查看更多>>摘要：Currently,the most cost-effective and efficient method for phosphorus(P)removal from wastewater is enhanced biological P removal(EPBR)via polyphosphate-accumulating organisms(PAOs).This study integrates a literature review with genomic analysis to uncover the phylogenetic and metabolic diversity of the relevant PAOs for wastewater treatment.The findings highlight significant differences in the metabolic capabilities of PAOs relevant to wastewater treatment.Notably,Candidatus Dechloromonas and Candidatus Accumulibacter can synthesize polyhydroxyalkanoates,possess specific enzymes for ATP production from polyphosphate,and have electrochemical transporters for acetate and C4-dicarboxylates.In contrast,Tetrasphaera,Candidatus Phosphoribacter,Knoellia,and Phycicoccus possess PolyP-glucokinase and electrochemical transporters for sugars/amino acids.Additionally,this review explores various detection methods for polyphosphate and PAOs in activated sludge wastewater treat-ment plants.Notably,FISH-Raman spectroscopy emerges as one of the most advanced detection tech-niques.Overall,this review provides critical insights into PAO research,underscoring the need for enhanced strategies in biological phosphorus removal.
查看更多>>摘要：Accurately predicting the concentration of fine particulate matter(PM2.5)is crucial for evaluating air pollution levels and public exposure.Recent advancements have seen a significant rise in using deep learning(DL)models for forecasting PM2.5 concentrations.Nonetheless,there is a lack of unified and standardized frameworks for assessing the performance of DL-based PM2.5 prediction models.Here we extensively reviewed those DL-based hybrid models for forecasting PM2.5 levels according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines.We examined the similarities and differences among various DL models in predicting PM2.5 by comparing their complexity and effectiveness.We categorized PM2.5 DL methodologies into seven types based on per-formance and application conditions,including four types of DL-based models and three types of hybrid learning models.Our research indicates that established deep learning architectures are commonly used and respected for their efficiency.However,many of these models often fall short in terms of innovation and interpretability.Conversely,models hybrid with traditional approaches,like deterministic and sta-tistical models,exhibit high interpretability but compromise on accuracy and speed.Besides,hybrid DL models,representing the pinnacle of innovation among the studied models,encounter issues with interpretability.We introduce a novel three-dimensional evaluation framework,i.e.,Dataset-Method-Experiment Standard(DMES)to unify and standardize the evaluation for PM2.5 predictions using DL models.This review provides a framework for future evaluations of DL-based models,which could inspire researchers to standardize DL model usage in PM2.5 prediction and improve the quality of related studies.
查看更多>>摘要：Zero-valent iron(ZVI),an ideal reductant treating persistent pollutants,is hampered by issues like corrosion,passivation,and suboptimal utilization.Recent advancements in nonmetallic modified ZVI(NM-ZVI)show promising potential in circumventing these challenges by modifying ZVI's surface and internal physicochemical properties.Despite its promise,a thorough synthesis of research advancements in this domain remains elusive.Here we review the innovative methodologies,regulatory principles,and reduction-centric mechanisms underpinning NM-ZVI's effectiveness against two prevalent persistent pollutants:halogenated organic compounds and heavy metals.We start by evaluating different nonmetallic modification techniques,such as liquid-phase reduction,mechanical ball milling,and py-rolysis,and their respective advantages.The discussion progresses towards a critical analysis of current strategies and mechanisms used for NM-ZVI to enhance its reactivity,electron selectivity,and electron utilization efficiency.This is achieved by optimizing the elemental compositions,content ratios,lattice constants,hydrophobicity,and conductivity.Furthermore,we propose novel approaches for augmenting NM-ZVI's capability to address complex pollution challenges.This review highlights NM-ZVI's potential as an alternative to remediate water environments contaminated with halogenated organic compounds or heavy metals,contributing to the broader discourse on green remediation technologies.
查看更多>>摘要：Chlorinated organic pollutants constitute a significant category of persistent organic pollutants due to their widespread presence in the environment,which is primarily attributed to the expansion of agri-cultural and industrial activities.These pollutants are characterized by their persistence,potent toxicity,and capability for long-range dispersion,emphasizing the importance of their eradication to mitigate environmental pollution.While conventional methods for removing chlorinated organic pollutants encompass advanced oxidation,catalytic oxidation,and bioremediation,the utilization of biochar has emerged as a prominent green and efficacious method in recent years.Here we review biochar's role in remediating typical chlorinated organics,including polychlorinated biphenyls(PCBs),triclosan(TCS),trichloroethene(TCE),tetrachloroethylene(PCE),organochlorine pesticides(OCPs),and chlorobenzenes(CBs).We focus on the impact of biochar material properties on the adsorption mechanisms of chlori-nated organics.This review highlights the use of biochar as a sustainable and eco-friendly method for removing chlorinated organic pollutants,especially when combined with biological or chemical stra-tegies.Biochar facilitates electron transfer efficiency between microorganisms,promoting the growth of dechlorinating bacteria and mitigating the toxicity of chlorinated organics through adsorption.Furthermore,biochar can activate processes such as advanced oxidation or nano zero-valent iron,generating free radicals to decompose chlorinated organic compounds.We observe a broader application of biochar and bioprocesses for treating chlorinated organic pollutants in soil,reducing environmental impacts.Conversely,for water-based pollutants,integrating biochar with chemical methods proved more effective,leading to superior purification results.This review contributes to the theoretical and practical application of biochar for removing environmental chlorinated organic pollutants.
查看更多>>摘要：Plastic waste discarded into aquatic environments gradually degrades into smaller fragments,known as microplastics(MPs),which range in size from 0.05 to 5 mm.The ubiquity of MPs poses a significant threat to aquatic ecosystems and,by extension,human health,as these particles are ingested by various marine organisms including zooplankton,crustaceans,and fish,eventually entering the human food chain.This contamination threatens the entire ecological balance,encompassing food safety and the health of aquatic systems.Consequently,developing effective MP removal technologies has emerged as a critical area of research.Here,we summarize the mechanisms and recently reported strategies for removing MPs from aquatic ecosystems.Strategies combining physical and chemical pretreatments with microbial degradation have shown promise in decomposing MPs.Microorganisms such as bacteria,fungi,algae,and specific enzymes are being leveraged in MP remediation efforts.Recent advancements have focused on innovative methods such as membrane bioreactors,synthetic biology,organosilane-based techniques,biofilm-mediated remediation,and nanomaterial-enabled strategies,with nano-enabled technologies demonstrating substantial potential to enhance MP removal efficiency.This review aims to stimulate further innovation in effective MP removal methods,promoting environmental and social well-being.
查看更多>>摘要：In-channel vegetation is ubiquitous in aquatic environments and plays a critical role in the fate and transport of solutes and particles in aquatic ecosystems.Recent studies have advanced our under-standing of the role of vegetation in solute flow and particle transport in aquatic ecosystems.This review summarizes these papers and discusses the impacts of emergent and rigid vegetation on the surface flow,the advection and dispersion of solutes,suspended load transport,bedload transport,and hypo-rheic exchange.The two competing effects of emergent vegetation on the above transport processes are discussed.On the one hand,emergent vegetation reduces mean flow velocity at the same surface slope,which reduces mass transport.On the other hand,at the same mean flow velocity,vegetation generates turbulence,which enhances mass transport.Mechanistic understanding of these two competing effects and predictive equations derived from laboratory experiments are discussed.Predictive equations for the mean flow velocity and turbulent kinetic energy inside an emergent vegetation canopy are derived based on force and energy balance.The impacts of emergent vegetation on the advection-dispersion process,the suspended load and bedload transport,and the hyporheic exchange are summarized.The impacts of other vegetation-related factors,such as vegetation morphology,submergence,and flexibility,are briefly discussed.The role of vegetation in transporting other particles,such as micro-and macro-plastics,is also briefly discussed.Finally,suggestions for future research directions are proposed to advance the understanding of the dynamic interplays among natural vegetation,flow dynamics,and sedimentary processes.
查看更多>>摘要：Activated carbon is employed for the adsorption of organic micropollutants(OMPs)from water,typically present in concentrations ranging from ng L-1 to μg L-1.However,the efficacy of OMP removal is considerably deteriorated due to competitive adsorption from background dissolved organic matter(DOM),present at substantially higher concentrations in mg L-1.Interpreting the characteristics of competitive DOM is crucial in predicting OMP adsorption efficiencies across diverse natural waters.Molecular weight(MW),aromaticity,and polarity influence DOM competitiveness.Although the aromaticity-related metrics,such as UV254,of low MW DOM were proposed to correlate with DOM competitiveness,the method suffers from limitations in understanding the interplay of polarity and aromaticity in determining DOM competitiveness.Here,we elucidate the intricate influence of aroma-ticity and polarity in low MW DOM competition,spanning from a fraction level to a compound level,by employing direct sample injection liquid chromatography coupled with ultrahigh-resolution Fourier-transform ion cyclotron resonance mass spectrometry.Anion exchange resin pre-treatment eliminated 93％of UV254-active DOM,predominantly aromatic and polar DOM,and only minimally alleviated DOM competition.Molecular characterization revealed that nonpolar molecular formulas(constituting 26％PAC-adsorbable DOM)with medium aromaticity contributed more to the DOM competitiveness.Isomer-level analysis indicated that the competitiveness of highly aromatic LMW DOM compounds was strongly counterbalanced by increased polarity.Strong aromaticity-derived π-π interaction cannot facilitate the competitive adsorption of hydrophilic DOM compounds.Our results underscore the constraints of depending solely on aromaticity-based approaches as the exclusive interpretive measure for DOM competitiveness.In a broader context,this study demonstrates an effect-oriented DOM analysis,eluci-dating counterbalancing interactions of DOM molecular properties from fraction to compound level.
查看更多>>摘要：Recent advancements in constructed wetlands(CWs)have highlighted the imperative of enhancing nitrogen(N)removal efficiency.However,the variability in influent substrate concentrations presents a challenge in optimizing N removal strategies due to its impact on removal efficiency and mechanisms.Here we show the interplay between influent substrate concentration and N removal processes within integrated vertical-flow constructed wetlands(IVFCWs),using wastewaters enriched with NO3--N and NH4+-N at varying carbon to nitrogen(C/N)ratios(1,3,and 6).In the NO3--N enriched systems,a positive correlation was observed between the C/N ratio and total nitrogen(TN)removal efficiency,which markedly increased from 13.46±2.23％to 87.00±2.37％as the C/N ratio escalated from 1 to 6.Conversely,in NH4+-N enriched systems,TN removal efficiencies in the A-6 setup(33.69±4.83％)were marginally 1.25 to 1.29 times higher than those in A-3 and A-1 systems,attributed to constraints in dissolved oxygen(DO)levels and alkalinity.Microbial community analysis and metabolic pathway assessment revealed that anaerobic denitrification,microbial N assimilation,and dissimilatory nitrate reduction to ammonium(DNRA)predominated in NO3--N systems with higher C/N ratios(C/N ≥ 3).In contrast,aerobic denitrification and microbial N assimilation were the primary pathways in NH4+-N systems and low C/N NO3--N systems.A mass balance approach indicated denitrification and microbial N assimilation contributed 4.12-47.12％and 8.51-38.96％in NO3--N systems,respectively,and 0.55-17.35％and 7.83-33.55％in NH4+-N systems to TN removal.To enhance N removal,strategies for NO3--N domi-nated systems should address carbon source limitations and electron competition between denitrifica-tion and DNRA processes,while NH4+-N dominated systems require optimization of carbon utilization pathways,and ensuring adequate DO and alkalinity supply.
查看更多>>摘要：Antibiotic resistance is an escalating global health concern,exacerbated by the pervasive presence of antibiotic resistance genes(ARGs)in natural environments.The Yangtze River,the world's third-longest river,traversing areas with intense human activities,presents a unique ecosystem for studying the impact of these genes on human health.Here,we explored ARGs in the Yangtze River,examining 204 samples from six distinct habitats of approximately 6000 km of the river,including free-living and particle-associated settings,surface and bottom sediments,and surface and bottom bank soils.Employing shotgun sequencing,we generated an average of 13.69 Gb reads per sample.Our findings revealed a significantly higher abundance and diversity of ARGs in water-borne bacteria compared to other habitats.A notable pattern of resistome coalescence was observed within similar habitat types.In addition,we developed a framework for ranking the risk of ARG and a corresponding method for calculating the risk index.Applying them,we identified water-borne bacteria as the highest contributors to health risks,and noted an increase in ARG risks in particle-associated bacteria correlating with heightened anthropogenic activities.Further analysis using a weighted ARG risk index pinpointed the Chengdu-Chongqing and Yangtze River Delta urban agglomerations as regions of elevated health risk.These insights provide a critical new perspective on ARG health risk assessment,highlighting the urgent need for strategies to mitigate the impact of ARGs on human health and to preserve the ecological and economic sustainability of the Yangtze River for future human use.
查看更多>>摘要：The evasion of carbon dioxide(CO2)from lakes significantly influences the global carbon equilibrium.Amidst global climatic transformations,the role of Qingzang Plateau(QZP)lakes as carbon(C)sources or sinks remains a subject of debate.Furthermore,accurately quantifying their contribution to the global carbon budget presents a formidable challenge.Here,spanning half a century(1970-2020),we utilize a synthesis of literature and empirical field data to assess the CO2 exchange flux of QZP lakes.We find markedly higher CO2 exchange flux in the southeast lakes than that in the northern and western regions from 1970 to 2000.During this time,both freshwater and saltwater lakes served primarily as carbon sources.The annual CO2 exchange flux was estimated at 2.04±0.37 Tg(Tg)C yr-1,mainly influenced by temperature fluctuations.The CO2 exchange flux patterns underwent a geographical inversion between 2000 and 2020,with increased levels in the west and decreased levels in the east.Notably,CO2 emissions from freshwater lakes diminished,and certain saltwater lakes in the QTP transitioned from carbon sources to sinks.From 2000 to 2020,the annual CO2 exchange flux from QZP lakes is estimated at 1.34±0.50 Tg C yr-1,with solar radiation playing a more pronounced role in carbon emissions.Cumulatively,over the past five decades,QZP lakes have generally functioned as carbon sources.Nevertheless,the total annual CO2 emissions have declined since the year 2000,indicating a potential shift trend from being a carbon source to a sink,mirroring broader patterns of global climate change.These findings not only augment our understanding of the carbon cycle in plateau aquatic systems but also provide crucial data for refining China's carbon budget.
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