Search Results (1,172)

Green synthesis of KGM-capped CeO₂ nanoparticles was successfully achieved through a simple coprecipitation method using Konjac Glucomannan (KGM) as a biopolymeric capping and stabilizing agent. The reaction conditions were optimized by varying pH (9–11) and temperature (30–70 °C) to evaluate their influence on nanoparticle formation and photocatalytic performance. The synthesized KGM–CeO₂ nanoparticles were comprehensively characterized using FTIR, UV–Vis spectroscopy, XRD, SEM–EDS, TEM, DLS, and ZP analysis to investigate their structural, optical, morphological, and surface properties. The characterization results confirmed the successful formation of porous sponge-like branched CeO₂ nanostructures with irregular morphology. XRD analysis revealed the crystalline nature of the nanoparticles with an average crystallite size of approximately 7.7 nm, while DLS analysis showed an average hydrodynamic particle size of 29.7 nm with a biomodal particle size distribution. The positive zeta potential value (+16.75 mV) confirmed good colloidal stability and reduced agglomeration due to effective capping by KGM. The synthesized nanoparticles also exhibited favorable optical properties with band gap values suitable for photocatalytic applications. The adsorption and photocatalytic degradation performance of the KGM–CeO₂ nanoparticles was investigated against synthetic textile dyes, including Naphthol Blue Black (NBB), Methyl Orange (MO), and a mixed NBB–MO dye system under acidic conditions. Using an adsorbent dosage of 50 mg and dye concentrations of 100 mg/L, the material achieved degradation efficiencies of approximately 99% for NBB, 91% for MO, and 52% for the mixed dye system under UV irradiation for 120 min. Adsorption kinetic studies indicated that the pseudo-second-order model provided the best fit, suggesting that chemisorption is the dominant adsorption mechanism involving multifunctional surface interactions. These findings are particularly relevant for industrial wastewater treatment, since actual textile effluents typically contain complex mixtures of dyes and organic contaminants rather than single dye pollutants. The mixed dye experiments, therefore, provide a more realistic simulation of industrial wastewater conditions. Overall, the synthesized KGM–CeO₂ nanoparticles demonstrate excellent potential as an eco-friendly, cost-effective, and sustainable multifunctional material for adsorption-assisted photocatalytic treatment of dye-contaminated wastewater. Further optimization of operational conditions and catalyst surface properties may enhance its efficiency in multicomponent wastewater systems. Full article

La-MOFs exhibit strong affinity toward anions such as F⁻ and phosphate. However, conventional La-MOFs show limited regeneration performance when used as CDI electrodes, posing a major challenge for practical applications. In this study, a high-performance sulfur and nitrogen co-doped La-BDC-140-derived carbon electrode (La-CNS₃) was fabricated via a coupled carbonization and doping strategy. The optimized La-CNS₃ electrode possessed abundant defects, a mesoporous structure, favorable hydrophilicity, and rapid charge-transfer capability, which collectively enhanced fluoride electrosorption. At 1.4 V, La-CNS₃ achieved a fluoride removal capacity of 31.86 mg·g⁻¹ for 10 mg·L⁻¹ F⁻ solution and up to 195 mg·g⁻¹ at an initial F⁻ concentration of 100 mg·L⁻¹. More importantly, partial fluoride desorption was realized solely under reverse voltage, and the electrode maintained favorable defluoridation performance over 50 adsorption–desorption cycles. In actual groundwater treatment, the effluent fluoride concentration decreased to below 1.0 mg·L⁻¹ after 120 min. XPS analysis and DFT calculations revealed that fluoride removal was mainly governed by La-F coordination, surface hydroxyl/water ligand exchange, and interfacial charge redistribution. The La₂O₂S/g-C₃N₄ structure provided a favorable balance between fluoride adsorption strength and desorption reversibility. This work offers a promising strategy for designing efficient, selective, and electrically regenerable rare-earth-based CDI electrodes for fluoride-contaminated water treatment. Full article

Water scarcity and increasing environmental pressures have intensified the need for sustainable water management, including the reuse of treated wastewater. This study evaluated the continuous up-flow sand filter as a tertiary treatment process for secondary wastewater effluent. A pilot-scale filtration unit was installed downstream of the secondary treatment at Qaha Wastewater Treatment Plant (QWWTP), Egypt and operated at influent flow rates of 3.9–8.5 m³/h. Performance was assisted for removing turbidity, total suspended solids (TSS), biochemical oxygen demand (BOD₅), E. coli, total nitrogen (TN), and total phosphorus (TP), under three phases: baseline operation, variable influent quality produced by mixing secondary effluent with raw wastewater, and coagulant-assisted filtration using alum or ferric chloride. During baseline and variable influent conditions, the maximum removal efficiencies were 67.0%, 62.1% and 37.3% for turbidity, TSS and BOD₅, respectively. Alum improved the corresponding removals to 94.5%, 71.7% and 55.5%, while ferric chloride achieved 81.4%, 83.8%, and 87.5%, respectively. Overall, the results demonstrate that coagulant-assisted continuous up-flow sand filtration is a robust and practical tertiary treatment approach for upgrading secondary effluents to meet stringent wastewater reuse standards. Full article

The integration of diatom cultivation with aquaculture systems offers a promising strategy to simultaneously address nutrient-rich effluent discharge and the high costs of synthetic media. This study evaluates the growth performance, nutrient removal, CO₂ fixation, and fucoxanthin production of the marine diatom Thalassiosira sp. cultivated in three media: nitrified effluent from a recirculating aquaculture system (RAS; denoted as Aqua), synthetic F/2 medium, and a mixed medium (F/2 + Aqua, 1:1 v/v). The mixed medium demonstrated the best overall performance, indicating a synergistic effect between aquaculture-derived nutrients and targeted supplementation. After 8 days, biomass concentration reached 655 mg L⁻¹, representing a 30% and 317% increase compared with F/2 and Aqua, respectively, with a CO₂ fixation rate of 152.89 mg CO₂ L⁻¹ d⁻¹. This medium also achieved high nutrient removal efficiencies (93.67% nitrate and 97.94% phosphate) and enhanced fucoxanthin production (4.15 mg L⁻¹). In addition, biomass contained essential fatty acids, including arachidonic acid (7.12% of total fatty acid (TFA)) and eicosapentaenoic acid (7.58% TFA), supporting its suitability for aquaculture. Importantly, partial substitution of synthetic nutrients with RAS effluent reduced medium-input costs by approximately 62% while maintaining high productivity. Overall, this study demonstrates a resource-efficient, cost-effective, and sustainable approach for integrating wastewater treatment with high-value diatom biomass production, supporting circular aquaculture systems. Full article

Aquaculture in the Amazon region has considerable potential to promote the sustainable use of natural resources. The integration of fish farming and forest has emerged as a resource-efficient strategy for sustainable production. This study aimed to evaluate the growth of mahogany (Swietenia macrophylla) seedlings in integrated systems with tambaqui (Colossoma macropomum), using different spacings (5, 10, 15, 20 and 25 cm) between seedlings. After 56 days of cultivation, dissolved oxygen, conductivity, total ammonia, and nitrate were significantly affected in the systems (p < 0.05). Tambaqui growth performance differed significantly between the aquaponic systems (p < 0.05). Regarding mahogany seedlings, root fresh mass, collar diameter, and the Dickson quality index were also significantly affected by the treatments (p < 0.05). The results demonstrate that aquaculture–forestry integration, using tambaqui effluent as a nutrient source for mahogany seedlings, is a technically viable and environmentally promising production strategy. Among the treatments evaluated, the 25 cm spacing produced seedlings with superior quality attributes, suggesting that wider spacing may promote seedling development under aquaponic conditions. These findings highlight the potential of integrated aquaponic systems for the sustainable production of both forestry and aquatic resources in the Amazon region. Full article

The presence of xenobiotics in wastewater, particularly emerging contaminants such as pharmaceuticals, poses an ecotoxicological risk to the environment and human health. One of the main pharmaceutical products detected in water is diclofenac, which can be sold without a prescription. The lack of health regulations indicates the necessity of finding environmentally friendly treatment alternatives to remove this type of contaminant. Among these alternatives, biotechnology, specifically biological processes, offers a sustainable option compared to conventional treatments. Current treatment methods used in wastewater treatment plants are ineffective at removing diclofenac, a chlorinated aromatic compound highly resistant to degradation processes. In recent years, new treatment methods have gained prominence due to the favorable results they have yielded, including physicochemical, biological, and advanced processes. Biological treatments are notable for their low cost and the high level of effectiveness and efficiency with which they can remove toxic compounds. For this reason, the aim of this research project was to evaluate the degradation efficiency of a biological treatment in a bioreactor using a microbial community consisting of five bacterial strains, which was isolated from a pharmaceutical effluent and cultivated in a continuous culture system. Removal efficiencies ranging from 99.38 to 99.98% were achieved at various volumetric loading rates (from 0.087 to 1.043 g L⁻¹d⁻¹). Influents and effluents from the biological reactor were analyzed using bioassays to determine any potential toxic effects. The results showed that the effluents did not elicit a negative response in the bioindicators, indicating high toxicity in the influents. Full article

Phenol (Ph), bisphenol A (BPA), and cresol isomers (o-, m-, p-C) are pollutants widely detected in industrial effluents and resistant to conventional treatment. This study investigated the catalytic potential of manganese peroxidase (MnP), derived from Phanerochaete chrysosporium and expressed in corn, for the removal, via oxidative oligomerization and precipitation, of these compounds from water. Batch experiments were conducted under controlled pH, hydrogen peroxide concentration, and enzyme activity to achieve ≥95% substrate conversion. The optimized MnP system nearly achieved this under stepwise hydrogen peroxide addition. Kinetic analyses revealed short half-lives for initial degradation phases, with BPA and p-C showing near-instantaneous transformation. Mass spectrometry confirmed the formation of soluble and insoluble oligomers (to hexamers for BPA, octamers for p-C, dodecamers for the rest), confirming radical-mediated polymerization pathways. These findings highlight MnP as a robust and eco-friendly biocatalyst for efficient treatment of phenolic pollutants, offering significant potential for integration into advanced wastewater treatment systems. Full article

This study evaluates the performance of natural plant-derived coagulants as sustainable alternatives to conventional chemical coagulants in water treatment. Surface water samples were collected from the Meda Ela stream in Karadiyana, Sri Lanka, which is an urban water body impacted by leachate from the Karadiyana dumpsite, industrial discharges, and urban runoff. Grab samples were analyzed for key water quality parameters, including pH, conductivity, turbidity, dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), settleable solids, total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), total nitrogen, and total phosphorus. Several parameters exceeded permissible standards established by the Central Environmental Authority (CEA) of Sri Lanka, including turbidity (35 NTU; limit: 20 NTU), COD (80 mg/L; limit: 15 mg/L), TDS (1000 mg/L; limit: 500 mg/L), and TSS (100 mg/L; limit: 40 mg/L), indicating significant pollution levels. Jar test experiments were conducted to compare the coagulation efficiency of cowpea seeds (75.8%), fenugreek seeds (69.2%), papaya seeds (72.5%), okra pods (84.6%), and Moringa oleifera (drumstick) leaves (87%) with conventional alum (94.2%) at an optimum dosage of 12 mL/L. Among the tested plant-derived coagulants, Moringa oleifera leaves demonstrated the highest turbidity removal efficiency, reducing residual turbidity to 4.54 NTU. A low-cost integrated treatment system incorporating coagulation, flocculation, sedimentation, and filtration using sawdust and cotton wool was developed, achieving average removal efficiencies of 90.13% for turbidity, 88.57% for COD, 83.46% for TDS, and 74.83% for TSS, with all effluent parameters maintained within CEA permissible limits. The results confirm that locally available plant-derived coagulants, particularly Moringa oleifera leaves, offer an effective, environmentally friendly, and economically viable approach for sustainable water treatment, highlighting the potential of nature-based solutions in strengthening climate-resilient water management strategies. Full article

This study evaluated the degradation of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) in simulated wastewater using an iron-carbon (Fe-C) micro-electrolysis system. The treatment efficiency was systematically evaluated under varying initial pH, Fe dosage, and Fe/C mass ratios. Under the optimized operating conditions (initial pH of 4, Fe dosage of 70 g/L, and an Fe/C mass rat of 1:1), the system achieved a maximum HMX removal efficiency of 98.4%. Kinetic analysis indicated that the degradation process conformed to pseudo-first-order kinetics. Mechanistically, HMX removal was attributed to interfacial adsorption and co-precipitation via in situ generated Fe²⁺ and Fe³⁺ hydroxides, alongside reductive transformation mediated by Fe, Fe²⁺, and nascent hydrogen ([H]) evolved during the micro-electrolysis process. To assess the molecular toxicity evolution of the treated wastewater, a toxicogenomic assay was deployed to evaluate the molecular toxicity evolution of the treated wastewater matrix. The transcriptomic profiling revealed that DNA damage and oxidative stress were the predominant cellular stress responses induced by the wastewater. While the total toxic effect transcript index (TELI_total) exhibited a transient initial increase before steadily declining, the overall toxic potency remained within a relatively stable range throughout the treatment cycle. Ultimately, this study provides critical insights into process optimization and pathway elucidation, demonstrating that Fe-C micro-electrolysis is a promising and scalable pretreatment technology for the remediation of energetic compound-laden industrial effluents. Full article

The disinfection process in wastewater treatment is key to the discharge and/or reuse of high-quality effluent. However, disinfection using ultraviolet (UV) light may be inefficient because bacteria possess mechanisms for repairing damaged DNA. This study aimed to assess the photoreactivation and dark repair of total coliform (TC) in wastewater effluent after UV-C disinfection treatment. Four UV-C doses (28.8, 53.1, 57.6, and 106.2 mJ/cm²) and two post-irradiation conditions (light vs. darkness) were applied. Reactivation was monitored after 2, 4, 6 and 24 h (25 °C). Similar TC inactivation efficiencies were observed for the three lowest UV-C doses, whereas the 106.2 mJ/cm² dose achieved the greatest reduction (1.1 Log of TC), decreasing TC concentrations from 3.1 × 10⁵ ± 3.5 × 10⁵ to 1.2 × 10⁵ ± 1.4 × 10⁵ MPN/100 mL. Reactivation assays revealed substantial bacterial recovery after UV treatment, with 24 h survival rates up to 2.3 × 10³ under light and 9.2 × 10² in darkness. Photoreactivation and dark repair assays revealed substantial variability in bacterial recovery after UV treatment depending on UV-C dose, post-irradiation condition and incubation time. In general, bacterial recovery was still detected even at the 106.2 mJ/cm² dose, particularly after 24 h of incubation (178–604%). These findings suggest that effective organic matter removal before UV-C disinfection is critical to improve UV transmittance, reduce shielding effects, and limit subsequent bacterial recovery. 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

Scale deposition, particularly calcium sulfate, poses a major challenge in carbonate reservoirs, leading to permeability reduction and operational inefficiencies. In this study, the performance of a polymeric scale inhibitor, polyphosphinocarboxylic acid (PPCA), was systematically investigated through dynamic core flooding experiments combined with statistical modeling. To address scale inhibition performance and minimum inhibitor requirements, additional static jar tests and dynamic tube blocking experiments were conducted. The results confirmed a minimum inhibitory concentration (MIC) of 40 ppm PPCA, where inhibition efficiency exceeded 90% at elevated temperatures. Moreover, the desorption behavior of PPCA was evaluated under a wide range of operational conditions, including pore volume (0–40 PV), temperature (50–100 °C), injection rate (2–6 mL/min), and pH (6–8). Effluent concentrations were quantified using a spectrophotometric method and expressed as the C_f/C_i ratio (effluent concentration to injected concentration) to characterize inhibitor return behavior. A comprehensive dataset comprising 224 experimental runs was analyzed using Response Surface Methodology (RSM), leading to the development of two predictive models for low (0–10 PV) and high (10–40 PV) pore volume ranges. The models demonstrated excellent predictive capability, with R² values of 0.9934 and 0.9979, respectively. In addition, statistical analysis confirmed that pore volume and injection rate were the most influential parameters, while pH exhibited a comparatively minor effect. Results showed that increasing PV, temperature, injection rate, and pH led to a decrease in C_f/C_i, indicating enhanced desorption. For instance, C_f/C_i decreased from approximately 0.12 at 10 PV to 0.06 at 40 PV under reference conditions. Furthermore, optimization results revealed that maintaining an effective inhibitor concentration (C_f/C_i more than 0.05) is strongly dependent on operating conditions. At 60 °C, a wide operational window was observed, whereas at 100 °C, the effective region significantly narrowed due to accelerated desorption. Furthermore, permeability reduction analysis (K_d/K_i) demonstrated significant suppression of scale-induced formation damage in the presence of PPCA, while blank tests showed severe permeability decline. The integrated results validate the dual role of PPCA in both scale inhibition efficiency and formation protection under dynamic conditions. The novelty of this work lies in integrating polymer-specific behavior with dynamic core flooding and multivariable statistical modeling, providing a robust predictive framework for optimizing squeeze treatment design in carbonate reservoirs. 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

Wastewater membrane bioreactors (MBRs) have become an important advanced treatment technology due to their ability to produce high-quality effluent suitable for discharge and water reuse. However, their broader and more sustainable application remains constrained by membrane fouling, elevated energy demand, and the operational complexity of coupled biological and membrane separation processes. This comprehensive review critically evaluates the growing application of machine learning (ML), explainable artificial intelligence (XAI), and digital twin (DT) technologies in MBR systems. Published studies on fouling prediction, energy optimization, effluent quality estimation, and intelligent operational support are critically evaluated, with explicit attention to model performance, dataset limitations, and generalizability. The reviewed literature shows that ML models, particularly ensemble methods, support vector machines, and deep learning approaches, have demonstrated strong potential for predicting major MBR performance indicators, including transmembrane pressure, permeate flux, fouling resistance, and selected effluent-quality variables. In parallel, XAI methods such as SHAP, LIME, and Anchors are increasingly being used to enhance model transparency and to reveal the dominant factors controlling process performance. Digital twin frameworks further extend this potential by enabling the integration of mechanistic understanding, online sensor data, data-driven prediction, and interpretable decision support within real-time operational platforms. Nevertheless, several barriers continue to hinder practical implementation, including the limited number of full-scale studies, the scarcity of openly accessible and standardized datasets, insufficient consideration of uncertainty and model drift, and the early-stage maturity of DT deployment in operational plants. The evidence reviewed suggests that integrating ML, XAI, and DT can substantially improve the reliability, interpretability, and operational efficiency of MBR systems. Future research should therefore focus on full-scale validation, the development of benchmark datasets, uncertainty-aware modeling, and practical deployment strategies for interpretable intelligent MBR management. Full article

This study investigates the separation performance of transformer oil–water mixtures using gravity separation and chemical demulsification. The synthetic emulsion had an initial oil concentration (C₀) of approximately 246,000 mg/L. For gravity separation, the effects of compartment volume ratio, influent flow rate, initial water level, and oil discharge strategy were systematically evaluated. Under optimal conditions (volume ratio 2:1:1, flow rate 0.0055 L/s, initial water level 5 cm), the effluent oil concentration was reduced to as low as 0.020 mg/L, corresponding to a removal efficiency higher than 99.99%. For chemical demulsification, polyaluminum chloride (PAC), polyferric sulfate (PFS), polyacrylamide (PAM), and an organosilicon polyether demulsifier (MCL-D) were tested. The effects of pH, dosage, and temperature on demulsification efficiency (DE) and dehydration rate (DR) were investigated. Under optimal conditions (pH 3–5, dosage 300 mg/L, temperature 50 °C), MCL-D achieved the best performance, with a DE of 95.09% and a DR of 99.50%. Overall, gravity separation is effective for removing free and dispersed oil with low operational cost, whereas chemical demulsification is more suitable for treating stable emulsified oil. The combination of these two methods provides an efficient strategy for the treatment of transformer oil-containing wastewater. Full article