Importance of Infiltration Rates for Fate and Transport of Benzene in High-Tiered Risk-Based Assessment Considering Korean Site-Specific Factors at Contaminated Sites

Widely used conservative approaches for risk-based assessments of the subsurface transport processes have been calculated using simple analytical equations or general default values. Higher-tier risk assessment of contaminated sites requires the numerical models or additional site-specific values for input parameters. Previous studies have focused on the development of sophisticated models fit into risk-based frameworks. Our study mainly aims to explore the applicability of site-specific parameters and to modify the risk-based fate and transport model according to the types of the site-specific parameters. To apply the modified fate and transport equation and the site-specific default infiltration range, this study assessed the source depletion, leachate concentrations, and exposure concentration of benzene, which is a representative organic contaminant. The numerical models consist of two continuous processes, the fate and transport of contaminants from (1) the soil to the groundwater table in the vadose zone and subsequently (2) from the groundwater table to exposure wells in the saturated zone. Spatially varied Korean domestic recharge data were successfully incorporated into site-specific infiltration parameters in the models. The numerical simulation results were expressed as transient time series of concentrations over time. Results presented the narrow range of predicted concentrations at the groundwater table when site-specific infiltration was applied, and the dilution–attenuation factors for the unsaturated zone (DAFunsat) were derived based on the prediction. When a contaminant travels to the longest path length of 10 m with a source depth of 1 m in the vadoze zone, the simulated DAFunsat ranged from 3 to 4. The highest DAFunsat simulation results are close to 1 when contaminants travel to a source depth of 5 m and the shortest path length of 1 m. In the saturated aquifer below the contaminated sites, the variation in exposure concentration with time at monitoring wells is detected differently depending on the depth of the saturated zone.

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Chemical fate and transport in a domestic septic system: Unsaturated and saturated zone geochemistry

Environmental Toxicology and Chemistry ◽

10.1002/etc.5620130203 ◽

1994 ◽

Vol 13 (2) ◽

pp. 193-203 ◽

Cited By ~ 45

Author(s):

Sheryl R. Wilhelm ◽

Sherry L. Schiff ◽

William D Robertson

Keyword(s):

Fate And Transport ◽

Saturated Zone ◽

Septic System ◽

Chemical Fate

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Knowledge transfer from simulation to reality via Long Short-Term Memory networks: Estimating groundwater table depth anomalies over Europe

10.5194/egusphere-egu21-590 ◽

2021 ◽

Author(s):

Yueling Ma ◽

Carsten Montzka ◽

Bagher Bayat ◽

Stefan Kollet

Keyword(s):

Short Term Memory ◽

Scientific Data ◽

Groundwater Table ◽

Short Term ◽

Term Memory ◽

Continental Scale ◽

Groundwater Table Depth ◽

Long Short Term Memory ◽

Simulation Results

Near real-time groundwater table depth measurements are scarce over Europe, leading to challenges in monitoring groundwater resources at the continental scale. In this study, we leveraged knowledge learned from simulation results by Long Short-Term Memory (LSTM) networks to estimate monthly groundwater table depth anomaly (wtda) data over Europe. The LSTM networks were trained, validated, and tested at individual pixels on anomaly data derived from daily integrated hydrologic simulation results over Europe from 1996 to 2016, with a spatial resolution of 0.11&#176; (Furusho-Percot et al., 2019), to predict monthly wtda based on monthly precipitation anomalies (pra) and soil moisture anomalies (&#952;a). Without additional training, we directly fed the networks with averaged monthly pra and &#952;a data from 1996 to 2016 obtained from commonly available observational datasets and reanalysis products, and compared the network outputs with available borehole in situ measured wtda. The LSTM network estimates show good agreement with the in situ observations, resulting in Pearson correlation coefficients of regional averaged wtda data in seven PRUDENCE regions ranging from 42% to 76%, which are ~ 10% higher than the original simulation results except for the Iberian Peninsula. Our study demonstrates the potential of LSTM networks to transfer knowledge from simulation to reality for the estimation of wtda over Europe. The proposed method can be used to provide spatiotemporally continuous information at large spatial scales in case of sparse ground-based observations, which is common for groundwater table depth measurements. Moreover, the results highlight the advantage of combining physically-based models with machine learning techniques in data processing.&#160;Reference:Furusho-Percot, C., Goergen, K., Hartick, C., Kulkarni, K., Keune, J. and Kollet, S. (2019). Pan-European groundwater to atmosphere terrestrial systems climatology from a physically consistent simulation. Scientific Data, 6(1).

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Control Technology of Surface Movement Scope with Directional Hydraulic Fracturing Technology in Longwall Mining: A Case Study

Energies ◽

10.3390/en12183480 ◽

2019 ◽

Vol 12 (18) ◽

pp. 3480 ◽

Cited By ~ 2

Author(s):

Zhanjie Feng ◽

Wenbing Guo ◽

Feiya Xu ◽

Daming Yang ◽

Weiqiang Yang

Keyword(s):

Numerical Simulation ◽

Hydraulic Fracturing ◽

Longwall Mining ◽

Numerical Models ◽

Surface Subsidence ◽

The Sustainable Development ◽

Surface Movement ◽

Directional Hydraulic Fracturing ◽

Simulation Results ◽

Overlying Strata

Mining-induced surface subsidence causes a series of environmental hazards and social problems, including farmland destruction, waterlogging and building damage in the subsidence area. To reduce mining damages, an innovative method of controlling the surface movement scope via artificial weak planes generated by hydraulic fracturing technology was proposed in this paper. Numerical models were built to analyze the influence of weak planes with different heights and dips on the overlying strata movement. The numerical simulation results showed that the weak planes structure cut off the development of the overlying strata displacement to the surface and affected the surface movement scope. When the weak planes’ dips were bigger than the angle of critical deformation, with the increase of the weak planes’ heights (0–120 m) the advance angle of influence changed from 53.61° to 59.15°, and the advance distance of influence changed from 173.31 m to 140.27 m which decreased by 30.04 m. In applications at Sihe coal mine in China, directional hydraulic fracturing technology was used in panel 5304 to form artificial weak planes in overlying strata. The measured surface subsidence and deformation value met the numerical simulation results and the mining-induced surface movement scope reduced. Moreover, no damage occurred to the surface buildings which were predicted to be in the affected area after extraction. This technology provided a new method to protect the surface structures from damages and had great benefits for the sustainable development of coal mines.

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Flow Ripple Reduction of Axial-Piston Pump by Structure Optimizing of Outlet Triangular Damping Groove

Processes ◽

10.3390/pr8121664 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1664

Author(s):

Haocen Hong ◽

Chunxiao Zhao ◽

Bin Zhang ◽

Dapeng Bai ◽

Huayong Yang

Keyword(s):

Numerical Models ◽

Structural Parameters ◽

Piston Pump ◽

Axial Piston Pump ◽

Discharge Flow ◽

Flow Ripple ◽

Ripple Reduction ◽

Simulation Results ◽

The Time Domain ◽

Axial Piston

The triangular damping groove on the valve plate can effectively reduce the discharge flow ripple of an axial piston pump, which structural parameters will directly affect the pump’s dynamic characteristics. Herein, a multi-parameter data-based structure optimizing method of the triangular damping groove is investigated using numerical models and simulation results. The mathematical models of a nine-piston pump are proposed and developed by MATLAB/Simulink, and the simulation results are verified by experimental results. Then, the effects of width angle and depth angle on discharge flow are analyzed. Based on the analysis of groove parameters, an optimizing index, which considering the time domain characteristics of discharge flow, is proposed. As results show, comparing with the initial specific groove structure, the amplitude of flow ripple is reduced from 14.6% to 9.8% with the optimized structure. The results demonstrate that the outlet flow ripple can be significantly reduced by the optimized structure, and the proposed multi-parameter optimizing method can play a guiding significance in the design of low-ripple axial piston pumps.

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Simulation Research of Effect of Salinity Wastewater Discharging Ways on Range of Salt Content Rise Nearby the Outfall

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.777.440 ◽

2013 ◽

Vol 777 ◽

pp. 440-443

Author(s):

Yao Chen ◽

Li Li ◽

Bai Lu Yang ◽

Chun Long Li

Keyword(s):

Salt Concentration ◽

Single Port ◽

Numerical Models ◽

Salt Content ◽

Three Dimensional ◽

Simulation Research ◽

Subcritical Flow ◽

Simulation Results ◽

Salinity Wastewater ◽

Better Than

In order to study the effect of salinity wastewater discharging ways on the range of salt content rise nearby the outfall. Two three-dimensional numerical models of discharging ways which were single-port submerged-type and double-port submerged-type in the condition of subcritical flow were researched based on FLUENT. The range of salt content rise of the two discharging ways could be concluded according to the simulation results. The value of maximum salt concentration and average salt concentration of two discharging ways were compared and analyzed. The results showed that double-port submerged-type discharging way was better than single-port submerged-type discharging way.

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The use of Runoff and Surface Water Transport and Fate Models in the Pesticide Registration Process

Weed Technology ◽

10.1017/s0890037x00036149 ◽

1992 ◽

Vol 6 (3) ◽

pp. 743-748 ◽

Cited By ~ 4

Author(s):

Paul L. Zubkoff

Keyword(s):

Surface Waters ◽

Environmental Fate ◽

Transport Model ◽

Numerical Models ◽

Chemical Properties ◽

Chemical Characterization ◽

Fate And Transport ◽

Environmental Parameters ◽

Field Studies ◽

Chemical Application

In support of the registration and reregistration processes under FIFRA ‘88, numerical models are used to estimate the dissolved runoff and soil erosion loadings of pesticides to surface waters and the subsequent fate and transport of pesticides in the receiving waters. Uses for simulations include:1. Helping to determine whether additional studies on the fate and distribution of a candidate chemical in the environment and/or ecological effects may be needed when full chemical characterization is incomplete.2. Helping to more fully integrate data submissions of laboratory and field observations.3. Estimating probable fate and distribution of an agrochemical after a severe runoff event.4. Comparing alternative chemical application rates and methods for the same chemical/soil/crop/environmental combinations.5. Comparing different soil/crop/environmental combinations representing different geographical areas with the same chemical.6. Evaluating preliminary designs of proposed field studies.7. Gaining insight into the environmental fate of modern chemicals that are applied at 1 to 2% of the rates of older chemicals when sampling designs and analytical methods are not available.The Office of Pesticide Programs (OPP) commonly employs the SWRRB (45, 46) and PRZM (8, 9) models for runoff and EXAMS II (5), a fate and transport model, for surface waters. These three models are used in conjunction with appropriate databases for soils, chemical properties, and meteorological and other environmental parameters. Registrants are encouraged to clearly state assumptions, identify values for parameters by citation, report results of simulations with summary tables and graphics, and interpret their results in relation to current scientific disciplines.

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3D Simulation of Tunnel Collapse Consolidation and In Situ Monitoring Analysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.3551 ◽

2011 ◽

Vol 243-249 ◽

pp. 3551-3555

Author(s):

Zhi Min Chen ◽

De An Zhao

Keyword(s):

Numerical Models ◽

Three Dimensional ◽

In Situ Monitoring ◽

3D Simulation ◽

Actual Situation ◽

Consolidation Effect ◽

Tunnel Collapse ◽

Simulation Results ◽

Shallow Buried Tunnel

A shallow buried tunnel was collapsed during construction. According to the actual situation of the tunnel, different collapse consolidation schemes were put forward and corresponding three-dimensional finite difference numerical models were established and analyzed using FLAC3D software. Base on the 3D Simulation results, a collapse consolidation scheme was determined and constructed. The in-situ monitoring results of vault subsidence and convergence displacement were consistent approximately with the 3D Simulation results. The in-situ measured results were in line with the specification’s allowance and show that the consolidation effect of reinforced concrete casing arch and ahead grouting method is good. This could be referenced for similar engineering.

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Assessment of Intrinsic Biodegradation Potentials in an Aquifer Contaminated with Chlorinated Ethenes in the Vicinity of Nowa Deba

Ecological Chemistry and Engineering S ◽

10.2478/eces-2013-0019 ◽

2013 ◽

Vol 20 (2) ◽

pp. 265-278 ◽

Cited By ~ 3

Author(s):

Aleksandra Kiecak ◽

Ewa Kret ◽

Monika Cichostępska ◽

Grzegorz Malina

Keyword(s):

Risk Reduction ◽

Natural Attenuation ◽

Chlorinated Solvents ◽

Fate And Transport ◽

Site Specific ◽

Preliminary Screening ◽

Natural Processes ◽

The Us ◽

Time Frames

Abstract Natural Attenuation (NA) in the case of groundwater contaminated with organic compounds relies mainly on intrinsic biodegradation processes. The aim of reliance on natural processes is to achieve site-specific cleanup objectives within reasonable time frames and costs. Such approach may be considered as a risk reduction/remedial option for groundwater contaminated with trichloroethene (TCE) and tetrachloroethene (PCE). This case study presents implementation of the US EPA’s guideline „Technical protocol for evaluating natural attenuation of chlorinated solvents in groundwater” to asses intrinsic biodegradation potentials in TCE and PCE contaminated groundwater in the vicinity of Nowa Deba waterworks (south-east Poland). Literature and field data collected from wells and piezometers were used to develop a conceptual model of contaminants’ fate and transport from a source to a receptor. The intrinsic biodegradation was investigated basing on available analytical parameters (eg concentrations of oxygen, nitrates, chlorides, and pH, TOC and temperature) that are considered as indicators of TCE and PCE transformation. Preliminary screening was done by giving certain points for these parameters, and interpreted in order to asses intrinsic biodegradation potentials. The results indicate inadequate evidence for intrinsic biodegradation (reductive dehalogention) of TCE and PCE, thus a limited potential for NA as a remedial/risk reduction option in the studied case, unless some measures for enhancement of TCE and PCE intrinsic biodegradation are applied.

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Impacts of Spatial Zonation Schemes on Yield Potential Estimates at the Regional Scale

Agronomy ◽

10.3390/agronomy10050631 ◽

2020 ◽

Vol 10 (5) ◽

pp. 631 ◽

Cited By ~ 1

Author(s):

Hao Xu ◽

Fen Huang ◽

Wenjun Zuo ◽

Yongchao Tian ◽

Yan Zhu ◽

...

Keyword(s):

Growth Models ◽

Sunshine Duration ◽

Regional Scale ◽

Crop Growth ◽

Yield Potential ◽

Specific Yield ◽

Site Specific ◽

Spatial Zonation ◽

Simulation Results ◽

Crop Growth Models

Simulations based on site-specific crop growth models have been widely used to obtain regional yield potential estimates for food security assessments at the regional scale. By dividing a region into nonoverlapping basic spatial units using appropriate zonation schemes, the data required to run a crop growth model can be reduced, thereby improving the simulation efficiency. In this study, we explored the impacts of different zonation schemes on estimating the regional yield potential of the Chinese winter wheat area to obtain the most appropriate spatial zonation scheme of weather sites therein. Our simulated results suggest that the upscaled site-specific yield potential is affected by the zonation scheme and by the spatial distribution of sites. As such, the distribution of a small number of sites significantly affected the simulated regional yield potential under different zonation schemes, and the zonation scheme based on sunshine duration clustering zones could effectively guarantee the simulation accuracy at the regional scale. Using the most influential environmental variable of crop growth models for clustering can get the better zonation scheme to upscale the site-specific simulation results. In contrast, a large number of sites had little effect on the regional yield potential simulation results under the different zonation schemes.

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