Search Results (2,150)

The intensifying global challenges of environmental degradation, escalating energy demands, and unsustainable waste accumulation necessitate the exploration of alternative, high-value biomass resources. Algal biomass has emerged as a uniquely versatile and sustainable candidate, offering transformative potential across a broad range of industrial and environmental sectors. This review comprehensively evaluates the recent advancements and multidisciplinary applications of algae, with a strong emphasis on their distinctive chemical composition, bioactive compounds, and environmental adaptability. The novelty of this review lies in its integrative scope, which spans from algae cultivation, production, and trade to cutting-edge extraction technologies for bioactive constituents. Furthermore, the review presents a detailed exploration of algae’s functionality as a feedstock for biofuels, pharmaceuticals, sustainable agriculture, bioplastics, green chemistry, and water treatment, positioning it as a cornerstone in the development of the blue economy. By critically analyzing both conventional and innovative applications, this work contributes to a deeper understanding of algae’s strategic role in shaping a sustainable and resilient bioeconomy. Full article

Pharmaceutical and microbial pollution in urban rivers is an emerging concern, particularly in developing regions with limited wastewater treatment capacity, posing risks to human health and ecosystems. This study evaluated the risk profiles of selected pharmaceutical compounds and bacterial indicators in the Sand River, South Africa, and computed their ecological risks, antimicrobial resistance (AMR), and human health risk assessment. Surface water samples were collected from three sites during the wet season and analyzed for target antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) using High-Performance Liquid Chromatography (HPLC) with a photodiode array (PDA) detector, while total coliforms (TCs) and Escherichia coli (E. coli) were enumerated using the Colilert system. Ciprofloxacin, sulfamethoxazole, and erythromycin were the most abundant pharmaceuticals, with maximum concentrations of 2.50 µg/L, 2.76 µg/L, and 2.53 µg/L, respectively. TC and E. coli levels exceeded regulatory thresholds, indicating severe microbial contamination. Risk quotient analysis identified ciprofloxacin, erythromycin, and trimethoprim as high-risk compounds for potential resistance selection (RQ ≥ 1), while ciprofloxacin and erythromycin posed significant ecological risks to fish. Although non-carcinogenic health risk assessment remained below concern (HI < 1), children showed higher exposure levels. These findings underscore the urgent need for improved pharmaceutical waste management and wastewater treatment infrastructure. Full article

This study investigates the occurrence, distribution, and environmental implications of polymer-derived additives, including per- and polyfluoroalkyl substances (PFAS), in aquatic systems impacted by the Brånåsen legacy landfill in Norway. Water samples were collected from landfill leachate and from seven locations along the Nitelva River to evaluate both point-source contamination and downstream transport processes. UHPLC–HRMS and GC–MS/MS suspect screening analyses provided tentative evidence for dimethacrylate-related compounds, including features putatively assigned to DEGDMA and TEGDMA-related compounds, potentially associated with polymer degradation processes. Selected PFAS were instead quantified by targeted LC–MS/MS, with PFOS, PFOA, PFHxS, and PFHxA exhibiting the highest concentrations at the landfill tributary, reaching maximum concentrations of up to 780 ng L⁻¹, and decreasing downstream consistently with dilution and hydrological mixing, while remaining detectable throughout the river reach. Temporal variation indicated short-term hydrological influences on contaminant mobility. The study highlights the role of legacy landfills as persistent sources of emerging pollutants in freshwater environments. These findings underscore the need for improved monitoring strategies and advanced treatment measures to address complex contaminant mixtures originating from historical waste disposal activities. Full article

The growth in açaí consumption and exports has increased waste generation, particularly from the seed, which accounts for approximately 85% of the fruit mass and is frequently discarded improperly, causing adverse environmental impacts. In this context, the valorization of açaí seeds as a raw material represents a promising and environmentally sustainable alternative. Recent studies indicate that the chemical composition of açaí seeds, characterized by high fiber content and antioxidant compounds, underlies bioactive properties with potential applications across multiple industrial sectors. Therefore, this review aims to provide an overview of the composition and industrial applications of açaí seeds, while identifying current gaps and challenges. Available evidence suggests that incorporating açaí seed flour or extracts into food formulations is promising, although the observed effects are concentration-dependent. In addition, seed-derived extracts have demonstrated biological activities associated with potential health benefits. Furthermore, açaí seeds have potential applications as biochar for soil remediation and as adsorbents in water and wastewater treatment. However, the use of this by-product in packaging materials and in the energy sector still requires further investigation to achieve industrial-scale feasibility. Overall, the valorization of açaí seeds supports more sustainable industrial practices and aligns with circular economy principles. Full article

This study evaluated breast meat quality of broiler chickens following dietary inclusion of full-fat Black soldier fly (Hermetia illucens) larvae (BSFL) sourced from three food-waste production sites in a nutritionally balanced diet. Broilers were fed diets containing 0%, 3%, 6%, or 9% BSFL sourced from 3 different facilities in a 3 × 4 factorial design. At 42 days of age, breast meat samples were collected for evaluation of physicochemical traits, chemical composition, amino acid, and fatty acid profiles. Inclusion of dietary BSFL had no adverse effects on key meat quality parameters, including water-holding capacity, pH, color, cooking loss, or shear force. Breast meat protein content increased significantly in broilers fed the 9% BSFL diet compared with the control, while essential amino acid composition remained unchanged across treatments. In contrast, BSFL inclusion substantially modified the fat profile of breast meat, characterized by enrichment of short- and medium-chain saturated fatty acids, increased eicosapentaenoic acid, reduced ω-6 polyunsaturated fatty acids, and an improved ω-3/ω-6 ratio. These results demonstrate that food-waste-derived full-fat BSFL can be incorporated into broiler diets at levels up to 9% without compromising breast meat quality, while enhancing its nutritional fat profile and protein content. Full article

This study explores the real-time aging of a 15-year-old uncalcined kaolinite-based geopolymer (UKG). The significance of this research lies in the fact that uncalcined kaolinite-based geopolymer is a relatively new material tailored for diverse applications, including construction, water treatment, and waste stabilization. While some studies have investigated its durability through accelerated tests, observing its aging over 15 years is essential for its commercial use and field deployment. The specimens were prepared from kaolinite, silica sand, sodium hydroxide, and water. The mixture was molded, compacted, and cured at 80 °C for 24 h to produce a stable geopolymer. Some samples were stored under ambient conditions, while others were immersed; both groups were left for 15 years. After this period, tests evaluated their mechanical, physical, and microstructural properties using XRD, EDS, and SEM. The samples stored under ambient conditions exhibited properties comparable to those of the unaged specimens. In contrast, the immersed samples were unstable, experienced mass loss, showed a sharp decline in strength, and displayed significant microstructural and phase changes. This study suggests adding an extra curing step, such as steaming (hydrothermal) or immersion in alkaline solutions, to enhance the long-term stability of geopolymer binder under immersion conditions. Full article

This study explores the application of a bioflocculant derived from poultry eggshell waste for the removal of Chlorella spp. and related contaminants from agricultural wastewater using a statistically guided experimental design. In accordance with circular bioeconomy principles, eggshell residues were repurposed as a low-cost and sustainable biomaterial for water treatment. Chlorella spp. was selected as the target microalga due to its rapid proliferation, tolerance to eutrophic environments, and frequent presence in agricultural effluents. A two-level factorial design with center points was applied to evaluate the individual and interactive effects of key operational parameters, including pH, temperature, initial biomass concentration, and bioflocculant dosage. The highest biomass removal efficiency (94%) was achieved at pH 10, a temperature of 18.5 °C, a bioflocculant dose of 100 mg L⁻¹, and an initial biomass concentration of approximately 3.76 × 10⁷ cells mL⁻¹, with a contact time of 360 min. Under these optimized conditions, notable reductions were also observed in chemical oxygen demand (78%), nitrates (87%), phosphates (21%), and coliform bacteria (99.6%). The developed regression model exhibited strong predictive capability (R² = 0.97), indicating high reproducibility within the investigated experimental conditions. Overall, the findings suggest that eggshell-derived bioflocculants may represent a promising alternative to conventional chemical flocculants for agricultural wastewater treatment. High removal efficiency was achieved at relatively low dosages under operational conditions, supporting the potential of this approach for improving microalgae harvesting and the wastewater treatment processes. Full article

The linear economic model continues to drive multidimensional environmental problems, as it generates large volumes of plastic waste, as well as agricultural by-products, such as coconut husks. On the other hand, the maritime industry still relies on conventional materials such as wood, steel, and fibre-reinforced plastics, which have several usage challenges, including corrosion, toxicity, and difficulties associated with end-of-life management. These issues point to the need for more sustainable material options. This review examines the potential of combining coconut fibre (coir) with recycled plastics to produce a functional material for use in the maritime sector. The material is designed to add value to waste streams by providing a practical approach to reducing dependence on conventional and less sustainable resources. The review discusses fibre treatments (alkali, silane, acetylation) and fabrication methods (compression moulding, extrusion) and evaluates their impact on mechanical performance and durability. The studies show that coir–plastic composites possess highly tuneable mechanical properties. Tensile strengths are reported to range from approximately 2.4 MPa for natural resin matrices to 78 MPa for polyester hybrids, while the flexural modulus can be increased by up to 99% compared to the neat polymer blend. Fibre treatments (e.g., alkali) and fabrication methods are crucial, as they have been shown to improve tensile and flexural strength by over 40% and impact strength by 150%. However, the composites produced still show vulnerability to water absorption, UV radiation, and biofouling, which could limit their application in marine environments. To this end, several issues require further study, including long-term field validation, enhanced understanding of material fatigue, and scalable manufacturing. Full article

This study presents the development of an eco-friendly brick for mining, a sustainable composite material manufactured from gold mine tailings and used cooking oil (UCO) through a thermal oxypolymerization process. Unlike conventional stabilization methods, which often require additional materials beyond tailings or have a high carbon footprint in their production, this approach uses oxypolymerization to transform these two waste products into novel building materials. The use of various percentages of UCO at different heating temperatures was evaluated to identify the optimal mixture, determining that a 9% UCO content and a 9 h cycle are key conditions for inducing fatty acid crosslinking. This logical relationship between heat treatment and dosage allows the organic binder to consolidate the mineral matrix, giving the material a compressive strength of 19.12 MPa and a flexural strength of 8.24 MPa, exceeding the thresholds of the NTE INEN 297 standard. The low water absorption (2.86%) is attributed to the densification of the matrix and the hydrophobic nature of the polymerized oil, indicators of its structural durability. This work is the first to use Ecuadorian tailings as the sole mineral aggregate, validating a high-efficiency, low-impact product for sustainable construction under the principles of the circular economy. Full article

The Peruvian anchoveta fishmeal industry generates wastewater (pumping water) during the transport of fish from boats to production plants. This study represents the first evaluation in Peru of Moringa oleifera (MOD) and chitosan as bio-coagulants specifically applied to the coagulation–flocculation treatment of pumping water, providing a direct comparative analysis against traditional ferric sulfate under identical experimental conditions. The effluent is characterized by an extreme turbidity of 5,683 NTU, total suspended solids (TSS) at 3359.3 mg/L, and oils and fats at 451.3 mg/L, and it was treated using optimized doses: 4.0 g/L for MOD and 0.2 g/L for chitosan. The results demonstrate that natural alternatives achieve turbidity removal exceeding 97.5%, matching the efficiency of inorganic salts. Notably, chitosan achieved 88.59% TSS removal with no significant statistical difference (p > 0.05 according to the Kruskal–Wallis test) from ferric sulfate, while MOD excelled in oil reduction (37.84%) compared with chitosan. Beyond treatment efficiency, this research fills a gap in circular economy data by identifying that the resulting sludge, containing >4% non-toxic nitrogen, is suitable for composting. These findings establish a new renewable benchmark for the Peruvian fishing industry’s transition toward sustainable, zero-waste water management. Full article

The foreseen implementation of the recast European Union Urban Wastewater Treatment Directive (EU) 2024/3019 will extend the previous regulation’s purpose to cover agglomerations from 1000 population equivalent upwards, and impose more stringent requirements on larger plants. Member States’ local authorities will be responsible for carrying out a range of organizational and infrastructural tasks, including the expansion of sewerage networks and the construction/modernization of wastewater treatment plants. This study presents an analysis aimed at assessing the readiness of small and medium-sized wastewater treatment plants in Poland to meet the new forthcoming requirements. The study examines the extent to which the present performance of small and medium-sized treatment plants in Poland complies with current regulations, and their readiness to comply with future environmental standards set by the new Directive. The structure of the national sewerage system is taken into account with the case study analysis of the present situation in the Opolskie Voivodeship. The novelty and methodological contribution of the study lies in bridging the regulatory analysis with local-scale operational data from selected facilities, as well as statistical data on the national wastewater treatment system published by Statistics Poland (GUS), linking local-scale WWTP performance with broader systemic conditions at the national level. Full article

The increasing share of renewable energy, such as solar and wind energy, in the energy mix implies a demand for sustainable energy storage systems for the mitigation of the intermittency of these energy sources. One option, therefore, is stationary batteries based on abundant sodium, stored in hard carbon (HC) anodes. In this work, following the sustainable by design principle, HCs were synthesized from cotton-based textile waste using three different thermochemical routes: hydrothermal carbonization (HTC) followed by pyrolysis under nitrogen atmosphere (HC-250-N), HTC followed by pyrolysis under a water vapor stream (HC-250-W), and direct pyrolysis (HC-direct-N). The impact of the synthesis method on the physicochemical properties and electrochemical performance of the HCs was thoroughly investigated. X-ray diffraction, Raman spectroscopy, electron microscopy, and gas adsorption analyses revealed that the HTC pre-treatment significantly enhanced the carbon content, microporosity, and degree of structural graphitic order. HC-250-N exhibited the highest graphitic character and more uniform microstructure, while HC-250-W showed the largest specific surface area and broader micropore distribution. Electrochemical evaluation in sodium-ion half-cells indicated that HC-250-N delivered the most balanced performance, with a reversible capacity of 335 mAh g⁻¹ and good cycling stability. These findings confirm the potential of textile waste-derived HCs as promising and sustainable anode materials for sodium-ion batteries and highlight the importance of tailoring synthesis parameters—such as HTC treatment and pyrolysis conditions—to optimize their structural and electrochemical properties. Full article

Increasing volumes of dye-containing wastewater generated by the textile industry have become a serious environmental issue, particularly in Indonesia, where textile production contributes substantially to industrial activity. Among synthetic dyes, methylene blue (MB) is widely used because of its low cost and high solubility in water; however, its persistence, toxicity, and potential carcinogenicity make its removal from wastewater highly important. Conventional treatment methods are often limited by incomplete degradation and secondary waste generation. In this study, iron oxide nanoparticles (IONPs) were synthesized through a green route using Psidium guajava leaf extract as both a reducing and stabilizing agent. Characterization by PSA, UV-Vis, SEM-EDX, and XRD confirmed the formation of magnetite-like iron oxide particles with sizes ranging from 209.2 to 291.4 nm. Photocatalytic experiments showed high MB degradation efficiency (94.7–99.0%) under UV irradiation, highlighting the potential of guava leaf-mediated IONPs as low-cost, sustainable photocatalysts for wastewater treatment. Full article

The growth of the global population has led to increased demand for agricultural products, resulting in greater agricultural waste production. One sustainable response to this challenge is using agricultural waste as raw material in building materials. This study examines the potential for partial replacement of natural aggregates in concrete with agricultural waste from typical Mediterranean fruits: sour cherry pits, grape seeds, ground olive pits, and carob seeds. To evaluate the effect of treatment on the behavior of agro-waste aggregates, ground olive pits were used untreated, treated with ash water, or treated with seawater. Carob seed concrete deteriorated during water curing due to seed swelling and tannin-related degradation, revealing its unsuitability without prior stabilization. Partial replacement of natural aggregates with agricultural waste resulted in decreased density, ultrasonic pulse velocity (UPV), dynamic elastic modulus, compressive strength, and thermal conductivity, while increasing saturated water absorption. Treatment with ash water on ground olive pits improved the interfacial transition zone (ITZ), resulting in 29% increase in compressive strength relative to untreated ground olive pits. Concrete with ash water treated ground olive pits demonstrated the highest practical potential among all tested agro-waste concretes. Full article

Transitioning to a circular economy (CE) is now a strategic priority for countries to decouple economic growth from environmental degradation. However, in developing contexts, the readiness of environmental resource sectors to adopt CE principles is unknown due to a lack of data and uneven institutional capacity. This study presents the first regional baseline assessment of circularity readiness in Vietnam’s environmental resource sectors, focusing on land, mining, water and waste. A five-dimensional readiness framework (policy, resource management, innovation, business, awareness) was developed and applied across Vietnam’s six ecological–economic regions. A Delphi process with 12 experts was conducted in three rounds to capture and refine expert judgments, supplemented by triangulated proxy indicators (e.g., plastic recycling rates, wastewater treatment coverage). Readiness scores were aggregated at dimension and regional levels and analyzed using radar charts, heatmaps and hierarchical clustering. Results showed significant regional disparities. The Southeast (SE) and Red River Delta (RRD) have high readiness due to clearer policy frameworks, stronger institutions and more dynamic business ecosystems. The Northern Midlands and Mountains (NMM) and Central Highlands (CH) have low readiness due to infrastructural gaps, weak innovation and limited public engagement. The Mekong Delta (MD) and North Central Coast (NCC) have medium readiness, reflecting partial progress but uneven implementation. The study made three contributions: (1) a new context-specific framework for CE readiness in environmental resource sectors; (2) the value of expert-based, proxy-informed methods in data-scarce contexts; and (3) a policy roadmap for different regional readiness levels. Findings suggest that the CE should be integrated into resource planning, regional observatories should be established and CE-related research and development (R&D) should receive investment. Future research should move towards standardized quantitative indicators and predictive models to track how readiness changes under policy interventions. Full article