This study investigated the spatiotemporal evolution of typical antibiotic resistance genes (ARGs) and their response mechanisms to antibiotic stress in the system of continuous flow aerobic granular sludge-membrane bioreactor (AGS-MBR). Comparative experiments were conducted in two AGS-MBRs to systematically analyze the spatiotemporal distribution patterns and driving mechanisms of ARGs. Results indicate that, among the target ARGs, sulfonamide resistance genes exhibited the highest abundance (1010-1014 copies/g dw), and ARGs exhibited significant compartmentalisation across fractions, with bottom sediments (BS) identified as a high-risk enrichment zone. Moreover, loads of ARGs in the system (1014 copies/g dw) are markedly higher than in natural environments, and enrichment zones such as BS may serve as important transmission sources during sludge disposal. Under sulfamethoxazole (SMX) stress, ARGs displayed distinct evolutionary trajectories, with different sludge components adopting different coping strategies. Quantitative PCR and PICRUSt analyses revealed AGS preferentially maintain elevated SOS response activity for self-repair, whereas other components exhibit increased horizontal gene transfer (HGT) to counter antibiotic pressure. Further analyses revealed that SMX addition altered community composition and gene co-selection patterns, shifting the potential host distribution of ARGs from polyhost to oligohost and thereby increasing the risk of multidrug resistance. Partial Least SquaresPath Modeling analysis indicated that microbial community structure and biomass were the primary drivers of ARG variation (ARGs R2 = 0.907-0.956; goodness-of-fit = 0.532-0.786). Environmental factors and SMX mainly influenced ARGs indirectly by modulating community structure and biomass. These findings provide a theoretical basis for assessing ARG transmission risk and guiding management strategies in AGS-MBR systems.

Positively charged nanofiltration (NF) membranes have demonstrated significant potential in magnesium-lithium separation, desalination, and heavy metal removal. However, traditional polyamide NF membranes have certain limitations in terms of permeability, making it difficult to meet the requirements for efficient separation. To address this challenge, we developed an advanced positively charged membrane via a swellingembedding post-treatment strategy based on conventional interfacial polymerization NF membranes. Specifically, solvent swelling was employed to tune the membrane microstructure, followed by the incorporation of quaternary ammonium compounds (benzyl vinyl trimethyl ammonium chloride, VBTA). This dual modification not only regulated the pore structure but also imparted additional positive charges to the polyamide layer. Under optimal conditions, the prepared TFC-SQA membrane exhibited a permeability of 12.67 +/- 0.61 L & sdot;m- 2 & sdot;h- 1 & sdot;bar- 1, which is three times that of the pristine TFC membrane; for a mixed solution with a Mg2+/Li+ concentration ratio of 20 and a total concentration of 2000 ppm, the separation factor SLi, Mg achieved 21.09. Additionally, the retention rates for NiCl2, ZnCl2, Cu (NO3)2, CdCl2, and PbCl2 (all at 200 ppm) were 97.69%, 96.80%, 95.73%, 94.67%, and 90.03%, respectively. Furthermore, the membrane exhibited excellent long-term stability and fouling resistance, indicating its significant potential for applications in magnesium-lithium separation in salt lakes and heavy metal treatment.

AIMS:Sulfamethoxazole (SMX) is a commonly detected antibiotic in municipal wastewater and has been reported to adversely affect biological nutrient removal processes. This study aimed to systematically investigate the physiological performance and adaptive mechanisms of Acinetobacter junii (BWFJF1), a denitrifying polyphosphate-accumulating organism (DPAO), in response to increasing SMX stress. METHODS AND RESULTS:Strain BWFJF1 was exposed to SMX concentrations ranging from 0.0 to 10.0 mg L⁻¹ to evaluate nitrogen and phosphorus removal performance and stress responses. The strain maintained stable nitrogen removal across all treatments and exhibited a marked enhancement of phosphorus removal at high SMX concentrations, challenging the conventional expectation that the metabolic cost of antibiotic resistance impairs nutrient removal. SEM-EDS analysis revealed pronounced morphological changes accompanied by increased phosphorus accumulation on the cell surface. Transcriptomic analysis showed significant upregulation of genes associated with efflux systems, phosphate transport, and energy metabolism, while metabolomic profiling indicated extensive metabolic reprogramming involving the TCA cycle, amino acid biosynthesis, and lipid remodeling. CONCLUSIONS:These findings demonstrate that Strain BWFJF1 employs an SMX-induced adaptive strategy that couples antibiotic resistance with reinforced phosphorus metabolism, thereby sustaining efficient nutrient removal under antibiotic stress.

Rare earth tailings leachate, enriched in ammonium sulfate and magnesium sulfate, poses considerable environmental challenges while representing a valuable source of recoverable resources. Herein, a selective electrodialysis (SED) process was developed for the selective separation and recovery of NH4+ and Mg2+ from nutrient-rich tailings leachate. The influences of feed concentration, concentrate-to-diluate volume ratio, and current density on ion migration, separation efficiency, permselectivity, and energy consumption were systematically examined. Increasing the current density from 5.5 to 7.5 mA cm−2 promoted NH4+ transport, resulting in an increase in NH4+ recovery from 49.1% to 90.2% and NH4+/Mg2+ permselectivity from 59 to 361. To overcome the limitations of single-stage separation, a three-stage ionic sieving configuration was subsequently implemented to enhance monovalent/divalent cation discrimination. The improved process achieved the production of high-purity (NH4)2SO4 and MgSO4 with purities of 99.8% and 97.9%, respectively. These results demonstrate that coupling selective electrodialysis with multistage ionic sieving effectively intensifies monovalent/divalent cation separation and enables efficient resource recovery from complex industrial effluents. The proposed strategy offers a promising and sustainable solution for rare earth wastewater treatment and salt valorization.

In the context of sustainable rare earth hydrometallurgy, the generated high-acid-content stripping solution represents a valuable secondary resource rather than a waste stream. Diffusion dialysis (DD) technology based on anion exchange membranes (AEMs) offers an energy-efficient and environmentally benign approach for acid recovery. However, the development of AEMs with simultaneously high acid permeability and excellent rare earth ion rejection remains a major challenge due to the intrinsic permeability-selectivity trade-off. Herein, a facile membrane fabrication strategy integrating nonsolvent-induced phase separation (NIPS) and one-step modification method is proposed to construct porous AEMs with tunable microstructure and enhanced diffusion dialysis performance. A chloromethylated polysulfone (CMPSF) porous substrate membrane was first prepared via NIPS and subsequently modified using N,N,N′,N″,N″-pentamethyldiethylenetriamine as bifunctional reagent, enabling simultaneous quaternization and crosslinking in a single step. The resulting hierarchical porous architecture, combined with a robust crosslinked ion-transport network, effectively promotes proton transport while suppressing the diffusion of rare earth ions. Consequently, the optimized porous PPSF-3 AEM exhibits an outstanding proton dialysis coefficient (40.4 × 10−3 m h−1) and an excellent proton/rare earth ion selectivity (SH+/La3+ of 3231.9), which are 9.4 times and 5.7 times higher than those of the commercial DF-120 AEM, respectively. This enhanced separation performance is attributed to the synergistic effects of increased free volume, optimized ion-conduction pathways, and strengthened Donnan exclusion arising from the tailored porous-crosslinked structure. This study provides a simple and cost-effective strategy in fabricating high-performance porous AEMs for efficient acid recovery from rare earth stripping solutions through diffusion dialysis.

This study presents an investigation into in-situ reactivation of aerobic granular sludge (AGS) within membrane bioreactors (MBR) following long-term storage. AGS was categorized into four distinct states based on microbial community similarity: before storage, after storage, before re-granulation and after re-granulation. The AGS, subjected to anaerobic and starvation conditions, showed reduced biomass, darkened color, and emitted a foul odor, with significant disintegration observed after 60 days of storage. During the restoration phase, AGS underwent re-granulation within 30 days, indicating successful activation. Notably, AGS demonstrated the ability to degrade pollutants in the early stages of restoration, with COD removal rates exceeding 95% and TN removal rates exceeding 90% in the suitable aeration state. Metagenome analysis disclosed that the stored AGS exhibited over 2.2-fold greater abundance of nitrogen fixation genes ( nifD, H, K ) than other groups, accompanied by elevated levels of phosphorus metabolism genes such as ppa, ppgK, phnN, phoB, phoR, and phoA. This indicates that AGS actively adapted its metabolic processes in response to nitrogen and phosphorus depletion during storage. This study reveals the AGS-MBR system's reactivation potential after long-term storage, confirming its ability to withstand environmental stress and rapidly regain activity, offering valuable insights for wastewater treatment and engineering applications.

g-C3N4 (CN) based catalysts were effective for photocatalytic ozonation (PCO), but their stability during reaction remained a mystery. This study investigated the change on PCO activity and stability of CN induced by F or I doping. Compared with CN, F-CN had the greater VB potential while I-CN had a greater CB position, which both led to their better O3 activation. F-CN and I-CN PCO showed the greater oxalic acid (OA) degradation than that of CN PCO process. Though the enhanced activity, both F-CN and I-CN demonstrated the lower stability compared with that of CN. Because of the existing of reactive oxygen species (ROS) like center dot OH, center dot O2- and hvb+, CN, F-CN and ICN were partially oxidized, generating NO3- and organic molecules such as cyanuric acid. hvb+ and center dot OH mainly accounted for the decomposition of three CN. Triazine ring oxidation resulted in internal tearing and edge fracture as well as the formation of O-containing groups on all CN-based catalysts. O contents in catalysts initially increased and then decreased with reaction time, indicating that surface O-containing groups were unstable. The structural destroy could be eased with the present of organic pollutants. This study deepened the understanding of fate of CN based catalysts during PCO application.

The continuous-flow aerobic granular sludge-membrane bioreactor (AGS-MBR) system represents an efficient and sustainable technology for wastewater treatment. AGS, a spherical or ellipsoidal granular sludge formed through microbial self-aggregation under aerobic conditions, progresses through four distinct life-cycle stages in the AGS-MBR system: initial, growth, mature, and cleaved. Accurate identification and classification of these stages are crucial for optimizing AGS-MBR operations and maintaining system stability; however, traditional monitoring methods are labor-intensive and error-prone. This study utilized Artificial Intelligence (AI) to develop a machine learning model based on the You Only Look Once (YOLOv8) algorithm for automated AGS monitoring and classification. Trained on 862 annotated images, the model achieved average precision of 0.985 at an Intersection over Union (IoU) threshold of 0.5 (mAP50), and the mAP50-95 of 0.837, demonstrating high accuracy in AGS classification. The t-distributed Stochastic Neighbor Embedding (t-SNE) revealed distinct clusters of AGS features across life-cycle stages, while SHapley Additive exPlanations (SHAP) demonstrated that the model focused on global features of small-grained images and edge features of large-grained images, both confirming the robustness of classification. The model's statistical functionality, supported by global variables, enabled real-time AGS monitoring in MBR system. This study provides a powerful tool for detecting and classifying the AGS life-cycle, offering guidance for the operation and maintenance of AGS-MBR system and demonstrating the potential applications of AI in wastewater treatment.

Aerobic granular sludge membrane bioreactors (AGS-MBRs) are promising for treating antibiotic-laden wastewater. However, their adaptive response to sulfamethoxazole (SMX) and associated antibiotic resistance risks remain unclear. Through a 148-day continuous-flow experiment integrated with metagenomics and metabolomics, this study investigated the impacts of SMX (0-4 mg/L) on granule structure, reactor performance, and antibiotic resistance genes (ARGs) dynamics. Under SMX exposure, phenomena including increased filamentous bacteria on the particle surface, intensified membrane fouling, reduced particle size, and improved settling performance were observed. Microbial adaptation strategies included a decrease in the protein-to-polysaccharide ratio (from 1.64 to 0.68) in extracellular polymeric substances (EPS). SMX exposure induced a trade-off in nutrient removal, significantly reducing total nitrogen (TN) removal from 90.8 % to 69.8-76.9 % while substantially enhancing total phosphorus (TP) removal from 58.3 % to 78.4-87.7 %. Metagenomics analysis linked these contrasting nutrient removal shifts to nitrogen and phosphorus metabolism genes, as well as the enrichment of polyphosphate-accumulating organisms (PAOs). SMX increased the ARG abundance (particularly sul1, sul2, and sul3) and facilitated horizontal gene transfer by upregulating relevant functional genes. Metabolomics revealed microbial preferential utilization of low-energy-cost amino acids (e.g., glutamate, aspartate) and polysaccharides for EPS synthesis under SMX stress. Furthermore, SMX upregulated ABC transporters and amino acid biosynthesis pathways, which together contribute to enhanced microbial antibiotic resistance. This study reveals an interlinked physicochemical-microbial-metabolic network driving SMX impacts in AGS-MBRs, providing actionable strategies to balance nutrient removal and mitigate detrimental effects in antibiotic wastewater treatment.

This study characterized and demonstrated the bistability (including both structural and functional stability) of aerobic granular sludge (AGS) that was self-cultivated in a continuous flow membrane bioreactor for the treatment of real municipal wastewater (50 t/d). The results indicated that the elevated Ca2+ concentrations (28.44-34.21 mg/L) led to close proximity with the extracellular polymeric substance (EPS) secreted by functional microorganisms (dominated by denitrifying polyphosphate-accumulating organisms and denitrifying glycogen-accumulating organisms in mutualistic symbiosis with other species) in the pH range of 7.1-7.3, resulting in the quick formation of AGS that was capable of maintaining the functional stability in chemical oxygen demand degradation and nutrients removal. The -OH functional group of the polysaccharide mainly in loosely bound EPS was bound to Ca2+ via electrostatic interactions, leading to gradual CaCO3 precipitation within the granules under the synergistic influence of CO2 and OH-, which enhanced the Young's modulus for improving AGS resilience. Additionally, the precipitation consisted partially of CaHPO4 or Ca3(PO4)2 in the outer layer and the protein primarily in tightly bound EPS led to an enhancement in the surface hydrophobicity of AGS due to the presence of hydrophobic group C-(C, H), which caused an increase in adhesion force and played a crucial role in enhancing the structural stability of AGS within the system.

This study aimed at developing a continuous flow membrane bioreactor (MBR) with vertical circulation for the rapid cultivation of aerobic granular sludge (AGS) and elucidating the underlying multi-mechanisms. The reactor, with its unique innovative structure, can generate a stable unidirectional vertical circulation flow state, providing an excellent environment for the formation of AGS and the removal of pollutants. The results demonstrated that a significant quantity of initial AGS was observed day 14, leading to the stabilization of system performance following AGS granulation. After generating stable AGS, the sludge system's decontamination ability significantly increased, with total nitrogen (TN) and total phosphorus (TP) removal rates rising from 62 % and 15-79 % and 77 %, respectively. The chemical oxygen demand (COD) removal rate remained above 95 % throughout the entire process. Extracellular polymeric substances (EPS) played a crucial role in maintaining the structural integrity of AGS. The presence of Bacillus in the early stages notably accelerated the aggregation of microorganisms, and microbial aggregates rapidly coalesced due to the intertwining of filamentous bacteria, forming the prototype of AGS. Initial AGS formation occurred through continuous microbial adhesion, and vertical circulation not only facilitated the transport of mixed liquor suspended solids (MLSS) between aerobic and anaerobic zones but also generated appropriate hydraulic shear forces, causing mutual friction among AGS granules, which resulted in smoother surfaces and denser structures of AGS. The novel configuration developed in this study and the findings obtained may serve as valuable references for the practical application of AGS technology.

Photocatalytic ozonation (PCO) process, as an effective water purification technology, was restrained by the low mass transfer and easy combination of photo-carriers (ecb - -hvb + ) of conventional semiconductor catalysts. To these end, this study synthesized FeOOH quantum-dots (FeOOH QDs) and boosted the PCO activity by its amorphous structure with Ibuprofen (IBP) as model pollutant. 81.5 % IBP was removed by FeOOH QDs PCO, but it was 59.1 % and 61.2 % for alpha-FeOOH and (3-FeOOH PCO, respectively. FeOOH QDs PCO performed well at alkaline environment but was easily inhibited by co-existing ions like SO42-, HCO3-, NO3-, and Cl-. Compared with those of alpha-FeOOH and (3-FeOOH, FeOOH QDs had the narrowest band gap and the lowest ecb- -hvb+ recombination, therefore, its ecb - was more favorable to activate O3 into center dot OH. Tetrahedral Fe3+ and octahedral Fe3+ co-existed on FeOOH QDs and the tetrahedral Fe3+ was more conducive to the adsorption of O3 and contributed to its better PCO activity. center dot OH was the major reactive oxygen species accounting for IBP degradation. During FeOOH QDs PCO process, 3 degradation routes were proposed basing on 13 kinds by-products. T.E.S.T. result indicated that most of the intermediates were less toxic than IBP. This study is useful for developing catalysts for PCO process.

This work established a quantitative method to access the shear stability of aerobic granular sludge (AGS) and validated its feasibility by using the mature AGS from a pilot -scale (50 tons/day) membrane bioreactor (MBR) for treating real municipal wastewater. The results showed that the changing rate ( AS ) of the peak area ( S ) of granule size distribution (GSD) exhibited an exponential relationship ( R2 >= 0.76) with the shear time ( y = a - b center dot cx), which was a suitable indicative index to reflect the shear stability of different AGS samples. The limiting granule size (LGS) was defined and proposed to characterize the equilibrium size for AGS after being sheared for a period of time, whose value in terms of Dv50 showed high correlation ( R2 = 0.92) with the parameter a . The free Ca2 + (28.44-34.21 mg/L) in the influent specifically interacted with polysaccharides (PS) in the granule's extracellular polymeric substance (EPS) as a nucleation site, thereby inducing the formation of Ca precipitation to enhance its Young's modulus, while Ca2 + primarily interacted with PS in soluble metabolic product (SMP) during the initial granulation process. Furthermore, the Young's modulus significantly affected the parameter a related to shear stability ( R2 = 0.99). Since the parameter a was more closely related ( R2 = 1.00) to AS than that of the parameter b or c , the excellent correlation ( R2 = 0.99) between the parameter a and the wet density further verified the feasibility of this method. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

This study aimed at identifying the key influencing factors impacting the formation and development of membrane fouling in a continuous flow aerobic granular sludge membrane bioreactor (AGS-MBR). The results indicated that the growth rate of membrane fouling (expressed as trans-membrane pressure (TMP) growth rate) exhibited significant variability over time, with the growth rates ranging from the maximum value (78.99 kPa center dot da(-1)) to the minimum (0.12 kPa center dot da(-1)). The properties of extracellular polymeric substances (EPS), floc sludge, cake layer, and AGS, particularly the ratio of protein to polysaccharide content (PN/PS), significantly influenced the formation and development of membrane fouling. The mechanisms primarily involved influencing surface hydrophilicity, altering surface potential, and affecting the physical strength of biofilm on membrane surface. The results regarding microbial community structure demonstrated that microorganisms in the reactor underwent significant community succession following sludge inoculation. The cake layer generally exhibited a richer species composition than that in floc sludge, while AGS had a dominant species composition distinct from that of other samples. Notably, as illustrated by the obtained results and the related analyses, maintaining a higher proportion of AGS inside the system is an effective strategy for slowing the formation and development of membrane fouling.

Detection of microplastics (MPs) in various water environments raises significant environmental concerns. However, comprehension of the differences in MPs and their linked biological communities across diverse water settings remains limited. This study explores MPs and their linked microbial communities in the Dongjiang River, Xingfengjiang Reservoirs, and Dayawan Bays watersheds. Our results revealed distinct community compositions of MPs in these three water environments, with higher abundance and diversity integrated index of MPs (p < 0.01) observed in rivers and reservoirs compared to bays. Significant variations in dominant microbial communities and relative abundances were observed among these water bodies, with rivers showing higher Shannon and Simpson indexes than reservoirs and bays. The co-occurrence network analysis indicated more complex and interconnected structures between bacterial communities and MPs in rivers and reservoirs than in bays. Risk assessments conducted for these water environments revealed varying levels of potential risks associated with MPs, with reservoirs posing higher risks than rivers and bays. Noteworthy differences in pathogenic bacteria composition were also identified across the water environments. This study highlights the disparities and connections between MPs and microbial communities in rivers, reservoirs, and bays, providing valuable insights for managing and mitigating MP pollution in diverse aquatic environments.

This study aimed to unveil the functional genes associated with phosphorus metabolism and to elucidate the transformation behavior and removal mechanism of phosphorus from municipal wastewater in a continuous flow aerobic granular sludge (AGS)-membrane bioreactor (MBR). By conducting a comparative analysis of varying concentrations of carbon sources and patterns of sludge discharge, the removal efficiency and distribution patterns of phosphorus, as well as the microbial community structure within the utilized system, were thoroughly examined. Additionally, an in-depth investigation was conducted for revealing the principal metabolic pathways and enzyme gene counts associated with phosphate-accumulating organisms (PAOs). The results indicates that during the initial operation phase, the phosphorus removal performance reaches 70%. However, a significant change in phosphorus removal performance occurred when reducing carbon source concentration and initiating sludge discharge. In AGS, the TP was maintained at 80-87.9 mg/L, which was significantly higher than that in floc sludge (FS), and extracellular polymeric substances (EPS) play a crucial role in storing and transforming phosphorus. The TP in TB-EPS reached 7.12-9.12 mg/L, which constituted the largest proportion in EPS. Macrogenome sequencing revealed multiple pathways for metabolic phosphorus removal in PAOs, including glycolysis, the tricarboxylic acid (TCA) cycle, and the Embden-Meyerhoff pathway (EMP). Each of these pathways provides adenosine-triphosphate (ATP) and reducing power for polyhydroxyalkanoate (PHA) synthesis by PAOs. The counts of phosphorous-removing microorganisms and genes were influenced by different carbon-tophosphorous ratios. Furthermore, the findings reveal various roles played by different functional genes in PAO's phosphorus metabolism within their respective metabolic pathways, which contribute to both the distribution and transformation processes of phosphorous.

The present study aimed to prepare an aluminum-based nanoflower (Al-NF) adsorbent using wasted aluminum polishing solution as raw materials, which effectively isolated the residues of anti-epidemic related drugs (lopinavir (LPV) and ciprofloxacin (CIP)) from wastewater. A comprehensive characterization approach involving SEM, XRD, BET, TGA, FTIR, and XPS was employed to investigate the adsorption capacity and mechanism of Al-NF towards LPV and CIP. The results revealed that the adsorption process involved both homogeneous and non-homogeneous interactions between the LPV/CIP molecules and the Al-NF surface. According to the Langmuir model calculations, the maximum adsorption capacities of Al-NF for LPV and CIP at 293.15 K were determined to be 32.41 mg/g and 14.43 mg/g, respectively, while their adsorption kinetics followed a pseudo-second-order model more appropriately. Furthermore, the spontaneous exothermic nature of LPV/CIP adsorption on Al-NF was confirmed by thermodynamic analysis. The mechanism investigations indicated that hydrogen bonding, electrostatic interaction, pi-pi bonding interaction, as well as n-pi EDA bonding collectively contributed to the overall adsorption process on the Al-NF surface for both LPV and CIP species. Additionally, the reusability demonstrated by Al-NF highlights its potential as a promising low-cost material for removing antiepidemic related drug residues from wastewater utilizing industrial hazardous wastes.

Immobilized fillers have been increasingly utilized in biotrickling filters (BTFs) due to their positive impact on shock load resistance and recovery performance. However, due to the inherent characteristics of its immobilized carrier, the immobilized filler is prone to swelling during the long-term operation of the system, resulting in increased pressure drop. Polyurethane (PU) sponge was used as the cross-linked skeleton of immobilized filler and compared with direct emulsified cross-linked immobilized filler for treating ethylbenzene gas. In the early stage, both fillers can maintain good performance despite changes in the inlet concentration and short-term stagnation. However, on the 107th day of operation, the immobilized filler experienced swelling, and the pressure drop sharply increased to 137.2 Pa, while the PU immobilized filler was still able to maintain a low-pressure drop level. The results of the microbial diversity analysis revealed that the microbial community structure of PU immobilized fillers remained relatively stable when responding to the fluctuations in operating conditions. PU sponges as the skeleton can effectively prolong the service life of the immobilized filler and improve the performance of the biotrickling filter.