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This study investigates the impact of advanced electricity outage announcements on the operational efficiency of small and medium enterprises (SMEs), in Egypt, using profitability as a key performance indicator. Leveraging data from “Transition to Clean Energy Enterprise Survey” and applying the inverse probability-weighted regression adjustment (IPWRA) method to address selection bias, we estimate how outage predictability influences firm outcomes. We find that SMEs receiving advance notice of power disruptions are significantly more likely to achieve higher profitability compared to those without such information. The benefits are most evident among larger firms and sectors such as transportation, financial services, and accommodation, where operational planning is critical. While the policy partially offsets losses from outages, firms in areas with frequent blackouts still face substantial profitability challenges, highlighting the limits of transparency alone. Our findings emphasize that advance announcements enhance SME resilience by enabling adaptive measures, but long-term solutions require complementary infrastructure investments in high-risk regions. The study advocates for policy frameworks centered on transparency and rational expectations, demonstrating how proactive communication in public services can bolster economic resilience amid global uncertainties. These insights are particularly relevant for developing economies seeking to balance immediate crisis management with sustainable energy infrastructure development.

The treatment of gaseous contaminants, such as hydrogen sulfide (H2S), is often carried out with adsorbent materials that are disposed of after saturation. The reuse of such materials promotes sustainability and the reduction in unnecessary waste. Granular activated carbon (GAC) is a well-known adsorbent used to capture gaseous H2S which can be reused. It is hypothesized that it can also concentrate contaminants for future treatment, thereby reducing secondary treatment costs. Cyclic adsorption/desorption experiments were completed with samples of GAC to investigate the feasibility of implementing the concept of repeated H2S adsorption/desorption in the construction of a pilot odor control device. A column filled with GAC was exposed to a stream of H2S gas and then heated to 500 °C to regenerate the carbon. The concentration of H2S at the inlet and outlet of the column was measured at regular intervals. Three samples of GAC had an average adsorption efficiency of 82% over the course of three cycles and were regenerated to 70% of initial adsorptive capacity after one cycle, and 60% after two cycles. These results indicate that after being saturated with H2S, GAC can be regenerated at high temperatures, evidence that H2S may become concentrated during the process. Additional characterization experiments confirmed that the sulfur content of the carbon increased after adsorption and decreased after thermal regeneration. The procedures demonstrated in this experiment were further utilized with a pilot device designed to provide a low-cost method for reducing odors in landfill gas.

This review critically examines state-of-the-art numerical methodologies for the simulation of wind turbines, offering a rigorous exploration of their theoretical foundations, practical implementations, and comparative performance. It begins by establishing a contextual framework through the classification of wind turbines, with particular focus on vertical axis configurations and emerging hybrid designs. The core of the study delves into advanced computational techniques encompassing computational fluid dynamics (CFD), finite element analysis (FEA), and fully coupled CFD-FEA frameworks used to resolve aerodynamic, structural, and fluid–structure interaction phenomena with high fidelity. The paper systematically analyzes turbulence modeling strategies, from industry-standard Reynolds-averaged Navier–Stokes (RANS) models to high-resolution large eddy simulation (LES) and hybrid detached eddy simulation (DES) approaches, evaluating their capabilities in capturing unsteady flow structures, vortex dynamics, and wake interactions. Additionally, reduced-order models such as the actuator line method (ALM) and actuator disk method (ADM) are assessed for their scalability in large wind farm simulations. Detailed discussions cover geometry generation, mesh refinement techniques, solver configuration, and post-processing analytics, offering best practices for ensuring numerical stability, accuracy, and validation. Through a comparative synthesis of these methods, the paper provides deep insights into their trade-offs in terms of computational cost, physical realism, and practical applicability, ultimately guiding the selection and optimization of simulation strategies for advanced wind energy system design and performance evaluation.

Harmful algal blooms (HABs) are a primary environmental concern, threatening freshwater ecosystems and public health and causing economic damages in the billions of dollars annually. These blooms, predominantly driven by phytoplankton species like cyanobacteria, thrive in nutrient-rich, warm, and low-wind environments. Because of the adverse impacts of HABs, this review examines various control methods, focusing on biological strategies as sustainable solutions. While effective in disrupting algal populations, traditional chemical and physical interventions carry ecological risks and can be resource-intensive. Biological control methods, including biomanipulation and using algicidal microorganisms such as Streptococcus thermophiles, Myxobacteria, and Lopharia spadicea, emerge as eco-friendly alternatives offering long-term benefits. Additionally, barley and rice straw application has demonstrated efficacy in curbing HAB growth. These biological approaches work by inhibiting algal proliferation, disrupting cellular structures, and fostering algal cell aggregation. Despite their advantages over conventional methods, biological controls face challenges, including intricate ecological interactions. This article delves into the latest biological techniques aimed at eradicating HABs, intending to diminish their frequency and reduce toxin levels in aquatic environments. While most research to date has been confined to laboratory settings, scaling these methods to field applications presents hurdles due to the variability and complexity of natural ecosystems. The review underscores the need for further research and development in this critical area of environmental science.

Hydrogen sulfide (H2S) is a naturally occurring, highly toxic gas that is formed from the decomposition of sulfur compounds. H2S is a common source of concrete and metal corrosion that results in huge economic losses in wastewater collection and treatment plants. Hence, it is necessary to analyze H2S generation and emission. H2S concentrations were measured at the Al-Saad wastewater treatment plant in the United Arab Emirates. Wastewater samples were collected, and water quality parameters were characterized in the laboratory. Simultaneously, flow characteristics, humidity, headspace airflow, and temperature were measured onsite. A neural network model to predict H2S emissions was formulated using significant parameters. It was observed that flowrate, velocity, sulfate, and total sulfur had a similar cyclic pattern throughout the sampling events. The temperature, humidity, total sulfur, and depth of wastewater were identified as the most important parameters influencing H2S emissions through correlation analysis. The neural model validation and testing had an R value of 0.9. The training had an R value of 0.8. The model provided an accuracy of 80% for the prediction of H2S concentration in wastewater treatment plants. The accuracy can be improved by increasing the data. The model is limited to its applicability in the prediction of H2S emissions under conditions similar to the inlet of a wastewater treatment plant.

Global climate change due to heavy industrial carbon dioxide (CO 2 ) emissions has become one of the most significant environmental concerns. Mineral carbonation of alkaline wastes into valuable products is a promising CO 2 capture, storage, and utilization technique. This study investigated the direct mineral carbonation of carbide slag, a byproduct of acetylene production, in both dry and wet phases under moderate conditions (≤ 120 °C, ≤ 1 MPa) in a fixed bed reactor. Mineral carbonation of carbide slag was validated by online gas chromatography, thermogravimetric analysis, and microstructure characterization of the carbonated products. Moreover, the effects of operational parameters such as temperature, pressure, gas–solid ratio, superficial gas velocity, particle size, and initial gas concentration on the carbonation reaction were studied. The results show that wet-phase carbonation at a liquid‒solid ratio of 0.2 achieves a maximum carbonation efficiency of 37% and a CO 2 capture capacity of 4.6 mol CO 2 kg −1 , outperforming the dry phase under ambient conditions. Humidity in the inlet gas stream and a higher reaction pressure improved carbonation in both phases. A maximum carbonation efficiency of 97% was observed, with a CO 2 capture capacity of 12.2 mol CO 2 kg −1 in the wet phase of mineral carbonation at 1 MPa pressure. Microstructural analyses revealed a significant formation of calcium carbonate in the carbonated samples. This study highlights the potential of carbide slag for effective CO 2 capture through mineral carbonation, offering an environmentally friendly and scalable solution for reducing greenhouse gas emissions.

The pressure on the environment from wastewater has been increasing in line with industrialization and urbanization, thus calling for better and eco-friendly solutions for wastewater treatment. Extremophilic microorganisms, which can grow in extreme conditions including high salinity, acidity, and temperature, can be applied in wastewater bioremediation. This review assesses the various functions of extremophiles, halophiles, thermophiles, alkaliphiles, and acidophiles in the treatment of organic and inorganic pollutants. They are capable of catabolizing a wide range of hazardous chemicals, such as polycyclic aromatic hydrocarbons, phenolic compounds, and heavy metals. Moreover, extremophilic microalgae, like Galdieria sulphuraria, have been effective in nutrient removal, biosorption of heavy metals, and pollutant conversion into valuable biomass. This dual-functioning, therefore, helps not only in wastewater treatment but also in the production of biofuel and biofertilizer, making the process cost-effective. The use of extremophiles in biofilm reactors improves pollutant removal, with less energy input. Extremophilic microorganisms can, therefore, be used to revolutionize wastewater management by providing green solutions to current treatment approaches. This review discusses the existing drawbacks of wastewater treatment along with the additional requirements needed to enhance the capability of bioremediation and potential future research.

The harmful environmental impacts of fossil fuel combustion, particularly greenhouse gas (GHG) emissions, have driven global interest in developing sustainable biodiesel alternatives. Pakistan imports 294.46 million tons of high-speed diesel (HSD) annually, costing approximately USD 140.237 million. A 10% biodiesel blend could save 29.446 million tons of HSD and USD 14.023 million annually. Fish waste, a significant byproduct of Pakistan’s fishing industry, offers a promising feedstock for biodiesel production. This study explores its conversion into biodiesel and evaluates performance in diesel engines, supporting sustainability and circular economy goals. This study produced fish waste biodiesel through two-step transesterification reactions, achieving a 68% conversion yield. The biodiesel exhibited properties within ASTM D6751 standards, with a calorific value of 40.47 MJ/kg and a cetane number of 55.92. Engine performance and emission tests on LOMBARDINI 15LD225 diesel engines showed significant CO emission reductions with B10 and B20 blends compared to conventional diesel. Simulation using Ricardo Wave software 2019.1 demonstrated a 90% model accuracy for predicting CO emissions. The findings highlight the viability of fish waste-derived biodiesel as a cleaner, renewable alternative to fossil diesel, supporting sustainability and circular economy goals.

The treatment efficiency of Chlorella sorokiniana and Scenedesmus species, immobilized in sodium alginate, was evaluated for removing nitrate from groundwater. The experiments were performed initially in batch mode and the best-performing conditions were replicated in sequencing batch reactor mode. S. sp. showed a higher nitrate uptake in short term than C. sorokiniana. Immobilized S. sp. and C. sorokiniana cells showed 90% nitrate removal in 9 and 12 days, respectively. The optimal ratio of algal beads/water was found to be 12.5% (v:v). Comparatively, suspended S. sp. cells were able to remove only up to 35% of nitrate in 8 days. Alginate immobilized S. sp. beads were capable of uptaking nitrate for 100 consecutive days in sequencing batch reactor mode. When tested in actual groundwater, 90% of nitrate was eliminated in 2 days without need for any additional carbon source. Immobilized algal beads can be a low-cost alternative technique to remove nitrate from groundwater as they are water-insoluble, non-toxic, easy to harvest, and offer high removal efficiency.

A coagulation treatment is a separation technology widely used in industries as a pre-treatment step to remove the dissolved organic matter in wastewater. However, the type of coagulant, the optimized dose, and the treatment cost associated with various commercially employed coagulants must be investigated for the treatment of oil and gas produced water. In this study, five widely employed coagulants—ferric chloride, aluminum potassium sulphate, chitosan, sodium sulfide, and magnesium oxide—were tested for the treatment of actual complex oilfield-generated produced water. Water quality parameters such as the total suspended solids (TSS), total dissolved solids (TDS), turbidity, salinity, and pH were assessed for a better understanding of different coagulant activities against the produced water treatment. All the coagulants were efficient for the treatment of produced water. The findings of this study showed that ferric chloride led to the best removal of total solids (74.25%) of all water quality parameters, with treatment costs of USD 4 per m−3 of produced water. The results from this study contribute to the environmentally friendly, broader, and cost-effective application of a coagulation treatment to produced water.