Search Results (519)

Given the urgent need to decarbonize the global energy system, green hydrogen has emerged as a key alternative in the transition to renewables. However, its production via electrolysis demands high water quality and raises environmental concerns, particularly regarding reject water discharge. This study employs an experimental and analytical approach to define optimal water characteristics for electrolysis, focusing on conductivity as a key parameter. A pilot water treatment plant with reverse osmosis and electrodeionization (EDI) was designed to simulate industrial-scale pretreatment. Twenty water samples from diverse natural sources (surface and groundwater) were tested, selected for geographical and geological variability. A predictive algorithm was developed and validated to estimate useful versus reject water based on input quality. Three conductivity-based categories were defined: optimal (0–410 µS/cm), moderate (411–900 µS/cm), and restricted (>900 µS/cm). Results show that water quality significantly affects process efficiency, energy use, waste generation, and operating costs. This work offers a technical and regulatory framework for assessing potential sites for green hydrogen plants, recommending avoidance of high-conductivity sources. It also underscores the current regulatory gap regarding reject water treatment, stressing the need for clear environmental guidelines to ensure project sustainability. Full article

This study presents preliminary findings from an experimental campaign conducted on a pilot-scale green hydrogen production plant powered by a photovoltaic (PV) system. The integrated setup, implemented at the University “Mediterranea” of Reggio Calabria, includes renewable energy generation, hydrogen production via electrolysis, on-site storage, and reconversion through fuel cells. The investigation assessed system performance under different configurations (on-grid and selective stand-alone modes), focusing on key operational phases such as inerting, purging, pressurization, hydrogen generation, and depressurization. Results indicate a strong linear correlation between the electrolyser’s power setpoint and the pressure rise rate, with a maximum gradient of 0.236 bar/min observed at 75% power input. The system demonstrated robust and stable operation, efficient control of shutdown sequences, and effective integration with PV input. These outcomes support the technical feasibility of small-scale hydrogen systems driven by renewables and offer valuable reference data for calibration models and future optimization strategies. Full article

Fenton oxidation can contribute to meeting effluent standards for COD in actual wastewater treatment plant effluents. However, Fenton oxidation is prone to produce iron sludge waste. The application of heterogeneous Fenton-like systems based on Fenton iron mud carbon in wastewater treatment plants is essential for Fenton iron mud reduction and recycling. In this study, a Fenton iron mud carbon catalyst/Ferrate salts/H₂O₂ (FSC/Fe(VI)/H₂O₂) system was developed to remove chemical oxygen demand (COD) from secondary effluents at the pilot scale. The results showed that the FSC/Fe(VI)/H₂O₂ system exhibited excellent COD removal performance with a removal rate of 57% under slightly neutral conditions in laboratory experiments. In addition, the effluent COD was stabilized below 40 mg·L⁻¹ for 65 days at the pilot scale. Fe(IV) and ¹O₂ were confirmed to be the main active species in the degradation process through electron paramagnetic resonance (EPR) and quenching experiments. C=O, O-C=O, N sites and Fe⁰ were responsible for the generation of Fe(IV) and ¹O₂ in the FSC/Fe(VI)/H₂O₂ system. Furthermore, the cost per ton of water treated by the pilot-scale FSC/Fe(VI)/H₂O₂ system was calculated to be only 0.6209 USD/t, further confirming the application potential of the FSC/Fe(VI)/H₂O₂ system. This study promotes the engineering application of heterogeneous Fenton-like systems for water treatment. Full article

This study introduces Edible Streets as a distinct and scalable model of community-led urban food growing, specifically investigating the drivers and barriers to the initiative. Unlike traditional urban food-growing initiatives, Edible Streets explores the integration of edible plants into street verges and footpaths with direct community involvement of the people who live/work in a street. This study contributes new knowledge by evaluating Edible Streets through the COM-B model of behavioural change, through policy and governance in addition to behaviour change, and by developing practical frameworks to facilitate its implementation. Focusing on Oxford, the research engaged residents through 17 in-person interviews and 18 online surveys, alongside a stakeholder workshop with 21 policymakers, community leaders, and NGO representatives. Findings revealed strong motivation for Edible Streets, driven by values of sustainability, community resilience, and improved well-being. However, capability barriers, including knowledge gaps in gardening, land-use policies, and food preservation, as well as opportunity constraints related to land access, water availability, and environmental challenges, hindered participation. To address these, a How-to Guide was developed, and a pilot Edible Street project was launched. Future steps include establishing a licensing application model to facilitate urban food growing and conducting a Post-Use Evaluation and Impact Study. Nationally, this model could support Right to Grow policies, while globally, it aligns with climate resilience and food security goals. Locally grown food enhances biodiversity, reduces carbon footprints, and strengthens social cohesion. By tackling key barriers and scaling solutions, this study provides actionable insights for policymakers and practitioners to create resilient, equitable urban food systems. Full article

This work deals with the catalytic steam reforming of raw syngas to increase the efficiency of coupling gasification with downstream processes (such as fuel cells and catalytic chemical syntheses) by producing high-temperature, ready-to-use syngas without cooling it for cleaning and conditioning. Such a combination is considered a key point for the future exploitation of syngas produced by steam gasification of biogenic solid fuel. The design and construction of an integrated gasification and gas conditioning system were proposed approximately 20 years ago; however, they still require further in-depth study for practical applications. A 3D model of the freeboard of a pilot-scale, fluidized bed gasification plant equipped with catalytic ceramic candles was used to investigate the optimal operating conditions for in situ syngas upgrading. The global kinetic parameters for methane and tar reforming reactions were determined experimentally. A fluidized bed gasification reactor (~5 kWth) equipped with a 45 cm long segment of a fully commercial filter candle in its freeboard was used for a series of tests at different temperatures. Using a computational fluid dynamics (CFD) description, the relevant parameters for apparent kinetic equations were obtained in the frame of a first-order reaction model to describe the steam reforming of key tar species. As a further step, a CFD model of the freeboard of a 100 kWth gasification plant, equipped with six catalytic ceramic candles, was developed in ANSYS FLUENT^®. The composition of the syngas input into the gasifier freeboard was obtained from experimental results based on the pilot-scale plant. Simulations showed tar catalytic conversions of 80% for toluene and 41% for naphthalene, still insufficient compared to the threshold limits required for operating solid oxide fuel cells (SOFCs). An overly low freeboard temperature level was identified as the bottleneck for enhancing gas catalytic conversions, so further simulations were performed by injecting an auxiliary stream of O₂/steam (50/50 wt.%) through a series of nozzles at different heights. The best simulation results were obtained when the O₂/steam stream was fed entirely at the bottom of the freeboard, achieving temperatures high enough to achieve a tar content below the safe operating conditions for SOFCs, with minimal loss of hydrogen content or LHV in the fuel gas. Full article

Reducing meat consumption is a key strategy to mitigate environmental impact, lower the incidence of diet-related diseases, and promote sustainable food production. In response, the plant-based food market has grown significantly, motivated by demand for meat-like products. This study aimed to develop a meatless alternative to deli ham (MAD) free of chemical additives, adhering to clean label principles. A commercially available MAD product (Target MAD) was used as a benchmark. Based on its analysis, clean-label laboratory (Optimized CL formulation) and pilot-scale (CL MAD) prototypes were developed. These were evaluated for texture, rheology, color, sensory attributes, and physicochemical properties. The CL MAD demonstrated similar firmness to the Target MAD, while being 17% more cohesive and 50% less adhesive. Its mechanical spectra showed typical weak gel behavior, with G′ higher than G″. Color analysis indicated that the CL MAD was darker and less pink than the Target MAD. Nutritionally, it provided higher protein and lower fat content. Overall, this study successfully developed a clean-label meat-free alternative to deli ham that matches commercial textural standards while offering improved nutritional quality and eliminating chemical additives, meeting growing consumer demand for healthier and more sustainable foods. Full article

This study investigates an innovative soil washing process designed to remediate arsenic (As) contamination in sulfuric acid (H₂SO₄) plant soil by using discarded H₂SO₄ solution in situ. The pilot-scale process comprises five key steps: screening and rinsing of oversized sand, washing the soil with H₂SO₄, phase separation, recycling the washing solution, and water recovery. This research explored the optimal washing parameters for the process and further researched the reuse of the H₂SO₄ solution across multiple batches. The pH of the washing solution, critical at a threshold of 6.5, was identified as a key factor for effective recycling. Approximately 75% of the H₂SO₄ solution was successfully recycled. In terms of economic analysis, the total operational cost of the soil washing process was significantly lower than in previous studies. Overall, these findings demonstrate the feasibility of using discarded H₂SO₄ as a washing agent for As-contaminated soil. The integration of automated pH-based monitoring technology streamlines the washing process, providing a cost-effective and effective As removal remediation strategy, making it a viable option for large-scale applications in soil remediation. Full article

Industrial wastewater management remains a critical barrier to achieving Sustainable Development Goal 6 (SDG 6) in many developing countries, where regulatory frameworks exist but affordable and scalable treatment solutions are lacking. In Pakistan, the textile sector is a leading polluter, with untreated effluents routinely discharged into rivers and agricultural lands despite stringent National Environmental Quality Standards (NEQS). This study presents a pilot-scale case from Faisalabad’s Khurrianwala industrial zone, where a decentralized, nature-based bioreactor was piloted to bridge the gap between policy and practice. The system integrates four treatment stages—anaerobic digestion (AD), floating treatment wetland (FTW), constructed wetland (CW), and sand filtration (SF)—and was further intensified via nutrient amendment, aeration, and bioaugmentation with three locally isolated bacterial strains (Acinetobacter junii NT-15, Pseudomonas indoloxydans NT-38, and Rhodococcus sp. NT-39). The fully intensified configuration achieved substantial reductions in total dissolved solids (TDS) (46%), total suspended solids (TSS) (51%), chemical oxygen demand (COD) (91%), biochemical oxygen demand (BOD) (94%), nutrients, nitrogen (N), and phosphorus (P) (86%), sulfate (26%), and chloride (41%). It also removed 95% iron (Fe), 87% cadmium (Cd), 57% lead (Pb), and 50% copper (Cu) from the effluent. The bacterial inoculants persist in the system and colonize the plant roots, contributing to stable bioremediation. The treated effluent met the national environmental quality standards (NEQS) discharge limits, confirming the system’s regulatory and ecological viability. This case study demonstrates how nature-based systems, when scientifically intensified, can deliver high-performance wastewater treatment in industrial zones with limited infrastructure—offering a replicable model for sustainable, SDG-aligned pollution control in the Global South. Full article

The global energy sector is aiming to substantially reduce CO₂ emissions to meet the UN climate goals. Among the proposed strategies, underground storage solutions such as radioactive disposal, CO₂, NH₃, and underground H₂ storage (UHS) have emerged as promising options for mitigating anthropogenic emissions. These approaches require rigorous research and development (R&D), often involving laboratory-scale experiments to establish their feasibility before being scaled up to pilot plant operations. Microorganisms, which are ubiquitous in laboratory environments, can significantly influence geochemical reactions under variable experimental conditions of porous media and a salt cavern. We have selected a consortium composed of Bacillus sp., Enterobacter sp., and Cronobacter sp. bacteria, which are typically present in the laboratory environment. These microorganisms can contaminate the rock sample and develop experimental artifacts in UHS experiments. Hence, it is pivotal to sterilize the rock prior to conduct experimental research related to effects of microorganisms in the porous media and the salt cavern for the investigation of UHS. This study investigated the efficacy of various disinfection and sterilization methods, including ultraviolet irradiation, autoclaving, oven heating, ethanol treatments, and gamma irradiation, in removing the microorganisms from silica sand. Additionally, the consideration of their effects on mineral properties are reviewed. A total of 567 vials, each filled with 9 mL of acid-producing bacteria (APB) media were used to test killing efficacy of the cleaning methods. We conducted serial dilutions up to 10⁻⁸ and repeated them three times to determine whether any deviation occurred. Our findings revealed that gamma irradiation and autoclaving were the most effective techniques for eradicating microbial contaminants, achieving sterilization without significantly altering the mineral characteristics. These findings underscore the necessity of robust cleaning protocols in hydrogeochemical research to ensure reliable, reproducible data, particularly in future studies where microbial contamination could induce artifacts in laboratory research. Full article

This work presents the characterization of a large-scale pilot plant for nitric acid production that employs atmospheric-pressure plasma in a closed-loop configuration. The primary objective here is to evaluate the scientific and practical feasibility of using high-power Cerawave™ plasma torch technology, manufactured by Radom Corporation, to enhance the rate of nitric acid production of plasma-assisted nitrogen fixation systems, while achieving specific energy consumption (SEC) comparable to that of smaller-scale setups reported in the literature. We provide a comprehensive overview of the components of the pilot plant, its operational strategy, and the analytical models underlying its processes. Preliminary system optimization results are discussed alongside the outcomes from a controlled batch run. After 30.9 h of operation at 50 kW plasma power, the system produced 198.9 L of nitric acid with a concentration of 28.6% by weight, corresponding to overall SEC of approximately 5.3 MJ/mol. This SEC could be improved to 3.7 MJ/mol using absorption columns with greater than 90% absorption efficiency. Additionally, around 60% of the plasma power was recovered as usable process heat via a heat exchanger. These results demonstrate that plasma-based nitrogen fixation is scientifically and technically viable at higher production scales while maintaining competitive specific energy consumption using microwave plasma. Full article

The objective of this study was to investigate the chemical composition of the obtained products, as well as the antioxidant activity and bio-stimulant potential of the liquid fractions. The biomass was subjected to pyrolysis in a pilot-scale reactor, followed by distillation of the pyroligneous liquid to separate volatile compounds and enrich bioactive fractions. The samples were analysed by FTIR, TGA/DTG, and GC-MS. Antioxidant activities were assessed through DPPH, FRAP, and total phenolic content assays, while the bio-stimulant potential was evaluated through germination and growth tests of lettuce and arugula seeds. The results showed that the distilled fraction had lower acidity, greater chemical stability, and high antioxidant activity, with the presence of industrially valuable compounds such as methoxylated phenols and furfural. Furthermore, application of the distilled liquid at 0.1% concentration stimulated early seedling development—especially in arugula—while higher concentrations demonstrated inhibitory effects. These findings show that distillation of pyroligneous liquid is an effective strategy to enhance its bioactive properties, enabling its use as a natural antioxidant and plant bio-stimulant. Full article

Softwood bark and twigs represent by-products of forest supply chains rich in extractable bioactive compounds. This study aimed at evaluating the bioactive molecules of hydrodynamic cavitation (HC) based extracts of bark and twigs from different conifer plants and exploring their antioxidant capacity. Samples of Picea abies twigs (RAR) and bark (CAR) and Abies alba twigs (SFT) underwent extraction using a pilot-scale Venturi reactor HC device. The freeze-dried extracts were characterized for the antioxidant capacity, through both in vitro and ex vivo assays, the antimicrobial activity, and the content of phenolics and free amino acids by UHPLC-ESI-MS/MS. HC-based aqueous extracts were obtained quickly and with low energy consumption. We found 10 phenolic acids, nine flavonols, three flavan-3-ols, five flavanones, three procyanidins, two stilbenoids, and 10 other phenolic compounds. Moreover, eight essential and seven dispensable amino acids were found. The principal component analysis showed clear discrimination among the three extracts. The CAR extract showed antimicrobial activity. The SFT extract showed the higher anthocyanins content and antioxidant activity, both through in vitro and ex vivo methods. These preliminary results confirm that by-products of Picea abies and Abies alba are rich in bioactive compounds and antioxidant activities, suggesting potential applications in the nutraceutical and pharmaceutical fields. Full article

An integrated process scheme is developed for valorizing filtered liquid digestates (FLD) from an industrial anaerobic digestion (AD) plant treating dairy-processing effluents with relatively low nutrient concentrations. The process scheme involves FLD treatment by nanofiltration (NF) membranes, followed by struvite recovery from the NF-retentate. An NF pilot unit (designed for this purpose) is combined with a state-of-the-art NF/RO process simulator. Validation of simulator results with pilot data enables reliable predictions required for scaling up NF systems. The NF permeate meets the standards for restricted irrigation and/or reuse. Considering the significant nutrient concentrations in the NF retentate (i.e., ~500 mg/L NH4-N, ~230 mg/L PO4-P), struvite recovery/precipitation is investigated, including determination of near-optimal processing conditions. Maximum removal of nutrients, through production of struvite-rich precipitate, is obtained at a molar ratio of NH₄:Mg:PO₄ = 1:1.5:1.5 and pH = 10 in the treated stream, attained through the addition of Κ₂HPO₄, ΜgCl₂·6H₂O, and NaOH. Furthermore, almost complete struvite precipitation is achieved within ~30 min, whereas precipitate/solid drying at modest/ambient temperature is appropriate to avoid struvite degradation. Under the aforementioned conditions, a significant amount of dry precipitate is obtained, i.e., ~12 g dry mass per L of treated retentate, including crystalline struvite. The approach taken and the obtained positive results provide a firm basis for further development of this integrated process scheme towards sustainable large-scale applications. Full article

This study presents the development of the Plant Perception Scale (PPS), a multidimensional tool designed to assess high school students’ awareness of the ecological, utilitarian, and cultural significance of plants. Positioned within the broader goal of Education for Sustainable Development (ESD), the scale aims to identify perception gaps that may hinder students’ engagement with biodiversity and sustainability. Following a rigorous development process—including item generation, expert review, pilot testing, and psychometric validation—the final 21-item scale revealed a three-factor structure: Ecological Awareness and Sustainability Perception (12 items), Utility-Oriented Plant Perception (5 items), and Cultural and Aesthetic Perception (4 items). Exploratory Factor Analysis confirmed data suitability (KMO = 0.920; Bartlett’s χ²(210) = 2245.215, p < 0.001). Confirmatory Factor Analysis supported the structure with strong fit indices (χ²/df = 2.204; CFI = 0.949; RMSEA = 0.055). Internal consistency was high (Cronbach’s α = 0.88 for the total scale; factor α values ranged from 0.823 to 0.939). The PPS contributes to sustainable education by offering a reliable framework to evaluate plant-related awareness among adolescents and can serve as a diagnostic and pedagogical tool to guide curriculum development and educational interventions in support of the SDGs. Full article

This paper presents a novel small-scale system for drinking water treatment from surface waters, designed to rely on gravity as the only source of energy driving the treatment process. The pilot-scale setup, designed for a flow rate of 0.5 L/s, was tested at the Cornell University Water Filtration Plant (CWFP) for a total period of 5 months of operation. The experiments evaluated the influence of selected process parameters on system performance. The identified best operation practices were used to complete a comparative study against CWFP’s full-scale treatment process and to conduct a performance assessment in the context of various legislative landscapes. The objective of the work was to determine both the advantages and disadvantages of the proposed technology over established solutions. Over the study period, the average turbidity of the produced water was equal to 0.54 NTU. The pilot complied with the United States Environmental Protection Agency (US EPA) turbidity standard of <0.3 NTU 47.1% of the time and <1 NTU for 89.9% of the time, thus falling short of the standard of <0.3 NTU 95% of the time and <1 NTU 100% of the time. For 99.5% of the time, it complied with the World Health Organization turbidity guideline of <5 NTU for chlorination treatment. The benchmark conventional system outperformed the tested prototype, complying with the US EPA standards for the entire duration of the study. The tested process also generated a waste stream, which accounted on average for more than 10% of the total raw water volume. Full article