Journal of contaminant hydrology最新文献

{"title":"Integrated enviro-economic optimization of solar-powered electrocoagulation for sustainable nitrate removal from groundwater","authors":"Benan Yazıcı Karabulut ,&nbsp;Fatma Didem Alay ,&nbsp;Fatma Zuhal Adalar","doi":"10.1016/j.jconhyd.2025.104745","DOIUrl":"10.1016/j.jconhyd.2025.104745","url":null,"abstract":"<div><div>This study investigates the use of machine learning (ML) models—Linear Regression (LR), Support Vector Regression (SVR), Gradient Boosting (GB), K-Nearest Neighbour (KNN), Random Forest (RF), Artificial Neural Network (ANN), Multilayer Perceptron Regressor (MLPR), and Decision Tree (DT)—to optimize and predict energy consumption in the electrocoagulation (EC) process for nitrate (NO₃⁻) removal from groundwater. Alongside these data-driven approaches, Response Surface Methodology (RSM) with a Box-Behnken design (BBD) was applied to statistically evaluate the operational parameters. Among the tested models, the GB model showed the best performance with R² = 0.9924, Mean Squared Error (MSE) = 0.0135, Root Mean Squared Error (RMSE) = 0.1164 and Mean Absolute Percentage Error (MAPE) = 8.7418. Optimal operating conditions were identified to achieve NO₃⁻ removal below permissible limits. The specific energy consumption under these conditions corresponds to operational costs of 0.46, 0.55, and 0.25 $/m³ for Al, Fe, and Al/Fe combination electrodes, respectively. These results indicate that EC powered by photovoltaic energy (PV) can serve as a sustainable and decentralized solution for groundwater treatment in rural areas, offering both high removal efficiency and economically favourable operation.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"276 ","pages":"Article 104745"},"PeriodicalIF":4.4,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Field application of bioelectrochemical reduction technology for treating hexavalent chromium in groundwater","authors":"Yuehua Li ,&nbsp;Dianchao Kong ,&nbsp;Kylan Jin ,&nbsp;Xianbin Dong ,&nbsp;Qiang Zhang ,&nbsp;Liang Chen","doi":"10.1016/j.jconhyd.2025.104744","DOIUrl":"10.1016/j.jconhyd.2025.104744","url":null,"abstract":"<div><div>Hexavalent chromium [Cr(VI)] is one of the most prevalent contaminants in groundwater. Contemporary in situ remediation approaches, such as chemical reduction, chemical immobilization, and biological reduction, have been widely implemented at various contaminated sites. However, these “contact-based” technologies tend to be restricted by matrix of tight lithology such as clay and fractured bedrocks. Electrochemical techniques can overcome such impedes due to its working mechanism based on electron transport. In this pilot study, a commercialized bioelectrochemical reduction (BECR) technology (trademarked as <em>E</em>-Redox®-R by Advanced Environmental Technologies, LLC, Colorado, USA) was applied at a Cr(VI)-contaminated site in Henan Province, China, to remediate chromium contamination in groundwater. This project represents the first field application of the BECR technology in Mainland China for Cr(VI) treatment. The BECR pilot system consisted of four units, comprising 12 electrodes installed across a 38.5-m transect. For each unit, one anode well and two cathode wells were arranged in an isosceles triangle configuration, with an inter-electrode spacing of 5.5 m. Within 10 months of system operation, groundwater Cr(VI) concentrations in the cathode wells ranging from 0.3 mg/L to 46.5 mg/L decreased by 24 % to 99 % despite potential masking effects by the desorption of chromium mass from the soil matrix into the aqueous phase. Within the treatment zone, Cr(VI) concentrations in the two upgradient monitoring wells located near the anode electrodes decreased by 21 % and 42 %, respectively, while concentrations in the three downgradient monitoring-compliance wells near the cathode electrodes decreased by 65 % to 96 %. These results indicate that the BECR technology can effectively reduce Cr(VI) in the subsurface and holds promise as a sustainable in situ technology for remediating chromium and other contaminants impacted groundwater.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"276 ","pages":"Article 104744"},"PeriodicalIF":4.4,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Analytic Element Method solution for simulating multiple steady-state groundwater contamination scenarios","authors":"Anton V. Köhler ,&nbsp;James R. Craig ,&nbsp;Prabhas K. Yadav ,&nbsp;Rudolf Liedl","doi":"10.1016/j.jconhyd.2025.104733","DOIUrl":"10.1016/j.jconhyd.2025.104733","url":null,"abstract":"<div><div>This paper presents a new Analytic Element Method (AEM) model for a 2D reactive transport problem. The AEM approach offers domain complexity due to superposition of multiple boundary conditions, while minimizing computational efforts, being a grid-free method. For the solution development, transformations of the advection–dispersion–reaction (ADR) equation are applied resulting in an equivalent mathematical problem governed by the modified Helmholtz equation. A solution (infinite series of Mathieu functions) derived for circular source elements provides the steady-state concentration distribution of two compounds undergoing an instantaneous and binary reaction in uniform flow. The solution is verified with an absolute error of the order <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>7</mn></mrow></msup></mrow></math></span> mg/l and a relative error of order <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math></span> along boundary conditions. A sensitivity analysis identifies source strength and utilization factor of the reactants as parameters with the strongest impact on the plume length. The practicality of the developed AEM model is illustrated using different conceptual scenarios in which multiple source elements are superimposed as co- and counter interacting sources. Additionally, the method of images is applied using the same solution for representing the vertically oriented domain. These highlight the potential of the developed model for simulating a variety of practical conditions, such as irregular source geometries with or without continuity with unrestricted domain extent and minimal computational effort. Further, three field sites are briefly evaluated to present the applicability of the model.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"276 ","pages":"Article 104733"},"PeriodicalIF":4.4,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrating nitrate isotopes and organic contaminants of emerging concern to improve untreated wastewater tracing in urban groundwater","authors":"W. Ben Nasr ,&nbsp;R. Trabelsi ,&nbsp;K. Zouari ,&nbsp;K. Khmila ,&nbsp;F. Huneau","doi":"10.1016/j.jconhyd.2025.104742","DOIUrl":"10.1016/j.jconhyd.2025.104742","url":null,"abstract":"<div><div>Untreated wastewater represents a major source of groundwater contamination in urban contexts with inadequate sanitation strategies. Identifying the origins and subsurface pathways of this contamination is essential for effective groundwater management, yet it remains challenging in environments influenced by multiple anthropogenic inputs. Although nitrate isotopes (δ¹⁵N-NO₃⁻, δ¹⁸O-NO₃⁻) are commonly used to trace contamination sources, they have their own limitations for distinguishing overlapping isotopic signatures, including those of wastewater and manure, or a mixture of untreated and treated wastewater inputs. A multi-tracer approach combining hydrogeochemical, isotopic and organic tools were used to accurately delineate wastewater impacts in mixed urban/peri-urban environments. Increasing nitrate concentrations in urban environments were attributed to an active anthropogenic stress, arising from population growth and widespread use of rudimentary on-site sanitation systems (soak-pits). Nitrate isotopes preliminarily confirmed that septic waste as the main source of pollution, but were unable to differentiate untreated wastewater inputs. In peri-urban settings, the potential interaction of domestic and agricultural influences in a heterogeneous residential landscape further complicated the interpretation of contamination processes. A strong correlation of acesulfame concentrations, a nearly ideal wastewater co-tracer, with those of labile and ubiquitous markers (saccharin, cotinine) indicated widespread contamination by recent untreated wastewater. The occurrence of non-ubiquitous pharmaceuticals confirmed the punctual impact of on-site sanitation systems. The sporadic detection of acesulfame in peri-urban areas underlines their vulnerability to man-made influences. The complementarity of nitrate isotopes and organic contaminants has significantly improved our ability to accurately identify the sources and timing of untreated wastewater inputs.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"276 ","pages":"Article 104742"},"PeriodicalIF":4.4,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stability and transformation of neptunium (Np) species under geological disposal conditions of high-level radioactive waste (HLW)","authors":"Nan Li ,&nbsp;Xianzhe Duan ,&nbsp;Nadia Cheemaa ,&nbsp;Hafiza Tasneem Nazish ,&nbsp;Guowen Peng","doi":"10.1016/j.jconhyd.2025.104739","DOIUrl":"10.1016/j.jconhyd.2025.104739","url":null,"abstract":"<div><div>Neptunium (Np) is a key radionuclide in high-level radioactive waste (HLW), and its speciation in groundwater directly affects the long-term safety of geological disposal systems. Beishan, Gansu Province, China, is the preferred site for geological disposal of HLWs in China. The weakly alkaline and carbonate-rich groundwater in this region may significantly influence the speciation and migration behavior of Np. This study uses PHREEQC software, incorporating the latest thermodynamic data from NEA-TDB and ThermoChimie databases, to systematically simulate the stability of Np species in deep groundwater of Xinchang in Beishan. It also examines how pH, Eh, temperature, and concentration of major inorganic ligands (e.g., CO₃²⁻, SO₄²⁻, F⁻,) affect Np speciation. The main findings are as follows: (1) Under representative groundwater conditions in Beishan (pH = 8.25), Np primarily exists as KNpO₂CO₃ (92.84 %) and NpO₂OH (2.34 %); (2) pH significantly regulates the species transformation of Np. In strongly acidic environments (pH = 2–4), NpF₂²⁺ and NpF₄ dominate, whereas in weakly alkaline environments (pH = 6–9), KNpO₂CO₃ competes with Np(OH)₄. In highly alkaline environments (pH &gt; 9), Np₂O₅ gradually stabilizes; (3) Changes in oxidation-reduction potential (pe) affect the valence state transformation of Np. Low pe (pe = −5 to −2) favors Np(IV) hydrolysis products, while high pe (pe &gt; 1) stabilizes Np(V) carbonate complexes; (4) Elevated temperatures (30–80 °C) enhance the oxidation and hydrolysis of Np(V), increasing concentrations of Np₂O₅, NpO₂OH, and NpO₂CO₃⁻; (5) CO₃²⁻ has the most significant effect on Np speciation, while SO₄²⁻, Cl⁻, and F⁻ have limited impacts due to their lower chelating abilities or concentrations. The Eh-pH predominance diagram indicates that weakly alkaline, reducing environments are most effective in inhibiting Np migration. This study provides valuable theoretical support for the optimization and long-term safety assessment of the HLW geological disposal site, highlighting the importance of multi-factor coupling in environmental behavior of Np.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"276 ","pages":"Article 104739"},"PeriodicalIF":4.4,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145206482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electron beam-persulfate system effectively reduces polycyclic aromatic hydrocarbons and Cr(VI) emissions: Environmental matrix impact and mechanism analysis","authors":"Lei Chen ,&nbsp;Yun Wang ,&nbsp;Haiyang Shao ,&nbsp;Jun Wang ,&nbsp;Minghong Wu ,&nbsp;Gang Xu","doi":"10.1016/j.jconhyd.2025.104738","DOIUrl":"10.1016/j.jconhyd.2025.104738","url":null,"abstract":"<div><div>Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) are prevalent pollutants in the environment, and their intricate interactions amplify the challenges of remediating complex contaminations. There is an urgent need for effective methods to treat these composite pollutants. This study innovatively demonstrates that the electron beam-persulfate system can effectively remove PAHs and reduce heavy metals. Compared to the sole use of electron beam irradiation, the degradation rate of naphthalene in the electron beam-persulfate system increased by 2.5 times, and the reduction efficiency for hexavalent chromium reached 97.6 %. In comparison with persulfate alone, the treatment efficiency of the electron beam-persulfate system for NAP increased by 8 times, achieving complete degradation at 10 kGy, with the degradation process conforming to pseudo-first-order kinetics. The experimental results indicate that the electron beam-persulfate system is a stable operational system, with pH, liquid depth, types and concentrations of inorganic ions exerting a minor influence on the system. Experimental analysis confirmed that hydroxyl and sulfate radicals play vital roles in PAH removal, while hydrated electrons and sulfate radicals are crucial for the reduction of heavy metals. Toxicity analysis also revealed that the electron beam-persulfate system achieves harmless treatment of complex pollutants. Therefore, the electron beam-persulfate system offers an efficient technology that maintains stability in various environments, providing novel pathways and methods for pollutant removal.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"276 ","pages":"Article 104738"},"PeriodicalIF":4.4,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145206510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the applicability of the soil and water assessment tool–deep learning hybrid model for predicting total nitrogen loads in a mixed agricultural watershed","authors":"Dae Seong Jeong ,&nbsp;Heewon Jeong ,&nbsp;Joon Ha Kim ,&nbsp;Do Hyuk Kwon ,&nbsp;Jin Hwi Kim ,&nbsp;Yongeun Park","doi":"10.1016/j.jconhyd.2025.104737","DOIUrl":"10.1016/j.jconhyd.2025.104737","url":null,"abstract":"<div><div>Soil and Water Assessment Tool (SWAT) is a widely used process-based watershed model for simulating hydrology and water quality under varying land use and climate conditions. Its performance relies heavily on effective calibration and validation to achieve accurate parameterization. However, these processes are often time-consuming and subject to considerable uncertainty. Multi-site calibration has been introduced to address the spatial limitations of conventional single-site calibration, yet it remains resource-intensive and may introduce inconsistencies among subbasins. To overcome these challenges, this study proposes SWAT-deep learning (DL) hybrid models for predicting total nitrogen (TN) loads in a mixed agricultural watershed. Specifically, the objective was to evaluate whether DL models trained at the watershed outlet using uncalibrated SWAT outputs could generalize effectively to upstream subbasins, thereby bypassing the need for calibration. Two hybrid models, SWAT-Long Short-Term Memory (LSTM) and SWAT-Gated Recurrent Unit (GRU), were constructed using uncalibrated SWAT simulations and precipitation data. Both hybrid models consistently outperformed the multi-site calibrated SWAT model. The SWAT-LSTM model demonstrated higher sensitivity in capturing sharp TN peaks during rainfall events, whereas the SWAT-GRU model provided more stable predictions across post-peak and recovery periods. Feature importance analysis further revealed distinct dependencies on hydrological and water quality variables. In addition, the SWAT-DL hybrid framework yielded a substantial practical advantage, achieving a more than a tenfold gain in computational efficiency over multi-site SWAT calibration while sustaining high accuracy. By reducing calibration demands without compromising accuracy and transferability, this hybrid approach represents a scalable and resource-efficient alternative for watershed-scale water quality modeling.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"276 ","pages":"Article 104737"},"PeriodicalIF":4.4,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145212713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nutrient removal characteristics of the bioretention cell under high concentration glyphosate stress","authors":"Qianhe Xia ,&nbsp;Jiaqing Xiong ,&nbsp;Jiajia Zhou ,&nbsp;Tuanping Hu ,&nbsp;Qionghua Zhang ,&nbsp;Yanzheng Liu","doi":"10.1016/j.jconhyd.2025.104735","DOIUrl":"10.1016/j.jconhyd.2025.104735","url":null,"abstract":"<div><div>The pesticide glyphosate is widely used in agriculture and is frequently detected in the natural environment. However, the effect of glyphosate in stormwater runoff on the nutrient removal efficiency of bioretention cells remains unclear. Coal- and zeolite-modified bioretention cells were constructed in this study, and their ammonia‑nitrogen (NH₄⁺-N) removal efficiency was inhibited at the beginning of glyphosate stress. In the late stage of the stress test, the NH₄⁺-N removal efficiency gradually recovered to &gt;90 %, the concentration of nitrate nitrogen (NO₃⁻-N) was stable at 10–15 mg/L, and the concentration of nitrite‑nitrogen (NO₂⁻-N) was stable at 0.05–1.81 mg/L. Glyphosate negatively impacted nitrogen removal performance. The total nitrogen (TN) concentration also increased, and its removal efficiency decreased to &lt;10 %. Total phosphorus (TP) concentrations during the initial rainfall event were significantly correlated with glyphosate concentrations (<em>p</em> &lt; 0.01), with effluent TP reaching a maximum of 121 mg/L. In the late stage of the stress test, the phosphorus removal capacity of the bioretention cell gradually recovered. The relative abundance of glyphosate-tolerant bacteria and dominant decomposition bacteria increased, while the abundance of some denitrifying functional bacteria decreased under stress, ultimately affecting the water purification effect of the bioretention cell. In summary, glyphosate stress reduced the nitrogen and phosphorus removal in the bioretention cell; the phosphorus removal capacity gradually recovered, but nitrogen removal remained inhibited.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"276 ","pages":"Article 104735"},"PeriodicalIF":4.4,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparing the variable flow velocity advection-dispersion model with the continuous time random walk model: Insights from a soil column salt transport experiment","authors":"Xianmeng Meng ,&nbsp;Qu Wang ,&nbsp;Maosheng Yin ,&nbsp;Xiaoxuan Liu ,&nbsp;Dengfeng Liu","doi":"10.1016/j.jconhyd.2025.104736","DOIUrl":"10.1016/j.jconhyd.2025.104736","url":null,"abstract":"<div><div>The transport of salt in low-permeability media can significantly alter permeability. To investigate the impact of permeability changes on solute transport simulations, this study conducted a salt transport experiment using a soil column with an upper sand layer, a middle clayey silt layer, and a lower sand layer. The experimental results showed that, under a constant hydraulic head difference, the flow rate decreased linearly, with a reduction exceeding 35 %. The solute penetration time increased significantly along the flow path. Using the velocity decay data, an advection-dispersion model that accounts for variations in flow velocity was developed. Additionally, an advection-dispersion model with constant flow velocity and a continuous time random walk (CTRW) model were also developed, both of which ignored velocity changes. Simulation results indicated that the variable flow velocity advection-dispersion model yielded the best results, followed by the CTRW model, with the constant flow velocity advection-dispersion model performing least effectively. When measured data on flow velocity changes are available, the variable flow velocity advection-dispersion model is recommended. If measured velocity change data are unavailable but the range of CTRW model parameters can be ascertained, the CTRW model is advisable. In the absence of ascertainable CTRW model parameter ranges and when the constant flow velocity advection-dispersion model is necessary, the advection-dispersion model with a constant maximum flow velocity should be employed.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"276 ","pages":"Article 104736"},"PeriodicalIF":4.4,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145149182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the fate of microplastics in multi-stage treatment units through distribution patterns and settling dynamics models","authors":"Kevin Daffa Prasetya ,&nbsp;Fahir Hassan ,&nbsp;Yu-Ting Yen ,&nbsp;Po-Yu Chen ,&nbsp;Jheng-Jie Jiang ,&nbsp;Ya-Fen Wang ,&nbsp;Sheng-Jie You","doi":"10.1016/j.jconhyd.2025.104734","DOIUrl":"10.1016/j.jconhyd.2025.104734","url":null,"abstract":"<div><div>Microplastics (MPs) are a new contaminant of global concern that have been found in wastewater treatment plants (WWTPs) as a result of human activities, which serve a dual function as critical barriers and pathways to natural waters and sludge-based applications. This study comprehensively evaluates the fate of MPs in multi-stage treatment units, covering both the water and sludge phases. It applies diversity assessments (Simpson Diversity Index [SDI], Shannon-Wiener Diversity Index [SWDI], and Principal Component Analysis [PCA]) and settling dynamics models (Mass Balance Model [MBM] and Terminal Settling Velocity Model [TSVM]). It was found that the concentration of MPs in water and sludge phases ranged from 2 to 1152 items/L and 35.65–85.05 × 10³ items/kg DW, respectively. MPs removal at the Taoyuan WWTP achieved 97.42 % after nitrite-denitrification and phosphorus removal (TNCU) processes. Despite these high removal rates, fibers and fragments dominate the MPs in the water phases (35.36 % and 14.25 %) and sludge phases (21.06 % and 17.26 %), which are mostly 50–125 μm in size. Further confirmation of the polymer characteristics in both matrices revealed that rayon (51.12 %) and polystyrene (36.59 %) were dominant, respectively. Subsequently, the diversity assessments showed greater variation and homogeneity of MPs characteristics in the sludge phases than in the water phases. Meanwhile, PCA results showed that specific MP characteristics (e.g., shape, size, polymer type) significantly influenced their grouping patterns across treatment stages. Among settling dynamics fate models implemented in this study, MBM confirmed that MPs are accumulated in the sludge phases, while TSVM indicated that the settling mechanisms of MPs was strongly influenced by their size and density. These findings offer new insights into MPs' fate and behavior in WWTPs, supporting the development of more effective mitigation strategies.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"276 ","pages":"Article 104734"},"PeriodicalIF":4.4,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}