Journal of Environmental Management最新文献

Recent studies have demonstrated the potential of contact electro-catalysis (CEC) for degrading organic pollutants in wastewater through interfacial electron transfer mechanisms. However, practical applications of CEC are hindered by the limited efficiency of existing catalysts and the lack of reaction condition adaptability. In this study, we modified titanium silicalite-1 (TS-1) zeolite with Fe₂O₃ nanoparticles and polytetrafluoroethylene (PTFE), creating a composite (Fe₂O₃/TS-1@PTFE) to remove oxytetracycline (OTC) from water via synergistic adsorption and degradation by the reactive oxygen species (ROS) and H₂O₂. A near-complete (98%) removal performance was achieved within 60 min at pH = 7 and a temperature 25 °C, with catalyst dosage of 0.5 g/L and an initial OTC concentration of 5 mg/L. It demonstrated that the degradation corresponded to pseudo-first-order kinetics model with a kinetic constant of 0.05 min^-1. During the degradation, it was revealed that ROS assumed a dominant role, with Fenton-like reactions playing a secondary but significant part; consequently, an innovative self-cycling Fenton-like mechanism was proposed. The system also demonstrated strong anti-interference capability, stability, and efficacy in real water samples. This work provides us with a strategy, namely, employing self-cycling Fenton-like reactions as a supplementary means to further enhance the degradation efficiency while utilizing ROS for pollutant degradation.

Metal slag has become an increasing environmental concern because of its hazardous constituents, prompting global initiatives to remove historical stockpiles as part of soil remediation programs. However, evaluating the effectiveness of these clearance efforts remains challenging, as residual slag-derived contamination is difficult to distinguish from geogenic backgrounds or anthropogenic inputs. This study aims to quantitatively assess the efficacy of aluminum-steel slag stockpile clearance by integrating lead (Pb) isotopic signatures with partial extraction techniques to evaluate changes in soil contamination before and after remediation. Based on the significant correlation between 1/Pb and the ²⁰⁶Pb/²⁰⁷Pb ratio, a binary mixing model was employed for source apportionment, thereby confirming a shared metal slag source. Model calculations indicate a significant reduction in the relative contribution of metal slag, which decreased from 95.2% pre-clearance to 41.4% post-clearance, reflecting a reduction of approximately 55.9%. Meanwhile, the absolute Pb concentration fell dramatically from 557.3 mg/kg to 20.6 mg/kg, representing a decrease of about 96.3%. This notable divergence underscores that while absolute mass reduction validates the effectiveness of remediation efforts, the persistent relative contributions highlight reconfigured source dynamics crucial for long-term stewardship. Our study establishes Pb isotopic analysis as a robust methodology that surpasses conventional bulk concentration measurements in assessing the success of environmental cleanup.

Nowadays, because of their widespread applications in thermal efficiency enhancement, combined power cycles have attracted the attention and interest of the researchers. This research is devoted to provide a comprehensive modeling and thermal analysis of a new arrangement of combined cycle based on a compression ignition (CI) engine and α-type Stirling engine. Furthermore, the influences of the diesel exhaust gas temperature and Stirling working pressure on Stirling and combined engines power and efficiency are examined considering various scenarios. The Stirling engine cycle is combined with a CI engine cycle to recover the CI engine exhaust gas waste heat. OM355 experimental results have been considered for generated power, thermal balance and exhaust gas temperature analysis. According to thermal analysis and the obtained results, it is revealed that about 34% of input energy wastes by the exhaust gas. The simulation of α-type Stirling engine is also performed and the Solo V161 experimental results were employed for validation. Furthermore, Stirling engine heater is suggested for installation on the exhaust pipe in order to analyze the new proposed combined cycle properties. Thermodynamic analysis of combined cycle is implemented and thermal efficiency and net power are obtained for Striling engine, diesel engine and combined cycle for various Stirling engine and diesel exhaust temperatures. The results indicate that, by installing a Stirling engine heater on the exhaust pipe of the CI engine, about 9.3 kW of the wasted heat could be recovered. Compared to the ordinary engine, coupled engines heat balance reveals higher thermal efficiency and combined cycle power which increase by 7.3% and 5.6%, respectively.

Run-of-river hydropower (RoR HP) systems are gaining prominence as sustainable energy alternatives because of their reduced ecological footprint compared with that of reservoir-based installations. However, in some regions, seasonal flow variability poses challenges for consistent energy generation and operational efficiency. This study introduces a novel framework that integrates continuous wavelet transform (CWT) and flow duration curve (FDC) analyses to evaluate hydropower potential by quantifying functional flow rates (FFRs) while accounting for flow regime continuity, which is a critical factor often overlooked in conventional assessments. Using a 22-year hourly discharge dataset from a subtropical watershed, we applied the CWT with a Morlet wavelet basis to decompose flow time series data, identifying dominant temporal scales via the global wavelet power spectrum. The results revealed primary (1 year) and secondary (3.5 years) hydrological cycles, reflecting the seasonal and interannual flow variabilities that directly impact hydropower feasibility. FFR thresholds were derived via continuous exceedance probability (CEP), which incorporates temporal flow continuity, and compared with traditional discrete exceedance probability (DEP) methods. Key findings indicate that the conventional DEP-based FDC approach systematically overestimates useable hydropower potential because it aggregates flow magnitudes without considering temporal sequencing and continuity, and this bias becomes more pronounced under strong seasonal variability. Across the evaluated continuity thresholds (3-24 h), CEP yields consistently lower and more operationally realistic energy and capacity-factor estimates than DEP. The dry-season flows consistently exceeded the CEP thresholds, whereas the wet-season flows exhibited high variability, necessitating adaptive operational strategies. Contrary to conventional insight, the dry season typically maintains a more continuous and available flow within a moderate discharge range. By prioritizing temporal continuity, the CEP framework provides a robust tool for policymakers and developers to mitigate financial risk, enhance climate resilience, and safeguard aquatic ecosystems. RoR systems can optimize energy output while minimizing risks from overestimated capacity factors by aligning installed capacity with CEP-derived thresholds. The proposed methodology reduces operational uncertainties and enhances the viability of RoR systems as low-impact renewable energy solutions, supporting climate resilience and environmental management goals.

This study quantified volatile fatty acid (VFA) production using semi-continuous, arrested anaerobic digestion (aAD) of food waste (FW) and high salinity glycerol sludge (HSGS) derived from plant-based biodiesel processing. FW and HSGS were tested at five ratios (100:0, 75:25, 50:50, 25:75, 0:100). The alkaline pH (9 - 10) conditions and high organic load (6.3 - 17.8 g VS/L-day) with HSGS inclusion resulted in higher VFA production, despite the high salinity (214 g/L NaCl) of HSGS. The VFAs produced from mono-aAD of HSGS (36.04 g/L VFAs) were significantly higher than aAD of FW (9.29 g/L), with the highest VFA concentration observed on Day 51. The FW-only treatment produced the most VFAs per unit of VS loaded during steady state (0.65 - 1.24 g VFA/g VS), yet the wide range of salinity concentrations (53.5 - 214 g/L NaCl) with FW and HSGS co-aAD did not significantly influence VFA production efficiency (p > 0.05). The inclusion of HSGS increased VFA production and mitigated acidic inhibition during aAD of FW. No potassium hydroxide (KOH) additions were needed to buffer acidic conditions during aAD when HSGS inclusion was greater than 50%, and KOH additions with 75:25 ratio of FW:HSGS was 95% less than FW-only. HSGS inclusion drove a shift from a community dominated by Olsenella and Methanobrevibacter to communities with higher diversity and a higher proportion of acetic acid producing fermenters. This work showed that HSGS inclusion increases VFA production when used singularly or with FW, with high VFA concentrations available for processing into bioplastics, bioenergy, or pharmaceuticals.

Sediment addition is an increasingly common strategy to promote coastal resilience where sediment is added to salt marsh surfaces to increase elevation and prevent marsh loss. Added sediments are typically dredged materials from marine environments that may become acidic when exposed to air because of their high reduced sulfide levels, known as potential acid sulfate soils (PASS). Low soil pH inhibits plant growth and can delay ecosystem recovery after sediment addition. We used a laboratory soil core experiment to evaluate how a range of amendments altered pH (mulch, crushed shells, pelletized lime, and recycled concrete), and a field study to examine the effects of recycled concrete. We found that concrete amended sediment (laboratory: 8.24 ± 0.32; field: 8.15 ± 0.55) increased pH relative to adding unamended sediment (laboratory: 7.33 ± 0.35; field: 7.21 ± 0.45). Environmental context is likely important for sediment additions and even PASS may not become acidic in flooded, low marsh environments. Under more oxidized conditions, particularly in higher-elevation marsh or when deeper layers of sediment are added, recycled concrete is a potential amendment to neutralize acidity. Sediment amendments may also affect other ecosystem responses, including water chemistry and greenhouse gas emissions. We found that concrete amendments lowered ferrous iron concentrations and decreased carbon dioxide emissions compared to adding unamended sediment. Additional testing of amendments under diverse environmental conditions and at field scales would further our understanding of the effectiveness and feasibility of amending soils during sediment additions to prevent acid sulfate soil development.

Microalgae-nitrifier consortium is a promising sustainable wastewater treatment technology, however, accumulation of toxic nitrite inhibited microalgal growth and compromised system stability. This research studied the interrelation between nitrite metabolism and toxicity under free nitrous acid (FNA) and dissociated nitrite (NO₂^-) stress in microalgae to reveal regulation mechanism of nitrite assimilation and inhibition. Results showed that toxic threshold of FNA (40 μg N/L) on Tribonema minus was much lower than NO₂^- (450 mg N/L) and FNA stress down-regulated PsbO and ferredoxin-NADP⁺ reductase, causing irreversible damage to photosystem II, whereas NO₂^- stress suppressed the NDH complex that drove cyclic electron flow around photosystem I. Inhibition of both FNA and NO₂^- on microalgal growth were highly correlated with intracellular nitrite content, following exponential and logarithmic relationships, respectively. Chloroplast proteomics revealed that neither FNA nor NO₂^- directly repressed nitrite reductase (NiR) synthesis. Instead, excessive FNA diffused passively across membrane, collapsed photosynthetic electron transport and subsequently inactivated NiR, provoking further intracellular nitrite build-up. Under NO₂^- stress, accelerated nitrite influx overloaded the nitrogen-assimilatory machinery, down-regulated glutamate synthase (GOGAT) and disrupted the nitrogen assimilation, ultimately inactivated NiR, thereby exacerbating intracellular nitrite accumulation. Notably, FNA and NO₂^- stress redirected more carbon flux to carbohydrate and lipid whose content was 3.6-9.3 % and 4.5-10.1 % higher than control, respectively. The intracellular nitrite accumulation processes in T. minus during inhibition of FNA and NO₂^- were elucidated and methods including increasing extracellular polymeric substances content or supplementing exogenous substrate were proposed to reduce passive diffusion and enhance nitrite assimilation.

The upper Yellow River is a crucial ecological barrier and water conservation zone in the Yellow River Basin. Since 2000, extensive afforestation in this region has markedly improved the carbon sequestration capacity. Nevertheless, the responses of soil C:N:P stoichiometry and microbial diversity to different vegetation restoration patterns remain insufficiently understood. This study was conducted at a representative restoration site (Erlang Mountain) in the upper Yellow River. Abandoned farmland (Af, abandoned for more than three years) was used as the background, and six types of plantations with a uniform recovery period of 20 years were selected: mixed forest (Mf), Hippophae rhamnoides (Hr), Picea crassifolia (Pc), Prunus sibirica (Ps), Larix gmelinii (Lg), and Pinus tabuliformis (Pt). These tree species are widely used for afforestation in the upper Yellow River region and represent the dominant vegetation restoration strategies. Using 16S rRNA and ITS amplicon sequencing, this study clarified the mechanisms underlying soil microbial diversity and C:N:P stoichiometry across these restoration types. The results revealed the following. (1) Soil C (SOC) and N (TN) contents and stocks were the highest in Mf but the lowest in Hr (P < 0.05). Except for Mf, the soil C and N contents and stocks in the Lg forests exceeded those in the other stands (P < 0.05), whereasthe soil P (TP) in Pt was the lowest (P < 0.05). (2) The soil bacterial α-diversity in Mf and Lg was greater than that in other afforestation lands (P < 0.05), with Mf exhibiting the highest α-diversity, dominated by Acidobacteriota and Pyrinomonadaceae. The soil fungal α-diversity in Cl exceeded that of the other land use types (P < 0.05). The abundance of Acidobacteriota in Hr soils was lower than that in other forests, whereas the abundances of Ascomycota and Mortierellaceae were higher. (3) Precipitation exerted a negative effect on soil C:N:P stoichiometry but a positive effect on bacterial α-diversity (P < 0.05). pRDA analysis indicated that the vegetation restoration type significantly influenced soil C:N:P stoichiometry and microbial diversity (P < 0.05). This study demonstrated that vegetation restoration reshaping microbial community composition and improving soil C and N contents, with Mf and Lg exerting a stronger effect than other vegetation restoration types, thereby providing insights into rational afforestation in these regions.

Magnetic coagulation using magnetic powder with polyaluminum chloride and polyacrylamide is a promising option for aquaculture wastewater treatment, yet practical deployment is constrained by the need for real-time multi-chemical dosing under highly variable influent conditions. This study develops and validates an automated, control-oriented framework for optimizing combined magnetic coagulant and coagulant-aid dosages during dynamic operation. A fast data-driven surrogate based on an Extreme Learning Machine (ELM) was constructed and tuned with Grey Wolf Optimizer (GWO), and dosing decisions were formulated as a desirability-based, chance-constrained optimization problem to account for multi-objective trade-offs and reliability. The optimized setpoints were implemented through a feedforward-feedback controller, while Shapley Additive Explanations and partial dependence plots were used to interpret dose-response patterns and chemical interactions. Using lab-scale dynamic datasets, GWO tuning improved geometric-mean desirability by 0.12-0.29 and reduced prediction errors by 13-38%. Under abrupt disturbances, the GWO-ELM-PID strategy achieved 99.7% on-specification time and reduced total chemical consumption by 9.98% and 7.82% compared with open-loop and conventional proportional-integral-derivative strategies, respectively. These results support a reliable, interpretable, and deployable framework for real-time multi-chemical coagulation control.

Modern internal combustion engines must satisfy increasingly strict and often conflicting requirements: high torque demand must be delivered without sacrificing fuel efficiency, while emissions compliance depends on maintaining suitable exhaust thermal conditions for effective aftertreatment operation. These objectives are strongly coupled and highly nonlinear, so improving one metric can deteriorate others, and the feasible region is further constrained by complex actuator interactions and operating-regime variability. To address this challenge, this study applies a suite of recent bio-inspired metaheuristic algorithms to multi-target engine calibration, leveraging their derivative-free global search capability to handle multimodality, nonconvexity, and black-box constraints that limit conventional gradient-based tuning. A high-fidelity surrogate model was first constructed from a public engine dataset using Principal Component Analysis (PCA) and Gaussian Process Regression (GPR) and validated via k-fold cross-validation, enabling fast and accurate prediction of torque, brake thermal efficiency (BTE), and exhaust gas temperature as the fitness function. Five optimizers were then benchmarked in terms of solution quality and convergence behavior in this realistic calibration setting: Meerkat Optimization Algorithm (MOA), Dumbo Octopus Algorithm (DOA), Pufferfish Optimization Algorithm (POA), Hybrid Jellyfish Search-Particle Swarm Optimization (HJSPSO), and Dendritic Growth Optimization (DGO). Finally, an automated DOA-based calibration workflow was used to generate efficiency-oriented control maps. Across all tested operating conditions, the DOA-based calibration maintained percentage errors of up to 6% relative to all reference targets, with the analysis focused on high-efficiency setpoints, as indicated by BTE reference values of at least 30%.