Journal of contaminant hydrology最新文献

{"title":"Impact of humic acid on iron (oxyhydr)oxide transport in the presence of phosphate in saturated porous media","authors":"Tufail Shah ,&nbsp;Kang Zhao ,&nbsp;Yingjie Yin ,&nbsp;Jianying Shang","doi":"10.1016/j.jconhyd.2024.104444","DOIUrl":"10.1016/j.jconhyd.2024.104444","url":null,"abstract":"<div><div>The subsurface flow of particular phosphate (P) has been recently regarded as a vital P transport path. Humic acid (HA) and P usually coexist in the natural environment and show a strong affinity to iron (Fe) (oxyhydr)oxide. The impact of P and HA on Fe (oxyhydr)oxide stability and transport is critical for evaluating the vertical transport of particular P and biogeochemical processes of Fe and P. This study investigated the effect of inorganic (IP) and organic (OP) phosphate on the stability and transport of ferrihydrite and goethite with HA through stability tests and column experiments. The adsorption of IP or OP on Fe (oxyhydr)oxide enhanced the stability and transport of Fe (oxyhydr)oxide, and OP showed a stronger enhancement than IP due to its stronger binding capacity and more negative surface. Compared with ferrihydrite, goethite had fewer adsorption sites for IP or OP and showed strong stability and transport at low IP (50 μM) or OP (10 μM) concentration. HA decreased IP or OP adsorption on Fe (oxyhydr)oxide through competition adsorption and electrostatic repulsion. The formed ternary phosphate-Fe (oxyhydr)oxide-HA complex showed a more negative surface and strong stability and transport. Our findings provide direct insights into the distinct role of IP and OP on Fe (oxyhydr)oxide stability and transport in the presence of HA, which provides essential information for evaluating the transport of particular Fe (oxyhydr)oxide-facilitated P in soils and subsurface environments rich in iron, phosphate, and dissolved carbon.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104444"},"PeriodicalIF":3.5,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441899","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":"Time-lapse dielectric properties monitoring of the flow cell during DNAPL contamination and remediation processes by full-waveform inversion of GPR data using particle swarm optimization: A laboratory study","authors":"İsmail Kaplanvural ,&nbsp;Ertan Pekşen ,&nbsp;Nihat Hakan Akyol ,&nbsp;Doğukan Durdağ","doi":"10.1016/j.jconhyd.2024.104443","DOIUrl":"10.1016/j.jconhyd.2024.104443","url":null,"abstract":"<div><div>This study presents the monitoring of the contamination and remediation processes of an aquifer system using the ground-penetrating radar (GPR) method. To achieve this, periodic GPR measurements were performed on a flow cell, which was established to simulate aquifer contamination and remediation scenarios. The exterior of the flow cell was made of plexiglas, and a small hole was created at the top center to inject Dense Non-aqueous Phase Liquid (DNAPL) contamination. To study contaminant distribution and remediation processes, DNAPL Trichloroethylene (TCE) was used as the groundwater contaminant. Methyl-beta-cyclodextrin (MCD) was used as remediation agent. The interior of the flow cell was packed with two different sand grain size distributions: low permeability sand along the bottom and a higher permeability sand along the top. Common offset GPR measurements were performed along the top plane of the flow cell. The GPR measurements were conducted periodically over a total duration of 66 days, encompassing the phases prior to injecting DNAPL TCE, after injection of DNAPL TCE, and during the remediation process using MCD. Time-lapse GPR data were analyzed using 1D and 2D plots. In addition, to evaluate and monitor the contamination and remediation processes within the flow cell, central traces of the time-lapse GPR dataset were inverted by full-waveform inversion to estimate the dielectric properties of the layers and the depth by Particle Swarm Optimization (PSO). To utilize PSO, a forward model calculation using 1D finite difference in time domain adapted to PSO algorithm to generate theoretical GPR traces to compare the theoretical model GPR traces to the measured GPR traces as a “goodness of fit” metric. The electrical conductivity, relative dielectric permittivity, relative magnetic permeability, and depth of the layer were estimated by PSO of the GPR data. The results of the inversion process indicated a significant change in the estimated electrical conductivity values for the post TCE DNAPL contamination stage and the remediation stage. In addition, to support the inversion results, contaminant mass removal was quantified using moment analysis from dissolved-phase contaminant concentrations collected from the flow cell over time. According to the mass recovery calculation by moment analysis, which was collected via an outlet from the flow cell, approximately 38 % of the injected DNAPL TCE mass was removed by enhanced dissolution from the representative aquifer domain of the flow cell during the remediation stage of the experiment.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104443"},"PeriodicalIF":3.5,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417645","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":"How uncertainty in calibration data affects the modeling of non-point source pollutant loads in baseflow","authors":"Shuai Chen ,&nbsp;Wei Qin ,&nbsp;Tong Cui ,&nbsp;Jingling Qian ,&nbsp;Jiazhong Zheng","doi":"10.1016/j.jconhyd.2024.104441","DOIUrl":"10.1016/j.jconhyd.2024.104441","url":null,"abstract":"<div><div>Baseflow is a major transport pathway for non-point source (NPS) pollutants. Watershed water quality (WWQ) models calibrated by low-quality data may produce misleading predictions of baseflow NPS pollutant loads, resulting in poor management decisions. We evaluated how models of the baseflow nitrate loads in the Huron River basin, southwest of Lake Erie, were affected by uncertainty in the calibration data. Based on a five-year time series of daily streamflow, nitrate concentration, and specific conductance, two sets of “observed” baseflow nitrate load data that include uncertainty were estimated using various tracer-based and non-tracer-based hydrograph separation methods, in conjunction with assumptions regarding baseflow nitrate concentrations. We calibrated the Soil and Water Assessment Tool plus (SWAT+) model with the two “observed” data sets and used the Generalized Likelihood Uncertainty Estimation (GLUE) approach to quantify parameter and predictive uncertainties. The results showed that baseflow accounted for 26 %–34 % of the mean annual total streamflow (11.8 m³/s) and 8 %–37 % of the mean annual total nitrate load (14.3 kg·ha⁻¹·year⁻¹) in the Huron River basin. The baseflow and nitrate load estimates from the non-tracer-based methods resembled those from the tracer-based method but had greater uncertainty. The posterior parameter distributions, as well as the weighted means and 90 % prediction intervals of the simulated baseflow nitrate loads, exhibited minimal variation when different calibration data sets for SWAT+ and different threshold likelihood values for GLUE were used. Our analysis emphasizes the necessity of calibrating WWQ models with baseflow pollutant loads/concentrations when addressing water quality issues related to baseflow. It also demonstrates the feasibility of utilizing multiple non-tracer-based hydrograph separation methods to estimate baseflow NPS pollutant loads. These non-tracer-based methods offer a simplicity and broader applicability compared to tracer-based methods. This study has provided insights into how calibration data uncertainty impacts the modeling of NPS pollution in baseflow and highlights the practical value of non-tracer-based hydrograph separation methods.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104441"},"PeriodicalIF":3.5,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142437720","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":"Occurrence and visual characterization of microplastics from Mahakam River at Tenggarong City, Indonesia","authors":"Yudi Sukmono ,&nbsp;Tony Hadibarata ,&nbsp;Risky Ayu Kristanti ,&nbsp;Abhishek Singh ,&nbsp;Dunia A. Al Farraj ,&nbsp;Mohamed S. Elshikh","doi":"10.1016/j.jconhyd.2024.104440","DOIUrl":"10.1016/j.jconhyd.2024.104440","url":null,"abstract":"<div><div>Indonesia generates approximately 7.8 million tons of plastic waste annually, which 4.9 million tons is mismanaged. Presently, there is significant concern on microplastics (MPs) pollution in aquatic environment. The research on the prevalence of MPs in river systems are comparatively lower than the studies conducted on marine systems. The primary goal of this research was to look into the prevalence of MPs in the river water of Mahakam of Tenggarong City, Indonesia. To adequately represent this area, a meticulous selection method was used to find five separate sampling locations, with two stations at each location, positioned 200 m apart on opposite sides of the river. According to the study's findings, MPs has been observed in the range of 19.2 ± 1.8 to 58.5 ± 3.5 particles/l. Based on the MPs type, fragments (43.4 %) were the most common type of MPs found in water samples. Furthermore, 44.6 % of the MPs had size smaller than 1000 μm. The prevalent hues observed in the water samples were transparent and black, composing 75.6 % of overall formation. The determination of microplastic polymers employed Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy, revealing the presence of various type, such as polyethylene (PE) and polypropylene (PP).</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104440"},"PeriodicalIF":3.5,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the adsorption and interaction of P and Cd in polluted sediment from Dongting Lake","authors":"Ruifeng Zhu ,&nbsp;Mengya Xu ,&nbsp;Shunhong Huang ,&nbsp;Zexin He","doi":"10.1016/j.jconhyd.2024.104442","DOIUrl":"10.1016/j.jconhyd.2024.104442","url":null,"abstract":"<div><div>A series of experiments was performed to elucidate the effects of the adsorption and interaction of different concentrations of P and Cd on the availability of P and Cd. First, the sediments before and after maturation were subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy. The results revealed that the composition and main components of the sediment were unchanged by maturation. The adsorption results fitted by the Freundlich equation revealed that the maximum concentration of Cd in the sediment changed from 979.12 mg/L to 980.92 mg/L and 1215 mg/L after the addition of 1 mg/L and 2 mg/L P, respectively. The maximum concentration of P in the sediments increased from 397.57 mg/L to 403.19 mg/L and 422.89 mg/L after the addition of Cd concentrations of 5 mg/L and 50 mg/L, respectively. A batch experiment was subsequently performed with multiple groups of P and Cd at the same concentration. The results revealed that the content of available Cd was the highest when the content of P was 180 mg/kg and that the content of available P was the highest when the content of Cd was 1 mg/kg. However, when the concentrations of P and Cd exceeded a certain level, Cd₃(PO₄)₂ precipitated. Finally, the experimental results were reverified by XPS, and the results revealed that the contents of P and Cd in the sediments increased through adsorption and precipitation between P and Cd.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104442"},"PeriodicalIF":3.5,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417646","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":"Spectral induced polarization of corrosion of sulfur modified Iron in sediments","authors":"Hilary P. Emerson ,&nbsp;James E. Szecsody ,&nbsp;Christopher Halter ,&nbsp;Judy L. Robinson ,&nbsp;Jonathan N. Thomle ,&nbsp;Mark E. Bowden ,&nbsp;Odeta Qafoku ,&nbsp;C. Tom Resch ,&nbsp;Lee D. Slater ,&nbsp;Vicky L. Freedman","doi":"10.1016/j.jconhyd.2024.104439","DOIUrl":"10.1016/j.jconhyd.2024.104439","url":null,"abstract":"<div><div>Spectral induced polarization (SIP) responses are not well understood within the context of remediation applications at contaminated sites. Systematic SIP studies are needed to gain further insights into the complex electrical response of dynamic, biogeochemical states to enable the use of SIP for subsurface site characterization and remediation monitoring. Although SIP measurements on zero valent iron have been previously published, the SIP response for sulfur modified iron (SMI), a similar potential subsurface reductive amendment, has not yet been reported. Hence, the purpose of this laboratory-scale study was to evaluate SIP for nonintrusive monitoring of SMI under relevant subsurface conditions. SMI was separately mixed with silica sand or sediments from the Hanford Site (Washington, USA) and then packed into columns for geochemical and SIP analysis for up to 77 days under fully saturated conditions. SMI exhibited distinguishable phase peaks between 0.1 and 1.0 Hz, which changed in magnitude based on content and were detected as low as 0.3 wt%. In the initial days, the complex conductivity, phase maxima, and chargeability increased while the peak locations shifted to higher frequency (decreasing relaxation times), suggesting an initial increase in polarization and concurrent decrease in the length scales (potentially due to changes in particle size and mineralogy). Then, after 77 days, the phase maxima and chargeability decreased with a concurrent increase in relaxation times, suggesting that over longer periods, less polarizable phases are forming and particle size or connectivity of polarizable phases is increasing. These results demonstrated a unique SIP response to SMI transformations that might be applied to monitoring of SMI emplaced as a subsurface barrier or injected in the field.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104439"},"PeriodicalIF":3.5,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142377894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laboratory-scale study of mixed barriers in stratified layers with an inclined ocean aquifer boundary","authors":"Vikas Sharma,&nbsp;Sumedha Chakma","doi":"10.1016/j.jconhyd.2024.104438","DOIUrl":"10.1016/j.jconhyd.2024.104438","url":null,"abstract":"<div><div>The over-pumping of freshwater makes shoreline aquifers susceptible to seawater intrusion. Most studies on aquifer homogeneity that are used to form management guidelines focus on salinization sensitivity. However, under certain extraction conditions, the geographic structure can be quite diverse, with low-permeability obstacles and preferred flow routes that affect circulation and saline transport mechanisms. Here, we used a laboratory-scale glass box apparatus of dimension 100 × 50 × 10 cm³ to study intrusion in stratified layers under the influence of an inclined ocean-aquifer boundary with a mixed barrier as a remediation technique. The T_LH ratio ranged from 0.2 to 12.84 for all stratification conditions and remediation installed. There was a 40–48 % decrease in the extent of toe length after installation. With a mixed barrier installed, the height of the intrusion was reduced, resulting in an increase in the T_LH and a decrease in the potential for toe length. The intrusion was delayed by 86.67 % in parallel stratification and 28.22 % in perpendicular stratification after comparing the time frame for base case and the mixed barrier installed condition. A parabolic profile of intrusion was observed in the low-permeability layer, while a convex-outward profile was observed in the higher-permeability layers. Similar results are obtained after conducting the sensitivity analysis. The intrusion follows an increasing pattern of ratio with increasing interaction gap opening in parallel stratification, while for perpendicular stratification, with gap opening from 10 cm to 30 cm, there was a decreasing trend followed by an increasing trend, indicating an increase in magnitude with a similar pattern of intrusion. The results of this investigation shed light on the mixed barrier's suitability for use in realistically diverse coastal aquifers. Future research could explore the utilization of different combinations of new barriers, such as under-surface barriers, which work well for stratified layers, and already established barrier systems, to further improve the efficiency of mixed barriers.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104438"},"PeriodicalIF":3.5,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142347683","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 ensemble optimizer with a stacking ensemble surrogate model for identification of groundwater contamination source","authors":"Liuzhi Zhu ,&nbsp;Wenxi Lu ,&nbsp;Chengming Luo ,&nbsp;Yaning Xu ,&nbsp;Zibo Wang","doi":"10.1016/j.jconhyd.2024.104437","DOIUrl":"10.1016/j.jconhyd.2024.104437","url":null,"abstract":"<div><div>The application of the simulation-optimization method for groundwater contamination source identification (GCSI) encounters two main challenges: the substantial time cost of calling the simulation model, and the limitations on the accuracy of identification results due to the complexity, nonlinearity, and ill-posed nature of the inverse problem. To address these issues, we have innovatively developed an inversion framework based on ensemble learning strategies. This framework comprises a stacking ensemble model (SEM), which integrates three distinct machine learning models (Extremely Randomized Trees, Adaptive Boosting, and Bidirectional Gated Recurrent Unit), and an ensemble optimizer (<em>E</em>-GKSEEFO), which combines two newly proposed swarm intelligence optimizers (Genghis Khan Shark Optimizer and Electric Eel Foraging Optimizer). Specifically, the SEM serves as a surrogate model for the groundwater numerical simulation model. Compared to the original simulation model, it significantly reduces time cost while maintaining accuracy. The <em>E</em>-GKSEEFO, functioning as the search strategy for the optimization model, greatly enhances the accuracy of the optimization results. We have verified the performance of the SEM-<em>E</em>-GKSEEFO ensemble inversion framework through two hypothetical scenarios derived from an actual coal gangue pile. The results are as follows. (1) The SEM exhibits improved fitting performance compared to single machine learning models when dealing with high-dimensional nonlinear data from GCSI. (2) The <em>E</em>-GKSEEFO achieves significantly higher accuracy in the identification results of GCSI than individual optimizers. These findings affirm the effectiveness and superiority of the proposed SEM-<em>E</em>-GKSEEFO ensemble inversion framework.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104437"},"PeriodicalIF":3.5,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326767","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":"A convenient strategy for mitigating microplastics in wastewater treatment using natural light and ZnO nanoparticles as photocatalysts: A mechanistic study","authors":"Jeyaraj Jeyavani ,&nbsp;Khalid A. Al-Ghanim ,&nbsp;Marimuthu Govindarajan ,&nbsp;Guilherme Malafaia ,&nbsp;Baskaralingam Vaseeharan","doi":"10.1016/j.jconhyd.2024.104436","DOIUrl":"10.1016/j.jconhyd.2024.104436","url":null,"abstract":"<div><div>Polypropylene microplastics (PPMPs) are one of the major emerging contaminants in the ecosystem due to their frequent usage and improper disposal practices. These PPMPs enter ecosystems via wastewater effluent plants and cause severe environmental health issues. In addition, quantifying PPMPs smaller than 50 μm in wastewater plant extraction is very difficult. Thus, the current study was designed to mitigate the PPMPs using zinc oxide nanoparticles (ZnONPs) as a photocatalyst under sunlight. The photocatalytic reaction was examined using spectroscopic techniques and microscopic imaging. The findings indicated that the weight loss percentage of PPMPs increased, and a decrease in UV–Vis DRS peak intensities was observed. The spectroscopic results elucidated the formation of free radicals, which affect the PPMPs and lead to the formation of carbonyl, allylic, and unsaturated groups. Further, EDS reports clarified that there is increased oxygen content due to the photooxidation process and the disintegration of the polymer chain owing to decreased carbon levels. Overall, ZnO photocatalyst absorbs photons from the visible spectrum of sunlight and forms free radicals, which affect the PPMPs to initiate polymer deterioration. Also, the current study revealed the mechanistic pathway of PPMP degradation under the photocatalytic reaction as proposed in the results obtained above.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104436"},"PeriodicalIF":3.5,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142365432","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":"A numerical investigation to assess changes to displacement front and by-passed zones employing kinetic interface-sensitive tracer","authors":"H. Abdullah ,&nbsp;H. Gao ,&nbsp;M. Sauter ,&nbsp;A. Tatomir","doi":"10.1016/j.jconhyd.2024.104435","DOIUrl":"10.1016/j.jconhyd.2024.104435","url":null,"abstract":"<div><p>An important aspect in groundwater remediation is to understand changes of multiphase fluid front morphology and stagnant regions on macro scale. However, the prediction of those changes during two-phase flow remains a challenging task due to the interplay of various physical factors. Recent laboratory experiments have demonstrated tracers' ability to predict deformation in the front of a two-phase flow system by utilizing a new reactive tracer known as, the kinetic interface sensitive tracer (KIS). This research employs a reactive transport model coupled with a macro-scale two-phase flow model to numerically analyse how viscosity ratio, capillary number, and heterogeneities on the tracer's signal and its impact the frontal deformation. One homogeneous and two heterogeneous types of porous media are considered. The background porous medium is a fine-grained, low-permeability medium, with a coarser, high-permeability lenses, generating heterogeneous material properties. The high-permeability lenses account for 25 % of the total model area and are arranged in either periodic or random patterns. The findings are evaluated using four parameters (effective front length, swept area, front roughness, and transition zone length). The flow patterns dominating the shape of the front are characterized by the viscous and capillary forces i.e. capillary number and the viscosity ratio between the two fluids. The results show that changes in flow regimes can be quantified using effective front length, thus employing the effective front length the viscous fingering regions can be quantified. Furthermore, front roughness and transition zone length are extracted and their relevance to the by-passed zones is presented. The slope of the reactive KIS tracer breakthrough curve, plotted on a phase diagram, can also be used to predict the existence of the by-passed zones for a low viscosity ratio. Finally, changes in front roughness and transition zone length induced by the inclusions are correlated to the slope of the KIS tracer BTC. The findings of this study can contribute to a better understanding of the impact of different flow regimes on the KIS tracer breakthrough signals and the linkages between the tracer signals and the front sizes.</p></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104435"},"PeriodicalIF":3.5,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0169772224001396/pdfft?md5=0f497e3880f0021c1e24573e2287eb1b&pid=1-s2.0-S0169772224001396-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}