Environmental Technology最新文献

This study deciphers sludge biodrying through a microbial-structural coevolution framework: Thermophilic consortia (Geobacillus/Bacillus; 63.27% abundance) drive bio-heat generation (>65°C), triggering particle fragmentation (decreased particle size by 63%), pore-network expansion (SEM-validated), and matrix loosening (decreased fractal dimension by 32%). This structural evolution enables phase-specific moisture redistribution - surface water (decreased from 68.52% to 19.82%) transforms into interstitial water (increased from 28.71% to 69.08%) and ultimately vapour flux, a process accelerated by capillary migration and enhanced airflow diffusion. The synergy of microbial succession (with dominance shifting from Firmicutes to Actinobacteria), structural reconfiguration, and moisture thermodynamics achieves deep dewatering (reducing moisture content from 80.62% to 41.62%), while mechanistic insights enable precision aeration phasing for energy reduction and cycle shortening via moisture-state-guided control.

This study proposes an inverse support vector machine (ISVM) framework to optimise aeration control in a sequencing batch reactor(SBR), addressing the balancing of energy efficiency and regulatory compliance in wastewater treatment. By integrating data-driven modelling with constrained optimisation, the method dynamically adjusts aeration rate to maintain effluent NH₃-N concentrations below 5 mg/L while minimising energy consumption. A support vector machine (SVM) establishes input-output correlations between process parameters (influent NH₃-N, ORP, conductivity, aeration rate) and effluent NH₃-N concentration, enabling the ISVM to resolve constraint-driven aeration rate optimisation. Experimental validation across 20 operational cycles demonstrated a 20.3% reduction in energy usage compared to conventional fixed-rate aeration, achieving 95% compliance with discharge standards. The framework's penalty-based optimisation and gradient clipping mechanisms ensure stability in applications, overcoming limitations of traditional PID controllers and mechanistic models. This work advances intelligent control strategies for sustainable wastewater management, providing a constraint-aware optimisation template for environmental engineering systems.

Soil acidity, specifically the presence of Al ^+ 3 at toxic levels for most crop plants, is one of the main factors limiting agricultural production. However, the relationship between organic acid exudation and its direct influence and magnitude on aluminium tolerance in rice plants remains poorly elucidated in the literature. In order to verify the complexing effect of organic acids on Al, trials were carried out with rainfed rice seedlings of the Comum Branco and Caiapó varieties, under controlled growth conditions, in addition to evaluating the exudation of organic acids and possible changes in their internal root contents as a function of Al. It can be concluded that citric acid was effective in mitigating the toxic effects of Al³⁺ on the root system of the evaluated rice cultivars. In the absence of aluminium, malic acid promoted an increase in root length. The cultivar Comum Branco exhibited a greater tolerance to Al³⁺ compared to Caiapó, which may be associated with its higher exudation and accumulation of organic acids in the roots. These results suggest that the action of these mechanisms contributes to the greater aluminium tolerance observed in this cultivar.

Microplastics (MPs) and nanoplastics (NPs) have attracted widespread attention due to their detrimental effects on the ecosystem and human health. NPs, which are smaller and more harmful than MPs, are generated during the degradation of MPs. The present study aimed to inhibit the release of polyvinylchloride NPs (PVC-NPs) generated during the degradation of PCV-MPs, by using Ultraviolet/ sulphite (UV/SO₃^2-) in the presence of O₂ (UV/SO₃^2-/O₂). Under optimal conditions, the dechlorination rate and weight loss of PVC-MP were 72.4% and 61.7%, respectively. The chemical changes of the treated PVC-MPs and the intermediates during the degradation of PVC-MPs were investigated. It was confirmed that PVC-NPs form during the degradation PVC-MPs. In addition, PVC-NPs were successfully removed from the water by superoxide ion (O₂^-)-induced self-flocculation, resulting in a reduced release of PVC-NPs into the water. The weight of the self-flocculation containing PVC-NPs was 5.2 mg. Self-flocculation was investigated by scanning electron microscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy. Numerous C-O-C groups were identified in the self-flocculation. The results indicate a potential process for the removal of PVC-NPs by self-flocculation. This study introduces a new method of degradation of PVC-MPs while simultaneously reducing the release of PVC-NPs.

The ubiquity of electronic devices has made them indispensable in daily life. Nevertheless, this high priority leads to a surge in electronic waste, or e-waste, which is extremely dangerous for the environment and human health. E-waste contributes to environmental pollution and threatens ecosystems and human health. Management of recycling methods and efficient e-waste is crucial to lower these dangers. Traditional recycling techniques are effective, but often release harmful pollutants. The present study has attempted to use the metal-resistant Exiguobacterium himgiriensis isolated from e-waste, such as the Printed Circuit Board (PCB), to investigate its efficiency in removing heavy metals from these substrates. By using ICP-OES, it has been found that this species of bacterium recovered different types of metals (Co 84.67%, Ni 83.25%, Pb 80.17%, Cu 80.06%, Zn 76.71%, Al 76.13%, Fe 71.74%, and Ag 64.97% respectively) within 5 days under laboratory conditions. Detecting structural and functional group changes in the control PCB and bioleached residue by the FT-IR, FE-SEM, EDS, and XRD techniques confirms the evidence of bioleaching. Bacteria can increase their dissolving capacity and decrease surface tension by chemically changing metals. E. himgiriensis bioleaches PCB samples for 5 days, resulting in rougher, uneven surfaces with fractures and fissures. FT-IR spectroscopy reveals the bacterium's impact on metals, particularly Si, O, and Fe. This study could help reduce environmental pollution and health risks associated with e-waste by developing an economical and environmentally friendly method for bioleaching different metals in PCB.

With the increasing generation of spent lithium-ion batteries (LIBs), there is an urgent need for efficient and environmentally friendly recycling methods. Compared to traditional pyrometallurgical and hydrometallurgical processes, deep eutectic solvents (DESs) offer advantages for recycling valuable metals from spent LIBs, including better biocompatibility and high recovery efficiency. However, complex procedures, long processing times, and solvent regeneration remain challenges. To address these limitations, we propose a streamlined recycling approach using a DES synthesised from guanidine hydrochloride (GUC) and tartaric acid (TA). This method promotes Li enrichment in the leachate while Co, Ni, and Mn mainly precipitate. Adding ethanol as an antisolvent enhances crystallisation and precipitation, producing Li-rich solutions and precursors containing only trace amounts of Li for Co-Ni-Mn (NCM) cathodes. Subsequent carbonisation converts Li into Li₂CO₃, which is then mixed with precursors in controlled ratios and subjected to high-temperature solid-state sintering to regenerate NCM cathode materials. Notably, ethanol and the DES are recovered by distillation with recovery efficiencies of 91.6% and 80%, respectively. This optimised process achieves leaching of NCM cathode materials under mild conditions and significantly improves the separation efficiency between Li and Co/Ni/Mn through a simplified workflow. Overall recovery efficiencies reach 97.51% for Li, 98.57% for Ni, 100% for Co, and 97.24% for Mn in regenerated NCM materials. This study presents a green, efficient, and simplified method for recovering valuable metals from spent LIB cathode materials.

The environmental spread of antimicrobial resistance genes (ARGs) through the use of animal manure in agriculture has become a significant concern. This study investigated the impact of applying swine manure treated through biodigestion on the spread of ARGs in agricultural soils in the Midwest region of Brazil. Samples of untreated and treated manure, fertilized soil, and unfertilized soil were collected from three piglet production units. Bacterial communities and ARGs were characterized through metagenomic sequencing and bioinformatics. Bacterial profiles in fertilized and unfertilized soils were highly similar across all farms. In contrast, biodigestion reduced the total number of ARGs in treated manure. Of the 399 ARGs detected in fertilized soils, 67% were also found in unfertilized soils, and 12% were shared exclusively with treated manure. The presence of numerous ARGs in unfertilized soils highlights the role of environmental dissemination routes, such as runoff, dust, or wildlife, in shaping soil resistomes even in areas without manure application. These findings suggest a stable bacterial and resistome profile in soils, regardless of manure application. Although antimicrobial residues were not evaluated, the results reinforce the need for responsible antibiotic use and effective manure management to minimize environmental ARG dissemination.

An investigation was conducted to evaluate hydraulic performance and chemical clogging of the concrete permeable reactive barrier (PRB) used to treat acid mine drainage (AMD). The pervious concrete PRB system is an emerging technology for AMD treatment. In the present study, pervious concrete mixtures were prepared at a 0.27 water/cementitious ratio using CEM I 52.5R cement with or without 30% fly ash and 9.5 mm granite aggregate. The AMD types used were obtained from a gold mine and from a coal mine. Porosity and permeability properties of the pervious concretes were measured before and after use to treat AMD. Subsequently, 2D slice image analyses were done using X-ray microcomputed tomography (microCT). It was found that the heavy metals comprising Al, Zn, Fe, Mn, Mg, Ni and Co, were removed at the high removal efficiency (RE) levels of 70-100%. Interestingly, critical reductions in porosity (P-crit) and permeability (K-crit) values were utmost at a short distance of 75 mm from the entrance, forming bottleneck clogging. Results showed that chemical clogging that ensued progressively during the experiment, adversely gave values of up to 30-40% reduction in RE values, up to 30-40% reduction in P-crit and 80-90% reduction in K-crit. MicroCT analysis of pore connectivity confirmed the occurrence of bottleneck clogging in the column reactors. Further studies are needed to investigate the long-term adverse impacts of chemical clogging that could potentially be employed to determine the PRB's longevity.

Fungal laccases are eco-friendly biocatalysts capable of oxidizing a broad spectrum of compounds. In this study, four fungal species were cultivated to evaluate laccase production and their application in the bioremediation of acetaminophen and diclofenac. Among these, Pycnoporus sanguineus exhibited the highest laccase activity (1116.94 U/mL). SDS-PAGE profiling of laccase crude extracts (LCEs) revealed multiple protein bands, while zymograms confirmed the presence of distinct isoforms. Stability assays demonstrated that glycerol protected laccase activity in a concentration- and source-dependent manner, with laccase from Trametes sp. 50/08 showing the most gradual decline over 60 days. When examining the efficacy of bioremediation, the LCE from Marasmiellus palmivorus at 10 U/mL achieved 96% acetaminophen removal within 24 h, whereas the LCE from Agaricus blazei at 30 U/mL was the most effective for diclofenac, achieving 82% removal. However, increasing laccase concentration did not enhance pharmaceutical degradation, suggesting possible substrate saturation or inhibition. These findings highlight the efficiency of crude enzyme extracts in removing acetaminophen and diclofenac, reinforcing their potential as sustainable tools for treating pharmaceutical pollutants in aquatic environments.

Total and volatile mixed liquor suspended solids concentrations (MLSS and MLVSS) are key parameters in activated sludge (AS) process design, monitoring, and modelling. Yet for the emerging AS version of aerobic granular sludge (AGS), representative sampling and pipetting of the granular mixed liquors are challenging, leading to uncertainties when measuring the suspended solids by standard methods. In this study, new MLSS methods based on correct sampling principles were developed and evaluated to determine the suspended solids (SS) of AGS reactors. Method-1 used as a reference consisted of sacrificing the whole mixed liquor (ML) of each reactor as an exhaustive sample that was all ground to determine the total solids (TS) of the slurry; this allowed for accurate estimates of the MLSS and its volatile fractions (ivt_bio), which, in turn, led to the MLVSS. In parallel, Methods-2 and -4 were tested, both based on small homogeneous subsamples of ML, which were ground or drained before measuring the total solids of the slurry or of the drained granule paste. Compared to the reference, these latter methods allowed the MLSS and ivt_bio of AGS with large granules to be determined with much greater accuracy than the current standard Method-3 (direct SS measurement). The study's good sampling practices are readily applicable to laboratory reactors and would henceforth improve solids measurement in AGS research. At large plants, the developed procedures of subsampling, granule grinding or draining, and MLSS calculation formulas would reduce sampling errors and enhance process monitoring.