streams’ channels, and within the gently sloping, low-lying fan delta of the river. The study area has high exposure to flood hazards due to the significant population of approximately 9000 residents living within the flood-prone zones, a fact that contributes to the area’s potential vulnerability. Additionally, critical infrastructure, including five industrial facilities, the Psachna General High School, the local Public Power Corporation substation, about 21 km of the road network, and 21 bridges are located within the zones classified as having high and very high flood-hazard levels. Furthermore, about 35 km² of economically vital agricultural areas (such as parts of the Psachna and Triada plains) are situated in highly and very highly prone to floods zones. MCDA proved to be an effective and reliable approach for assessing and mapping flood-hazard distribution in the Messapios River catchment. The results provide valuable insights to assist decision-makers in prioritizing intervention areas and efficiently allocate resources. Full article

As spillways are hydraulic structures constructed for the safe release of floodwater from the upstream (US) side of a dam to the downstream side, or from the end of canals and drains to a lower stream, the upstream water flow of such structures gains significant amounts of potential energy. As this water flows over a spillway or escapes, the gained potential energy is converted into kinetic energy, resulting in the water gaining an increasing velocity, thereby enhancing the flow’s destructive potential. This can have a harmful impact on the hydraulic performance and the structural stability of the spillway itself. To avoid such harmful effects, engineers and designers of such structures usually provide the spillways and water escapes with some tools for dissipating that kinetic energy and decreasing the flowing water’s velocity. The present study aims to enhance the performance efficiency of such dissipating tools, as well as to improve the quality of the flowing water by leveraging the significant turbulence generated by the existing energy dissipators on the back of the spillway body. The aeration process enabled by this turbulence increases the dissolved oxygen contents, thereby enhancing the water quality, which is one of the main objectives of this work. On the back surface of the spillway, various dissipater shapes with different geometrical configurations, dimensions, and combinations were tested, in order to determine the most suitable engineering treatments for maximizing the dissolved oxygen content and improving the water quality for various uses, as the study’s main goal. By testing 21 different model configurations with the available laboratory discharges, the study successfully identified the most effective shape and properties of the desired dissipator, which increased the dissolved oxygen content by an average of 21.70% and dissipated water energy by about 69%. Full article

Mycotoxin research is facing unprecedented challenges, starting from the urgent need to cope with the consequences of climate change, the global shortage of grain due to unstable political scenarios, and the major transformation of the supply chains after the COVID-19 pandemic. In this scenario, the mycotoxin contamination of human and animal foods is still unavoidable, thus representing a major challenge to global food security. Next to this, the shift to sustainable and circular food production might be accompanied by an increase in food safety issues involving mycotoxins, e.g., when new technologies are applied to reuse side streams from the food industry, it is not known if and how mycotoxins accumulate in these by-products. MycoTWIN is an EU-funded Horizon 2020 project which fosters knowledge transfer and scientific cooperation within the Mediterranean area, involving worldwide experts, decision makers, and stakeholders in the field of mycotoxigenic fungi and mycotoxins. The MycoTWIN project hosted working group meetings, whose aim was to propose operational plans and/or scientific strategic plans to shape the future research directions to better cope with these challenges. In the working group cycle “Future proof approaches for the management of toxigenic fungi and associated mycotoxins along the food chain”, a multi-actor group was guided in co-creation exercises to elaborate on future research directions and propose relevant actions to be implemented for the present to long-term time periods. The discussion focused on three main topics relevant to the assessment and management of risks associated with mycotoxins and toxigenic fungi: (i) needs for the harmonization of molecular and chemical methods and data analysis, (ii) from lab research to marketable solutions: how to fill the gap, and (iii) gaps in data quality for risk assessment. Full article

Most unmanned aerial vehicle (UAV) ground control station (GCS) solutions today are either web-based or native applications, primarily designed to support a single UAV. In this paper, our research aims to provide an open, universal framework intended for rapid prototyping, addressing these objectives by developing a Web Real-Time Communication (WebRTC)-based multi-UAV monitoring and control system for applications such as automated power line inspection (APOLI). The APOLI project focuses on identifying damage and faults in power line insulators through real-time image processing, video streaming, and flight data monitoring. The implementation is divided into three main parts. First, we configure UAVs for hardware-accelerated streaming using the GStreamer framework on the NVIDIA Jetson Nano companion board. Second, we develop the server-side application to receive hardware-encoded video feeds from the UAVs by utilizing a WebRTC media server. Lastly, we develop a web application that facilitates communication between clients and the server, allowing users with different authorization levels to access video feeds and control the UAVs. The system supports three user types: pilot/admin, inspector, and customer. Our research aims to leverage the WebRTC media server framework to develop a web-based GCS solution capable of managing multiple UAVs with low latency. The proposed solution enables real-time video streaming and flight data collection from multiple UAVs to a server, which is displayed in a web application interface hosted on the GCS. This approach ensures efficient inspection for applications like APOLI while prioritizing UAV safety during critical scenarios. Another advantage of the solution is its integration compatibility with platforms such as cloud services and native applications, as well as the modularity of the plugin-based architecture offered by the Janus WebRTC server for future development. Full article

The valorization of aquaculture/fishery processing by-products, as well as unavoidable/unwanted catches and discards in Greece, is currently an underutilized activity despite the fact that there are several best practices in Northern Europe and overseas. One of the main challenges is to determine whether the available quantities for processing are sufficient to warrant the valorization of discards and fish side streams. This is the first attempt to systematically record and analyze the available quantities of fish by-products and discards in Greece spatially and temporally in an effort to create a national exploitation Master Plan for the valorization of this unavoidable and unwanted biomass. A thorough survey conducted within the VIOAXIOPIO project unveiled a substantial biomass of around 19,000 tonnes annually that could be harnessed for valorization. Furthermore, the production of various High-Added-Value Biomolecules (HAVBs) was investigated and experimental trials were conducted to assess the potential yields, with the collected data used to formulate four valorization scenarios. Full article

Extra energy consumption, inefficient nitrogen removal, and excessive sludge production are major challenges faced by wastewater treatment plants (WWTPs) that rely on the traditional activated sludge process. Fermentation of wasted activated sludge (WAS) and novel nitrogen removal technologies based on partial nitrification (PN) have emerged as promising solutions to these issues. Recent studies have revealed an innovative strategy that integrates these two processes by supplementing fermentation liquid into activated sludge to induce PN. This review summarizes the research progress on PN establishment induced by the fermentation process. The microbiology and establishment methods of PN are briefly introduced, followed by a detailed discussion on the process, influencing factors, and product characteristics of WAS fermentation. The core section focuses on the side-stream and main-stream approaches of fermentation-induced PN, comparing their performance and application prospects. The potential mechanisms are explored, with an emphasis on the roles of free ammonia for the side-stream approach and the high tolerance of ammonium oxidizers to in-site fermentation stress for the main-stream approach. Finally, the limitations of the current research and future perspectives are discussed, highlighting the need for further investigation into microbial ecology, process optimization, and long-term stability. This review aims to provide insights into the synergistic integration of WAS fermentation and PN for sustainable and energy-efficient wastewater treatment. Full article

Wollastonite (CaSiO₃) is the most researched and well-defined mineral in the field of CO₂ mineralization, but it is also a sought-after process mineral and thus, not easily justified for large scale ex situ carbon sequestration, which requires an energy-intensive step of comminution to increase reactivity. Wollastonite-rich mine tailings are a side stream with an already fine particle size resulting from the extractive process, but their effective utilization is problematic due to legislation, logistics, a high number of impurities, and chemical inconsistency. In this study, the accelerated weathering (aqueous carbonation) of high-calcite (CaCO₃) wollastonite tailings was studied under elevated temperatures and high partial pressures of CO₂ to determine the carbon sequestration potential of those tailings compared to those of pure reference wollastonite originating from the same quarry. The main process variables were pressure (20–100 bar), temperature (40 °C–60 °C), and time (10 min–24 h). Despite consisting largely of non-reactive silicates and primary calcite, very fine tailings showed promise in closed-chamber batch-type aqueous carbonation, achieving a conversion extent of over 28% in one hour at 100 bar and 60 °C. Full article